STRUCTURAL AND CHEMICAL ARCHITECTURE OF HOST CELLS 



103 



or absence of antibiotic were found to possess identical base compositions 

 (Pardee and Prestidge, 1956). 



IV. Patterns of Polymer Synthesis 



A. Exponential Growth 



From the point of view of the virologist, it is most useful to have suspen- 

 sions of separate and viable cells which, when mixed with virus, will act as 

 discrete separate units subject to the relatively simple statistics of a Poisson 

 distribution. Much of the important progress in the study of the bacterio- 

 phages was possible because these conditions were met in the mixing of 



Q- 20 



O en 



O ^ 



• Protein nitrogen 

 ° Cell concentration 



20 40 60 80 100 120 

 (hr) 



20 40 60 80 100 

 (hr) 



Fig. 16. Increase in population, RNA, and DNA of L cells propagated in suspension. 

 Increase in population and cellular protein nitrogen of a similar culture (Siminovitch 

 et al, 1957). 



bacteria and virus, and the recognition that progress with animal viruses 

 might similarly be facilitated has in recent years evoked considerable effort 

 to prepare animal cells in a manner comparable to bacterial suspensions. An 

 example of outstanding success in this direction has been provided by Simino- 

 vitch et al. (1957), who have grown various animal cells derived from the 

 progeny of a single cell, e.g., mouse L cell, monkey kidney ceU, in suspension 

 in tissue culture. 



The kinetics of cell multipHcation and of the parallel increments of protein, 

 DNA, and RNA are fuUy comparable to those of exponential growth of a 

 bacterial culture, e.g., E. coli m a glucose-mineral medium, as given in Fig. 16. 

 Furthermore, the L cells will support the multiphcation of various animal 

 viruses, e.g., vaccinia, herpes simplex, and be lysed by them, in a manner 

 analogous to a virulent phage-bacterium system. 



