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effect of inoculum preparation procedure and storage time and temperature on the fate of listeria monocytogenes on inoculated salami.although dry/semidry fermented sausages are characterized as being of low-to-moderate risk for human listeriosis on a per-serving and per-annum basis, data are lacking relative to the fate of postprocessing listeria monocytogenes contamination during storage of such products. this study evaluated the effect of inoculum preparation and storage conditions on the fate of l. monocytogenes on vacuum-packaged salami. commercially produced salami was sliced and inoculated (4 +/- 1.3 log cfu/ cm2) with ...200818389691
antibacterial efficiency of spanish satureja montana essential oil against listeria monocytogenes among natural flora in minced pork.the purpose of this study was to examine the effectiveness of winter savory (satureja montana) essential oil (eo) for control of growth and survival of experimentally inoculated listeria monocytogenes serovar 4b (10(4) cfu/g) among natural flora in minced pork. eos of french thyme (thymus vulgaris f) and rosemary (rosmarinus officinalis) cultivated in the same region of aragon (northeastern spain) were used as reference ingredients. the eos obtained by hydrodistillation were added at concentrati ...200818389692
low prevalence of listeria monocytogenes in cull sows and pork.the goal of this study was to determine the prevalence of listeria monocytogenes in sows slaughtered at a single midwestern plant on two occasions (trial 1, n = 179 sows; trial 2, n = 160 sows). fecal samples collected antemortem (trial 1) as well as animal tissues, and carcass swabs collected at the abattoir (trials 1 and 2) were analyzed. eight isolates of l. monocytogenes were recovered from five samples that represented 0.18% of the total samples (n = 2,775). in trial 1, l. monocytogenes was ...200818389698
effect of acidified sodium chlorite, chlorine, and acidic electrolyzed water on escherichia coli o157:h7, salmonella, and listeria monocytogenes inoculated onto leafy greens.recent foodborne outbreaks implicating spinach and lettuce have increased consumer concerns regarding the safety of fresh produce. while the most common commercial antimicrobial intervention for fresh produce is wash water containing 50 to 200 ppm chlorine, this study compares the effectiveness of acidified sodium chlorite, chlorine, and acidic electrolyzed water for inactivating escherichia coli o157:h7, salmonella, and listeria monocytogenes inoculated onto leafy greens. fresh mixed greens wer ...200818389712
use of uv light for the inactivation of listeria monocytogenes and lactic acid bacteria species in recirculated chill brines.ready-to-eat meat products have been implicated in several foodborne listeriosis outbreaks. microbial contamination of these products can occur after thermal processing when products are chilled in salt brines. the objective of this study was to evaluate uv radiation on the inactivation of listeria monocytogenes and lactic acid bacteria in a model brine chiller system. two concentrations of brine (7.9% [wt/wt] or 13.2% [wt/wt]) were inoculated with a approximately 6.0 log cfu/ml cocktail of l. m ...200818389713
influence of peroxyacetic acid and nisin and coculture with enterococcus faecium on listeria monocytogenes biofilm formation.biofilm formation is a matter of concern in food industries because biofilms facilitate the survival of pathogenic bacteria such as listeria monocytogenes, which may contaminate food-processing equipment and products. in this study, nisin and two enterococcus faecium strains were evaluated for their effect on biofilm formation by l. monocytogenes cultured in brain heart infusion broth and on stainless steel coupons. elimination of preformed l. monocytogenes biofilms by peroxyacetic acid also was ...200818389714
microbial growth and the effects of mild acidification and preservatives in refrigerated sweet potato puree.refrigerated sweet potato puree is a convenient form of sweet potato that can be used as an ingredient in formulated foods. the microbiology of refrigerated sweet potato puree during storage for up to 5 weeks was evaluated. because the puree was made by comminuting steam-cooked sweet potatoes before refrigeration, no naturally occurring vegetative bacterial cells were detected during a 4-week period of refrigerated storage at 4 degrees c. however, if postprocessing microbial contamination of the ...200818389715
the long isoform of cellular flip is essential for t lymphocyte proliferation through an nf-kappab-independent pathway.although the long isoform of cellular flip (c-flip(l)) has been implicated in tcr-mediated signaling, its role in t cell proliferation remains controversial. some studies have demonstrated that overexpression of c-flip(l) promotes t cell proliferation and nf-kappab activation, whereas others have reported that c-flip(l) overexpression has no effect or even inhibits t cell proliferation. to establish the role of c-flip(l) in t lymphocyte proliferation, we have generated a conditional knockout mou ...200818390734
protein kinase c-theta critically regulates the proliferation and survival of pathogen-specific t cells in murine listeriosis.protein kinase c-theta (pkc-theta) is essential for the activation of t cells in autoimmune disorders, but not in viral infections. to study the role of pkc-theta in bacterial infections, pkc-theta(-/-) and wild-type mice were infected with listeria monocytogenes (lm). in primary and secondary listeriosis, the numbers of lm-specific cd8 and cd4 t cells were drastically reduced in pkc-theta(-/-) mice, resulting in increased cfus in spleen and liver of both pkc-theta(-/-) c57bl/6 and balb/c mice. ...200818390745
acquisition of the vacuolar atpase proton pump and phagosome acidification are essential for escape of francisella tularensis into the macrophage cytosol.the francisella tularensis-containing phagosome (fcp) matures to a late-endosome-like phagosome prior to bacterial escape into the cytosols of macrophages, where bacterial proliferation occurs. our data show that within the first 15 min after infection of primary human monocyte-derived macrophages (hmdms), approximately 90% of the fcps acquire the proton vacuolar atpase (vatpase) pump and the lysomotropic dye lysotracker, which concentrates in acidic compartments, similar to phagosomes harboring ...200818390995
blood monocytes: distinct subsets, how they relate to dendritic cells, and their possible roles in the regulation of t-cell responses.monocytes can have important effects on the polarization and expansion of lymphocytes and may contribute to shaping primary and memory t-cell responses in humans and mice. however, their precise contribution in terms of cellular subsets and the molecular mechanisms involved remains to be determined. mouse monocytes originate from a bone marrow progenitor, the macrophage and dc precursor (mdp), which also gives rise to conventional dendritic cells through a separate differentiation pathway. mouse ...200818392044
