27-7 



THE YEAST CELL 



both large and small colonies, and the variations in colony size on 

 this agar cannot be due to genetic differences because they all a- 

 rise from a recent single colony. Fig. 27-3 shows the results of 

 plating serially on M and C media. 



M 



100% L 



M 



100% L 



Vi as many as on M 

 90% L 10% S 



M 



100% L 



4 



c 



% as many as 



on M, 

 70% L 

 ^Q% S 



M 



100% L 



M 



100% 



c 



Same No. as on M 

 100% L 



Hdi 1 day 

 in eo!d roofn 



in.C Broth 



99.9%L 

 /% S 



c 



'/3ai many asonM 

 70% ■ ' 

 30% 



Same No. 

 asonM 

 100% L 



c 



60% L 

 40% S 

 2 0,000 Colonies 



il 



M 



9D%L 

 10 % S. 



5)000 Colonies 



c , 



Same No.ason M 

 95% L 

 5%S 



Neld Tdays 

 in cold room 

 in C Broth 



/ \ 



M C 



100^ L 



i 



.}^eld 7 days 

 in eold room 

 ixiC Broth 



Held 1 days 



in cold room 



C Broth 



m C Broth in C Broth 



/ \ / V 



■)f No Comparison possible 



Same No. as 



onM 



20% L 



70% S 



10% extremely S- 



M 



33% L 

 7% S 



1 0^000 

 Colonies 



Same No. as 

 on M 

 69% L 

 JO'% S 

 i % extremely S 



M 



loo%L 



c 



Same No.as 

 on M 

 10% L 

 80% S 

 10 % extremely S 



Fig. 27-3 Adaptation of the Illegitimate R-strain grown on malt 

 extract Medium (M) to corn steep water medium (C) as indicated by the 

 number of colonies surviving transfer and size of colonies. (L = large 

 colonies; s= small colonies 



One of the large colonies from M agar was suspended in water, 

 and equal amounts of the suspension planted on M and C agar. All 

 the colonies appearing on the M plate were uniformly large. Only 



