CHAPTER XV 



CHEMICAL INTERFERENCE WITH 

 PHAGE GROWTH* 



The effects of chemical agents on phage growth have been 

 touched on in previous chapters, particularly when specific 

 requirements for the various stages of phage development were 

 considered. This chapter will serve to integrate and consider in 

 more detail the varieties of chemical interference which may be 

 imposed upon the phage-reproducing system. In terms of over- 

 all consequences such interference is a form of chemotherapy if 

 we extend the definition of chemotherapy to include chemo- 

 piophylaxis of cyclic or subsequent infection. The inhibitors 

 which prevent the growth of phage do not, as a rule, cure the 

 afflicted bacterial host of its phage infection. The inhibitors 

 either prevent the bacteria from becoming infected or they halt 

 the formation of new phage progeny; the infected cells are 

 sacrificed. Therapeutic action can be considered only in terms 

 of freeing a bacterial community of an infectious agent so that 

 the healthy members are spared and the population flourishes. 

 As in all cases of effective chemotherapy, this implies properties 

 of selective toxicity in that one member of the host-parasite com- 

 plex is destroyed without affecting the other. Though this may 

 be a desirable circumstance in our development and under- 

 standing of viral chemotherapy, it need not be the sole pre- 

 requisite for consideration. Indeed, investigations with chem- 

 ical agents which exhibit no selective action in the phage- 

 bacterium system have helped considerably in determining how 

 much of the bacterial metabolism is required to support the 

 growth of phage. Further details covering problems of virus 



* Chapter contributed by Joseph S. Gots. 

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