processing plant persistent strains of listeria monocytogenes appear to have a lower virulence potential than clinical strains in selected virulence models.listeria monocytogenes is an important foodborne bacterial pathogen that can colonize food processing equipment. one group of genetically similar l. monocytogenes strains (rapd type 9) was recently shown to reside in several independent fish processing plants. persistent strains are likely to contaminate food products, and it is important to determine their virulence potential to evaluate risk to consumers. we compared the behaviour of food processing persistent and clinical l. monocytogenes str ...200818394737
listeria comet tails: the actin-based motility machinery at work.listeria monocytogenes is a master of mimicry that uses the host cell actin system both to move within the cytoplasm of infected cells and for cell-to-cell spread. recent studies of listeria and similarly acting pathogens have generated leaps in our understanding of the actin-based force producing machinery. this machinery is essential for most motile properties of cells, not least for cell migration. in a minimal configuration, it consists of the arp2/3-complex, ena-vasp proteins, cofilin, capp ...200818396046
importance of murine vdelta1gammadelta t cells expressing interferon-gamma and interleukin-17a in innate protection against listeria monocytogenes infection.murine gammadelta t cells participate in the innate immune response against infection by an intracellular pathogen listeria monocytogenes. vdelta1+gammadelta t cells coexpressing vgamma6 are a major gammadelta t-cell subpopulation induced at an early stage of l. monocytogenes infection in the livers of infected mice. to investigate the protective role of the vgamma6/vdelta1+gammadelta t cells against l. monocytogenes infection, vdelta1 gene-deficient (vdelta1-/-) mice were analysed because these ...200818397272
interactions of some common pathogenic bacteria with acanthamoeba polyphaga.protozoan grazing is a major trophic pathway whereby the biomass re-enters the food web. nonetheless, not all bacteria are digested by protozoa and the number known to evade digestion, resulting in their environmental augmentation, is increasing. we investigated the interactions of bacillus cereus, enterococcus faecalis, enteropathogenic escherichia coli (epec), listeria monocytogenes, salmonella enterica serovar typhimurium, and methicillin-sensitive staphylococcus aureus (mssa), with the amoeb ...200818399997
prodrug converting enzyme gene delivery by l. monocytogenes.listeria monocytogenes is a highly versatile bacterial carrier system for introducing protein, dna and rna into mammalian cells. the delivery of tumor antigens with the help of this carrier into tumor-bearing animals has been successfully carried out previously and it was recently reported that l. monocytogenes is able to colonize and replicate within solid tumors after local or even systemic injection.200818402662
effect of water activity on inactivation of listeria monocytogenes and lactate dehydrogenase during high pressure processing.the aim of this study was to investigate the effect of water activity (aw) on the inactivation of listeria monocytogenes and lactate dehydrogenase (ldh) during high pressure processing (hpp). for microbial inactivation lyophilized cells of l. monocytogenes 19,115 were left dry or were suspended in 10 ml of 0.1% peptone water, 10 ml of glycerol, or mixtures of glycerol and peptone water. all samples of various aws were high pressure (hp) processed at ambient temperature at 600 mpa for 300 s. foll ...200818403036
effective t-cell immune responses in the absence of the serine/threonine kinase rip2.the serine/threonine kinase rip2 has been reported to be essential for nod1 and nod2 mediated cell activation, and has been suggested to play a role in the signaling cascade downstream of the t-cell receptor. we sought to ascertain the exact role of rip2 in t-helper cell differentiation and cd8+ t-cell effector function in vivo and in vitro. in contrast to previous reports, we found that rip2-deficient t cells did not exhibit impaired proliferation upon tcr engagement in vitro, and differentiati ...200818403232
lipopolysaccharide sensing an important factor in the innate immune response to gram-negative bacterial infections: benefits and hazards of lps hypersensitivity.in this review, we summarize our investigations concerning the differential importance of cd14 and lbp in toll-like receptor 4 (tlr4)/myeloid differentiation protein-2 (md-2)-mediated signaling by smooth and rough-form lipopolysaccharide (lps) chemotypes and include the results obtained in studies with murine and human tlr4-transgenic mice. furthermore, we present more recent data on the mechanisms involved in the induction of lps hypersensitivity by bacterial and viral infections and on the rea ...200818406367
fusogenicity of membranes: the impact of acid sphingomyelinase on innate immune responses.acid sphingomyelinase (asmase) has been implemented in cellular signaling mainly because its reaction product, ceramide, has been assumed to be a mediator within signaling pathways. our studies of three independent infection systems show that asmase is required for phago-lysosomal fusion in macrophages infected with listeria monocytogenes, for exocytosis of secretory lysosomes by lymphocytic choriomeningitis virus-specific cytotoxic t cells, and for generation of multinucleated giant cells in gr ...200818406376
immediate lymphotoxin beta receptor-mediated transcriptional response in host defense against l. monocytogenes.the lymphotoxin beta receptor (ltbetar) mediates crucial signals in host defense against intracellular bacteria and viruses. mice deficient in ltbetar readily succumb to infections with listeria monocytogenes, mycobacterium tuberculosis and murine cytomegalovirus (mcmv). ltbetar has been shown to be important for the early induction of interferon (ifn) beta after infection with mcmv. however, up to now, it is not known which host effector molecules are induced in cells of the innate immune syste ...200818406380
modelling the effect of the redox potential and ph of heating media on listeria monocytogenes heat resistance.study the effect of redox potential and ph of the heating media on listeria monocytogenes heat resistance and model its action at fixed temperature.200818410341
investigation into the effect of detergents on disinfectant susceptibility of attached escherichia coli and listeria monocytogenes.investigate the effect of detergent treatment on susceptibility of attached escherichia coli and listeria monocytogenes to subsequent disinfectant treatment.200818410344
epstein-barr virus-induced gene 3 negatively regulates il-17, il-22 and rorgamma t.epstein-barr virus-induced gene 3 (ebi3) associates with p28 to form il-27 and with il-12p35 to form il-35. il-27ralpha(-/-) mice studies indicate that il-27 negatively regulates th17 cell differentiation. however, no ebi3, p28 or p35-deficiency studies that directly address the role of ebi3, p28 or p35 on th17 cells have been done. here, we demonstrate that spleen cells derived from ebi3(-/-) mice produce significantly higher levels of il-17 as well as il-22 upon stimulation with ova. in vitro ...200818412165
fate of foodborne pathogens on green onions and tomatoes by electrolysed water.to investigate the efficacy of electrolysed water (ew) in killing escherichia coli o157:h7, salmonella typhimurium and listeria monocytogenes on the surfaces of spot-inoculated green onions and tomatoes.200818416702
