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Salmonella porins

Kathrin S Fröhlich, Katharina Haneke, Kai Papenfort, Jörg Vogel
Model enteric bacteria such as Escherichia coli and Salmonella enterica express hundreds of small non-coding RNAs (sRNAs), targets for most of which are yet unknown. Some sRNAs are remarkably well conserved, indicating that they serve cellular functions that go beyond the necessities of a single species. One of these 'core sRNAs' of largely unknown function is the abundant ∼100-nucleotide SdsR sRNA which is transcribed by the general stress σ-factor, σ(S) and accumulates in stationary phase. In Salmonella, SdsR was known to inhibit the synthesis of the species-specific porin, OmpD...
July 12, 2016: Nucleic Acids Research
Juan Manuel Carreño, Christian Perez-Shibayama, Cristina Gil-Cruz, Andrea Printz, Rodolfo Pastelin, Armando Isibasi, Dominic Chariatte, Yutaka Tanoue, Constantino Lopez-Macias, Bruno Gander, Burkhard Ludewig
Salmonella (S.) enterica infections are an important global health problem with more than 20 million individuals suffering from enteric fever annually and more than 200,000 lethal cases per year. Although enteric fever can be treated appropriately with antibiotics, an increasing number of antibiotic resistant Salmonella strains is detected. While two vaccines against typhoid fever are currently on the market, their availability in subtropical endemic areas is limited because these products need to be kept in uninterrupted cold chains...
July 29, 2016: Vaccine
Natalia Cernicchiaro, Samuel E Ives, Thomas S Edrington, Tiruvoor G Nagaraja, David G Renter
The efficacy of a Salmonella vaccine for reducing fecal shedding of Salmonella during the finishing period and lymph node (LN) carriage at harvest was investigated in commercial feedlot cattle. The study was designed as a pen-level randomized complete block with two treatment groups, a Salmonella Newport siderophore receptor and porin proteins-based vaccine (VAC) and a nonvaccinated control (CON). Cattle were randomly allocated into 24 pens within 12 blocks based on the time of allocation. Twenty to 25 fecal pats were collected from each of the study pen floors once a month from June to August 2013...
September 2016: Foodborne Pathogens and Disease
Howard T H Saw, Mark A Webber, Shazad Mushtaq, Neil Woodford, Laura J V Piddock
OBJECTIVES: The objective of this study was to study the contribution of the multidrug resistance AcrAB-TolC efflux system to carbapenem resistance in carbapenemase-producing Enterobacteriaceae and the impact of the efflux inhibitor PABN on this resistance. METHODS: Klebsiella pneumoniae, Escherichia coli, Salmonella enterica serovar Typhimurium and their corresponding AcrAB-TolC mutants, each carrying carbapenemase-carrying plasmids (pKpQIL-UK with blaKPC and pNDM-HK with blaNDM), were tested for their susceptibility to six β-lactam antibiotics according to the BSAC agar dilution method...
June 2016: Journal of Antimicrobial Chemotherapy
Jitendra Kumar, Vijay K Sharma, Dheeraj K Singh, Ashish Mishra, Surendra K Gond, Satish K Verma, Anuj Kumar, Ravindra Nath Kharwar
The endophytic Streptomyces coelicolor strain AZRA 37 was isolated from the surface sterilized root of Azadirachta indica A. Juss., commonly known as neem plant in India. Since only a few reports are available regarding epigenetic modulations of microbial entities, S. coelicolor was treated with different concentrations of 5-azacytidine for this purpose and evaluated for its antibacterial potential against five human pathogenic bacteria (Aeromonas hydrophila IMS/GN11, Enterococcus faecalis IMS/GN7, Salmonella typhi MTCC 3216, Shigella flexneri ATCC 12022 and Staphylococcus aureus ATCC 25923)...
