INDUCED ENZYME FORMATION 



abrupt reversion of such positive cultures to the negative pheno- 

 type upon growth in the absence of inducer is in agreement with 

 the previous studies noted. 



The autocatalytic property of the enzyme-forming system 

 or some necesssary portion of it is here dramatically illustrated in 

 terms of the transmission of enzyme-synthesizing capacity from 

 mother to daughter cell. At least one is needed to make more 

 since, if by chance a cell is produced with none, it and its progeny 

 are negative. 



The results obtained on the inheritance of the ability to 

 form galactozymase parallel in many respects the prior investi- 

 gations of Ephrussi (23) and his co-workers into the "petite" 

 mutant. The data of these workers also suggest the existence of 

 randomly distributed particulate elements in the cytoplasm pos- 

 sessing autocatalytic properties and responsible for the produc- 

 tion of cytochrome oxidase. The autocatalytic nature is again 

 exhibited by the spontaneous occurrence of cells lacking the 

 particles which lead to the irreversible loss of the ability to form 

 the corresponding enzymes. 



It has been possible to demonstrate (89) that the particu- 

 late elements involved in the two instances are distinct en- 

 tities, since the two enzyme-forming capacities are lost sepa- 

 rately. In the "petite" mutant case control of the number of 

 elements of the cell is apparently not achieved by variation of 

 inducer availability. However, cells lacking particles can be 

 produced by treatment with the acridine dye, euflavine. It is of 

 interest to note that Slonimski (69,70) has been able to demon- 

 strate that this compound which is so effective in preventing the 

 transmission of the particles from mother to daughter cells also 

 specifically inhibits their ability to form enzyme. 



One can go beyond an independent exhibition of the 

 autocatalytic nature of the enzyme-forming mechanism. The 

 possibility of controlling active particle numbers in the case of 

 the slow adaption to galactose provided an experimental system 

 which permitted a further analysis on the role of inducer and its 

 relation to the active particles and enzyme. 



139 