effects of dielectrophoresis on growth, viability and immuno-reactivity of listeria monocytogenes.abstract: dielectrophoresis (dep) has been regarded as a useful tool for manipulating biological cells prior to the detection of cells. since dep uses high ac electrical fields, it is important to examine whether these electrical fields in any way damage cells or affect their characteristics in subsequent analytical procedures. in this study, we investigated the effects of dep manipulation on the characteristics of listeria monocytogenes cells, including the immuno-reactivity to several listeria ...200818416836
new bioactive biomaterials based on quaternized chitosan.chitosan was chemically modified to produce quaternary ammonium salts in order to improve its antimicrobial activity and physicochemical properties. quaternization of n-alkyl chitosan derivatives was carried out using alkyl iodide to elaborate water-soluble cationic polyelectrolytes ( n, n, n-trimethylchitosan, tmc). tmc was characterized by (1)h nmr spectroscopy; the quaternization degree was determined from (1)h nmr spectra and by titration of iodide ion. the antibacterial activity of hydroxyp ...200818271546
development of a listeria monocytogenes based vaccine against prostate cancer.prostate specific antigen (psa) is a likely immunotherapeutic target antigen for prostate cancer, the second leading cause of cancer-related death in american men. previously, we demonstrated that attenuated strains of listeria monocytogenes (lm) can be used as effective vaccine vectors for delivery of tumor antigens causing regression of established tumors accompanied by strong immune responses toward these antigens in murine models of cancer. in the present study, we have developed and charact ...200818273616
listeria monocytogenes meningoencephalitis presenting with hydrocephalus and ventriculitis. 200818277040
influence of processing steps in cold-smoked salmon production on survival and growth of persistent and presumed non-persistent listeria monocytogenes.cold-smoked salmon is a ready-to-eat product in which listeria monocytogenes sometimes can grow to high numbers. the bacterium can colonize the processing environment and it is believed to survive or even grow during the processing steps. the purpose of the present study was to determine if the steps in the processing of cold-smoked salmon affect survival and subsequent growth of a persistent strain of l. monocytogenes to a lesser degree than presumed non-persistent strains. we used a sequence o ...200818279988
activity of daptomycin against listeria monocytogenes isolates from cerebrospinal fluid.we tested the activity of daptomycin against 76 listeria monocytogenes isolates from cerebrospinal fluid by broth dilution and etest methods. for the broth dilution method, the mic range was 1.0 to 8.0 and the mic at which 90% of the isolates tested were inhibited (mic(90)) was 4.0 mg/liter. for the etest method, the mic range was 1.0 to 4.0 and the mic(90) was 4.0 mg/liter. presently, daptomycin cannot be recommended for the treatment of l. monocytogenes meningitis.200818285470
cutting edge: il-27 is a potent inducer of il-10 but not foxp3 in murine t cells.the cytokine il-27 is important for restricting inflammation in response to a wide variety of immune challenges. in this study, we demonstrate that il-27 induces expression of the anti-inflammatory cytokine il-10 by cd4+ and cd8+ t cells. il-27 relied upon the th1 transcription factor stat1 to induce il-10+ifn-gamma+foxp3- th1 cells, which were recently shown to be key negative regulators during certain infections. il27ra-/- mice generated fewer il-10+ t cells during both listeria monocytogenes ...200818292493
constitutive expression of il-7 receptor alpha does not support increased expansion or prevent contraction of antigen-specific cd4 or cd8 t cells following listeria monocytogenes infection.expression of il-7ralpha (cd127) has been suggested as a major determinant in the survival of memory t cell precursors. we investigated whether constitutive expression of il-7ralpha on t cells increased expansion and/or decreased contraction of endogenous ag-specific cd4 and cd8 t cells following infection with listeria monocytogenes. the results indicate that constitutive expression of il-7ralpha alone was not enough to impart an expansion or survival advantage to cd8 t cells responding to infe ...200818292507
mutation in the fas pathway impairs cd8+ t cell memory.fas death pathway is important for lymphocyte homeostasis, but the role of fas pathway in t cell memory development is not clear. we show that whereas the expansion and contraction of cd8+ t cell response against listeria monocytogenes were similar for wild-type (wt) and fas ligand (fasl) mutant mice, the majority of memory cd8+ t cells in fasl mutant mice displayed an effector memory phenotype in the long-term in comparison with the mainly central memory phenotype displayed by memory cd8+ t cel ...200818292515
stimulation of enhanced cd8 t cell responses following immunization with a hyper-antigen secreting intracytosolic bacterial pathogen.the intracytosolic niche for replication of listeria monocytogenes (lm) facilitates delivery of bacteria-derived ags into the mhc class i pathway for subsequent stimulation of cd8 effector t cells. using lm strains that are equivalent for in vivo virulence yet express marked differences in the level of secretion of a protective target ag, we have evaluated how these specific differences in secretion levels influences the magnitude and effector function of ag-specific cd8 t cell responses followi ...200818292567
pseudomonas aeruginosa activates caspase 1 through ipaf.the innate immune system encodes cytosolic nod-like receptors (nlrs), several of which activate caspase 1 processing and il-1beta and il-18 secretion. macrophages respond to salmonella typhimurium infection by activating caspase 1 through the nlr ipaf. this activation is mediated by cytosolic flagellin through the activity of the virulence-associated type iii secretion system (t3ss). we demonstrate here that pseudomonas aeruginosa activates caspase 1 and induces il-1beta secretion in infected ma ...200818256184
multiple-locus variable-number tandem-repeat analysis as a tool for subtyping listeria monocytogenes strains.listeria monocytogenes, like many other food-borne bacteria, has certain strains that are commonly linked to outbreaks. due to the relatively low numbers of affected individuals, outbreaks of l. monocytogenes can be difficult to detect. the current technique of molecular subtyping in pulsenet laboratories to identify genetically similar strains is pulsed-field gel electrophoresis (pfge). while pfge is state-of-the-art, interlaboratory comparisons are difficult because the results are highly susc ...200818256218
prophages in listeria monocytogenes contain single-nucleotide polymorphisms that differentiate outbreak clones within epidemic clones.a fragment end ligation-mediated pcr strategy was used to analyze the asci pulsed-field gel electrophoresis patterns of listeria monocytogenes epidemic clone ii (ecii), which led to the identification of single-nucleotide polymorphisms (snps) in prophage regions that differentiated the two ecii outbreak clones. snps in prophages that differentiated the outbreak clones of eciii and -iv were also identified.200818256228
