flavus, Streptomyces californicus and Strep- tomyces lipmanii, but it is not believed to be identical with any of them. Source: Isolated from soil. Habitat: Soil. 6. Streptomyces coelicolor (Miiller, 1908) Waksman and Henrici, 1948. {Strep- tothrix coelicolor Miiller, Cent. f. Bakt., I Abt., Orig., 46, 1908, 197; Waksman and Henrici, in Manual, 6th ed., 1948, 935.) coe.li'co.lor. L. noun coelurn heaven, sky; L. noun colo7- color; M.L. adj. coelicolor sky-colored. Description by Miiller except as noted. Morphology of Streptomyces coelicolor has not been fully described. According to Waksman and Curtis, who described .4c- tinomyces violaceus -ruber, this is as follows; straight filaments with open, dextrorse spirals. Conidia ellipsoidal or rod-shaped, 0.7 to 1.0 by 0.8 to 1.5 microns. Gelatin: Good growth. No pigment for- mation. Liquefaction fairly rapid, begin- ning in 4 to 7 days. Agar: Good growth. Pigment lacking or faint blue (J. E. Conn, Jour. Bact., 46, 1943, 133). Synthetic agar: Thin, spreading, colorless at first, becoming red, then blue. Aerial mycelium thin, white, powdery, becoming mouse-gray. Asparagine agar: With glycerol as source of carbon, good growth, violet to deep blue, with pigment diffusing through medium; final H-ion concentration, about pH 7.0 to 8.0. With glucose as source of carbon, poorer growth, red, no diffusion of pigment; final H-ion concentration, about pH 6.0 to 5.0 (Conn). Broth: Good growth. Cretaceous layer around edge. Milk: No change at 25° C. (Conn). At 37° C, coagulation. Peptonization begin- ning in 3 to 5 days. Potato : Strong pigment production, some- times greenish blue or violet, but usually sky-blue, diffusing through medium and coloring water at base of tube. Blood agar: Hemolysis showing on 4th day. Miiller reports no acid from carbohydrates on organic media. In synthetic liquid media, acid production from glucose is pronounced; pyruvic and succinic acids have been iden- tified (Cochrane and Dimmick, Jour. Bact., 58, 1949, 723). Nitrites produced from nitrates. Pigment : The most striking characteristic of this organism is a litmus-like pigment, usually produced on potato or synthetic media, which is deep blue and water-soluble at alkaline reactions (beyond pH 8.0), violet around neutrality, and red (insoluble in water) at about pH 6.0. Conn points out that the primary pigment has a spectro- photometric curve almost identical with that of azolitmin but that there are un- doubtedly other pigments produced, es- pecially in the case of the strains believed to be typical of Actinoynyces violaceus -ruber (as previously pointed out by Waksman and Curtis). Aerobic. Good growth at room temperature and at 37° C. Antagonistic properties: Some strains produce coelicolorin and mycetin. Distinctive character: Litmus-like pig- ment. Comments: Because of the numerous colors and shades shown by the pigment ac- cording to final H-ion concentration and other less understood factors, this species may have been described under various names. On the other hand, it is entirely possible, as pointed out by J. E. Conn (op. cit., 1943, 133), that careful study of the pigments may show that more than one species is actually involved. Relationships to other species: Regarded by Waksman and Henrici (in Manual, 6th ed., 1948, 935) as the same as Actinomyces violaceus Waksman and Curtis, Soil Science, 1, 1916, 110 (Actinomyces violaceus -ruber Waksman and Curtis, ibid., 127) and Ac- tinomyces tricolor Wollenweber, Arbeiten d. Forschungsinstitut fiir Kartoffelbau, 1920, 13. It is however, pointed out by Conn {op. cit., 1943, 133) that certain differences be- tween the descriptions of Waksman and Curtis and that of Muller may correspond to actual chemical differences in the pig- ments produced and that the organism of Waksman and Curtis may be a separate species.
