4 Perspectives in Microbiology 



mental aspects of life. Occasionally they could reiterate 

 their hope that some day the neglected opportunities would 

 attract others to the larger field; meanwhile they continued 

 their work, assured by a long-range point of view and by 

 the fascination of the subject itself. 



But during the last fifteen years a marked change has 

 taken place. The number of publications concerned with 

 microorganisms from other than medical points of view 

 has increased enormously, and several new journals have 

 been started to accommodate the swollen current of reports 

 dealing with biochemical studies in which microbes have 

 played a part. One of the chief reasons for this develop- 

 ment has been the influence exerted by A. J. Kluyver's 

 masterly synthesis of the information on the vast diversity 

 of metabolic processes carried out by the numerous types 

 of microorganisms. This synthesis revealed that all bio- 

 chemical events can be interpreted as composites of more 

 or less extended series of step reactions, each step chemi- 

 cally intelligible and representing a special case of simple 

 electron transfer between two different molecules, medi- 

 ated by a specific enzyme. Depending upon the nature of 

 the participating reactants, this leads to the transfer of 

 atoms or larger units from one molecule to another, as in 

 transhydrogenations, transphosphorylations, transamina- 

 tions, transmethylations, transacetylations, and transglu- 

 cosidations. 



While emphasizing the fundamental unity in the bio- 

 chemical behavior of all living beings, Kluyver's contribu- 

 tions also drew attention to the existence among micro- 

 organisms of extreme cases of biochemical specialization 

 and of processes that may be characterized as grossly 

 exaggerated examples of phenomena that are encountered 

 elsewhere as quantitatively minor side reactions. That 

 organisms which display such properties are signifi- 

 cant for more detailed investigations on the particular 

 reaction mechanisms involved was clearly appreciated. 



