Wang Ke-Chuan, Huang Chih-Hung, Ding Shih-Min, Chen Ching-Kuo, Fang Hsu-Wei, Huang Ming-Te, Fang Shiuh-Bin
Division of Pediatric Gastroenterology and Hepatology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical UniversityTaipei, Taiwan; Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical UniversityTaipei, Taiwan.
Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of Technology Taipei, Taiwan.
Front Microbiol. 2016 Oct 10;7:1614. doi: 10.3389/fmicb.2016.01614. eCollection 2016.
The gene of serovar Typhimurium (. Typhimurium) regulates bacterial growth at different temperatures and mice survival after infection. However, the role of in bacterial colonization and host immunity remains unknown. We infected human LS174T, Caco-2, HeLa, and THP-1 cells with . Typhimurium wild-type SL1344, its mutant, and its complemented strain. Bacterial colonization and internalization in the four cell lines significantly reduced on depletion. Post-infection production of interleukin-8 and human β-defensin-3 in LS174T cells significantly reduced because of deleted in . Typhimurium. The phenotype of C mutant exhibited few and short flagella, fimbriae on the cell surface, enhanced biofilm formation, upregulated type-1 fimbriae expression, and reduced bacterial motility. Type-1 fimbriae, flagella, SPI-1, and SPI-2 gene expression was quantified using real-time PCR. The data show that deletion of upregulated and expression and downregulated , and expression. Furthermore, thin-layer chromatography and high-performance liquid chromatography revealed the absence of menaquinone in the mutant, thus validating the importance of in the bacterial electron transport chain. Therefore, YqiC can negatively regulate FimZ for type-1 fimbriae expression and manipulate the functions of its downstream virulence factors including flagella, SPI-1, and SPI-2 effectors.
鼠伤寒沙门氏菌血清型（.Typhimurium）的基因调节细菌在不同温度下的生长以及感染后小鼠的存活情况。然而，其在细菌定植和宿主免疫中的作用仍不清楚。我们用鼠伤寒沙门氏菌野生型SL1344、其突变体及其互补菌株感染人LS174T、Caco-2、HeLa和THP-1细胞。在缺失时，这四种细胞系中的细菌定植和内化显著减少。由于鼠伤寒沙门氏菌中缺失，感染后LS174T细胞中白细胞介素-8和人β-防御素-3的产生显著减少。C突变体的表型表现为鞭毛少且短、细胞表面有菌毛、生物膜形成增强、1型菌毛表达上调以及细菌运动性降低。使用实时PCR对1型菌毛、鞭毛、SPI-1和SPI-2基因表达进行定量。数据表明，缺失会上调和表达，下调和表达。此外，薄层色谱和高效液相色谱显示突变体中不存在甲基萘醌，从而证实了在细菌电子传递链中的重要性。因此，YqiC可以负向调节1型菌毛表达的FimZ，并操纵其下游毒力因子包括鞭毛、SPI-1和SPI-2效应器的功能。
