Yeast - Kobo

A type of fungus, it is a rounded eukaryote measuring 6-7 μm in size. It is unicellular for the majority of its life cycle and grows primarily by budding. As a model for eukaryotes, it is widely used in genetic analysis using mutants. Many of them have the ability to ferment carbohydrates into alcohol and carbon dioxide, and have long been used in the brewing of sake and soy sauce, as well as in the manufacture of bread. It is also used as a health food because it contains a lot of B vitamins. Although there are some uncertainties in the classification of yeast, approximately 40 genera and 350 species have been identified (corresponding to just under 0.8% of all fungi). The Saccharomyces genus has long been used in fermentation and brewing. It usually grows by budding, but it can also reproduce sexually as follows: First, cells fuse, then undergo meiosis to produce four ascospores. This process allows for tetrad analysis, making it a good source of genetic material. In addition, there are a variety of other yeasts, including fission yeasts such as Schizosaccharomyces pombe , which grow not by budding but by dividing through the formation of septa, the Candida genus, which causes candidiasis, and the Debaryomyces genus, which lacks fermentation ability.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

菌類の一種で，形状は丸みを帯び，大きさが6～7 μm の真核生物．生活環の大部分が単細胞であり，主として出芽によって増殖する．真核生物のモデルとして，突然変異体を利用した遺伝学的解析に広く用いられている．糖質をアルコールと二酸化炭素にかえる発酵能を有するものが多く，古くから酒，しょう油などの醸造や，パンの製造などに用いられている．ビタミンB群が多く含まれるので，健康食品としても扱われている．酵母の分類には不確かなところもあるが，およそ40属350種類が同定されている(菌類全体の0.8％ 弱に相当する)．Saccharomyces属は古くから発酵醸造に用いられている．通常は出芽によって増えるが，次のような有性生殖を行う場合もある．まず，細胞が接合し，ついで減数分裂を行って4個の子のう胞子をつくる．この過程を利用すると4分子解析が可能で，遺伝学のよい材料となっている．このほか，Schizosaccharomyces pombeのように，出芽ではなく，隔壁を形成して分裂することにより増殖するもの(fission yeast)，カンジダ症を引き起こすCandida属，発酵能を欠くDebaryomyces属など多様な酵母が存在する．

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