Page:Bergey's manual of determinative bacteriology.djvu/913

 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.