Rajini Rao2011-12-11 19:19:00
Smallest rotary motor in biology, the ATP synthase. All the work done in your body is fueled by breaking a chemical bond in ATP, the “currency of energy”. Did you know that you convert your body weight (or an estimated 50 kg) of ATP per day?!

Where does this ATP come from? It is synthesized by an incredibly sophisticated molecular machine, the ATP synthase, embedded in the inner membrane of our mitochondria. Energy from the oxidation of food results in protons being pumped across the membrane to create a proton gradient. The protons drive the rotation of a circular ring of proteins in the membrane that in turn move a central shaft. The shaft interacts sequentially with one of 3 catalytic sites within a hexamer, making ATP (little butterflies in the movie!). The ATP synthase rotates about 150 times/second

To visualize the rotation under a microscope, a very long fluorescent rod (actin filament) was chemically attached to the central shaft. Watch real movies (not animations!) of the enzyme spinning here: http://www.k2.phys.waseda.ac.jp/F1movies/F1long.htm

Notice the rotation is slower with longer rods. The rotor produces a torque of 40 pN nm (40 pico Newtons x nanometer), irrespective of the load. This would be the force you would need to rotate a 500 m long rod while standing at the bottom of a large swimming pool at the rate shown in the movie.

How did this amazing rotor evolve? The hexameric structure is related to DNA helicases that rotate along the DNA double helix, using ATP to unzip the two strands apart. The H+ motor has precedence in flagella motors that use proton gradients to drive rotation of long filaments, allowing bacteria to tumble through their surroundings. At some point, a H+ driven motor came together with a helicase like hexamer to create a rotor driving the hexamer in reverse, to synthesize ATP.

The 1997 Nobel prize in Chemistry was awarded to John Walker and Paul Boyer for solving the structure and cyclical mechanism of the ATP synthase, respectively. This amazing enzyme was also the subject of my own Ph.D. thesis, and my first love!

For #ScienceSunday curated by +Allison Sekuler and +Robby Bowles .
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  • Rajini Rao2012-04-30 12:20:27
    SURREAL CIRCLES: In his series Alternative Perspectives, photographer Randy Scott Slavin portrays a 360 degree view of our world by seamlessly stitching together hundreds of shots. The result is surreal art, grounded in reality. He inspires us to "go out and explore the world and take a look at the monuments and reimagine them in a different way".

    Source: http://goo.gl/2Ut69
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  • Rajini Rao2012-08-25 10:12:12
    All for a Pail of Water: This touching photograph shows tribal women in India risking their lives in a human chain to reach water from an agricultural well. Did you know that 1 in 6 people on our planet lack access to clean drinking water? New research offers an elegantly simple solution: sun, lime juice and salt . No, it's not the recipe for a margarita! :)

    What is SODIS? When water in a clear plastic bottle is placed in direct sunlight for 6 hours, the heat and ultraviolet light destroys most viruses, bacteria and parasites. This technique of Solar Disinfection reduces diarrhea and cholera by 70-80%, diseases that claim 4000+ childhood deaths per day in Africa. Researchers at Johns Hopkins University recently showed that adding juice from half a lime per bottle significantly reduced bacterial load and speeded up the process to just 30 minutes, comparable to boiling or other methods of disinfection. Lime juice contains psoralens which form covalent crosslinks between DNA strands in the presence of sunlight, a reaction that prevents DNA replication in the pathogens.

    Lurking in the Murk: When the water drawn from rivers and boreholes is turbid, SODIS does not work well, since the microbes hide out under suspended particles of clay and silt. A study showed that adding a quarter teaspoon of table salt to the water neutralized charges on colloidal clay so that it sedimented out easily. Seeding the water with a little clay (of the type known as bentonite) actually hastens the clarification!

    #scienceeveryday FTW! Simple solutions for #Glia .

    Further (Free) Reading: http://goo.gl/QRNuO
    Photo Credit: G.N.Rao, The Hindu . http://www.thehindu.com/news/national/article221561.ece
    
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  • Rajini Rao2012-04-08 03:36:04
    Destination: Lítla Dímun This cloud covered muffin top is in the Faroe Islands, Kingdom of Denmark. Population: humans (0), European Storm Petrels (5000 pairs) and Atlantic Puffins (10,000 pairs). There are also herds of sheep that are rounded up each fall and lowered using nets to waiting skiffs below.
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  • Rajini Rao2012-08-26 16:28:28
    Spiders on Speed: NASA scientists inexplicably investigated web spinning by stoned spiders. Turns out that the geometrical structure of a web provides a good measure of the condition of its central nervous system.

    LSD: Webs took on a minimalist structure.

    Marijuana: Spiders made a reasonable stab at spinning webs but appeared to lose concentration about half-way through.

    Amphetamine ("speed"): Webs retained their size but showed an increase in spiral spacing and radius irregularity, as well as a decrease in building efficiency. Spiders spin their webs "with great gusto, but apparently without much planning leaving large holes", according to New Scientist magazine.

    Caffeine: makes spiders incapable of spinning anything better than a few threads strung together at random.

    Chloral hydrate (an ingredient of sleeping pills): spiders "drop off before they even get started".

    In slightly more relevant work, spiders were shown to spin perfectly good webs in microgravityhttp://goo.gl/0T7lK

    Source: http://www.trinity.edu/jdunn/spiderdrugs.htm
    Pubmed: http://goo.gl/I3U1Q

    Extrapolation to Humans: Stunning "under the influence" self portraits of artist Bryan Lewis Saunders in +Feisal Kamil's post here ▶ http://goo.gl/3xYSy  Warning: Do not try this at home!

    Confession: Since I'm jet lagged and awake since midnight, I've been abusing caffeine. I won't post a picture of my web. 

    Hilarious "mocumentary": Spiders On Drugs

    #sciencesunday +ScienceSunday #spidersunday  
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  • Rajini Rao2012-02-05 16:31:58
    The Double Helix: Top Ten Amazing Facts about DNA!

    • You have an estimated 3 billion DNA bases in your genome.

    • Your genome would occupy about 3 gigabytes of computer storage space or fill 200 1,000-page New York City telephone directories.

    • It would take a person typing 60 words per minute, eight hours a day, around 50 years to type out all the letters of your genome.

    • If unwound and tied together, the strands of DNA in one cell would stretch almost six feet but would be only 50 trillionths of an inch wide.

    • If you unwrap all the DNA you have in all your cells it would reach to the sun and back over 600 times (100 trillion times six feet divided by 92 million miles).

    • You have an estimated 20,000 to 25,000 genes, but they only make up 2-3% of your genome. We are just starting to understand the function of your remaining “junk”.

    • Over 99.9% of your DNA sequence is the same as mine!

    • You have 1-4% Neanderthal DNA; some of you may have more :)

    • The first human genome was patched together over 13 years; today, your genome can be commercially sequenced in 2-3 months.

    • Costs for sequencing the genome are falling exponentially: from USD 3 billion in 2001 to USD1,000 today and may fall by another factor of ten!

    So, what's in your genes?
    ___________________________________________________________
    Awesome enough for you? Want more? Check out: http://www.eyeondna.com/2007/08/20/100-facts-about-dna/
    http://bionumbers.hms.harvard.edu/search.aspx?log=y&task=searchbytrmorg&trm=dna&time=2012%2f01%2f28+16%3a12%3a18.418
    Thanks to +Dunken K Bliths for generating this wonderful gif!
    Thank you +Konstantin Makov , for finding this hypnotic image :)
    #sciencesunday curated by +Allison Sekuler and +Robby Bowles .
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  • Rajini Rao2012-02-08 13:58:09
    Bug Eyes are Beautiful! If the eyes are a window to our souls, then these gorgeous compound eyes will surely win you over.

    • Each tiny facet (ommatidium) has a lens leading into a crystalline cone with light sensitive cells arranged like the segments of an orange. Individual eyes are insulated from others by a lining of pigment. The final image is a mosaic of light and dark dots, like the halftone illustrations in a newspaper. More ommatidia give a finer pattern of dots and a better resolution. Even so, the resolution of insect eyes is nowhere near that of ours: images we can separate at 60 feet would have to be one foot away to be distinguished by a honey bee.

    • The big advantage to compound eyes is that they pick up movements very well because ommatidia can quickly turn on and off to give a flicker effect. Ever tried to swat a fly? Insects can see ultraviolet too.

    These images were taken by photographer +Thomas Shahan . Checkout more insect macrophotography at: http://thomasshahan.com/photos

    More on compound eyes: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CompoundEye.html
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  • Rajini Rao2012-01-23 13:55:06
    Talent and humor, ¡Bravo! Slovakian musician Lukáš Kmit was playing a lovely piece on his viola when he was interrupted by a Nokia ringtone (0:40 into the video). What a charming, humorous response!

    P.S. The Nokia ringtone originated from a classic 1902 piece by Spanish guitarist Francisco Tárrega called “Gran Vals.” It is lovely: Gran Vals - Francisco Tárrega

    Source: http://mashable.com/2012/01/22/nokia-ringtone-interrupts/
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  • Rajini Rao2012-03-08 13:34:41
    First Women in STEM: A Tribute to International Women’s Day. Here is a celebration of some of the brilliant women who changed the course of history for the better. Women of G+ , do you have stories of your own to share? What personal achievement are you proud of, whether in your family, community or profession?

    Marie Curie: First woman to receive a Nobel Prize, once for Physics (1903) and then again for Chemistry (1911), she pioneered the study of radioactivity. She died of aplastic anemia brought on by lethal exposure to radiation. Despite her two Nobels, she was not elected to the French Academy of Sciences by two votes.

    Mary Kies. Hats off to the First woman granted a US patent (1809) for a process to weave straw with silk or thread in hat making. This was a time when women could not legally own property independent of their husbands. Her patent is credited with boosting American industry at a time when Napoleon imposed a blockade on export of European goods.

    Ada Lovelace: Charles Babbage called her Enchantress of Numbers, History calls her First Programmer. Daughter of Lord Byron, in 1843, her notes on the Analytical Engine are credited as the first algorithm intended to be processed by a machine.

    Elizabeth Garrett Anderson: physician and feminist, first woman qualified to practice in England (1865), created a medical school for women, first Dean of a medical school, first woman to be elected to a school board and first woman mayor and magistrate in Britain. The day she passed the licensing exam, with highest marks, the Society of Apothecaries immediately amended their rules to prevent other women from obtaining a license.

    Florence Sabin: First woman faculty at Johns Hopkins medical school (MD, 1900 from the first batch of female medical students admitted), she was also first woman to achieve Professorship there (1917), to be elected to the National Academy of Science, and head a department at Rockefeller Institute (she was passed over for Department Head at Hopkins, in favor of her own student, a male).

    Valentina Tereshkova: Russian cosmonaut who was the First woman in space, in 1963, aboard Vostok 6. She completed 48 orbits in 71 hours. Her call sign was Chaika (seagull), a nickname that she carries to this day. She turned 75 two days ago.

    Whom did I leave out of this very short and inadequate list?
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  • Rajini Rao2012-01-21 13:41:18
    Gutsy school children. School children in Lebak, Indonesia cling perilously to a damaged rope bridge across the Ciberang river to get to school. Hopefully this publicity will mean that the bridge gets repaired quickly.

    Reuters video in the link.
    Source: http://www.nydailynews.com/news/world/brave-kids-indonesia-walk-damaged-bridge-river-school-article-1.1009218
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  • Rajini Rao2014-04-11 21:45:27
    On The Shoulders of Giants

    ♀ A sepia print of an Indian woman, a Japanese woman and a woman from Syria, dated 1885. What do they have in common? Extraordinarily, each was the first licensed female medical doctor in their country of origin. They were trained at the Women's Medical College in Pennsylvania, the first of its kind in the country. This was a time before women had the right to vote. If they did attend college at all, it was at the risk of contracting "neuralgia, uterine disease, hysteria, and other derangements of the nervous system” (according to Harvard gynecologist Edward H. Clarke). 

    An all-woman medical school was first proposed in 1846, supported by the Quakers and the feminist movement. Dr. Ellwood Harvey, one of the early teaching faculty, daringly smuggled out a slave, Ann Maria Weems, dressed as a male buggy driver, from right outside the White House. With his reward money, he bought his students a  papier maché dissection mannequin. Eventually, poverty forced him to quit teaching, but he still helped out with odd jobs. What a magnificent man!  

    Fate and fortune were to buffet Ms. Joshi's life. Married at age 9 to a man 11 years older, her husband turned out to be surprisingly progressive. After she lost her first child at age 14, she vowed to render to her "poor suffering country women the true medical aid they so sadly stand in need of and which they would rather die than accept at the hands of a male physician". She was first offered a scholarship by a missionary on condition that she converted to Christianity. When she demurred, a wealthy socialite from New Jersey stepped in and financed her education. She is believed to be the first Hindu woman to set foot on American soil. I didn't arrive until 1983 ;)

    Times were tough then. The fate of these three intrepid pioneers was a sad one. Joshi died of tuberculosis in India at the age of 21, without ever practicing. Fittingly, her husband sent her ashes back to America. Islambouli was not heard of again, likely because she was never allowed to practice in her home country. Although Okami rose to the position of head of gynecology at a Tokyo hospital, she resigned two years later when the Emperor of Japan refused to meet her because she was a woman. 

    Times have changed. My own mother was married at the age of 13 to a man also 11 years her senior. My father recalls helping my mother with her geography homework in high school. She never did attend college, despite being a charismatic woman with quicksilver wit and efficiency. Little wonder then, when I was accepted into graduate school in the US, unmarried and 21 years young, my parents staunchly stood behind me against the dire predictions of friends and relatives ("She'll come back with a yellow haired American!" "Haven't you read Cosmopolitan magazine? They are all perverts there!"). Happily, I escaped perversion, earned my doctoral degree and even gained a supportive spouse of my own. In 2004, I became only the 103rd woman to be promoted to Professor in the 111-year history of the Johns Hopkins medical school, and the first in my department, the oldest Physiology department in the country. If I have seen further it is by standing on the shoulders of giants

    #STEMwomen   #ScienceEveryday  

    More reading: http://www.pri.org/stories/2013-07-15/historical-photos-circulating-depict-women-medical-pioneers
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  • Rajini Rao2013-02-02 22:10:05
    The Cosmos: Macro versus Micro

    ☼ The images on the left are night views of brightly lit metropolitan cities taken from the International Space Station. On the right, are fluorescent images of neurons. Like a neuron, the city seems to have a cell body, branching dendrites and a main axon like highway extending out.

    ☼ The ancient Greeks of the Neo-Platonic school of philosophy saw  the same patterns reproduced in all levels of the cosmos, from the largest scale (macrocosm or universe-level) all the way down to the smallest scale (microcosm or sub-sub-atomic or even metaphysical-level). In their philosophy, Man is in the middle.

    ☼ Did you know that the word cosmos (Greek, κόσμος) means "order" and is the conceptual opposite of "chaos"? In Mandarin Chinese, cosmos and universe are both translated as 宇宙 yǔzhòu, which means "space-time".

    “To see a World in a Grain of Sand
    And a Heaven in a Wild Flower,
    Hold Infinity in the palm of your hand
    And Eternity in an hour.”

    -William Blake

    Source: http://infinity-imagined.tumblr.com/page/6

    #ScienceSunday
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  • Rajini Rao2012-04-28 02:08:15
    WHEN EINSTEIN MET TAGORE: An attempt to explain Truth and Beauty at the intersection of Science and Spirituality. It was July 14, 1930 when Einstein met Rabindranath Tagore- poet, polymath and first non-European to win the Nobel for Literature (for Gitanjali).

    Regardless of your philosophy, religion or lack thereof, the following conversation will blow your mind. Excerpt:

    EINSTEIN: Truth, then, or Beauty is not independent of Man?
    TAGORE: No.
    EINSTEIN: If there would be no human beings any more, the Apollo of Belvedere would no longer be beautiful.
    TAGORE: No.
    EINSTEIN: I agree with regard to this conception of Beauty, but not with regard to Truth.
    TAGORE: Why not? Truth is realized through man.

    Read more here: http://www.brainpickings.org/index.php/2012/04/27/when-einstein-met-tagore/

    The conversation goes from the tangibility of a table to Pythagorean geometry, concluding with:

    EINSTEIN: Then I am more religious than you are!
    TAGORE: My religion is in the reconciliation of the Super-personal Man, the universal human spirit, in my own individual being.

    Many Thanks to +Pravin Bhojwani for the original share!
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  • Rajini Rao2013-12-29 23:38:50
    The Biology of Transparency

    The Invisible Man: Have you ever wished to be invisible? Transparency is quite common in biology, being particularly useful as camouflage in the open ocean where there is nothing to hide behind. There is an astonishing variety of transparent jellyfish, glass squid, worms and this creepy-crawly crustacean from the "twilight zone" of the deep sea seen in the image. 

    How does it work? To be transparent, light must pass through without being absorbed or scattered. Most organic molecules do not absorb light in the visible range, except for the visual pigments of the eyes, which must absorb light to function. Light scattering is caused by changes in refractive index which determines how light is bent as it passes through (see http://goo.gl/7l6zFC). To be perfectly transparent, the refractive index should be the same throughout. This is clearly a challenge in biological tissues, where lipid membranes and protein/DNA rich organelles (like mitochondria or nuclei) are much denser than the surrounding cytoplasm. So transparent animals resort to a number of tricks to avoid light scattering.

    See Right Through Me: One way is to become extremely flat! Since there is an exponential relationship between thickness and light absorption/scattering, a 1 cm thick tissue that is 60% transparent will achieve 95% transparency if it is only 1 mm thick. Some tissues, like the lens of our eyes, undergo drastic reduction of complexity, relying on neighboring cells to feed them. At the ultrastructural level, surfaces can be cloaked in submicroscopic bumps, smaller than half the wavelength of light that average out the differences in refractive indexes. Known as moth eye surfaces, these are responsible for the transparency of the beautiful glasswing butterfly Greta oto (see http://goo.gl/KS85mo).

    I See You!: It's hard to keep the gut transparent, unless one only eats transparent food, like the larvae of the phantom midge that sucks out clear fluids from its prey. Also, transparency can be foiled by predators that have evolved to use UV light or even polarized light to spot their prey, since underwater light is polarized particularly in the horizontal plane. A study with squid showed that they attacked plastic beads with birefringence, preferentially over beads without this optical property. Something to think about before you invest in an invisibility cloak!

    GIF: This 9 cm long amphipod is nearly completely transparent. Via http://goo.gl/bL14Oy from the video below.

    Video: For a short 2:41 minute video of more stunning transparent creatures, watch Deep Sea Creatures - Nature's Microworlds - Episode 11 Preview - BBC Four

    REFhttp://biology.duke.edu/johnsenlab/pdfs/pubs/transparencyreview.pdf

    Musical InspirationQueen - 'The Invisible Man'

    #ScienceSunday   #ScienceEveryday  
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  • Rajini Rao2012-02-28 23:09:28
    Art or Alcohol? Scientist Michael Davidson began taking photomicrographs of alcohol in the 1990's to raise funds for his lab. He crystallized samples of beer, tequila, vodka and other liquors on a slide, then imaged them under polarized light to reveal these gorgeous colors. You can purchase them as prints for your wall from bevshots.com.

    Note: I've not been able to post science-y stuff all week as I am carousing (er, conferencing) with 5000+ biophysicists in sunny San Diego. This collection of photographs seems particularly appropriate ;)

    H/T to Huff Post Arts for featuring this story: http://www.huffingtonpost.com/2012/02/27/artsy-side-of-alcohol_n_1304880.html#s731641
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  • Rajini Rao2012-02-26 13:55:17
    WHO declares India polio-free! An incredible feat for a nation once the polio epicenter with 200,000 cases in 1988. As recently as 2009, India accounted for half of all cases in the world, but infections plummeted to 42 in 2010 and none in the last 12 months. The Indian government has spent $2 billion over the last 10-15 years to eradicate this crippling disease, which strikes children under the age of 5. However, 3 other countries (Nigeria, Afghanistan and Pakistan) have reported a massive increase in new polio cases.

