| the brucella suis homologue of the agrobacterium tumefaciens chromosomal virulence operon chve is essential for sugar utilization but not for survival in macrophages. | brucella strains possess an operon encoding type iv secretion machinery very similar to that coded by the agrobacterium tumefaciens virb operon. here we describe cloning of the brucella suis homologue of the chve-ggua-ggub operon of a. tumefaciens and characterize the sugar binding protein chve (78% identity), which in a. tumefaciens is involved in virulence gene expression. b. suis chve is upstream of the putative sugar transporter-encoding genes ggua and ggub, also present in a. tumefaciens, b ... | 2001 | 11514518 |
| construction and environmental release of a sinorhizobium meliloti strain genetically modified to be more competitive for alfalfa nodulation. | highly efficient nitrogen-fixing strains selected in the laboratory often fail to increase legume production in agricultural soils containing indigenous rhizobial populations because they cannot compete against these populations for nodule formation. we have previously demonstrated, with a sinorhizobium meliloti puta- mutant strain, that proline dehydrogenase activity is required for colonization and therefore for the nodulation efficiency and competitiveness of s. meliloti on alfalfa roots (j. ... | 2001 | 11525978 |
| signal peptide and propeptide optimization for heterologous protein secretion in lactococcus lactis. | lactic acid bacteria are food-grade microorganisms that are potentially good candidates for production of heterologous proteins of therapeutical or technological interest. we developed a model for heterologous protein secretion in lactococcus lactis using the staphylococcal nuclease (nuc). the effects on protein secretion of alterations in either (i) signal peptide or (ii) propeptide sequences were examined. (i) replacement of the native nuc signal peptide (sp(nuc)) by that of l. lactis protein ... | 2001 | 11526014 |
| interferon-gamma is crucial for surviving a brucella abortus infection in both resistant c57bl/6 and susceptible balb/c mice. | brucella abortus is an intracellular bacterial pathogen that causes chronic infections in humans and a number of agriculturally important species of animals. it has been shown that balb/c mice are more susceptible to infections with virulent strains of brucella abortus than c57bl/6 or c57bl/10 strains. in experiments described here, gene knock-out mice were utilized to elucidate some of the salient components of resistance. resistant c57bl/6 mice with gene deletions or disruptions in the interfe ... | 2001 | 11529943 |
| identification, characterization, and functional analysis of a gene encoding the ferric uptake regulation protein in bartonella species. | environmental iron concentrations coordinately regulate transcription of genes involved in iron acquisition and virulence via the ferric uptake regulation (fur) system. we identified and sequenced the fur gene and flanking regions of three bartonella species. the most notable difference between bartonella fur and other fur proteins was a substantially higher predicted isoelectric point. no promoter activity or fur autoregulation was detected using a gfp reporter gene fused to the 204 nucleotides ... | 2001 | 11544240 |
| ferrochelatase is present in brucella abortus and is critical for its intracellular survival and virulence. | brucella spp. are pathogenic bacteria that cause brucellosis, an animal disease which can also affect humans. although understanding the pathogenesis is important for the health of animals and humans, little is known about virulence factors associated with it. in order for chronic disease to be established, brucella spp. have developed the ability to survive inside phagocytes by evading cell defenses. it hides inside vacuoles, where it then replicates, indicating that it has an active metabolism ... | 2001 | 11553564 |
| induction of immune response in balb/c mice with a dna vaccine encoding bacterioferritin or p39 of brucella spp. | in this study, we evaluated the ability of dna vaccines encoding the bacterioferritin (bfr) or p39 proteins of brucella spp. to induce cellular and humoral immune responses and to protect balb/c mice against a challenge with b. abortus 544. we constructed eukaryotic expression vectors called pcibfr and pcip39, encoding bfr or p39 antigens, respectively, and we verified that these proteins were produced after transfection of cos-7 cells. pcibfr or pcip39 was injected intramuscularly three times, ... | 2001 | 11553569 |
| intracellular induction of the bartonella henselae virb operon by human endothelial cells. | one of the more recently identified bacterial exportation systems is the type iv secretion mechanism, which is characterized by a multiprotein complex that spans the inner and outer bacterial membranes and contains a pilin component. the most thoroughly studied type iv secretion system is encoded by the virb operon of agrobacterium tumefaciens. in bartonella henselae, 8 of the 10 virb operon genes share extensive homology and arrangement with the virb operon of a. tumefaciens. sequencing of the ... | 2001 | 11553594 |
| cloning, nucleotide sequence, and expression of the brucella melitensis sucb gene coding for an immunogenic dihydrolipoamide succinyltransferase homologous protein. | the brucella melitensis sucb gene encoding the dihydrolipoamide succinyltransferase (e2o) enzyme (previously identified as an immunogenic protein in infected sheep) was cloned and sequenced. the amino acid sequence predicted from the cloned gene revealed 88.8 and 51.2% identity to the dihydrolipoamide succinyltransferase sucb protein from brucella abortus and escherichia coli, respectively. sera from naturally infected sheep showed antibody reactivity against the recombinant sucb protein. | 2001 | 11553602 |
| mouse cytokine profiles associated with brucella abortus rb51 vaccination or b. abortus 2308 infection. | this study indicated that mice immunized with brucella abortus rb51 bacteria and subsequently challenged with b. abortus 2308 were protected from reinfection. after vaccination, both th1 and th2 cytokine patterns were observed. of those, the early production of gamma interferon seems to have the prominent role in inducing an immunologically based protection. | 2001 | 11553603 |
| attenuation of a brucella abortus mutant lacking a major 25 kda outer membrane protein in cattle. | to determine the virulence of a brucella abortus mutant, ba25, lacking a major 25 kd outer membrane protein (omp25) in cattle. | 2001 | 11560278 |
| [persistent properties of brucella abortus isolated from various sources]. | persistence factors in 70 b. abortus strains isolated from different sources were studied. depending on the source of the isolation of b. abortus, the spread of their antilysozyme, anticomplementary, antiintercidal activity was determined and intraspecific differences in the manifestation of these signs were established. the highest spread and manifestation of persistence factors was registered in b. abortus populations isolated from brucellosis patients and from cattle. | 2001 | 11569250 |
| diagnostic yield of a pcr assay in focal complications of brucellosis. | in order to evaluate the diagnostic yield of a pcr assay for patients with focal complications of brucellosis, we studied by pcr and by conventional microbiological techniques 34 nonblood samples from 32 patients with different focal forms of brucellosis. the samples from patients with brucellosis were paired to an equal number of control samples from the same locations of patients whose illnesses had different etiologies. thirty-three of the 34 nonblood samples (97%) from the brucellosis patien ... | 2001 | 11574607 |
