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hr-mas nmr reveals a ph-dependent lps alteration by de-o-acetylation at abequose in the o-antigen of salmonella enterica serovar typhimurium.nmr spectroscopy can detect biomolecules like lipopolysaccharide directly on the surface of the cell, thus avoiding isolation and purification, and providing a more realistic description than the one derived from in vitro studies. here we present a high-resolution magic-angle spinning nmr study of the o-antigen of salmonella enterica serovar typhimurium (s. typhimurium) performed directly on the cells showing the alteration of its acetylation state over time. the o-antigen region of s. typhimuri ...201324211643
evaluation of genotoxic effects of new molecules with possible trypanocidal activity for chagas disease treatment.chagas disease is responsible for a large number of human infections and many are also at risk of infection. there is no effective drug for chagas disease treatment. the institute of pharmaceutical technology at fiocruz, brazil, has designed three nitro analogs of the nitroimidazole-thiadiazole, megazol: two triazole analogs ptal 05-02 and pamt 09 and a pyrazole analog ptal 04-09. a set of salmonella enterica serovar typhimurium strains were used in the bacterial reverse mutation test (ames test ...201324311974
pyroptosis and adaptive immunity mechanisms are promptly engendered in mesenteric lymph-nodes during pig infections with salmonella enterica serovar typhimurium.in this study, we explored the transcriptional response and the morphological changes occurring in porcine mesenteric lymph-nodes (mln) along a time course of 1, 2 and 6 days post infection (dpi) with salmonella typhimurium. additionally, we analysed the expression of some salmonella effectors in tissue to complete our view of the processes triggered in these organs upon infection. the results indicate that besides dampening apoptosis, swine take advantage of the flagellin and prgj expression by ...201324308825
salmonella neck abscess as an opportunistic infection in diabetes mellitus.salmonella neck infections represent an uncommon cause of focal salmonellosis. while the incidence of nontyphoid salmonellosis is estimated at over 2 million cases annually, extraintestinal manifestations account for less than 1% of cases. this paper describes two patients with salmonella neck abscesses as the initial presentation of diabetes mellitus. the first patient was diagnosed as having salmonella enterica serotype enteritidis sternocleidomastoid pyomyositis and the second patient salmone ...201324307959
a link between gut community metabolism and pathogenesis: molecular hydrogen-stimulated glucarate catabolism aids salmonella virulence.glucarate, an oxidized product of glucose, is a major serum organic acid in humans. still, its role as a carbon source for a pathogen colonizing hosts has not been studied. we detected high-level expression of a potential glucarate permease encoding gene gudt when salmonella enterica serovar typhimurium are exposed to hydrogen gas (h(2)), a gaseous by-product of gut commensal metabolism. a gudt strain of salmonella is deficient in glucarate-dependent growth, however, it can still use other monos ...201324307595
an infection-relevant transcriptomic compendium for salmonella enterica serovar typhimurium.bacterial transcriptional networks consist of hundreds of transcription factors and thousands of promoters. however, the true complexity of transcription in a bacterial pathogen and the effect of the environments encountered during infection remain to be established. we present a simplified approach for global promoter identification in bacteria using rna-seq-based transcriptomic analyses of 22 distinct infection-relevant environmental conditions. individual rna samples were combined to identify ...201324331466
non-essential genes form the hubs of genome scale protein function and environmental gene expression networks in salmonella enterica serovar typhimurium.salmonella typhimurium is an important pathogen of human and animals. it shows a broad growth range and survives in harsh conditions. the aim of this study was to analyze transcriptional responses to a number of growth and stress conditions as well as the relationship of metabolic pathways and/or cell functions at the genome-scale-level by network analysis, and further to explore whether highly connected genes (hubs) in these networks were essential for growth, stress adaptation and virulence.201324345035
ifnγ expression by an attenuated strain of salmonella enterica serovar typhimurium improves vaccine efficacy in susceptible tlr4-defective c3h/hej mice.c3h/hej mice carry a mutated allele of tlr4 gene (tlr4 ( d )) and thus are hyporesponsive to the lethal effects of lipopolysaccharide (lps). characteristically, however, the mice are also hypersusceptible to infections, particularly by gram-negative bacteria such as salmonella enterica serovar typhimurium (s. typhimurium) and are known to be difficult to vaccinate against virulent exposure. this is observed despite the expression of wild-type allele of nramp1 gene, another important determinant ...201322684724
[model of chronic salmonellosis: parameters of infection and immune response in inbred mice genetically variable in susceptibility to salmonellosis].study parameters of chronic infection and immune response in i/st and a/sn line mice in the model of per oral infection of mice with salmonella enterica serovar typhimurium.201322937698
phenotypic analysis of salmonella enterica serovar typhimurium rpoe mutants encoding rna polymerase extracytoplasmic stress response sigma factors σ(e) with altered promoter specificity.we previously identified mutants in the rpoe gene of salmonella enterica serovar typhimurium (s. typhimurium) encoding rna polymerase extracytoplasmic stress response sigma factors σ(e) with altered promoter specificity. the replacement of the conserved r171 residue in the conserved region 4.2 of σ(e) by different amino acid residues exhibited different phenotypes. while r171a almost completely abolished sigma factor activity, r171g and r171c mutant changes imparted a relaxed recognition phenoty ...201322972381
impact of maternally-derived antibodies against salmonella enterica serovar typhimurium on the bacterial load in suckling piglets.the significance of maternal immunity against non-typhoid salmonella spp. acquired by piglets via colostrum and milk was evaluated in a salmonella enterica serovar typhimurium challenge experiment. piglets from sows vaccinated with an experimental inactivated vaccine exhibited high levels of serum immunoglobulins g and a against s. typhimurium 4 days after birth, just prior to experimental oral challenge. the s. typhimurium load in the ileal and caecal wall of piglets 3 days after experimental i ...201322967925
differential outcome of infection with attenuated salmonella in myd88-deficient mice is dependent on the route of administration.activation of the innate immune system is a prerequisite for the induction of adaptive immunity to both infectious and non-infectious agents. tlrs are key components of the innate immune recognition system and detect pathogen-associated molecular patterns. most tlrs utilize the myd88 adaptor for their signaling pathways. in the current study, we investigated innate and adaptive immune responses to primary as well as secondary salmonella infections in myd88-deficient (myd88(-/-)) mice. using i.p. ...201322386951
