title: Polyamine auxotrophs of Saccharomyces cerevisiae.
abstract: Strains of yeast have been constructed that are unable to synthesize ornithine and are thereby deficient in polyamine biosynthesis. These strains were used to develop a protocol for isolation of mutants blocked directly in polyamine synthesis. There were seven mutants isolated that lack ornithine decarboxylase activity; these strains exhibited greatly decreased pool levels of putrescine, spermidine, and spermine when grown in the absence of polyamines. Three of the mutants lack S-adenosylmethionine decarboxylase activity; polyamine limitation of a representative mutant resulted in an accumulation of putrescine and a decrease in spermidine and spermine. When the mutants were cultured in the absence of polyamines, a continuously declining growth rate was observed.
mesh_terms: D012437:Adenosylmethionine Decarboxylase / Q000378:metabolism; D005796:Genes; D005816:Genetic Complementation Test; D008040:Genetic Linkage; D009952:Ornithine / Q000096:biosynthesis*; D009955:Ornithine Decarboxylase / Q000378:metabolism; D011700:Putrescine / Q000096:biosynthesis*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D013095:Spermidine / Q000096:biosynthesis*; D013096:Spermine / Q000096:biosynthesis*
chemical_list: D013096:Spermine; D009952:Ornithine; D009955:Ornithine Decarboxylase; D012437:Adenosylmethionine Decarboxylase; D013095:Spermidine; D011700:Putrescine