7 



The Influence of Conditions of Culture on 

 Certain Soluble Macromolecular Components 



of Escherichia colt 



S. DAGLEY J- SYKES 



Department of Biochemistry, University of Leeds, England 



Schachman, Pardee, and Stanier [1] used the analytical ultracentrifuge to 

 examine soluble extracts prepared from various bacterial species disrupted by 

 different methods, and they showed the presence in all extracts of three major 

 components having sedimentation coefficients (uncorrected) of about 40, 29, 

 and 5 S. Other workers (Siegel, Singer, and Wildman [2] and Billen and 

 Volkin [3]) have obtained ultracentrifuge patterns in substantial agreement. 

 For the strain of Escherichia coli we have used, a typical "basic" pattern is seen 

 in figure 3a, where the boundaries, reading from left to right, sediment re- 

 spectively at 40, 29, and 20 S followed by a large, slow-moving peak which, on 

 centrifuging for longer periods, resolves into two peaks of 8 and 5 S. Although 

 the ultracentrifuge has revealed a common pattern of macromolecules, how- 

 ever, the ever-increasing range of enzymes shown to be induced in bacteria 

 supports the assertion that they are "the most plastic of living material" (Ste- 

 phenson [4]); and accordingly we have tried to find out whether changes in 

 their environment have any influence upon the ultracentrifuge pattern. 



This work may be divided into two parts. First, we examined the basic ultra- 

 centrifuge pattern for modifications that might result from growth of the cells 

 on different sources of carbon; and we also determined rates of sedimentation 

 of certain enzymes, some of which were induced by addition of substrates to 

 cultures, in order to decide whether any of them appeared to be associated with 

 macromolecules revealed by ultracentrifugal analysis. The second series of 

 experiments was concerned with factors affecting the concentration of the 40 S 



component inside the living cells. 



62 



