Random Samples

Science  04 Apr 2008:
Vol. 320, Issue 5872, pp. 27

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    About 600 species of bacteria live in human mouths. Some cause cavities or periodontal disease, whereas others keep breath smelling fresh—but most have unspecified roles and are known only as DNA sequences. “All this myriad of data has been sort of dumped in GenBank,” says Floyd Dewhirst, a microbiologist at the Forsyth Institute in Boston, Massachusetts. “It's become a meaningless Tower of Babel.”

    But no longer. Dewhirst and a team of scientists funded by the National Institute of Dental and Craniofacial Research in Bethesda, Maryland, organized all the sequences in the Human Oral Microbiome Database, which went online 25 March (homd.org). Based on a new evolutionary tree, each species has been neatly assigned to a genus, numbered, and linked to bibliographic references. The entire database is searchable by key words and DNA sequences.


    Paul Lepp, a microbiologist at Minot State University in North Dakota, says the database will help generate an ecological perspective of disease, encouraging researchers to study how interactions among microbes foster health or disorder. The oral biome is the first of a series of microbiomes to go online; similar databases are in the works for skin, gut, and vaginal microbes.


    Why do gamblers on a losing streak keep playing till they go bust? Because their minds aren't flexible enough to change course, a recent study concludes.

    Psychiatric researchers at the University of Pisa in Italy compared how well 20 recovering gambling addicts and a healthy control group matched for IQ performed on the Wisconsin Card Sorting Test. WCST measures “executive function” such as planning and shifting cognitive strategies. Subjects learn to sort cards (see illustration) according to a particular rule, which the experimenter then covertly changes; participants are judged by how well they pick up on the shifts. In the Pisa study, the gamblers had much more difficulty adapting to new rules and, unlike the healthy people, actually got worse with practice. The results, the scientists reported last week in the journal Clinical Practice and Epidemiology in Mental Health, indicate “a sort of cognitive ‘rigidity’” that prevents people from looking for alternative solutions to problems and fosters the kind of “perseverating” thinking that gamblers indulge in.

    Yale University gambling researcher Marc Potenza says the study is interesting, but the results are uncertain given the small number of subjects and the fact that they suffer from other addictions and mental problems. Nonetheless, psychiatrist Jon Grant of the University of Minnesota, Minneapolis, says the study underscores that gambling, unlike, say, drinking, “is a cognitive task.” And it raises the question of whether such flaws in thinking are there all along but “don't show up until [people] get into gambling.”



    When the second Skylab crew lifted off in May 1973, the astronauts carried, unbeknownst to them, copies of this patch sent by their wives. It's a takeoff on the mission logo, adapted from the famous drawing by Leonardo da Vinci. Last week, one of the 320 original parody patches was sold for $388.38 at an auction of space artifacts in Dallas, Texas. One item still awaiting a buyer: a moon dust scoop used during the 1971 Apollo 14 flight and presented to backup commander Eugene Cernan, who became the last human to walk on the moon the following year. It was expected to fetch as much as $300,000, but no one picked it up, so it's now on sale for $161,325.



    Aeroponics—cultivating plants without soil or water—started to take off in 1983 when Rick Stoner of AgriHouse, a company in Berthoud, Colorado, patented a water-conserving, pesticide-free way to grow crops. NASA chipped in funding for application to potential future space colonies.

    The colonies are still beyond the horizon, but commercial production of air-grown veggies is becoming a reality. Optometrist Larry Forrest of Frederick, Colorado, has expanded his aeroponic greenhouse to about 150 square meters, which may make him the world's largest aeroponic farmer. His company, Grow Anywhere Air-Foods, grows tiny seedlings of mesclun and other greens for restaurants, misting their roots with a nitrogen- and calcium-rich spray every 20 minutes. Forrest's equipment involves several thousand nozzles, pipes, and other parts. But he says he is working on a simpler, cheaper 500-part system to sell to like-minded growers.

    “This is the first I've seen someone else trying to make a go of it,” says Edward Harwood, who patented an aeroponic system with a cloth conveyer belt but couldn't make it pay. As far as the U.S. growers know, the technique hasn't caught on anywhere else in the world. But Stoner sees a big potential: The technology “can be set up anywhere, including Iceland or Antarctica,” he says.