Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
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| role of fimw, fimy, and fimz in regulating the expression of type i fimbriae in salmonella enterica serovar typhimurium. | type i fimbriae in salmonella enterica serovar typhimurium are surface appendages that facilitate binding to eukaryotic cells. expression of the fim gene cluster is known to be regulated by three proteins--fimw, fimy, and fimz--and a trna encoded by fimu. in this work, we investigated how these proteins and trna coordinately regulate fim gene expression. our results indicate that fimy and fimz independently activate the p(fima) promoter which controls the expression of the fim structural genes. ... | 2009 | 19218381 |
| subspecies iiia and iiib salmonellae are defective for colonization of murine models of salmonellosis compared to salmonella enterica subsp. i serovar typhimurium. | non-subspecies i salmonellae are commensals of cold-blooded vertebrates and cause sporadic disease in mammals. the reasons why non-subspecies i salmonellae do not circulate in populations of warm-blooded vertebrates, but instead only cause occasional disease in this niche, are unknown. we examined the ability of salmonella enterica subsp. iiia (subsp. arizonae) and subsp. iiib (subsp. diarizonae) isolates to grow competitively with subspecies i (serovar typhimurium) atcc 14028 in vitro, to colon ... | 2009 | 19218378 |
| [evolutionary engineering in salmonella: emergence of hybrid virulence-resistance plasmids in non-typhoid serotypes]. | an example of evolutive engineering in bacterial pathogens is the emergence of hybrid virulence-resistance (vr) plasmids in salmonella enterica, resulting from an association between antimicrobial resistance determinants and specific virulence plasmids of the s. typhimurium and s. choleraesuis serotypes. vr plasmids all possess the spv (salmonella plasmid virulence) operon, which is involved in systemic infection; however, they differ in the presence of other virulence determinants and in the re ... | 2009 | 19218002 |
| a comparison of two pcr-based typing methods with pulsed-field gel electrophoresis in salmonella enterica serovar enteritidis. | two novel molecular typing methods, multiple-locus variable-number tandem repeats (vntr) analysis (mlva) and multiple amplification of phage loci typing (maplt), were compared with pulsed-field gel electrophoresis (pfge) for the discrimination of 128 salmonella enterica serovar enteritidis (s. enteritidis) isolates. selected epidemiologically unrelated isolates represented a cross-section of phage types routinely isolated in australia and included 28 isolates that could not be assigned a phage t ... | 2009 | 19217348 |
| construction of highly attenuated salmonella enterica serovar typhimurium live vectors for delivering heterologous antigens by chromosomal integration. | attenuated live salmonella enterica serovar typhimurium is a versatile organism for the generation of live recombinant vaccines for mucosal immunization and various approaches were devised for the stable and efficient expressions of heterologous antigens by attenuated s. enterica strains. phage lamda red recombinase has recently been devised for gene replacements in s. enterica after introduction of pcr products as a one-step deletion approach and flp-mediated recombination allows the subsequent ... | 2008 | 19216101 |
| intestinal mmc-related electric fields and pancreatic juice control the adhesion of gram-positive and gram-negative bacteria to the gut epithelium--in vitro study. | the adhesion of six different lactobacillus and lactococcus and three pathogenic escherichia and salmonella strains was studied using caco-2 cell line. in this in vitro model system the influence of weak electric field (ef) on bacterial adhesion was tested. the ef source was the in vitro reconstruction of spiking potentials recorded in the duodenum of a healthy calf during one myoelectrical migration complex (mmc) cycle. the ability to adhere to caco-2 cells of bacteria belonging to two groups, ... | 2008 | 19212012 |
| effect of a direct-fed microbial (primalac) on structure and ultrastructure of small intestine in turkey poults. | the effects of dietary supplementation of the direct-fed microbial (dfm) primalac in mash or crumbled feed on histological and ultrastructural changes of intestinal mucosa was determined in 2 populations of poults; 1 with and 1 without a salmonella spp. challenge. three hundred thirty-six 1-d-old female large white turkey poults were randomly distributed into 8 treatment groups with 6 replicates of 7 poults in each pen. the poults were placed on 1 of 4 dietary treatments in a 2 x 2 x 2 factorial ... | 2009 | 19211517 |
| re-emerging chloramphenicol sensitivity and emerging low level ciprofloxacin resistance among salmonella enterica serotype typhi isolates in north india. | ciprofloxacin has become the antibiotic of choice for the treatment of typhoid fever with the emergence and worldwide spread of salmonella enterica typhi strains resistant to chloramphenicol. however, the rampant use of ciprofloxacin gradually led to an increase in its minimum inhibitory concentration against s. enterica typhi. this threatened its therapeutic efficacy and resulted in the re-emergence of chloramphenicol-sensitive s. enterica typhi strains. | 2009 | 19211419 |
| antimicrobial properties of the equine alpha-defensin defa1 against bacterial horse pathogens. | defensins are small effector molecules of the innate immune system, synthesised by various organisms including plants and animals. the peptides act as endogenous antibiotics with an antimicrobial activity against a broad spectrum of microbes including bacteria, fungi and viruses. alpha-defensins are a subgroup of the defensin family, their synthesis is limited to some tissues and furthermore to some mammalian species including the horse. equine defa1 is an enteric alpha-defensin exclusively prod ... | 2009 | 19211153 |
| sequence analysis of escherichia coli o157:h7 bacteriophage phiv10 and identification of a phage-encoded immunity protein that modifies the o157 antigen. | bacteriophage phiv10 is a temperate phage, which specifically infects escherichia coli o157:h7. the nucleotide sequence of the phiv10 genome is 39 104 bp long and contains 55 predicted genes. phiv10 is closely related to two previously sequenced phages, the salmonella enterica serovar anatum (group e1) phage epsilon15 and a prophage from e. coli apec o1. the attachment site of phiv10, like those of its two closest relatives, overlaps the 3' end of guaa in the host chromosome. phiv10 encodes an o ... | 2009 | 19210675 |
| hydrophobic peptides: novel regulators within bacterial membrane. | identification of short coding sequences is challenging, both experimentally and in silico, and functional natural peptides (< 50 amino acids) have to a large extent been overlooked in gram-negative bacteria. recent results have converged to highlight the role of hydrophobic peptides that form a novel class of active molecules in escherichia coli and salmonella enterica serovar typhimurium. these peptides can play a regulatory role by interacting with protein partners at the inner membrane and b ... | 2009 | 19210615 |
| pathogen trafficking pathways and host phosphoinositide metabolism. | phosphoinositide (pi) glycerolipids are key regulators of eukaryotic signal transduction, cytoskeleton architecture and membrane dynamics. the host cell pi metabolism is targeted by intracellular bacterial pathogens, which evolved intricate strategies to modulate uptake processes and vesicle trafficking pathways. upon entering eukaryotic host cells, pathogenic bacteria replicate in distinct vacuoles or in the host cytoplasm. vacuolar pathogens manipulate pi levels to mimic or modify membranes of ... | 2009 | 19208094 |
