| on the presence and organization of open reading frames of the nonmotile pathogen brucella abortus similar to class ii, iii, and iv flagellar genes and to lcrd virulence superfamily. | brucellae are pathogenic, nonmotile bacteria that are facultative intracellular parasites. little is known about the genetics of these bacteria. open reading frames from brucella abortus with similarity to the flagellin, m-ring, and hook of related bacteria were discovered. the open reading frames encode proteins of three of the four flagellum gene classes, namely ii, iii, and iv. a homolog of the lcrd virulence superfamily was also found. this superfamily is involved in type iii protein secreti ... | 1998 | 11013709 |
| fluorescence polarization immunoassay: detection of antibody to brucella abortus. | fluorescence polarization immunoassay (fpa) is a homogeneous immunoassay useful for rapid and accurate detection of antibody or antigen. the principle of the assay is that a fluorescent dye (attached to an antigen or an antibody fragment) can be excited by plane-polarized light at the appropriate wavelength. as a rule, a small molecule rotates faster when in solution than a larger molecule. the rotation rate may be assessed by measuring light intensity in the vertical and horizontal planes. gene ... | 2000 | 11020320 |
| responses of adult cattle to vaccination with a reduced dose of brucella abortus strain rb51. | the efficacy of a reduced dosage of brucella abortus strain rb51 (srb51) was evaluated in adult cattle. hereford heifers were vaccinated with saline, or three srb51 dosing regimens (3 x 10(9) colony forming units (cfu) once, 1 x 10(9) cfu once, or 1 x 10(9) cfu twice). cattle vaccinated with 3 x 10(9) cfu of srb51 had greater (p < 0.05) antibody responses than non-vaccinates, and greater lymphocyte proliferative responses to srb51 than all other treatments. four of six non-vaccinated heifers abo ... | 2000 | 11020364 |
| single-shot plasmid dna intrasplenic immunization for the production of monoclonal antibodies. persistent expression of dna. | monoclonal antibodies (mc. abs.) were generated against a 18-kda protein from brucella abortus 48 h and 25 days after a single intrasplenic injection of a dna plasmid containing the expression vector for the protein. hybridomas were also obtained from spleens injected 3, 5, and 10 days before fusion. somatic cell fusion of spleen cells from mice, injected with the plasmid dna, in saline, with the ns-0 myeloma cell line resulted in mc. abs of the igg and igm isotypes. igg antibodies were of the i ... | 2000 | 11033013 |
| brucella abortus lipopolysaccharide in murine peritoneal macrophages acts as a down-regulator of t cell activation. | macrophages play a central role in host immune responses against pathogens by acting as both professional phagocytic cells and as fully competent apcs. we report here that the lps from the facultative intracellular gram-negative bacteria brucella abortus interferes with the mhc class ii ag presentation pathway. lps inhibits the capacity of macrophages to present hen egg lysozyme (hel) antigenic peptides to specific cd4(+) t cells but not those of ova to specific cd8(+) t cells. this defect was n ... | 2000 | 11046053 |
| a novel selenite- and tellurite-inducible gene in escherichia coli. | selenium is both an essential and a toxic trace element, and the range of concentrations between the two is extremely narrow. although tellurium is not essential and is only rarely found in the environment, it is considered to be extremely toxic. several hypotheses have been proposed to account for the toxic effects of selenite and tellurite. however, these potential mechanisms have yet to be fully substantiated. through screening of an escherichia coli luxab transcriptional gene fusion library, ... | 2000 | 11055951 |
| response of bali cattle (bos javanicus) to vaccination with brucella abortus strain 19 in west timor. | a trial was conducted in two villages (one containing cattle infected with brucellosis and one not containing infected cattle) in timor, indonesia to determine the serological response to vaccination with brucella abortus strain 19 in bali cattle (bos javanicus) (n = 599). mature female cattle were immunised with low-dose strain 19 (2x10(8)-6x10(8) colony forming units) and calves (6-12 months) with high-dose strain 19 (4x10(10)-12x10(10) colony forming units). other mature females and calves we ... | 2000 | 11058778 |
| legionella pneumophila replication vacuoles mature into acidic, endocytic organelles. | after ingestion by macrophages, legionella pneumophila inhibits acidification and maturation of its phagosome. after a 6-10-h lag period, the bacteria replicate for 10-14 h until macrophage lysis releases dozens of progeny. to examine whether the growth phase of intracellular l. pneumophila determines the fate of its phagosome, interactions between the endosomal network and pathogen vacuoles were analyzed throughout the primary infection period. surprisingly, as l. pneumophila replicated exponen ... | 2000 | 11067875 |
| maturation of incp pilin precursors resembles the catalytic dyad-like mechanism of leader peptidases. | the pilus subunit, the pilin, of conjugative incp pili is encoded by the trbc gene. incp pilin is composed of 78 amino acids forming a ring structure (r. eisenbrandt, m. kalkum, e.-m. lai, c. i. kado, and e. lanka, j. biol. chem. 274:22548-22555, 1999). three enzymes are involved in maturation of the pilin: lepb of escherichia coli for signal peptide removal and a yet-unidentified protease for removal of 27 c-terminal residues. both enzymes are chromosome encoded. finally, the inner membrane-ass ... | 2000 | 11073921 |
