INVESTIGATIONS ON A LYSOGENIC BACILLUS MEGATERIUM 



important process of multiplication involving the death of the bacterium. In 

 contrast, after the penetration of the bacteriophage into a resistant bacterium 

 destined to become lysogenic the probacteriophage behaves as a nonpathogenic, 

 normal cellular unit, which does not assume a pathological development except 

 as a consequence of an "activation." This development in a bacterium of a 

 particle which ultimately becomes "malignant" recalls in some respect the 

 multiplication of neoplastic cells in a cancerous organism. 



One could be tempted to write, as perhaps we ourselves have done, that 

 potentially lysogenic bacteria live "in equilibrium" with their bacteriophage. 

 But, in fact, they live in equilibrium with a probacteriophage. There exists an 

 incompatibility between the structure "bacteriophage-virus" and the survival 

 of the bacterium. 



It is true that lysogenic bacteria are resistant to the bacteriophages which 

 their sisters produce. But no more than a sensitive bacterium does a lysogenic 

 bacterium resist the multiplication of bacteriophages. It is thus the multiplica- 

 tion of bacteriophages which constitute the pathologic fact. 



IX. Resume and Conclusions 



1. Bacillus megaterium cells washed and isolated in microdrops were utilized 

 in an attempt to resolve some of the problems posed by lysogenic bacteria. 



2. B. megaterium can multiply without liberating bacteriophage: production 

 of bacteriophages thus does not obligatorily accompany the growth and the 

 division of the bacteria. 



3. The capacity to produce bacteriophages was maintained in the course of 

 19 divisions in the absence of all free bacteriophages: the faculty to produce 

 bacteriophages is thus perpetuated intrabacterially. 



4. Rapid lysis of lysogenic bacteria was observed under the microscope. This 

 lysis is followed, and never preceded, by liberation of bacteriophages. B. 

 megaterium thus liberates bacteriophages by lysis. 



5. The proportion of bacteria which liberate bacteriophages varies within 

 considerable proportions: from less than 5% to 30%. All indications are that the 

 production of bacteriophages is induced by external factors. 



6. Lysogenic bacteria are defined as bacteria in which the capacity to produce 

 bacteriophages is perpetuated without intervention of exogenous bacteriophages. 



7. The theory of the activation of an intracellular anlage of the bacteriophage 

 (F. Burnet and M. McKie) has been discussed, developed, and amended. 



BIBLIOGRAPHY 



Adams (M. H.). /. Immunol., 1949, 62, 505-516. 



Bayne-Jones (S.) et Sandholzer (L. A.). /. exp. Med., 1933, 57, 279-304. 



BoRDET (J.). Ces Annales, 1925a, 39, 717; C. R. Soc. Biol. Beige, 19256, 93, 1054. 



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