| bacteriophage typing of listeria species. | a bacteriophage typing scheme for differentiating listeria isolates from dairy products and various other foodstuffs was developed. sixteen selected phages isolated from both environmental sources and lysogenic strains were used for typing and, according to their lytic spectra, divided into four groups. thus far, 41 distinct patterns of lysis were seen when this set was used in typing 57 defined reference strains, representing all five confirmed species and 16 serotypes in addition to 454 lister ... | 1990 | 2116763 |
| behavior of listeria monocytogenes in the presence of gluconic acid and during preparation of cottage cheese curd using gluconic acid. | unrestricted or minimally restricted growth of listeria monocytogenes strain v7 occurred 1) at 13 degrees c in tryptose broth with .125 or .25% gluconic acid or .1 to .3% glucono-delta-lactone, 2) at 13 degrees c in milk with .125 to 1.0% gluconic acid or .5 or 1.0% glucono-delta-lactone, 3) at 35 degrees c in tryptose broth with .125 to .5% gluconic acid or .1 to 5% glucono-delta-lactone, and 4) at 35 degrees c in milk with .125 to 1.0% gluconic acid or .5 to 1.5% glucono-delta-lactone. limited ... | 1990 | 2117028 |
| listericidal activity of human neutrophil cathepsin g. | we demonstrate that cathepsin g, derived from human neutrophils, exhibits potent in vitro antimicrobial activity against listeria monocytogenes. cathepsin g listericidal activity was by a non-enzymic mechanism and was dependent on the cationic nature of the molecule. the listericidal activity of cathepsin g occurred in a manner that was both time-dependent and concentration-dependent. | 1990 | 2117044 |
| cytokines in antibacterial resistance: possible applications for immunomodulation. | acquired resistance to intracellular bacteria is primarily mediated by t cells which--by secreting multiple interleukins (ils)--activate antimicrobial activities in mononuclear phagocytes. experimental infection of mice with listeria monocytogenes and mycobacterium bovis has helped to clarify the role of ils in antimicrobial infection. these studies revealed: 1) application of ifn-gamma reduces the number of l. monocytogenes and treatment with anti-ifn-gamma antibodies worsens listeriosis; 2) in ... | 1990 | 2117103 |
| listeria monocytogenes moves rapidly through the host-cell cytoplasm by inducing directional actin assembly. | listeria monocytogenes is an intracellular parasite that can readily infect the macrophage-like cell line j774 and the kidney epithelial cell ptk2. after being ingested, the organism escapes from the phagolysosome into the host-cell cytoplasm. n-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-phallacidin, a specific stain for actin filaments (f-actin), demonstrates that within 1 hr of initiation of infection, the bacteria become surrounded by host-cell cytoplasmic actin filaments. by 3 hr, long projections ... | 1990 | 2117270 |
| human listeriosis, 1988. | | 1990 | 2117460 |
| cloning and characterization of t-cell-reactive protein antigens from listeria monocytogenes. | to explore the molecular basis of the t-cell-mediated immune response to listeria monocytogenes, we cloned and expressed listerial antigens in escherichia coli using the lambda-zap bacteriophage and bluescript plasmid vectors. a two-stage screening strategy was implemented to identify t-cell-reactive antigens; the first stage involved antibodies or oligonucleotide probes and the second stage was based on assays for t-cell activation. a library of genomic dna from l. monocytogenes was generated i ... | 1990 | 2117570 |
| listeria monocytogenes intragastric and intraperitoneal approximate 50% lethal doses for mice are comparable, but death occurs earlier by intragastric feeding. | the intraperitoneal (i.p.) and intragastric (i.g.) mouse approximate 50% lethal dose values (ald50s) were determined for 15 food and clinical isolates of listeria monocytogenes. although all strains gave i.g. ald50s comparable to or less than their i.p. ald50s, the i.g. feeding of most strains produced more deaths within the first 3 days of the 6-day test than did i.p. injection. ald50s ranged from 50 to 4.4 x 10(5) cells with approximately 1-log 95% confidence intervals. of five strains tested ... | 1990 | 2117576 |
| hemolysin is required for extraintestinal dissemination of listeria monocytogenes in intragastrically inoculated mice. | in this study we demonstrated that a hemolytic strain of listeria monocytogenes, but not a nonhemolytic mutant derived from it, translocated in substantial numbers to the mesenteric lymph nodes, spleen, and liver after intragastric inoculation of mice. growth at 4 degrees c prior to inoculation did not increase the virulence of the nonhemolytic mutant. these results indicate that hemolytic activity is required for the virulence of l. monocytogenes via the gastrointestinal tract, as has been show ... | 1990 | 2117581 |
| pharmacodynamics of trimethoprim-sulfamethoxazole in listeria meningitis: a case report. | infections in the cerebrospinal fluid (csf) occur in an area of impaired host defenses; therefore, bactericidal antibiotics that reach adequate concentrations in the csf are necessary for treatment. measurements of antibiotic penetration into the csf include csf inhibitory and bactericidal titers, the absolute antibiotic concentration in the csf, and the csf: serum concentration ratio. we present the case of a patient with listeria monocytogenes meningitis who failed to respond clinically to sta ... | 1990 | 2117750 |
| listeria species in a california coast estuarine environment. | listeria species and l. monocytogenes were found in 81 and 62%, respectively, of fresh or low-salinity waters (37 samples) in tributaries draining into humboldt-arcata bay, calif., during a winter (january-february) sampling period. the incidence of listeria species and l. monocytogenes in sediment (46 samples) from the same sites where water was sampled was 30.4 and 17.4%, respectively. one of three bay water samples contained listeria species (including l. monocytogenes), while of 35 samples o ... | 1990 | 2117874 |
| analysis of clinical and food-borne isolates of listeria monocytogenes in the united states by multilocus enzyme electrophoresis and application of the method to epidemiologic investigations. | to investigate the microbiology and epidemiology of the 1,700 sporadic cases of listeriosis that occur annually in the united states, we developed a multilocus enzyme electrophoresis (mee) typing system for listeria monocytogenes. we studied 390 isolates by mee. eighty-two electrophoretic types (ets) were defined. two distinct clusters of ets, et group a (etga) and et group b (etgb), separated at a genetic distance of 0.440, were identified. strains of etgb were associated with perinatal listeri ... | 1990 | 2117880 |
| use of a bacteriocin produced by pediococcus acidilactici to inhibit listeria monocytogenes associated with fresh meat. | a bacteriocin produced by pediococcus acidilactici had an inhibitory and bactericidal effect on listeria monocytogenes associated with fresh meat. mics were significantly lower than minimum killing concentrations. when meat was inoculated with l. monocytogenes, the bacteriocin reduced the number of attached bacteria in 2 min by 0.5 to 2.2 log cycles depending upon bacteriocin concentration. meat treated initially with the bacteriocin resulted in attachment of 1.0 to 2.5 log cycles fewer bacteria ... | 1990 | 2117881 |
