Journal of Integrative Agriculture

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内膜蛋白TolA促进禽致病性大肠杆菌耐药性、环境适应性、生物被膜形成及毒力

  

  • 修回日期:2025-02-12

Inner membrane protein TolA facilitates the antibiotic resistance, environment adaptability, biofilm formation and virulence of avian pathogenic Escherichia coli

Shuangyang Li1, 2*, Jiangang Hu1*, Chang Liu1, Zizhu Lin1, Haoheng Peng1, Beibei Zhang1, Xinyu Wang1, Weiqi Guo1, Jingjing Qi1, Mingxing Tian1, Yanqing Bao1, Guangdong Zhang1, Yuxiang Shi2#, Shaohui Wang1#   

  1. 1 Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China

    2 College of Life Science and Food Engineering, Hebei University of Engineering, Handan 056001, China

  • Revised:2025-02-12
  • About author: Shuangyang Li, E-mail: lsy12201102@126.com; Jiangang Hu, E-mail: vethjg@163.com; #Correspondence Shaohui Wang, Tel: +86-15821927863, E-mail: shwang@shvri.ac.cn; Yuxiang Shi, Tel: +86-13785085092, E-mail: hbyxshi@126.com * These authors contributed equally to this study.
  • Supported by:

    This work was supported by the National Key Research and Development Program of China (2021YFD1800402), National Natural Science Foundation of China (32172856, 32302881), the Natural Science Foundation of Shanghai (22ZR1476100, 23ZR1476600), the China Postdoctoral Science Foundation (2023M743852), the Shanghai Oriental Talent Plan, and the Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences (CAAS-ASTIP-2021-SHVRI-07).

摘要:

禽致病性大肠杆菌(Avian pathogenic Escherichia coli, APEC)可引起禽大肠杆菌病,给养禽业造成重大经济损失。细胞膜是细菌赖以生存的重要结构,其对细菌的环境适应毒力至关重要。Tol-pal系统是革兰阴性菌中由五种蛋白组成的动态复合体,其中内膜蛋白TolA有助于维持细胞膜的完整性。然而,内膜蛋白TolA在APEC环境适应性和致病性中的作用尚不完全清楚。因此,本研究构建APEC菌株tolA基因缺失株和互补株,分析TolAAPEC生物学特性及毒力的影响。结果发现,缺失tolA基因导致APEC形态显著变化鞭毛减少运动性降低外膜囊泡产量增加tolA基因缺失株的细胞膜完整性受损,从而降低其对抗生素耐受性和环境压力适应性通过荧光定量PCR分析发现tolA基因缺失引起生物被膜相关基因及VI型分泌系统基因转录水平下调,导致生物被膜形成能力和细菌间竞争能力均下降。与野生株和互补株相比,tolA基因缺失株的抗血清杀菌能力、细胞黏附入侵能力胞内存活能力、体内定植能力均显著降低,导致宿主产生较少的炎症及致死率。结果表明,内膜蛋白TolA在APEC的抗生素耐受性、环境适应能力、生物被膜形成及致病性等方面发挥重要作用,为阐明APEC的环境适应性及致病机制提供参考。

Abstract:

Avian pathogenic Escherichia coli (APEC) could cause colibacillosis, which is economically devastating to poultry industries worldwide. The bacterial membrane is critical to its environment adaptability and virulence. The inner membrane protein TolA maintains membrane integrity, but the roles of which in fitness and pathogenesis of APEC are not completely understood. Thus, the tolA gene mutant and complemented strains of APEC were constructed and characterized. We found that mutant strain ΔtolA was damaged in inner and outer membranes, and showed altered morphology, impaired flagella production, reduced motility, increased outer membrane vesicles (OMVs) production, decreased resistance to antibiotics and environmental stress. Deletion of tolA gene resulted in a significant decrease in biofilm formation and interbacterial competition, due to the downregulated expression of biofilm-associated genes and type VI secretion system (T6SS) genes, respectively. In addition, the mutant strain exhibited diminished serum bactericidal resistance, reduced cell infection capacity, decreased intracellular survival, consequently, leading to attenuated bacterial survival and virulence in mice. Compared with the wild-type and complemented strains, mutant strain induced less expression of inflammatory cytokine interleukin 1 beta (IL-1β) in HD-11 macrophages, consistent with the pathological damage in mice. In conclusion, inner membrane protein TolA contributed to the antibiotic resistance, environment adaptability, biofilm formation and virulence of APEC.

Key words: Avian pathogenic Escherichia coli , TolA , Membrane integrity ,  , Biofilm ,  , Virulence