Publications

TitleAbstractYear
Filter
PMID(sorted descending)
Filter
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
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
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
identification of listeria species by a semi-nested polymerase chain reaction.three primers derived from the lap gene were used to distinguish listeria monocytogenes from l.innocua and other listeria species. l. monocytogenes and l. innocua yielded a pcr product of 600 and 300 bp, respectively, whereas a typical pattern of three amplimers was observed with l. ivanovii, l. seeligeri and l. welshimeri.19969157490
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
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
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
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 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
neonatal meningitis due to multi-resistant listeria monocytogenes. 19979145834
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
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
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
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
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
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
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
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
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
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
class ib mhc products in host immunity against listeria monocytogenes. 19969127884
enhanced intracellular dissociation of major histocompatibility complex class i-associated peptides: a mechanism for optimizing the spectrum of cell surface-presented cytotoxic t lymphocyte epitopes.association of antigenic peptides with newly synthesized major histocompatibility complex (mhc) class i molecules occurs in the endoplasmic reticulum and is a critical early step for the initiation of cytotoxic t lymphocyte (ctl)-mediated immune defenses. pathogen-derived peptides compete with a plethora of endogenous peptides for mhc class i grooves. we find that two h2-k(d)-restricted peptides, which derive from the listeria monocytogenes p60 antigen, accumulate in infected cells with differen ...19979126921
neutrophils and tumour necrosis factor-alpha are important for controlling early gastrointestinal stages of experimental murine listeriosis.the present study examined the need for neutrophils and tumour necrosis factor-alpha (tnf alpha) for early defence against gut infection with the enteroinvasive, facultative intracellular bacterial pathogen, listeria monocytogenes. mice were treated with a neutrophil-depleting monoclonal antibody (mab) or a mab directed against tnf alpha, and the consequences of these treatments on the course of orally initiated infection with the pathogen were monitored. by day 3, orally initiated l. monocytoge ...19979126825
cd95 (fas) may control the expansion of activated t cells after elimination of bacteria in murine listeriosis.cd95 (fas) is known to mediate activation-induced t-cell death by apoptosis. to understand the role of cd95 during the course of bacterial infection, we examined the kinetics of alphabeta and gammadelta t cells in the peritoneal cavities and livers of 5-week-old cd95-defective mrl/lpr mice after an intraperitoneal infection with listeria monocytogenes. the number of bacteria in the spleen decreased to an undetectable level by day 10 after infection with 7 x 10(3) listeria cells similar to the nu ...19979125576
identification of four new members of the internalin multigene family of listeria monocytogenes egd.listeria monocytogenes is a bacterial pathogen that is able to invade nonphagocytic cells. two surface proteins, internalin, the inla gene product, and inlb, play important roles in the entry into cultured mammalian cells. these proteins also have extensive sequence similarities. previously, southern hybridization predicted the existence of an internalin multigene family. recently, inlc, a secreted protein of 30 kda homologous to inla and inlb, was identified. in this work, we identified and cha ...19979125538
a review of listeria monocytogenes and listeriosis.following the initial isolation and description in 1926 listeria monocytogenes has been shown to be of world-wide prevalence and is associated with serious disease in a wide variety of animals, including man. our knowledge of this bacterial pathogen and the various forms of listeriosis that it causes has until recently been extremely limited, but recent advances in taxonomy, isolation methods, bacterial typing, molecular biology and cell biology have extended our knowledge. it is an exquisitely ...19979125353
animal and human listeriosis: a shared problem? 19979125351
membrane permeabilization by listeria monocytogenes phosphatidylinositol-specific phospholipase c is independent of phospholipid hydrolysis and cooperative with listeriolysin o. 19979122270
