Publications

TitleAbstractYear(sorted descending)
Filter
PMID
Filter
ultrastructural characteristics of some bacteria after treatment with lubrol w.specific ultrastructural changes occurred mainly in the cell wall and cytoplasmic membrane of listeria monocytogenes, salmonella typhimurium, pseudomonas pseudomallei and pseudomonas aeruginosa bacteria when treated with 0.5% and 1% lubrol w1 by means of transmission and scanning electron microscopy.19947700161
models of innate immunity and opportunistic infection in the scid mouse. 19947701112
isolation and characterization of two bacteriocins produced by enterococcus faecium strains inhibitory to listeria monocytogenes.a total of 4000 bacterial strains were isolated from milk, cheese and from different samples taken on the farm (silage, faeces) and screened for their antimicrobial activity against listeria monocytogenes. only eight of the almost 4000 strains exhibited inhibitory activity in the cell-free supernatant fluid. two different enterococcus strains (rzs c5 and rzs c13) were chosen for further study. plasmid profile analysis of both revealed that rzs c5 contained a 4 kb plasmid while rzs c13 contained ...19947703015
utilization of cheddar cheese containing nisin as an antimicrobial agent in other foods.cheddar cheese made with nisin-producing lactococci contained between 400 and 1200 iu of nisin per gram of cheese. cultures used were lactococcus lactis ssp. cremoris js102, a nisin-producing transconjugant developed in the laboratories of dr. l.l. mckay and lactococcus lactis ssp. lactis ncdo 1404 obtained from the national collection of food bacteria, reading, england. pasteurized process cheese spreads with 53% and 60% moisture and 0, 301 and 387 iu nisin/g were manufactured and inoculated wi ...19947703016
growth suppression of listeria monocytogenes in a meat product.bologna-type sausages were manufactured using standard industry processes and four different formulations: (a) standard commercial formulation (control), (b) with 2% sodium lactate, (c) with 2% lactate and 0.25% glucono-delta-lactone (gdl), (d) with 2% lactate and 0.5% gdl. the sliced sausages were inoculated with a mixture of l. monocytogenes serotype 1 and 4 (approximately 100 cfu/g). the samples were vacuum-packaged and stored at 5 degrees c and 10 degrees c for 35 days. rapid growth of l. mo ...19947703021
application of a statistical bootstrapping technique to calculate growth rate variance for modelling psychrotrophic pathogen growth.the inherent variability or 'variance' of growth rate measurements is critical to the development of accurate predictive models in food microbiology. a large number of measurements are typically needed to estimate variance. to make these measurements requires a significant investment of time and effort. if a single growth rate determination is based on a series of independent measurements, then a statistical bootstrapping technique can be used to simulate multiple growth rate measurements from a ...19947703023
bacteriocins of leuconostocs isolated from meat.several bacteriocin-producing leuconostoc strains have been isolated from meat and identified as leuconostoc gelidum ual 187, leuconostoc paramesenteroides-la7a, leuconostoc carnosum-ta11a and leuconostoc carnosum-la54a. all strains produce bacteriocins that are active against listeria monocytogenes and other lactic acid bacteria of concern in meat spoilage. all of the bacteriocins studied are heat stable in acidic environments and are inactivated by a range of proteolytic enzymes but not by cat ...19947703031
growth modelling of listeria monocytogenes and yersinia enterocolitica in food model systems and dairy products.the growth potential of listeria monocytogenes, measured with a gaschromatographic method, was evaluated in model systems simulating dairy products in which nacl concentration, ph and lipid concentration ranged from values corresponding to matured hard cheeses to some light cheeses and other dairy products. the growth data from the model systems, calculated on the basis of the polynomial models obtained, were compared with values observed for dairy products. growth parameters of yersinia enteroc ...19947703032
insertions within iap gene of listeria monocytogenes generated by plasmid pliv are not lethal.to carry out efficient insertional mutagenesis in listeria monocytogenes 1040s and to facilitate the characterisation of disrupted genes, three novel derivatives of plasmid pacyc 184 were constructed, p-liv 1, pliv-2 and pliv-3. the technique is simple and rapid and can be applied to most genes, even those that are essential. the method is unique and particularly effective by the use of a temperature-sensitive pe 194 replicon to facilitate the insertion of the gene. after transformation of the p ...19947530893
nadph diaphorase staining suggests a transient and localized contribution of nitric oxide to host defence against an intracellular pathogen in situ.nitric oxide (no) is formed constitutively in neurons by the constitutive enzyme no synthase (cnos) and acts as a neurotransmitter. it has already been shown that cnos-containing neurons are identical to neurons staining for nadph diaphorase and vice versa. effector cells of the immune response produce high no levels after appropriate stimulation and this no is formed by inducible no synthase (inos). the no produced by macrophages is considered an important effector molecule of antimicrobial hos ...19947532430
efficiency of mhc class i antigen processing: a quantitative analysis.listeria monocytogenes is an intracellular pathogen that secretes proteins into host cell cytosol. one such protein, the murein hydrolase p60, is processed by the host cell into the nonamer peptide p60 217-225 and presented to cytotoxic t lymphocytes by the h-2kd mhc class i molecule. using strains of l. monocytogenes that secrete different amounts of p60, we show that the rate of p60 217-225 production is proportional to the quantity of intracellular antigen. the appearance of p60 217-225 is co ...19947534616
inability of interferon-gamma and aminoguanidine to alter cryptosporidium parvum infection in mice with severe combined immunodeficiency.severe combined immunodeficiency (scid) mice have been useful in identifying specific host defense systems responsible for containing and eradicating cryptosporidium parvum infection. adult scid mice were given c. parvum oocysts and treated weekly with monoclonal antimurine interferon-gamma (anti-ifn-gamma). anti-ifn-gamma-treated mice had more cryptosporidia seen in the intestines and had more severe morphologic changes associated with disease than control mice. to assess the mechanism of this ...19947515109
inhibitory effects of enrichment media on the accuprobe test for listeria monocytogenes.during an evaluation of the accuprobe kit for the detection of listeria monocytogenes, some of the enrichment media used were found to interfere with the test. microscopic examination during the lysis step of the test revealed that media containing high salt greatly reduced or prevented cell lysis. this prevented the probe from binding to the cellular rna, resulting in false-negative results.19947517132