| gtpases of the rho subfamily are required for brucella abortus internalization in nonprofessional phagocytes: direct activation of cdc42. | members of the genus brucella are intracellular alpha-proteobacteria responsible for brucellosis, a chronic disease of humans and animals. little is known about brucella virulence mechanisms, but the abilities of these bacteria to invade and to survive within cells are decisive factors for causing disease. transmission electron and fluorescence microscopy of infected nonprofessional phagocytic hela cells revealed minor membrane changes accompanied by discrete recruitment of f-actin at the site o ... | 2001 | 11579087 |
| seroconversion and abortion in cattle experimentally infected with brucella sp. isolated from a pacific harbor seal (phoca vitulina richardsi). | previously unrecognized brucella species have been isolated from a number of marine mammals, including harbor seals (phoca vitulina richardsi) in the puget sound area of the state of washington. because of the presence of dairy herds in proximity to the harbor seal populations, a study was conducted to determine the effects of the harbor seal brucella isolate in experimentally inoculated cattle. six pregnant cattle were exposed by intravenous injection (n = 3) or intraconjunctival inoculation (n ... | 2001 | 11580057 |
| use of detergent extracts of brucella abortus rb51 to detect serologic responses in rb51-vaccinated cattle. | serologic responses to the newly introduced rough brucella abortus vaccine strain rb51 have been determined in a dot-blot format using gamma-irradiated rb51 cells as the antigen. because gamma-irradiated cells are not easily prepared and the signal from cells was not always reliable, an alternative antigen was sought. detergent extracts of b. abortus rb51 were prepared using zwittergent 3-14, triton x-100, and sodium dodecyl sulfate (sds) and examined in a dot-blot format. zwittergent 3-14 extra ... | 2001 | 11580062 |
| genetic analysis of the sinorhizobium meliloti baca protein: differential effects of mutations on phenotypes. | sinorhizobium meliloti strains lacking baca function are impaired in symbiosis with alfalfa host plants and display altered sensitivities to a number of compounds relative to wild-type strains. with the goal of finding clues to the currently unknown biological function(s) of baca, we carried out a genetic analysis to determine which amino acids are critical for protein function and to attempt to ascertain whether the multiple phenotypes that result from a baca-null allele were the result of a co ... | 2001 | 11591690 |
| characterization of a brucella species 25-kilobase dna fragment deleted from brucella abortus reveals a large gene cluster related to the synthesis of a polysaccharide. | in the present study we completed the nucleotide sequence of a brucella melitensis 16m dna fragment deleted from b. abortus that accounts for 25,064 bp and show that the other brucella spp. contain the entire 25-kb dna fragment. two short direct repeats of four nucleotides, detected in the b. melitensis 16m dna flanking both sides of the fragment deleted from b. abortus, might have been involved in the deletion formation by a strand slippage mechanism during replication. in addition to omp31, co ... | 2001 | 11598046 |
| minor nucleotide substitutions in the omp31 gene of brucella ovis result in antigenic differences in the major outer membrane protein that it encodes compared to those of the other brucella species. | the gene coding for the major outer membrane protein omp31 was sequenced in five brucella species and their biovars. although the omp31 genes appeared to be highly conserved in the genus brucella, nine nucleotide substitutions were detected in the gene of brucella ovis compared to that of brucella melitensis. as shown by differential binding properties of monoclonal antibodies (mabs) to the two brucella species, these nucleotide substitutions result in different antigenic properties of omp31. th ... | 2001 | 11598077 |
| congeners of smap29 kill ovine pathogens and induce ultrastructural damage in bacterial cells. | smap29, an ovine cathelicidin, was systematically altered to create a family of 23 related peptides for mic and minimum bactericidal concentration determinations. smap28, smap29, and a derivative of smap29 called ovispirin were all antimicrobial. however, many congeners of smap29 and ovispirin were not as active as the parent molecules. with immunoelectron microscopy, smap29 was seen on membranes and within the cytoplasm of pseudomonas aeruginosa pao1. | 2001 | 11600395 |
| protection from experimental endotoxemia by a recombinant adeno-associated virus encoding interleukin 10. | interleukin 10 (il-10) is a homodimeric cytokine that shows considerable clinical promise. adeno-associated virus (aav) vectors appear increasingly useful for in vivo gene-transfer applications. | 2001 | 11601758 |
| validation of a commercially available monoclonal antibody-based competitive-inhibition enzyme-linked immunosorbent assay for detection of serum antibodies to neospora caninum in cattle. | a previously described monoclonal antibody (mab)-based competitive-inhibition enzyme-linked immunosorbent assay (celisa) was modified to optimize performance, and the assay was validated in various defined cattle populations for detection of serum antibody to neospora caninum, a major cause of bovine abortion. modifications to the celisa included capturing native n. caninum antigen with a parasite-specific mab (mab 5b6-25) and directly conjugating the competitor mab (mab 4a4-2), with both mabs b ... | 2001 | 11682497 |
| evaluation of two enzyme-linked immunosorbent assays for detecting salmonella enterica subsp. enterica serovar dublin antibodies in bulk milk. | two enzyme-linked immunosorbent assays (elisas) for the detecting salmonella enterica subsp. enterica serovar dublin antibodies in bulk milk were developed and evaluated for potential use in control programs. the elisas were based on either lipopolysacharide (lps elisa) or flagellar antigen (gp elisa). sensitivity was determined with 79 case herds with a wide range of clinical signs. specificity was determined with 125 dutch and 200 swedish control herds. the relation between antibodies in bulk ... | 2001 | 11687438 |
| mycobacterial di-o-acyl-trehalose inhibits mitogen- and antigen-induced proliferation of murine t cells in vitro. | 2,3-di-o-acyl-trehalose (dat) is a glycolipid located on the outer layer of the mycobacterium tuberculosis cell envelope. due to its noncovalent linkage to the mycobacterial peptidoglycan, dat could easily interact with host cells located in the focus of infection. the aim of the present work was to study the effects of dat on the proliferation of murine spleen cells. dat was purified from reference strains of m. tuberculosis, or m. fortuitum as a surrogate source of the compound, by various chr ... | 2001 | 11687444 |
| the plant oncogene rold encodes a functional ornithine cyclodeaminase. | the plant oncogene rold stimulates the reproductive phase transition in plants. we define here the function of its gene product. we show that the rold protein bears sequence homology with ornithine cyclodeaminase, an uncommon enzyme of specialized-niche eubacteria and archaea that catalyzes the unusual nad(+)-dependent conversion of ornithine to proline. to confirm the prediction of the bioinformatic analysis, the rold protein was expressed in escherichia coli and purified. an ornithine-dependen ... | 2001 | 11687622 |
| protective killed leptospira borgpetersenii vaccine induces potent th1 immunity comprising responses by cd4 and gammadelta t lymphocytes. | leptospira borgpetersenii serovar hardjo is the most common cause of bovine leptospirosis and also causes zoonotic infections of humans. a protective killed vaccine against serovar hardjo was shown to induce strong antigen-specific proliferative responses by peripheral blood mononuclear cells (pbmc) from vaccinated cattle by 2 months after the first dose of vaccine. this response was absent from nonvaccinated control cattle. the mean response peaked by 2 months after completion of the two-dose v ... | 2001 | 11705932 |