| replica plating of colonies from listeria-selective agars to blood agar to improve the isolation of listeria monocytogenes from foods. | bacterial colonies from listeria-selective agars were replica plated to sheep blood agar to screen for beta-hemolysis. by using the replica plating method to test for the beta-hemolytic characteristic of all the colonies growing on listeria-selective agars instead of picking 3 to 10 suspected colonies for further testing, we recovered listeria monocytogenes from 59 of 142 listeria-selective agar plates which contained colonies of hemolytic and nonhemolytic listeria species and were negative when ... | 1990 | 2117884 |
| biological functions of mouse seminal vesicle fluid. ii. role of water-soluble fraction of seminal vesicle fluid as a nonspecific immunomodulator. | the suppressive mechanisms of t cells induced by water-soluble fraction of mouse seminal vesicle fluid (wsf-svf) were investigated to clarify its immunological roles in the reproductive immunity. wsf-svf inhibited the blastogenic responses to concanavalin a (con a) or phytohemagglutinin (pha) of t cells. pretreatment of splenocytes with wsf-svf did not suppress the blastogenesis of splenocytes to con a when treated cells were washed before cultures. wsf-svf did not inhibit the proliferation of c ... | 1990 | 2117909 |
| listeria monocytogenes endophthalmitis in a renal-transplant patient receiving ciclosporin. | endophthalmitis due to listeria monocytogenes developed suddenly in a 52-year-old man receiving immunosuppressive therapy for a renal transplantation carried out 2 months previously. the treatment combined low doses of ciclosporin and prednisone. the initial clinical picture was of acute hypertensive uveitis with hypopyon. despite prompt paracentesis and appropriate antibiotic therapy, the long-term course was unfavorable, and enucleation became necessary. the occurrence of listeriosis is classi ... | 1990 | 2118244 |
| immunotoxicity of bis(tri-n-butyltin)oxide in the rat: effects on thymus-dependent immunity and on nonspecific resistance following long-term exposure in young versus aged rats. | to investigate whether immune function suppression observed in an earlier study after short-term bis(tri-n-butyltin)oxide (tbto) exposure also occurred after long-term treatment, function studies for specific and nonspecific resistance were performed after exposure of weaned male rats to diets containing 0, 0.5, 5, or 50 mg tbto/kg for 4-6 and 15-17 months. treatment for 4.5 months had no effect on body weight but reduced thymus weight at 50 mg/kg. regarding the thymus-dependent immunity, delaye ... | 1990 | 2118283 |
| use of plasmid profiles and restriction endonuclease digest in environmental studies of listeria spp. from raw milk. | forty-eight isolates of listeria spp. (19 l. monocytogenes, 27 l. innocua, 2 l. welshimeri) from bulk raw milk were screened for plasmid dna. these isolates were collected over a period of 1 year. only l. innocua harboured plasmids (8/27 strains) which ranged in size 10-44 megadaltons. the plasmid bearing strains could be arranged into three groups 10 md, 44 md and 44 + 10 md. in two farms where listeria innocua were persistent in bulk raw milk different plasmids profiles were found (farm 1 and ... | 1990 | 2118791 |
| survival of pathogenic microorganisms in an egg-nog-like product containing 7% ethanol. | a liquor consisting of whole egg, saccharose (25% w/v) and ethanol (7.0% w/v) was artificially contaminated with salmonella enteritidis, s. typhimurium, staphylococcus aureus (three different strains), bacillus cereus and listeria monocytogenes. after 3 weeks of incubation at 22 degrees c the numbers of salmonella, s. aureus and l. monocytogenes decreased more than 3 log10 units. under such conditions, however, the total number of microorganisms increased 3 log10 units. at 4 degrees c the decrea ... | 1990 | 2118795 |
| the occurrence of listeria monocytogenes in cheese from a manufacturer associated with a case of listeriosis. | a case of listeriosis was associated with the consumption of a soft cheese produced in england. goats cheese and other products from the same food manufacturer were examined for the presence of listeria over the following 11 months. listeria monocytogenes was isolated from 16 of 25 cheese samples on retail sale, 12 of 24 cheese samples obtained directly from the factory, and from shelving within the plant. phage-typing of 68 isolates of l. monocytogenes from cheese samples and the factory showed ... | 1990 | 2118796 |
| microbiological quality of ayib, a traditional ethiopian cottage cheese. | one-hundred samples of ayib, a traditional ethiopian cottage cheese, were purchased from awassa market and analysed for their aerobic mesophilic counts, psychrotrophic counts, yeasts and molds, coliforms, spore-formers, enterococci, lactic acid bacteria. listeria monocytogenes, staphylococci and bacillus cereus. the majority of the samples showed counts of mesophilic aerobic bacteria, yeasts and enterococci of 10(8), 10(7) and 10(7) cfu/g. about 55% of the samples were positive for coliforms and ... | 1990 | 2118797 |
| the effect of ph, salt concentration and temperature on the survival and growth of listeria monocytogenes. | factorially designed experiments have been used to study the growth and survival of listeria monocytogenes in different combinations of ph and salt concentrations at ambient and chill temperatures. survival at low ph and high salt concentration was strongly temperature dependent. the minimum ph values that allowed survival after 4 weeks from an initial 10(4) cells were 4.66 at 30 degrees c, 4.36 at 10 degrees c and 4.19 at 5 degrees c. these limits were salt dependent, low (4-6%) salt concentrat ... | 1990 | 2118897 |
| efficacy of direct plating media for recovering listeria monocytogenes from foods. | studies were done to evaluate 14 direct plating media for their suitability to recover listeria monocytogenes strain scott a from pasteurized whole milk, chocolate ice cream mix, brie cheese and raw cabbage. healthy cells were inoculated into foods to achieve viable populations of 10(2), 10(4), or 10(6) cells/ml(g). bind's acriflavine agar, trypaflavine nalidixic acid serum agar, listeria transport enrichment agar, doyle and schoeni selective enrichment agar (dssea) and modified dssea were not s ... | 1990 | 2119210 |
| a comparative study of clinical and food isolates of listeria monocytogenes and related species. | ninety-six isolates of presumptive or confirmed listeria monocytogenes were obtained from local clinical (30 isolates) or food laboratories (66 isolates). minimal biochemical analysis identified only 80% of these isolates as l. monocytogenes the remaining included l. seeligeri, 1%, or the non-haemolytic l. innocua, 19%. the 27 clinical and 50 food isolates, mainly from meat products, frozen confectionaries, and cheeses, confirmed as l. monocytogenes were compared biochemically and serologically. ... | 1990 | 2120079 |