crucial role of interferon consensus sequence binding protein, but neither of interferon regulatory factor 1 nor of nitric oxide synthesis for protection against murine listeriosis.listeria monocytogenes is widely used as a model to study immune responses against intracellular bacteria. it has been shown that neutrophils and macrophages play an important role to restrict bacterial replication in the early phase of primary infection in mice, and that the cytokines interferon-gamma (ifn-gamma) and tumor necrosis factor-alpha (tnf-alpha) are essential for protection. however, the involved signaling pathways and effector mechanisms are still poorly understood. this study inves ...19979120398
immunodominant and subdominant ctl responses to listeria monocytogenes infection.protective immunity to infection by intracellular pathogens begins with expansion of ag-specific, effector t lymphocytes and is followed by persistence of pathogen-specific memory t cells. infection by listeria monocytogenes, an intracellular bacterium, induces cytolytic t lymphocytes that mediate systemic sterilization and long term immunity. in cells infected with l. monocytogenes, h2-kd class i molecules present three nonamer peptides, listeriolysin (llo) 91-99, p60 217-225, and p60 449-457, ...19979120295
molecular diagnostics for dairy-borne pathogens.advances in diagnostic assays based on nucleic acids will revolutionize the ability of the industry to maintain the safety of dairy foods. two complementary assay formats are explored, one of which permits the rapid detection of bacterial pathogens and the other the identification of reservoirs of these pathogens. the first format is an assay based on the polymerase chain reaction that employs homogeneous detection (taqman polymerase chain reaction detection; perkin elmer, applied biosystems div ...19979120093
evidence that prfa, the pleiotropic activator of virulence genes in listeria monocytogenes, can be present but inactive.all virulence genes of listeria monocytogenes identified to date are positively regulated by prfa, a transcriptional activator belonging to the crp-fnr family. low temperature and cellobiose are two environmental signals known to repress expression of virulence genes in l. monocytogenes. in the present work, we analyzed the effect of temperature and cellobiose on the expression of the prfa protein. at low temperature, prfa was undetected, although prfa monocistronic transcripts are present. in c ...19979119495
protection against murine listeriosis by an attenuated recombinant salmonella typhimurium vaccine strain that secretes the naturally somatic antigen superoxide dismutase.a recombinant (r)-salmonella typhimurium aroa vaccine strain was constructed which secretes the naturally somatic protein of listeria monocytogenes, superoxide dismutase (sod), by the hlyb/hlyd/tolc export machinery. vaccine efficacy of the sod-bearing carrier strain was compared with that of the p60-secreting construct, s. typhimurium p60s (j. hess, i. gentschev, d. miko, m. welzel, c. ladel, w. goebel, and s. h. e. kaufmann, proc. natl. acad. sci. usa 93:1458-1463, 1996). vaccination of mice w ...19979119463
the protective role of endogenous cytokines in host resistance against an intragastric infection with listeria monocytogenes in mice.it has been demonstrated that endogenous cytokines including gamma-interferon (ifn-gamma), tumour necrosis factor-alpha (tnf-alpha), and interleukin-6 (il-6) play a protective role but that il-4 plays a detrimental role in systemic listeria monocytogenes infection in mice. the diverse roles of il-10 have been reported in antilisterial resistance. in this paper, we studied the role of endogenous cytokines in host resistance against an intragastric infection with l. monocytogenes in mice. the expr ...19969116648
involvement of various combinations of endogenous inflammatory cytokines in listeria monocytogenes-induced expression of inducible nitric oxide synthase in mice.using a in vitro infection of spleen cells with listeria monocytogenes, the relationship between endogenous cytokines and the expression of inducible nitric oxide synthase (inos) was examined. when all interferon (ifn)-gamma, tumor necrosis factor (tnf)-alpha and interleukin (il)-1 alpha, or the combination of ifn-gamma with either tnf-alpha or il-1 alpha were neutralized by antibodies, there was a significant reduction of inos expression and nitrite production in culture. however, there was no ...19969116644
expression of listeriolysin o by intracellular listeria monocytogenes following infection of lipopolysaccharide-treated or untreated j774.1 macrophage-like cells.listeria monocytogenes replicates in a phagocytic cell following escape into the host cytoplasm. listeriolysin o, secreted by l. monocytogenes, which belongs to the thiol-activated hemolysin family, is known to play an important role in the escape of the bacterium into the host cytoplasm. in this study, we demonstrated that expression of listeriolysin o by infecting l. monocytogenes was lightly induced in j774.1 macrophage-like cells pretreated with lipopolysaccharide, although the growth of the ...19969116638
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
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
