INTRACELLULAR BACTERIOPHAGE FORMATION 



7i 



resistant. This probably indicates a second mechanism of phage for- 

 mation. At the present time there is not enough evidence to support 

 the view that there are two distinct mechanisms of phage formation 



Capacity 



N,/No(22) 



4 8 12 24 48x10 



Dose(r) 



96x10' 



Fig. 1. — Effect of X-rays on the capacity of E. coli B to form phage T 3. 



O Survival of the bacteria 



O Change in capacity immediately after irradiation. 

 # Change in capacity 24 hr after irradiation. 

 Numbers in brackets : age of the culture in hours. 



with differing radio -resistance. However, several examples do exist 

 where dose-effect curves are non-uniform, indicating processes with 

 different radio-resistances. 



Another possible explanation based on the non-homogeneity of the 

 particular population of E. coli B resulting in two different types of 

 capacity appears to be even less probable. The reason is that in such a 

 case the inactivation curve of the colony-forming ability should be also 

 biphasic, and this is not the case. 



In lookuig for an explanation of the biphasic nature of the bacterial 

 capacity, we tried to influence the phage production of the irradiated 

 bacterial cells by chloramphenicol. It is known that chloramphenicol 

 inhibits protein synthesis in £". coli B (Wisseman et al., 1954). In E. coli B 

 cells irradiated with X-rays or u.v.. Gillies and Alper (1959) found a 

 higher survival rate in cells incubated on agar containing chloram- 

 phenicol. Phage formation by bacterial cells is also influenced by 

 chloramphenicol (Bozeman e^ aL, 1954; Crawford, 1957, 1959). It was. 



