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host ranges of listeria-specific bacteriophages from the turkey processing plant environment in the united states.even though at least 400 listeria phages have been isolated from various sources, limited information is available on phages from the food processing plant environment. phages in the processing plant environment may play critical roles in determining the listeria population that becomes established in the plant. in this study, we pursued the isolation of listeria-specific phages from environmental samples from four turkey processing plants in the united states. these environmental samples were a ...200818791016
inla premature stop codons are common among listeria monocytogenes isolates from foods and yield virulence-attenuated strains that confer protection against fully virulent strains.previous studies showed that a considerable proportion of listeria monocytogenes isolates obtained from foods carry a premature stop codon (pmsc) mutation in inla that leads to production of a truncated and secreted inla. to further elucidate the role these mutations play in virulence of l. monocytogenes, we created isogenic mutants, including (i) natural isolates where an inla pmsc was reverted to a wild-type inla allele (without a pmsc) and (ii) natural isolates where a pmsc mutation was intro ...200818791029
immunological and pathological changes in the placenta during infection with listeria monocytogenes in pregnant guinea pigs.exposure to listeria monocytogenes during pregnancy can result in spontaneous abortion and stillbirths; however, the mechanisms are unknown. our objective was to determine the effects of infection on specific inflammatory and anti-inflammatory cytokine mrna expression and apoptosis in the placenta after infection with l. monocytogenes. pregnant guinea pigs were treated on gestation day (gd) 35 with 10(8) colony forming units l. monocytogenes and sacrificed on gd 37, 41, 44, or 55. at gd 41, ifn- ...200818793713
evaluating the growth of listeria monocytogenes in refrigerated ready-to-eat frankfurters: influence of strain, temperature, packaging, lactate and diacetate, and background microflora.this research was conducted to study the growth of listeria monocytogenes inoculated on frankfurters stored at different conditions as a basis for a safety-based consume by shelf life date label. three l. monocytogenes strains were separately inoculated at 10 to 20 cfu/cm2 onto frankfurters that were previously formulated with or without high pressure and with or without added 2% potassium lactate (pl) and 0.2% sodium diacetate (sd). inoculated frankfurters were air or vacuum packaged; stored at ...200818810864
competitiveness and antibacterial potential of bacteriocin-producing starter cultures in different types of fermented sausages.application of bacteriocin-producing starter cultures of lactic acid bacteria in fermented sausage production contributes to food safety. this is sometimes hampered by limited efficacy in situ and by uncertainty about strain dependency and universal applicability for different sausage types. in the present study, a promising antilisterial-bacteriocin producer, lactobacillus sakei ctc 494, was applied as a coculture in addition to commercial fermentative starters in different types of dry-ferment ...200818810865
dynamic modeling of listeria monocytogenes growth in pasteurized vanilla cream after postprocessing contamination.a product-specific model was developed and validated under dynamic temperature conditions for predicting the growth of listeria monocytogenes in pasteurized vanilla cream, a traditional milk-based product. model performance was also compared with growth predictor and sym'previus predictive microbiology software packages. commercially prepared vanilla cream samples were artificially inoculated with a five-strain cocktail of l. monocytogenes, with an initial concentration of 102 cfu g(-1), and sto ...200818810866
modeling survival of listeria monocytogenes in the traditional greek soft cheese katiki.in the present work, survival of listeria monocytogenes in the traditional greek soft, spreadable cheese katiki was studied throughout the shelf life of the product. samples of finished cheese were inoculated with a cocktail of five l. monocytogenes strains (ca. 6 log cfu g(-1)) and stored at 5, 10, 15, and 20 degrees c. acid-stress adaptation or cross-protection to the same stress was also investigated by inoculation of acid-adapted cells in the product. the results showed that pathogen surviva ...200818810867
efficacy of plant essential oils against foodborne pathogens and spoilage bacteria associated with ready-to-eat vegetables: antimicrobial and sensory screening.the objectives of this study were to evaluate the antimicrobial activity of plant essential oils (eos) against foodborne pathogens and key spoilage bacteria pertinent to ready-to-eat vegetables and to screen the selected eos for sensory acceptability. the eos basil, caraway, fennel, lemon balm, marjoram, nutmeg, oregano, parsley, rosemary, sage, and thyme were evaluated. the bacteria evaluated were listeria spp., staphylococcus aureus, lactobacillus spp., bacillus cereus, salmonella, enterobacte ...200818810868
enhanced inactivation of foodborne pathogenic and spoilage bacteria by fd&c red no. 3 and other xanthene derivatives during ultrahigh pressure processing.variability among microorganisms in barotolerance has been demonstrated at genus, species, and strain levels. identification of conditions and additives that enhance the efficacy of ultrahigh pressure (uhp) against important foodborne microorganisms is crucial for maximizing product safety and stability. preliminary work indicated that fd&c red no. 3 (red 3), a xanthene derivative, was bactericidal and acted synergistically with uhp against lactobacillus spp. the objective of this study was to d ...200818810870
modeling the physiological state of the inoculum and co2 atmosphere on the lag phase and growth rate of listeria monocytogenes.in previous studies, the growth of l. monocytogenes has been modeled under different co2 headspace concentrations; however, the inoculum cells were always in the stationary phase. in this study, the growth of l. monocytogenes under different co2 concentrations as affected by the physiological state of the cells was investigated. exponential-growth-phase, stationary-phase, dried, and starved cells were prepared and inoculated at 5 degrees c into brain heart infusion broths that had been preequili ...200818810878
antibacterial activity of xanthorrhizol isolated from curcuma xanthorrhiza roxb. against foodborne pathogens.xanthorrhizol, isolated from the ethanol extract of curcuma xanthorrhiza roxb., is a sesquiterpene compound with a molecular weight of 218. the aim of this study was to investigate the antibacterial activity of xanthorrhizol against foodborne pathogens. the antibacterial activity of xanthorrhizol was measured in terms of the mic and the mbc. mics and mbcs of xanthorrhizol against bacillus cereus, clostridium perfringens, listeria monocytogenes, staphylococcus aureus, salmonella typhimurium, and ...200818810881
microbial and sensory characteristics of camel meat during refrigerated storage as affected by gamma irradiation.the present study was undertaken to assess the microbiological profile of fresh camel meat and the possibility of improving microbial quality and extending the refrigerated storage life of meat by using low-dose gamma irradiation. camel meat samples were subjected to 0 (control), 1.5 and 3 kgy doses and stored at 3 +/- 1 degrees c. the microbial and sensory attributes were evaluated. exposure to 1.5 kgy dose significantly reduced the initial counts of aerobic plate counts (apcs), psychrophilic b ...200818814652
