Publications

a cold-sensitive listeria monocytogenes mutant has a transposon insertion in a gene encoding a putative membrane protein and shows altered (p)ppgpp levels.	a cold-sensitive listeria monocytogenes mutant designated cld-14 was obtained by transposon tn917 mutagenesis. the gene interrupted by tn917 in cld-14 was the l. monocytogenes lmof2365_1485 homolog, which exhibits 45.7% homology to the bacillus subtilis yqff locus. lmof2365_1485, here designated pgph, encodes a putative integral membrane protein with a predicted molecular mass of 81 kda. pgph is predicted to contain a conserved n-terminal signal peptide sequence, seven transmembrane helices, and ...	2006	16751502
differential inla and inlb expression and interaction with human intestinal and liver cells by listeria monocytogenes strains of different origins.	in this study, a number of listeria monocytogenes strains of different origins were evaluated for in vitro invasion capacity for various human cell types (monocytic thp-1, enterocytic caco-2, and hepatocytic hepg2 cells) and for expression levels of specific virulence genes. for thp-1 cells, no differences between clinical and nonclinical l. monocytogenes strains in invasion capacity or in production of the proinflammatory cytokine interleukin-8 (il-8) were observed, whereas for the caco-2 and h ...	2006	16751490
a novel functional t cell hybridoma recognizes macrophage cell death induced by bacteria: a possible role for innate lymphocytes in bacterial infection.	we have established a novel tcralphabeta (tcrvbeta6)(+)cd4(-)cd8(-) t cell hybridoma designated b6ho3. when the b6ho3 cells were cocultured with bacterial-infected j774 macrophage-like cells, ifn-gamma production by b6ho3 cells was triggered through direct cell-cell contact with dying j774 cells infected with listeria monocytogenes (lm), shigella flexneri, or salmonella typhimurium that expressed the type iii secretion system, but not with intact j774 cells infected with heat-killed lm, nonhemol ...	2006	16751404
panr1, a dominant negative missense allele of the gene encoding tnf-alpha (tnf), does not impair lymphoid development.	a dominant hypomorphic allele of tnf, panr1, was identified in a population of g(1) mice born to n-ethyl-n-nitrosourea-mutagenized sires. macrophages from homozygotes produced no detectable tnf bioactivity, although normal quantities of immunoreactive tnf were secreted. the phenotype was confined to a critical region on mouse chromosome 17, and then ascribed to a c-->a transversion at position 3480 of the tnf gene, corresponding to the amino acid substitution p138t. as a result of subunit exchan ...	2006	16751399
contributions of listeria monocytogenes sigmab and prfa to expression of virulence and stress response genes during extra- and intracellular growth.	listeria monocytogenes sigmab and prfa are pleiotropic regulators of stress response and virulence gene expression. quantitative rt-pcr (qrt-pcr) was used to measure transcript levels of sigmab- and prfa-dependent genes in exponential-phase l. monocytogenes wild-type and deltasigb strains as well as in bacteria exposed to environmental stresses (0.3 m nacl or growth to stationary phase) or present in the vacuole or cytosol of human intestinal epithelial cells. stationary-phase or nacl-exposed l. ...	2006	16735745
listeriolysin o derived from listeria monocytogenes inhibits the effector phase of an experimental allergic rhinitis induced by ovalbumin in mice.	listeriolysin o (llo) derived from listeria monocytogenes is highly capable of inducing interleukin (il)-12, il-18 and interferon (ifn)-gamma, and facilitates the generation of th1 cells. we have recently shown that recombinant llo (rllo) inhibits generation of ovalbumin (ova)-specific th2 immune response by skewing maturation of antigen-specific t cells into th1 cells. in the present study, we investigated the effect of rllo on the effector phase of th2-dependent allergic rhinitis in balb/c mic ...	2006	16734617
listeria pleuritis 1 week after lung transplantation.	listeria monocytogenes is an important bacterial pathogen in immunocompromised patients, the elderly, pregnant women and transplant patients, but until now it has not been reported in lung transplants. we report the first case of listeriosis in a lung transplant recipient who presented with a pleural effusion 8 days after transplantation. after the introduction of a thorax drain and the administration of intravenous antibiotics during 3 weeks, the patient recovered completely. this case highligh ...	2006	16730581
control of listeria monocytogenes virulence by 5'-untranslated rna.	the gram-positive bacterium listeria monocytogenes uses a wide range of virulence factors for its pathogenesis. expression of five of these factors has previously been shown to be subjected to post-transcriptional regulation as a result of their long 5'-untranslated region (5'-utr). we have investigated the presence of 5'-utrs among the other known virulence genes and genes that encode putatively virulence-associated surface proteins. our results strongly suggest that l. monocytogenes controls m ...	2006	16730443
lactobacillus plantarum gene clusters encoding putative cell-surface protein complexes for carbohydrate utilization are conserved in specific gram-positive bacteria.	genomes of gram-positive bacteria encode many putative cell-surface proteins, of which the majority has no known function. from the rapidly increasing number of available genome sequences it has become apparent that many cell-surface proteins are conserved, and frequently encoded in gene clusters or operons, suggesting common functions, and interactions of multiple components.	2006	16723015
monitoring the microbial populations and temperatures of fresh broccoli from harvest to retail display.	microbial populations and the temperature of fresh broccoli were monitored at several steps of a supply chain by sampling 33 distinct lots of locally grown produce over two seasons during harvest, storage, wholesale handling, and retail display. imported broccoli was also sampled, but only at retail display. microbiological analyses were conducted on the florets of 201 local and 60 imported broccoli samples to determine populations of total aerobic bacteria (aerobic colony count), fecal coliform ...	2006	16715813
rabbit meat as a source of bacterial foodborne pathogens.	even though worldwide production of rabbit meat is >1,000,000 tons, little information is available for rabbit meat microbiology. this study provides data on the prevalence of salmonella, escherichia coli o157:h7, yersinia enterocolitica, listeria spp., motile aeromonas spp., and staphylococcus aureus on rabbit meat. a total of 24 rabbit carcasses from two abattoirs and 27 rabbit meat packages from supermarket displays were examined. in addition to culturing methods, associated virulence genes w ...	2006	16715811
pathogen survival in chorizos: ecological factors.	this study addressed health risks from ethnic sausages produced on a small scale, without inspection, in california and elsewhere. mexican-style chorizo, a raw pork sausage that is not cured, fermented, or smoked, was contaminated experimentally in the batter with escherichia coli o157:h7, listeria monocytogenes, or salmonella serotypes and stuffed into natural casings. formulations were based on a market survey in california. physical parameters that were controlled were ph, water activity (a(w ...	2006	16715809