electrochemical detection of salmonella using gold nanoparticles.a disposable immunosensor for salmonella enterica subsp. enterica serovar typhimurium lt2 (s) detection using a magneto-immunoassay and gold nanoparticles (aunps) as label for electrochemical detection is developed. the immunosensor is based on the use of a screen-printed carbon electrode (spce) that incorporates a permanent magnet underneath. salmonella containing samples (i.e. skimmed milk) have been tested by using anti-salmonella magnetic beads (mbs-psab) as capture phase and sandwiching aft ...201322884647
genome scanning for conditionally essential genes in salmonella enterica serotype typhimurium.as more whole-genome sequences become available, there is an increasing demand for high-throughput methods that link genes to phenotypes, facilitating discovery of new gene functions. in this study, we describe a new version of the tn-seq method involving a modified ez:tn5 transposon for genome-wide and quantitative mapping of all insertions in a complex mutant library utilizing massively parallel illumina sequencing. this tn-seq method was applied to a genome-saturating salmonella enterica sero ...201222367088
a third mode of surface-associated growth: immobilization of salmonella enterica serovar typhimurium modulates the rpos-directed transcriptional programme.although the growth of bacteria has been studied for more than a century, it is only in recent decades that surface-associated growth has received attention. in addition to the well-characterized biofilm and swarming lifestyles, bacteria can also develop as micro-colonies supported by structured environments in both food products and the gi tract. this immobilized mode of growth has not been widely studied. to develop our understanding of the effects of immobilization upon a food-borne bacterial ...201222356617
laboratory-based surveillance of non-typhoidal salmonella infections in guangdong province, china.salmonella is one of the most common foodborne pathogens in humans. laboratory-based surveillance for non-typhoidal salmonella infection was conducted in guangdong province, china to improve understanding about the disease burden and detection of dispersed outbreaks. salmonella isolated from patients with diarrhea were sent from 16 sentinel hospitals to local public health laboratories for confirmation, serotyping, antimicrobial susceptibility testing, and pulsed-field gel electrophoresis (pfge) ...201222356574
peroral ciprofloxacin therapy impairs the generation of a protective immune response in a mouse model for salmonella enterica serovar typhimurium diarrhea, while parenteral ceftriaxone therapy does not.nontyphoidal salmonella (nts) species cause self-limiting diarrhea and sometimes severe disease. antibiotic treatment is considered only in severe cases and immune-compromised patients. the beneficial effects of antibiotic therapy and the consequences for adaptive immune responses are not well understood. we used a mouse model for salmonella diarrhea to assess the effects of per os treatment with ciprofloxacin (15 mg/kg of body weight intragastrically 2 times/day, 5 days) or parenteral ceftriaxo ...201222354292
igg keeps virulent salmonella from evading dendritic cell uptake.dendritic cells (dcs) are phagocytic professional antigen-presenting cells that can prime naive t cells and initiate anti-bacterial immunity. however, several pathogenic bacteria have developed virulence mechanisms to impair dc function. for instance, salmonella enterica serovar typhimurium can prevent dcs from activating antigen-specific t cells. in addition, it has been described that the salmonella pathogenicity island 1 (spi-1), which promotes phagocytosis of bacteria in non-phagocytic cells ...201222352313
hfq and hfq-dependent small rnas are major contributors to multicellular development in salmonella enterica serovar typhimurium.the rna chaperone hfq and its associated small rnas (srnas) regulate a variety of phenotypes in bacteria. in this work, we show that hfq is a master regulator of biofilm formation in salmonella enterica serovar typhimurium. hfq and two hfq-dependent srnas (arcz and sdsr) are required for rdar morphotype expression in s. typhimurium. hfq controls rdar biofilm formation through the major biofilm regulator csgd. while csgd mrna steady-state levels are altered in a sdsr mutant, arcz seems to work ma ...201222336758
development of carbapenem resistance during therapy for non-typhoid salmonella infection.multidrug-resistant salmonella infection is a global problem, and carbapenems may represent the last therapeutic choice. we report a case of infection caused by ceftriaxone-resistant and ciprofloxacin-resistant salmonella enterica serotype typhimurium. a bla(cmy-2) -containing tn6092, located on a self-transferable inci1 plasmid, was found in all isolates derived from the patient. during ertapenem treatment, the strain developed carbapenem resistance. apart from the ompd deficiency found in all ...201222329543
dksa-dependent resistance of salmonella enterica serovar typhimurium against the antimicrobial activity of inducible nitric oxide synthase.in coordination with the ppgpp alarmone, the rna polymerase regulatory protein dksa controls the stringent response of eubacteria, negatively regulating transcription of translational machinery and directly activating amino acid promoters and de novo amino acid biosynthesis. given the effects of nitric oxide (no) on amino acid biosynthetic pathways and the intimate relationship of dksa with amino acid synthesis and transport, we tested whether dksa contributes to the resistance of salmonella to ...201222311927
the evaluation of clusters of hospital infections due to multidrug-resistant salmonella enterica serovar typhimurium in the neonatal unit: a two-year experience.seven clusters of hospital infection due to salmonella enterica serovar typhimurium were documented in the neonatology clinic of a children's hospital between april 2002 and march 2004. eighty-one neonates were infected. three cases were asymptomatic, 73 cases had gastroenteritis as the only clinical condition, and 5 cases had bacteremia associated with gastroenteritis. all isolates from stool and blood samples (n=86) were identified as salmonella enterica serovar typhimurium. extended-spectrum ...201222272451
proteomic pleiotropy of opggh, an operon necessary for efficient growth of salmonella enterica serovar typhimurium under low-osmotic conditions.salmonella enterica, a bacterial, food-borne pathogen of humans, can contaminate raw fruits and vegetables. unfortunately for consumers, the bacteria can survive in water used to wash away contaminating bacteria. the ability to survive the low-osmotic conditions of the wash water is attributed to the opggh operon that leads to the production of osmotically regulated periplasmic glucans. mutants lacking opggh grow slowly under low-osmotic conditions, but there are also unexpected traits such as a ...201222264073
death receptor 3 is essential for generating optimal protective cd4⁺ t-cell immunity against salmonella.the tnf receptor superfamily member death receptor 3 (dr3) exacerbates th2- and th17-cell-mediated inflammatory and autoimmune conditions, yet no role in host defence has been reported. here, we examined the role of dr3 during infection with salmonella enterica serovar typhimurium. infection resulted in protracted expression of the dr3 ligand tl1a but not the related tnf superfamily proteins ox40l or cd30l. tl1a expression was localized to splenic f4/80(+) macrophages where s. enterica typhimuri ...201222259035