gilt is a critical host factor for listeria monocytogenes infection.listeria monocytogenes is a gram-positive, intracellular, food-borne pathogen that can cause severe illness in humans and animals. on infection, it is actively phagocytosed by macrophages; it then escapes from the phagosome, replicates in the cytosol, and subsequently spreads from cell to cell by a non-lytic mechanism driven by actin polymerization. penetration of the phagosomal membrane is initiated by the secreted haemolysin listeriolysin o (llo), which is essential for vacuolar escape in vitr ...200818815593
protein expression by listeria monocytogenes grown on a rte-meat matrix.little is known about whether the growth of l. monocytogenes on a ready-to-eat (rte) meat matrix has an impact on the bacterium's pathogenic capabilities. in this report, we examined protein expression by l. monocytogenes grown on rte sliced turkey meat, using l. monocytogenes grown on brain-heart-infusion agar as a control. total protein fractions of l. monocytogenes from both growth conditions were extracted and compared by two-dimensional gel electrophoresis. seventy-seven proteins expressed ...200818817996
mechanism of synergistic inhibition of listeria monocytogenes growth by lactic acid, monolaurin, and nisin.the combined lactic acid, monolaurin, and nisin effects on time-to-detection (optical density at 600 nm) extension were greater (p < 0.05) than any single or paired combination effect, which demonstrates a synergistic interaction among the antimicrobials. monolaurin exposure caused c12:0 cell membrane incorporation. lactic acid caused increased monolaurin c12:0 membrane incorporation, while nisin had no influence. we postulate that lactic acid-enhanced monolaurin c12:0 incorporation into the cel ...200818820062
high sensitivity of intestinal cd8+ t cells to nucleotides indicates p2x7 as a regulator for intestinal t cell responses.the purinoreceptor p2x7 is expressed on subsets of t cells and mediates responses of these cells to extracellular nucleotides such as atp or nad(+). we identified p2x7 as a molecule highly up-regulated on conventional cd8alphabeta(+) and unconventional cd8alphaalpha(+) t cells of the intestinal epithelium of mice. in contrast, cd8(+) t cells derived from spleen, mesenteric lymph nodes, and liver expressed only marginal levels of p2x7. however, p2x7 was highly up-regulated on cd8(+) t cells from ...200818768840
cross-tolerization between nod1 and nod2 signaling results in reduced refractoriness to bacterial infection in nod2-deficient macrophages.nod2 is an intracellular innate immune receptor that plays a role in host defense and susceptibility to inflammatory disease. we show in this study that macrophages rendered refractory to tlr4 and nod2 signaling by exposure to lps and muramyl dipeptide (mdp) exhibit impaired tnf-alpha and il-6 production in response to pathogenic listeria monocytogenes and yersinia pseudotuberculosis as well as commensal bacteria including escherichia coli and bacteroides fragilis. surprisingly, nod2 deficiency ...200818768892
induction of autophagy via innate bacterial recognition.macroautophagy (referred to hereafter as autophagy) functions not only in self-digestion, but also in the killing and degradation of infectious pathogens in in vitro-cultured cells. based on genetic manipulations of both the host, drosophila and pathogen, listeria monocytogenes, we recently reported that l. monocytogenes-induced autophagy is dependent on the recognition of the pathogen by the drosophila pattern recognition protein, pgrp-le. autophagy and pgrp-le are crucial for inhibition of the ...200818769162
xiap regulates cytosol-specific innate immunity to listeria infection.the inhibitor of apoptosis protein (iap) family has been implicated in immune regulation, but the mechanisms by which iap proteins contribute to immunity are incompletely understood. we show here that x-linked iap (xiap) is required for innate immune control of listeria monocytogenes infection. mice deficient in xiap had a higher bacterial burden 48 h after infection than wild-type littermates, and exhibited substantially decreased survival. xiap enhanced nf-kappab activation upon l. monocytogen ...200818769721
yersinia enterocolitica yop mutants as oral live carrier vaccines.attenuated enteropathogenic yersiniae that translocate heterologous antigens into the cytosol of antigen presenting cells via their type three secretion system (ttss) are considered promising candidates for the development of live oral vaccine carrier strains that induce cd8 t cell responses. wild type yersinia enterocolitica of serotype o:8 however efficiently suppresses the immune response of the host by translocating effector proteins called yersinia outer proteins (yops) into the cytosol of ...200818822332
frontiers in immunology research network--2008 international conference. 200818828067
effect of gamma radiation on heat shock protein expression of four foodborne pathogens.the effects of gamma radiation on three heat shock proteins (hsps) (groel, dnak and groes) synthesis in two gram-negative (escherichia coli and salmonella serotype typhimurium) and two gram-positive (staphylococcus aureus and listeria monocytogenes) bacteria were investigated.200818828787
cancer immunotherapy targeting the high molecular weight melanoma-associated antigen protein results in a broad antitumor response and reduction of pericytes in the tumor vasculature.the high molecular weight melanoma-associated antigen (hmw-maa), also known as melanoma chondroitin sulfate proteoglycan, has been used as a target for the immunotherapy of melanoma. this antigen is expressed on the cell surface and has a restricted distribution in normal tissues. besides its expression in a broad range of transformed cells, this antigen is also found in pericytes, which are important for tumor angiogenesis. we generated a recombinant listeria monocytogenes (lm-llo-hmw-maa-c) th ...200818829565
endoplasmic reticulum stress regulator xbp-1 contributes to effector cd8+ t cell differentiation during acute infection.the transcription factor x-box-binding protein-1 (xbp-1) plays an essential role in activating the unfolded protein response in the endoplasmic reticulum (er). transcribed xbp-1 mrna is converted to its active form by unconventional cytoplasmic splicing mediated by inositol-requiring enzyme-1 (ire-1) upon er stress. we report activation of the ire-1/xbp-1 pathway in effector cd8(+) t cells during the response to acute infection. transcription of unspliced xbp-1 mrna is up-regulated by il-2 signa ...200818832700
[bacteriological evaluation of goat milk and cheese distributed in the metropolitan area of san josé, costa rica].in the last years, there has been an increase in the production, industrialization and consumption of goat's milk and derivate products, including cheese, worldwide. nevertheless, in costa rica there is no study of these products, reason why the objective of this work was to determine the microbiological characteristics of goat's milk and fresh cheese distributed in the metropolitan area of san josé, costa rica, in order to evaluate its impact in the economical field and as a potential risk for ...200818833996
