Bhuiyan F A, Nagata S, Ohnishi K
Department of Applied Bioresource Science, The United Graduate School of Agricultural Sciences, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime, 790-8566, Japan.
Pak J Biol Sci. 2011 Feb 1;14(3):204-11. doi: 10.3923/pjbs.2011.204.211.
Chitinase degrades chitin which comprises an important source of carbon and nitrogen in the marine environment. The aim of this study was to evaluate the population of chitinases in the marine sediments in southwest Japan. We collected marine sediments from eutrophic inner bay and offshore. Chitin-degrading bacteria were enriched from both sediments. Metagenomic DNA was isolated from the enriched chitin-degrading bacterial cell culture. At the same time, 25 chitin-degrading bacteria were isolated from the enriched culture. Partial fragments of chitinase genes were successfully amplified with degenerate primers designed for the glycoside hydrolase 18 family. We analyzed chitinase gene sequences of about 500 clones from metagenomic DNA prepared from chitin-degrading bacteria. Based on translated amino acid sequences, chitinases were grouped into five groups. Chitinases in groups II and III was most abundant and close to chitinase genes of several species of proteobacteria. On the other hand, chitinases in groups I, IV and V were unique and distinct from the known chitinases. These results indicate that the marine sediments used in this study contain diversity of chitinase genes.
几丁质酶可降解几丁质，而几丁质是海洋环境中重要的碳和氮源。本研究的目的是评估日本西南部海洋沉积物中几丁质酶的种群情况。我们从富营养化的内湾和近海采集了海洋沉积物。从这两种沉积物中富集了可降解几丁质的细菌。从富集的可降解几丁质的细菌细胞培养物中分离出宏基因组DNA。同时，从富集培养物中分离出25株可降解几丁质的细菌。用针对糖苷水解酶18家族设计的简并引物成功扩增了几丁质酶基因的部分片段。我们分析了从可降解几丁质的细菌制备的宏基因组DNA中约500个克隆的几丁质酶基因序列。根据翻译后的氨基酸序列，几丁质酶被分为五组。第二组和第三组中的几丁质酶最为丰富，且与几种变形菌门细菌的几丁质酶基因相近。另一方面，第一组、第四组和第五组中的几丁质酶则很独特，与已知的几丁质酶不同。这些结果表明，本研究中使用的海洋沉积物含有多种几丁质酶基因。