foodborne outbreak and nonmotile salmonella enterica variant, france.we report a food-related outbreak of salmonellosis in humans caused by a nonmotile variant of salmonella enterica serotype typhimurium in france in 2009. this nonmotile variant had been circulating in laying hens but was not considered as typhimurium and consequently escaped european poultry flock regulations.201222257550
complete genome sequence of bacteriophage ssu5 specific for salmonella enterica serovar typhimurium rough strains.salmonella enterica serovar typhimurium rough strain-specific phage ssu5 was isolated, and its whole genome was sequenced. the 103,229-bp-long double-stranded dna genome of ssu5 encodes 130 open reading frames with one trna for asparagine. genomic analysis revealed that ssu5 might be the phylogenetic origin of cryptic plasmid phcm2 harbored by salmonella typhi ct18.201222966187
regulation of rama by ramr in salmonella enterica serovar typhimurium: isolation of a ramr superrepressor.rama is a transcription factor involved in regulating multidrug resistance in salmonella enterica serovar typhimurium sl1344. green fluorescent protein (gfp) reporter fusions were exploited to investigate the regulation of rama expression by ramr. we show that ramr represses the rama promoter by binding to a palindromic sequence and describe a superrepressor ramr mutant that binds to the rama promoter sequence more efficiently, thus exhibiting a rama inactivated phenotype.201222948865
global transcriptional analysis of dehydrated salmonella enterica serovar typhimurium.despite the scientific and industrial importance of desiccation tolerance in salmonella, knowledge regarding its genetic basis is still scarce. in the present study, we performed a transcriptomic analysis of dehydrated and water-suspended salmonella enterica serovar typhimurium using microarrays. dehydration induced expression of 90 genes and downregulated that of 7 genes. ribosomal structural genes represented the most abundant functional group with a relatively higher transcription during dehy ...201222941081
the late endosomal adaptor p14 is a macrophage host-defense factor against salmonella infection.the outcome of an infection depends on the balance between host resistance and bacterial virulence. here, we show that the late endosomal adaptor p14 (also known as lamtor2) is one of the components for cellular host defense against the intracellular pathogen salmonella enterica serovar typhimurium. during salmonella infection, the complex of p14 and mp1 is required for the accurately timed transport of salmonella through the endolysosomal system. loss of p14 opens a time window that allows salm ...201222427693
evasion of human innate immunity without antagonizing tlr4 by mutant salmonella enterica serovar typhimurium having penta-acylated lipid a.modification of a lipid a moiety in gram-negative bacterial lps to a less acylated form is thought to facilitate bacterial evasion of host innate immunity, thereby enhancing pathogenicity. the contribution of less-acylated lipid a to interactions of whole bacterial cells with host cells (especially in humans) remains unclear. mutant strains of salmonella enterica serovar typhimurium with fewer acylated groups were generated. the major lipid a form in wild-type (wt) and the mutant kcs237 strain i ...201222419537
characterization of dals, an atp-binding cassette transporter for d-alanine, and its role in pathogenesis in salmonella enterica.expansion into new host niches requires bacterial pathogens to adapt to changes in nutrient availability and to evade an arsenal of host defenses. horizontal acquisition of salmonella pathogenicity island (spi)-2 permitted the expansion of salmonella enterica serovar typhimurium into the intracellular environment of host cells by allowing it to deliver bacterial effector proteins across the phagosome membrane. this is facilitated by the ssra-ssrb two-component regulatory system and a type iii se ...201222418438
strand length-dependent antimicrobial activity and membrane-active mechanism of arginine- and valine-rich β-hairpin-like antimicrobial peptides.antimicrobial peptides with amphipathic β-hairpin-like structures have potent antimicrobial properties and low cytotoxicity. the effect of vr or rv motifs on β-hairpin-like antimicrobial peptides has not been investigated. in this study, a series of β-hairpin-like peptides, ac-c(vr)(n)(d)pg (rv)(n)c-nh(2) (n = 1, 2, 3, 4, or 5), were synthesized, and the effect of chain length on antimicrobial activity was evaluated. the antimicrobial activity of the peptides initially increased and then decreas ...201222391533
characterization and differential gene expression between two phenotypic phase variants in salmonella enterica serovar typhimurium.salmonella enterica serovar typhimurium strain 798 has previously been shown to undergo phenotypic phase variation. one of the phenotypes expresses virulence traits such as adhesion, while the other phenotype does not. phenotypic phase variation appears to correlate with the ability of this strain to cause persistent, asymptomatic infections of swine. a new method to detect cells in either phenotypic phase was developed using evans blue-uranine agar plates. using this new assay, rates of phenoty ...201222937065
spontaneous and transient defence against bacteriophage by phase-variable glucosylation of o-antigen in salmonella enterica serovar typhimurium.as natural killers of bacteria, bacteriophages have forced bacteria to develop a variety of defence mechanisms. the alteration of host receptors is one of the most common bacterial defence strategies against phage infection, which completely blocks phage attachment but comes at a potential fitness cost to the bacteria. here, we report the cost-free, transient emergence of phage resistance in salmonella enterica subspecies enterica serovar typhimurium through a phase-variable modification of the ...201222928771
receptor diversity and host interaction of bacteriophages infecting salmonella enterica serovar typhimurium.salmonella enterica subspecies enterica serovar typhimurium is a gram-negative pathogen causing salmonellosis. salmonella typhimurium-targeting bacteriophages have been proposed as an alternative biocontrol agent to antibiotics. to further understand infection and interaction mechanisms between the host strains and the bacteriophages, the receptor diversity of these phages needs to be elucidated.201222927964
type i interferon induces necroptosis in macrophages during infection with salmonella enterica serovar typhimurium.salmonella enterica serovar typhimurium (s. typhimurium) is a virulent pathogen that induces rapid host death. here we observed that host survival after infection with s. typhimurium was enhanced in the absence of type i interferon signaling, with improved survival of mice deficient in the receptor for type i interferons (ifnar1(-/-) mice) that was attributed to macrophages. although there was no impairment in cytokine expression or inflammasome activation in ifnar1(-/-) macrophages, they were h ...201222922364
cationic antimicrobial peptides serve as activation signals for the salmonella typhimurium phopq and pmrab regulons in vitro and in vivo.salmonella enterica serovar typhimurium uses two-component regulatory systems (tcrss) to respond to environmental stimuli. upon infection, the tcrss phop-phoq (phopq) and pmra-pmrb (pmrab) are activated by environmental signals detected in the lumen of the intestine and within host cells. tcrs-mediated gene expression leads to upregulation of genes involved in lipopolysaccharide (lps) modification and cationic antimicrobial peptide (camp) resistance. this research expands on previous studies whi ...201222919691