a novel dna microarray for rapid diagnosis of enteropathogenic bacteria in stool specimens of patients with diarrhea.a microarray technique for the detection and identification of enteropathogenic bacteria at the species and subspecies levels was developed in this study, and the target bacteria included pathogenic escherichia coli, vibrio cholerae, vibrio parahaemolyticus, salmonella enterica, campylobacter jejuni, shigellae, yersinia enterocolitica, and listeria monocytogenes. the virulence gene of each pathogen was chosen as the amplification target, labeled with a fluorescence dye by multiplex polymerase ch ...200818834908
pulsed-field gel electrophoresis (pfge) analysis of listeria monocytogenes isolates from different sources and geographical origins and representative of the twelve serovars.multiplex-pcr (mpcr) serogrouping and pulsed-field gel electrophoresis (pfge) subtyping analysis are currently used by several public and private laboratories for the characterization of listeria monocytogenes. in this study a set of 80 l. monocytogenes isolates belonging to the twelve serovars was used to investigate (i) the typeability of the rare serovars, (ii) the ability of pfge analysis with apai and asci to differentiate serovars within mpcr serogroups and (iii) the association of molecul ...200818835121
a putative abc transporter is involved in negative regulation of biofilm formation by listeria monocytogenes.listeria monocytogenes may persist for long periods in food processing environments. in some instances, this may be due to aggregation or biofilm formation. to investigate the mechanism controlling biofilm formation in the food-borne pathogen l. monocytogenes, we characterized lm-49, a mutant with enhanced ability of biofilm formation generated via transposon tn917 mutagenesis of l. monocytogenes 4b g. in this mutant, a tn917 insertion has disrupted the coding region of the gene encoding a putat ...200818836003
comparative analysis of extracellular and intracellular proteomes of listeria monocytogenes strains reveals a correlation between protein expression and serovar.listeria monocytogenes, the etiologic agent of listeriosis, remains a serious public health concern, with its frequent occurrence in food environments coupled with a high mortality rate. among the 13 serovars, human listeriosis is mostly associated with the serovar 4b, 1/2b, and 1/2a strains. to investigate the diversity of l. monocytogenes, the intracellular and extracellular proteins of 12 strains were analyzed by two-dimensional gel electrophoresis. these strains had different origins, belong ...200818836007
development and implementation of a multiplex single-nucleotide polymorphism genotyping assay for detection of virulence-attenuating mutations in the listeria monocytogenes virulence-associated gene inla.the virulence factor internalin a (inla) facilitates the uptake of listeria monocytogenes by epithelial cells that express the human isoform of e-cadherin. previous studies identified naturally occurring premature stop codon (pmsc) mutations in inla and demonstrated that these mutations are responsible for virulence attenuation. we assembled >1,700 l. monocytogenes isolates from diverse sources representing 90 ecori ribotypes. a subset of this isolate collection was selected based on ribotype fr ...200818836010
immunomagnetic separation and pcr detection of listeria monocytogenes in turkey meat and antibiotic resistance of the isolates.1. conventional cultivation and immunomagnetic separation (ims) cultivation methods were compared for the isolation specificity and sensitivity of l. monocytogenes from turkey meat samples. pcr was used to confirm the isolates. disc diffusion was performed to determine the antibiotic susceptibility profiles. a total of 180 turkey meat samples collected from markets in turkey were tested. 2. l. monocytogenes was detected in 23 samples (12.7%) by ims and conventional cultivation. it was isolated f ...200818836902
bacteriophage therapy and the mutant selection window.we use kinetic models to investigate how to design antimicrobial phage therapies to minimize emergence of resistant bacteria. we do this by modifying the "mutant selection window" hypothesis in a way that accounts for the ongoing self-replication of the phage. we show that components of combination phage therapies need to be appropriately matched if treatment is to avoid the emergence of resistant bacteria. matching of components is more easily achieved when phage dosages are high enough that on ...200818838590
birth-and-death evolution of the internalin multigene family in listeria.the birth-and-death model of multigene family evolution describes patterns of gene origination, diversification and loss within multigene families. since it was first developed in the 1990s, the model has been found to characterize a large number of eukaryotic multigene families. in this paper, we report for the first time a bacterial multigene family that undergoes birth-and-death evolution. by analyzing the evolutionary relationships among internalins, a relatively large and diverse family of ...200818840511
lineage specific recombination rates and microevolution in listeria monocytogenes.the bacterium listeria monocytogenes is a saprotroph as well as an opportunistic human foodborne pathogen, which has previously been shown to consist of at least two widespread lineages (termed lineages i and ii) and an uncommon lineage (lineage iii). while some l. monocytogenes strains show evidence for considerable diversification by homologous recombination, our understanding of the contribution of recombination to l. monocytogenes evolution is still limited. we therefore used structure and c ...200818842152
enhancing bile tolerance improves survival and persistence of bifidobacterium and lactococcus in the murine gastrointestinal tract.the majority of commensal gastrointestinal bacteria used as probiotics are highly adapted to the specialised environment of the large bowel. however, unlike pathogenic bacteria; they are often inadequately equipped to endure the physicochemical stresses of gastrointestinal (gi) delivery in the host. herein we outline a patho-biotechnology strategy to improve gastric delivery and host adaptation of a probiotic strain bifidobacterium breve ucc2003 and the generally regarded as safe (gras) organism ...200818844989
outbreak of listeria monocytogenes infections associated with pasteurized milk from a local dairy--massachusetts, 2007.on november 27, 2007, a local health officer in central massachusetts contacted the massachusetts department of public health (mdph) to report listeriosis in a man aged 87 years. pulsed-field gel electrophoresis (pfge) performed on the patient's listeria monocytogenes isolate produced a pattern indistinguishable from that of isolates from three other cases identified in residents of central massachusetts in june, october, and early november 2007. mdph, in collaboration with local public health o ...200818846031
characterization of human invasive isolates of listeria monocytogenes in sweden 1986-2007.since 1986, 68% of the listeria monocytogenes isolates from human cases of invasive listeriosis in sweden are available for retrospective studies. the aim of the present study was to characterize 601 human invasive isolates of l. monocytogenes in sweden from 1986 to 2007 by using serotyping and pulsed-field gel electrophoresis. since 1996, serovar 4b was permanently reduced to the second or third most common serovar in human cases in sweden. during the latter period, 2000-2007, only 13% belonged ...200818847381
