Reisolation of Nitrosospira briensis S. Winogradsky and H. Winogradsky 1933

Summary

Nitrosospira briensis was isolated from the soils of Crete, the Greek mainland and Switzerland. This is only the second report of the reisolation of a member of this genus since it was described by the Winogradskys in 1933. N. briensis, studied in the present investigation, is so tightly coiled that the cells appear as rods or cylinders rather than spirals when examined with the phase- contrast microscope. On occasion the cells partially uncoil and the spirals are clearly evident even with a phase-contrast microscope. When the cells were thin-sectioned, shadowed, negatively-stained or freeze-etched and viewed with the electron microscope, the spirals were visible even in tightly coiled cells. The tightly coiled cells which appear as rods or cylinders are 1.5–2.5 μ long and 0.8–1.0 μ wide. The cells moved erratically and are propelled by 1–6 flagella which were 3–5 μ long.