Publications

typing of listeria monocytogenes strains by repetitive element sequence-based pcr.	listeria monocytogenes strains possess short repetitive extragenic palindromic (rep) elements and enterobacterial repetitive intergenic consensus (eric) sequences. we used repetitive element sequence-based pcr (rep-pcr) to evaluate the potential of rep and eric elements for typing l. monocytogenes strains isolated from humans, animals, and foods. on the basis of rep-pcr fingerprints, l. monocytogenes strains were divided into four major clusters matching origin of isolation. rep-pcr fingerprints ...	1999	9854072
cell wall teichoic acid glycosylation in listeria monocytogenes serotype 4b requires gtca, a novel, serogroup-specific gene.	we have identified a novel gene, gtca, involved in the decoration of cell wall teichoic acid of listeria monocytogenes serotype 4b with galactose and glucose. insertional inactivation of gtca brought about loss of reactivity with the serotype 4b-specific monoclonal antibody c74.22 and was accompanied by a complete lack of galactose and a marked reduction in the amounts of glucose on teichoic acid. interestingly, the composition of membrane-associated lipoteichoic acid was not affected. complemen ...	1999	9882654
induction of protective t cells against listeria monocytogenes in mice by immunization with a listeriolysin o-negative avirulent strain of bacteria and liposome-encapsulated listeriolysin o.	only listeriolysin o (llo)-producing strains of listeria monocytogenes generate protective immunity in mice. based on the findings that endogenous gamma interferon (ifn-gamma) production was induced only by such strains and that purified llo could induce ifn-gamma from nk cells, we have postulated that llo may play a pivotal role in the induction of th1-type protective t cells, which are highly dependent on ifn-gamma. in this study, mice were immunized with l. monocytogenes atcc 15313, an llo-no ...	1999	9916060
update: multistate outbreak of listeriosis--united states, 1998-1999.	from early august 1998 through january 6, 1999, at least 50 illnesses caused by a rare strain of the bacterium listeria monocytogenes, serotype 4b, have been reported to cdc by 11 states. six adults have died and two pregnant women have had spontaneous abortions. reported illness onset dates were during august 2-december 13, 1998. cdc and state and local health departments have identified the vehicle for transmission as hot dogs and possibly deli meats produced under many brand names by one manu ...	1999	9921730
quantitative pcr for listeria monocytogenes with colorimetric detection.	an enzyme-linked immunosorbent assay (elisa)-mediated polymerase chain reaction (pcr) technique was developed to detect and quantify listeria monocytogenes in food products. the bacterial dna was extracted from artificially contaminated food and co-amplified with a synthetic internal standard (is) using primers specific for the target gene coding for the invasive-associated protein (i.a.p.), a virulence factor of l. monocytogenes (i.a.p.) or is in the presence of fluorescein-dutp pcr products we ...	1999	9921826
high-pressure destruction kinetics of listeria monocytogenes on pork.	packaged fresh pork chops (30-g samples) containing an indigenous bacterial population of approximately 10(7) cfu/g were inoculated with 10(7) cfu of listeria monocytogenes scott a per g, heat sealed, and subjected to high-pressure processing at 200 to 400 mpa for up to 90 min. total counts and the number of surviving l. monocytogenes cells were determined by a spread plate technique on tryptic soy agar and modified oxford medium, respectively. the pressure destruction was characterized by a dua ...	1999	9921827
combined effect of nisin and moderate heat on destruction of listeria monocytogenes in cold-pack lobster meat.	the combined effect of nisin and moderate heat to increase the killing of listeria monocytogenes in cans of "cold-pack" lobster was investigated. adding nisin at a level of 25 mg/kg of can contents to the brine surrounding the lobster, in combination with a heat process giving internal can temperatures of 60 degrees c for 5 min and 65 degrees c for 2 min, resulted in decimal reductions of inoculated l. monocytogenes of 3 to 5 logs, whereas heat or nisin alone resulted in decimal reductions of 1 ...	1999	9921828
il-12 is not required for induction of type 1 cytokine responses in viral infections.	to investigate the physiological role of il-12 in viral infections in terms of t cell cytokine responses involved in virus-specific ig isotype induction and in antiviral protection, immune responses elicited upon infection of il-12-deficient mice with lymphocytic choriomeningitis virus (lcmv) or vesicular stomatitis virus (vsv) were studied. infection of il-12-deficient mice with lcmv induced a virus-specific type 1 cytokine response as determined by in vitro cytokine secretion patterns as well ...	1999	9916721
perforin-deficient cd8+ t cells: in vivo priming and antigen-specific immunity against listeria monocytogenes.	cd8+ t cells require perforin to mediate immunity against some, but not all, intracellular pathogens. previous studies with h-2b mhc perforin gene knockout (po) mice revealed both perforin-dependent and perforin-independent pathways of cd8+ t cell-mediated immunity to listeria monocytogenes (lm). in this study, we address two previously unresolved issues regarding the requirement for perforin in antilisterial immunity: 1) is cd8+ t cell-mediated, perforin-independent immunity specific for a sing ...	1999	9916723
antilisterial activity of peptide as-48 and study of changes induced in the cell envelope properties of an as-48-adapted strain of listeria monocytogenes.	the peptide as-48 is highly active on all listeria species. it has a bactericidal and bacteriolytic mode of action on listeria monocytogenes cect 4032, causing depletion of the membrane electrical potential and ph gradient. the producer strain enterococcus faecalis a-48-32, releases sufficient amounts of as-48 into the growth medium to suppress l. monocytogenes in cocultures at enterococcus-to-listeria ratios above 1 at 37 degreesc or above 10 at 15 degreesc. as the temperature decreases, the ba ...	1999	9925591
characterisation of listeria ivanovii isolates from the uk using pulsed-field gel electrophoresis.	forty-three listeria ivanovii isolates were collected in the uk between 1991 and 1997 from: 35 animal infections; two human infections; five foods; and one environmental source. a further two type strains of l. ivanovii (subsp. ivanovii and subsp. londoniensis) were obtained from a culture collection. these bacteria were characterised by conventional phenotypic methods and by pulsed-field gel electrophoresis (pfge) using apai and smai. forty-two of the isolates from the uk were identified as l. ...	1999	9933929
xenobiotic-metabolizing enzymes in carp (cyprinus carpio) liver, spleen, and head kidney following experimental listeria monocytogenes infection.	infection of carp with listeria monocytogenes 4b resulted in decreased liver, spleen, and head kidney enzyme activities, involved in the metabolism of xenobiotics. after infection, cytochrome p-450 levels and ethoxyresorufin o-deethylase (erod) activity were decreased while conjugation enzymes remained unaffected. the maximum decrease for phase i enzymes occurred on d 3. this loss of monooxygenase levels and activity could not be directly correlated with an increase in the number of organisms, a ...	1999	9973004
