Publications

TitleAbstractYear(sorted descending)
Filter
PMID
Filter
optimization of the detection of bacteriophages induced from listeria sp.it is necessary to isolate new phages in order to improve the rate of typeability of listeria monocytogenes strains. we propose a method which increases the detection of induced phages in the presence of inhibitory substances synthesized or liberated by the cells during phage production. of the 29 phages isolated, 11 (38%) were detected by the spot-on-the-lawn technique and 18 (62%) were revealed by the soft-agar technique. to increase the rate of phage detection, both techniques appear useful. ...19979024005
a case of foodborne listeriosis in sweden.a 70-year-old woman fell seriously ill overnight with meningitis and was admitted to hospital. cerebrospinal fluid culture yielded listeria monocytogenes. one of the first problems in solving a human case of listeriosis suspected to be foodborne is to find the foods likely to have been transmitting l. monocytogenes. two enrichment procedures and a direct plating procedure were used for isolation of the bacteria from different food items collected from the patient's refrigerator, local retail sto ...19979024007
[green amniotic fluid as initial symptom of high intestinal obstruction in infants].at the birth of two children the amniotic fluid was green colored. the apgar scores were good. because of bilious vomiting and food retention, respectively, an open stomach tube was inserted, out of which bilious stomach contains were drained. the cause of green amniotic fluid was not meconium production or infection with listeria monocytogenes, but mixing with green bile. at further investigation the children both proved to have a high intestinal obstruction distal of the papilla duodeni major.19979064529
a role for macrophage scavenger receptors in atherosclerosis and susceptibility to infection.macrophage type-i and type-ii class-a scavenger receptors (msr-a) are implicated in the pathological deposition of cholesterol during atherogenesis as a result of receptor-mediated uptake of modified low-density lipoproteins (mldl). msr-a can bind an extraordinarily wide range of ligands, including bacterial pathogens, and also mediates cation-independent macrophage adhesion in vitro. here we show that targeted disruption of the msr-a gene in mice results in a reduction in the size of atheroscle ...19979069289
abm-1 and abm-2 homology sequences: consensus docking sites for actin-based motility defined by oligoproline regions in listeria acta surface protein and human vasp.actin-based motility involves a cascade of binding interactions designed to assemble actin regulatory proteins into functional locomotory units. listeria acta surface protein contains a series of nearly identical efpppptde-type oligoproline sequences for binding vasodilator-stimulated phosphoprotein (vasp). the latter is a tetrameric protein with numerous gpp-ppp docking sites for profilin, a 15 kda regulatory protein that promotes actin filament assembly. analysis of known actin regulatory prot ...19979070872
listeria monocytogenes infection of hela cells results in listeriolysin o-mediated transient activation of the raf-mek-map kinase pathway.in this study we investigated the effect of listeria monocytogenes infection on the activation of the raf-mek-map kinase pathway in eukaryotic host cells. hela cell infection with l. monocytogenes egd resulted in a rapid, but transient, phosphorylation of the map kinases erk-1 and erk-2, a transient phosphorylation of the map kinase kinase mek-1, and a transient activation of the map kinase kinase kinase raf. in parallel to the transient phosphorylation of the map kinases, we detected induced ex ...19979084147
accelerating on a treadmill: adf/cofilin promotes rapid actin filament turnover in the dynamic cytoskeleton. 19979087434
actin depolymerizing factor (adf/cofilin) enhances the rate of filament turnover: implication in actin-based motility.actin-binding proteins of the actin depolymerizing factor (adf)/cofilin family are thought to control actin-based motile processes. adf1 from arabidopsis thaliana appears to be a good model that is functionally similar to other members of the family. the function of adf in actin dynamics has been examined using a combination of physical-chemical methods and actin-based motility assays, under physiological ionic conditions and at ph 7.8. adf binds the adp-bound forms of g- or f-actin with an affi ...19979087445
xenopus actin depolymerizing factor/cofilin (xac) is responsible for the turnover of actin filaments in listeria monocytogenes tails.in contrast to the slow rate of depolymerization of pure actin in vitro, populations of actin filaments in vivo turn over rapidly. therefore, the rate of actin depolymerization must be accelerated by one or more factors in the cell. since the actin dynamics in listeria monocytogenes tails bear many similarities to those in the lamellipodia of moving cells, we have used listeria as a model system to isolate factors required for regulating the rapid actin filament turnover involved in cell migrati ...19979087446
bacterial infections.non-opportunistic bacterial infections are an important cause of morbidity and mortality for hiv-infected adults and children. factors associated with increased risk of these include altered b- and t-cell function; altered phagocytic cell function; skin and mucous membrane defects; and use of indwelling vascular catheters, antibiotics, or cytotoxic agents. the pathogens encountered most frequently are s. aureus, s. pneumoniae, h. influenzae, salmonella sp., and pseudomonas aeruginosa. less commo ...19979093231
adaptation to sublethal environmental stresses protects listeria monocytogenes against lethal preservation factors.a sublethal dose of ethanol (5%, vol/vol), acid (hcl, ph 4.5 to 5.0), h2o2 (500 ppm), or nacl (7%, wt/vol) was added to a listeria monocytogenes culture at the exponential phase, and the cells were allowed to grow for 1 h. exponential-phase cells also were heat shocked at 45 degrees c for 1 h. the stress-adapted cells were then subjected to the following factors at the indicated lethal levels--nacl (25%, wt/vol), ethanol (17.5%, vol/vol), hydrogen peroxide (0.1%, wt/vol), acid (ph 3.5), and star ...19979097420
typing listeria monocytogenes isolates from fish products and human listeriosis cases.seventy-two listeria monocytogenes isolates originating from 10 different fish products of 12 producers and 47 isolates from human listeriosis cases were typed by serotyping and multilocus enzyme electrophoresis. seventy-five of these isolates were further subtyped by restriction analysis of genomic dna with the enzyme xhoi and by pulsed-field gel electrophoresis using the enzymes apai and smai. the results show that several l. monocytogenes clones identified by multilocus enzyme electrophoresis ...19979097430
