wzzE不影响禽致病性大肠杆菌雏鸭分离株LPS的表型

wzzE does not affect lipopolysaccharide phenotype of avian pathogenic Escherichia coli from clinical ducking

摘要:

[目的] wzz参与很多革兰氏阴性菌O抗原的合成,并对细菌的致病性具有调控作用。在禽致病性大肠杆菌(Avian pathogenic Escherichia coli, APEC)中,存在Wzz蛋白超家族基因wzzE,目前尚未开展该基因对APEC脂多糖(LPS)的合成及致病作用研究,因此本研究开展了wzzE对APEC LPS合成以及生物学特性影响的研究。[方法] 通过构建APEC DE17株的wzzE缺失株,开展对野生型和缺失株的LD₅₀、黏附与入侵DF-1细胞、脂多糖表型及内毒素毒价等相关生物学特性的影响研究。[结果] 结果表明,缺失wzzE的APEC,不影响细菌的生长特性。野生型、缺失株及回复株的LPS表型无明显差异。DE17ΔwzzE与DE17的黏附与入侵结果无显著差异。血清型鉴定结果表明,缺失wzzE,不影响细菌的血清型。内毒素毒力检测结果DE17、DE17ΔwzzE及CΔwzzE内毒素的毒价一致,为4×10⁵ EU/mg。对7日龄樱桃谷鸭进行攻毒,测定各菌株的LD₅₀,结果表明,与野生型相比,DE17ΔwzzE缺失株毒力下降了10倍。[结论] wzzE缺失对LPS的表型无显著影响,但wzzE参与APEC的致病过程,然而wzzE 对APEC毒力的调控机制仍有待进一步研究。

Abstract:

[Objective] wzz is involved in the synthesis of O antigen and plays a role in virulence in many gram-negative bacteria. However, the function of wzzE in avian pathogenic Escherichia coli (APEC) is unclear. The aim of this study is to elucidate the role of wzzE in the synthesis of LPS and virulence. [Methods] Mutant strain with wzzE deletation was constructed. Biological characteristics of the wild and mutant strains, such as LD₅₀, adherence and invasion to DF-1 cells, phenotype of LPS and endotoxin titer, were detected. [Results] There was no significant difference in growth, adherence and invasion to DF-1 cells, serotype and the endotoxin titer between the wide strain and the mutant. However, compared with the wild-type strain, the virulence of DE17ΔwzzE had dropped by 10 times. [Conclusion] wzzE is not involved in the synthesis of LPS in DE17, but participates in the pathogenic process of APEC. However, the mechanism of wzzE in APEC virulence needs to be studied in the future.