evidence that alpha-fetoprotein suppresses the immunological function in transgenic mice.we examined the in vivo immunosuppressive effect of alpha-fetoprotein (afp) by infection experiments with listeria monocytogenes, a facultative intracellular pathogen, using transgenic mice that express and produce human afp. the transgenic mice showed diminished ability to eliminate bacteria in the early stage of infection. in addition, the transgenic mice had significantly reduced production of ifn-gamma in their livers and sera and tnf in their spleens. these data indicate that afp suppresses ...19947517667
mice lacking granulocyte colony-stimulating factor have chronic neutropenia, granulocyte and macrophage progenitor cell deficiency, and impaired neutrophil mobilization.mice lacking granulocyte colony-stimulating factor (g-csf) were generated by targeted disruption of the g-csf gene in embryonal stem cells. g-csf-deficient mice (genotype g-csf-/-) are viable, fertile, and superficially healthy, but have a chronic neutropenia. peripheral blood neutrophil levels were 20% to 30% of wild-type mice (genotype g-csf+/+) and mice heterozygous for the null mutation had intermediate neutrophil levels, suggesting a gene-dosage effect. in the marrow of g-csf-/- mice, granu ...19947521686
chicken antibodies to rabbit muscle actin with a restricted repertoire of f-actin recognition.this report describes a polyclonal antibody against actin with unexpected and unusual properties. the antibody was raised in chicken immunized with a complex of dnase i and rabbit skeletal muscle actin, and purified from egg yolk by affinity chromatography. in western blots, it reacted with alpha, beta and gamma isoforms of actin. in immunofluorescence and dot blot assays, however, it recognized selectively actin filaments in myofibrils, microvilli of brush border-type epithelium and the "comet ...19947521836
enhanced sensitivity in pcr detection of listeria monocytogenes in soft cheese through use of an aqueous two-phase system as a sample preparation method.a sample treatment method based on an aqueous two-phase system containing polyethylene glycol and dextran was developed for enhancing sensitivity in the detection of listeria monocytogenes in soft cheese with pcr. the results suggest that the improved detection sensitivity following partitioning of the cheese homogenate in an aqueous two-phase system may be due to partitioning of the pcr inhibitors to the polyethylene glycol phase.19947524445
tnf-alpha and ifn-gamma stimulate a macrophage precursor cell line to kill listeria monocytogenes in a nitric oxide-independent manner.macrophages are important effector cells for resolving infection with the facultative intracellular bacterium listeria monocytogenes. however, not all macrophages have the ability to kill this organism. certain factors, such as cytokines, are apparently required for induction of macrophage bactericidal activity. in vivo studies have shown that both tnf-alpha and ifn-gamma play important roles in resistance against listeria. yet whether they act directly on macrophages has been difficult to deter ...19947525724
listeria monocytogenes peritonitis in cirrhotic patients. value of ascitic fluid gram stain and a review of literature.listeria monocytogenes has been increasingly implicated in spontaneous bacterial peritonitis in patients with cirrhosis. this bacterium can be mistaken for diphtheroids and gram-positive cocci if special attention is not paid to the motility pattern and specific biochemical tests. although the sensitivity of ascitic fluid gram stain is low, we describe a case in which the gram stain of the ascites fluid was positive. this issue is now pertinent given recent recommendations of third-generation ce ...19947506643
direct sequence identification and kinetic analysis of an mhc class i-restricted listeria monocytogenes ctl epitope.murine infection with the intracellular bacterium listeria monocytogenes elicits mhc class i-restricted ctl with specificity for multiple bacterial peptides. the variety and relative abundance of self-peptides bound by mhc molecules make identification of pathogen-derived peptides difficult. in this report, the sequence of a pathogen-derived ctl epitope is determined by direct analysis of peptides extracted from mhc class i molecules. the epitope, p60 217-225, is presented to l. monocytogenes-sp ...19947506732
antilisterial immunity includes specificity to listeriolysin o (llo) and non-llo-derived determinants.subclinical infection of balb/c mice with virulent listeria monocytogenes leads to the generation of listeria-specific t-cell populations required for the expression of protective immunity. the l. monocytogenes-produced hemolysin listeriolysin o (llo) is a virulence factor which appears to be crucial for the induction of protective antilisterial immunity. analysis of the specificity of antilisterial cytotoxic cells from listeria-immune balb/c donors has shown a dominant response to an epitope co ...19947509313
nitric oxide produced during murine listeriosis is protective.nitric oxide (no) has been shown to be important for intracellular microbiostasis in vitro. to determine the role of no in immune function in vivo, groups of c57bl/6 mice were given a sublethal intravenous inoculum of listeria monocytogenes egd, and their urine was monitored daily for nitrate, the mammalian end product of no metabolism. urinary nitrate levels peaked at 5 to 10 times the basal level on days 5 to 6, when spleen and liver listeria counts declined most steeply, and decreased thereaf ...19947509315
transcriptional enhancement of the listeria monocytogenes pcr and simple immunoenzymatic assay of the product using anti-rna:dna antibodies.a method was developed to enhance the sensitivity of a listeria monocytogenes pcr detection system by in vitro transcription of amplicons incorporating bacteriophage t7 rna polymerase promoter sequences in one of the priming oligonucleotides. the resulting transcript can be detected by hybridization with a dna probe immobilized in the wells of a microtiter plate, followed by immunoenzymatic assay of the rna-dna hybrids with an anti-rna-dna hybrid antibody. this highly sensitive method was reacti ...19947509587
pcr primers and probes for the 16s rrna gene of most species of pathogenic bacteria, including bacteria found in cerebrospinal fluid.a set of broad-range pcr primers for the 16s rrna gene in bacteria were tested, along with three series of oligonucleotide probes to detect the pcr product. the first series of probes is broad in range and consists of a universal bacterial probe, a gram-positive probe, a bacteroides-flavobacterium probe, and two probes for other gram-negative species. the second series was designed to detect pcr products from seven major bacterial species or groups frequently causing meningitis: neisseria mening ...19947512093