identification, cloning, and characterization of the ima operon, whose gene products are unique to listeria monocytogenes.the lmaa gene of listeria monocytogenes encodes a protein capable of inducing delayed-type hypersensitivity reactions in l. monocytogenes-immune mice (s. göhmann, m. leimeister-wachter, e. schiltz, w. goebel, and t. chakraborty, m. microbiol. 4:1091-1099, 1990). here we show that it is the last gene of the lma operon, which now comprises four genes, lmadcba. maxicell analysis of peptides encoded by the lma operon identified four polypeptides of 16.7, 16.4, 14.9, and 21 kda which correspond to th ...19979098070
recombination between a resident plasmid and the chromosome following irradiation of the radioresistant bacterium deinococcus radiodurans.interplasmidic and intrachromosomal recombination in deinococcus radiodurans has been studied recently and has been found to occur at high frequency following exposure to ionizing radiation. in the current work, we document plasmid-chromosome recombination following exposure of d. radiodurans to 1.75 mrad (17.5 kgy) 60co, when the plasmid is present in the cell at the time of irradiation. recombination is assayed using both physical and allelic polymorphisms of homologous genes in the plasmid an ...19979099885
internalized listeria monocytogenes modulates intracellular trafficking and delays maturation of the phagosome.previous studies have shown that early phagosome-endosome fusion events following phagocytosis of listeria monocytogenes are modulated by the live organism. in the present study, we have characterized more fully the intracellular pathway of dead and live listeria phagosomes. to examine access of endosomal and lysosomal markers to phagosomes containing live and dead listeria, quantitative electron microscopy was carried out with intact cells using internalized bsa-gold as a marker to quantify tra ...19979099947
bystander activation of cytotoxic t cells: studies on the mechanism and evaluation of in vivo significance in a transgenic mouse model.bystander activation, i.e., activation of t cells specific for an antigen x during an immune response against antigen y may occur during viral infections. however, the low frequency of bystander-activated t cells has rendered it difficult to define the mechanisms and possible in vivo relevance of this nonspecific activation. this study uses transgenic mice expressing a major histocompatibility complex class i-restricted tcr specific for glycoprotein peptide 33-41 of lymphocytic choriomeningitis ...19979104811
the isolated comet tail pseudopodium of listeria monocytogenes: a tail of two actin filament populations, long and axial and short and random.listeria monocytogenes is driven through infected host cytoplasm by a comet tail of actin filaments that serves to project the bacterium out of the cell surface, in pseudopodia, to invade neighboring cells. the characteristics of pseudopodia differ according to the infected cell type. in ptk2 cells, they reach a maximum length of approximately 15 microm and can gyrate actively for several minutes before reentering the same or an adjacent cell. in contrast, the pseudopodia of the macrophage cell ...19979105044
management of listeriosis.determination of the mic in vitro is often used as the basis for predicting the clinical efficacy of antibiotics. listeriae are uniformly susceptible in vitro to most common antibiotics except cephalosporins and fosfomycin. however, the clinical outcome is poor. this is partially because listeriae are refractory to the bactericidal mechanisms of many antibiotics, especially to ampicillin-amoxicillin, which still is regarded as the drug of choice. a true synergism can be achieved by adding gentam ...19979105758
culture-negative listeriosis of the central nervous system diagnosed by detection of antibodies to listeriolysin o. 19979105851
sample preparation and dna extraction procedures for polymerase chain reaction identification of listeria monocytogenes in seafoods.five grams of seafood products were inoculated with one to 500 viable or 10(9) heat-killed cells of listeria monocytogenes. the presence of the pathogen was detected by the polymerase chain reaction (pcr) with primers specific for fragments of the listeriolysin o (hly) gene (two sets) and for the invasion-associated protein (iap) gene (one set). for dna preparation, boiling, either alone or in combination with lysozyme and proteinase k treatment, was not always sufficient to lyse l. monocytogene ...19979105938
pcr detection of listeria monocytogenes in 'gravad' rainbow trout.'gravad' rainbow trout artificially contaminated with listeria monocytogenes was analyzed by use of a 4 h enrichment period followed by extraction of dna and pcr amplification. this procedure made it possible to detect 10-100 cfu l. monocytogenes per gram 'gravad' rainbow trout, within 12 h. after a prolonged enrichment period of 24 h, numbers as low as 1-10 cfu l. monocytogenes per gram could be detected. the method described may be a useful tool for screening samples of 'gravad' rainbow trout ...19979105939
nisin induces changes in membrane fatty acid composition of listeria monocytogenes nisin-resistant strains at 10 degrees c and 30 degrees c.listeria monocytogenes isolates resistant to 10(5) iu ml-1 nisin were obtained at 30 degrees c (nr30) and at 10 degrees c (nr10). nisin prolonged the lag phase of isolate nr30 at 10 degrees c. isolates nr30 and nr10 did not produce a nisinase. protoplasts of isolate nr30 were unaffected by exposure to nisin. the fatty acid composition from the wild-type strain and nr isolates was determined. as expected, temperature-induced differences in the c15/c17 fatty acid ratios were found. growth of the n ...19979113875
mice heterozygous for a deletion of the tumor necrosis factor-alpha and lymphotoxin-alpha genes: biological importance of a nonlinear response of tumor necrosis factor-alpha to gene dosage.the tumor necrosis factors (tnf-alpha and lymphotoxin, or lt-alpha) are important mediators of the immune and inflammatory responses, and it has been proposed that a positive feedback loop could boost the expression of the tnf to sufficiently high levels to fend off infections. to investigate this phenomenon and its biological consequences, we have generated lt-alpha/tnf-alpha knockout mice and compared mice having one or two functional lt-alpha/tnf-alpha alleles. in response to lipopolysacchari ...19979130661
identification of two regions in the n-terminal domain of acta involved in the actin comet tail formation by listeria monocytogenes.the acta protein of listeria monocytogenes induces actin nucleation on the bacterial surface. the continuous process of actin filament elongation provides the driving force for bacterial propulsion in infected cells or cytoplasmic extracts. here, by fusing the n-terminus of acta (residues 1-234) to the omega fragment of beta-galactosidase, we present the first evidence that this domain contains all the necessary elements for actin tail formation. a detailed analysis of acta variants, in which sm ...19979130698
effects of il-13 on murine listeriosis.acquired resistance against listeria monocytogenes is a typical t helper (th) 1 dominated immune response, whereas th2 cytokines are thought to worsen listeriosis. we investigated effects of recombinant il-13 (ril-13) on the host response to l. monocytogenes in mice. although il-13 has been described as a th2 cytokine with deactivating anti-inflammatory activities, it was found to enhance antilisterial resistance. in vitro, ril-13 increased il-12 p40 and p70 production by bone marrow macrophages ...19979138006
