副鸡禽杆菌TonB转座子插入突变株的生物学特性

Biological characteristics of the transposon insertion mutant of TonB in Avibacterium paragallinarum

摘要:

目的 探究生物被膜形成能力减弱的转座子插入突变株对副鸡禽杆菌生物学特性的调控作用。方法 以野生株JZIC-005和转座子突变株Tn-1504 (从突变库中筛选获得，生物被膜形成能力减弱)为研究对象，进行插入位点鉴定及生物学特性分析。结果 PCR验证显示转座子特异性插入副鸡禽杆菌TonB基因中。与野生株相比，突变株Tn-1504的增殖能力未发生显著改变(P>0.05)，但对DF-1细胞的黏附率降低46.57%，侵袭率下降77.61%，细胞毒性减弱34.97%。上述表型差异均具有统计学意义(P<0.01)。结论 本研究证实TonB基因失活可特异性削弱副鸡禽杆菌的宿主黏附、侵袭及毒性特征，为解析该病原致病机制及抗毒力策略开发提供了关键靶点。

Abstract:

Objective To elucidate the virulence-associated biological characteristics of a transposon insertion mutant with impaired biofilm formation of Avibacterium paragallinarum.Methods The wild-type strain JZIC-005 and a biofilm-deficient mutant Tn-1504 (from a pre-established transposon mutant library) were selected for determination of insertion sites biological characterization.Results PCR results demonstrated site-specific transposon integration into TonB of A. paragallinarum. While mutant Tn-1504 exhibited no growth defects compared with the wild-type strain (P>0.05), it demonstrated reductions of 46.57% in adhesion to DF-1 cells and 77.61% in cellular invasion. Cytotoxicity assays revealed a 34.97% reduction of Tn-1504 in inducing host cell damage. All of the above phenotypic differences were statistically significant (P<0.01).Conclusion We demonstrate that inactivation of TonB specifically impairs the adhesion, invasion, and virulence characteristics of A. paragallinarum, providing a key target for analyzing the pathogenic mechanism and developing anti-virulence strategies for this pathogen.