white-gray. Spores almost spherical, 1.3 microns in diameter, often arranged in chains. Gelatin colonies: Circular, yellowish. Gelatin stab: Liquefaction. Agar: White aerial mj-celium. Ca-malate agar: Yellowish colonies; gray aerial mycelium. Soluble j'ellow pigment formed. Starch agar: Abundant growth; graj' aerial mycelium. Soluble yellow pigment. Glucose agar: Same as for starch agar. Glucose broth: Coarse, flaky growth. Yellow pigment. Litmus milk: Rapidly coagulated and peptonized. Potato: Colorless growth; aerial mycelium gray. Strong diastatic action. Esculin is hydrolyzed. Cellulose is decomposed. Nitrates show slight reduction. Aerobic. Optimum temperature, between 30° and 35° C. Antagonistic properties: Positive. Source: Isolated from soil. Habitat: Soil. 19. Slreptoniyces rimosus Sobin et al., 1950. (Sobin, Finlay and Kane, U. S. Pat. 2,516,080, July 18, 1950.) ri.mo'sus. L. adj. rimosus full of cracks. Vegetative growth: Flat, smooth colonies with irregular edge; yellow pigment. Aerial mycelium: Limited, ocher-colored in center, colonial-buff at edge; spirals nu- merous; conidia 0.6 to 0.7 by 0.8 to 1.4 mi- crons, cylindrical. Gelatin: Aerial mycelium white. No soluble yellow pigment. No liquefaction. Agar: Poor growth, no aerial mycelium; faint yellowish pigment. Czapek's synthetic agar: Produces very limited growth which is colorless and sub- merged. No aerial mycelium and no soluble pigment. Asparagine agar: Aerial mj-celium white to pallid quaker-drab; faint yellow soluble pigment. Starch agar: Poor, thin growth; aerial mycelium limited; cinnamon-drab colonies. Glucose agar: Growth with dry, cracked surface; aerial mycelium mouse-gray; yel- lowish brown pigment. Milk: Thick pellicle, aerial mycelium grayish white; not peptonized; no change in ph: Potato: Moderate, wrinkled growth; aerial mycelium white to dark; yellowish brown pigment. Starch is weakly hj^drolyzed. Cellulose not decomposed. Nitrites actively produced from nitrates. Odor: Earthy. Antagonistic properties : Produces oxytet- racycline, an amphoteric substance active against various bacteria, rickettsiae and the larger viruses; also produces rimocidin, an antifungal agent. Source: Isolated from soil. Cultural char- acteristics described are those of isolate No. S3279. A culture has been deposited with the Fermentation Division of the Northern Re- gional Research Laboratory, Peoria, Il- linois, permanent collection number NRRL- 2234. Habitat: Soil. 20. Streptoniyces griseoflavus (Krain- sky, 1914) Waksman and Henrici, 1948. {Actinomyces griseoflavus Krainsky, Cent. f. Bakt., II Abt., U, 1914, 662; Waksman and Henrici, in Manual, 6th ed., 1948, 948.) gri.se. o.fla'vus. M.L. adj. yriseus gray; L. adj. flavus yellow; M.L. adj. griseoflavus grayish yellow. Vegetative growth: Thin, cream-colored, later becoming much folded or lichenoid. Aerial mycelium: Powdery, white, appear- ing first on drier edges of growth. Sporo- phores straight, abundantly branched; no curvatures and no spirals produced. Gelatin: Cream-colored to brownish growth, covered with white aerial mycelium. Slow liquefaction, with faint yellowish coloration of the liquefied zone. Agar: Cream-colored growth, covered with white aerial mycelium; no soluble pig- ment. Synthetic agar: Reddish brown to orange growth, covered with white aerial mycelium; faint yellowish soluble pigment. Ca-malate agar: Large colonies covered with yellow to greenish gray aerial my- celium.