2016: PloS One
Thatyane M Nobre, Michael W Martynowycz, Konstantin Andreev, Ivan Kuzmenko, Hiroshi Nikaido, David Gidalevitz
Small hydrophilic antibiotics traverse the outer membrane of Gram-negative bacteria through porin channels. Large lipophilic agents traverse the outer membrane through its bilayer, containing a majority of lipopolysaccharides in its outer leaflet. Genes controlled by the two-component regulatory system PhoPQ modify lipopolysaccharides. We isolate lipopolysaccharides from isogenic mutants of Salmonella sp., one lacking the modification, the other fully modified. These lipopolysaccharides were reconstituted as monolayers at the air-water interface, and their properties, as well as their interaction with a large lipophilic drug, novobiocin, was studied...
December 15, 2015: Biophysical Journal
Brigitta Kurenbach, Delphine Marjoshi, Carlos F Amábile-Cuevas, Gayle C Ferguson, William Godsoe, Paddy Gibson, Jack A Heinemann
UNLABELLED: Biocides, such as herbicides, are routinely tested for toxicity but not for sublethal effects on microbes. Many biocides are known to induce an adaptive multiple-antibiotic resistance phenotype. This can be due to either an increase in the expression of efflux pumps, a reduced synthesis of outer membrane porins, or both. Exposures of Escherichia coli and Salmonella enterica serovar Typhimurium to commercial formulations of three herbicides-dicamba (Kamba), 2,4-dichlorophenoxyacetic acid (2,4-D), and glyphosate (Roundup)-were found to induce a changed response to antibiotics...
2015: MBio
Yi-Lin Tsai, Min-Cheng Wang, Po-Ren Hsueh, Ming-Che Liu, Rouh-Mei Hu, Yue-Jin Wu, Shwu-Jen Liaw
Proteus mirabilis isolates commonly have decreased susceptibility to imipenem. Previously, we found P. mirabilis hfq mutant was more resistant to imipenem and an outer membrane protein (OMP) could be involved. Therefore, we investigated the role of this OMP in carbapenem susceptibility. By SDS-PAGE we found this OMP (named ImpR) was increased in hfq mutant and LC-MS/MS revealed it to be the homologue of Salmonella YbfM, which is a porin for chitobiose and subject to MicM (a small RNA) regulation. We demonstrated that ImpR overexpression resulted in increased carbapenem MICs in the laboratory strain and clinical isolates...
2015: PloS One
Daniel Aguayo, Nicolás Pacheco, Eduardo H Morales, Bernardo Collao, Roberto Luraschi, Carolina Cabezas, Paulina Calderón, Fernando González-Nilo, Fernando Gil, Iván L Calderón, Claudia P Saavedra
OmpD is the major Salmonella enterica serovar Typhimurium (S. Typhimurium) porin and mediates hydrogen peroxide (H2O2) influx. The results described herein extend this finding to hypochlorous acid (HOCl), another reactive oxygen species that is also part of the oxidative burst generated by the phagosome. S. Typhimurium cells lacking OmpD show decreased HOCl influx, and OmpD-reconstituted proteoliposomes show an increase in the uptake of the toxic compound. To understand this physiologically relevant process, we investigated the role of key OmpD residues in H2O2 and NaOCl transport...
February 15, 2015: Archives of Biochemistry and Biophysics
Antonio Galiana, Laura Sánchez-Guillén, Juan Carlos Rodríguez, Rosa Cremades, Migue Santibañez, Rafaela Ferrari, Montserrat Ruiz-García, Pilar López, Gloria Royo
Introduction. The marA, soxS, ramA, acrB and ompF genes have been studied in order to characterize mechanisms of AcrAB-TolC active efflux pumps and membrane permeability alterations that reduce fluoroquinolones susceptibility in Salmonella spp. Methods. Mutations in marA, soxS, ramA, acrB and ompF genes were detected, as well as their expression levels in presence and absence of ciprofloxacin, calculating the level of change between them by qPCR. Data were analysed by using SPSS 19.0. Results. No mutations in these genes were found, but both AcrAB-TolC regulatory genes and structural acrB gene expression were affected by ciprofloxacin in both mutant strains and wild type bacterial strains (WT)...