a transgenic model to analyze the immunoregulatory role of il-10 secreted by antigen-presenting cells.	il-10 is a cytokine secreted by a wide variety of cells type that has pleiotropic stimulatory and suppressive activities on both lymphoid and myeloid cells in vitro. to analyze the consequences of high il-10 secretion by apcs in immune responses, we produced transgenic mice expressing human il-10 directed by the mhc class ii ea promoter. despite alterations in the development of t and b cells, no gross abnormalities were detected in peripheral lymphocyte populations or serum ig levels. however, ...	1999	9973435
bacterial dna containing cpg motifs stimulates lymphocyte-dependent protection of mice against lethal infection with intracellular bacteria.	bacterial dna containing unmethylated cpg motifs activates mammalian lymphocytes and macrophages to produce cytokines and polyclonal ig. these include ifn-gamma, il-12, tnf-alpha, and il-6, which are important in the control of intracellular bacterial infection. here, we show that bacterial dna, as well as synthetic oligonucleotides containing cpg motifs, induce protection against large lethal doses of francisella tularensis live vaccine strain (lvs) and listeria monocytogenes. methylation of dn ...	1999	9973506
ctsr, a novel regulator of stress and heat shock response, controls clp and molecular chaperone gene expression in gram-positive bacteria.	clpp and clpc of bacillus subtillis encode subunits of the clp atp-dependent protease and are required for stress survival, including growth at high temperature. they play essential roles in stationary phase adaptive responses such as the competence and sporulation developmental pathways, and belong to the so-called class iii group of heat shock genes, whose mode of regulation is unknown and whose expression is induced by heat shock or general stress conditions. the product of ctsr, the first ge ...	1999	9987115
clpe, a novel member of the hsp100 family, is involved in cell division and virulence of listeria monocytogenes.	we identified, in the facultative intracellular pathogen listeria monocytogenes, a previously unknown clp atpase, unique among the hsp100 proteins because of the presence of a short n-terminal region with a potential zinc finger motif. this protein of 726 amino acids is highly homologous to clpe of bacillus subtilis, and is a member of a new subfamily of hsp100/clp atpases. the clpe gene is transcribed as a monocistronic mrna from a typical consensus sigma a promoter. clpe is not stimulated by v ...	1999	9987121
surface protein p104 is involved in adhesion of listeria monocytogenes to human intestinal cell line, caco-2.	adhesion of listeria monocytogenes to intestinal endothelial cells is an important initial event in the pathogenesis of infection which is not well understood. the suggestion has been made that some proteins, including internalin and actin polymerisation protein (acta), and carbohydrate molecules mediate, at least in part, the adhesion of listeria to certain cultured mammalian cells. this study investigated the role of a l. monocytogenes cell-surface protein of 104 kda (p104) in adhesion to huma ...	1999	9989638
impaired antibacterial host defense in mice lacking the n-formylpeptide receptor.	n-formylpeptides derive from bacterial and mitochondrial proteins, and bind to specific receptors on mammalian phagocytes. since binding induces chemotaxis and activation of phagocytes in vitro, it has been postulated that n-formylpeptide receptor signaling in vivo may be important in antimicrobial host defense, although direct proof has been lacking. here we test this hypothesis in mice lacking the high affinity n-formylpeptide receptor (fpr), created by targeted gene disruption. fpr-/- mice de ...	1999	9989980
t cell affinity maturation by selective expansion during infection.	t lymphocyte recognition of infected cells is mediated by t cell receptors (tcrs) interacting with their ligands, self-major histocompatibility complex (mhc) molecules complexed with pathogen-derived peptides. serial tcr interactions with potentially small numbers of mhc/ peptide complexes on infected cells transmit signals that result in t lymphocyte expansion and activation of effector functions. the impact of tcr affinity for mhc/peptide complexes on the rate or extent of in vivo t cell expan ...	1999	9989985
phenotype of mice and macrophages deficient in both phagocyte oxidase and inducible nitric oxide synthase.	the two genetically established antimicrobial mechanisms of macrophages are production of reactive oxygen intermediates by phagocyte oxidase (phox) and reactive nitrogen intermediates by inducible nitric oxide synthase (nos2). mice doubly deficient in both enzymes (gp91(phox-/-)/nos2(-/-)) formed massive abscesses containing commensal organisms, mostly enteric bacteria, even when reared under specific pathogen-free conditions with antibiotics. neither parental strain showed such infections. thus ...	1999	10023768
evaluation of an extended diagnostic pcr assay for detection and verification of the common causes of bacterial meningitis in csf and other biological samples.	a seminested polymerase chain reaction (pcr)-based diagnostic assay was evaluated for detection and verification of neisseria meningitidis, haemophilus influenzae, streptococcus pneumoniae, steptococcus agalactiae and listeria monocytogenes in cerebrospinal fluid (csf) and other biological samples. a general bacterial amplicon from the 16s rrna gene was amplified in a first step, and species-specific regions in a second. the detection level was 4 fg dna/reaction, corresponding to about one bacte ...	1999	10024433
role of listeria monocytogenes exotoxins listeriolysin and phosphatidylinositol-specific phospholipase c in activation of human neutrophils.	polymorphonuclear leukocytes (pmn) are essential for resolution of infections with listeria monocytogenes. the present study investigated the role of the listerial exotoxins listeriolysin (llo) and phosphatidylinositol-specific phospholipase c (plca) in human neutrophil activation. different listeria strains, mutated in individual virulence genes, as well as purified llo were used. coincubation of human neutrophils with wild-type l. monocytogenes provoked pmn activation, occurring independently ...	1999	10024552
noncompetitive expansion of cytotoxic t lymphocytes specific for different antigens during bacterial infection.	listeria monocytogenes is an intracellular bacterium that elicits complex cytotoxic t-lymphocyte (ctl) responses in infected mice. the responses of ctl populations that differ in antigen specificity range in magnitude from large, dominant responses to small, subdominant responses. to test the hypothesis that dominant t-cell responses inhibit subdominant responses, we eliminated the two dominant epitopes of l. monocytogenes by anchor residue mutagenesis and measured the t-cell responses to the re ...	1999	10024575
polyradiculitis, perimyocarditis, and nephrotic syndrome: unusual manifestations of infection due to listeria monocytogenes.		1999	10028095
