MECHANISM OF COMPETITION IN YEAST CELLS 



87 



species under anaerobic conditions, with a low level of biomass, it 

 begins to grow rapidly with an access of oxygen and in its prop- 

 erties approaches Saccharomyces. The maximal volumes and 

 coefficients of geometric increase given in Table VI show these 

 regularities in a quantitative form. When there is no oxygen and 

 fermentation is the only source of available energy, the coefficient 

 of geometric increase in Schizosaccharomyces is very low and equal to 

 0.04375. Under the influence of oxygen this coefficient increases 



Saccharomyces aerobic , 



Saccharomyces anaerobic 



K=6 9 



Schizosaccharomycef aerobic 



j i_ 



J •- 



IO 20 30 VO So 



Schizosaccharomyces anaerobic 



K*3.Q o 



10 



20 



30 



VO 



SO 



Hours 



160 



Fig. 17. The growth in volume of Saccharomyces cerevisiae and Schizosac- 

 charomyces kephir cultivated separately and in the mixed population under 

 aerobic and anaerobic conditions (1932). All curves are drawn according to 

 equations. 



4.3 times and attains 0.18939, whereas in Saccharomyces the coeffi- 

 cient of geometric increase under the same conditions rises but slightly 

 (from 0.21529 to 0.28769). 



The sharp changes in the properties of our species under aerobic 

 conditions produce a completely new situation for the growth of a 

 mixed population (see Fig. 17). As before, we have calculated the 

 coefficients of the struggle for existence and Table VII shows that 

 they differ considerably from the anaerobic ones. If in anaerobic 

 experiments the coefficient a, which characterizes the intensity of in- 