| identification, characterization, and variation in expression of two serologically distinct o-antigen epitopes in lipopolysaccharides of campylobacter fetus serotype a strains. | monoclonal antibodies (mabs) to the lipopolysaccharide (lps) o-antigens of campylobacter fetus serotype a and b strains were produced. eight mabs specific for serotype a lps were characterized on immunoblots of c. fetus serotype a lps. two immunoblot patterns were observed and were used to divide the eight mabs into two groups. mabs m1177 and m1194 were selected as representative of the two groups and were used in an enzyme-linked immunosorbent assay (elisa) to examine the lps o-antigen epitopes ... | 2001 | 11705938 |
| dna adenine methylase is essential for viability and plays a role in the pathogenesis of yersinia pseudotuberculosis and vibrio cholerae. | salmonella strains that lack or overproduce dna adenine methylase (dam) elicit a protective immune response to different salmonella species. to generate vaccines against other bacterial pathogens, the dam genes of yersinia pseudotuberculosis and vibrio cholerae were disrupted but found to be essential for viability. overproduction of dam significantly attenuated the virulence of these two pathogens, leading to, in yersinia, the ectopic secretion of virulence proteins (yersinia outer proteins) an ... | 2001 | 11705940 |
| brucella abortus genes identified following constitutive growth and macrophage infection. | the chronicity of brucella abortus infection in humans and animals depends on the organism's ability to escape host defenses by gaining entry and surviving inside the macrophage. although no human vaccine exists for brucella, vaccine development in other bacteria has been based on deletions of selective nutritional as well as regulatory systems. our goal is to develop a vaccine for brucella. to further this aim, we have used a green fluorescent protein (gfp) reporter system to identify constitut ... | 2001 | 11705955 |
| application of high-density array-based signature-tagged mutagenesis to discover novel yersinia virulence-associated genes. | yersinia pestis, the causative agent of plague, and the enteropathogen yersinia pseudotuberculosis have nearly identical nucleotide similarity yet cause markedly different diseases. to investigate this conundrum and to study yersinia pathogenicity, we developed a high-density oligonucleotide array-based modification of signature-tagged mutagenesis (stm). y. pseudotuberculosis ypiii mutants constructed with the tagged transposons were evaluated in the murine yersiniosis infection model. the dna t ... | 2001 | 11705963 |
| salmonella dna adenine methylase mutants elicit protective immune responses to homologous and heterologous serovars in chickens. | salmonella dna adenine methylase (dam) mutants that lack or overproduce dam are highly attenuated for virulence in mice and confer protection against murine typhoid fever. to determine whether vaccines based on dam are efficacious in poultry, a salmonella dam(-) vaccine was evaluated in the protection of chicken broilers against oral challenge with homologous and heterologous salmonella serovars. a salmonella enterica serovar typhimurium dam(-) vaccine strain was attenuated for virulence in day- ... | 2001 | 11705984 |
| comparison of the antibody response in adult cattle against different epitopes of brucella abortus lipopolysaccharide. | the comparison of serological responses in a sample of adult, vaccinated and held-infected bovines with brucella abortus is reported. indirect enzyme immunoassav (eia) titration curves and western blotting tests for smooth-type lipopolysaccharide (s-lps), rough-type lps (r-lps) and lipid a were performed. in the initial screening of sera, an overall prevalence of 20.5% was found, which corresponds to a country with a high incidence of brucellosis. end-point eia titres against lps antigens from v ... | 2001 | 11708681 |
| high levels of nitric oxide production decrease early but increase late survival of brucella abortus in macrophages. | nitric oxide (no), produced by the inos protein, is known as a defense mechanism against various pathogens and an apoptotic inducer of cells. apoptosis can also be a host protective mechanism against intracellular bacteria. the intracellular survival of brucella abortus in raw264.7 macrophages was examined under conditions of the apoptotic inducer, no. since b. abortus does not induce high output of no, escherichia coli lps and ifn-gamma, as potential therapeutic modalities, were added to increa ... | 2001 | 11710842 |
| hydrogen peroxide fluxes and compartmentalization inside growing escherichia coli. | escherichia coli generates about 14 microm hydrogen peroxide (h(2)o(2)) per s when it grows exponentially in glucose medium. the steady-state intracellular concentration of h(2)o(2) depends on the rates at which this h(2)o(2) is dissipated by scavenging enzymes and by efflux from the cell. the rates of h(2)o(2) degradation by the two major scavenging enzymes, alkyl hydroperoxide reductase and catalase, were quantified. in order to estimate the rate of efflux, the permeability coefficient of memb ... | 2001 | 11717277 |
| development of a brucella suis specific hybridisation probe and pcr which distinguishes b. suis from brucella abortus. | a genomic library was prepared from brucella suis dna (mboi digested) and cloned into the bamhi site of puc18. colony hybridisation using a probe prepared from purified b. suis dna labelled with alpha 32p was carried out to identify colonies of interest. about 20 colonies, which gave an intense signal upon hybridisation with whole b. suis genomic dna as a probe, were selected. because of the high degree of dna homology between b. suis and brucella abortus, a short probe was chosen as it would mo ... | 2002 | 11731177 |
| comparison of the efficacy of brucella abortus strain rb51 and brucella melitensis rev. 1 live vaccines against experimental infection with brucella melitensis in pregnant ewes. | to test the efficacy of rough brucella strain vaccines in sheep, a vaccine recently developed in cattle (brucella abortus strain rb51) was assessed in comparison with the conventional rev. 1 vaccine. forty-five ewes from twelve to fourteen months of age, from brucellosis-free flocks, were allotted to three groups of fifteen ewes each. group one was vaccinated by the conjunctival route with 1.73 x 10(8) colony forming units (cfu) of rev. 1 vaccine. group two was vaccinated subcutaneously with 11 ... | 2001 | 11732416 |
| development and field validation of an avidin-biotin enzyme-linked immunosorbent assay kit for bovine brucellosis. | the avidin-biotin enzyme-linked immunosorbent assay (a-b elisa), for use in surveillance for bovine brucellosis in india was developed and calibrated using the indirect brucellosis elisa kit of the international atomic energy agency (iaea) as a reference. the reagents used in the a-b elisa were as follows: the smooth lipopolysaccharide of brucella abortus strain 99 (antigen); biotinylated anti-bovine immunoglobulin g (detection antibody); avidin-horseradish peroxidase (conjugate); and o-phenylen ... | 2001 | 11732417 |
| relationship between the level of dietary vitamin e and the immune response of broiler chickens. | the relationship between the dietary level of vitamin e (ve) and the immune response of broilers was studied in three experiments. immunity was assessed as antibody production to infectious bronchitis virus (ibv), srbc, and brucella abortus (ba) antigens, mitogenic response to phytohemagglutinin a (pha) and concanavalin a (con a), cutaneous basophil hypersensitivity (cbh) to pha, and lipopolysaccharide induction of acute-phase proteins (app) and heterophilia. a range of ve (0, 10, 17.5, 25, 37.5 ... | 2001 | 11732676 |
