Eating red meat could make your body more vulnerable to a dangerous bacterial toxin, according to a new study. A sugar molecule, Neu5Gc, found in beef, lamb, pork, and unpasteurized milk can attach itself to the cells lining the human intestines and act as a magnet for toxins produced by certain strains of E. coli, often carried in the same meats. The result is bloody diarrhea and sometimes death. “This uncovered the first example of bacterium causing disease in humans by targeting a molecule which is incorporated into our bodies through what we eat,” [ABC Science] says researcher Travis Beddoe.
The study, published in Nature [subscription required], was conducted in petri dishes using mouse tissues and human cells. The scientists tested human gut and kidney cells steeped in these sugar molecules and discovered that the toxin was about seven times more likely to bind to these cells if the sugar was present. It is still “not clear how to extrapolate this precisely to the human body,” [Science News] says co-author Ajit Varki. That is, researchers don’t know exactly what it means for human health yet. (more…)
The toxic chemical melamine that has already contaminated Chinese milk and eggs may also have been widely used in animal feed, according to new reports from the Chinese state media. Chinese consumers were horrified when it was revealed in September that four babies had died and more than 50,000 were sickened due to tainted infant formula, and the outrage grew in October when eggs from four large companies were also found to be tainted. Since then, the widening scandal has caused companies across Asia to recall products made with Chinese milk or eggs, and the new reports suggest that there may be broader recalls to come.
Melamine can be used to make food products appear to have a higher protein content, and the new admission from the state-run media, which usually suppresses bad news, shows that the trick was commonly used. “The feed industry seems to have acquiesced to agree on using the chemical to reduce production costs while maintaining the protein count for quality inspections,” the state-run China Daily said in an editorial. “We cannot say for sure if the same chemical has made its way into other types of food,” the newspaper added [BBC News].
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A new analysis of Antarctic weather conditions has found that human-caused global warming is to blame for the changing climate at the south pole, according to a new study. In its landmark Fourth Assessment Report, the Intergovernmental Panel on Climate Change (IPCC) declared in 2007 that human influence on climate “has been detected in every continent except Antarctica” [Nature News]. Now, researchers have evidence that even that final frontier is feeling the heat from human activities.
In the study, published in Nature Geoscience [subscription required], researchers compared 100 years of Antarctic and Arctic climate records to the results of two sets of computerized climate models. Both sets factored in the effects of natural phenomena, such [as] volcanic eruptions and solar sunspot cycles, but only one set factored in the consequences of human activities that can affect climate, such as rising levels of the greenhouse gas carbon dioxide and fluctuations in the amount of ozone in the stratosphere. It was the models which included human factors that most closely matched the temperature profiles recorded at the poles. “For me, it can’t be more clear that human activity is responsible” [New Scientist], said study coauthor Alexey Karpechko.
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The Phoenician culture vanished from the Mediterranean following the fall of Carthage in 146 BC, when the Romans razed the city and (according to legend) salted the earth, but the Phoenician people didn’t fade away. A new genetic analysis shows that 1 in 17 men in the Mediterranean region have Phoenician DNA, and must be descended from those ancient seafarers.
The findings could fill a gap in the history of the Phoenician civilization, which originated two to three thousand years ago in the eastern Mediterranean—in what is now Lebanon and Syria—and included prominent traders, according to Chris Tyler-Smith, lead author…. “By the time of the Romans they more or less disappeared from history, and little has been known about them since” [National Geographic News].
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The oldest human to have his complete mitonchondrial (mtDNA) genome sequenced, a 5,000-year-old “Iceman” mummy known as Ötzi, does not appear to have any living relatives in Europe. The new genetic analysis reveals that Ötzi belonged to a previously unknown branch of human evolution. Said study coauthor Franco Rollo: “Apparently, this genetic group is no longer present…. We don’t know whether it is extinct or it has become extremely rare” [HealthDay News].
The researchers extracted DNA from Iceman’s rectum. They analyzed the genome of the cells’ energy-making structures, called mitochondria. “You only get mitochondrial DNA from your mother, and she gets it from her mother and so on, so it forms an unbroken link all the way back to the common maternal ancestor of all of us,” said researcher Martin Richards [LiveScience]. Earlier studies of fragments of Ötzi’s mtDNA had indicated that he was of the K1 lineage, which is further divided into three branches. But after comparing his complete mtDNA genome with that of 115 modern Europeans of K1 lineage, the researchers found three mutations that place Ötzi in a fourth, previously unknown, branch of K1.