tcr-mediated target cell lysis by cd4+nk1+ liver t lymphocytes.in the liver, an unusual t lymphocyte population exists with the intriguing phenotype cd4+nk1+ tcr alpha beta int. thus far, functions of these lymphocytes remained elusive. recently, however, cd4+nk1+ liver t lymphocytes have been shown to produce cytokines. here we show that sorted cd4+nk1+ liver lymphocytes from naive mice lyse target cells after tcr alpha beta or cd3, but not tcr gamma delta, engagement. liver lymphocytes from beta 2-microglobulin-deficient gene disruption mutant mice failed ...19979138017
bacterial phospholipases and their role in virulence.virulence of many bacterial pathogens is based, at least in part, on the action of phospholipases. the consequences may be immediate and direct, as in the action of clostridium perfringens alpha toxin on red cells or platelets, or subtle, as with phosphatidylinositol-specific phospholipases of listeria monocytogenes and other bacteria.19979141190
effective adjuvants for the induction of antigen-specific delayed-type hypersensitivity.vaccines utilizing poorly immunogenic subunit antigens are dependent upon adjuvants to drive the appropriate t cell responses. in an effort to determine the ability of several adjuvants to promote cell-mediated immunity (cmi), we assessed delayed-type hypersensitivity (dth) in mice inoculated with heat-killed listeria monocytogenes (hklm) vaccines. the vaccines were formulated as oil-in-water emulsions containing one or more of the following bacterial-derived immunostimulators: mpl immunostimula ...19979141210
influenza-specific immunity induced by recombinant listeria monocytogenes vaccines.in this study, we evaluate two listeria monocytogenes strains that express influenza nucleoprotein (np) sequences for their ability to protect against challenge with influenza-virus. the construction of one strain, which expresses only the kd restricted np epitope (np 147-155), is described in this study; the other strain, which expresses the full np sequence in the form of a fusion protein, has been described previously. the ability of the two strains to present the kd restricted np epitope in ...19979141215
use of an excision reporter plasmid to study the intracellular mobility of the conjugative transposon tn916 in gram-positive bacteria.an excision reporter plasmid was constructed to characterize the intracellular mobility of tn916 in various gram-positive bacteria. the reporter component of this plasmid is a chloramphenicol-resistance gene which has been insertionally inactivated with the integrative vector pat112 containing the attachment site of tn916. tn916-mediated excision of pat112, to produce clones resistant to chloramphenicol, was detected in enterococcus faecalis bm4110, listeria monocytogenes l028-str and streptococ ...19979141688
diagnosis and treatment of pustular disorders in the neonate.the diagnosis of a pustular dermatosis occurring during the first months of life is usually based on clinical findings. however, some cases may require simple investigations including microscopic examination of pustular content, cultures, and skin biopsies. the main benign transient neonatal types of pustulosis include erythema toxicum neonatorum, infantile acropustulosis, transient neonatal pustular melanosis, and neonatal acne. the most common causes of infectious pustular skin lesions include ...19979144701
listeria monocytogenes infection in mice treated with pentoxifylline.the course of l. monocytogenes infection was followed in mice treated with pentoxifylline (pof), a known inhibitor of endogenous tumor necrosis factor (tnf) formation. administration of pof caused a delay in l. monocytogenes elimination which was probably related to a reduction the listericidal activity of macrophages and to an attenuation of delayed type hypersensitivity (dth) to listeria antigens. in spite of this, some pof-treated mice were protected from lethal effects of virulent l. monocyt ...19979144910
neonatal meningitis due to multi-resistant listeria monocytogenes. 19979145834
antibacterial effect of the adhering human lactobacillus acidophilus strain lb.the spent culture supernatant of the human lactobacillus acidophilus strain lb produces an antibacterial activity against a wide range of gram-negative and gram-positive pathogens. it decreased the in vitro viability of staphylococcus aureus, listeria monocytogenes, salmonella typhimurium, shigella flexneri, escherichia coli, klebsiella pneumoniae, bacillus cereus, pseudomonas aeruginosa, and enterobacter spp. in contrast, it did not inhibit lactobacilli and bifidobacteria. the activity was heat ...19979145867
emergence of the trimethoprim resistance gene dfrd in listeria monocytogenes bm4293.the sequence of the trimethoprim resistance gene of the 3.7-kb plasmid (pip823) that confers high-level resistance (mic, 1,024 microg/ml) to listeria monocytogenes bm4293 was determined. the gene was identical to dfrd recently detected in staphylococcus haemolyticus mur313. the corresponding protein, s2dhfr, represents the second class of high-level trimethoprim-resistant dihydrofolate reductase identified in gram-positive bacteria. we propose that trimethoprim resistance in l. monocytogenes bm4 ...19979145882
antibacterial peptides of bovine lactoferrin: purification and characterization.three peptides with antibacterial activity toward enterotoxigenic escherichia coli have been purified from a pepsin digest of bovine lactoferrin. all peptides were cationic and originated from the n-terminus of the molecule in a region where a bactericidal peptide, lactoferricin b, had been previously identified. the most potent peptide, peptide i, was almost identical to lactoferricin b; the sequence corresponded to residues 17 to 42, and the molecular mass was 3195 as determined by mass spectr ...19979149961
food poisoning, listeriosis, and febrile gastroenteritis.outbreaks of foodborne disease owing to contamination with listeria monocytogenes bacteria have usually been associated with the development of severe invasive disease. a recent report has provided clear documentation showing that outbreaks of l. monocytogenes also present as gastroenteritis and fever. further studies of this foodborne organism are needed to determine its infectious dose and the characteristics of the host that are associated with noninvasive febrile gastroenteritis.19979155220
listeria endocarditis: current management and patient outcome--world literature review.this is believed to be the 58th reported case of listeria monocytogenes infective endocarditis. published reports worldwide were reviewed as to treatment, outcome, and prognostic features. there is controversy over whether all patients with this condition should have surgery. moreover the best antibiotic treatment is not known, which accounts for the heterogeneity of regimens used. listeria endocarditis has a high mortality rate (37%). this was higher in men (41% v 32%) and in patients with valv ...19979155624