    More: http://timesofindia.indiatimes.com/india/WHO-takes-off-India-from-polio-list/articleshow/12038508.cms
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  • Rajini Rao2013-03-21 23:13:10
    Down Syndrome Day

    Today, 3/21, is World Down Syndrome Day. Also known as Trisomy 21, because it involves three copies of chromosome 21 instead of the usual two (see image), Down syndrome is the most complex of genetic disorders that is compatible with survival (other trisomies are more common, but are lethal). Even Down syndrome is associated with ~50% lethality of embryos. In the US, 1 in 691 babies is born with Down syndrome.

    Too much of a good thing: Anywhere from 300 to 500 genes have altered levels and function, resulting 80 or 90 possible symptoms and an instantly recognizable phenotype (physical appearance). For example, patients have a 1 in 5 chance of developing a hole in the heart, compared to an incidence of 1:10,000 in the normal population. Down syndrome is extraordinarily complex, and my friend and colleague Roger Reeves has dedicated his career to helping patients with his research.

    Cerebellar size: Dr. Reeves showed that the reduced size of the cerebellum in patients was due to defects in the sonic hedgehog signaling pathway. Using a drug that activated this pathway, he was able to restore the number of cerebellar cells to normalcy in a mouse model of Down syndrome, pointing to a therapeutic potential for the central nervous system deficits in patients.

    Tweaking circuits: In the hippocampus—that part of the brain that’s used to navigate landmarks and fix memories, Down syndrome patients show an excess of inhibitory pathways compared to excitatory ones. A drug that is already FDA-approved works wonders on mice with the equivalent of Down syndrome, restoring balance to their brain. This drug is now in clinical trials for  Down syndrome patients.

    It's not all bad: Research on Down syndrome has broad impact. For example, having three copies of a tumor suppressor gene means that patients have a 93% lower incidence of developing certain cancers. This insight could help treat cancers in the general population. Plus, as Roger likes to say, if you know anyone with Down syndrome, they tend to be pretty interesting individuals in their own right.

    For more on Roger's research: http://goo.gl/uSJWm

    #ScienceEveryday #DownSyndrome  
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  • Rajini Rao2013-02-23 18:24:34
    Chameleon Catapult

    Chameleons are among the slowest moving reptiles. But their protruding eyes swivel independently for a 360 degree range, so they can look for prey in different directions at the same time. When a hapless insect victim is detected, both eyes focus on it to judge range and distance with superb accuracy. 

    Ballistic Brilliance! The chameleon then launches its tongue, which is 1.5 times its body length, at speeds of 26 body lengths per second. That works out to 13.4 miles per hour or 6 meters per second . The initial acceleration is enormous: 500 m s−2 or 51g. For comparison, the space shuttle launches at 3g and humans pass out at accelerations approaching 10g. It takes less than a tenth of a second for the chameleon to snag its prey!

    Corkscrew Collagen: This impressive performance exceeds the capability of any muscle in biology by an order of magnitude. So what’s the secret behind the ballistics? The chameleon’s tongue has energy stored in concentric layers of a springy fiber, called collagen, wrapped around a stiff cartilage core. The powerful tongue muscle initially primes the spring by compressing it, to the same effect as a bow being pulled taut. When the tongue is launched, the spring uncoils explosively, slipping off the cartilage core. Once the sticky end snares the prey, the muscles work more slowly to reel it back in. This gives chameleons a competitive edge over lizards and other reptiles. Watch ▶ http://goo.gl/EBFty

    Breakfast at Dawn: Another advantage to this strategy is that the chameleon can catch its prey even at chilly temperatures when its muscles slow down drastically: unlike birds and mammals, reptiles are cold blooded and at the mercy of their ambient temperature. Watch how only the retraction of the tongue is slowed at low temperatures ▶ http://goo.gl/gT2hd

    REF ▶ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1691657/

    Slo Mo ▶ http://vimeo.com/12068409

    H/T to +Panah Rad for the gif ▶ http://i.imgur.com/XCytc.gif

    #ScienceSunday  
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  • Rajini Rao2014-02-23 15:02:03
    Dance of the Peacock Spider

    Doing the Y: Only 4 mm in size, the Australian male peacock spider (Maratus volans) puts on an impressive courtship display, rivaling the Village People in Peacock Spider Dances to YMCA . Described by researchers as multi-modal, the dance includes 3rd leg waves, synchronized unfurling of colorful belly flaps, abdominal bobbing and pedipalp flickers. As if these visual displays were not enough, the spider generates bursts of vibrations carried through the ground to signal his passion for his lady love. 

    Darwin's Dilemma: Is there an selective advantage to such complexity? How did it evolve? As the rituals get more elaborate, there may be diminishing returns given the limitations of biological cost and sensory perception. Translation: is it a waste of time? :) But studies show that redundant signals allow our spidery suitor to adapt to varied environments. Too dark to see the colorful fans? The seismic display compensates for lack of light.It is thought that each signal carries a different message for the female to evaluate. It's also an exercise in self preservation: males risk falling prey to the cannibalistic tendency of the female spider. Web building male spiders generate shudder vibrations that measurably calm the female's aggression. Others present a silk-wrapped nuptial gift that distracts the female long enough to get the deed done. An unusual tactic called thanatosis is to is to feign death when the female shows signs of terminating the romantic act. Once the female has dragged off the motionless male, she begins to feed on his nuptial gift upon which the male quickly revives to resume mating!

    So humans, do you see any parallels in strategy? Perhaps, you too met your mate on the web?

    ▶Nuptial gifts: http://goo.gl/VCsbzN
    ▶Spider Shudders: Male courtship vibrations delay predatory behaviour in female spiders. Wignall and Herberstein (2013) http://goo.gl/wT29bD
    ▶Dance Moves: Multi-Modal Courtship in the Peacock Spider, Maratus volans. Girard et al. (2011) http://goo.gl/SlIK1E
    ▶Gifs: via http://biomorphosis.tumblr.com/

    #ScienceSunday  
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  • Rajini Rao2012-01-08 19:28:22
    Walking Heads: Kinesin or The Little Engine That Could :)
    Have you wondered how things (like vesicles and mitochondria) move about inside a cell? They don’t just drift aimlessly through the thick cytoplasmic soup-rather they are ferried by kinesin, a hard working molecular motor.

    To watch mitochondria motor down an invisible highway inside a nerve cell see: Mitochondrial Moving in an Axon.mov

    The kinesin highway is made of microtubules : a bundle of 13 filaments that have distinct ends (known as + and – ends). Kinesins move cargo towards the + end (from the center of the cell to the periphery) and dyneins move them in the opposite direction. Watch what happens when fluorescent microtubules are placed on a slide coated with kinesin! Kinesin-1 gliding motility assay, whole casein passivation.avi

    Cargo is tethered to kinesin by a long coil. The two heads of the motor walk along the microtubule in a hand-over-hand mechanism using ATP hydrolysis as a power source. Each ATP moves the motor one 8 nanometer step. Notice that kinesin is a processive motor: once it is attached to the microtubule it takes (on average)100 steps, before it lets go.

    For a narrated 2 min mechanism see:Kinesin Walking Narrated Version for Garland

    Many, many thanks to +Kevin Staff for being such a sport and converting the kinesin video into an animated gif! Special shout out to +Andreas Schou who requested some ‘kinesin love’ and to +Henry K.O. Norman who is working on an animated production on cellular mechanisms.

    For #ScienceSunday curated by +Allison Sekuler and +Robby Bowles .
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  • Rajini Rao2013-08-18 19:35:31
    Rattler!  Did you know that the western diamondback rattlesnake Crotalus atrox can rattle its tail continuously for hours at frequencies approaching 90 Hz (90 times per sec)? This is twice as fast as a hummingbird's wings

    Nailing the Noise: The tail-end of the rattlesnake has a series of hollow "buttons" linked together, each made of keratin (found in our nails) and modified from the snake's scales. At birth, there is only one pre-button, but each time a snake sheds its skin, another button emerges at the end. It's a myth that one can tell the age of a rattlesnake from the number of buttons, because a snake may molt variably in a year and the buttons do break off with use.  

    Sound production in animals, is energetically expensive. But the rattler is an evolutionary marvel, optimized for minimal cost and maximal efficiency (for the aficionados, only 0.015 micromoles ATP consumed per gram muscle per twitch). Surprisingly, energy use is independent of temperature and rate of rattling. There are six sets of tailshaker muscles, arranged at 45 degree angles to the axis of the tail. All six are active during rattling, with muscles on one side contracting while those on the other side relax. This out of phase contraction generates an oscillating motion seen in the gif image

    Once you've heard a live rattler, you'll never forget it, says +Gnotic Pasta, who has plenty of snake stories to share. Do you have any cool facts or anecdotes about rattlers? Also check out +Buddhini Samarasinghe scary post on Bite Reflex of a Snake here: http://goo.gl/Lz7oBN

    ▶ BBC Video (3:50 min) on high speed filming of the rattle (look behind the rattle for the forked tongue darting out!): Slow motion rattlesnake - Slo Mo #3 - Earth Unplugged

    ▶ Great basin rattlesnake Crotalus viridis lutosus filmed by our intrepid G plusser +Gnotic Pasta  :  http://vimeo.com/64675533

    ▶ REF (old, but free): Structural correlates of speed and endurance in skeletal muscle: the rattlesnake tailshaker muscle. Schaeffer et al. http://jeb.biologists.org/content/199/2/351.long

    H/T to +Amy Robinson  for sharing the gif that inspired this post (http://goo.gl/pzi4Yv). 

    #ScienceSunday  
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  • Rajini Rao2014-02-04 23:00:11
    ///\oo/\\\ Tarantula!

    ▶ All arthropods (insects, spiders and crabs) have a hard exoskeleton, which they must shed at intervals, to catch up on their growth. Known as ecdysis (from the Greek ekduo to strip off), the process is carefully coordinated, risky in the wild, and fraught with difficulties.

    ▶ For several days or even weeks before the molt, a tarantula will appear moody and sluggish, refusing to eat. It spins a cradle, called molting web (seen to the left of the gif), and lays on its back. Its heart rate increases dramatically and hemolymph ("blood") is pumped into the upper body (cephalothorax) so it nearly doubles in size. The pressure cracks the carapace along the sides and front. Wave like muscle contractions in the abdomen push the old exoskeleton, lifting it off like the lid of a can. Now comes the tricky part: the spider must work its legs out of the old shell, with forward facing hairs and bristles keeping it from slipping back inside. 

    One well-placed kick, and the ordeal is over - here, have a cigar! 

    ♺▶ Fun Facts (aka everything you wanted to know about molting but were afraid to ask):

    ● Before the molt, the spider secretes a digesting fluid that loosens and eats away at the old cuticle (yum!).

    ● While spiderlings molt several times a year, mature females, who can live up to 40 years molt every other year. Unfortunately, many males do not survive their last adult molt, because their male sex organs get stuck in the exoskeleton (sorry, guys!). 

    ● The molt lasts from ~20 minutes, in babies, to several days in the adult (ladies, you sympathize, right?). 

    ● During a molt, spiders also shed their fangs, chelicerae (which they use for grasping), their throats and stomach lining, female genital organs (omg!), and the lining of their "book lungs". 

    ● A spider that has lost a leg can regenerate one during a molt.  

    Credit: This has been a fun Google+   #collaboration  with the lovely +Carmelyne Thompson  for   #ScienceEveryday . Carmelyne gif-ed the ecdysis time-lapse for this post, after we discussed another cool spider molt gif on her post (http://goo.gl/fVo5fp). If you don't have Carmelyne in your circles for more science fun, you should! 

    More reading: http://goo.gl/U6w0cV
  • 317 plusses - 134 comments - 269 shares | Read in G+
  • Rajini Rao2012-11-29 02:49:31
    Chemis-Tea

    The Science of Tea: For 4,700 years, this infusion from the tender leaves of Camellia sinensis has been delivering a cupful of healthy antioxidants and good cheer. Did you know that tea is the most widely consumed beverage, after water? To celebrate the birthday of +Siromi Samarasinghe , who has a PhD in tea chemistry, here is some chemis-tea.

    •  Caffeine : Did you know that weight for weight, dry tea has more caffeine than coffee? But because more coffee is used per cup than tea, brewed tea has significantly less caffeine (~90 mg/250 ml).

    L-Theanine: A rare amino acid (γ-glutamylethylamide), found almost exclusively in tea, it has a calming effect on the brain. Theanine suppresses the stimulation by caffeine of brain excitability, reduces blood pressure and protects against neuronal cell death.  It is a structural analog of glutamine, which is a byproduct of glutamate, the main excitatory neurotransmitter in the brain. Theanine inhibits the transport of glutamine and dampens neurotransmission.

    Catechins: Up to 30% of dry weight in tea, catechins are a type of antioxidant also found in chocolate and wine (Mmm..). Catechins are classified as flavonoids and have been shown to reduce the risk of stroke and cancer.

    There are many other antioxidants and polyphenols found in tea. Tea is best drunk in company, but if you are alone, you can still have a tea party:

    I had a little tea party
    This afternoon at three.
    'Twas very small-
    Three guest in all-
    Just I, myself and me.

    Myself ate all the sandwiches,
    While I drank up the tea;
    'Twas also I who ate the pie
    And passed the cake to me.
    -Jessica Nelson North

    Image: http://goo.gl/fRk6V

    #happybirthdaysiromi #ScienceEveryday  
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  • Rajini Rao2013-01-27 15:51:48
    Ode to Mitosis

    Mitosis is a process
    For One cell to become Two
    There are Four distinct phases
    Happening within You

    First comes Prophase
    The Chromatin strands condense
    They now become visible
    Through a microscope lens

    Next comes Metaphase
    The important Stage Two
    Chromosomes attach to Spindle Fiber
    Using Molecular Glue

    Then comes Anaphase
    It's really quite sad
    Sister Chromatids separate
    To opposite poles- too bad :(

    Finally, it's Telophase
    Nuclear membranes reform
    Spindle fibers disperse
    And Two new cells are born.

    Poem: Playfully plagiarized, willfully altered and spell-checked from the original "reallygoodpoetry" at http://goo.gl/OVTvb

    Images: Gifs from http://infinity-imagined.tumblr.com/page/4
    Watch original movie here: http://goo.gl/7HjG7

    #ScienceSunday  
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  • Rajini Rao2013-11-28 15:41:56
    Turkey and Tryptophan: Thanksgiving Myth Debunked

    ƵƵƶƶ Why do we feel sleepy after a big meal? You've probably blamed the Thanksgiving turkey for having too much tryptophan, an amino acid that the body converts to serotonin and melatonin, two sleep-inducing compounds. But it turns out that tryptophan has to be consumed on an empty stomach and not with gourmandish excess of cranberry sauce and pumpkin pie, to be effectively blamed for your soporific state.  Did you know that even oat bran and soybeans contain more tryptophan than turkey? Check out this infographic ▶ http://goo.gl/pQtLTp .

    ƵƵƶƶ Another popular theory is that after a big meal, our body diverts blood supply to the gut, and away from the brain, to help digestion. While this seems logical, it turns out that cerebral blood flow and oxygenation are kept stable through autoregulation mechanisms even when blood flow to the gut or muscles increase after a meal or during exercise.  Blood vessels in the brain expand or contract in response to changes in blood pressure to keep flow constant. Another myth debunked! 

    ƵƵƶƶ The most likely culprits are gut-brain hormones that regulate both feeding and sleep. Orexin is one such example: it promotes hunger and alertness, but is inhibited by gastric distention and satiety. The ability of hunger to promote alertness is thought to be an evolutionary adaptation that keeps us motivated to search for food. Interestingly, mutations in orexin were recently linked to narcolepsy, a pathological form of sleepiness. Finally, it has been argued that sleep allows for "cognitive reinforcement" of the circumstances that led to your energy acquisition, an important survival skill! So when postprandial somnolence hits you after your big Thanksgiving meal, you're actually learning an age-old survival mechanism :) 

    Ref: http://www.ncbi.nlm.nih.gov/pubmed/15488646

    Gif: Via http://www.reactiongifs.com/tag/sleepy/

    #ScienceEveryday   #HappyThanksgiving  
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  • Rajini Rao2012-03-10 01:40:28
    Feel Good Friday: 8 am on March 5, 2012. Idyllic blue ocean and ripples of surf. Suddenly, a pod of dolphins appear and beach themselves on this Brazilian coast. Watch the amazingly efficient rescue.
  • 261 plusses - 91 comments - 264 shares | Read in G+
  • Rajini Rao2013-04-14 12:56:49
    Toxoplasma: Cats, Rats and Mind Hacks

    Bizarre and Beautiful: More than a third of the world's population is infected with the parasite Toxoplasma gondii. We pick it up from uncooked meat or from changing a cat's litter box. Although apparently harmless to healthy adults, "Toxo" is dangerous to the human fetus and to immuno-compromised people. This is why pregnant women and people with vulnerable immune systems are advised to avoid cats.

    Mind Control: The parasite infects the limbic areas of the brain near the fear and sexual attraction regions. Because it carries a gene that codes for an enzyme crucial in dopamine production, it can alter levels of this neurotransmitter. Infected rats become oddly fearless of cats but not of anything else, making it likely that they end up in a cat's intestine, the only place where the parasite can reproduce! They also make more testosterone and mate more, ensuring the spread of the parasite to other rats. The ability of parasites to manipulate host behavior for their own benefit is extremely rare in mammals because our blood brain barrier is so effective in keeping most pathogens out. But not this one.

    Why Cats Rule the Internetz: If this parasite can profoundly affect rats, what about people? Studies have shown that infected men have altered behavior and personality including a tendency to disregard rules, higher suspiciousness and jealousy. Schizophrenics are more likely to be infected with Toxoplasma, and there are disturbing links to suicide as well. A 2006 study published in the journal Proceedings of the Royal Society B found that antipsychotic drugs, commonly used to treat schizophrenia, reverse the fearlessness effects of T. gondii in the brain. This is why the CDC classifies toxoplasmosis as a neglected parasitic disease

    Image: A rosette of Toxoplasma gondii cells by Markus Meissner (University of Glasgow, UK) from Nature Methods http://goo.gl/E825h

    Facts: http://www.cdc.gov/parasites/toxoplasmosis/

    #ScienceSunday  
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  • Rajini Rao2013-09-01 13:33:54
    The Beat Goes On 

    The Cardiomyocyte: Your heart beats about 72 times per minute, or 100,000 times a day, clocking an average of 2.5 billion times in a lifetime and working harder than any other muscle in your body. After all, it has to pump some 2000 gallons of blood around 60 miles of blood vessels each day. No matter how hard you train, the skeletal muscles of your arms or legs could never keep this up. So spare some love for the cardiac muscle cell, or cardiomyocyte

    The Pacemaker: The heart marches to its own tune, unlike the skeletal muscle which gets direct input from a motor nerve. Indeed, the heart would be an unwieldy mess if each individual fiber needed a motor nerve connection.  Instead, every beat of the heart starts within the sinoatrial node (SAN) containing <10,000 pacemaker cells equipped with a built-in clockwork mechanism to fire rhythmically. These electrical impulses spread through the muscle fibers by direct communication from cell to cell via  special channels called gap junctions, that synchronize the contraction. If the pacemaker fails, the ~5 billion working cardiomyocytes don't get their marching orders and the heart slows down or becomes arrhythmic. Promising new research aims to convert ordinary cardiomyocytes to pacemaker cells by expressing a master regulator gene, Tbx18 to replace those lost by disease or defects.