thermal inactivation studies of escherichia coli o157:h7, salmonella, and listeria monocytogenes in ready-to-eat chicken-fried beef patties.	thermal inactivation studies were used to determine the d- and z-values of escherichia coli o157:h7, salmonella, and listeria monocytogenes in ready-to-eat chicken-fried beef patties. inoculated meat was packaged in sterile bags, which were immersed in a circulated water bath and held at 55, 57.5, 60, 62.5, 65, 67.5, and 70 degrees c for different lengths of time. d- and z-values were determined with a linear regression model. average d-values at temperatures 55 to 70 degrees c were 27.62 to 0.0 ...	2006	16715808
bacteriocin activity by lactobacillus curvatus cwbi-b28 to inactivate listeria monocytogenes in cold-smoked salmon during 4 degrees c storage.	the inhibition effectiveness of a bacteriocin produced by lactobacillus curvatus cwbi-b28 against listeria monocytogenes was investigated in cold-smoked salmon during storage at 4 degrees c. three bacteriocin-based strategies for the control of l. monocytogenes in foods (i.e., producing bacteriocin in situ, spraying with partially purified bacteriocin, and packaging in bacteriocin-coated plastic film), plus a newly developed method that uses cell-adsorbed bacteriocin (i.e., a suspension of produ ...	2006	16715806
inhibitory effect of select nitrocompounds on growth and survivability of listeria monocytogenes in vitro.	we report the effects of 2-nitro-1-propanol (2npoh), 2-nitroethanol (2neoh), and nitroethane (ne) on growth and survivability of listeria monocytogenes. in all cases, inhibition was greatest with 2npoh and least with ne. for example, specific growth rates of l. monocytogenes strain 18 declined (p < 0.05) 76, 60, and 29% from controls during aerobic culture at 37 degrees c in brain heart infusion broth containing 10 mm 2npoh, 2neoh, or ne, respectively. mean specific growth rate for the controls ...	2006	16715805
mechanism of action of spanish oregano, chinese cinnamon, and savory essential oils against cell membranes and walls of escherichia coli o157:h7 and listeria monocytogenes.	the mechanism of the antimicrobial action of spanish oregano (corydothymus capitatus), chinese cinnamon (cinnamomum cassia), and savory (satureja montana) essential oils against cell membranes and walls of bacteria was studied by the measurement of the intracellular ph and atp concentration, the release of cell constituents, and the electronic microscopy observations of the cells when these essential oils at their mics were in contact with escherichia coli o157:h7 and listeria monocytogenes. e. ...	2006	16715803
interleukin 15-dependent crosstalk between conventional and plasmacytoid dendritic cells is essential for cpg-induced immune activation.	the function of interleukin 15 (il-15) in unmethylated cpg oligodeoxynucleotide (cpg)-induced immune responses remains unknown. here, in response to cpg, both wild-type and natural killer cell-depleted mice produced il-12 and became resistant to a lethal dose of listeria monocytogenes. in contrast, cpg-treated il-15-deficient mice produced little il-12 and succumbed to l. monocytogenes. cpg-stimulated conventional dendritic cells (cdcs) were the main producers of both il-15 and il-12, but cdcs d ...	2006	16715101
differential requirements for soluble and transmembrane tumor necrosis factor in the immunological control of primary and secondary listeria monocytogenes infection.	the relative contributions of transmembrane tumor necrosis factor (memtnf) and soluble tumor necrosis factor (soltnf) in innate and adaptive immunity are poorly defined. we examined the capacities of wild-type (wt) mice, tnf-/- mice, and memtnf mice, which express only transmembrane tnf, to control primary and secondary listeria monocytogenes infections. soluble tnf was not required for induction or maintenance of protective immunity against a low-dose (200-cfu) listeria infection. in contrast t ...	2006	16714545
the specific and essential role of mavs in antiviral innate immune responses.	the mitochondrial antiviral signaling protein (mavs) mediates the activation of nfkappab and irfs and the induction of interferons in response to viral infection. in vitro studies have also suggested that mavs is required for interferon induction by cytosolic dna, but the in vivo evidence is lacking. by generating mavs-deficient mice, here we show that loss of mavs abolished viral induction of interferons and prevented the activation of nfkappab and irf3 in multiple cell types, except plasmacyto ...	2006	16713980
listeria monocytogenes: a multifaceted model.	the opportunistic intracellular pathogen listeria monocytogenes has become a paradigm for the study of host-pathogen interactions and bacterial adaptation to mammalian hosts. analysis of l. monocytogenes infection has provided considerable insight into how bacteria invade cells, move intracellularly, and disseminate in tissues, as well as tools to address fundamental processes in cell biology. moreover, the vast amount of knowledge that has been gathered through in-depth comparative genomic anal ...	2006	16710323
overexpression of prfa leads to growth inhibition of listeria monocytogenes in glucose-containing culture media by interfering with glucose uptake.	listeria monocytogenes strains expressing high levels of the virulence regulator prfa (mutant prfa* or wild-type prfa) show strong growth inhibition in minimal media when they are supplemented with glucose but not when they are supplemented with glucose-6-phosphate compared to the growth of isogenic strains expressing low levels of prfa. a significantly reduced rate of glucose uptake was observed in a prfa*-overexpressing strain growing in lb supplemented with glucose. comparative transcriptome ...	2006	16707681
fitness of human enteric pathogens on plants and implications for food safety.	the continuous rise in the number of outbreaks of foodborne illness linked to fresh fruit and vegetables challenges the notion that enteric pathogens are defined mostly by their ability to colonize the intestinal habitat. this review describes the epidemiology of produce-associated outbreaks of foodborne disease and presents recently acquired knowledge about the behavior of enteric pathogens on plants, with an emphasis on salmonella enterica, escherichia coli o157:h7, and listeria monocytogenes. ...	2006	16704355
a comparison of selected methods for measuring the virulence properties of listeria spp.	the comparative ability of different methods to assess virulence of listeria species was investigated in ten listeria strains. all strains were initially subjected to pulsed-field gel electrophoresis analysis to determine their relatedness. virulence characteristics were subsequently tested for by (i) determining the presence of six virulence genes by polymerase chain reaction; (ii) testing for the production of listeriolysin o, phosphatidylcholine phospholipase c, and phosphatidylinositol-speci ...	2006	16699580
dynamic modeling of listeria monocytogenes growth in pasteurized milk.	the development and validation of a dynamic model for predicting listeria monocytogenes growth in pasteurized milk stored at both static and dynamic temperature conditions.	2006	16696676