| effects of purified anti-lyt-2 mab treatment on murine listeriosis: comparative roles of lyt-2+ and l3t4+ cells in resistance to primary and secondary infection, delayed-type hypersensitivity and adoptive transfer of resistance. | mice treated with purified anti-lyt-2 monoclonal antibody (mab) displayed a delayed ability to eliminate a primary listeria monocytogenes infection from their spleens. elimination of listeriae from the liver was unimpaired by anti-lyt-2 mab treatment. treatment with anti-l3t4 mab, alone or in combination with anti-lyt-2 mab, resulted in similar increases in the numbers of listeriae recovered from the spleens at 7 days after challenge. listeria-infected mice that had been treated with anti-lyt-2 ... | 1990 | 2120126 |
| resistance to a non-immunogenic tumor, induced by corynebacterium parvum or listeria monocytogenes, is abrogated by anti-interferon gamma. | the complex processes that determine the outcome of the interaction of tumor and host were explored in the operationally simple and reproducible rat d-12 ascites tumor model. animals exhibit weak spontaneous resistance against this tumor that is not augmented by repeated inoculation, by various routes, of irradiated syngeneic d-12 tumor cells, but considerably enhanced after local administration of heat-killed corynebacterium parvum (cp) or listeria monocytogenes (lm) organisms. inoculation of c ... | 1990 | 2120139 |
| seasonal influence on murine immune function. | | 1990 | 2120711 |
| enhanced chemiluminescence elisa for listeria specific antigen in cerebrospinal fluid using an fitc-anti-fitc system. | an enzyme-linked immunosorbent assay (elisa) is described for the detection of a soluble listeria monocytogenes serogroup 4 antigen in cerebrospinal fluid samples (csfs). in the elisa an anti-listeria monoclonal antibody, immobilized onto assay wells, was used to capture antigen from csfs, the captured antigen was then reacted with a fluorescein isothiocyanate (fitc) conjugate of the same anti-listeria antibody, which was detected with a horseradish peroxidase conjugate of a monoclonal antibody ... | 1990 | 2120907 |
| western blot analysis of the antibody response in patients with listeria monocytogenes meningitis and septicemia. | the antibody response in patients with listeria monocytogenes septicemia and/or meningitis was investigated using western blot analysis (wba). protein antigen preparations were produced from two strains of listeria monocytogenes, representing serogroup 1 and 4, by sonication and differential centrifugation. igg antibodies from 8 (50%) of 16 patients with culture verified septicemia and/or meningitis due to listeria monocytogenes reacted with a 93 kda antigen from serogroup 1, in contrast to igg ... | 1990 | 2121484 |
| high-efficiency transformation of listeria monocytogenes by electroporation of penicillin-treated cells. | a procedure has been developed for electroporation-mediated transformation of listeria monocytogenes with plasmid dna. the method was optimized for intact cells of l. monocytogenes 23074 by determining the effects of field strength, cell density, and plasmid dna topology. transformation efficiencies were dramatically increased when cells were treated with penicillin. optimum frequencies of transformation (4 x 10(6) transformants/microgram dna) were obtained when cells were grown in 10 micrograms ... | 1990 | 2121618 |
| synthesis of species-specific stress proteins by virulent strains of listeria monocytogenes. | listeriolysin is a virulence factor that appears to be necessary for the intracellular survival of listeria monocytogenes. as shown in this investigation, listeriolysin is produced in only small amounts by clinical isolates of l. monocytogenes belonging to the serogroup 1/2a, but its synthesis can be induced by heat shock and to a lesser extent by oxidative stress. in addition to about 15 heat shock proteins that appear to be common to l. monocytogenes and listeria species that are nonpathogenic ... | 1990 | 2121648 |
| intracellular hemolysin-producing listeria monocytogenes strains inhibit macrophage-mediated antigen processing. | we found that virulent hemolysin-producing (hly+) listeria monocytogenes strains inhibit antigen processing and presentation when added to macrophages in vitro. a virulent hly- bacteria caused little or no inhibition. live hly+ bacteria inhibited presentation of both heat-killed l. monocytogenes and ovalbumin. several observations indicate that hemolysin produced by intracellular bacteria was responsible for the inhibition. first, inhibition was observed even when extracellular bacteria were rem ... | 1990 | 2121649 |
| direct blotting with viable cells of protein mixtures separated by two-dimensional gel electrophoresis. | a procedure is described which combines the high resolution power of two-dimensional (2d) gel electrophoresis with the advantage of direct probing with viable cells. this device permits the transfer by electroelution of 480 distinct fractions from a 2d gel into soluble phase. transferred fractions are virtually nontoxic, thus allowing direct probing with viable cells. using this procedure it was shown that t cells from normal healthy individuals recognized a multitude of mycobacterium tuberculos ... | 1990 | 2121829 |
| ingested listeria monocytogenes survive and multiply in protozoa. | listeria monocytogenes cells are ingested by protozoa such as acanthamoeba sp. or tetrahymena pyriformis. however, they are not killed, but survive within the protozoa and may multiply intracellularly. the protozoa are lysed within about 8 days, releasing viable l. monocytogenes. no co-existence was observed between l. monocytogenes and tetrahymena. a co-culture of l. monocytogenes and acanthamoeba sp. showed a decay of locomotive forms and release of listeria from vegetative protozoan cells whe ... | 1990 | 2121990 |
| gentamicin pharmacokinetics in neonates undergoing extracorporal membrane oxygenation. | we evaluated the effects of extracorporeal membrane oxygenation (ecmo) on the pharmacokinetics of gentamicin in 18 infants who underwent ecmo therapy for severe respiratory failure and received gentamicin for possible sepsis. twelve of these infants continued to receive gentamicin after ecmo had been discontinued. the volume of distribution (vd) of gentamicin in the newborns receiving ecmo was 0.58 +/- 0.04 liter/kg, compared with a vd of 0.45 +/- 0.02 liter/kg after ecmo had been discontinued ( ... | 1990 | 2122409 |
| identification of a gene that positively regulates expression of listeriolysin, the major virulence factor of listeria monocytogenes. | we have isolated, by molecular cloning and genetic complementation of a listeriolysin-negative mutant, a gene required for the expression of this virulence factor in listeria monocytogenes. the mutant strain slcc53, which was nonhemolytic and avirulent, harbored a deletion of 450 base pairs located approximately 1500 base pairs upstream of the listeriolysin gene. no transcripts corresponding to the listeriolysin gene were detected in the mutant. dna sequencing of this region from the hemolytic s ... | 1990 | 2122460 |
| [the potentiating action of listeria monocytogenes in relation to endotoxic shock]. | the infection of mice with listeria cells 15 hours prior to the inoculation of endotoxin sharply increased its lethal action. blood taken from the mice at the peak of the development of shock was toxic for adrenalectomized recipients. this potentiating effect was blocked by hydrocortisone. carrageenan prolonged the survival time of such animals, but did not change the course of endotoxin shock, as well as toxicosis, caused by listerial aqueous extract in adrenalectomized mice. this potentiating ... | 1990 | 2122620 |