| deletions of structural glycoprotein e2 of classical swine fever virus strain alfort/187 resolve a linear epitope of monoclonal antibody wh303 and the minimal n-terminal domain essential for binding immunoglobulin g antibodies of a pig hyperimmune serum. | the major structural glycoprotein e2 of classical swine fever virus (csfv) is responsible for eliciting neutralizing antibodies and conferring protective immunity. the current structural model of this protein predicts its surface-exposed region at the n terminus with a short stretch of the c-terminal residues spanning the membrane envelope. in this study, the n-terminal region of 221 amino acids (aa) covering aa 690 to 910 of the csfv strain alfort/187 e2, expressed as a fusion product in escher ... | 2000 | 11090160 |
| the leishmania infantum acidic ribosomal protein lip2a induces a prominent humoral response in vivo and stimulates cell proliferation in vitro and interferon-gamma (ifn-gamma) production by murine splenocytes. | the acidic ribosomal proteins of the protozoan parasite leishmania infantum have been described as prominent antigens during both human and canine visceral leishmaniasis. in this study we present data showing that the intraperitoneal administration in balb/c mice of the leishmania lip2a protein, in the absence of any added adjuvants, elicited a strong humoral response as an indication that the protein is a potent immunogen. despite the evolutionary conservation of the acidic ribosomal proteins, ... | 2000 | 11091277 |
| a functional water channel protein in the pathogenic bacterium brucella abortus. | the gene for a new bacterial aquaporin, aqpx, was cloned from the pathogenic gram-negative bacterium brucella abortus. the gene was mapped on the large chromosome of b. abortus. it is flanked by one upstream and two downstream copies of the brucella repeated sequence bru-rs. prediction from the nucleotide sequence indicated that the protein is a member of the mip family, which comprises channels for water and/or solute transport. expression in xenopus oocytes and cryoelectron microscopy of esche ... | 2000 | 11101683 |
| immune response of buffaloes to vaccination with brucella abortus strain 19. | the immune response of buffalo calves and heifers to a full or half dose of brucella abortus strain 19 vaccine was studied. buffalo calves developed high serum agglutination test (sat) titres following full dose vaccination. these titres declined more rapidly in calves of six months of age than in calves of eleven to twelve months of age. specific immunoglobulin g titres, as measured by 2-mercaptoethanol-treated serum agglutination, declined much earlier than sat titres. buffalo heifers vaccinat ... | 2000 | 11107632 |
| the chvh locus of agrobacterium encodes a homologue of an elongation factor involved in protein synthesis. | the virulence of agrobacterium tumefaciens depends on both chromosome- and ti plasmid-encoded gene products. in this study, we characterize a chromosomal locus, chvh, previously identified by tnphoa mutagenesis and shown to be required for tumor formation. through dna sequencing and comparison of the sequence with identified sequences in the database, we show that this locus encodes a protein similar in sequence to elongation factor p, a protein thought to be involved in peptide bond synthesis i ... | 2001 | 11114898 |
| brucella suis-impaired specific recognition of phagosomes by lysosomes due to phagosomal membrane modifications. | brucella species are gram-negative, facultatively intracellular bacteria that infect humans and animals. these organisms can survive and replicate within a membrane-bound compartment in phagocytic and nonprofessional phagocytic cells. inhibition of phagosome-lysosome fusion has been proposed as a mechanism for intracellular survival in both types of cells. however, the biochemical mechanisms and microbial factors implicated in brucella maturation are still completely unknown. we developed two di ... | 2001 | 11119541 |
| role of mycobacterium tuberculosis copper-zinc superoxide dismutase. | superoxide dismutases (sods) play an important role in protection against oxidative stress and have been shown to contribute to the pathogenicity of many bacterial species. to determine the function of the mycobacterial copper and zinc-cofactored sod (cuznsod), we constructed and characterized mycobacterium tuberculosis and mycobacterium bovis bcg cuznsod null mutants. both strains were more sensitive to superoxides and hydrogen peroxide than were their respective parental strains. the survival ... | 2001 | 11119546 |
| aromatic compound-dependent brucella suis is attenuated in both cultured cells and mouse models. | the aroc gene of the facultative intracellular pathogen brucella suis was cloned and sequenced. the cloned aroc gene complements escherichia coli and salmonella enterica serovar typhimurium aroc mutants. a b. suis aroc mutant was found to be unable to grow in a defined medium without aromatic compounds. the mutant was highly attenuated in tissue culture (thp1 macrophages and hela cells) and murine virulence models. | 2001 | 11119550 |
| identification of the nik gene cluster of brucella suis: regulation and contribution to urease activity. | analysis of a brucella suis 1330 gene fused to a gfp reporter, and identified as being induced in j774 murine macrophage-like cells, allowed the isolation of a gene homologous to nika, the first gene of the escherichia coli operon encoding the specific transport system for nickel. dna sequence analysis of the corresponding b. suis nik locus showed that it was highly similar to that of e. coli except for localization of the nikr regulatory gene, which lies upstream from the structural nikabcde ge ... | 2001 | 11133934 |
| limited genetic diversity of brucella spp. | multilocus enzyme electrophoresis (mlee) of 99 brucella isolates, including the type strains from all recognized species, revealed a very limited genetic diversity and supports the proposal of a monospecific genus. in mlee-derived dendrograms, brucella abortus and a marine brucella sp. grouped into a single electrophoretic type related to brucella neotomae and brucella ovis. brucella suis and brucella canis formed another cluster linked to brucella melitensis and related to rhizobium tropici. th ... | 2001 | 11136777 |
