Virus differences between bacteriophages

The thermal inactivation of the bacteriophages, like the denatura-tion of most proteins, is a first order reaction characterized by a great dependence on the temperature and the salt composition of the solution (2,6,235). Adams (2) and Foster et al. (109) have investigated the effect of salts on the stability, and Pollard and co-workers (6,236) have compared thermal inactivation in the wet and the dry states. Adams found that the 7 T viruses are inactivated much more rapidly in 0.1 A solutions of sodium salts than in broth or in dilute solutions of divalent cations. The difference in stability was most marked for T5. Although T5 is inactivated 10 times more rapidly in 0.1 N NaCl than in broth, the optimal stability, indistinguishable from that in broth was attained at 6 X 10 M Ca++ or Mg++ and at 2 M NaCl. The increase in stability of T5 in the presence of various cations was assumed to occur as the result of complex formation between the virus and the metal ion. 

When N -labeled E. coli are infected with T6r+ bacteriophage, about 80% of the viral N is derived from the medium and the other 20% comes from the bacterial cell (Kozloff, Knowlton, Putnam, and Evans, 160,163) the converse holds true when E. coli are infected with T7 (Putnam, Miller, Palm, and Evans, 262). Thus, the assimilation of virus N resembles that for virus P in that relatively more of the inorganic compounds of the medium are channeled into virus synthesis for the large phages than for the small ones. However, several important differences exist between N and P metabolism during phage multiplication (1) Analytically, P occurs almost wholly in the virus nucleic acid, whereas N is about equally divided between the nucleic acid and protein of the phage. Tracer... 

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