efficiency of electrolyzed oxidizing water on reducing listeria monocytogenes contamination on seafood processing gloves.	food processing gloves are typically used to prevent cross-contamination during food preparation. however, gloves can be contaminated with microorganisms and become a source of contamination. this study investigated the survival of listeria monocytogenes on gloves and determined the efficacy of electrolyzed oxidizing (eo) water for reducing l. monocytogenes contamination on seafood processing gloves. three types of reusable gloves (natural rubber latex, natural latex, and nitrile) and two types ...	2006	16690154
genetic relatedness between listeria monocytogenes isolates from seafood and humans using pfge and rep-pcr.	listeria monocytogenes has been isolated from catfish and various non-catfish seafoods. despite progress that was made to understand the relationship between l. monocytogenes isolated from seafood and humans, no study has emphasized the genetic relatedness between catfish and non-catfish seafood and human isolates. the objectives of this study were to (1) investigate the genetic relationship between l. monocytogenes isolates from catfish, non-catfish seafood and humans using pulsed-field gel ele ...	2006	16690152
surrogates for validation of electron beam irradiation of foods.	the aim of this study was to identify a potential surrogate to describe the radiation sensitivity of the most common pathogens encountered in fruits. three pathogens: escherichia coli o157:h7 933, listeria monocytogenes atcc 51414, and salmonella poona, and five non-pathogens: e. coli k-12 mg1655, listeria innocua seeliger 1983 (nrrl b-33003 and nrrl b-33014), enterobacter aerogenes, and salmonella lt2 were inoculated (populations of 10(7)-10(9) cfu/ml) into model food systems (10% w/w gelatin) ...	2006	16690150
escherichia coli interactions with acanthamoeba: a symbiosis with environmental and clinical implications.	the ability of acanthamoeba to feed on gram-negative bacteria, as well as to harbour potential pathogens, such as legionella pneumophila, coxiella burnetii, pseudomonas aeruginosa, vibrio cholerae, helicobacter pylori, listeria monocytogenes and mycobacterium avium, suggest that both amoebae and bacteria are involved in complex interactions, which may play important roles in the environment and in human health. in this study, acanthamoeba castellanii (a keratitis isolate belonging to the t4 geno ...	2006	16687585
identification, subtyping and virulence determination of listeria monocytogenes, an important foodborne pathogen.	listeria monocytogenes is an opportunistic intracellular pathogen that has become an important cause of human foodborne infections worldwide. given its close relationship to other listeria species and its tendency to produce non-specific clinical symptoms, the availability of rapid, sensitive and specific diagnostic tests for the differentiation of l. monocytogenes from other listeria species is helpful for selecting appropriate treatment regimens. in addition, with l. monocytogenes comprising a ...	2006	16687581
identification of small hfq-binding rnas in listeria monocytogenes.	the rna-binding protein hfq plays important roles in bacterial physiology and is required for the activity of many small regulatory rnas in prokaryotes. we have previously shown that hfq contributes to stress tolerance and virulence in the gram-positive human pathogen listeria monocytogenes. in the present study, we performed coimmunoprecipitations followed by enzymatic rna sequencing to identify hfq-binding rna molecules in l. monocytogenes. the approach resulted in the discovery of three small ...	2006	16682563
listeria monocytogenes protein p60 affects hemolytic activity and uptake of bacteria by macrophages.	bacillus subtilis strains expressing listeriolysin o (llo) and simultaneously llo and p60 protein were constructed. the effect of p60 protein on hemolytic activity and on the invasion of professional phagocytes was demonstrated in the absence of other virulence factors of l. monocytogenes. the hemolytic activity of llo in the presence of p60 protein decreased which indicates that p60 promoted adhesion and subsequent invasion of professional phagocytes.	2005	16681150
bactericidal effects of cao (scallop-shell powder) on foodborne pathogenic bacteria.	this study was investigated the bactericidal effects of calcium oxide (cao) on three common foodborne pathogenic bacteria: escherichia coli, listeria monocytogenes, and salmonella typhimurium. each bacteria level was determined in a cao solution (0.01, 0.03, 0.05, 0.10, 0.15, and 0.20% [w/v]) exposed for either 15 sec, 30 sec, 1 min, 2 min, 3 min, 5 min, 10 min, or 30 min. all three bacteria were not greatly affected by cao solutions at concentrations of 0.01 and 0.03%, however, the decline of e ...	2006	16681035
the bacterial quality of red meat and offal in casablanca (morocco).	the present study aimed to evaluate the bacteriological quality of beef (n = 52), lamb (n = 52) and beef offal (n = 52) marketed in casablanca, morocco. meat and offal samples (n = 156), were collected randomly from butcheries, supermarkets, and slaughterhouses. two sampling periods were considered, one during the hot season and the second one during the cold season. the samples were analyzed for the presence of the following bacteria: escherichia coli, coagulase-positive staphylococcus, clostri ...	2006	16676376
listeric meningoencephalomyelitis in a cougar (felis concolor): characterization by histopathologic, immunohistochemical, and molecular methods.	listeria monocytogenes has been recognized as an important food-borne pathogen in animals. records of the disease caused by this bacterium in large felids are, however, rare. the nervous form of listeriosis was diagnosed in a 12-year-old male cougar (felis concolor) with a several-day history of neurologic disease characterized by excess salivation, head pressing, and circling that progressed to recumbency and death. microscopically, the main alteration in the brain and spinal cord was a variabl ...	2006	16672590
role of efflux pumps in adaptation and resistance of listeria monocytogenes to benzalkonium chloride.	in this study, potential mechanisms underlying resistance and adaptation to benzalkonium chloride (bc) in listeria monocytogenes were investigated. two groups of strains were studied. the first group consisted of strains naturally sensitive to bc which could be adapted to bc. the second group consisted of naturally resistant strains. for all adapted isolates, there was a correlation between the resistance to bc and ethidium bromide, but this was not the case for the naturally resistant isolates. ...	2006	16672496
control of listeria spp. by competitive-exclusion bacteria in floor drains of a poultry processing plant.	in previous studies workers determined that two lactic acid bacterium isolates, lactococcus lactis subsp. lactis c-1-92 and enterococcus durans 152 (competitive-exclusion bacteria [ce]), which were originally obtained from biofilms in floor drains, are bactericidal to listeria monocytogenes or inhibit the growth of l. monocytogenes both in vitro and in biofilms at 4 to 37 degrees c. we evaluated the efficacy of these isolates for reducing listeria spp. contamination of floor drains of a plant in ...	2006	16672472