platelet-derived cd154 enables t-cell priming and protection against listeria monocytogenes challenge.collagen exposure in tissue activates platelets, initiates wound healing, and modulates adaptive immunity. in this report, data are presented to demonstrate a requirement for platelet-derived cd154 for both collagen-induced augmentation of t-cell immunity and induction of pro-tective immunity to listeria challenge. specifically, we demonstrate that ad5 encoding the membrane-bound form of ovalbumin (ad5-mova) delivered in collagen induces higher ovalbumin-specific cytotoxic t lymphocyte (ctl) act ...200818256321
a role for membrane-bound cd147 in nod2-mediated recognition of bacterial cytoinvasion.nod2 is an intracellular receptor for the bacterial cell wall component muramyl dipeptide. mutations in the leucine-rich repeat region of nod2, which lead to an impaired recognition of muramyl dipeptide, have been associated with chronic inflammatory diseases of barrier organs such as crohn disease, asthma and atopic eczema. in this study we identify cd147 (also known as bsg and emmprin), a membrane-bound regulator of cellular migration, differentiation and inflammatory processes, as a protein i ...200818256385
marked intra-strain variation in response of listeria monocytogenes dairy isolates to acid or salt stress and the effect of acid or salt adaptation on adherence to abiotic surfaces.during food processing, and particularly in cheese manufacturing processes, listeria monocytogenes may be exposed routinely to environments of low ph or high salt concentration. it has been suggested that these environmental conditions may contribute to bacterial adherence to abiotic surfaces and increased resistance to disinfection. in this study strains isolated from the environment of artisanal cheese-making dairies were used to investigate the behaviour of l. monocytogenes in response to aci ...200818258322
the cytosolic sensors nod1 and nod2 are critical for bacterial recognition and host defense after exposure to toll-like receptor ligands.the cytosolic sensors nod1 and nod2 and toll-like receptors (tlrs) activate defense signaling pathways in response to microbial stimuli. however, the role of nod1 and nod2 and their interplay with tlrs during systemic bacterial infection remains poorly understood. here, we report that macrophages or mice made insensitive to tlrs by previous exposure to microbial ligands remained responsive to nod1 and nod2 stimulation. furthermore, nod1- and nod2-mediated signaling and gene expression are enhanc ...200818261938
anti-listerial activity of a polymeric film coated with hybrid coatings doped with enterocin 416k1 for use as bioactive food packaging.in this study, enterocin 416k1, a bacteriocin produced by enterococcus casseliflavus im 416k1, was entrapped in an organic-inorganic hybrid coating applied to a ldpe (low-density polyethylene) film for its potential use in the active food packaging field. the antibacterial activity of the coated film was evaluated against listeria monocytogenes nctc 10888 by qualitative modified agar diffusion assay, quantitative determination in listeria saline solution suspension and direct contact with artifi ...200818262299
x-ray and neutron small-angle scattering analysis of the complex formed by the met receptor and the listeria monocytogenes invasion protein inlb.the listeria monocytogenes surface protein inlb binds to the extracellular domain of the human receptor tyrosine kinase met, the product of the c-met proto-oncogene. inlb binding activates the met receptor, leading to uptake of listeria into normally nonphagocytic host cells. the n-terminal half of inlb (inlb(321)) is sufficient for met binding and activation. the complex between this met-binding domain of inlb and various constructs of the met ectodomain was characterized by size exclusion chro ...200818262542
response of listeria monocytogenes to liquid smoke.to investigate the effect of liquid smoke on growth, survival, proteomic pattern and haemolytic potential of listeria monocytogenes.200818266702
stimulation of inducible nitric oxide synthase expression by beta interferon increases necrotic death of macrophages upon listeria monocytogenes infection.murine macrophage death upon infection with listeria monocytogenes was previously shown to be increased by beta interferon, produced by the infected cells. we saw that interferon-upregulated caspase activation or other interferon-inducible, death-associated proteins, including trail, protein kinase r, and p53, were not necessary for cell death. macrophage death was reduced when inducible nitric oxide synthase (inos) was inhibited during infection, and inos-deficient macrophages were less suscept ...200818268032
liposome-encapsulated antigens induce a protective ctl response against listeria monocytogenes independent of cd4+ t cell help.protection against intracellular pathogens is usually mediated by cytotoxic t lymphocytes (ctl). induction of a protective ctl response for vaccination purposes has proven difficult because of the limited access of protein antigens or attenuated pathogens to the mhc class i presentation pathway. we show here that ph-sensitive pe/chems liposomes can be used as a vehicle to efficiently deliver intact proteins for presentation by mhc class i. mice immunized with listerial proteins encapsulated in s ...200818433404
[listeria monocytogenes abscess of the brain].listeriosis commonly involves the central nervous system. meningoencephalitis and rhomboencephalitis are the most frequent manifestations. brain abscesses are rare.200818439933
response regulator degu of listeria monocytogenes controls temperature-responsive flagellar gene expression in its unphosphorylated state.we demonstrate that in listeria monocytogenes, temperature-responsive transcriptional control of flagellar genes does not rely on the phosphorylation of the conserved phosphorylation site (d55) in the receiver domain of response regulator degu. furthermore, proper control of degu-regulated genes involved in ethanol tolerance and virulence is independent of receiver phosphorylation.200818441066
tools for functional postgenomic analysis of listeria monocytogenes.we describe the development of genetic tools for regulated gene expression, the introduction of chromosomal mutations, and improved plasmid transfer by electroporation in the food-borne pathogen listeria monocytogenes. pimk, a kanamycin-resistant, site-specific, integrative listeriophage vector was constructed and then modified for overexpression (pimk2) or for isopropyl-beta-d-thiogalactopyranoside (iptg)-regulated expression (pimk3 and pimk4). the dynamic range of promoters was assessed by det ...200818441118
recombinant listeria monocytogenes expressing an immunodominant peptide fails to protect after intravaginal challenge with herpes simplex virus-2.recombinant listeria monocytogenes expressing a type-common herpes simplex virus (hsv) gb-peptide was shown previously to protect against footpad inoculation with hsv-1. we tested this construct for protection against vaginal challenge with hsv-2. primed mice demonstrated strong recall responses, had modest reductions in hsv-2 dna in vaginal mucosa, but were not protected from disease.200818443737