unusual infections following allogeneic bone marrow transplantation for chronic lymphocytic leukemia.unusually severe infections phenomena were observed in three patients with chronic lymphocytic leukemia (cll) who had undergone allogeneic bone marrow transplantation (bmt) from matched sibling donors. the first developed three episodes of cytomegaloviremia requiring anti-viral therapy; the third episode accompanied by cytomegalovirus hepatitis which required prolonged therapy with foscarnet. another had listeria monocytogenes meningitis which was difficult to eradicate and required prolonged ma ...19947889013
functional overlap in the src gene family: inactivation of hck and fgr impairs natural immunity.we have generated mice with targeted disruptions of the src-like genes hck and fgr to assess the role of these kinases in myeloid cell development and function. hematopoiesis appears to proceed normally in both hck-l- and fgr-l- animals, and in hck-l(-)-fgr-l- double homozygotes, but phagocytosis is impaired in hck-l- macrophages. macrophages cultured from doubly homozygous, hck-l(-)-fgr-l- animals retain many other normal functional properties, suggesting that the deficiency of these kinases is ...19948125254
sinusitis in human immunodeficiency virus infection: typical and atypical organisms.the majority of patients with human immunodeficiency virus (hiv) infection will develop acute sinusitis. this may be a single episode, or may be the beginning of a long course of recurrent sinusitis, of which the etiology is not yet well understood. a retrospective study of cultures from antral washings was conducted to determine the organisms that were more commonly isolated in patients with hiv infection and sinusitis. forty-seven organisms were isolated from the sinus cultures of 41 hiv-posit ...19947897779
neutralization of il-12 decreases resistance to listeria in scid and c.b-17 mice. reversal by ifn-gamma.interleukin-12 (il-12) is necessary for the production of ifn-gamma by nk cells during the generation of innate immunity and by t cells for the development of the th1 response during specific cell-mediated immunity. here we demonstrate that the endogenous production of il-12 is critical to the survival of both immunocompromised scid mice and normal c.b-17 control mice during a primary infection with listeria monocytogenes. when il-12 is neutralized in vivo, both strains of mice die at a normally ...19947907107
impaired immune and acute-phase responses in interleukin-6-deficient mice.interleukin-6 (il-6) is a multifunctional cytokine that regulates various aspects of the immune response, acute-phase reaction and haematopoiesis (for reviews see refs 1, 2). in vitro, leukaemia inhibitory factor, oncostatin m, ciliary neurotrophic factor and interleukin-11 display overlapping activities with il-6. this functional redundancy may be explained by the interactions of specific binding receptors with a common signal-transducing receptor (gp130) (for reviews see refs 3, 4). to elucida ...19948127368
the type i macrophage scavenger receptor binds to gram-positive bacteria and recognizes lipoteichoic acid.macrophage scavenger receptors exhibit unusually broad binding specificity for polyanionic ligands and have been implicated in atherosclerosis and various host defense functions. using a radiolabeled, secreted form of the type i bovine macrophage scavenger receptor in an in vitro binding assay, we have found that this receptor binds to intact gram-positive bacteria, including streptococcus pyogenes, streptococcus agalactiae, staphylococcus aureus, enterococcus hirae, and listeria monocytogenes. ...19948127896
in vitro activity of rufloxacin against listeria monocytogenes, legionella pneumophila, and chlamydia trachomatis.the in vitro activity of a new fluoroquinolone, rufloxacin, was determined against both clinical isolates and standard strains of legionella pneumophila, chlamydia trachomatis, and listeria monocytogenes and compared to that of ciprofloxacin, ofloxacin, and erythromycin. among the antibacterials tested erythromycin was the most active. rufloxacin inhibited the growth of l. pneumophila at concentrations in the range of 0.06-0.25 mg/l, that of c. trachomatis at concentrations in the range of 2-4, ...19948131632
[species-specific detection of listeria monocytogenes by directed dna amplification].a highly sensitive species-specific test system which allows detection listeria monocytogenes in animal tissues is elaborated using the principle of a polymerase chain reaction. the potentialities of its application were studied in the conditions of experimental infection of animals. it is shown that while the procedure of detection is relatively simple and fast, the test system is as sensitive and specific as traditional microbiological methods.19948133847
purification and cloning of sakacin 674, a bacteriocin from lactobacillus sake lb674.sakacin 674, a bacteriocin produced by lactobacillus sake lb764 and which inhibits the growth of listeria monocytogenes, was purified to homogeneity by ammonium sulphate precipitation and sequential ion exchange, hydrophobic interaction and reversed phase chromatography. the complete amino acid sequence of sakacin 674 was determined by edman degradation. the bacteriocin consisted of 43 amino acid residues and had a calculated molecular mass of 4436.6 da, which is in good agreement with the molec ...19948138128
an in-vitro meat model for the immediate bactericidal effect of lactic acid decontamination on meat surfaces.an in-vitro model of the lactic acid decontamination (lad) of meat is described. as lad is a disinfection rather than a preservation process the model is based on the inactivation kinetics of bacteria in a suspension of pork skin. the model takes account of interfering factors present in nature, such as microbial interactions, leaching of organic material from the meat surfaces and buffering activity.19948144404
antimicrobial activity of shredded carrot extracts on food-borne bacteria and yeast.purified ethanolic extracts of peeled and shredded carrots showed an antimicrobial effect against a range of food-borne micro-organisms. the minimum inhibitory concentration, expressed as mg ml-1 dried carrot material used for the extraction were: leuconostoc mesenteroides, 27; listeria monocytogenes, > 27 < 55; staphylococcus aureus, > 27 < 55; pseudomonas fluorescens, > 55 < 110; candida lambica, > 55 < 110; escherichia coli, > 110 < 220. the antimicrobial activity was not linked to phenolic c ...19948144415
septic shock and adult respiratory distress syndrome due to listeria monocytogenes. 19948163769
co-trimoxazole for the treatment of listeriosis and its successful use in a patients with aids. 19948163829
photochemical inactivation of pathogenic bacteria in human platelet concentrates.platelet concentrates (pc) may be infrequently contaminated with low levels of bacteria that can cause septicemia and death in patients receiving transfusion therapy. we evaluated the efficacy of a photochemical decontamination (pcd) technique using 8-methoxypsoralen (8-mop) and long wavelength uv light (uva) to inactivate bacteria in standard therapeutic pc. twelve phylogenetically distinct pathogenic bacteria, 5 gram-positive and 7 gram-negative organisms, were seeded into pc to a final challe ...19948167348