| the atp-dependent lon protease of salmonella enterica serovar typhimurium regulates invasion and expression of genes carried on salmonella pathogenicity island 1. | an early step in the pathogenesis of salmonella enterica serovar typhimurium infection is bacterial penetration of the intestinal epithelium. penetration requires the expression of invasion genes found in salmonella pathogenicity island 1 (spi1). these genes are controlled in a complex manner by regulators in spi1, including hila and invf, and those outside spi1, such as two-component regulatory systems and small dna-binding proteins. we report here that the expression of invasion genes and the ... | 2002 | 11741864 |
| immune control of brucella abortus 2308 infections in balb/c mice. | balb/c mice infected with brucella abortus strain 2308 have 10-fold higher levels of bacteria during the plateau phase of infection (the time period when the number of colony-forming units in vivo remains consistent) than the more resistant c57bl/10 mice. this is due to a cessation of interferon-gamma (ifn-gamma) production that begins after the first week of infection and continues until the end of the plateau phase at least 6 weeks post infection. despite the lack of ifn-gamma production durin ... | 2001 | 11750226 |
| the genome sequence of the facultative intracellular pathogen brucella melitensis. | brucella melitensis is a facultative intracellular bacterial pathogen that causes abortion in goats and sheep and malta fever in humans. the genome of b. melitensis strain 16m was sequenced and found to contain 3,294,935 bp distributed over two circular chromosomes of 2,117,144 bp and 1,177,787 bp encoding 3,197 orfs. by using the bioinformatics suite ergo, 2,487 (78%) orfs were assigned functions. the origins of replication of the two chromosomes are similar to those of other alpha-proteobacter ... | 2002 | 11756688 |
| the genome sequence of the facultative intracellular pathogen brucella melitensis. | brucella melitensis is a facultative intracellular bacterial pathogen that causes abortion in goats and sheep and malta fever in humans. the genome of b. melitensis strain 16m was sequenced and found to contain 3,294,935 bp distributed over two circular chromosomes of 2,117,144 bp and 1,177,787 bp encoding 3,197 orfs. by using the bioinformatics suite ergo, 2,487 (78%) orfs were assigned functions. the origins of replication of the two chromosomes are similar to those of other alpha-proteobacter ... | 2002 | 11756688 |
| [immunoenzymatic test elisa in serodiagnosis of chronic brucellosis]. | though the acute brucella abortus infections among cattle and humans are not observed farm and veterinary service long standing workers have been still appearing with clinical symptoms resembling chronic brucellosis. the aim of the study was to evaluate usefulness of immunoenzymatic enzyme-linked immunosorbent assay (elisa) in serodiagnosis of chronic brucellosis. among 27 patients with chronic and in the past serologically confirmed brucellosis in seven (25.9%) the presence of specific igg anti ... | 2001 | 11761837 |
| effects of exogenous recombinant interleukin-12 on immune responses and protection against brucella abortus in a murine model. | this study determined if murine interleukin-12 (il-12) would influence immunity in mice vaccinated with live or killed brucella abortus strain rb51 (srb51). mice received live or gamma-irradiated srb51 bacteria alone, or with il-12 (0.5 or 1.0 microg, 2x or 3x), whereas other mice received saline or il-12 alone. post-vaccination antibody responses to live or killed srb51 and clearance of live srb51 from splenic tissue were not influenced by il-12 treatments. mice were challenged at 12 weeks with ... | 2001 | 11768128 |
| poor perinatal outcome associated with maternal brucella abortus infection. | reports suggest that perinatal infection with brucella abortus does not cause poor obstetric outcomes, because of protective mechanisms in the human, not seen in animal species. | 1997 | 11770592 |
| candidate gene promoter polymorphisms and antibody response kinetics in chickens: interferon-gamma, interleukin-2, and immunoglobulin light chain. | an f2 population was produced from mating g0 highly inbred (>99%) males of two mhc-congenic fayoumi lines with g-b1 leghorn hens. the f2 population was essentially a full-sibship with the f1 sire line reflecting mhc effect. adult f2 hens (n = 158) were injected twice with srbc and whole fixed brucella abortus (ba). agglutinating antibody titer at 7 d after primary immunization and mean titer of the final three samples (days 18, 32, and 63 after the second immunization) were used as parameters fo ... | 2001 | 11771881 |
| dendritic cells pulsed with intact streptococcus pneumoniae elicit both protein- and polysaccharide-specific immunoglobulin isotype responses in vivo through distinct mechanisms. | immature bone marrow-derived myeloid dendritic cells (bmdcs) are induced to undergo phenotypic maturation and secretion of tumor necrosis factor (tnf)-alpha, interleukin (il)-6, il-12, and il-10 when pulsed in vitro with intact streptococcus pneumoniae. after transfer to naive mice, pulsed bmdcs induce immunoglobulin (ig) isotype responses specific for both protein and polysaccharide pneumococcal antigens, having in common the requirement for viable bmdcs, t cells, and b7-dependent costimulation ... | 2002 | 11781360 |
| induction of a th1-type of immune response but not protective immunity by intramuscular dna immunisation with brucella abortus groel heat-shock gene. | the immunogenicity and protective efficacy of a dna vaccine encoding the groel heat-shock gene from brucella abortus was tested in balb/c mice immunised by intramuscular (i.m.) needle injection or epidermally by gene gun. the brucella groel gene was amplified by pcr and cloned into two different mammalian expression vectors pcmv-link and pcmv-tpa. the d17 cell line was transfected with both constructs and groel transcripts were detected by northern blot. to determine the level of protein synthes ... | 2002 | 11803949 |
| recombinant adeno-associated virus serotype 2 vectors mediate stable interleukin 10 secretion from salivary glands into the bloodstream. | we have constructed a recombinant adeno-associated virus serotype 2 vector encoding human interleukin 10 (raavhil10). il-10 is a potent antiinflammatory/immune cytokine, which has received growing attention for its therapeutic potential. human il-10 (hil-10) production was virus dose dependent after in vitro infection of hsg cells, a human submandibular gland cell line. the vector-derived hil-10 produced was biologically active, as the medium from raavhil10-infected hsg cells caused a dose-depen ... | 2002 | 11812284 |
| the genetic organization and evolution of the broad host range mercury resistance plasmid psb102 isolated from a microbial population residing in the rhizosphere of alfalfa. | employing the biparental exogenous plasmid isolation method, conjugative plasmids conferring mercury resistance were isolated from the microbial community of the rhizosphere of field grown alfalfa plants. five different plasmids were identified, designated psb101-psb105. one of the plasmids, psb102, displayed broad host range (bhr) properties for plasmid replication and transfer unrelated to the known incompatibility (inc) groups of bhr plasmids incp-1, incw, incn and inca/c. nucleotide sequence ... | 2001 | 11812851 |
