368 



METABOLISM OF MICROORGANISMS 



biologically and chemically. The structural formula for terramycin was 

 worked out first and is given above. Aureomycin, CooHosNoOsCl, has 

 the same basic structure as terramycin. Both are derivatives of naphtha- 

 cene and have many groups in common. Aureomycin contains a chlorine 

 atom and one less hydroxyl group than terramycin, but the chlorine and 

 hydroxyl group are not interchangeable. They occupy different places 

 in the molecule, as indicated by the CI and H in parentheses in the struc- 

 tural formula. Chlorine replaces a hydrogen at position 10, and a hydro- 

 gen takes the place of the hydroxyl at 12 in the terramycin formula. 

 There seems also to be some doubt as to the location of the dimethylamino 

 group in aureomycin; it may be interchanged with the hydroxyl group 

 attached at 4a. Both compounds form yellow-colored salts and have 

 many other similar physical and chemical properties. For further details 

 the many papers on these antibiotics that have appeared recently should 

 be consulted. 



As would be expected from their close chemical relationship, they 

 are much alike in their bacterial spectrum. Both act on gram-positive ^ 

 and gram-negative bacteria, on organisms producing rickettsial diseases, 

 e.g., typhus fever, and are potent in certain virus infections, such as 

 virus pneumonia. Neither antibiotic is effective against the tubercle 

 bacillus, bacteria of the proteus and pseudomonas types, or fungi. Aureo- 

 mycin and terramycin are given by mouth in clinical treatments. 



Aureomycin and terramycin are produced commercially by fermenta- 

 tion. The microorganism producing aureomycin is called Streptomyces 

 aureofaciens because of the golden yellow appearance of the colonies of 

 the microorganism on agar plates and also because the antibiotic is yellow. 

 The terramycin organism is named Streptomyces rimosus because of the 

 cracked appearance of the colonies on agar plates. 



Since each antibiotic is produced by a single company, no official 

 figures are available as to the yearly production. Judging from the 

 widespread use of these antibiotics, their production must be several 

 hundred thousand pounds per year and their market value must run 

 into millions of dollars. 



Chloromycetin (Chloram,phenicol). Chloromycetin is the name com- 



H H 



C=C H HN-CO-CHCU 



O.N-C C-C C-CH,OH 



\ / I I 



C— C OH H 



I I 

 H H 



Chloromycetin 



^ Bacteria that take the gram-stain are called gram-positive and those that do not 

 are said to be gram-negative. Consult a book on bacteriology for the reagents {e.g., 

 gentian violet, etc.) used in making the stain and the method of performing it. 



