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mutational analysis of the sbo-alb locus of bacillus subtilis: identification of genes required for subtilosin production and immunity.the bacillus subtilis 168 derivative jh642 produces a bacteriocin, subtilosin, which possesses activity against listeria monocytogenes. inspection of the amino acid sequence of the presubtilosin polypeptide encoded by the gene sboa and sequence data from analysis of mature subtilosin indicate that the precursor subtilosin peptide undergoes several unique and unusual chemical modifications during its maturation process. the genes of the sbo-alb operon are believed to function in the synthesis and ...200010809709
antimicrobial and biological effects of ipemphos and amphos on bacterial and yeast strains.in this study, the antimicrobial effects of monophosphazenes such as sm ipemphos and amphos were examined on bacterial and yeast strains. in addition, the biological effects of these compounds were tested on the lipid level of saccharomyces cerevisiae and candida albicans cells. the sm has an antimicrobial effect on the bacterial and yeast strains within the range of 100 and 1500 microg. when the concentration was increased, the inhibition zone expanded on the growth media ( p < 0.01; p < 0.001) ...200010814970
interactions between listeria monocytogenes and host mammalian cells.bacterial pathogens have developed a variety of strategies to induce their own internalization into mammalian cells which are normally nonphagocytic. the gram-positive bacterium listeria monocytogenes enters into many cultured cell types using two bacterial surface proteins, inla (internalin) and inlb. in both cases, entry takes place after engagement of a receptor and induction of a series of signaling events.200010955961
application of a chromogenic medium and the pcr method for the rapid confirmation of l. monocytogenes in foodstuffs.detection of listeria monocytogenes in foodstuffs by conventional cultivation methods carried out according to en iso guidelines is rather time-consuming. therefore, two alternative methods were applied for rapid confirmation of l. monocytogenes in foodstuffs. inoculum from liquid selective broth was plated on palcam and oxford agar and on chromogenic agar medium rapid l. mono. suspect colonies from palcam were confirmed according to en iso standards and by the multiplex pcr method. in total, 99 ...200010958972
glycidol modulation of the immune responses in female b6c3f1 mice.the immunotoxic potential of glycidol was evaluated in female b6c3f1 mice using a battery of functional assays and three host resistance models. glycidol was administered to the animals by oral gavage as a solution in sterile distilled water daily for 14 days at doses of 25, 125 and 250 mg/kg. in tier i, we observed that glycidol exposure produced a dose-related decrease in splenocyte igm antibody-forming cell response to sheep red blood cells (srbc); the spleen natural killer (nk) cell activity ...200010959546
trimethoprim-sulfamethoxazole salvage for refractory listeriosis during maintenance chemotherapy for acute lymphoblastic leukemia.a 5-year-old boy with acute lymphoblastic leukemia (all) and intolerance to oral trimethoprim-sulfamethoxazole (tmp/smx) had listeria monocytogenes bacteremia and meningitis develop during maintenance chemotherapy. despite prompt administration of iv amoxicillin/gentamicin and microbiologic clearance of the bloodstream, the patient had no response to therapy after a course of 7 days. intravenous tmp/smx (10 mg/kg per day of tmp) was added to the antibiotic regimen after desensitization. fever an ...200010959905
[neurological complications of renal transplant].advances in surgical procedures and new immunosuppressor therapies have improved the outcome of renal grafts. however, these changes have been accompanied by infectious, neoplastic and neurologic complications. the purpose of this study was to determine the incidence of neurologic complications among 542 patients receiving a renal transplant (from living or cadaveric donors) at cemic between 1970 and 1996. neurologic complications occurred in 43 patients (8%) as follows: 8 meningitis (1.5%), 8 a ...200010962803
a role for alpha-and beta-catenins in bacterial uptake.interaction of internalin with e-cadherin promotes entry of listeria monocytogenes into human epithelial cells. this process requires actin cytoskeleton rearrangements. here we show, by using a series of stably transfected cell lines expressing e-cadherin variants, that the ectodomain of e-cadherin is sufficient for bacterial adherence and that the intracytoplasmic domain is required for entry. the critical cytoplasmic region was further mapped to the beta-catenin binding domain. because beta-ca ...200010963665
listeria monocytogenes in faeces from clinically healthy dairy cows in sweden.faecal samples from 102 clinically healthy dairy cows, representing 34 farms in the swedish province of uppsala, were analysed for the presence of listeria spp. using an enrichment procedure. listeria monocytogenes was isolated from six (6%) and l. innocua from 2 (2%) cows. from each of the 6 samples positive for l. monocytogenes, 5 isolates were further characterised by restriction enzyme analysis using the 3 enzymes apa i, sma i, and asc i, followed by pulsed-field gel electrophoresis. three o ...200010965567
acid tolerance in listeria monocytogenes influences invasiveness of enterocyte-like cells and macrophage-like cells.clinical and food listeria monocytogenes isolates, pre-exposed to mild acidic conditions, were able to readily develop acid tolerance, irrespective of their origin. we attempted to investigate the influence of acid tolerance mechanisms, either constitutive or induced, on the invasive behaviour of this facultative food-borne pathogen. entry efficiency and intracellular growth of acid-tolerant strains were evaluated in in vitro cell models capable to mimic in vivo target cells, such as enterocytes ...200010968945
the effect of culture growth phase on induction of the heat shock response in yersinia enterocolitica and listeria monocytogenes.the effect of culture growth phase on induction of the heat shock response in yersinia enterocolitica and listeria monocytogenes, was examined. exponential or stationary preconditioned cultures were heat shocked and survivor numbers estimated using selective and overlay/resuscitation recovery techniques. the results indicate that prior heat shock induced increased heat resistance in both micro-organisms to higher heat treatments. heat-shocked cells of each micro-organism were able to survive muc ...200010971751
combined action of s-carvone and mild heat treatment on listeria monocytogenes scott a.the combined action of the plant-derived volatile, s-carvone, and mild heat treatment on the food-borne pathogen, listeria monocytogenes, was evaluated. the viability of exponential phase cultures grown at 8 degrees c could be reduced by 1.3 log units after exposure to s-carvone (5 mmol l-1) for 30 min at 45 degrees c, while individual treatment with s-carvone or exposure to 45 degrees c for 30 min did not result in a loss in viability. other plant-derived volatiles, namely carvacrol, cinnamalde ...200010971762