cellular interactions of murine immune cells exposed to live mycobacterium intracellulare, its whole lipid extract, and its serovar-specific glycopeptidolipid.in this study we examined some of the immunological responses to mycobacterium intracellulare and its lipid components. our results indicate that infection with m. intracellulare can increase the expression of adhesion molecules, icam-1 and lfa-1, only at the site of injection (peritoneum). there was no change in the expression of these adhesion molecules in the lymphoid organs (thymus and spleen). significant increases in the adhesion molecules were observed in the spleen cells incubated with t ...19948168139
mice with an acquired immunodeficiency (maids) develop a persistent infection after injection with listeria monocytogenes.mice with a retrovirus-induced immunodeficiency were challenged with listeria monocytogenes and resistance to this facultative intracellular bacterium was analyzed. early innate immunity was unaltered or enhanced. although immunodeficient mice had reduced bacterial titers after these reached their peak on day 3, infection with l. monocytogenes generally resulted in a low-grade persistent infection and occasionally there was a delayed resolution of bacterial infection. endogenous cytokines are im ...19948168147
protein phosphorylation in murine peritoneal macrophages induced by infection with salmonella species.infection of peritoneal macrophages from c3h/hen and c3h/hej mice with salmonella typhimurium or s. enteritidis induced extensive phosphorylation in a set of proteins with molecular masses of 85, 72, 35, 30, and 23 kda, which were different from those induced by bacterial lipopolysaccharide. the phosphorylated proteins of 35, 30, and 23 kda (pp35, pp30, and pp23, respectively) originated from the infecting bacteria, because living bacteria could induce these phosphorylated proteins themselves, a ...19948168916
antigen-specific t-cell responses during primary and secondary listeria monocytogenes infection.although murine listeriosis is a widely used experimental model for the analysis of cell-mediated immunity, there is little information about individual t-cell antigens of listeria monocytogenes which are recognized during primary and secondary infection. to study the antigen responses of l. monocytogenes-reactive t cells, somatic and secreted listerial proteins were separated by two-dimensional gel electrophoresis and subsequently divided into 480 liquid fractions. antigen-specific t cells isol ...19948168953
fate of listeria monocytogenes during the souring of ergo, a traditional ethiopian fermented milk.the growth potential of three strains of listeria monocytogenes during the natural souring of raw milk into ergo was studied to determine the effect of souring and container smoking on their inactivation. all three strains of l. monocytogenes grew well in sterile milk in unsmoked containers, reaching counts > 10(7) cfu/ml within 24 h at ambient temperature. smoking of containers decreased the growth rate of the strains for 24 h but had varying effects on the strains. for all test strains, the co ...19948169276
listeriosis--a review of eighty-four cases.to review the epidemiology, risk factors for acquisition, clinical features and outcomes of listeria monocytogenes infection in sydney.19948170424
psychrotrophs in dairy products: their effects and their control.health concerns and technological effects of psychrotrophic bacteria in dairy products are reviewed, as well as methods to control their presence and development. the various gram-negative and gram-positive psychrotrophic species are listed and, with respect to pathogenic psychrotrophs, emphasis is given on listeria monocytogenes, yersinia enterocolitica, and bacillus cereus. the influence of psychrotrophic bacteria on the quality of raw milk, pasteurized and uht milks, butter, ice cream, cheese ...19948142043
effect of ifn-gamma and endogenous tnf on the histopathological changes in the liver of listeria monocytogenes-infected mice.during primary infection of mice with listeria monocytogenes, the bacteria proliferate extensively in the liver resulting in the development of inflammatory lesions in this organ. in the present study, the effect of interferon-gamma (ifn-gamma) on the development of these lesions, and the involvement of endogenous tumour necrosis factor-alpha (tnf-alpha) in the ifn-gamma-induced effects were evaluated. during an infection of naive mice with l. monocytogenes, two types of inflammatory lesions in ...19948157268
inhibition of allograft rejection by anti-t-cell receptor-alpha beta monoclonal antibodies preserving resistance to bacterial infection.anti-cd3 monoclonal antibody (mab) has been administered in clinical organ transplantation to reverse acute allograft rejection; however, severe immunodeficiency can result from such mab treatment and cause an increased incidence of opportunistic infections. therefore, new model systems are required in order to establish better methods for suppressing allograft rejection while preserving resistance to opportunistic infections. in this study, we compared the effects of the in vivo administration ...19948157269
listeria monocytogenes and severe newborn respiratory failure supported with extracorporeal membrane oxygenation.to determine the efficacy of extracorporeal membrane oxygenation (ecmo) in newborn infants with early-onset listeria monocytogenes infection, necrotizing pneumonia, and severe respiratory failure.19948180643
cloning and sequencing of sakp encoding sakacin p, the bacteriocin produced by lactobacillus sake lth 673.sakacin p is a heat-stable, unmodified peptide bacteriocin produced by lactobacillus sake lth 673. the strain was isolated from fermented dry sausages and is well adapted to this habitat. the bacteriocin inhibits the growth of the opportunistic food pathogens enterococcus faecalis and listeria monocytogenes and therefore, it may improve the hygienic status of fermented food, i.e. meat products. oligonucleotide probes were designed from the n-terminal amino acid sequence of sakacin p and used to ...19948180701
listeria meningitis presenting as enteritis in a previously healthy infant: a case report.a previously healthy 1-year-old infant was admitted with pyrexia and mild gastro-intestinal symptoms. a blood culture, taken on admission, showed growth of listeria monocytogenes (serotype 4b) on the 3rd day, at which time a lumbar puncture revealed a listeric meningitis. despite the delay of antibiotic treatment, the infant never showed any neurological symptoms. she recuperated without any residual effects.19948181501
listeria monocytogenes capd peritonitis: failure of vancomycin therapy. 19948182032