listeriosis due to infection with a catalase-negative strain of listeria monocytogenes.	a strain of listeria monocytogenes recovered from blood and cerebrospinal fluid had no detectable catalase activity, a characteristic used for primary identification. the sporadic occurrence of pathogenic catalase-negative strains highlights the need for a reconsideration of diagnostic criteria and questions the role of catalase in the pathogenesis of listeria infection.	2006	16672441
cytokine modulation of the innate immune response in feline immunodeficiency virus-infected cats.	in vitro data suggest that innate immune function in human immunodeficiency virus type 1-infected patients is compromised; however, in vivo studies are lacking. feline immunodeficiency virus (fiv) infection in cats provides an excellent model to explore innate immune function in vivo. the innate response against listeria monocytogenes is well understood, making it a useful immune probe.	2006	16652280
elemental analysis of the mycobacterium avium phagosome in balb/c mouse macrophages.	using a hard x-ray microprobe, we showed recently that in unstimulated peritoneal macrophages from c57bl/6 mice, the phagosome of pathogenic mycobacteria (mycobacterium tuberculosis and mycobacterium avium) can accumulate iron. we expanded our studies to the m. avium infection of peritoneal macrophages of balb/c mice that show a similar degree of m. tuberculosis and m. avium-related chronic disease, but a higher susceptibility towards other intracellular pathogens such as listeria monocytogenes, ...	2006	16650826
bacterial entry into cells: a role for the endocytic machinery.	increasing evidence indicates that pathogens have evolved highly efficient strategies to induce their internalization within host cells. viruses and bacteria express and expose on their surface, molecules that mimic endogenous ligands to cell receptors, thereby inducing specific intracellular signalling cascades. more recently it has become clear that, as most viruses, bacteria can enter cells via the clathrin-mediated pathway, indicating a key role for endocytosis in pathogens entry into cells. ...	2006	16650411
cellular accumulation and activity of quinolones in ciprofloxacin-resistant j774 macrophages.	ciprofloxacin is the substrate for a multidrug resistance-related protein (mrp)-like multidrug transporter in j774 mouse macrophages, which also modestly affects levofloxacin but only marginally affects garenoxacin and moxifloxacin (j.-m. michot et al., antimicrob. agents chemother. 49:2429-2437, 2005). two clones of ciprofloxacin-resistant cells were obtained by a stepwise increase in drug concentration (from 34 to 51 to 68 mg/liter) in the culture fluid. compared to wild-type cells, ciprofloxa ...	2006	16641436
leucocins 4010 from leuconostoc carnosum cause a matrix related decrease in intracellular ph of listeria monocytogenes.	a mixed culture of single cells of listeria monocytogenes and the bacteriocin producing leuconostoc carnosum 4010 showed growth inhibition of l. monocytogenes, although the intracellular ph (phi) of l. monocytogenes followed by fluorescence ratio imaging microscopy was not affected. furthermore, l. monocytogenes was exposed to the bacteriocins leucocins 4010 and nisin either in a liquid filled chamber or on the surface of an agar containing bacteriocins. both bacteriocins caused dissipation of t ...	2006	16640575
roche/biotecon diagnostics lightcycler foodproof l. monocytogenes detection kit in combination with shortprep foodproof ii kit. performance-tested method 070401.	a method was developed for the detection of l. monocytogenes in food based on real-time polymerase chain reaction (pcr). this advanced pcr method was designed to reduce the time needed to achieve results from pcr reactions and to enable the user to monitor the amplification of the pcr product simultaneously, in real-time. after dna isolation using the roche/biotecon diagnostics shortprep foodproof ii kit (formerly called listeria shortprep kit) designed for the rapid preparation of l. monocytoge ...	2006	16640287
unidirectional development of cd8+ central memory t cells into protective listeria-specific effector memory t cells.	three distinct subsets of antigen-experienced cd8(+) t cells have been identified so far: short-living effector t cells (t(ec)) and two long-living subsets, described as central (t(cm)) and effector memory (t(em)) t cells. the lineage relationships of these subpopulations as well as their involvement in protection have not yet been conclusively determined. we recently described a novel marker combination (cd127 and cd62l) to identify all three major cd8(+) t cell subsets in mice infected with li ...	2006	16637009
quantitative and simultaneous detection of four foodborne bacterial pathogens with a multi-channel spr sensor.	we report the quantitative and simultaneous detection of four species of bacteria, escherichia coli o157:h7, salmonella choleraesuis serotype typhimurium, listeria monocytogenes, and campylobacter jejuni, using an eight-channel surface plasmon resonance (spr) sensor based on wavelength division multiplexing. detection curves showing spr response versus analyte concentration were established for each species of bacteria in buffer at ph 7.4, apple juice at native ph 3.7, and apple juice at an adju ...	2006	16635568
coexpression of virulence and fosfomycin susceptibility in listeria: molecular basis of an antimicrobial in vitro-in vivo paradox.	discrepancies between resistance in vitro and therapeutic efficacy in vivo are generally attributed to failure of laboratory susceptibility tests to reflect an antibiotic's pharmacokinetic or pharmacodynamic properties. we show here that this phenomenon can result from differential in vitro-in vivo expression of bacterial determinants of antibiotic susceptibility. we found that an in vivo-induced virulence factor, hpt, also mediates uptake of fosfomycin in listeria monocytogenes. these bacteria ...	2006	16633349
optimization of the components concentrations of the lactoperoxidase system by rsm.	the aim of this work was to use response surface methodology (rsm) approach, a statistical mathematical tool, to model effects and interactions of glucose oxidase (god), glucose, lactoperoxidase (lpo) and ph-values on the thiocyanate (scn-) peroxidation, to determine the best concentrations of lactoperoxidase system (lp-s) components in order to obtain maximal scn- peroxidation and so to enhance the lp-s antibacterial effects.	2006	16630004
effect of environmental stresses on antibody-based detection of escherichia coli o157:h7, salmonella enterica serotype enteritidis and listeria monocytogenes.	to study the reaction patterns of selected antibodies to escherichia coli o157:h7, salmonella enterica serotype enteritidis and listeria monocytogenes cells exposed to various environmental stresses.	2006	16630002
interactions of nisin with glutathione in a model protein system and meat.	loss of nisin activity in meat has been ascribed, in part, to the formation of a nisin-glutathione adduct. activity is lost more quickly in raw meat than in cooked meat, and this has been taken as evidence that the reaction is enzyme mediated. formation of the nisin-glutathione adduct has been confirmed but is shown not to be enzyme mediated. retention of activity in cooked meat is shown to be due to the loss of free sulfhydryl groups during cooking as a result of the reaction of glutathione wit ...	2006	16629047