primary listeria monocytogenes infection in gestating mice.the facultative intracellular gram-positive bacterium listeria monocytogenes is a food-borne pathogen of frequently underestimated importance. pregnant women represent the high-risk group for l. monocytogenes infection. abortion, stillbirth or neonatal infection can be the serious outcome of such an infection. recovery from listeriosis, resistance mechanisms of the host and the effect of l. monocytogenes on fetal development still remain to be fully understood. the results of our experiments sho ...19979161004
monitoring the microbiology of high quality milk by monthly sampling over 2 years.the concentrations of seven types of microorganism in the milk produced by farms using high quality milking procedures were monitored monthly. the most commonly encountered bacterium was pseudomonas, whose concentration varied greatly between samples, but lactococci, lactobacilli and yeasts were also present at more stable concentrations. staphylococcus aureus and beta-glucuronidase-positive escherichia coli were occasionally detected. listeria monocytogenes was found in the samples from only on ...19979161919
cell motility: complex dynamics at the leading edge.the intracellular pathogen listeria monocytogenes is a useful model for general actin-based cell motility, because it recruits host actin and associated proteins for movement. recent data have shown that these associated proteins include the ena/vasp family of proteins and the actin-related proteins arp2 and arp3.19979162480
serological diagnosis of bovine, caprine, and ovine mastitis caused by listeria monocytogenes by using an enzyme-linked immunosorbent assay.an enzyme-linked immunosorbent assay for detecting listeria monocytogenes antibodies in bovine (n = 35), caprine (n = 27), and ovine (n = 30) milk samples was evaluated by comparison with bacteriological examination. microtiter plates were coated with proteins obtained from culture supernatant, and antibodies were revealed with a monoclonal antibody able to react with the immunoglobulins belonging to the three animal species. the arithmetic mean optical density (od) of milk samples infected with ...19979163495
detection and identification of listeria monocytogenes from milk and cheese by a single-step pcr.primers of iap gene were used as a target to develop a pcr technique for detecting listeria monocytogenes in milk and cheese. the pcr technique gives good results in the detection of listeria monocytogenes either in artificially or naturally contaminated foodstuffs and has a high sensitivity and specificity. application of this rapid diagnostic tool could provide further information about the spread of l. monocytogenes in milk and cheese.19979163724
multifocal defects in immune responses in relb-deficient mice.mice with a targeted disruption of the rel/nuclear factor-kappab family member relb develop a complex inflammatory phenotype, myeloid hyperplasia, and splenomegaly due to extramedullary hemopoiesis. in this work, we report that relb-deficient mice, in addition to the pathologic changes, were highly susceptible to infection by the facultative intracellular bacterium listeria monocytogenes. relb binds transcriptionally active kappab motifs in the tnf-alpha promoter in normal cells, and in vitro st ...19979164938
impaired macrophage listericidal and cytokine activities are responsible for the rapid death of listeria monocytogenes-infected ifn-gamma receptor-deficient mice.ifn-gamma receptor-deficient (ifn-gammar -/-) mice were used to study the innate immune responses during infection with listeria monocytogenes. mutant mice were unable to limit bacterial growth and died of sepsis even with an infection dose of 70 listeria. at day 2, they showed an exacerbated listeriosis and mice succumbed to infection before the onset of an effective specific immunity, demonstrating a defective innate immunity. recruitment and extravasation of phagocytic cells to infected organ ...19979164949
listeria monocytogenes infection of cultured endothelial cells stimulates neutrophil adhesion and adhesion molecule expression.microbial infection of the endothelium with the resultant up-regulation of adhesion molecule expression and stimulated leukocyte adhesion to endothelial cells can promote an inflammatory response. previous work demonstrated that listeria monocytogenes can replicate within cultured endothelial cells; thus, we tested whether l. monocytogenes infection of huvec stimulated an inflammatory phenotype on these cells. infection with 10(4) cfu of bacteria increased neutrophil adhesion to huvec 40-fold an ...19979164950
listeriosis after fludarabine treatment for chronic lymphocytic leukemia.the authors report a case of listeria monocytogenes septicemia in a patient with advanced cll after a single course of fludarabine, without any other immunosuppressive therapy e.g. corticosteroids. the immunosuppressive action of fludarabine in patients who are already severely immunosuppressed must be considered from a diagnostic and therapeutic point of view. listeriosis and other opportunistic infections, like pneumocystis carinii pneumonia, have been reported during and after treatment with ...19979168306
broad-spectrum antimicrobial activity of human intestinal defensin 5.defensins are antibiotic peptides expressed in human and animal myeloid and epithelial cells. due to the limited availability of natural peptides, the properties of human epithelial defensins have not been studied. we assayed the microbicidal activity of recombinant human intestinal defensin 5 (rhd-5) in the presence of salt (o to 150 mm nacl) with varied ph (ph 5.5 to ph 8.5) and trypsin (25 and 250 microg/ml). rhd-5 exhibits microbicidal activity against listeria monocytogenes, escherichia col ...19979169780
isolation and characterization of a listeria monocytogenes mutant strain hyperproducing virulence factors.a mutant strain characterized by hyperproduction of a number of cell wall and supernatant proteins was isolated after n'methyl-n'-nitro-n-nitrosoguanidine treatment of listeria monocytogenes strain nctc10527. several of these proteins were identified as virulence factors. when a wild-type strain was grown in the presence of activated charcoal it was shown to exhibit the same protein pattern as the isolated mutant.19979170261
expanded models for the non-thermal inactivation of listeria monocytogenes.previously developed four-variable response surface models for describing the effects of temperature, ph/lactic acid, sodium chloride and sodium nitrite on the time to achieve a 4-log, non-thermal inactivation (t4d) of listeria monocytogenes in aerobic, acidic environments were expanded to five-variable models that distinguish the effects of ph and acidulant concentration. a total of 18 new variable combinations were evaluated and the inactivation kinetics data appended onto a consolidation of t ...19979172398
