[Characteristics of the cellular ultrastructural organization of the chemoheterotrophic blue-green alga, Chlorogloea fritschii].

Cellular ultrastructural organization was compared in photoautotrophic and chemoheterotrophic cultures of the blue-green alga Chlorogloea fritschii Mitra. Cells at the fourth stage of the life cycle of the culture in the phase of growth were studied in both cases. The structure of thylakoids was the main object of investigation. The cells of investigation. The cells of Chl. fritschii had a peculiar organization when they were cultivated in the dark on a medium containing glucose as a source of carbon and energy. These cells differed from photosynthetic cells by the structure of the cell wall, cytoplasm, and thylakoids. The cell wall can be entirely or partly absent. The cytoplasm has a lower electron density. The cell wall can be entirely or partly absent. The cytoplasm has a lower electron density. The thylakoids are arranged more random and less compact than in the cells grown in the light. Membranes which form these thylakoids, under identical conditions of fixation, contrasting and microscopy of preparations, look usually as one-layered rather than three-layered. Apparently, the ultrastructure of thylakoids on Chl. fritschii reflects the specificity of energy mechanisms that function in cells in the light and in the dark.