prevalence and concentration of listeria monocytogenes in sliced ready-to-eat meat products in the hellenic retail market.	the aim of this work was to estimate the prevalence and concentration of listeria monocytogenes in packaged precut (slices or cubes) ready-to-eat (rte) meat products available in the hellenic retail market. samples of these rte meat products (n = 209) were taken from local supermarkets during a 3-month period and analyzed for the presence of l. monocytogenes with an automated enzymatic qualitative immunoassay followed by biochemical confirmation of positive results. the concentration of the path ...	2006	16629044
comparison of listeria monocytogenes virulence in a mouse model.	listeriosis results from exposure to the foodborne pathogen listeria monocytogenes. although many different strains of l. monocytogenes are isolated from food, no definitive tests currently predict which isolates are most virulent. the objectives of this study were to address two major data gaps for risk assessors, variability among l. monocytogenes strains in pathogenicity and virulence. strains used in our monkey clinical trial or additional food isolates were evaluated for their virulence and ...	2006	16629027
molecular typing to trace listeria monocytogenes isolated from cold-smoked fish to a contamination source in a processing plant.	in this study, listeria monocytogenes contamination in a cold-smoked fish processing plant in osaka, japan, was examined from 2002 to 2004. a total of 430 samples were collected and divided into five categories: raw fish, materials during processing, processing equipment, environment, and finished products. a total of 59 finished products were examined throughout this study. l. monocytogenes was isolated from four of these samples during summer and autumn but was not found during winter or sprin ...	2006	16629026
formation of biofilm at different nutrient levels by various genotypes of listeria monocytogenes.	strains of listeria monocytogenes differ in their ability to form biofilms. the objectives of this study were to determine whether genetically related strains have similar biofilm-forming capacities and what effect nutrient concentration has on the ability of different strains to produce biofilms. biofilms of 30 strains of l. monocytogenes, obtained from a variety of sources were grown on stainless steel in tryptic soy broth (tsb) or in a 1:10 dilution of tsb (dtsb) for 24 h at 32 degrees c. the ...	2006	16629025
growth of listeria monocytogenes in fresh-cut coconut as affected by storage conditions and inoculum size.	in this study, the effects of packaging atmosphere (air and modified atmosphere, 65% n2, 30% co2, and 5% o2), temperature (2, 4, 8, and 12 degrees c) and inoculum size (low inoculum, 102 cfu/g; high inoculum, 5 x 10(5) cfu/g) on the growth of listeria monocytogenes in minimally processed coconut were investigated. growth data were fitted to the gompertz equation, and the sanitary risk time (the time, in days, necessary to observe an increase of 2 log cfu/g in the level of the pathogen) was also ...	2006	16629024
prevalence and typing of listeria monocytogenes in raw catfish fillets.	raw channel catfish fillets collected from three processing plants during four time periods were tested for the presence of listeria species. listeria monocytogenes was the predominant listeria species found in these catfish fillets, with 25 to 47% prevalence. other listeria species, such as l. welshimeri, l. innocua, l. ivanovii, l. grayi, and l. seeligeri, were also found. l. monocytogenes isolates were further fingerprinted by a repetitive element pcr. forty distinctive electrophoretic types ...	2006	16629023
death of salmonella, escherichia coli o157:h7, and listeria monocytogenes in shelf-stable, dairy-based, pourable salad dressings.	the objectives of this study were to determine the death rates of salmonella, escherichia coli o157:h7, and listeria monocytogenes in three commercially manufactured full-fat ranch salad dressings, three reduced-fat ranch salad dressings, two full-fat blue cheese salad dressings, and two reduced-fat blue cheese salad dressings and to affirm the expectation that these dressings do not support the growth of these pathogens. the respective initial ph values of the four types of shelf-stable, dairy- ...	2006	16629022
validation of a traditional italian-style salami manufacturing process for control of salmonella and listeria monocytogenes.	italian-style salami batter (formulated with pork shoulder) was inoculated with ca. 7.0 log cfu/g of either salmonella or listeria monocytogenes. salami links (55-mm cellulose casings) were fermented at 30 degrees c for 24, 40, or 72 h and then dried to target moisture/protein ratios (mprs) of 1.9:1 or 1.4:1. links were sampled after fermentation (24, 40, and 72 h) and after combined fermentation-drying treatments (mprs of 1.9:1 and 1.4:1 for all fermentation periods), and microbiological and pr ...	2006	16629021
enhanced bacterial clearance and sepsis resistance in caspase-12-deficient mice.	caspases function in both apoptosis and inflammatory cytokine processing and thereby have a role in resistance to sepsis. here we describe a novel role for a caspase in dampening responses to bacterial infection. we show that in mice, gene-targeted deletion of caspase-12 renders animals resistant to peritonitis and septic shock. the resulting survival advantage was conferred by the ability of the caspase-12-deficient mice to clear bacterial infection more efficiently than wild-type littermates. ...	2006	16625199
macrophage-activation inhibitor factor from l5178y murine lymphoma and formation of hepatic abscesses in balb/c mice.	normal mice are naturally resistant to hepatic abscesses produced by listeria monocytogenes. a macrophage-activation inhibitor factor (maif) isolated from the cell-free ascitic fluid of l5178y lymphoma-bearing mice inhibited the lipopolysaccharide-induced production of nitric oxide (no) by the macrophages. because macrophages are also involved in the immune response towards l. monocytogenes, the present study had the objective of investigating whether maif was also capable of allowing l. monocyt ...	2006	16624645
how the bacterial pathogen listeria monocytogenes mediates the switch from environmental dr. jekyll to pathogenic mr. hyde.		2006	16622185
exploring the role of the ctl epitope region of listeriolysin o in the pathogenesis of listeria monocytogenes.	listeria monocytogenes is a facultative intracellular bacterial pathogen responsible for severe opportunistic infections in humans and animals. the secreted cholesterol-dependent cytolysin, listeriolysin o (llo), mediates phagosomal escape and allows bacterial growth in the cytosol of infected cells. in order to identify new llo determinants participating in bacterial pathogenesis, this study focused on a major target of llo proteolytic cleavage in vitro, the ctl epitope region (residues 91-99). ...	2006	16622046