caspase-11 increases susceptibility to salmonella infection in the absence of caspase-1.inflammasomes are cytosolic multiprotein complexes assembled by intracellular nucleotide-binding oligomerization domain (nod)-like receptors (nlrs) and they initiate innate immune responses to invading pathogens and danger signals by activating caspase-1 (ref. 1). caspase-1 activation leads to the maturation and release of the pro-inflammatory cytokines interleukin (il)-1β and il-18, as well as lytic inflammatory cell death known as pyroptosis. recently, a new non-canonical inflammasome was desc ...201222895188
biofilm formation, cell surface hydrophobicity, and fatty acids analysis of starved salmonella enterica serovar typhimurium in seawater.salmonella is an international foodborne pathogen widely disseminated in seawater that regularly causes large outbreaks of food poisoning. in this study, we have investigated the effect of starvation on the ability of salmonella enterica serovar typhimurium cells to adhere to polystyrene microplate and hep2 cells in seawater microcosms after incubation for 3 years. cell surface hydrophobicity was evaluated. effect of stress on fatty acids composition was also established. our results showed that ...201222891961
non-genetic diversity shapes infectious capacity and host resistance.the spontaneous generation of distinct phenotypes within a clonal population of cells allows for both bet-hedging at the population level and the division of labor among subpopulations. this is emerging as an important theme in bacterial pathogenesis, because bacterial pathogens exhibit phenotypic heterogeneity with respect to characteristics that impact virulence. the phenomenon of persister cells and models of salmonella enterica serovar typhimurium (s. typhimurium) pathogenesis illustrate the ...201222889945
low-shear modeled microgravity enhances salmonella enterica resistance to hydrogen peroxide through a mechanism involving katg and katn.studies carried out in recent years have established that growth under conditions of reduced gravity enhances salmonella enterica serovar typhimurium virulence. to analyze the possibility that this microgravity-induced increase in pathogenicity could involve alterations in the ability of salmonella to withstand oxidative stress, we have compared the resistance to hydrogen peroxide of various salmonella enterica strains grown under conditions of low shear modeled microgravity (lsmmg) or normal gr ...201222888375
evolution of a multiple antibiotic resistance region in inchi1 plasmids: reshaping resistance regions in situ.to determine the structure of the resistance region in an inchi1 plasmid conferring resistance to multiple antibiotics, including gentamicin, recovered from a salmonella enterica serovar typhimurium isolate from a horse.201222888274
myd88 signaling promotes both mucosal homeostatic and fibrotic responses during salmonella-induced colitis.salmonella enterica serovar typhimurium is a clinically important gram-negative, enteric bacterial pathogen that activates several toll-like receptors (tlrs). while tlr signaling through the adaptor protein myd88 has been shown to promote inflammation and host defense against the systemic spread of s. typhimurium, curiously, its role in the host response against s. typhimurium within the mammalian gastrointestinal (gi) tract is less clear. we therefore used the recently described salmonella-indu ...201222679002
selective purification of recombinant neuroactive peptides using the flagellar type iii secretion system.the structure, assembly, and function of the bacterial flagellum involves about 60 different proteins, many of which are selectively secreted via a specific type iii secretion system (t3ss) (j. frye et al., j. bacteriol. 188:2233-2243, 2006). the t3ss is reported to secrete proteins at rates of up to 10,000 amino acid residues per second. in this work, we showed that the flagellar t3ss of salmonella enterica serovar typhimurium could be manipulated to export recombinant nonflagellar proteins thr ...201222647788
effect of salmonella enteric serovar typhimurium in pregnant mice: a biochemical and histopathological study.food borne infections caused by salmonella enterica species are increasing globally and pregnancy poses a significant threat in developing countries, where sanitation facilities are inadequate. thus, the present study was designed to delineate the effect of salmonella infection during pregnancy.201227785189
role of mouse peptidoglycan recognition protein pglyrp2 in the innate immune response to salmonella enterica serovar typhimurium infection in vivo.peptidoglycan recognition proteins (pgrps) are a family of innate pattern recognition molecules that bind bacterial peptidoglycan. while the role of pgrps in drosophila innate immunity has been extensively studied, how the four mammalian pgrp proteins (pglyrp1 to pglyrp4) contribute to host defense against bacterial pathogens in vivo remains poorly understood. pglyrp1, pglyrp3, and pglyrp4 are directly bactericidal in vitro, whereas pglyrp2 is an n-acetylmuramyl-l-alanine amidase that cleaves pe ...201222615249
the evaluation of a pcr-based method for identification of salmonella enterica serotypes from environmental samples and various food matrices.the most commonly used method for serotyping salmonella spp. is based on the kaufmann-white scheme, and is composed of serological reactions using antibodies to lps agglutinins. the multiplex pcr used in this investigation was established by kim et al. to serotype the 30 most common clinical salmonella serotypes, as determined by cdc. the pcr assay consists of two five-plex reactions and a single two-plex pcr reaction, based on six genetic loci from salmonella enterica serotype typhimurium and f ...201222608224
stm2209-stm2208 (opvab): a phase variation locus of salmonella enterica involved in control of o-antigen chain length.stm2209 and stm2208 are contiguous loci annotated as putative protein-coding genes in the chromosome of salmonella enterica. lack of homologs in related enterobacteria and low g+c content suggest that s. enterica may have acquired stm2209-stm2208 by horizontal transfer. stm2209 and stm2208 are co-transcribed from a promoter upstream stm2209, and their products are inner (cytoplasmic) membrane proteins. analysis with the bacterial adenylate cyclase two-hybrid system suggests that stm2209 and stm2 ...201222606300
dietary rice bran promotes resistance to salmonella enterica serovar typhimurium colonization in mice.dietary rice bran consists of many bioactive components with disease fighting properties; including the capacity to modulate the gut microbiota. studies point to the important roles of the gut microbiota and the mucosal epithelium in the establishment of protection against enteric pathogens, such as salmonella. the ability of rice bran to reduce the susceptibility of mice to a salmonella infection has not been previously investigated. therefore, we hypothesized that the incorporation of rice bra ...201222583915
salmonella biofilm development depends on the phosphorylation status of rcsb.the rcs phosphorelay pathway is a complex signaling pathway involved in the regulation of many cell surface structures in enteric bacteria. in response to environmental stimuli, the sensor histidine kinase (rcsc) autophosphorylates and then transfers the phosphate through intermediary steps to the response regulator (rcsb), which, once phosphorylated, regulates gene expression. here, we show that salmonella biofilm development depends on the phosphorylation status of rcsb. thus, unphosphorylated ...201222582278