prevalence of listeria sp. in droppings from urban rooks (corvus frugilegus).droppings from 112 urban rooks (corvus frugilegus) were cultured for the presence of listeria sp. overall, 46% of rooks sampled harboured one or more listeria species. of all birds examined, 33%, 24% and 8%, respectively, were infected with listeria monocytogenes, listeria innocua and listeria seeligeri. differentiation of l. monocytogenes and l. seeligeri carried out by several phenotypic typing methods proved the diversity of strains and the major role of rooks which widely contribute to sprea ...19979172407
the use of the bacteriocin, nisin, as a preservative in ricotta-type cheeses to control the food-borne pathogen listeria monocytogenes.the efficacy of nisin to control the food-borne pathogen listeria monocytogenes in ricotta-type cheeses over long storage (70 d) at 6-8 degrees c was determined. cheeses were prepared from unpasteurized milk by direct acidification with acetic acid (final ph 5.9) and/or calcium chloride addition during heat treatment. nisin was added in the commercial form of nisaplin pre-production to the milk. each batch of cheese was inoculated with 10(2)-10(3) cfu g-1 of a five-strain cocktail of l. monocyto ...19979172439
optimization of haemolysis in enhanced haemolysis agar (eha)--a selective medium for the isolation of listeria monocytogenes.the presence of listeria monocytogenes in enrichment media can be masked by faster growth of other listeria spp. therefore, enhanced haemolysis agar (eha) is a good alternative for another isolation media, because the presence of a few l. monocytogenes colonies can be detected in a majority of colonies of other listeriae on the basis of haemolysis. in this study the haemolysis reaction in eha was optimized. in a collaborative study using reference samples, no significant differences in counts on ...19979172448
nosocomial infections by listeria monocytogenes: analysis of a cluster of septicemias in immunocompromised patients.from december 1994 to november 1995 an unusual accumulation of listeria infections occurred at the university hospital hamburg-eppendorf, germany. eleven immunosuppressed patients from different departments developed septicemia due to listeria monocytogenes during hospitalization. in a retrospective study, serotyping and pulsed-field gel electrophoresis revealed that six isolates were identical or genetically related. four of them had been isolated from renal transplant recipients. listeria mono ...19979181378
dietary fish oil enhances circulating interferon-gamma in mice during listeriosis without altering in vitro production of this cytokine.the objective of this study was to investigate the impact of feeding mice a diet rich in n-3 polyunsaturated fatty acids (pufa) from fish oil on the interferon-gamma (ifn-gamma) response during an active infection with listeria monocytogenes. weanling female c3h/hen mice were fed experimental diets containing 20% by weight one of the following fats: soybean oil, lard, or a mixture of menhaden fish oil and corn oil (17:3, w/w). after 4 weeks, mice were injected with 10(5) live l. monocytogenes, a ...19979181465
proteolytic pathways of activation and degradation of a bacterial phospholipase c during intracellular infection by listeria monocytogenes.listeria monocytogenes is a facultative intracellular bacterial pathogen that spreads cell to cell without exposure to the extracellular environment. bacterial cell-to-cell spread is mediated in part by two secreted bacterial phospholipases c (plc), a broad spectrum plc (pc-plc) and a phosphatidylinositolspecific plc (pi-plc). pi-plc is secreted in an active state, whereas pc-plc is secreted as an inactive proenzyme (propc-plc) whose activation is mediated in vitro by an l. monocytogenes metallo ...19979182669
persistent production of interferon-gamma (ifn-gamma) and il-12 is essential for the generation of protective immunity against listeria monocytogenes.ifn-gamma and il-12 are believed to be important in the host defence against listeria infection in mice. however, the relationship between these two cytokines and generation of protective immunity remains poorly understood. in the present study, it was found that at least 4 days of immunizing infection were required for the generation of protective immunity against l. monocytogenes. protective immunity was generated only by immunizing infection with virulent strain. even repeated injections of a ...19979182892
inhibition of gamma interferon synthesis by catecholamines.in vitro incubation of listeria monocytogenes immune spleen cells in the presence of the catecholamines epinephrine or norepinephrine inhibited the gamma interferon (ifn-gamma) synthesis induced by the mitogen pha, in a manner that appeared to be concentration dependent. moreover, the inhibitory effect of both catecholamines epinephrine and norepinephrine on the synthesis of ifn-gamma was prevented by incubating immune spleen cells in the presence of propranolol, a beta adrenergic antagonist age ...19979184628
mice lacking reduced nicotinamide adenine dinucleotide phosphate oxidase activity show increased susceptibility to early infection with listeria monocytogenes.mice lacking the gp91 protein of reduced nicotinamide adenine dinucleotide phosphate oxidase showed heightened susceptibility to listeria infection. the enhanced susceptibility was noted 2 days after infection, the usual peak time of the neutrophil-dependent lesion in the liver. infected gp91phox -/- mice had an increase of approximately 30-fold in listeria in the liver and an increase in the number of microabscesses. the study of the gp91phox mice underscores the early role of the neutrophil an ...19979190903
listeria monocytogenes-induced liver abscess in pregnancy. 19979197456
ribotypes and virulence gene polymorphisms suggest three distinct listeria monocytogenes lineages with differences in pathogenic potential.a total of 133 listeria monocytogenes isolates were characterized by ribotyping and allelic analysis of the virulence genes hly, acta, and inla to uncover linkages between independent phylogenetic and specific virulence markers. pcr-restriction fragment length polymorphisms revealed 8 hly, 11 inl4, and 2 acta alleles. the combination of these virulence gene alleles and ribotype patterns separated l. monocytogenes into three distinct lineages. while distinct hly and inla alleles were generally fo ...19979199440
utilization of iron-catecholamine complexes involving ferric reductase activity in listeria monocytogenes.listeria monocytogenes is a ubiquitous potentially pathogenic organism requiring iron for growth and virulence. although it does not produce siderophores, l. monocytogenes is able to obtain iron by using either exogenous siderophores produced by various microorganisms or natural catechol compounds widespread in the environment. in the presence of tropolone, an iron-chelating agent, growth of l. monocytogenes is completely inhibited. however, the growth inhibition can be relieved by the addition ...19979199450
