Publications

TitleAbstractYear(sorted descending)
Filter
PMID
Filter
immunometabolic phenotype alterations associated with the induction of disease tolerance and persistent asymptomatic infection of salmonella in the chicken intestine.the adaptation of salmonella enterica to the eukaryotic host is a key process that enables the bacterium to survive in a hostile environment. salmonella have evolved an intimate relationship with its host that extends to their cellular and molecular levels. colonization, invasion, and replication of the bacteria in an appropriate host suggest that modification of host functions is central to pathogenesis. intuitively, this subversion of the cell must be a complex process, since hosts are not inh ...201728421074
regional transmission of salmonella paratyphi a, china, 1998-2012.to explore transmission patterns and genetic relationships of salmonella enterica serovar paratyphi a in china, we conducted a genome-wide single-nucleotide polymorphism analysis on the strains in the 4 provinces in which incidence was highest during 1998-2012. markedly phylogeographic clustering suggested regional virus circulation after introduction from areas in southeastern china.201728418315
dissemination of mcr-1-carrying plasmids among colistin-resistant salmonella strains from humans and food-producing animals in taiwan.we detected the colistin resistance gene mcr-1 in four salmonella serovars isolated from humans and animals with diarrhea. the resistance gene was carried on different plasmids. one mcr-1-carrying conjugative plasmid, a variant of phnshp45, was disseminated among salmonella isolates recovered from humans, pigs, and chickens.201728416545
reversible synthesis of colanic acid and o-antigen polysaccharides in salmonella typhimurium enhances induction of cross-immune responses and provides protection against heterologous salmonella challenge.colanic acid (ca) and lipopolysaccharide (lps) are two major mannose-containing extracellular polysaccharides of salmonella. their presence on the bacterial surface can mask conserved protective outer membrane proteins (omps) from the host immune system. the mannose moiety in these molecules is derived from gdp-mannose, which is synthesized in several steps. the first two steps require the action of phosphomannose isomerase, encoded by pmi (mana), followed by phosphomannomutase, encoded by manb. ...201728412074
modified bacteriophage s16 long tail fiber proteins for rapid and specific immobilization and detection of salmonella cells.bacteriophage-based assays and biosensors rival traditional antibody-based immunoassays for detection of low-level salmonella contaminations. in this study, we harnessed the binding specificity of the long tail fiber (ltf) from bacteriophage s16 as an affinity molecule for the immobilization, enrichment, and detection of salmonella we demonstrate that paramagnetic beads (mbs) coated with recombinant gp37-gp38 ltf complexes (ltf-mbs) are highly effective tools for rapid affinity magnetic separati ...201728411223
salmonella typhimurium diarrhea reveals basic principles of enteropathogen infection and disease-promoted dna exchange.despite decades of research, efficient therapies for most enteropathogenic bacteria are still lacking. in this review, we focus on salmonella enterica typhimurium (s. typhimurium), a frequent cause of acute, self-limiting food-borne diarrhea and a model that has revealed key principles of enteropathogen infection. we review the steps of gut infection and the mucosal innate-immune defenses limiting pathogen burdens, and we discuss how inflammation boosts gut luminal s. typhimurium growth. we also ...201728407482
mucosal iga and ifn-γ(+) cd8 t cell immunity are important in the efficacy of live salmonella enteria serovar choleraesuis vaccines.salmonellosis, a disease caused by non-typhoidal salmonella strains which can be transmitted from swine to humans, is one of the leading public health problems around the world. paratyphoid of swine is controlled by vaccinating swine with salmonella enterica serovar choleraesuis (s. choleraesuis) live vaccine strain c500 in china. although the vaccine has good prophylactic efficacy, the mechanism of immunogenicity is unclear. using a c500-derived paratyphoid thermo-stable live vaccine (ptsl vacc ...201728406162
high-avidity iga protects the intestine by enchaining growing bacteria.vaccine-induced high-avidity iga can protect against bacterial enteropathogens by directly neutralizing virulence factors or by poorly defined mechanisms that physically impede bacterial interactions with the gut tissues ('immune exclusion'). iga-mediated cross-linking clumps bacteria in the gut lumen and is critical for protection against infection by non-typhoidal salmonella enterica subspecies enterica serovar typhimurium (s. typhimurium). however, classical agglutination, which was thought t ...201728405025
antimicrobial resistance of salmonella enterica serovar typhimurium in shanghai, china.we aimed to analyze the antimicrobial resistance phenotypes and to elucidate the molecular mechanisms underlying resistance to cephalosporins, ciprofloxacin, and azithromycin in salmonella enterica serovar typhimurium isolates identified from patients with diarrhea in shanghai. the isolates showed high rates of resistance to traditional antimicrobials, and 20.6, 12.7, and 5.5% of them exhibited decreased susceptibility to cephalosporins, ciprofloxacin, and azithromycin, respectively. notably, 47 ...201728400764
molecular characterization and antimicrobial resistance of salmonella enterica from swine slaughtered in two different types of philippine abattoir.salmonella enterica is a well-known pathogen commonly acquired from the consumption of contaminated food. it has been estimated to affect millions of humans and cause hundreds of thousands of deaths per year globally. pork, one of the most commonly consumed meats worldwide, has been identified as one of the main sources of human salmonellosis. in this study, we aimed to detect and characterize s. enterica from slaughtered swine and generate antimicrobial resistance profiles of select isolates. t ...201728400019
oregano essential oil-based natural antimicrobial packaging film to inactivate salmonella enterica and yeasts/molds in the atmosphere surrounding cherry tomatoes.this study investigated the effectiveness of a polyvinyl alcohol (pva) film containing the natural antimicrobial oregano essential oil (oeo) as an active packaging application for decreasing the microbial growth. the film exerted an antimicrobial effect via the atmosphere surrounding the food rather than direct contact, thereby preserving the quality of cherry tomatoes. a packaging film containing microencapsulated oeo was developed. the loading content increased gradually (104.29-234.29 μg oeo/ ...201728399993
purification and characterization of the bacterial flagellar basal body from salmonella enterica.the bacterial flagellum is a motility organelle. the flagellum is composed of three main structures: the basal body as a rotary engine embedded in the cellular membranes and cell wall, the long external filament that acts as a propeller, and the hook acting as a universal joint that connects them. i describe protocols for the purification of the filament and hook-basal body from salmonella enterica serovar typhimurium.201728389946
