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THE ACTINOMYCETES, Vol. I 



lilt ion; they are changed, on treatment with 

 concentrated H2SO4 , first to green, then to 

 dark brown. The yellow-red pigment of N. 

 corallina wa.s identified as belonging to the 

 lipochrome group of fat-soluble pigments. 



Nature of the Pigments 



Anthocijanins 



These pigments are readily soluble in wa- 

 ter and in aqueous glycerol, alcohol, and 

 other water-containing solvents. They are 

 insoluble in absolute alcohol, chloroform, 

 and other organic solvents. They are red in 

 dilute acid solutions and blue in alkaline so- 

 lutions. The neutral point is about pH 7.5. 



The blue pigment of S. coclicolor has been 

 extracted with cold and hot water as well as 

 with alcohol. This pigment became red w^hen 

 treated with acid, and green when treated 

 with 25 per cent alkali solution. Addition of 

 lead acetate to the aqueous solution of the 

 pigment brought about the formation of a 

 violet precipitate. Miiller (1908) first sug- 

 gested the similarity of this pigment with 

 anthocyanin. Kriss confirmed these results 

 fully. Krassilnikov also confirmed the results 

 and emphasized that the anthocyanins or 

 allied pigments are characteristic of several 

 actinomycetes. He pointed out that all the 

 blue pigment-producing actinomycetes be- 

 long to S. coclicolor Miiller. The cultures all 

 produce a blue pigment which diffuses into 

 the medium, conferring upon the medium 

 the corresponding color. If the reaction of 

 the medium changes to acid as a result of 

 the growth of the organism, the color of the 

 culture becomes I'ed; on alkalinization of the 

 medium, the color again tuins blue. 



According to Waksman, the pigment pro- 

 duced by S. violaceoruhcr behaves as an indi- 

 cator, being red in an acid medium and blue 

 in an alkaline medium; the change in pig- 

 mentation takes ])Ia('e a( pH G.C). According 

 to Frampton and Taylor (19o<S), the pig- 

 ment produced l)y S. violaccoi uhcr is an 



anthocyanin; it was isolated as the crystal- 

 line picrate. These workers considered the 

 pigment as a rhamnose glucoside, the carbo- 

 hydi-ate groups being rhamnose and glucose. 

 The sugars were believed to be separately 

 attached to the anthocyanidin residue. 



Jean Conn concluded that the two blue 

 pigments produced by *S. coclicolor and ;S. 

 violaceoruhcr are not identical; the first is 

 similar but not identical to azolitmin. On the 

 basis of this differentiation, she believed that 

 the two organisms represent distinct species. 

 Oxford and Erikson ct al., however, could 

 not accept the phenazine or anthocyanin 

 nature of these pigments. 



Tonolo et al. (1954) described the isolation, 

 from a culture related to »S. coclicolor, of a 

 pigment designated as streptocyanin. The 

 course of pigment production in a glycerol 

 medium is shown in Figure 79. The pigment 

 was soluble in acetone, pyridine, and diox- 

 ane. It colored blue-violet with H2SO4 and 

 decomposed at 290 to 300C°. It gave a band 

 in the visible spectrum. A quinoid structure 

 was postulated for the pigment. It showed 

 antibiotic activity. 



Green Pigments 



Actinomycetes were found to produce sol- 

 uble green pigments, which is the reason for 

 such species names as S. viridis, S. virido- 

 cliromogenes, and S. vernc. Some of these 

 pigments are soluble in glycerol and in al- 

 kaline solution, but not in organic soh'ents. 

 The color of the pigment in water is green; 

 in glycerol, yellowish green. The composition 

 of the medium influences the nature of this 

 pigment. Green pigments produced by ac- 

 tinomycetes were also reported by other in- 

 \'estigators. 



One of the most interesting of the green 

 pigments was recently studied by Chain and 

 Tonolo. They isolated a culture of a strepto- 

 myces that produc(^d on yeast agar an in- 

 tense green nondiffusible pigment. This pig- 

 nuMit was also formed in submerged. 