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
culture-negative listeriosis of the central nervous system diagnosed by detection of antibodies to listeriolysin o. 19979105851
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
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
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
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
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
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
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
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
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
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
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
accelerating on a treadmill: adf/cofilin promotes rapid actin filament turnover in the dynamic cytoskeleton. 19979087434
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
[listeria in plants: an experimental study of its colonization, numbers and variability].the possibility for listeria monocytogenes to penetrate into plants from the soil via the root system was experimentally proved. listeria were shown to continuously persist for 30 days (the term of observation) in the vegetative organs of wheat (roots, stems and leaves). the concentration of listeria was 10(9) cfu/g in the environment (soil extract) and the roots of wheat, 10(6)-10(7) cfu/g in stems, 10(8)-10(9) cfu/g in leaves. six days later the dissociation of colonies in the s-form into smal ...19969082711
[listeriosis in a rabbitry].an enzootic of listeriosis in a rabbitry is reported. listeria monocytogenes serotype 1/2a was isolated from the organs of a doe, which had died of septic metritits. from aborted fetuses of two other does listeria monocytogenes serotype 1/2b and 4b were cultured, respectively. in feed samples of the rabbitry listeria monocytogenes strains of the serotypes 1/2b and 4b besides the apathogenic listeria species listeria seeligeri and listeria innocua were detected. serological studies with agglutina ...19969081819
simple relationship between acid dissociation constant and minimal ph for microbial growth in laboratory medium.a simple relationship was observed in growth medium, between the dissociation constant (via the pka) of the acid used to control ph and the minimum ph at which salmonellae and escherichia coli initiate growth. from this new relationship, a simple method was proposed to predict the minimum growth ph for a given strain and different acid types. this method, illustrated on listeria monocytogenes, would merely require the knowledge of two minimum ph values, one for a strong acid (e.g. hydrochloric a ...19979081228
the aerobic growth of aeromonas hydrophila and listeria monocytogenes in broths and on pork.flasks of tryptic soy broth (tsb), unacidified (ph 7.2) or acidified with hcl or lactic acid to ph 6.3 or 5.5, and samples of sterile pork fat or muscle tissue, were inoculated with logarithmic phase cultures of a strain of aeromonas hydrophila or a strain of listeria monocytogenes. the broth cultures were incubated at temperatures between 0 and 25 degrees c, and growth rates were determined from optical density increases. the tissue samples were incubated at temperatures between -2.4 and 25.2 d ...19979081227
nucleotide sequence analysis of two virulence-associated genes in listeria monocytogenes serotype 1/2b and comparison with the same genes in other serotypes important in human disease.the nucleotide sequences of the hly and plca genes (encoding listeriolysin, a thiol-activated cytolysin and a non-specific phospholipase c, respectively) were determined for two strains of listeria monocytogenes serotype 1/2b. the deduced amino acid sequences for listeriolysin were identical for the two strains and identical to that of listeriolysin from serotype 4b. the two serotype 1/2b strains differed in one amino acid (histidine vs asparagine) in the deduced amino acid sequence for phosopho ...19979080692
carbon-source regulation of virulence gene expression in listeria monocytogenes.all known virulence genes of listeria monocytogenes are under positive regulation by the transcription factor prfa. previous work employing the l. monocytogenes strain nctc7973 suggested that the disaccharide cellobiose might serve as a specific "signature molecule' which functions to prevent activation of the prfa-controlled regulon in a soil environment. we have examined three other l. monocytogenes strains, 10403s, lo28 and egd, all commonly regarded as wild-type isolates, and find that nctc7 ...19979076743
development of a predictive model for growth of listeria monocytogenes in a skim milk medium and validation studies in a range of dairy products.a predictive model based on growth of listeria monocytogenes in milk is described. the main aim of this work was to generate a predictive model in milk acidified with lactic acid to mimic conditions found in a range of dairy products. a complete factorial design was employed to determine the effects of ph (4.5-7.5), temperature (3-35 degrees c) and salt concentration (0-8%) on growth of the organism. there were 210 design points and growth curves were individually fitted for the gompertz functio ...19969072528
