FAMILY V. MYXOCOCCACEAE 



891 



des. M.L. mas.n. Myxococcus a generic name; 

 Gr. noun eidus shape; M.L. adj. myxococ- 

 coides resembling Myxococcus. 



Vegetative cells: Flexible, singly occur- 

 ring rods, 0.3 to 0.4 by 2.5 to 8.0 microns. 

 Gram-negative. Young cells stain uniformly 

 with basic dyes, but with the onset of micro- 

 cyst formation, chromatin becomes con- 

 centrated in central bands or spots in the 

 shortening rods. 



Microcysts: Spherical, varying in size 

 from 1.2 to 1.6 microns. Surrounded by a 

 highly refractile wall. 



Produces glistening, light yellow patches 

 on filter paper-silica gel or -agar plates 

 after 4 to 5 days. The central areas gradually 

 become translucent owing to complete de- 

 struction of the cellulose. Old cultures as- 

 sume a brownish tinge. 



On mineral glucose agar plates, colonies 

 are small, pale yellow and translucent; they 

 may be round with even edges or flat and 

 irregular. The agar under the colony be- 

 comes etched and sunken. 



Cellulose, cellobiose and glucose are uti- 

 lized. Mannose utilized by some strains 

 (Kaars Sijpestein and Fahraeus, Jour. Gen. 

 Microbiol., 3, 1947, 232). Xylose, arabinose, 

 galactose, fructose, mannitol and starch 

 not utilized. 



Ammonia, nitrate, urea, peptone and 

 yeast extract can serve as nitrogen sources. 



Catalase-positive. 



Strictly aerobic. 



Optimum temperature, 30° C. 



Source: Isolated from soil. 



Habitat: Soil. Decomposes cellulose. 



2. Sporocytophaga congregata Fuller 

 and Norman, 1943. (Jour. Bact., 45, 1943, 

 567.) 



con.gre.ga'ta. L. part. adj. congregatus 

 assembled. 



Vegetative cells: Long, flexuous rods with 

 pointed ends, 0.5 to 0.7 by 5.5 to 8.0 microns. 



Microcysts: Spherical, 0.7 to 1.1 microns 

 in diameter. Usually occur in localized re- 

 gions within the colony. 



Growth on starch agar is smoky, later 

 turning yellow. Colonies are irregularly 

 round, slightly concave. Edge is smooth 

 and entire at first, later becoming irregular. 

 Marginal and internal swarming may be 

 prominent. The vegetative cells gather into 



groups, and in these regions a large number 

 of spherical spores are found. 



Growth on cellulose dextrin agar is pale; 

 colonies are small and concave. Hollowing 

 of the agar is limited to the area of colony 

 growth. 



Litmus milk: Growth, but no digestion or 

 curd formation. 



Indole not produced. 



Glucose, galactose, lactose, maltose, su- 

 crose, arabinose, calcium gluconate, starch, 

 cellulose, dextrin, pectin and hemicellulose 

 are utilized. Filter paper is not attacked. 



Ammonium, nitrate and peptone are suit- 

 able nitrogen sources. 



Nitrites not produced from nitrates. 



Highly aerobic. 



Optimum temperature, between 25° and 

 30° C. 



Source: Isolated from soil. 



Habitat: Soil. Decomposes organic mat- 

 ter. 



3. Sporocytophaga ellipsospora (Im- 

 senecki and Solntzeva, 1936) Stanier, 1942. 

 {Cytophaga ellipsospora Imsenecki and Soln- 

 tzeva, Bull. Acad. Sci. U.S.S.R., Ser. Biol., 

 No. 6, 1936, 1137; Stanier, Bact. Rev., 6, 

 1942, 153 and 190.) 



el.lip.sos'po.ra. Gr. noun ellipsis ellipse; 

 Gr. noun spora seed; M.L. noun spora spore; 

 M.L. adj. ellipsosporus with elliptical 

 spores. 



Vegetative cells: Flexible, singly occur- 

 ring rods, 0.4 microns wide at the center and 

 tapering to both ends. Length, 7.5 microns. 

 May be straight, bent U-shaped or 

 S-shaped. 



Microcysts: Ellipsoidal or somewhat elon- 

 gated, 0.9 to 1.2 by 1.6 to 1.8 microns. Al- 

 most always situated in closely packed ag- 

 gregates; isolated, individual microcysts 

 rare. Germinate by elongation. 



On mineral salts-silica gel plates covered 

 with filter paper, orange, glistening, mu- 

 cilaginous patches are produced. Ultimately 

 the filter paper is completely dissolved, and 

 the patches become translucent. 



Ammonia, nitrate and peptone can serve 

 as sources of nitrogen. 



Strictly aerobic. 



Optimum temperature, between 28° and 

 30° C. 



Source: Isolated from soil. 



Habitat: Soil. Decomposes cellulose. 



