Project description:This study compares the global transcriptomes of highly pathogenic bovine-adapted S. enterica serovar Dublin and the less pathogenic bovine-adapted serovar Cerro during interactions with bovine epithelial cells, to identify genes that impact serovar-related outcomes of S. enterica infections in dairy animals
Project description:Single-molecule read technologies allow for detection of epigenomic base modifications during routine sequencing by analysis of kinetic data during the reaction, including the duration between base incorporations at the elongation site (the "inter-pulse duration.") Methylome data associated with a closed de novo bacterial genome of Salmonella enterica subsp. enterica serovar Javiana str. CFSAN001992 was produced and submitted to the Gene Expression Omnibus.
Project description:The 47-kbp plasmid pGFT1 from Salmonella enterica subsp. enterica serovar Dublin mediated tetracycline resistance via a tet(A) gene located on an integrated copy of a Tn1721-analogous transposon. The integration site of the transposon was located within the reading frame of a fip gene. Plasmid pGFT1 was shown to be conjugative and to be able to replicate and express tetracycline resistance in Escherichia coli.
Project description:Single-molecule read technologies allow for detection of epigenomic base modifications during routine sequencing by analysis of kinetic data during the reaction, including the duration between base incorporations at the elongation site (the "inter-pulse duration.") Methylome data associated with a closed de novo bacterial genome of Salmonella enterica subsp. enterica serovar Javiana str. CFSAN001992 was produced and submitted to the Gene Expression Omnibus. Single-sample sequencing and base modification detection of cultured isolate of a foodborne pathogen.
Project description:The Salmonella enterica serovar Typhimurium (ST) mutant lacking the msbB gene (ΔmsbB) has been widely studied as a candidate for attenuated bacterial vectors in therapeutic applications. Deletion of msbB results in LPS with under-acylated lipid A, which lowers endotoxicity while maintaining structural integrity. This attenuation has traditionally been attributed to reduced TLR4 activation due to weaker interaction between the modified lipid A and TLR4. In our study, we confirmed that ΔmsbB ST was less lethal than wild-type (WT) ST in a mouse sepsis model. However, this difference persisted even in TLR4- and caspase-11-deficient mice, suggesting that LPS signaling is not the primary determinant of virulence. In vitro, bone marrow–derived macrophages (BMDMs) from TLR4- or caspase-11-deficient mice showed only modest reductions in ST-induced cell death and cytokine production. Importantly, ΔmsbB ST behaved similarly to WT ST in these assays, further indicating that LPS-mediated signaling is not central to the observed attenuation. Additionally, the mutant exhibited increased outer membrane permeability, likely contributing to its heightened antibiotic sensitivity—and reduced motility due to lower flagellin protein levels.
Project description:Salmonella enterica Serovar Typhimurium (S. Typhimurium) causes enterocolitis in humans and calves characterized by diarrhea and polymorphonuclear cell (PMN) influx to the intestinal mucosa. The Salmonella Type III Secretion System encoded at Pathogenicity Island I (SPI-1) translocates the Salmonella effector proteins SipA, SopA, SopB, SopD, and SopE2 into the host epithelial cell cytoplasm. These five effector proteins act in concert to induce fluid secretion and transcription of C-X-C chemokines, which serve to recruit PMNs to the intestine. While the individual molecular interactions of these Salmonella proteins with cultured host cells have been extensively characterized, their combined role in the generation of fluid secretion and inflammation is less well understood. A bovine ligated ileal loop model was used in conjunction with a custom bovine microarray to determine intestinal response to acute S. Typhimurium infection in the calf. Gene expression responses to both wild type S. Typhimurium a delta sipA, sopABDE2 mutant were measured at seven times during the initial 12 hours of infection. Microarray analysis confirmed increased expression of genes encoding proteins previously associated with immune response to Salmonella spp. infection. Gene expression changes were mapped to molecular interaction pathways and changes in expression of mechanistic genes, which are defined as perturbed genes identified by Bayesian genetic network modeling, were strongly involved in the mechanisms of the host immune response. In addition to correctly identifying known effects of wild type S. Typhimurium on host (bovine) gene expression, Bayesian genetic network modeling identified novel effects of S. Typhimurium on several molecular interaction pathways. Novel effects impacted gene regulation in the following pathways: adipocytokine signaling, insulin signaling, complement and coagulation cascades, axon guidance, gap junction, neuroactive ligand-receptor interaction, long-term depression, long-term potentiation, melanogenesis, and natural killer cell mediated cytotoxicity. Known effects were observed in the following pathways: regulation of actin cytoskeleton, apoptosis, cytokine-cytokine receptor interaction, cell adhesion molecules (CAMs), MAPK signaling, calcium signaling, Jak-STAT signaling, leukocyte transendothelial migration, adherens junction, tight junction, and ECM-receptor interactions, phosphatidylinositol signaling system, and antigen processing and presentation. Quantitative real-time PCR was used to verify the expression of some of these mechanistic genes.