Publications

production of nisin-like bacteriocins by lactococcus lactis strains isolated from vegetables.	four bacteriocin producing lactic acid bacteria isolated from vegetables were identified as lactococcus lactis strains on the basis of physiological and biochemical characteristics, carbohydrate fermentation patterns and analysis of total soluble protein pattern by sds page. the bacteriocins had a wide spectrum of activity as antagonism was detected not only towards a variety of lactic acid bacteria, but also to staphylococcus aureus and listeria monocytogenes. these bacteriocins were resistant ...	1997	9265741
gastroenteritis caused by listeria monocytogenes in a private day-care facility.		1997	9271054
spatial interactions between subsurface bacterial colonies in a model system: a territory model describing the inhibition of listeria monocytogenes by a nisin-producing lactic acid bacterium.	the effect of spatial separation on interactions between subsurface bacterial colonies was tested using a model system: the inhibition of listeria monocytogenes by nisin-producing and nisin-non-producing lactococcus lactis subsp. lactis. separation distance was controlled by altering the number of inoculum organisms within the agar. mean separation distance was calculated by determining the mean volume available to each cell at the start of the experiment. inhibition was assessed by comparing th ...	1997	9274011
comparative sensitivity of 13 species of pathogenic bacteria to seven chemical germicides.	the relative resistance of diverse human bacterial pathogens to commonly used germicidal agents has not been established.	1997	9276546
safe poultry meat production in the next century.	the revolutionary industrialisation of the poultry industry in the last 30 years has made the food poultry meat available for large groups of consumers. due to its nutritional, sensory and economical characteristics, poultry meat is by far the most popular animal food product world-wide. epidemiological reports, however, incriminate poultry meat as a source for outbreaks of human food poisoning. the organisms involved are salmonella spp., campylobacter spp. and, to a lesser extent, listeria mono ...	1997	9276991
[escape mechanism of listeria monocytogenes in relation to host immune response].		1997	9277105
absence of il-1 signaling and reduced inflammatory response in il-1 type i receptor-deficient mice.	il-1alpha and il-1beta are potent inflammatory cytokines that contribute to a number of normal physiologic processes and to the development of a number of inflammatory diseases. two il-1r, the type i and type ii receptors, have been identified. this work describes the derivation and characterization of mice deficient in expression of the type i il-1r (il-1ri). il-1ri-deficient mice were viable and fertile, but failed to respond to il-1 in a variety of assays, including il-1-induced il-6 and e-se ...	1997	9278338
the effect of high hydrostatic pressure on listeria monocytogenes in phosphate-buffered saline and model food systems.	three strains of listeria monocytogenes (nctc 1194, a poultry isolate and the scott a strain) were exposed to a range of pressures (300, 350, 375, 400 and 450 mpa) in 10 mmol 1(-1) phosphate-buffered saline (pbs) at ph 7.0 for up to 30 min at ambient temperature. generally, increasing the magnitude and duration of compression resulted in increasing levels of inactivation, although the inactivation kinetics varied depending on the strain and pressure applied. the three strains also exhibited a wi ...	1997	9281822
economic costs and trade impacts of microbial foodborne illness.	this article presents the economic costs of foodborne diseases for selected countries, the approaches used to calculate these costs, and a discussion on the interaction between microbial food safety issues and international trade in food. the human illness costs due to foodborne pathogens are estimated most completely in the united states of america, where, each year, 7 foodborne pathogens (campylobacter jejuni, clostridium perfringens, escherichia coli o157:h7. listeria monocytogenes, salmonell ...	1997	9282387
foodborne listeriosis.	various epidemiological investigations of outbreaks and sporadic cases have clearly demonstrated that the consumption of contaminated food is responsible for a high proportion of listeriosis cases and listeria monocytogenes has been increasingly recognized as an important foodborne pathogen over the last 15 years. the emergence of listeriosis is the result of complex interactions of different factors: medical progress which increases the lifespan and allows immunodeficient people to survive, exp ...	1997	9282388
inlb: an invasion protein of listeria monocytogenes with a novel type of surface association.	listeria monocytogenes is an intracellular bacterial pathogen that expresses several surface proteins critical for the infectious process. such proteins include inla (internalin) and inlb, involved in bacterial entry into the host cell, and acta, required for bacterially induced actin-based motility. although the molecular mechanisms of attachment of inla and acta have been characterized, essentially nothing is known about how inlb is anchored to the bacterial surface. using a genetic approach, ...	1997	9282740