| brucella abortus rb51 and hot saline extract from brucella ovis as antigens in a complement fixation test used to detect sheep vaccinated with brucella abortus rb51. | the efficacy of brucella abortus rb51 and hot saline extract (hse) from brucella ovis as antigens in complement fixation (cf) tests was comparatively evaluated in detecting immune responses of sheep vaccinated with b. abortus strain rb51. for this study, four 5-month-old sheep were vaccinated subcutaneously with 5 x 10(9) cfu of rb51, and two sheep received saline. serum samples collected at different times after vaccination were tested for the presence of antibodies to rb51 by a cf test with rb ... | 2001 | 11139204 |
| antigenic characterization of the fish pathogen flavobacterium psychrophilum. | flavobacteria are a poorly understood and speciated group of commensal bacteria and opportunistic pathogens. the psychrotroph flavobacterium psychrophilum is the etiological agent of rainbow trout fry syndrome and bacterial cold water disease, septicemic diseases that heavily impact salmonids. consequently, two verified but geographically diverse isolates were characterized phenotypically and biochemically. a facile typing system was devised which readily discriminated between closely related sp ... | 2001 | 11157240 |
| cloning of the soda gene from corynebacterium melassecola and role of superoxide dismutase in cellular viability. | the soda gene encoding the corynebacterium melassecola manganese-cofactored superoxide dismutase (sod) has been cloned in escherichia coli and sequenced. the gene is transcribed monocistronically; the predicted polypeptide is 200 amino acids long and associates in a homotetrameric, manganese-dependent form, able to complement an sod-deficient e. coli mutant. a second open reading frame, coding for a putative 217-amino-acid protein with high homology to peptide methionine sulfoxide reductases fro ... | 2001 | 11157941 |
| disruption of nuclear factor-interleukin-6, a transcription factor, results in severe mycobacterial infection. | nuclear factor-interleukin-6 (nf-il-6) is one of several nuclear transcription factors (nf-il-6, nf-kappab, pu.1, interferon-regulatory factor 1, egr-1, and stat-1). nf-il-6 and nf-kappab are expressed in macrophages and is induced by bacterial lipopolysaccharides. to evaluate whether nf-il-6 is required for the inflammatory immune response to mycobacterial infection, in which epithelioid macrophages comprise the leading cell population, we generated nf-il-6 knockout (ko) mutant mice. airborne i ... | 2001 | 11159172 |
| gene discovery through genomic sequencing of brucella abortus. | brucella abortus is the etiological agent of brucellosis, a disease that affects bovines and human. we generated dna random sequences from the genome of b. abortus strain 2308 in order to characterize molecular targets that might be useful for developing immunological or chemotherapeutic strategies against this pathogen. the partial sequencing of 1,899 clones allowed the identification of 1,199 genomic sequence surveys (gsss) with high homology (blast expect value < 10(-5)) to sequences deposite ... | 2001 | 11159979 |
| nucleotide sequence and analysis of conjugative plasmid pvt745. | the complete nucleotide sequence and genetic map of pvt745 are presented. the 25-kb plasmid was isolated from actinobacillus actinomycetemcomitans, a periodontal pathogen. two-thirds of the plasmid encode functions related to conjugation, replication, and replicon stability. among potential gene products with a high degree of similarity to known proteins are those associated with plasmid conjugation. it was shown that pvt745 derivatives not only mobilized a coresident nontransmissible plasmid, p ... | 2001 | 11160089 |
| conserved gene cluster at replication origins of the alpha-proteobacteria caulobacter crescentus and rickettsia prowazekii. | a 30-kb region surrounding the replication origin in caulobacter crescentus was analyzed. comparison to the genome sequence of another alpha-proteobacterium, rickettsia prowazekii, revealed a conserved cluster of genes (rp001, heme, hemh, and rp883) that overlaps the established origin of replication in c. crescentus and the putative origin of replication in r. prowazekii. the genes flanking this cluster differ between these two organisms. we therefore propose that this conserved gene cluster ca ... | 2001 | 11160121 |
| real-time detection of brucella abortus, brucella melitensis and brucella suis. | real-time pcr-based assays specific for brucella abortus, brucella melitensis and brucella suis were developed. the assays utilize an upstream primer that is derived from 3' end of the genetic element is 711, whereas the downstream primers and probes are designed from signature sequences specific to a species or a biovar. the pcr reactions were monitored for fluorescence resonance energy transfer by including two adjacent labeled probes that hybridize to the amplicons as they are formed. the ups ... | 2001 | 11162079 |
| development, testing and commercialization of a new brucellosis vaccine for cattle. | vaccines used against brucellosis do not generally protect completely against infection or abortion. genetic analysis has revealed differences in arrangements of dna sequences between these vaccine strains and the virulent parent strain and permits the specific identification of field isolates of b. abortus as wild-type or vaccine strain. b. abortus strain 19 is a low-virulence, live vaccine developed for use in cattle. although it is effective, strain 19 vaccine had a tropism for the placenta a ... | 2000 | 11193615 |
| cell-mediated and humoral immunity and phagocytic ability in chicken lines divergently selected for serum immunoglobulin m and g levels. | humoral and cell-mediated immunities and phagocytic ability were examined at the third and fourth generations of selection in two pairs of chicken lines (at 10 wk of age) that were divergently selected for levels of high serum ig m (him), low serum ig m (lim), high serum ig g (hig), and low serum ig g (lig). cell-mediated immunity was examined by splenomegaly assay at 12 wk of age. at 20 and 23 wk of age, 20 birds from the respective lines were injected brucella abortus (ba), and blood samples w ... | 2000 | 11194030 |
