154 A. N. BELOZERSKY AND A. S. SPIRIN 



However, by exposing cells to the action of some reagents, e.g., chloram- 

 phenicol, 51 ' 53, 60 one succeeds in separating the syntheses of protein and 

 RNA, so that RNA synthesis will proceed in the cells, whereas protein syn- 

 thesis will be completely inhibited. Another group of data, for example, on 

 the effect of penicillin, 21 ' B1, 53, 61 shows a complete correlation of the inhibi- 

 tion of RNA and protein synthesis. Gale 51 pointed out that no antibiotic 

 was found which would inhibit RNA synthesis without a corresponding 

 slowing down of protein synthesis. It is possible, apparently, to inhibit 

 protein synthesis without inhibiting that of RNA, but the inhibition of 

 RNA synthesis inevitably brings about the suppression of protein synthesis 

 and of growth in microorganisms. (Compare, however, recent observations 

 on the effect of 5-fluorouracil on a uracil -requiring mutant of E. coli. 6la ) 



Recent investigations showed that the RNA which is synthesized in bac- 

 terial cells in the absence of protein synthesis, is physiologically inferior and 

 incapable of a prolonged existence in the cell since it undergoes a rapid and 

 continuous disintegration to products of low molecular weight. 62 " 65 



It should be noted, however, that several investigations have shown the 

 absence of a direct correlation between the rate of growth and protein 

 synthesis and the RNA content of bacteria. For example, all species with 

 a more rapid speed of multiplication, when compared to more slowly grow- 

 ing strains, can have a lower RNA content in both resting and dividing 

 cells and can be characterized by an even smaller RNA accumulation (ab- 

 solutely and relatively) when going from the resting to the dividing cell. 66 

 A series of studies by .Beljanski 6771 on Staphylococcus aureus and E. coli 

 showed that antibiotic-resistant strains, obtained by means of the cultiva- 

 tion of original strains on media containing the antibiotic, when grown on 

 ordinary media (without antibiotic) accumulate, in all cases, considerably 



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61 C. Lark and K. G. Lark, J. Bacteriol. 76, 666 (1958). 



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62 F. C. Neidhardt and F. Gros, Biochim.. et Biophys. Acta 25, 513 (1957). 



63 F. E. Hahn, M. Schaechter, W. S. Ceglowski, H. E. Hopps, and J. Ciak, Biochim. 

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64 M. G. Harrington, J. Gen. Microbiol. 18, 767 (1958). 



66 J. Horowitz, A. Lombard, and E. Chargaff, J. Biol. Chem. 233, 1517 (1958). 



66 H. E. Wade and D. M. Morgan, Biochem. J. 65, 321 (1957). 



67 M. Beljanski, Ann. inst. Pasteur 83, 80 (1952). 



68 M. Beljanski, Compt. rend. acad. sci. 236, 1102 (1953). 



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70 M. Beljanski, Ann. inst. Pasteur 84, 756, 760 (1953). 



71 M. Beljanski, Ann. inst. Pasteur 85, 463 (1953). 



