CHEMICAL INTERFERENCE WITH PHAGE GROWTH 285 



terial multiplication. The yield of phage may be decreased in 

 the manner mentioned, particularly of gram-positive bacteria 

 (Krueger, Cohn, Smith, and McGuire, 1948; Elford, 1948; 

 Himmelweit, 1945; Nicolle and Faguet, 1947). The acceler- 

 ated lysis in the presence of penicillin may well be a manifesta- 

 tion of inhibited synthesis of cell wall material. 



In most cases, the inhibition of phage production by strepto- 

 mycin or dihydrostreptomycin parallels bacterial inhibition. 

 However, differential inhibition of phage was demonstrated by 

 Edlinger (1949) and by Bourke, Robbins, and Smith (1952). 

 In both cases the action could not be explained by the previously 

 reported ability of streptomycin to inactivate free phage particles 

 (Cohen, 1947b; Jones, 1945). 



Aureomycin affects the production of T3 (Altenbern, 1953) 

 as well as that of other coliphages (Masry, 1953). In all cases, 

 aureomycin decreases the rate of adsorption, prolongs the latent 

 period, and reduces the burst size by at least one half. 



A number of antibiotics with specific antiphage properties, 

 primarily phagicidal, have been described by Asheshov and his 

 associates. The notable members of this series include phagoles- 

 sin A58 (Hall and Asheshov, 1953) and chrysomycin (Strelitz, 

 Flon, and Asheshov, 1955). 



b. Aroma lie Dia mi dines 



The aromatic diamidines, which include propamidine, pent- 

 amidine, and stilbamidine, were introduced into the chemo- 

 therapeutic arena as trypanosomacidal agents. Their action in 

 phage-bacterial systems shows two opposite effects. Pentami- 

 dine permits growth of Tl, and even increased production, 

 under conditions which are completely bacteriostatic for the un- 

 infected bacteria (Boyd and Bradley, 1951; Amos and Voll- 

 mayer, 1957). On the other hand, propamidine and stilb- 

 amidine, but not pentamidine, prevent the production of other 

 phages (Hotchin, 1951; Bourke, Robbins, and Smith, 1952; 

 Bird, 1956). These findings have particular significance in 

 view of the often recorded similarities between the actions of the 



