嗜水气单胞菌非核糖体肽合成酶基因功能研究

非核糖体肽是微生物体内一类具有天然生物活性的次生代谢物,由非核糖体肽合成酶催化生成。而AHA2474和AHA2476是嗜水气单胞菌ATCC7966中两个编码非核糖体肽合成酶的基因。利用同源重组技术分别构建了AHA2474、AHA2476基因缺失株,并对其生理特性进行测定。结果表明,与野生株相比,缺失株的溶血性和胞外蛋白酶活性均显著增强,而产铁能力明显减弱;在缺铁条件下,缺失株的生长能力较弱,补充铁离子后又能恢复生长。同时在过氧化氢应激下ΔAHA2474菌株具有更大的耐受性。以上研究结果提示AHA2474和AHA2476基因可能通过影响铁离子动态平衡过程来调控该菌的生理特性,同时也表明非核糖体肽在该菌致病性方面起作用,为探究该菌的致病机制及防治策略提供理论依据。

The Functional Analysis of Non-ribosomal Peptide Synthetase in Aeromonas hydrophila

Non-ribosomal peptides are a class of secondary biological metabolites with natural biological activity in microorganisms,and they are catalyzed by non-ribosomal peptide synthetase.AHA2474 and AHA2476 are two genes encoding non-ribosomal peptide synthetase in Aeromonas hydrophila ATCC7966.In this paper,the deletion strains of AHA2474 and AHA2476 were constructed by homologous recombination technique,and their physiological characteristics were determined.The results showed that the hemolytic and extracellular protease activities of the deletion strains were significantly enhanced,while the iron-producing abilities were significantly reduced,when compared with wild strain.The growths of the mutants decreased in the iron limited medium,but were restored in iron supplementation.Moreover,ΔAHA2474 strain showed more tolerance under hydrogen peroxide stress.Our results indicate that the AHA2474 and AHA2476 genes may regulate the physiological characteristics of the bacteria by affecting the iron ion homeostasis process,suggesting the role of non-ribosomal peptide in bacterial pathogenicity,which provide a theoretical basis for exploring the pathogenic mechanism and prevention strategy.