50 



VIRAL PROTEIN AND NUCLEIC ACID IN BACTERIOPHAGE GROWTH 



The distribution of S*^ and phage among fractions obtained from three cul- 

 tures of this kind is shown in Table VI. The results are typical (except for the 

 excessively good recoveries of phage and S^^) of lysates in broth as well as 

 lysates in glycerol-lactate medium. 



The striking result of this experiment is that the distribution of S^^ among 

 the fractions is the same for early lysates that do not contain phage progeny, 

 and later ones that do. This suggests that little or no S^* is contained in the 

 mature phage progeny. Further fractionation by adsorption to bacteria con- 

 firms this suggestion. 



Adsorption mixtures prepared for this purpose contained about 5 X 10* 

 heat-killed bacteria (70°C. for 10 minutes) from 18 hour broth cultures, and 



TABLE VI 



Per Cent Distributions of Phage and 5'^ among Centrifugally Separated Fractions of Lysates 

 after Infection with S^^-Labeled T2 



Infection with S'*-labeled T2, 0.8 particles per bacterium. Lysing phage UV-killed h 

 mutant of T2. Phage yields per infected bacterium: <0.1 after lysis at / = 0; 0.12 at / = 

 10; maximal yield 29. Recovery of S'^ means per cent of adsorbed input recovered in the 

 four fractions; recovery of phage means per cent of total phage 3'ield (by plaque count before 

 fractionation) recovered by titration of fractions. 



about 10'' phage (UV-killed lysing phage plus test phage), per ml. of adsorp- 

 tion medium. After warming to 37°C. for 5 minutes, the mixtures were diluted 

 with 2 volumes of water, and centrifuged. Assays were made from supernatants 

 and from unwashed resuspended sediments. 



The results of tests of adsorption of S^'^ and phage to bacteria (H) adsorbing 

 both T2 progeny and //-mutant lysing phage, to bacteria (B/2) adsorbing lysing 

 phage only, and to bacteria (B/2//) adsorbing neither, are shown in Table VII, 

 together wdth parallel tests of authentic S^^-labeled phage. 



The adsorption tests show that the S^^ present in the seed phage is adsorbed 

 with the specificity of the phage, but that S^^ present in lysates of bacteria 

 infected with this phage shows a more complicated behavior. It is strongly 

 adsorbed to bacteria adsorbing both progeny and lysing phage. It is weakly 

 adsorbed to bacteria adsorbing neither. It is moderately well adsorbed to bac- 



98 