a small outbreak of listeriosis potentially linked to the consumption of imitation crab meat.a small outbreak of listeriosis involving two previously healthy adults occurred in ontario. food samples obtained from the refrigerator of the patients included imitation crab meat, canned black olives, macaroni and vegetable salad, spaghetti sauce with meatballs, mayonnaise and water. all of the samples except the water contained listeria monocytogenes. the three most heavily contaminated samples were the imitation crab meat, the olives and the salad which contained 2.1 x 109, 1.1 x 107 and 1. ...200010972708
selective amplification of bacterial rna: use of a dna primer containing mismatched bases near its 3' terminus to reduce false-positive signals.a reverse transcription pcr (rt-pcr) method designed to reduce false-positive results due to the co-amplification of contaminating genomic dna is reported. feasibility of the method was evaluated using 16s rrna sequences specific to bacillus cereus. a dna oligonucleotide primer, consisting of 22-bases containing three consecutive mismatched bases near its 3' terminus (primer b16rt), was used for reverse transcription and in subsequent cdna amplification. specific rrna was reverse transcribed at ...200010972726
regulation of growth inhibition at high temperature, autolysis, transformation and adherence in streptococcus pneumoniae by clpc.the clpc atpase is a subfamily of hsp100/clp molecular chaperones-regulators of proteolysis. by screening a library of loss of function mutants for the ability to survive treatment with penicillin, we identified the gene clpc. the corresponding protein was identified as a clpc atpase, sharing strong peptide sequence identity with clpc of bacillus subtilis, listeria monocytogenes and lactococcus lactis. northern blot experiments showed that expression of clpc was induced in response to high tempe ...200010972795
etiologic spectrum and pattern of antimicrobial drug susceptibility in bacterial meningitis in sokoto, nigeria.etiologic agents of meningitis were prospectively investigated among patients admitted to usman danfodio university teaching hospital, sokoto. of 1097 cerebrospinal fluid (csf) samples submitted to the microbiology laboratory from various wards of the hospital, 289 (26%) were microscopically, culturally and/or serologically proven to be bacterial meningitis. the etiologic spectrum was as follows: neisseria meningitidis (61%), streptococcus pneumoniae (18%), haemophilus influenzae (10%), staphylo ...200010976835
quantifying translocation of listeria monocytogenes in rats by using urinary nitric oxide-derived metabolites.the urinary nitric oxide metabolites no(2)(-) and no(3)(-) (summed as no(x)) are a noninvasive, quantitative biomarker of translocation of salmonella from the intestinal lumen to systemic organs. listeria monocytogenes is a food-borne gram-positive pathogen that can also cross the intestinal epithelium. in this study, we tested the efficacy of urinary no(x) as a marker of listeria translocation. rats (eight per group) were orally infected with increasing doses of l. monocytogenes; control rats r ...200011097905
a cross-sectional study on the prevalence of listeria monocytogenes and salmonella in new york dairy herds.as part of our long-term objective of assessing risk for listeria monocytogenes and salmonella spp. in dairy herds, we carried out a cross-sectional study to determine the prevalence of the two organisms. the study population consisted of a sample of dairy herds enrolled in the quality milk promotion services at cornell during the period of april 1998 to march 1999. the sample was stratified by geographical region to assure representation. four hundred and four dairy farms were enrolled in the s ...200011104262
tnf-alpha blockade by a dimeric tnf type i receptor molecule selectively inhibits adaptive immune responses.tumor necrosis factor-alpha (tnf-alpha) is a mediator of severe inflammatory processes, including rheumatoid arthritis. suppression of tnf with a soluble type i or type ii receptor molecule (tnf-ri or tnf-rii) has the potential to decrease cytokine levels and modulate inflammatory diseases in humans. however, it has recently been reported that treatment of mice with a tnf-ri:fc immunoadhesin protein augmented gram positive infections and subsequent mortality. to determine if tnf-alpha blockade w ...200011105778
stimulatory action of pluchea quitoc extract on the hematopoietic response during murine listeriosis.the importance of both granulocytes and macrophages in the response to listeria monocytogenes infection make this infection a suitable choice to investigate the effects of pluchea quitoc on hematopoiesis. a significant depletion of bone marrow granulocyte-macrophage progenitor cells (cfu-gm) was observed at 48 and 72 h after intraperitoneal infection of mice with 1 x 10(4) l. monocytogenes. however, the treatment of infected animals with p. quitoc ethanolic extract (250, 500 or 1000 mg/kg) given ...200011105784
detection of listeria monocytogenes by polymerase chain reaction in intestinal mucosal biopsies from patients with inflammatory bowel disease and controls.components of the intestinal microflora are believed to play an important role in the pathogenesis of inflammatory bowel disease (ibd) in genetically susceptible hosts acting either as a non-specific antigenic stimulus or as a specific pathogen. listeria monocytogenes has been suggested as an organism with the potential to cause ibd. the objective of the present study was to investigate the prevalence of l. monocytogenes dna in intestinal biopsies from patients with ibd and from non-ibd controls ...200011106094
allergen immunotherapy: novel approaches in the management of allergic diseases and asthma.currently available pharmacotherapies for allergic diseases and asthma, which are serious public health problems, are aimed primarily at neutralizing effector molecules and inflammatory mediators such as histamine and leukotrienes or at inhibiting the function of inflammatory cells such as eosinophils and th2 lymphocytes. while this approach is effective in controlling symptoms, these therapies have a limited capacity to alter the natural course of allergic diseases and asthma, and discontinuati ...200011112358
pharmacological and antimicrobial studies on different tea-tree oils (melaleuca alternifolia, leptospermum scoparium or manuka and kunzea ericoides or kanuka), originating in australia and new zealand.three different species of myrtaceae growing in australia and new zealand are known as 'tea-tree': the australian tea tree (melaleuca alternifolia), the new zealand manuka (leptospermum scoparium) and kanuka (kunzea ericoides). all three essential oils are used by aromatherapists, although only melaleuca has been tested for toxicity, and its antimicrobial effects studied. the pharmacology and antimicrobial activity of the three 'tea-tree' oils was determined using guinea-pig ileum, skeletal musc ...200011114000
