126 ACTINOMYCETES AS ANTAGONISTS 



designated as proactinomycin (313). Its bacteriostatic spectrum is 

 shown in Table 23. It is produced on both synthetic and organic media. 

 It is effective chiefly against gram-positive bacteria, although to a more 

 limited extent than actinomycin. 



S. violaceus produces on synthetic media a substance partly soluble 

 in water, and largely soluble in alcohol, benzene, chloroform, and di- 

 chlorethane, but not in ether. It gives a deep violet color in alcoholic 

 solution and is active against gram-positive bacteria, less so against 

 mycobacteria and corynebacteria, and not at all against gram-negative 

 bacteria. It was designated as mycetin (245, 533a). Various gram-nega- 

 tive bacteria, as well as pus, reduce its activity. 



A^. cyanea (Pr. cyaneus) produces a pigment, designated litmocidin, 

 which is related to the anthocyanins and inhibits the growth of various 

 bacteria in vitro but not in vivo (8oa, 323b). 



TABLE 23. BACTERIOSTATIC EFFECT OF PROACTINOMYCIN 



APPROXIMATE DILUTION OF 

 MATERIAL IN MILLILITERS 

 ORGANISM GIVING HIGHEST EFFECT 



D. fneumoniae 1,500,000 



S. fyogenes 500,000 



S. aureus 500,000 



A'', meningitidis 500,000 



B. anthracis 500,000 



V . comma 6,000 



.y. tyfhi, S. faratyfhi B, Shigella, E. coli 2,000 



From Gardner and Chain (313). 



S. alhus forms a bacteriolytic substance designated as actinomycetin, 

 which is a protein and is enzymatic in nature. Its lytic action upon bac- 

 teria was visualized by Welsch (looo) as a two-step reaction: first, 

 the susceptible cells are killed by the selectively bactericidal lipoid j sec- 

 ond, those dead cells are dissolved by the bacteriolytic enzyme, which 

 alone is responsible for the lysis of heat-killed bacteria. The phenome- 

 non does not take place in complex culture media, since the bactericidal 



