College of Animal Science and Technology, Jilin Agricultural University, Changchun, China.
Ann N Y Acad Sci. 2020 Apr;1465(1):146-160. doi: 10.1111/nyas.14265. Epub 2019 Oct 30.
Aeromonas veronii is an important aquatic zoonotic pathogen in humans and animals. In recent years, extracellular proteins from bacteria have been found to be the major pathogenic factors for aquatic animals. The aim of this study was to systematically analyze the extracellular proteins of nine sources of A. veronii and the effects of hisJ on virulence. We screened only the common proteins from nine different sources of A. veronii by liquid chromatography-tandem mass spectrometry and identified the gene hisJ. We then constructed ΔhisJ (deleted) and C-hisJ (complemented) variants of A. veronii TH0426 to assess the biological function of hisJ. While the ΔhisJ strain did not show altered growth (P > 0.05), we observed that it had reduced colony formation and biofilm formation and reduced adhesion to and invasion of epithelioma papulosum cyprini cells by 2.0-, 1.9-, and 10.8-fold, respectively. Additionally, infection experiments on zebrafish and mouse infection experiments showed that the virulence of the ΔhisJ strain was decreased by 865-fold (P < 0.001) compared with the wild-type strain; virulence of the complemented C-hisJ strain was reduced only 2.8-fold. Furthermore, in the context of hisJ deletion, flagella of A. veronii TH0426 were easily detached and the expression of virulence genes was downregulated. A persistence test (of bacterial colonies in crucian carp) showed that the number of bacteria in the immune organs of the ΔhisJ-infected group was lower than that in the wild-type-infected group. Overall, these results show that hisJ affects flagellar shedding, virulence, biofilm formation, adhesion, and invasion of A. veronii TH0426, and that hisJ is closely associated with virulence and plays a crucial role in its pathogenicity of A. veronii TH0426.
维氏气单胞菌是一种重要的水生动物人畜共患病病原体。近年来，人们发现细菌的细胞外蛋白是水生动物的主要致病因素。本研究旨在系统分析 9 株维氏气单胞菌的细胞外蛋白，并研究 hisJ 对毒力的影响。我们仅通过液相色谱-串联质谱法从 9 种不同来源的维氏气单胞菌中筛选共同蛋白，并鉴定了 hisJ 基因。然后，我们构建了 A. veronii TH0426 的ΔhisJ（缺失）和 C-hisJ（互补）变体，以评估 hisJ 的生物学功能。虽然ΔhisJ 株的生长没有改变（P > 0.05），但我们观察到其菌落形成、生物膜形成和对鲤鱼上皮瘤细胞的黏附和侵袭能力分别降低了 2.0、1.9 和 10.8 倍。此外，斑马鱼感染实验和小鼠感染实验表明，与野生型菌株相比，ΔhisJ 菌株的毒力降低了 865 倍（P < 0.001）；而互补 C-hisJ 菌株的毒力仅降低了 2.8 倍。此外，在 hisJ 缺失的情况下，维氏气单胞菌 TH0426 的鞭毛很容易脱落，毒力基因的表达下调。在细菌在鲫鱼中持续存在的试验（bacterial persistence test）中显示，ΔhisJ 感染组免疫器官中的细菌数量低于野生型感染组。总体而言，这些结果表明 hisJ 影响维氏气单胞菌 TH0426 的鞭毛脱落、毒力、生物膜形成、黏附和侵袭，并且 hisJ 与毒力密切相关，在维氏气单胞菌 TH0426 的致病性中发挥关键作用。
