Kang Meiqin, Cai Xuexue, Tan Weijun, Duan Feifei, Zhao Dan, Duan Feifei, Zhao Dan, Pan Zhiming, Yin Yuelan, Jiao Xin'an
Wei Sheng Wu Xue Bao. 2015 Apr 4;55(4):433-9.
Gram-positive brevibacterium Listeria monocytogenes (Lm) is an important zoonotic foodborne pathogen, engaged in both saprophytism and parasitism. It could adapt, survive and display pathogenicity under different environmental stress challenges, which is associated with the regulatory network consisting of regulating factors. The biological characterizations of regulator hfq was evaluated in this study.
hfq deleted serovar 1/2 a strain EGDe was constructed with homologous recombination, the biological characteristics of the mutant strain was compared with its parental strain.
The growth of EGDe delta hfq was significantly inhibited under cold temperature (P < 0.05), salt medium containing 7% NaCl and the medium containing 4.5% ethanol. The ability of biofilm formation of the mutant strain in BactoTM Brain Heart Infusion (BHI) was reduced significantly (P < 0.05); notably, the invasion rate to Caco-2 cell lines was obviously reduced. Infection capacity of EGDe delta hfq to BALB /c mice decreased and the LDD was 6 times higher than EGDe.
Hfq protein of Listeria monocytogenes plays an important role in regulating bacterial virulence, biofilm formation and stress response. This deletion strain provided material to further study the function of Hfq and provides the possibilities to elucidate the mechanisms of Lm in resisting the stress and paves ways to the development of novel strategies for the prevention and control of Lm infections.
革兰氏阳性短杆菌单核细胞增生李斯特菌（Lm）是一种重要的人畜共患食源性病原体，兼具腐生和寄生特性。它能够在不同的环境应激挑战下适应、存活并表现出致病性，这与由调控因子组成的调控网络有关。本研究评估了调控因子hfq的生物学特性。
利用同源重组构建hfq缺失的1/2a血清型菌株EGDe，将突变株的生物学特性与其亲本菌株进行比较。
EGDeΔhfq在低温（P<0.05）、含7%NaCl的盐培养基和含4.5%乙醇的培养基中生长受到显著抑制。突变株在脑心浸液（BHI）中形成生物膜的能力显著降低（P<0.05）；值得注意的是，其对Caco-2细胞系的侵袭率明显降低。EGDeΔhfq对BALB/c小鼠的感染能力下降，半数致死剂量比EGDe高6倍。
单核细胞增生李斯特菌的Hfq蛋白在调节细菌毒力、生物膜形成和应激反应中起重要作用。该缺失株为进一步研究Hfq的功能提供了材料，为阐明Lm抵抗应激的机制提供了可能，为开发预防和控制Lm感染的新策略铺平了道路。