| immunity and protection against brucella abortus. | brucella abortus is an intracellular pathogen that causes disease in cattle and in humans. the response against b. abortus involves the whole gamut of the immune system, from innate to adaptive immunity resulting from stimulation of antigen-presenting cells, nk cells, cd4(+) and cd8(+) t cells, and b cells. | 2001 | 11226853 |
| a case of prosthetic mitral valve endocarditis caused by brucella abortus. | endocarditis is a rare but serious complication of brucellosis. we report here a case of brucella abortus endocarditis occurring on a prosthetic mitral valve. the diagnosis was established by positive serology, the presence of vegetation on the mitral prosthesis and isolation of b. abortus from the blood and valve cultures. the patient was successfully treated with combined medical and surgical therapy. | 2001 | 11234984 |
| survival of brucella abortus strain rb51 lyophilized and as liquid vaccine under different storage conditions. | brucella abortus strain rb51 (srb51) is a new cattle vaccine that is approved for use in the u.s. for prevention of brucellosis. at the present time, other countries are implementing or considering the use of srb51 vaccine in their brucellosis control programs. in the current study, the effect of three stabilizing media, two fill volumes (1 and 3 ml), and three storage temperatures (-25, 4 and 25 degrees c) on the viability of lyophilized srb51 over a 52 week period was determined. the effects o ... | 2000 | 11237356 |
| field validation of the use of rb51 as antigen in a complement fixation test to identify calves vaccinated with brucella abortus rb51. | in order to confirm the efficiency of an experimental rb51-based complement fixation (cf) test in identifying cattle vaccinated with brucella abortus strain rb51, 831 sera from 110 vaccinated and 48 unvaccinated hereford heifers of iowa, collected for studies conducted in different years, were sent to italy without coding to be tested in a cf test using rb51 as antigen. most of the calves, aged from 3 to 10 months, were vaccinated subcutaneously with the recommended dosage of 10(10) cfu of rb51 ... | 2001 | 11238226 |
| frequent exposure of mice to crude brucella abortus proteins down-regulates immune response. | mice repeatedly immunized via the intraperitoneal route with a brucella abortus antigen lost their ability to develop a strong in vitro lymphoproliferative response. this result correlates with a decreased tendency of the lymphoid population to produce interferon-gamma when stimulated in culture with the immunizing antigen. with respect to the humoral response, as the number of immunizations increased, the animals produced more specific immunoglobulin m and immunoglobulin g1 antibodies. it is po ... | 2000 | 11244868 |
| identification of new genes involved in the virulence of listeria monocytogenes by signature-tagged transposon mutagenesis. | listeria monocytogenes is a gram-positive, facultative intracellular pathogen that can cause severe food-born infections in humans and animals. we have adapted signature-tagged transposon mutagenesis to l. monocytogenes to identify new genes involved in virulence in the murine model of infection. we used transposon tn1545 carried on the integrative vector pat113. forty-eight tagged transposons were constructed and used to generate banks of l. monocytogenes mutants. pools of 48 mutants were assem ... | 2001 | 11254558 |
| salmonella enterica serovar typhimurium induces cell death in bovine monocyte-derived macrophages by early sipb-dependent and delayed sipb-independent mechanisms. | it was previously demonstrated that salmonella enterica serovar typhimurium induces cell death with features of apoptosis in murine macrophages. mice infected with salmonella serovar typhimurium develop systemic disease without diarrhea, whereas the infection in cattle and in humans is localized and characterized by diarrhea. considering these clinical disease expression differences between mice and cattle, we investigated whether serovar typhimurium is cytotoxic for bovine macrophages. macropha ... | 2001 | 11254586 |
| htra homologue of legionella pneumophila: an indispensable element for intracellular infection of mammalian but not protozoan cells. | legionella pneumophila replicates within alveolar macrophages, and possibly, alveolar epithelial cells and also within protozoa in the aquatic environment. here we characterize an l. pneumophila mutant defective in the htra/degp stress-induced protease/chaperone homologue and show that htra is indispensable for intracellular replication within mammalian macrophages and alveolar epithelial cells and for intrapulmonary replication in a/j mice. importantly, amino acid substitutions of two conserved ... | 2001 | 11254621 |
| secretion of listeriolysin by brucella suis inhibits its intramacrophagic replication. | the introduction into brucella suis 1330 of a plasmid allowing the heterologous expression of a hybrid cytolysin containing listeriolysin from listeria monocytogenes, and its export via the escherichia coli hemolysin secretion pathway, resulted in secretion of active listeriolysin monitored by erythrocyte lysis. in contrast to observations with the nonhemolytic control strain, the phagosomes of infected human monocytes containing the hemolytic b. suis were partially disrupted, and this strain fa ... | 2001 | 11254648 |
| complete genome sequence of caulobacter crescentus. | the complete genome sequence of caulobacter crescentus was determined to be 4,016,942 base pairs in a single circular chromosome encoding 3,767 genes. this organism, which grows in a dilute aquatic environment, coordinates the cell division cycle and multiple cell differentiation events. with the annotated genome sequence, a full description of the genetic network that controls bacterial differentiation, cell growth, and cell cycle progression is within reach. two-component signal transduction p ... | 2001 | 11259647 |
