DORMANCY 



8-8 



Table 8-3 



Respiratory and Feruentative Activity of Yeast Con- 

 taining Visible Deposits of Mitochondria and Glycogen* 



*The Q values of these veasts without visible deposits (in 

 glucose) were: Qo^lO-UT , QcQ 160-432, QcO 241-308. The one low 

 OOn value probably indicates that this culture contained dead cells. 



Accumulated carbohydrates are responsible for the lag in growth 

 observed on the inoculation of the fresh medium. The lag can be 

 minimized or eliminated if the ceils are transferred before storage 

 has occurred. 



Hansen developed a technique of preserving yeast cultures by 

 suspending them in 10 per cent sucrose solution and sealing the 

 flask to prevent evaporation. Observation of such suspensions 

 shows many autolyzed cells and others richly loaded with mitochon- 

 dria. Presumably, the strong sucrose solution causes the autoly- 

 sis of some cells and the formation of fat occurs in the presence of 

 of the autolysate and the high sugar concentration. This results in 

 the production of dormant cells. Hansen's procedure could not be 

 used to supply dormant cells in our experiments because a very 

 large percentage of the cells die in high concentrations of sugar 

 and only a few attain full dormancy. Winge and Hjort (1935) re- 

 covered living cells from 47-year-old sucrose suspensions of yeast 

 cells prepared by Hansen. 



The fact that dormant cells do not break dormancy except in 

 medium containing a relatively full complement of nutrients pre- 

 vents the dormant cells from growing except under conditions that 

 assure continued growth. The fact that they require specific vita- 

 mins which they are unable to synthesize may have some import- 

 ance in solving the problem of inducing other fxmgal spores to ger- 

 minate. 



These facts are consistent with the view that the mitochondria 

 contain ribose nucleoprotein insulated from the cytoplasm by lipoid. 



