[Macromolecular subunits on the surfaces of the cell wall of Thiocapsa roseopersicina]

A layer of fungiform macromolecular subunits was found on the surface of the cell wall of Thiocapsa roseopersicina, a purple sulphur bacterium, strain BBS. The cap of a particle has a diameter of 40 to 60 A; the stalk is 80 to 100 A long and 20 to 30 A thick. Under the conditions of nitrogen fixation and a low content of vitamin B12 (0.1 mcg/litre) in the cultural broth, a second layer of similar particles is formed over the first layer.