Ultrastruct of Methylosinus trichosporium as revealed by freeze etching.

The methane-oxidizing bacterium Methylosinus trichosporium forms extensive intracytoplasmic membranes that lie near the cell periphery and paralled to it. These membranes enclose cavities within the cytoplasm and exist as flattened, balloon-like vesicles. The internal membranes are passed along to both cells during budding. The bacteria accumulate poly-beta-hydroxybutyrate granules that lie in the center of the cells, neither within the internal membrane vesicles nor attached to them. Intercellular bridges result in the formation of chains of bacteria two to four cells in length.