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
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
[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
down-regulation of listeria monocytogenes-specific th1 cytokine response by treatment of mice with goat antibody to mouse igd.injection of goat anti-mouse igd antibody (g alpha m igd) to mice has been shown to induce polyclonal igg1 and ige production by b cells and il-4 production by goat ig-specific t cells. surface igd crosslinking also activates function of b cells as antigen presenting cells. although the g alpha m igd treatment is a well established system for regulation of immune response against antigens that bind to b cell receptor, we found that the g alpha m igd treatment also influences immune response agai ...19969061384
occurrence of listeria and listeriosis in hungary.listeriosis is a rare human disease in hungary. the number of cases is slowly increasing. only sporadic events have been observed but the occurrence of epidemic listeriosis may be supposed. the listeria monocytogenes (in abbreviation: l. m.) transmitter role of food in human infections has not yet been verified. the epidemiological character of animal listeriosis is different. healthy carriers can be found among both humans and animals. foodstuffs of animal as well as plant origin may be contami ...19969055453
protamine-induced permeabilization of cell envelopes of gram-positive and gram-negative bacteria.the inhibitory effect of the cationic peptide protamine on listeria monocytogenes, escherichia coli, and shewanella putrefaciens has been studied in detail. the addition of protamine (10 to 1,000 micrograms/ml) resulted in inhibition of oxygen consumption after less than 1 min and loss of intracellular carboxyfluorescein and atp after 2 to 5 min. maximum antibacterial activity was reached at alkaline ph and in the absence of divalent cations. the efficient permeabilization of cell envelopes of b ...19979055431
dna fragments from regions involved in surface antigen expression specifically identify listeria monocytogenes serovar 4 and a subset thereof: cluster iib (serotypes 4b, 4d, and 4e).listeria monocytogenes serotype 4b has frequently been implicated in sporadic as well as epidemic listeriosis. on the basis of pulsed-field fingerprinting, serotype 4b strains, along with strains of serotypes 4d and 4e, constitute one genomic cluster (iib). we have identified two genomic regions essential for the expression of surface antigens which previously were shown to be specific to cluster iib strains. a dna probe of 1.1 kb derived from one of the regions (probe 1) hybridized only with st ...19979055423
abscess formation in listeria monocytogenes-infected gamma delta t cell deficient mouse mutants involves alpha beta t cells.although mutant mice lacking gamma delta t cells resolve listeria monocytogenes infection, extensive abscesses are formed. manifestation of these inflammatory lesions is prevented by in vivo depletion with monoclonal antibodies of cd4, cd8 or both t cell subsets. we conclude that these inflammatory tissue reactions develop when alpha beta t cells of either cd4 or cd8 phenotype are released from control by gamma delta t cells.19979050001
involvement of inflammatory cytokines and nitric oxide in the expression of non-specific resistance to listeria monocytogenes in mice induced by viable but not killed mycobacterium bovis bcg.the non-specific defense against listeria monocytogenes could be induced by viable bcg but not by killed bcg in mice. in order to understand the mechanism of antilisterial activity, viable and killed bcg were compared for their ability of inducing cytokine gene expression in spleen cells. both viable and killed bcg induced the same level of mrna expression of interleukin 10 (il-10), transforming growth factor beta (tgf-beta), il-12 and tumor necrosis factor alpha (tnf-alpha). gene expression and ...19979049997
mutants in the ctpa copper transporting p-type atpase reduce virulence of listeria monocytogenes.the ctpa protein from pathogenic listeria monocytogenes, is a p-type adenosine triphosphatase involved in copper homeostasis. to establish a role in pathogenicity for ctpa, a mutant strain was constructed by insertion of an antibiotic resistance cartridge into the ctpa gene. this mutant was then compared to the wild-type in tissue culture invasion assays and mouse infection studies. mutants in ctpa, were unaltered for intracellular growth in j774 and hela cell lines. however, recovery of mutants ...19979049996
acute bacterial meningitis in adults. a 20-year overview.most clinical overviews of acute bacterial meningitis have either focused on children or all age groups combined, although the disease poses serious problems in the adult population.19979046894