[investigation of listeria monocytogenes serotype o antibodies in maternal and cord sera and the evaluation of risk factors for listeriosis in pregnant women].listeria monocytogenes may lead to intrauterine infections which can be treated if diagnosed promptly. however, there is not a rapid routine screening test with high specificity and sensitivity for the diagnosis of listeriosis during pregnancy. we investigated the presence of different l. monocytogenes o antibodies for diagnosis of listeriosis in 275 paired maternal-cord sera using the agglutination test, and aimed to evaluate the correlation between poor pregnancy outcomes, level of l. monocyto ...200818444561
human listeria monocytogenes infections in europe--an opportunity for improved european surveillance.the 2006 community summary report from the european food safety authority (efsa) and the european centre for disease prevention and control (ecdc) was published recently with the latest trends and figures on the occurrence of zoonotic infections and agents, antimicrobial resistance and foodborne outbreaks in the then 25 european union (eu) member states and five non-eu countries. this article seeks to expand further upon reports of human listeriosis (listeria monocytogenes infections) and change ...200818445429
identification of drosophila mutants altering defense of and endurance to listeria monocytogenes infection.we extended the use of drosophila beyond being a model for signaling pathways required for pattern recognition immune signaling and show that the fly can be used to identify genes required for pathogenesis and host-pathogen interactions. we performed a forward genetic screen to identify drosophila mutations altering sensitivity to the intracellular pathogen listeria monocytogenes. we recovered 18 mutants with increased susceptibility to infection, none of which were previously shown to function ...200818245331
alkyl deoxy-arabino-hexopyranosides: synthesis, surface properties, and biological activities.octyl and dodecyl glycosides possessing 2-deoxy-arabino-hexopyranoside moieties belonging to the d- and l-series in their alpha- and beta-forms were synthesized by reaction of an acetyl protected glycal with octanol or dodecanol, catalyzed by triphenylphosphine hydrobromide, followed by deprotection. their surface properties were studied and discussed in terms of the adsorption and aggregation parameters, pc(20), cmc, and gamma(cmc). the antimicrobial activities were assessed using the paper dis ...200818249550
secreted enteric antimicrobial activity localises to the mucus surface layer.the intestinal mucosa is constantly exposed to a dense and highly dynamic microbial flora and challenged by a variety of enteropathogenic bacteria. antibacterial protection is provided in part by paneth cell-derived antibacterial peptides such as the alpha-defensins. the mechanism of peptide-mediated antibacterial control and its functional importance for gut homeostasis has recently been appreciated in patients with crohn's ileitis. in the present study, the spatial distribution of antimicrobia ...200818250125
antigen controls il-7r alpha expression levels on cd8 t cells during full activation or tolerance induction.the high-affinity chain of the il-7 receptor, il-7ralpha (cd127), is expressed by effector cd8 t cells that have the capacity to become memory cells. il-7ralpha expression is uniformly high on naive cd8 t cells, and the majority of these cells down-regulate expression upon antigenic challenge. at the peak of expansion, the fraction of effectors expressing high il-7ralpha varies depending on the response examined. the signals that a cd8 t cell receives during a response to ag that lead to altered ...200818250416
novel vaccination protocol with two live mucosal vectors elicits strong cell-mediated immunity in the vagina and protects against vaginal virus challenge.most hiv infections result from heterosexual transmission to women. because cellular immunity plays a key role in the control of the infection, we sought to strengthen cellular immune responses in vaginal tissue. we explored a novel prime-boost protocol that used two live mucosal agents that trigger different pathways of innate immunity and induce strong cellular immunity. adenovirus serotype 5 (ad5) has frequently been used as a boost for dna vaccines. in this study we used attenuated, recombin ...200818250460
hematopoietic response of rats exposed to the impact of an acute psychophysiological stressor on responsiveness to an in vivo challenge with listeria monocytogenes: modulation by chlorella vulgaris prophylactic treatment.in this study, we investigated the hematopoietic response of rats pretreated with cv and exposed to the impact of acute escapable, inescapable or psychogenical stress on responsiveness to an in vivo challenge with listeria monocytogenes. no consistent changes were observed after exposure to escapable footshock. conversely, the impact of uncontrollable stress (inescapable and psychogenical) was manifested by an early onset and increased severity and duration of myelossuppression produced by the i ...200818420376
microbial and sensory changes throughout the ripening of prato cheese made from milk with different levels of somatic cells.the objective of this research was to evaluate the effects of 2 levels of raw milk somatic cell count (scc) on the composition of prato cheese and on the microbiological and sensory changes of prato cheese throughout ripening. two groups of dairy cows were selected to obtain low-scc (<200,000 cells/ml) and high-scc (>700,000 cells/ml) milks, which were used to manufacture 2 vats of cheese. the pasteurized milk was evaluated according to the ph, total solids, fat, total protein, lactose, standard ...200818420604
magnetic resonance images in rhombencephalitis due to listeria monocytogenes mimicking wernicke encephalopathy. 200818421210
chitin hydrolysis by listeria spp., including l. monocytogenes.listeria spp., including the food-borne pathogen listeria monocytogenes, are ubiquitous microorganisms in the environment and thus are difficult to exclude from food processing plants. the factors that contribute to their multiplication and survival in nature are not well understood, but the ability to catabolize various carbohydrates is likely to be very important. one major source of carbon and nitrogen in nature is chitin, an insoluble linear beta-1,4-linked polymer of n-acetylglucosamine (gl ...200818424542
prevention of allograft tolerance by bacterial infection with listeria monocytogenes.exposure to certain viruses and parasites has been shown to prevent the induction of transplantation tolerance in mice via the generation of cross-reactive memory t cell responses or the induction of bystander activation. bacterial infections are common in the perioperative period of solid organ allograft recipients in the clinic, and correlations between bacterial infections and acute allograft rejection have been reported. however, whether bacterial infections at the time of transplantation ha ...200818424719