precut prepackaged lettuce: a risk for listeriosis?the most recent outbreaks of listeriosis have been traced back to contaminated ready-to-eat (rte) poultry and meat products. however, listeria monocytogenes can be isolated from every food group, including fresh vegetables. this review is focused on one of the most popular rte vegetable products, precut prepackaged lettuce. the available literature concerning listeria contamination of vegetables is reviewed, and possible reasons why no recent outbreaks or sporadic cases of listeriosis due to con ...200818847382
the tsc-mtor signaling pathway regulates the innate inflammatory response.the innate inflammatory immune response must be tightly controlled to avoid damage to the host. here, we showed that the tuberous sclerosis complex-mammalian target of rapamycin (tsc-mtor) pathway regulated inflammatory responses after bacterial stimulation in monocytes, macrophages, and primary dendritic cells. inhibition of mtor by rapamycin promoted production of proinflammatory cytokines via the transcription factor nf-kappab but blocked the release of interleukin-10 via the transcription fa ...200818848473
dynamic regimes and bifurcations in a model of actin-based motility.propulsion by actin polymerization is widely used in cell motility. here, we investigate a model of the brush range of an actin gel close to a propelled object, describing the force generation and the dynamics of the propagation velocity. we find transitions between stable steady states and relaxation oscillations when the attachment rate of actin filaments to the obstacle is varied. the oscillations set in at small values of the attachment rate via a homoclinic bifurcation. a second transition ...200818851073
[encephalomeningitis caused by listeria monocytogenes in patient infected by tbe virus--case report].the epidemiology of listeriosis is constantly changing towards higher incidence. the most endangered group of patients are people with immunodeficiency caused by coexisting diseases. in these cases listeriosis may take a very severe course. in this paper we present a case of a 76 year old female who suffered from encephalomeningitis caused by listeria monocytogenes and additionally was infected by tick borne encephalitis virus and borrelia burgdorferi.200822320051
antilisterial activity of plantaricin ug1 during manufacture of zabady and kareesh cheese: two arabian dairy products.here, plantaricin ug1 was shown to inhibit listeria monocytogenes lmg10470 (l. monocytogenes) cells. the inhibition was not caused by lactic acid produced by the bacteriocin producing strain lactobacillus plantarum ug1 (lact. plantarum). partially purified plantaricin ug1 had a higher antilisterial activity than lact. plantarum cells in both zabady and kareesh cheese samples during their maturation. compared to the antilisterial activity in kareesh cheese, plantaricin ug1 showed a faster effect ...200823675104
synergistic effect of nisin and garlic shoot juice against listeria monocytogenes in milk.the aim of this research was to determine the synergistic effect of nisin and garlic shoot juice (gsj) against listeria monocytogenes atcc 19118 found in whole (3.5%), low (1%) and skim (no fat content) milk. garlic shoot juice (gsj) at concentrations of 2.5%, 5% and 10% revealed strong and similar patterns of antilisterial effect against l. monocytogenes atcc 19118 in all categories of milk. nisin only at concentrations of 62.5, 125, 250 and 500iu/ml displayed a strong antilisterial effect as c ...200826049229
quantitative evaluation of listeria monocytogenes in fresh and processed surubim fish (pseudoplatystoma sp).l. monocytogenes is a foodborne psychrotrophic bacterial pathogen of special importance for minimally processed foods. in this work, it was enumerated in samples of surubim fish by mpn technique. the population of l. monocytogenes was estimated as < 0.012 mpn/cm(2) in fresh and < 0.03 mpn/g in minimally processed fish.200824031260
behaviour of l. monocytogenes in sliced, vacuum-packed mortadella.this study evaluated the growth of naturally occurring l. monocytogenes in sliced, vacuum-packed mortadella samples during storage at 5°c until the expiration date. tukey's test indicated that counts of l. monocytogenes on 0, 10, 20, 30 and 40 days of storage were significantly different (p<0.05), indicating growth during shelf life. in three trials, the mean increase was 1.72 log cycles. vacuum packing and storage under refrigeration were not effective in controlling the growth of l. monocytoge ...200824031257
epidemiological survey of listeria monocytogenes in a gravlax salmon processing line.listeria monocytogenes is a cause of concern to food industries, mainly for those producing ready-to-eat (rte) products. this microorganism can survive processing steps such as curing and cold smoking and is capable of growing under refrigeration temperatures. its presence in rte fish products with extended shelf life may be a risk to the susceptible population. one example of such a product is gravlax salmon; a refrigerated fish product not exposed to listericidal processes and was the subject ...200824031233
molecular analysis of the iap gene of listeria monocytogenes isolated from cheeses in rio grande do sul, brazil.the polymorphic region sequences in the iap gene were analyzed in 25 strains of listeria monocytogenes isolated from cheeses in the state of rio grande do sul, and compared with reference strains. this investigation distinguished two clusters of l. monocytogenes: i (20 strains) and ii (5 strains).200824031198
interference of raw milk autochthonous microbiota on the performance of conventional methodologies for listeria monocytogenes and salmonella spp. detection.pathogen detection in foods by reliable methodologies is very important to guarantee microbiological safety. however, peculiar characteristics of certain foods, such as autochthonous microbiota, can directly influence pathogen development and detection. with the objective of verifying the performance of the official analytical methodologies for the isolation of listeria monocytogenes and salmonella in milk, different concentrations of these pathogens were inoculated in raw milk treatments with d ...200917720465
colony-stimulating factor-1-dependent macrophage functions regulate the maternal decidua immune responses against listeria monocytogenes infections during early gestation in mice.the association between extreme-prematurity births and intrauterine infection emphasizes the importance of understanding the host immune responses against uterine-invading microbes during early pregnancy to the prevention of preterm births. listeria monocytogenes, a clinically relevant intracellular bacterium, has a predilection for replication at the maternofetal interface during pregnancy. here, using mice carrying the recessive null osteopetrotic mutation in the colony-stimulating factor-1 (c ...200918852237
listeria monocytogenes: maternal-foetal infections in denmark 1994-2005.maternal-foetal infection by listeria monocytogenes is a rare complication in pregnancy. in the period 1994-2005, 37 culture-confirmed cases of maternal-foetal listeria monocytogenes infections were reported in denmark. we examined 36 patients' files in order to evaluate risk factors, clinical and laboratory findings, response to therapy, and outcome for maternal-foetal listeriosis. patient data and bacteriological findings were divided into 2 groups for comparison: 1 group with children born al ...200918855227