| a method for investigating protein-protein interactions related to salmonella typhimurium pathogenesis. | we successfully modified an existing method to investigate protein-protein interactions in the pathogenic bacterium salmonella enterica serovar typhimurium (salmonella typhimurium). this method includes (i) addition of a histidine-biotin-histidine tag to the bait proteins via recombinant dna techniques, (ii) in vivo cross-linking with formaldehyde, (iii) tandem affinity purification of bait proteins under fully denaturing conditions, and (iv) identification of the proteins cross-linked to the ba ... | 2009 | 19206470 |
| control of foodborne pathogens and soft-rot bacteria on bell pepper by three strains of bacterial antagonists. | forty-two representative strains of native bacteria associated with fresh peeled baby carrots were isolated and characterized. two of these strains, identified as pseudomonas fluorescens ag3a (pf ag3a) and bacillus yd1, were evaluated in conjunction with another known antagonist, p. fluorescens 2-79 (pf 2-79), for their potential as biocontrol agents of human pathogens (listeria monocytogenes, yersinia enterocolitica, salmonella enterica, and escherichia coli o157:h7) and soft-rot bacteria (erwi ... | 2009 | 19205468 |
| dna recognition by the salmonella enterica serovar typhimurium transcription factor slya. | the salmonella regulatory protein slya is implicated in virulence, survival in macrophages and resistance to oxidative stress and anti-microbial peptides. slya is a member of the marr family of winged-helix transcription factors. systematic mutational analysis of the slya operator sequence and of the predicted dna-binding region of slya shows that no single base pair in the palindromic slya operator sequence is essential for dna binding, and identifies amino acid residues required to allow slya ... | 2008 | 19204896 |
| paracoccidioides brasiliensis vaccine formulations based on the gp43-derived p10 sequence and the salmonella enterica flic flagellin. | paracoccidioidomycosis (pcm) is a systemic granulomatous disease caused by the dimorphic fungus paracoccidioides brasiliensis. anti-pcm vaccine formulations based on the secreted fungal cell wall protein (gp43) or the derived p10 sequence containing a cd4(+) t-cell-specific epitope have shown promising results. in the present study, we evaluated new anti-pcm vaccine formulations based on the intranasal administration of p. brasiliensis gp43 or the p10 peptide in combination with the salmonella e ... | 2009 | 19204092 |
| salmonella administration induces a reduction of wheel-running activity via a tlr5-, but not a tlr4, dependent pathway in mice. | in general, systemic bacterial infections induce sickness behavior. in mice, lipopolysaccharide (lps), a component of gram-negative bacteria, strongly reduces physical activity via toll-like receptor (tlr) 4. however, gram-negative bacteria, such as salmonella, also express flagella containing flagellin (fg) which binds to tlr5 and induces pro-inflammatory cytokine production. it is unclear whether fg induces sickness behavior. to determine whether salmonella administration regulates the reducti ... | 2008 | 19203083 |
| effects of mesalamine (5-aminosalicylic acid) on bacterial gene expression. | 5-aminosalicylic acid (5-asa) is a well-established treatment for inflammatory bowel disease (ibd) and may reduce the risk of colon cancer in patients with chronic colitis, but the mechanisms underlying these effects have not been fully elucidated. although 5-asa delivery is targeted to the distal gut, little is known about its effects on the luminal bacteria that reside there. intestinal bacteria are believed play a role in causing or perpetuating ibd, and bioremediation has been studied as a t ... | 2009 | 19202572 |
| a novel phop-regulated locus encoding the cytolysin clya and the secreted invasin taia of salmonella enterica serovar typhi is involved in virulence. | salmonella enterica serovar typhi causes a human-restricted systemic infection called typhoid fever. we have identified a typhi genomic region encoding two orfs, sty1498 and sty1499, that are expressed during infection of human macrophages and organized in an operon. sty1498 corresponds to clya, which encodes a pore-forming cytolysin, and sty1499 encodes a 27 kda protein, without any attributed function, which we have named taia (typhi-associated invasin a). in order to evaluate the roles of the ... | 2009 | 19202096 |
| surface display of the receptor-binding domain of the f17a-g fimbrial adhesin through the autotransporter aida-i leads to permeability of bacterial cells. | surface exposure of antigens on bacterial cells can be critical for eliciting an effective antibody response. therefore, we investigated the cellular localization of the fimbrial f17a-g receptor-binding domain, fused to the translocator domain of the aida-i autotransporter. synthesis of the fusion protein, under the control of the l-arabinose-inducible pbad promoter, was shown to permeabilize escherichia coli k-12 and salmonella enterica serovar typhimurium cells. the presence of permeable cells ... | 2009 | 19202095 |
| gfp plasmid-induced defects in salmonella invasion depend on plasmid architecture, not protein expression. | we have investigated the impact of plasmids and gfp expression on invasion of cultured epithelial cells by salmonella enterica typhimurium strain sl1344. the invasiveness of sl1344 carrying plasmids derived from pbr322, encoding promoterless gfp or constitutively expressed rpsm-gfp, was compared under optimal growth conditions with that of sl1344(pbr322), unmodified sl1344 and a strain with chromosome-integrated rpsm-gfp. the strain carrying pbr322 exhibited normal invasion, but the presence of ... | 2009 | 19202094 |
| prevalence and characterization of salmonellae in commercial ground beef in the united states. | commercially produced ground beef samples (n = 4,136) were collected from seven regions of the united states over a 24-month period (july 2005 to june 2007) and analyzed for the presence of salmonella enterica by using methods that concurrently provided total prevalence and enumerable levels. the overall prevalence of salmonella strains was 4.2%. enumeration showed that 94.2% were present at levels below 2 cfu/g. regional monthly prevalences of salmonella strains varied from 1.8% to 6.5% but wer ... | 2009 | 19201965 |
| innate immunity mediated by myd88 signal is not essential for induction of lipopolysaccharide-specific b cell responses but is indispensable for protection against salmonella enterica serovar typhimurium infection. | salmonella organisms are gram negative and facultative anaerobic bacteria that cause typhoid fever in humans. in this study, we evaluated lps-specific adaptive immunity in innate immune-deficient mice after oral administration of attenuated salmonella enterica serovar typhimurium (s. typhimurium) strains. of interest, identical levels of lps-specific igg and iga abs were elicited in the systemic (i.e., serum and spleen) and mucosal (i.e., fecal extract and small intestine) compartments of wild-t ... | 2009 | 19201885 |
