Page:Bergey's manual of determinative bacteriology.djvu/629

 2. No growth on plain agar; brownish yellow pigment produced on soil-extract agar; gelatin not liquefied; no growth at 10° C. 9. Arthrobacler terregens. 1. Arlhrobacter globiforniis (Conn, 1928) Conn and Dimmick, 1947. (Bacterium globiforme Conn, New York Agr. Exp. Sta. Tech. Bull. 138, 1928, 3; also see Conn and Darrow, ibid., 172, 1930, 3; Arthrobacler globiforme (sic) Conn and Dimmick, Jour. Bact., 54, 1947, 295, Fig. 1, and 301.) glo.bi.for'mis. L. noxxnglobus ball, globe; L. novLD. foryna shape; M.L. adj. globijormis spherical. Rods, irregular in shape and size, gen- erally 0.5 to 0.7 by 1.0 to 3.0 microns, oc- curring in an angular arrangement. Cells may be curved, slightly bent or, frequently, swollen; rudimentary branching may occur in liquid media. Coccoid cells, 0.6 to 0.8 mi- cron in diameter, develop in older cultures; larger coccoid cells (cjstites) occur which give rise to rod forms by germination on transfer to fresh media. Non-motile. Gram- negative in young cultures; coccoid forms prevailingly Gram-positive. Gelatin stab: Slow crateriform liquefac- tion, becoming stratiform; liquid clear; abundant sediment. Agar colonies: Circular, up to 1.5 mm in diameter, slightl}' raised, cream-colored, waxy luster. Agar slant: Growth filiform, flat, smooth, cream-colored, soft glistening with metallic sheen. Soil extract agar slant: Growth filiform, flat, pale cream-colored, surface slightly rippled, soft, translucent, glistening, no sheen, lobate edge. Asparagine agar slant: Filiform, flat, smooth, whitish, dull, soft. Broth: Slightly turbid; little or no surface growth; slight sediment. Potato: Growth abundant, pale brown, glistening, soft. Milk: Slow clearing (2 to 3 weeks) without coagulation; alkaline. Indole not produced. Hydrogen sulfide produced in small amounts in cysteine medium. Slight acid but no gas from glucose, su- crose, mannitol and arabinose; no acid or gas from lactose or glycerol. Acetylmethylcarbinol not produced. Starch is hydrolj-zed. Nitrites produced from nitrates. Urease not produced. Utilizes nitrates and ammonium salts as nitrogen sources; citrates utilized as sole source of carbon. Of 19 amino acids tested, none was re- quired for growth; preformed growth factors also were not required (Campbell and Wil- liams, Food Research, 16, 1951, 506). Ammonium chloride and the 19 amino acids which were tested may serve as sources of nitrogen; the amino acids may also be utilized as carbon sources (Campbell and Williams, loc. cit.). Inorganic sulfur may serve as a source of sulfur (Campbell and Williams, loc. cit.). Catalase-positive. Aerobic. Temperature relations: Optimum, about 25° C; good growth from 20° to 32° C; slight growth at 10° C; no growth at 37° C. Source: Isolated from soil. Habitat: Widely distributed in soil. 2. Arthrobacler pascens Lochhead and Burton, 1953. (Can. Jour. Botany, 31, 1953, 7.) pas'cens. L. part. adj. -pascens nourishing. Rods, generally 0.6 to 0.8 by 1.0 to 4.0 microns, occurring in an angular arrange- ment as a result of snapping division. The cells vary in size and shape according to the culture medium: irregular forms, curved, swollen or club-shaped, may be noted as well as a tendency to form short filaments with rudimentary budding, especially in liquid media. Coccoid cells occur by the process of fragmentation, usually within two days. On solid media the cocci are 0.5 to 0.7 micron in diameter, and 0.7 to 0.9 microns in diameter in semisolid or liquid media. On fresh transfer, the large coccoid cells (cystites) germinate and give rise to two or more rod forms. Non-motile. Gram- negative. Gelatin stab: White, viscous surface growth followed by slow liquefaction which