Chapter 



2 



Some Aspects of 

 Metapoietic Integrations 



By ANDRE LWOFF 



Microbes are able to undergo a variety of 

 inheritable changes: gene mutations, loss of plasmagenes 

 endowed with genetic continuity, transformations, or trans- 

 ductions. As a result, the microbe is temporarily or perma- 

 nently modified. It has lost or acquired the ability to syn- 

 thesize or to metabolize one or many substances. And in 

 some cases the change has been shown to be related to the 

 loss or the acquisition of the power to synthesize a specific 

 enzyme. 



These variations may be considered as consequences of 

 the modification of "normal" metabolism. In some cases, 

 however, a hereditary pathological property may be im- 

 posed on the microbe; namely, the power to produce bac- 

 teriophage or lysogeny. 



As is well known, a lysogenic bacterium is endowed with 

 the hereditary power to produce bacteriophage. This prop- 

 erty is bound to the presence of a specific particle: the 

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