comparative investigations of listeria monocytogenes isolated from a turkey processing plant, turkey products, and from human cases of listeriosis in denmark.listeria monocytogenes was isolated from critical control points in a danish turkey processing plant, from turkey products and from cases of human listeriosis. during processing in the plant the prevalence of l. monocytogenes ranged from 25.9 to 41.4%. cleaning and disinfection decreased the prevalence to 6.4%. isolates of l. monocytogenes were characterized by pulsed-field gel electrophoresis (pfge) using restriction endonuclease apai. identical dna types were obtained from turkey products and ...200011117953
carbon tetrachloride is immunosuppressive and decreases host resistance to listeria monocytogenes and streptococcus pneumoniae in female b6c3f1 mice.carbon tetrachloride (ccl(4)) is an environmental contaminant that has been detected in ambient air, seawater, surface-water and snow. the immunotoxic potential of ccl(4) was evaluated in female b6c3f1 mice. the animals were administered with ccl(4) daily for 14 days at doses of 50, 100, 500 or 1000 mg/kg body weight by gavage with corn oil as a vehicle. exposure to ccl(4) resulted in an increase of liver weight but not the body weight and the weights of brain, spleen, lungs, thymus and kidneys. ...200011118673
the effect of thermal stress on campylobacter coli.enteropathogenic campylobacter jejuni, camp. coli and camp. lari are currently the most common cause of acute infectious diarrhoeal illness in the uk. many domestic animals, including pigs, act as natural reservoirs for these organisms and infection may occur through the ingestion of contaminated foodstuffs. the safety of locally produced porcine liver was assessed in relation to the heat susceptibility of campylobacter spp. present in eviscerated product.200011119166
immunotoxic effects of inorganic lead on host resistance of mice with different circling behavior preferences.we have observed differential immune responses in mice with different circling preferences, which are posited to reflect interindividual immune response differences influenced by brain laterality effects on neuroimmune circuits. in this study, we have investigated the influence of inorganic lead (pb) and/or listeria monocytogenes (lm) infection on the cytokine and corticosterone (cort) levels of mice grouped by lateralized behavior. pb increased the lm susceptibility of mice with both left (lc)- ...200011120598
early programming of t cell populations responding to bacterial infection.the duration of infection and the quantity of ag presented in vivo are commonly assumed to influence, if not determine, the magnitude of t cell responses. although the cessation of in vivo t cell expansion coincides with bacterial clearance in mice infected with listeria monocytogenes, closer analysis suggests that control of t cell expansion and contraction is more complex. in this report, we show that the magnitude and kinetics of ag-specific t cell responses are determined during the first da ...200011120806
ciboulot regulates actin assembly during drosophila brain metamorphosis.a dynamic actin cytoskeleton is essential for the remodeling of cell shape during development, but the specific roles of many actin partners remain unclear. here we characterize a novel actin binding protein, ciboulot (cib), which plays a major role in axonal growth during drosophila brain metamorphosis. loss of cib function leads to axonal growth defects in the central brain, while overexpression of the gene during development leads to overgrown projections. the cib protein displays strong sequ ...200011030623
gut feelings: enteropathogenic e. coli (epec) interactions with the host.enteropathogenic escherichia coli (epec) is a gram-negative bacterial pathogen that adheres to human intestinal epithelial cells, resulting in watery, persistent diarrhea. it subverts the host cell cytoskeleton, causing a rearrangement of cytoskeletal components into a characteristic pedestal structure underneath adherent bacteria. in contrast to other intracellular pathogens that affect the actin cytoskeleton from inside the host cytoplasm, epec remains extracellular and transmits signals throu ...200011031234
effect of selenium deficiency on the development of central nervous system lesions in murine listeriosis.the effect of selenium (se) deficiency, produced by feeding a se-deficient diet, on the development of central nervous system (cns) lesions was studied in mice infected with listeria monocytogenes, administered in drinking water for 1 or 7 days in a daily dose of 10(9)organisms, or for 7 days in a daily dose of 10(7). se-deficient mice differed from se-normal controls in developing cns lesions significantly more frequently. moreover, regardless of se status, mice receiving repeated doses of 10(9 ...200011032662
[listeria monocytogenes: a dangerous pathogen used as a vector for the new generation of vaccines].listeria monocytogenes (lm) has become a major pathogen of human foodborne illnesses eliciting meningitis, peritonitis, and abortions with a mortality rate of about 30%. during the course of the disease, lm infects a variety of tissues and cell types due to its capacity to induce its own phagocytosis even into non-phagocytic cells. for over 35 years lm continues to serve as a model to define general paradigms of immunology in this review we focus on the clinical characteristics of listeriosis, o ...200011033885
interaction of listeria monocytogenes with the intestinal epithelium.listeria monocytogenes is a food-borne pathogen that must cross the intestinal epithelial barrier to reach its target organs. we have investigated the importance of m cells in translocation using an experimental mouse model and a novel, recently described in vitro coculture system that mimics the follicle-associated epithelium (fae). our data demonstrate that l. monocytogenes does not require, nor specifically use, m cells of the fae to cross the gut. we also show that bacterial translocation is ...200011034299
bifidobacterium strains from resident infant human gastrointestinal microflora exert antimicrobial activity.the gastrointestinal microflora exerts a barrier effect against enteropathogens. the aim of this study was to examine if bifidobacteria, a major species of the human colonic microflora, participates in the barrier effect by developing antimicrobial activity against enterovirulent bacteria.200011034580
requirements for bone marrow-derived antigen-presenting cells in priming cytotoxic t cell responses to intracellular pathogens.bone marrow (bm)-derived antigen-presenting cells (apcs) are potent stimulators of t cell immune responses. we investigated the requirements for antigen presentation by these cells in priming cytotoxic t lymphocyte (ctl) responses to intracellular bacterial and viral pathogens. [parent-->f(1)] radiation bm chimeras were constructed using c57bl/6 donors and (c57bl/6 x balb/c)f(1) recipients. infection of chimeric mice with either listeria monocytogenes or vaccinia virus expressing the nucleoprote ...200011034603
