Techkarnjanaruk S, Pongpattanakitshote S, Goodman A E
School of Biological Sciences, Flinders University of South Australia, Adelaide, Australia.
Appl Environ Microbiol. 1997 Aug;63(8):2989-96. doi: 10.1128/aem.63.8.2989-2996.1997.
Sequence data for genes encoding 16S rRNA indicated that the marine strain previously named Pseudomonas sp. strain S9 would be better identified as a Pseudoalteromonas sp. By use of transposon mutagenesis, a chitinase-negative mutant of S9 with a lacZ reporter gene insertion was isolated. Part of the interrupted gene was cloned and sequenced. The deduced amino acid sequence had homology to sequences of bacterial chitinases. Expression of the chitinase gene promoter was quantified by measuring the lacZ reporter gene product, beta-galactosidase, beta-Galactosidase production was induced 10-fold by N-acetylglucosamine and 3-fold by chitin in minimal medium. Repression of beta-galactosidase synthesis was observed in rich medium either with or without chitin but was not observed in minimal medium containing glucose. The chitinase gene promoter was induced by starvation and higher-than-ambient levels of carbon dioxide but not by cadmium ion, heat or cold shock, or UV exposure.
编码16S rRNA的基因序列数据表明，先前命名为假单胞菌属S9菌株的海洋菌株更宜鉴定为交替假单胞菌属。通过转座子诱变，分离出了一个插入了lacZ报告基因的S9几丁质酶阴性突变体。对中断基因的一部分进行了克隆和测序。推导的氨基酸序列与细菌几丁质酶的序列具有同源性。通过测量lacZ报告基因产物β-半乳糖苷酶来定量几丁质酶基因启动子的表达，在基本培养基中，N-乙酰葡糖胺可使β-半乳糖苷酶产量诱导增加10倍，几丁质可使其增加3倍。在含有或不含有几丁质的丰富培养基中均观察到β-半乳糖苷酶合成受到抑制，但在含有葡萄糖的基本培养基中未观察到这种抑制现象。几丁质酶基因启动子可由饥饿和高于环境水平的二氧化碳诱导，但不受镉离子、热或冷休克或紫外线照射的诱导。