| mucosal immunity in mice immunized with hiv-1 peptide conjugated to brucella abortus. | we have previously shown that a v3-loop peptide from hiv-1 envelope conjugated to heat-inactivated brucella abortus (ba) (v3-ba) is capable of inducing antibodies that neutralize hiv-1 and cytotoxic t cells (ctl) that kill hiv-1-infected targets, even in mice that lack cd4(+) t cells. in this paper we show that intranasal (i.n.) immunization elicits neutralizing antibodies and ifngamma-secreting t cells at mucosal surfaces. this approach may protect individuals from hiv-1 infection and reduce tr ... | 2002 | 11818165 |
| production and targeting of the brucella abortus antigen l7/l12 in lactococcus lactis: a first step towards food-grade live vaccines against brucellosis. | brucella abortus is a facultative intracellular gram-negative bacterial pathogen that infects humans and animals by entry mainly through the digestive tract. b. abortus causes abortion in pregnant cattle and undulant fever in humans. the immunogenic b. abortus ribosomal protein l7/l12 is a promising candidate antigen for the development of oral live vaccines against brucellosis, using food-grade lactic acid bacteria (lab) as a carrier. the l7/l12 gene was expressed in lactococcus lactis, the mod ... | 2002 | 11823235 |
| production of human papillomavirus type 16 e7 protein in lactococcus lactis. | the e7 protein of human papillomavirus type 16 was produced in lactococcus lactis. secretion allowed higher production yields than cytoplasmic production. in stationary phase, amounts of cytoplasmic e7 were reduced, while amounts of secreted e7 increased, suggesting a phase-dependent intracellular proteolysis. fusion of e7 to the staphylococcal nuclease, a stable protein, resulted in a highly stable cytoplasmic protein. this work provides new candidates for development of viral screening systems ... | 2002 | 11823236 |
| the brucella suis virb operon is induced intracellularly in macrophages. | a type iv secretion system similar to the virb system of the phytopathogen agrobacterium tumefaciens is essential for the intracellular survival and multiplication of the mammalian pathogen brucella. reverse transcriptase-pcr showed that the 12 genes encoding the brucella suis virb system form an operon. semiquantitative measurements of virb mrna levels by slot blotting showed that transcription of the virb operon, but not the flanking genes, is regulated by environmental factors in vitro. flow ... | 2002 | 11830669 |
| brucella abortus strain 2308 produces brucebactin, a highly efficient catecholic siderophore. | brucella abortus is known to produce 2,3-dihydroxybenzoate (2,3-dhba) and to use this catechol as a siderophore to grow under iron-limited conditions. in this study a mutant (bam41) is described that is deficient in siderophore production by insertion of tn5 in the virulent b. abortus strain 2308. this mutant was unable to grow on iron-deprived medium and its growth could not be restored by addition of 2,3-dhba. production of catecholic compounds by both the brucella mutant and parental strains ... | 2002 | 11832499 |
| brucella abortus strain rb51 vaccination in elk. i. efficacy of reduced dosage. | bovine brucellosis is a serious zoonotic disease affecting some populations of rocky mountain elk (cervus elaphus nelsoni) and bison (bison bison) in the greater yellowstone area, usa. the fear that elk and/or bison may spread brucella abortus to livestock has prompted efforts to reduce or eliminate the disease in wildlife. brucella abortus strain rb51 (rb51) vaccine has recently been approved for use in cattle. unlike strain 19 vaccine, rb51 does not cause false positive reactions on standard b ... | 2002 | 11838212 |
| brucella abortus strain rb51 vaccination in elk. ii. failure of high dosage to prevent abortion. | brucella abortus strain rb51 is used as a vaccine because it induces antibodies that do not react on standard serologic tests for brucellosis allowing differentiation between vaccination and infection. strain rb51 was evaluated in captive elk (cervus elaphus) to determine if vaccination protected against abortion following experimental challenge. thirty elk were vaccinated intramuscularly with 1.0 x 10(10) colony-forming units (cfu) of strain rb51 in march 1998. fourteen of these were given a bo ... | 2002 | 11838225 |
| study of interleukin-10 and interleukin-12 productions in response to lipopolysaccharides extracted from two different brucella strains. | the aim of the present study is to investigate the cytokines induction by smooth lipopolysaccharides (s-lps) extracted from brucella melitensis (rev1 vaccine strain) and brucella abortus (a field isolate). these lipopolysaccharides were used to induce inflammatory cytokines production in peripheral blood cell culture of healthy individuals. secretion of il-10 and il-12 (p70) were measured by means of specific elisa. in addition, intracellular expression of il-12 was assessed in cd14+ cells by fl ... | 2002 | 11848132 |
| identification of major outer surface proteins of streptococcus agalactiae. | to identify the major outer surface proteins of streptococcus agalactiae (group b streptococcus), a proteomic analysis was undertaken. an extract of the outer surface proteins was separated by two-dimensional electrophoresis. the visualized spots were identified through a combination of peptide sequencing and reverse genetic methodologies. of the 30 major spots identified as s. agalactiae specific, 27 have been identified. six of these proteins, previously unidentified in s. agalactiae, were seq ... | 2002 | 11854208 |
| survival of tropheryma whipplei, the agent of whipple's disease, requires phagosome acidification. | tropheryma whipplei was established as the agent of whipple's disease in 2000, but the mechanisms by which it survives within host cells are still unknown. we show here that t. whipplei survives within hela cells by controlling the biogenesis of its phagosome. indeed, t. whipplei colocalized with lysosome-associated membrane protein 1, a membrane marker of late endosomal and lysosomal compartments, but not with cathepsin d, a lysosomal hydrolase. this defect in phagosome maturation is specific t ... | 2002 | 11854238 |
| induction of dnak through its native heat shock promoter is necessary for intramacrophagic replication of brucella suis. | the heat shock protein dnak is essential for intramacrophagic replication of brucella suis. the replacement of the stress-inducible, native dnak promoter of b. suis by the promoter of the constitutively expressed bla gene resulted in temperature-independent synthesis of dnak. in contrast to a dnak null mutant, this strain grew at 37 degrees c, with a thermal cutoff at 39 degrees c. however, the constitutive dnak mutant, which showed high sensitivity to h(2)o(2)-mediated stress, failed to multipl ... | 2002 | 11854256 |
| role of cholesterol and the ganglioside gm(1) in entry and short-term survival of brucella suis in murine macrophages. | brucella species are gram-negative, facultative intracellular bacteria that infect humans and animals. these organisms can survive and replicate within a membrane-bound compartment inside professional and nonprofessional phagocytic cells. inhibition of phagosome-lysosome fusion has been proposed as a mechanism for intracellular survival in both types of cells. we have previously shown that the maturation inhibition of the brucella-containing phagosome appears to be restricted at the phagosomal m ... | 2002 | 11854258 |
| interferon alpha/beta and interleukin 12 responses to viral infections: pathways regulating dendritic cell cytokine expression in vivo. | interferon (ifn)-alpha/beta and interleukin (il)-12 are cytokines critical in defense against viruses, but their cellular sources and mechanisms of regulation for in vivo expression remain poorly characterized. the studies presented here identified a novel subset of dendritic cells (dcs) as major producers of the cytokines during murine cytomegalovirus (mcmv) but not lymphocytic choriomeningitis virus (lcmv) infections. these dcs differed from those activated by toxoplasma antigen but were relat ... | 2002 | 11854364 |
