Phenotypically Unstable Mutants

and 518-4 (grown for 3-4 generations at 18°C) is shown to increase when cells are incubated at 28°C in a nongrowth medium. This temperature adaptation phenomenon is remarkably similar to the classical respiratory adaptation of repressed yeast cells in response to oxygen or release from catabolite repression both can occur under conditions of nongrowth and both require cytoplasmic as well as mitochondrial translation products.  

At present, it cannot be decided if steps I and II represent obligatory pathways of mitochondrial development during derepressed aerobic growth. 

In terms of both the relative amounts and the total extent of synthesis of mitochondrial translation products, promitochondria do not differ much from mitochondria in fully derepressed cells. In order to determine if the 

An analysis of the cytochrome content in cells of the cold-sensitive strains grown at 18°C revealed a complete loss of cytochrome oxidase absorbance and a significant reduction in the level of absorbance of cytochromes b and In effect, these strains resemble some nuclear 

Diploids were grown at 18°C on 2% galactose. Cells were harvested in early-stationary phase and were resuspended in 50 mM KPO4 (pH 7.4) and 1% ethanol. Aliquots were removed for measurements of respiratory activity. 

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