MICROBIAL METABOLISM AND ITS INDUSTRIAL IMPLICATIONS 



nature; each one is tested for its antagonistic properties and if these 

 are satisfactory, the optimal conditions for production of the antag- 

 onistic principle will have been determined. At this stage the bio- 

 chemist may take over the job of devising suitable methods for the 

 isolation of the active principle, and if successful will attempt to estab- 

 lish its chemical nature. Then the pharmacologist will have to make 

 the necessary animal experiments in order to decide on the degree of 

 toxicity. If his reports are also favourable, production on a somewhat 

 larger scale will be necessary to provide the material needed for a 

 thorough clinical test. And in the quite exceptional case that the new 

 antibiotic passes all these stages, a new branch of microbiological 

 industry may develop. 



How should we judge the prospects for a further development of the 

 antibiotic industry? It seems that a bright future still lies ahead. For 

 a documentation of this statement it is instructive to glance at the 

 chemical formulae of the three established antibiotics of which the 

 chemical constitution has been elucidated, to wit: penicillin, strepto- 

 mycin and chloramphenicol (Table XIII). 



Here we have three molecules which were all quite new to science 

 when their configurations were determined. Before their discovery, 

 even the boldest organic chemist would hardly have considered their 

 synthesis. If he had, nothing but a miracle could have induced him 

 to test the therapeutic value of his preparations, none of the structures 

 suggesting anything of their beneficial specific action. 



It is true that each molecule considered separately has its remark- 

 able features. For penicillin, both the thiazolidine ring and the beta- 

 lactam ring are characteristic and - as far as I know - the latter has 

 never before been encountered in naturally occurring compounds. 



As for the formula of streptomycin, it can most aptly be described 

 as the product of an organic chemist just before his admittance to a 

 lunatic asylum. The structures of each of the three moieties of the 

 molecule are equally irrational and the mere idea that nature has 

 thought fit to combine these elements to form a molecule with remark- 

 ably specific action tends to depress the most modest amongst biol- 

 ogists. 



Finally, there remains the miracle of chloramphenicol. It is true 

 that its structure is much more simple, so much so that it has fallen a 

 relatively easy prey to the organic chemist. But here we encounter two 



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