partially tap-independent protection against listeria monocytogenes by h2-m3-restricted cd8+ t cells.effective protection against listeria monocytogenes requires ag-specific cd8(+) t cells. a substantial proportion of cd8(+) t cells activated during l. monocytogenes infection of c57bl/6 mice are restricted by the mhc class ib molecule h2-m3. in this study, an h2-m3-restricted cd8(+) t cell clone specific for a known h2-m3 epitope (fmigwii) was generated from l. monocytogenes-infected mice. the clone was cytotoxic, produced ifn-gamma, and could mediate strong protection against l. monocytogenes ...200011035099
altered membrane trafficking in activated bone marrow-derived macrophages.activation of macrophages with interferon-gamma (ifn-gamma) and lipopolysaccharide (lps) leads to increased intracellular resistance to microbes and increased major histocompatibility complex class ii-restricted antigen presentation, processes that both use the vacuolar compartment. despite the requirement of the macrophage vacuolar compartment for microbicidal activities and antigen processing, the rates of endocytosis and membrane trafficking in activated macrophages are not clearly defined. i ...200011037969
[listeria monocytogenes: a rare cause of pleurisy]. 200011039180
effect of enterocin crl35 on listeria monocytogenes cell membrane.the antimicrobial peptide enterocin crl35, a class ii bacteriocin, produces at high concentrations (8 microg ml(-1)) localized holes in the wall and cellular membrane of listeria monocytogenes, reflected in the efflux of macromolecules such as proteins and other ultraviolet-absorbing materials. at lower concentrations (0.5 microg ml(-1)), neither ultra structural changes nor macromolecules efflux were observed, however potassium and phosphate ions were released, dissipating the proton motive for ...200011040432
[a diagnostic medium for arcanobacterium haemolyticum and other bacterial species reacting with hemolytic synergism to the equi-factor of rhodococcus equi].colonies of arcanobacterium haemolyticum on common blood agar can be easily overlooked. therefore a diagnostic medium was developed, on which a. haemolyticum colonies produce a conspicuous zone of complete hemolysis. the medium under question is blood agar prepared from the columbia blood agar base and 5% washed sheep erythrocytes sensitised with equi factor (ef) of rhodococcus equi. optimally, 10 activity units (au) of ef per 1 ml were used. ef was titrated on a non-nutrient medium consisting o ...200011040494
infection and immunity in chronic lymphocytic leukemia.patients having chronic lymphocytic leukemia (cll) are at increased risk for infectious morbidity and mortality. the predisposition to infections in cll patients has many components, including both immunodeficiency related to the leukemia itself (humoral and cellular immune dysfunction) and the results of cumulative immunosuppression related to cll treatment. the risk of infectious complications increases with the duration of cll, reflecting the natural history of the disease and the cumulative ...200011040852
surface application of lysozyme, nisin, and edta to inhibit spoilage and pathogenic bacteria on ham and bologna.a study was conducted to determine if the effectiveness of an antimicrobial treatment for cooked ham and bologna would be increased or maintained when applied in a surface coating. cooked 10-g disks of ham and bologna sausage received one of three treatments: no coating (control), coating with 0.2 g of 7% (wt/vol) gelatin gel (gel-control), or coating with 0.2 g of 7% gelatin gel containing 25.5 g/liter of lysozyme-nisin (1:3) plus 25.5 g/liter of edta (gel-treated). the samples were then inocul ...200011041132
antimicrobial effect of rosemary extracts.a rosemary extract commercially exploited (oxy'less) as an antioxidant of lipids in foods was dissolved in ethanol (100 mg/ml), and the solution was tested against foodborne microorganisms. for gram-positive bacteria, the mic of the ethanolic solution was 1% for leuconostoc mesenteroides, 0.5% for listeria monocytogenes, 0.5% for staphylococcus aureus, 0.13% for streptococcus mutans, and 0.06% for bacillus cereus. it slowed the growth of penicillium roquefortii and botrytis cinerea. up to 1% of ...200011041135
comparison of the attachment of escherichia coli o157:h7, listeria monocytogenes, salmonella typhimurium, and pseudomonas fluorescens to lettuce leaves.attachment of escherichia coli o157:h7, listeria monocytogenes, salmonella typhimurium, and pseudomonas fluorescens on iceberg lettuce was evaluated by plate count and confocal scanning laser microscopy (cslm). attachment of each microorganism (approximately 10(8) cfu/ml) on the surface and the cut edge of lettuce leaves was determined. e. coli o157:h7 and l. monocytogenes attached preferentially to cut edges, while p. fluorescens attached preferentially to the intact surfaces. differences in at ...200011041147
listeria monocytogenes contamination pattern in pig slaughterhouses.ten low-capacity slaughterhouses were examined for listeria by collecting a total of 373 samples, of which 50, 250, and 73 were taken from carcasses, pluck sets, and the slaughterhouse environment, respectively. six slaughterhouses and 9% of all samples were positive for listeria monocytogenes. of the samples taken from pluck sets, 9% were positive for l. monocytogenes, the highest prevalence occurring in tongue and tonsil samples, at 14% and 12%, respectively. six of 50 (12%) carcasses were con ...200011041148
genome organization and the evolution of the virulence gene locus in listeria species.the chromosomal region of listeria monocytogenes harboring the gene cluster prfa-plca-hly-mpl-acta-plcb (virulence gene cluster; vgc) harbors virulence genes critical for the survival of the bacteria following infection. previous studies have implicated it as an ancestral pathogenicity island, derivatives of which are present in the species l. ivanovii and l. seeligeri, but absent in non-pathogenic species such as l. innocua. we cloned the corresponding region from l. innocua and l. welshimeri a ...200011045921
mhc class ib-restricted ctl provide protection against primary and secondary listeria monocytogenes infection.infection of b6 mice with the intracellular pathogen listeria monocytogenes (lm) results in the activation of cd8(+) t cells that respond to ag presented by both mhc class ia and class ib molecules. enzyme-linked immunospot analysis reveals that these ctl populations expand and contract at different times following a primary sublethal lm infection. between days 4 and 6 postinfection, class ib-restricted ctl exhibit a rapid proliferative response that is primarily h2-m3 restricted. the peak respo ...200011046052
kinetics of antibody production and clinical profiles of calves experimentally infected with listeria monocytogenes.clinical and serum antibody profiles were studied during oral listeria monocytogenes infection of calves. no clinical signs, except for pyrexia with mild diarrhoea and staggering gait, were observed in the infected calves. specific antibodies to listeriolysin o (llo) appeared as early as day 8 of an oral infection and peaked by days 16-32 of infection. antibodies to llo were observed to persist over the period of 126 days observed in the study. llo being a major virulence factor and capable of i ...200011048430
