[Age-related changes in the ultrastructure of Anabaena variabilis cells]

The growth and death of the obligate phototrophic cyanobacterium Anabaena variabilis Kütz, strain Lefevre, were studied under stationary conditions in the light. Each growth stage can be characterized by physiological and ultrastructural peculiarities. The following changes have been found in the cells with aging: the rate of oxygen evolution decreases, the photosynthetic lamellae untwist and separate with the formation of intrathylakoid vacuoles, the number of inclusions increases. Irreversible vesiculation of the parachromatophore was observed during the death of the cells. Lysis of the cells was found to be different in the light and in the dark.