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首页> 外文会议>Annual Biochemical Engineering Symposium; 20031005; Ames,IA; US >Development of Bacillus pasteurii Urease-Negative Mutants
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Development of Bacillus pasteurii Urease-Negative Mutants

机译：巴氏芽孢杆菌脲酶阴性突变体的开发

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摘要

Mutagens, ultraviolet light, and N-methyl-N'-nitro-N-nitrosoguanidine were used to develop urease-negative mutants of Bacillus pasteurii ATCC 11859. B. pasteurii produces urease in large quantity, up to 1% of its cell dry weight. Urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide. In a medium containing urea and calcium and carbonate ions, ammonia increases pH, inducing calcite precipitation. Calcite precipitation by B. pasteurii urease has been used as a tool in bioremediation of cracks in concrete and granite structures. This study, constructing recombinant bacteria over-expressing B. pasteurii urease, is part of the long-term goal of our research in urease-induced calcite precipitation. Seven stocks of urease-negative mutants were selected from the mutagen exposure. The possible urease-negative mutants in addition to the wild-type bacterium were tested for specific urease activity as well as calcite precipitation. Each of the possible mutants expressed low urease activity and induced little calcite precipitation compared to wild-type B. pasteurii. Current efforts focus on construction of urease-knockout mutants in B. pasteurii and restoration of urease activity by rescuing the urease-negative mutants developed through UV and NG mutageneses with a plasmid expressing B. pasteurii genes (pBU11).
机译：诱变剂，紫外线和N-甲基-N'-硝基-N-亚硝基胍被用于开发巴斯德巴斯德芽孢杆菌ATCC 11859的脲酶阴性突变体。巴斯德芽孢杆菌可大量生产脲酶，最高可达其细胞干重的1％。 。脲酶催化尿素水解成氨和二氧化碳。在含有尿素，钙和碳酸根离子的介质中，氨会增加pH值，从而引起方解石沉淀。巴氏杆菌尿素酶对方解石的沉淀已被用作对混凝土和花岗岩结构中的裂缝进行生物修复的工具。这项研究，构建过量表达巴斯德毕赤酵母脲酶的重组细菌，是我们研究脲酶诱导方解石沉淀的长期目标的一部分。从诱变剂暴露中选择了七种脲酶阴性突变体。除了野生型细菌外，还测试了可能的脲酶阴性突变体的特异性脲酶活性以及方解石沉淀。与野生型巴斯德毕赤酵母相比，每种可能的突变体均表现出较低的脲酶活性，几乎不引起方解石沉淀。目前的工作集中在巴氏杆菌中尿素酶敲除突变体的构建和尿素酶活性的恢复，方法是通过表达巴氏杆菌基因（pBU11）的质粒拯救通过UV和NG突变产生的尿素酶阴性突变体。

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