Yoshinori Nishizawa

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Counter-selection is a useful gene manipulation technique for repeated gene disruptions, gene shufflings and gene replacements in yeasts. We developed a novel counter-selection system using a galactose-inducible growth inhibitory sequence (Kawahata et al.1999. Yeast 15: 1-10). This counter-selection marker, named GAL10p-GIN11, has several advantages over(More)
To increase eicosapentaenoic acid (EPA, 20:5, n-3) content in the marine alga Nannochloropsis sp., the effect of CO2 concentration during cultivation has been investigated. In a batch culture under normal atmospheric conditions (0.037% CO2), the EPA content per cell increased during the first 1.5 days and then decreased immediately even though the cells(More)
Auxotrophic mutants of the yeast Saccharomyces cerevisiae are usually isolated in haploid strains because the isolation of recessive mutations in diploids is thought to be difficult due to the presence of two sets of genes. We show here that auxotrophic mutants of diploid industrial sake yeast strains were routinely obtained by a standard mutant selection(More)
Point mutation of Gly1250Ser (1250S) of the yeast fatty acid synthase gene FAS2 confers cerulenin resistance. This mutation also results in a higher production of the apple-like flavor component ethyl caproate in Japanese sake. We mutated the 1250th codon by in vitro site-directed mutagenesis to encode Ala (1250A) or Cys (1250C) and examined cerulenin(More)
Drug-resistance markers for yeast transformation are useful because they can be applied to strains without auxotrophic mutations. However, they are susceptible to technical difficulties, namely lower transformation efficiency and the appearance of drug-resistant mutants without the marker. To avoid these problems, we have constructed a phosphoglycerate(More)
The commercial application of genetically modified industrial microorganisms has been problematic due to public concerns. We constructed a “self-cloning” sake yeast strain that overexpresses the ATF1 gene encoding alcohol acetyltransferase, to improve the flavor profile of Japanese sake. A constitutive yeast overexpression promoter, TDH3p, derived from the(More)
For the production of a herbicide, 5-amino-levulinic acid (ALA), from anaerobic digestion liquor, the utilization of the photosynthetic bacterium, Rhodobacter sphaeroides was examined. This bacterium could produce ALA extracelularly from this liquor with the addition of levulinic acid (LA), an inhibitor of ALA dehydratase (ALAD), and glycine, a precursor of(More)
Chlorogenic acid, a polyphenol found in coffee, has antihypertensive actions, but epidemiologic data on the effects of coffee on blood pressure are controversial. Specific coffee components that inhibit the hypotensive effect of chlorogenic acid and the physiologic mechanisms underlying the effects of coffee without these components were investigated. One(More)
Various auxotrophic mutants of diploid heterothallic Japanese sake strains of Saccharomyces cerevisiae were utilized for selecting mating-competent diploid isolates. The auxotrophic mutants were exposed to ultraviolet (UV) irradiation and crossed with laboratory haploid tester strains carrying complementary auxotrophic markers. Zygotes were then selected on(More)
BACKGROUND/AIM Indoleamine-2,3-dioxygenase (IDO) is a rate-limiting enzyme for tryptophan metabolism and plays an immunosuppressive role. Antigen-presenting cells, when activated, increase the expression of IDO, which results in the suppression of subsequent immune reaction. A novel IDO inhibitor, Toho-1, was explored for its applicability to immunotherapy.(More)