    Sparks and Stripes: Each cardiomyocyte is packed with ordered arrays of thin and thick filaments that slide past each other to make the muscle contract. The thin filaments are made of actin seen as red stripes in the image. The thick filaments are an assembly line of myosin motors that use a rowing motion to pull on the actin filaments. In the absence of an electrical signal, the muscle is relaxed, with the filaments kept apart by a guardian protein called troponin C. The magical molecule that sets the contraction in motion is calcium, seen in the gif as sparks and waves. Each electrical impulse releases a packet of calcium that binds to troponin C, and moves it out of the way to trigger contraction. But the calcium is quickly captured (by calcium pumps and exchangers) and moved back into stores, so the muscle relaxes..before it all begins again.  

    Another installment in the   #excyting series on cell types.
    Adipocyte: http://goo.gl/S4fQFS
    Erythrocyte: http://goo.gl/R5R6Y0
    Astroycte: http://goo.gl/SMpXMV

    REF: Direct conversion of quiescent cardiomyocytes to pacemaker cells by expression of Tbx18. Kapoor et al., 2013 http://www.nature.com/nbt/journal/v31/n1/full/nbt.2465.html

    IMAGE: Composite put together by +Kevin Staff from http://goo.gl/r8wpX8 and  http://goo.gl/1aWsYk . Thanks, Kevin!

    SONNY & CHER "THE BEAT GOES ON" (1967) ORIGINAL RECORDING

    #ScienceSunday  
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  • Rajini Rao2012-02-17 02:06:02
    Happy Birthday, Ernst Haeckel! German biologist and artist, Haeckel (1834-1919) left his mark in thousands of beautiful, accurate and intricate drawings of life forms at a time before microscopes could take pictures. Did you know that he coined many terms that we take for granted today including ecology , phylum , stem cell and Protista? He is even credited for the first use of the phrase "First World War" to describe the "Great European War" in 1914.

    Flamboyant and passionate, Haeckel was both spectacularly right and completely wrong! He sent his students to Indonesia to look for the remains of ancient humans, resulting in the first human fossil of Pithecanthropus (Homo erectus). He also believed that ontogeny recapitulates phylogeny: that embryos go through stages in development where they resemble lower orders of life. Although junior looked a bit like a fish at one time, but not literally, right? ;)

    Read more about this fascinating scientist: http://en.wikipedia.org/wiki/Ernst_Haeckel
  • 344 plusses - 83 comments - 181 shares | Read in G+
  • Rajini Rao2013-01-06 17:18:27
    The Genetics of Autism

    Contrary to popular belief (and Jenny McCarthy), autism is the most genetic and inheritable of all neurodevelopmental disorders. Identical twins have >80% chance of shared diagnosis, versus a much lower ~10% chance in fraternal twins, a classic indication of underlying common genetic cause. 

    What is autism? Classical autism is part of a broader group of autism spectrum disorders (ASD) characterized by (i) impaired social communication and interaction, (ii) absence or delay in language and (iii) restricted, repetitive behavior. These features vary hugely, from severe intellectual disability to mild personality traits. Intellectual delays occur in 30-60%, and 30% also suffer seizures. Current rates of diagnosis are 1 in 88 children. This is partly due to a broadening of the diagnosis but could also reflect impact of changing environment on genetic susceptibility. 

    Monogenic cases of autism are known as syndromes. About 10% of children diagnosed with ASD have mutations in a single gene. The most common is Fragile X syndrome (FXS), which accounts for 5% of autism cases with as many as 50% of individuals with FXS meeting criteria for autistic disorder. Other syndromes that present with ASD are Tuberous Sclerosis, Retts, and Neurofibromatosis. Although the primary diagnosis is not ASD, the symptoms include ASD. 

    Polygenic disorders are caused by additive effects of multiple genes. Because inheritance patterns of autism are not Mendelian, it was initially thought to be polygenic, like traits of hypertension, height or skin color. Austism superficially fits this definition because of the continuous spectrum of characteristics. But, it’s a lot more complex because no single gene appears to account for more than 1% of the non-syndromic cases. 

    Heterogenic disorders occur when mutations at any of a number of different genes can give rise to the same phenotype. In autism, many of the mutations are unique, rare and arise de novo, not being found in parents or recent ancestry. Most mutations occur on only one allele (one of two copies of the gene). Many are copy number variations, affecting gene dosage, caused by insertions and deletions in the chromosome. The emerging theory is that many different mutations converge on a common function: synaptic transmission

    The synapse: Information transfer occurs at the synapse or junction between neurons. The first synapses in human cortex appear 40 days after conception. The most dramatic change takes place around birth. During the first three years of life, more synaptic contacts are formed, but only some will be stabilized. Many genes implicated in autism (image) function at the synapse, and the timing of appearance of autistic characteristics coincides with synapse maturation.

    REF: Autism and Brain Development. Walsh et al., Cell (free read) http://goo.gl/hkbsC

    #ScienceSunday  
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  • Rajini Rao2013-01-14 23:50:29
    Panspermia: Hoax or Hope?

    Fire in the Sky: On December 29, 2012 a fireball exploded in the skies above Sri Lanka, followed by a meteorite that fell near the ancient city of Polonnaruwa. A sample was sent to the Buckingham Institute of Astrobiology and Cardiff University. Researchers now report in the Journal of Cosmology of finding fossils of diatoms enmeshed within the meteorite. Because of the way the microfossils were distributed within the rock, they rule out surface contamination.

    Panspermia (from the Greek "all" and "sperm") is the idea that life exists throughout the Universe, distributed by meteoroids, asteroids and planetoids. So, is this compelling evidence of Panspermia or life in outer space?

    Red Rain: The researchers claim that the mysterious red rain that fell in the area within days of the meteorite, reported by our own +Siromi Samarasinghe (http://goo.gl/dq7Jq), was seeded from the meteorite. Reports of red rain were first made in Homer's Iliad and may simply be from airborne algal spores. Is this red rain a red herring?

    Earthly Origin? Could it be that this rock was initially blasted off from earth, by the Mesozoic-ending impact on the Yucatan Peninsula, and is now falling back to earth after a grand journey? The article does mention that similar fossils have been found that date back to the time of the dinosaurs.

    Hasty Science? The meteorite only just landed, less than 3 weeks ago! How much of a review did this paper get? The authors make the grand statement that "identification of fossilised diatoms in the Polonnaruwa meteorite is firmly established and unimpeachable" and with several self-citations, that "the idea of microbial life carried within comets and the theory of cometary panspermia is thus vindicated". Their final sentence is a WIN, in my opinion: The universe, not humans, must have the final say to declare what the world is really like. What do you think?

    Reference (with pictures!): http://www.buckingham.ac.uk/wp-content/uploads/2011/09/Polonnaruwa-meteorite.pdf

    #ScienceEveryday  
  • 353 plusses - 198 comments - 114 shares | Read in G+
  • Rajini Rao2012-08-24 11:21:20
    One Gif to Rule Them All: From Amphipod to Diatom to Bacterium. Captured in this amazing image is an electron microscope scan that zooms in on a tiny bacterium perched upon a diatom, lodged near the leg of an amphipod (a type of crustacean). Watch the scale at bottom right, go all the way from a millimeter, through the range of micrometers, down to 500 nanometers!

    I was reminded of the verse by Jonathan Swift (1733):
    "So nat'ralists observe, a flea
    Hath smaller fleas that on him prey,
    And these have smaller fleas that bite 'em,
    And so proceed ad infinitum ."

    Image Credit: "Fractal Cosmos" by James Tyrwhitt-Drake at the University of Victoria.
    Stunning images of Diatoms: http://goo.gl/smk3w

    #scienceeveryday +ScienceSunday 
  • 186 plusses - 49 comments - 265 shares | Read in G+
  • Rajini Rao2013-10-13 13:48:40
    Fiddle-de-dee: The male fiddler crab is a fine example of how evolutionary pressure can select an exaggerated physical trait: while one claw is small and used for feeding, the other is grossly enlarged, reaching up to 2/3 of his body weight! The female has symmetrical, small claws. So, does size matter? 

    Ornament vs. Armament: The large claw of the male fiddler crab is a sexual ornament, like the feathers of a peacock. With it, he waves flirtatiously at the susceptible female, enticing her to his sand burrow. The larger and more conspicuous his claw, the greater his chance at mating success. It is also an effective weapon, used to threaten and wage battles with competing males. But these are competing demands: large and light claws may be waved at lower energy costs, whereas heavy claws with powerful muscles are better in fights. Studies show that claws evolved to optimize fitness in both mating and fighting (REF: http://goo.gl/n00sZa)

    Keeping Up Appearances: In a study performed upon a beach in Zanzibar, Tanzania, scientists tethered a female crab by super-glueing a thread to her carapace and anchoring it to a spike in the sand. If she was viewed by a solo male, a friendly waving at a leisurely pace of 11.5 waves/min ensued. But in the presence of male competition, his waving became more urgent, at 16.5 waves/min! (REF: http://goo.gl/ME1wW5). Watch this little guy seemingly inspired by the Village People :) YMCA crab dance with music

    Honesty is Not the Best Policy: When a male fiddler loses his major claw, he regenerates a new one of similar size but much weaker fighting ability. Studies have shown that the male can bluff his way through fights with the weaker claw, in a form of dishonest signaling. This unfair advantage presumably makes up for the costs of claw regeneration. (REF: http://goo.gl/OQNfB7)

    A Cool Tool: If you think you now know all there is about the fiddler crab claw, consider this. Scientists measured body temperature of fiddler crabs subjected to a heat lamp and showed that the large claw actually acts as a heat sink, allowing the male to cool off more quickly with it. On a hot beach, this advantage may help offset the high energy costs of his exaggerated "male ornament". (REF: http://goo.gl/EpxrUq )

    ✤ GIF:  http://headlikeanorange.tumblr.com/post/49121046623

    #ScienceSunday      #HappyBirthdayHalfPintBuddy 
    Birthday shout-out to +Buddhini Samarasinghe !
  • 348 plusses - 77 comments - 131 shares | Read in G+
  • Rajini Rao2013-06-08 13:13:15
    A Vaccine for Addiction: For the 1.9 million cocaine users in the US alone, addiction is a problem for which no FDA-approved therapy exists. Now, a vaccine effective on primates is ready for human trials.

    ● Cocaine blocks the recycling of dopamine so that it accumulates in the brain, prolonging and amplifying signaling in reward centers to generate that pleasurable "high". Over time, dopamine receptors (pink buckets in image) decrease, requiring higher doses of cocaine and causing a vicious cycle of dependence. There are drugs that interfere with cocaine's action but they alter these important signaling pathways and have side effects.

    The Cocaine Vaccine  triggers an immune response to the drug, that "eats up the cocaine in the blood like a little Pac-Man before it can reach the brain,” says Dr. Ronald G. Crystal, of Weill Cornell Medical College.  The trick is to chemically link a cocaine analog to the common cold virus so that the body is tricked into making antibodies. The virus is crippled and cannot cause an infection. To feel the drug high that cocaine users seek to achieve, at least 47 percent of the dopamine transporter needs to be occupied by cocaine. The vaccine reduces this occupancy to 20% so the user fails to achieve the cocaine high.

    Story: http://rt.com/usa/cocaine-vaccine-drug-pacman-219/
    Free PubMedCentral Read: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3048190/

    Image: Left, Mechanism of Cocaine at the Synapse (http://goo.gl/ZCk4K), Right, Effect of anti-cocaine vaccine on non-human primate brain, taken from Maoz et al., Neuropsychopharmacology. 2013 May 10. doi: 10.1038/npp.2013.114. Epub ahead of print)

    #ScienceSunday  
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  • Rajini Rao2013-01-12 19:00:45
    Gluten Be Gone: Synthetic Biology Solution for Celiac Disease

    What is Celiac Disease? Celiac disease or gluten allergy comes from eating wheat, rye or barley. Most common in people of N. European descent, the symptoms include diarrhea, weight loss and an increased risk of cancer. 

    Why is gluten allergenic? Gluten contains an unusual protein called alpha gliadin, which has many repeats of the amino acids Proline and Glutamine (PQ motifs) that are resistant to the digestive enzymes in our stomach. In some people, these PQ-rich fragments cause severe allergy and inflammation.  

    Clinical trials: A natural bacterial enzyme from Sphingomonas capsulata that can break down PQ motifs is in clinical trials as an Oral Enzyme Therapeutic. But it works poorly in the acidic compartment of our stomach, and attempts to engineer it to become acid tolerant have not worked. 

    Trial by Acid: Univ. Washington undergraduates tackled the problem from the opposite direction. They found an enzyme called Kumamolysin-AS in a heat and acid loving bacterium Alicyclobacillus sendaiensis that was already acid tolerant. They tinkered with it, using the Fold-It protein folding game, until they found variants predicted to change the enzyme’s preference from Proline Arginine (PR) to Proline Glutamine (PQ). When they made and tested ~260 engineered enzymes, they found one that had a 116-fold increase in ability to digest the gluten peptide in acidic conditions, with a switch in preference of 800-fold! The new enzyme, KumaMAX, could be used in oral therapy or engineered into common bacteria found in yogurt to make probiotics.

    So Much Win!: This work (1) could help millions of gluten allergy sufferers world wide, (2) was done by undergraduates competing in iGEM, an annual synthetic biology competition originally founded at MIT, (3) using gaming software, (4) built on basic research done on an obscure bacterial enzyme, and (5) published with student authors in a peer-reviewed journal. 

    Images: Normal catalytic triad of protease enyzmes (left) and acid tolerant substitution (right) found in bacteria growing in acid, hot springs (middle).

    Paper: Computational Design of an α‑Gliadin Peptidase; Gordon et al., (2012) JACS 134, 20513−20520

    Team UW iGEMhttp://goo.gl/vgvTX

    #ScienceSunday   #syntheticbiology   
  • 180 plusses - 147 comments - 164 shares | Read in G+
  • Rajini Rao2012-12-13 18:32:22
    Precious Purses:  Who is the Artist?

    Caddisflies are common insects of the order Trichopterae resembling butterflies. The larvae build protective tubes held together with silk, often incorporating grains of sand, bits of shell and twigs from their aquatic environment. Artist Hubert Duprat wondered what would happen if he upgraded their raw material with gold shavings, pearls and turquoise. The larvae obliged by creating beautiful art!

    ☼ In this collaborative project between the insects and the artist, the lines between the craftsman and the creator are blurred. Is the insect the true artist, or merely the executer of Duprat's creative expression? 

    #ScienceEveryday   
    Watch: Caddis Fly Larva Art More: http://www.cabinetmagazine.org/issues/25/duprat.php
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  • Rajini Rao2012-12-18 14:23:12
    Give Me a Hand

    ☼ A quadriplegic woman, paralyzed from the neck down from a neurodegenerative disorder, was able to feed herself chocolate and give high-fives thanks to the most sophisticated prosthetic arm yet, with 7 degrees of freedom. Within the second day of training, she was able to perform basic tasks, with a 92% success rate of controlling the robotic arm. This study is the first to demonstrate feasibility of human brain implants to control an external device .

    Brain-Machine Interfaces convert brain signals into movement. The researchers first mapped the signals generated in the patient's brain when she thought of moving her arm and programmed the response of the prosthetic arm accordingly. Two small computer 4mm chips were implanted into the patient’s left motor cortex. The chips were 96 channel microchips designed to detect and record small electrical potentials that motor cortex brain cells produce when executing a movement. "The result is a prosthetic hand, which can be moved far more accurately and naturalistically than previous efforts."

    Future Scenarios include tactile feedback using sensors to feed into the patient's sensory cortex, wireless communication, and possibly activation of the patient's own muscles with implants.

    Story and Videohttp://www.livescience.com/25600-quadriplegic-mind-controlled-prosthetic.html

    Original paperhttp://extremelongevity.net/wp-content/uploads/brain-machine1.pdf

    #ScienceEveryday  
  • 220 plusses - 74 comments - 159 shares | Read in G+
  • Rajini Rao2013-10-20 11:56:53
    How Hearing Happens

    The Hair Cell: When a young student heard that the lab next to mine studied frog hair cells, she exclaimed, "Oh? I didn't know frogs had hair!" Actually, hair cells, so named because of the curious stacked arrangement of hair-like stereocilia emerging from their crowns (image a), are the cells that detect sound.  About 16,000 of them line the snail shaped cochlea of our inner ear, picking up sound induced vibrations of the fluid inside our ears of less than 1 nanometer. The remarkable hair cell is what gives us humans the ability to detect sound of frequency ranging from 20 Hz to 20 kHz. 

    Mechanosensation: How does a hair cell detect sound? The secret lies in the way the stereocilia are stacked. Each one is connected to an adjacent taller 'hair" by a tenuous thread, known as tip link (image b). At the bottom end, the tip link controls the opening of an ion channel while at the upper end it is held taut by a motor protein (myosin) that moves along tracks (actin) inside the "hair". When a mechanical disturbance in the surrounding fluid pushes against the hair bundle (image c), the tip link is stretched, yanking open the gate of the ion channel. Calcium ions flood the interior, changing the electrical potential of the cell and triggering a message to the nerves leading away from the cell. Immediately, however, the motor protein slips down, releasing the tension on the tip link and closing the ion channel to end the signal (image d).  Later, the motor protein climbs up the cables again to re-establish tension in the tip link. 

    Deafness, Eugenics and Alexander Bell: It may come as a surprise that the inventor of the telephone also had a profound impact on deaf culture. With both his mother and wife deaf, Alexander Bell became an avid proponent of "oralism" - teaching deaf people to articulate sounds in place of sign language. Given the uniqueness of deaf culture with frequent intermarriage among deaf people, Bell cautioned that the incidence of deafness could rise until there was a separate race of deaf people. Although his ideas on eugenics are not credited now, he was responsible for many changes made to education of the deaf. Deafness is the most common inherited sensory defect at 1-3 births per 1000. Interestingly, the most common inherited form of deafness has actually increased due to assortive mating (this is also seen in other disorders linked to ethnicity or race). Bell's goals may yet be achieved, not by eugenics but by cochlear implants, which may restore hearing and abolish deaf culture in the future. Will that be a good thing?

    Another installment in the    #excyting series on cell types.
    ▶ Cardiomyocyte: http://goo.gl/uBL37G
    ▶ Adipocyte: http://goo.gl/S4fQFS
    ▶ Erythrocyte: http://goo.gl/R5R6Y0
    ▶ Astrocyte: http://goo.gl/SMpXMV

    Image and Free Read: Corey, D. (2009) Cell biology of mechanotransduction in inner-ear hair cells. 
    http://f1000.com/prime/reports/b/1/58

    Through Deaf Eyes (Alexander Bell): http://goo.gl/DY2ouS

    #ScienceSunday  
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  • Rajini Rao2012-03-14 12:39:40
    Got any good Pi jokes? Here are a few of my favorites :)
  • 131 plusses - 51 comments - 223 shares | Read in G+
  • Rajini Rao2013-07-25 23:25:32
    The Appendix: Don't close the book on it yet!

    ● The vermiform appendix is the poster child of vestigial organs leading to the joke that, "Its major importance would appear to be financial support of the surgical profession." Like the wings of an ostrich or the eyes of the blind cave-dwelling catfish, the appendix no longer supports the function that it was designed to do: digest tough cell walls of plants. In herbivores, this function resides in the caecum, an off shoot of the large intestine, that houses symbiotic bacteria, producing enzymes (cellulases) by fermentation. Did you know that in the koala, the caecum is longer than the animal itself?! But, as Darwin noted, in hominids -apes and humans, the switch from a leafy to predominantly fruit diet made the caecum redundant and eventually, it degenerated into the finger-like appendix. Although we still eat plants, our vestigial organ does not house enough cellulase-secreting bacteria to digest more than a few grams of cellulose per day. 

