Fine structure of Sarcina maxima and Sarcina ventriculi.

The fine structure of Sarcina maxima and S. ventriculi was studied by electron and phase-contrast microscopy. The two organisms differ mainly with respect to their cell surface. A thick cellulose layer present on the cell wall of S. ventriculi was not observed on the surface of S. maxima. Carbon replication indicated that the outer surface of S. ventriculi is rough in contour, probably as the result of the fibrillar nature of the accumulated cellulose. The cytoplasm of both sarcinae contains inclusions similar to polysaccharide and polymetaphosphate granules. Mesosomes were observed in cells of S. maxima. Packets of S. ventriculi generally comprise a larger number of cells and are more irregularly constructed than those of S. maxima. Cells in large packets of S. ventriculi assume flattened or otherwise irregular shapes, whereas cells of S. maxima maintain a more uniform appearance.