fluorescent microscopy techniques to study hook length control and flagella formation.the bacterial flagellum is a sophisticated motility device made of about 30 different proteins and consists of three main structural parts: (1) a membrane-embedded basal body, (2) a flexible linking structure (the hook) that connects the basal body to, (3) the rigid filament that extends up to 10 μm from the cell surface. in salmonella enterica serovar typhimurium, the hook structure is controlled to a length of 55 nm by a molecular ruler protein, flik. only upon hook completion, flik induces a ...201728389943
fuel of the bacterial flagellar type iii protein export apparatus.the flagellar type iii export apparatus utilizes atp and proton motive force (pmf) across the cytoplasmic membrane as the energy sources and transports flagellar component proteins from the cytoplasm to the distal growing end of the growing structure to construct the bacterial flagellum beyond the cellular membranes. the flagellar type iii export apparatus coordinates flagellar protein export with assembly by ordered export of substrates to parallel with their order of the assembly. the export a ...201728389941
supplemental invasion of salmonella from the perspective of salmonella enterica serovars kentucky and typhimurium.critical to the development of salmonellosis in humans is the interaction of the bacterium with the epithelial lining of the gastrointestinal tract. traditional scientific reasoning held type iii secretion system (t3ss) as the virulence factor responsible for bacterial invasion. in this study, field-isolated salmonella enterica serovar kentucky and a known human pathogen salmonella enterica serovar typhimurium were mutated and evaluated for the invasion of human colorectal adenocarcinoma epithel ...201728381209
rna-seq-based analysis of drug-resistant salmonella enterica serovar typhimurium selected in vivo and in vitro.the aim of this study was to characterize the mechanism of fluoroquinolone (fq) resistance in salmonella typhimurium. we established the caenorhabditis elegans-salmonella typhimurium model to select for ciprofloxacin resistance in salmonella typhimurium colonizing c. elegans, generating the resistant strains tn4. gradient doses of ciprofloxacin were used to generate the resistant strain tw4 in vitro. rna sequencing was used to establish the whole-transcriptome profile of three strains of salmone ...201728380031
novel dna binding and regulatory activities for σ(54) (rpon) in salmonella enterica serovar typhimurium 14028s.the variable sigma (σ) subunit of the bacterial rna polymerase (rnap) holoenzyme, which is responsible for promoter specificity and open complex formation, plays a strategic role in the response to environmental changes. salmonella enterica serovar typhimurium utilizes the housekeeping σ(70) and five alternative sigma factors, including σ(54) the σ(54)-rnap differs from other σ-rnap holoenzymes in that it forms a stable closed complex with the promoter and requires atp hydrolysis by an activated ...201728373272
chemical composition and biological activities of helicteres vegae and heliopsis sinaloensis.helicteres vegae cristóbal (sterculiaceae) (hv) and heliopsis sinaloensis b.l. turner (asteraceae) (hs) are endangered and poorly studied plant species; related plants have been used against chronic-degenerative and infectious diseases. therefore, hv and hs could be sources of bioactive compounds against these illnesses.201728347185
epigallocatechin-3-gallate inhibits bacterial virulence and invasion of host cells.increasing antibiotic resistance and beneficial effects of host microbiota has motivated the search for anti-infective agents that attenuate bacterial virulence rather than growth. for example, we discovered that specific flavonoids such as baicalein and quercetin from traditional medicinal plant extracts could attenuate salmonella enterica serovar typhimurium type iii protein secretion and invasion of host cells. here, we show epigallocatechin-3-gallate from green tea extracts also inhibits the ...201728325635
silver nanoparticles against salmonella enterica serotype typhimurium: role of inner membrane dysfunction.the evolution of antibiotics-resistant bacteria is considered a major concern. to explore promising antibacterial materials and clarify their unknown mechanisms, the mode of action of silver nanoparticles (agnps) against salmonella enterica serotype typhimurium was investigated. we investigated the effect of agnps on the bacterial membrane. the n-phenyl-1-naphthylamine assay showed that the permeability of the outer membrane was not changed by treatment with agnps. the o-nitrophenyl-β-d-galactop ...201728321528
a novel hybrid plasmid carrying multiple antimicrobial resistance and virulence genes in salmonella enterica serovar dublin.virulence plasmids and antibiotic resistance plasmids are usually maintained separately in salmonella spp.; however, we report an instance of a hybrid plasmid (pn13-01125) in salmonella enterica serovar dublin. review of the complete sequence of the 172,265-bp plasmid suggests that pn13-01125 is comprised of the previously described psdvr and psh696_135 plasmids and that the mechanism of hybridization likely involves is6 (is26) insertion sequence elements. the plasmid has a low conjugation frequ ...201728320711
a potential role of salmonella infection in the onset of inflammatory bowel diseases.inflammatory bowel disease (ibd) includes a set of pathologies that result from a deregulated immune response that may affect any portion of the gastrointestinal tract. the most prevalent and defined forms of ibd are crohn's disease and ulcerative colitis. although the etiology of ibd is not well defined, it has been suggested that environmental and genetic factors contribute to disease development and that the interaction between these two factors can trigger the pathology. diet, medication use ...201728293241
foodborne salmonellosis in italy: characterization of salmonella enterica serovar typhimurium and monophasic variant 4,[5],12:i- isolated from salami and human patients.salmonella enterica serovar typhimurium (stm) and its monophasic variant 4,[5],12:i:- (vmstm) have been responsible for an increased number of foodborne infections in humans in europe in recent years. the aim of this study was to investigate the origin of three foodborne salmonellosis outbreaks that occurred in pavia province (lombardy region, northern italy) in 2010. phenotypic and genetic characteristics of the stm and vmstm isolates from patients and from food that were recovered in the frame ...201728291384
high binding affinity of repressor iolr avoids costs of untimely induction of myo-inositol utilization by salmonella typhimurium.growth of salmonella enterica serovar typhimurium strain 14028 with myo-inositol (mi) is characterized by a bistable phenotype that manifests with an extraordinarily long (34 h) and variable lag phase. when cells were pre-grown in minimal medium with mi, however, the lag phase shortened drastically to eight hours, and to six hours in the absence of the regulator iolr. to unravel the molecular mechanism behind this phenomenon, we investigated this repressor in more detail. flow cytometry analysis ...201728290506