    So why do we still have an appendix? It is notoriously prone to infection, commonly in children 8-13 years old. Before modern surgical methods, acute appendicitis was often fatal. What a poor design! But there is evidence that the appendix has useful functions. Like the tonsils, the appendix houses lymphoid tissue, or white cells, important for immunity. It has been compared to a "safe house", lodging beneficial bacteria that can repopulate our gut after an infection wipes out existing microbial flora. 

    ● A new study by a group at Duke University has concluded that the appendix has arisen independently more than 30 times in the evolution of mammals. By plotting diet on the evolutionary tree of mammals, researchers found that the appearance of the appendix did not correlate with a change away from herbivorous diets. Species with an appendix were scattered so widely on the evolutionary tree that they concluded that the appendix evolved separately along distinct branches. Also, they found that the larger the caecum, the larger the appendix: opposite to what one would expect for a vestigial remnant of the caecum. But naysayers argue, if it is so useful, why don't all mammals have an appendix? We'll have to wait until Science adds another Chapter to the Appendix! 

    Ref: Multiple independent appearances of the cecal appendix in mammalian evolution and an investigation of related ecological and anatomical factors. Smith et al. (2013) http://goo.gl/zJyviw

    Counterpoint: The vestigiality of the human vermiform appendix. A modern reappraisal. http://goo.gl/v9Qvm0

    #ScienceEveryday  
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  • Rajini Rao2012-09-15 15:41:47
    It’s Nasty: Thigmonasty (Greek thigma for touch and nastos for pressed close). Closure of the Venus flytrap (Dionaea muscipula), at 40-100 milliseconds, is one of the fastest movements in plant kingdom. Little surprise that it involves action potentials: electrical signals typical of nerve communication in animals. The trap is triggered when at least two of the tiny surface hairs are touched by an insect or spider within 20 seconds of each other. Since the movement costs energy, this coincidence of two stimuli safeguards against waste from accidental triggers.

    There’s no chemistry: Unlike chemical signals, like hormones, action potentials can fire within a millisecond and propagate rapidly over long distances. Although plants have the basic necessities for electrical signaling (ion channels, motor proteins), they have nowhere near the sophistication achieved in animals. Still, an action potential can achieve speeds of up to 40 m/s in plants and is used to respond to environment.

    Touch me: The first step is the opening of mechanically-sensitive ion channels that sense deformity of the hair. This causes the cell membranes to depolarize by reducing the distribution of charges across the cell. If this depolarization exceeds a certain threshold, additional chloride and potassium channels open to let in more ions. Movement of protons makes the cell wall acidic, allowing it to soften and let the cell elongate rapidly. Despite intensive study for ~130 years, the exact mechanism of signaling is not clear.

    Food fight: Recently, the digestive juice of the Venus flytrap was analyzed and found to closely resemble enzymes used in the fight against pathogens, rather than the digestive enzymes of animals. This suggests an evolution from defense pathways to food acquisition in carnivorous plants. Read more: http://www.asbmb.org/News.aspx?id=17935

    The Doors - Touch Me

    An early submission for #sciencesunday since I will be traveling tomorrow (Viva Barcelona!).
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  • Rajini Rao2013-09-22 16:55:25
    The Master Archer

    ▶ Lurking under the water surface in the estuaries and mangroves of India and Polynesia, the archer fish Toxotes (from the Greek Τοξοτης for archer) precisely aims a ballistic jet of water that knocks off a hapless insect from the shrubbery above, sending it tumbling into the water where it is promptly devoured. To dislodge prey anchored firmly to the vegetation with forces up to 10 times their body weight, the water jet must achieve a power of 3000 Watts/kg within a fraction of a second. Since this intrepid hunter was first described 250 years ago, scientists have puzzled over this mastery of archery.

    Fishy Physics: Biologists first considered a mechanism similar to the chameleon, where energy is stored in coils of collagen inside the tongue (explained in the Chameleon Catapult post http://goo.gl/B5fPVS). But dissection of the archer fish revealed no such specialized structure. Besides, they calculated that muscle power could maximally account for ~15% of the observed force of the water jet. Researchers then resorted to analysis of high speed video recordings of the archer fish in action. What they saw was a thin jet of water with a "head" that becomes increasingly bigger during flight. Surface tension and inertia hold the head together, pushing the tail jet into the head forming hammer-like pellet which strikes with deadly force. A fancy term for this is hydrodynamic amplification, and the physicists among you may enjoy reading about the "Ohnesorge number" and "Rayleigh-Plateu Instability" in the referenced paper. The rest of us will be intrigued by the similarity to Drop on Demand Inkjet Printing which similarly uses an explosively ejected drop of ink, as in Canon's Bubble Jet printer (http://en.wikipedia.org/wiki/Inkjet_printing). The archer fish achieves all this at a low evolutionary cost by gulping a small amount of air into a gun-barrel shaped groove in its mouth and closing its gills before delivery. Just like Diana the huntress amplified her muscle power with a bow, this little fish also exploits an external hydrodynamic lever to capture its prey.

    REF: Vailati et al. (2012)  PloS ONE; open access http://goo.gl/DHZ1C 

    H/T to +PJ Rosenberg for inspiring this post with the gif image he shared to the Science on Google+ community (http://goo.gl/fPDy2u).

    #ScienceSunday  
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  • Rajini Rao2013-10-27 13:39:28
    A Balancing Act

    Nature's Gyroscope: Your ear does much more than hear. While the snail shaped cochlea of the inner ear (pictured below) is superbly adapted for picking up sound vibrations (by deflections of hair cells described in last week's post), the rest of the inner ear is a complex labyrinth of tubes and chambers that keeps our lives in balance. 

    Up, Side and Down: Since we live in a three dimensional world, we have three fluid-filled semicircular canals arranged at right angles to each other, along the x, y and z planes. Each semicircular canal senses a different movement of our head: up and down, side to side, and tilt. When we move our head, the fluid inside the canal moves and presses on a tear shaped bulb at one end. The bulb (ampulla) has a collection of mechanically sensitive hair cells embedded in a jelly like matrix. Deflection of the "hairs" triggers a message to the balance center of our brain that is interpreted as a deflection of the head. Because we have a pair of ears, the deflections are mirror images so that when one side is stimulated the other is simultaneously inhibited by the movement.  

    Rolling Stones: Two other chambers sense horizontal and vertical accelerations of your body. The saccule detects changes in vertical movement (when you are in an elevator), and the utricle monitors horizontal movement (as when a car suddenly moves forward or stops). While these organs also have mechanically sensitive hair cells, what is different is a special overlaying membrane weighted down with tiny stones of calcium carbonate, around a protein core, called otoconia. A shearing effect of the membrane against the hair cells detects vertical and linear accelerations of your body.  Sometimes, the otoconia fall into one of the semicircular canals (see image) sending conflicting signals to the brain, resulting in vertigo. Fortunately, a series of head maneuvers can restore the rolling stones back into place. Ménière's Disease is a common cause of vertigo, accompanied by hearing loss and tinnitus. It is thought to be caused by disturbances in the fluid volume filling the inner ear. Future relief from vertigo may come from prosthetic devices, similar to a cochlear implant in the inner ear. See Physician Inventors Discuss First Device to Combat Vertigo

    Space Jellies: Did you know that NASA has been sending jelly fish out to space since the 90's for microgravity research? Jellies born in space have trouble orienting and swimming back on Earth because their gravity sensors, crystals of calcium sulfate much like our otoconia, fail to develop properly. Read more: http://goo.gl/Jtj00N

    A follow up on How Hearing Happens: http://goo.gl/lEHKjF

    #ScienceSunday  
  • 254 plusses - 81 comments - 125 shares | Read in G+
  • Rajini Rao2014-03-22 21:41:23
    Victorian Diatom Art

    In the mid to late 19th century, people became increasingly fascinated with science. Rising literacy led to a demand for books, and an anonymous book titled Vestiges of the Natural History of Creation became the rage (http://goo.gl/fYMl0m). Darwin proposed his theory of natural selection. Microscopes became cheap and readily available. They were used not only for scientific discovery, but also as tools for popular entertainment. Microscope clubs popped up and amateurs made their own slides. Clever entrepreneurs took advantage of the public's interest to make microscopic art by arranging hundreds or even thousands of tiny diatoms, butterfly scales or even beard hair (!) to generate these astonishing works of beauty. One such artist, Henry Dalton, used a boar hair and his own breath to move particles into position under a microscope. A newspaper article described him thus: "Although Dalton was dissipated, he excelled most of his imitators in this peculiar line of art" (http://goo.gl/tYPIUq).

    Source: Exhibition Mounts by Watson & Sons, London circa 1885. 
    http://www.victorianmicroscopeslides.com/slideexb.htm

    Reading: Antique microscopy slides reveal obsession with science http://goo.gl/c8a3d8

    #ScienceEveryday when it's not  #ScienceSunday  
  • 271 plusses - 59 comments - 123 shares | Read in G+
  • Rajini Rao2012-04-06 00:32:50
    Under the Electron Microscope. WOW! Can you guess what these everyday objects are?
    More: http://egotvonline.com/2012/03/13/25-everyday-objects-under-an-electron-microscope/
  • 177 plusses - 60 comments - 175 shares | Read in G+
  • Rajini Rao2013-11-29 19:55:22
    Petrichor: Smell of the Earth

    A heavenly scent: Do you love the smell of soil after a fresh bout of rain? Are you a fan of the earthy smell of beets? There is a word for that: petrichor.  It comes from the Greek petros, meaning stone and ichor, the fluid that flows in the veins of the gods. It is defined as "the distinctive scent which accompanies the first rain after a long warm dry spell". 

    Geosmin: After puzzling over the smell of soil for over a hundred years, scientists have pinned the source to Streptomyces, the soil bacterium that also gifts us with the most antibiotics. The bacteria release volatile compounds when disturbed, like the bicyclic alcohol, geosmin (named for "earthy smell"). Did you know that the human nose is incredibly sensitive to geosmin? We can detect as little as ten parts per trillion! 

    One hump or two?: Bactrian camels are reputed to detect water from 50 miles away. The signature smell of Streptomyces is easily carried across the desert and picked up by the camel's sensitive nose. In return, the bacterium probably benefits from having its spores spread around. The musty earth scent of some Cactus flowers is also due to a derivative of geosmin. It lures pollinating insects by a promise of water. This is known as floral mimicry. Unfortunately, fish that absorb minute amounts of geosmin from water don't taste that great.

    ✿ This smelly chemistry post is a birthday present for our favorite Google+ chemist +Siromi Samarasinghe! Check out other odoriferous posts in Sirome's honor by +Chad Haney (http://goo.gl/INUpXi , http://goo.gl/SN4WQs and http://goo.gl/XpVL9R). 

    Image: Streptomyces coelicolor http://microbewiki.kenyon.edu/index.php/Streptomyces

    Source and Ref: http://www.bios.niu.edu/meganathan/smell_of_soil.shtml

    #ScienceEveryday  
  • 272 plusses - 98 comments - 98 shares | Read in G+
  • Rajini Rao2013-05-12 12:19:00
    Roses are Red, Blood Cells Blue

    The heart is a symbol of love, and on this Mother's Day, let's consider the cardiovascular changes in a pregnant mother. As the sole provider of nourishment to the baby, the mother's cardiac output (blood volume) increases by 50% during pregnancy...that's an extra liter and half. Her heart will enlarge and beat faster, by about 15 beats/min. The growing fetus pushes her heart upwards and to the left. She will need more red blood cells to carry extra oxygen, although the increased numbers do not keep up with the blood volume. The higher requirement for iron and the dilution of red cells in blood can make mama-to-be tired and anemic.

    A pregnant woman is hypercoagulable: more likely to form clots. This is thought to be an evolutionary precaution against hemorrhaging after delivery, but it puts the mother at risk for dangerous embolisms. In scanning electron microscope images of blood smears from non-pregnant and pregnant women, clot-forming platelets were never associated with red cells in non-pregnant women (A) but invariably found attached to red cells through early (B) and late (C) pregnancy and 6-8 week postpartum (D). These platelets developed long processes (pseudopodia) that link the red cells together, making it easier to form clots.

    A Biologist's Mother's Day Song
    Just like two strands of DNA are spirally entwined
    Your nature and your nurture are inspiringly combined
    Scientists remind me and I find that it is true
    Slightly more than half of everything I am is thanks to you

    Image source ▶ http://goo.gl/QrFOV
    Pregnancy and Cardiovascular Changes ▶ http://goo.gl/Quj1t

    #ScienceSunday #MothersDay  
  • 283 plusses - 63 comments - 104 shares | Read in G+
  • Rajini Rao2013-06-22 20:46:48
    Viral Vectors Versus Viral Video: This video, going viral on G+, documents the case of a 7 year old girl with acute leukemia who was cured of her cancer last year, apparently by pitting one disease (cancer) with another (HIV-AIDS)! Breathless science enthusiasts are marveling at the justice of curing cancer with HIV!

    • Actually, HIV is simply being used as a "vector" or carrier for gene therapy because it naturally binds to receptors on the target cells, in this case, T cells. Researchers can use different viruses to target different cells by matching infectious viruses with their natural hosts. Of course, only the viral shell is used, with viral genes being replaced by the genes of choice; that is, the virus is crippled, and cannot cause disease (AIDS).

    • The idea is to introduce a gene ("chimeric antigen receptor") into immune T cells that would make them seek out and destroy the cancer cells. The T cells are removed from the patient, the gene is introduced into them via the modified HIV carrier, and then injected back into the patient. More recently, this method was used with heartwarming success on adults with leukemia for whom chemotherapy failed : http://goo.gl/7SWVN

    • Sensationalistic titles, such as Fighting Fire with Fire are misleading and unnecessary. The HIV carrier is the least interesting part of the story, in my opinion. T cell therapy is promising and newsworthy without the hype.

    Abstract: http://stm.sciencemag.org/content/5/177/177ra38
    #ScienceSunday  
  • 254 plusses - 59 comments - 123 shares | Read in G+
  • Rajini Rao2012-05-18 01:42:00
    Does a virus have color? Actually, no. Because viruses are smaller than the wavelength of light (400-700 nanometer), they hide within its waves and can only be seen with an electron microscope. Viruses range in size from 20-300 nm. Yet, most images of viruses are pseudocolored, either to visualize detail or for aesthetic appeal.

    • Glass artist Luke Jerram, who is color blind himself, works closely with virologists to create transparent jewel-like replicas of microbes 1,000,000 times their actual size. Virus shapes can be helical, icosahedral (12-sided), prolate (capped cylinder), enveloped or rounded.

    Check out his gallery online: http://www.lukejerram.com/glass/gallery

    #scienceeveryday #sciencesunday
  • 146 plusses - 108 comments - 166 shares | Read in G+
  • Rajini Rao2012-01-29 15:31:55
    The Glia Club. Neurons are flashy, but an estimated 90% of your brain is made up of glial cells! Derived from the Latin word for “glue”,glia hold your brain together, allowing neurons to communicate. For too long, glia have been dismissed as the domestic servants of the electrically elite neurons: feeding them, mopping up neurotransmitters in a synapse, and repairing injured or diseased neurons.

    • But it’s the variety and number of our glia that make our brain unique. Only vertebrates have special glial cells that wrap around nerve axons providing electrical insulation (seen as white matter in the brain), making transmission of action potentials 50-100 times faster!

    • A postmortem of Einstein’s brain revealed no clues to his genius from his neurons. Interestingly, he had disproportionately larger numbers of glial cells in his cerebral cortex, an area involved in complex reasoning,math and imagery. Astrocytes, a type of glial cell, have bushy processes that can make as many as 30,000 connections to neighboring neurons. Researchers are trying to figure out exactly how these cells influence neurons.

    • Glia communicate using chemical signals in the form of calcium waves, seen in the time lapse image. Calcium makes a fluorescent indicator glow, with brightness color-coded into warmer colors. The glia are responding to firing of action potentials in the long axons of neurons, seen as lightning bolts. Glia synchronize their signals by gap junctions or specialized channels between cells.
    _____________________________________________________________
    Google+ collaborations: ☆+Kevin Staff made this amazing animated gif from R. Douglas Field’s Movie: http://stke.sciencemag.org/cgi/content/short/3/147/tr5/DC1

    +Konstantin Makov picked out the music that evokes rapid fire connections flashing in our brains: Schnittke - Concerto Grosso No. 1 (Kremer)

    Dedicated to +Glia - The Social Glue founded by +Gregory Esau +Jeff Jockisch and others..check them out. For #ScienceSunday curated by +Allison Sekuler and +Robby Bowles .
  • 183 plusses - 32 comments - 174 shares | Read in G+
  • Rajini Rao2012-06-02 03:54:31
    I know that you believe you understand what you think I said, but I'm not sure you realize that what you heard is not what I meant.
    ― Robert McCloskey (1914-2003), Author of Make Way For Ducklings

    Image via http://imgur.com/gallery/4xPWp
  • 177 plusses - 138 comments - 127 shares | Read in G+
  • Rajini Rao2013-09-15 13:09:14
    Do You Like Green Eggs And Ham?

    Yes, I like them, Sam-I-Am
    White eggs, Brown eggs,  Pink ones too
    But Tell me, how Do they turn Blue?
    (With apologies to Dr. Seuss) 

    Egg color in birds evolved for obvious reasons of camouflage and recognition, and for less obvious reasons such as thermal regulation, protection against UV light, and even antimicrobial defense. Chicken eggs are commonly white (no pigment), or brown (protoporphyrin). Rare breeds from China and Chile lay blue eggs, colored by the bile pigment biliverdin, a breakdown product of the hemoglobin in red blood cells.  Biliverdin is normally excreted by liver cells into the bile. So how does it end up in the egg shell? 

    Organic anion transporters are proteins that move a large number of compounds- drugs, toxins, hormones and bile pigments, across cell membranes, as part of the liver's detoxifying day job. Genetic sleuthing mapped the blue color trait to a region of a chicken chromosome. Here was a gene for a transporter protein, SLCO1B3, that could provide blue-green biliverdin to color the shell. But why was the gene inexplicably turned on only in the shell gland of the blue egg laying chicken?

    Endogenous retroviruses (ERV) are ancient viruses that inserted randomly into the genomes of prehistoric birds. One such viral fragment inserted right next to the SLCO1B3 gene in blue egg laying chickens, where it behaved like an accidental transcription enhancer, or "on switch". Because of its sequence, scientists speculate that it mediates estrogen specific regulation, accounting for the high levels of the biliverdin transport protein in the shell gland. Although this story nicely explains our Seussian curiosity about green eggs and ham, it also shows how viruses shape diversity in the living world. For example, an insertion of the avian leukosis virus inside a gene for the enzyme tyrosinase results in white plumage in chickens. Viral insertions can also be incredibly harmful, triggering cancer when they accidentally turn on oncogenes.

    REFS (open access papers): http://goo.gl/3yJ1FS and http://goo.gl/ypZyCF

    Fun Fact: Green Eggs and Ham, published in 1960, is one of the best selling and most beloved children's books of all time. It has just 50 words, and was written by Dr. Seuss in response to a bet by his publisher. 

    Photo: Tammy Riojas, Elgin, TX;

    H/T to +Lorna Salgado for posting the news story that led to this   #ScienceSunday  post. 
  • 304 plusses - 96 comments - 61 shares | Read in G+
  • Rajini Rao2013-08-17 18:15:24
    Play of Color: Imagine a gem so iridescently beautiful that a phrase, play of color , is coined just to describe it. How does an ordinary sludge of sand and water, boringly described as hydrated silicon dioxide (SiO2. nH2O), express every color in the spectrum of light?

