224 THE ANTIBIOTICS 



by the mycelium of S. phoenix in absence of excess oxygen. Organic 

 solvent solutions and dry powders are stable indefinitely at 55°C. 



Biological activity: Active against mycobacteria, gram-positive, and gram- 

 negative bacteria. It is active in vivo in mice against Streptococcus 

 pyogenes. It is much more active by the intraperitoneal route than by 

 the intravenous or intramuscular routes. 



Toxicity: LD 50 (mice), intraperitoneal, 2.1 mg/kg; intravenous, 2 mg/kg; 

 intramuscular, 3 mg/kg. 



Utilization: Probably none. 



Reference: Charney, J., Machlowitz, R. A., Roberts, W. S., and Fisher, 

 W. P., Antibiotics & Chemotherapy, S, 1953, 788-792. 



Rhodomycetin 



Produced by: Red mutant of Streptomyces griseus. 



Method of extraction: Precipitation with acid and extraction of precipitate 

 with methanol; also extraction of broth with n-butanol. 



Chemical and physical properties: Red in acid solutions and blue at alkaline 

 reactions. Unstable under alkaline conditions. Can stand 10 minutes 

 at 70°C at pH 7.0. Insoluble in water; soluble in ethylene glycol 

 monomethyl ether, ether, acetone, acetic acid, and various alcohols. 

 Maximum light absorption at 235, 540, and 580 mju. 



Biological activity: Active against gram-positive bacteria, moderately active 

 against mycobacteria, almost no activity against gram-negative bac- 

 teria. No activity in mice. 



Toxicity: No clear data available. 



Reference: Shockman, G., and Waksman, S. A., Antibiotics & Chemo- 

 therapy, 1, 1951, 68-75. 



Rhodomycin 



Produced by: Streptomyces sp. 



Method of extraction: From aqueous solutions of both broth and mycelium 

 at pH 8.6 with butanol, chloroform, or ether. 



Chemical and physical properties: Amphoteric dark red pigment acting as a 

 pH indicator. As the chloride or phosphate, it is water-soluble. As a 

 picrate, it is water-insoluble. Soluble in organic solvents. Maximum 

 light absorption in benzene at 575, 542, 533, and 504 m/x. Unstable at 

 acid and alkaline pH. C22H29NO7. Through mild acid hydrolysis, rho- 

 domycin can be split into a basic, nonpigmented, water-soluble sub- 

 stance and a water-insoluble pigment. The pigment is an oxynaph- 

 thoquinone (CibHi 4 6 ). 



Biological activity: Rhodomycin stops growth of Micrococcus pyogenes var. 