| essential role of the virb machinery in the maturation of the brucella abortus-containing vacuole. | in epithelial cells, the intracellular pathogen brucella abortus escapes from the endocytic pathway, exploits the autophagic machinery of the host cell and establishes a unique replication niche in the endoplasmic reticulum. the molecular mechanisms underlying these processes are still poorly understood. recently, a b. abortus type iv-related secretion system encoded by the virb operon has been described as being involved in the intracellular trafficking of the bacteria. in this study, we have a ... | 2001 | 11260139 |
| pathology of brucellosis in bison from yellowstone national park. | between february 1995 and june 1999, specimens from seven aborted bison (bison bison) fetuses or stillborn calves and their placentas, two additional placentas, three dead neonates, one 2-wk-old calf, and 35 juvenile and adult female bison from yellowstone national park (usa) were submitted for bacteriologic and histopathologic examination. one adult animal with a retained placenta had recently aborted. serum samples from the 35 juvenile and adult bison were tested for brucella spp. antibodies. ... | 2001 | 11272483 |
| evaluation of the fluorescence polarization assay and comparison to other serological assays for detection of brucellosis in cervids. | the complement fixation test (cft), competitive enzyme immunoassay (celisa), indirect enzyme immunoassay (ielisa) and fluorescence polarization assay (fpa) were evaluated for the detection of antibodies to brucella abortus and brucella suis biotype 4 in caribou (rangifer tarandus caribou), elk (cervus elapus), red deer (cervus elapus), and reindeer (rangifer tarandus tarandus). when combining the data the fpa and the celisa were determined to be the most suitable tests for serodiagnosis of cervi ... | 2001 | 11272484 |
| cloning, sequencing, and expression of interferon-gamma from elk in north america. | eradication of mycobacterium bovis relies on accurate detection of infected animals, including potential domestic and wildlife reservoirs. available diagnostic tests lack the sensitivity and specificity necessary for accurate detection, particularly in infected wildlife populations. recently, an in vitro diagnostic test for cattle which measures plasma interferon-gamma (ifn-gamma) levels in blood following in vitro incubation with m. bovis purified protein derivative has been enveloped. this tes ... | 2001 | 11272492 |
| serologic survey of brucella spp. antibodies in some marine mammals of north america. | a serologic survey of anti-brucella spp. antibodies was undertaken on 2,470 samples of 14 north american marine mammal species collected between 1984-97. serum or blood from eight species of cetaceans and six species of pinnipeds was sampled from pacific, atlantic, and arctic oceans. two competitive enzyme-linked immunosorbent assays (c-elisa's), using specific monoclonal antibodies to brucella abortus cell wall components, were used to detect anti-brucella spp. antibodies in the samples. sera f ... | 2001 | 11272509 |
| interruption of the cydb locus in brucella abortus attenuates intracellular survival and virulence in the mouse model of infection. | brucellosis is characterized by abortion in ruminants and a protracted undulant fever in humans, which often results in severe pathological manifestations. scant information exists about the molecular mechanisms employed by brucella abortus to combat host defenses or to persist and replicate within host cells. transposon (tn5) mutagenesis of b. abortus and the subsequent screening of mutants for sensitivity to killing in murine macrophages and in the mouse model led to the identification of muta ... | 2001 | 11274104 |
| characterization of brucella suis clpb and clpab mutants and participation of the genes in stress responses. | pathogens often encounter stressful conditions inside their hosts. in the attempt to characterize the stress response in brucella suis, a gene highly homologous to escherichia coli clpb was isolated from brucella suis, and the deduced amino acid sequence showed features typical of the clpb atpase family of stress response proteins. under high-temperature stress conditions, clpb of b. suis was induced, and an isogenic b. suis clpb mutant showed increased sensitivity to high temperature, but also ... | 2001 | 11274130 |
| bovine rotavirus nonstructural protein 4 produced by lactococcus lactis is antigenic and immunogenic. | rotavirus nonstructural protein 4 (nsp4) can induce diarrhea in mice. to get insight into the biological effects of nsp4, production of large quantities of this protein is necessary. we first tried to produce the protein in escherichia coli, but the nsp4 gene proved to be unstable. the capacity of the generally regarded as safe organism lactococcus lactis to produce nsp4 either intra- or extracellularly was then investigated by using the nisin-controlled expression system. production of recombin ... | 2001 | 11282586 |
| serum is the preferred clinical specimen for diagnosis of human brucellosis by pcr. | human brucellosis poses a significant public health problem in many developing countries and requires fast and accurate diagnosis. a pcr assay amplifying part of the 31-kda brucella abortus antigenic protein gene sequence was developed and applied to whole-blood and serum samples from 31 brucellosis patients and 45 healthy individuals. all patients except one had detectable brucella dna in either whole blood or serum (combined sensitivity, 97%), but the assay sensitivity was higher with serum sa ... | 2001 | 11283112 |
| cloning and characterisation of male in burkholderia pseudomallei. | no recombinant protein is available for serodiagnosis or skin test in the diagnosis of melioidosis. this report describes the cloning of the male gene, which encodes an immunogenic protein of burkholderia pseudomallei. bi-directional dna sequencing of male revealed that the gene contained a single open reading frame encoding 416 amino acid residues with a predicted molecular mass of 44.4 kda. blast analysis showed that the putative protein encoded by male is homologous to the maltose-binding pro ... | 2001 | 11289518 |
