枯草芽孢杆菌rocG基因插入失活突变株的构建

枯草芽孢杆菌中有2个编码谷氨酸脱氢酶(GDH)的基因:rocG基因和gudB基因。其中Bacillus subtilis 168菌株的rocG基因编码有活性的GDH,而gudB基因编码没有活性的GDH。敲除168菌株的rocG基因后,gudB基因会自发突变为gudB1基因,后者编码有活性的GDH(gudB1-GDH)。为了研究gudB1-GDH在代谢中的作用及调控机制,构建了pMUTin4-rocG插入突变重组质粒,将其转化至B.subtilis 168,成功获得了1株rocG失活突变株BS-△rocG。对BS-△rocG和野生株的生长情况及GDH酶活进行了比较,发现BS-△rocG生长情况和野生株相当,但其GDH酶活为4.641U/mg蛋白,高于野生株的3.042U/mg蛋白。由此推测BS-△rocG中,gudB可能自发突变为gudB1,从而能够编码有活性的GDH,这一结果为研究枯草芽孢杆菌gudB1-GDH在代谢中的作用及调控机制奠定了基础。

Construction of the Insertionally Inactivated Mutation of rocG Gene in Bacillus subtilis

In order to explore the influence of irrigation upper control limit by small tube flow to the accumulated soil temperature, fruit growth index etc. of wine grape, adopting the field cultivation experimental method, carried out the irrigation test with small tube flow on wine grape. The results showed that: The accumulated soil temperature was decreased with increasing soil depth, the accumulated soil temperature with fruit growth was presented a positive correlation relationship. The small tube flow was more useful to increase the accumulated soil temperature and fruit growth compared with the furrow irrigation. When the irrigation upper limit was 90% of field capacity, the grape fruit diameter, single fruit ear weight total were higher than other treatments with highest yield, compared with control treatment the yield was increased 44.95%, the difference was significant (P<0.01). When the irrigation upper limit was 80% of field capacity, the grape fruit acid was minimum, the sugar content was maximum up to 236.17 g·L^-1. It was indicated that 90% of field capacity was the irrigation upper limit for optimal adding production, the irrigation upper limit of 80% field capacity was the best useful to improve grape quality.