| bacterial interactions with the autophagic pathway. | bacteria have evolved a variety of mechanisms to invade eukaryotic cells and survive intracellularly. once inside, bacterial pathogens often modulate their phagosome to establish an intracellular niche for survival and replication. a subset of intracellular pathogens, including brucella abortus, legionella pneumophila and porphyromonas gingivalis, are diverted from the endosomal pathway to the auto-phagic pathway. once within the autophagosome, each in some way presumably modifies this compartme ... | 2002 | 11856168 |
| susceptibility of ifn regulatory factor-1 and ifn consensus sequence binding protein-deficient mice to brucellosis. | ifn-gamma is a key cytokine controlling brucella infection, and the diverse functions of this cytokine are mediated by ifn regulatory factors (irfs) such as irf-1, irf-2, and ifn consensus sequence binding protein (icsbp). however, the roles of these three irfs in brucella infection have not been investigated. the infection of each irf-deficient mouse strain provides an opportunity to determine not only the significance of each irf molecule but also the crucial immune components necessary for ho ... | 2002 | 11859135 |
| immunological characterization of a gammadelta t-cell stimulatory ligand on autologous monocytes. | bovine gammadelta t cells are stimulated to proliferate by autologous monocytes. this is referred to as the autologous mixed leucocyte reaction (amlr). it has been shown previously that the stimulatory component is constitutively expressed on the monocyte plasma membrane and is a protein or has a protein moiety. here we showed that gammadelta t-cell responses to the monocytes requires interaction with the t-cell receptor because fab1 fragments of a monoclonal antibody (mab) that reacts with the ... | 2002 | 11872093 |
| diagnostic usefulness of antibodies against ribosome recycling factor from brucella melitensis in human or canine brucellosis. | the diagnostic usefulness of an enzyme-linked immunosorbent assay (elisa) using a purified recombinant ribosome recycling factor from brucella melitensis (cp24 antigen) was tested in human and canine infections caused by smooth and rough brucella species, respectively. anti-cp24 antibodies were detected in 9 (43%) of 21 consecutive cases of canine brucellosis and in 8 (53%) of 15 dogs followed for 60 days after the diagnosis of acute brucellosis. among eight patients with acute brucellosis, anti ... | 2002 | 11874879 |
| effect of exogenous interleukin-18 (il-18) and il-12 in the course of brucella abortus 2308 infection in mice. | in this study we demonstrated that combined inoculation of interleukin-12 (il-12) and il-18 reduced the number of bacteria in the spleens of mice infected with brucella abortus 2308 and that the effect of the treatment was mediated by an increased capability of spleen cells to produce gamma interferon at the early phase of infection. | 2002 | 11874900 |
| expression of a crown gall biological control phenotype in an avirulent strain of agrobacterium vitis by addition of the trifolitoxin production and resistance genes. | agrobacterium vitis is a causal agent of crown-gall disease. trifolitoxin (tfx) is a peptide antibiotic active only against members of a specific group of alpha-proteobacteria that includes agrobacterium and its close relatives. the ability of tfx production by an avirulent strain of agrobacterium to reduce crown gall disease is examined here. | 2002 | 11882255 |
| type ivb secretion by intracellular pathogens. | a growing number of pathogens are being found to possess specialized secretion systems which they use in various ways to subvert host defenses. one class, called type iv, are defined as having homology to the conjugal transfer systems of naturally occurring plasmids. it has been proposed that pathogens with type iv secretion systems have acquired and adapted the conjugal transfer systems of plasmids and now use them to export toxins. several well-characterized intracellular pathogens, including ... | 2002 | 11886588 |
| yersinia enterocolitica as a vehicle for a naked dna vaccine encoding brucella abortus bacterioferritin or p39 antigen. | brucella is a facultative intracellular parasite that causes brucellosis in animals and humans. the protective immune response against brucella involves both humoral and cell-mediated immunity. in previous studies, we demonstrated that the t-dominant brucella antigens bacterioferritin (bfr) and p39 administered either as cpg adjuvant recombinant proteins or as naked-dna plasmids induced a specific th1-biased immune response in mice. in order to improve the protection conferred by the bfr and p39 ... | 2002 | 11895955 |
| characterization and transcriptional analysis of gene clusters for a type iv secretion machinery in human granulocytic and monocytic ehrlichiosis agents. | anaplasma (ehrlichia) phagocytophila and ehrlichia chaffeensis, the etiologic agents of granulocytic and monocytic ehrlichioses, respectively, are obligatory intracellular bacteria that cause febrile systemic illness in humans. we identified and characterized clusters of genes for a type iv secretion machinery in these two bacteria, and analyzed their gene expression in cell culture and mammalian hosts. eight virb and vird genes were found in each bacterial genome, and all of the genes were tran ... | 2002 | 11895979 |
| chronic intracellular infection of alfalfa nodules by sinorhizobium meliloti requires correct lipopolysaccharide core. | our analyses of lipopolysaccharide mutants of sinorhizobium meliloti offer insights into how this bacterium establishes the chronic intracellular infection of plant cells that is necessary for its nitrogen-fixing symbiosis with alfalfa. derivatives of s. meliloti strain rm1021 carrying an lpsb mutation are capable of colonizing curled root hairs and forming infection threads in alfalfa in a manner similar to a wild-type strain. however, developmental abnormalities occur in the bacterium and the ... | 2002 | 11904442 |
| peptides with indirect in vivo activity against an intracellular pathogen: selective lysis of infected macrophages. | a collection of natural peptides, simplified analogs of natural peptides, de novo amphipathic peptides and de novo amphipathic peptides composed of 50-80% alpha,alpha-dialkylated glycines (alpha,alpha-dags) were synthesized on solid-phase resin as the c-terminus amides using n-alpha-fluorenylmethyloxycarbonyl protection. the synthesis of the peptides rich in alpha,alpha-dags used acid fluoride coupling methods. the peptides show antimicrobial activity against escherichia coli and staphylococcus ... | 2002 | 11906603 |
| brucella abortus vaccine strain rb51 produces low levels of m-like o-antigen. | brucella abortus rb51 is a rough (r) stable vaccine strain used in cattle and is believed to be devoid of o-side chain. we analyzed by use of a panel of monoclonal antibodies (mabs) directed against seven previously defined o-polysaccharide (o-ps) epitopes the o-chain expression in strain rb51. two mabs specific for the c/y (a=m) and c (m>a) epitopes showed low bindings in elisa to strain rb51. o-chain expression was further confirmed by western blot after sds-page of strain rb51. in particular, ... | 2002 | 11906770 |
| pathogenic and immunosuppressive effects of avian pneumovirus in turkeys. | avian pneumovirus (apv) causes a respiratory disease in turkeys. the virus has been associated with morbidity and mortality due to secondary infections. our objective was to determine if apv caused immunosuppression in the t-cell or b-cell compartments and to study the pathogenesis of the disease in apv maternal antibody-lacking 2-wk-old commercial turkeys. apv was administered by the eyedrop/intranasal route. observations were made for gross lesions, viral genome, and t-cell mitogenesis and cyt ... | 2002 | 11922327 |