purification, amino acid sequence and mode of action of bifidocin b produced by bifidobacterium bifidum ncfb 1454.	bifidocin b produced by bifidobacterium bifidum ncfb 1454 was purified to homogeneity by a rapid and simple three step purification procedure which included freeze drying, micro-cel adsorption/desorption and cation exchange chromatography. the purification resulted in 18% recovery and an approximately 1900-fold increase in the specific activity and purity of bifidocin b. treatment with bifidocin b caused sensitive cells to lose high amounts of intracellular k+ ions and u.v.-absorbing materials, ...	1999	10030011
sub-lethal damage of listeria monocytogenes after long-term chilled storage at 4 degrees c.	the possibility that long term in vitro chilled storage may result in sub-lethal damage to listeria monocytogenes cells was investigated by comparing growth of chill-stored (starvation at 4 degrees c) and fresh cultures on selective and non-selective media. growth of freshly grown cells was minimally (3-8%) affected by selective lsamm agar compared with non-selective brain heart infusion agar. in contrast, numbers of chill-stored strains were reduced by greater than 99% after direct plating on t ...	1999	10030031
resistance of heat-shocked cells of listeria monocytogenes to mano-sonication and mano-thermo-sonication.	heat shocks did not increase the resistance of listeria monocytogenes to an ultrasonication treatment under pressure (mano-sonication; ms). while heat-shocked cells (180 min, 45 degrees c) became sixfold more heat resistant than native cells (d62 = 1.8 min vs d62 = 0.24 min), the resistance of native and heat-shocked cells to ms (200 kpa, 117 microns) was the same (dms = 1.6 min). the inactivation rate of non-heat-shocked cells of l monocytogenes by a combined heat/ultrasonication treatment unde ...	1999	10030036
development and validation of a dynamic growth model for listeria monocytogenes in fluid whole milk.	listeria monocytogenes, a psychrotrophic microorganism, has been the cause of several food-borne illness outbreaks, including those traced back to pasteurized fluid milk and milk products. this microorganism is especially important because it can grow at storage temperatures recommended for milk (< or =7 degrees c). growth of l. monocytogenes in fluid milk depends to a large extent on the varying temperatures it is exposed to in the postpasteurization phase, i.e., during in-plant storage, transp ...	1999	10030637
fate of gram-positive bacteria in reconditioned, pork-processing plant water.	this study investigated the responses of enterococcus faecium (atcc 19433), staphylococcus aureus (196e), and listeria monocytogenes scott a in water from a local meat-processing plant. each bacterium was added to a starting count of 3 log10 cfu/ml and held from 5 to 28 degrees c. at intervals (0, 2, 7, 14, and 21 days), aliquots were plated on appropriate selective agars. in contrast to the gram-negative bacteria studied previously and which grew, the three gram-positive bacteria survived with ...	1999	10030641
the arp2/3 complex: a multifunctional actin organizer.	the actin-related proteins (arps) constitute a recently characterized family of proteins, many of which function as members of multiprotein complexes. the discovery that two family members, arp2 and arp3, act as multifunctional organizers of actin filaments in all eukaryotes has generated much excitement. over the past two years, newly discovered properties of the arp2/3 complex have suggested a central role in the control of actin polymerization. first, it promotes actin assembly on the surface ...	1999	10047519
a method for purification of listeriolysin o from a hypersecretor strain of listeria monocytogenes.	a simple and convenient method for the purification of the hemolytic toxin listeriolysin o (llo) from listeria monocytogenes is described. supernatants from bacteria cultures were purified by application to a ch2 spiral cartridge concentrator (amicon) and ion exchange chromatography. a critical step is removal of contaminating rna. the purified proteins had characteristics described for bacterial thiol-activated hemolysins: activation by a reducing agent (dtt) and inactivation by cholesterol. in ...	1999	10049682
pulsed-light inactivation of food-related microorganisms.	the effects of high-intensity pulsed-light emissions of high or low uv content on the survival of predetermined populations of listeria monocytogenes, escherichia coli, salmonella enteritidis, pseudomonas aeruginosa, bacillus cereus, and staphylococcus aureus were investigated. bacterial cultures were seeded separately on the surface of tryptone soya-yeast extract agar and were reduced by up to 2 or 6 log10 orders with 200 light pulses (pulse duration, approximately 100 ns) of low or high uv con ...	1999	10049899
dopamine beta-hydroxylase deficiency impairs cellular immunity.	norepinephrine, released from sympathetic neurons, and epinephrine, released from the adrenal medulla, participate in a number of physiological processes including those that facilitate adaptation to stressful conditions. the thymus, spleen, and lymph nodes are richly innervated by the sympathetic nervous system, and catecholamines are thought to modulate the immune response. however, the importance of this modulatory role in vivo remains uncertain. we addressed this question genetically by usin ...	1999	10051631
surface proteins of gram-positive bacteria and mechanisms of their targeting to the cell wall envelope.	the cell wall envelope of gram-positive bacteria is a macromolecular, exoskeletal organelle that is assembled and turned over at designated sites. the cell wall also functions as a surface organelle that allows gram-positive pathogens to interact with their environment, in particular the tissues of the infected host. all of these functions require that surface proteins and enzymes be properly targeted to the cell wall envelope. two basic mechanisms, cell wall sorting and targeting, have been ide ...	1999	10066836
infrarenal endoluminal bifurcated stent graft infected with listeria monocytogenes.	prosthetic graft infection as a result of listeria monocytogenes is an extremely rare event that recently occurred in a 77-year-old man who underwent endoluminal stent grafting for infrarenal abdominal aortic aneurysm. the infected aortic endoluminal prosthesis was removed by means of en bloc resection of the aneurysm and contained endograft with in situ aortoiliac reconstruction. at the 10-month follow-up examination, the patient was well and had no signs of infection.	1999	10069921
evaluation of accuracy and repeatability of identification of food-borne pathogens by automated bacterial identification systems.	the performances of five automated microbial identification systems, relative to that of a reference identification system, for their ability to accurately and repeatedly identify six common food-borne pathogens were assessed. the systems assessed were the microlog system (biolog inc., hayward, calif.), the microbial identification system (mis; midi inc., newark, del.), the vitek system (biomérieux vitek, hazelwood, mo.), the microscan walkaway 40 system (dade-microscan international, west sacra ...	1999	10074506
[listeria monocytogenes--an opportunist with serious intentions].		1999	10074828
[brain stem infection caused by listeria monocytogenes].	rhombencephalitis due to listeria monocytogenes is a serious form of brainstem inflammation. it is difficult to diagnose on the basis of clinical and laboratory findings alone. we describe a fatal case of listeria monocytogenes rhombencephalitis in a previously healthy female teenager. clinical and pathogenetic aspects of this condition are discussed.	1999	10074834