role of macrophages and alpha beta t lymphocytes in early interleukin 10 production during listeria monocytogenes infection.immunity to intracellular bacteria including listeria monocytogenes is determined by th1 cells and cd8 t cells which produce interferon-gamma. here we show that high levels of il-10 are released by splenocytes from mice infected with l. monocytogenes. il-10 was detected on day 1 after infection, peaked on day 4, and subsequently declined. cell separation studies and experiments with rag-1-deficient mice, which do not possess mature b cells or t cells, revealed that the macrophage is the major ce ...19948186197
an h2-t mhc class ib molecule presents listeria monocytogenes-derived antigen to immune cd8+ cytotoxic t cells.mouse spleen t cells can adoptively transfer immunity to listeria monocytogenes; this activity was markedly enhanced by stimulation with con a in vitro before transfer. the enhanced and prolonged protection against l. monocytogenes in vivo was correlated with enhanced lysis in vitro of target cells infected with strains of l. monocytogenes that produce listeriolysin o (llo). one of the targets of such cytotoxic cells from balb/c (h2d) mice was a peptide that corresponded to amino acids 91 to 99 ...19948189053
role of il-6 in activation of t cells for acquired cellular resistance to listeria monocytogenes.we have previously shown that il-6 is a major cytokine in the serum of mice infected with the intracellular bacterium listeria monocytogenes, and that injection of ril-6 before, but not after, infection promotes the recovery of mice from listeriosis. here we demonstrate that il-6 is required in the early stages of infection, in that injection of anti-il-6 ab 24 or 4 h before infection, but not 24 h after, led to a massive increase in bacterial numbers 4 or more days after infection. on the other ...19948189056
sendai virus pneumonia: evidence for the early recruitment of gamma delta t cells during the disease course.we previously reported that gamma delta t cells appeared and could play a protective role early in infections with intracellular bacteria such as listeria monocytogenes, mycobacterium bovis bcg, and salmonella choleraesuis. to extend these findings to virus infection, we examined the developmental sequence of gamma delta t cells in bronchoalveolar lavage during the course of sendai virus infection in c57bl/6 mice. to produce a natural but nonlethal infection course as far as possible, we used a ...19948189536
arrest of listeria movement in host cells by a bacterial acta analogue: implications for actin-based motility.upon entering the host cell's cytoplasm, the pathogen listeria monocytogenes can subvert the normal contractile system of the host cell; subsequent assembly of polar actin-filament structures is likely to provide the force for rapid intracellular bacterial movement and its cell-to-cell spread. we have now investigated the functional consequences of microinjecting listeria-infected ptk2 cells with a synthetic peptide, cfefpppptde. this peptide represents one of four related oligoproline stretches ...19948197202
the bovine placentome in bacterial and mycotic abortions.placentomes were extracted from the uteri of 22 aborted cows and examined to detect the cause of abortion; fetuses or fetal abomasal contents from 15 of the cows were also examined. firm diagnoses of pasteurella haemolytica, actinomyces pyogenes, listeria monocytogenes, bacillus licheniformis, aspergillus fumigatus or mortierella wolfii abortion were made in 11 cases. the histopathological lesions showed some correlation with the identity of the bacterium isolated; the lesions of mycotic abortio ...19948197693
determination of the presence of listeria monocytogenes in milk and dairy products: idf collaborative study.a collaborative study was conducted on the recovery of viable listeria monocytogenes from milk and dairy products (camembert cheese, limburger cheese, skim milk powder, and ice cream). test portions were homogenized with listeria-selective liquid enrichment medium and cultured at 30 degrees c for 48 h. the enrichment culture was then subcultured onto a solid isolation medium at 37 degrees c for 48 h. suspected listeria colonies were identified by appropriate conventional morphological, physiolog ...19948199474
effects of uv-b on the resistance against infectious diseases.it is known that ultraviolet-b light (uv-b) affects human health. in addition to deleterious effects on the skin and the eyes, such as erythema, photoageing, keratitis and cataract, uv-b is also able to impair the resistance against skin-associated tumours and infections. our data implicate that uv-b can impair the resistance against certain non-skin-associated infections in rats, such as listeria monocytogenes, trichinella spiralis and ratcytomegalovirus (rcmv). rats, infected with t. spiralis, ...19948202953
inhibition of intracellular growth of listeria monocytogenes by antibiotics.we studied the activities of 15 antibiotics on the intracellular growth of listeria monocytogenes in a hela cell line. after 24 h of contact with the infected cells, the antibiotics most effective against the intracellular growth of the 10 strains tested were amoxicillin, temafloxacin, and sparfloxacin, which nevertheless failed to totally eliminate the intracellular bacteria. rifampin and co-trimoxazole had variable effects, depending on the isolates studied. the most active combinations were a ...19948203836
an immunotoxicity assessment of food flavouring ingredients.a rapid screening protocol incorporating key elements of the us national toxicology program's immunotoxicity tier testing strategy was used to evaluate the effects of 35 commonly used food flavouring ingredients on humoral and cell-mediated immune responses. the test compounds were administered intragastrically on a daily basis for 5 days at three dose levels to female cd-1 or b6c3f1 mice, 6-8 wk old. a host resistance assay (listeria monocytogenes bacterial challenge) was conducted to assess ce ...19948206439
interstitial lung macrophages interact with dendritic cells to present antigenic peptides derived from particulate antigens to t cells.when the protective structural and functional barriers of the lung are breached, immune responses must be generated in order to contain invading micro-organisms. this requires the presence of accessory cells capable of phagocytosing and presenting immunogenic peptides to either naive or sensitized t cells. in contrast to dendritic cells (dc) present in the airway epithelium, those within the lung parenchyma do not readily engulf particulates and, therefore, other mechanisms must account for thei ...19948206508
listeria monocytogenes meningoencephalitis: the diagnostic importance of the csf lactic acid. 19948206777
glycine betaine confers enhanced osmotolerance and cryotolerance on listeria monocytogenes.listeria monocytogenes is a gram-positive food-borne pathogen that is notably resistant to osmotic stress and can grow at refrigerator temperatures. these two characteristics make it an insidious threat to public health. like several other organisms, l. monocytogenes accumulates glycine betaine, a ubiquitous and effective osmolyte, intracellularly when grown under osmotic stress. however, it also accumulates glycine betaine when grown under chill stress at refrigerator temperatures. exogenously ...19948288538
