Page:Bergey's manual of determinative bacteriology.djvu/104

 size, and the differences appear to be far from constant. The ovoid cells of Thiovulum majus are noted as being 11 to 18 microns long and 9 to 17 microns wide, while Thiovulum minus comprises the smaller forms from 9.6 to 11.0 microns long by 7.2 to 9.0 microns wide. In view of the regular occurrence of all intermediate sizes, it seems best to recognize only a single species at present.

The type species is Thiovulum majus Hinze.

1. Thiovulum majus Hinze, 1913. (Hinze, Ber. d. deutsch. bot. Ges., 31, 1913, 195; including Thiovulum minus Hinze, loc. cit.; Thiovulum mulleri Lauterborn, Verhandl. Naturhist.-medizin. Vereins, Heidelberg, N. F., 13, 1915, 414.)

ma′jus. L. comp. adj. major larger. Unicellular organisms, spherical to ovoid. Cytoplasm often concentrated at one end of the cell, the remainder being occupied by a vacuole. Multiplication by constriction which, in late stages, merges into fission. Size of cells, 5 to 20 microns in diameter.

The most characteristic feature is its motility; it is the only one of the spherical to ovoid, colorless sulfur bacteria capable of rapid movement. Flagellation has not been definitely demonstrated, but the type of locomotion suggests the presence of polar flagella.

Normally contains sulfur droplets in cytoplasm, frequently concentrated at one end of cell.

Microaerophilic; apparently requires hydrogen sulfide.

Habitat: Found in sulfide-containing water, usually accumulating near the surface. Often found in cultures of decaying algae and in both fresh-water and marine environments.

(Vislouch, Jour. de Microbiologie, 1, 1914, 50; Sulfospirillum Kluyver and van Niel, Zent. f. Bakt., II Abt., 94, 1936, 396; Thiospirillum Janke, Allgem. Tech. Mikrobiol., I Teil, 1924, 68; not Thiospirillum Winogradsky, Schwefelbakterien, Leipzig, 1888, 104.)

Thi.o.spi′ra. Gr. noun thium sulfur; Gr. noun spira a coil; M.L. fem. n. Thiospira sulfur coil or spiral.

Colorless, motile, slightly bent, large rods, somewhat pointed at the ends, with granules of sulfur within the cells and a small number of flagella at the ends.

The type species is Thiospira winogradskyi (Omelianski) Vislouch.

I. Large spirilla containing numerous sulfur granules.

II. Clear center of spirilla cells contains two, occasionally one or three, sulfur granules.

1. Thiospira winogradskyi (Omelianski, 1905) Vislouch, 1914. (Thiospirillum winogradskyi Omelianski, Cent. f. Bakt., II Abt., 14, 1905, 769; Vislouch, Jour. de Microbiologie (Russian), 1, 1914, 50.)

wi.no.grad′sky.i. M.L. gen. noun winogradskyi of Winogradsky; named for S. N. Winogradsky, a Russian bacteriologist.

Large sulfur spirilla, somewhat pointed at the ends, 2.0 to 2.5 by 50 microns. Numerous granules of sulfur. Very motile, with one to two polar flagella.

The large, very active sulfur spirillum found by Gicklhorn (Cent. f. Bakt., II Abt., 50, 1920, 418) may have belonged to this species.

Habitat: Curative mud.

2. Thiospira bipunctata (Molisch, 1912) Vislouch. 1914. (Spirillum bipunctatum