VIII. REPLICATION OF VIRUS PATTERN 103 



ing but the bacterial protoplasm protein which can combine with the 

 phage through structures shared in common between the phage and the 

 bacillus ; the shared structures may be called receptors. 



The protoplasm protein of susceptible cells should have weaker 

 structural effect than the virus in order that the viral pattern is repli- 

 cated in the cells. However, if some of the proteins acquire rigid 

 structure through the combination with certain substances, say with 

 polysaccharides, which make the protein structures rigid, then the pro- 

 teins can act as virus inhibitor having the receptor for the virus. The 

 virus which happens to combine with such rigid structures may be 

 splitted since the virus has to be changed into labile, stretched form on 

 the surface. The above cited claim that all phage particles are broken 

 down upon the adsorption on the host cell suggests that the cell mem- 

 brane may be mostly composed of protein complexes having such rigid 

 structures. Form the point of this view it should be a natural result 

 that the demonstration of the initial infecting virus particles is impos- 

 sible in the cell macerates in which cell components acting as the in- 

 hibitor may be present abundantly. 



Weidel (139 a) has shown in his studies with bacterial membrane 

 preparations that the interaction of intact bacteriophage with the 

 host-cell membranes results in a disintegration of the membranes. 

 This shows that the structure of the membrane was weaker than 

 that of the virus. On the other hand, according to Barrington and 

 Kozloff (139 b), electron micrographs taken at zero time and after in- 

 cubation showed that adsorption of phage was accompanied by the 

 disintegration of the virus and the conversion of the membrane to a 

 granular residue, indicating clearly that at least some of the phage 

 particles combined with the host cell were decomposed together with 

 the cell membrane. In studying the interaction of P^Mabelled phage 

 and host cells, Mackal and Kozloff (139 c) have found that a portion 

 of the virus P was released into the medium in the process. But this 

 release did not occur after adsorption to heat-killed bacteria. This 

 may be attributed to the derangement of the host cell structure by 

 heating resulting in the loss of rigid structure becoming unable to 

 decompose the virus. 



The virus particles may be decomposed on the cell surface into 

 nucleic acids and proteins. The nucleic acids or their constituents thus 

 formed appear to be incorporated into bacterial protoplasm whilst the 

 proteins seem to be never utilized by the host cells. Thus, by infecting 

 E. colt with P^' labeled phage, several workers have demonstrated that 

 30 to 50 per cent of the phage nucleic acid label is incorporated in the 

 resulting "progeny". An equal high per cent to progeny transfer has 

 been reported when the parental nucleic acid contained C^* labeled 



