Unlike well studied bacteria such as Eschericia coli, the membrane potential of Spirochaeta aurantia is involved in chemotaxis. Furthermore the flagellar filaments of the spirochete periplasmic flagella are relatively complex when compared with the exoflagella of other bacteria. The goal of the proposed research is to understand the molecular basis of the mechanisms of motility and chemotaxis unique to spirochetes. Genes required for motility will be cloned and analyzed. A considerable effort toward developing a gene transfer system for this organisms will be mounted. The immediate use of such a system will be in studies of spirochete motility and chemotaxis. Techniques for studying ionic channels in the membranes of S. aurantia will be developed with an ultimate goal of identifying chemoeffector-regulated channels. Spirochetes are motile bacteria that have periplasmic flagella rather than exoflagella. Cells exhibit smooth swimming, reversals of cell orientation and flexing. At least some spirochetes also can "crawl" on solid surfaces. The peculiar mechanism of spirochete motility is important to the success of these organisms in the viscous environments in which they trive. The proposed research will employ Spirochaeta aurantia as a model in studies of motility and chemotaxis of spirochetes and in the development of techniques generally useful for studies of spirochetes. The results of this research should provide new information concerning the relationship of the unique spirochete motility system to their behavior.