serine protease inhibitor 6 protects cytotoxic t cells from self-inflicted injury by ensuring the integrity of cytotoxic granules.	how cytotoxic t lymphocytes (ctls) kill intracellular pathogens without killing themselves has been a recurring question ever since their discovery. by using mice deficient in serine protease inhibitor 6 (spi6), we show that by inhibiting granzyme b (grb), spi6 protects ctls from self-inflicted injury. infection with either lymphocytic choriomeningitis virus (lcmv) or listeria monocytogenes (lm) revealed increased apoptosis and diminished survival of spi6 knockout (ko) ctls, which was cell auton ...	2006	16618603
detection of genes encoding virulence factors and bacteriocins in fecal enterococci of poultry in portugal.	seventy-six enterococcus isolates (43 e. faecalis, 30 e. faecium, two e. durans, and one e. hirae) recovered from fecal samples of poultry in a slaughterhouse (one isolate per fecal sample and one fecal sample per lot of animals) were studied for bacteriocin production and for the presence of genes encoding bacteriocins and virulence factors. the presence of genes encoding virulence factors (cpd, gee, fsr, ace, agg, and esp) and bacteriocins (enta, entb, entp, entq, entas-48, entl50a/b, cyl, and ...	2006	16617984
the mogr transcriptional repressor regulates nonhierarchal expression of flagellar motility genes and virulence in listeria monocytogenes.	flagella are surface structures critical for motility and virulence of many bacterial species. in listeria monocytogenes, mogr tightly represses expression of flagellin (flaa) during extracellular growth at 37 degrees c and during intracellular infection. mogr is also required for full virulence in a murine model of infection. using in vitro and in vivo infection models, we determined that the severe virulence defect of mogr-negative bacteria is due to overexpression of flaa. specifically, overp ...	2006	16617375
cytoplasmic listeria monocytogenes stimulates ifn-beta synthesis without requiring the adapter protein mavs.	the mitochondria-associated adapter protein mavs (also called ips-1, visa or cardif, designated mavs for reasons of simplicity in our manuscript) relays signals from cytoplasmic sensors of viral rna to the irf3 kinase complex and the interferon-beta (ifn-beta) gene. using sirna-mediated knock-down in macrophages we show that ifn-beta synthesis in response to transfected, intracellular double-stranded rna (dsrna), a pathogen-associated molecular pattern of viruses, is decreased in absence of mavs ...	2006	16616525
effect of temperature on synthesis of polyphosphates in yersinia pseudotuberculosis and listeria monocytogenes under starvation conditions.	it was found that at low temperature (6-8 degrees c) in the absence of nitrogen supply and at the presence of phosphate ions in the medium, yersinia pseudotuberculosis and listeria monocytogenes are able to actively synthesize reserve substances as polyphosphates. most of the bacterial polyphosphates are alkali-soluble, especially at the preliminary stage of cell growth (lag-phase). this is proved by electron microscopic studies of ultrastructure of model microorganisms. during a long starvation ...	2006	16615864
redox polymer and probe dna tethered to gold electrodes for enzyme-amplified amperometric detection of dna hybridization.	the detection of nucleic acids based upon recognition surfaces formed by co-immobilization of a redox polymer mediator and dna probe sequences on gold electrodes is described. the recognition surface consists of a redox polymer, [os(2,2'-bipyridine)2(polyvinylimidazole)(10)cl](+/2+), and a model single dna strand cross-linked and tethered to a gold electrode via an anchoring self-assembled monolayer (sam) of cysteamine. hybridization between the immobilized probe dna of the recognition surface a ...	2006	16615783
membrane perforations inhibit lysosome fusion by altering ph and calcium in listeria monocytogenes vacuoles.	listeria monocytogenes (lm) evade microbicidal defences inside macrophages by secreting a pore-forming cytolysin listeriolysin o (llo), which allows lm to escape vacuoles. llo also inhibits lm vacuole fusion with lysosomes, which indicates llo alters vacuole chemistry prior to release of lm into cytoplasm. using fluorescent probes to measure membrane permeability, calcium and ph, we identified small membrane perforations in vacuoles containing wild-type but not llo-deficient (hly-) lm. the small ...	2006	16611227
cytosolic recognition of flagellin by mouse macrophages restricts legionella pneumophila infection.	to restrict infection by legionella pneumophila, mouse macrophages require naip5, a member of the nucleotide-binding oligomerization domain leucine-rich repeat family of pattern recognition receptors, which detect cytoplasmic microbial products. we report that mouse macrophages restricted l. pneumophila replication and initiated a proinflammatory program of cell death when flagellin contaminated their cytosol. nuclear condensation, membrane permeability, and interleukin-1beta secretion were trig ...	2006	16606669
virulence phenotyping and molecular characterization of a low-pathogenicity isolate of listeria monocytogenes from cow's milk.	a low-pathogenicity isolate of listeria monocytogenes from cow's milk, as screened in mouse and chicken embryonated egg models, was examined for virulence-related phenotypic traits. corresponding virulence genes (iap, prfa, plca, hly, mpl, acta, plcb, inla and inlb) were compared with l. monocytogenes reference strains 10403s and egd to elucidate the possible molecular mechanisms of low virulence. although l. monocytogenes h4 exhibited similar patterns to strain 10403s in terms of hemolytic acti ...	2006	16604266
a comparison of listeria monocytogenes serovar 4b isolates of clinical and food origin in austria by automated ribotyping and pulsed-field gel electrophoresis.	in this study, two typing methods, automated ribotyping and pulsed-field gel electrophoresis (pfge), were evaluated for the subtyping of listeria monocytogenes serotype 4b. the strains originated from patients and food samples collected in austria during 2001-2005 and from europe and north america in the world health organization collaborative study on the subtyping of this species. the largest group of austrian clinical isolates was of the same pfge subtype as those isolated from foodborne outb ...	2006	16602989
canadian listeriosis reference service.	listeria monocytogenes, a psychrotrophic organism capable of growing at refrigeration temperatures, is of major concern in extended shelf life, refrigerated foods. considering that as much as 80-90% of human listeriosis cases are linked to the ingestion of contaminated food, human cases are predominantly seen in high-risk individuals, including organ-transplant recipients, patients with aids and hiv-infected individuals, pregnant women, cancer patients, and the elderly. in 2001, the canadian lis ...	2006	16602988
pulsenet usa: a five-year update.	pulsenet usa is the molecular surveillance network for foodborne infections in the united states. since its inception in 1996, it has been instrumental in detection, investigation and control of numerous outbreaks caused by shiga toxin-producing escherichia coli o157:[h7] (stec o157), salmonella enterica, listeria monocytogenes, shigella spp., and campylobacter. this paper describes the current status of the network, including the methodologies used and its future possibilities. the currently pr ...	2006	16602975
