Characterization of three spiral-shaped purple nonsulfur bacteria isolated from coastal lagoon sediments, saline sulfur springs, and microbial mats: emended description of the genus Roseospira and description of Roseospira marina sp. nov., Roseospira navarrensis sp. nov., and Roseospira thiosulfatophila sp. nov.

Three new spirilloid phototrophic purple nonsulfur bacteria were isolated in pure culture from three different environments: strain CE2105 from a brackish lagoon in the Arcachon Bay (Atlantic coast, France), strain SE3104 from a saline sulfur spring in the Pyrenees (Navarra, Spain), and strain AT2115 a microbial mat (Tetiaroa Atoll, Society Islands). Single cells of the three strains were spiral-shaped and highly motile. Their intracellular photosynthetic membranes were of the vesicular type.