Regulation of biofilm formation and cellulose production in Salmonella enterica serovar Typhimurium

该项目旨在研究沙门氏菌生物膜中差异基因的表达和纤维素合成的调节。瑞典斯德哥尔摩的卡罗林斯卡研究所将担任外国主办机构。研究将在微生物学、肿瘤和细胞生物学系的Ute Römling教授小组中进行。该项目涉及一种差异RNA测序方法，该方法将与维尔茨堡分子感染生物学研究所(Jörg Vogel教授)合作进行。鼠伤寒沙门氏菌可以形成生物膜，多细胞结构，具有更强的抗应激能力。生物膜中的主要转录调控因子是CsgD。有趣的是，并不是所有细胞都表达csgD。将使用CsgD-GFP报告菌株在不同条件下研究这种双稳态表达模式。用荧光激活细胞分选法分离CsgD表达细胞和非表达细胞。来自这两个群体的RNA将接受差异RNA测序。这一全球方法将揭示参与生物膜双稳表达的调控sRNA，并进一步深入了解c-di-GMP依赖的CsgD介导的生物膜形成。沙门氏菌在生物膜中形成的细胞外基质的一个成分是纤维素。已知有两个操纵子编码对纤维素生产至关重要的基因。染色体报告融合到参与纤维素生物合成的不同基因将有助于揭示转录和转录后调控。为了确定新的调节子，将进行随机转座子突变。此外，还将研究RNA伴侣Hfq和小调节RNA对纤维素生物合成的重要性。

The project aims at investigating differential gene expression in Salmonella biofilms and regulation of cellulose synthesis. The Karolinska Institute in Stockholm, Sweden will serve as foreign host institution. Research will be performed in the group of Prof. Dr. Ute Römling, Department of Microbiology, Tumor and Cell Biology. The project involves a differential RNA sequencing approach, which will be performed in collaboration at the Institute for Molecular Infection Biology, Würzburg (Prof. Dr. Jörg Vogel).Salmonella typhimurium can form biofilms, multicellular structures with increased stress resistance. The main transcriptional regulator in biofilms is CsgD. Interestingly, not all cells express csgD. This bistable expression pattern will be investigated under different conditions using a CsgD-GFP reporter strain. CsgD expressing and non-expressing cells will be separated by fluorescence activated cell sorting. RNA from both populations will be subjected to differential RNA sequencing. This global approach will reveal regulatory sRNAs involved in bistable expression in biofilms and give further insight into c-di-GMP dependent, CsgD mediated biofilm formation.One component of the extracellular matrix formed by Salmonella in biofilms is cellulose. Two operons are known to encode genes important for cellulose production. Chromosomal reporter fusions to different genes involved in cellulose biosynthesis will shed light on transcriptional and post-transcriptional regulation. To identify novel regulators, random transposon mutagenesis will be performed. Further, the importance of the RNA chaperone Hfq and small regulatory RNAs on biosynthesis of cellulose will be investigated.