Project description:In the two F8 advanced crosses of broiler by Leghorn and broiler by Fayoumi, birds at day 1 were challenged with Salmonella enteritidis (SE). Spleen were collected at day 7 and 8. SE bacterial load in spleen were measured. Based on the bacterial load, birds were divided into high and low SE load groups. Keywords: Salmonella enteritidis challenge
Project description:Investigation of whole genome gene expression level changes in Salmonella enterica serova Enteritidis and Typhimurium under chlorine treatment
Project description:Salmonella enteritidis is suggested to translocate in the small intestine. Previously we identified that prebiotics, fermented in the colon, increased Salmonella translocation in rats, suggesting involvement of the colon in translocation. Effects of Salmonella on colonic gene expression in vivo are largely unknown. The aim of this study was to characterize time dependent Salmonella induced changes of colonic mucosal gene expression in rats using whole genome microarrays. Rats were orally infected with Salmonella enteritidis to mimic a foodbore infection and colonic gene expression was determined at day 1, 3 and 6 post-infection (n=8 per timepoint). Agilent rat whole genome microarray (G4131A Agilent Technologies) were used. Results indicate that colon is clearly a target tissue for Salmonella considering the abundant changes in mucosal gene expression observed. Keywords: Time point infection study, colon mucosa, Rat
Project description:Excisable Genomic Islands (EGIs) are horizontally acquired genetic elements that harbor an array of genes with diverse functions. ROD21 is an EGI found integrated in the chromosome of Salmonella enterica serovar Enteritidis (Salmonella ser. Enteritidis). While this island is known to be involved in the capacity of Salmonella ser. Enteritidis to cross the epithelial barrier and colonize sterile organs, the role for most of ROD21 genes remains unknown, and thus identification of their function is fundamental to understand the impact of this EGI on the bacterium pathogenicity. Therefore, in this work we used a bioinformatical approach to evaluate the function of ROD21-encoded genes and delve into the characterization of SEN1990, a gene encoding a putative DNA-binding protein. We characterized the predicted structure of SEN1990, finding that this protein contains a three-stranded winged helix-turn-helix (wHTH) DNA-binding domain. Additionally, we identified homologs of SEN1990 among other members of the EARL EGIs. Furthermore, we deleted SEN1990 in Salmonella ser. Enteritidis, finding no differences in the replication/maintenance of the excised ROD21, disconfirming the previous Refseq annotation of the protein. High-throughput RNA-sequencing was carried out to evaluate the effect of the SEN1990 absence on the bacterium global transcription. We found a downregulated expression of oafB, an SPI-17-encoded acetyltransferase involved in O-antigen modification, which was restored when the deletion of SEN1990 was complemented. Our findings suggests that SEN1990 encodes a wHTH domain-containing transcriptional activator that modulates the transcription of oafB from the SPI-17, suggesting a crosstalk between these pathogenicity islands and a possible new role of ROD21 in the pathogenesis of Salmonella ser. Enteritidis.
Project description:White leghorn layers were infected with Salmonella Enteritidis. The cecum were collected at 7 days post infection for total RNA isolation. The significantly expressed microRNAs between infected and non-infected chickens were identified through Solexa sequencing technology.
Project description:We report our results of RNA-seq analysis on Salmonella Enteritidis biofilms and planktonic cells of the wild type and its cpxR mutant
Project description:Salmonella is a major foodborne pathogen that causes approximately 1.35 million infections annually in the US and remains a leading cause of poultry-associated foodborne illness. To improve chickens' resistance to this pathogen, it is important to understand the mucosal immune mechanisms that govern intestinal defense. Intraepithelial lymphocytes (IELs) positioned between intestinal epithelial cells provide frontline immune surveillance against enteric pathogens. However, a comprehensive characterization of IEL subtype responses to Salmonella infection remains incomplete. Therefore, we conducted this study to examine IEL subtypes and their mechanisms in response to a Salmonella enterica serovar Enteritidis (S. Enteritidis) challenge using a combination of spectral flow cytometry and single-cell RNA sequencing (scRNA-seq). Fifty specific-pathogen-free (SPF) day-old chicks were reared to 21 days of age and then assigned to S. Enteritidis-challenged (SE; 1.62 × 10⁸ CFU/bird, oral gavage) or control (CN; PBS) groups (n = 25/group). On day 2 post infection (2 dpi) and 6 dpi, eight birds per group were euthanized by CO2 asphyxiation to collect liver and ceca for bacteriology and ileum for IEL acquisition. Body weights were recorded at 0, 2, and 6 dpi. Bacteriological findings confirmed the challenge: the SE group harbored S. Enteritidis at both time points, while body weight gain was only lower at 2 dpi in the SE group, indicating a transient dip in performance due to Salmonella infection. Flow cytometry results showed that Salmonella challenge increased the proportion of TCRγδ+CD8αβ+ cytotoxic IELs at 2 dpi, as well as the overall IEL proportion at 2 and 6 dpi. Notably, scRNA-seq identified clusters of progenitor T cells and innate-like cytotoxic T cells that significantly expanded in SE-challenged birds at 2 dpi, indicating rapid mobilization of an innate-like cytotoxic response. Integration of flow cytometry and scRNA-seq data provided evidence that cytotoxic T cells expressing CD8αβ acquire innate-like transcriptional signatures within the intestinal epithelial compartment, suggesting functional reprogramming that enables rapid antigen responses. Trajectory analysis identified a robust differentiation pathway from progenitor T cells through activated CD8⁺ T cells to innate-like CTL as the terminal fate, with quiescent stem-like resident memory T cells serving as an upstream reservoir. These findings reveal a previously uncharacterized innate-like cytotoxic IEL response as a critical early defense mechanism against Salmonella in poultry and identify self-renewing stem-like Trm cells as a reservoir for rapid IEL effector differentiation.