gene expression values of pattern-recognition receptors in porcine leukocytes and their response to salmonella enterica serovar typhimurium infection.pattern-recognition receptors (prrs) recognize pathogen-associated molecular patterns and play an important role in triggering innate immune responses. prrs distribution and function is well documented in mice and humans, but studies in pigs are scarce. salmonella enterica serovar typhimurium is common pathogen found in pigs and was used as a model for interaction with prrs. this study investigated expression of prrs in porcine leukocyte subpopulations at the mrna level. eight subpopulations of ...201728285125
fermented rapeseed meal is effective in controlling salmonella enterica serovar typhimurium infection and improving growth performance in broiler chicks.the aim of present experiment was to assess the effects of fermented rapeseed meal (frsm) on salmonella enterica serovar typhimurium (s. typhimurium) colonization and growth performance in broiler chicks. two hundred forty day-old male cobb 500 broiler chicks were divided into six experimental treatments with four replicates and 10 birds per each. the treatments were including two positive and negative controls which birds received a basal corn-soybean diet as well as four others which birds rec ...201728284629
genomic heterogeneity of salmonella enterica serovar typhimurium bacteriuria from chronic infection.we sequenced the genomes of 14 sequential salmonella enterica serovar typhimurium isolates obtained over a five year period from a patient with persistent salmonella bacteriuria. the isolates formed five distinct lineages; two of which co-existed over four years. we inferred that the observed within-patient variation resulted from mutation events.201728279807
an association between decreasing incidence of invasive non-typhoidal salmonellosis and increased use of antiretroviral therapy, gauteng province, south africa, 2003-2013.hiv-infected persons are at increased risk of opportunistic infections, including invasive nontyphoidal salmonella (ints) infections; antiretroviral therapy (art) reduces this risk. we explored changing ints incidence associated with increasing art availability in south africa.201728264046
bacterial flagella grow through an injection-diffusion mechanism.the bacterial flagellum is a self-assembling nanomachine. the external flagellar filament, several times longer than a bacterial cell body, is made of a few tens of thousands subunits of a single protein: flagellin. a fundamental problem concerns the molecular mechanism of how the flagellum grows outside the cell, where no discernible energy source is available. here, we monitored the dynamic assembly of individual flagella using in situ labelling and real-time immunostaining of elongating flage ...201728262091
efflux pump overexpression contributes to tigecycline heteroresistance in salmonella enterica serovar typhimurium.bacterial heteroresistance has been identified in several combinations of bacteria and antibiotics, and it complicated the therapeutic strategies. tigecycline is being used as one of the optimal options for the treatment of infections caused by multidrug-resistant salmonella. this study investigated whether heterorresistance to tigecycline exists in a salmonella enterica serovar typhimurium strain harboring the oqxab-bearing inchi2 plasmid phxy0908. mic and population analyses were performed to ...201728261566
erratum for mccollister et al., whole-genome sequencing identifies in vivo acquisition of a blactx-m-27-carrying incfii transmissible plasmid as the cause of ceftriaxone treatment failure for an invasive salmonella enterica serovar typhimurium infection. 201728232307
scarless deletion of up to seven methyl-accepting chemotaxis genes with an optimized method highlights key function of chem in salmonella typhimurium.site-directed scarless mutagenesis is an essential tool of modern pathogenesis research. we describe an optimized two-step protocol for genome editing in salmonella enterica serovar typhimurium to enable multiple sequential mutagenesis steps in a single strain. the system is based on the λ red recombinase-catalyzed integration of a selectable antibiotics resistance marker followed by replacement of this cassette. markerless mutants are selected by expressing the meganuclease i-scei which induces ...201728212413
plant lectins conbr and cfl modulate expression toll-like receptors, pro-inflammatory cytokines and reduce the bacterial burden in macrophages infected with salmonella enterica serovar typhimurium.plant lectins have long been used in biomedical research as immunomodulators against tumor cells and microbial infections.201728190471
synthesis of l-cysteine derivatives containing stable sulfur isotopes and application of this synthesis to reactive sulfur metabolome.cysteine persulfide is an l-cysteine derivative having one additional sulfur atom bound to a cysteinyl thiol group, and it serves as a reactive sulfur species that regulates redox homeostasis in cells. here, we describe a rapid and efficient method of synthesis of l-cysteine derivatives containing isotopic sulfur atoms and application of this method to a reactive sulfur metabolome. we used bacterial cysteine syntheses to incorporate isotopic sulfur atoms into the sulfhydryl moiety of l-cysteine. ...201728189853
salmonella effector sopd2 interferes with rab34 function.many intracellular pathogens have evolved highly specialized mechanisms to isolate themselves from the host cell's innate immune response while still obtaining the necessary nutrients to survive. salmonella utilizes type 3 secretion systems (t3sss) to deliver bacterial proteins called effectors, across the encompassing salmonella containing vacuole (scv) membrane, to subvert the host's membrane trafficking pathways and alter other cellular processes. the salmonella pathogenicity island (spi)-2 e ...201728185347
elongation factor p restricts salmonella's growth by controlling translation of a mg(2+) transporter gene during infection.when a ribosome translates mrna sequences, the ribosome often stalls at certain codons because it is hard to translate. consecutive proline codons are such examples that induce ribosome stalling and elongation factor p (ef-p) is required for the stalled ribosome to continue translation at those consecutive proline codons. we found that ef-p is required for translation of the mgtb gene encoding a mg(2+) transporter in the mgtcbr virulence operon from the intracellular pathogen salmonella enterica ...201728181542
ceruloplasmin-derived peptide is the strongest regulator of oxidative stress and leukotriene synthesis in neutrophils.ceruloplasmin, an acute-phase protein, can affect the activity of leukocytes through its various enzymatic activities and protein-protein interactions (with lactoferrin, myeloperoxidase, eosinophil peroxidase, serprocidins, and 5-lipoxygenase (5-lox), among others). however, the molecular mechanisms of ceruloplasmin activity are not clearly understood. in this study, we tested the ability of two synthetic peptides, rpylkvfnpr (883-892) (p1) and rrpylkvfnprr (882-893) (p2), corresponding to the i ...201728177760