[listeria monocytogenes--the perfect parasite?].	the pathogen listeria monocytogenes has an extraordinary intracellular life cycle, based on adaption to and exploitation of normal cellular mechanisms. extracellular organisms induce their own phagocytosis, followed by destruction of the phagosomal membrane. cytoplasmatic bacteria organize the intracellular protein actin into "comet tails", and thus gain motility. in contact with the plasma membrane, motile bacteria induce a pseudopodium, corresponding to an invagination of the plasma membrane o ...	1999	10074835
live antigen carriers as tools for improved anti-tuberculosis vaccines.	recombinant (r) mycobacterium bovis bcg strains have been constructed which secrete biologically active listeriolysin (hly) fusion protein of listeria monocytogenes. in human and murine macrophage-like cell lines, intracellular persistence of these r-bcg strains was reduced as compared to the parental bcg strain. by immunogold labelling hly was detected in membrane structures and within the phagosomal space of macrophages. hly fusions consistently co-localized with a lysosome-associated membrane ...	1999	10076914
destruction of salmonella typhimurium, escherichia coli o157:h7 and listeria monocytogenes in chicken manure by drying and/or gassing with ammonia.	escherichia coli o157:h7 and listeria monocytogenes were able to grow for a period of 2 days in fresh chicken manure at 20 degrees c with a resulting 1-2 log units increase in cfu; salmonella typhimurium remained stable. prolongation of the storage time to 6 days resulted in a 1-2 log decreases of s. typhimurium compared to the initial count and a 3-4 log decrease of e. coli o157:h7; the number of l. monocytogenes did not decrease below the initial. these changes were accompanied by an increase ...	1999	10077842
evaluation of the api test, phosphatidylinositol-specific phospholipase c activity and pcr method in identification of listeria monocytogenes in meat foods.	the aim of this work was to compare the possibility of identifying listeria monocytogenes strains isolated from meat and sausage on the basis of the api-listeria test, production of phosphatidylinositol-specific phospholipase c (pi-plc) and polymerase chain reaction (pcr) for a dna fragment of the hlya gene encoding listeriolysin o. forty-six strains were isolated and examined. the lethality of some listeria isolates for balb/c mice was also determined. in this study, all isolates identified as ...	1999	10077846
the isoflavone genistein inhibits internalization of enteric bacteria by cultured caco-2 and ht-29 enterocytes.	the dietary isoflavone genistein is the focus of much research involving its role as a potential therapeutic agent in a variety of diseases, including cancer and heart disease. however, there is recent evidence that dietary genistein may also have an inhibitory effect on extraintestinal invasion of enteric bacteria. to study the effects of genistein on bacterial adherence and internalization by confluent enterocytes, caco-2 and ht-29 enterocytes (cultivated for 15-18 d and 21-24 d, respectively) ...	1999	10082767
petiveria alliacea l. extract protects mice against listeria monocytogenes infection--effects on bone marrow progenitor cells.	in this study we have investigated the effects of petiveria alliacea on the hematopoietic response of mice infected with listeria monocytogenes. our results demonstrate a protective effect of the crude extract of p. alliacea since the survival of the treated/infected was higher than that in the infected group. moreover, the number of granulocyte/macrophage colonies (cfu-gm) and the serum colony stimulating activity levels were increased in the treated/infected mice in relation to the infected gr ...	1999	10084333
effect of fetal calf serum on cytokine release by bone marrow-derived macrophages during infection with intracellular bacteria.	bone marrow-derived macrophages (bmm) comprise a population of quiescent cells which can be activated by defined signals. here, we directly compare the release of chemokines and monokines by bmm raised either in serum-supplemented or in serum-free medium in response to listeria monocytogenes egd or mycobacterium bovis bcg infection. we focused on this issue because there have been several controversial reports on the production of cytokines by bmm due to different in vitro culture conditions. cu ...	1999	10084700
critical observations on computerized analysis of banding patterns with commercial software packages.		1999	10084889
listeria monocytogenes phospholipase c-dependent calcium signaling modulates bacterial entry into j774 macrophage-like cells.	listeria monocytogenes secretes several proteins that have been shown to contribute to virulence. among these is listeriolysin o (llo), a pore-forming hemolysin that is absolutely required for virulence. two other virulence factors are phospholipases: a phosphatidylinositol-specific phospholipase c (pi-plc [plca]) and a broad-range plc (plcb). although mutations in plca or plcb resulted in small increases in mouse 50% lethal dose (ld50), deletions in both genes resulted in a 500-fold increase in ...	1999	10085017
examination of listeria monocytogenes intracellular gene expression by using the green fluorescent protein of aequorea victoria.	the acta protein of listeria monocytogenes is an essential virulence factor and is required for intracellular bacterial motility and cell-to-cell spread. plcb, cotranscribed with acta, encodes a broad-specificity phospholipase c that contributes to lysis of host cell vacuoles and cell-to-cell spread. construction of a transcriptional fusion between acta-plcb and the green fluorescent protein gene of aequorea victoria has facilitated the detailed examination of patterns of acta/plcb expression wi ...	1999	10085026
effects of interleukin-1 receptor antagonist overexpression on infection by listeria monocytogenes.	interleukin-1 receptor antagonist (il-1ra) is a naturally occurring cytokine whose only known function is the inhibition of interleukin-1 (il-1). using a reverse genetic approach in mice, we previously showed that increasing il-1ra gene dosage leads to reduced survival of a primary listerial infection. in this study, we characterize further the role of endogenously produced il-1ra and, by inference, il-1 in murine listeriosis. il-1ra overexpression inhibits, but does not eliminate, primary immun ...	1999	10085034
role of proteins of the ena/vasp family in actin-based motility of listeria monocytogenes.	intracellular propulsion of listeria monocytogenes is the best understood form of motility dependent on actin polymerization. we have used in vitro motility assays of listeria in platelet and brain extracts to elucidate the function of the focal adhesion proteins of the ena (drosophila enabled)/vasp (vasodilator-stimulated phosphoprotein) family in actin-based motility. immunodepletion of vasp from platelet extracts and of evl (ena/vasp-like protein) from brain extracts of mena knockout (-/-) mi ...	1999	10087267
[listeria meningitis].		1999	10088398
[listeriosis].		1999	10088413