listeria and atypical presentations of listeria in the central nervous system.listeria monocytogenes infection of the central nervous system is often not recognized and treated appropriately in the crucial early stages of the disease. most consider patients with underlying disease or immunocompromised states to be at risk, although healthy individuals may present with a neurologic syndrome caused by l. monocytogenes. earlier suspicion and treatment remains our best means of reducing the morbidity and high mortality rate of this treatable disease. in addition to meningitis ...200011051300
an elastic analysis of listeria monocytogenes propulsion.the bacterium listeria monocytogenes uses the energy of the actin polymerization to propel itself through infected tissues. in steady state, it continuously adds new polymerized filaments to its surface, pushing on its tail, which is made from previously cross-linked actin filaments. in this paper we introduce an elastic model to describe how the addition of actin filaments to the tail results in the propulsive force on the bacterium. filament growth on the bacterial surface produces stresses th ...200011053107
identification and characterization of an atp binding cassette l-carnitine transporter in listeria monocytogenes.we identified an operon in listeria monocytogenes egd with high levels of sequence similarity to the operons encoding the opuc and opub compatible solute transporters from bacillus subtilis, which are members of the atp binding cassette (abc) substrate binding protein-dependent transporter superfamily. the operon, designated opuc, consists of four genes which are predicted to encode an atp binding protein (opuca), an extracellular substrate binding protein (opucc), and two membrane-associated pr ...200011055912
molecular epidemiological survey of listeria monocytogenes in seafoods and seafood-processing plants.to evaluate the role of seafoods in the epidemiology of human listeriosis and the role of the processing environment as a source of listeria monocytogenes in seafood products, 305 l. monocytogenes isolates were characterized by multilocus enzyme electrophoresis using 21 genetic loci and restriction enzyme analysis of total dna. forty-four isolates were recovered from patients in norway; 93 were isolated from seafoods, seafood-processing environments, and seawater from 55 different producers; and ...200011055923
growth limits of listeria monocytogenes as a function of temperature, ph, nacl, and lactic acid.models describing the limits of growth of pathogens under multiple constraints will aid management of the safety of foods which are sporadically contaminated with pathogens and for which subsequent growth of the pathogen would significantly increase the risk of food-borne illness. we modeled the effects of temperature, water activity, ph, and lactic acid levels on the growth of two strains of listeria monocytogenes in tryptone soya yeast extract broth. the results could be divided unambiguously ...200011055952
low sensitivity of listeria monocytogenes to quaternary ammonium compounds.ninety-seven epidemiologically unrelated strains of listeria monocytogenes were investigated for their sensitivities to quaternary ammonium compounds (benzalkonium chloride and cetrimide). the mics for seven serogroup 1/2 strains were high. three came from the environment and four came from food; none were isolated from human or animal samples. all 97 strains carried the mdrl gene, which encodes a multidrug efflux pump, and the orfa gene, a putative transcriptional repressor of mdrl. the absence ...200011055967
listeriosis in recipients of allogeneic bone marrow transplants from unrelated donors.two cases of listeriosis in patients submitted to matched unrelated donor bone marrow transplantation are reported. the patients developed listerial septicemia and listerial septicemia with meningitis and encephalitis 39 and 29 days after transplantation, respectively. including the present two cases, 19 listeria monocytogenes infections in related and unrelated donor allogeneic bone marrow transplant recipients have been reported to date. infection occurred earlier in unrelated donor transplant ...200011057507
development of th1-type immune responses requires the type i cytokine receptor tccr.on antigen challenge, t-helper cells differentiate into two functionally distinct subsets, th1 and th2, characterized by the different effector cytokines that they secrete. th1 cells produce interleukin (il)-2, interferon-gamma (ifn-gamma) and lymphotoxin-beta, which mediate pro-inflammatory functions critical for the development of cell-mediated immune responses, whereas th2 cells secrete cytokines such as il-4, il-5 and il-10 that enhance humoral immunity. this process of t-helper cell differe ...200011057672
a pest-like sequence in listeriolysin o essential for listeria monocytogenes pathogenicity.establishment and maintenance of an intracellular niche are critical to the success of an intracellular pathogen. here, the pore-forming protein listeriolysin o (llo), secreted by listeria monocytogenes, was shown to contain a pest-like sequence (p, pro; e, glu; s, ser; t, thr) that is essential for the virulence and intracellular compartmentalization of this pathogen. mutants lacking the pest-like sequence entered the host cytosol but subsequently permeabilized and killed the host cell. llo lac ...200011062133
effect of a matrix metalloproteinase inhibitor on host resistance against listeria monocytogenes infection.hydroxy acid-based matrix metalloproteinase (mmp) inhibitors have been shown to inhibit tumor infiltration and growth, endotoxin shock, and acute graft-versus-host disease. blockade of the release of soluble tumor necrosis factor-alpha (tnf-alpha) and cd95 ligand (cd95l; fasl) from cell-associated forms is reportedly involved in the mechanism of the drug effect. we investigated the effect of a mmp inhibitor, kb-r7785, on host resistance against listeria monocytogenes infection, in which tnf-alph ...200011064265
cutting edge: off cycling of tnf production by antigen-specific cd8+ t cells is antigen independent.although they are known for their capacity to kill infected cells, ag-specific cd8(+) t cells elaborate other effector mechanisms, including tnf and ifn-gamma, that contribute to defense against infection. ag-specific cd8(+) t cells rapidly turn on and turn off ifn-gamma production in direct response to ag contact, presumably to minimize the potential immunopathology that could result from inappropriate secretion of this inflammatory mediator. in this study, we show, using in vitro propagated an ...200011067887
[listeria infection risk]. 200011068613
cellular morphology of rough forms of listeria monocytogenes isolated from clinical and food samples.transmission electron microscopy (tem) studies revealed that rough cell-forms of l. monocytogenes (designated fr variants), isolated from clinical and food samples (and under conditions of sublethal heat stress), consist of either single or paired long-filaments. these fr variants markedly contrast in cell morphology from other previously described avirulent rough-mutants of l. monocytogenes that form long chains consisting of multiple cells of similar size (designated mcr variants). the identit ...200011068915
