Monday, February 4, 2008

Study Questions Plague's Power

The Black Death ravaged Europe in the middle of the 14th century, killing as much as half of the population in some areas. Many experts have thought the plague was so deadly that it killed indiscriminately, taking the strong as often as the weak, but new research is challenging that notion.

Sharon N. DeWitte of the University at Albany and James W. Wood of Pennsylvania State University analyzed 490 skeletons that had been excavated from the East Smithfield cemetery in London, which was established exclusively to bury victims of the plague.

The researchers determined the health of the victims by examining defects in their bones, features that can indicate other health or nutritional problems. The researchers compared the skeletons with those of 291 similar individuals buried at a Danish cemetery shortly before the plague began.

Although healthy people did die from the plague, which is caused by the bacterium Yersinia pestis, the researchers found that the epidemic was more likely to kill people made vulnerable because they were already ill or malnourished, according to a report published last week in the Proceedings of the National Academy of Sciences. Although this finding seems unsurprising, some global epidemics, such as the 1918 flu, have taken an unusually high toll among young, healthy people.

"Black Death did kill people who were otherwise healthy," DeWitte said. "But we found quantitative evidence against the assumption that the Black Death killed indiscriminately. This runs contrary to what a lot of people thought."

-- Rob Stein

How Plant Digests Bugs Is Detailed

Pity the fly on the pitcher plant. Having landed on the tropical plant's vaselike structure, which looks no more dangerous than a partially unfurled leaf, the insect tumbles down the six-inch chute and lands in a pool of liquid.

Not just any liquid, it turns out, but a brew of digestive juices that gradually dissolves the hapless bug.

Scientists have wondered for at least a century what chemicals are in the pitcher plant's juice -- and how it turns insects, with their tough exoskeletons, into mushy dietary supplements. Now a team from Japan has done the first thorough analysis of that fluid, answering some old questions and raising a few new ones.

The carnivorous plants, which live mostly in the Asian tropics but have also become popular houseplants in the West, rely on occasional insect snacks to stay nourished, since they mostly grow in nutrient-depleted soil. Charles Darwin himself was fascinated by the plants, and wrote a book about them in 1875.

"The fact that a plant should secrete, when properly excited, a fluid containing an acid and ferment, closely analogous to the digestive fluid of an animal, was certainly a remarkable discovery," he wrote.

Similarly entranced, Naoya Hatano, now of Kagawa University, and Tatsuro Hamada of Ishikawa Prefectural University used tandem mass spectrometry and other high-tech methods to identify the enzymes in digestive fluid from the pitcher plant Nepenthes alata.

Of the seven enzymes they found, one breaks down chitin, the main ingredient of insect exoskeletons; two break down the proteins in insect muscles; two can kill bacteria, presumably helping to keep the partially digested insects from putrefying; and one appears to be involved in helping the young pitcher bud mature and open its insectivorous maw.

One other ingredient was found but remains unidentified, the team reported in the Jan. 28 issue of the Journal of Proteome Research.

-- Rick Weiss

Beatles Song Has Ticket to Ride

NASA will beam a song directly into deep space for the first time ever today -- and quite appropriately it will be the Beatles' "Across the Universe."

The transmission will take place over the space agency's Deep Space Network and will commemorate the 40th anniversary of the day the Beatles recorded the song, as well as the 50th anniversary of NASA's founding.

The song will travel across the universe at a speed of 186,000 miles per second and will be aimed at the North Star, Polaris, which is 431 light-years from Earth. Sir Paul McCartney said he is excited that the tune, written primarily by fellow Beatle John Lennon, is being beamed into the cosmos.

"Amazing! Well done, NASA!" McCartney said in a message to the space agency. "Send my love to the aliens. All the best, Paul."

Lennon's widow, Yoko Ono, said, "I see that this is the beginning of the new age in which we will communicate with billions of planets across the universe."

NASA's Jet Propulsion Laboratory in Pasadena, Calif., operates the Deep Space Network, which consists of deep-space communications facilities placed about 120 degrees apart around the world: at Goldstone, in California's Mojave Desert; near Madrid, Spain; and near Canberra, Australia. The system aids interplanetary spacecraft missions and radio and radar astronomy observations.

-- Marc Kaufman

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