Water is essential for life. Soil organisms have to deal with an inconstant world where water levels can change dramatically in a short period. One day everything is going swimmingly and a month later their world is a dried out mud pit. In this 2-week long project, students will study the response of the soil nematode C. elegans to osmotic stress (high salt levels). Biologists often learn a lot about how something works by breaking or disrupting it and seeing what happens. We will take this approach. First, we will examine the response of normal worms as well as mutants selected for their ability to survive desiccation. Then, employing a combination of bioinformatics, molecular biology, cell biology, and developmental biology, the students will dissect the genetic pathway that worms invoke when confronted with osmotic stress. Students will learn to clone genes from C. elegans and they will employ a novel technology, called RNA interference (RNAi), to disrupt the function of these genes in worms. Because RNAi acts to reduce RNA levels in a gene-specific manner, this technique allows us to systematically test the role of any particular gene in which we are interested. We will use RNAi to study the response of the worms to osmotic stress. In addition to its utility in studies of cellular and developmental biology, RNA interference is being tested as a therapy for viral infections (like HIV), cancers, and other diseases.