a gly145ser substitution in the transcriptional activator prfa causes constitutive overexpression of virulence factors in listeria monocytogenes.virulence genes in listeria monocytogenes are coordinately expressed under the control of the transcriptional activator prfa, encoded by prfa, a member of the cyclic amp (camp) receptor protein (crp)/fnr family of bacterial regulators. strain p14-a is a spontaneous mutant of l. monocytogenes serovar 4b which produces elevated levels of virulence factors (m. t. ripio, g. domínguez-bernal, m. suárez, k. brehm, p. berche, and j. a. vázquez-boland, res. microbiol. 147:371-384, 1996). here we report ...19979045810
transfer of phagocytosed particles to the parasitophorous vacuole of leishmania mexicana is a transient phenomenon preceding the acquisition of annexin i by the phagosome.the eukaryotic intracellular pathogen leishmania mexicana resides inside macrophages contained within a membrane bound parasitophorous vacuole which, as it matures, acquires the characteristics of a late endosomal compartment. this study reports the selectivity of fusion of this compartment with other particle containing vacuoles. phagosomes containing zymosan or live listeria monocytogenes rapidly fused with l. mexicana parasitophorous vacuoles, while those containing latex beads or heat killed ...19979044049
active catabolism of glucocorticoids by 11 beta-hydroxysteroid dehydrogenase in vivo is a necessary requirement for natural resistance to infection with listeria monocytogenes.the results from the present study demonstrate that the innate defense mechanisms which control the progressive growth of listeria monocytogenes in normal animals in vivo are dependent upon the active catabolism of endogenous glucocorticoids by the enzyme 11 beta-hydroxysteroid dehydrogenase (11 beta-hsd). when 11 beta-hsd activity was pharmacologically inhibited in vivo, host susceptibility to progressive bacterial disease was markedly increased. depressed natural resistance following 11 beta-h ...19979043952
effect of hot water extract of chlorella vulgaris on cytokine expression patterns in mice with murine acquired immunodeficiency syndrome after infection with listeria monocytogenes.we have previously reported that oral administration of hot water extract of chlorella vulgaris (cve) enhances resistance to listeria monocytogenes through augmentation of listeria-specific cell-mediated immunity in normal mice and mice with murine acquired immunodeficiency syndrome (maids) caused by murine leukemia virus (mulv) lp-bm5. to elucidate the mechanisms whereby cve augments the cell-mediated immunity, we examined the expression patterns of mrna for cytokines in normal and maids mice g ...19979043941
effect of dietary flaxseed on fatty acid composition, superoxide, nitric oxide generation and antilisterial activity of peritoneal macrophages from female sprague-dawley rats.the impact of ground flaxseed (fs) or flaxseed meal (fsm) diets on the fatty acid composition and functions of rat peritoneal exudate cells (pec) was determined. female weanling sprague-dawley rats (10/group) were fed isocaloric ain-76 diets supplemented with 0.0, 10.0% (w/w) fs or 6.2% (w/w) fsm. at the end of 56-days, rat serum and thioglycollate-elicited pec were analyzed for total lipid fatty acids. production of nitric oxide (no) and superoxide (o2-), listeria monocytogenes (lm) phagocytic ...19979042389
grand entry for listeria. 19979041273
inter-relationship among macrophages, natural killer cells and neutrophils in early stages of listeria resistance.reports in the past few years have shown the involvement of different cells and cytokines in controlling the infection with the intracellular facultative pathogen listeria monocytogenes. a synergistic interaction of t-cell-independent and -dependent processes takes place but the nature of these interactions and of the relevant cells and cytokines depends on both the stage of the infection and the tissue that is involved.19979039774
differences in pathogenicity for chick embryos and growth kinetics at 37 degrees c between clinical and meat isolates of listeria monocytogenes previously stored at 4 degrees c.fifteen clinical strains of listeria monocytogenes (eight strains of serogroup 4 and seven strains of serogroup 1) and 15 meat isolates (all serogroup 1) were stored with no growth in phosphate-buffered saline (ph 7.0) at 4 degrees c for 4 weeks. pathogenicity for 14 day old chick embryos and growth kinetics in brain heart infusion (bhi) broth at 37 degrees c of the strains were determined before and after storage. although no differences in pathogenicity between clinical and meat strains were f ...19979039576
predictive modelling of growth of listeria monocytogenes. the effects on growth of nacl, ph, storage temperature and nano2.the effect of nacl concentration (5.0 115.0 g/l). ph value (4.0-7.2), temperature (1-35 degrees c) and nano2 concentration (0 200 mg/l) on the growth responses of listeria monocytogenes, in laboratory medium was investigated. the growth curves generated within this matrix of conditions were fitted using the function of baranyi and roberts (1994) and the growth responses modelled using a quadratic polynomial to produce response surfaces. growth curves could then be regenerated for any set of cond ...19979039568
