单核细胞增生李斯特菌(L.单核细胞增多症)是一种食源性病原体,可引起人类和其他动物的李斯特菌病。具有LPXTG基序的表面蛋白在单核细胞增生李斯特菌的毒力中具有重要作用。Lmo0159是一种这样的蛋白质,但对它在单核细胞增生李斯特菌毒力中的作用知之甚少,运动性,和生物膜的形成。这里,我们构建并表征了lmo0159的缺失突变体(Δlmo0159)。我们不仅分析了生物膜形成的能力,运动性,附件,和不同细胞类型的细胞内生长,还有LD50;小鼠肝脏中的细菌负荷,脾,脾和大脑;毒力基因的表达;以及攻击后小鼠的存活时间。结果表明,通过显微镜检查,Δlmo0159菌株的生物膜交联密度低于WT。生物膜形成和毒力基因的表达在生物膜状态下也降低。随后,Δlmo0159在培养基中的生长和运动增强。相反,单核细胞增生李斯特菌的生长和运动性在细胞和小鼠水平上都被Δlmo0159减弱。在细胞层面,Δlmo0159减少斑块大小;加速划痕愈合;并减弱粘连的效率,入侵,和猪肠道上皮细胞(SIEC)的细胞内增殖,RAW264.7,小鼠脑微血管内皮细胞(mBMEC),和人脑微血管内皮细胞(hCMEC/D3)。毒力基因的表达也受到抑制。在鼠标级别,Δlmo0159菌株的LD50是WT菌株的100.97倍。Δlmo0159菌株在肝脏和脾脏中的细菌负荷低于WT菌株。在腹腔感染的小鼠模型中,lmo0159基因的缺失显著延长了小鼠的存活时间,表明lmo0159缺失突变体也表现出降低的毒力。因此,我们的研究确定lmo0159是单核细胞增生李斯特菌LPXTG蛋白中的一种新型毒力因子。
Listeria monocytogenes (L. monocytogenes) is a foodborne pathogen that causes listeriosis in humans and other animals. Surface proteins with the LPXTG motif have important roles in the virulence of L. monocytogenes. Lmo0159 is one such protein, but little is known about its role in L. monocytogenes virulence, motility, and biofilm formation. Here, we constructed and characterized a deletion mutant of lmo0159 (∆lmo0159). We analyzed not only the capacity of biofilm formation, motility, attachment, and intracellular growth in different cell types but also LD50; bacterial load in mice\'s liver, spleen, and brain; expression of virulence genes; and survival time of mice after challenge. The results showed that the cross-linking density of the biofilm of ∆lmo0159 strain was lower than that of WT by microscopic examination. The expression of biofilm-formation and virulence genes also decreased in the biofilm state. Subsequently, the growth and motility of ∆lmo0159 in the culture medium were enhanced. Conversely, the growth and motility of L. monocytogenes were attenuated by ∆lmo0159 at both the cellular and mouse levels. At the cellular level, ∆lmo0159 reduced plaque size; accelerated scratch healing; and attenuated the efficiency of adhesion, invasion, and intracellular proliferation in swine intestinal epithelial cells (SIEC), RAW264.7, mouse-brain microvascular endothelial cells (mBMEC), and human-brain microvascular endothelial cells (hCMEC/D3). The expression of virulence genes was also inhibited. At the mouse level, the LD50 of the ∆lmo0159 strain was 100.97 times higher than that of the WT strain. The bacterial load of the ∆lmo0159 strain in the liver and spleen was lower than that of the WT strain. In a mouse model of intraperitoneal infection, the deletion of the lmo0159 gene significantly prolonged the survival time of the mice, suggesting that the lmo0159 deletion mutant also exhibited reduced virulence. Thus, our study identified lmo0159 as a novel virulence factor among L. monocytogenes LPXTG proteins.