108 Perspecfives in Microbiology 



as if a potter today made a vase, yesterday a soup bowl, 

 tomorrow a pitcher; the shape varies, the structure alters 

 to serve function more closely, but the same clay has been 

 turned on the same wheel with the same immeasurable 

 skill. 



ConfrJbufions of Microbiology fo Mefabolic Studies 



Microbiology has played a unique and significant role 

 in the acquisition of this knowledge of metabolic pathways 

 and will continue to provide the essential portion of the 

 metabolic information. This fact arises because of two 

 characteristics of microbial metabolism. Because these are 

 sometimes not recognized, we feel it of interest to point 

 them out, since they are, in fact, almost the unique contri- 

 bution of microbiology to the subject of metabolic path- 

 ways. 



The first point is that microorganisms by their very 

 variety provide the necessary tools for such study. Consider- 

 ing an array of organisms that are distinguished by bac- 

 teriological and physiological methods, which is indeed 

 why we know that they are different organisms, metabolic 

 study shows that each is not a separate, unique, metabolic 

 system. Rather, the metabolism of each type of organism is 

 composed, in different proportions, of familiar metabolic 

 pathways; and, of course, of some as yet unknown to us. 

 The relative predominance of each pathway may be altered 

 in a given organism, both by culture conditions and by 

 genetic pattern. There is, among organisms, a certain over- 

 lap, but by the selection of extremes for study one may 

 obtain organisms predominantly of one pathway, as com- 

 pared to others; and thus we may achieve separation of 

 systems, frequently long before their nature is known. 

 Thus it becomes possible to study separate systems and 

 trace predominant metabolic pathways. Additional tech- 

 niques of such selection — simultaneous adaptation and 



