image: In C. elegans, NHR-49 helps mediate a remarkable process employed by sexually mature adults to extend longevity during long periods of starvation. First, the reproductive system is shut down, meaning that ovulation and generation of mature eggs is halted. This reproductive arrest is dependent on NHR-49. Second, after arrest, all of the mature eggs, as well as immature eggs, are actively killed and cleaned out of the ovary, leaving only a small population of stem cells that are rigidly protected for extremely long periods of starvation. NHR-49 participates in this process also, by helping to clean dead cells out of the ovary. After restoration of a normal diet, the protected stem cells become active and generate young and fertile eggs. This recovery occurred in animals up to 15 times as old as a well-fed worm in its reproductive prime. In essence, extremely old worms were able to generate new eggs and produce healthy offspring, the authors say. This image relates to an article that appeared in the August 27, 2009, issue of Science Express, published by AAAS. The study, by Dr. G. Angelo at Fred Hutchinson Cancer Research Center in Seattle, Wash., and colleagues, was titled, "Starvation Protects Germline Stem Cells and Extends Reproductive Longevity in C. elegans." view more
Credit: Image © Science/AAAS