    Precious opal is formed when a solution of silica seeps through cracks in a rock very slowly : at a rate of one centimetre thickness every five million years. Under pressure, spheres of silica 150-300 nanometers wide, deposit in crystalline arrays. This regular packing, spaced close enough to the wavelength of light, has the effect of a diffraction grating, and the scattered light can be described by Bragg's Law. Nearly all the earth's supply of precious opal comes from Australia, formed in the Cretaceous period, more than a hundred million years ago. 

    Eric the Pliosaur: Now imagine a massive thick necked beast that once cruised through the Late Jurassic oceans, with a jaw four times stronger than T. rex and 10 times more powerful than any living creature. 150 million years later, our pliosaur has been "opalized" to an iridescent sheen, his fragments discovered by a lucky miner in Australia's Coober Pedy and sold for $250,000 USD to a wealthy businessman who subsequently lost his fortune.  Christened Eric the Pliosaur by a mischievous archaeologist who was asked to put the bones together, after Monty Python's Eric the Half a Bee, the fossil turned out to have a fish inside its belly, fittingly named Wanda. After a public campaign, Eric was eventually purchased for display by the Australian Museum.  What a thrilling journey for Eric. 

    ► Musical accompaniment: Monty Python - Eric the Half-a-Bee (1972)  

    Half a bee, philosophically, must ipso facto half not be .
    But half the bee has got to be, vis-à-vis its entity - d'you see?
    But can a bee be said to be or not to be an entire bee
    when half the bee is not a bee, due to some ancient injury?

    ► Pliosaurus: http://en.wikipedia.org/wiki/Pliosaurus
    ► Opalized Fossils: http://www.australianopalcentre.com/fossils.php

    #ScienceSunday   #fossilfriday  
  • 263 plusses - 65 comments - 100 shares | Read in G+
  • Rajini Rao2013-05-25 13:30:46
    Patterns in Nature

    Can you guess what this is? If you do, tell us one interesting fact about it or share your thoughts (try not to give the game away)!

    Here's one: This creature can detect infrared (thermal) radiation through heat sensitive ion channels that trigger firing of nerve fibers with accuracy >0.001 °C.

    Source: http://500px.com/photo/1539213
    #ScienceEveryday  
  • 234 plusses - 115 comments - 93 shares | Read in G+
  • Rajini Rao2013-07-14 12:48:27
    Artificial Chromosomes: Care for a Pair?

    ⌘ How about a new pair of chromosomes to add to the 23 pairs you already own? They make a great vehicle to insert new genes to reprogram cells, to replace defective or damaged genes. Current forms of gene therapy use modified viruses to deliver a stripped down version of a gene into cells. But these minigenes are hard to control. They may insert randomly into the chromosome and disrupt some essential function (“insertional mutagenesis”), trigger undesired immune response to the viral carrier, or rarely, activate a cancer-causing gene. Artificial chromosomes offer an alternative system of gene delivery. 

    Of YACs, BACs and Life HACs: Yeast artificial chromosomes (YACs) were first introduced 30 years ago, followed by bacterial versions (BACs) which are used in research as a convenient way to clone and sequence DNA from other genomes. More recently, human artificial chromosomes (HACs) have been successfully introduced into mice to cure Duchenne muscular dystrophy (http://goo.gl/xuvSS). 

    How to Build a HAC: You probably know that DNA combines with proteins (called histones), like pearls on a string, which are then packaged and condensed into a chromosome.  Chromosomes have short repeating fragments of DNA sequence, known as alpha satellites that can stretch for millions of base pairs, to form a centromere (the central knot of the X-shaped chromosome in the image below). The tips of the chromosome are capped with other protective repeating units called telomeres. Then there are the origins of replication, which are designated start sites for copying. An artificial chromosome has all these features too. It can be made by a top down approach: small fragments of telomere sequence (TTAGGG)n are introduced into a cell where they insert into chromosomes, triggering the loss of all sequences distal to the point of insertion. This eventually whittles down a chromosome until only a functional stump, about a tenth the size of a normal chromosome, remains. Alternatively, they can be assembled by a bottom up approach starting with de novo assembly of blocks of alpha satellite DNA. Entire genes, such as the large dystrophin gene defective in muscular dystrophy, can now be inserted, using special targeting sites (loxP). 

    Why are they better? Because the artificial chromosome has a centromere tethering it to the mitotic spindle during cell division, it can be partitioned into newly divided cells to survive stably in the long term. Second, there is no upper size limit to DNA cloned in a HAC: a gene with all its neighboring regulatory elements can be used so as to faithfully mimic the natural pattern of gene expression. In fact, groups of genes encoding complex pathways can be carried on a single HAC. Third, because of the lack of viral sequences, HAC vectors minimize harmful immune responses in the host and the risk of triggering cancers.

    ⌘ Scientist Gregory Stock thinks it may be another 20 years before we see artificial chromosomes put to use in humans. For now, artificial chromosomes are still difficult to introduce into cells, with efficiencies as low as 1 in 10,000.  “Bioengineers tend to underestimate the complexity of human biology,” he says. “These developments often come at a slower pace than we imagine. But they’re inexorable.”

    ▶ Image and Pop Sci story on the future of HACs: http://goo.gl/FfE5c
    ▶ Reference Paper on HAC (open access and easy to read introduction): http://goo.gl/cmkla

    #ScienceSunday  
  • 251 plusses - 63 comments - 96 shares | Read in G+
  • Rajini Rao2011-12-25 19:09:11
    Food Rules! While you are enjoying your holiday feast today, did you wonder why some flavors come together like a match made in heaven? Wine and cheese. Tomato and basil. Green eggs and ham. Okay, maybe not the last. A new study released in Nature investigates the science behind “The flavor network and principles of food pairing”. (Do you think field trips to restaurants were part of the study?).

    Hypothesis: Ingredients sharing flavor compounds taste better together than ingredients that do not. Currently held in vogue by many chefs and food scientists, this has led to new pairings of white chocolate and caviar, as they share trimethylamine and other flavor compounds, and of chocolate and blue cheese that share at least 73 flavor compounds (Chocolate, anyone?). Checkout http://www.foodpairing.com so you can experiment for yourself.

    Method and Analysis: Scientists used >56,000 recipes taken from three popular sites, epicurious.com, allrecipes.com (both American based) and menupan.com (Korean). Each ingredient had on average 51 flavor compounds (previously identified by food chemists). They then constructed a flavor network in which any two nodes (ingredients) were connected if they shared flavors. The more flavors shared, the thicker the connecting line. Only statistically significant links are shown (figure).

    Results: Network analysis showed that North American and Western European cuisines do indeed contain ingredients with many shared flavors. This was traced to abundant use of milk, butter, cocoa, vanilla,cream, and egg. Unexpectedly the opposite is true for East Asian cuisine! Asian food relies heavily on soy, ginger, scallions, pork and cayenne, ingredients that share very few flavor compounds. The study also identified “flavor principles”, or the most distinctive or authentic flavors of each culture: North American food relies heavily on dairy products, eggs and wheat; by contrast, East Asian cuisine is dominated by plant derivatives like soy sauce, sesame oil, and rice and ginger. (Okay, we knew this already ;) Also, South European cuisine is closer to Latin American in its flavor profiles whereas Western European food is similar to North American.

    Food for thought: As any good scientist knows, the discussion has to include evolution and fitness ;) The copy-mutate model : each ingredient is assigned a random fitness value, which represents the ingredient's nutritional value, availability, or flavor. For example, some ingredients are selected because of their antimicrobial properties. The mutation phase of the model replaces “less fit” ingredients with fitter ones. Meanwhile, the copy mechanism keeps copying the founder ingredients (ingredients in early recipes) and makes them abundant in the recipes regardless of their fitness value. What do you think?

    The paper is open access, do give it a read: http://www.nature.com/srep/2011/111215/srep00196/full/srep00196.html
    Higher Res Figure http://www.nature.com/srep/2011/111215/srep00196/fig_tab/srep00196_F2.html

    For #ScienceSunday curated by +Allison Sekuler and +Robby Bowles , who probably have better things to do today.
  • 149 plusses - 53 comments - 163 shares | Read in G+
  • Rajini Rao2013-03-07 13:09:22
    Eye See You

    • Fish eyes continue to grow larger throughout their lives because of stem cells that are concentrated at the ends of the red arcs (nerve tissue) seen in this zebrafish eye. This allows the visual cells of the retina to be repaired and regenerated continuously. The retina is seen wrapped around the lens (green circle with black center) in this cross-section.

    • The eye is really an outgrowth of the brain formed during embryo development. Take a look at the orange cells in the eyefield (inset A; ef) pushed to form two lateral bulges by the advancing midline (A-B; blue).

    • Humans (and other mammals) lack stem cells in the adult eye although research is focusing on Müller cells, a type of glial cell that may be able to regenerate neurons and photoreceptors lost to disease and injury.

    Image source: http://bpod.mrc.ac.uk/archive/2013/3/7
    Inset diagram: http://www.ucl.ac.uk/zebrafish-group/research/eye.php
    #ScienceEveryday  
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  • Rajini Rao2012-05-04 12:04:51
    FLOWER POWER: The insignificant little plant, Arabidopsis thaliana or thale cress, is a boon to biological research. And even the most ordinary flower looks beautiful through the eyes of a microscope, does it not?

    • Those of us focused on understanding human disease don't pay much attention to research in plants. But plant biologists have taught us about micro RNAs, transposons, active demethylation, 'decoy' RNAs, and more. The wonderful world of genetics was first revealed through the patterns of inheritance of sweet peas, by one Austrian friar named Gregor Mendel.

    • That's why I go to a plant conference once every few years. I never know what I may pick up and plant biologists are gracious enough to listen to our animal work.

    #floralfriday +FloralFriday

    Image: Mendel's Dream Arabidopsis flower captured with confocal microscopy by Heiti Paves, Centre of Excellence ENVIRON, Estonia.
  • 243 plusses - 83 comments - 84 shares | Read in G+
  • Rajini Rao2012-04-29 14:35:14
    THE VISIBLE HUMAN: a complete, anatomically detailed, three-dimensional scan of the male and female human body.

    How was this done? The male cadaver was frozen in gelatin and cut horizontally at 1 mm intervals into 1,871 slices and photographed to give 65 GB of high resolution images. The female was cut at 0.3 mm intervals resulting in ~40 GB of data. In addition, the bodies were scanned by CT (computer assisted tomography) and MRI (magnetic resonance imaging).

    If that wasn’t macabre enough: Both bodies were donated to science but because the donors did not know their specific use and the male died by lethal injection, ethical issues have been raised. Also, these are not perfect bodies. The male lacks one testicle. The female shows signs of cardiovascular disease.

    Art and Anatomy: Artist Lisa Nilsson was inspired by the images to create painstakingly realistic replicas with rolled up paper, an art form known as quilling. Her artwork takes weeks to create and sells for up to $7,000.
    See the slide show here: http://www.huffingtonpost.com/2012/04/26/lisa-nilsson-art-paper_n_1456502.html

    Watch complete scan (1:15 min) in HD: it is stunning The visible human project - Male (HD)

    Sponsored by the US National Library of Science (NLM), the goal of this ambitious project was to facilitate scientific discovery and teaching of anatomy. http://www.nlm.nih.gov/research/visible/visible_human.html

    H/T to +Daniel Mariani who found the animated gif from Reddit (original creator unknown). +Chad Haney knows way more about imaging than I do.

    +ScienceSunday
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  • Rajini Rao2013-07-28 17:03:14
    What do you see? An alien sun rising over some distant desert landscape? Arid rivers marking the surface of Mars? Leave your guesses in the comments! #ISeeTheWorldWithScience  

    Forests in Flames: Actually, this photo was commissioned by the United Nations to bring attention to deforestation from coca cultivation. Three countries account for the global cocaine production: Peru, Columbia and Bolivia. A study led by SUNY professor Liliana Dávalos showed that in a 5 year period, coca cultivation led to the destruction of 890 square kilometers of rainforest. That accounts for ~6 percent of rainforest loss, totaling 14,000 square kilometers, or an area slightly larger than Jamaica. Spraying with herbicide proved to be an ineffective deterrent: for every 30 hectares sprayed, only one was eradicated. In contrast, government protection of land seemed to prevent illegal growth of coca plants. 

    Sunburned Eyes: Dilated pupils and red eyes are a visible sign of cocaine use. Curiously, cocaine was used to treat snow blindness, an extremely painful form of sunburn of the eye caused by UV radiation bouncing off snow cover. Did you know that British explorer Ernest Shackleton packed medicinal cocaine for his expedition to the South Pole in 1907 (see here for a fascinating pix http://goo.gl/W8Jo5). [Note: Shackleton came close, but did not make it to the South Pole. Later, his wife recounted : "The only comment he made to me about not reaching the Pole was "a live donkey is better than a dead lion, isn't it?"] 

    Snow Blind Friend:The Urban Dictionary defines Snow Blindness as Cocaine addiction, as heard in this poignant song by Steppenwolf: SNOWBLIND FRIEND live John Kay & Steppenwolf 1989

    He said he wanted Heaven but prayin' was too slow
    So he bought a one way ticket on an airline made of snow

    John Kay, the charismatic frontsman of Steppenwolf, was legally blind with a congenital disorder of cone cells leaving him with complete color blindness and only black and white vision.  

    Ref: Forests and Drugs: Coca-Driven Deforestation in Tropical Biodiversity Hotspots. Dávaloset al.,  http://goo.gl/B1NVbs
    Photographer: Javier Crespo, Leo Burnett Colombia advertising agency.

    #ScienceSunday 
  • 243 plusses - 117 comments - 57 shares | Read in G+
  • Rajini Rao2013-12-24 14:43:26
    Science Santa and a Cellular Christmas

    Twas the night before Christmas, when all through the lab
    Not a creature was stirring, not even a postgrad.
    The pipetmen and tip boxes were arranged with care,
    In hopes that science elves soon would be there.

    The postdocs were nestled all snug in their beds,
    While visions of job offers danced in their heads.
    And the PI, at home, took off her many caps
    And rested her brains for a well-deserved nap. 

    When from the cell culture room there arose such a clatter
    The grad student rushed to see what was the matter? 
    Away to the culture hood he flew in a flash
    Turned off the UV light and raised up the sash.

    The neurospheres bobbed merrily in their own private party
    Transiently transfected, they proliferated smartly.
    The epithelial cells broke free from their tight junctions 
    Downregulating e-cadherin and migrating to the function.

    The mycoplasma were raising microscopic mayhem
    And the opportunistic fungus could barely be stemmed.
    But hush! There came silence and the ruckus stalled
    For here is Science Santa with presents for all!

    Data for the PhD candidate in her fifth year
    The replicates have p values <0.005, never fear!
    Acceptance without revision from the journal Nature?
    The young post-baccalaureate just advanced in stature.  

    A tenure-track position, which was his sole goal
    Now the senior postdoc won’t be on the dole.
    For the PI, her broken budget can finally be mended 
    That R01 in the 5th percentile will surely be funded?!

    With a wink of an eye and a twitch of his nose
    His bounty unloaded, up and away he rose.
    Then Science Santa called, as he flew into the New Year
    Happy Experimenting to all, and to all Good Cheer!

    CELLULAR CHRISTMAS
    Donna Stolz (Univ. Pittsburgh) created this festive wreath by assembling images of mammalian cells from more than 25 experiments. 

    Apologies to Clement Clarke Moore who wrote the original (and better) poem in 1822: http://www.carols.org.uk/twas_the_night_before_christmas.htm

    Suggestions, additions or edits to the bad rhyme? :)
    #MerryChristmas   #ScienceEveryday  
  • 254 plusses - 72 comments - 69 shares | Read in G+
  • Rajini Rao2014-03-06 19:02:22
    SOFTWARE UPDATE: Gene Editing Could Rescue AIDS Patients

    HIV Gains Foothold: The human immunodeficiency virus, HIV, gains entry into immune T cells by initially binding to the cell surface receptor protein CD4 and then recruiting a co-receptor, usually CCR5. Infected T cells eventually die and the patient becomes susceptible to other infections, described as acquired immunodeficiency syndrome or AIDS. 

    As Luck Would Have It: About ~700 years ago, a chance mutation in the CCR5 gene appeared that inactivated the receptor. This mutation, CCR5-Δ32, has a slight negative fitness effect because CCR5 is one of many chemokine receptors important in the inflammatory immune response. The mutation should have dwindled or disappeared. Instead, the mutation underwent intense positive selection, now prevalent in ~10% of the European population. Modeling studies suggest that the mutation helped fight off small pox virus, conferring an unexpected survival benefit. Today, it provides resistance to HIV: one copy of the mutation delays AIDS onset ~ 2 years, while 2 copies confers resistance to the common HIV-1 R5 strain. 

    The Berlin Patient: A famous case of "natural gene therapy" involved Timothy Ray Brown who was being treated for HIV infection in the mid-nineties. Brown then developed leukemia in 2006 and his condition deteriorated. He received a stem cell transplant from a German donor whose CCR5 genes carried the resistant mutation. Not only did the treatment cure Brown's leukemia, it also eliminated the HIV infection (http://en.wikipedia.org/wiki/The_Berlin_Patient).  

    Gene Editing: Recent efforts are designed to be more accessible for AIDS patients. The idea is to remove T cells from the patient, manipulate the CCR5 gene to insert mutation, then re-introduce the modified T cells back into the patient. A small-size feasibility and safety study was reported this week (http://goo.gl/TlRBrG) involving 12 patients: 6 received modified T cells and were taken off anti-retroviral therapy for 4 weeks. The results were promising! T cell counts increased in the treatment group, and the modified cells outlasted the unmodified cells by 7-fold. The paper is behind a paywall, so please ask if you have questions!  The news story is here: http://goo.gl/j5jkws

    Image shows an immune T cell (yellow) in the lower right, budding off particles of HIV (green) seen in a colored transmission electron micrograph from  http://www.sciencephoto.com/media/549097/. To the upper left, is a molecule of CCR5 (yellow) embedded in the cell membrane (grey lipid) from Wikimedia (http://goo.gl/svUNsE).

    #ScienceEveryday   #ScienceSunday  
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  • Rajini Rao2013-01-31 13:34:22
    Soldier Gets a Rare Double Arm Transplant

    Brendan Marrocco was on patrol in Iraq 3 years ago when an explosion claimed all four of his limbs. He was the first Army soldier to survive a quadruple amputation. Now, he is the first soldier to receive a very rare double arm transplant at the Johns Hopkins Hospital. He is 26 years old.

    Logistics: The surgeons practiced four times on cadavers before the real thing. There were 4 teams of 3 surgeons each: one for each arm from donor and recipient. The deceased donor and living recipient do not need to match in gender, but in size, skin color, tissue and blood type.

    How They Did it: First, the skin is peeled back and bones are sawed at an angle to dovetail into each other when attached  by metal plates- good carpentry, in essence. Next, the muscles and tendons are tagged with pieces of light blue sterile bandage that are sewn in place and labeled in permanent black marker, before being connected. The arteries and veins are painstakingly attached under a microscope, and finally the skin is sewn together.

    What was New: Brendan was given an infusion of bone marrow from vertebrae in the donor’s lower spine. This lowered the chance of rejection and cut back on the use of potentially dangerous drugs.

    Two Thumbs Up: Brendan's nerves will grow into his new arms at a rate of an inch a month. In the one month since his landmark surgery, he can already move one arm around. Eventually, patients are expected to be able to "tie shoes, use chopsticks and put their hair in ponytails". Brendan might consider growing his hair longer for that :)

    Video and Story ▶ http://goo.gl/XFPse

    #ScienceEveryday  
  • 207 plusses - 127 comments - 66 shares | Read in G+
  • Rajini Rao2012-12-23 17:15:18
    Flowers that Fly: Science of the Butterfly Wing

    Butterflies are beautiful: Their eggs rival Faberge’s for sheer art. The migration of the Monarch butterfly holds navigational secrets still beyond our ken. But the wings are truly remarkable for their mimicry, polymorphism (variation) and aposematism (warning coloration). Like tiny shingles on a roof, microscopic overlapping scales cover the wings with brilliant, iridescent colors.