evaluation of the clinical and microbiological response to salmonella paratyphi a infection in the first paratyphoid human challenge model.to expedite the evaluation of vaccines against paratyphoid fever, we aimed to develop the first human challenge model of salmonella enterica serovar paratyphi a infection.201728158395
gut microbiota-mediated protection against diarrheal infections.the mammalian gut microbiota is a highly abundant and diverse microbial community that resides in the gastrointestinal tract. one major benefit that the gut microbiota provides to its host is colonization resistance-the ability to prevent colonization by foreign microbes, including diarrheal pathogens such as clostridium difficile , salmonella enterica serovar typhimurium and diarrheagenic escherichia coli .201728520994
antibacterial activity of crude extracts of some south african medicinal plants against multidrug resistant etiological agents of diarrhoea.this study evaluated the antibacterial activity of some plants used in folklore medicine to treat diarrhoea in the eastern cape province, south africa.201728629407
direct and inverted repeat stimulated excision (direx): simple, single-step, and scar-free mutagenesis of bacterial genes.the need for generating precisely designed mutations is common in genetics, biochemistry, and molecular biology. here, i describe a new λ red recombineering method (direct and inverted repeat stimulated excision; direx) for fast and easy generation of single point mutations, small insertions or replacements as well as deletions of any size, in bacterial genes. the method does not leave any resistance marker or scar sequence and requires only one transformation to generate a semi-stable intermedi ...201728854250
anti-aging activities of extracts from tunisian medicinal halophytes and their aromatic constituents.six medicinal halophytes widely represented in north africa and commonly used in traditional medicine were screened for pharmacological properties to set out new promising sources of natural ingredients for cosmetic or nutraceutical applications. thus, citrullus colocynthis, cleome arabica, daemia cordata, haloxylon articulatum, pituranthos scoparius and scorzonera undulata were examined for their in vitro antioxidant (dpph scavenging and superoxide anion-scavenging, β-carotene bleaching inhibit ...201728827992
comparative sequence analysis of multidrug-resistant inca/c plasmids from salmonella enterica.determinants of multidrug resistance (mdr) are often encoded on mobile elements, such as plasmids, transposons, and integrons, which have the potential to transfer among foodborne pathogens, as well as to other virulent pathogens, increasing the threats these traits pose to human and veterinary health. our understanding of mdr among salmonella has been limited by the lack of closed plasmid genomes for comparisons across resistance phenotypes, due to difficulties in effectively separating the dna ...201728824587
functional analysis of genes encoded by the locus of heat resistance (lhr) in escherichia coli.the locus of heat resistance (lhr) is a 15 - 19 kb genomic island conferring exceptional heat resistance to organisms in the family enterobacteriaceae including pathogenic strains of salmonella enterica and escherichia coli the complement of lhr-encoded genes that is necessary for heat resistance and the stress- or growth-phase induced expression of lhr-encoded genes are unknown. this study determined the contribution of the 7 lhr-encoded genes yfdx1gi, yfdx2, hdedgi, orf11, trxgi, kefb, and psi ...201728802266
novel plasmid-mediated colistin resistance mcr-4 gene in salmonella and escherichia coli, italy 2013, spain and belgium, 2015 to 2016.a novel mcr colistin resistance gene was identified in a strain of salmonella enterica, monophasic variant of serovar typhimurium (4,5,12:i:- ), isolated from a pig at slaughter in italy in 2013, and in escherichia coli strains collected during routine diagnostic of post-weaning diarrhoea in pigs from spain and belgium in 2015 and 2016. immediate implementation of mcr-screening including this novel gene variant is required for salmonella and e. coli from humans and food-producing animals in euro ...201728797329
construction of an inactivated typhoid vaccine candidate expressing escherichia coli heat-labile enterotoxin b subunit and evaluation of its immunogenicity in a murine model.typhoid fever caused by salmonella enterica serovar typhi has contributed to the global public health burden, particularly in developing countries. in this study, an s. typhi ghost was developed and its capacity as a vaccine candidate against typhoid fever was assessed.201728792376
rho protein: roles and mechanisms.at the end of the multistep transcription process, the elongating rna polymerase (rnap) is dislodged from the dna template either at specific dna sequences, called the terminators, or by a nascent rna-dependent helicase, rho. in escherichia coli, about half of the transcription events are terminated by the rho protein. rho utilizes its rna-dependent atpase activities to translocate along the mrna and eventually dislodges the rnap via an unknown mechanism. the transcription elongation factor nusg ...201728731845
serum albumin and osmolality inhibit bdellovibrio bacteriovorus predation in human serum.we evaluated the bactericidal activity of bdellovibrio bacteriovorus, strain hd100, within blood sera against bacterial strains commonly associated with bacteremic infections, including e. coli, klebsiella pneumoniae and salmonella enterica. tests show that b. bacteriovorus hd100 is not susceptible to serum complement or its bactericidal activity. after a two hour exposure to human sera, the prey populations decreased 15- to 7,300-fold due to the serum complement activity while, in contrast, the ...201728725056
role of the inner-membrane histidine kinase rcsc and outer-membrane lipoprotein rcsf in the activation of the rcs phosphorelay signal transduction system in escherichia coli.the rcs phosphorelay signal transduction system of escherichia coli controls genes for capsule production and many other envelope-related functions and is implicated in biofilm formation. the outer-membrane lipoprotein rcsf is an essential component of the rcs system. mislocalization of rcsf to the periplasm or the cytoplasmic membrane leads to high activation of the rcs system, suggesting that rcsf functions by interacting with the cytoplasmic membrane component(s) of the system in activating t ...201728691662
purification and characterization of an atpase gsia from salmonella enterica.the coding sequence of salmonella enterica gsia was cloned and expressed in e. coli. the protein was purified and atpase activity was characterized by nadh oxidation method. gsia exhibited optimum activity at 30°c and at ph 8 in tris/hcl buffer. gsia protein was stable at 20°c. 66% and 44% activity remained after incubation at 30°c and 40°c for 30 min. ph 7 and ph 9 incubation would obviously reduce the atpase activity. in vivo functionality of gsia was determined by constructing gene deletion s ...201728691022