listeriolysin and irpa are major protein targets of the human humoral response against listeria monocytogenes.	we have examined the human humoral immune response directed against proteins of listeria monocytogenes in both healthy individuals and listeriosis patients. two major targets for an antibody response were found in individuals that did not suffer from listeriosis: listeriolysin (hly) and the recently described internalin-related protein (irpa). in contrast, the humoral response in listeriosis patients appears to be more heterogeneous and included hly, irpa, inlb, and acta as major targets.	1997	9284184
lymphocyte apoptosis during early phase of listeria infection in mice.	during the acute phase of growth of listeria monocytogenes in spleen and lymph nodes, the infective foci consist of macrophages and neutrophils accompanied by extensive death of lymphocytes. many of the lymphocytes die by apoptosis. the lesions are found by 48 hours after infection and can regress with time. depending on the dose, the infected foci can be restricted to the thymus-dependent areas or can occupy the entire lymphoid tissue. the listeria in the lesions are primarily found inside macr ...	1997	9284827
alternative antigen processing pathways in anti-infective immunity.	proteinaceous and nonproteinaceous antigens from exogenous microorganisms can be processed by the host for mhc class i restricted presentation to t cells. macrophages, b cells, mast cells and dendritic cells are antigen-presenting cells that process such exogenous antigens through multiple pathways before mhc-restricted epitope presentation. new conceptual frameworks are emerging regarding the processing and presentation to t cells of peptide or nonpeptide epitopes from bacteria in the context o ...	1997	9287179
evaluation of seven experimental phages for inclusion in the international phage set for the epidemiological typing of listeria monocytogenes.	the purpose of our study was to evaluate the inclusion of seven experimental phages into the international phage set for subtyping listeria monocytogenes. the seven additional phages included the broad-host-range virulent myoviridae phage a511 (m. j. loessner, appl. environ. microbiol. 57:1912-1918, 1991), three temperate phages from the danish subsystem for typing serotype 1/2 strains (12682, 6223, and 5775) (p. gerner-smidt, v.t. rosdahl, and w. frederiksen, apmis 101:160-167, 1993), and three ...	1997	9292987
modifications of membrane phospholipid composition in nisin-resistant listeria monocytogenes scott a.	a nisin-resistant (nisr) variant of listeria monocytogenes scott a was isolated by stepwise exposure to increasing concentrations of nisin in brain heart infusion (bhi) broth. the nisr strain was about 12 times more resistant to nisin than was the wild-type (wt) strain. accordingly, higher nisin concentrations were required to dissipate both components of the proton motive force in the nisr strain than in the wt strain. comparison of the membrane fatty acyl composition of the sensitive strain wi ...	1997	9292996
construction of the temperature-sensitive vectors pluch80 and pluch88 for delivery of tn917::noti/smai and use of these vectors to derive a circular map of listeria monocytogenes scott a, a serotype 4b isolate.	a physical map of listeria monocytogenes scott a was generated by the pulsed-field technique of contour-clamped-homogeneous-electric-field (chef) electrophoresis. the circular genome of this serotype 4b strain contains 12 asci fragments (38 to 790 kb), 5 noti fragments (55 to 1,400 kb), 3 srfi fragments (110, 1,110, and 2,000 kb), and 2 sfii fragments (1,320 and 1,920 kb). summation of individually sized fragments derived by digestion of scott a genomic dna with each of these four enzymes provid ...	1997	9292998
effects of ph on distribution of listeria ribotypes in corn, hay, and grass silage.	listeria app, isolated from 13 of 129 (10%) corn silage samples, 21 of 76 (28%) hay silage samples, and 3 of 5 (60%) grass silage samples during a previous vermont survey were subjected to automated ribotype (rt) analysis. the 13 positive corn silage samples contained 3 listeria monocytogenes isolated (three rts, including one known clinical rt) and 10 l. innocua isolates (four rts). similarly, 2 l. monocytogenes isolates (two rts) and 19 l. innocua isolates (three rts) were identified in the 21 ...	1997	9293020
acta is a dimer.	acta, a surface protein of listeria monocytogenes, is able to induce continuous actin polymerization at the rear of the bacterium, in the cytosol of the infected cells. its n-terminal domain is sufficient to induce actin tail formation and movement. here, we demonstrate, using the yeast two-hybrid system, that the n-terminal domain of acta may form homodimers. by using chemical cross-linking to explore the possibility that acta could be a multimer on the surface of the bacteria, we show that act ...	1997	9294158
[cerebral listeriosis in cattle: literature review and retrospective analysis of individual cases].	between 1990 and 1994, 89 cattle with signs of affection of the central nervous system were referred to the clinic for food animals and horses, university of bern; in 17 cases of which, cerebral listeriosis was diagnosed. history, clinical, hematologic findings and cerebrospinal fluid analysis at admission were evaluated retrospectively. four cattle were slaughtered after cerebral listeriosis had been diagnosed clinically because of economic reasons. therapy, consisting of administration of peni ...	1997	9312892
