Category: Favourites

Multicellularity Driven by Bacteria

  • Venue: Science Magazine
READ MORE
F1.smallMONTREAL, CANADA—When taking a dip this summer you will probably swallow tens, possibly hundreds, of microscopic plankton called choanoflagellates. These common organisms have led to an uncommon insight into how multicellular organisms might have evolved. Bacteria can prompt single-celled choanoflagellates to divide into multicellular versions of themselves, University of California (UC), Berkeley, biologist Nicole King reported last week here at the 71st annual meeting of the Society for Developmental Biology. King hopes the work will prompt biologists to look more closely at the role of microorganisms in the evolution of multicellularity.

To the untrained eye, choanoflagellates look like animals. But they are less complex—the closest living relatives of animals but on an older branch of the tree of life. As such, these organisms can provide clues about what early animals looked like and can help reconstruct the events from more than 600 million years ago that led to the incredible diversity of the animal kingdom.

To investigate the transition to colony life, King decided to sequence the genome of a colony-forming choanoflagellate and compare it with the genome of a unicellular individual. But before sequencing, she asked undergraduate Richard Zuzow to purge the sample of everything but the plankton itself. When Zuzow added antibiotics to get rid of any bacteria, the choanoflagellate colonies disappeared. At first, “I didn’t believe him,” King recalls. But with repeated tests, she became convinced that “the bacteria are the important part of the [multicellular] story,” she says

:: Read more here (behind pay-wall) or download pdf here ::

Ancient horses’ spotted history reflected in cave art

  • Venue: BBC
READ MORE

Scientists have found evidence that leopard-spotted horses roamed Europe 25,000 years ago alongside humans.

Until now, studies had only recovered the DNA of black and brown coloured coats from fossil specimens.

New genetic evidence suggests “dappled” horses depicted in European cave art were inspired by real life, and are less symbolic than previously thought.

The findings are published in the Proceedings of the National Academy of Sciences.

Horses, which were the most abundant large mammal roaming Eurasia 25,000 years ago, were a key component of early European diets.

So it is not surprising that the cave art of this time had a certain equestrian flair – horses make up 30% of the animals depicted in European cave paintings from this era.

Biologists, interested in the diversity of European animals before the last Ice Age, are interested in how accurately these early artistic impressions portrayed the colouring of the horses that lived alongside the ancient humans.

“It was critical to ensure that the horse depictions from the cave paintings were based on real-life experiences rather than products of the imagination,” explained lead author Arne Ludwig from The Leibniz Institute for Zoo and Wildlife Research in Berlin.

In previous work, Dr Ludwig, and his colleagues, recovered only the DNA of black and brown coat colours from the prehistoric horse bones.

But the dappled coats of the 25,000 year horses depicted at the Pech Merle cave complex in France convinced the team to take a second look.

Fur coats

By revisiting the fossil DNA of 31 horse specimens collected from across Europe, from Siberia to the Iberian Peninsula, the researchers found that six of the animals carried a mutation that causes modern horses to have white and black spots.

Of the remaining 25 specimens, 18 were brown coloured and six were black.

Dr Ludwig explained that all three of the horse colours – black, brown and spotted – depicted in the cave paintings have now been found to exist as real coat-colours in the ancient horse populations.

The researchers say that these three colours probably provided enough variation for humans to create the diversity of coat colours and patterns seen in modern horses.

The domestication of horses, which produced modern breeds, is thought to have begun about 4,600 years ago in the steppe between modern Ukraine and Kazakhstan.

:: Read original here ::

Is It Folly to Take Folic Acid?

  • Venue: Science Magazine
READ MORE

For mothers-to-be, doctors worldwide advise taking a folic acid supplement. That’s because pregnant women with a deficiency of this vitamin have an increased chance of giving birth to a baby with serious birth defects, such as spina bifida and anencephaly. Yet a new mouse study shows that folic acid supplementation can itself sometimes increase the risk of birth defects or even cause the death of embryos. Experts caution, however, that the unexpected rodent results are too preliminary to require an immediate change in medical practices until more is known about how the vitamin influences development.

