If you were twirling double-dutch ropes and someone shook the ropes back and forth from the middle, you and your partner would be pulled together. These are the kinds of large-scale behaviors of cellular polymers that David Weitz studies at Harvard University.To measure the flexibility of actin, Weitz and his colleagues exploited the stiffness of scruin, a glue-like protein that holds the actin fibers together.1 In this scenario, "the joints are stiffer than the fibers, so the properties of the

© Eye of Science/Photo ResearchersWhen a yeast cell falls onto an apple in the spring, life is good. Plentiful food and good weather maintain growth and division. But the good times don't last forever. "When resources dwindle due to competition, it makes sense to kill the less fit cells," says Frank Madeo of the Institute for Physiological Chemistry in Tübingen, Germany.Madeo and colleagues have mimicked the apple scenario in cultures to show that old Saccharo myces cerevisiae cells vo

Courtesy of Jason KuslerA quarterback decides where to throw the football based on the field's layout and the players' positions on it. Scanning the field, he sees loads of images that help him make his split-second decisions. He actually views even more that he may not recall.René Marois of Vanderbilt University, Nashville, Tenn., and colleagues study the delicate balance between seeing, registering, and recalling images in the visual field. If images come faster than two per second, subje

James King-Holmes/Science Photo LibraryIn the world of life-extending therapies, a lobotomy doesn't sound like an attractive option, but for the nematode Caenorhabditis elegans, destruction of particular sensory neurons can extend, or reduce, lifespan by as much as 30%. Joy Alcedo and Cynthia Kenyon at the University of California, San Francisco, have used a laser to kill individual neurons; they suggest that what may be happening to modify the lifespan of worms may also be at play in higher org