studies in listeriosis show the strong symbiosis between the innate cellular system and the t-cell response.	resistance to infection with listeria monocytogenes involves a series of cellular interactions, many of which are carried out by cytokines. macrophages, nk cells and neutrophils participate in early stages of listeria resistance. the neutrophil is specially important for clearance of the liver phase of listeriosis. macrophages and nk cells interact by way of il-12 and tnf, which induce the nk cell to produce ifn-gamma. ifn-gamma is the major macrophage-activating cytokine. the cb-17 scid mouse s ...	1997	9314070
murine listeriosis as a model of antimicrobial defense.	murine listeriosis was introduced 35 years ago as a model with which to analyze mechanisms of antibacterial defense that are independent of antibodies. listeria monocytogenes was shown to be an intramacrophage pathogen with capacity to induce the generation of a state of specific immunity in the form of dth and a macrophage system with enhanced non-specific bactericidal activity. the demonstration that anti-listeria immunity and dth can be passively transferred with t cells was taken to indicate ...	1997	9314071
listeria monocytogenes in laboratory mice: a model of short-term infectious and pathogenic processes controllable by regulated protective immune responses.	the mammalian immune system is an integrated network of tissue, leukocytes and effector and regulatory molecules. all these components operate i) to maintain the proper structure of and processes expressed by each tissue. and ii) to protect the hosts from those microorganisms that generally invade them as part of their life cycle. among the invading microorganisms. listeria monocytogenes (l. monocytogenes) can persist as a live organism independent of the host, and is, thus, able to drive short- ...	1997	9314072
non-specific resistance mechanisms to listeriosis: implications for experimental and naturally occurring infection.	use of murine listeriosis as an experimental model has greatly increased our understanding of the complex interplay of cells and mediators in non-specific antibacterial resistance (innate immunity). important contributions made with this experimental model include demonstrating the ability of inflammatory cytokines (i.e. ifn-gamma, il-1 alpha, tnf-alpha) to protect against bacterial infection, and illustrating the rapidity of the host cytokine response (detectable within 1 h of challenge) during ...	1997	9314073
responses by murine macrophages infected with listeria monocytogenes crucial for the development of immunity to this pathogen.	macrophages and other mammalian cells respond to infection with listeria monocytogenes (l. monocytogenes) by the transient or persistent activation of host cell signal transduction pathways. in addition, l. monocytogenes infection influences expression of various host cell genes, such as stress genes, genes from the mhc i and ii complex, cytokine genes, and cytokine receptor genes. the possible influences of the different host cell responses on the outcome of an l. monocytogenes infection in vit ...	1997	9314074
some macrophages kill listeria monocytogenes while others do not.	it is not known why some macrophages can kill certain microbes, such as the facultative intracellular bacterium listeria monocytogenes (l. monocytogenes), while other macrophages cannot. perhaps listericidal activity is a property of macrophages at specific stages of differentiation; may be the ability to kill this bacterium is regulated by the microenvironment of the cell: or it is possible that other regulatory forces are important. we describe here three characteristics that distinguish macro ...	1997	9314075
cytokines in the induction and expression of t-cell-mediated granuloma formation and protection in the murine model of listeriosis.	lymphocyte-mediated inflammation is a hallmark of autoimmune diseases, such as multiple sclerosis. crohn's disease, rheumatoid arthritis and sarcoidosis. however, this type of inflammation probably developed under evolutionary pressure from pathogenic microorganisms, such as mycobacteria and other intracellular infective agents. one such pathogen, the gram-positive bacterium listeria monocytogenes (l. monocytogenes), induces a cascade of tissue alterations that ultimately results in the eradicat ...	1997	9314076
interleukin-4 and listeriosis.	experimental infection of mice with listeria monocytogenes (l. monocytogenes) has served as an appropriate model for analyzing th1-cell-driven immune responses. generally, th2 responses are absent and il-4 is not detectable. here, we describe experimental settings under which il-4 is detectable in listeriosis. our data suggest that il-4 is rapidly produced after infection. this prompt il-4 burst seems to stimulate chemokine responses and, therefore, may participate in the regulation of the early ...	1997	9314077
