Blogs / 80beats

Researchers have determined the mechanism by which the world’s simplest vision system works. A team of biologists spent a decade studying the larvae of the marine rag-worm Platynereis, a tiny creature with just two cells that respond to light and direct the worm to swim towards it. The rag-worm and other zooplankton like krill drift in the ocean’s water columns, swimming up from the depths towards the light in order to graze on marine plants called phytoplankton near the surface. This movement, called phototaxis, is the biggest biomass displacement in the world [AFP].

The rag-worm has two cells that work together as “proto-eyes”: one pigment cell and one light-sensitive cell. First, the pigment cell absorbs light and casts a shadow over the photoreceptor cell. The shape of the shadow varies according to the position of the light source. The photoreceptor cell then converts this light signal into electricity, sending it in a signal along a nerve that connects to a band of cells endowed with thin hairs, called cilia, that beat to displace water [AFP]. So although the worm sees no images, it can sense the difference between light and dark and swim in the right direction.

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The genome of the woolly mammoth is halfway sequenced and science-fiction fanatics are once again talking about resurrecting extinct species–except this time, the scientists are talking too. Researchers at Pennsylvania State University extracted DNA from the hair of two woolly mammoths found in the permafrost of Siberia; one lived about 20,000 years ago, the other about 60,000 years ago. Reporting in Nature [subscription required], the researchers say they have already sequenced more than three billion base pairs of the mammoth genome, and they say there should be no technical obstacles to sequencing the complete genome. “It’s a technical breakthrough,” says ancient-DNA expert Hendrik N. Poinar [Scientific American].

Access to clumps of preserved mammoth hair was essential to the researchers’ success. The tough keratin that makes up the hair encased the mammoth’s DNA and separated it from any alien fragments, keeping these samples more pure [New Scientist]. Horns and feathers are also made of keratin, broadening the prospects of sequencing other extinct species from museum specimens.

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Madeleine Pickens, wife of the eccentric billionaire tycoon T. Boone Pickens, wants to ride to the rescue of a beleaguered national icon. The wild horses that have been an emblem of the wide-open American West for centuries more recently became a major headache for the federal government, which routinely removes some of the horses from 1o Western states to prevent overpopulation and protect grazing land. But as the Bureau of Land Management’s (BLM) holding facilities grew crowded, federal officials gingerly announced that they were considering a euthanasia program to cull the herds at their facilities and contain costs.

Pickens, a racehorse breeder and lifelong animal lover, said she was horrified when she learned about the problem. “There’s got to be a way to bypass [the BLM] — why does it have to be Washington to solve the problem?” said Pickens, who, along with her husband, airlifted 800 cats and dogs stranded by Hurricane Katrina in New Orleans and brought them to California for adoption [Washington Post]. Pickens approached BLM officials and suggested an alternative: She would buy 1 million acres of rangeland somewhere in the West, and convert it into a permanent retirement home for the roughly 30,000 homeless and unwanted horses.

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The germ-fighting power of bleach lies in its ability to unravel cellular proteins, according to a new study. Researchers at the University of Michigan report that the active ingredient in bleach, hypochlorous acid, irreparably alters the three-dimensional structure of proteins in living cells—to fatal effect. They also found that some bacteria possess a special protein that can somewhat counter the ravages of hypochlorous acid. The findings clear up a hitherto murky understanding of how the common household cleaner does its job. “Everyone knew that bleached worked, and that was enough,” says [researcher Ursula Jacob]. “Few really cared how it worked” [Nature News].

In fact, Jacob’s team didn’t set out to answer that question either. They were studying a bacterial protein known as heat shock protein 33 (Hsp33) that helps other proteins maintain their proper shapes. Hsp33 is activated in times of stress, such as when the bacteria is exposed to high temperatures. “At high temperatures, proteins begin to lose their three-dimensional molecular structure and start to clump together and form large, insoluble aggregates, just like when you boil an egg,” said study lead author Jeannette Winter… Like a boiled egg, those proteins can never revert to their previous state, and the stressed cells eventually die [LiveScience.com].

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It’s not just we humans who value consensus: A new study has shown that stickleback fish make better decisions when acting as a group than they do as individuals. Researchers set up a clever experiment in which the fish had to choose which leader to follow in the quest for food, giving them an option between a “good” choice and a “bad” choice. Based on earlier experiments, the study’s researchers had a pretty good idea about … stickleback preferences. Fat, evenly colored fish are regarded as healthy and strong, while scrawny fish mottled with black spots may be considered diseased. Coauthor Ashley Ward … says of these sticklebacks, “Fish like large leaders, well-fed leaders and unparasitized leaders” [Science News].

Researchers made a stickleback replica that looked healthy and fat as well as one that appeared bony and mottled, and put both into the fish tank. When shown the fish replicas, the other sticklebacks in the tank would approach and follow one of the two replicas, which were moved around by remote control. Following a certain fish would be their version of casting a ballot…. When just one fish chose its leader, the fish would make the right choice, picking the healthiest leader about 55 percent of the time. That number went up to 80 percent with the eight-fish electorate [LiveScience].