    Structural Coloration: Black and brown colors are from melanin, but the blues, greens and reds are created by the microstructure of the scales and not by pigments. Originally observed by Robert Hooke and Isaac Newton, the principle of wave interference was described by Thomas Young a century later. Surfaces scored with fine parallel lines or thin layers on the same scale as the wavelength of light reflect multiple sets of waves. These can interfere with one another by adding or subtracting, to give rise to iridescence.
    For more, see: http://en.wikipedia.org/wiki/Structural_coloration

    A Quick Getaway: The scales of a butterfly wing readily detach, allowing for quick escape from a spider’s web or predator’s grasp. Thomas Eisner experimented by dropping various insects on a spider web. Of the butterflies and moths, he noted, “They all left impact marks on the webs where scales became detached to the viscid strands. Moth scars we came to call such telltale sites, and soon learned that they were common." Most birds largely ignore butterflies. It turns out they are rather difficult to catch, without a large net, due to their erratic flying trajectories. Read Thomas Eisner’s essay on Butterfly Wings: http://goo.gl/5Sfon

    • Beauty of the Butterfly Egg: http://goo.gl/0cnas

    • Migration of the Monarch Butterfly: http://goo.gl/WuT6z

    • If you like Opera: Maria Callas (Μαρία Κάλλας): Madama Butterfly - Puccini

    Blue-Butterfly Day by Robert Frost:

    It is blue-butterfly day here in spring,
    And with these sky-flakes down in flurry on flurry
    There is more unmixed color on the wing
    Than flowers will show for days unless they hurry.

    But these are flowers that fly and all but sing:
    And now from having ridden out desire
    They lie closed over in the wind and cling
    Where wheels have freshly sliced the April mire.

    #ScienceSunday  
  • 235 plusses - 86 comments - 65 shares | Read in G+
  • Rajini Rao2012-10-16 11:53:03
    Today is Ada Lovelace Day

    Who? Augusta Ada King (nee Byron), Countess of Lovelace (1815-1852), was an English mathematician and the brains behind Charles Babbage's analytical engine. This Enchantress of Numbers is considered (by some) as the first computer programmer.

    Why? The goal is to raise the profile of women in science, technology, engineering and maths by encouraging people around the world to talk about the women whose work they admire. Psychologist Penelope Lockwood says, “Outstanding women can function as inspirational examples of success. They demonstrate that it is possible to overcome traditional gender barriers, indicating to other women that high levels of success are indeed attainable.”

    How? Just follow these simple steps to become a part of the worldwide celebration of women in STEM: Write about a woman in science, technology, engineering or maths whose achievements you admire. Publish your story online at findingada.com and here on G+, tagged #adalovelaceday .

    #stemwomen #scienceeveryday #adalovelaceday  
  • 140 plusses - 51 comments - 135 shares | Read in G+
  • Rajini Rao2012-03-21 10:40:10
    Jane Goodall: Chimpanzees still need our help desperately. There are less than 300,000 chimps left, spread thinly over 21 African nations. Their numbers have been plummeting now that hunters can gain ready access into the bush using logging roads. We lose 10 hectares of forest per minute on this planet. Goodall says that the most effective way to save the chimps is to save the forests.

    http://www.janegoodall.org/
    Source: http://tinyurl.com/7e26ccl
    #threatenedthursday in support of conservation and the new themed page curated by +Sumit Sen et al.
  • 129 plusses - 46 comments - 143 shares | Read in G+
  • Rajini Rao2012-07-16 22:45:53
    ANAMORPHOSIS: An art form where the image is greatly distorted, appearing only from a specific vantage point or upon reflection in a cylindrical mirror (or reflecting cones and pyramids). The painting (by Julian Beever) on the pavement is fragmented and meaningless to most viewers. But find the sweet spot, and Whoa! A giant snail appears to crawl on the city bench. (www.julianbeever.net)

    • Leonardo da Vinci is thought to have made the first anamorphic drawing in 1485, at a time when Renaissance artists were experimenting with perspective (Leonardo's Eye -Illusion).  Hidden images conveyed dangerous political statements, heretical ideas, and even erotic images.

    The Ambassadors: A famous example is the 1533 painting by Hans Holbein called "The Ambassadors". When viewed from an extreme angle, a smudge at the bottom in an otherwise conventional painting reveals itself to be a grinning skull. Hans_Holbein the younger_The Ambassadors (amazing skull )
    What does it mean? Holbein's skull - Part one | Paintings | The National Gallery, London

    Medusa's Head pays homage to the legend of Perseus, who could only look upon the snake headed monster in the reflection of his shield: http://www.moillusions.com/2011/12/an-anamorphic-medusa-painting.html

    What are your favorites in illusory art?
  • 111 plusses - 35 comments - 158 shares | Read in G+
  • Rajini Rao2013-12-20 13:27:02
    The Science of Snow!

    Stellar dendrites are falling. Rimed crystals are piling on so heavily, they you may see graupel. If you're lucky you may spot a split star or a rare capped column. No, I'm not talking gibberish! You can check the “Meteorological Classification of Natural Snow Crystals,” (1966) by Magano and Lee.  Did you know that there are 80 official patterns of snowflakes? Their characteristic 6-sided shape comes from the hexagonal lattice of water molecules: each vertex has an oxygen atom with the edges formed by hydrogen bonds on either side (see http://goo.gl/8ZUI0G). 

    Is it true that no two snowflakes are alike? The short answer is yes! At the atomic level, suppose one snow crystal has 10^18 water molecules, of which 10^15 will contain deuterium isotope (hydrogen with mass of 2 instead of 1) or an isotope of oxygen (mass of 18 instead of the more common 16). Imagine the different ways these could be arrange in the crystal. Then consider the hundreds of different morphological features of snowflakes and the ways they may be arranged. If 100 books could be arranged on a shelf in 10^158 ways (1 followed by 158 zeroes, which is more than all the estimated atoms in the universe), the probability that two identical snowflakes exist is infinitesimally small.  

    How to view a snowflake at >1,000 times magnification? What you see will surprise you. They don't look quite that regular or perfect. Their art form is more steam punk than a Hallmark holiday card. You may even see the face of Optimus Prime or an alien starship.  

    1) Capture freshly fallen snow from around the country. It's more naturally diverse than the man-made stuff that is smooth and gob-like.

    2) Brush the flakes on to a pre-chilled copper plate coated with a gel of methyl cellulose.

    3) Chill right away in liquid nitrogen, down to -196 C.

    4) Mount on a scanning electron microscope with a viewing stage chilled to -176 C.

    5) Justify your work: "'Information gained from studying the structure of snow is vital to several areas of science as well as to activities that affect our daily lives..."  from USDA.gov :)

    Happy Holidays! 

    REF: For all you wanted to know about snow and more http://goo.gl/nDnTM

    Cover Photograph by Ph.D. candidate Si Chen. Dartmouth Engineer Magazine http://goo.gl/FsqqR1
    Others: The Electron Microscopy Unit of the Beltsville Agricultural Research Center in Beltsville http://goo.gl/xteHY

    #ScienceEveryday   #HolidayScience  
  • 219 plusses - 60 comments - 80 shares | Read in G+
  • Rajini Rao2012-02-18 21:23:58
    If at first you don't succeed.....

    • ... try, try, try again. ~William Hickson
    • ....do it like your mother told you. ~Author Unknown
    • ....destroy all evidence that you tried. ~ Steven Wright
    • ....then skydiving definitely isn't for you. ~Steven Wright
    • ... find out if the loser gets anything. ~Bill Lyon
    • ....before you try again, stop to figure out what you did wrong. ~Leo Rosten
    • ....redefine success. ~Author unknown.
    • ....failure may be your style.~Author unknown.
    • ....try, try again. Then quit. There's no point in being a damn fool about it. ~W. C. Fields

    Source: Photographer Christopher Tomas captured this shot of a Qantas Dash 8 plane flying across the surface of the moon after many, many tries. No tricks, no Photoshop.
  • 187 plusses - 62 comments - 97 shares | Read in G+
  • Rajini Rao2012-12-31 18:32:01
    The Physics of Champagne

    Champagne is a multicomponent hydroalcoholic system supersaturated with dissolved CO2 gas molecules formed together with ethanol during the second fermentation process. 

    Better Bubbles: Did you know that a bottle of champagne (0.75 L) holds about 10 g/L of dissolved CO2. When uncorked, this equals 9 L of gas (6 times the volume of the bottle!) which quickly escapes the supersaturated liquid to form a new thermodynamic equilibrium with air. The quality of champagne is determined by the fineness and abundance of effervescence: the bubbles tickle mechanoreceptors and taste buds in our mouth and carry volatile aromatics to our nose. 

    Tradition vs. Science: In bars and restaurants, champagne is poured vertically to hit the bottom of the glass, providing a thick head of foam, which quickly extends up and then progressively collapses during serving. But if champagne is poured like beer, it flows along the inclined edge and progressively fills the flute. Infrared thermography (left image) and measurement of dissolved CO2 (right image), showed that the beer-like method is best, but this scientifically validated method has not been adopted because of prejudice associated with the more plebian beer.  

    Chill It: The colder the champagne, the more dissolved CO2 is retained during the pouring step, as seen in the graph. 

    Flute or Coupe?: Measurements of CO2 fluxes outgassing from glasses showed significantly higher losses in the coupe than in the flute, providing analytical proof that the flute prolongs the drink’s chill and helps it to retain its effervescence, in contrast with the wide, broad brimmed coupe.

    The Glug-Glug Effect: The first few glasses of champagne have less dissolved CO2, so be gracious and wait your turn! This turns out to be due to the onomatopoeic “glug–glug” effect caused by the liquid first flowing rather chaotically out of the bottle, through a succession of jets of liquid and admissions of air bubble, inexorably accelerating the loss of dissolved CO2 concentration through turbulences and bubble entrapment. Later, as the bottle fills with air, the champagne flows out more smoothly retaining more CO2. 

    References: On the losses of dissolved CO(2) during champagne serving.
    Liger-Belair et al., 2010 J Agric Food Chem. 58:8768-75. 

    Monitoring gaseous CO2 and ethanol above champagne glasses: flute versus coupe, and the role of temperature. Liger-Belair et al.,2012 PLoS One. 7:e30628. 

    NPR listen/readhttp://goo.gl/O68Qe

    #HappyNewYear   #ScienceEveryday  
  • 184 plusses - 122 comments - 71 shares | Read in G+
  • Rajini Rao2012-12-15 19:41:25
    From Protein Folding to Punjabi Pea Paneer

    ✿ Making fresh Indian cheese, or paneer, used to be a bit of a production in my home. My mother would start with not-so-fresh milk (why “waste” good milk, was her reasoning), bring it to a boil and then add lemon juice. In fascination, I watched the rapid separation of flocculant white curd from transparently greenish whey. That was my first encounter with the biochemistry of protein denaturation, although I would go on to ruin perfectly good batches of enzymes during my graduate career.

    Proteins must be folded properly – into elegant ribbons, twisted helices, graceful loops and tight turns – not only to function properly but also to stay in solution (image 2). Too much heat, salt, acid or any number of adverse conditions cause proteins to unfold just enough to get their sticky inside parts to glom together. In a concerted show of protest, they leave the solution as a precipitate. Which brings us back to cheese. The curd is gathered into cheesecloth and suspended over a bowl to drain, before being packed into a brick under some heavy pots and pans. These days, one just reaches into the freezer of the local Patel Brothers for a perfectly rectangular brick of paneer.

    ✿ This quintessential Punjabi dish of peas and paneer is called Mattar Paneer. The gravy is vegan, with richness of cashew nuts in place of dairy cream. You can make this dish entirely vegan by replacing the paneer with baby potatoes boiled in their jackets (Alu Mattar..mmm!) or a cheese substitute of your choice.

    ✿ Recipe, a memorium to a lost G+ friend, and a harrowing tale of protein denaturation from my graduate student days at: http://madamescientist.wordpress.com/2012/12/10/from-protein-folding-to-punjabi-pea-paneer/

    #ScienceEveryday  
  • 228 plusses - 158 comments - 27 shares | Read in G+
  • Rajini Rao2013-03-15 23:06:39
    My Day on the Hill

    This week, several hundred scientists - astronomers, chemists, biologists and engineers from across the nation, descended on Capitol Hill to lobby for science. We asked for sustained and predictable federal funds for scientific research. We voiced our worry that deep cuts in grants would destroy a generation of scientists: that research is not a faucet that can be turned on and off, because the well at the source dries up. We brought a personal face to the projects we were working on.

    What did I learn? Our visit began with a briefing at the AAAS auditorium in Washington, DC. The Office of Science and Technology from the White House gave us the executive branch perspective by breaking down the budget into entitlements and discretionary spending, and showing us the thin slice of pie that went to Federal R&D. Then we got a Congressional perspective from both the House and Senate committees on Science, Space and Technology. These career administrators were scientists themselves, very much "on our side". The next day was a blur of individual visits to offices of senators and congressmen from our states, efficiently organized by the +Biophysical Society whom I was representing. The deal was that we spoke to staffers, and the staffers spoke to the elected members of Congress. We handed out folders full of statistics, talking points and projections. We shook hands, took pictures and exchanged cards.

    Was it worth it? In the long run, yes. Maybe. Like the democratic process, visiting Congress is both our right and responsibility. I left with a better understanding of how Congress runs, and hopefully, made some contacts. It's going to be easier to write to my elected representative the next time I'm called upon to lobby for science.

    Was it fun? Definitely, this was an unforgettable experience. Senate offices are posh! Marbled halls, deep carpeting, brass-studded heavy doors. The House? Not so much. Congress is run by 20-30 somethings: smart but poorly paid, staffers put in long hours and typically don't last more than a year. It was fun to spot faces: there was Sen. Barbara Boxer rushing past us, Rep. John Dingell leaning heavily on his cane, while another senator saw off some fund raisers at his door. 

    #ScienceEveryday  
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  • Rajini Rao2013-01-25 22:43:08
    Scarecrows and Wreaths: Genetic Secrets of Efficient Food Crops
     
    • Ancient plants, like rice, wheat and barley, originating in the Mesozoic and Paleozoic eras, still form 95% of the Earth’s plant biomass. They use an enzyme known as RuBisCo (the most abundant protein on the planet!) to fix atmospheric carbon dioxide on to a 5-carbon sugar (ribulose bis-phosphate) to make 2 molecules of a 3-carbon sugar that eventually becomes sucrose. This is the C3 pathway, but it's not too efficient: the enzyme RuBisCo also catalyzes a competing reaction called "photorespiration" that adds oxygen to the 5-carbon sugar making a byproduct that takes many tedious and expensive steps to convert back to the useful sugar. These plants can also lose 97% of the water absorbed by the roots through stomata or pores on the underside of the leaves. If they close their stomata, they limit the diffusion of CO2 into leaves, so they have limited growth in hot, dry areas.

    • Fortunately, in the last 6-7 million years, another group of plants (sugarcane, maize, grasses) began to flourish that bypassed this problem. They evolved from the C3 plants independently, more than 60 times- a spectacular example of convergent evolution.  In these plants, a different enzyme is used to fix CO2 to make a 4-carbon sugar in the leaf cells, that is then shuttled into special wreath-like layer around the veins, known as Kranz sheath (German for wreath).  Kranz cells release CO2 from this intermediate, insulating and concentrating it around the Rubisco enzyme so that the wasteful side reaction does not occur. This highly effective C4 pathway boosts productivity by 50%. Even though C4 plants make up only 3% of plant species, they account for 30% of all carbon fixation on land.

    • How does one coax C3 plants to follow C4 pathways and boost food production in hot, dry areas, while removing more CO2 from the atmosphere? C3 plants have all the enzymes needed, but lack the specialized anatomy of the wreaths and the tight spacing between veins. It was assumed that engineering Kranz anatomy would be exceptionally difficult. In a breakthrough study, scientists noted common features of the Kranz sheath with root and stem bundles, suggesting a common developmental pathway. Working on a hunch, they showed that a gene called Scarecrow, regulates the special anatomy in both roots and leaves.  “Recapitulating the evolution of C4 structure in C3 plants is likely to be a much more manageable goal if the underlying regulatory components are already in place in roots and stems”.

    Image: Kranz anatomy in French Millet, a C4 plant. Note the bundle sheath, packed with green chloroplasts, around the central vein, and the tight spacing of less than 4 cells between the bundles. http://goo.gl/J004P  
    Read More: http://www.news.cornell.edu/stories/Jan13/Scarecrow.html
    http://en.wikipedia.org/wiki/C4_carbon_fixation

    Paper: Scarecrow plays a role in establishing Kranz anatomy in maize leaves. Slewinsky, T.L., et al. Plant Cell Physiol. 2012 Dec;53:2030-7. doi: 10.1093/pcp/pcs147.

    #ScienceEveryday when it's not #ScienceSunday .
  • 165 plusses - 118 comments - 81 shares | Read in G+
  • Rajini Rao2012-07-25 00:41:28
    Would you give up sex for eternal life? This little invertebrate, a bdelloid rotifer, has lived a celibate life for ~80 million years. The males have disappeared and the females reproduce by parthenogenesis. A drawback to this convenient scheme is that our DNA is usually repaired during meiosis, when we form gametes or germ cells.

    • Scientists bombarded these little creatures with gamma rays that would typically shatter DNA into little bits. To their astonishment, the rotifers kept reproducing even at levels of radiation five times more than other animals can endure. Their secret lies in genetic redundancy: their genomes have duplicated, so that each gene is in 4 copies. When one is damaged, the others serve as template to copy off a new version (gene conversion).

    • How did this resistance to radiation damage evolve? These animals live in fresh water pools that can dry up at any time. The rotifers can go dormant for weeks to years, springing back to life with water. Dessication has the same effect on DNA as radiation so the rotifers must have evolved to survive in their ephemeral habitats. "There could be some benefit to millions of years without sex after all", says Dr. Alan Tunnacliffe, University of Cambridge :)

    Live image of Philodina roseola , details at http://www.cellimagelibrary.org/images/41670

    Refs: (1) Gladyshev, E., and M. Meselson. 2008. Extreme Resistance of Bdelloid Rotifers to Ionizing Radiation. Proc. Natl. Acad. Sci. 105 (13): 5139-5144.

    (2) Mark Welch, D.B., J.L. Mark Welch and M. Meselson. 2008. Evidence for degenerate tetraploidy in bdelloid rotifers. Proc. Natl. Acad. Sci. 105 (13): 5145-5149.
  • 162 plusses - 150 comments - 68 shares | Read in G+
  • Rajini Rao2012-01-02 21:12:52
    Connection-Junction: The Synapse. It’s all about networking. Synapses connect nerve cells to each other, or to muscles and glands.

    • The word synapse is derived from the Greek syn (together) and haptein (to clasp).

    • There are an estimated 100-500 trillion (that’s 10^14) synapses in the human brain.

    • The space (synaptic cleft) at the junction is narrow, only 20 nanometers wide.

    • Messages travel down the nerve fiber in the form of an electric pulse known as the action potential. When they get to the synaptic terminal, these messages must be converted to a chemical signal that crosses the narrow cleft (within microseconds) to trigger a new electrical signal at the connecting nerve or muscle cell. The chemical signal is the neurotransmitter (glycine, acetylcholine, etc.).

    • These chemicals are packaged into small vesicles that lie just under the nerve membrane, docked and ready to fuse. When the action potential arrives, the vesicles execute a quick “kiss and run” to release the neurotransmitter into the cleft.