effects of ph and salinity on the antimicrobial properties of clavanins.clavanins are histidine-rich, amidated alpha-helical antimicrobial peptides that were originally isolated from the leukocytes (hemocytes) of a tunicate, styela clava. the activities of clavanin a amide and clavanin a acid against escherichia coli, listeria monocytogenes, and candida albicans were substantially greater at ph 5.5 than at ph 7.4. in contrast, clavanin ak, a synthetic variant of clavanin a acid containing 4 histidine-->lysine substitutions exerted substantial activity at both ph 7.4 ...19979199465
il-4 secretion by cd4+ nk1+ t cells induces monocyte chemoattractant protein-1 in early listeriosis.il-4 is a major promotor of th2 differentiation and an antagonist of ifn-gamma production. although experimental listeriosis is characterized by a th1 response, il-4-producing cells were detected in spleens of mice promptly after listeria monocytogenes infection. we identified this early il-4 as inducer of the chemokine, monocyte chemoattractant protein-1 (mcp-1), which mainly attracts monocytes/macrophages, but not neutrophils. mcp-1-secreting cells were demonstrable in spleens of mice infected ...19979200431
bioactivity of selected plant essential oils against listeria monocytogenes.ninety-three different commercial essential oils were screened for activity against 20 listeria monocytogenes strains in vitro and the results correlated against the actual chemical composition of each oil. there was a substantial difference in the activity between different essential oils as expected, but there was also a difference in activity between different samples of the same essential oil. strong anti-listeria activity was often correlated with essential oils containing a high percentage ...19979202441
fate of low temperature and acid-adapted yersinia enterocolitica and listeria monocytogenes that contaminate lactic acid decontaminated meat during chill storage.pathogens found in the environment of abattoirs may become adapted to lactic acid used to decontaminate meat. such organisms are more acid tolerant than non-adapted parents and can contaminate meat after lactic acid decontamination (lad). the fate of acid-adapted yersinia enterocolitica and listeria monocytogenes, inoculated on skin surface of pork bellies 2 h after lad, was examined during chilled storage. lad included dipping in 1%, 2% or 5% lactic acid solutions at 55 degrees c for 120 s. lad ...19979202443
research note: in vitro inhibition of listeria monocytogenes growth by veillonellae cultures grown on tartrate media.veillonellae cultures were grown on agar media supplemented with tartrate and examined for inhibitory effects on the growth of listeria monocytogenes. veillonellae cultures grown on media supplemented with 0 or 50 mmol l-1 of tartrate did not inhibit the growth of l. monocytogenes; however, veillonellae grown on media supplemented with 100, 150 or 200 mmol l-1 of tartrate did inhibit the growth of l. monocytogenes. the inhibition of the growth of l. monocytogenes by the veillonellae was correlat ...19979202444
a comparison of immunomagnetic and surface adhesion immunofluorescent techniques for the rapid detection of listeria monocytogenes and listeria innocua in meat.an immunomagnetic immunofluorescent method was investigated for the rapid detection of listeria monocytogenes and listeria innouca. this technique involved enrichment of the suspect sample at 30 degrees c overnight. listeria monocytogenes cells were isolated from the enriched sample using immunomagnetic separation and listeria were subsequently visualized using an immunofluorescent microscopy technique. this technique was used in the detection of listeria cells from pure culture, inoculated beef ...19979203399
profilin interacts with the gly-pro-pro-pro-pro-pro sequences of vasodilator-stimulated phosphoprotein (vasp): implications for actin-based listeria motility.intracellular actin-based motility of listeria monocytogenes requires protein-protein interactions involving two different proline-rich sequences: first, the tightly bound bacterial surface protein acta uses its multiple oligoproline registers [consensus sequence = fe(d)fpppptd(e)e(d)] to tether vasodilator-stimulated phosphoprotein (vasp) to the bacterial surface; and second, vasp then deploys its own multiple gppppp (or gp5) registers to localize the actin-regulatory protein profilin to promot ...19979204886
mr monitoring of a medically treated spinal cord abscess presumptively due to listeria monocytogenes. 19979208269
tap-dependent major histocompatibility complex class i presentation of soluble proteins using listeriolysin.immunization of mice with mixtures of listeriolysin, a pore-forming hemolysin secreted by the pathogenic bacterium listeria monocytogenes, together with soluble ovalbumin, nucleoprotein of influenza virus, or beta-galactosidase of escherichia coli, resulted in strong cytotoxic cd8 t cell responses to each of the respective passenger proteins in vivo. also, the concomitant addition of either protein with listeriolysin to target cells elicited efficient sensitization of these cells which could be ...19979209484
the defined attenuated listeria monocytogenes delta mp12 mutant is an effective oral vaccine carrier to trigger a long-lasting immune response against a mouse fibrosarcoma.listeria monocytogenes has been proposed as a carrier to elicit major histocompatibility complex class-i restricted immune responses able to protect against tumor challenge. in this study the properties of the attenuated l. monocytogenes delta mp12 mutant has been evaluated in vivo against a highly aggressive mouse fibrosarcoma which expresses beta-galactosidase (beta-gal) as a tumor-associated antigen (taa). immunization with the vaccine prototypes resulted in both elicitation of specific antib ...19979209512
the human lactobacillus acidophilus strain la1 secretes a nonbacteriocin antibacterial substance(s) active in vitro and in vivo.the adhering human lactobacillus acidophilus strain la1 inhibits the cell association and cell invasion of enteropathogens in cultured human intestinal caco-2 cells (m. f. bernet, d. brassard, j. r. neeser, and a. l. servin, gut 35:483-489, 1994). here, we demonstrate that strain la1 developed its antibacterial activity in conventional or germ-free mouse models orally infected by salmonella typhimurium. we present evidence that the spent culture supernatant of strain la1 (la1-scs) contained anti ...19979212421
investigation of a listeriosis epizootic in sheep in new york state.to investigate potential sources of an epizootic of listerial encephalitis, using molecular diagnostic and typing methods.19979215449
a heterogeneous population model for the analysis of bacterial growth kinetics.a two-compartment, heterogeneous population model (hpm) was derived using the simulation software sb modelmaker to describe the growth of listeria monocytogenes in bacteriological media at 5-35 degrees c. the model assumed that, at time t = 0, the inoculum was distributed between two distinct compartments, non-growing and growing, and that growth could be described by four parameters: initial total cell population (n0), final maximum cell population (nmax), maximum specific growth rate (mu(max)) ...19979217107