steps and fluctuations of listeria monocytogenes during actin-based motility.the actin-based motility of the bacterium, listeria monocytogenes, is a model system for understanding motile cell functions involving actin polymerization. although the biochemical and genetic aspects of listeria motility have been intensely studied, biophysical data are sparse. here we have used high-resolution laser tracking to follow the trailing ends of listeria moving in the lamellae of cos7 cells. we found that pauses during motility occur frequently and that episodes of step-like motion ...200011069185
oxymetholone modulates cell-mediated immunity in male b6c3f1 mice.oxymetholone is a synthetic androgen, structurally related to testosterone. it is currently used to treat anemias, but has also been abused as a performance enhancing anabolic steroid by the sport community. concern about its suspected immunomodulatory properties provided the incentive for a detailed investigation into its effects on the mammalian immune system. in this study, male b6c3f1 mice were treated for 14 d with oxymetholone (0, 50, 150, and 300 mg/kg) by gastric intubation, then evaluat ...200011071398
immunomodulation in dna damage and repair. 200011074359
[details of meningitis in the elderly].elderly patients being more at risk for infections than younger people, this study was aimed at defining the epidemiological and clinical features of meningitis in this population, with the objective of improving diagnosis and management.200011075393
reversable demential syndrome secondary to chronic central nervous system infection by listeria monocytogenes. 200011076191
microbiological hazard identification and exposure assessment of street food vending in johannesburg, south africa.one hundred and thirty-two samples of beef, chicken, salad and gravy were collected from two street vendors over eleven replicate surveys to assess microbiological safety and quality. for each food type samples were collected during preparation and holding. dish water was also collected and food preparation surfaces swabbed during preparation and display. standard methods were used to determine aerobic plate counts, enterobacteriaceae counts, coliform counts and spore counts. six hundred and sev ...200011078164
effects of combinations of lactoperoxidase system and nisin on the behaviour of listeria monocytogenes atcc 15313 in skim milk.individual or combined effects of nisin (100 or 200 iu/ml) and the lactoperoxidase system (lps) were analysed against 1 x 10(4) cfu/ml listeria monocytogenes atcc 15313 cells in skim milk, at 25 degrees c for 15 days. nisin induced an immediate bactericidal effect and lps a 48 h bacteriostatic phase which in both cases was followed by re-growth of l. monocytogenes. lps and nisin added together at t0 showed a synergistic and lasting bactericidal effect which after 8 days and until 15 days resulte ...200011078167
efficacy of electrolyzed oxidizing (eo) and chemically modified water on different types of foodborne pathogens.this study was undertaken to evaluate the efficacy of electrolyzed oxidizing (eo) and chemically modified water with properties similar to the eo water for inactivation of different types of foodborne pathogens (escherichia coli o157:h7, listeria monocytogenes and bacillus cereus). a five-strain cocktail of each microorganism was exposed to deionized water (control), eo water and chemically modified water. to evaluate the effect of individual properties (ph, oxidation-reduction potential (orp) a ...200011078171
stimulation of starter culture for further reduction of foodborne pathogens during salami fermentation.this study was conducted to determine if stimulated meat starter culture (msc; pediococcus acidilactici) would further control escherichia coli o157:h7, listeria monocytogenes, and staphylococcus aureus during salami fermentation. manganese ion (0.005% of mnso4) was used as a stimulator for the growth and acid production of msc. after 24-h salami fermentation, nonstimulated msc and stimulated msc reduced e. coli o157:h7 levels by 1.3 and 2.3 log10 units, respectively. nonstimulated msc reduced l ...200011079689
combined effect of bacteriocins on the survival of various listeria species in broth and meat system.the antilisterial efficiency of three bacteriocins from lactic acid bacteria, lactocin 705 (produced by l. casei crl705, 17000 au/ml), enterocin crl35 (produced by e. faecium crl35, 17000 au/ml), and nisin (2000 iu/ml), was tested in broth, individually and in combination against listeria monocytogenes and listeria innocua. both listeria species showed an initial decrease in viable counts followed by the regrowth of the survivors after 1 h in the presence of each bacteriocin. a greater antiliste ...200011080390
the rpon gene of enterococcus faecalis directs sensitivity to subclass iia bacteriocins.the final sigma 54 factor has been previously described to be involved in listeria monocytogenes sensitivity to mesentericin y105, a subclass iia bacteriocin. here, we identified the rpon gene, encoding final sigma 54, of enterococcus faecalis jh2-2 and showed that its interruption leads to e. faecalis resistance to different subclass iia bacteriocins. moreover, this rpon mutant remained sensitive to nisin, a class i bacteriocin, suggesting that final sigma 54 is especially involved in sensitivi ...200011080395
alternative strategies for becoming an insider: lessons from the bacterial world. 200011081622
inib-dependent internalization of listeria is mediated by the met receptor tyrosine kinase.the listeria monocytogenes surface protein inlb promotes bacterial entry into mammalian cells. here, we identify a cellular surface receptor required for inlb-mediated entry. treatment of mammalian cells with inlb protein or infection with l. monocytogenes induces rapid tyrosine phosphorylation of met, a receptor tyrosine kinase (rtk) for which the only known ligand is hepatocyte growth factor (hgf). like hgf, inlb binds to the extracellular domain of met and induces "scattering" of epithelial c ...200011081636
regulation of antigen-specific cd8+ t cell homeostasis by perforin and interferon-gamma.t cell memory depends on factors that regulate expansion and death of these cells after antigenic stimulation. mice deficient in perforin and interferon-gamma (ifn-gamma) exhibited increased expansion, altered immunodominance, and decreased death of antigen-specific cd8+ t cells after infection with an attenuated strain of listeria monocytogenes, which was cleared from these mice. expansion of cd8+ t cells was controlled by perforin, whereas ifn-gamma regulated immunodominance and the death phas ...200011082062
clpc atpase is required for cell adhesion and invasion of listeria monocytogenes.we studied the role of two members of the 100-kda heat shock protein family, the clpc and clpe atpases, in cell adhesion and invasion of the intracellular pathogen listeria monocytogenes. during the early phase of infection, a clpc mutant failed to disseminate to hepatocytes in the livers of infected mice whereas the invasive capacity of a clpe mutant remained unchanged. this was confirmed by a confocal microscopy study on infected cultured hepatocyte and epithelial cell lines, showing a strong ...200011083831