the cytokine stew and innate resistance to l. monocytogenes.	the listeria monocytogenes (l. monocytogenes) infection model has been a useful system to evaluate the cellular interactions leading to host immunity. the initiation of the innate immune response in naive animals and subsequent progression to acquired immunity represent an integrated system with numerous layers of complexity. coincident with experimental infection is the induction of cytokines. cytokines, which are soluble mediators of cell growth, maintenance and function, from a network of ple ...	1997	9314078
ctl responses to h2-m3-restricted listeria epitopes.	cytotoxic t cells (ctl) play a critical role in the murine immune response to listeria monocytogenes (listeria). bacterial antigens are presented to listeria-specific ctl by products of both conventional, polymorphic mhc class ia and non-polymorphic mhc class ib alleles. the h2-m3 class ib gene product, m3, preferentially presents formylmethionine-initiating (fmet) peptides derived from the n termini of bacterial and mitochondrial proteins. thus, m3 signals the presence of bacterial invaders to ...	1997	9314079
characterization of the murine h2-m3wt-restricted cd8 response against a hydrophobic, protease-resistant, phospholipid-associated antigen from listeria monocytogenes.	mice infected with listeria monocytogenes (lm) generate protective cd8 cells of varying specificity. one subset, unlike conventional lm-immune cd8 cells, can respond to antigen-presenting cells (apc) treated with heat-killed lm (hklm). these cells proved to have surprisingly uniform specificity, recognizing a product we designated hklm-associated antigen (haa) presented by the non-classical class ib product h2-m3wt. haa proved to be extremely hydrophobic and the bioactive portion of the molecule ...	1997	9314080
mhc class i antigen processing of listeria monocytogenes proteins: implications for dominant and subdominant ctl responses.	listeria monocytogenes (l. monocytogenes) secretes proteins associated with its virulence into the cytosol of infected cells. these secreted proteins are degraded by host cell proteasomes and processed into peptides that are bound by mhc class i molecules in the endoplasmic reticulum. we have found that the mhc class i antigen-processing pathway is very efficient at generating the epitopes that are presented to cytolytic t lymphocytes (ctl). depending on which antigen is investigated, from 3 to ...	1997	9314081
acquired immunity to an intracellular pathogen: immunologic recognition of l. monocytogenes-infected cells.	listeria monocytogenes (l. monocytogenes) is a pathogenic bacterium, and subclinical infection in mice is utilized as a prototypic model to investigate the development and expression of acquired resistance to facultative intracellular organisms. a key virulence factor of l. monocytogenes is the hemolysin listeriolysin o (llo), and balb/c mice immunized with hemolysin-secreting strains of l. monocytogenes develop specific acquired resistance, while mice immunized with hemolysin-negative strains o ...	1997	9314082
recombinant listeria monocytogenes as a live vaccine vehicle and a probe for studying cell-mediated immunity.	the ability of listeria monocytogenes (l. monocytogenes) to enter the cytosol of host cells allows secreted proteins to efficiently enter the endogenous antigen-processing pathway leading to presentation by mhc class i molecules. l. monocytogenes has recently been exploited as a live vaccine vehicle for the induction of immunological memory against heterologous antigens. we have established a genetic system for site-specific integration of antigen expression cassettes into the listeria genome wh ...	1997	9314083
listeria monocytogenes: a potent vaccine vector for neoplastic and infectious disease.	listeria monocytogenes (l. monocytogenes) is a promising candidate vaccine vector that naturally infects antigen-presenting cells, and targets antigen delivery to both the class i mhc pathway of endogenous antigen presentation and the class ii pathway of exogenous antigen presentation. at the same time, l. monocytogenes stimulates the innate immune response to produce cytokines that enhance antigen-presenting function and induce a th1-type cytokine profile associated with cell-mediated immune re ...	1997	9314084
ph-dependent perforation of macrophage phagosomes by listeriolysin o from listeria monocytogenes.	the pore-forming toxin listeriolysin o (llo) is a major virulence factor implicated in escape of listeria monocytogenes from phagocytic vacuoles. here we describe the ph-dependence of vacuolar perforation by llo, using the membrane-impermeant fluorophore 8-hydroxypyrene-1,3,6-trisulfonic acid (hpts) to monitor the ph and integrity of vacuoles in mouse bone marrow-derived macrophages. perforation was observed when acidic vacuoles containing wild-type l. monocytogenes displayed sudden increases in ...	1997	9314564
the mechanism of cell death in listeria monocytogenes-infected murine macrophages is distinct from apoptosis.	various pathogenic bacteria with the capacity to live within eukaryotic cells activate an apoptotic program in infected host cells. induction of apoptosis by listeria monocytogenes in murine dendritic cells and hepatocytes has been described. here we address the questions of whether and how the pathogen kills macrophages, its most important habitat. employing several complementary techniques aimed at discriminating between apoptosis and necrosis, we show that murine bone marrow-derived macrophag ...	1997	9317010