comparative proteomic analysis of salmonella tolerance to the biocide active agent triclosan.concern has been expressed about the overuse of biocides in farm animal production and food industries. biocide application can create selective pressures that lead to increased tolerance to one or more of these compounds and are concomitant with the emergence of cross-resistance to antibiotics. a triclosan sensitive salmonella enterica serovar typhimurium and the isogenic triclosan tolerant mutant were studied at the proteomic level in order to elucidate cellular mechanisms that facilitate bioc ...201222579747
effect of farm type on within-herd salmonella prevalence, serovar distribution, and antimicrobial resistance.salmonella represents a major challenge to the pig industry, as pork presents a risk for human salmonellosis. in this study, we have examined the effect of farm type on the prevalence of fattening pigs shedding salmonella on 12 farms at risk for harboring salmonella. on six open (grow-to-finish) and six closed (farrow-to-finish) farms, the prevalence of pigs shedding salmonella was determined on two occasions approximately 2 months apart. the serovar, phage type, and antimicrobial resistance of ...201222564934
targeted therapy via oral administration of attenuated salmonella expression plasmid-vectored stat3-shrna cures orthotopically transplanted mouse hcc.the development of rna interference-based cancer gene therapies has been delayed due to the lack of effective tumor-targeting delivery systems. attenuated salmonella enterica serovar typhimurium (s. typhimurium) has a natural tropism for solid tumors. we report here the use of attenuated s. typhimurium as a vector to deliver shrna directly into tumor cells. constitutively activated signal transducer and activator of transcription 3 (stat3) is a key transcription factor involved in both hepatocel ...201222555509
srnas and the virulence of salmonella enterica serovar typhimurium.the combination of genomics and high-throughput cdna sequencing technologies has facilitated the identification of many small rnas (srnas) that play a central role in the post-transcriptional gene regulation of salmonella enterica serovar typhimurium. to date, most of the functionally characterized srnas have been involved in the regulation of processes which are not directly linked to virulence. just five srnas have been found to affect the ability of salmonella to replicate within mammalian ce ...201222546935
hypochlorous acid and hydrogen peroxide-induced negative regulation of salmonella enterica serovar typhimurium ompw by the response regulator arca.hydrogen peroxide (h2o2) and hypochlorous acid (hocl) are reactive oxygen species that are part of the oxidative burst encountered by salmonella enterica serovar typhimurium (s. typhimurium) upon internalization by phagocytic cells. in order to survive, bacteria must sense these signals and modulate gene expression. growing evidence indicates that the arcab two component system plays a role in the resistance to reactive oxygen species. we investigated the influx of h2o2 and hocl through ompw and ...201222545862
evidence for lack of acquisition of tolerance in salmonella enterica serovar typhimurium atcc 14028 after exposure to subinhibitory amounts of origanum vulgare l. essential oil and carvacrol.overnight exposure of salmonella enterica serovar typhimurium to sublethal amounts of origanum vulgare essential oil (ov) and carvacrol (car) did not result in direct and cross-bacterial protection. cells subcultured with increasing amounts of ov or car survived up to the mic of either compound, revealing few significant changes in bacterial susceptibility.201222544235
the transcriptional landscape and small rnas of salmonella enterica serovar typhimurium.more than 50 y of research have provided great insight into the physiology, metabolism, and molecular biology of salmonella enterica serovar typhimurium (s. typhimurium), but important gaps in our knowledge remain. it is clear that a precise choreography of gene expression is required for salmonella infection, but basic genetic information such as the global locations of transcription start sites (tsss) has been lacking. we combined three rna-sequencing techniques and two sequencing platforms to ...201222538806
quantifying ligand binding to large protein complexes using electrospray ionization mass spectrometry.an electrospray ionization mass spectrometry (esi-ms) method for quantifying protein-ligand complexes that cannot be directly detected by esi-ms is described. the proxy protein esi-ms method combines direct esi-ms binding measurements with competitive protein-ligand binding. to implement the method, a proxy protein (p(proxy)), which interacts specifically with the ligand of interest with known affinity and can be detected directly by esi-ms, is used to quantitatively monitor the extent of ligand ...201222507285
three-axis model for atg recruitment in autophagy against salmonella.salmonella enterica serovar typhimurium enter epithelial cells and take up residence there. within epithelial cells, a portion of the bacteria are surrounded by an autophagosome-like double-membrane structure, and they are still residing within the salmonella-containing vacuole (scv). in this paper, we will discuss how the autophagy machinery is recruited in proximity to salmonella. the formation of this double membrane requires atg9l1 and fip200; these proteins are important for autophagy-speci ...201222505927
analysis of hilc/d-dependent invf promoter expression under different culture conditions.in salmonella enterica serovar typhimurium, many of the genes required for intestinal penetration and invasion of host cells are encoded within the salmonella pathogenicity island 1 (spi1). the expression of invf, which is a positive transcriptional activator of spi1, is controlled by hila-dependent (invf-1) and hilc/d-dependent (invf-2) promoters. transcriptional analysis of invf revealed that the invf-2 promoter (p(invf-2)) was not activated when cells were grown in standing culture conditions ...201222480973
association of a protective monoclonal iga with the o antigen of salmonella enterica serovar typhimurium impacts type 3 secretion and outer membrane integrity.invasion of intestinal epithelial cells by salmonella enterica serovar typhimurium is an energetically demanding process, involving the transfer of effector proteins from invading bacteria into host cells via a specialized organelle known as the salmonella pathogenicity island 1 (spi-1) type 3 secretion system (t3ss). by a mechanism that remains poorly understood, entry of s. typhimurium into epithelial cells is inhibited by sal4, a monoclonal, polymeric iga antibody that binds an immunodominant ...201222473607
improving resolution of public health surveillance for human salmonella enterica serovar typhimurium infection: 3 years of prospective multiple-locus variable-number tandem-repeat analysis (mlva).prospective typing of salmonella enterica serovar typhimurium (stm) by multiple-locus variable-number tandem-repeat analysis (mlva) can assist in identifying clusters of stm cases that might otherwise have gone unrecognised, as well as sources of sporadic and outbreak cases. this paper describes the dynamics of human stm infection in a prospective study of stm mlva typing for public health surveillance.201222462487