induction of cytokines in phagocytic mammalian cells infected with virulent and avirulent listeria strains.the present paper analyzes the cytokine response of mouse macrophages during infection by listeria monocytogenes. the use of different mutants of l. monocytogenes impaired in various steps of the infection process allowed us to dissect the cytokine response. cytokine mrna expression was detected by pcr-assisted amplification of rna extracted from macrophages after infection with different listeria strains. an increase in the amount of mrna for tumor necrosis factor alpha (tnf-alpha), interleukin ...19948300196
fate of listeria monocytogenes in murine macrophages: evidence for simultaneous killing and survival of intracellular bacteria.the intracellular survival of the ubiquitous pathogen listeria monocytogenes was studied in primary cultures of bone marrow-derived mouse macrophages. bacteria were able to grow rapidly in these cells, with an apparent multiplication rate of about 40 min. electron microscopy demonstrated that intracellular bacterial replication was the consequence of simultaneous intracellular killing and replication of bacteria in the same cells. within the first hour following phagocytosis, most bacteria were ...19948300212
bacterium-host cell interactions at the cellular level: fluorescent labeling of bacteria and analysis of short-term bacterium-phagocyte interaction by flow cytometry.flow cytometry is a potentially powerful tool for analyzing the interactions of facultative intracellular bacteria and macrophages on a cellular level, particularly when fluorochromes are used to label the bacteria. we labeled listeria monocytogenes and salmonella typhimurium with a lipophilic dye, pkh-2, and used flow cytometry to investigate phagocytosis by j774a.1 cells and short-term bacterial survival. labeled and unlabeled bacteria were identical in terms of viability, growth kinetics, and ...19948300223
macrophage-listeria interactions.it is clear that the interaction between macrophages and the facultative intracellular bacterium listeria monocytogenes is complex and dictated by the needs of both organisms. on the one hand, the invading pathogen has devised strategies to locate itself intracellularly in a site where host defense mechanisms are minimal; thus it escapes the phagosome and enters the cytoplasm, from which it travels to the next cell without exposing itself to the extracellular environment. on the other hand, the ...19948251578
perinatal listeriosis in a dutch woman returning from holiday in france.a case is reported of perinatal infection and fetal death due to listeria monocytogenes serotype 4b in a 28-weeks pregnant woman, who had spent her holiday in an area in france where an epidemic outbreak of listeriosis had occurred. sero- and phage-typing combined with sensitive dna-typing demonstrated that the listeria was identical to the strain responsible for the outbreak in france. although listeriosis appears to be an uncommon cause of perinatal infection, practicing obstetricians should b ...19948187925
gentamicin kills intracellular listeria monocytogenes.the purpose of the experiments described here was to test whether membrane-impermeant antibiotics present in the extracellular milieu could kill bacteria within macrophages. for this, mouse macrophage hybrids and elicited mouse peritoneal macrophages first were allowed to phagocytose the facultative intracellular bacterium listeria monocytogenes. the cells were incubated with or without gentamicin, and their bactericidal activity was measured. the results show that gentamicin caused normally non ...19948188344
treatment with anti-interleukin-10 monoclonal antibody enhances early resistance to but impairs complete clearance of listeria monocytogenes infection in mice.mice that received an anti-interleukin-10 (anti-il-10) neutralizing monoclonal antibody (mab) (sxc-1) prior to infection with listeria monocytogenes initially demonstrated resistance to the infection, as indicated by reduced recovery of l. monocytogenes from their spleens and livers during the first 5 days after challenge. anti-il-10 mab-treated mice then demonstrated reduced resistance during the later stage of infection, as indicated by persistent infection with l. monocytogenes in their liver ...19948188357
plasmid-borne cadmium resistance genes in listeria monocytogenes are similar to cada and cadc of staphylococcus aureus and are induced by cadmium.plm74 is the smallest known plasmid in listeria monocytogenes. it confers resistance to the toxic divalent cation cadmium. it contains a 3.1-kb ecori fragment which hybridizes with the cadac genes of plasmid pi258 of staphylococcus aureus. when introduced into cadmium-sensitive l. monocytogenes or bacillus subtilis strains, this fragment conferred cadmium resistance. the dna sequence of the 3.1-kb ecori fragment contains two open reading frames, cada and cadc. the deduced amino acid sequences ar ...19948188605
plasmid-borne cadmium resistance genes in listeria monocytogenes are present on tn5422, a novel transposon closely related to tn917.the complete (6,449-bp) nucleotide sequence of the first-described natural transposon of listeria monocytogenes, designated tn5422, was determined. tn5422 is a transposon of the tn3 family delineated by imperfect inverted repeats (irs) of 40 bp. it contains two genes which confer cadmium resistance (m. lebrun, a. audurier, and p. cossart, j. bacteriol. 176:3040-3048, 1994) and two open reading frames that encode a transposase (tnpa) and a resolvase (tnpr) of 971 and 184 amino acids, respectively ...19948188606
interaction of listeria species with human cell monolayers.in foodborne listeriosis, the first step of infection must be attachment to, and invasion of, the gastrointestinal epithelium by virulent listeria monocytogenes. virulence factors affecting this invasion are only now being determined. we examined the interaction of l. monocytogenes, serotypes 4b and 1/2a strains with "smooth" and "rough" characteristics. in addition, flagellated and non-flagellated isogenic strains altered by transposon mutagenesis were examined to study the effect of flagellae ...19948174317
[a case of listeria meningitis associated with systemic lupus erythematosus].we report a case of listeria meningitis associated with systemic lupus erythematosus (sle). the case is a 29-year-old female who was diagnosed as sle on august, 1982, and had been followed since then. on may 25, 1993, she was admitted to our hospital with complaints of fever, head ache and vomiting which developed 3 days before admission. an examination of the cerebro-spinal fluid (csf) revealed a cell count of (3664/3/mm3), protein concentration (123 mg/dl), and the quotient of csf (q albumin) ...19948176284