People typically obtain folic acid, or folate, from consuming leafy vegetables, but not everyone gets enough from their diet, particularly pregnant women. The vitamin plays a key role in the development of the neural tube, the embryonic region that gives rise to the spinal cord and brain.

Evidence from randomized clinical trials has shown that babies born to women who double their recommended daily dose of folic acid are between 40% and 50% less likely to have birth defects of the spine, skull, and brain. As a result, the United States has fortified most of its grains with this vitamin since 1998, and a handful of other countries have followed suit.

But just how the vitamin influences embryonic growth remains a mystery. So developmental biologist Lee Niswander of the University of Colorado, Denver, set out to investigate folic acid supplementation in mice genetically predisposed to giving birth to embryos with neural tube defects. She and her colleagues fed five such strains of mutant mice food containing either 2 or 10 mg of folic acid per kilogram, which created a range of blood levels of the vitamin equivalent to that in the U.S. population.

To the surprise of the researchers, in three of the five strains, the extra folic acid seemed to worsen the severity of birth defects rather than remedy them. In one of the mutant lines, dubbed L3P, eating the higher folic acid diet long term increased the chance that young were born with neural tube defects from 20% to 60%, the group reports in the 15 September issue of Human Molecular Genetics. And for another strain, Shroom3, many of whose embryos don’t naturally survive until birth due to their genetic problems, eating the higher folic acid food significantly increased the percentage of lost embryos.

Niswander says it is clear that folic acid is good for human fetuses, but the new study makes her wonder whether high levels of the vitamin may be harmful in some circumstances. Still, she stresses that more data are needed before any serious reconsideration of how much folic acid to recommend for impending mothers.

Roy Pitkin, a retired University of California, Los Angeles, researcher who specialized in pregnant women’s nutrition and chaired an Institute of Medicine panel that in 2000 reviewed folic acid’s health effects also cautions against a rush to judgment: “It would really be throwing the baby out with the bath water to say that because of this one mouse study, we are going to question the food fortification.”

Especially, he says, because we know that species differ considerably from each other when it comes to birth defects. He offers the example of thalidomide—a drug given to pregnant women in the 1950s to cure morning sickness—that causes severe human birth defects but that is perfectly safe in rats.

Neuroscientist Elizabeth Grove of the University of Chicago studies how the mammalian brain develops and echoes this concern. She warns that researchers have found hundreds of mutations that cause birth defects in mice but that so far don’t seem to produce the same problems in humans. The effects of folic acid may also be species specific, she says.

:: Read original here ::

Loosing the Louse on Europe’s Largest Invasive Pest

  • Venue: Science Magazine
READ MORE
Science-2011-Carpenter-781

Don’t be duped by its delicate pale flowers; Japanese knotweed can be a sinister plant. Native to eastern Asia, Fallopia japonica was intentionally introduced into gardens in Europe 200 years ago by fans of its attractive blooms; from there it spread to North America. What makes this invasive weed so menacing is its ability to grow through solid concrete foundations, forcing contractors to abandon infested building sites. In England alone, about a half-million homes are uninsurable, and in the United Kingdom, damages and removal cost $288 million a year.

Now the British government has taken a bold step to solve this knotty problem, and North American researchers might not be far behind. Last week, after more than 5 years of research into the matter and an initial pilot trial, the United Kingdom approved the widespread release of one of the plant’s natural enemies. While there are dozens of biological controls already in use against insect pests, this is the fi rst offi cially sanctioned release of one against a weed in the European Union. “This is an extremely important step. … If this is successful, it will really open the doors and open the minds of people for this control method in Europe,” says weed biocontrol specialist Hariet Hinz of CABI Europe in Delemont, Switzerland, a nonprofi t agricultural research organization.

:: Read original here ::

Profile: Jon Heras, Seeing Is Believing

  • Venue: Science Magazine
READ MORE

The cold sea fogs of Scotland have inspired many artists, but as a boy Jonathan Heras saw instead the North Sea oil fields and the prosperity they brought to his hometown of Aberdeen. So he became an engineer, earning a Ph.D. in chemical engineering from the University of Cambridge in the United Kingdom. But today, he makes his living as a graphic artist, and although his art is not inspired by Scotland’s scenery, his renderings of science are no less vivid than its raw and boisterous coast.

