464 ROLLIN D. HOTCHKISS 



the surface and probably plays no role after infection is established. What- 

 ever happens after this appears to be determined by the DNA portion. 



c. Genetic Aspects of Phage Reproduction 



In the subsequent stages of T phage reproduction, quantities of phage 

 protein membranes and phage DNA are synthesized in the infected cell. 

 These are specific macromolecular materials different from any of the com- 

 ponents of the uninfected host. It is generally assumed that such species- 

 specific materials are produced under the influence of specific genetic de- 

 terminants (even when these have not yet been recognized in mutant forms 

 suitable for direct genetic experimentation). Accordingly, the biochemical 

 processes leading to the production of these constituents were presumably 

 initiated through the genetic action of that part of phage which is trans- 

 ferred to and retained by the infected host — the significant part identified 

 from its phosphorus content as DNA. 



The text of Fig. 2 gives a summary of the chemical processes observed 

 during infection of E. coli with T phages. A few of the findings given there 

 have only been observed with T2 (or Te) phage — it is likely that all are 

 essentially true for the "T-even" (2, 4, and 6) phages and their various 

 mutants and, so far as is known, probably for the other T phages as well. 

 References not otherwise covered include those to: chemical analyses of 

 host cells'^" and of phage i"^'!^''-'®^ study of infected cells as to changes of 

 cell organization,'^^ metabolism, ^®^-^*'^ or protein synthesis;'^" ''^degradation 

 and utilization of input phage;'^^'"'^*'^'"" recognition of synthesized 

 phage,"' its DNA, '^^'^2 its protein,'^^'^^ or the origin of its components.'*^- 



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" L. M. Kozloff, J. Biol. Chem. 194, 95 (1952). 



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