| the effect of brucella abortus on hydrogen peroxide and nitric oxide production by bovine polymorphonuclear cells. | the effect of brucella on the generation of microbicidal reactive oxygen and nitrogen metabolites by bovine peripheral polymorphonuclear cells (pmns) was investigated. the pmns were recovered from the peripheral blood of control calves and experimental calves previously vaccinated against brucellosis. significantly larger quantities of no and h2o2 were generated by pmns from control and experimental calves following activation by heat-killed whole cells or outer membrane protein of brucella abor ... | 2002 | 11922486 |
| the dutch brucella abortus monitoring programme for cattle: the impact of false-positive serological reactions and comparison of serological tests. | the dutch national brucella abortus eradication programme for cattle started in 1959. sporadic cases occurred yearly until 1995; the last infected herd was culled in 1996. in august 1999 the netherlands was declared officially free of bovine brucellosis by the european union. before 1999, the programme to monitor the official brucella-free status of bovine herds was primarily based on periodical testing of dairy herds with the milk ring test (mrt) and serological testing of all animals older tha ... | 2002 | 11924560 |
| plasticity of a transcriptional regulation network among alpha-proteobacteria is supported by the identification of ctra targets in brucella abortus. | ctra is a master response regulator found in many alpha-proteobacteria. in caulobacter crescentus and sinorhizobium meliloti, this regulator is essential for viability and is transcriptionally autoregulated. in c. crescentus, it is required for the regulation of multiple cell cycle events, such as dna methylation, dna replication, flagella and pili biogenesis and septation. here, we report the characterization of the ctra gene homologue in the alpha2-proteobacteria brucella abortus, a facultativ ... | 2002 | 11929544 |
| the genome of m. acetivorans reveals extensive metabolic and physiological diversity. | methanogenesis, the biological production of methane, plays a pivotal role in the global carbon cycle and contributes significantly to global warming. the majority of methane in nature is derived from acetate. here we report the complete genome sequence of an acetate-utilizing methanogen, methanosarcina acetivorans c2a. methanosarcineae are the most metabolically diverse methanogens, thrive in a broad range of environments, and are unique among the archaea in forming complex multicellular struct ... | 2002 | 11932238 |
| a dna vaccine encoding lumazine synthase from brucella abortus induces protective immunity in balb/c mice. | this study was conducted to evaluate the immunogenicity of the brucella abortus lumazine synthase (bls) gene cloned into the pcdna3 plasmid, which is driven by the cytomegalovirus promoter. injection of plasmid dna carrying the bls gene (pcdna-bls) into balb/c mice elicited both humoral and cellular immune responses. antibodies to the encoded bls included immunoglobulin g1 (igg1) igg2a, igg2b, igg3, and igm isotypes. animals injected with pcdna-bls exhibited a dominance of igg2a over igg1. in ad ... | 2002 | 11953389 |
| recombinant ochrobactrum anthropi expressing brucella abortus cu,zn superoxide dismutase protects mice against b. abortus infection only after switching of immune responses to th1 type. | the members of the genus brucella are gram-negative, facultatively intracellular bacterial pathogens that cause brucellosis in many animal species and humans. although live, attenuated vaccines are available to protect several animal species from the disease, there is no safe and effective vaccine for human use. here we report that a bacterium that is closely related to brucella species, ochrobactrum anthropi, can be used as a vaccine vector for the delivery of brucella antigens to mice, leading ... | 2002 | 11953393 |
| evidence for lateral transfer to brucellae: characterization of a locus with a tn-like element (tn2020). | a genomic locus was discovered within brucella abortus that contains a novel transposon-like element designated tn2020. tn2020 is bounded by a copy of an insertion sequence designated is2020 and a truncated imperfect copy of is2020 (tis2020a). the truncated copy is immediately adjacent to a second copy of is2020. these data are consistent with the locus having evolved by a complex rearrangement following the transposition of a second copy of tn2020. analysis of the organization, orientation, and ... | 2002 | 11955619 |
| high-density microarray of small-subunit ribosomal dna probes. | ribosomal dna sequence analysis, originally conceived as a way to provide a universal phylogeny for life forms, has proven useful in many areas of biological research. some of the most promising applications of this approach are presently limited by the rate at which sequences can be analyzed. as a step toward overcoming this limitation, we have investigated the use of photolithography chip technology to perform sequence analyses on amplified small-subunit rrna genes. the genechip (affymetrix co ... | 2002 | 11976131 |
| the global phylogeny of glycolytic enzymes. | genes encoding the glycolytic enzymes of the facultative endocellular parasite bartonella henselae have been analyzed phylogenetically within a very large cohort of homologues from bacteria and eukaryotes. we focus on this relative of rickettsia prowazekii along with homologues from other alpha-proteobacteria to determine whether there have been systematic transfers of glycolytic genes from the presumed alpha-proteobacterial ancestor of the mitochondrion to the nucleus of the early eukaryote. th ... | 2002 | 11983902 |
| an essential virulence protein of brucella abortus, virb4, requires an intact nucleoside-triphosphate-binding domain. | brucella abortus is a facultative intracellular bacterium capable of surviving inside macrophages. the virb complex, which is highly similar to conjugative dna transfer apparatuses, is required for intracellular replication. a conserved ntp-binding domain in virb4 suggests that one or both proteins couple energy by ntp hydrolysis to transport of putative effector molecule(s). here it is shown that a mutant strain of b. abortus that contains an in-frame deletion in virb4 is unable to replicate in ... | 2002 | 11988518 |
| inhibitors of cop-mediated transport and cholera toxin action inhibit simian virus 40 infection. | simian virus 40 (sv40) is a nonenveloped virus that has been shown to pass from surface caveolae to the endoplasmic reticulum in an apparently novel infectious entry pathway. we now show that the initial entry step is blocked by brefeldin a and by incubation at 20 degrees c. subsequent to the entry step, the virus reaches a domain of the rough endoplasmic reticulum by an unknown pathway. this intracellular trafficking pathway is also brefeldin a sensitive. infection is strongly inhibited by expr ... | 2002 | 12006667 |
| mapping and sequencing of the canine nramp1 gene and identification of mutations in leishmaniasis-susceptible dogs. | the nramp1 gene (slc11a1) encodes an ion transporter protein involved in the control of intraphagosomal replication of parasites and in macrophage activation. it has been described in mice as the determinant of natural resistance or susceptibility to infection with antigenically unrelated pathogens, including leishmania. our aims were to sequence and map the canine slc11a1 gene and to identify mutations that may be associated with resistance or susceptibility to leishmania infection. the canine ... | 2002 | 12010961 |