“Getting things to look authentic is the real trick. You need to add dirt and imperfections”. — Jonathan Heras

From the science behind the Large Hadron Collider experiment at CERN, the European particle physics lab; to the construction of the Bloodhound SSC, a car capable of speeds above 1000 miles per hour; to a portrait of a microscopic bacteriophage that recently received an honorable mention in Science magazine’s Visualization Challenge, Heras’s illustrations and animations depict a wide range of scientific concepts.

Heras, now 30, first explored animation in his early 20s when he and a university friend, Ivan Vallejo, directed a satirical stop-motion movie called The Polos of Death. Recorded on location in a college dorm room, the film features the action figure Boba Fett, from Star Wars, battling to the death a tribe of bloodthirsty Polos — a peppermint sweet — set to a soundtrack of Burt Bacharach and the Bee Gees. The film was “just a bit of fun,” Heras says, but he enjoyed the process of animation because it required him to be meticulous — a skill he seems to possess naturally and one he came to rely on during his Ph.D.

During his graduate studies in Cambridge’s Department of Chemical Engineering and Biotechnology, Heras looked at the flow patterns of liquid and gas through a catalytic converter using magnetic resonance imaging. His research subject proved difficult to convey to an audience at conferences, so Heras made short animated films of his flow-pattern data. “People don’t always remember what you are doing in terms of your research, but they do seem to remember you as the guy with the flashy animation,” he says, laughing.

Heras found his graduate work “quite frustrating,” he says. “The graphics were much more rewarding.” And so in his spare time he took on side projects that relied on his creative hobby. In one project, he was commissioned to make a safety video for his department. “We were surprised at how sophisticated a film he turned out,” says Mick Mantle, a chemist at Cambridge. “It became compulsory viewing for all new engineering students.” Heras “was a very, very bright student,” Mantle says, “but he preferred the image analyses side of things.”

In spring 2006, a few months from the end of his Ph.D., Heras set up as a freelance illustrator under the name Equinox Graphics, specializing in scientific visualizations. “Working from home was quite a struggle; you find that you work all sorts of crazy hours. I often watched TV at 5 in the morning because that was when I was up and working.”

Within 3 years he had enough work to need help, so he enlisted the animation skills of his friend James Waldmeyer, whom he knew from his undergraduate days. In 2009, he and Waldmeyer moved out of Heras’s spare room and into new premises on the outskirts of Cambridge. Heras still likes his home comforts, though, and sometimes works in his slippers.

Heras’s work relies on large amounts of computer processing power. He splits his workload across a network of 10 computers; even so, a frame of animation can take an hour to process. “If you have 25 frames per second and a minute of animation, it quickly adds up,” he says. The cost of all that computing power adds up too, and that affects his bottom line. “I know I could definitely earn more as a chemical engineer, but I wouldn’t have the job satisfaction I have,” he says.

Heras believes that keeping his work varied is key to staying successful. “It would be easy to just churn out many of the same images, tweaked to suit a particular client, … but this would be boring.” Instead, Heras picks projects he knows little about. He has animated a BMX trick that explains the basic physics of flying through the air on a bike (for the 100th anniversary celebration of Einstein’s Annus Mirabilis papers in 2005); a short documentary for the European Space Agency’s mission to orbit the sun with a satellite; a clip of an operation in which a device was inserted into a human vein to prevent a serious blood clot; and many more.

Heras’s first step toward creating an image is to learn as much as possible about the subject. “We start by researching on Wikipedia, and then we go to more detailed and accurate sources to fine-tune our understanding,” he explains. “We try to make [the] gulf of knowledge between us and the scientists as small as possible.” Heras and his partner come up with ideas and then meet with the client. Once they agree on the scope of the work, the real work begins. “Some of the images take a week to create,” he says.

