title: Population analysis of the deinduction kinetics of galactose long-term adaptation mutants of yeast.
abstract: By use of a selective galactose agar medium containing ethidium bromide, a population analysis of the deinduction kinetics of yeast galactose long-term adaptation mutants (gal 3) has been done. It was first determined that the gal 3 mutation is specific to the yeast galactose system and that induced cultures of gal 3 strains are capable of growth on galactose agar medium containing ethidium bromide, whereas noninduced cultures are not. Population analyses of induced gal 3 strains under going deinduction in the absence of galactose demonstrate that a minimum number of five induction units per cell are required for induction of the galactose system. It is concluded that: these induction units are actively synthesized only in the presence of inducer and are diluted out through cell division; they are stable under nongrowing conditions; they are heterogeneous in nature; at most two of the five minimum units are products of the gal 2 locus; and the other units may be three of one type, one of one type and two of another, or one each of three different types.
mesh_terms: D004790:Enzyme Induction; D004996:Ethidium / Q000494:pharmacology; D005690:Galactose / Q000378:metabolism*; D005838:Genotype; D005947:Glucose / Q000378:metabolism; D007700:Kinetics; D026901:Membrane Transport Proteins / Q000378:metabolism; D009154:Mutation / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000378:metabolism*
chemical_list: D026901:Membrane Transport Proteins; D004996:Ethidium; D005947:Glucose; D005690:Galactose