| a conserved alpha-helix essential for a type vi secretion-like system of francisella tularensis. | francisella tularensis harbors genes with similarity to genes encoding components of a type vi secretion system (t6ss) recently identified in several gram-negative bacteria. these genes include igla and iglb encoding igla and iglb, homologues of which are conserved in most t6sss. we used a yeast two-hybrid system to study the interaction of the igl proteins of f. tularensis lvs. we identified a region of igla, encompassing residues 33 to 132, necessary for efficient binding to iglb, as well as f ... | 2009 | 19201795 |
| distribution of mutation frequencies among salmonella enterica isolates from animal and human sources and genetic characterization of a salmonella heidelberg hypermutator. | hypermutation is an important mechanism used by different salmonella enterica subspecies enterica to regulate genetic stability in adaptation to changing environments, including antimicrobial treatments and industrial processes. strong hypermutator strains generally contain a mutation in genes of the methyl mismatch repair (mmr) system and have mutation frequencies up to 1000-fold higher than wild type strains. the objectives of this study were to determine the distribution of mutation frequenci ... | 2009 | 19201550 |
| expression profile of toll-like receptors within the gastrointestinal tract of 2-day-old salmonella enteriditis-infected broiler chickens. | salmonella enterica serovar enteriditis (se) causes a majority of foodborne illness in the u.s. a more productive avian innate immune response could reduce bacterial colonization and the incidence of infection in humans. however, quantification and comparison of the toll-like receptors (tlr), a component of the innate immune system that recognize bacterial pathogens, and their response to se colonization across the avian gastrointestinal (gi) tract has not been reported. therefore, we assessed t ... | 2009 | 19201111 |
| methods to monitor autophagy of salmonella enterica serovar typhimurium. | autophagy is an important component of the mammalian innate immune system and is able to specifically target intracellular bacterial pathogens. salmonella enterica serovar typhimurium is an intracellular pathogen that causes gastroenteritis in humans. autophagy has been shown to target s. typhimurium during in vitro infection of mammalian cultured cells and protects the cytosol of these cells from bacterial colonization. here we discuss autophagic sequestration of s. typhimurium and how it can b ... | 2009 | 19200891 |
| expression of porcine toll-like receptor 2, 4 and 9 gene transcripts in the presence of lipopolysaccharide and salmonella enterica serovars typhimurium and choleraesuis. | salmonella enterica serovar typhimurium (st) and choleraesuis (sc) are among the most frequently isolated salmonellae serovars causing enteric disease in swine. enteric disease in young pigs is of major concern in modern production systems due to the negative implications on animal health, food safety and economic return. epithelial cells express toll-like receptors (tlr) that recognize conserved microbial structures and act as mediators of innate and adaptive immune responses. however, little i ... | 2009 | 19200608 |
| distribution and genotypic characterization of salmonella serovars isolated from tropical seafood of cochin, india. | to determine the distribution of salmonella serovars in seafood and to examine the intraserovar genetic variations in salmonella enterica subsp. enterica serovar rissen and salmonella weltevreden by polymerase chain reaction (pcr)-ribotyping and enterobacterial repetitive intergenic consensus (eric)-pcr methods. | 2009 | 19200318 |
| molecular characterization of antimicrobial resistance in salmonella isolated from animals in japan. | aims: to investigate the prevalence of integrons and antimicrobial resistance genes in salmonella recovered from animals in japan. methods and results: forty-eight out of ninety-four (51.1%) salmonella isolates showed multidrug resistance phenotypes and harboured at least one antimicrobial resistance gene. twenty-two out of forty-seven (46.8%) salmonella enterica serovar typhimurium that were multidrug-resistant were of definitive phage type dt104. class 1 integrons were identified in 34/94 isol ... | 2009 | 19200308 |
| the structure and biological aspects of peptide antibiotic microcin j25. | microcin j25 (mccj25) is a plasmid-encoded peptide of 21 l-amino acids (g1-g-a-g-h5-v-p-e-y-f10-v-g-i-g-t15-p-i-s-f-y20-g), excreted to the medium by an escherichia coli strain. mccj25 is active on gram-negative bacteria related to the producer strain, including some pathogenic strains. the four-plasmid genes mcjabcd, are involved in mccj25 production: mcja encodes a 58-residue precursor, mcjb and mcjc codify two processing enzymes required for the in vivo synthesis of the mature peptide and mcj ... | 2009 | 19199920 |
| effects of the dicarboxylic acids malate and fumarate on e. coli o157:h7 and salmonella enterica typhimurium populations in pure culture and in mixed ruminal microorganism fermentations. | the dicarboxylic acids malate and fumarate increase ruminal ph, reduce methane production, increase propionate and total volatile fatty acid (vfa) production, and reduce lactic acid accumulation in a manner similar to ionophores. these acids stimulate the ruminal bacterium selenomonas ruminantium to ferment lactate to produce propionate. thus, dicarboxylic acids have been suggested as nonantibiotic modifiers of the ruminal fermentation, but their impact on ruminal microbial ecology remains unkno ... | 2009 | 19194750 |
| rethinking typhoid fever vaccines: implications for travelers and people living in highly endemic areas. | 2009 | 19192128 | |
| recombinant attenuated salmonella harboring 4-1bb ligand gene enhances cellular immunity. | to transfect antigen presenting cells (apcs) with 4-1bb ligand dna by attenuated salmonella enterica serovar typhimurium in vivo, and to observe the effects of ectogenous 4-1bbl on the immune functions of infected rats. | 2009 | 19187795 |
| serovar distribution and antimicrobial susceptibility of swine salmonella isolates from clinically ill pigs in diagnostic submissions from indiana in the united states. | to determine serovar distribution and levels of antimicrobial susceptibility of salmonella isolated from clinically ill pigs in diagnostic submissions. | 2009 | 19187513 |
| synergistic role of curli and cellulose in cell adherence and biofilm formation of attaching and effacing escherichia coli and identification of fis as a negative regulator of curli. | curli are adhesive fimbriae of escherichia coli and salmonella enterica. expression of curli (csga) and cellulose (bcsa) is co-activated by the transcriptional activator csgd. in this study, we investigated the contribution of curli and cellulose to the adhesive properties of enterohaemorragic (ehec) o157:h7 and enteropathogenic e. coli (epec) o127:h6. while single mutations in csga, csgd or bcsa in epec and ehec had no dramatic effect on cell adherence, double csgabcsa mutants were significantl ... | 2009 | 19187284 |
| the cysteine 354 and 277 residues of salmonella enterica serovar typhi envz are determinants of autophosphorylation and ompr phosphorylation. | an initial biochemical characterization of the salmonella enterica serovar typhi (s. typhi) envz sensor protein and several mutant derivatives was performed. autophosphorylation levels were higher for escherichia coli envz, intermediate for s. enterica serovar typhimurium envz and very low for s. typhi envz, in spite of their high amino acid sequence identity. consequently, ompr phosphorylation was related to envz autophosphorylation. among the mutant derivatives, a c354g mutation in s. typhi en ... | 2009 | 19187206 |
