208 THE ANTIBIOTICS 



Biological properties: Active primarily against gram-positive bacteria, 

 limited activity against gram-negative bacteria and mycobacteria. 

 Strains of Staphylococci, Vibrio comma and one Mycobacterium were 

 the most sensitive organisms (1-2 mcg/ml). 



Toxicity: LD 60 (mice), intraperitoneal, more than 250 mg/kg. 



Utilization: Unknown. 



Reference: Waga, Y., J. Antibiotics (Japan), A 6, 1953, 66-72. 



Griseolutein 



Produced by: Streptomyces griseoluteus. 



Method of extraction: Extraction at pH 2.0 with ethyl acetate. Ethyl ace- 

 tate concentrate chromatographed over alumina. Yellow fractions con- 

 tain the antibiotic which crystallizes at 0°C. 



Chemical and physical properties: Yellow needle-shaped crystals. C = 59.5 

 per cent; H = 4.4 per cent; N = 8.0 per cent. Insoluble in water and 

 ether, slightly soluble in ethyl acetate and alcohol. Soluble but un- 

 stable at alkaline pH. Maximum stability at acid reaction. 



Biological activity: Active against gram-positive and gram-negative bacteria. 



Toxicity: No toxicity to mice injected subcutaneously at 1000 mg/kg. 



Utilization: Unknown. 



Reference: Umezawa, H., Hayano, S., Maeda, K., Ogata, Y., and Okami, 

 Y., J. Antibiotics (Japan), 4, 1951, 34-40. 



Helixin 



Produced by: Streptomyces sp. 



Synonym: Closely related to endomycin. 



Method of extraction: Precipitation at pH 3.0, extraction of the precipitate 



with ethanol. 

 Chemical and physical properties: Soluble in ethanol, methanol, pyridine, 



glacial acetic acid; slightly soluble in n-butanol, acetone, chloroform; 



insoluble in ether, petroleum ether, benzene, ethyl acetate, and car- 

 bon tetrachloride. Most active at alkaline pH. Somewhat less stable 



than endomycin. 

 Biological activity: Active against filamentous and nonfilamentous fungi 



in concentration of 15 meg or less per ml. Active against bacteria in 



concentrations of 30 meg or more per ml. 

 Toxicity: Inhibition of seed germination by 25 to 100 mcg/ml. Toxic to 



tomato cuttings in concentration of 7.5-15 mcg/ml. 

 Utilization: No data. 

 Reference: Leben, C, Stessel, G. J., and Keitt, G. W., Mycologia, 44, 1952, 



159-169; Leben, C., and Keitt, G. W., Phytopathology, 4%, 1952, 



168-170. 



