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Compendium April 2005 (Vol 27, No 4)

News Bites (April 2005)

    Small Chip Performs Big Tests ... Fast

    Researchers at the University of Buffalo have developed a tiny silicon chip that mea­sures changes in electrical impedance due to changes in cell volume. The technology is based on cell-volume cytometry: the connection between cell volume, environment, and function. Normal activity, such as metabolism and division, affects cell volume. Cell volume is also affected by abnormal activity such as exposure to toxic agents. By mea­suring changes in cell dimension so small they've never been observed in living cells before, antibiotic sensitivity, chemotherapeutic effectiveness, and toxin exposure can be measured in minutes. The chip is simple to use, inexpensive, and portable and can be used on any biologic component encased in a membrane. (Hua, Sachs, et al: Analytical Chem 77[4], 2005)

    "Like Parent, Like Offspring" No More

    Purdue scientists have found plants that possess a corrected version of a defective gene handed down by both parents. The implication is that some organisms may carry a backup copy of genetic material that somehow bypasses the usual mechanisms of heredity. If confirmed, this is the first time the laws of inheritance, discovered by Gregor Mendel and demonstrated in his pea plants, would be successfully challenged. The most amazing thing about this discovery is that the corrected gene does not appear in the plant's DNA. Researchers suspect that RNA may be involved, but the mechanism is unclear because RNA usually accumulates many more errors than DNA in the copying process. The finding could also challenge the leading theory of why sex is necessary: to discard bad mutations. The backup genome may be used in self-fertilizing plants and possibly bdelloid rotifers (known not to have sex for millions of years) to prevent the hazards of inbreeding. (Wade N: Startling scientists, plant fixes its flawed gene. The New York Times. Available at www.nytimes.com; accessed March 2005)

    Part of Columbia Lived On

    Hundreds of tiny worms on board for experimental reasons survived the breakup of the Columbia space shuttle during reentry into the Earth's atmosphere in 2003. Recovered canisters containing the worms were opened almost 3 months after the crash. The worms, known as Caenorhabditis elegans, exited the craft at a speed of 660 to 1,050 km/hr, descending from 42 to 32 km above earth. Columbia seems to have survived long enough to protect the worms from some of the shear forces, frictional heat, shock waves, and freezing atmospheric temperatures. Researchers think the canisters acted as mini spacesuits. Although the survival potential of C. elegans is much higher than a human's because of its ability to withstand greater gravity, a day of anoxia, and lack of food for up to 6 months, the worms' survival may make the case for using spacesuits, an encapsulating escape system, or other technology to prevent thermal degradation in astronauts. (Szewczyk NJ, McLamb W: Surviving atmospheric spacecraft breakup. Wilderness Environ Med 16:27-32, 2005)

    NEXT: The Editor's Desk: "Reconciling Science and Faith"