82 



ORDER I. PSEUDOMONADALES 



size, and the differences appear to be far from constant. The ovoid cells of Thiovulum majiis 

 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 muUeri 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 mo- 

 tility; 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 cyto- 

 plasm, frequently concentrated at one end 

 of cell. 



Microaerophilic ; apparently' requires hj^- 

 drogen sulfide. 



Habitat: Found in sulfide-containing 

 water, usually accumulating near the sur- 

 face. Often found in cultures of decaying 

 algae and in both fresh-water and marine 

 environments. 



Genus IV. Thiospira Vislouch, 1914* 



(Vislouch, Jour, de Microbiologic, 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. 



Key to the species of genus Thiospira. 



I. Large spirilla containing numerous sulfur granules. 



1. Thiospira winogradskyi. 



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



2. Thiospira bipunctata. 



1. Thiospira winogradskyi (Omelian- 

 ski, 1905) Vislouch, 1914. (Thiospirillum 

 winogradskyi Omelianski, Cent. f. Bakt., II 

 Abt., 14, 1905, 769; Vislouch, Jour, de Mi- 

 crobiologic (Russian), 1, 1914, 50.) 



wi.no.grad'sky.i. M.L. gen. noun wino- 

 gradskyi 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. (Svirillum bivunctatum 



. Thiospira bipunctata (Molisch, 1912) 

 louch, 1914. {Spirillum bipunctatum 



* Prepared by Prof . Dr. Alexander Janke, Technische Hochschule, Vienna, Austria, De- 

 cember, 1954. 