ligand recruitment by vinculin domains in transfected cells.vinculin, a prominent protein component of microfilament-membrane attachment sites, consists of three major domains: an n-terminal, compact head and a c-terminal rod-like tail that are connected by a flexible, proline-rich hinge. in vitro, the protein has been shown to interact with numerous ligands, including other components of the microfilament system. to characterize the ligand recruitment ability of the different vinculin domains in a cellular environment, we used a novel approach of compri ...19979217322
tnf-alpha-mediated expression of the receptor for anaphylatoxin c5a on neurons in experimental listeria meningoencephalitis.the anaphylatoxin c5a has been implicated in the pathogenesis of bacterial meningitis as a potent mediator of inflammation in the subarachnoid space. we investigated the expression of the receptor for c5a (c5ar) in brains of mice with experimental listeria monocytogenes (lm) meningoencephalitis. in the course of the disease, infiltrating cells in the meninges and the ventricles were found to express c5ar mrna and protein. in the brain parenchyma, very low constitutive c5ar expression was seen on ...19979218605
in-vitro activity of trovafloxacin against clinical bacterial isolates from patients with cancer.the antibacterial activity of trovafloxacin was compared with that of ciprofloxacin, levofloxacin, ofloxacin, sparfloxacin and norfloxacin against bacterial isolates from patients with cancer. in general, the activity of trovafloxacin was comparable to that of ciprofloxacin, levofloxacin and sparfloxacin against most gram-negative isolates tested (minor differences in the activity of each agent against individual species were seen) and it was the most active agent tested against stenotrophomonas ...19979222065
a re-pcr method to distinguish listeria monocytogenes serovars.strains (107) of l. monocytogenes were tested with a pcr-restriction enzyme analysis with two new original primers. a segment of 1395 bp containing the entire iap gene in l. monocytogenes was amplified by the pcr technique. the pcr product was cleaved with the restriction enzymes hindiii and rsai, and the fragments generated were separated by gel electrophoresis. two groups of serovars were obtained: one group contained serovars 1/2a and 1/2c, the other group contained serovars 1/2b, 3b and 4b. ...19979223613
antibodies to listeria monocytogenes.listeria monocytogenes is one of the leading foodborne pathogens and has been implicated in numerous outbreaks in the last 2 decades. immunocompromised populations are usually the most susceptible to listeria infections. although the pathogenic mechanism is a complex process, significant progress has been made in unravelling the mechanism in recent years. it is now clear that numerous extracellular and cell-associated proteins, such as internalin, listeriolysin, actin polymerization protein, pho ...19979226109
listeria monocytogenes: a rare cause of pleural effusion in a patient with congestive cardiac failure.we report the case of a 65 year old immunocompetent man with a listerial pleural effusion. infection of the pulmonary parenchyma and pleura with listeria monocytogenes has been reported in small numbers of immunocompromised patients but there have been only two previous reports of pulmonary listeria in non-compromised hosts.19979226774
inter- and intraspecies comparison of the 16s-23s rrna operon intergenic spacer regions of six listeria spp.the 16s-23s rrna intergenic spacer (igs) regions found in six listeria species were characterized. pcr amplification of the 16s-23s igs with a "generic primer" set generated products of about 340 bp (small) and 550 to 590 bp (large) with dna from all listeria strains tested. seven listeria monocytogenes serotype 4b strains and one l. monocytogenes serotype 4d strain also had an additional pcr product of ca. 360 bp. the 360-bp pcr product from one of these l. monocytogenes serotype 4b strains was ...19979226919
characterisation of the peptidoglycan hydrolases of listeria monocytogenes egd.the peptidoglycan hydrolase profile of listeria monocytogenes egd has been characterised under a variety of environmental and physiological conditions, using renaturing sodium dodecyl sulfate-polyacrylamide gel electrophoresis. the profiles show activities ranging from 29 to 186 kda. the 186-kda enzyme was only observable under specific medium and aeration conditions. the enzyme activities show differential substrate specificity and sensitivity to incubation conditions. the peptidoglycan hydrola ...19979228781
the human arp2/3 complex is composed of evolutionarily conserved subunits and is localized to cellular regions of dynamic actin filament assembly.the arp2/3 protein complex has been implicated in the control of actin polymerization in cells. the human complex consists of seven subunits which include the actin related proteins arp2 and arp3, and five others referred to as p41-arc, p34-arc, p21-arc, p20-arc, and p16-arc (p omplex). we have determined the predicted amino acid sequence of all seven subunits. each has homologues in diverse eukaryotes, implying that the structure and function of the complex has been conserved through evolution. ...19979230079
simple color tests based on an alanyl peptidase reaction which differentiate listeria monocytogenes from other listeria species.the hydrolysis of dl-alanine-beta-naphthylamide and d-alanine-p-nitroanilide for identification of listeria spp. has been studied with 227 cultures. all species of listeria, except l. monocytogenes, hydrolyzed these substrates. the reactions were detected by simple chromogenic reactions and could substitute for the camp test.19979230403
a fatal case of listeria endocarditis in a man following his tending of goats suggests an epidemiological link which is not supported by the results.a man died in endocarditis due to listeriosis in the late autumn. he had been looking after two goats during the summer. listeria monocytogenas was isolated from a rectal swab from one of the goats. the goat faeces isolate and the human blood isolate were of identical serovar. the two isolates, however, were shown to be different by multilocus electrophoretic enzyme analysis and ribotyping, as well as by biotyping. thus, these results do not support the hypothesis that the man was infected by th ...19979230676
expression of inducible nitric oxide synthase by macrophages in rat lung.nitric oxide (no) is a short-lived free radical that is secreted by pulmonary macrophages (mø). an inducible isoform of no synthase (inos) catalyses the production of no and is activated by lipopolysaccharide and certain t-helper(h) 1 cytokines, including interferon-gamma and tnf-alpha. in the present study, inos+ interstitial cells were demonstrated in the alveolar wall of normal lewis rat lung. enzymatic digests of normal lung showed that approximately one third of pulmonary ed1+ interstitial ...19979230752