functional deficiencies of peritoneal cells from gene-targeted mice lacking g-csf or gm-csf.	gene-targeted mice lacking the hemopoietic growth factors, granulocyte colony-stimulating factor (g-csf) or granulocyte-macrophage (gm)-csf, show increased susceptibility to infection with the facultative intracellular bacterium, listeria monocytogenes. the resident peritoneal cell populations from g-csf(-/-) and gm-csf(-/-) mice showed reduced production of the bactericidal molecule nitric oxide. macrophage-mediated tumoricidal activity and phagocytosis of listeria were reduced in g-csf(-/-), b ...	1999	10088609
lps down-regulates the expression of chemokine receptor ccr2 in mice and abolishes macrophage infiltration in acute inflammation.	interactions between chemokines and their specific receptors are important for leukocyte trafficking. the cc-chemokine monocyte chemoattractant protein-1 (mcp-1) and its specific receptor ccr2 are essential in monocytic infiltration and have been associated with several inflammatory diseases. it has been reported that several endotoxin and proinflammatory cytokines inhibit ccr2 expression in vitro in human monocytes. we report here that lipopolysaccharides (lps) down-regulated ccr2 expression bo ...	1999	10088610
isolation and detection of listeria monocytogenes using fluorogenic and chromogenic substrates for phosphatidylinositol-specific phospholipase c.	the bcm listeria monocytogenes detection system (lmds) consists of a selective preenrichment broth (lmpeb), selective enrichment broth (lmseb), selective/differential plating medium (lmpm), and identification on a confirmatory plating medium (lmcm). the efficacy of the bcm lmds was determined using pure cultures and naturally and artificially contaminated environmental sponges. the bcm lmpeb allowed the growth of listeria and resuscitation of heat-injured l. monocytogenes. the bcm lmseb, which c ...	1999	10090243
application of reuterin produced by lactobacillus reuteri 12002 for meat decontamination and preservation.	lactobacillus reuteri strain 12002 was used for reuterin production in the two-step fermentation process. a batch culture fermentation was used to produce a maximum biomass of l. reuteri. then cells were harvested, resuspended in a glycerol-water solution, and anaerobically incubated to produce reuterin. the lyophilized supernatants (approximately 4000 activity units (au) of reuterin per ml) were diluted in distilled water for decontamination and preservation trials. the mic values of reuterin f ...	1999	10090245
the mycobacterium tuberculosis reca intein can be used in an orftrap to select for open reading frames.	the dna repair protein reca of mycobacterium tuberculosis contains an intein, a self-splicing protein element. we have employed this mtu reca intein to create a selection system for successful intein splicing by inserting it into a kanamycin-resistance gene so that functional antibiotic resistance can only be restored upon protein splicing. we then proceeded to develop an orftrap, i.e., a selection system for the cloning of open reading frames (orfs). the orftrap exploits the self-splicing prope ...	1999	10091667
spectrum and antimicrobial activity of alexomycin (pnu-82, 127), a peptide compound projected for use in animal health.	alexomycin (pnu-82, 127) is a thiopeptide antimicrobial complex intended for veterinary practice that belongs to a series of cyclic peptides produced by streptomyces arginensis. mics against selected routine and fastidious clinical isolates of animal and human origin were determined by broth microdilution or agar dilution reference methods. alexomycin was active against gram-positive pathogens such as oxacillin-susceptible and -resistant staphylococcus aureus and coagulase-negative staphylococci ...	1999	10092967
detection of listeria monocytogenes in milk by the polymerase chain reaction.	a on the polymerase chain reaction (pcr) method based was developed for detection of listeria monocytogenes in milk samples after enrichment culture. it consists of culturing samples in listeria enrichment broth, followed by dna extraction and detection of the organism using pcr. dilutions of l. monocytogenes in milk were subjected to pcr amplification after enrichment culture. when determining the sensitivity of the method, it was found to be possible to detect 37 cfu (colony forming unit gl/ml ...	1999	10096164
characterization of listeria monocytogenes from an ice cream plant by serotyping and pulsed-field gel electrophoresis.	one dominating strain of serotype 1/2b was found when serotyping and pulsed-field gel electrophoresis (pfge) patterns were used for the characterization of 41 listeria monocytogenes isolates originating from an ice cream plant. samples were taken from the production environment, equipment and ice cream during the years 1990-1997. serotyping divided the isolates into two serovars, 1/2b and 4b. three rare-cutting enzymes (apai, asci and smai) were used in the creation of pfge patterns. asci result ...	1999	10100898
a model describing the relationship between regrowth lag time and mild temperature increase for listeria monocytogenes.	in order to comply with the consumer demand for ready-to-eat and look 'fresh' products, mild heat treatment will be used more and more in the agrofood industry. nonetheless there is no tool to define the most appropriate mild heat treatment. in order to build this tool, it is necessary to study and describe the response of a bacterial population to a mild increase in temperature, from the dynamic point of view. the response to a mild increase in temperature, defined by stress duration and temper ...	1999	10100905
comparative survival of salmonella typhimurium dt 104, listeria monocytogenes, and escherichia coli o157:h7 in preservative-free apple cider and simulated gastric fluid.	this study compared the survival of three-strain mixtures (ca. 10(7) cfu ml(-1) each) of salmonella typhimurium dt104, listeria monocytogenes, and escherichia coli o157:h7 in pasteurized and unpasteurized preservative-free apple cider (ph 3.3-3.5) during storage at 4 and 10 degrees c for up to 21 days. s. typhimurium dt104 populations decreased by <4.5 log10 cfu ml(-1) during 14 days storage at 4 and 10 degrees c in pasteurized cider, and by > or =5.5 log10 cfu ml(-1) during 14 days in unpasteur ...	1999	10100906
differential expression of listeria monocytogenes virulence genes in mammalian host cells.	we have used rt-pcr and gfp-mediated fluorescence to analyse the regulation of prfa-dependent virulence genes of listeria monocytogenes during proliferation in mammalian host cells. our data show that most of the prfa-regulated virulence genes are more efficiently expressed, as measured by transcript levels, when l. monocytogenes is grown in macrophages and macrophage-like cells rather than in epithelial cells, hepatocytes or endothelial cells. the promoters for hly and plca are predominantly ac ...	1999	10102368
use of automated ribotyping of austrian listeria monocytogenes isolates to support epidemiological typing.	we used automated ribotyping on the riboprinter microbial characterization system to study the epidemiology of listeriosis in western austria over the period 1988-1996. thirty-six isolates containing three serotypes were included in this collection. each of the 16 ribotype groupings (ribogroups) produced in this study contained a single serotype. isolates collected from within a single food factory environment all grouped into unique ribogroups. one factory contained isolates showing two unique ...	1999	10333075