neutrophils are essential for early anti-listeria defense in the liver, but not in the spleen or peritoneal cavity, as revealed by a granulocyte-depleting monoclonal antibody.this study shows that in mice selectively depleted of neutrophils by treatment with a monoclonal antibody, rb6-8c5, listeriosis is severely exacerbated in the liver, but not in the spleen or peritoneal cavity during the crucial first day of infection. at sites of infection in the livers of neutrophil-depleted mice, listeria monocytogenes grew to large numbers inside hepatocytes. by contrast, in the livers of normal mice neutrophils rapidly accumulated at infectious foci and this was associated w ...19948270870
prolonged and effective blockade of tumor necrosis factor activity through adenovirus-mediated gene transfer.a chimeric protein capable of binding and neutralizing tumor necrosis factor (tnf) and lymphotoxin was expressed in mice transduced with a replication-incompetent adenoviral vector into which a tnf inhibitor gene had been engineered. within 3 days following the injection of 10(9) infectious particles, the tnf inhibitor concentration exceeded 1 mg/ml of plasma; this level of expression was maintained for at least 4 weeks, and detectable tnf inhibitory activity was measured 6 weeks after injection ...19948278368
diffuse petechial pustular lesions in a newborn. disseminated listeria monocytogenes. 19948304768
involvement of profilin in the actin-based motility of l. monocytogenes in cells and in cell-free extracts.within hours of listeria monocytogenes infection, host cell actin filaments form a dense cloud around the intracytoplasmic bacteria and then rearrange to form a polarized comet tail that is associated with moving bacteria. we have devised a cell-free extract system capable of faithfully reconstituting l. monocytogenes motility, and we have used this system to demonstrate that profilin, a host actin monomer-binding protein, is necessary for bacterial actin-based motility. we find that extracts fr ...19948313471
a simple rna probe system for analysis of listeria monocytogenes polymerase chain reaction products.[this corrects the article on p. 2796 in vol. 59.].199416349203
mode of action of nisin z against listeria monocytogenes scott a grown at high and low temperatures.nisin z, a natural nisin variant, was recently isolated from lactococcus lactis subspecies lactis nizo 22186. the gene for this lantibiotic, designated nisz, has been cloned, and its nucleotide sequence was found to be identical to that of the precursor nisin gene with the exception of a single mutation resulting in the substitution of asn-27 for his-27 in the mature polypeptide (j. w. m. mulders, i. j. boerrigter, h. s. rollema, r. j. siezen, and w. m. de vos, eur. j. biochem. 201:581-584, 1991 ...199416349286
a survey for listeria species, motile aeromonads and yersinia enterocolitica on bovine and ovine carcasses.one hundred ovine and 100 bovine carcasses in two abattoirs were sampled just after dressing for the presence of yersinia enterocolitica, listeria monocytogenes and motile aeromonads. yersinia enterocolitica was not isolated and only two samples were positive for listeria spp. in both cases, the listeria species were not normally pathogenic to man. in contrast, motile aeromonads were isolated from 81% of ovine and 35% of bovine carcasses.199416031739
inhibition of listeria monocytogenes by lactobacillus sake strains of meat origin.the ability of two lactobacillus sake strains of meat origin to inhibit the growth of listeria monocytogenes at 4, 8, 15, 24 and 32°c in a conventional liquid media was investigated. growth of l. monocytogenes was affected by lac. sake strains at all temperatures. the inhibition was higher at 15, 24 and 32°c than at refrigeration temperatures. the inhibitory activity of both lactobacilli was similar perhaps due to the fact that lac. sake 148 produces a bacteriocin inhibitory to l. monocytogenes, ...199422059605
survival of aeromonas hydrophila and listeria monocytogenes on fresh vegetables stored under moderate vacuum.storage at 6.5°c under moderate vacuum effectively prevented growth of aeromonas hydrophila on chicory endive, but had only a limited inhibitory effect on the growth of the organism on mung bean sprouts. growth of listeria monocytogenes on chicory endive was strongly stimulated under these conditions, whereas it was decreased on mung-bean sprouts.199424421192
endogenous endophthalmitis due to listeria monocytogenes.the authors report a case of listeria monocytogenes endophthalmitis in a patient who had undergone cardiac revascularization surgery and was receiving systemic corticosteroids. the organism was isolated both in the aqueous humor and in blood culture. the infection was successfully treated with intravenous crystalline penicillin, but the patient developed a bullous keratopathy and secondary glaucoma, resulting in poor visual acuity (counting fingers at 0.5 m). the visual acuity recovered to 20/30 ...199422823015
manufacturers have effect on listeriae.changes in food manufacturing and/or health education measures may have had an impact on the epidemiology of infections with listeria monocytogenes, researchers from leicester say.199327665816
presence and coincidence of listeria spp., motile aeromonads and yersinia enterocolitica in a cold-smoked salmon processing and packing plant.environmental samples and samples of partially processed fish from a cold-smoked salmon processing and packing plant, and product samples purchased from retail outlets, were examined for the presence of listeria monocytogenes and other listeria spp., motile aeromonads and yersinia enterocolitica. listeria spp. were not isolated from raw fish but were a contaminant of processed and partially processed fish. listeria spp. were also detected in 18.8% of surfaces in contact with fish. unlike listeri ...199316031699
common mechanistic action of bacteriocins from lactic acid bacteria.the influence of four bacteriocins from lactic acid bacteria on the proton motive force (pmf) of sensitive organisms was investigated. pediocin pa-1 (20 mug/ml) and leuconocin s (48.5 mug/ml) mediated total or major pmf dissipation of energized listeria monocytogenes scott a cells in a concentration-dependent manner, as has been shown for nisin. lactacin f (13.5 mug/ml) caused 87% pmf depletion of energized lactobacillus delbrueckii atcc 4797 cells, also in a concentration-dependent fashion. the ...199316349044
characterization by multilocus enzyme electrophoresis of listeria monocytogenes isolates involved in ovine listeriosis outbreaks in scotland from 1989 to 1991.initial results from a study of five small ovine listeriosis outbreaks in scotland in 1989 to 1991 are presented. forty-eight isolates including three from silage were typed at 10 polymorphic enzyme loci by using multilocus enzyme electrophoresis resulting in the identification of 12 electrophoretic types. phylogenetic analysis partitioned the 12 electrophoretic types into two statistically distinct divisions distinguishing 1/2a serotypes from non-1/2a serotypes.199316349052