super-cationic carbon quantum dots synthesized from spermidine as an eye drop formulation for topical treatment of bacterial keratitis.we have developed a one-step method to synthesize carbon quantum dots (cqdpas) from biogenic polyamines (pas) as an antibacterial agent for topical treatment of bacterial keratitis (bk). cqds synthesized by direct pyrolysis of spermidine (spd) powder through a simple dry heating treatment exhibit a solubility and yield much higher than those from putrescine and spermine. we demonstrate that cqds obtained from spds (cqdspds) possess effective antibacterial activities against non-multidrug-resista ...201728677399
host and pathogen copper-transporting p-type atpases function antagonistically during salmonella infection.copper is an essential yet potentially toxic trace element that is required by all aerobic organisms. a key regulator of copper homeostasis in mammalian cells is the copper-transporting p-type atpase atp7a, which mediates copper transport from the cytoplasm into the secretory pathway, as well as copper export across the plasma membrane. previous studies have shown that atp7a-dependent copper transport is required for killing phagocytosed escherichia coli in a cultured macrophage cell line. in th ...201728652309
emergence of drug resistant bacteria at the hajj: a systematic review.hajj is the annual mass gathering of muslims, and is a reservoir and potential source of bacterial transmission. the emergence of bacterial transmission, including multi-drug resistance (mdr) bacteria, during hajj has not been systematically assessed.201728652197
epigallocatechin gallate inhibits the type iii secretion system of gram-negative enteropathogenic bacteria under model conditions.epigallocatechin gallate (egcg), a major polyphenol in green tea, inhibits the type iii secretion system (t3ss) of enteropathogenic and enterohemorrhagic escherichia coli (epec and ehec, respectively), salmonella enterica serovar typhimurium, and yersinia pseudotuberculosis. the inhibitory effect causes the inhibition of hemolysis, cell invasion, cell adhesion and apoptosis, which are functions of the type iii secretion device. in the case of epec, espb accumulates in the cells. rt-pcr showed th ...201728651361
gut microbiota, nitric oxide, and microglia as prerequisites for neurodegenerative disorders.regulating fluctuating endogenous nitric oxide (no) levels is necessary for proper physiological functions. aberrant no pathways are implicated in a number of neurological disorders, including alzheimer's disease (ad) and parkinson's disease. the mechanism of no in oxidative and nitrosative stress with pathological consequences involves reactions with reactive oxygen species (e.g., superoxide) to form the highly reactive peroxynitrite, hydrogen peroxide, hypochloride ions and hydroxyl radical. n ...201728640632
atp-synthesis capacity of pulsed light-exposed bacteria.the ability of four different bacteria to synthesize new atp upon exposure to different doses of pulsed-light (pl) irradiation was investigated. the bacterial cells were pl treated on a gel surface, resuspended in phosphate buffered saline (pbs) and subsequently incubated in tryptic soy broth (tsb) at 37°c. cellular atp levels were monitored during a 2h incubation period and compared to the respective colony count data. although pl affected atp production in a dose dependent manner, the results ...201728629639
anaerobic cysteine degradation and potential metabolic coordination in salmonella enterica and escherichia coli.salmonella enterica has two cyur-activated enzymes that degrade cysteine, i.e., the aerobic cdsh and an unidentified anaerobic enzyme; escherichia coli has only the latter. to identify the anaerobic enzyme, transcript profiling was performed for e. coli without cyur and with overexpressed cyur thirty-seven genes showed at least 5-fold changes in expression, and the cyupa (formerly yhaom) operon showed the greatest difference. homology suggested that cyup and cyua represent a cysteine transporter ...201728607157
comparison of methods for detection of plasmid-mediated and chromosomally encoded colistin resistance in enterobacteriaceae.because of the emergence of plasmid-mediated (mcr-1 and mcr-2 genes) and chromosomally encoded colistin resistance, reliable methods for detecting colistin resistance/susceptibility in routine laboratories are required. we evaluated the respective performances of the bd phoenix automated system, the newly developed rapid polymyxin np test and the broth microdilution (bmd) reference method to detect colistin resistance in enterobacteriaceae, and particularly those producing mcr-1 and mcr-2.201728606644
oxidation of phosphorothioate dna modifications leads to lethal genomic instability.genomic modification by sulfur in the form of phosphorothioate (pt) is widespread among prokaryotes, including human pathogens. apart from its physiological functions, pt sulfur has redox and nucleophilic properties that suggest effects on bacterial fitness in stressful environments. here we show that pts are dynamic and labile dna modifications that cause genomic instability during oxidative stress. in experiments involving isotopic labeling coupled with mass spectrometry, we observed sulfur re ...201728604692
bdm-mediated regulation of flagellar biogenesis in escherichia coli and salmonella enterica serovar typhimurium.synthesis of the flagellar apparatus in escherichia coli is mediated via complex regulatory pathways. a previous study indicated that the protein encoded by the biofilm-dependent modulation (bdm) gene is linked closely with a regulatory pathway for flagellar assembly. however, the specific role of bdm in flagellar biogenesis remains unknown. herein, we showed that bdm interacts with flgm and inhibits its function as an anti-σ28 factor, which induces the transcription of flagellar late-class gene ...201728603807
a functional metagenomic analysis of tetracycline resistance in cheese bacteria.metagenomic techniques have been successfully used to monitor antibiotic resistance genes in environmental, animal and human ecosystems. however, despite the claim that the food chain plays a key role in the spread of antibiotic resistance, metagenomic analysis has scarcely been used to investigate food systems. the present work reports a functional metagenomic analysis of the prevalence and evolution of tetracycline resistance determinants in a raw-milk, blue-veined cheese during manufacturing ...201728596758
a versatile toolbox for the control of protein levels using n(ε)-acetyl-l-lysine dependent amber suppression.the analysis of the function of essential genes in vivo depends on the ability to experimentally modulate levels of their protein products. current methods to address this are based on transcriptional or post-transcriptional regulation of mrnas, but approaches based on the exploitation of translation regulation have so far been neglected. here we describe a toolbox, based on amber suppression in the presence of n(ε)-acetyl-l-lysine (ack), for translational tuning of protein output. we chose the ...201728594177
the rcs-regulated colanic acid capsule maintains membrane potential in salmonella enterica serovar typhimurium.the rcs phosphorelay and psp (phage shock protein) systems are envelope stress responses that are highly conserved in gammaproteobacteria. the rcs regulon was found to be strongly induced during metal deprivation of salmonella enterica serovar typhimurium lacking the psp response. nineteen genes activated by the rcsa-rcsb response regulator make up an operon responsible for the production of colanic acid capsular polysaccharide, which promotes biofilm development. despite more than half a centur ...201728588134
