32. THE NUCLEIC ACIDS OF MICROORGANISMS 155 



more RXA in the lag-phase than do the original strains. Moreover, in most 

 cases, resistant strains were distinguished by a more prolonged lag-phase 

 and a slower speed of multiplication during the logarithmic phase. These 

 data were also confirmed with other bacteria. 72, n 



Heden et al., 74 applying continuous cultivation techniques, also pointed 

 out the absence of a correlation between the nucleic acid content in steady- 

 state cells and the rate of growth. 



Two circumstances should be borne in mind here. First, it has not been ruled out 

 that it is not the total RXA of the cell but rather the "additional RXA" which can be 

 correlated with the rate of growth and protein synthesis, i.e., that portion of the RXA 

 which is responsible for the basophilia of cells. 3 ' 7 - 66 75 It is just this RXA which 

 accumulates in the lag-phase above the constant amount of the basic RXA which is 

 always present in the cells, and it is this former which gradually disappears with the 

 slowing down of growth and synthetic processes and is lacking in resting cells. 3 - 743 - 

 so, 66.-5 Proportions of these two RXA fractions, the "additional" (fluctuating) and 

 the "basic" (constant) one, may be different in different strains and species of micro- 

 organisms, 66 and this makes it difficult to draw parallels between the rate of growth 

 and the content of total RXA. Second, even when taking into consideration the 

 "additional" (fluctuating) RXA, one cannot always solve the problem of the direct 

 correspondence of the amount of this RXA to the rate of growth and protein syn- 

 thesis. One may suppose that not all of this RXA, but only a certain portion of it 

 which varies from species to species, participates in the synthesis of the bulk of the 

 proteins. Besides, the accumulation of the same amount of proteins in the same time 

 may require a different amount of RXA in different species, depending on the quality 

 of these proteins, their half-life, etc. At any rate, even if there often exists a correla- 

 tion between RXA accumulation and the rate of growth, the comparison of different 

 species and strains of bacteria shows that it does not follow a general rule as is the 

 case in the analysis of the same organism in various states and conditions. 



With respect to such kinds of variability as the formation of involutionary 

 forms of bacteria, transition to the L-form, etc., it should be noted that a 

 considerable increase of the DNA/RNA ratio is recorded in the literature. 

 Apparently, this is mainly attributable to the lowered RXA content in 

 such forms, 55 - 56 - 7678 but may to a certain degree, at any rate in some cases, 

 also be due to an increased DNA content. 37 



72 J. Smolens and A. B. Vogt, J. Bacteriol. 66, 140 (1953). 



73 V. I). Tymakov, D. G. Kudlaj, V. G. Petrovskaja, A. M. Korneeva, and L. A. 

 Kodina, Zhur. mikrobiol. epidemiol. immunobiol. Xo. 8, 3 (1957). 



74 C.-G. Hed<m, T. Holme, and B. Malmgren, Acta Pathol. Microbiol. Scand. 37, 50 

 (1955). 



75 H. E. Wade and D. M. Morgan, Nature 176, 310 (1955). 



76 R. Vendrely and R. Tulasne, Bull. soc. chim. biol. 34, 785 (1952). 



77 R. Vendrely and R. Tulasne, Nature 171, 262 (1953). 



78 (). Kandler, C. Zehender, and J. Muller, Arch. Mikrobiol. 24, 219 (1956). 