detection and survival of listeria monocytogenes in milk and dairy products.detection of l. monocytogenes in raw and pasteurized milk, zabady, karish, domiati and romi cheeses were done in this study using direct and cold enrichment methods. out of 140 samples 3 samples were positive by cold enrichment and they were 2 of raw milk and one of domiati cheese. survival of l. monocytogenes was studied during heat treatment of milk by the sealed tube method of inactivation and it was found that l. monocytogenes inactivated completely at 60 degrees c for 15 minutes. there was ...199317265649
kinetics of antibody production against listeriolysin o in sheep with listeriosis.the kinetics of antibody production against listeriolysin o (llo), a major virulence factor of the intracellular bacterial pathogen listeria monocytogenes, was studied by dot blot analysis with highly purified llo during oral infection of sheep. specific antibodies appeared as soon as day 9 of an oral infection and peaked by day 20 of infection; specific antibody levels then remained almost stable for at least 4 months. a subclinical infecting dose (approximately 10(6) viable bacteria) was capab ...19938314995
surface-associated, prfa-regulated proteins of listeria monocytogenes synthesized under stress conditions.the expression of the five clustered genes of listeria monocytogenes: plca, hly, mpl, acta and plcb is under the control of the positive regulation factor prfa. listeriolysin, encoded by the hly gene, is the only prominent prfa-controlled gene product observed when l. monocytogenes strain nctc 7973 is cultured in a rich medium at 37 degrees c to the logarithmic growth phase. stress conditions such as heat-shock or stationary culture conditions lead to the induction of additional prfa-dependent p ...19938316076
rapid determination of listeria monocytogenes in foods using a resuscitation/selection/kit system detection.a resuscitation medium consisting of a trypticase soy broth base supplemented with 0.5% yeast extract, 0.25% sodium pyruvate, 0.01% sodium thioglycollate, and 0.1% chicken fat was used in the resuscitation of heat-injured and freeze-injured cells of listeria monocytogenes. after a resuscitation period of 4-h, the medium was made selective through the addition of nalidixic acid, acriflavin, and cycloheximide. the organisms were incubated in the selectivized medium at 35 degrees c for an additiona ...19938318857
enhanced conjugative transfer of plasmid dna from escherichia coli to staphylococcus aureus and listeria monocytogenes.transfer of mobilizable shuttle cloning vectors by conjugation from escherichia coli to staphylococcus aureus occurred at a very low frequency (10(-9) transconjugants per donor colony-forming unit after the mating period). it was observed that subinhibitory concentrations of penicillins (oxacillin or penicillin g) in the mating medium resulted in increased transfer frequency by conjugation of the shuttle vector pat18 from e. coli sm10 to s. aureus 80cr5 str (54-fold) and to listeria monocytogene ...19938319881
inhibition of psychrotrophic organisms by propionicin plg-1, a bacteriocin produced by propionibacterium thoenii.propionibacterium thoenii strain p127, which produces the bacteriocin propionicin plg-1, was grown in a skim milk medium and produced bacteriocin in that medium. no bacteriocin activity was detected in skim milk medium in which strain p127-1, a bacteriocin-negative variant of strain p127, had been grown. five psychrotrophic spoilage or pathogenic organisms (one strain each of listeria monocytogenes, pseudomonas fluorescens, vibrio parahaemolyticus, yersinia enterocolitica, and one strain of cory ...19938326023
comparison of "gen-probe" dna probe and pcr for detection of listeria monocytogenes in naturally contaminated soft cheese and semi-soft cheese.a comparison was made of three approaches for the detection of listeria monocytogenes in naturally contaminated soft cheese and semi-soft cheese after enrichment. enrichment broths were tested by plating them onto different selective agars, by "gen probe" dna hybridization and by the polymerase chain reaction (pcr). based on two-step enrichment, all three approaches showed high specificities (90% or more) in detecting l. monocytogenes. in contrast, the sensitivity of the gen-probe test was low ( ...19938327782
reduction of ferric iron by listeria monocytogenes and other species of listeria.one mechanism by which listeria monocytogenes is thought to obtain iron required for growth is through the extracellular reduction of a ferric iron source to the ferrous form. to better characterize this reductase activity we have developed a simple plate assay that allows detection of colonies of listeria species able to reduce ferric iron. cells are plated on an agar base medium containing a ferric iron source and ethylenediamine dihydroxyphenylacetic acid. colonies are then overlain with soft ...19938330259
nonspecific phospholipase c of listeria monocytogenes: activity on phospholipids in triton x-100-mixed micelles and in biological membranes.listeria monocytogenes secretes a phospholipase c (plc) which has 39% amino acid sequence identity with the broad-specificity plc from bacillus cereus. recent work indicates that the l. monocytogenes enzyme plays a role during infections of mammalian cells (j.-a. vazquez-boland, c. kocks, s. dramsi, h. ohayon, c. geoffroy, j. mengaud, and p. cossart, infect. immun. 60:219-230, 1992). the homogeneous enzyme has a specific activity of 230 mumol/min/mg when phosphatidylcholine (pc) is dispersed in ...19938331063
expression of listeriolysin and phosphatidylinositol-specific phospholipase c is repressed by the plant-derived molecule cellobiose in listeria monocytogenes.the primary habitat of the intracellular pathogen listeria monocytogenes is considered to be soil and decaying vegetation. as an opportunistic pathogen it must be able to recognize its entry into host tissue and, in response, co-ordinately induce the expression of virulence factors. no signature molecule, which facilitates this regulation, has been identified for any human pathogen. our studies have demonstrated for the first time that the expression of major virulence determinants in l. monocyt ...19938332058
purification and characterization of a 58-kda cell wall-associated protein from listeria monocytogenes.a cell wall protein (p58) was purified from listeria monocytogenes by detergent extraction and superose 6 gel chromatography. it had a molecular mass of 58 kda, was strongly hydrophobic, contained reactive thiol group(s) and was located at least partially on the surface of bacterial cells. production of this protein varied among different listeria, being the most prominent in nctc 7973 of l. monocytogenes, weaker in four other strains of this species and undetectable in tested strains of l. seel ...19938332104
Refresh
firstprev
...121122123124125126127128129130...
nextlast
Displaying items 12601 - 12700 of 16792