genome classification by gene distribution: an overlapping subspace clustering approach.genomes of lower organisms have been observed with a large amount of horizontal gene transfers, which cause difficulties in their evolutionary study. bacteriophage genomes are a typical example. one recent approach that addresses this problem is the unsupervised clustering of genomes based on gene order and genome position, which helps to reveal species relationships that may not be apparent from traditional phylogenetic methods.200818430250
infected ruptured popliteal artery aneurysm by listeria monocytogenes. a case report and review of the literatures.we describe a case of a voluminous infected aneurysm of the popliteal artery, with listeria monocytogenes (lm) associated with rupture, in a 72-year old man. after radical resection of the aneurysm a reconstruction was not necessary, because of the sufficient blood supply, due to the pre-existent good development of collateral circulation. the patient was discharged on the 12th postoperative day with primary healing of the wound and viable leg. adequate antibiotic treatment was continued for 4 w ...200818431345
[construction and characterization of a mutant strain of listeria monocytogenes with a deletion of acta and plcb].the virulence of listeria monocytogenes is directly related to its ability to spread from cell to cell without leaving the intracellular milieu. among the bacterial factors involved in cell-to-cell spread, actin-polymerizing protein acta is required for bacterial spread to adjacent cells, while the broad-range phospholipase c (pc-plc) contributes to bacterial escape from secondary vacuoles.200818479054
[bacteremia, brain abscess, and meningitis caused by listeria monocytogenes]. 200818479654
protease treatment affects both invasion ability and biofilm formation in listeria monocytogenes.listeria monocytogenes is a notably invasive bacterium associated with life-threatening food-borne disease in humans. several surface proteins have been shown to be essential in the adhesion of l. monocytogenes, and in the subsequent invasion of phagocytes. because the control of the invasion of host cells by listeria could potentially hinder its spread in the infected host, we have examined the effects of a protease treatment on the ability of l. monocytogenes to form biofilms and to invade tis ...200818479885
[primary listeria monocytogenes infection in a cirrhotic woman: report of one case].l. monocytogenes infections are infrequent. sepsis in pregnant women and newborns and central nervous system infections in the elderly are the most common clinical manifestations. we report a 61 years old woman with diabetes mellitus and a child b hepatic cirrhosis, admitted for persistent fever. blood cultures were positive for listeria monocytogenes. cerebrospinal fluid was normal and sterile. she was treated with ampicillin and amikacin with a good response. control blood cultures were negati ...200818483678
the generation of nisin variants with enhanced activity against specific gram-positive pathogens.nisin is the prototype of the lantibiotic group of antimicrobial peptides. it exhibits broad spectrum inhibition of gram-positive bacteria including important food pathogens and clinically relevant antibiotic-resistant bacteria. significantly, the gene-encoded nature of nisin means that it can be subjected to gene-based bioengineering to generate novel derivatives. here, we take advantage of this to generate the largest bank of randomly mutated nisin derivatives reported to date, with the ultima ...200818485077
acid sphingomyelinase is required for efficient phago-lysosomal fusion.the acid sphingomyelinase (asmase) localizes to the lumen of endosomes, phagosomes and lysosomes as well as to the outer leaflet of the plasma membrane and hydrolyses sphingomyelin to ceramide and phosphorylcholine. using the facultative intracellular bacterium listeria monocytogenes, we show that maturation of phagosomes into phagolysosomes is severely impaired in macrophages genetically deficient for asmase. unlike in wild-type macrophages, phagosomes containing l. monocytogenes in asmase(-/-) ...200818485117
synergistic effect between different milk-derived peptides and proteins.antimicrobial peptides derived from food proteins constitute a new field in the combined use of antimicrobial agents in food. the best examples of milk-derived peptides are those constituted by bovine lactoferricin [lactoferrin f(17-41)] (lfcin-b) and bovine alpha(s2)-casein f(183-207). the aim of this work was to study if the antimicrobial activity of a natural compound employed in food preservation, nisin, could be enhanced by combination with the aforementioned milk-derived peptides. furtherm ...200818487640
listeria monocytogenes and salmonella spp. in raw milk produced in brazil: occurrence and interference of indigenous microbiota in their isolation and development.this study aimed to verify the occurrence of listeria monocytogenes and salmonella spp. in raw milk produced in brazil. on account of the poor microbiological quality of this product, possible interference from the indigenous microbiota in these pathogens was also evaluated. two-hundred and ten raw milk samples were collected in four important milk-producing areas in brazil, tested for l. monocytogenes and salmonella spp. presence, and for enumeration of indicator microorganisms: mesophilic aero ...200818489543
pdl-1 blockade impedes t cell expansion and protective immunity primed by attenuated listeria monocytogenes.infection with attenuated listeria monocytogenes (lm) is a robust in vivo model for examining how ag-specific t cells are primed, and subsequent challenge with virulent lm allows for the protective effects of t cell priming to be quantified. herein, we investigated the role of programmed death ligand 1 (pdl-1) in t cell priming and immunity conferred after primary infection with lm deltaacta followed by virulent lm challenge. in striking contrast to the inhibitory role of pdl-1 on t cell immunit ...200818490756
multiple nod-like receptors activate caspase 1 during listeria monocytogenes infection.listeria monocytogenes escapes from the phagosome of macrophages and replicates within the cytosolic compartment. the macrophage responds to l. monocytogenes through detection pathways located on the cell surface (tlrs) and within the cytosol (nod-like receptors) to promote inflammatory processes aimed at clearing the pathogen. cytosolic l. monocytogenes activates caspase 1, resulting in post-translational processing of the cytokines il-1beta and il-18 as well as caspase 1-dependent cell death ( ...200818490757
listeriosis: a model for the fine balance between immunity and morbidity.listeriosis is a severe food-borne disease caused by listeria monocytogenes. it mostly affects immune-compromised individuals, pregnant women, and the elderly, and it is associated with huge economic losses, especially to the food industry. in the last decade, a sharp increase in listeriosis incidence was observed in several european countries. no suitable explanation was found for this increase, which occurred only in old patients and not in pregnant women.200818496469
