[Cell cycle characteristics of Chamaesiphon confervicola, a cyanobacterium forming exospores]

A strain of the cyanobacterium Chamaesiphon confervicola was isolated and studied. The strain multiplies by means of exospores, round cells which separate from the parent cell and attach to the substrate with a short pedicle and a mucous pad. The exospore transforms into a cylindrical cell surrounded with a sheath in the process of growth. New exospores separate from the pole of the cell opposite to the pedicle through a rupture in the sheath. Either one exospore or numerous exospores formed as a result of fragmentation of the upper part of the parent cell separate(s) from its end. The mechanism of this process does not differ from that of ordinary cellular division typical of cyanobacteria. The ultrastructure of Ch. confervicola is characterized by the presence of numerous pores in the mureic layer of the cell wall.