| antibacterial activity of lactic acid bacteria isolated from vacuum-packaged meats. | lactic acid bacteria isolated from vacuum-packaged fresh meat stored at 4 degrees c were shown to produce antagonistic substances active against closely related bacteria. growth medium, ph and growth temperature all affected the production of the inhibitory substances. ten strains including aciduric lactobacillus-type organisms, carnobacterium spp. and leuconostoc spp. were selected that produced protein-aceous substances that caused inhibition of indicator strains. these were considered to be b ... | 1990 | 2123171 |
| studies on cytokine activation of listericidal activity in murine macrophages. | the ability of a variety of soluble factors, alone or in combination, to endow murine resident peritoneal macrophages with listericidal activity was assessed. inhibition of growth and (or) killing of listeria in infected macrophages was determined by the uptake of [3h]uracil following lysis of the infected macrophage monolayers. interferon-gamma was shown to induce modest listericidal activity in murine resident macrophages as compared with untreated monolayers. treatment with tumour necrosis fa ... | 1990 | 2123733 |
| petite colony formation by listeria monocytogenes and listeria species grown on esculin-containing agar. | several strains of listeria species formed petite-sized colonies from parent stock cultures when grown on agar media containing 0.2-1% (w/v) esculin. this was observed in listeria monocytogenes (7/22 strains), l. innocua (1/3), l. grayi (1/1), l. seeligeri (1/3), and l. welshimeri (1/1), but not in l. ivanovii (0/1) and l. murrayi (0/1). this phenomenon was only observed on agar media that contained esculin. all petite isolates had biotyping profiles identical to their larger, normal-sized count ... | 1990 | 2123734 |
| interleukin-1-induced promotion of t-cell differentiation in mice immunized with killed listeria monocytogenes. | we studied the effects of administration of recombinant interleukin-1 alpha (ril-1 alpha) to mice after immunization with killed listeria monocytogenes cells on the promotion of the functional differentiation of t cells in vivo. mice immunized with killed l. monocytogenes were unable to express cell-mediated immunity to specific antigen in vivo, as determined by delayed-type hypersensitivity (dth) and acquired cellular resistance (acr), and splenic t cells obtained from such mice were unable to ... | 1990 | 2123829 |
| nonhemolytic listeria monocytogenes mutants that are also noninvasive for mammalian cells in culture: evidence for coordinate regulation of virulence. | we identified nonhemolytic mutants of listeria monocytogenes that were severely deficient in their ability to invade mammalian nonprofessional phagocytes. these mutants were generated spontaneously or by means of transposon tn916 mutagenesis. in terms of their extracellular proteins, the noninvasive mutants were deficient not only in the sulfhydryl-activated hemolysin (listeriolysin) but also in an antigenically unrelated extracellular protein with an apparent molecular weight of 32,000 which co ... | 1990 | 2123830 |
| in vitro antimicrobial susceptibility of listeria monocytogenes isolated in the uk and other listeria species. | the mics and mbcs of 21 antimicrobial agents were determined for 103 strains of listeria monocytogenes isolated in the uk and 27 strains of other listeria species. ampicillin, penicillin, azlocillin, imipenem, gentamicin, netilmicin, amikacin, erythromycin, rifampicin, trimethoprim, clindamycin and vancomycin had good activity, while cephalothin, chloramphenicol, ciprofloxacin and ofloxacin were less active, and cefuroxime, enoxacin, norfloxacin and fosfomycin were the least active. tetracycline ... | 1990 | 2124539 |
| sensitivity of listeria monocytogenes to irradiation. | irradiation of listeria monocytogenes was carried out in culture media and pork meat paste at room temperature with 60co radiation source of 6.6 kgy.h-1 dose rate. the employed doses were 0, 0.5, 1, 2, 3, 4 and 6 kgy. because of the expected great number of injured cells, parallel to the direct counting at selective media, liquid as well as solid resuscitation methods were used. one strain of out 3 survived as high as 4 kgy irradiation. radiation with 2 kgy resulted 7 log cycles reduction of cel ... | 1990 | 2124763 |
| antibody response of dairy cattle experimentally infected with listeria monocytogenes. | the purpose of our study was to monitor the humoral immune response of 34 lactating dairy cattle experimentally infected with listeria monocytogenes (strain scott a, serotype 4b). twenty-seven animals were inoculated with 10(6) to 10(7) c.f.u./ml of l. monocytogenes via the intramammary route at ten day intervals for one month and 7 were inoculated with 4 x 10(2) to 4 x 10(3) c.f.u./ml. preinfection and weekly-post infection serum and whey samples were prepared during acute infection. antibody t ... | 1990 | 2124764 |
| study of listeria monocytogenes survival during the preparation and the conservation of two kinds of dairy product. | we tested yoghurts and soft cheeses for survival of listeria monocytogenes during their manufacture and their storage at 4 degrees c. in yoghurt, even when the concentration of germs is high, the bacterial population decreased rapidly and the life of time of l. monocytogenes in this product depends on the sample acidity. the microorganisms disappear when the ph falls to 3.5. in soft white cheeses, only a fabrication with chemical and bacterial ferments allows an acidity which is compatible with ... | 1990 | 2124765 |
| comparison of allergenic skin test with serological and bacteriological examinations of cattle for listeria monocytogenes. | five herds, each containing 200 to 300 cows, were surveyed for listeriosis. since listeriosis is predominantly linked to reproductive diseases in the surveyed area, suspected cows were first selected according to the records on their previous reproductive disorders such as abortion, endometritis and sterility. by simultaneous serological, bacteriological and skin allergenic testing 40 cows suffering from listeriosis were detected. but, only seven of those cows were occasionally shedding listeria ... | 1990 | 2124766 |
| haematological reactions of rabbits infected intravenously with listeria strains of different virulence. | listeria strains of different virulence were injected intravenously into rabbits of both sexes (2-4 kg). the infectious dose was 10(8) cells/kg. blood samples were taken from the ear wein one day and immediately before the infection, then 3 h, 1, 2, 3, 6 and 10 days after it. total white blood cell counts and their changes were determined and the number of lysosomal granules in neutrophils were counted. a marked monocytic reaction was observed after the injection of virulent listeria monocytogen ... | 1990 | 2124767 |
| [listeriosis in newborn infants]. | listeriosis of the newborn is a relatively rare disease, presenting with clinical signs of septicemia. early onset disease, resembling group b streptococcal septicemia, is already transmitted from the mother to the fetus and is associated with high morbidity and mortality. late onset septicemia occurs as sporadic or as epidemic disease, usually beyond the fifth day of life. epidemics can be caused by consumption of contaminated food or by nosocomial infections in neonatal units. phage typing off ... | 1990 | 2125091 |
