Yasuyuki Uzuka

Fractionation and Anti-tumor Activity of the Mycelia of Liquid-cultured Phellinus linteus

All the fractions of Phellinus linteus mycelia showed anti-tumor activity toward solid tumors planted in mice. The highest anti-tumor activity of 81.2% was observed in the protein–glucan complex obtained by precipitating the 24% NaOH extract at pH 6.0. This protein–glucan complex consisted of 39.3% polysaccharide and 49.4% protein. Its 13C- and 1H-NMR data showed that the main glucan part of the complex was simple α-1,3-glucan chains.

An Improved Method for Isolating Yeasts in the Genus Lipomyces and Related Genera from Soil

An improved method for isolating soil yeasts in the genus Lipomyces and related genera was developed on the basis of their physiological properties. Liberation of yeast cells from soil, capture of the yeast cells by a membrane filter, and colony formation on an acidic (pH 3) nitrogen-free agar plate containing 0.1% cycloheximide resulted in success.

Total DNA Preparation Excluding Extracellular Acidic Polysaccharide from Lipomyces Yeasts and its Application to Taxonomic Studies

A preparation method of total DNA from Lipomyces yeasts was improved in order to exclude extracellular acidic polysaccharide thoroughly. The method combined an ultracentrifuge and polyethylene glycol precipitation with the usual method. The total DNAs obtained were analyzed for G+C content and by DNA-DNA hybridization. The results all agreed almost completely with literature data. All the DNA samples prepared using this method were pure enough for these taxonomic analyses and could also be used as templates of PCR for amplification of small subunit ribosomal DNA and the internal transcribed spacer region.

Analysis of mitochondrial DNA restriction fragment length polymorphisms for examining genetic variability among isolates of Phellinus linteus

Abstract Restriction fragment length polymorphism (RFLP) analysis of mitochondrial DNAs (mtDNAs) from nine Japanese wild isolates of Phellinus linteus was carried out to examine their genetic variability. BamHI and EcoRI digests of mtDNAs from these isolates produced four and five distinct RFLP patterns, respectively. By combining the RFLP patterns obtained with the two endonucleases, mtDNAs from the nine isolates could be assigned to five different genotypes, but no mtDNA variation was detected among the isolates collected from a small area. Distance values calculated among all pairs of mtDNA genotypes, based on the presence or absence of comigrating restriction fragments, were clearly smaller than those among the mtDNA genotypes of Lentinula edodes and Pleurotus ostreatus samples collected worldwide, suggesting the necessity of collecting P. linteus wild isolates for genetic resources from geographically wider areas.

Transfer of sulfite in medium to the cells of wine yeast.

1) pH7.0の培地に酸性亜硫酸ナトリウムを520.3mg/l (5mM) 添加して培養したところ, 初期生育は活発であったが, その後, 徐々に生育が遅れ, 再び活発な生育を示した。2) 培養開始時に存在した遊離型亜硫酸は酵母の生育に伴って減少し, 約20時間後にほとんど全てが結合型亜硫酸に変化した。3) NaH35SO3を用いたラジオアイソトープ実験の結果, 培地に添加した亜硫酸のうちSO2ガスとして放出される部分はなかった。4) 培養中に総亜硫酸量が減少するのはラジオアイソトープ実験とBioassayの結果から, SO32-の一部が不揮発性硫黄化合物に変化するからであると考えられた。5) 菌体画分の35Sのうち約99%はSO32-として培地から移行したものであり, 残り1%は培地中でSO32-から不揮発性硫黄化合物に変化した後に菌体に移行した。