Project description:Global transcriptional responses of shigella flexneri to RNA poly merase inhibitor We used two drugs with two concentration. At each concentration, there 3 time points.
Project description:Transcriptional program of a WT and ipaD strain of Shigella flexneri modeling the off- and on-state of the T3SA in vitro were compared by RNA-Seq
Project description:To explore what important role of PhoPQ TCS plays in Shigella virulence, the Agilent microarray technologies was used to compare the transcriptional profiles of Shigella flexneri 2a 301 and △phoPQ mutant strains at middle-log phase (6 h) or early-stationary phase (10 h) under LB growth conditions.
Project description:We evaluated the transcriptome changes induced by infection of Hela 229 cells with Shigella flexneri. The sample set consists of a control (mock), total population of infected sample and infected sample sorted into Shigella positive and Shigella negative population.
Project description:Shigella flexneri is historically regarded as the primary agent of bacillary dysentery, yet the closely-related Shigella sonnei is replacing S. flexneri, especially in developing countries. The underlying reasons for this dramatic shift are mostly unknown. Using a zebrafish (Danio rerio) model of Shigella infection, we discover that S. sonnei is more virulent than S. flexneri in vivo. Whole animal dual-RNAseq and testing of bacterial mutants suggest that S. sonnei virulence depends on its O-antigen oligosaccharide (which is unique among Shigella species). We show in vivo using zebrafish and ex vivo using human neutrophils that S. sonnei O-antigen can mediate neutrophil tolerance. Consistent with this, we demonstrate that O-antigen enables S. sonnei to resist phagolysosome acidification and promotes neutrophil cell death. Chemical inhibition or promotion of phagolysosome maturation respectively decreases and increases neutrophil control of S. sonnei and zebrafish survival. Strikingly, larvae primed with a sublethal dose of S. sonnei are protected against a secondary lethal dose of S. sonnei in an O-antigen-dependent manner, indicating that exposure to O-antigen can train the innate immune system against S. sonnei. Collectively, these findings reveal O-antigen as an important therapeutic target against bacillary dysentery, and may explain the rapidly increasing S. sonnei burden in developing countries.
Project description:In most eukaryotes and bacteria, queuosine (Q) replaces the guanosine at the wobble position of tRNAs harboring a GUN anticodon. To faithfully detect Q-modification in RNAs from Schizosaccharomyces pombe and Shigella flexneri, Q-MaP-Seq was established and applied to tRNAs from S. pombe WT (AEP1) cells and Shigella flexneri WT cells and tgt∆ cells. Q-modification of in vitro-transcribed RNAs and RNAs isolated from S. pombe and S. flexneri followed by reverse transcription using the RT-active DNA polymerase variant RT-KTq I614Y and sequencing of unmodified compared to modified RNAs allowed identification of Q-sites within tRNAs.
Project description:To find the alterations of expression profiles of shigella flexneri, we performed DNA chip analysis and proteomic analysis at the same time.
Project description:Berberine is a natural isoquinoline alkaloid found in Chinese medicinal herbs which is active against a variety of microbial infections. To examine the potential effects of berberine on Shigella flexneri, a whole-genome DNA microarray was constructed and transcriptome analysis of the cellular responses of S.flexneri when exposed to Berberine Chloride (BC) was performed.
Project description:This experiment was designed to identify IFNg-regulated, IRF1-dependent genes during infection with the intracellular pathogen Shigella flexneri. WT and Irf1-/- MEFs were stimulated for 18 hours with IFNg or left unstimulated; all of the cells were subsequently infected for 6 hours with S. flexneri prior to harvest of total RNA.
Project description:The invasive bacteria recognition by host cells through autophagy is a key factor for determining bacterial infection. Enteroinvasive Escherichia coli (EIEC) express a protein IcsB, which in Shigella, is known for inactivating the bacterial degradation process. Once EIEC showed less expression of icsB when compared to S. flexneri, we proposed to investigate the autophagy caused by EIEC infection. Our results showed that IcsB protein is an important virulence factor in EIEC because it causes a camouflage of the bacteria in the eukaryotic cell. When there is low or none expression of the protein, the cell recognition of the invasive bacteria is high, decreasing the bacteria dissemination. This found confirms the importance of the gene transcription and the sequence, since the strain E. coli SM124/13, complemented with icsB from Shigella, showed higher dissemination efficiency inside of the host cell. Additionally, our results revealed that eukaryotic cell infected by EIEC or Shigella flexneri showed distinguish responses. In EIEC infection, the autophagy was activated in human cells, but not in a conventional mode. Our hypothesis is that EIEC is recognized by autophagy, being an important cell process for bacterial recognition.