846 MANUAL OF DETERMINATIVE BACTERIOLOGY 



Issatchenko (Etudes microbiologiques Habitat: Mud and stagnant water, con- 



des Lacs de Boue, Leningrad, 1927, 113- taining hydrogen sulfide, and exposed 



114) recognizes a forma 7ninus and a to light; sulfur springs, 



forma magna, differentiated mainly by Illustrations: Winogradsky, loc. cit., 



the size of the individual rods. Plate III, fig. 13-17. 



Genus V. Thiothece Winogradskij. 



(Winogradsky, Schwefelbacterien, Leipzig, 1888, 82; ThiosphaeraM'iyoshi, Jour. 

 Coll. Sci., Imp. Univ. Tokj^o, Japan, 10, 1897, 170.) From Greek thcion, sulfur and 

 theke, container. 



Purple sulfur bacteria which, in their growth characteristics, resemble the blue- 

 green alga Aphanothece. Cells spherical to relatively long cylindrical-ellipsoidal, 

 embedded in a gelatinous capsule of considerable dimensions. Following cell divi- 

 sion the daughter cells continue to secrete mucus which causes the individual bac- 

 teria to remain clearly separated by an appreciable distance; the common capsule 

 thus appears only loosely filled. The cells may become activelj^ motile and separate 

 themselves from the colony. Such swarmers closely resemble the cells of certain 

 species of Chromatium. Contain bacteriochlorophyll and carotenoid pigments. Ca- 

 pable of photosynthesis in the presence of hydrogen sulfide, producing elementary 

 sulfur as an intermediate oxidation product which is stored as sulfur globules inside 

 the cells. 



The type species is Thiothece gelalinosa Winogradsky. 



1. Thiothece gelatinosa Winogradsky. to cylindrical. Color of individual cells, 



(Winogradsky, Schwefelbacterien, Leip- faint, often grayish-violet, or even dirty 



zig, 1888, 82; Thiosphaera gelatinosa yellowish. Sulfur globules usually de- 



Miyoshi, Jour. Coll. Sci., Imp. Univ. posited in outermost layers of proto- 



Tokyo, Japan, 10, 1897, 170; Lampro- plasm, and generally small. 



cystis gelatinosa Migula, Syst. d. Bakt., Habitat : Mud and stagnant water con- 



2, 1900, 1044; Chromatium sphaeroides ^^^^.^^^ hvdrogen sulfide anrl exposed to 



Hama, Jour. Sci. Hiroshmia Univ., Ser. ,. , , .\ 



B, Div. 2, Bot., i, 1933, 158.) From l^ght; sulfur springs. 



Latin geki^-o, freezing, indicating solidi- Illustrations: Winogradsky, loc. cit., 



fication or clumping. PI- III» ^S- 9-12; Miyoshi, loc. cit., PI. 



Cells: 4 to 6 by 4 to 7 microns, spherical XIV, fig. 25. 



Genus VI. Thiocystis Winogradsky. 



(Schwefelbacterien, Leipzig, 1888, 60.) From Greek theion, sulfur and kystis, sac, 

 bladder. 



Purple sulfur bacteria which form compact colonies, many of which may be loosely 

 embedded in a common gelatinous capsule. Individual cells spherical to ovoid, 

 often diplococcus-shaped. Colonies may emerge as more or less large units from out 

 of the common capsule and break up afterwards, sometimes into single swarmers; 

 or the aggregates may split up inside the original capsule, and release small motile 

 units or single swarmers. In pure cultures frequently developing as single cells and 

 diplococci. Produce bacteriochlorophyll and carotenoid pigments, coloring the 

 cell masses purplish to red. Capable of photosynthesis in the presence of hydrogen 

 sulfide, whereby elementary sulfur is formed as an intermediate oxidation product 

 which is deposited as droplets inside the cells. 