presence of eubacteria in biopsies from crohn's disease inflammatory lesions as determined by 16s rrna gene-based pcr.	the aim of this study was to search for putative microbial agents in crohn's disease (cd) tissues by bacterial broad-range 16s rdna pcr combined with genus- and species-specific dna hybridisation analysis. biopsies taken both surgically and endoscopically from the terminal ileum of 11 cd patients and 11 control patients were investigated. significant amounts of eubacteria were demonstrated in biopsies taken endoscopically from both affected and unaffected individuals; the biopsies taken at surge ...	1999	10334593
porcine epithelial beta-defensin 1 is expressed in the dorsal tongue at antimicrobial concentrations.	epithelial cells and phagocytes contain antimicrobial polypeptides that participate in innate host defense. a recently cloned porcine beta-defensin, pbd-1, was detected by northern organ blots exclusively in the tongue epithelium. we generated recombinant pbd-1 peptide by using a baculovirus-insect cell expression system and obtained two forms (pbd-142 and pbd-138), which differed by n-terminal truncation. only pbd-142 was found in scrapings of the surface of the dorsal tongue or the buccal muco ...	1999	10338529
the wiskott-aldrich syndrome protein directs actin-based motility by stimulating actin nucleation with the arp2/3 complex.	actin polymerization at the cell cortex is thought to provide the driving force for aspects of cell-shape change and locomotion. to coordinate cellular movements, the initiation of actin polymerization is tightly regulated, both spatially and temporally. the wiskott-aldrich syndrome protein (wasp), encoded by the gene that is mutated in the immunodeficiency disorder wiskott-aldrich syndrome [1], has been implicated in the control of actin polymerization in cells [2] [3] [4] [5]. the arp2/3 compl ...	1999	10339430
identification of a new locus in listeria monocytogenes involved in cellobiose-dependent repression of hly expression.	expression of the prfa-controlled virulence gene hly (encoding the pore-forming cytolysin listeriolysin) is down-regulated by readily metabolized carbon sources in listeria monocytogenes. we isolated a tn917-insertional mutant of l. monocytogenes (strain lo28), which expressed a hemolytic phenotype in the presence of cellobiose. using hly fusions to luxaluxb genes, we show that hly expression was derepressed in the presence of cellobiose at the transcriptional level. surprisingly, hly expression ...	1999	10339818
application of high hydrostatic pressure to eliminate listeria monocytogenes from fresh pork sausage.	ground pork patties were inoculated separately with 10(9) cfu/g each of three strains of listeria monocytogenes obtained from the national animal disease center (nadc). inoculated patties were packaged under vacuum and treated at 414 megapascals (60,000 lb/in2) for up to 60 min by high hydrostatic pressure (hhp). survivors were determined by surface plating onto modified oxford agar and trypticase soy agar with yeast extract, as well as by the most probable number method using listeria enrichmen ...	1999	10340668
microbial, physical, and chemical quality of packaged ice in florida.	in a statewide survey, ice samples purchased at retail were evaluated for labeling information and microbiological, chemical, and physical quality. only 11% of bags from on-premises manual facilities, compared to 79% for off-premises mechanical facilities, had appropriate label information. one ice sample exceeded the state regulatory limit for aerobic plate count (apc) (<500 cfu/ml). yeasts and molds were detected in 12% of the samples. no listeria monocytogenes were found in any of the samples ...	1999	10340675
acid-adapted listeria monocytogenes displays enhanced tolerance against the lantibiotics nisin and lacticin 3147.	log-phase listeria monocytogenes cells become tolerant to a variety of environmental stresses following acid adaptation at ph 5.5. we demonstrated that adapted cells also exhibit increased tolerance to nisin and, to a lesser extent, lacticin 3147. at nisin concentrations of 100 and 200 iu/ml the survival of acid-adapted cells was approximately 10-fold greater than nonadapted cells. however, acid adaptation had only a moderate effect on the tolerance of l. monocytogenes to lacticin 3147, a phenom ...	1999	10340677
live virulent rhodococcus equi, rather than killed or avirulent, elicits protective immunity to r. equi infection in mice.	mice inoculated intravenously with a sublethal dose of live virulent rhodococcus equi atcc 33701 that contained an 85-kb virulence plasmid were immune to a lethal intravenous challenge of atcc 33701. this immunity depended upon the dose of immunization and developed rapidly: mice primed with 10(5) live atcc 33701 eliminated the challenged bacteria more rapidly than mice primed with doses ranging from 10(2) to 10(4) bacteria, and mice given 10(5) live atcc 33701 intravenously withstood the lethal ...	1999	10340706
influence of temperature and growth phase on expression of a 104-kilodalton listeria adhesion protein in listeria monocytogenes.	interaction of listeria monocytogenes with mammalian intestinal cells is believed to be an important first step in listeria pathogenesis. transposon (tn916) mutagenesis provided strong evidence that a 104-kda surface protein, designated the listeria adhesion protein (lap), was involved in adherence of l. monocytogenes to a human enterocyte-like caco-2 cell line (v. pandiripally, d. westbrook, g. sunki, and a. bhunia, j. med. microbiol. 48:117-124, 1999). in this study, expression of lap in l. mo ...	1999	10347076
synergistic effect of heat and sodium lactate on the thermal resistance of yersinia enterocolitica and listeria monocytogenes in minced beef.	the effect of sodium lactate (nal) (0, 2.4 or 4.8%), in heating and recovery media, on yersinia enterocolitica and listeria monocytogenes numbers recovered from minced beef heated at 55 degrees c, was examined. survivors were enumerated on selective media at ph 5.7/7.4 (y. enterocolitica) or ph 5.7/7.2 (l. monocytogenes). recovery of the organisms depended on the ph and nal levels in the recovery medium. the heat resistance of y. enterocolitica (p < 0.001) and l. monocytogenes (p < 0.01) decreas ...	1999	10347886
isolation, partial purification and characterization of a bacteriocin produced by a newly isolated bacillus subtilis strain.	a wild type micro-organism producing antibacterial substances has been isolated from a chinese fermented soybean seasoning and identified as bacillus subtilis. a crude antibacterial preparation (cabp) was obtained by ammonium sulphate precipitation. isoelectric focusing assay revealed at least four antimicrobial components in the cabp. however, in sds-page analysis, only one peptide band displayed antimicrobial activity against pathogenic bacillus cereus and listeria monocytogenes. this inhibito ...	1999	10347890
nisin and alta 2341 inhibit the growth of listeria monocytogenes on smoked salmon packaged under vacuum or 100% co2.	the effects of nisin and alta 2341 on the growth of listeria monocytogenes were assessed on smoked salmon packaged under vacuum or 100% co2. smoked salmon slices (ph 6.3) were inoculated with a cocktail of seven l. monocytogenes isolates at a level of approximately 2.5 log10 colony forming units (cfu) g-1. after inoculation, the surface of the smoked salmon slices was treated with either nisin (400 or 1250 iu g-1) or alta 2341 (0.1 or 1%). the smoked salmon was packaged and stored at 4 degrees c ...	1999	10347892