oppa of listeria monocytogenes, an oligopeptide-binding protein required for bacterial growth at low temperature and involved in intracellular survival.we identified a new oligopeptide permease operon in the pathogen listeria monocytogenes. this opp operon consists of five genes (oppa, oppb, oppc, oppd, and oppf) and displays the same genetic organization as those of several bacterial species. the first gene of this operon, oppa, encodes a 62-kda protein sharing 33% identity with oppa of bacillus subtilis and is expressed predominantly during exponential growth. the function of oppa was studied by constructing an oppa deletion mutant. the pheno ...200011083832
depletion of a gamma delta t cell subset can increase host resistance to a bacterial infection.gammadelta t lymphocytes have been shown to regulate immune responses in diverse experimental systems. because distinct gammadelta t cell subsets, as defined by the usage of certain tcr v genes, preferentially respond in various diseases and disease models, we have hypothesized that the various gammadelta t cell subsets carry out different functions. to test this, we compared one particular gammadelta t cell subset, the vgamma1(+) subset, which represents a major gammadelta t cell type in the ly ...200011086087
the impact of the quality of silage on animal health and food safety: a review.this paper reviews the microbiological aspects of forage preserved by ensilage. the main principles of preservation by ensilage are a rapid achievement of a low ph by lactic acid fermentation and the maintenance of anaerobic conditions. the silage microflora consists of beneficial micro-organisms, i.e. the lactic acid bacteria responsible for the silage fermentation process, and a number of harmful micro-organisms that are involved in anaerobic or aerobic spoilage processes. micro-organisms that ...200011087133
role of sigma(b) in adaptation of listeria monocytogenes to growth at low temperature.the activity of sigma(b) in listeria monocytogenes is stimulated by high osmolarity and is necessary for efficient uptake of osmoprotectants. here we demonstrate that, during cold shock, sigma(b) contributes to adaptation in a growth phase-dependent manner and is necessary for efficient accumulation of betaine and carnitine as cryoprotectants.200011092874
human dendritic cells infected by listeria monocytogenes: induction of maturation, requirements for phagolysosomal escape and antigen presentation capacity.an important feature of microbial infections is the ability of the microorganisms to interfere with and modulate the induction of host immune reactions. however, little is known about the effects of broad host range pathogens such as listeria monocytogenes on similar cell types in different hosts. here we examine the effects of the human and animal pathogen l. monocytogenes on human dendritic cells (dc) since this type of cells is essential for the initiation of immune responses. listeria are ph ...200011093163
effect of acid-adaptation on listeria monocytogenes survival and translocation in a murine intragastric infection model.acid tolerance response mechanisms can greatly influence listeria monocytogenes survival in low ph foods. in the present paper, the effect of acid-adaptation together with control of gastric ph level on l. monocytogenes survival and translocation was analyzed after intragastric inoculation in the balb/c mouse model. our results showed that acid-adaptation led to an increase in resistance to the first barrier constituted by the low gastric ph and that inoculation at alkaline ph had a synergistic ...200011094295
the main cold shock protein of listeria monocytogenes belongs to the family of ferritin-like proteins.the transfer of the food-borne pathogen listeria monocytogenes from 30 to 5 degrees c was characterized by the sharp induction of a low molecular mass protein. this major cold shock protein has an isoelectric point at ph 5.1 and a molecular mass of about 18 kda, as observed on two-dimensional gel electrophoresis (2-de) pattern. its n-terminal sequence, obtained from the 2-de spot, shared a complete sequence identity with a listeria innocua non-heme iron-binding ferritin. the purification of thes ...200010981685
persistent listeria monocytogenes strains show enhanced adherence to food contact surface after short contact times.adherence of 3 persistent and 14 nonpersistent listeria monocytogenes strains to stainless steel surfaces after short and long contact times was investigated. l. monocytogenes strains were obtained from poultry plants and an ice cream plant throughout several years. adherence tests were performed in tryptic soy broth at 25 degrees c for 1, 2, and 72 h. test surfaces were rinsed after the contact time, and attached cells were stained with acridine orange and enumerated with an epifluorescence mic ...200010983793
incidence and seasonal variation of listeria species in bulk tank goat's milk.four hundred and fifty raw goat's milk samples obtained from the bulk tanks of 39 goat farms were analyzed for listeria spp. over a 1-year period. modified versions of the u.s. department of agriculture food safety and inspection service (usda-fsis) and food and drug administration (fda) protocols were used for recovery of listeria. overall, 35 (7.8%) samples yielded listeria spp. with listeria monocytogenes identified in 17 of the 35 (3.8%) listeria-positive samples. listeria innocua was detect ...200010983794
use of oleic acid to reduce the population of the bacterial flora of poultry skin.the effect of oleic acid on native bacterial flora of poultry skin was examined. skin from commercial broiler carcasses was washed once or twice in solutions of 0, 2, 4, 6, 8, or 10% (wt/vol) oleic acid and rinsed in peptone water. aerobic bacteria, enterobacteriaceae, campylobacter, and enterococci in the rinsates were enumerated. significantly fewer aerobic bacteria, enterobacteriaceae, campylobacter, and enterococci were recovered from rinsates of skin washed in oleic acid than from control s ...200010983807
myosin light chain kinase plays an essential role in s. flexneri dissemination.shigella flexneri, the causitive agent of bacillary dysentery, has been shown to disseminate in colonic epithelial cells via protrusions that extend from infected cells and are endocytosed by adjacent cells. this phenomenon occurs in the region of the eukaryotic cell's adherens junctions and is inhibited by pharmacological reagents or host cell mutations that completely disrupt the junctional complex. in this study, inhibitors of the myosin light chain kinase (mlck) were shown to dramatically de ...200010984429
[epidemiology of human listeria infections in france].human listeriosis is a relatively rare but serious disease with case fatality rates between 20 and 30%. the majority of patients who have listeriosis present with meningitis or septicaemia. listeriosis during pregnancy can lead to a congenital infection, neonatal sepsis and meningitis or foetal death. the main mode of transmission is through contaminated foods. the infection usually occurs sporadically but small outbreaks and even large epidemics have occurred in a large number of industrialised ...200010989536
