Page:Bergey's manual of determinative bacteriology.djvu/64

 The type species is Thiodictyon elegans Winogradsky.

1. Thiodictyon elegans Winogradsky, 1888. (Schwefelbacterien, Leipzig, 1888, 80.)

e′le.gans. L. adj. elegans choice, elegant.

Rods 1.5 to 1.7 by 2.5 to 5 microns; or longer just prior to cell division. Usually contain a large pseudovacuole (aerosome), leaving a rather thin protoplasmic sheath along the cell wall.

Sulfur droplets generally quite small; deposited exclusively in the thin protoplasmic layer.

Issatchenko (Études microbiologiques des Lacs de Boue, Leningrad, 1927, 113-114) recognizes a forma minus and a forma magna, differentiated mainly by the size of the individual rods.

Habitat: Mud and stagnant water containing hydrogen sulfide and exposed to light; sulfur springs.

Illustrations: Winogradsky, ''loc. cit.'', Plate III, fig. 13-17.

Thi.o.the′ce Gr. noun thium sulfur; Gr. noun thece a box, chest; M.L. fem. n. Thiothece sulfur box.

Sulfur purple 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 division the daughter cells continue to secrete mucus which causes the individual bacteria to remain clearly separated by an appreciable distance; the common capsule thus appears only loosely filled. The cells may become actively motile and separate themselves from the colony. Such swarmers closely resemble the cells of certain species of Chromatium. Contain bacteriochlorphyll and carotenoid pigments. Capable of photosynthesis in the presence of hydrogen sulfide, producing elemental sulfur as an intermediate oxidation product which is stored as sulfur globules inside the cells.

The type species is Thiothece gelatinosa Winogradsky.

1. Thiothece gelatinosa Winogradsky, 1888. (Schwefelbacterien, Leipzig, 1888. 82.)

ge.la.ti.no′sa. L. part. adj. gelatus frozen, stiffened; M.L. noun gelatinium gelatin, that which stiffens; M.L. adj. gelatinosus gelatinous.

Cells 4 to 6 by 4 to 7 microns, spherical to cylindrical. Color of individual cells, faint, often grayish violet or even dirty yellowish. Sulfur globules usually deposited in outermost layers of protoplasm and generally small.

Habitat: Mud and stagnant water containing hydrogen sulfide and exposed to light, sulfur springs.

Illustrations: Winogradsky, ''loc. cit.'', Pl. III, fig. 9-12; Miyoshi, Jour. Coll. Sci., Imp. Univ. Tokyo, Japan, 10, 1897, 170, Pl. XIV, fig. 25.

Thi.o.cys′tis. Gr. noun thium sulfur; Gr. noun cystis the bladder, a bag; M.L. fem. n. Thiocystis sulfur bag.

Sulfur purple 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 develop as single cells and diplococci. Produce bacteriochlorophyll