Archive for October, 2008

Red Meat Acts as Trojan Horse for Toxic Attack by E. Coli

By Nina Bai | October 31, 2008 7:04 pm

red meatEating 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. Read More

CATEGORIZED UNDER: Health & Medicine

China's Tainted Food Scandal Grows Worse: Animal Feed May Be Contaminated

By Eliza Strickland | October 31, 2008 2:17 pm

China contaminated milk melamineThe 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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CATEGORIZED UNDER: Health & Medicine

New Study: "Humans Are Responsible" for Warming Even Antarctica

By Eliza Strickland | October 31, 2008 11:01 am

icebergA 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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CATEGORIZED UNDER: Environment

Ancient Phoenicians Left Their DNA in the Mediterranean Gene Pool

By Eliza Strickland | October 31, 2008 8:36 am

Phoenician ruinsThe 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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CATEGORIZED UNDER: Human Origins
MORE ABOUT: archaeology, genetics

Iceman Mummy Lost Darwin's Game: He Seems to Have No Modern Kin

By Nina Bai | October 30, 2008 5:57 pm

alpsThe 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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CATEGORIZED UNDER: Human Origins

Bats Are Dying From White Nose Mold, But Researchers Don’t Know Why

By Eliza Strickland | October 30, 2008 4:30 pm

bat white nose fungusResearchers 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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CATEGORIZED UNDER: Living World

A Restored Hubble Telescope Resumes Gazing at the Universe's Wonders

By Eliza Strickland | October 30, 2008 1:51 pm

Hubble Arp 147 paired galaxiesAfter 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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CATEGORIZED UNDER: Space, Technology

Frogs Get a One-Two Punch From Farm Chemicals

By Eliza Strickland | October 30, 2008 10:20 am

leopard frogPity 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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CATEGORIZED UNDER: Living World

Mercury Close-Ups Reveal the Planet's Ancient Volcanic Eruptions

By Eliza Strickland | October 30, 2008 8:32 am

Mercury cratersOn 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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CATEGORIZED UNDER: Space

Martian Stones Suggest a More Recent Watery Past

By Nina Bai | October 29, 2008 6:04 pm

opalOpal 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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CATEGORIZED UNDER: Space
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