| importance of subunit vaccine antigen of major fli c antigenic site of salmonella enteritidis ii: a challenge trial. | salmonella enterica subsp. enterica serovar enteritidis (se) infection in chickens shows a mild pathogenicity except for young ages, compared with other animals, and laying hens sometimes produce se-contaminated eggs leading to public health concerns. to reduce the problem, se bacterin in poultry farms has been applied. we previously demonstrated that a subunit antigen, g.m. part polypeptide in se-fli c (sep 9), could be a candidate subunit antigen of se vaccine which may show less side effects ... | 2009 | 19186198 |
| further studies on vertical transmission and persistence of salmonella enterica serovar enteritidis phage type 4 in chickens. | one-week-old commercial layers were infected orally with 10(8) colony forming units of salmonella enterica serovar enteritidis phage type 4. no mortality was observed. the inoculated organism was isolated in decreasing viable numbers from a number of tissues, particularly the spleen, liver and caeca. organisms present in the spleen were primarily localized within macrophages. no salmonella enteritidis organisms were isolated between 10 and 24 weeks of age, when the experiment was terminated afte ... | 2001 | 19184915 |
| observations on the persistence and vertical transmission of salmonella enterica serovars pullorum and gallinarum in chickens: effect of bacterial and host genetic background. | commercial laying hens inoculated with a strain of salmonella enterica ser. pullorum when they were 4 days old showed no morbidity, but harboured infection until they came into lay, and then produced s. pullorum-contaminated eggs and infected progeny. there was limited evidence of transmission of maternal immunity to the progeny. attempts were made to set up similar infections in hens with salmonella gallinarum, but without success. infection either resulted in clinical disease or elimination of ... | 2001 | 19184904 |
| experimental salmonella enterica serovar pullorum infection in two commercial varieties of laying hens. | an experiment was carried out to investigate the biology of salmonella pullorum in two varieties of laying hens, from 5 days of age up to 9 months. one variety was resistant to systemic salmonellosis (light layers producing white eggs) and the other was considered susceptible (brown layers producing brown eggs). the brown birds were more affected by the infection, showing signs of clinical disease in the first month of life. later, these signs disappeared, but postmortem examination revealed per ... | 2001 | 19184886 |
| pathogenicity of salmonella enteritidis phage types 4, 8 and 23 in specific pathogen free chicks. | the pathogenicity of two isolates of salmonella enterica serovar enteritidis (se) phage type (pt) 4, three of pt8 and one of pt23 was investigated in groups of 1-day-old specific pathogen free white leghorn chicks. two groups were crop gavaged with each culture but at two different doses. two additional groups were given salmonella enterica serovar pullorum (sp) at similar doses and one further group served as uninoculated controls. body weights were recorded at 14, 21, and 28 days postinoculati ... | 2000 | 19184855 |
| evaluation of the effect of mannan-oligosaccharides on the competitive exclusion of salmonella enteritidis colonization in broiler chicks. | this study evaluated the protection against colonization by salmonella enterica serovar enteritidis in the chick's caecum when dosed with caecal contents from hens fed dietary carbohydrates based on mannose. protection was investigated by comparing the effects of four suspensions of hen caecal contents (hcc) fed diets supplemented with 2.5% d -mannose (man-hcc), 2.5% mannoseoligosaccharide (mos-hcc), 2.5% palm kernel meal (pkm-hcc) or unsupplemented mash (mashhcc). four trials to quantify and co ... | 2000 | 19184854 |
| protection against experimental fowl typhoid by parenteral administration of live sl5828, an aroa-serc (aromatic dependent) mutant of a wild-type salmonella gallinarum strain made lysogenic for p22 sie. | a wild-type strain of salmonella enterica serotype gallinarum, lysogenized with p22 sie (superinfection-exclusion defective) was greatly attenuated for newly hatched or 21-day-old chickens. an aroa transductant of the lysogenic strain and an aroa-serc tetracycline-sensitive deletion or deletioninversion mutant of the latter were equally attenuated. intramuscular administration of the aroa-serc strain to 21-day-old chickens protected them against oral challenge with 10(6) colony forming units of ... | 2000 | 19184834 |
| salmonella enterica serotype typhimurium std fimbriae bind terminal alpha(1,2)fucose residues in the cecal mucosa. | the std operon encodes a fimbrial adhesin of salmonella enterica serotype typhimurium that is required for attachment to intestinal epithelial cells and for cecal colonization in the mouse. to study the mechanism by which this virulence factor contributes to colonization we characterized its binding specificity. std-mediated binding to human colonic epithelial (caco-2) cells could be abrogated by removing n-linked glycans. adherence of std fimbriated s. typhimurium to caco-2 cells could be block ... | 2009 | 19183274 |
| inc a/c plasmids are prevalent in multidrug-resistant salmonella enterica isolates. | bacterial plasmids are fragments of extrachromosomal double-stranded dna that can contain a variety of genes that are beneficial to the host organism, like those responsible for antimicrobial resistance. the objective of this study was to characterize a collection of 437 salmonella enterica isolates from different animal sources for their antimicrobial resistance phenotypes and plasmid replicon types and, in some cases, by pulsed-field gel electrophoresis (pfge) in an effort to learn more about ... | 2009 | 19181840 |
| effect of hemidesmus indicus r.br. root extract against salmonella enterica serovar typhimurium-induced apoptosis in murine macrophage cell line (p388d1). | previous studies on natural products had mainly dealt with their antimicrobial activity and studies on the interference of these bioactive compounds with host-bacterial interaction is limited. the present study was undertaken to investigate the effect of the sterols and fatty acids present in the chloroform fraction of crude methanol extract of hemidesmus indicus root (chi) on salmonella enterica serovar typhimurium (s. typhimurium) mediated apoptosis in a murine macrophage cell line (p388d1). | 2008 | 19179687 |
| anthrax protective antigen delivered by salmonella enterica serovar typhi ty21a protects mice from a lethal anthrax spore challenge. | bacillus anthracis, the etiological agent of anthrax disease, is a proven weapon of bioterrorism. currently, the only licensed vaccine against anthrax in the united states is ava biothrax, which, although efficacious, suffers from several limitations. this vaccine requires six injectable doses over 18 months to stimulate protective immunity, requires a cold chain for storage, and in many cases has been associated with adverse effects. in this study, we modified the b. anthracis protective antige ... | 2009 | 19179420 |
| [application of pulsed-field gel electrophoresis in a food-borne outbreak of salmonella serotype muenchen infection]. | to investigate the application of pulsed-field gel electrophoresis (pfge) in food-borne outbreak. | 2008 | 19176144 |
