REQUIREMENTS FOR PHAGE PRODUCTION 245 



activity of the infected cells remains unimpaired (Hartman, 

 Mudd, Hillier, and Beutner, 1953). Synthesis of at least one 

 enzyme is abruptly terminated (Benzer, 1953), but protein 

 synthesis as a whole continues unabated (Cohen, 1949; Hershey, 

 Garen, Fraser, and Hudis, 1954). 



Cohen (1947a) summed up these metabolic effects as follows: 

 "The virus appears to be synthesized by the cell according to the 

 models (templates) which it provides for the host's enzymes." 

 Luria (1950) refers to "parasitism at the genetic level." Both 

 authors express what is now the common view: after infection 

 with T2 specific bacterial functions, such as synthesis of bacterial 

 DNA and bacterial enzymes, can be dispensed with. General- 

 ized processes, such as formation of amino acids and nucleotides, 

 and doubtless oxidative phosphorylation, remain essential to 

 viral growth. The bacterium, as we have seen, must furnish 

 these generalized working systems out of its past activity; the 

 phage cannot create them and indeed renders the bacterium un- 

 fit to do so ; it supplies mainly a new detailed plan for coordinated 

 action of existing metabolic systems. The following observations 

 are consistent with this view in showing that deliberate inter- 

 ference with specific bacterial syntheses does not prevent growth 

 of phage. 



Bacteria treated with as many as 30 lethal doses of ultraviolet 

 light are still able to support the multiplication of phage T2 

 (T. F. Anderson, 1944, 1948d; Luria and Latarjet, 1947; La- 

 baw, Mosley, and Wyckoff, 1950a, b). Jacob, Torriani, and 

 Monod (1951) exposed E. coli to sufficient ultraviolet light to re- 

 duce the survivors by a factor of 1 0\ As a result of this treatment 

 the bacteria lost ability to synthesize the inducible enzyme j8- 

 galactosidase in detectable amounts, yet still were able to produce 

 T2. Phage can also multiply in bacteria treated with many 

 lethal doses of X-rays, as demonstrated by Rouyer and Latarjet 

 (1946), by Latarjet (1948), and by Labaw, Mosley, and WyckofT 

 (1953). Similarly, bacteria rendered nonviable by treatment 

 with mustard gas are able to support growth of phage T2 

 (Herriott, 1951b). Irradiation and mustard treatment probably 