    • Here is a beautiful scanning electron microscope image of a nerve ending in which the membrane has been sheared away, revealing hundreds of spherical vesicles ready to release their neurotransmitter cargo into the synaptic cleft.

    • Synapses are targets for hundreds of toxins, psychoactive drugs and poisons including curare, cocaine, LSD and morphine. Botox is a formulation of botulinus toxin, and works by cleaving the proteins that allow the vesicles to fuse. By blocking neurotransmitter release, the nerve cannot signal the muscle to contract. Voila, no wrinkles!

    Image from: http://www.cellimagelibrary.org/images/214
  • 160 plusses - 66 comments - 104 shares | Read in G+
  • Rajini Rao2012-03-17 19:28:30
    The Art of Science: "Science is an inherent contradiction — systematic wonder — applied to the natural world. In its mundane form, the methodical instinct prevails and the result, an orderly procession of papers, advances the perimeter of knowledge, step by laborious step. Great scientific minds partake of that daily discipline and can also suspend it, yielding to the sheer love of allowing the mental engine to spin free. And then Einstein imagines himself riding a light beam, Kekule formulates the structure of benzene in a dream, and Fleming’s eye travels past the annoying mold on his glassware to the clear ring surrounding it — a lucid halo in a dish otherwise opaque with bacteria — and penicillin is born . Who knows how many scientific revolutions have been missed because their potential inaugurators disregarded the whimsical, the incidental, the inconvenient inside the laboratory?”

    Excerpt: A General Theory of Love by Thomas Lewis, Fari Amini, and Richard Lannon.
    Source: http://www.brainpickings.org/index.php/2012/02/23/systematic-wonder/

    Do You want to Live in the Overlap? ☼
  • 108 plusses - 61 comments - 133 shares | Read in G+
  • Rajini Rao2013-05-01 10:41:34
    A Boy and His Atom

    How do you make the world's smallest movie? By moving atoms, one at a time. Certified by the Guinness Book of World Records, this stop motion animation made by IBM nanophysicists only lasts 60 seconds and shows a tiny atomic "boy" jumping on an atomic trampoline and playing with his ball atom, magnified 100 million times. It took 242 frames, each made by a scanning tunneling microscope that weighs 2 tons and operates at -268 degrees Celsius (or 450.5 degrees below zero on the Fahrenheit scale). A needle comes within 1 nanometer of each atom (actually diatomic carbon monoxide), grabs and drags it across the surface of a tiny chip to a new location..you can hear the dragging sound in the "behind the scenes" movie.

    Why was this movie made? According to Moore's Law, chip performance doubles every 18 months, as the individual transistors become smaller. Currently, it takes about a million atoms to store individual bits of data, but IBM scientists see that number shrinking to 12. At this size, you could fit every movie made on your iPhone. Moving individual atoms precisely becomes important at these tiny dimensions. Hey, scientists like to have fun too! And, as Andreas Heinrich says, if a thousand kids watching A Boy and His Atom decide to go into science instead of law, that's a win for #STEM . Sorry, lawyers, you had Law and Order :)
     
    ⚛ Watch: Moving Atoms: Making The World's Smallest Movie

    #ScienceEveryday  
  • 164 plusses - 42 comments - 106 shares | Read in G+
  • Rajini Rao2012-09-02 12:30:47
    3D Indy: Nano Racecar

    • This model of an Indy Car, about the width of a human hair, was made in 4 minutes using a 3D printer.  Printing three dimensional objects at a nanoscale with incredibly fine details is now possible using two-photon lithography.  Scientists at Vienna University of Technology have broken the record for speed printing, going from a few mm/sec to 5 m/sec! This is done using precisely controlled mirrors to focus a laser beam on printed resin. Because the resin hardens only when activated by 2 photons of light, at the very center of the laser beam, solid material can be created anywhere in the liquid resin instead of only at the surface.  Potential applications include making scaffolds to build human tissue or body parts.

    • Meanwhile, at this weekend’s  Grand Prix races, real life Indy Cars will roar through downtown Baltimore, looping through 2 miles of familiar city streets at speeds >175  miles per hour.   (I drive the same streets at a slightly more sedate pace on my way to work every day.) This uniquely urban track includes 12 turns over 200 bolted-down manhole covers in the heart of a 300 year old city, past the picturesque Inner Harbor along the Chesapeake Bay. Watch what happens when Tony Kanann’s breaks fail  at 180 mph during last year’s Grand Prix in Baltimore. Amazingly, the drivers walk away unscathed. Tony Kanaan and Helio Crash at Baltimore
    Also: IndyCar Highlights from Baltimore

    • Watch the high speed printing of a nanorace car by a 3D printer: High speed fabrication of race car
    • More Info: http://www.tuwien.ac.at/en/news/news_detail/article/7444/

    #sciencesunday for +ScienceSunday curated this week by +Allison Sekuler and three guest curators: +Buddhini Samarasinghe , +Rich Pollett and +Gail Barnes .
  • 169 plusses - 37 comments - 105 shares | Read in G+
  • Rajini Rao2012-03-12 14:48:18
    True or False? You only use 10% of your brain. This is a popular myth that has been proven false by brain imaging. While not all of the brain is active at the same time, fMRI (functional magnetic resonance imaging) shows widespread activation of the brain for even simple tasks. Take a moment to admire the connectivity of our brain in the image, made by a type of MRI called diffusion spectrum imaging.

    Brain Awareness Week: Today kicks off a global campaign to focus attention on the field of neuroscience, improve public health and outreach by informing on brain research and brain disorders, and to inspire the next generation of scientists. Look for more brain posts and cool neuroscience research all this week!

    Sponsored by The Dana Foundation (http://www.dana.org/brainweek/) and partnered with the Society for Neuroscience (http://www.sfn.org/index.aspx?pagename=baw_home).
  • 151 plusses - 90 comments - 88 shares | Read in G+
  • Rajini Rao2013-02-10 15:23:18
    The Science of Sound
     
    Sounds of Laughter, Shades of Life The birds do it. The bees do it too and so do you. An amazing range of animals generate sound: pressure waves caused by displacing the medium in which they travel.
     
    Tiny Noisemaker You may think that's the screaming baby across the airplane aisle, but human speech is at a comfortable 60 dB. The decibel, named after Alexander Graham Bell, is logarithmic in scale: an increase of 10 dB is actually ten times as loud. Anything above 85 dB is dangerously painful and the loudest sound tolerated by the human ear is 120 dB.  The loudest animal is the sperm whale at an ear-splitting 236 dB! But the prize for the biggest bang for buck goes to the lesser water boatman: perhaps in protest of its diminutive size and name, it is the loudest animal for its body size (see graph; listen here: http://goo.gl/BHKhl). Fortunately, the surrounding water dissipates 99% of its mating call or it would sound like a freight train hurtling by.  Shakespeare may dismiss life as a tale told by an idiot, full of sound and fury, signifying nothing , but to a female water boatman, the call of her mate is irresistible. Especially since he generates the sound by rubbing his…ahem.. sexual appendage against his abdomen. The lesser water boatman's call is an example of runaway evolution since there is apparently no penalty paid for the price of loudness in his case.
     
    Cheers to your Ears Astonishingly, the actual displacement of molecules in the air is tiny- about  11μm or 1/7th the thickness of a piece of paper at 120 dB! Did you know that the faintest sound the human ear can detect corresponds to a displacement of air molecules by ~1.1 x 10-11 m, or 11 picometers– about 1/10 the radius of a mid-sized atom? Not only can the human ear detect vibrations with a sensitivity that spans six orders of magnitude, it can also detect sounds across nearly a 10 octave range of frequencies.
     
    Movie Soundtrack : Across The Universe + Helter Skelter (Across The Universe)
    Sounds of laughter, shades of life
    Are ringing through my opened ears
    Inciting and inviting me.
    Limitless undying love, which
    Shines around me like a million suns,
    It calls me on and on across the universe
     
    • Whacky video on how we hear: Fun Science: Sound
    • Cool Info on Sound: http://www2.cose.isu.edu/~hackmart/soundwavesIengphys.pdf

    #ScienceSunday  
  • 185 plusses - 110 comments - 58 shares | Read in G+
  • Rajini Rao2013-07-04 18:44:58
    Cellular Fireworks : To celebrate #4thofjuly .

    When a cell embarks on mitosis, the envelope around the nucleus disappears and long rods known as microtubules assemble to form a spindle. Chromosomes line up at the equator of this spindle and are pulled to opposite poles in a carefully orchestrated event driven by chemical gradients of key proteins in the cell. Images of Mitosis From L to R:

    ⁂ A protein, known as RanGTP (yellow), brings cargo to the neighborhood of the mitotic spindle (red) so it can be assembled. A gradient of this protein, spreading out from the chromosomes, is key to the perfect alignment of chromosomes along the equator of the spindle. http://goo.gl/EgQzv

    ⁂ Chromosomes (blue) are being pulled to opposite poles of four dividing cells of an embryo by the fibers of the mitotic spindle (orange). http://goo.gl/eKl62

    ⁂ Chromosomes (red) line up at the equator of the mitotic spindle (green). http://goo.gl/D1G9u

    #ScienceEveryday  
  • 228 plusses - 37 comments - 64 shares | Read in G+
  • Rajini Rao2012-12-27 00:33:07
    The Venial Vegetarian: Apologies to Asians

    • I’ve never been able to get past the mental block of eating meat. I like to think that I’m logical enough that should I be stranded on a desert island with nothing to eat but cadavers, the will to live would rule supreme. I once proffered this opinion to an evangelistic vegetarian convert and she never spoke to me again. This pragmatism served me well on a recent trip to South Korea where the concept of vegetarianism is not exactly clear. “It’s just soybean”, +Thomas Kang assured me, as I spread the homogenized paste on a cabbage leaf and took a bite, “with only a bit of shrimp”. Oops, sorry! He was all apologies as he guided me to fried and battered zucchini rounds. I savored the humble vegetable with relief and reached for a second one. Too bad it was battered fish.

    • What’s a vegetarian to do, but cook up decidedly unauthentic alternatives guaranteed to have no fish sauce (shakes fist at Thai restaurants ) or errant morsels of meat that find their way into the wok? I know I’ve looked down my sharpish nose at those generic “curries” while guiltily making my own transgressions into a foreign cuisine.  So I offer abject apologies to authentic Asian cooks everywhere, while serving up my favorite non-denominational “Asian” dinner…fast, flavorful and free of flesh.

    No Recipe Tofu: The tofu is delicate, not deep fried, in this dish. Perfect for soaking up the complex flavors in the spicy sauce.

    Baby Bok Choy Stir Fry: This is a recipe adapted from +David Crowley 's blog Cooking Chat. A feast for the eye, it combines the fresh crunch of stir fried vegetables with the roasted richness of cashew.

    Ginger Noodle Salad: From +Shinae Choi Robinson 's recipe, tossed with baby greens, sesame oil and juliened ginger. I didn't have sushi ginger ("gari") on hand so she suggested I make my own.

    For Recipes, vegetarian anecdotes and pictures of my trip to S. Korea:
    http://madamescientist.wordpress.com/2012/12/26/the-venial-vegetarian-with-apologies-to-asians/
  • 188 plusses - 198 comments - 16 shares | Read in G+
  • Rajini Rao2013-08-11 17:57:23
    See Me

    Are you ready to solve this week's science mystery picture and pick up the latest in research along the way? If you know the identity of this object, don't give it away , but share some interesting (or obscure!) fact about it. Don't be shy, let your imagination fly. 

    Hint: This object has the fastest response to light in the biological world.

    Why is this cool? A recent study revealed the unexpected finding that the initial response to light was mechanical: light triggered tiny (less than one micrometer) synchronized contractions in this array that then opened mechano-sensitive ion channels to change distribution of electric charge across the surface. This form of signaling is known as mechanotransduction and is faster than more conventional chemical signaling. Do you know of a human sense that uses mechanical signaling? 

    Image Detail: False colored scanning electron micrograph that is magnified 2,500 times if printed at 10 cm. 

    Inspiration for Title: THE WHO - See Me, Feel Me - Listening to You (1975)

    #ISeeTheWorldWithScience     #ScienceSunday  

    [Answer: http://goo.gl/JgMl3o ]
  • 183 plusses - 155 comments - 37 shares | Read in G+
  • Rajini Rao2012-04-08 16:28:20
    MIGRATION OF THE MONARCH BUTTERFLY

    Clockwork Orange: Like clockwork, each fall millions of fragile monarch butterflies from northeastern America journey 4000 km to a small area of central Mexico, to winter amidst the sacred fir groves. In the spring, the butterflies mate and begin their fluttering journey back north.While individual butterflies complete the southward journey, a succession of short lived generations make their way back north.

    Treasure trove of Navigation:This marathon is unparalleled in the insect world and approaches the sophistication of vertebrate animals, like birds. Yet, the brain of a monarch butterfly is no larger than a pinhead! They cannot learn this behavior because migrant butterflies are separated by at least two non-migrant generations. So how do they do it?

    Built in GPS: Butterflies use the sun as compass. As the sun moves east to west over the course of the day, they use an internal circadian clock to make adjustments. The clock resides in their antennae and in the brain. (If the antennae are dissected out, they continue to show cyclical changes that can be entrained to light.) Special cryptochrome proteins control these cycles. They also use magnetic fields for navigation: magnetite (iron oxide particles) that may sense magnetic fields have been found in butterflies, or they may use “light-dependent magnetoreception”.

    Genome for a King: Recently, the genome of the monarch butterfly was completely sequenced, revealing 16,866 genes spread out over 273 megabases of DNA. Genetic regulation pauses the reproduction of migrating monarchs, greatly increases life span, abdominal fat stores, cold tolerance and wanderlust! Despite being the same species, interim generations do not make the long trip. A subset of regulatory molecules (microRNAs), buried in the genetic map, are expressed differently in migratory monarchs relative to the nonimmigrant generations.

    Milkweed Specialization: Larvae feed exclusively on poisonous milkweed (Asclepias) which contain cardioactive glycosides (used to treat heart failure). The chemicals inhibit the sodium pump found in all animal cell membranes but monarch butterflies are resistant because they carry two mutations in the drug binding site of the pump. This makes them highly unpalatable to predators and lets them flaunt their gaudy colors with impunity!

    WATCH: The Pacific Grove habitat of non-native Eucalyptus attracts millions of butterflies as explained in the video in this link via +Ron K Jeffries : http://science.kqed.org/quest/video/science-on-the-spot-monarch-meetup/

    LISTEN: "Before I sink into the big sleep, I want to hear, I want to hear, the scream of the butterfly" (from When The Music's Over The Doors, 1967). The Doors - When The Music's Over (LIVE IN EUROPE 1968) This was the opening quote of a free review on Navigational mechanisms of migrating monarch butterflies found here: www.ncbi.nlm.nih.gov/pubmed/20627420. Cool science and music!

    For +ScienceSunday #sciencesunday
  • 130 plusses - 63 comments - 110 shares | Read in G+
  • Rajini Rao2012-06-12 00:29:40
    Beauty of the Butterfly Egg: Insects have been around for at least 300 million years. There are over a million species representing more than half of all known living organisms. In fact, they may account for 90% of all multicellular animals on earth

    • Yet insects abandon their young just about anywhere, leaving them to survive on their own. The secret may be hidden in their eggs: tough, yet varied, insect eggs are camouflaged or flamboyant, colorful or embellished with spines, stripes and helices. This gallery represents just one tiny fraction of diversity in the eggs: they are all butterfly eggs.

    Who knew that a butterfly egg less than 2 mm in size could be so beautiful?

    Source of scanning electron micrographs: http://ngm.nationalgeographic.com/2010/09/insect-eggs/dunn-text

    #sciencesunday #scienceeveryday  
  • 136 plusses - 82 comments - 97 shares | Read in G+
  • Rajini Rao2012-06-24 15:11:44
    YOU'RE SO VEIN: Beauty and Utility in a Leaf. You may have marveled at the intricate veins on a leaf, but did you know that the same pattern appears all over nature? The recursive looped network is found in neural nets, river deltas, insect wings and capillaries overlying a tumor.

    • Inspired by leaf venation, mathematical physicists Marcelo Magnasco and Eleni Katifori of Rockefeller University wondered if there was an evolutionary basis for the selection of high density loops in networks. They digitally dissected the pattern and used complex algorithms to derive optimal solutions for two challenges facing any transport network: resilience to damage and fluctuations in load.

    • The animated gif shows how flow of a fluorescent dye is routed around an injury (circular hole) in the main vein of a leaf, via closed loops, to reach the leaf tip. If the network had a simple tree-like branching pattern as is commonly assumed, then damage to any vein would result in tissue death downstream. Instead, the leaf is remarkably resilient to damage by insects, pathogens and the elements.

    Variations in load are also handled best by recursively nested loops. Some parts of the leaf may be lit by sunlight and exert greater demands on flow compared to shady parts. Again, hierarchically ordered trees are not as effective as topologically disordered networks seen in leaf vasculature. It took a unique partnership of physics and biology to reveal that Nature is a Master Engineer!

    ★★★  Many thanks to +Kevin Staff for donating his time and skills in making the gif for +ScienceSunday !

    Watch: Lighting up Leaves
    REF: Damage and Fluctuations Induce Loops in Optimal Transport Networks Eleni Katifori,  Gergely J. Szollosi, and Marcelo O. Magnasco
    DOI: 10.1103/PhysRevLett.104.048704

    #sciencesunday  
  • 140 plusses - 60 comments - 103 shares | Read in G+
  • Rajini Rao2012-07-17 23:59:42
    How to Write Good: I'm working on a research paper and I have to remind myself of these golden rules.   :)

    • Avoid Alliteration. Always.
    • Eschew obfuscation.
    • One word sentences? Eliminate.
    • Don't repeat yourself, or say again what you have said before.
    • The passive voice is to be avoided.
    • Avoid cliches like the plague. (They’re old hat.)
    • Foreign words and phrases are not apropos.
    • Poofread carefully to see if you any words out.
    • Don't overuse exclamation marks!!!
    • Take the bull by the hand and avoid mixing metaphors.
    • Be more or less specific.
    • Understatement is always best.
    • Who needs rhetorical questions?
    • And always be sure to finish what

    More: http://goo.gl/eDTuP
  • 159 plusses - 100 comments - 73 shares | Read in G+
  • Rajini Rao2013-08-13 11:43:07
    Waterproofin' with Hydrophobin

    ● Did you know that on average, there are between 1,000 and 10,000 fungal spores in every cubic meter of air? You breathe between 10 and 20 cubic meters of air every day, and every breath contains between 1 and 10 spores, of many different types. 

    ● These spores have a secret to staying dry and airborne: they are covered by a unique coat protein called hydrophobin, that repels water, but allows gases to exchange, like a botanical GORE-TEX. One side of the layer is water-loving, and the other is as repellent to water as Teflon or paraffin.

    ● Molecules of hydrophobin self-assemble to form a "rodlet" pictured in the inset, that has surprising similarity to amyloid fibrils found in plaques in the brains of Alzheimer's patients. So not only could this protein lead to better design of nanoparticles (e.g., for drug delivery), but it may help understand a debilitating disease. 

    Image: The fungus Emericella nidulans  (http://goo.gl/OivWNE) is covered by rodlets of the protein hydrophobin (inset; http://goo.gl/Ca1JZz ) which makes the spores waterproof.

