CHAPTER II 

 THE GENERATION OF VIRUSES 



1. Changes in the Structure of Protoplasm Protein 

 Leading to Virus Generation 



Many evidences cited in the previous chapter may indicate that the 

 normal protoplasm particles of certain cells can sometimes exhibit 

 their template action upon certain other cells as viruses. Although 

 the existence of such normal particles never mean the generation of 

 new viruses, it seems highly probable that new viruses can arise in 

 some cells if the protoplasm is altered in its structure following the 

 change of environVnental factors, because the kind of viruses should 

 be determined by the structural pattern of the protoplasm. 



Bacteria sensitive to penicillin usually develop resistance to the 

 antibiotic when grow in its presence. It is of most interest that the 

 extracts of bacteria thus acquired the resistance are able to transmit 

 this character to other bacteria (34). The effective agent prepared 

 from a resistant strain has been reported to be involved in a nucleic 

 acid fraction (35). This can be interpreted as indicating that the bac- 

 terial protoplasm undergoes a change in its structure under the influ- 

 ence of the antibiotic and that, as the newly formed structure is 

 stronger than the original one, some particles of the protoplasm thus 

 changed containing nucleic acid in rich amount can exert like a virus 

 their structural influence upon the unaltered bacteria. This may, there- 

 fore, be regarded as an example of the generation of a new virus due 

 to a certain stimulus given to the cell. 



It is, however, unreasonable to expect that a newly formed 

 structure is always stronger than the original. Voureka (36) has re- 

 corded the interesting observation that some strains of penicillin-re- 

 sistant staphylococci and streptococci lost their resistance during 

 exposure to a penicillin sensitive microorganisms or to the extracts of 

 sensitive bacterial cells. It should be noted that the sensitizing prin- 

 ciple was found in the ribonucleic acid fraction isolated from the 

 sensitive bacteria (37) (38). This fact indicates that the newly for- 

 med structure is weaker than the original and, therefore, the original 

 structure can overcome the newly formed one. The sensitizing princi- 

 ple must be nucleic acid rich particles, behaving like a virus towards 

 the adapted bacteria. 