the development of rapid fluorescence-based immunoassays, using quantum dot-labelled antibodies for the detection of listeria monocytogenes cell surface proteins.	listeria monocytogenes is an important food-borne pathogen with an extremely high mortality rate (approximately 30%). therefore, a highly sensitive, reproducible and rapid assay for its detection is vital. l. monocytogenes cells employ two surface bound proteins, internalin a (inla) and internalin b (inlb) to promote invasion into host cells. recombinant forms of both proteins were previously cloned and expressed in escherichia coli. in this paper we describe how the inlb protein was sub-divided ...	2006	16600361
inactivation of salmonella typhimurium and listeria monocytogenes using high-pressure treatments: destruction or sublethal stress?	to investigate potential resuscitation of listeria monocytogenes and salmonella typhimurium after high hydrostatic pressure treatments.	2006	16599988
bacteriocin production, plasmid content and plasmid location of enterocin p structural gene in enterococci isolated from food sources.	to characterize bacteriocin production, antimicrobial spectrum and plasmid content in bacteriocinogenic enterococci from foods.	2006	16599984
analysis of the murein of a listeria monocytogenes egd mutant lacking functional penicillin binding protein 5 (pbp5).	cells of a mutant of listeria monocytogenes lacking functional pbp5, an enzyme with dd-carboxypeptidase activity, make thicker cells walls. in this study we show that the muropeptide profile of the mutant, obtained after hplc analysis of a muramidase digest of cell wall murein, differs from that for the wild type strain. the main differences embrace strongly reduced disaccharide-tripeptide content, strongly increased amounts of pentapeptide-containing muropeptides and a shift in profile from les ...	2005	16599308
novel luciferase reporter system for in vitro and organ-specific monitoring of differential gene expression in listeria monocytogenes.	in this paper we describe construction of a luciferase-based vector, ppl2lux, and use of this vector to study gene expression in listeria monocytogenes. ppl2lux is a derivative of the listerial integration vector ppl2 and harbors a synthetic luxabcde operon encoding a fatty acid reductase complex (luxcde) involved in synthesis of the fatty aldehyde substrate for the bioluminescence reaction catalyzed by the luxab luciferase. we constructed ppl2lux derivatives in which the seca and hlya promoters ...	2006	16597994
assessment of the roles of luxs, s-ribosyl homocysteine, and autoinducer 2 in cell attachment during biofilm formation by listeria monocytogenes egd-e.	luxs is responsible for the production of autoinducer 2 (ai-2), which is involved in the quorum-sensing response of vibrio harveyi. ai-2 is found in several other gram-negative and gram-positive bacteria and is therefore considered a good candidate for an interspecies communication signal molecule. in order to determine if this system is functional in the gastrointestinal pathogen listeria monocytogenes egd-e, an ai-2 bioassay was performed with culture supernatants. the results indicated that t ...	2006	16597969
bioenergetic mechanism for nisin resistance, induced by the acid tolerance response of listeria monocytogenes.	this study examined the bioenergetics of listeria monocytogenes, induced to an acid tolerance response (atr). changes in bioenergetic parameters were consistent with the increased resistance of atr-induced (atr(+)) cells to the antimicrobial peptide nisin. these changes may also explain the increased resistance of l. monocytogenes to other lethal factors. atr(+) cells had lower transmembrane ph (deltaph) and electric potential (deltapsi) than the control (atr(-)) cells. the decreased proton moti ...	2006	16597957
construction and analysis of fractional multifactorial designs to study attachment strength and transfer of listeria monocytogenes from pure or mixed biofilms after contact with a solid model food.	the aim of this study was to establish which of seven factors influence the adhesion strength and hence bacterial transfer between biofilms containing listeria monocytogenes (pure and two-species biofilms) and tryptone soya agar (tsa) as a solid organic surface. the two-species biofilms were made of l. monocytogenes and one of the following species of bacteria: the nonpathogenic organisms kocuria varians, pseudomonas fluorescens, and staphylococcus sciuri and ccl 63, an unidentified gram-negativ ...	2006	16597925
dependence of the lethal effect of pore-forming haemolysins of gram-positive bacteria on cytolytic activity.	among bacterial haemolysins, cholesterol-dependent cytolysins (cdcs) produced by various gram-positive bacteria are known to exhibit a lethal activity in mice. in this study, recombinant cdcs of streptolysin o, pneumolysin, ivanolysin o, listeriolysin o and several listeriolysin o mutants were constructed and the relationship between cytolytic activity and the lethal activity of each recombinant protein in mice was examined. specific activity for cytolysis was determined by a quantitative haemol ...	2006	16585635
co-detection of bartonella henselae, borrelia burgdorferi, and anaplasma phagocytophilum in ixodes pacificus ticks from california, usa.	presence of bartonella dna was explored in 168 questing adult ixodes pacificus ticks from santa cruz county, california. bartonella henselae type i dna was amplified from 11 ticks (6.55%); previously, two (1.19%) were found to be infected with borrelia burgdorferi and five (2.98%) with anaplasma phagocytophilum. detection of b. henselae was not dependent on co-infection. the present study offers additional evidence that ixodes spp. ticks may act as hosts and possibly vectors for b. henselae.	2006	16584332
listeria monocytogenes: silage, sandwiches and science.	listeria monocytogenes is amongst the most intriguing and well studied of the pathogenic bacteria. however, the understanding and perspective one has of l. monocytogenes depends to a large extent on the microbiological issues with which one is faced as a part of your professional duties. the focus of the veterinary clinician or investigator is likely to be foremost on the neurologic (circling disease) and reproductive diseases l. monocytogenes causes. to the food microbiologist, the principal co ...	2005	16583783
recombinant escherichia coli expressing invasin targets the peyer's patches: the basis for a bacterial formulation for oral vaccination.	we have investigated the tropism of nonpathogenic recombinant invasive escherichia coli in the gastrointestinal tract and the efficacy of this invasive e. coli as an oral vaccine for cancer immunotherapy. e. coli expressing invasin from yersinia pseudotuberculosis selectively invade nonphagocytic cells in which beta(1)-integrin is expressed and accessible. following internalization the e. coli are degraded in the phagosome. coexpression of listeriolysin o (llo) mediates release of the content of ...	2006	16581299
associations among listeria monocytogenes genotypes and distinct clinical manifestations of listeriosis in cattle.	to determine whether specific strains of listeria monocytogenes, as determined by genetic characteristics and virulence phenotypes, were associated with distinct clinical manifestations of listeriosis in cattle and thus may potentially have tissue specificity.	2006	16579754