presence and persistence of salmonella enterica serotype typhimurium in the phyllosphere and rhizosphere of spray-irrigated parsley.salmonella enterica is one of the major food-borne pathogens associated with ready-to-eat fresh foods. although polluted water might be a significant source of contamination in the field, factors that influence the transfer of salmonella from water to the crops are not well understood, especially under conditions of low pathogen levels in water. the aim of this study was to investigate the short- and long-term (1 h to 28 days) persistence of salmonella enterica serotype typhimurium in the phyllo ...201222447598
enhancement of the anti-salmonella immune response in cd154-deficient mice by an attenuated, ifn-γ-expressing, strain of salmonella enterica serovar typhimurium.previously, we demonstrated that cell-cell communications via the cd40-cd154 pathway play a critical role in the induction of type 1 cytokine responses, including il-12 and ifn-γ, which in turn greatly influence the response to salmonella infections. mice genetically deficient in the expression of cd154 exhibited markedly increased susceptibility to infection by an attenuated, double auxotrophic (aroa-arod-) strain, designated brd509, of salmonella enterica serovar typhimurium. in the present st ...201222445817
an altered immune response, but not individual cationic antimicrobial peptides, is associated with the oral attenuation of ara4n-deficient salmonella enterica serovar typhimurium in mice.salmonella enterica serovar typhimurium (s. typhimurium) uses two-component regulatory systems (tcrs) to respond to stimuli in the local microenvironment. upon infection, the salmonella tcrss phop-phoq (phopq) and pmra-pmrb (pmrab) are activated by environmental signals in the intestinal lumen and within host cells. tcrs-mediated gene expression results in lipopolysaccharide (lps) modification and cationic antimicrobial peptide resistance. the pmra-regulated pmrhfijklm operon mediates 4-amino-4- ...201223166721
phosphorylation of nlrc4 is critical for inflammasome activation.nlrc4 is a cytosolic member of the nod-like receptor family that is expressed in innate immune cells. it senses indirectly bacterial flagellin and type iii secretion systems, and responds by assembling an inflammasome complex that promotes caspase-1 activation and pyroptosis. here we use knock-in mice expressing nlrc4 with a carboxy-terminal 3×flag tag to identify phosphorylation of nlrc4 on a single, evolutionarily conserved residue, ser 533, following infection of macrophages with salmonella e ...201222885697
grapefruit juice and its constituents augment the effect of low ph on inhibition of survival and adherence to intestinal epithelial cells of salmonella enterica serovar typhimurium pt193.the present study examined the survival of salmonella typhimurium and its adherence to intestinal epithelial cells following inoculation into grapefruit juice and apple cider. both liquids significantly inactivated s. typhimurium (0.8-2.2 log reduction compared to the control); surviving salmonella in grapefruit juice was 1.0-1.4 log lower than in apple cider at 24h incubation. grapefruit juice contains the antimicrobial substances naringin (nar) and naringenin (nge); however, the effect of grap ...201222867848
tandem attenuators control expression of the salmonella mgtcbr virulence operon.the mgtcbr operon from salmonella enterica serovar typhimurium specifies the virulence protein mgtc, the mg(2+) transporter mgtb and the regulatory peptide mgtr. the mgtcbr transcript includes a long leader region harbouring two short open reading frames (orfs). translation of these orfs is anticipated to impact the formation of particular stem-loop structures and control transcription of the coding region by an attenuation-like mechanism. we previously reported that orf mgtm enables salmonella ...201222857388
promoter strength driving tetr determines the regulatory properties of tet-controlled expression systems.bacteria frequently rely on transcription repressors and activators to alter gene expression patterns in response to changes in the surrounding environment. tet repressor (tetr) is a paradigm transcription factor that senses the environmental state by binding small molecule effectors, the tetracyclines. however, recently isolated peptides that act as inducers of tetr after having been fused to the c-terminus of a carrier protein, suggest that tetr can also regulate gene expression in a signal-tr ...201222848546
zinc prevents salmonella enterica serovar typhimurium-induced loss of intestinal mucosal barrier function in broiler chickens.the study was carried out to evaluate the beneficial effects of supplemental zinc (zn) on the intestinal mucosal barrier function in salmonella enterica serovar typhimurium-challenged broiler chickens in a 42-day experiment. a total of 336 1-day-old male arbor acres broiler chicks were assigned to eight treatment groups. a 4×2 factorial arrangement of treatments was used in a completely randomized experimental design to study the effects of levels of supplemental zn (0, 40, 80 and 120 mg/kg diet ...201222834550
spi-1 encoded genes of salmonella typhimurium influence differential polarization of porcine alveolar macrophages in vitro.within the last decade, macrophages have been shown to be capable of differentiating toward a classically activated phenotype (m1) with a high antimicrobial potential or an alternatively activated phenotype (m2). some pathogens are capable of interfering with differentiation in order to down-regulate the anti-microbial activity and enhance their survival in the host.201222817641
comparative genome analysis of the high pathogenicity salmonella typhimurium strain uk-1.salmonella enterica serovar typhimurium, a gram-negative facultative rod-shaped bacterium causing salmonellosis and foodborne disease, is one of the most common isolated salmonella serovars in both developed and developing nations. several s. typhimurium genomes have been completed and many more genome-sequencing projects are underway. comparative genome analysis of the multiple strains leads to a better understanding of the evolution of s. typhimurium and its pathogenesis. s. typhimurium strain ...201222792393
diarrhea and colitis in mice require the salmonella pathogenicity island 2-encoded secretion function but not sifa or spv effectors.we investigated the roles of salmonella pathogenicity island 2 (spi-2) and two spi-2 effectors in salmonella colitis and diarrhea in genetically resistant balb/c.d2(slc11a1) congenic mice with the wild-type nramp1 locus. wild-type salmonella enterica serovar typhimurium 14028s caused a pan-colitis, and the infected mice developed frank diarrhea with a doubling of the fecal water content. an ssav mutant caused only a 26% increase in fecal water content, without producing the pathological changes ...201222778101
a whole-cell phenotypic screening platform for identifying methylerythritol phosphate pathway-selective inhibitors as novel antibacterial agents.isoprenoid biosynthesis is essential for survival of all living organisms. more than 50,000 unique isoprenoids occur naturally, with each constructed from two simple five-carbon precursors: isopentenyl diphosphate (ipp) and dimethylallyl diphosphate (dmapp). two pathways for the biosynthesis of ipp and dmapp are found in nature. humans exclusively use the mevalonate (mva) pathway, while most bacteria, including all gram-negative and many gram-positive species, use the unrelated methylerythritol ...201222777049