[listeria and listeriosis: from farm to fork].listeria monocytogenes is a bacterium widely spread in the environment. its persistence in industrial environment leads to food product contamination from the raw materials and constitutes a recurrent problem in food processing industry despite the use of cold chain procedures. l. monocytogenes is a foodborne pathogen causing severe and life-threatening infections that evolve mainly under sporadic mode, even if epidemics sometimes occur. listeriosis causes mainly septicemia, central nervous syst ...200918829183
chronic ethanol induces inhibition of antigen-specific cd8+ but not cd4+ immunodominant t cell responses following listeria monocytogenes inoculation.chronic ethanol consumption results in immunodeficiency. previous work with chronic ethanol-fed mice has shown reduced splenic weight and cellularity, including reduced numbers of cd8+ t cells. however, antigen-specific cd8+ and cd4+ t cell responses in chronic ethanol-fed mice have been studied relatively little. we have used an attenuated listeria monocytogenes strain dpl 1942 (lm deltaacta) to inoculate mice and subsequently used cd4+ and cd8+ immunodominant peptides of lm to measure the cd4+ ...200918820175
a survey of laboratory-confirmed isolates of invasive listeriosis in israel, 1997-2007.during the 11-year period from 1997 to 2007, 321 isolates of listeria monocytogenes from sporadic cases of invasive listeriosis were reported to the national reference laboratory in israel. of these isolates, 113 (35%) were identified from perinatal cases, and 208 (65%) from non-perinatal cases. the prevalent serovars were 4b, 1/2b, 1/2a and 4c. serovar 4b was identified in 80.5% of the perinatal isolates (p=0.0162), while the number of 1/2b and 1/2a strains increased in the > or = 60 years old ...200918796168
immunosensitization with a bcl-2 small molecule inhibitor.several tumor immunotherapy approaches result in a low percentage of durable responses in selected cancers. we hypothesized that the insensitivity of cancer cells to immunotherapy may be related to an anti-apoptotic cancer cell milieu, which could be pharmacologically reverted through the inhibition of antiapoptotic bcl-2 family proteins in cancer cells. abt-737, a small molecule inhibitor of the antiapoptotic proteins bcl-2, bcl-w and bcl-x(l), was tested for the ability to increase antitumor i ...200918807035
risk factors associated with the presence of viable listeria monocytogenes in bulk tank milk from us dairies.the objective of the study was to screen a large number of herd management practices and herd characteristics from us dairies to identify herd-level risk factors associated with the presence of listeria monocytogenes in bulk tank milk (btm). a total of 71 variables was univariately evaluated for their association with the presence of l. monocytogenes in btm. results from the univariate analysis indicated that using automatic take offs and having an open herd management increased the risk of btm ...200918705657
adenovirus-mediated gene transfer of pathogen-associated molecular patterns for cancer immunotherapy.the delivery of stimulatory signals to dendritic cells (dcs) in the tumor microenvironment could be an effective means to break tumor-induced tolerance. the work presented here evaluates the immunostimulatory properties of pathogen-associated molecular patterns (pamps), microbial molecules which bind toll-like receptors and deliver activating signals to immune cells, when expressed in tumor cells using adenoviral (ad) vectors. in vitro, transduction of a549 tumor cells with ad vectors expressing ...200918949016
listerial rhombencephalitis in an immunocompetent young adult.listeria monocytogenes is a common cause of central nervous system infections, especially in immunosuppressed patients, infants and elderly people. listerial rhombencephalitis is a rare and severe infection of the brainstem that is reported to have high mortality and frequent serious sequelae for survivors. we report the case of a 19-year-old healthy male who presented with listerial brainstem infection due to listeria monocytogenes.200918926754
growth, survival, proliferation and pathogenesis of listeria monocytogenes under low oxygen or anaerobic conditions: a review.listeria monocytogenes is a gram positive facultative anaerobe that causes listeriosis, a disease that mainly affects the immune-compromised, the elderly, infants and pregnant women. in the susceptible immune challenged population, listeriosis is very severe and has a fatality rate of up to 30%. control of l. monocytogenes is difficult due to its: 1) widespread presence in the environment, 2) intrinsic physiological resistance, 3) ability to adapt to external stresses and 4) ability to grow at a ...200918926916
the bradykinin b2 receptor in the early immune response against listeria infection.the endogenous danger signal bradykinin was recently found implicated in the development of immunity against parasites via dendritic cells. we here report an essential role of the b(2) (b(2)r) bradykinin receptor in the early immune response against listeria infection. mice deficient in b(2)r (b(2)r(-/-) mice) were shown to suffer from increased hepatic bacterial burden and concomitant dramatic weight loss during infection with listeria monocytogenes. levels of cytokines known to play a pivotal ...200918810490
short-term inhalation exposure to mild steel welding fume had no effect on lung inflammation and injury but did alter defense responses to bacteria in rats.many workers worldwide are continually exposed to complex aerosols generated from welding processes. the objective was to assess the effect of inhalation exposure to mild steel (ms) welding fume on lung injury, inflammation, and defense responses. male sprague-dawley rats were exposed to ms fume at a concentration of 40 mg/m(3) x 3 h/day x 3 or 10 days using a robotic welding fume generator. controls were exposed to filtered air. to assess lung defense responses, a group of animals were intratra ...200918925477
streptococcus mutans smu.623c codes for a functional, metal-dependent polysaccharide deacetylase that modulates interactions with salivary agglutinin.the genome sequence of the oral pathogen streptococcus mutans predicts the presence of two putative polysaccharide deacetylases. the first, designated pgda in this paper, shows homology to the catalytic domains of peptidoglycan deacetylases from streptococcus pneumoniae and listeria monocytogenes, which are both thought to be involved in the bacterial defense mechanism against human mucosal lysozyme and are part of the cazy family 4 carbohydrate esterases. s. mutans cells in which the pgda gene ...200918978064
first molluscan tnf-alpha homologue of the tnf superfamily in disk abalone: molecular characterization and expression analysis.tumor necrosis factor alpha (tnf-alpha) is considered as a multifunctional immune modulator that plays an important role in the innate and adaptive immune systems in vertebrates. here, we described the characterization and expression analysis of the first tnf-alpha homologue in mollusk abalone, named as abtnf-alpha. it has 930-bp full length with a 717-bp open reading frame (orf), encoding 239 amino acids. the abtnf-alpha amino acid sequence shows the characteristic tnf family signature, n-termi ...200918984056
