General Information: Rhodospirillum centenum, also called Rhodocista centenaria, is a nitrogen-fixing photoheterotroph with a complex life cycle. R. centenum is one of the few known thermotolerant purple bacteria species with optimal growth temperature of 44 dgrees C and a maximal growth temperature of 48 degrees C. In liquid media this organism is motile by a single polar flagellum. R. centenum produces lateral flagella to become a swarming cell. Under low nutrient conditions R. centenum forms a desiccation- and UV-resistant cyst. R. centenum can often be cultivated from hot springs such as those found at Yellowstone National Park. R. centenum is emerging as a model organism for genetic and molecular genetic analysis of cyst formation.