a salmonella typhimurium-translocated glycerophospholipid:cholesterol acyltransferase promotes virulence by binding to the rhoa protein switch regions.salmonella enterica serovar typhimurium translocates a glycerophospholipid:cholesterol acyltransferase (ssej) into the host cytosol after its entry into mammalian cells. ssej is recruited to the cytoplasmic face of the host cell phagosome membrane where it is activated upon binding the small gtpase, rhoa. ssej is regulated similarly to cognate eukaryotic effectors, as only the gtp-bound form of rhoa family members stimulates enzymatic activity. using nmr and biochemistry, this work demonstrates ...201222740689
loss of or inhibition of all multidrug resistance efflux pumps of salmonella enterica serovar typhimurium results in impaired ability to form a biofilm.to investigate the contribution of multidrug efflux pump systems of salmonella enterica serovar typhimurium to the formation of a competent biofilm.201222733653
the bimodal lifestyle of intracellular salmonella in epithelial cells: replication in the cytosol obscures defects in vacuolar replication.salmonella enterica serovar typhimurium invades and proliferates within epithelial cells. intracellular bacteria replicate within a membrane bound vacuole known as the salmonella containing vacuole. however, this bacterium can also replicate efficiently in the cytosol of epithelial cells and net intracellular growth is a product of both vacuolar and cytosolic replication. here we have used semi-quantitative single-cell analyses to investigate the contribution of each of these replicative niches ...201222719929
human milk mucin 1 and mucin 4 inhibit salmonella enterica serovar typhimurium invasion of human intestinal epithelial cells in vitro.many human milk glycans inhibit pathogen binding to host receptors and their consumption by infants is associated with reduced risk of disease. salmonella infection is more frequent among infants than among the general population, but the incidence is lower in breast-fed babies, suggesting that human milk could contain components that inhibit salmonella. this study aimed to test whether human milk per se inhibits salmonella invasion of human intestinal epithelial cells in vitro and, if so, to id ...201222718031
a previously uncharacterized gene stm0551 plays a repressive role in the regulation of type 1 fimbriae in salmonella enterica serotype typhimurium.salmonella enterica serotype typhimurium produces surface-associated fimbriae that facilitate adherence of the bacteria to a variety of cells and tissues. type 1 fimbriae with binding specificity to mannose residues are the most commonly found fimbrial type. in vitro, static-broth culture favors the growth of s. typhimurium with type 1 fimbriae, whereas non-type 1 fimbriate bacteria are obtained by culture on solid-agar media. previous studies demonstrated that the phenotypic expression of type ...201222716649
the importance of motility and chemotaxis for extra-animal survival of salmonella enterica serovar typhimurium and dublin.this study investigated the importance of flagella and motility of salmonella enterica serovar typhimurium and dublin in models of extra-animal survival.201222716502
analyzing cellular internalization of nanoparticles and bacteria by multi-spectral imaging flow cytometry.nanoparticulate systems have emerged as valuable tools in vaccine delivery through their ability to efficiently deliver cargo, including proteins, to antigen presenting cells. internalization of nanoparticles (np) by antigen presenting cells is a critical step in generating an effective immune response to the encapsulated antigen. to determine how changes in nanoparticle formulation impact function, we sought to develop a high throughput, quantitative experimental protocol that was compatible wi ...201222710268
expression and delivery of tetanus toxin fragment c fused to the n-terminal domain of sipb enhances specific immune responses in mice.live attenuated bacteria can be used as a carrier for the delivery of foreign antigens to a host's immune system. the n-terminal domain of sipb, a translocon protein of the type iii secretion system of salmonella enterica serovar typhimurium, is required for secretion and outer membrane localization. in the present study, vaccine plasmids for antigen delivery in which the non-toxic tetanus toxin fragment c (ttfc), which contains a t cell epitope, is fused to the n-terminal 160 amino acids of sip ...201222708880
slc11a1 (nramp1) impairs growth of salmonella enterica serovar typhimurium in macrophages via stimulation of lipocalin-2 expression.the expression of the cation transporter nramp1 (slc11a1) in late phagolysosomes confers resistance to infection with several intracellular pathogens, such as salmonella enterica, in mice. the antimicrobial actions of nramp1 are attributable, in part, to modulation of macrophage immune function and cellular iron metabolism--the latter affecting the availability of the essential nutrient iron for intraphagosomal bacteria. here, we provide novel evidence that nramp1 functionality increases the exp ...201222706314
mechanisms used by virulent salmonella to impair dendritic cell function and evade adaptive immunity.innate and adaptive immunity are inter-related by dendritic cells (dcs), which directly recognize bacteria through the binding of pathogen-associated molecular patterns (pamps) to specialized receptors on their surface. after capturing and degrading bacteria, dcs present their antigens as small peptides bound to mhc molecules and prime naive bacteria-specific t cells. in response to pamp recognition dcs undergo maturation, which is a phenotypic change that increases their immunogenicity and prom ...201222703384
effect of iacp mutation on flagellar phase variation in salmonella enterica serovar typhimurium strain uk-1.flagella are surface appendages that are important for bacterial motility and invasion of host cells. two flagellin subunits in salmonella enterica serovar typhimurium, flic and fljb, are alternatively expressed by a site-specific dna inversion mechanism called flagellar phase variation. although this inversion mechanism is understood at the molecular level, the key factor controlling the expression of the two flagellin subunits has not been determined. in this study, we found that a putative ac ...201222685287
cysteine catabolism and cysteine desulfhydrase (cdsh/stm0458) in salmonella enterica serovar typhimurium.cysteine is potentially toxic and can affect diverse functions such as oxidative stress, antibiotic resistance, and swarming motility. the contribution of cysteine catabolism in modulating responses to cysteine has not been examined, in part because the genes have not been identified and mutants lacking these genes have not been isolated or characterized. we identified the gene for a previously described cysteine desulfhydrase, which we designated cdsh (formerly stm0458). we also identified a di ...201222685283
flagella overexpression attenuates salmonella pathogenesis.flagella are cell surface appendages involved in a number of bacterial behaviors, such as motility, biofilm formation, and chemotaxis. despite these important functions, flagella can pose a liability to a bacterium when serving as potent immunogens resulting in the stimulation of the innate and adaptive immune systems. previous work showing appendage overexpression, referred to as attenuating gene expression (age), was found to enfeeble wild-type salmonella. thus, this approach was adapted to di ...201223056473
genetic manipulation of pathogenicity loci in non-typhimurium salmonella.the traditional genetic tools used in salmonella enterica serovar typhimurium rely heavily on a high-transducing mutant of bacteriophage p22. p22 recognizes its hosts by the structure of their o-antigens, which vary among serovars of salmonella; therefore, it cannot be used in most non-typhimurium salmonella, including the majority of those causing food-borne illnesses in both humans and livestock. bacteriophage p1 infects a variety of enteric bacteria, including gale mutants of serovar typhimur ...201223041268
