Asian Beetle's Impact Unclear
Researchers announced last week that a species of beetle native to East Asia has found its way to a forest in northern Massachusetts.
Entomologists are not certain whether this beetle is likely to harm its new environment, but so far it has shown no signs of ecological threat.
The three-millimeter-long ambrosia beetle, whose Latin name is Xyleborus seriatus, is usually not aggressive and attacks only sick or dead trees, said Robert Rabaglia, an entomologist at the Maryland Department of Agriculture.
What concerns some scientists is the fungus the beetle carries. "These beetles are called ambrosia beetles because they make galleries in dead trees, and they impregnate these galleries with fungus and feed on them; they don't feed on wood," said Richard Hoebeke, assistant curator of the insect collection at Cornell University. Some of the fungi are not pathogenic in their native countries, but they could kill the trees here.
"Most of these beetles come from East Asia, in the solid-wood packing materials" such as boxes, crates or raw cut wood used to stabilize shipments, Rabaglia said.
Rabaglia and Hoebeke discovered the newcomer as part of the federally funded Early Detection and Rapid Response of Invasive Species program. In the program's five years, scientists have found five new species of beetles.
Twenty species of ambrosia beetles have been introduced to the United States in the past 100 years, Rabaglia said, and "the rate of introduction has increased in the past 20 years."
"The concern should not be on this species, but on the fact that every year we seem to be getting more and more exotic species," some of which can threaten the ecology, he said.
-- Naseem Sowti
Famine, Schizophrenia Linked
Scientists have produced new evidence that people conceived during a famine are prone to schizophrenia.
A previous study found that children conceived during a food shortage in the Netherlands in 1944 and 1945 were twice as likely to develop the devastating mental illness, which is marked by hallucinations and delusions.
In the new study, David St. Clair of Shanghai Jiao Tong University in China and colleagues examined the records of people whose mothers lived through a famine in China from 1959 to 1961. The researchers focused on the Wuhu region of Anhui, one of the hardest-hit provinces, comparing schizophrenia rates among those born before, during and after the famine years by analyzing all psychiatric records from 1971 through 2001.
The risk of developing schizophrenia in later life increased from 0.84 percent in 1959 to 2.15 percent in 1960 and to 1.81 percent in 1961, the researchers reported in the Wednesday issue of the Journal of the American Medical Association. The risk was 2.3 times higher for those born in 1960 and 1.9 times higher for those born in 1961.
"Our findings are internally consistent and almost exactly replicate the Dutch findings," the researchers wrote. "Since the two populations are ethnically and culturally distinct, the processes involved may apply in all populations undergoing famine."
In an editorial accompanying the study, Richard Neugebauer of Columbia University in New York said researchers now need to determine whether a specific part of the diet is crucial.
"The most pressing question from a public health . . . perspective is whether the relevant nutritional restriction of interest constitutes a global nutritional deficiency or a specific micronutrient deficiency," Neugebauer wrote.
"If the former, the implications of this work are confined largely to developing countries where severe protein-calorie malnutrition is common. . . . If the latter, the implications extend to developed and developing countries alike."
-- Rob Stein
Study Delves Into Sleep Apnea
New research suggests that people who die in their sleep may have stopped breathing because of a long-term degeneration of certain cells in the brain.
Jack Feldman, a professor of neurobiology at the School of Medicine at the University of California at Los Angeles, said his team's findings could reveal the mechanism behind what is called "central" sleep apnea, usually diagnosed in people older than 65.
Sleep apnea refers to repetitive pauses in breathing during sleep.
In a paper published yesterday in the online edition of Nature Neuroscience, Feldman reported discovering a region of the brain stem in rats that consists of about 600 cells and that helps to control breathing rhythm. "We found that if we destroyed 80 percent of these cells, rats could not breathe normally," he said. He called this region preBotC.
"We speculate that what's happening is that humans may have a few thousand of these cells," Feldman said, and that these cells may be lost during a person's lifetime to the point that the brain cannot compensate for their loss and the person stops breathing as he sleeps. This could also be the case for patients who suffer from neurodegenerative diseases.
Leanne McKay, a postdoctoral fellow at UCLA and a member of Feldman's team, is studying the preBotC area in human brain tissue obtained from cadavers and plans to compare them to the brains of patients who died from a neurological disease such as Parkinson's or ALS -- Amyotrophic Lateral Sclerosis.
Ultimately, Feldman hopes his lab's research will lead to the development of treatments for those who suffer from central sleep apnea.
"We all take breathing for granted," he said.
-- Naseem Sowti