| occurrence of extended-spectrum beta-lactamase-producing salmonella enterica in northern spain with evidence of ctx-m-9 clonal spread among animals and humans. | among the 1233 salmonella enterica isolates obtained in two spanish hospitals, five isolates (0.4%) (serovars: virchow, four; livingstone, one) had the phenotype of an extended-spectrum beta-lactamase (esbl) producer. the genetic characterization of the esbl of s. enterica livingstone revealed a bla(shv-2) gene. the bla(ctx-m-10) gene in a phage-related genetic environment was found in one s. enterica virchow isolate, and the bla(ctx-m-9) gene within the in60 integron was found in the three rema ... | 2009 | 19175621 |
| prevalence and risk factors for bacterial food-borne zoonotic hazards in slaughter pigs: a review. | the hygiene package and regulation ec-2160/2003 require information flow from farm to slaughterhouse to enhance european consumers protection in a 'farm to fork' approach. this obligation especially concerns food-borne zoonotic hazards transmitted to humans through pork consumption, such as thermophilic campylobacter spp., listeria monocytogenes, salmonella enterica and yersinia enterocolitica. prevalence estimates of these four hazards are affected by the sampling strategy and diagnostic proced ... | 2009 | 19175574 |
| [mechanism of interaction of tumor necrosis factor (tnf-alpha) of macroorganism with the salmonella enterica cells (ser. typhimurium)]. | the goal of this work was to elucidate the mechanism of direct interaction of bacterial cells with tumor necrosis factor (tnf-alpha; cytokine). it was shown earlier that this interaction facilitated activation of bacterial growth and recultivation of non-cultivated forms in vitro and in vivo. it was shown in experiments with mice deficient in the genes encoding eucaryotic tnf-alpha receptors and infected with salmonella that addition of exogenous tnf-alpha to suspension of infection cells caused ... | 2008 | 19172874 |
| isolation of salmonella enterica serotype isangi from a suspected case of enteric encephalopathy. | nontyphoidal salmonella species are thought to be potentially infectious to humans and many are documented to cause human diseases. we isolated s. isangi from the blood of a 30-year-old man with complaints of diarrhoea, fever, and altered sensorium. the serotype of the isolate was confirmed at national salmonella centre (vet.), division of bacteriology and mycology, indian veterinary research institute, izzatnagar, india. the isolate was not an extended spectrum beta-lactamase (esbl) producer an ... | 2009 | 19172065 |
| acid stress activation of the sigma(e) stress response in salmonella enterica serovar typhimurium. | the alternative sigma factor sigma(e) is activated by unfolded outer membrane proteins (omps) and plays an essential role in salmonella pathogenesis. the canonical pathway of sigma(e) activation in response to envelope stress involves sequential proteolysis of the anti-sigma factor rsea by the pdz proteases degs and rsep. here we show that sigma(e) in salmonella enterica sv. typhimurium can also be activated by acid stress. a sigma(e)-deficient mutant exhibits increased susceptibility to acid ph ... | 2009 | 19170886 |
| sequence analysis of the plasmid pgy1 harbored in salmonella enterica serovar paratyphi a. | the cryptic plasmid pgy1, which is harbored by a clinical isolate of salmonella enterica serovar paratyphi a, was identified in a 9-year-old girl with paratyphoid fever in 2005, and its dna sequence was determined. it is 3592 bp in length and had a g+c content of 43.3%. three orfs were predicted that share low similarity with hypothetical proteins in the genbank database. pgy1 shared 36.6% sequence homology with the cryptic plasmid pimvs1 from salmonella typhimurium. its unique sequence makes it ... | 2009 | 19169860 |
| salmonella enterica serovar typhimurium mutants unable to convert malate to pyruvate and oxaloacetate are avirulent and immunogenic in balb/c mice. | previously, we showed that the salmonella enterica serovar typhimurium sr-11 tricarboxylic acid (tca) cycle must operate as a complete cycle for full virulence after oral infection of balb/c mice (m. tchawa yimga, m. p. leatham, j. h. allen, d. c. laux, t. conway, and p. s. cohen, infect. immun. 74:1130-1140, 2006). in the same study, we showed that for full virulence, malate must be converted to both oxaloacetate and pyruvate. moreover, it was recently demonstrated that blocking conversion of s ... | 2009 | 19168732 |
| the salmonella pathogenicity island 2-encoded type iii secretion system is essential for the survival of salmonella enterica serovar typhimurium in free-living amoebae. | free-living amoebae represent a potential reservoir and predator of salmonella enterica. through the use of type iii secretion system (t3ss) mutants and analysis of transcription of selected t3ss genes, we demonstrated that the salmonella pathogenicity island 2 is highly induced during s. enterica serovar typhimurium infection of acanthamoeba polyphaga and is essential for survival within amoebae. | 2009 | 19168655 |
| pseudogene accumulation in the evolutionary histories of salmonella enterica serovars paratyphi a and typhi. | of the > 2000 serovars of salmonella enterica subspecies i, most cause self-limiting gastrointestinal disease in a wide range of mammalian hosts. however, s. enterica serovars typhi and paratyphi a are restricted to the human host and cause the similar systemic diseases typhoid and paratyphoid fever. genome sequence similarity between paratyphi a and typhi has been attributed to convergent evolution via relatively recent recombination of a quarter of their genomes. the accumulation of pseudogene ... | 2009 | 19159446 |
| rapid dna amplification using a battery-powered thin-film resistive thermocycler. | a prototype handheld, compact, rapid thermocycler was developed for multiplex analysis of nucleic acids in an inexpensive, portable configuration. instead of the commonly used peltier heating/cooling element, electric thin-film resistive heater and a miniature fan enable rapid heating and cooling of glass capillaries leading to a simple, low-cost thin-film resistive thermocycler (tfrt). computer-based pulse width modulation control yields heating rates of 6-7 k/s and cooling rates of 5 k/s. the ... | 2009 | 19159110 |
| studying the mechanism of rna separations using rna chromatography and its application in the analysis of ribosomal rna and rna:rna interactions. | dna/rna chromatography presents a versatile platform for the analysis of nucleic acids. although the mechanism of separation of double stranded (ds) dna fragments is largely understood, the mechanism by which rna is separated appears more complicated. to further understand the separation mechanisms of rna using ion pair reverse phase liquid chromatography, we have analysed a number of dsrna and single stranded (ss) rna fragments. the high-resolution separation of dsrna was observed, in a similar ... | 2009 | 19155018 |
| evaluation of the bacterial diversity in cecal contents of laying hens fed various molting diets by using bacterial tag-encoded flx amplicon pyrosequencing. | laying hens are typically induced to molt to begin a new egg-laying cycle by withdrawing feed for up to 12 to 14 d. fasted hens are more susceptible to colonization and tissue invasion by salmonella enterica serovar enteritidis. much of this increased incidence in fasted hens is thought to be due to changes in the native intestinal microflora. an alternative to feed withdrawal involves feeding alfalfa meal crumble to hens, which is indigestible by poultry but provides fermentable substrate to th ... | 2009 | 19151343 |