listeria monocytogenes in gorgonzola: subtypes, diversity and persistence over time.l. monocytogenes represents a primary concern in the production of gorgonzola, a protected designation of origin (pdo) italian blue-veined cheese produced only in the piedmont and lombardy regions. l. monocytogenes isolates (n=95) obtained from gorgonzola rinds, paste, and production/ripening environments were serotyped and then genotyped using pulsed field gel electrophoresis (pfge). the goal of this study was to investigate the variability of l. monocytogenes pfge-types across different pdo go ...200918990461
met receptor tyrosine kinase degradation is altered in response to the leucine-rich repeat of the listeria invasion protein internalin b.entry of the bacterial pathogen listeria monocytogenes into host epithelial cells is critical for infection and virulence. one major pathway for listeria entry involves binding of the bacterial protein internalin b to the host receptor tyrosine kinase met (hepatocyte growth factor receptor). activation of met and downstream signaling cascades is critical for listeria entry. internalin b is composed of several structural domains including an n-terminal leucine-rich repeat that is sufficient for b ...200918990695
effect of treating lettuce surfaces with acidulants on the behaviour of listeria monocytogenes during storage at 5 and 20 degrees c and subsequent exposure to simulated gastric fluid.the effect of acid decontamination on the growth/survival of listeria monocytogenes on fresh lettuce (lactusa sativa) during storage and subsequent exposure to a simulated gastric fluid was studied. fresh lettuce, inoculated with l. monocytogenes (3 log cfu/cm(2)), was immersed (20 degrees c, 90 s) in water (w), lactic acid (la), acetic acid (aa), propionic acid (pa) and citric acid (ca) at concentrations 0.5 and 1.0%, and then stored aerobically at 5 and 20 degrees c for 20 and 10 days, respect ...200919022513
protochlorophyllide: a new photosensitizer for the photodynamic inactivation of gram-positive and gram-negative bacteria.the growing resistance against antibiotics demands the search for alternative treatment strategies. photodynamic therapy is a promising candidate. the natural intermediate of chlorophyll biosynthesis, protochlorophyllide, was produced, purified and tested as a novel photosensitizer for the inactivation of five model organisms including staphylococcus aureus, listeria monocytogenes and yersinia pseudotuberculosis, all responsible for serious clinical infections. when microorganisms were exposed t ...200919025572
characterization of polyvalent and safe bacillus thuringiensis strains with potential use for biocontrol.sixteen bacillus thuringiensis (bt) strains were screened for their anti-insect, antibacterial and antifungal determinants by phenotypic tests and pcr targeting major insecticidal proteins and complements, chitinases, lactonases, beta-1,3-glucanases and zwittermicina. six strains had genes of at least two major insecticidal toxins and of insecticidal complements. with regard to fungal biocontrol, all the strains inhibited fusarium oxysporum and aspergillus flavus growth and four strains had all ...200919025870
construction and characterization of an attenuated listeria monocytogenes strain for clinical use in cancer immunotherapy.listeria monocytogenes has been exploited previously as a vaccine vector for the delivery of heterologous proteins such as tumor-specific antigens for active cancer immunotherapy. however, for effective use of live vector in clinics, safety is a major concern. in the present study, we describe an irreversibly attenuated and highly immunogenic l. monocytogenes platform, the l. monocytogenes dal-, dat-, and acta-deleted strain that expresses the human prostate-specific antigen (psa) using an antib ...200919020110
divercin v41 from gene characterization to food applications: 1998-2008, a decade of solved and unsolved questions.the emergence of an increasing number of antibiotic resistant human clinical bacteria has been a great cause of concern for the last decades. as an example, staphylococcus aureus isolates in the hospital environment are becoming more and more resistant to antibiotics including vancomycin which is considered as a last line of defence in treatment of staphylococcus aureus-resistant methicillin. on the other hand, food safety is threatened by development of pathogenic bacteria including listeria mo ...200919018960
signalling mechanisms for toll-like receptor-activated neutrophil exocytosis: key roles for interleukin-1-receptor-associated kinase-4 and phosphatidylinositol 3-kinase but not toll/il-1 receptor (tir) domain-containing adaptor inducing ifn-beta (trif).lipopolysaccharide (lps) stimulates exocytosis in neutrophils. the signalling molecules involved in the regulation of this mechanism are currently unknown. using neutrophils from interleukin-1-receptor-associated kinase (irak)-4- and toll/il-1 receptor (tir) domain-containing adaptor inducing ifn-beta (trif)-deficient mice, we dissected the signalling pathways that control exocytosis. we analysed exocytosis of peroxidase-negative and azurophilic granules by following the mobilization of the beta ...200919019092
a small-molecule screen identifies the antipsychotic drug pimozide as an inhibitor of listeria monocytogenes infection.we developed a screening procedure to identify small-molecule compounds that altered infection by listeria monocytogenes to gain insights into bacterial/host cellular processes required for intracellular pathogenesis. a small-molecule library of 480 compounds with known biological functions was screened, and 21 compounds that altered the l. monocytogenes infection of murine bone marrow-derived macrophages (bmm) were identified. the identified compounds affected various cellular functions, such a ...200919015342
ccpc-dependent regulation of citrate synthase gene expression in listeria monocytogenes.citrate synthase, the first and rate-limiting enzyme of the tricarboxylic acid branch of the krebs cycle, was shown to be required for de novo synthesis of glutamate and glutamine in listeria monocytogenes. the citrate synthase (citz) gene was found to be part of a complex operon with the upstream genes lmo1569 and lmo1568. the downstream isocitrate dehydrogenase (citc) gene appears to be part of the same operon as well. two promoters were shown to drive citz expression, a distal promoter locate ...200919011028
modeling the growth/no-growth boundaries of postprocessing listeria monocytogenes contamination on frankfurters and bologna treated with lactic acid.this study developed models to predict lactic acid concentration, dipping time, and storage temperature combinations determining growth/no-growth interfaces of listeria monocytogenes at desired probabilities on bologna and frankfurters. l. monocytogenes was inoculated on bologna and frankfurters, and 75 combinations of lactic acid concentrations, dipping times, and storage temperatures were tested. samples were stored in vacuum packages for up to 60 days, and bacterial populations were enumerate ...200919011067
virulent bacteriophage for efficient biocontrol of listeria monocytogenes in ready-to-eat foods.food-borne listeria monocytogenes is a serious threat to human health, and new strategies to combat this opportunistic pathogen in foods are needed. bacteriophages are natural enemies of bacteria and are suitable candidates for the environmentally friendly biocontrol of these pathogens. in a comprehensive set of experiments, we have evaluated the virulent, broad-host-range phages a511 and p100 for control of l. monocytogenes strains scott a (serovar 4b) and wslc 1001 (serovar 1/2a) in different ...200919011076