in vivo and in vitro activation and expansion of gammadelta t cells during listeria monocytogenes infection in humans.	serial flow cytometry analyses of peripheral blood mononuclear cells obtained from 8 patients infected with listeria monocytogenes showed a higher percentage (p < 0.01) of gammadelta t cells (median, 11.7; range, 3.7 to 35.3) than did 16 age-matched uninfected controls (1.7, 0.4 to 13). most in vivo-expanded gammadelta t cells expressed the vgamma9 and vdelta2 gene products and displayed a memory phenotype (cd45ro[high]), and patients' gammadelta t cells expressed significantly more (p < 0.01) a ...	1997	9317036
phenotypic and functional characterization of mice that lack the type i receptor for il-1.	il-1 alpha and il-1 beta bind to receptors termed the type i and type ii il-1 receptors. the type i il-1 receptor is responsible for specific signaling, while the type ii il-1 receptor functions as a nonsignaling decoy receptor. to determine the effect of a defect in il-1-mediated signaling, mice have been produced with a genetically disrupted type i il-1 receptor gene. mice lacking type i il-1 receptors are of normal vigor and exhibit no overt phenotype. b cells from type i il-1r-/- mice activa ...	1997	9317135
listeriosis in p47(phox-/-) and trp55-/- mice: protection despite absence of roi and susceptibility despite presence of rni.	the significance of host defense mechanisms in primary listeriosis in vivo is incompletely understood. here, we show that tumor necrosis factor receptor p55-/- (trp55-/-) mice are susceptible to listeria monocytogenes infection in the presence of leukocyte recruitment, inflammatory cytokine production (including ifngamma), nitric oxide synthesis, and oxidative burst formation. mice deficient for oxidative burst (p47[phox-/-] mice) are relatively resistant to listeriosis. despite activation of th ...	1997	9324362
effects of fumonisin b1 on the immune system of sprague-dawley rats following a 14-day oral (gavage) exposure.	the effects of fumonisin b1 (fb1) on the immune system of sprague-dawley rats were investigated. groups of male and female rats (10 rats/group) were gavaged daily for 14 days with doses of 0, 5, 15, and 25 mg/kg body wt/day and the primary (igm) response to sheep red blood cells expressed as plaque-forming cell numbers/10(6) spleen mononuclear leukocytes (pfc/10(6) splenocytes) and pfc/spleen was determined. there was a significant dose-related linear trend toward decreased pfc/10(6) splenocytes ...	1997	9325027
critical role of anteiso-c15:0 fatty acid in the growth of listeria monocytogenes at low temperatures.	listeria monocytogenes is a food-borne pathogen capable of growth at refrigeration temperatures. membrane lipid fatty acids are major determinants of a sufficiently fluid membrane state to allow growth at low temperatures. l. monocytogenes was characterized by a fatty acid profile dominated to an unusual extent (> 95%) by branched-chain fatty acids, with the major fatty acids being anteiso-c15:0, anteiso-c17:0, and iso-c15:0 in cultures grown in complex or defined media at 37 degrees c. determin ...	1997	9327552
factors controlling acid tolerance of listeria monocytogenes: effects of nisin and other ionophores.	the acid tolerance of a listeria monocytogenes serotype 4b strain was studied by measuring its ability to survive at an acidic ph at 37 degrees c. the acid tolerance of l. monocytogenes was much lower than those of escherichia coli o157:h7 and shigella flexneri strains. this observation suggested a higher infective dose for l. monocytogenes than e. coli o157:h7 and shigella. the susceptibility of l. monocytogenes to acidic ph was dependent upon growth medium ph and growth phase of the culture. n ...	1997	9327581
evidence for intrathecal synthesis of alternative pathway complement activation proteins in experimental meningitis.	complement has been shown to contribute to intrathecal inflammation in bacterial meningitis. however, the cellular source of complement in the infected central nervous system has not been determined. in this study, we analyzed protein and mrna expression of two alternative pathway complement activation proteins, c3 and factor b, in the brains of mice with listeria monocytogenes meningitis. complement protein levels were found elevated in the cerebrospinal fluid of infected mice, compared with mo ...	1997	9327721
antagonistic effects of il-4 and interferon-gamma (ifn-gamma) on inducible nitric oxide synthase expression in bovine macrophages exposed to gram-positive bacteria.	cytokine-mediated modulation of nitric oxide (no) production by bacteria-stimulated bovine macrophages was studied. when salmonella dublin, as a prototypic gram-negative organism, was used, no generation was barely enhanced by recombinant bovine and ovine ifn-gamma, but was suppressed by il-4. salmonella dublin-induced no generation was not influenced by a panel of nine other cytokines. the panel included il-1, tumour necrosis factor (tnf) and ifn-alpha, which are active in a similar mouse macro ...	1997	9328118
