[Ultrastructure of Thiocapsa roseopersicina under various cultivation conditions]

The cells of the purple sulphur bacterium Thiocapsa roseopersicina, strain BBS, growing in the light and in the darkness, contain chromatophores of the normal vesicular type. The amount and dimensions of the vesicules in the cells depend on the composition of the medium and the conditions of cultivation. During anaerobic growth of the bacterium in the light in the medium with pyruvate, large cells appear with complicate invaginations of the cytoplasmic membrane. The cells may contain, besides drops of sulphur, polyphosphates, and poly-beta-hydroxybutyric acid, spherical inclusions of a fine-grain structure.