Heras says he relies on what he already knows about science. However, the work requires some artistic license. All illustrators have to make these sorts of calls, he explains: “filling in the colors, the textures, the speeds that things move.” Heras cites the award-winning animation called The Inner Life of the Cell, made by Harvard University to take its biology students on a journey through a cell’s microscopic world. “It’s an amazing visual,” Heras says, but the space inside a real cell “is jam-packed with all sorts of things that are buzzing around. … It is not this vacuous space where you can see everything clearly,” as it is in the video. The video’s illustrators chose to simplify the cell so that viewers could more easily see what’s going on. Sometimes, he says, such editorial decisions are necessary, but they can be hard to make.

On the other hand, scientific illustrators must always be careful to make sure things don’t look too clean and pure, Heras says. “Getting things to look authentic is the real trick,” he says. “You need to add dirt and imperfections.” Knowing how to do that takes time, especially if you are self-taught. Heras says he picked up tips like these — indeed, most of what he knows about the craft — by reading blogs and online forums.

After so many years of formal education, earning a living from skills learned online and picked up in a college dorm room might seem strange. He says he still hasn’t completely convinced his parents that his career choice is a good one. But he hopes that in time they’ll come around, since he’s making a living and creating interesting things. Just as in his illustrations, seeing is believing.

:: Read original here ::

Does Bird Flu + Swine Flu = Superflu?

  • Venue: Science Magazine
READ MORE

What do you get if you cross bird flu with the 2009 pandemic human virus, widely known as swine flu? Unfortunately, the answer isn’t funny. A new study predicts that swapping genes between the avian and human influenza viruses may result in an even more dangerous flu.

The human influenza virus H1N1 that caused the 2009 flu pandemic, and H9N2, an avian influenza virus that is endemic in bird populations in Asia, are close cousins—close enough that they can swap genes if they find themselves in the same cell, resulting in new viruses that are a patchwork of the parent strains. Scientists suspect that some gene combinations may result in a particularly potent form of flu and ignite a pandemic in humans. But because these viruses are more likely to meet in the lungs of an Asian chicken farmer than under the nose of a virologist, researchers find it difficult to predict which gene combinations might be the most virulent and contagious.

So instead of waiting and seeing, researchers have played matchmaker and thrust the two viruses together in a test tube. A team in China generated 127 hybrid viruses and injected each one into lab mice. More than half of the hybrids were as good as their parent strains at infecting the mice, and eight of them proved to be more pathogenic, the team led by Jinhua Liu of the China Agricultural University in Beijing reports online today in the Proceedings of the National Academy of Sciences.

“These are important experiments”, says virologist Peter Palese of Mount Sinai Medical Center in New York City, who was not involved in the work. The viral hybrids that the Chinese team has identified are the ones that scientists might want to watch out for worldwide, he says. If these strains were recognized early, governments could launch a speedier response.

Creating highly virulent viruses in the lab is controversial, says virologist Ab Osterhaus of the Erasmus University Medical Center in Rotterdam, the Netherlands. “[But] I don’t think we should shy away from these experiments. … The more information we have, the better,” he says.

He explains, however, that the hybrids that are the most virulent in mice will not necessarily be the most dangerous in humans, nor the most contagious. “Mice mirror, to a certain extent, what happens in humans,” he says, but they are not perfect model animals. Liu agrees. He plans to investigate how contagious his new viral blends are in guinea pigs and ferrets—animals whose respiratory system better reflects our own feverish battle with flu.

:: Read more here ::

May the Best Analyst Win

  • Venue: Science Magazine
READ MORE
LAST MAY, JURE ŽBONTAR, A 25-YEAR-OLD computer scientist at the University of Ljubljana in Slovenia, was among the 125 million people around the world paying close attention to the televised finale of the annual Eurovision Song Contest. Started in 1956 as a modest battle between bands or singers representing European nations, the contest has become an often-bizarre affair in which some acts seem deliberately bad—France’s 2008 entry involved a chorus of women wearing fake beards and a lead singer altering his vocals by sucking helium—and the outcome, determined by a tally of points awarded by each country following telephone voting, has become increasingly politicized.