conjugative mobilization of the rolling-circle plasmid pip823 from listeria monocytogenes bm4293 among gram-positive and gram-negative bacteria.	we determined the sequence and genetic organization of plasmid pip823, which contains the dfrd gene; dfrd confers high-level trimethoprim resistance to listeria monocytogenes bm4293 by synthesis of dihydrofolate reductase type s2. pip823 possessed all the features of the pub110/pc194 plasmid family, whose members replicate by the rolling-circle mechanism. the rep gene encoded a protein identical to repu, the protein required for initiation of the replication of plasmids ptb913 from a thermophili ...	1999	10348847
antigen secreted from noncytosolic listeria monocytogenes is processed by the classical mhc class i processing pathway.	intracellular bacteria can reside in a vacuolar compartment, or they can escape the vacuole and become free living in the cytoplasm. the presentation of ag by class i mhc molecules has been defined primarily for ag present in the cytoplasm. it was therefore thought that ags from bacteria that remain in a vacuole would not be presented by mhc class i molecules. although some studies have provided data to support this idea, it is not necessarily true for all intracellular bacteria. for example, we ...	1999	10352246
inhibition of listeria monocytogenes by carnobacterium spp. strains in a simulated cold smoked fish system stored at 4 degrees c.	preservation of smoked salmon from bacterial spoilage, and especially from listeria monocytogenes by bacteriocin producers is a promising challenge. over a hundred lactic acid bacteria, isolated from commercial vacuum packaged cold smoked salmon, were screened for their antagonistic activity against l. innocua. twenty-two strains were able to produce bacteriocin-like proteinaceous substances. these strains were characterized physiologically and biochemically as carnobacterium strains. three diff ...	1999	10357271
analysis of the bacterial surface ripening flora of german and french smeared cheeses with respect to their anti-listerial potential.	the anti-listerial potential of 19 different french smeared cheese bacterial consortia was analyzed semi-quantitatively. comparison of the total viable cell count to the direct microscopic count yielded no indication that non-culturable bacteria contribute significantly to the undefined, complex ripening floras. from 2613 isolates, 48 showed clear inhibition of one or more listeria monocytogenes strains on solid medium, while only three isolates excreted an anti-listerial, soluble substance when ...	1999	10357277
a model based on absorbance data on the growth rate of listeria monocytogenes and including the effects of ph, nacl, na-lactate and na-acetate.	a mathematical model was developed for predicting the growth of l. monocytogenes at 9 degrees c in the presence of 70 ppm sodium nitrite, and at different levels of ph (5.5-6.5), sodium chloride (1.0-4.0%), sodium lactate (0-0.5%) and sodium acetate (0-0.6%). collection of the growth data was done using absorbance measurements in broth cultures and the absorbance measurement was evaluated. the model was compared to the food micromodel, and against the growth of l. monocytogenes in a vacuum-packe ...	1999	10357278
occurrence and typing of listeria monocytogenes strains in retail vacuum-packed fish products and in a production plant.	one hundred and ten samples of ready-to-eat, vacuum-packed, smoked and cold-salted fish products were collected from retail outlets in southern finland during 1996 for examination of the occurrence and level of listeria monocytogenes. the samples originated from 12 producers. positive samples with levels exceeding 100 cfu/g were encountered mainly in one of the producers (no. 8). therefore, 200 samples from the plant and the products of this producer were studied during august-september 1996 and ...	1999	10357279
bacterial infections in infants 60 days and younger: epidemiology, resistance, and implications for treatment.	to establish what might be more optimal initial antibiotic therapy for suspected invasive bacterial infections in infants 60 days or younger who are evaluated in the emergency department (ed).	1999	10357302
the listeria monocytogenes protein inlb is an agonist of mammalian phosphoinositide 3-kinase.	the gram-positive pathogen listeria monocytogenes induces its own internalization into some non-phagocytic mammalian cells by stimulating host tyrosine phosphorylation, phosphoinositide (pi) 3-kinase activity, and rearrangements in the actin cytoskeleton. entry into many cultured cell lines is mediated by the bacterial protein inlb. here we investigate the role of inlb in regulating mammalian signal transduction and cytoskeletal structure. treatment of vero cells with purified inlb caused rapid ...	1999	10358053
the ketolide antibiotic hmr 3647, a candidate substance for the treatment of systemic and intracerebral infections with listeria monocytogenes.	hmr 3647 is a novel macrolide derivative with a broad spectrum of activity against grampositive bacteria and some fastiduous gramnegative bacteria, anaerobes and toxoplasma gondii. in this work, its activity against the facultatively intracellular bacterium, listeria monocytogenes, was examined in vitro, in tissue culture and in animal models of systemic and intracerebral infection and compared with that of erythromycin. all strains of l. monocytogenes were susceptible to the substance, with min ...	1999	10360316
endogenous cytokines during a lethal 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 protective roles but that il-4 and il-10 play detrimental roles in nonlethal listeria monocytogenes infection in mice. in this paper, we studied the roles of endogenous cytokines in a lethal infection with l. monocytogenes in mice. tnf-alpha and il-6 titres in the bloodstreams, spleens and livers paralleled bacterial numbers in the org ...	1999	10361718
molecular epidemiology of an outbreak of febrile gastroenteritis caused by listeria monocytogenes in cold-smoked rainbow trout.	febrile gastroenteritis in five healthy persons was associated with the consumption of vacuum-packed cold-smoked rainbow trout containing listeria monocytogenes. l. monocytogenes isolates from the incriminated fish product lot and the stool samples were all of serotype 1/2a and were indistinguishable by pulsed-field gel electrophoresis employing asci and smai.	1999	10364616
pulsed high electric field causes 'all or nothing' membrane damage in listeria monocytogenes and salmonella typhimurium, but membrane h+-atpase is not a primary target.	salmonella typhimurium (cra 1005) was more sensitive than listeria monocytogenes (nctc 11994) to pulsed high electric field (phef) treatment in distilled water (10, 15 and 20 kv/cm), 10 mm tris-maleate buffer, ph 7.4 (15 kv/cm) and model beef broth (0.75%, w/v; 15 kv/cm). sublethal injury could not be detected using a selective medium plating technique, indicating that bacterial inactivation by phef may be an 'all or nothing' event. phef-induced membrane permeabilisation resulted in an increase ...	1999	10375130