[prevention of listeria infections].listeriosis is a rare but very serious foodborne disease. the non-contamination of food products is the best prevention of listeriosis. in spite of notable efforts to improve the microbiologic quality of food products through surveillance and control of food contaminations, the prevention has still to be based upon the information of consumers. this information can take different forms. when a food product is found to be contaminated with listeria monocytogenes, if the withdrawal of this product ...200010989539
dual epitope recognition by the vasp evh1 domain modulates polyproline ligand specificity and binding affinity.the ena-vasp family of proteins act as molecular adaptors linking the cytoskeletal system to signal transduction pathways. their n-terminal evh1 domains use groups of exposed aromatic residues to specifically recognize 'fpppp' motifs found in the mammalian zyxin and vinculin proteins, and acta protein of the intracellular bacterium listeria monocytogenes. here, evidence is provided that the affinities of these evh1-peptide interactions are strongly dependent on the recognition of residues flanki ...200010990454
activation of host phospholipases c and d in macrophages after infection with listeria monocytogenes.infection of the j774 murine macrophage-derived cell line with listeria monocytogenes results in several elevations of intracellular calcium during the first 15 min of infection. these appear to result from the actions of secreted bacterial proteins, including phosphatidylinositol-specific phospholipase c (pi-plc), a broad-range phospholipase c, and listeriolysin o (llo) (s. j. wadsworth and h. goldfine, infect. immun. 67:1770-1778, 1999). we have measured hydrolysis of host pi and the activatio ...200010992479
presence of bacterial 16s ribosomal rna gene segments in human intestinal lymph follicles.there is currently no information regarding microbial agents inside the intestinal lymph follicles.200010994621
vidas enzyme-linked immunoflourescent assay for detection of listeria in foods: collaborative study.the vidas lis method and the traditional culture methods for detection of listeria species in food were evaluated in a multilaboratory comparative study. the 6 foods tested were either naturally contaminated or inoculated with 3 different concentrations of listeria. results for each food and each contamination level with the vidas lis method were as good as or better than those obtained with the traditional culture method. of 1558 samples tested, 935 were positive: 839 by the vidas method and 80 ...200010995115
insertional knock-out of protein translocation systems common for yersinia enterocolitica and listeria monocytogenes.to carry out efficient insertional mutagenesis in listeria monocytogenes and to facilitate the characterisation of disrupted genes, a novel derivative of plasmid pacyc 184 was constructed, pliv vira3, carrying a fragment from the vira region of the of y. enterocolitica plasmid pyve 0:9. after transformation of this plasmid into l. monocytogenes it was possible to select for its integration into the host dna at 42 degrees c. insertional mutants of l. monocytogenes obtained by using pliv vector co ...200010997489
comparative genomics of the late gene cluster from lactobacillus phages.three prophage sequences were identified in the lactobacillus johnsoni strain ncc533. prophage lj965 predicted a gene map very similar to those of pac-site streptococcus thermophilus phages over its dna packaging and head and tail morphogenesis modules. sequence similarity linked the putative dna packaging and head morphogenesis genes at the protein level. prophage lj965/s. thermophilus phage sfi11/lactococcus lactis phage tp901-1 on one hand and lactobacillus delbrueckii phage ll-h/lactobacillu ...200010998330
delivery of protein antigens and dna by virulence-attenuated strains of salmonella typhimurium and listeria monocytogenes.two different plasmid-vector systems were developed which allow the efficient production and presentation of protein antigens in antigen-presenting cells (apc) by means of virulence-attenuated bacteria. the first antigen-delivery system is based on the secretion machinery of the escherichia coli hemolysin (hlya-type i secretion system), which transports proteins, possessing the specific hlya secretion signal (hlya(s)) at the c-terminus, across both membranes of gram-negative bacteria. this syste ...200011000455
cloning, sequence analysis, and expression of lactobacillus casei phage pl-1 lysis genes.the genes encoding the host cell wall-lytic proteins were searched in the genome dna of phage pl-1 active against lactobacillus casei atcc 27092 by comparing the amino acid sequences with those of others using a computer software of the ddbj data base. the gene regions found were cloned into e. coli by inserting pcr-amplified dna fragments into the ecori site of puc 19, and the nucleotide sequences were determined. one of the orfs (hol) consisted of 270 bp encoding 90 amino acids. the hol produc ...200011003466
identification in listeria monocytogenes of meca, a homologue of the bacillus subtilis competence regulatory protein.we identified in listeria monocytogenes a gene encoding a protein homologous to meca, a regulatory protein acting with clpc and comk in the competence pathway of bacillus subtilis. in l. monocytogenes, meca is involved, along with clpc and clpp, in the downregulation of a 64-kda secreted protein. in b. subtilis, the meca protein of l. monocytogenes behaves as a regulatory protein, controlling the transcription of comk and comg. complete or disrupted comk homologues were also found in l. monocyto ...200011004200
bacterial penetration across the blood-brain barrier during the development of neonatal meningitis.bacterial pathogens may breach the blood-brain barrier (bbb) and invade the central nervous system through paracellular and/or transcellular mechanisms. transcellular penetration, e.g., transcytosis across the bbb has been demonstrated for escherichia coli k1, group b streptococcus, listeria monocytogenes, citrobacter freundii and streptococcus pneumonia strains. genes contributing to invasion of brain microvascular endothelial cells include e. coli k1 genes ompa, ibea, ibeb, and yijp. understan ...200011008113
interleukin-18 (il-18) and infectious diseases, with special emphasis on diseases induced by intracellular pathogens.interleukin-18 (il-18) is a novel cytokine mainly produced by activated macrophages. il-18 was originally called interferon-gamma inducing factor, due to its action in inducing ifn-gamma secretion from th1 cells, nk cells and nkt cells. it has been reported that il-18 may play important roles in various diseases including cancer and infectious diseases. this review deals with the roles of il-18 in infectious diseases, with special emphasis on il-18 in infectious diseases caused by intracellular ...200011008115
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