肽酶PepT参与副溶血弧菌的浮游运动和生物被膜形成

Peptidase T is related to swimming motility and biofilm formation of Vibrio parahaemolyticus

摘要:

pepT基因编码一种金属依赖性肽酶T (peptidase T,PepT),能特异性催化三肽N端氨基酸,因此也称为氨肽酶T。研究发现大多数氨肽酶参与细菌蛋白质新陈代谢和调节三肽活性,但关于PepT在细菌毒力及致病性方面的报道较少。[目的]本文选取PepT为研究对象,研究其对副溶血弧菌生物学特性及致病性的影响。[方法]通过构建缺失株ΔpepT和回补株CΔpepT,比较菌株在运动性、生物被膜、环境耐受、细胞毒性等方面的差异。[结果]与野生株相比,ΔpepT缺失株的极性鞭毛转录水平极显著下降,浮游运动能力降低;同时生物被膜形成能力减弱,而细菌群集运动及环境耐受能力无显著差异。此外,缺失pepT基因会导致副溶血弧菌的细胞毒性和小鼠毒力作用显著下降。[结论]pepT基因与副溶血弧菌浮游运动和生物被膜形成能力相关,并且影响其致病性。

Abstract:

The pepT gene of Vibrio parahaemolyticus encodes a metal dependent peptidase T (PepT) that catalyzes the N-terminal amino acid of tripeptides with high specificity,and thus it is also called aminopeptidase T.Studies have found that most aminopeptidases are involved in protein metabolism of bacteria and regulating the activity of tripeptides,but little is known about PepT in bacterial virulence and pathogenicity.[Objective] In this study,PepT was chosen to explore the effect of gene deletion on the biological characteristics and pathogenicity of V.parahaemolyticus.[Methods] The pepT gene deletion mutant ΔpepT and the complementary strain CΔpepT were generated and their differences of various strains in motility,biofilm,environmental tolerance and cytotoxicity were compared.[Results] Compared with the wild-type strain,ΔpepT had significantly decreased transcription level of polar flagella and reduced swimming mobility.Furthermore,the biofilm formation ability of ΔpepT was weakened,but there were not statistically significant in the swarming mobility and environmental tolerance.In addition,the pepT gene deletion resulted in remarkably lowered cytotoxicity and virulence of V.parahaemolyticus in mice.[Conclusion] The pepT gene deletion affects the swimming motility and biofilm formation ability as well as the pathogenicity of V.parahaemolyticus.