| rapid oligonucleotide-based recombineering of the chromosome of salmonella enterica. | recombinant engineering using red recombinase-based approaches offers efficient and rapid approaches to deletion and modification of genes. here we describe a novel application of red recombinant engineering that enables direct manipulation of chromosomal loci by electroporation with short synthetic dna molecules. we demonstrate the use of this approach for the generation of scarless in-frame deletions in chromosomal genes of salmonella enterica. furthermore, we describe rapid site-directed muta ... | 2009 | 19151186 |
| comparative structural and molecular characterization of ribitol-5-phosphate-containing streptococcus oralis coaggregation receptor polysaccharides. | the antigenically related coaggregation receptor polysaccharides (rps) of streptococcus oralis strains c104 and sk144 mediate recognition of these bacteria by other members of the dental plaque biofilm community. in the present study, the structure of strain sk144 rps was established by high resolution nmr spectroscopy as [6galfbeta1-6galnacbeta1-3galalpha1-2ribitol-5-po(4)(-)-6galfbeta1-3galbeta1](n), thereby indicating that this polysaccharide and the previously characterized rps of strain c10 ... | 2009 | 19151140 |
| rapid real-time pcr assay for detecting salmonella in raw and ready-to-eat meats. | a real-time pcr assay was evaluated for the rapid detection (10 h) of salmonella in meats using molecular beacon probes available as a commercial kit (iq-check, bio-rad laboratories). raw (chicken, pork) and ready-to-eat (rte) meats were artificially contaminated with salmonella enterica serovar typhimurium at the estimated level of 2 to 4 cells per 25 g. after 8 h of pre-enrichment in buffered peptone water, a molecular beacon-based pcr assay was performed to detect contamination in raw and rte ... | 2008 | 19149100 |
| typhoid rhabdomyolysis with acute renal failure and acute pancreatitis: a case report and review of the literature. | we report a case of typhoid rhabdomyolysis with acute renal failure and acute pancreatitis in a 23-year-old vietnamese male who was admitted to the intensive care unit with a 15-day history of fever followed by severe abdominal pain. on examination, the patient was febrile and his abdomen was diffusely tender. serum creatinine was 533 micromol/l, pancreatic amylase 1800 u/l and lipase 900 u/l; the myoglobin blood level was high, which is associated with significant myoglobinuria. blood, urine an ... | 2009 | 19147385 |
| effects of repeated cycles of acid challenge and growth on the phenotype and virulence of salmonella enterica. | the aim of the study was to investigate how stresses like low ph, which may be encountered in farms or food preparation premises, shape populations of salmonella enterica by the selection of stress-resistant variants. | 2008 | 19146498 |
| transmission of salmonella between wildlife and meat-production animals in denmark. | to investigate the transmission of salmonella spp. between production animals (pigs and cattle) and wildlife on production animal farms in denmark. | 2008 | 19146492 |
| [report on typhoid fever case in maringá, state of paraná]. | typhoid fever is an acute bacterial disease caused by salmonella enterica serotype typhi, which is acquired by consumption of contaminated food or water. this paper had the aim of describing a case of typhoid fever that occurred in maringá, state of paraná, after three years without any notifications of the disease. | 2008 | 19142452 |
| recovery of salmonella from bermudagrass exposed to simulated wastewater. | most confined swine (sus scrofa) feeding operations in the southeastern united states hold manure in lagoons and apply effluent on bermudagrass [cynodon dactylon (l.) pers.] as fertilizer. salmonella enterica subsp. enterica (ex kauffman and edwards) le minor and popoff, has been reported in mississippi lagoons, but levels and potential for contamination of bermudagrass were unknown. a laboratory method was developed to examine salmonella contamination of bermudagrass and levels of salmonella we ... | 2009 | 19141824 |
| campylobacter jejuni drives myd88-independent interleukin-6 secretion via toll-like receptor 2. | gastrointestinal disease caused by campylobacter jejuni is characterized by localized inflammation and the destruction of the epithelial cell barrier that forms host innate protection against pathogens. this can lead to an imbalance in fluid transport across the gastrointestinal tract, resulting in severe diarrhea. the mechanisms of host cell receptor recognition of c. jejuni and downstream immune signaling pathways leading to this inflammatory disease, however, remain unclear. the aim of this s ... | 2009 | 19139198 |
| the proteome of salmonella typhimurium grown under in vivo-mimicking conditions. | to successfully infect a host, it is a prerequisite for enteric pathogens such as salmonella enterica serovar typhimurium to adapt to their environment, in casu the gastrointestinal tract. the adoption of an appropriate lifestyle is triggered by environmental signals such as the low oxygen availability and high osmolarity prevalent in the gut. in order to gain more insight in the changes that are induced when s. typhimurium is adapting to these particular conditions, we used 2-d dige technology ... | 2009 | 19137547 |
| involvement of the cra global regulatory protein in the expression of the iscrsua operon, revealed during studies of tricarballylate catabolism in salmonella enterica. | in salmonella enterica, tricarballylate (tcb) catabolism requires function of tcub, a membrane-bound protein that contains [4fe-4s] clusters and heme. tcub transfers electrons from reduced flavin adenine dinucleotide in the tcb dehydrogenase (tcua) to electron acceptors in the membrane. we recently showed that functions needed to assemble [fe-s] clusters (i.e., the iscrsua-hscba-fdx operon) compensate for the lack of apbc during growth of an apbc strain on tcb. apbc had been linked to [fe-s] clu ... | 2009 | 19136587 |
| is rotavirus contributing to an increase of diarrhoea in a region of spain? | diarrhoeal illnesses are the most frequent of notifiable diseases in aragon. physicians notify diarrhoea cases with presumed infectious origin on a weekly basis. following an increase in 2005-2006, we aimed to identify the responsible organism(s) in order to inform control measures. we described seasonality of diarrhoea notifications for 1998-2004 and 2005-2006. we calculated correlations between diarrhoea notifications and enteric pathogens diagnosed in two aragonese laboratories, and applied l ... | 2009 | 19134236 |
| tlr2 and tlr4 signaling shapes specific antibody responses to salmonella typhi antigens. | tlr directly induce innate immune responses by sensing a variety of microbial components and are critical for the fine-tuning of subsequent adaptive immune responses. however, their impact and mechanism of action on antibody responses against bacterial antigens are not yet fully understood. salmonella enterica serovar typhi (s. typhi) porins have been characterized as inducers of long-lasting specific antibody responses in mice. in this report, we show that immunization of tlr4-deficient (tlr4(- ... | 2009 | 19130558 |
| a sensitive liquid chromatography/mass spectrometry-based assay for quantitation of amino-containing moieties in lipid a. | a novel sensitive liquid chromatography/mass spectrometry-based assay was developed for the quantitation of aminosugars, including 2-amino-2-deoxyglucose (glucosamine, glcn), 2-amino-2-deoxygalactose (galactosamine, galn), and 4-amino-4-deoxyarabinose (aminoarabinose, aran), and for ethanolamine (etn), present in lipid a. this assay enables the identification and quantitation of all amino-containing moieties present in lipopolysaccharide or lipid a from a single sample. the method was applied to ... | 2009 | 19130491 |
