RUI: Genomic Analysis of Metabolic Regulation in Caulobacter

Santa Clara University, Santa Clara CA

Investigators

Abstract

A grant has been awarded to Dr. Craig Stephens of Santa Clara University to study the strategies bacteria use to coordinate their metabolism and growth in response to nutrients available in their environment. Some microbes thrive in habitats with very low nutrient levels, having evolved very efficient ways to scavenge food from their surroundings. The freshwater bacterium Caulobacter crescentus is typical of such microbes. Caulobacter, a non-pathogenic freshwater microbe, has been studied intensively because of its distinctive life cycle. Caulobacter cells alternate between a mobile, non-dividing cell (the "swarmer") and a stationary cell (the "stalked" cell) that attaches to solid surfaces and reproduces. This organism is unique among bacteria in that cells at a specific stage of the cell cycle (swarmer cells) can be isolated and studied as they proceed through the remainder of the cell cycle, developing into stalked cells and reproducing. Dr. Stephens and his laboratory group will examine physiological and genetic regulatory strategies that enable Caulobacter to survive and thrive at low nutrient levels, and will collaborate with scientists at Stanford and Harvard Universities to use microarray technology (capable of measuring the activity of thousands of genes simultaneously) to understand how Caulobacter controls its metabolism as it progresses through its life cycle. These studies are designed to help us understand how microbes control genes during growth and reproduction, how they acquire nutrients when there is very little food available, and how these processes intersect. Many marine, freshwater, and terrestrial habitats have very low nutrient levels, and microorganisms are generally the dominant life forms in such habitats. Understanding the behavior of these microbes is important for understanding nutrient cycling, the effects of pollution, and the potential for bioremediation. At a more basic level, regulatory networks controlling the bacterial cell cycle are poorly understood, and how they interact with central metabolism is essentially a black box. Exploration of this field may identify new paradigms for cellular systems engineering, and help identify new targets for antimcrobial drugs.