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The issue of the First Dog came to national attention with Barack Obama’s first press conference as President-elect, when he announced that the lucky puppy would have to be hypoallergenic due to older daughter Malia’s allergies. Since then, nominations for First Dog have come from all sides, even from foreign countries: Peru has offered to send a Peruvian Hairless Dog, prized by Incan kings, to the Obamas. But all the buzz has prompted a reality check from the American Academy of Allergy Asthma & Immunology (AAAAI), which released a statement today reminding people that there is no such thing as a truly hypoallergenic dog.

Avoiding dog allergies completely may not be an option. It’s a misconception that dog allergies are caused by the dog’s hair. Allergies are caused by protein from the animal’s dander, which can be found in dead skin cells, saliva and urine. These microscopic proteins travel through the air and are inhaled, triggering an allergic reaction in, well, quite a few people [Los Angeles Times]. Studies suggest there are about 10 million Americans who suffer from dog allergies, but sensitivity varies and some people may do fine with certain breeds that are more allergy-friendly. These breeds may produce less dander or are groomed more often to keep dander at bay. Breeds often considered allergy-friendly include poodles, Kerry blue terriers, schnauzers, bichons and lhasa apsos.

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Poor Lonesome George: Although he may have found a mate, researchers say he is still being denied the joys of fatherhood. George is thought to be the last representative of a tortoise subspecies from the Galapagos Island of Pinta, and researchers rejoiced this summer when he appeared to father a batch of eggs. But earlier this week a spokesperson for the Galapagos National Park announced that 80 percent of the eggs do not appear to be viable.

The excitement began this summer when two female tortoises exhibited surprising behavior. The females, who have shared George’s enclosure at the Charles Darwin Research Station on the central island of Santa Cruz for almost 20 years, are of a different but closely related species. After decades of reproductive reticence, they stunned scientists during the summer by building nests and filling them with eggs for the first time [Nature News]. Researchers quickly removed the 16 eggs from the nests and installed them in an artificial incubator, although three of those eggs were thought to have already deteriorated.

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The U.S. Supreme Court has sided with the Navy over the Pacific Ocean’s whales, declaring that the Navy can continue its military exercises using high-powered sonar, despite environmentalists’ arguments that the sonar can harm whales’ ears or cause the panicked animals to beach themselves. The court ruled, in a 5-4 decision, that national security needs override these concerns. Chief Justice John Roberts wrote the majority opinion, stating: “Of course, military interests do not always trump other considerations, and we have not held that they do. In this case, however, the proper determination of where the public interest lies does not strike us as a close question” [ABC News].

The lawsuit centered on 14 sonar exercises that the Navy wanted to conduct off the coast of Southern California to train seamen in detecting enemy submarines. In his opinion, Roberts stressed the military threat posed by modern subs. “Modern diesel-electric submarines . . . can operate almost silently, making them extremely difficult to detect and track.” America’s potential adversaries have at least 300 of these subs, he said. “The president — the commander in chief — has determined that the training with active sonar is ‘essential to the national security’” [Los Angeles Times].

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How do you get a snot sample from a shy behemoth of the deep? That question stumped researchers studying whale health, who wanted to give the animals check-ups without corralling and traumatizing them. Now, researchers have come up with an ingenious answer, flying a remote-control helicopter through the jets ejected by the whales’ blowholes. The helicopter has petri dishes strapped to it, which collect any bacteria, fungi, and viruses that were in the whales’ lungs.

The collected samples could make a big contribution to scientists’ understanding of infectious diseases in whale populations. Researcher Karina Acevedo-Whitehouse explains: “We don’t know much about them because they are so big and they are in the water all the time, and that makes it really difficult to obtain biological samples that are relevant to determining health in these populations; unless they’ve already stranded or unless they are in captivity, which are hardly representative of a normal population” [BBC News].

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You may not want to think about what goes into your fast food, but a new study may at least put your overactive imagination to rest: It’s mostly corn. The researchers analyzed hamburgers, chicken sandwiches, and fries from McDonald’s, Burger King, and Wendy’s and determined that nearly all of them could be traced to the corn industry– in the form of corn feed or corn-based oil. “If you put any money into fast food, it all goes back to corn, everything. The first step to making hamburgers is making an ear of corn,” said Hope Jahren, lead author of the study [Des Moines Register].

The researchers traveled to Los Angeles, San Francisco, Denver, Detroit, Boston and Baltimore, purchasing feasts of fast food at multiple restaurants in each city. Samples of beef, chicken, and fries were then ground up and analyzed for levels of isotopes. Specifically, they were looking for carbon-13, which is a unique signature of corn, and nitrogen-15, which is found in fertilizers and animal excrement. Based on the high levels of carbon and nitrogen isotopes found in the meat products, the authors claim that the cattle and poultry were predominantly fed corn, which makes them as fat as possible in as short a time as possible, and were raised in extreme confinement [Forbes.com], keeping the animals in close contact with their own excrement. The high nitrogen-15 content also suggests the corn fields were heavily fertilized with nitrogen-based fertilizers.