effect of experimental infection with listeria monocytogenes on the development of pregnancy and on concentrations of progesterone, oestrone sulphate and 15-ketodihydro-pgf2 alpha in the goat.the effect of listeria monocytogenes infection on hormone levels in pregnant goats was studied. four goats (group i) received an intravenous inoculation of a bacterial culture (type 1) on days 69-77 and another four goats (group ii) received a similar inoculation on days 105-106 of gestation. five non-inoculated goats were used as controls. plasma was analysed for progesterone, oestrone sulphate and 15-ketodihydro-pgf2 alpha. the status of the foetus was followed using real-time ultrasonography. ...19979231241
t-cell anergy induced by antigen presenting cells treated with the hemolysin of listeria monocytogenes.antigen presenting cells (apc) that are infected with listeriolysin (llo) secreting listeria lack the ability to stimulate mhc class ii restricted t-cells by conventional antigens. similarly, t-cell activation by native proteins but not by peptides was inhibited upon pretreatment of apc with purified listeriolysin. the inhibition is due to an irreversible inactivation of t-cells that recognize antigen on infected or llo treated apc. inhibition was found to dominate over stimulation by peptides. ...19979232422
bacterial phospholipases. 19979234505
how the listeria monocytogenes acta protein converts actin polymerization into a motile force.the acta protein is an essential determinant of pathogenicity that is responsible for the actin-based motility of listeria monocytogenes in mammalian cells and cell-free extracts. acta appears to control at least four functions that collectively lead to actin-based motility: (1) initiation of actin polymerization, (2) polarization of acta function, (3) transformation of actin polymerization into a motile force and (4) acceleration of movement mediated by the host protein profilin.19979234509
ocular disease associated with silage feeding and listeria monocytogenes in fallow deer. 19979234555
multiple control elements mediate activation of the murine and human interleukin 12 p40 promoters: evidence of functional synergy between c/ebp and rel proteins.interleukin 12 (il-12) is a heterodimeric cytokine whose activity is critical for t-helper 1 responses. the gene for the il-12 p40 subunit is expressed in macrophages following induction by bacterial products, and its expression is augmented by gamma interferon. in this study, we performed a functional analysis of the murine and human p40 promoters in the murine macrophage cell line raw 264.7. transcription from the murine p40 promoter was strongly induced by lipopolysaccharide and heat-killed l ...19979234715
the listeria monocytogenes-secreted p60 protein is an n-end rule substrate in the cytosol of infected cells. implications for major histocompatibility complex class i antigen processing of bacterial proteins.cytosolic antigen degradation is an initial step in the generation of major histocompatibility complex (mhc) class i-associated cytolytic t lymphocyte epitopes. intracellular listeria monocytogenes secretes p60, a murein hydrolase, into the host cell cytosol, where it is degraded by proteasomes. roughly 3% of degraded p60 gives rise to p60 217-225, a nonamer peptide that is bound by h-2kd mhc class i molecules. herein, we introduce targeted deletions throughout the p60 gene to identify potential ...19979235920
rapid purification, partial characterization, and antimicrobial spectrum of the bacteriocin, pediocin acm, from pediococcus acidilactici m.the bacteriocin from pediococcus acidilactici m, designated as pediocin acm, was rapidly purified to homogeneity by the ph mediated cell adsorption-desorption method and semi-preparative reversed-phase hplc. the purification yield was 40.4% and the specific activity was increased by 2450-fold. it gave a single band and a single peak on sds-page and hplc analysis, respectively. when subjected to electrospray lc-ms analysis, the protein was found to be highly pure and the molecular weight was dete ...19979237116
predictive model of the effect of co2, ph, temperature and nacl on the growth of listeria monocytogenes.the growth responses of l. monocytogenes as affected by co2 concentration (0-100% v/v, balance nitrogen), nacl concentration (0.5-8.0% w/v), ph (4.5-7.0) and temperature (4-20 degrees c) were studied in laboratory medium. growth curves were fitted using the model of baranyi and roberts, and specific growth rates derived from the curve fit were modelled. predictions for specific growth rate, doubling time and time to a 1000-fold increase could be made for any combination of conditions within the ...19979237120
augmentation of host defence against bacterial and fungal infections of mice pretreated with the non-pathogenic escherichia coli strain nissle 1917.escherichia coli strain nissle 1917 (dsm 6601, mutaflor) was investigated for its ability to enhance the immune response against bacterial or fungal infections in vivo. mice were infected intravenously with either 6 x 10(3) colony forming units (cfu) of listeria monocytogenes bacteria or 5 x 10(5) candida albicans cells. one day prior to infection, mice were treated orally with four different concentrations of e. coli strain nissle 1917 (10(6), 10(7), 10(8), and 10(9) viable cells). three days a ...19979239462
isolation of catalase-negative listeria monocytogenes strains from listeriosis patients and their rapid identification by anti-p60 antibodies and/or pcr.two catalase-negative listeria monocytogenes serovar 1/2b strains were isolated from listeriosis patients in 1995 in germany. the infections appeared in individuals from different cities at different seasons and were caused by l. monocytogenes strains of different clonal types. in particular, the catalase reaction of one strain isolated from blood was consistently negative, whereas this reaction was only reversibly blocked when the strain was freshly isolated from ascitic fluid. after subculturi ...19978968903
requirement of the initial production of gamma interferon in the generation of protective immunity of mice against listeria monocytogenes.protective immunity of mice against listeria monocytogenes, which is mediated mainly by gamma interferon (ifn-gamma)-producing t cells, was induced by immunization with viable bacteria but not with killed bacteria. by comparing mice immunized with either viable or killed l. monocytogenes, it was found that ifn-gamma was produced at the initial stage only after immunization with viable bacteria. this finding prompted us to investigate the effect of neutralizing the ifn-gamma on the final generati ...19978975894
host cell heparan sulfate proteoglycans mediate attachment and entry of listeria monocytogenes, and the listerial surface protein acta is involved in heparan sulfate receptor recognition.the mechanisms by which the intracellular pathogen listeria monocytogenes interacts with the host cell surface remain largely unknown. in this study, we investigated the role of heparan sulfate proteoglycans (hspg) in listerial infection. pretreatment of bacteria with heparin or heparan sulfate (hs), but not with other glycosaminoglycans, inhibited attachment and subsequent uptake by ic-21 murine macrophages and cho epithelial-like cells. specific removal of hs from target cells with heparinase ...19978975895
Refresh
firstprev
...111112113114115116117118119120...
nextlast
Displaying items 11601 - 11700 of 16792