我国各类基物上的酵母菌分布及其尿素酶活性

本文讨论了2300株由我国各地分离到的酵母菌和类酵母菌与各类基物的关系。共述及23属,占Lodder(1970)系统的半数以上。在十几类基物中酵母菌的分布各有不同,叶子上有大量掷孢酵母,果实上比其它基物更能获得克勒克酵母属(Kloeckera),在咸腌食品中相对地有较多耐高渗透压的酵母如球拟酵母属(Torulopsis)与德巴利酵母属(Debaryomyces)。对部分属的定种工作也已进行,说明某些属的种在我国均有发现而且为数不少。此外还研究了600余株代表各类酵母的尿素酶活性,结果说明担子菌酵母或系统上接近担子菌的酵母都有尿素酶活性,而子囊菌酵母则无。根据作者的观察子囊菌酵母中裂殖酵母属(Schizosaccharomyces)则常常例外地有尿素酶反应,且常有辅酶Q_(10),从而可见裂殖酵母属有其特有的生物学特性,在系统上很可能与其它子囊菌酵母不同。对属于不完全菌的无孢子酵母也进行了尿素酶活性测定,结果表明它们部分与子囊菌有关,部分与担子菌有关。

STUDIES ON YEASTS ON DIFFERENT SUBSTRATES IN CHINA AND THEIR UREASE ACTIVITY

During the last ten years, a survery of the yeasts in nature has been conducted. Several thousand strains of yeasts have been isolated from sample of flowers, leaves, tree exudates, soils feces of insects, birds and animals collected from high mountains and forests in various regions of different provinces in China as well as from sea water. Many kinds of foodstuff such as canlied fruits, salted foods, decaying foods, grains, ect., are also examined. Discussion on the distribution of more than two thousands yeasts and yeast-like fungi representing 23 genera has been made. Species of Schizosaccharomyces, Rhodotorula, Sporobolomyces, Bullera and others have been identified, the urease activity of some of them has been studied. The basidiomycetous yeasts and their related yeasts are characterized by their ability to hydrolyze high concentrations of urea, while all ascomycetous yeasts except Schizosaccharomyces are not able to do so. In the asporogenous yeasts, all strains of Rhodotorula and Cryptococcus investigated are urease-positive. As for Torulopsis and Candida, only a part of them shows urease activity. Hence, some strain of these two genera are thought to be closely related to basidiomycetous yeasts. Most of the Schizosaccharomyces resemble basidiomycetous yeasts not only in the ability of utilizing urea, but also in having coenzyme Q_(10) as well as in the difficulty of obtaining mannan recipitate when using 2％ KOH to liberate manmose-containing polysaccharides from their cell wall. In these respects, Schizosaccharomyces is quite different from the other ascomycetous yeasts.