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The roots of mammalian hair go far back into evolutionary history, according to a new study. Hair, which provides insulation and protection, is seen as one of the main evolutionary innovations that led to the rise of mammals. But the origins of hair date back to an unknown reptile ancestor that lived more than 300 million years ago, in the Paleozoic era, the new study says [National Geographic News].

Previously, biologists had considered the possibility that hair evolved from scales or feathers, but the paucity of fossils showing the evolution from reptiles to mammals has made the question a hard one to examine. So in this new study, published in the Proceedings of the National Academy of Sciences [subscription required], researchers ignored the fossil record and looked instead to the genetic record of living animals: namely, a chicken and an anole lizard.

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Using boat, tags, nets, and submarines, marine biologists from 82 nations have been canvassing the oceans for the first Census of Marine Life, an ambitious effort to get a rough tally of all the creatures in the world’s oceans. The 10-year project is expected to conclude in 2010, and researchers say the broad survey will help them observe changes to marine ecosystems. Says co-senior scientist Ron O’Dor: “We are moving into this period of global warming, which is resulting in the acidification of the oceans, melting of the polar ice cap. We can use the first census as a benchmark to see what happens in the oceans over the next decade or more” [BBC News].

Although the project still has two years to go, researchers have already made a host of startling discoveries, many of which will be discussed this week at the World Conference on Marine Biodiversity in Valencia, Spain. In one study, researchers conducted a genetic analysis of deep sea octopuses from around the world, and determined that most descended from a common ancestor species that still lives near Antarctica. Researchers believe that octopuses started migrating to new ocean basins more than 30 million years ago when, as Antarctica cooled and a large icesheet grew, nature created a “thermohaline expressway,” a northbound flow of tasty frigid water with high salt and oxygen content. Isolated in new habitat conditions, many different species evolved; some octopuses, for example, losing their defensive ink sacs — pointless at perpetually dark depths [LiveScience].

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The European Commission has proposed a ban on medical research performed on our species’ closest relatives, the great apes. The pan-European initiative would extend a ban already in force in Austria, Great Britain, the Netherlands, and Sweden across the entire 27-member bloc. The ban, however, would not greatly affect current research, because no testing has been carried out on great apes in the EU for the past six years [The Scientist]. Nevertheless, the proposal [pdf] has received mixed reviews from both the scientific community, who fear excessive red tape, and animal rights groups, who say the ban does not go far enough.

If approved, the ban would prohibit researchers from using great apes, including chimpanzees, bonobos, gorillas, and orangutans, to test scientific “procedures,” although behavioral studies will still be allowed. There will also be exceptions for research that could save a great ape species threatened with extinction and in the case of a serious pandemic that affects humans. The proposal also affects research on other animals, stressing the “3Rs” of reducing the number of animals used, refining techniques to lessen pain and discomfort, and replacing animal studies with alternatives [ScienceNOW Daily News]. Some 12 million vertebrate animals are used each year in experiments throughout the 27-nation bloc — half for drug development and testing, a third for biology studies and the rest for cosmetics tests, toxicology and disease diagnosis [Reuters].

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Warmer winters in Norway seem to be causing a decline in lemming populations, according to a new study, and researchers say the decline of the rodent is having a cascading effect. Lemming predators, like foxes and owls, have been forced to hunt different prey in what researchers call a clear-cut example of how global warming can have a disruptive impact on entire ecosystems.

Lemming populations throughout Scandinavia tend to explode naturally every three to five years, causing huge numbers to go in search of food. Occasionally this leads the rodents to jump into water and swim to new pastures new—the origin of the myth that lemmings commit mass suicide. When lemmings boom, they’re hard to miss. Norwegians have had to use snowplows to clear the squashed rodents off the roads [National Geographic News]. But the study of lemming populations during the last four decades found no population explosions since 1994.

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A newly discovered tree fungus could be on its way to the gas station. The fungus, Gliocladium roseum, is able to turn plant matter into gaseous hydrocarbons that are almost chemically identical to diesel fuel. “This is the only organism that has ever been shown to produce such an important combination of fuel substances,” said researcher Gary Strobel from Montana State University. “The fungus can even make these diesel compounds from cellulose, which would make it a better source of biofuel than anything we use at the moment” [LiveScience].

The fungus grows inside trees in the rainforests of Patagonia, in the southern part of Argentina and Chile. After discovering the new fungus wedged between cells in a stem from an Ulmo tree (Eucryphia cordifolia), Strobel and colleagues cultured the organism, collected the gaseous compounds it produced, and ran the compounds through a mass spectrometer to identify them. When he saw the printout, Strobel says, “every hair on my body stood up.” The list included octane, 1-octene, heptane, 2-methyl, and hexadecane–all common components of diesel fuels [ScienceNOW]. The gaseous compound, dubbed “myco-diesel,” is thought to be used by G. roseum to poison other fungi.

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