870 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



ibid., 455; Chloropseudomonas? Czurda and Maresch, Arch. f. Mikrobiol., 8, 1937, 

 123; in part, Pelogloea Lauterborn, Verhandl. naturhistor.-medizin. Vereins, Heidel- 

 berg, N.F. 13, 1915, 430.) From Greek Mows, green and bios, life. 



Green sulfur bacteria, occurring singly or in chains, individual cells of various 

 sizes and shapes, from spherical to relatively long rod-shaped, the latter sometimes 

 coiled into tight spirals; often united in chains, and generally embedded in a slime 

 capsule. Non-motile. Contain a chlorophyllous pigment diiferent from the com- 

 mon green plant chlorophylls and from bacterio-chlorophyll. Capable of photosyn- 

 thesis in the presence of hydrogen sulfide, during which they produce elementary 

 sulfur which is excreted outside the cells. Do not form spores. 



The type species is Chlorobium limicola Nadson. 



1. Chlorobium limicola Nadson. 

 (Nadson, Bull. Jard. Imper. Botan., St. 

 P^tersb., 12, 1912, 64 (Russian), S3 

 (German) ; Chloronostoc abbreviation Pas- 

 cher, Siisswasserfiora Deutschlands, 

 Osterreichs und der Schweiz, Jena, 

 13, 1925, 456; Tctrachloris inconstans 

 Pascher, ibid., 456; SorocJdoris aggre- 

 gata? Pascher, ibid., 455; in part Pelo- 

 gloea chlorina Lauterborn, Verhandl. 

 naturhistor.-medizin. Vereins, Heidel- 

 berg, N.F. 13, 1915, 430.) From Latin, 

 mud-dweller. 



Cells: Various shapes and sizes, mark- 

 edly dependent upon environmental 

 conditions. In young and healthy state 

 predominantly spherical to ovoid, about 

 0.5 to 1 micron in diameter, frequently 

 united in chains resembling streptococci. 

 Often cells become elongated and appear 

 as rods, generally about 0.7 micron by 

 1 to 2.5 microns; also these may remain 

 united in chains. Regularly produce 

 mucus, causing the formation of cell- 

 conglomerates of different size and shape, 

 but not, as a rule, of characteristic 

 appearance. 



Color yellowish-green. Non-motile. 



Abnormal cell forms (involution 

 forms) rather common. These may be 

 larger spherical cells, up to 5 to 6 microns 

 in diameter, the larger ones generally 

 vacuolated, or long rods, occasionally 

 club-shaped but more often coiled. In 

 rare cases the latter may be loosely 

 wound. More frequently they are 

 tightly-coiled screws, with cells of about 

 0.5 micron in diameter by as much as 15 

 microns in length. The spherical in- 

 volution forms are normally encountered 

 in acid, the coiled ones in alkaline en- 

 vironments. 



Strictly anaerolnc and apparently 

 dependent upon hydrogen sulfide and 

 light. Development in organic media 

 has not been obtained. 



Habitat: Mud and stagnant water con- 

 taining rather high concentrations of 

 hydrogen sulfide and exposed to light; 

 more rarely in sulfur springs. 



Illustrations: Nadson, loc. cit., PI. Ill, 

 fig. 3-12; van Niel, Arch. f. Mikrobiol., 

 3, 1931, 66, fig. 8. 



Genus II. Pelodictyon Lauterborn. 



(Lauterborn, AUgem. botan. Ztschr., 19, 1913, 98; Verhandl. naturhistor.-medizin. 

 Vereins, Heidelberg, N.F. 13, 1915, 431; Schmidlea loc. cit., Lauterborn, Allgem. 

 botan. Zeitschr., 19, 1913, 97; in part, Pelogloea Lauterborn, Verhandl. naturhist. 

 medizin Vereins, Heidelberg, N.F. 13, 1915, 430; Pediochloris Geitler, Die Susswasser- 

 flora Deutschlands, Osterreichs und der Schweiz, Jena, 12, 1925, 457.) From Greek 

 pelos, mud and dictyon, net. 



Green sulfur bacteria, individual cells ovoid to distinctly rod-shaped, producing 

 rather extensive mucoid capsules, and generally united into large colonies of char- 

 acteristic shapes. Non-motile. Contain chlorophyllous pigments different from 