[investigation of relationships between marine diatoms and the bacterium listeria monocytogenes].	relationships between marine diatoms and the bacterium listeria monocytogenes have been studied by routine algological methods and high-resolution video-enhanced differential interference contrast light microscopy. the study showed that the relationship between the listeria and the benthic diatom navicula sp. has a parasitic character, whereas the relationship between the listeria and the planktonic diatom phaeodactylum tricornutum is protocooperative.	2006	16579449
n-3 pufa fail to affect in vivo, antigen-driven cd8+t-cell proliferation in the spleen of naïve mice.	one of the most frequently reported immunomodulatory actions of n-3 pufa is their ability to diminish in vitro lymphocyte proliferation. the purpose of this study was to determine if n-3 pufa intake affects the kinetics or magnitude of the antigen-driven expansion of cd8(+)t-lymphocytes in vivo. in this study we utilized a well-characterized model of t-cell immunity (i.e. infection with the intracellular bacterium, listeria monocytogenes). weanling balb/c mice were fed one of two experimental di ...	2006	16571165
bac 32, a novel bacteriocin widely disseminated among clinical isolates of enterococcus faecium.	a total of 636 vancomycin-resistant enterococcus faecium (vre) isolates that had been obtained between 1994 and 1999 from the medical school hospital of the university of michigan, ann arbor, were tested for bacteriocin production. two hundred seventy-seven (44%) of the strains were bacteriocinogenic; and 193 of these exhibited activity against enterococcus faecium, enterococcus hirae, and enterococcus durans. strain vre200 harbors the highly efficient conjugative gentamicin resistance plasmid p ...	2006	16569830
in vivo bactofection: listeria can function as a dna-cancer vaccine.	the development of an effective therapeutic vaccine to induce cancer-specific immunity remains an unsolved yet pressing priority requiring novel vaccine strategies. here we have generated a series of vaccines in which bacteria deliver a plasmid encoding a tumor antigen under the control of a mammalian promoter in an attempt to induce an antitumor immune response. utilizing a plasmid release mechanism involving the suicide of the carrier bacteria, we were able to engineer listeria monocytogenes t ...	2006	16569193
multiplex real-time single nucleotide polymorphism detection and quantification by quencher extension.	multiplex quencher extension (multiplex-qext) is a novel closed tube single-step method for detection and quantification of several single nucleotide polymorphisms (snps) simultaneously. the principle of multiplex-qext is that 5' reporter-labeled probes are 3' single-base-extended with tamra dideoxy nucleotides if the respective snp alleles are present. tamra can serve as either an energy acceptor (quencher-based detection) or donor [fluorescence resonance energy transfer (fret)-based detection] ...	2006	16568821
secondary memory cd8+ t cells are more protective but slower to acquire a central-memory phenotype.	the formation of memory cd8 t cells is an important goal of vaccination. however, although widespread use of booster immunizations in humans generates secondary and tertiary cd8 t cell memory, experimental data are limited to primary cd8 t cell memory. here, we show that, compared with primary memory cd8 t cells, secondary memory cd8 t cells exhibit substantially delayed conversion to a central-memory phenotype, as determined by cd62l expression and interleukin (il)-2 production. this delayed co ...	2006	16567385
autoinducer-2 bioassay is a qualitative, not quantitative method influenced by glucose.	autoinducer-2 (ai-2) is a cell-to-cell signaling molecule which is thought to be utilized for quorum sensing processes by a variety of prokaryotic species. this molecule is usually detected using a so-called autoinducer bioassay, which relies on the ability of a vibrio harveyi reporter strain to produce light in response to ai-2. however, as previously reported, the presence of glucose in the sample can inhibit the bioluminescence of the reporter strain, a fact that is often ignored by investiga ...	2006	16564586
specificity of acquired resistance produced by immunization with listeria monocytogenes and listeria fractions.	mice were immunized with 1.0 mg of an attenuated strain of listeria monocytogenes to determine the period of protection afforded by this strain when the mice were challenged intravenously with 5 mld of listeria. protection appeared 2 days after immunization and was still apparent 4 weeks after immunization. if the challenge dose was decreased to 1 mld, protection was apparent at 10 weeks. mice immunized with a comparable dose of mycobacterial cells and challenged intravenously with 1 mld of list ...	1969	16562159
susceptibility of the sage brush vole, lagurus curtatus, to listeria monocytogenes.		1965	16562034
the flagellation of listeria monocytogenes.		1944	16560812
induction of resistance by listeria monocytogenes cell wall fraction.	a crude cell wall fraction of listeria monocytogenes was prepared by sonic disruption and differential centrifugation of viable, washed cultures. when injected into mice, this sterile, crude cell wall fraction protected mice against an intraperitoneal challenge with 18 to 85 50% mean lethal dose of l. monocytogenes. resistance was greatly enhanced when bacterial endotoxin (lipopolysaccharide) was injected along with the cell wall fraction. resistance was measured both by enumerating the bacteria ...	1974	16558105
effects of dextran sulfate 500 on cell-mediated resistance to infection with listeria monocytogenes in mice.	injection of dextran sulfate 500 caused loss of antibacterial resistance. mice became more susceptible to an infection with listeria monocytogenes and were unable to develop antilisterial immunity after both active and passive immunization with passively administered spleen cells from listeria-immune donors. indirect evidence suggests that the phagocytic component of cell-mediated resistance to bacterial infection is the site of attack of dextran sulfate.	1974	16558097
extracellular antigens from listeria monocytogenes i. purification and resolution of hemolytic and lipolytic antigens from culture filtrates of listeria monocytogenes.	two antigens were purified from culture filtrates of listeria monocytogenes 7973 by the following procedure: (i) acid precipitation with 4 n hcl at ph 3.7, (ii) sephadex g-75 column fractionation, (iii) diethylaminoethyl-sephadex a50 batchwise adsorption, and (iv) rechromatography on sephadex g-75. this procedure resulted in the resolution of two distinct antigens. one antigen, designated a hemolytic antigen because of its ability to lyse erythrocytes from a variety of species, had a specific ac ...	1971	16558022
drug potentiation of macrophage function.	the mechanism by which macrophages kill facultative intracellular parasites is not known. a test system is described utilizing human macrophages derived from blood monocytes and the opportunistic pathogen listeria monocytogenes. in this system, bacterial killing was impaired under hypoxic conditions. under aerobic conditions, addition of clofazimine (b663), a phenazine derivative effective in the treatment of human leprosy, potentiated the killing of listeria by macrophages. potentiation occurre ...	1970	16557883