嗜水气单胞菌脂肪酸生物合成途径相关蛋白的耐药性

嗜水气单胞菌Aeromonas hydrophila是一种广泛存在于水体与土壤的人-畜-鱼共患病原菌。本课题组前期研究发现生物被膜状态下嗜水气单胞菌在抗生素金霉素的胁迫下,脂肪酸生物合成途径中相关蛋白表达上升,但具体特性与功能尚不明确。为进一步探究这些蛋白在抗生素胁迫下的变化规律与功能,设计引物克隆乙酰辅酶A羧化酶羧基转移酶α亚基(AccA)、乙酰辅酶A羧化酶羧基转移酶β亚基(AccD)、酰基载体蛋白质合成酶(FabB)以及丙二酸单酰辅酶A酰基载体蛋白酰基转移酶(FabD)。通过比较各高表达菌株在金霉素作用下的生存率,来分析相关蛋白的耐药特性。结果表明,高表达AccD、FabB和FabD蛋白能够显著提高细菌在抗生素胁迫下的生存率,而高表达AccA蛋白则只在前期提高细菌存活率。此研究揭示脂肪酸生物合成途径相关蛋白在细菌的耐药过程中起重要作用,也为后续研究嗜水气单胞菌的耐药机制提供了实验依据。

Antibiotic-resistance Related to Proteins Associated with Fatty Acid Biosynthesis in Aeromonas hydrophila

Widely exists in water and soil,Aeromonas hydrophila is a commonpathogen for human,livestock and fish.It was previously observed in our lab that the expression of the proteins associated with the fatty acid biosynthesis in A.hydrophilarose under the stress of chlortetracycline.But the specific properties and functions were not understood.Therefore,this study was designed to clone and express those potentially important proteins,including acetyl-coenzyme A carboxylase carboxyl transferase subunit alpha (AccA),acetyl-coenzyme A carboxylase carboxyl transferase subunit beta (AccD),3-oxoacyl-[acyl-carrier-protein] synthase I (FabB),and malonyl coAacyl carrier protein transacylase (FabD) for further investigation.By comparing the survival rates of high-expression strains of A.hydrophila under chlortetracycline stress,the drug-resistance relating to the proteinsin the fatty acid biosynthesispathway was analyzed.The results showed that the high-expression proteins,AccD,FabB and FabD,could indeed significantly increase the survival rate of the pathogen under chlortetracycline stress,while AccA did so only during the initial stage.Consequently,a critical role of these proteins involving the bacterial drug-resistance was clearly demonstrated.With the finding,further study to unveil the mechanism of antibiotic-resistance of the pathogen is in order.