| identification of a quorum-sensing signal molecule in the facultative intracellular pathogen brucella melitensis. | brucella melitensis is a gram-negative alpha2-proteobacterium responsible for abortion in goats and for malta fever in humans. this facultative intracellular pathogen invades and survives within both professional and nonprofessional phagocytes. a dichloromethane extract of spent culture supernatant from b. melitensis induces bioluminescence in an escherichia coli acyl-homoserine lactone (acyl-hsl) biosensor strain based upon the activity of the lasr protein of pseudomonas aeruginosa. hplc fracti ... | 2002 | 12010991 |
| production of antibodies to sheep red blood cells and brucella abortus in mongolian gerbils (meriones unguiculatus). | the levels of total and 2-mercaptoethanol (2-me)-resistant antibodies in male mongolian gerbils (meriones unguiculatus) to sheep red blood cells (srbc) were higher than those in male c57bl/6 mice after the first and second immunizations. on the other hand, the total antibody level to brucella abortus (ba) in gerbils was comparable to that in mice, whereas 2-me-resistant antibody titers were lower after the first and second immunizations than in mice. after injection of 8 x 10(4) srbc, male gerbi ... | 2002 | 12012725 |
| expression cloning and characterization of the c28 acyltransferase of lipid a biosynthesis in rhizobium leguminosarum. | an unusual feature of lipid a from plant endosymbionts of the rhizobiaceae family is the presence of a 27-hydroxyoctacosanoic acid (c28) moiety. an enzyme that incorporates this acyl chain is present in extracts of rhizobium leguminosarum, rhizobium etli, and sinorhizobium meliloti but not escherichia coli. the enzyme transfers 27-hydroxyoctacosanate from a specialized acyl carrier protein (acpxl) to the precursor kdo2 ((3-deoxy-d-manno-octulosonic acid)2)-lipid iv(a). we now report the identifi ... | 2002 | 12019272 |
| analysis of mitogen-stimulated lymphocyte subset proliferation and nitric oxide production by peripheral blood mononuclear cells of captive elk (cervus elaphus). | elk (cervus claphus) are reservoirs for brucella abortus, mycobacterium bovis, and mycobacterium avium subsp. paratuberculosis, each a serious pathogen of domestic livestock. an understanding of the basic immune responsiveness of elk would aid efforts to develop methods to diagnose and prevent these diseases of elk. peripheral blood mononuclear cells (pbmc) isolated from captive elk were examined for phenotype, lymphocyte subset proliferative capacity, and ability to produce nitric oxide (no) up ... | 2002 | 12038134 |
| controlled production of stable heterologous proteins in lactococcus lactis. | the use of lactococcus lactis (the most extensively characterized lactic acid bacterium) as a delivery organism for heterologous proteins is, in some cases, limited by low production levels and poor-quality products due to surface proteolysis. in this study, we combined in one l. lactis strain use of the nisin-inducible promoter p(nisa) and inactivation of the extracellular housekeeping protease htra. the ability of the mutant strain, designated htra-nz9000, to produce high levels of stable prot ... | 2002 | 12039780 |
| protection of mice against brucellosis by intranasal immunization with brucella melitensis lipopolysaccharide as a noncovalent complex with neisseria meningitidis group b outer membrane protein. | intranasal immunization of mice with purified brucella melitensis lipopolysaccharide (lps) as a noncovalent complex with neisseria meningitidis group b outer membrane protein (gbomp) elicited a high-titer anti-lps systemic antibody response and a significant mucosal antibody response. the anti-lps immunoglobulin g (igg) antibody was predominantly of the igg1 subtype, although there was some response of the igg2a, igg2b, and igg3 subtypes. the antibody titer remained high for 16 weeks postimmuniz ... | 2002 | 12065469 |
| h(2)o(2), which causes macrophage-related stress, triggers induction of expression of virulence-associated plasmid determinants in rhodococcus equi. | the response of the intracellular pathogen rhodococcus equi to h(2)o(2) treatment, a situation potentially encountered after the oxidative burst of alveolar macrophages, was analyzed. compared to other bacteria, including deinococcus radiodurans, r. equi showed exceptionally high resistance to this stress. a proteomic approach showed that four polypeptides present in the wild-type strain (85f) are missing in the plasmid-cured strain 85f(p-), and by using a dna macroarray, we identified two plasm ... | 2002 | 12065520 |
| brucella abortus siderophore 2,3-dihydroxybenzoic acid (dhba) facilitates intracellular survival of the bacteria. | siderophores are low molecular weight molecules that allow bacteria to acquire iron from host cell proteins. 2,3-dihydroxybenzoic acid (dhba) is the only known siderophore produced by the intracellular pathogen brucella abortus. here its role in virulence was assessed by evaluating the ability of a mutant with a disruption of the entc gene to survive and replicate in vitro in murine and bovine cells and in vivo in resistant and susceptible murine hosts. it was hypothesized that dhba is vital for ... | 2002 | 12071680 |
| brucella abortus inta2, a novel strain 19 (delta)bp26::luc (delta)bmp18 double mutant lacking drug resistance markers. | brucella abortus inta2, a novel mutant strain, was constructed by inactivation of two b. abortus s19 genes: bp26 and bmp18, with the objective of obtaining a mutant strain that could be compatible with a diagnostic test and have less residual virulence than strain 19. the double mutant was constructed by replacing a large section of the bp26 coding region with the luciferase (luc) coding gene, resulting in mutant strain b. abortus m1luc, followed by partial deletion of bmp18 coding sequence. bot ... | 2002 | 12079742 |
| validation of an indirect enzyme-linked immunosorbent assay for the detection of antibody against brucella abortus in cattle sera using an automated elisa workstation. | an automated indirect enzyme-linked immunosorbent assay (i-elisa) for the serological diagnosis of bovine brucellosis was developed and validated in-house. a total of 4,803 cattle sera from south africa (n = 3,643), canada (n = 652), germany (n = 240), france (n = 73) and the usa (n = 195) was used. the south african panel of sera represented 834 sera known to be positive by the rose bengal test (rbt), serum agglutination test (sat) and complement fixation test (cft), 2709 sera that were negativ ... | 2002 | 12092779 |
| time-space clustering of human brucellosis, california, 1973-1992. | infection with brucella spp. continues to pose a human health risk in california despite great strides in eradicating the disease from domestic animals. clustering of human cases in time and space has important public health implications for understanding risk factors and sources of infection. temporal-spatial clustering of human brucellosis in california for the 20-year period 1973-1992 was evaluated by the ederer-myers-mantel, moran's i, and population-adjusted moran's i procedures. cases were ... | 2002 | 12095433 |
| legionella and legionnaires' disease: 25 years of investigation. | there is still a low level of clinical awareness regarding legionnaires' disease 25 years after it was first detected. the causative agents, legionellae, are freshwater bacteria with a fascinating ecology. these bacteria are intracellular pathogens of freshwater protozoa and utilize a similar mechanism to infect human phagocytic cells. there have been major advances in delineating the pathogenesis of legionellae through the identification of genes which allow the organism to bypass the endocytic ... | 2002 | 12097254 |