苏云金素高产菌株的选育

用硫酸二乙酯(DES)处理苏云金杆菌CT-43菌株,得到了菌落形态、菌形和产生褐色素三种类型的突变株。光滑型(S-型)菌落自发突变的比例依亚种的不同而不同,CT-43菌株高达13.0％,苏云金亚种为10.6％,以色列亚种为3.9％,库斯塔克亚种不产生S-型菌落,S-型菌落依DES处理CT-43菌株芽孢时间的延长而增加,处理90分钟达49.0％。除个别S-型菌落外,均不产生苏云金素。诱变产褐色素菌落的频率为1.4％,它们都不产苏云金素。菌形变异株有仅芽孢,仅伴孢晶体,芽孢和伴孢晶体,营养体和芽孢,营养体和伴孢晶体,营养体、芽孢和伴孢晶体发生变异六种类型,它们产生苏云金素的水平各不相同。还获得了苏云金素产量比出发菌株明显提高的二个菌株。

BREEDING OF THE STRAINS OF HIGH-YIELD OF THURINGIENSIN YU Ziniu QIU Liyou LI Zeying

After Bacillus thuringiensis some strains are treated with Diethylfu-1phur ( DES ) , the mutants of colony with cell morphology, and produced black pigment are gained. The proportions of S-colony naturally produced by several subspecies of B. thuringiensis are differert, CT-43 strain is 13.0%, subsp. thuringiensis is 10.6%, subsp. israelensis is 3.9%, and subsp. kurstaki is 0%.The count of S-colony increase with prolong of DES treated time, when the spores of CT-43 strain are treated at 90 minutes, S-colonies are 49.0%, The cells of S-colonies do not produce the thuringiesin besides one S-colony. The frequency of produced black pigment mutaut is 1.4%, all of them do not produce thuringiensin also. There are six typies of cell morphology mutants:the spores; the crystals; the spores and crystals; the vegetable cell and spores; the nutritional cell and crystal; and the vegetable cell, spore and crystal.The levels of produced thuringiensin by above mutants are different .Two mutants of them can produce thuringiensin more than it of produced by original strain.