the ubik protein is an accessory factor necessary for bacterial ubiquinone (uq) biosynthesis and forms a complex with the uq biogenesis factor ubij.ubiquinone (uq), also referred to as coenzyme q, is a widespread lipophilic molecule in both prokaryotes and eukaryotes in which it primarily acts as an electron carrier. eleven proteins are known to participate in uq biosynthesis in escherichia coli, and we recently demonstrated that uq biosynthesis requires additional, nonenzymatic factors, some of which are still unknown. here, we report on the identification of a bacterial gene, yqic, which is required for efficient uq biosynthesis, and whic ...201728559279
phage applications for improving food safety and infection control in egypt.the study investigated the use of bacteriophages to control bacterial contamination of chicken skin, eggs, tomatoes and meat.201728557189
inhibitor-assisted high-pressure inactivation of bacteria in skim milk.the combined inactivation effects of high hydrostatic pressure (hhp) and antimicrobial compounds (potassium sorbate and ε-polylysine [ε-pl]) on 4 different bacterial strains present in skim milk and the effect of these treatments on milk quality were investigated in this study. hhp treatment at 500 mpa for 5 min reduced the populations of escherichia coli, salmonella enterica typhimurium, listeria monocytogenes, and staphylococcus aureus from 6.5 log colony-forming units (cfus) or higher to less ...201728556370
label-free biosensing of salmonella enterica serovars at single-cell level.the emerging nanotechnologies have greatly facilitated the development of label-free biosensors. the atomic force microscopy (afm) has been used to study the molecular mechanism of the reactions for protein and aptamers. the surface plasmon resonance (spr) have been used in fast detections of various pathogens such as bacteria. this study used both afm and spr to investigate the complex reactions between aptamers and outer membrane proteins (omps) on the surface of s. typhimurium.201728514955
anco3, a new member of the emerging family of phage-like plasmids.a phage-like plasmid isolated from a clinical isolate of salmonella enterica serovar derby has strong nucleotide sequence identity to the phage-like plasmids pstm_phi isolated from salmonella enterica serovar typhimurium l495, anco1 and anco2 from escherichia coli 243 and escherichia coli 244, and the virulent salmonella-specific ssu5 bacteriophage.201728495760
identification of the potentiating mutations and synergistic epistasis that enabled the evolution of inter-species cooperation.microbes often engage in cooperation through releasing biosynthetic compounds required by other species to grow. given that production of costly biosynthetic metabolites is generally subjected to multiple layers of negative feedback, single mutations may frequently be insufficient to generate cooperative phenotypes. synergistic epistatic interactions between multiple coordinated changes may thus often underlie the evolution of cooperation through overproduction of metabolites. to test the import ...201728493869
attachment and biofilm formation by selected strains of salmonella enterica and entrohemorrhagic escherichia coli of fresh produce origin.this study compared the abilities of selected salmonella enterica and enterohemorrhagic escherichia coli (ehec) strains of fresh produce origin to form biofilms on polystyrene surface and to attach to alfalfa and bean sprouts. each of the 7 s. enterica and 4 ehec inocula (2 ml; 10(7) cfu/ml) was placed in 6 different broths in 24-well polystyrene tissue culture plates at 28 °c for 1 to 7 d. developed biofilms were quantified using the crystal violet binding assay. in a separate experiment, alfal ...201728493317
the c-terminus of ribosomal protein us4 contributes to small ribosomal subunit biogenesis and the fidelity of translation.ribosomal protein us4 is an essential ribosomal component involved in multiple functions, including mrna decoding. structural analyses indicate that during decoding, the interface between the c-terminus of us4 and protein us5 is disrupted and in agreement with this, c-terminal us4 truncation mutants are readily isolated on the basis of their increased miscoding phenotypes. the same mutants can also display defects in small subunit assembly and 16s rrna processing and some are temperature sensiti ...201728483689
the response to 2-aminoacrylate differs in escherichia coli and salmonella enterica, despite shared metabolic components.the metabolic network of an organism includes the sum total of the biochemical reactions present. in microbes, this network has an impeccable ability to sense and respond to perturbations caused by internal or external stimuli. the metabolic potential (i.e., network structure) of an organism is often drawn from the genome sequence, based on the presence of enzymes deemed to indicate specific pathways. escherichia coli and salmonella enterica are members of the enterobacteriaceae family of gram-n ...201728461448
prevalence and pathogen load of campylobacter spp., salmonella enterica and escherichia coli o157/o145 serogroup in sheep faeces collected at sale yards and in abattoir effluent in western australia.develop a multiplex quantitative pcr assay to investigate the prevalence and shedding of escherichia coli o157/o145, salmonella spp. and campylobacter spp. in sheep at sale yards and abattoirs.201728444752
the legacy of genetic analysis advances contemporary research with escherichia coli k-12 and salmonella enterica serovar typhimurium lt2.escherichia coli k-12 and salmonella enterica serovar typhimurium lt2 became standard organisms for genetic analysis during the truman administration. half a century later, genetic analysis with these strains had become an art form, interpreted through 23 articles in the ambitious two-volume masterpiece edited by the late fred neidhardt and colleagues. these legacy articles now are available through ecosal plus, so as to inform and inspire contemporary genetic analyses in these standard organism ...201728443537
transport and attenuation of salmonella enterica, fecal indicator bacteria and a poultry litter marker gene are correlated in soil columns.millions of tons of fecal-contaminated poultry litter are applied to u.s. agricultural fields annually. precipitation and irrigation facilitate transport of fecal-derived pathogens and fecal indicator bacteria (fib) to groundwater. the goal of this study was to compare transport of pathogens, fib, and a microbial source tracking marker gene for poultry litter (la35) in a simulated soil-to-groundwater system. nine laboratory soil columns containing four different soil types were used to evaluate ...201728441599