lineage specific recombination and positive selection in coding and intragenic regions contributed to evolution of the main listeria monocytogenes virulence gene cluster.the major virulence cluster of listeria monocytogenes harbors six virulence genes that encode proteins critical for the intracellular life cycle of this human and animal pathogen. in this study, we determined the sequence (8709nt) of the virulence gene cluster (including the six main virulence genes) in 40 l. monocytogenes isolates from different source populations (human clinical cases, animal clinical cases, foods, and natural environments). an alignment of the full length cluster as well as i ...200818499533
glycerol metabolism and prfa activity in listeria monocytogenes.listeria monocytogenes is able to efficiently utilize glycerol as a carbon source. in a defined minimal medium, the growth rate (during balanced growth) in the presence of glycerol is similar to that in the presence of glucose or cellobiose. comparative transcriptome analyses of l. monocytogenes showed high-level transcriptional upregulation of the genes known to be involved in glycerol uptake and metabolism (glpfk and glpd) in the presence of glycerol (compared to that in the presence of glucos ...200818502850
coordinated regulation of cold-induced changes in fatty acids with cardiolipin and phosphatidylglycerol composition among phospholipid species for the food pathogen listeria monocytogenes.we present here the structural identification of four phospholipid (phl) classes in listeria monocytogenes, the fatty acid (fa) composition for each individual phl species, and a description of cold-induced fa changes. cardiolipin (48.5%) and phosphatidylglycerol (18.1%) are dominated by anteiso-fa, and the previously recognized branched fa chain shortening by cold was observed singularly in these phls. phosploaminolipid (19.9%) and phosphatidylinositol, (9.1%) are significantly different, conta ...200818502923
retail survey of brazilian milk and minas frescal cheese and a contaminated dairy plant to establish prevalence, relatedness, and sources of listeria monocytogenes isolates.a study was designed to recover listeria monocytogenes from pasteurized milk and minas frescal cheese (mfc) sampled at retail establishments (res) and to identify the contamination source(s) of these products in the corresponding dairy processing plant. fifty milk samples (9 brands) and 55 mfc samples (10 brands) were tested from res located in juiz de fora, minas gerais, brazil. all milk samples and 45 samples from 9 of 10 mfc brands tested negative for l. monocytogenes; however, "brand f" of m ...200818502929
listeria monocytogenes egd-e biofilms: no mushrooms but a network of knitted chains.listeria monocytogenes is a food pathogen that can attach on most of the surfaces encountered in the food industry. biofilms are three-dimensional microbial structures that facilitate the persistence of pathogens on surfaces, their resistance toward antimicrobials, and the final contamination of processed goods. so far, little is known about the structural dynamics of l. monocytogenes biofilm formation and its regulation. the aims of this study were, by combining genetics and time-lapse laser-sc ...200818502930
connatal listeriosis--a case report and the possibilities of microbiological diagnosis.the third most frequent agent of perinatal bacterial meningitis is listeria monocytogenes, in hungary, its occurrence is, however, uncommon. this raises the possibility of diagnostical mistakes. a connatal listeriosis case validated microbiologically referred to in this report calls attention to listeria, as a rare but relevant pathogen of neonatal infections. if clinical background suggests infection, the pathogenic role of l. monocytogenes should be taken into consideration. the etiological si ...200818507152
capping protein increases the rate of actin-based motility by promoting filament nucleation by the arp2/3 complex.capping protein (cp) is an integral component of arp2/3-nucleated actin networks that drive amoeboid motility. increasing the concentration of capping protein, which caps barbed ends of actin filaments and prevents elongation, increases the rate of actin-based motility in vivo and in vitro. we studied the synergy between cp and arp2/3 using an in vitro actin-based motility system reconstituted from purified proteins. we find that capping protein increases the rate of motility by promoting more f ...200818510928
a laboratory study of survival of selected microorganisms after heat treatment of biowaste used in biogas plants.the aim of the study was to assess the effect of pasteurisation, as set by the european regulation ec 1774/2002, on selected pathogens and indicator organisms. unpasteurised substrate (biowaste), including animal by-products from a full-scale biogas plant was heat treated under laboratory conditions at 70 degrees c and 55 degrees c for 30 min and 60 min. heat treatment at 55 degrees c for 60 min was not sufficient to achieve a hygienically acceptable product. heat treatment at 70 degrees c for 3 ...200818513960
listeria monocytogenes biofilm-associated protein (bapl) may contribute to surface attachment of l. monocytogenes but is absent from many field isolates.listeria monocytogenes is a food-borne pathogen capable of adhering to a range of surfaces utilized within the food industry, including stainless steel. the factors required for the attachment of this ubiquitous organism to abiotic surfaces are still relatively unknown. in silico analysis of the l. monocytogenes egd genome identified a putative cell wall-anchored protein (lmo0435 [bapl]), which had similarity to proteins involved in biofilm formation by staphylococci. an insertion mutation was c ...200818515491
validation of a commercial process for inactivation of escherichia coli o157:h7, salmonella typhimurium, and listeria monocytogenes on the surface of whole muscle beef jerky.we validated the lethality of three time and temperature regimens for commercial processing of whole muscle beef jerky. a total of ca. 8.9 log cfu per strip of multiple-strain cocktails of escherichia coli o157:h7, salmonella typhimurium, or listeria monocytogenes were separately applied onto the surface of beef strips that were treated as follows: (i) inoculated but not marinated or (ii) inoculated and then marinated. a total of three beef strips for each treatment in each of three trials were ...200818522024
a processing plant persistent strain of listeria monocytogenes crosses the fetoplacental barrier in a pregnant guinea pig model.the foodborne pathogen listeria monocytogenes can cause infection in immunocompromised humans and in the fetuses of pregnant women. we have demonstrated that one group of genetically similar l. monocytogenes strains (random amplified polymorphic dna [rapd] type 9) dominate and persist in several independent fish processing plants. the purpose of the present study was to determine the virulence potential of one rapd type 9 strain (la111), one human clinical strain (scott a), and one monkey clinic ...200818522041
