rBTI的制备及其对果蝇寿命的影响

Preparation of Recombinant Buckwheat Trypsin Inhibitor and Its Effect on the Lifespan of Drosophila melanogaster

构建含荞麦胰蛋白酶抑制剂(rBTI)表达质粒pExSecI-BTI的工程菌,在100 L发酵罐中放大发酵,发酵产物经热处理及离子交换层析纯化后,获得rBTI产品,其纯度达到95%以上。用含不同质量浓度rBTI(0、20、50μg/mL)的培养基饲养果蝇,并分别检测果蝇的最高寿命,平均寿命和半数死亡时间等。初步研究rBTI对果蝇寿命的影响。结果显示,rBTI能够显著延长果蝇的寿命。在实验剂量范围内,果蝇的寿命与rBTI质量浓度呈现正相关。抗氧化酶活性检测发现,实验组果蝇体内的SOD和CAT活性均显著升高。rBTI延缓果蝇衰老的作用可能是通过刺激机体的氧化应激能力来实现的。

E.coli BL21（DE3） containing recombinant plasmid pExSecI buckwheat trypsin inhibitor （BTI） was constructed by gene cloning,and was cultured in a 100 L fermentor for large-scale fermentation.The fermentation products were purified by heat treatment and ion exchange chromatography.The purity of recombinant BTI obtained was greater than 95％ after a series of optimization steps.Then fi-uit flies were fed with a medium containing different concentrations of rBTI （0,20,50 μg/mL）.The maximum lifespan,average lifespan and lethal dose-50 time were tested,respectively.The effect of the purified rBTI on he fruit fly＇s lifespan was studied.The results showed that rBTI significantly extended the lifespan of fruit fly in a dose-dependent way within the range of experimental doses.At the same time,the activities of superoxide dismutase （SOD） and catalase （CAT） were found to be significantly increased in the fruit flies of the experimental group.The preliminary studies indicate that the anti-aging effect of rBTI on fruit flies may be achieved by increasing its anti-oxidative stress ability.