| stable transfection of the bovine nramp1 gene into murine raw264.7 cells: effect on brucella abortus survival. | genetically based natural resistance to brucellosis in cattle provides for novel strategies to control zoonotic diseases. bovine nramp1, the homologue of a murine gene (bcg), has been identified as a major candidate for controlling the in vivo resistant phenotype. we developed an in vitro model for expression of resistance- and susceptibility-associated alleles of bovine nramp1 as stable transgenes under the regulatory control of the bovine nramp1 promoter in the murine raw264.7 macrophage cell ... | 2001 | 11292730 |
| fluorescence polarization assay for the diagnosis of bovine brucellosis: adaptation to field use. | a fluorescence polarization assay (fpa) was used to test whole blood samples prepared by mixing blood cells from cattle without exposure to brucella abortus (b. abortus) with sera from animals with confirmed (bacteriologically) infection. a cut-off value between negative and positive values was initially established to be 87.2mp. this value was changed to 95mp to increase assay specificity without loss of sensitivity when testing blood samples from negative animals. the fpa technology was applie ... | 2001 | 11295336 |
| specificity of a polymerase chain reaction assay of a target sequence on the 31-kilodalton brucella antigen dna used to diagnose human brucellosis. | the aim of this study was to evaluate the specificity of a polymerase chain reaction assay for detecting brucella dna using primers specific for the amplification of a 223 bp region of the sequence encoding a 31 kda immunogenic brucella abortus protein (bcsp31). dna from all brucella strains, including type, reference, vaccine and field strains, were correctly amplified. with the exception of ochrobactrum spp., no other amplification was detected with a broad panel of microorganisms serologicall ... | 2001 | 11305467 |
| type iv secretion: intercellular transfer of macromolecules by systems ancestrally related to conjugation machines. | bacterial conjugation systems are highly promiscuous macromolecular transfer systems that impact human health significantly. in clinical settings, conjugation is exceptionally problematic, leading to the rapid dissemination of antibiotic resistance genes and other virulence traits among bacterial populations. recent work has shown that several pathogens of plants and mammals - agrobacterium tumefaciens, bordetella pertussis, helicobacter pylori and legionella pneumophila - have evolved secretion ... | 2001 | 11309113 |
| use of polymerase chain reaction to identify brucella abortus strain rb51 among brucella field isolates from cattle in italy. | brucella abortus strain rb51, a rough mutant of the b. abortus 2308 virulent strain, was recently approved in the united states as the official vaccine for brucellosis in cattle. following recent evidence of unauthorized use of rb51 vaccine in italy, where the use of vaccines for brucellosis is no longer allowed, the suitability of an rb51-specific polymerase chain reaction assay for identifying the rb51 strain among brucella field isolates from cattle in italy was investigated. the oligonucleot ... | 2001 | 11315520 |
| the ccrm dna methyltransferase of agrobacterium tumefaciens is essential, and its activity is cell cycle regulated. | dna methylation is now recognized as a regulator of multiple bacterial cellular processes. ccrm is a dna adenine methyltransferase found in the alpha subdivision of the proteobacteria. like the dam enzyme, which is found primarily in escherichia coli and other gamma proteobacteria, it does not appear to be part of a dna restriction-modification system. the ccrm homolog of agrobacterium tumefaciens was found to be essential for viability. overexpression of ccrm is associated with significant abno ... | 2001 | 11325934 |
| a homolog of the ctra cell cycle regulator is present and essential in sinorhizobium meliloti. | during development of the symbiotic soil bacterium sinorhizobium meliloti into nitrogen-fixing bacteroids, dna replication and cell division cease and the cells undergo profound metabolic and morphological changes. regulatory genes controlling the early stages of this process have not been identified. as a first step in the search for regulators of these events, we report the isolation and characterization of a ctra gene from s. meliloti. we show that the s. meliloti ctra belongs to the ctra-lik ... | 2001 | 11325950 |
| induction of mucosal immune response after intranasal or oral inoculation of mice with lactococcus lactis producing bovine beta-lactoglobulin. | the bovine beta-lactoglobulin (blg) is a major cow's milk allergen. here, we evaluated the immune response against blg induced in mice, using the organism lactococcus lactis, which has gras ("generally regarded as safe") status, as a delivery vehicle. the cdna of the blg gene, encoding blg, was expressed and engineered for either intra- or extracellular expression in l. lactis. using a constitutive promoter, the yield of intracellular recombinant blg (rblg) was about 20 ng per ml of culture. to ... | 2001 | 11329455 |
| immunopathology and ehrlichial propagation are regulated by interferon-gamma and interleukin-10 in a murine model of human granulocytic ehrlichiosis. | previous studies of human granulocytic ehrlichiosis (hge) suggest a role for host immune response in resolving infection and in causing histopathological lesions. we hypothesize that interferon (ifn)-gamma allows tissue injury that is suppressed by interleukin (il)-10 after initiation by ehrlichia infection. thus, parental c57bl/6, il-10-/-, and ifn-gamma-/- strains of mice were infected and then assayed for hepatic histopathological lesions, ehrlichial burden, and cytokine responses to ehrlichi ... | 2001 | 11337387 |
