Bacteria don't simply move randomly, but swwim toward favorable and away from unfavorable environments. For example, certain chemicals (usually nutrients) attract them while others (usually noxious) repel them. The phenomena of attraction and repulsion of bacteria by chemicals are known as positive and negative chemotaxis, respectively. The occurrence of chemotaxis implies that the organisms have one or more mechanisms for sensing chemicals as well as mechanisms for converting the sensory information into patterns of beating of their flagella, the organs responsible for their swimming behavior. In this respect, bacterial chemotaxis is a model for chemical sensing (taste and smell) in higher organisms, in which chemicals in the environment are detected in cells specialized to be able to respond to them. This project is an attempt to develop an understanding of the mechanisms by which sensory information is detected in bacterial cells, and of the mechanism by which the activity of the flagellae is linked to this information. The results will have relevance to understanding behavior and sensory detection in higher organisms as well as in bacteria, and will also contribute to our knowledge of molecular biology of membranes and cell surface receptors in general.