on-cell mas nmr: physiological clues from living cells.while structural information on biomolecules is mainly obtained from purified in vitro samples, nmr can also be applied in the context of entire cells or organisms. the present study describes maturation processes in living salmonella enterica serovar typhimurium, a prevalent cause for human gastroenteritis. in our physiological study, we follow the composition of the o-antigen on the outer bacterial membrane with high-resolution mas nmr spectroscopy. we detect and characterize an evolution of t ...201223030432
very long o-antigen chains enhance fitness during salmonella-induced colitis by increasing bile resistance.intestinal inflammation changes the luminal habitat for microbes through mechanisms that have not been fully resolved. we noticed that the fepe regulator of very long o-antigen chain assembly in the enteric pathogen salmonella enterica serotype typhimurium (s. typhimurium) conferred a luminal fitness advantage in the mouse colitis model. however, a fepe mutant was not defective for survival in tissue, resistance to complement or resistance to polymyxin b. we performed metabolite profiling to ide ...201223028318
microbial amyloids induce interleukin 17a (il-17a) and il-22 responses via toll-like receptor 2 activation in the intestinal mucosa.the toll-like receptor 2 (tlr2)/tlr1 receptor complex responds to amyloid fibrils, a common component of biofilm material produced by members of the phyla firmicutes, bacteroidetes, and proteobacteria. to determine whether this tlr2/tlr1 ligand stimulates inflammatory responses when bacteria enter intestinal tissue, we investigated whether expression of curli amyloid fibrils by the invasive enteric pathogen salmonella enterica serotype typhimurium contributes to t helper 1 and t helper 17 respon ...201223027540
the pmrab system-inducing conditions control both lipid a remodeling and o-antigen length distribution, influencing the salmonella typhimurium-host interactions.the salmonella enterica serovar typhimurium lipopolysaccharide consisting of covalently linked lipid a, non-repeating core oligosaccharide, and the o-antigen polysaccharide is the most exposed component of the cell envelope. previous studies demonstrated that all of these regions act against the host immunity barrier. the aim of this study was to define the role and interaction of pmrab-dependent gene products required for the lipopolysaccharide component synthesis or modification mainly during ...201223019341
expression of stm4467-encoded arginine deiminase controlled by the stm4463 regulator contributes to salmonella enterica serovar typhimurium virulence.arginine deiminase (adi), carbamate kinase (ck), and ornithine transcarbamoylase (otc) constitute the adi system. in addition to metabolic functions, the adi system has been implicated in the virulence of certain pathogens. the pathogenic intracellular bacterium salmonella enterica serovar typhimurium possesses the stm4467, stm4466, and stm4465 genes, which are predicted to encode adi, ck, and otc, respectively. here we report that the stm4467 gene encodes an adi and that adi activity plays a ro ...201223006851
targeting essential genes in salmonella enterica serovar typhimurium with antisense peptide nucleic acid.we investigated the capability of antisense peptide nucleic acids (pnas) conjugated to the (kff)(3)k cell-penetrating peptide to target possible essential genes (liga, rpoa, rpod, enga, tsf, and kdta) in salmonella enterica serovar typhimurium and inhibit bacterial growth in vitro and in cell culture. all targeted pna-based gene inhibition has shown great potency in gene expression inhibition in a sequence-specific and dose-dependent manner at micromolar concentrations. among tested pnas, the an ...201223006748
prevalence of salmonella enterica serovar 4,[5],12:i:- in england and wales, 2010.difficulties in accurately identifying serovar 4,[5],12:i:- as monophasic variants of salmonella enterica serovar typhimurium mean there is confusion in the reporting of serovars typhimurium and 4,[5],12:i:-. to gain insight into the prevalence and diversity of these monophasic variants in england and wales, screening for fljb, hin and the serovar 4,[5],12:i:- dt193-associated genomic island was conducted on 609 s. enterica isolates designated as definitive phage type (dt) 193, and 142 isolates ...201222995432
persistence of salmonella enterica during dehydration and subsequent cold storage.despite the fact that salmonella enterica serotype typhimurium sl 1344 has served as a model pathogen in many studies, information regarding its desiccation response is still scarce. in this study, we investigated environmental conditions that affect salmonella survival following dehydration and subsequent cold storage, using a 96-well polystyrene plate model. the sl 1344 strain exhibited high survival compared with other typhimurium isolates and s. enterica serotypes. further characterization o ...201222986208
membrane topology of salmonella invasion protein sipb confers osmotolerance.salmonella enterica serovar typhimurium is a major cause of human gastrointestinal illness worldwide. this pathogen can persist in a wide range of environments, making it of great concern to public health. here, we report that the salmonella pathogenicity island (spi)-1 effector protein sipb exhibits a membrane topology that confers bacterial osmotolerance. disruption of the sipb gene or the invg gene (spi-1 component) significantly reduced the osmotolerance of s. typhimurium lt2. biochemical as ...201222975346
m cell differentiation: distinct lineage or phenotypic transition? salmonella provides answers.whether m cells arise from a distinct lineage or result from phenotypic transition is a matter of debate. in this issue of cell host & microbe, tahoun et al. (2012) provide evidence that sopb, a virulence factor of salmonella enterica serovar typhimurium, can induce phenotypic transition of lymphoid follicle-associated enterocytes into m cells.201223159049
neutrophil elastase alters the murine gut microbiota resulting in enhanced salmonella colonization.the intestinal microbiota has been found to play a central role in the colonization of salmonella enterica serovar typhimurium in the gastrointestinal tract. in this study, we present a novel process through which salmonella benefit from inflammatory induced changes in the microbiota in order to facilitate disease. we show that salmonella infection in mice causes recruitment of neutrophils to the gut lumen, resulting in significant changes in the composition of the intestinal microbiota. this oc ...201223155475
systemic flagellin immunization stimulates mucosal cd103+ dendritic cells and drives foxp3+ regulatory t cell and iga responses in the mesenteric lymph node.mucosal immunity is poorly activated after systemic immunization with protein ags. nevertheless, induction of mucosal immunity in such a manner would be an attractive and simple way to overcome the intrinsic difficulties in delivering ag to such sites. flagellin from salmonella enterica serovar typhimurium (flic) can impact markedly on host immunity, in part via its recognition by tlr5. in this study, we show that systemic immunization with soluble flic (sflic) drives distinct immune responses c ...201223152564
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