issues in the management of bacterial meningitis.	acute bacterial meningitis is associated with significant morbidity and mortality despite the availability of effective antimicrobial therapy. the emergence of antibiotic-resistant bacterial strains in recent years has necessitated the development of new strategies for empiric antimicrobial therapy for bacterial meningitis. specifically, the emergence of strains of streptococcus pneumoniae that are resistant to penicillin and the cephalosporins have led to empiric therapy for patients with pneum ...	1997	9337758
listeria monocytogenes empyema in an hiv infected patient.	listeriosis in hiv infected patients is uncommon and usually presents as meningitis or bacteraemia. pleural fluid infections caused by this organism are extremely rare. a case is described of empyema caused by listeria monocytogenes in an hiv infected patient that was successfully treated with medical treatment only.	1997	9337838
genetic analysis of regions involved in replication and cadmium resistance of the plasmid pnd302 from lactococcus lactis.	the 8.8-kb lactococcus lactis plasmid pnd302 encodes resistance to cadmium (cdr). regions of pnd302 involved in replication and cdr were subcloned and sequenced. the replication region is localized on a 1.5-kb region and consists of an open reading frame (repb) preceded by a noncoding at-rich sequence (ori) which is highly homologous to lactococcal theta-type replicons. the cdr determinant is localized on a 2.9-kb region and encodes putative proteins similar to the cd(2+)-specific p-type efflux ...	1997	9339465
[the ribonuclease activity of bacteria as a factor in the persistence of the causative agents of sapronotic infections].		1997	9341006
the listeria monocytogenes iap gene as an indicator gene for the study of prfa-dependent regulation.	the iap gene of listeria monocytogenes encodes the extracellular protein p60, which possesses a murein hydrolase activity necessary for septum separation. we constructed l. monocytogenes egd strains harbouring plasmids that carry the iap gene under the control of the prfa-regulated promoters of the l. monocytogenes genes hly, mpl, and acta. after insertional inactivation of the chromosomal iap gene in l. monocytogenes egd, p60 synthesis was strictly dependent on prfa. elevated temperature (40 de ...	1997	9341679
recombinant listeria monocytogenes vaccination eliminates papillomavirus-induced tumors and prevents papilloma formation from viral dna.	listeria monocytogenes is a gram-positive, facultative intracellular bacterium that enters the cytoplasm of infected cells and spreads directly into neighboring cells without encountering the extracellular environment. cytoplasmic l. monocytogenes efficiently presents secreted proteins to the major histocompatibility complex class i pathway which can stimulate protective t-cell-mediated immune responses. we have used a cottontail rabbit papillomavirus (crpv) rabbit model to test the ability of r ...	1997	9343203
an outbreak of listeriosis suspected to have been caused by rainbow trout.	an outbreak of listeriosis in sweden, consisting of nine cases, was investigated by means of molecular typing of strains from patients and strains isolated from suspected foodstuffs, together with interviews of the patients. listeria monocytogenes was isolated from six of the patients, and all isolates were of the same clonal type. this clonal type was also isolated from a "gravad" rainbow trout, made by producer y, found in the refrigerator of one of the patients. unopened packages obtained fro ...	1997	9350756
bacterial flavohaemoglobins: a consensus sequence and identification of a discrete enterobacterial group and of further bacterial globins.	the amino acid sequences of haemoglobin-like proteins from the bacteria alcaligenes eutrophus, bacillus subtilis, erwinia chrysanthemi, escherichia coli, vibrio parahaemolyticus, vitreoscilla sp. and the yeast saccharomyces cerevisiae were studied. phylogenies based on distance and parsimony analysis showed that the eubacterial group can be easily distinguished from the other haemoglobin-like proteins. the construction of a consensus bacterial flavohaemoglobin based on the alignment of six bacte ...	1997	9351199
subtyping of listeria monocytogenes on the basis of plasmid profiles and arsenic and cadmium susceptibility.	the susceptibilities to arsenic and cadmium together with the detection of plasmid dna were evaluated for use as epidemiological markers for the subtyping of listeria monocytogenes. plasmid dna was detected in 34% of 322 apparently unrelated isolates of l. monocytogenes. the resistance to cadmium and arsenic differentiated 565 apparently unrelated cultures into four groups, the smallest being 5% of cultures resistant to both agents, and the largest (53%) being sensitive to cadmium and resistant ...	1997	9351219
combined effect of bacteriocin-producing lactic acid bacteria and lactoperoxidase system activation on listeria monocytogenes in refrigerated raw milk.	the bactericidal activity of three bacteriocin-producing lactic acid bacteria alone and in combination with milk lactoperoxidase (lp) system activation against listeria monocytogenes in refrigerated raw milk was studied. after 4 d at 4 degrees c, the population of l. monocytogenes in milk inoculated with bacteriocin-producing lactococcus lactis subsp. lactis atcc 11454, l. lactis subsp. lactis esi 515 or enterococcus faecalis inia 4 was reduced by 0.21-0.24 log units. activation of the lp system ...	1997	9351220