| isolation of listeria monocytogenes from raw milk and its environment at dairy farms in japan. | the incidence of listeria monocytogenes contamination in raw milk from farm bulk tanks and silage was investigated monthly at 20 dairy farms in aomori prefecture, japan, from january to july in 1989. listeria sp. was isolated from one sample (5%) of raw milk collected in may, but l. monocytogenes was not isolated from raw milk. l. monocytogenes was isolated from two samples of silage (10%) collected in june. silage, cow feces, sawdust bedding, dust and soil in these farms were tested for listeri ... | 1990 | 2125110 |
| detection of listeria monocytogenes in foods by immunomagnetic separation. | immunomagnetic separation with immunomagnetic beads was used to isolate strains of listeria monocytogenes both from pure cultures and from heterogeneous suspensions. the monoclonal antibodies used recognized all six strains of serotype 4 but only one of three strains of serotype 1. coating procedure, incubation time, and number of immunomagnetic beads influenced the sensitivity of the isolation method. less than 1 x 10(2) bacteria per ml in pure cultures and less than 2 x 10(2) bacteria per ml i ... | 1990 | 2125186 |
| actin filament nucleation by the bacterial pathogen, listeria monocytogenes. | shortly after listeria is phagocytosed by a macrophage, it dissolves the phagosomal membrane and enters the cytoplasm. 1 h later, actin filaments coat the listeria and then become rearranged to form a tail with which the listeria moves to the macrophage surface as a prelude to spreading. if infected macrophages are treated with cytochalasin d, all the actin filaments associated with the listeria break down leaving a fine, fibrillar material that does not decorate with subfragment 1 of myosin. th ... | 1990 | 2125302 |
| new method for the isolation of listeria monocytogenes from contaminated samples. | a new method for the isolation of listeria monocytogenes from samples contaminated with other bacteria is described. the method requires 10 to 11 days and is based on the motility of listeriae in semisolid selective medium. the new method was compared with isolation techniques described by füzi and pilis and by ralovich et al. all 30 faecal samples containing 100 listeriae per g of faeces were shown positive by the new method. using the method of ralovich et al. the same positivity ratio could b ... | 1990 | 2125396 |
| penicillin binding proteins in listeria monocytogenes. | membranes of listeria were obtained from protoplasts and treated with 125i-ampicillin as probe, at different concentrations. eight bands, corresponding to proteins labelled with the probe were detected their molecular weight ranged from 38,000 to 100,000, being the predominant ones at 95,000; 85,000; 60,000; 49,000 and 38,000. the copy number of each pbp was also estimated. by means of competitive experiments the binding pattern of ampicillin, mecillinam, piperacillin, cefalotin, cefaloridine, c ... | 1990 | 2125398 |
| septic arthritis due to listeria monocytogenes. | | 1990 | 2125627 |
| enhanced thermal destruction of listeria monocytogenes and staphylococcus aureus by the lactoperoxidase system. | the lactoperoxidase system (lps) enhanced thermal destruction of listeria monocytogenes and staphylococcus aureus. after lps activation, biphasic survival curves were observed for l. monocytogenes at 57.8 degrees c and for s. aureus at 55.2 degrees c. the data were consistent with a model that assumed two bacterial populations differing in heat sensitivity. the more heat-sensitive fractions (93% of the l. monocytogenes, 92% of the s. aureus) were killed almost instantly. for these biphasic survi ... | 1990 | 2125815 |
| catalase, superoxide dismutase, and hemolysin activities and heat susceptibility of listeria monocytogenes after growth in media containing sodium chloride. | the activities of catalase, superoxide dismutase, and a thiol-activated hemolysin produced by four strains of listeria monocytogenes propagated in media containing various concentrations of sodium chloride were examined. l. monocytogenes 7644 showed an increase in catalase, superoxide dismutase, and thiol-activated hemolysin activities when grown in a medium containing 2.5% (wt/vol) nacl followed by a decrease in activities when propagated in media containing salt concentrations higher than 2.5% ... | 1990 | 2125816 |
| detection of listeria monocytogenes by using the polymerase chain reaction. | a method was developed for detection of listeria monocytogenes by polymerase chain reaction amplification followed by agarose gel electrophoresis or dot blot analysis with a 32p-labeled internal probe. the technique identified 95 of 95 l. monocytogenes strains, 0 of 12 listeria strains of other species, and 0 of 12 non-listeria strains. | 1990 | 2125817 |
| listeria monocytogenes contamination of crops grown on soil treated with sewage sludge cake. | listeria monocytogenes was found in the sewage sludge cake which is commonly used as an agricultural fertilizer in iraq. soils treated with this material were contaminated with the organism. pot and field experiment showed that crops grown on treated soil became contaminated with l. monocytogenes and when alfalfa plant was grown on farmland soil treated with sewage sludge cake, listerias were found on 10% of 50 plants sampled at harvest, but the organism was detected only in low numbers on these ... | 1990 | 2126004 |
| antimicrobial activity of leuconostoc gelidum against closely related species and listeria monocytogenes. | a newly isolated strain of leuconostoc gelidum was evaluated for its ability to inhibit a wide spectrum of lactic acid bacteria, meat spoilage bacteria and food-related human pathogens, including listeria monocytogenes. it was inhibitory to most of the lactobacilli, all the leuconostocs, and three strains of l. monocytogenes when tested both by direct and well diffusion methods. cell-free extract retained activity after 60 min at 100 degrees c but was sensitive to protease. dialysis suggested a ... | 1990 | 2126005 |
| an investigation of indirect conductimetry for detection of some food-borne bacteria. | indirect conductimetry using a rapid automated bacterial impedance technique was investigated. strains of staphylococcus aureus, listeria monocytogenes, enterococcus faecalis, bacillus subtilis, escherichia coli, pseudomonas aeruginosa, aeromonas hydrophila and salmonella spp. grown in whitley impedance broth all elicited indirect conductimetric changes. these indirect conductance responses were improved by the addition of 2 g/l glucose to the medium and resulted in maximum changes of 2340-4300 ... | 1990 | 2126006 |
| suppression of host resistance against listeria monocytogenes infection by 15-deoxyspergualin in mice. | the effects of 15-deoxyspergualin (dsg), an immunosuppressive agent, on host resistance against listeria monocytogenes were studied in mice. administration of dsg in the early phase of infection resulted in fatal listeriosis by preventing acquired anti-listerial resistance, even though the infectious dose was sublethal for the untreated controls. in contrast, dsg treatment started after development of the acquired immunity was ineffective. endogenous production of interferon-gamma (ifn-gamma) an ... | 1990 | 2126253 |