    REF (open access): Hydrophobins: unique fungal proteins Bayry et al. (2012)  http://goo.gl/gpzAbA

    #ScienceEveryday  
  • 215 plusses - 59 comments - 56 shares | Read in G+
  • Rajini Rao2014-01-11 17:01:46
    Science Mystery Pix

    Art or Nature?: This beautiful image reminds me of the art of Van Gogh: Willows at Sunset (http://goo.gl/E0rYPo), perhaps? But it's actually a photomicrograph of an insect part. Can you guess what it may be? Hint: it's useful during aquatic sex :) 

    Rheinberg Illumination: This image was colorized using a form of microscopy invented in 1896 by Julius Rheinberg. Quite simply, a two colored filter, usually cut from sheets of acetate, is placed in front of the light source. One color makes up the background while the other is diffracted by the object under study. It's a cheap and creative way to bring art into science! A nice explanation can be found here: http://www.cellsalive.com/enhance1.htm

    Photo credit: Spike Walker / Wellcome Images

    #ScienceEveryday    #ISeeTheWorldWithScience  
  • 220 plusses - 72 comments - 43 shares | Read in G+
  • Rajini Rao2013-04-21 10:53:03
    The Brain on Art

    ◑ Art and Science combine in the incipient field of Neuroaesthetics. In 1900, Alois Riegl argued that art is completed by the perceptual and emotional involvement of the viewer. This view aligned art history with psychology. It followed that a work of art is inherently ambiguous and each person who sees it has a different interpretation. Your brain is a creativity machine that obtains incomplete information from the outside world and completes it.

    ◓ Some of this creative process has a structural basis, driven by the way the brain develops. Thus, the ability to be aesthetically moved is universal and common brain areas are activated across all humans. Other areas light up differently, reflecting the wide variety of emotional states associated with viewing art.

    Assessing Aesthetics:  In one experiment, Oxford University researchers recorded blood flow in the brain (by fMRI) of subjects who saw a series of Rembrandt paintings that were labeled authentic or copy. Actually, the paintings were mixed up so that some were labeled incorrectly. But the visual areas of the brain that lit up were the same, whether the painting was real or a good copy - not surprising, since the average person would not be expected to tell them apart. What was surprising was that the label of authenticity triggered areas associated with perceptions of reward, pleasure and monetary gain.  The paintings thought to be inauthentic generated strong spikes in working memory, as the people were actively trying to detect the flaws in the presented image. Our aesthetic judgements are subject to a variety of different influences that may be inaccessible to direct introspection but are revealed by neuroimaging. Did you know that changing the price label on wine alters our taste perception? (http://goo.gl/fJ7E1)

    ◕ Image Source: http://www.cell.com/cell_picture_show-weaving
    ◔ Story: http://www.wired.com/wiredscience/2011/12/how-does-the-brain-perceive-art/

    #ScienceSunday  
  • 194 plusses - 54 comments - 66 shares | Read in G+
  • Rajini Rao2012-05-29 16:38:01
    Friends, we need your help!

    Many of you know +Konstantin Lamanov —well known on Google+ in his own right and the creator of a popular series of G+ pages.

    Konstantin’s mother, Tatyana Makovoz, is seriously ill with cancer in Ukraine, and the family has exhausted its financial resources in helping her. That’s where we come in—and we’re hoping you’ll join us in contributing to raise funds. Between us, we have tens of thousands in our circles. It shouldn’t be too hard to reach our goal of $10,000. Please share this post and donate —no amount is too small to help.

    To contribute: http://www.osvita.org.ua/pages/help_share_en.html

    From the G+ Pages Team:
    +Rajini Rao +Margie D Casados +Rich Pollett +Annette Marin +Adarsh vijay +Rahul Roy +Alex Anderson +Milad Farjadian +Alexander Panov +Sergei Agarkoff +Andrew Obrazcov +Светлана Свет +Peter Lindelauf
    #FundForTatyana
  • 55 plusses - 40 comments - 156 shares | Read in G+
  • Rajini Rao2013-01-04 13:26:08
    Shaken, Not Stirred: The Science behind Bond's Martini

    Moderate alcohol consumption reduces risks of developing cardiovascular disease, stroke, and cataracts. As Mr Bond enjoys perennial robust health, scientists investigated whether the mode of preparing martinis has an influence on their antioxidant capacity.  Reporting in the British Medical Journal, they concluded that 007 was not only astute in matters of clandestine affairs both personal and international, he also had keen scientific and medical insights.

    Anti-Aging Antioxidants: Wonder why 007 looks so young? Shaken martinis were more effective in deactivating hydrogen peroxide than the stirred variety, and both were more effective than gin or vermouth alone (0.072% of peroxide remaining for shaken martini, 0.157% for stirred vs. 58.3% for gin and 1.90% for vermouth). More data: http://goo.gl/N44xc

    Daddy Cool? When the martini is shaken, not stirred, tiny bits of ice flake into the drink, and as they melt, the drink is distinctly colder. It's also more dilute, so perhaps Bond was going easy on the alcohol to keep his head clear?

    Vespers to Esters: Water, in the form of ice, breaks down the esters to release aromatics. "Shaking will better remove very volatile organic compounds from the liquid" explains George Christou of the University of Florida, "and air oxidizes some of the other organic compounds present, affecting its taste." This is akin to letting red wine breathe before you serve it.

    Recipe: Vesper Cocktail, from James Bond in Ian Fleming's 1953 book Casino Royale.  "Shake it very well, until it's ice cold, then add a large thin slice of lemon peel. Got it?"

    - 3 oz Gordon's Gin
    - 1 oz Stoli Vodka
    - 1/2 oz Kina Lillet

    Watch: Dashing Bonds delivering the famous one liner over the years. Vodka Martini, Shaken, Not Stirred

    Reference: Shaken, not stirred: bioanalytical study of the antioxidant activities of martinis. Trevithick et al., 1999. British Medical Journal 319:1600

    Happy Birthday to our own Mr. Bond, +Gnotic Pasta ! #DashingDansVan  
  • 167 plusses - 127 comments - 48 shares | Read in G+
  • Rajini Rao2012-09-11 23:42:00
    Fish With Transparent Head Filmed 
    This barrel eye fish is not going to win any beauty prizes. But it surely deserves admiration for its enormous telescoping eyes, housed in a transparent head that functions as a muscle-driven lens to scavenge what little light penetrates the inky ocean depths. The huge green lenses points to a retina with exceptional density of rod cells, packed with the light harvesting protein rhodopsin.  Cone cells, that see color, are absent. Those two tiny openings on either side of its mouth? They are nostrils .
    The fish spends most of its time motionless, eyes directed upwards to catch the shadow of prey emitting faint bioluminescence.

    #scienceeveryday when it's not +ScienceSunday .
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  • Rajini Rao2013-03-16 15:07:56
    Meet the Erythrocyte

    Red blood cells take up 45% of your blood volume and circulate about once in 20 seconds, carrying vital oxygen to every nook and cranny of your body. Did you know that ~2.4 million of these are produced each second? That's because they have a short life span of only about 120 days.

    Please squeeze me: The image shows a red blood cell squeezing through a tiny capillary: to accomplish this maneuver, the red cell sacrifices its nucleus and mitochondria to become a flexible, biconcave disk. In the inset, is a deformed red cell from a patient with sickle cell disease shown next to a normal cell. A single mutation in hemoglobin, the oxygen carrier of red blood cells, causes the proteins to clump giving the cells their characteristic sickle shape. The deformed cells block capillaries and burst more easily, surviving only 10-20 days. 

    Heterozygote advantage: Given the severe health complications from sickle cell disease, why does the mutation persist in some populations? You might expect that negative selection against affected individuals would have eliminated the mutation. It turns out that carriers of the mutation (who have one normal copy and one mutated version of the gene), have mild sickling of their red blood cells which also makes them more resistant to infection by the malarial parasite. In fact, sickle cell disease is more common in areas where malaria is endemic. 

    Another installment of an  #excyting  series on cells. This one is for +Chad Haney who celebrates his birthday today and is my fellow conspirator in science outreach on Google Plus. Chad worked on generating a blood substitute as a graduate student. #HappyBirthdayChad   #HappyBirthdayMrMRI   #ScienceEveryday   #ScienceSunday  

    Image: www.visualphotos.com
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  • Rajini Rao2013-07-21 16:34:34
    Going Rogue : How does a cancer spread to become metastatic?  
    Why do cells that are tightly packed or neatly arranged in rows (epithelia), come loose and become insidiously mobile? The answer lies in a basic developmental process known as EMT, short for epithelial to mesenchymal transition

    ❑ During EMT, cells no longer know which way is up (i.e., lose their polarity), break off their cell-cell junctions and extend pseudopodia or foot-like processes that help them move. In the image below, colon cancer cells were caught in the act of rearranging their junctional proteins (in red and green) to become amorphous, drug-resistant and invasive. Even more dangerous, these cells acquire stem cell properties, allowing them to seed new cancers. In short, cells lose their mature, differentiated form and recapitulate their origins. 

    ❑ But EMT, and its reverse process MET, are normal features of embryo development, leading to formation of the neural tube, heart valve and other organs. Also, during wound healing, skin cells at the edge of the wound undergo EMT, reverting back by MET after the wound is closed. Understanding what triggers these changes, and how they may be controlled, is key to cancer therapy. 

    ❑ This explanation is in response to the more sensationalistic title, New theory uncovers cancer's deep evolutionary roots , shared on G+. The theory "promises to transform the approach to cancer therapy, and to link the origin of cancer to the origin of life and the developmental processes of embryos". Choose between breathless science (http://goo.gl/yDsys) or the rational explanation here :)

    Wiki entry for EMT: http://goo.gl/2U806

    Reference (open access): Chronic oxaliplatin resistance induces epithelial-to-mesenchymal transition in colorectal cancer cell lines. Yang et al. http://www.ncbi.nlm.nih.gov/pubmed/16857785

    #ScienceSunday  
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  • Rajini Rao2012-01-25 11:42:56
    Do you use the Oxford Comma? Also known as the serial or Harvard comma, it is added after before the last conjunction in a series of three or more items.

    "I thank my parents, Ayn Rand, and God" versus "I thank my parents, Ayn Rand and God". Proponents argue that not only is the latter absurd, Ayn Rand would have rejected such a collaborative arrangement with God of all people ;)

    Whatever your thoughts on this, I do hope you don't use a double space after a period?
  • 118 plusses - 128 comments - 75 shares | Read in G+
  • Rajini Rao2013-11-24 14:53:16
    Good Fat is BAT!

    Beige, Brite, Brown or White: If you thought all fat was white and wobbly, think again. Some fat depots are colored brown because they are rich in mitochondria- powerhouses of energy loaded with iron-containing cytochrome proteins (bottom panel in image). Beige/Brite fat cells are in between white and brown fat. Human infants have stores of this brown adipose tissue (BAT), up to 5% of their body weight, between their shoulder blades and in their neck, colored green in the MRI scan (top image). Hibernating animals stock up on brown fat too. Why? Because brown fat generates heat.

    The Heat is On: Our mitochondria are factories that extract energy from food and store it in the form of a proton (Hydrogen ion) gradient across their borders. Like water cascading down a fall turns a turbine to generate electricity, this gradient of protons can run downhill through the ATP synthase, propelling it like a motor to capture energy from food by making a chemical compound called ATP. But if these protons ran downhill without doing any work, their potential energy would be lost as heat. The mitochondria in brown fat do just that. They make an uncoupling protein that short circuits the proton gradient to generate heat instead of ATP. This form of thermogenesis is important to newborns and hibernating animals who can't use the shiver reflex to give off heat from their muscles.  

    Better with BAT: Since brown fat burns calories, more BAT could counter obesity, cardiovascular disease and Type 2 diabetes. But adult humans lose most brown fat during adolescence. Fortunately, new studies show that we do have some, mostly deep inside our neck (lower image). One approach to increasing BAT is exposure to cold! Brrr ... if that sounds uncomfortable, stem cells may boost your BAT. Curiously, brown fat cells share a common lineage, not with white fat cells, but with muscle cells. Recent research has revealed the presence of adult stem cells that can be coaxed into active BAT. The hope is to induce these cells to form calorie-burning brown fat in humans. Now that's a healthier browning than a tan!   

    ◑ Images and Refs: (1) Evidence for two types of brown adipose tissue in humans. 
     http://www.nature.com/nm/journal/v19/n5/full/nm.3017.html
    (2) How brown is brown fat? Depends where you look. Nedergaard and Cannon Nature Medicine 19, 540–541 (2013)

    #ScienceSunday
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  • Rajini Rao2013-02-27 23:19:16
    Fat Cell

    Meet the adipocyte or fat cell, the first in an occasional series of #excyting cell types. Each cell, marked by the blue nucleus, is loaded with fat droplets stained in green. 

    Why we need fat: Adipocytes have three important jobs: they store energy in the form of fat, they secrete hormones and they respond to insulin to meet the immediate energy needs of our bodies. Obese people who carry out these three functions are metabolically healthy and actually have 38% lower mortality risk. If fat is stored elsewhere, it leads to metabolic disease.

    Good fat, bad fat, white fat, brown fat: Not all fat cells are equal. While white fat stores energy, brown fat burns energy to produce heat. Babies and hibernating animals use brown fat to keep warm. The brown color comes from being packed with iron-rich mitochondria. In brown fat, these powerhouses are "uncoupled": they use energy from fat to pump protons across their membrane but the protons run backwards in a wasteful exercise in futility that generates heat.

    Fat is plastic: white fat cells can convert to brown fat by a process induced by cold temperatures. This is a good thing: animals with more brown fat are more resistant to diabetes and obesity.

    Fat cells are constant: It is generally believed that the number of fat cells is nearly constant, beyond childhood. Rather, it is the size of the cell that changes. When mature, an adipocyte may be 10 or 20 times its original size.


    Image: 3T3-L1 derived adipocytes stained for lipid droplets (green) and DNA (blue). Finalist, GE Healthcare cell imaging competition, 2012 ▶ http://goo.gl/hkzBE Inset, colored scanning electron micrograph of a fat cell. Most of the adipocyte's volume is taken up by a large lipid (fat or oil) droplet. Fat accumulation starts with a few small lipid droplets which coalesce to make one large droplet. Magnification: x10,000 when printed at 10 centimetres wide.  ▶ http://goo.gl/sZ6hp

    #ScienceEveryday
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  • Rajini Rao2012-01-15 15:28:43
    Two to Tango: The Calcium Pump

    A molecular dance: Powered by ATP (near the red domain), calcium ions (yellow spheres) flow through this transport protein to generate huge chemical gradients, 10,000 times more concentrated on one side of the membrane than the other. As a result, when a signal arrives at the cell membrane, ion channels open and calcium ions can rush down their chemical gradient in waves (e.g., Intracellular Calcium Ion Flux of Tissue Engineered Cardiac Model). Calcium binds to sensor proteins which then signal a variety of events, ranging from muscle contraction, gene regulation, secretion of insulin, release of neurotransmitter, cell division and movement.

    History: In 1883, Sidney Ringer was studying the contraction of isolated rat hearts suspended in a solution made from London tap water. The heart beat perfectly. When he replaced tap water with distilled water, it stopped. Ringer had serendipitously discovered that calcium in the ‘hard’ water was a critical messenger for muscle contraction, in a way that had nothing to do with its role in bones and teeth.

    Family relations: The first ion pump of this type (P-type ATPase) was the sodium pump, discovered by Danish scientist Jens Skou in 1957, for which he won the Nobel prize. There are 36 variants in the human genome and they pump different ions such as calcium, protons, potassium and copper. They share a common mechanism in which the phosphate group of ATP becomes chemically attached to the pump protein in each cycle, transiently, to form a phosphoenzyme intermediate (hence the term, P-type).

    Pumps in Medicine: The sodium pump is a target for cardiac glycosides (derived from foxgloves and milkweed) used in treating heart failure. The gastric proton pump is the target of blockbuster drugs used for controlling stomach acidity. (See: "Proton Pump Inhibitors" PPI animation for Perrigo Company) Calcium pumps are being tested in gene therapy and as targets for cancer.

    Google+ Collaborations: ★ Many thanks to +Kevin Staff ★ who generously donated his time to make this animated gif from this molecular simulation: http://www.pumpkin.au.dk/research/download-gallery/

    +Konstantin Makov suggests that you watch the Calcium Pump dance while listening to Libertango, because the ATPase reminds him of a couple dancing while being pierced with the arrow of amore (calcium!). Thank you Konstantin for the charming suggestion! ♫ Astor Piazzolla - Libertango

    For #ScienceSunday hosted by +Allison Sekuler and +Robby Bowles .
  • 117 plusses - 22 comments - 114 shares | Read in G+
  • Rajini Rao2014-01-30 23:04:24
    Homo aquaticus: The Science of an Underwater Gill

    In 1962, underwater explorer Jacques Cousteau predicted the arrival of Homo aquaticus: people surgically equipped with gills who could live and breathe in any depth for any amount of time without harm. Lately, there has been a lot of buzz about Triton, a conceptual gill (http://goo.gl/pWkd5k) that supposedly could allow humans to breathe underwater. There are many reasons why this device is still in the realm of science fiction. But first, it's helpful to understand how some animals breathe air underwater. 

    Breathe, Breathe in the Air: Like us, insects breathe oxygen from air, using a system of canals connected to the outside by breathing holes or spiracles. So how do aquatic insects survive submerged underwater, often for their entire lives? Mosquito larvae develop tiny snorkeling tubes, called siphons, that poke out of the water for regular refills. Others, like mayflies and damselflies, develop biological gills that extend into the water to extract oxygen by diffusion. The champion for ingenuity, however, is the diving beetle which carries a bubble of water tucked under its body, seen as a silvery sheath in the photograph. The air bubble is a short term supply of oxygen, that is replenished from the surrounding water based on a few simple physical principles that are fun to consider!

    Love is like Oxygen: Water contains dissolved oxygen, reaching up to 5% in volume in icy-cold streams, but much less than the 20% found in the atmosphere. As oxygen is consumed by the insect, it creates a partial pressure difference inside the air bubble.  This is "corrected" by dissolved oxygen that diffuses in from the water.  There is a lot of unused nitrogen in the air bubble, 80% by volume, which is free to diffuse out , also creating a similar partial pressure deficit.  Because there is very little dissolved nitrogen present in water (it has lower water solubility than oxygen), some of the nitrogen's partial pressure deficit is "corrected" by oxygen diffusing in, enriching the insect's air supply.  So as long as the rate of oxygen diffusing in keeps up with the rate at which it is consumed by the insect, all is well. Unfortunately, the surrounding pressure of the water can shrink the size of the bubble over time, reducing the surface to volume ratio and hampering gas exchange. That's why some insects make the occasional trip to the water surface, to refill their air bubbles. For those insects that don't have this option, a plastron is the answer. 

    What the Fakir?: A plastron is a special array of rigid, closely-spaced hydrophobic hairs (setae) that create a fixed "airspace" next to the body.  Air trapped within a plastron operates as a physical gill (just like air in a bubble) but this airspace cannot shrink in volume because a double layered fortress of setae prevents encroachment of surrounding water.  Think of the analogy of a fakir lying on a bed of nails: while one nail can puncture through his skin, lying on many nails effectively distributes his body weight so that the skin, like the surface of water (inset images below), is not broken. Also, the setae do a good job of repelling water using the lotus effect covered in an old post (http://goo.gl/yW7QpC). 

    Triton or not Triton?: Back to the beginning, will a physical gill work for humans? Humans need a lot more oxygen than beetles, so enormous surface areas will be needed to extract oxygen from water. Too much or too little oxygen in the air we breathe can be toxic. Still, a terrier named Muggins survived a 3 hour dip in the Mississippi river using articificial gills. Check out the story (http://goo.gl/xdJeQd) and tell me if you think  Homo aquaticus  will soon be in a pool near you!  

    Images: Diving beetle by Ernie Cooper (http://goo.gl/EWMwjx); Inset http://goo.gl/ci28mS

    #ScienceEveryday  
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