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VIRUS-INDUCED ACQUISITION 

 OF METABOLIC FUNCTION* 



Seymour S, Cohen 



UNIVERSITY OF PENNSYLVANIA 



The detailed chemical study of the course of bacterial virus multipli- 

 cation has been in progress slightly less than 15 years, antedating the 

 chemical study of the multiplication of animal and plant viruses by 

 about a decade. This pioneering role for the bacteriophage systems 

 stems from their exceptionally favorable atti'ibutes in such matters as 

 ease of cultivation and assay of host and virus, establishment of the 

 time and multiplicity of infection, etc. Of some historical interest is 

 the fact that the bacterial viruses subjected to the most detailed chemi- 

 cal exploration {i.e., the T-even phages T2, T4, and T6) are biochemi- 

 cal freaks. The unique properties of these phages have contributed to 

 their extreme virulence, which in itself has facilitated the study of 

 these viruses. 



In my laboratory our problems were posed initially in the some- 

 what trivial terms of the molecular mechanism of the extremely viru- 

 lent activity of the T-even phages of EscJierichia coli. Many other 

 laboratories have developed their problems in the more general terms 

 of the molecular bases of inheritance for these same phages. In the 

 last three years, the problems of virulence in these systems have been 

 more or less solved in terms of the discovery of a series of rapid syn- 

 theses of many enzymes and proteins controlled by the insertion of viral 

 DNA into the infected bacterium. Thus the problems of the virulence 

 of these phages can now be posed in the terms and problems of molec- 

 ular genetics. Our progress in this area has now catapulted us into 

 the same pot of molecular biology in which almost everyone else is 

 stewing. In this paper we shall summarize the unifying studies of the 



" The work performed in the author's laboratory has been aided greathj by 

 grants from the Commonwealth Fund and the Upjohn Company. 



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