水库鲮和罗非鱼谷胱甘肽转移酶基因表达量与水中蓝藻含量的关系

Relationship between GST gene expression of mud carp (Cirrhina molitorella) and Nile tilapia(Oreochromis niloticus) and composition of algae in Xiangang Reservoir

采用荧光定量的方法对不同季节广州显岗水库鲮(Cirrhinus molitorella)和尼罗罗非鱼(Oreochro-mis niloticu)肝脏中去毒酶基因谷胱甘肽转移酶GST基因的表达情况,并结合不同季节鱼类摄入蓝藻量进行研究,旨在了解鱼体中GST基因的表达量与水体中蓝藻含量的内在联系。结果表明,4月份水库蓝藻暴发,也是鲮和尼罗罗非鱼摄食产毒蓝藻量最多的月份。GST基因的表达情况是:4月份鲮GST基因表达量比其他月份低,可能与鲮对有毒蓝藻的敏感性和耐受力有关,4月份尼罗罗非鱼GSTA及GSTR2表达量最高;其他月份,鲮GSTT表达量最高,而GSTK表达量较低,尼罗罗非鱼GSTA及GSTR2表达量相对较低。结果表明鲮GSTT在去毒过程中起重要作用,但作为环境检测的生物标记,仅适用于环境中藻毒素较低的情况。尼罗罗非鱼GSTA和GSTR2的表达量与食物中的产毒蓝藻生物量多少成正比,因此,尼罗罗非鱼GSTA及GSTR2可作为环境中藻毒素的生物标记,且尼罗罗非鱼可摄入大量有毒蓝藻,通过GST基因去除有毒蓝藻毒性,可用于生物控藻,改善水质。

To study the relationship and the intrinsic link between the expression of liver GST（glutathione S-transferases） gene in mud carp（Cirrhinus molitorella） and Nile tilapia（Oreochromis niloticus） and the amount of cyanobacteriad,the expression of liver GST gene from the two fishes were analyzed using real-time RT-PCR and the amount of cyanobacteria intake of fish were determined in Xiangang Reservoir in different seasons.The results showed that April was the time that cyanobacteria bloomed,and simultaneously,mud carp and Nile tilapia intake the largest amount of toxic cyanobacteria.The GST genes in mud carp were expressed significantly lower in April than the rest time of the year,which suggested that mud carp may be resistant or tolerant totoxic cyanophyta.Both GSTA and GSTR2 genes in Nile tilapia had the highest expression in April.However,in the other months,the expression of GSTT was significantly high but GSTK was low in mud carp.While GSTA and GSTR2 expressed relatively low in Nile tilapia.It was obvious that GSTT of mud carp played an important role in detoxication process,but as biomarkers for the identification of toxic,it could be used only in low concentration of microcystin.The expression of GSTA and GSTR2 were positively related to the quantity of toxic algae intake in Nile tilapia.Therefore,the expression of GSTA and GSTR2 in Nile tilapia can be used as biomarkers to detect toxic algae.As Nile tilapia can consume large amounts of toxic algae,and its GST gene can detoxifytoxic algae,Nile tilapia was able to be used to biologically control of alga and finally improve water quality.