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Researchers have gathered some clues to solve the mystery of what’s killing off hibernating bats throughout New England, but say they’re still far from knowing how to halt the strange die-off. In a new study, researchers identified the characteristic white fungus that has been found on the noses of dead and dying bats, and say it’s a new species of mold that thrives at low temperatures like those found in caves in the winter. But debate still continues over whether the fungus is the cause of death, or simply a secondary infection that takes advantage of bats with already weakened immune systems.
Bats covered with the fungus, a sickness now called white-nose syndrome, were first spotted in Howes Cave near Albany, N.Y., during the winter of 2006. At that time, field biologists reported caves that were typically covered with hibernating bats had loads of vacancies…. In one case, a cave floor was littered with dead bats [LiveScience]. Since then, the epidemic has spread throughout Connecticut, Massachusetts, Maine, and Vermont, with 80 to 100 percent of bats dying in some caves.
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After several weeks of remote-control repair work, the Hubble Space Telescope is back in action, and is once again taking breathtaking images of distant galaxies. Today, NASA released an image which it called a “perfect 10″ because the paired galaxies resemble the number 10. The picture was released this morning by NASA to demonstrate that the observatory’s workhorse Wide Field Planetary Camera 2 is on the job again [Baltimore Sun], and a happy NASA press release added that the camera scored a perfect 10 for both its performance and the beautiful results.
The image shows a pair of galaxies, known as Arp 147, which are about 400 million light years away from Earth. The two galaxies are thought to have collided, and the image shows that aftermath. The blue ring was formed after the galaxy on the left passed through the galaxy on the right. Just as a pebble thrown into a pond creates an outwardly moving circular wave, or ripples, an outwardly propagating ring of higher density was generated at the point of impact of the two galaxies, astronomers explained. As this excess density collided with outer material that was moving inwards due to the gravitational pull of the two galaxies, shocks and dense gas were produced, stimulating star formation [SPACE.com].
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Pity the poor frogs: they’re one of the most endangered group of vertebrates on the planet, and new research shows that two of the factors in their plight are common, everyday farm chemicals. The study shows that atrazine, a weedkiller that’s widely used in agricultural areas, not only boosts the levels of parasitic flatworms in frog ponds, it also decreases tadpoles’ ability to fight off infections. If that wasn’t bad enough, previous research has found that runoff from phosphate fertilizers also boosts parasite levels. Taken together, researchers say, the weedkiller and the fertilizers are hitting frogs with a double whammy.
Amphibian populations around the world have been declining in recent decades, with many species on the brink of extinction. Infection with any of several species of tiny flatworms, known as trematodes, can trigger debilitating limb deformities in frogs. Severe infections can kill the amphibians. The question was why high rates of those deformities — and, presumably, trematode infections — began showing up across the nation in the mid-1990s [Science News]. The new findings suggest that the growing prevalence of the weedkiller atrazine in corn-growing regions since that time may be partly to blame for the woeful state of American amphibians.
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On October 6, NASA’s Messenger space probe swooped down to within 125 miles of the surface of Mercury, and the just-released images from that flyby are shaking up astronomers’ ideas about the planet’s geologic history. The remarkable pictures reveal a vast patch of lava, indicating that the planet was shaped by a long age of volcanic eruptions. Astronomers used to dismiss Mercury, the planet closest to the sun, as mere “dead rock,” little more than a target for cosmic collisions that shaped it, said MIT planetary scientist Maria Zuber. “Now, it’s looking a lot more interesting,” said Zuber [AP].
Messenger’s cameras spotted a crater of about 60 miles in diameter that was not as deep as other nearby craters, and determined that it had been filled in with a huge amount of solidified lava. To get an idea of how much, Zuber explains, you could imagine the entire Baltimore-Washington region covered with a layer of solidified lava about 12 times the height of the Washington monument. “So it’s a great, great deal of vulcanism,” she says. “That’s an awful lot of volcanic material in one place for such a little planet” [NPR News]. Researchers think the eruption happened between 3.8 and 4 billion years ago.
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Opal has been detected on Mars by NASA‘s Mars Reconnaissance Orbiter (MRO), an encouraging sign that water may have existed on the planet as recently as two billion years ago. The opal, a hydrated silicate, is the youngest hydrated mineral yet to be found on the 4.5 billion-year-old planet and significantly widens the window of time that Mars is believed to have supported water. “This is an exciting discovery because it extends the time range for liquid water on Mars, and the places where it might have supported life,” [SPACE.com] said team leader Scott Murchie.