| identification and characterization of a second superoxide dismutase gene (sodm) from staphylococcus aureus. | a gene encoding superoxide dismutase (sod), sodm, from s. aureus was cloned and characterized. the deduced amino acid sequence specifies a 187-amino-acid protein with 75% identity to the s. aureus soda protein. amino acid sequence comparisons with known sods and relative insensitivity to hydrogen peroxide and potassium cyanide indicate that sodm most likely uses manganese (mn) as a cofactor. the sodm gene expressed from a plasmid rescued an escherichia coli double mutant (soda sodb) under condit ... | 2001 | 11344148 |
| identification of brucella abortus, b. canis, b. melitensis, and b. suis by carbon substrate assimilation tests. | by using the results of seven carbon substrate assimilation tests from the biotype 100 system (biomérieux, marcy-l'etoile, france), we correctly identified 79 (85.9%) of 92 brucella strains tested. the specificity of the method varied from 97.4 to 100% depending on the species. although a biological safety cabinet must be used, this method represents an easy and fast alternative for the identification of brucella species. | 2001 | 11348772 |
| mycobacterium bovis bcg reca deletion mutant shows increased susceptibility to dna-damaging agents but wild-type survival in a mouse infection model. | pathogenic microorganisms possess antioxidant defense mechanisms for protection from reactive oxygen metabolites which are generated during the respiratory burst of phagocytic cells. these defense mechanisms include enzymes such as catalase, which detoxifies reactive oxygen species, and dna repair systems, which repair damage resulting from oxidative stress. to (i) determine the relative importance of the dna repair system when oxidative stress is encountered by the mycobacterium tuberculosis co ... | 2001 | 11349014 |
| human peripheral blood t cells, monocytes, and macrophages secrete macrophage inflammatory proteins 1alpha and 1beta following stimulation with heat-inactivated brucella abortus. | heat-killed brucella abortus (hba) has been proposed as a carrier for therapeutic vaccines for individuals with immunodeficiency, due to its abilities to induce interleukin-2 (il-2) and gamma interferon (ifn-gamma) in both cd4(+) and cd8(+) t cells and to upregulate antigen-presenting cell functions (including il-12 production). in the current study, we investigated the ability of hba or lipopolysaccharide isolated from hba (lps-ba) to elicit beta-chemokines, known to bind to the human immunodef ... | 2001 | 11349047 |
| characterization of the groesl operon in listeria monocytogenes: utilization of two reporter systems (gfp and hly) for evaluating in vivo expression. | the ability of intracellular pathogens to sense and adapt to the hostile environment of the host is an important factor governing virulence. we have sequenced the operon encoding the major heat shock proteins groes and groel in the gram-positive food-borne pathogen listeria monocytogenes. the operon has a conserved orientation in the order groes groel. upstream of groes and in the opposite orientation is a gene encoding a homologue of the bacillus subtilis protein ydil, while downstream of groel ... | 2001 | 11349060 |
| intracellular survival of brucella spp. in human monocytes involves conventional uptake but special phagosomes. | brucella spp. are facultative intracellular parasites of various mammals, including humans, typically infecting lymphoid as well as reproductive organs. we have investigated how b. suis and b. melitensis enter human monocytes and in which compartment they survive. peripheral blood monocytes readily internalized nonopsonized brucellae and killed most of them within 12 to 18 h. the presence of brucella-specific antibodies (but not complement) increased the uptake of bacteria without increasing the ... | 2001 | 11349069 |
| experimental exposure of llamas (lama glama) to brucella abortus: humoral antibody response. | positive antibody reactions to brucella were observed in the sera of four llamas receiving brucella abortus strain 19 subcutaneously at 2-3 weeks post-exposure (pe) using five of eight conventional brucella serologic tests and an isu-elisa. positive brucella antibody reactions were detected in sera of four llamas exposed by intraocular instillation (ioi) of 1.02x10(8) (high dose) b. abortus strain 2308 at 16-35 days pe using seven of eight serologic tests or an isu-elisa. brucella antibody was a ... | 2001 | 11356322 |
| evaluating genome dynamics: the constraints on rearrangements within bacterial genomes. | inversions and translocations distinguish the genomes of closely related bacterial species, but most of these rearrangements preserve the relationship between the rearranged fragments and the axis of chromosome replication. within species, such rearrangements are found less frequently, except in the case of clinical isolates of human pathogens, where rearrangements are very frequent. | 2000 | 11380986 |
| activities of vire1 and the vire1 secretion chaperone in export of the multifunctional vire2 effector via an agrobacterium type iv secretion pathway. | agrobacterium tumefaciens uses a type iv secretion system to deliver oncogenic nucleoprotein particles and effector proteins, such as the multifunctional vire2 protein, to plant cells. in this study, we examined the function of vire1 and its product, the vire1 secretion chaperone, in mediating vire2 export. a nonpolar vire1 null mutant accumulated low levels of vire2, and trans expression of vire1 in this mutant only partially restored vire2 abundance. deletion of vire1 did not affect transcript ... | 2001 | 11395448 |
| establishing a direct role for the bartonella bacilliformis invasion-associated locus b (ialb) protein in human erythrocyte parasitism. | the invasion-associated locus a and b genes (ialab) of bartonella bacilliformis were previously shown to confer an erythrocyte-invasive phenotype upon escherichia coli, indirectly implicating their role in virulence. we report the first direct demonstration of a role for ialb as a virulence factor in b. bacilliformis. the presence of a secretory signal sequence and amino acid sequence similarity to two known outer membrane proteins involved in virulence suggested that ialb was an outer membrane ... | 2001 | 11401976 |