| growth of listeria monocytogenes scott a, serotype 4 and competitive spoilage organisms in raw chicken packaged under modified atmospheres and in air. | the development of listeria monocytogenes scott a, serotype 4 and aerobic plate counts on minced raw chicken were determined independently at 4, 10 and 27 degrees c. samples were packaged in flexible film under two modified atmospheres (one containing oxygen and one containing no oxygen) or air. the anaerobic modified atmosphere (75:25, co2:n2) resulted in the failure of both the aerobic plate counts and l. monocytogenes to grow at all temperatures. both the l. monocytogenes and aerobic plate co ... | 1990 | 2126442 |
| fate of listeria monocytogenes in orally dosed chicks. | the fate of listeria monocytogenes in chicks perorally dosed with these bacteria at 2 days of age was determined by bacterial enumeration, immunoperoxidase staining and histological examination of the liver, muscle and gastrointestinal tract. results revealed listerial egress from the digestive tract and elimination of the organism from the body in most of the chicks within 9 days post-inoculation. l. monocytogenes was isolated from the caecum of only one of 10 chicks examined at 4 weeks post-in ... | 1990 | 2126445 |
| effect of temperature and ph on survival of listeria monocytogenes in coleslaw. | the survival and growth of listeria monocytogenes in fresh coleslaw, ph 3.9, and in coleslaw adjusted to ph 4.0, 5.0, 6.0 or 7.0 before inoculation was studied at three temperatures (4, 15 and 25 degrees c). l. monocytogenes was not detectable after 5 days incubation in fresh coleslaw nor in coleslaw adjusted to ph 4.0. coleslaw at ph 5.0 was also inhibitory to l. monocytogenes at all three temperatures studied. a decline in viable numbers of l. monocytogenes in coleslaw at ph 6.0 occurred at 4 ... | 1990 | 2126448 |
| [antigen detection for the diagnosis of bacterial meningitis using the latex agglutination test]. | in this study, etiologic agents were investigated by using routine and latex agglutination test (la) methods, in the cerebrospinal fluid (csf) samples taken from 31 patients who were admitted to various clinics of ankara numune hospital with suspected meningitis. in the culture tests of 31 purulent csf samples, 6 positive (19.4%) and 25 negative results were obtained. in 13 cases (41.9%) etiologic agents were observed by means of the gram-stained smear of the csf sediments. la test was applied t ... | 1990 | 2126593 |
| alteration of pbp 3 entails resistance to imipenem in listeria monocytogenes. | a mutant with decreased susceptibility to imipenem (ipr) was selected in vitro from a susceptible clinical isolate of listeria monocytogenes (ips). ipr exhibited decreased susceptibility to penicillin g (4 x mic) and imipenem (16 x mic) and increased susceptibility to cefotaxime (0.25 x mic). electrophoretic profiles of membrane proteins and penicillin-binding proteins (pbps) were identical in the two strains; each strain had five pbps with molecular masses of ca. 97, 83.3, 81, 77.1, and 42.6 ki ... | 1990 | 2126687 |
| incidence and characterization of listeria monocytogenes in foods available in taiwan. | a variety of foods were examined for the incidence of listeria monocytogenes, and the bacterial isolates were further characterized. l. monocytogenes was selected on licl-phenylethanol-moxalactam agar after enrichments and identified by several biochemical, mobility, and camp tests. l. monocytogenes was isolated from 58.8% of pork samples, 50% of chicken carcasses, 38% of turkey parts, 34% of frozen semiready foods, 24% of beef steaks, 12.2% of vegetables, 10.5% of seafoods, and 4.4% of frozen d ... | 1990 | 2126699 |
| highly selective medium for isolation of listeria monocytogenes from food. | a new selective medium (al-zoreky-sandine listeria medium [aslm]) was formulated to recover listeria monocytogenes from food specimens; the medium completely inhibited common food microflora. recognition of listeria colonies is evident by black discoloration of the medium due to esculin hydrolysis without need for special illuminating equipment. the medium contains acriflavin, ceftazidime, and moxalactam as selective agents. compared with listeria selective agar, aslm was equally effective in re ... | 1990 | 2126701 |
| thermotolerance of listeria monocytogenes and salmonella typhimurium after sublethal heat shock. | the effect of prior heat shock on thermotolerance of listeria monocytogenes and salmonella typhimurium in broth culture was determined. bacteria were grown at the permissive temperature of 35 degrees c, sublethally heated at 35 (control), 42, 48, and 52 degrees c (nonpermissive control) for various times, and inactivated at either 57.8 or 52 degrees c. the induction of increased thermotolerance by heat shock, although consistent within each experiment, was generally not significant for l. monocy ... | 1990 | 2126703 |
| [listeria monocytogenes: a rare etiology of infection of ascitic fluid that can be asymptomatic]. | | 1990 | 2127030 |
| growth inhibition of selected food-borne bacteria, particularly listeria monocytogenes, by plant extracts. | six extracts from chinese medicinal plants: tin men chu, sey lau pai, siu mao heung, bak tao yung, kam chin chiu and liao ya, were tested for their inhibitory effect on selected food-borne bacteria by the well assay technique. among them, tin men chu, siu mao heung and sey lau pai inhibited the growth of staphylococcus aureus, klebsiella pneumonia, escherichia coli, shigella flexneri, streptococcus faecalis, salmonella paratyphi, salm. enteritidis, enterobacter aerogenes, pseudomonas fluorescens ... | 1990 | 2127264 |
| listeriosis--the therapeutic options. | | 1990 | 2127775 |
| cloning of the listeriolysin o gene and development of specific gene probes for listeria monocytogenes. | a clone containing 3.1 kb of listeria dna was selected from a gene library of listeria monocytogenes scott a strain. the escherichia coli clone produced hemolysin on sheep blood agar and in sonicated extracts but very little in the culture supernatant. this 3.1-kb dna fragment and a 650-bp hindiii fragment located within the listeriolysin gene were used as probes in a colony hybridization assay. both probes were specific for l. monocytogenes and did not hybridize with any other listeria strains ... | 1990 | 2128013 |
| in vivo administration of anti-asialo-gm1 antibody enhances splenic clearance of listeria monocytogenes. | resistance of mice to infection by listeria monocytogenes involves a biphasic response. the first phase consists of the first 48 h after infection, during which there is multiplication of listeria in the liver and spleen of infected mice. in these nonimmune mice, macrophages and polymorphonuclear leukocytes are the effector cells involved in controlling multiplication. in the second phase, cell-mediated immunity develops, beginning on day 2, during which multiplication of listeria is prevented b ... | 1990 | 2128370 |
| suppression of blastogenic transformation of lymphocytes by bacteroides fragilis in vitro and in vivo. | bacteroides species and enterobacteriaceae are known to cause synergistic infections. however, the mechanisms behind this synergy are not completely understood. several authors have shown that bacteroides species may inhibit the phagocytosis of enterobacteriaceae by polymorphonuclear leukocytes as well as by macrophages. with the present study we have addressed the question of whether bacteroides fragilis (bf) is also capable of suppressing specific immune functions. when incubated together with ... | 1990 | 2128603 |