| discovery of novel 2',3',4'-trihydroxy-2-phenylacetophenone derivatives as anti-gram-positive antibacterial agents. | a number of 2',3',4'-trihydroxy-2-phenylacetophenone derivatives were synthesized and examined for growth inhibition of several kinds of bacteria. 2',3',4'-trihydroxy-2-phenylacetophenone itself exhibited no antibacterial activity, but some of its derivatives showed various antibacterial activities depending on functional groups introduced on the 2-phenyl ring. eighteen out of 24 compounds synthesized in this study appeared to possess antibacterial activities against at least two gram-positive s ... | 2009 | 19129641 |
| bacterial particle endocytosis by epithelial cells is selective and enhanced by tumor necrosis factor receptor ligands. | bacterial pathogens use virulence strategies to invade epithelial barriers, but active processes of epithelial cells may also contribute to the endocytosis of microbial particles. to focus on the latter, we studied the uptake of fixed and fluorescently labeled bacterial particles in intestinal and bronchoepithelial cell cultures and found it to be enhanced in caco-2bbe and nci-h292 cells after treatment with tumor necrosis factor alpha and an agonist antibody against the lymphotoxin beta recepto ... | 2009 | 19129472 |
| changes in antimicrobial resistance among salmonella enterica subspecies enterica serovar pullorum isolates in china from 1962 to 2007. | there are few data available for the trends of antimicrobial resistance of salmonella enterica subspecies enterica serovar pullorum (s. pullorum) in china and other parts of the world. thus, the objective of this study was to evaluate the changes in antimicrobial resistance of s. pullorum isolated from diseased chickens in china from 1962 to 2007. a total of 450 s. pullorum isolates were tested for their susceptibility to 17 antimicrobials in a disk diffusion method. 39-95% of the isolates displ ... | 2009 | 19128897 |
| distribution of antibody titer against salmonella enterica among healthy individuals in nepal. | enteric fever is an endemic problem in nepal and widal agglutination test is widely used for its diagnosis but a normal baseline titer in healthy population and cutoff values have not been established. | 2009 | 19128506 |
| structural and functional analysis of the c-terminal dna binding domain of the salmonella typhimurium spi-2 response regulator ssrb. | in bacterial pathogenesis, virulence gene regulation is controlled by two-component regulatory systems. in escherichia coli, the envz/ompr two-component system is best understood as regulating expression of outer membrane proteins, but in salmonella enterica, ompr activates transcription of the ssra/b two-component system located on salmonella pathogenicity island 2 (spi-2). the response regulator ssrb controls expression of a type iii secretory system in which effectors modify the vacuolar memb ... | 2009 | 19126546 |
| the salmonella pathogenicity island (spi) 1 contributes more than spi2 to the colonization of the chicken by salmonella enterica serovar typhimurium. | salmonella enterica serovar typhimurium (typhimurium) is an important pathogen that infects a broad range of hosts. in humans, typhimurium causes a gastroenteritis characterized by vomiting, diarrhea, and abdominal pains. typhimurium infection occurs mainly through the ingestion of contaminated food including poultry, pork, eggs, and milk. chickens that are asymptomatic carriers of typhimurium constitute a potential reservoir for infection. the type three secretion systems encoded by salmonella ... | 2009 | 19126220 |
| interleukin-17 in host defence against bacterial, mycobacterial and fungal pathogens. | the mammalian immune system is intricately regulated, allowing for potent pathogen-specific immunity to be rapidly activated in response to infection with a broad and diverse array of potential pathogens. as a result of their ability to differentiate into distinct effector lineages, cd4 t cells significantly contribute to pathogen-specific adaptive immune responses. through the production of effector cytokines, cd4 t helper (th) cells orchestrate the precise mobilization of specific immune cells ... | 2009 | 19125888 |
| distribution, diversity, and seasonality of waterborne salmonellae in a rural watershed. | salmonella outbreaks from contaminated water and nonanimal foods (e.g., produce) are increasingly reported. to address the environment as a potential source of pathogenic salmonella, we investigated levels of salmonellae and the geographic and temporal variation of salmonella serotypes from surface waters in a region of georgia (united states) with a history of high salmonellosis case rates. monthly water samples were collected from six stations in the little river (upper suwannee basin) for 12 ... | 2009 | 19124594 |
| characterization of a monoclonal antibody directed against salmonella enterica serovar typhimurium and serovar [4,5,12:i:-]. | flagellar extracts of salmonella enterica serovars expressing phase 2 h1 antigenic complex (h:1,2, h:1,5, h:1,6, and h:1,7) and a mutant flagellin obtained by site-directed mutagenesis of the fljb gene from serovar typhimurium at codon 218, transforming threonine to alanine, expressed in escherichia coli (fljb218(a)) were used to analyze the h1 antigenic complex. cross-reactions were detected by western blotting and dot blotting using commercial polyclonal antibodies against the different wild-t ... | 2009 | 19124586 |
| genome expression analyses revealing the modulation of the salmonella rcs regulon by the attenuator igaa. | intracellular growth attenuator a (igaa) was identified as a salmonella enterica regulator limiting bacterial growth inside fibroblasts. genetic evidence further linked igaa to repression of the rcscdb regulatory system, which responds to envelope stress. how igaa attenuates this system is unknown. here, we present genome expression profiling data of s. enterica serovar typhimurium igaa mutants grown at high osmolarity and displaying exacerbated rcs responses. transcriptome data revealed that ig ... | 2009 | 19124574 |
| phage type and antimicrobial susceptibility of salmonella enterica serovar enteritidis from food-producing animals in japan between 1976 and 2004. | a total of 56 isolates of salmonella enterica serovar enteritidis, including 38 isolates from poultry, 16 from cattle and two from pigs, collected between 1976 and 2004, were subjected to bacteriophage typing and antimicrobial susceptibility testing. phage type (pt) 8 was predominant in bovine isolates, whereas pt1 and pt4 were predominant in poultry isolates. resistance was found for 8 of 11 antimicrobials tested, at the following rates: 46.4% for dihydrostreptomycin followed by ampicillin and ... | 2008 | 19123313 |
| calprotectin s100a9 calcium-binding loops i and ii are essential for keratinocyte resistance to bacterial invasion. | epithelial cells expressing calprotectin, a heterodimer of s100a8 and s100a9 proteins, are more resistant to bacterial invasion. to determine structural motifs that affect resistance to bacterial invasion, mutations were constructed in s100a9 targeting the calcium-binding loops i and ii (e36q, e78q, e36q,e78q) and the c terminus (s100a9(1-99) and s100a9(1-112)), which contains putative antimicrobial zinc-binding and phosphorylation sites. the s100a8 and mutated s100a9 encoding plasmids were tran ... | 2009 | 19122197 |
