1006 MANUAL OF DETERMIXATIVE BACTERIOLOGY 



Members of the genus Sporocytophaga are not known to produce fruiting bodies as 

 such, but often dense agglomerations of shortened rods or cocci have been noted; 

 these may be interpreted as primitive forms of fruiting bodies. 



Physiologically most species show great similarity, preferring substrates rich in 

 cellulosic or other complex carbohydrate materials. 



Most of the known species are saprophytic or coprophilic and may be found on 

 dung, in soil, on rotten wood, straw, leaves, etc. They frequently appear to live in 

 close association with various true bacteria and are probably parasitic on them. 

 Many have been cultivated on dung. One species is aquatic and parasitic on an alga, 

 Cladophora sp. (Geitler, Arch. f. Prostistenol., 50, 1924, 67). One is parasitic (?) 

 on lichens and some are halophilic marine forms (Stanier, Jour. Bact., 40, 1940, 623). 

 Another species is reported as pathogenic for fish (Ordal and Rucker, Proc. Exper. 

 Biol, and Med.. 56, 1944, 15). 



Culture media. The myxobacteria are frequently cultured by transferring to dung. 

 For certain species sterilized dung has been reported as less favorable than the un- 

 sterilized. Dung decoction agar has often been employed. Among the early investi- 

 gators, Quehl (Cent. f. Bakt., II, Abt., 16, 1906, 9) secured slow growth of some species 

 on malt extract-gelatin at 18° to 20°C with digestion of the gelatin. Potato-nutrient 

 agar was reported better than dung agar, while no growth occurred on sterilized potato 

 alone. Peptone was considered necessary; glucose had little effect. Pinoy (Comp. 

 rend. Acad. Sci., Paris, 157, 1913, 77) claimed that satisfactory development of Chon- 

 dromyces crocatus depended upon the presence of a species of Micrococcus in the 

 medium. Kofler (Sitzber. d. k. Akad. Wiss., Wien, Math. Nat. Klasse, 122 Abt., 

 1913, 845) successfully used a sucrose-peptone agar to which was added potassium 

 and magnesium salts. 



Recent evidence indicates that the carbon requirements of these organisms are 

 met satisfactorily by the more complex carbohydrates, and frequently by their prod- 

 ucts of hydrolysis. Mishustin (Microbiology, Moscow, 7, 1938, 427), Imsenecki 

 and Solntzeva (Microbiology, Moscow, ^, 1937, 3), Krzemieniewski and Krzemieniew- 

 ska (Acta Soc. Bot. Pol., 5, 1927, 102) and others have reported good growth of several 

 species of myxobacteria on cellulose. 



Beebe (Jour. Bact., 40, 1940, 155) claimed several species to be facultative parasites 

 on various true bacteria. Good gi-owth was obtained on suspensions of killed bacterial 

 cells in 1.5 per cent agar. Sniesko, Hitchner and McAllister (Jour. Bact., 4i, 1941, 

 26) showed the destruction of living bacterial colonies by colonies of myxobacteria. 



Temperature range. Most species cultivated in the laboratorj^ show a minimum 

 between 17° and 20°C though some species grow at 10°C. Maximum growth usually 

 occurs at about 35°C and the maximum growth temperature is about 40°C. More 

 normal fruiting bodies are produced at lower temperatures. 



The Krzemieniewskis (Acta Soc. Bot. Pol., 5, 1927, 102) report that the fruiting bodies 

 of Melittangium boletus, Myxococcus virescens, Chondrococcus coralloides, Archangium 

 gephyra and Archangium. primigenium var. assurgens first develop, followed by Poly- 

 angium fuscum and P. fuscum var. vclalum. At 30°C they appear in about 5 to 7 days, 

 at 17° to 20°C in 8 to 12 days, and at 11° to 14°C in 24 to 30 days. Each 10°C rise in 

 temperature approximately halves the time. Other species are slower in developing. 



The vegetative rods. The vegetative cells are long, flexuous rods, often 30 times 

 as long as broad. Thaxter noted rods up to 15 microns in length though these appear 

 abnormally long. In general the cells are cylindrical, more rarely tapered or pointed 

 at the ends. Jahn (1924, loc. cit.) described spindle-shaped cells. Thaxter (Bot. 

 Gaz., 37, 1904, 405) believed that a highlj^ elastic wall was present ; other authors have 



