Project description:We identified miRNAs differentially regulated upon Salmonella infection by comparative deep-sequencing analysis of cDNA libraries prepared from the small RNA population (10–29 nt) of HeLa cells infected with Salmonella (20 hpi) and mock-treated cells. Considering that at a MOI of 25 Salmonella is internalized in only 10-15% of the HeLa cells, we separated the fraction of cells which had internalized Salmonella (Salmonella+) from the bystander fraction (Salmonella-) by fluorescence-activated cell sorting (FACS), and extended the analysis of miRNA changes to these samples. Interestingly, we observed that Salmonella infection induces a significant decrease in the expression of all the detected members of the miR-15 family
Project description:To have a global picture of the miRNAs regulated upon Salmonella infection, we assessed small RNA changes, by RNA-sequencing, of HeLa cells infected with Salmonella Typhimurium compared with mock-treated cells . In addtion to the total population, we evaluated miRNA expression in the fraction of HeLa cells with internalized bacteria (Salmonella-positive), as well as in bystander cells, separated by fluorescence activated cell sorting (FACS)
Project description:To have a global picture of the miRNAs regulated upon treatement with secretome of Salmonella infected cells, we assessed small RNA changes, by RNA-sequencing, of HeLa cells treated with sectretome of Salmonella infected cells or mock-treated cells
Project description:OmpR is a DNA binding protein belonging to the OmpR/EnvZ two component system. This system is known to sense changes in osmolarity in Escherichia coli. Recently, OmpR in Salmonella enterica serovar Typhimurium was found to be activated by acidic pH and DNA relaxation. In this study, ChIP-on-chip was employed to ascertain the genome-wide distribution of OmpR in Salmonella Typhimurium and Escherichia coli in acidic and neutral pH. In addition we investigated the affect of DNA relaxation on OmpR binding in Salmonella Typhimurium.
Project description:HilD is a regulator of Salmonella pathogenicity island 1 (SPI-1) virulence genes in Salmonella enterica serovar Typhimurium. To identify novel HilD-regulated genes, we mapped the genome-wide association of HilD in S. Typhimurium under SPI-1-inducing conditions (high salt, low aeration) using ChIP-seq. HilD was C-terminally tagged with 3 FLAG tags in strain 14028s.
Project description:Salmonella is an important enteric pathogen that causes a spectrum of diseases varying from mild gastroenteritis to life threatening typhoid fever. Salmonella does not have lac operon. However, E. Coli, Salmonella’s close relative, has lac operon. Being an enteric pathogen like E. coli, Salmonella will also benefit from lac operon. Then, why Salmonella has lost lac operon?. To address this question, lacI, an important component of lac operon was expressed in Salmonella via pTrc99A plasmid. As a control, pTrc99A without lacI was also expressed in Salmonella. The effect of LacI on the transcription profile of Salmonella was analyzed using microarray technique.
Project description:Xenophagy, also known as antibacterial autophagy, is a process of capturing and eliminating cytosolic pathogens, like Salmonella. Salmonella is the best-studied model organism for xenophagy. We present a Petri net model of Salmonella xenophagy in epithelial cells. The model is based on functional information derived from literature data and contains all known processes of Salmonella xenophagy in epithelial. The model comprises the molecular mechanism of galectin-8-dependent and ubiquitin-dependent autophagy, including regulatory processes, like nutrient-dependent regulation of autophagy and TBK1-dependent activation of the autophagy receptor, OPTN. To model the activation of TBK1, we proposed a mechanism of TBK1 activation, suggesting a spatial and temporal regulation of this process. The Petri net is connected, covered by T-invariants, and each T-invariant has a meaningful biological interpretation. We checked the model structure for consistencies and correctness. We found 16 basic functional modules, which describe different pathways of the autophagic capturing of Salmonella and reflect the basic dynamics of the system. The PN model of Salmonella xenophagy comprises 61 places, including nine logical places, and 69 transitions connected by 184 arcs.
Project description:Purpose: Searching for sRNAs in Salmonella pullorum by RNA sequencing and exploring their functions.Methods: High-throughput sequencing of RNA extracted from Salmonella pullorum under normal growth conditions to detect newly discovered sRNAs, followed by experiments to verify their functions.Results: The proportion of Clean Reads of this sequencing was >65%, and the base Q30s were all above 85%, indicating that the sequencing quality is good and can be used for subsequent analysis. The sRNAscanner software predicted that 148 new sRNAs might exist on the reference genome of Salmonella fowl dysentery, and the reads obtained from sequencing were compared to the genome, and it was found that 110 out of the 148 newly predicted sRNAs could be detected.Conclusions: sRNAs are widely found in bacteria and are involved in many physiological processes. In this study, we detected new sRNAs in Salmonella pullorum by RNA-seq, which lays the foundation for the subsequent investigation of the regulatory functions of sRNAs in bacteria.
Project description:AbuOun2009 - Genome-scale metabolic network
of Salmonella typhimurium (iMA945)
This model is described in the article:
Genome scale reconstruction
of a Salmonella metabolic model: comparison of similarity and
differences with a commensal Escherichia coli strain.
AbuOun M, Suthers PF, Jones GI,
Carter BR, Saunders MP, Maranas CD, Woodward MJ, Anjum MF.
J. Biol. Chem. 2009 Oct; 284(43):
29480-29488
Abstract:
Salmonella are closely related to commensal Escherichia coli
but have gained virulence factors enabling them to behave as
enteric pathogens. Less well studied are the similarities and
differences that exist between the metabolic properties of
these organisms that may contribute toward niche adaptation of
Salmonella pathogens. To address this, we have constructed a
genome scale Salmonella metabolic model (iMA945). The model
comprises 945 open reading frames or genes, 1964 reactions, and
1036 metabolites. There was significant overlap with genes
present in E. coli MG1655 model iAF1260. In silico growth
predictions were simulated using the model on different carbon,
nitrogen, phosphorous, and sulfur sources. These were compared
with substrate utilization data gathered from high throughput
phenotyping microarrays revealing good agreement. Of the
compounds tested, the majority were utilizable by both
Salmonella and E. coli. Nevertheless a number of differences
were identified both between Salmonella and E. coli and also
within the Salmonella strains included. These differences
provide valuable insight into differences between a commensal
and a closely related pathogen and within different pathogenic
strains opening new avenues for future explorations.
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MODEL1507180009.
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Project description:Salmonella spp. biofilms have been implicated in persistence in the environment and plant surfaces. In addition, Salmonella is able to form biofilms on the surface on cholesterol gallstones. The ability of Salmonella spp. on these surfaces is superior to biofilm formation on surfaces on glass or plastic. Thus, we hypothesized that Salmonella gene expression is specific during biofilm development on cholesterol surfaces.