genomic analysis of factors associated with low prevalence of antibiotic resistance in extraintestinal pathogenic escherichia coli sequence type 95 strains.extraintestinal pathogenic escherichia coli (expec) strains belonging to multilocus sequence type 95 (st95) are globally distributed and a common cause of infections in humans and domestic fowl. st95 isolates generally show a lower prevalence of acquired antimicrobial resistance than other pandemic expec lineages. we took a genomic approach to identify factors that may underlie reduced resistance. we fully assembled genomes for four st95 isolates representing the four major fimh-based lineages w ...201728405633
convergence of dna methylation and phosphorothioation epigenetics in bacterial genomes.explosive growth in the study of microbial epigenetics has revealed a diversity of chemical structures and biological functions of dna modifications in restriction-modification (r-m) and basic genetic processes. here, we describe the discovery of shared consensus sequences for two seemingly unrelated dna modification systems, (6m)a methylation and phosphorothioation (pt), in which sulfur replaces a nonbridging oxygen in the dna backbone. mass spectrometric analysis of dna from escherichia coli b ...201728400512
natural product discovery from the human microbiome.human-associated microorganisms have the potential to biosynthesize numerous secondary metabolites that may mediate important host-microbe and microbe-microbe interactions. however, there is currently a limited understanding of microbiome-derived natural products. a variety of complementary discovery approaches have begun to illuminate this microbial "dark matter," which will in turn allow detailed mechanistic studies of the effects of these molecules on microbiome and host. herein, we review re ...201728389564
a randomized trial to assess the effect of fluoroquinolone metaphylaxis on the fecal prevalence and quinolone susceptibilities of salmonella and campylobacter in feedlot cattle.the study objective was to determine effects of fluoroquinolone metaphylaxis on fecal prevalence of salmonella and campylobacter and fecal prevalence of quinolone-resistant salmonella and campylobacter in feedlot cattle. on day 0, cattle (n = 288) at risk for bovine respiratory disease (brd) were randomly assigned to either a nontreated control pen (12 pens) or a fluoroquinolone-treated (enrofloxacin; baytril(®) 100) pen (12 pens). rectal fecal samples were collected from cattle on days 0, 7, 14 ...201728768141
development and evaluation of a multiple-locus variable-number tandem-repeats analysis assay for subtyping salmonella typhi strains from sub-saharan africa.molecular epidemiological investigations of the highly clonal salmonella enterica subspecies enterica serovar typhi (s. typhi) are important in outbreak detection and in tracking disease transmission. in this study, we developed and evaluated a multiple-locus variable-number tandem-repeats (vntr) analysis (mlva) assay for characterization of s. typhi isolates from sub-saharan africa.201728721851
draft genome sequence of the tumor-targeting salmonella enterica serovar typhimurium strain sl7207.salmonella enterica serovar typhimurium strain sl7207 is a genetically modified derivative of strain sl1344, which preferentially accumulates in tumors and can be used as a vehicle for tissue-specific gene delivery in vivo here, we report the draft genome sequence of sl7207, confirming a purported aroa deletion and four single-nucleotide polymorphisms compared to sl1344.201728153911
quantitative proteomics charts the landscape of salmonella carbon metabolism within host epithelial cells.we performed a proteomic survey of salmonella enterica serovar typhimurium during infection of host epithelial cells. our data reveal substantial metabolic reshuffling of salmonella in the host in addition to severe degeneration of bacterial flagella and chemotaxis systems. the large-scale quantitative data allowed us to chart an overview of intracellular salmonella carbon metabolism. notably, we found preferential utilization of glycolysis, the pentose phosphate pathway, mixed acid fermentation ...201728152601
mcr-1-harboring salmonella enterica serovar typhimurium sequence type 34 in pigs, china.we detected the mcr-1 gene in 21 (14.8%) salmonella isolates from pigs at slaughter; 19 were serovar typhimurium sequence type 34. the gene was located on inchi2-like plasmids that also harbored incf replicons and lacked a conjugative transfer region. these findings highlight the need to prevent further spread of colistin resistance in animals and humans.201728098547
use of carvacrol, thymol, and eugenol for biofilm eradication and resistance modifying susceptibility of salmonella enterica serovar typhimurium strains to nalidixic acid.the aims of the study was to evaluate the antibacterial susceptibility and the biofilm eradication of three natural compounds carvacrol (car), thymol (th) and eugenol (eug), alone or in combination with nalidixic acid (na) against twelve salmonella typhimurium strains. the minimum inhibitory concentration (mic) and the minimum biofilm eradication concentration (bec50) of the tested compounds (car, th and eug) and their combinations with na were evaluated. in order to assess whether these bacteri ...201728062292
erratum to: studies on the therapeutic effect of propolis along with standard antibacterial drug in salmonella enterica serovar typhimurium infected balb/c mice. 201728056925
dynamics of salmonella shedding and welfare of hens in free-range egg production systems.the current study investigated the effect of environmental stressors (i.e., weather changes) on salmonella shedding in free-range production systems and the correlations with behavioral and physiological measures (i.e., fecal glucocorticoid metabolites). this involved longitudinal and point-in-time surveys of salmonella shedding and environmental contamination on four commercial free-range layer farms. the shedding of salmonella was variable across free-range farms and in different seasons. ther ...201728039133
identification of a stable complex between a [nife]-hydrogenase catalytic subunit and its maturation protease.salmonella enterica serovar typhimurium has the ability to use molecular hydrogen as a respiratory electron donor. this is facilitated by three [nife]-hydrogenases termed hyd-1, hyd-2, and hyd-5. hyd-1 and hyd-5 are homologous oxygen-tolerant [nife]-hydrogenases. a critical step in the biosynthesis of a [nife]-hydrogenase is the proteolytic processing of the catalytic subunit. in this work, the role of the maturation protease encoded within the hyd-5 operon, hydd, was found to be partially compl ...201728029689
hysteresis in myo-inositol utilization by salmonella typhimurium.growth of salmonella enterica serovar typhimurium strain 14028 with myo-inositol (mi) as the sole carbon and energy source is characterized by a bistable phenotype that manifests in a growth phenotype with an extraordinarily long and length-variable lag phase. however, in the presence of hydrogen carbonate, in the absence of iolr that represses the mi degradation pathway, or if cells are already adapted to minimal medium (mm) with mi, the lag phase is drastically shortened, and the bistable phen ...201728027601