infection and removal of l-forms of listeria monocytogenes with bred bacteriophage.phage breeding was employed to produce a bacteriophage (listeria monocytogenes phage atcc 23074-b1) which was specific for l-forms of l. monocytogenes. the bred phage was compared to its unbred parent for lytic activity and specificity. it was also tested for its ability to prevent l-form biofilm formation on stainless steel and compared with an organic acid (lactic) at l-form biofilm inactivation on stainless steel. the bred phage lysed only l-forms of l. monocytogenes in broth culture and only ...19979039566
temperature distribution and prevalence of listeria spp. in domestic, retail and industrial refrigerators in greece.the present paper examined the presence of listeria spp. in the environment of domestic, retail and industrial refrigerators. from 136 household refrigerators, 136 surface samples were taken from the walls or shelves, and 125 from cheese compartments. only two refrigerators harboured l. monocytogenes. from 228 food store refrigerators, 335 samples were taken. of these, 118 were in in contact with cheeses, 69 with sausages, 21 with cheese and sausages, 20 with miscellaneous products and 107 from ...19979039563
insufficient antilisterial capacity of low inoculum lactobacillus cultures on long-term stored meats at 4 degrees c.two of the 210 lactobacilli strains isolated from chilled meats produced antilisterial bacteriocins: lactobacillus sake 265 (lb 265) and lactobacillus casei 52 (lb 52). factors affecting antilisterial effectiveness of these and two other bacteriocin-producing (bac+) strains (lactobacillus sake 706, lb 706; and lactobacillus sake 148, lb 148) at refrigeration temperature (4 degrees c) were studied in laboratory media and meat systems. at both 4 degrees c and 25 degrees c, these bac+ strains grown ...19979039562
dietary fish oil reduces survival and impairs bacterial clearance in c3h/hen mice challenged with listeria monocytogenes.1. to investigate the effect of dietary fat source on host resistance to intracellular pathogens, weanling female c3h/hen mice were fed one of three experimental diets containing, 20% by weight, lard, soybean oil or 17% menhaden fish oil plus 3% corn oil. after 4 weeks, survival of mice (n = 12/treatment group) injected intraperitoneally with 2 x 10(6) colony forming units of live listeria monocytogenes was determined. in a second study, bacterial clearance from the liver and spleen at 2, 4 and ...19979038598
involvement of tubulin and inhibitory g proteins in the interaction of listeria monocytogenes with mouse hepatocytes.intracellular and cell-to-cell spread of listeria monocytogenes has been considered exclusively actin dependent. by immunocytochemical techniques, we provide evidence for an involvement of inhibitory g proteins and tubulin in "comet tail" formation in l. monocytogenes-infected mouse hepatocytes.19979038321
elimination of resident macrophages from the livers and spleens of immune mice impairs acquired resistance against a secondary listeria monocytogenes infection.during a secondary listeria monocytogenes infection in mice, the bacteria are eliminated more rapidly from the liver and spleen than during a primary infection. this acquired resistance against a secondary infection is dependent on t lymphocytes, which induce enhanced elimination of bacteria via stimulation of effector cells such as neutrophils, resident macrophages, exudate macrophages, and hepatocytes. the aim of the present study was to determine the role of the resident macrophages in acquir ...19979038307
porcine polymorphonuclear leukocytes generate extracellular microbicidal activity by elastase-mediated activation of secreted proprotegrins.antimicrobial peptides of several structural classes have been found in phagocytes and epithelial cells of many animals. the broadly microbicidal protegrins (pg1, -2, and -3) were originally isolated as 16 to 18-amino-acid peptides from pig neutrophil lysates, but the corresponding cdna sequences encoded much larger precursors that belonged to the cathelicidin family of antimicrobial peptides. we explored the storage, secretion, and microbicidal activation of protegrins in porcine neutrophils an ...19979038306
effect of yersinia pestis yopm on experimental plague.yopm of yersinia pestis has previously been shown to be necessary for full virulence in mice and to be able to bind human alpha-thrombin. this activity prompted the hypothesis that yopm, functioning extracellularly during plague, might be accessible to neutralization by antibody and hence might be a protective antigen. this study tested this hypothesis and found that yopm was not protective, either by passive or active immunization, in inbred or outbred mice. these findings showed that either yo ...19979038298
effect of sampling procedure and strain variation in listeria monocytogenes on the discrimination of species in the genus listeria by fourier transform infrared spectroscopy and canonical variates analysis.the ability to discriminate successfully among cultures of all species of the listeria genus by infrared spectroscopy in combination with canonical variate analysis was confirmed. the robustness of the method was demonstrated by showing that the separation of l. monocytogenes and l. grayi was hardly affected by variations in broth medium, incubation temperature, incubation time and cell washing procedure. discrimination among 24 strains of l. monocytogenes according to serotype allowed two group ...19979037762
