Physiology and evolution of spirochetes.

INTRODUCTION ........................................ 181 METABOLISM OF SPIROCHETES ................................... 182 Cultivation of Spirochetes ................................... 182 Anaerobic Energy-Yielding Metabolism ................................... 183 Aerobic Dissimilatory Metabolism ................................... 187 Physiology of T. pallidum ................................... 189 Lipids and Fatty Acids ................................... 189 Carotenoid Pigments ................................... 191 Motility and Chemotaxis ................................... 191 EVOLUTION OF SPIROCHETES ................................... 194 The Protospirochete Hypothesis ................................... 194 Convergent Evolution Hypothesis ................................... 195 Energy-Yielding Pathways of Spirochetes .................................... 195 Development of Associations with Hosts ................................... 197 Possible Relationship with Gliding Bacteria ................................... 197 Spirochetes, Eucaryotic Flagella, and Cilia ................................... 197 Concluding Remarks ................................... 198 Summary ................................... 198 LITERATURE CITED................................... 199