characterization of antimicrobial resistance of foodborne listeria monocytogenes.the objective of this study was to evaluate the susceptibility of 120 listeria monocytogenes strains isolated from food and food-processing environments to 19 antibiotics currently used in veterinary and human therapy. susceptibility tests were performed by using the automated vitek2 system. apart from penicillin, ampicillin and trimethoprim-sulfamethoxazole, for which clinical breakpoints for listeria susceptibility testing are defined according to the clinical and laboratory standard institute ...200919012982
the antimicrobial efficacy and structure activity relationship of novel carbohydrate fatty acid derivatives against listeria spp. and food spoilage microorganisms.novel mono-substituted carbohydrate fatty acid (cfa) esters and ethers were investigated for their antibacterial activity against a range of pathogenic and spoilage bacteria focussing on listeria monocytogenes. carbohydrate derivatives with structural differences enable comparative studies on the structure/activity relationship for antimicrobial efficacy and mechanism of action. the antimicrobial efficacy of the synthesized compounds was compared with commercially available compounds such as mon ...200919012983
contributions of six lineage-specific internalin-like genes to invasion efficiency of listeria monocytogenes.listeria monocytogenes strains are divided into at least three lineages, which seem to differ in virulence. internalins are surface-attached or secreted proteins that encode leucine-rich repeats, and l. monocytogenes encodes species-specific as well as lineage-specific internalin and internalin-like genes. internalins a and b have previously been shown to be critical for l. monocytogenes host cell invasion. transcription of selected internalins is regulated by the virulence gene regulator prfa a ...200919014275
the proinflammatory cytokine-induced irg1 protein associates with mitochondria.interferon-gamma (ifn-gamma) and tumor necrosis factor (tnf) are essential cytokines for successful clearance of microbial infections. activation of macrophages by synergistic effects of these cytokines leads to induction of antimicrobial effector systems like reactive oxygen and reactive nitrogen intermediates. strikingly, ifn-gammar(-/-) and tnfrp55(-/-) mice are considerably more susceptible to infections than inducible nitric oxide synthase(-/-) and p47phox(-/-) mice. thus we applied transcr ...200919014335
evaluation of a multiplex pcr system for simultaneous detection of salmonella spp., listeria monocytogenes, and escherichia coli o157:h7 in foods and in food subjected to freezing.conventional culture methods were compared to a multiplex polymerase chain reaction (pcr) assay for simultaneous detection of salmonella spp., listeria monocytogenes, and escherichia coli o157:h7 from enrichment cultures of various types of artificially inoculated and naturally contaminated foods. the multiplex pcr assay was evaluated in 44 types of spiked food samples, including meat, produce, fish, and dairy products targeting genes specific for each pathogen for simultaneous detection. the se ...200918991547
the role of l. monocytogenes serotype 4b gtca in gastrointestinal listeriosis in a/j mice.serotype 4b strains of listeria monocytogenes have been responsible for most large outbreaks of listeriosis. in l. monocytogenes serotype 4b, gtca and glta have been implicated in serotype-specific glycosylation of the teichoic acid of the cell wall with galactose and glucose. in this study, we investigated the impact of mutations in glta (resulting in absence of glucose on teichoic acid) and gtca (resulting in absence of galactose, and markedly reduced glucose on teichoic acid) on virulence fol ...200918991548
the ability of listeria monocytogenes pi-plc to facilitate escape from the macrophage phagosome is dependent on host pkcbeta.listeria monocytogenes are facultative intracellular pathogenic bacteria that can infect macrophages as well as non-professional phagocytes. after entry in the host cell, the bacteria escape from the phagosome into the cytoplasm. in murine macrophages and in cell lines derived from these cells, escape of l. monocytogenes from the phagosome is absolutely dependent on listeriolysin o (llo) and facilitated by a secreted phosphatidylinositol-specific phospholipase c (pi-plc). work in this laboratory ...200918996181
searching for the ideal cancer vaccine. 200919263513
cxcr4 is a key regulator of neutrophil release from the bone marrow under basal and stress granulopoiesis conditions.the number of neutrophils in the blood is tightly regulated to ensure adequate protection against microbial pathogens while minimizing damage to host tissue. neutrophil homeostasis in the blood is achieved through a balance of neutrophil production, release from the bone marrow, and clearance from the circulation. accumulating evidence suggests that signaling by cxcl12, through its major receptor cxcr4, plays a key role in maintaining neutrophil homeostasis. herein, we generated mice with a myel ...200919264920
toll-like receptor activity in recurrent aphthous ulceration.toll-like receptors (tlr) are membrane proteins that recognize conserved molecules derived from bacterial, virus, fungal or host tissues. activation of tlrs causes the production of cytokines that mediate inflammatory responses and drive t helper (th) 1 and 2 cell development. as an exaggerated th1 immune response is supposed to be involved in pathogenesis of recurrent aphthous ulceration (rau), we suggest that rau patients may have an imbalance in tlr pathways.200919267841
rapid detection of listeria monocytogenes in food by polymerase chain reaction.the standard conventional methods for the detection of listeria monocytogenes in foods require high time 7 to 10 days to give ready results. to dissolve this problem we have evaluate a short method using polymerase chain reaction (pcr) to analyze food samples. in parallel with this study, a comparison was made between pcr amplification from templates directly prepared from food and the official standard iso procedure 11290-1. in this study we have used a half frazer broth as an enrichment medium ...200919267993
intracellular bacterial infection and invariant nkt cells.the invariant (i) natural killer (nk)t cells represent a unique subset of t lymphocytes which express the v alpha 14 chain of the t cell receptor (tcr), that recognizes glycolipid antigens presented by the nonpolymorphic major histocompatibility complex (mhc) class i-like antigen presentation molecule cd1d, and they participate in protection against some microbial pathogens. although inkt cells have originally been regarded as t cells co-expressing nkr-p1b/c (nk1.1: cd 161), they do not seem to ...200919259343
sudden increases in listeriosis rates in england and wales, 2001 and 2003.the monthly incidence of listeriosis infections in england and wales had 2 sudden increases during april 2001 (41%) and march 2003 (48%). although no causative association is demonstrated, these increases correspond to key dates relating to the onset and aftermath of the 2001 foot and mouth disease outbreak in the united kingdom.200919239766