Žbontar and his friends gather annually and bet on which of the acts will win. But this year he had an edge because he had spent hours analyzing the competition’s past voting patterns. That’s because he was among the 22 entries in, and the eventual winner of, an online competition to predict the song contest’s results.

The competition was run by Kaggle, a small Australian start-up company that seeks to exploit the concept of “crowdsourcing” in a novel way. Kaggle’s core idea is to facilitate the analysis of data, whether it belongs to a scientist, a company, or an organization, by allowing outsiders to model it. To do that, the company organizes competitions in which anyone with a passion for data analysis can battle it out. The contests offered so far have ranged widely, encompassing everything from ranking international chess players to evaluating whether a person will respond to HIV treatments to forecasting if a researcher’s grant application will be approved. Despite often modest prizes—Žbontar won just $1000—the competitions have so far attracted more than 3000 statisticians, computer scientists, econometrists, mathematicians, and physicists from approximately 200 universities in 100 countries, Kaggle founder Anthony Goldbloom boasts.

And the wisdom of the crowds can sometimes outsmart those offering up their data. In the HIV contest, entrants significantly improved on the efforts of the research team that posed the challenge. Citing Žbontar’s success as another example, Goldbloom argues that Kaggle can help bring fresh ideas to data analysis. “This is the beauty of competitions. He won not because he is perhaps the best statistician out there but because his model was the best for that particular problem. … It was a true meritocracy,” he says.

:: Read full article here ::

Don’t Take That Cookie!

  • Venue: Science Magazine
READ MORE
Stop it! Don’t touch that! Sit down and be quiet! Whether you heeded these commands as a child could help predict your future. A new study suggests that people who show less self-control as young children are more likely to have failing health, greater debt, and run-ins with the law later in life.

The idea that willpower is important for success is not new. In the late 1960s, Walter Mischel, a psychologist at Columbia University, tested whether 4-year-old children could resist nibbling Oreo cookies when left alone with a plate of them. He and colleagues found a huge range in willpower, and those children better at resisting the temptation went on to do better in school, scoring higher on the standardized tests. Their parents also judged them to be more attentive, competent, and intelligent. Intrigued, psychologist Terrie Moffitt of Duke University in Durham, North Carolina, and her colleagues sought real-life data to test whether individuals with more willpower and not just self-discipline when offered cookies, achieved greater success in life.

The international team tracked approximately 1000 New Zealand children, born in 1972 or 1973, from the age of 3 years until their early 30s, and another 500 British fraternal twins, born in 1994 or 1995, from the ages of 4 years to 12 years. They used a range of measures to assess the children’s self-control, including their impulsivity, persistence at a task, patience while waiting in line, and hyperactivity.

Compared with their more disciplined twins, children who had less self-control at age 5 were more likely to have begun smoking, performing badly in school, and acting out at age 12, the researchers report online today in the Proceedings of National Academy of Sciences. And these problems continued in later life. Controlling for socioeconomic status and IQ, the researchers determined that people who showed the lowest willpower as children went on to be more than twice as likely to have health problems in their 30s, including high blood pressure, weight problems, lung disease, and sexually transmitted diseases. By the age of 32, they also earned 20% less and were about three times more likely to be dependent on tobacco, alcohol, or harder drugs and to have been convicted of a crime.

Moffitt explains that people didn’t fall into two categories—disciplined or undisciplined—but existed on a spectrum. “It means all of us could benefit from improving our self-control,” she says.

Moshe Bar, a psychologist at Harvard Medical School in Boston who was not involved in the study, is impressed by the long-term data set but cautions that the study is observational and can’t establish that self-control breeds success. Still, parents of cookie nibblers shouldn’t despair, he says. He was intrigued to read that some of the children in the study improved their self-control. Bar and his 7- and 10-year-old children “play a game of ‘waiting’ with unwrapping a candy for no other reason than practicing a delay,” he says. “It works,” he says, but then, as he points out, he has a sample size of only two.

:: Read full here ::