the listeria monocytogenes gene ctpa encodes a putative p-type atpase involved in copper transport.a tn917 transposon derivative was used to construct a lacz transcriptional fusion mutant in listeria monocytogenes drdc8 that displayed increased beta-galactosidase activity in response to cation stress. a 4.3 kb fragment of l. monocytogenes chromosomal dna flanking the lacz fusion was cloned and sequenced. a 1962 bp open reading frame was identified, and designated ctpa. analysis of the deduced 653 amino acid sequence revealed significant similarity to the family of atp-dependent enzymes involv ...19979037109
both innate and acquired immunity to listeria monocytogenes infection are increased in il-10-deficient mice.il-10-deficient mice were highly resistant to listeria monocytogenes during the course of infection. an increased innate immunity was suggested by reduced bacterial burdens (as much as 50-fold) early (days 2 and 3) in the infection, as compared with control mice. in addition, in vitro stimulation of both il-10-deficient peritoneal exudate cells and spleen cells with heat-killed listeria resulted in a dramatically enhanced proinflammatory cytokine response (e.g., il-12, ifn-gamma, tnf-alpha, il-1 ...19979036973
[central nervous system infections in patients with malignant diseases].infections of the nervous system remain a significant source of morbidity and mortality in patients with cancer. this paper reviews the main pathogens and emphasizes some of the principles of diagnosis and management of nervous system infections in cancer patients. due to immunosuppression, diagnosis is more difficult in this group, secondary to the multitude of potential pathogens, and often by their atypical presentations. fever or headache are often the only symptoms. clinical history and gen ...19969033951
catalase-negative listeria monocytogenes causing lethal sepsis and meningitis in an adult hematologic patient. 19969031886
bovine mastitis caused by listeria monocytogenes: kinetics of antibody responses in serum and milk after experimental infection.the kinetics of antibodies in serum and milk directed against proteins from listeria monocytogenes were studied using 4 lactating cows after infection was experimentally induced in the udder with four strains of serotypes 4b or 1/2a. antibodies (igg and iga) in samples of composite quarter milk and serum of the cow were measured by indirect elisa. microtiter plates were coated with proteins obtained from the culture supernatant of l. monocytogenes 4b. after challenge, an igg response in serum an ...19969029357
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
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
listeria monocytogenes scott a transports glucose by high-affinity and low-affinity glucose transport systems.listeria monocytogenes transported glucose by a high-affinity phosphoenolpyruvate-dependent phosphotransferase system and a low-affinity proton motive force-mediated system. the low-affinity system (km = 2.9 mm) was inhibited by 2-deoxyglucose and 6-deoxyglucose, whereas the high-affinity system (km = 0.11 mm) was inhibited by 2-deoxyglucose and mannose but not 6-deoxyglucose. cells and vesicles artificially energized with valinomycin transported glucose or 2-deoxyglucose at rates greater than t ...19979023935
functional characterization of pediocin pa-1 binding to liposomes in the absence of a protein receptor and its relationship to a predicted tertiary structure.the physicochemical interaction of pediocin pa-1 with target membranes was characterized using lipid vesicles made from the total lipids extracted from listeria monocytogenes. pediocin pa-1 caused the time- and concentration-dependent release of entrapped carboxyfluorescein (cf) from the vesicles. the pediocin-induced cf efflux rates were higher under acidic conditions than under neutral and alkaline conditions and were dependent on both pediocin and lipid concentrations. a binding isotherm cons ...19979023932
[acute bacterial meningitis in adults]. 19969019208
th0-like cd4+ t cells protect mice with murine retrovirus-induced immunodeficiency syndrome (maids) against co-infection with listeria monocytogenes.we examined the host defence mechanism against infection with listeria monocytogenes, a facultative intracellular bacterium, in mice with murine acquired immunodeficiency syndrome (maids) caused by lp-bm5 murine leukaemia virus (mulv) infection. although lp-bm5 mulv infection in c57bl/6 mice leads to a stage of immunodeficiency characterized by severe compromise of cell-mediated immunity, the mice with established maids infected with lp-bm5 8 weeks previously, showed resistance to an intraperito ...19969014817
Refresh
firstprev
...121122123124125126127128129130...
nextlast
Displaying items 12001 - 12100 of 16792