yellowish tinge, becoming brownish, spread- ing. Aerial mycelium thin, white, cottony. Starch agar: Brownish gray growth. Glucose agar: Restricted, brownish growth; center raised. Glucose broth: Sediment consisting of large colonies. Litmus milk: Reaction unchanged; co- agulated; peptonized. Potato: Gray growth with black center. Starch is hydrolyzed. Dark brown pigment formed. Nitrites produced from nitrates. Aerobic. Optimum temperature, 25° C. Antagonistic properties: Some strains produce neomycin or a neomycin-like sub- stance. Source: Isolated from upland and adobe soils in California. Habitat: Soil. 64. Streptomyces netropsis Finlay and Sobin, 1952. (U. S. Pat. 2,586,762, Feb. 19, 1952.) ne.trop'sis. Gr. neut.n. netruni spindle; Gr. fem.n. opsis appearance of something; M.L. adj. netropsis spindle-like. Vegetative growth : Slightly elevated with rough surface and smooth edge and with brown reverse. Aerial mycelium: White. Sporophores on tips of short hyphae in form of whorls or terminal clusters of short hyphae. Conidia short, cylindrical, 0.7 by 1.3 microns. Gelatin: Moderate surface growth. White aerial mycelium. Soluble dark brown pig- ment. No liquefaction. Agar: Moderate to good light brown growth. White aerial mycelium. Soluble light brown pigment. Synthetic agar: Thin, pale olive-buff growth. Aerial mycelium pale vinaceous fawn. No soluble pigment. Glucose asparagine agar: Moderate, wrinkled growth. White aerial mycelium. Soluble brown pigment. Ca-malate agar: Moderate, cream to buff growth. White aerial mycelium. No soluble pigment. Starch agar: Moderate thin growth with pale olive-buff reverse. White aerial myce- lium. No soluble pigment. Glucose agar: Good, dark brown growth. White aerial mycelium. Soluble brown pig- ment. Milk: Poor growth. Not peptonized. Potato: Poor, waxy, wrinkled, brown growth. No aerial mycelium. Dark brown pigment. Starch is actively hydrolyzed. Nitrites not produced from nitrates. Antagonistic properties : Produces a basic antibiotic, netropsin. Source: Isolated from soil near Hudson, New York. Cultural characteristics de- scribed are those of isolate No. 2937-6. A culture has been deposited with the Fer- mentation Division of the Northern Regional Research Laboratory, Peoria, Illi- nois, permanent collection number NRRL- 2268. Habitat: Soil. 65. Streptomyces verticillatus (Kriss, 1938) Waksman, 1953. {Actinomyces verti- cillatus Kriss, Microbiologia, 7, 1938, 111; Waksman, in Waksman and Lechevalier, Actinomycetes and Their Antibiotics, Balti- more, 1953, 75.) ver.ti.cil.la'tus. L. mas.n. verticillus a whorl; M.L. adj. verticillatus whorled. Vegetative growth: Colorless or slightly brownish, smooth or rough colonies. Aerial mycelium: Characteristic primary whorl; formation of straight sporophores. Spores cylindrical, oblong, 0.8 by 1.0 to 1.9 microns. Gelatin: Rapid liquefaction. Agar: Brown growth with no aerial my- celium. Soluble brown pigment. Synthetic agar: Well developed, velvety aerial mycelium, at first white, later dark gray or gray-green. Milk: Coagulated and peptonized. Potato: Soluble brown pigment. Sucrose is inverted. Starch is hydrolyzed. No growth on cellulose. Nitrites rapidly produced from nitrates. Antagonistic properties: Weak. Relationships to other species: Strepto- myces verticillatus viridans is described as a substrain. Source: Isolated from rhizosphere of wheat, Transvolga region, U.S.S.R.
