具有嗜杀质粒(killer plasmid)酵母菌嗜杀特性的初步研究

以K_2型嗜杀酵母为材料在改进Russell(1986)的嗜杀活性检测方法基础上,建立了双层平板单菌落检测法。此法可直接用于嗜杀酵母的筛选,嗜杀质粒的检测,并能在诱变后的平板上检出有嗜杀活性的营养缺陷型菌株MK_2-3:K~+,len。对K_2嗜杀特性初步研究表明,K_2型嗜杀酵母能杀死酿酒酵母(Saccha-romyces cerevisiae),但对所测汉逊酵母(Hansenula spp.)无作用。嗜杀毒素产生的最适pH和温度分别为pH4.5—5.5和20—25℃,酵母菌的对数生长期嗜杀毒素达到高峰。用紫外线(UV)、溴化乙锭(EB)、亚硝基胍(NTG)和甲基磺酸乙酯(EMS)进行消除K因子实验,表明亚硝基胍和紫外线对K因子具有一定消除率,而溴化乙锭和甲基磺酸乙酯未发现消除作用。

APRELIMINARY STUDY ON CHARACTERISITIC OF KILLER PLASMID IN YEAST

On foundation of improving Russell's method, with K_2 killer yeast, dilayer plate single colony assay for killer strain was set up. This assay may be directly used forselection and examination of killer yeast. An auxotroph strain with killing ability MK_2 -3K~+, Leu~- was obtained. Results of studing K_2 show that the yeast killed Saccharomyces cerevisiae but not Hansenula spp. tested in the experiment. The optimum conditions of producting killer toxin was pH 4.5-5.5 and 20-25C, and the peak value appears in logarithmic phase. Treating K_2 cells with UV and NTG were proved as eliminators of killer plasmid, but EB and EMS not.