Characterization and isolation of mutants producing increased amounts of isoamyl acetate derived from hygromycin B-resistant sake yeast.
Hygromycin B is an aminoglycoside antibiotic that inhibits protein synthesis in prokaryotes and eukaryotes. Twenty-four hygromycin B-resistants mutants were isolated from sake yeast, and were divided into three different degrees of strength according to hygromycin B resistance. Three of four hygromycin B strongly resistant mutants produced increased amounts of isoamyl acetate in sake brewing test, although isoamyl alcohol levels remained unchanged. Many hygromycin B-resistants mutants showed higher E/A ratios than K-701 in culture with koji extract medium. Strain HMR-18 produced the largest amount of isoamyl acetate, and its alcohol acetyltransferase (AATFase) activity was 1.3-fold that of K-701. DNA microarray analysis showed that many genes overexpressed in HMR-18 were involved in stress responses (heat shock, low pH, and so on) but HMR-18 showed thermo- and acid-sensitivity. It was strongly resistant to hygromycin B and another aminoglycoside antibiotic, G418.
Nihonsakari Co., Ltd., Nishinomiya, Hyogo, Japan. toyohisa.inoue@nihonsakari.co.jp
Toyohisa
T
Inoue
Haruyuki
H
Iefuji
Haruo
H
Katsumata
D000123:Acetyltransferases / Q000378:metabolism; D000434:Alcoholic Beverages / Q000382:microbiology*; D002172:Canavanine / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D025141:Drug Resistance, Fungal / Q000235:genetics*; D006921:Hygromycin B / Q000494:pharmacology*; D007930:Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D000439:Pentanols / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D013312:Stress, Physiological
D000439:Pentanols; D002172:Canavanine; D006921:Hygromycin B; D000123:Acetyltransferases; D007930:Leucine; C020377:isoamyl acetate