functional relatedness in the inv/mxi-spa type iii secretion system family.type iii secretion systems (t3sss) are structurally conserved nanomachines that span the inner and outer bacterial membranes, and via a protruding needle complex contact host cell membranes and deliver type iii effector proteins. t3ss are phylogenetically divided into several families based on structural basal body components. here we have studied the evolutionary and functional conservation of four t3ss proteins from the inv/mxi-spa family: a cytosolic chaperone, two hydrophobic translocators t ...201727997726
autophagic targeting and avoidance in intracellular bacterial infections.eukaryotic cells use autophagy to break down and recycle components such as aggregated proteins and damaged organelles. research in the past decade, particularly using salmonella enterica serovar typhimurium as a model pathogen, has revealed that autophagy can also target invading intracellular bacterial pathogens for degradation. however, many bacterial pathogens have evolved mechanisms that allow for evasion of the autophagic pathway, such as motility or direct and irreversible cleavage of pro ...201727984783
using in vitro dynamic models to evaluate fluoroquinolone activity against emergence of resistant salmonella enterica serovar typhimurium.the objectives of this study were to determine pharmacokinetic/pharmacodynamic (pk/pd) indices of fluoroquinolones that minimize the emergence of resistant salmonella enterica serovar typhimurium (s typhimurium) using in vitro dynamic models and to establish mechanisms of resistance. three fluoroquinolones, difloxacin (dif), enrofloxacin (enr), and marbofloxacin (mar), at five dose levels and 3 days of treatment were simulated. bacterial killing-regrowth kinetics and emergence of resistant bacte ...201727895011
genetic characterization of the galactitol utilization pathway of salmonella enterica serovar typhimurium.galactitol degradation by salmonellae remains underinvestigated, although this metabolic capability contributes to growth in animals (r. r. chaudhuri et al., plos genet 9:e1003456, 2013, https://doi.org/10.1371/journal.pgen.1003456). the genes responsible for this metabolic capability are part of a 9.6-kb gene cluster that spans from gaty to gatr (stm3253 to stm3262) and encodes a phosphotransferase system, four enzymes, and a transporter of the major facilitator superfamily. genome comparison r ...201727956522
salmonella meningitis associated with monocyte infiltration in mice.in the current study, we examined the ability of salmonella enterica serovar typhimurium to infect the central nervous system and cause meningitis following the natural route of infection in mice. c57bl/6j mice are extremely susceptible to systemic infection by salmonella typhimurium because of loss-of-function mutations in nramp1 (slc11a1), a phagosomal membrane protein that controls iron export from vacuoles and inhibits salmonella growth in macrophages. therefore, we assessed the ability of s ...201727955815
complex genetics architecture contributes to salmonella resistance in acb60 mice.human infection with salmonella is of global public health concern. in low- and middle-income countries, salmonella infection is a major source of disease in terms of both mortality and morbidity, while in high-income nations, the pathogen is an ongoing threat to food security. the outcome of infection with salmonella enterica serovar typhimurium (salmonella typhimurium) in mouse models is dependent upon a coordinated and complex immune response. a panel of recombinant congenic strains (rcs) der ...201727913859
measurement of salmonella enterica internalization and vacuole lysis in epithelial cells.establishment of an intracellular niche within mammalian cells is key to the pathogenesis of the gastrointestinal bacterium, salmonella enterica serovar typhimurium (s. typhimurium). here we will describe how to study the internalization of s. typhimurium into human epithelial cells using the gentamicin protection assay. the assay takes advantage of the relatively poor penetration of gentamicin into mammalian cells; internalized bacteria are effectively protected from its antibacterial actions. ...201727815887
incidence and genetic bases of nitrofurantoin resistance in clinical isolates of two successful multidrug-resistant clones of salmonella enterica serovar typhimurium: pandemic "dt 104" and puo-stvr2.in this study, the incidence and genetic bases of nitrofurantoin resistance were established for clinical isolates of two successful clones of salmonella enterica serovar typhimurium, the pandemic "dt 104" and the puo-stvr2 clone. a total of 61 "dt 104" and 40 puo-stvr2 isolates recovered from clinical samples during 2008-2014 and assigned to different phage types, were tested for nitrofurantoin susceptibility. as previously shown for older isolates, all newly tested puo-stvr2 isolates were high ...201727809653
the iron-sulfur cluster sensor iscr is a negative regulator of spi1 type iii secretion system in salmonella enterica.iron-sulfur (fe-s)-containing proteins contribute to various biological processes, including redox reactions or regulation of gene expression. living organisms have evolved by developing distinct biosynthetic pathways to assemble these clusters, including iron sulfur cluster (isc) and sulfur mobilization (suf). salmonella enterica serovar typhimurium is an intracellular pathogen responsible for a wide range of infections, from gastroenteritis to severe systemic diseases. salmonella possesses all ...201727704705
efficacy evaluation of commercial disinfectants by using salmonella enterica serovar typhimurium as a test organism.the efficacies of six commercial disinfectants were evaluated by using salmonella enterica serovar typhimurium under simulated natural conditions such as sub-zero temperature, short disinfecting time, and surface type (uneven or smooth). we used a suspensionmodel test to determine the disinfecting efficacy under varying contact times (1, 5, 10, and 30 min) and temperatures (25°c, 4°c, 0°c, and -10°c). the bactericidal effect according to surface structure was measured by using a carriermodel tes ...201727586462
comparing tio2 photocatalysis and uv-c radiation for inactivation and mutant formation of salmonella typhimurium ta102.salmonellosis is one of the most common causes of foodborne bacterial human disease worldwide, and the emergence of multidrug-resistant (mdr) strains of salmonella enterica serovar typhimurium (s. typhimurium) was associated to the incidence of invasive salmonellosis. the objective of the present work was to investigate the effects of the tio2 photocatalysis process in terms of both bacteria inactivation and the emergence of mutants, on s. typhimurium ta102 water suspensions. the tio2 photocatal ...201727796997
salmonella and the inflammasome: battle for intracellular dominance.inflammasomes are macromolecular cytoplasmic complexes that act as signaling platforms for the activation of inflammatory caspases. their activation triggers the processing and secretion of the pro-inflammatory cytokines il-1β and il-18, as well as the induction of a specialized form of inflammatory cell death termed pyroptosis. here, we review the mechanisms of inflammasome activation triggered by the intracellular pathogen salmonella enterica serovar typhimurium. we highlight the different inf ...201727460804
Refresh
firstprev
12345678910...
nextlast
Displaying items 501 - 600 of 11731