December 2014: Revista Española de Quimioterapia: Publicación Oficial de la Sociedad Española de Quimioterapia
Saeeda Bobat, Matthew Darby, Dunja Mrdjen, Charlotte Cook, Erin Logan, Jennifer Auret, Elizabeth Jones, Corinna Schnoeller, Adriana Flores-Langarica, Ewan A Ross, Alykhan Vira, Constantino López-Macías, Ian R Henderson, James Alexander, Frank Brombacher, William G Horsnell, Adam F Cunningham
BACKGROUND: The impact of exposure to multiple pathogens concurrently or consecutively on immune function is unclear. Here, immune responses induced by combinations of the bacterium Salmonella Typhimurium (STm) and the helminth Nippostrongylus brasiliensis (Nb), which causes a murine hookworm infection and an experimental porin protein vaccine against STm, were examined. METHODOLOGY/PRINCIPAL FINDINGS: Mice infected with both STm and Nb induced similar numbers of Th1 and Th2 lymphocytes compared with singly infected mice, as determined by flow cytometry, although lower levels of secreted Th2, but not Th1 cytokines were detected by ELISA after re-stimulation of splenocytes...
December 2014: PLoS Neglected Tropical Diseases
Adam F Cunningham, Adriana Flores-Langarica, Saeeda Bobat, Carmen C Dominguez Medina, Charlotte N L Cook, Ewan A Ross, Constantino Lopez-Macias, Ian R Henderson
There are multiple, distinct B-cell populations in human beings and other animals such as mice. In the latter species, there is a well-characterized subset of B-cells known as B1 cells, which are enriched in peripheral sites such as the peritoneal cavity but are rare in the blood. B1 cells can be further subdivided into B1a and B1b subsets. There may be additional B1 subsets, though it is unclear if these are distinct populations or stages in the developmental process to become mature B1a and B1b cells. A limitation in understanding B1 subsets is the relative paucity of specific surface markers...
2014: Frontiers in Immunology
Francisco Ipinza, Bernardo Collao, Debbie Monsalva, Victor H Bustamante, Roberto Luraschi, Melissa Alegría-Arcos, Daniel E Almonacid, Daniel Aguayo, Iván L Calderón, Fernando Gil, Carlos A Santiviago, Eduardo H Morales, Edmundo Calva, Claudia P Saavedra
Salmonella Typhimurium is the etiological agent of gastroenteritis in humans and enteric fever in mice. Inside these hosts, Salmonella must overcome hostile conditions to develop a successful infection, a process in which the levels of porins may be critical. Herein, the role of the Salmonella Typhimurium porin OmpD in the infection process was assessed for adherence, invasion and proliferation in RAW264.7 mouse macrophages and in BALB/c mice. In cultured macrophages, a ΔompD strain exhibited increased invasion and proliferation phenotypes as compared to its parental strain...
2014: PloS One
Christian Perez-Shibayama, Cristina Gil-Cruz, Rodolfo Pastelin-Palacios, Luisa Cervantes-Barragan, Emiliano Hisaki, Qian Chai, Lucas Onder, Elke Scandella, Tommy Regen, Ari Waisman, Armando Isibasi, Constantino Lopez-Macias, Burkhard Ludewig
Abs play a significant role in protection against the intracellular bacterium Salmonella Typhi. In this article, we investigated how long-term protective IgM responses can be elicited by a S. Typhi outer-membrane protein C- and F-based subunit vaccine (porins). We found that repeated Ag exposure promoted a CD4(+) T cell-dependent germinal center reaction that generated mutated IgM-producing B cells and was accompanied by a strong expansion of IFN-γ-secreting T follicular helper cells. Genetic ablation of individual cytokine receptors revealed that both IFN-γ and IL-17 are required for optimal germinal center reactions and production of porin-specific memory IgM(+) B cells...
June 1, 2014: Journal of Immunology: Official Journal of the American Association of Immunologists
J M Villarreal, N Becerra-Lobato, J E Rebollar-Flores, L Medina-Aparicio, E Carbajal-Gómez, M L Zavala-García, A Vázquez, R M Gutiérrez-Ríos, L Olvera, S Encarnación, A G Martínez-Batallar, E Calva, I Hernández-Lucas
A characterization of the LtrR regulator, an S. Typhi protein belonging to the LysR family is presented. Proteomics, outer membrane protein profiles and transcriptional analyses demonstrated that LtrR is required for the synthesis of OmpR, OmpC and OmpF. DNA-protein interaction analysis showed that LtrR binds to the regulatory region of ompR and then OmpR interacts with the ompC and ompF promoters inducing porin synthesis. LtrR-dependent and independent ompR promoters were identified, and both promoters are involved in the synthesis of OmpR for OmpC and OmpF production...