listeriosis: recognizing it, treating it, preventing it.	listeria monocytogenes has become a major pathogen in foodborne illness. it most often affects patients who are pregnant, at the extremes of life, or immunocompromised in some way. a variety of clinical manifestations are possible, but bacteremia and meningitis are most common. this article reviews the epidemiology, microbiology, populations at risk, clinical manifestations, treatment, and prevention of listeriosis.	1999	10375847
dissemination of listeria monocytogenes by infected phagocytes.	in vitro data suggest that blood-borne listeria monocytogenes organisms enter the central nervous system (cns) by direct invasion of endothelial cells or by cell-to-cell spread from infected phagocytes to endothelial cells. however, a role for infected phagocytes in neuroinvasion and dissemination of l. monocytogenes in vivo has not been confirmed experimentally. experiments described here tested whether l. monocytogenes-infected peripheral blood leukocytes (pbl) circulated in bacteremic mice an ...	1999	10377133
interleukin 12-dependent interferon gamma production by cd8alpha+ lymphoid dendritic cells.	we investigated the role of antigen-presenting cells in early interferon (ifn)-gamma production in normal and recombinase activating gene 2-deficient (rag-2(-/-)) mice in response to listeria monocytogenes (lm) infection and interleukin (il)-12 administration. levels of serum ifn-gamma in rag-2(-/-) mice were comparable to those of normal mice upon either lm infection or il-12 injection. depletion of natural killer (nk) cells by administration of anti-asialogm1 antibodies had little effect on if ...	1999	10377194
differential immune responses in mice with left- and right-turning preference.	humoral and cell-mediated immune responses of inbred balb/c male mice were assayed for differential reactivities associated with behavioral sidedness, which was evaluated by spontaneous rotational behavior in a circular cage model system. mice with left-turning preference had lower in vivo primary igm and igg anti-keyhole limpet hemocyanin (klh) antibody responses, delayed-type hypersensitivity (dth) responses, and host-resistance against the intracellular bacteria, listeria monocytogenes, than ...	1999	10378880
defining the growth/no-growth interface for listeria monocytogenes in mexican-style cheese based on salt, ph, and moisture content.	the objective of this study was to define combinations of ph, salt, and moisture that produce growth, stasis, or inactivation of listeria monocytogenes in mexican-style cheese. a soft, directly acidified, rennet-coagulated, fresh cheese similar to mexican-style cheese was produced. the cheese was subsequently altered in composition as required by the experimental protocol. a factorial design with four moisture contents (42, 50, 55, and 60%), four salt concentrations (2.0, 4.0, 6.0, and 8.0% wt/w ...	1999	10382647
acid adaptation of listeria monocytogenes strains does not offer cross-protection against an activated lactoperoxidase system.	listeria monocytogenes has been implicated in foodborne illness outbreaks involving several types of cheeses made from acidified milk. acid shock response (asr) and acid tolerance response (atr) could be possible reasons for its survival. the asr and atr of three strains of l. monocytogenes (v7, v37, and ca) in skim milk acidified to ph 4.0 and 3.5 with lactic acid and held at 32 degrees c were studied. studies were also done to determine if acid adaptation of the organism enhanced survival in t ...	1999	10382659
the role of b cells in the establishment of t cell response in mice infected with an intracellular bacteria, listeria monocytogenes.	to clarify the role of b cells in the establishment of t cell response against intracellular bacteria, b-cell-deficient (mumt-/-) mice were infected with an intracellular bacteria, listeria monocytogenes, and t cell response against the bacteria was analyzed. on day 6 of primary listeria infection, spleen t cells of the mumt-/- mice showed significantly lower levels of proliferative response and ifn-gamma production than those of normal infected mice after in vitro stimulation with listerial ant ...	1999	10383820
genetic immunization of mice against listeria monocytogenes using plasmid dna encoding listeriolysin o.	the development of protective immunity against many intracellular bacterial pathogens commonly requires sublethal infection with viable forms of the bacteria. such infection results in the in vivo activation of specific cell-mediated immune responses, and both cd4+ and cd8+ t lymphocytes may function in the induction of this protective immunity. in rodent models of experimental infection with listeria monocytogenes, the expression of protective immunity can be mediated solely by the immune cd8+ ...	1999	10384131
physical and genetic map of the listeria monocytogenes egd serotype 1/2a chromosome.	listeria monocytogenes is a facultative intracellular pathogen responsible for both invasive and non-invasive food-borne illness in animals and humans. in this study, macrorestriction analysis following pulsed-field gel electrophoresis was used to show that listeria monocytogenes serovar 1/2a strain egd has a single chromosome containing eight noti fragments of 1100, 850, 365, 320, 275, 40, 30 and 20 kb in size and 11 asci fragments of 860, 470, 410, 360, 320, 250, 110, 80, 50, 30 and 20 kb. the ...	1999	10386380
characterization, production, and purification of leucocin h, a two-peptide bacteriocin from leuconostoc mf215b.	leuconostoc mf215b was found to produce a two-peptide bacteriocin referred to as leucocin h. the two peptides were termed leucocin halpha and leucocin hbeta. when acting together, they inhibit, among others, listeria monocytogenes, bacillus cereus, and clostridium perfringens. production of leucocin h in growth medium takes place at temperatures down to 6 degrees c and at ph below 7. the highest activity of leucocin h in growth medium was demonstrated in the late exponential growth phase. the ba ...	1999	10387116
apoptosis of caco-2 intestinal cells invaded by listeria monocytogenes: protective effect of lactoferrin.	the apoptosis of infected hepatocytes is a critical step in nonspecific defense against listeria monocytogenes infection. we have observed that infection by l. monocytogenes in enterocyte-like cells (caco-2) results in apoptosis. however, a large fraction of infected intestinal epithelial cells escape from cellular condensation and fragmentation, typical of programmed cell death, and become necrotic. the balance between apoptosis and necrosis seems to be influenced by the number of internalized ...	1999	10388533
production of monoclonal antibodies to listeria monocytogenes and their application to determine the virulence of isolates from channel catfish.	we produced monoclonal antibodies (mabs) to the extracellular proteins of listeria monocytogenes egd grown in chelex-treated improved minimal medium. ten of the positive hybridomas generated were chosen for further characterization. seven of the mabs reacted with a protein having a molecular mass of 60 kda. these mabs inhibited listeriolysin (llo)-mediated hemolysis, and two of them were specific for llo and none of the other thiol-activated toxins tested. in an enzyme-linked immunosorbent assay ...	1999	10388671