Mefapoiefic Integrations 23 



Obviously, the properties of lysogenic systems which are 

 bound to the prophage are the result of interaction of 

 the genetic material of the phage and of the bacterium. 

 Many hypotheses can be considered to account for the 

 alterations of the bacterial metabolism that are the result 

 of lysogenization. It could be that the prophage modifies 

 the bacterial genes adjacent to the locus of attachment. 

 It could also be that some of the prophage genes actively 

 intervene in a specific process, such as the synthesis of a 

 protein or of a part of a protein. We are unfortunately, for 

 the time being, left with hypotheses. Whatever the solu- 

 tion — or solutions — of the problem may be, it is possible 

 to conclude that the genetic material of the bacteriophage, 

 when attached as prophage to a bacterial chromosome, is 

 not solely a potential bacteriophage. The prophage takes 

 part in the daily life of the bacterium as if it were a cog 

 in the bacterial machinery. It plays its part in the molecular 

 orchestra. 



Thus, the structural basis of a viral disease and the bac- 

 terium may be integrated. Some of these integrations have 

 been recognized as metapoietic. 



It is certain that many more examples of such integra- 

 tion will be brought to light. The mechanism of the 

 phenomenon will have to be disclosed. 



References 



1. Benzer, S. Personal communication. 



2. Bertani, G. Infections bacteriophagiques secondaires des bacteries 

 lysogenes. Ann. Inst. Pasteur, 84:273-280, 1953. 



3. Freeman, V. J. Studies on the virulence of bacteriophage-infected 

 strains of Corynebacterium diphtheriae. J. Bact., 61:675-688, 1951. 



4. Groman, N. B. /. Bact. (in press). 



5. lonesco, Helene. Sur une propriete de Bacillus megaterium \i6e 

 a la presence d'un prophage. Compt. rend., 237:1794-1795, 1953. 



6. lonesco, Helene. Syst^mes inductibles et non inductibles chez 

 Bacillus megaterium lysogene. Compt. rend., 233:1702-1704, 

 1951. 



7. Lederberg, Seymour. Personal communication. 



