微囊藻毒素降解酶基因cDNA部分序列的克隆及检测分析

Molecular cloning and detection of partial cDNA sequence of microcystinase gene

微囊藻毒素降解酶(Microcystinase,MlrA)是在自然环境中微囊藻毒素(Microcystin,MC)降解过程中起重要作用的酶。通过PCR方法从水体中扩增MlrA基因cDNA部分序列,序列长342 bp,编码113个氨基酸(GenBank号:FJ972202),PCR方法系统性检测不同季节环境中水体、鱼体MlrA的存在情况。结果表明,克隆的序列与日本学者Saito所公布的Sphingomonassp.MD-1、Y2菌株的MlrA基因同源性高达96%和89%,与挪威Sphingomonas sp.ACM-3962、澳大利亚Sphingopyxis sp.LH21菌株的MlrA基因同源性分别为95%和94%,确定所获为鞘氨醇单胞菌菌株中的MlrA基因cDNA部分序列。同时对不同季节环境水体和部分鱼体MlrA基因的检测时,发现在水华发生的四月及五月,水体和所检测的鱼体中MlrA基因结果显示为阳性,而所检测的其余6个月份的全部水样以及7月和10月检测的鱼样,结果均呈阴性。

Microcystinase plays an important role in the biodegradation of microcystin in physical environment. Partial cDNA sequence of microcystinase （MlrA） gcne from water body was obtained by PCR, which was 342 bp in length and encoded 113 amino acids （GenBank ID： FJ972202）. MlrA was detected in water and fish body in different seasons by PCR methods. Homology of the Mira amino acid sequence was 96% and 89% with the MlrA from Sphingomonas sp. MD-1 and Y2 published by saito in Japanese, and also was 95% and 94% with the MlrA from Sphingomonas sp.ACM-3962 in Norway and Sphingopyxis sp. LH21 in Australia, confirming that the sequences was cloned from Sphingomonas sp.. At the same time, we detected part of the fish and water in some seasons, and found the detection of MlrA gene showed positive in April and May, but that of the water detected in the other 6 months, and the fish detected in June and October showed negative.