| [the seroprevalence of listeria infections without clinical sign in a population of pregnant women from the reus area]. | we describe the results of a study of asymptomatic listeria monocytogenes serum prevalence in a population of pregnant women in the reus area. the study includes newborn exam and correlation with laboratory data obtained by an indirect immunofluorescence method recently developed. the incidence of anti-listeria antibody carriers was high (12%) but in no cases spontaneous abortions or fetal malformations were associated to high titers. | 1990 | 2128653 |
| ultrastructural changes in some pathogenic bacteria after treatment with ethylendiamintetraacetic acid. | the ultrastructure of pseudomonas pseudomallei, pseudomonas aeruginosa. yersinia pseudotuberculosis, salmonella typhimurium, listeria monocytogenes was studied after treatment with edta. the study established that the most sensitive species were: pseudomonas pseudomallei and pseudomonas aeruginosa. in the case of listeria monocytogenes changes were not observed. typical ultrastructural changes in the cell wall and the cytoplasmic membrane were established by means of ultrathin sections, as well ... | 1990 | 2129076 |
| fate of listeria monocytogenes during the manufacture and ripening of parmesan cheese. | parmesan cheese was made from a mixture of pasteurized whole and skim milk that was inoculated to contain ca. 10(4) to 10(5) cells of listeria monocytogenes/ml. curd was cooked at 51 degrees c (124 degrees f) for ca. 45 min. during cheese making, maximum numbers of l. monocytogenes appeared just before cooking; at this point, the increase over initial numbers was a .61 to 1.0 order of magnitude. during cooking of curd, the average decrease in numbers of l. monocytogenes was a .22 order of magnit ... | 1990 | 2129167 |
| changes in populations of listeria monocytogenes in a medium with internal ph control containing streptococcus cremoris. | behavior of listeria monocytogenes in a commercial starter culture medium with internal ph control was examined. the ipcm-1 medium was inoculated with l. monocytogenes (strain v7, scott a, or california) at ca. 10(3) cfu/ml and streptococcus cremoris (.25%, 1.6 x 10(5) or 1.0%, 8.6 x 10(5) cfu/ml) and was incubated at 21 or 30 degrees c for 30 h. the ph of the uninoculated medium and control (l. monocytogenes only) was between 6.8 and 7.0 before and after incubation. the area on a figure between ... | 1990 | 2129168 |
| efficiency of sanitizing agents for destroying listeria monocytogenes on contaminated surfaces. | in an effort to control the potential hazard of dairy product contamination by contact with processing surfaces, the efficiency of four commercial sanitizing agents was evaluated using the aoac use-dilution method for their bactericidal activity at 4 and 20 degrees c against listeria monocytogenes strain scott-a attached on four types of surfaces (stainless steel, glass, polypropylene, and rubber). our results indicate that all sanitizers tested were more efficient against l. monocytogenes attac ... | 1990 | 2129169 |
| treatment with anti-tumor necrosis factor alpha does not influence the immune pathological response against lymphocytic choriomeningitis virus. | the role of tumor necrosis factor alpha (tnf alpha) in the immunopathological events induced by infection with lymphocytic choriomeningitis (lcm) virus (lcmv) was assessed by treatment of c57bl/6 mice with a sheep antibody to murine tnf alpha antiserum to strongly interfere with anti-listeria host defense. however, despite its effectiveness in listeria infections in vivo, antibody to tnf alpha used at 6 x 10(4) neutralizing units per day subcutaneously had no detectable influence on the kinetics ... | 1990 | 2129499 |
| [listeriosis as an infection of food origin]. | after analysing the etiopathogenesis and transmission process of the microorganism, the authors have examined the latest and documented outbreaks owing to food-borne strains of listeria monocytogenes in europe and in north america. the considered studies indicate an increase of listeriosis cases caused by infected food, especially food of animal origin, such as meat and milk-dairy products. | 1990 | 2133320 |
| comparative in vitro activity of the new erythromycin derivative dirithromycin against gram-positive bacteria isolated from cancer patients. | the in vitro activity of dirithromycin (ly-237216), a new macrolide erythromycin derivative, was compared to that of four other agents (clarithromycin, erythromycin, roxithromycin, clindamycin) against 334 gram-positive isolates obtained from cancer patients. dirithromycin was similar in potency and antimicrobial spectrum to the other agents tested. it was very active against beta-haemolytic streptococci and streptococcus pneumoniae, and moderately active against penicillin and methicillin susce ... | 1990 | 2137413 |
| mice vaccinated with a non-virulent, aromatic-dependent mutant of salmonella choleraesuis die from challenge with its virulent parent but survive challenge with salmonella typhimurium. | balb/c mice given a live vaccine of an aroa mutant of salmonella choleraesuis by intraperitoneal (i.p.) injection were not protected against i.p. challenge with its virulent parental strain but were protected against i.p. challenge with either of two virulent strains of salmonella typhimurium (o [1], 4, [5], 12). vaccination with a live vaccine of s. typhimurium aroa protected against challenge with s. typhimurium but not with s. choleraesuis. intraperitoneal administration of either aroa strain ... | 1990 | 2139129 |
| [listeria monocytogenes endocarditis in a patient with mechanical valve prosthesis]. | | 1990 | 2139221 |
| in-vitro studies with ramoplanin (mdl 62,198): a novel lipoglycopeptide antimicrobial. | ramoplanin is a novel lipoglycopeptide antimicrobial complex, isolated from the fermentation products of a strain of actinoplanes sp. (atcc 33076), which comprises three closely related polypeptides, each containing chlorinated phenyl moieties and d-mannose. the in-vitro activity of ramoplanin was compared with those of vancomycin and teicoplanin. ramoplanin was very active against staphylococcus spp., irrespective of methicillin susceptibility, with all isolates inhibited by 1 mg/l or less. con ... | 1990 | 2139436 |
| docosahexaenoic acid, a constituent of rodent fetal serum and fish oil diets, inhibits acquisition of macrophage tumoricidal function. | macrophage (m phi) activation is deficient in the fetus and neonate, at times when the serum concentration of docosahexaenoic acid (dha; 22:6n3) is approximately 10-fold higher than in the adult. we tested the effects of highly purified dha on m phi activation in vitro. m phi were stimulated with rifn-gamma plus either of two second or "triggering" signals, lps or heat-killed listeria monocytogenes. m phi activation was assayed as the lysis of p815 mastocytoma cells, which are resistant to tnf-a ... | 1990 | 2141046 |