| genetic stability of vaccine strain salmonella typhi ty21a over 25 years. | the attenuated live bacterial vaccine strain salmonella enterica serovar typhi ty21a is the main constituent of vivotif, the only licensed oral vaccine against typhoid fever. the strain was developed in the 1970s by chemical mutagenesis. in the course of this mutagenesis, a number of mutations were introduced into the vaccine strain. characterisation of the vaccine strain during development as well as release of master- and working seed lots (msl and wsl) and commercial batches is based on pheno ... | 2009 | 19121604 |
| regulation of mara, soxs, rob, acrab and micf in salmonella enterica serovar typhimurium. | importance of the overexpression of acrab efflux pumps in the low-level resistance of pathogens to antimicrobials requires a better understanding of the acrab regulation. the goal of the present research was to study the transcription of acrab, as well as the genes that play a role in its regulation in salmonella enterica serovar typhimurium. we monitored the transcription of these genes during growth at 30 degrees c and 37 degrees c, and thoroughly studied the effect of salicylate, paraquat and ... | 2008 | 19120970 |
| regulators of g-protein signalling are modulated by bacterial lipopeptides and lipopolysaccharide. | regulators of g-protein signalling accelerate the gtpase activity of g(alpha) subunits, driving g proteins in their inactive gdp-bound form. this property defines them as gtpase activating proteins. here the effect of different toll-like receptor agonists on rgs1 and rgs2 expression in murine bone marrow-derived macrophages and j774 cells was analysed. after stimulation with tlr2/1 or tlr2/6 lipopeptide ligands and the tlr4/md2 ligand lipopolysaccharide, microarray analyses show only modulation ... | 2009 | 19120454 |
| evaluation of the control of pathogen load by an anti-salmonella bacterium in a herd of cattle with persistent salmonella infection. | to determine whether an anti-salmonella bacterium is involved in control of pathogen load in persistently infected cattle herds. | 2009 | 19119953 |
| citrate-mediated iron uptake in pseudomonas aeruginosa: involvement of the citrate-inducible feca receptor and the feob ferrous iron transporter. | in an attempt to identify components of a ferric citrate uptake system in pseudomonas aeruginosa, a mutant library of a siderophore-deficient strain (ia614) was constructed and screened for defects in citrate-promoted growth in an fe-restricted medium. a mutant disrupted in gene pa3901, encoding a homologue of the outer-membrane ferric citrate receptor, feca, of escherichia coli (feca(e.c.)), was recovered and shown to be deficient in citrate-promoted growth and citrate-mediated fe uptake. a mut ... | 2009 | 19118371 |
| oxidative stress and disruption of labile iron generate specific auxotrophic requirements in salmonella enterica. | the response of a cell to integrated stresses was investigated using environmental and/or genetic perturbations that disrupted labile iron homeostasis and increased oxidative stress. the effects of the perturbations were monitored as nutritional requirements, and were traced to specific enzymic targets. a yggx gsha cyay mutant strain required exogenous thiamine and methionine for growth. the thiamine requirement, which had previously been linked to the fe-s cluster proteins thih and thic, was re ... | 2009 | 19118370 |
| osmoregulated periplasmic glucans of salmonella enterica serovar typhimurium are required for optimal virulence in mice. | we purified osmoregulated periplasmic glucans (opgs) from salmonella enterica serovar typhimurium and found them to be composed of 100 % glucose with 2-linked glucose as the most abundant residue, with terminal glucose, 2,3-linked and 2,6-linked glucose also present in high quantities. the two structural genes for opg biosynthesis, opgg and opgh, form a bicistronic operon, and insertion of a kanamycin resistance gene cassette into this operon resulted in a strain devoid of opgs. the opggh mutant ... | 2009 | 19118363 |
| deletion of tola in salmonella typhimurium generates an attenuated strain with vaccine potential. | the gram-negative tol-pal system of envelope proteins plays a key role in maintaining outer membrane integrity and contributes to the virulence of several pathogens. we have investigated the role of one of these proteins, tola, in the biology of salmonella enterica serovar typhimurium. deletion of tola rendered strain sl1344 more susceptible to killing by bile and human serum. in addition the mutant had impaired membrane integrity and displayed alterations in lps production. the tola mutant was ... | 2009 | 19118362 |
| variation in antimicrobial resistance in sporadic and outbreak-related salmonella enterica serovar typhimurium. | the prevalence of different antimicrobial resistance profiles and variants of the salmonella genomic island 1 (sgi1) was reported for salmonella enterica serovar typhimurium dt104 strains isolated from patients in denmark. variation in antimicrobial resistance and corresponding changes of sgi1 were shown among isolates from a foodborne outbreak. | 2009 | 19116064 |
| evaluation of new generation salmonella enterica serovar typhimurium vaccines with regulated delayed attenuation to induce immune responses against pspa. | increasing the immunogenicity to delivered antigens by recombinant attenuated salmonella vaccines (rasv) has been the subject of intensive study. with this goal in mind, we have designed and constructed a new generation of rasv that exhibit regulated delayed attenuation. these vaccine strains are phenotypically wild type at the time of immunization and become attenuated after colonization of host tissues. the vaccine strains are grown under conditions that allow expression of genes required for ... | 2009 | 19114649 |
| poultry-associated salmonella enterica subsp. enterica serovar 4,12:d:- reveals high clonality and a distinct pathogenicity gene repertoire. | a european baseline survey during the years 2005 and 2006 has revealed that the monophasic salmonella enterica subsp. enterica serovar 4,12:d:- was, with a prevalence of 23.6%, the most frequently isolated serovar in german broiler flocks. in denmark and the united kingdom, its serovar prevalences were 15.15% and 2.8%, respectively. although poultry is a major source of human salmonellosis, serovar 4,12:d:- is rarely isolated in humans (approximately 0.09% per year). molecular typing studies usi ... | 2009 | 19114530 |
| role of the hya hydrogenase in recycling of anaerobically produced h2 in salmonella enterica serovar typhimurium. | double and triple uptake-type hydrogenase mutants were used to determine which hydrogenase recycles fermentatively produced hydrogen. the deltahyb deltahya and deltahyd deltahya double mutants evolved h(2) at rates similar to that of the triple mutant strain, so hya alone oxidizes the bulk of h(2) produced during fermentation. when only hya was present, no hydrogen production was observed in nutrient-limited medium. h(2) uptake assays showed that hya can oxidize both exogenously added h(2) and f ... | 2009 | 19114523 |
| archaeal apbc/nbp35 homologs function as iron-sulfur cluster carrier proteins. | iron-sulfur clusters may have been the earliest catalytic cofactors on earth, and most modern organisms use them extensively. although members of the archaea produce numerous iron-sulfur proteins, the major cluster assembly proteins found in the bacteria and eukarya are not universally conserved in archaea. free-living archaea do have homologs of the bacterial apbc and eukaryotic nbp35 genes that encode iron-sulfur cluster carrier proteins. this study exploits the genetic system of salmonella en ... | 2009 | 19114487 |