June 2014: Molecular Microbiology
Mario Alberto Flores-Valdez, Marcos Fernández-Mora, Miguel Ángel Ares, Jorge A Girón, Edmundo Calva, Miguel Ángel De la Cruz
The Salmonella enterica ompS1 gene encodes a quiescent porin that belongs to the OmpC/OmpF family. In the present work we analysed the regulatory effects of OmpR phosphorylation on ompS1 expression. We found that in vivo, OmpR in its phosphorylated form (OmpR-P) was important in the regulation of the two ompS1 promoters: OmpR-P activated the P1 promoter and repressed the P2 promoter in an EnvZ-dependent manner; expression occurs from the P2 promoter in an ompR mutant. In vitro, OmpR-P had a higher DNA-binding-affinity to the ompS1 promoter region than OmpR and OmpRD55A, showing an affinity even higher than that of equivalent DNA regions in the 5'-upstream regulatory sequence of the major porin-encoding genes ompC and ompF...
April 2014: Microbiology
María Antonia Sánchez-Romero, Josep Casadesús
Antibiotic-resistant isolates of Salmonella enterica were selected on plates containing lethal concentrations of rifampicin, kanamycin, and nalidixic acid. The stability of the resistance phenotype was scored after nonselective growth. Rifampicin-resistant (Rif(r)) isolates were stable, suggesting that they had arisen by mutation. Mutations in the rpoB gene were detected indeed in Rif(r) mutants. In contrast, a fraction of kanamycin-resistant (Km(r)) and nalidixic acid-resistant (Nal(r)) isolates showed reduced resistance after nonselective growth, suggesting that mechanisms other than mutation had contributed to bacterial survival upon lethal selection...
January 7, 2014: Proceedings of the National Academy of Sciences of the United States of America
Ge Zhang, Timothy C Meredith, Daniel Kahne
Lipopolysaccharide is a highly acylated saccharolipid located on the outer leaflet of the outer membrane of Gram-negative bacteria. Lipopolysaccharide is critical to maintaining the barrier function preventing the passive diffusion of hydrophobic solutes such as antibiotics and detergents into the cell. Lipopolysaccharide has been considered an essential component for outer membrane biogenesis and cell viability based on pioneering studies in the model Gram-negative organisms Escherichia coli and Salmonella...
December 2013: Current Opinion in Microbiology
Denis Leclerc, Marie Rivest, Cindy Babin, Constantino López-Macias, Pierre Savard
BACKGROUND: The USA 2004 influenza virus outbreak H3N8 in dogs heralded the emergence of a new disease in this species. A new inactivated H3N8 vaccine was developed to control the spread of the disease but, as in humans and swine, it is anticipated that the virus will mutate shift and drift in the dog population. Therefore, there is a need for a vaccine that can trigger a broad protection to prevent the spread of the virus and the emergence of new strains. METHODOLOGY AND PRINCIPAL FINDINGS: The universal M2e peptide is identical in almost all the H3N8 influenza strains sequenced to date and known to infect dogs...
2013: PloS One
Sara Sandrini, Rikesh Masania, Fatima Zia, Richard Haigh, Primrose Freestone
Acquisition of iron from key innate immune defence proteins such as transferrin (Tf) and lactoferrin is an important mechanism by which pathogenic bacteria obtain essential iron for growth within their host. Bacterial species that do not produce siderophores often use specific Tf-binding proteins, the best characterized being the Neisseriaceae-type Tf-binding proteins TbpA and TbpB. Previous work from our laboratory has shown that siderophore-producing enteric species such as Escherichia coli also readily bind Tf, although no genomic evidence exists for Tbp-like Tf-binding proteins...
December 2013: Microbiology
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