| target cell lysis and il-2 secretion by gamma/delta t lymphocytes after activation with bacteria. | peripheral blood t lymphocytes from healthy donors were stimulated with mycobacterium tuberculosis in vitro and afterward analyzed phenotypically. marked expansion of the gamma/delta t cell population (3- to 21-fold) was observed in 15/21 donors 7 to 10 days after stimulation. in addition to m. tuberculosis, mycobacterium leprae (six of eight) as well as the gram-positive bacteria, staphylococcus aureus (two of six), group a streptococci (seven of nine), and listeria monocytogenes (four of eight ... | 1990 | 2145360 |
| [listeria monocytogenes liver abscess. in a diabetic patient]. | most liver abscesses are caused by enterobacteriaceae, sometimes associated with anaerobes. listeriosis is an exceptional cause of liver abscess, usually in a context of disseminated infections. we report the case of a diabetic woman who had liver abscess due to listeria monocytogenes. the organism was isolated after guided needle aspiration, and there was no other site of infection. the course of the disease gradually moved towards recovery under an antibiotic therapy that was based on sensitiv ... | 1990 | 2146666 |
| presentation of listeria monocytogenes to cd8+ t cells requires secretion of hemolysin and intracellular bacterial growth. | cell-mediated immunity to listeria monocytogenes (lm) involves both cd4+ and cd8+ t cell responses. an important virulence factor in the pathogenesis of infection and development of protective immunity to lm is secretion of the sulfhydryl-activated hemolysin (hly), listeriolysin. listeria secretion of hly allows lm to escape the endosomal compartment and enter the cytosol of the cell where intracellular growth can occur. we developed a system using bone marrow macrophages cultured in csf-1 or if ... | 1990 | 2147195 |
| [early onset neonatal septicemia caused by listeria monocytogenes]. | listeria monocytogenes can cause sepsis and meningitis during the neonatal period. six cases of early onset neonatal sepsis caused by listeria monocytogenes are reported here. these cases were diagnosed in a private hospital at santiago, chile from december 1984 throughout november 1986. the incidence rate was 1.4 x 1,000 liveborns. clinical findings included prematurity (6), meconium stained amniotic fluid (6), hepatomegaly (6), splenomegaly (6), maculopapular exanthem (4), anal prolapse (3) an ... | 1990 | 2152219 |
| [listeriosis in the adult. clinical, epidemiological, and therapeutic considerations based on a series of 26 cases]. | the clinico-epidemiological characteristics and therapy in 26 patients with infection produced by listeria monocytogenes were reported. in 14 cases there was a primary bacteremia and in 12 patients there was a meningeal involvement. in 22 patients a previous disease was detected. chronic immunosuppressor therapy was present in 13 cases. the most common symptom was the fever associated with meningeal syndrome, decreased consciousness and or focal neurologic involvement in cases with meningitis. i ... | 1990 | 2152476 |
| effects of exposure to benzene in vivo on the murine mononuclear phagocyte system. | exposure to benzene has been shown to decrease resistance to challenges by listeria monocytogenes or tumor cells in mice. alterations of t-lymphocytes have been suggested as one probable cause. macrophages are also critical participants in resistance to listeria and to tumor cells. we have previously shown that exposure of macrophages in vitro to benzene metabolites, but not to benzene, inhibited several functions of macrophages that are critical for host resistance. the present studies were con ... | 1990 | 2158675 |
| adherence of a virulent strain of listeria monocytogenes to the surface of a hepatocarcinoma cell line via lectin-substrate interaction. | listeria monocytogenes was examined for the presence of surface carbohydrates to ascertain whether surface sugars, if present, would interact with eucaryotic surface carbohydrate receptors. we found that a virulent, but not two avirulent strains had a surface alpha-d-galactose residue as determined by agglutination with griffonia simplicifolia (gs-i) and other lectins. the virulent strain bound to a human hepatocarcinoma cell line (hepg2), which has a well characterized receptor for alpha-d-gala ... | 1990 | 2159270 |
| insertional mutagenesis of listeria monocytogenes with a novel tn917 derivative that allows direct cloning of dna flanking transposon insertions. | to carry out efficient insertional mutagenesis in listeria monocytogenes and to facilitate the characterization of disrupted genes, two novel derivatives of tn917 were constructed, tn917-ltv1 and tn917-ltv3. the derivatives (i) transpose at a significantly elevated frequency, (ii) generate transcriptional lacz fusions when inserted into a chromosomal gene in the appropriate orientation, and (iii) allow the rapid cloning in escherichia coli of chromosomal dna flanking transposon insertions. the r ... | 1990 | 2163385 |
| augmentation of host defense against listeria monocytogenes infection by oral administration with polysaccharide rbs (ron). | protection against listeria monocytogenes in mice was enhanced by oral administration with a 30 mg/kg/day dose of polysaccharide rbs for 10 days. in mice treated with rbs, an enhanced elimination in vivo of l. monocytogenes was observed at the relatively late phase of listerial infection in correlation with enhanced immune responses against l. monocytogenes. the peritoneal macrophages from mice treated with rbs exhibited an increased activity of accessory cells for immune responses as assessed b ... | 1990 | 2167878 |
| selective potentiation of host resistance in mice following treatment with pyrexol. | the purpose of this study was to examine the effect of treatment with the biologic response modifier pyrexol on murine host resistance to various infectious organisms. adult female cd1 mice were treated with a single subcutaneous 100-micrograms injection of pyrexol at 14, 7, 5, 2, or 1 day prior to infection with various infectious organisms. these organisms included the herpes simplex type 2 and influenza viruses, as well as the bacteria listeria monocytogenes and streptococcus zooepidemicus. p ... | 1990 | 2171562 |
| a nonvirulent mutant of listeria monocytogenes does not move intracellularly but still induces polymerization of actin. | listeria monocytogenes has the capacity to penetrate and multiply within professional and nonprofessional phagocytic cells, such as the caco-2 human enterocytelike cell line. it was shown recently that shortly after listeriae have been phagocytosed, the phagosomal membrane is dissolved, probably by the action of the bacterial cytolysin listeriolysin o. the listeriae, which are then lying obviously free in the cytoplasm, become surrounded by a coat of actin filaments within a few hours. once form ... | 1990 | 2172164 |
| isolation of listeria monocytogenes small-plaque mutants defective for intracellular growth and cell-to-cell spread. | to dissect the regulatory and structural requirements for listeria monocytogenes intracellular growth and cell-to-cell spread, we designed a protocol based on transposon mutagenesis and the isolation of mutants which form small plaques in monolayers of mouse l2 cell fibroblasts. two different transposable elements were used to generate libraries of insertion mutants: tn916 and a derivative of tn917-lac, tn917-ltv3. ten classes of mutants were isolated and evaluated for growth and cell-to-cell sp ... | 1990 | 2172168 |