生物工程學報 Chin J Biotech 2008, March 25; 24(3): 395-400
journals.im.ac.cn Chinese Journal of Biotechnology ISSN 1000-3061
[email protected] . 2008 Institute of Microbiology, CAS & CSM, All rights reserved
張薇1,2, 魏海雷3, 高洪文2, 黃國和1
1 華北電力大學能源與環(huán)境研究中心, 北京 102206
2 中國農業(yè)科學院北京畜牧獸醫(yī)研究所, 北京 100094
3 中國科學院微生物研究所, 北京 100101
摘 要: 中度嗜鹽菌Bacillus alcalophilus DTY1 分離自晉西北黃土高原鹽堿土壤, 能夠產生耐鹽相關的相容性溶質四氫嘧啶,。為了研究四氫嘧啶的功能, 克隆了DTY1 菌株四氫嘧啶合成基因簇ectABC,。ectA、ectB 和ectC 分別編碼169,、428 和132 個氨基酸的肽鏈, 分別與B.halodurans C-125 中的二氨基丁酸乙?;D移酶(EctA),、二氨基丁酸氨基轉移酶(EctB)、四氫嘧啶合成酶(EctC)同源性達59%,、81%和81%,。將攜帶該基因簇的4.0 kb 片段轉入蠟質芽孢桿菌B. cereus Z后, 芽孢桿菌的耐鹽度顯著提高。HPLC 檢測發(fā)現(xiàn), 在1.0% NaCl 濃度下, 轉化菌B. cereus Z-E 菌株生成70.1 mg/g 四氫嘧啶, 而在5.0%的NaCl 濃度下四氫嘧啶的產量高達118.6 mg/g, 顯著高于B. alcalophilus DTY1 的四氫嘧啶產量,。而且隨著鹽濃度的提高, 四氫嘧啶的合成量也隨之提高,。由此證明四氫嘧啶參與中度嗜鹽菌重要的滲透調節(jié), ectABC 的表達受鹽誘導,。
關鍵詞: 四氫嘧啶, Bacillus alcalophilus, 中度嗜鹽菌
Cloning and Characterization of ectABC Cluster from Bacillus alcalophilus DTY1
Wei Zhang1,2, Hailei Wei3, Hongwen Gao2, and Guohe Huang1
1 Energy and Environmental Research Center, North China Electric Power University, Beijing 102206, China
2 Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100094, China
3 Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
Abstract: Bacillus alcalophilus DTY1, one moderate halophytic bacterium isolated from saline soil in Loess Plateau of China, was characterized with efficient production of ectoine. In this study, the gene cluster ectABC taking in charge of biosynthesizing ectoine was cloned from the genomic library of strain DTY1. Nucleotide sequencing indicated that ectA, ectB and ectC were predicted to encode peptides of 169, 428 and 132 amino acids, respectively. The deduced amino acid sequences of EctA, EctB and EctC share 59%, 81% and 81% identity to 2,4-diaminobutyric acid acetyltransferase, 2,4-diaminobutyric acid transaminase and ectoine synthase of B. halodurans C-125, respectively. A fragment containing ectABC genes was introduced into B. cereus Z, which made the transgenic Z cells increased tolerance to salt, remarkably. HPLC analysis of ectoine in the transgenic Z cells revealed that 70.1 mg/g ectoine was detected in 1.0% NaCl medium and 118.6 mg/g ectoine in 5.0% NaCl medium. Furthermore, as the concentration of salt increased, transgenic Z cells accumulated more ectoine. These results suggest that ectoine is an important facet in B. alcalophilus DTY1 to high-osmolarity surroundings, and the expression of ectABC is induced by salt strength.
Keywords: ectoine, Bacillus alcalophilus, moderate halophytic bacteria
全文下載:中度嗜鹽菌四氫嘧啶合成基因的克隆與功能分析
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