development of a hierarchical bayesian model to estimate the growth parameters of listeria monocytogenes in minimally processed fresh leafy salads.the optimal growth rate mu(opt) of listeria monocytogenes in minimally processed (mp) fresh leafy salads was estimated with a hierarchical bayesian model at (mean+/-standard deviation) 0.33+/-0.16 h(-1). this mu(opt) value was much lower on average than that in nutrient broth, liquid dairy, meat and seafood products (0.7-1.3 h(-1)), and of the same order of magnitude as in cheese. cardinal temperatures t(min), t(opt) and t(max) were determined at -4.5+/-1.3 degrees c, 37.1+/-1.3 degrees c and 45 ...200919239977
lmo1273, a novel gene involved in listeria monocytogenes virulence.listeria monocytogenes is a foodborne pathogen able to infect humans and many other mammalian species, leading to serious, often fatal disease. we have previously identified a five-gene locus in the genome of l. monocytogenes egd-e which comprised three contiguous genes encoding paralogous type i signal peptidases. in the present study, we focused on the two distal genes of the locus (lmo1272 and lmo1273), encoding proteins sharing significant similarities with the ylqf and rnhb proteins, respec ...200919246760
functional properties of novel protective lactic acid bacteria and application in raw chicken meat against listeria monocytogenes and salmonella enteritidis.in this study 635 lactic acid bacteria of food origin were evaluated for their potential application as protective cultures in foods. a stepwise selection method was used to obtain the most appropriate strains for application as protective cultures in chicken meat. specifically, all strains were examined for antimicrobial activity against various gram positive and gram negative pathogenic and spoilage bacteria. strains exhibiting anti-bacterial activity were subsequently examined for survival in ...200919249112
inactivated parapoxvirus ovis activates canine blood phagocytes and t lymphocytes.inactivated parapoxvirus ovis (ippvo) shows strong immunomodulatory activities in several species and is used in veterinary medicine as an immunostimulatory biological for the prevention and/or treatment of infectious diseases. in this study the immunostimulatory capacity of ippvo on the innate immune system was investigated in vitro by the evaluation of induction of the oxidative burst and modulation of phagocytosis by canine blood leukocytes (polymorphonuclear cells and monocytes) of dogs. in ...200919251383
temperature-dependent phage resistance of listeria monocytogenes epidemic clone ii.listeria monocytogenes epidemic clone ii (ecii) has been responsible for two multistate outbreaks in the united states in 1998-1999 and in 2002, in which contaminated ready-to-eat meat products (hot dogs and turkey deli meats, respectively) were implicated. however, ecological adaptations of ecii strains in the food-processing plant environment remain unidentified. in this study, we found that broad-host-range phages, including phages isolated from the processing plant environment, produced plaq ...200919251898
isolation, purification and de novo sequencing of tbd-1, the first beta-defensin from leukocytes of reptiles.a novel peptide with antimicrobial activity was isolated from leukocytes of the european pond turtle emys orbicularis and purified to homogeneity by preparative gel electrophoresis followed by reversed phase chromatography. it was highly active in vitro against escherichia coli, listeria monocytogenes, methicillin-resistant staphylococcus aureus, and candida albicans. the isolated peptide was sequenced de novo by tandem mass spectrometry using both collision-induced and electron-transfer dissoci ...200919253295
identification of potential on-farm sources of listeria monocytogenes in herds of dairy cattle.to elucidate the ecology of listeria monocytogenes on dairy cattle farms by determining the prevalence of the organism in various samples.200919254151
listeria monocytogenes sigmab modulates prfa-mediated virulence factor expression.listeria monocytogenes sigma(b) and positive regulatory factor a (prfa) are pleiotropic transcriptional regulators that coregulate a subset of virulence genes. a positive regulatory role for sigma(b) in prfa transcription has been well established; therefore, observations of increased virulence gene expression and hemolytic activity in a deltasigb strain initially appeared paradoxical. to test the hypothesis that l. monocytogenes sigma(b) contributes to a regulatory network critical for appropri ...200919255187
prevalence of listeria spp including listeria monocytogenes from apparently healthy sheep of gujarat state, india.a total of 1002 samples comprising blood (n = 248), faecal swabs (n = 248), nasal swabs (n = 248) and deep vaginal swabs (n = 248) collected from the 248 sheep and 10 environmental samples of 10 sheep flocks were examined for the presence of pathogenic listeria spp. confirmation of the isolates was based on biochemical tests followed by phenotypic characterization by haemolysis on sheep blood agar, christie atkins munch-petersen (camp) test phosphatidylinositol-specific phospholipase c (pi-plc) ...200919243567
role of cold shock proteins in growth of listeria monocytogenes under cold and osmotic stress conditions.the gram-positive bacterium listeria monocytogenes is a food-borne pathogen of both public health and food safety significance. it possesses three small, highly homologous protein members of the cold shock protein (csp) family. we used gene expression analysis and a set of mutants with single, double, and triple deletions of the csp genes to evaluate the roles of cspa, cspb, and cspd in the cold and osmotic (nacl) stress adaptation responses of l. monocytogenes. all three csps are dispensable fo ...200919151183
agrd-dependent quorum sensing affects biofilm formation, invasion, virulence and global gene expression profiles in listeria monocytogenes.the listeria monocytogenes agr peptide-sensing system has been analysed by creating a deletion mutant in agrd, the structural gene for the putative quorum-sensing peptide. the deltaagrd mutant displayed significantly reduced biofilm formation, a defect which could be restored by genetic or physical complementation. a reduced invasion of caco-2 intestinal epithelial cells was observed for the deltaagrd mutant while phagocytosis by thp-1 macrophages was unaffected. additionally, the level of inter ...200919154329
modeling the survival of escherichia coli o157:h7, listeria monocytogenes, and salmonella typhimurium during fermentation, drying, and storage of soudjouk-style fermented sausage.this study quantified and modeled the survival of escherichia coli o157:h7, listeria monocytogenes and salmonella typhimurium in soudjouk-style fermented sausage during fermentation, drying, and storage. batter prepared from ground beef (20% fat), seasonings, starter culture, and dextrose was separately inoculated with a multi-strain mixture of each pathogen to an initial inoculum of ca. 6.5 log(10) cfu/g in the batter. the sausages were subsequently fermented at 24 degrees c with a relative hum ...200919157610
different t cell receptor signals determine cd8+ memory versus effector development.following infection, naïve cd8+ t cells bearing pathogen-specific t cell receptors (tcrs) differentiate into a mixed population of short-lived effector and long-lived memory t cells to mediate an adaptive immune response. how the tcr regulates memory t cell development has remained elusive. using a mutant tcr transgenic model, we found that point mutations in the tcr beta transmembrane domain (betatmd) impair the development and function of cd8+ memory t cells without affecting primary effector ...200919164748
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