Jiangsu Key Laboratory of Zoonosis, Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA of China, Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou 225009, Jiangsu Province, China.
Jiangsu Key Laboratory of Zoonosis, Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, MOA of China, Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonosis, Yangzhou University, 48 East Wenhui Road, Yangzhou 225009, Jiangsu Province, China.
Microbiol Res. 2018 Oct;215:148-154. doi: 10.1016/j.micres.2018.07.001. Epub 2018 Jul 7.
Regulator factor Hfq has been widely detected among both Gram-positive and Gram-negative bacteria; however, its role in Gram-positive bacteria is less well established and varies among species. In Listeria monocytogenes (Lm), an organism able to adapt to a range of environments and live both saprobiotic and parasitic lifestyles, the role of Hfq is not fully understood. Serotype 4b Listeria monocytogenes strains associated with the majority of listeriosis outbreak, while the function of hfq in serotype 4b strains still not referenced. Here, we constructed hfq deletion and reversion mutants of serotype 4b Lm NTSN and analysed the biological characteristics both in vitro and in vivo. The deletion of hfq resulted in a growth deficiency in medium containing 4.5% ethanol or 1% Triton X-100, and the growth of the mutant was significantly reduced at 4 °C. Furthermore, the hfq deletion dramatically decreased biofilm formation in BHI medium and gastric fluid medium, and reduced the invasion and replication rate into the Caco-2BBe cells and RAW264.7 cells. However, complementation restored the wild-type phenotype. Importantly, mouse infection experiments demonstrated that hfq played a more important role in the colonisation and virulence in serotype 4b strain Lm NTSN than in the serotype 1/2a strain Lm EGDe. Taken together, these results demonstrated that hfq is a novel factor associated with biofilm formation, and plays an essential role in the stress response and pathogenisis in serotype 4b strain Lm NTSN. Our data provide the basis for further research into the function of Hfq in serotype 4b Listeria monocytogenes.
调控因子 Hfq 广泛存在于革兰氏阳性菌和革兰氏阴性菌中；然而，其在革兰氏阳性菌中的作用尚未得到充分证实，并且在不同物种之间存在差异。在李斯特菌（Listeria monocytogenes，Lm）中，这种能够适应多种环境并以腐生和寄生两种生活方式生存的生物体，Hfq 的作用尚未完全阐明。与大多数李斯特菌病爆发相关的 4b 型李斯特菌血清型菌株，而 hfq 在 4b 型菌株中的功能尚未被引用。在这里，我们构建了 4b 型李斯特菌 NTSN 的 hfq 缺失和回复突变体，并分析了其在体外和体内的生物学特性。hfq 的缺失导致在含有 4.5%乙醇或 1%Triton X-100 的培养基中生长不良，并且突变体的生长在 4°C 时显著降低。此外，hfq 的缺失显著降低了在 BHI 培养基和胃液培养基中的生物膜形成，并降低了进入 Caco-2BBe 细胞和 RAW264.7 细胞的侵袭和复制率。然而，互补恢复了野生型表型。重要的是，小鼠感染实验表明，hfq 在 4b 型菌株 Lm NTSN 的定植和毒力中比在 1/2a 型菌株 Lm EGDe 中发挥更重要的作用。总之，这些结果表明 hfq 是与生物膜形成相关的新型因子，并在 4b 型菌株 Lm NTSN 的应激反应和发病机制中发挥重要作用。我们的数据为进一步研究 4b 型李斯特菌 Hfq 的功能提供了基础。