isolation and characterization of nisin-producing lactococcus lactis subsp. lactis from bean-sprouts.	bacterial isolates from bean-sprouts were screened for anti-listeria monocytogenes bacteriocins using a well diffusion method. thirty-four of 72 isolates inhibited the growth of l. monocytogenes scott a. one, hpb 1688, which had the biggest inhibition zone against l. monocytogenes scott a, was selected for subsequent analysis. both ribotyping and dna sequencing of 16s ribosomal rna gene demonstrated that the isolate was lactococcus lactis subsp. lactis. polymerase chain reaction and nucleotide s ...	1997	9351230
significance of temperature and preincubation temperature on survival of listeria monocytogenes at ph 4.8.	listeria monocytogenes is a food-borne pathogenic bacterium that can be found in soft cheese. at the beginning of cheese ripening, the ph is about 4.85-4.90. the aim of this work was to study the influence of temperature, preincubation temperature (temperature at which the inoculum was cultivated) and initial bacterial concentration on the survival of l. monocytogenes (strain scott a) at ph 4.8. it was demonstrated in an earlier study that these factors did influence growth kinetics. survival st ...	1997	9351274
uptake of pathogenic intracellular bacteria into human and murine macrophages downregulates the eukaryotic 26s protease complex atpase gene.	a differential pcr technique detected the transcriptional downregulation of the mss1 (mammalian suppressor of svg1) gene in murine j774a.1 macrophages following uptake of salmonella typhimurium. this downregulation was also noted after entry of virulent strains of listeria monocytogenes and shigella flexneri, two other facultative intracellular bacterial species. in contrast, uptake of nonpathogenic escherichia coli hb101, an aroa mutant of s. typhimurium, an invasion plasmid antigen b (ipab) mu ...	1997	9353061
immune cd8+ t lymphocytes lyse listeria monocytogenes-infected hepatocytes by a classical mhc class i-restricted mechanism.	hepatocytes constitute the principal site of listerial replication in the livers of mice infected i.v. cd8+ t lymphocytes play a predominant role in the host defenses to listeria monocytogenes. in vitro experiments by others undertaken to delineate the functions of cd8+ t lymphocytes have focused primarily on their interaction with listeria-infected macrophages. such experiments do not address directly the role of cd8+ t lymphocytes in eliminating the bulk of listeria replicating within the live ...	1997	8977201
il-6 produced by macrophages infected with mycobacterium species suppresses t cell responses.	the ability of mycobacterium bovis calmette-guérin bacillus-infected bone marrow-derived macrophages to process and present exogenously added ags to t cells and stimulate their growth and production of il-2 was examined. the infected macrophages were inhibited in their ability to activate t cells, and this inhibition could be transferred to uninfected macrophages with filtered supernatants from mycobacteria-infected macrophages. the inhibition was not due to decreases in macrophage viability, ag ...	1997	8977207
antigen-driven but not lipopolysaccharide-driven il-12 production in macrophages requires triggering of cd40.	we demonstrated that two distinct pathways exist for the induction of il-12 in apc. the first pathway for il-12 production occurred during responses to t cell-dependent ags such as ova and required triggering of cd40 molecules on the apc. il-12 production in this t cell-dependent system increased in direct proportion to ag concentration and required tcr ligation but not cd28 costimulation. the second pathway occurred when bacterial products such as lps or heat-killed listeria monocytogenes were ...	1997	8977211
a nucleic acid sequence-based amplification system for detection of listeria monocytogenes hlya sequences.	a nucleic acid sequence-based amplification system primarily targeting mrna from the listeria monocytogenes hlya gene was developed. this system enabled the detection of low numbers (< 10 cfu/g) of l. monocytogenes cells inoculated into a variety of dairy and egg products after 48 h of enrichment in modified listeria enrichment broth.	1997	8979357
an outbreak of gastroenteritis and fever due to listeria monocytogenes in milk.	after an outbreak of gastroenteritis and fever among persons who attended a picnic in illinois, chocolate milk served at the picnic was found to be contaminated with listeria monocytogenes.	1997	8988887
listeria gastroenteritis--old syndrome, new pathogen.		1997	8988894
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 ...	1997	9036973
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 ...	1997	9037109
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 ...	1997	9037762
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 ...	1997	9038298
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 ...	1997	9038306
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 ...	1997	9038307
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.	1997	9038321
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 ...	1997	9038598
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 ...	1997	9039562
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 ...	1997	9039563
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 ...	1997	9039566