dependency of caspase-1 activation induced in macrophages by listeria monocytogenes on cytolysin, listeriolysin o, after evasion from phagosome into the cytoplasm.listeriolysin o (llo), an hly-encoded cytolysin from listeria monocytogenes, plays an essential role in the entry of this pathogen into the macrophage cytoplasm and is also a key factor in inducing the production of ifn-gamma during the innate immune stage of infection. in this study, we examined the involvement of llo in macrophage production of the ifn-gamma-inducing cytokines il-12 and il-18. significant levels of il-12 and il-18 were produced by macrophages upon infection with wild-type l. m ...200818523249
molecular mimicry between neurons and an intracerebral pathogen induces a cd8 t cell-mediated autoimmune disease.to identify basic mechanisms of how infections may induce a neuron-specific autoimmune response, we generated mice expressing ova as neuronal autoantigen under control of the neuron-specific enolase promoter (nse-ova mice). intracerebral, but not systemic, infection with attenuated listeria monocytogenes-secreting ova induced an atactic-paretic neurological syndrome in nse-ova mice after bacterial clearance from the brain, whereas wild-type mice remained healthy. immunization with attenuated lis ...200818523310
method to detect only live bacteria during pcr amplification.ethidium monoazide (ema) is a dna cross-linking agent and eukaryotic topoisomerase ii poison. we previously reported that the treatment of ema with visible light irradiation (ema + light) directly cleaved chromosomal dna of escherichia coli (t. soejima, k. iida, t. qin, h. taniai, m. seki, a. takade, and s. yoshida, microbiol. immunol. 51:763-775, 2007). herein, we report that ema + light randomly cleaved chromosomal dna of heat-treated, but not live, listeria monocytogenes cells within 10 min o ...200818448692
in vivo hierarchy of individual t-cell epitope-specific helper t-cell subset against an intracellular bacterium.cellular immunity is indispensable for efficient protection against intracellular bacterial infection. cd4+ and cd8+ t cells specific for a variety of antigenic peptides derived from particular bacteria are induced after the infection. t cells recognizing different antigenic peptides have been speculated to have different functions in terms of the protective immunity. we here induced individual cd4+ t cells specific for each antigenic peptide derived from listeria monocytogenes independently wit ...200818450341
naive and innate memory phenotype cd4+ t cells have different requirements for active itk for their development.the tec family kinase itk regulates the development of conventional and innate cd8(+) t cells. however, little is known about the role of itk in the development of cd4(+) t cell lineages, although the role of itk in the t cell activation and function is well defined. we show in this study that itk null mice have increased percentage of cd62l(low)cd44(high) memory phenotype cd4(+) t cells compared with wild-type mice. these cells arise directly in the thymus, express high levels of transcripts fo ...200818453573
additive roles for mcp-1 and mcp-3 in ccr2-mediated recruitment of inflammatory monocytes during listeria monocytogenes infection.chemokine receptor-mediated recruitment of inflammatory cells is essential for innate immune defense against microbial infection. recruitment of ly6c(high) inflammatory monocytes from bone marrow to sites of microbial infection is dependent on ccr2, a chemokine receptor that responds to mcp-1 and mcp-3. although ccr2(-/-) mice are markedly more susceptible to listeria monocytogenes infection than are wild-type mice, mcp-1(-/-) mice have an intermediate phenotype, suggesting that other ccr2 ligan ...200818453605
characterization of virulence properties of listeria monocytogenes serotype 4b strains of different origins.in this study, the virulence heterogeneity of listeria monocytogenes serotype 4b strains of different origins was analysed on different levels. on one hand, the survival of l. monocytogenes strains in synthetic gastric fluid was studied. on the other hand, the pathogenic potential of strains with different inlb expression levels was analysed in an a/j mouse model for gastrointestinal listeriosis. differences in survival capacity in gastric fluid and in in vivo virulence potential were observed b ...200818454745
listeriosis in pregnancy. 200818455101
macrophages express multiple ligands for gammadelta tcrs.as only a handful of ligands have been identified, the general nature of the ligands recognized by gammadelta t cells remains unresolved. in this study, soluble multimerized gammadelta t cell receptors (smtcrs) representing the tcrs of two gammadelta t cell subsets common in the mouse were used to detect and track their own ligands. ligands for both subsets were found on resident peritoneal macrophages taken from untreated mice, and the expression of both was further induced by listeria monocyto ...200818455236
acupuncture-associated listeria monocytogenes arthritis in a patient with rheumatoid arthritis.septic arthritis is a rare complication of acupuncture. we present a patient with rheumatoid arthritis who developed septic arthritis of the right knee after consecutive weekly sessions of acupuncture therapy for 3 weeks. the infection was localized by musculoskeletal sonography and magnetic resonance imaging, with culture of the synovial fluid aspirated from the joint yielding listeria monocytogenes. the patient responded well to antibiotic treatment and regained joint mobility. a high index of ...200818455948
combined effect of freeze chilling and map on quality parameters of raw chicken fillets.the effect of short-term frozen storage prior to thawing on the quality of freeze-chilled chicken fillets was investigated, as was the effect of modified atmosphere packaging (map). four process treatments were used: (1) fresh chicken chilled at 4 degrees c without previous freezing, (2) freeze-chilled for 7 days and thawed at 4 degrees c, (3) chilled at 4 degrees c packaged under map (70% n(2)-30%co(2)), and (4) packaged under map, freeze-chilled for 7 days and thawed at 4 degrees c. microbiolo ...200818456112
identification of a non-pathogenic surrogate organism for chlorine dioxide (clo2) gas treatment.the identification of non-pathogenic surrogate microorganisms is beneficial for determining and validating the efficacy of antimicrobial treatments in food manufacturing environments. a surrogate organism was identified to aid in the decontamination process of fresh produce when treated with chlorine dioxide (clo(2)) gas. thirty-two known strains of pathogenic and non-pathogenic microorganisms and seven unknown microbial isolates from mushroom, tomatoes, and strawberries were evaluated. the prim ...200818456115
characteristics of an environmental strain, enterococcus faecalis cect7121, and its effects as additive on craft dry-fermented sausages.lactic acid bacteria are the most adequate microorganisms for natural preservation of food. in the present work, the strain of enterococcus faecalis cect7121 was employed in the manufacture of craft dry-fermented sausages and its performance as a biopreservative was analysed. this strain is devoid of the genes for haemolysin and gelatinase and does not produce biogenic amines. it is sensitive to almost all the antibiotics tested and opsonophagocytic assays showed that it is devoid of a capsule. ...200818456116
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