Research News

Wound-healing power in electricity

Since older people and individuals with diabetes often experience slow wound healing, understanding electricity's role in the process may reveal new treatment options. In collaborative work, cell biology professor Richard Nuccitelli and Rivkah Isseroff, professor of dermatology in the School of Medicine, studied how electrical fields direct the migration of "rebuilder" cells in human and animal wounds.

In one laboratory study of human skin cells, the researchers showed that not only is the rate at which these "rebuilder" cells congregate determined by electrical charge, but so is the particular "highway " on which the cells travel. This work is published in the Journal of Investigative Dermatology.

In a separate study published recently in the Journal of Cell Science, they show that the human "rebuilder cells," or keratinocytes, migrate fastest under the same electric field strengths that occur naturally in other mammal wounds. This finding lends credence to the theory that electrical current is an important stimulus of wound healing in all mammals.

References: Sheridan DM, Isseroff RR, and Nuccitelli R. 1996. Journal of Investigative Dermatology 106(4):642-646. Nishimura KY, Isseroff RR, Nuccitelli R. 1996. Journal of Cell Science 109:199-107.

Anemone gladiators

"Morphologically, they're gelatinous bags of snot," sums up Professor Rick Grosberg of Evolution and Ecology and the Center for Population Biology.

So, he and his Australian collaborator, David Ayre, were surprised to find a complex array of aggressive behaviors exhibited in 148 anemone bouts they set up in the lab. Last year, the researchers reported that some anemones seemed to "remember" an opponent's style and respond faster in a second match.

In a paper published last summer in the journal Animal Behaviour, Ayre and Grosberg report that genetically identical anemones can grow into two types--warriors, with big weapons, small bodies and small gonads, or reproductives, with large bodies and gonads and few attack tentacles. In the wild, anemones clone themselves and live in genetically segregated neighborhoods; there, anemones living on borders become warriors. In the lab, faced with an enemy (from a different clone), a reproductive anemone begins to transform into a warrior.

Also, some anemone clones field much better fighters. A sea anemone fight begins when the feeding tentacles touch. Tempers flare, and an anemone unsheaths its collar of stinging tentacles. The attacking anemone will lunge to strike, landing a thin layer of painful cells that leave scars like cigarette burns. Defending anemones will bravely tough it out and retaliate or timidly attempt to crawl out of reach.

Reference: Ayre DJ and Grosberg RK. 1996. Animal Behaviour 51(6):1233-1245.

Polar fish proteins may extend shelf life of blood

The results of the study, conducted by Fern Tablin, associate professor in the veterinary school, and Professor John Crowe in Molecular and Cellular Biology, appeared in a recent issue of the Journal of Cellular Physiology.

A patent is pending on this new technique for treating platelets and the technology has been licensed for commercial use to A/F Protein of Boston.

Essential for blood to clot, platelets are important in controlling bleeding and also are widely used in transfusions for patients with leukemia and other forms of cancer.

"If it works, this technique could both significantly increase the supply of platelets as well as decrease the number of deaths due to bacterial infections from platelet transfusions," says physician Morris Blajchman, an authority in hematology and transfusion medicine at McMaster University in Hamilton, Ontario.

According to Blajchman, who is also medical officer for the Canadian Red Cross, bacterial contamination of platelets is the most common problem associated with transfusions, significantly affecting approximately one in every 2,000 transfusion recipients.

Reference: Tablin F, Oliver AE, Walker NJ, Crowe LM, et al. 1996. Journal of Cellular Physiology 168(2):305-313.

World Wide Web sprouts trees of life

Researchers at UC Davis and elsewhere have taken advantage of quantum leaps in computing power, Internet access, molecular data, and scientific interest to build elaborate databases reconstructing evolutionary relationships, or phylogenies, and to make them freely available on the World Wide Web for further study. These databases contain hundreds of smaller trees that show the relationships among groups of species as broad as all mammals or as narrow as a single genus of sunflowers.

Michael Sanderson, assistant professor of evolution and ecology, and Michael Donoghue, director of the Harvard University Herbaria, planted TreeBASE on the Web this year. So far, the researchers have entered data for 400 trees from about 150 studies. These are mostly green plants because of the researchers' botany backgrounds.

"We have hundreds of relatively small subtrees," says Sanderson. "Presumably, one true tree links them all together. We've been working on ways to get to that one tree."

Researchers investigate where the brain detects and stores novel events

Whether it's the office holiday party where the boss got drunk or the time dad fell off the ladder while painting the living room ceiling, the brain pays particular attention to novel events and files them away for future reference. That's why our most memorable experiences are often those where an extraordinary event occurred.

In a recent paper in the weekly journal Nature, Center for Neuroscience researcher Robert Knight proposed that a region of the brain called the hippocampus may play a crucial role in detecting novelty. Knight's interest arose from his clinical observations that some of his amnesiac patients "seemed a bit 'flat' compared to others with respect to their normal arousal levels," he says.

When Knight investigated the source, he found that damage in the hippocampal region resulted in a markedly reduced ability to respond to novelty. By recording the electrical patterns of different regions of the brain, Knight found a slower response in brains with damaged hippocampi to novel stimuli--sound, touch, and images--although their brains' responses to the expected stimuli was preserved.

"The results present a new perspective on how memories are acquired and stored," Knight says.

Reference: Knight RT. 1996. Nature 383(6597):256-159.