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 ...	1997	9039568
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 ...	1997	9039576
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.	1997	9039774
grand entry for listeria.		1997	9041273
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 ...	1997	9042389
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 ...	1997	9043941
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 ...	1997	9043952
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 ...	1997	9044049
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 ...	1997	9045810
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.	1997	9046894
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 ...	1997	9049996
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 ...	1997	9049997
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.	1997	9050001
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 ...	1997	9055423
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 ...	1997	9055431
infections in solid-organ transplant recipients.	solid-organ transplantation is a therapeutic option for many human diseases. infections are a major complication of solid-organ transplantation. all candidates should undergo a thorough infectious-disease screening prior to transplantation. there are three time frames, influenced by surgical factors, the level of immunosuppression, and environmental exposures, during which infections of specific types most frequently occur posttransplantation. most infections during the first month are related t ...	1997	8993860
listeriosis.		1997	8994747
actin polymerization is induced by arp2/3 protein complex at the surface of listeria monocytogenes.	the pathogenic bacterium listeria monocytogenes is capable of directed movement within the cytoplasm of infected host cells. propulsion is thought to be driven by actin polymerization at the bacterial cell surface, and moving bacteria leave in their wake a tail of actin filaments. determining the mechanism by which l. monocytogenes polymerizes actin may aid the understanding of how actin polymerization is controlled in the cell. actin assembly by l. monocytogenes requires the bacterial surface p ...	1997	9000076
clavanins, alpha-helical antimicrobial peptides from tunicate hemocytes.	hemocytes from the invertebrate styela clava, a solitary tunicate, contained a family of four alpha-helical antimicrobial peptides that were purified, sequenced and named clavanins a, b, c and d. each clavanin contained 23 amino acid residues and was c-terminally amidated. the tunicate peptides resembled magainins in size, primary sequence and antibacterial activity. synthetic clavanin a was prepared and displayed comparable antimicrobial activity to magainins and cecropins. the presence of alph ...	1997	9001389
critical roles of neutrophils in host defense against experimental systemic infections of mice by listeria monocytogenes, salmonella typhimurium, and yersinia enterocolitica.	this study shows that neutrophils are critical for combating experimental systemic infections of mice by the bacterial pathogens listeria monocytogenes, salmonella typhimurium, and yersinia enterocolitica. it shows that mice rendered neutropenic by treatment with the granulocyte-depleting monoclonal antibody rb6-8c5 are far more susceptible than immunocompetent mice to infection with each of these three pathogens. compared to immunocompetent mice, neutropenic mice exhibit several defects in thei ...	1997	9009323
complementation of listeria seeligeri with the plca-prfa genes from l. monocytogenes activates transcription of seeligerolysin and leads to bacterial escape from the phagosome of infected mammalian cells.	infection experiments have shown that the avirulent species listeria seeligeri invaded the enterocyte-like cell line caco-2 with low efficiency but was unable to escape from the phagosome. introduction of the listeriolysin gene (hly) from l. monocytogenes into l. seeligeri via a recombinant plasmid did not change these characteristics. no measurable transcription of this gene or of the structurally intact chromosomal seeligerolysin gene (lso) was detected. transformation with a plasmid carrying ...	1997	9011051
actin dynamics in vivo.	actin dynamics in lamellipodia are driven by continuous cycles of actin polymerization, retrograde flow, and depolymerization. in the past year, advances have been made in identifying signaling pathways that regulate actin-filament uncapping and polymerization, in determining the role of myosin motor proteins in retrograde flow, and in evaluating the role of severing proteins in actin depolymerization. both listeria monocytogenes and saccharomyces cerevisiae have emerged as powerful model organi ...	1997	9013669
actin and cell pathogenesis.	the bacterial pathogens listeria monocytogenes and shigella flexneri recruit host factors that enable them to use actin polymerization as the driving force to facilitate their spread into neighbouring cells. it is now becoming clear that other pathogens, including viruses, have developed a number of different strategies to use the actin cytoskeleton of the host to their advantage during the infection process.	1997	9013675
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 ...	1997	9023932
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 ...	1997	9023935