Hydrated minerals require water to form and two types have been found on the Red Planet before. The oldest hydrated materials are clay-like phyllosilicates, which formed more than 3.5 billion years ago when volcanic rocks bathed for long periods of time in water. Later, hydrated sulfates formed when salty and occasionally acidic water evaporated [Discovery News]. The newly found hydrated silicates, described in Geology [subscription required], appeared even later, as acidic liquid water slowly altered materials created from volcanic activity and meteorite impacts. Team member Ralph Milliken explains that the water “was there long enough to alter some of the rocks…. It wasn’t an overnight process” [SPACE.com].
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Two groups of geologists have found evidence that the Indian Ocean tsunami that devastated coastal towns in Southeast Asia in 2004 wasn’t the first massive wave to pummel those shores, but the last tsunami of equivalent size occurred about 600 to 700 years ago. That long gap might explain how enough geological stress built up to power the huge undersea earthquake that launched the killer waves four years ago, researchers said [AP].
One group of researchers took sediment samples on a barrier island off the west coast of Thailand, while the other group dug into the soil in a northern region of Sumatra. The surge of a tsunami brings with it a great deal of sediment that rushes inland; the bigger the tsunami, the deeper and further inland the layer of sediment it leaves behind. In locations where those deposits aren’t disturbed by wind or running water, they can be used as a historical record of tsunami after more layers are added later [BBC News].
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Researchers have used a CT scanner to peer inside the hollow, fossilized skulls of a group of meat-eating dinosaurs that dominated the Jurassic Period, and found that the Tyrannosaurus rex had another advantage besides its size, speed, and pointy teeth–it also had an excellent sense of smell. Study coauthor Darla Zelenitsky says the scans show the impressions left on the skull by different brain regions, and says the T. rex had the biggest olfactory bulb, which regulates the sense of smell.
Zelenitsky says the findings suggest that the T. rex relied on smell extensively. “It’s probably fairly significant, because the sense of smell was likely used for foraging or searching for food,” Zelenitsky said. “And as well, it could have been used for patrolling relatively large home ranges. So, in that respect, it would have been a significant part of the biology and daily activities of the animal” [Calgary Herald].
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Yesterday, 7.2 metric tons of elephant tusks were auctioned off to ivory buyers from China and Japan, bringing in a total of $1.1 million for the seller, the Namibian government. The controversial sale was the first of four auctions that will be carried out over the next few weeks in a program approved by CITES, the international watchdog group that monitors trade in endangered species. The sales are intended to let southern African countries dispose of their ivory stockpiles, and CITES hopes that releasing legal ivory onto the market will decrease the demand for poached ivory.
However, some conservation groups worry that the sale will have the opposite effect, and may allow black market ivory dealers to label their goods as products from the legal auction. Says a spokesman for the International Fund for Animal Welfare, Michael Wamithi: “By permitting legal trade in ivory, we are only encouraging the laundering of stocks by poachers, thereby increasing illegal hunting activities…. The situation is very clear: More ivory in the market place equals many more dead elephants’’ [The New York Times blog].
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The cold, dark winter is fast descending on Mars, and now it’s time for NASA’s Mars Phoenix Lander, which has conducted five months of (literally) groundbreaking research near the Martian north pole, to begin slowly shutting down. Phoenix’s Earth-bound managers announced yesterday that the lander’s solar panels are generating less power from the decreasing sunlight, while at the same time the craft’s heaters require more energy to keep the lander operational as temperatures drop.
NASA‘s engineers were prepared for this inevitability, and say they’ll now begin to shut down some of its systems to save power for the lander’s main camera and meteorological instruments. “If we did nothing, it wouldn’t be long before the power needed to operate the spacecraft would exceed the amount of power it generates on a daily basis,” said Phoenix Project Manager Barry Goldstein…. “By turning off some heaters and instruments, we can extend the life of the lander by several weeks and still conduct some science” [The Tech Herald].
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Tennis referees are far more likely to make wrong “out” calls than wrong “in” calls, according to a new study. A quirk of our visual perception system, which helps us anticipate the motion of an object, seems to bias our perception of where a speeding tennis ball stops moving. “This is not a problem with referees,” says study co-author David Whitney…. “It’s a consequence of human visual processing … a visual illusion caused by a mechanism that allows the system to localize a moving object” [Scientific American].
The idea to study this visual illusion in a real-world context came to Whitney during a Wimbledon match as he watched a player challenge and overturn a referee’s call. For the study, published in Current Biology [subscription required], the researchers used Hawk-Eye technology, a system of high-speed cameras that is often used for contested calls in tennis matches. Three scientists independently reviewed video and instant replay of 4,457 randomly selected points from the 2007 Wimbledon championships. Of the 83 calls that the video and instant replay showed were wrong, 70 were “out” calls [Scientific American]. Without the visual bias, there should have been the same number of wrong “out” calls as “in” calls.
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