| deletion of wboa enhances activation of the lectin pathway of complement in brucella abortus and brucella melitensis. | brucella spp. are gram-negative intracellular pathogens that survive and multiply within phagocytic cells of their hosts. smooth organisms present o polysaccharides (ops) on their surface. these ops help the bacteria avoid the bactericidal action of serum. the wboa gene, coding for the enzyme glycosyltransferase, is essential for the synthesis of o chain in brucella. in this study, the sensitivity to serum of smooth, virulent brucella melitensis 16m and b. abortus 2308, rough wboa mutants vtrm1, ... | 2001 | 11401980 |
| cloning, overexpression, purification, and immunobiology of an 85-kilodalton outer membrane protein from haemophilus ducreyi. | we have identified an 85-kda outer membrane protein that is expressed by all tested strains of haemophilus ducreyi. studies of related proteins from other pathogenic bacteria, including haemophilus influenzae, pasteurella multocida, neisseria gonorrhoeae, neisseria meningitidis, and shigella dysenteriae, suggested a role for these proteins in pathogenesis and immunity. in keeping with the first such described protein from haemophilus influenzae type b, we termed the h. ducreyi protein d15. the g ... | 2001 | 11401984 |
| brucella abortus cyclic beta-1,2-glucan mutants have reduced virulence in mice and are defective in intracellular replication in hela cells. | null cyclic beta-1,2-glucan synthetase mutants (cgs mutants) were obtained from brucella abortus virulent strain 2308 and from b. abortus attenuated vaccinal strain s19. both mutants show greater sensitivity to surfactants like deoxycholic acid, sodium dodecyl sulfate, and zwittergent than the parental strains, suggesting cell surface alterations. although not to the same extent, both mutants display reduced virulence in mice and defective intracellular multiplication in hela cells. the b. abort ... | 2001 | 11401996 |
| salmonella-induced cell death is not required for enteritis in calves. | salmonella enterica serovar typhimurium causes cell death in bovine monocyte-derived and murine macrophages in vitro by a sipb-dependent mechanism. during this process, sipb binds and activates caspase-1, which in turn activates the proinflammatory cytokine interleukin-1beta through cleavage. we used bovine ileal ligated loops to address the role of serovar typhimurium-induced cell death in induction of fluid accumulation and inflammation in this diarrhea model. twelve perinatal calves had 6- to ... | 2001 | 11402005 |
| presence of escherichia coli o157:h7 in ground beef and ground baby beef meat. | a total of 114 beef and baby beef samples were examined. the samples included ground baby beef, mixed ground baby beef and pork, and chopped and shaped meat. the samples were analyzed from 30 different grocery stores in zagreb, croatia. the object of this study was to evaluate the prevalence of escherichia coli o157:h7 in the samples that can enhance the potential risk of outbreaks of hemorrhagic colitis and hemolytic uremic syndrome. the results in all tested samples of e. coli o157:h7 were neg ... | 2001 | 11403139 |
| afipia felis induces uptake by macrophages directly into a nonendocytic compartment. | afipia felis is a gram-negative bacterium that causes some cases of human cat scratch disease. a. felis can survive and multiply in several mammalian cell types, including macrophages, but the precise intracellular compartmentalization of a. felis-containing phagosomes is unknown. here, we demonstrate that, in murine macrophages, most a. felis-containing phagosomes exclude lysosomal tracer loaded into macrophage lysosomes before, as well as endocytic tracer loaded after, establishment of an infe ... | 2001 | 11404461 |
| energy-dependent conformational change in the tola protein of escherichia coli involves its n-terminal domain, tolq, and tolr. | tolq, tolr, and tola inner membrane proteins of escherichia coli are involved in maintaining the stability of the outer membrane. they share homology with the exbb, exbd, and tonb proteins, respectively. the last is involved in energy transduction between the inner and the outer membrane, and its conformation has been shown to depend on the presence of the proton motive force (pmf), exbb, and exbd. using limited proteolysis experiments, we investigated whether the conformation of tola was also a ... | 2001 | 11418549 |
| comparison of an indirect elisa with the brucella milk ring test for detection of antibodies to brucella abortus in bulk milk samples. | an indirect enzyme-linked immunosorbent assay (elisa) for the detection of brucella abortus antibodies in bovine bulk milk samples was evaluated. about 31 individual milk samples from b. abortus infected cows were diluted into bulk milk from a brucellosis free herd. individual milk samples obtained from 96 negative or positive herds to elisa or brucella ring test (brt), were tested by elisa. all positive cows were bled and serum samples were tested by the complement-fixation test (cft) which was ... | 2001 | 11423195 |
| use of recombinant bp26 protein in serological diagnosis of brucella melitensis infection in sheep. | previously a brucella protein named cp28, bp26, or omp28 has been identified as an immunodominant antigen in infected cattle, sheep, goats, and humans. in the present study we evaluated antibody responses of infected and b. melitensis rev.1-vaccinated sheep to the bp26 protein using purified recombinant bp26 protein produced in escherichia coli in an indirect enzyme-linked immunosorbent assay (i-elisa). the specificity of the i-elisa determined with sera from healthy sheep (n = 106) was 93%. the ... | 2001 | 11427425 |
| groel encodes a highly antigenic protein in burkholderia pseudomallei. | no recombinant protein is available for serodiagnosis of melioidosis. in this study, we report the cloning of the groel gene, which encodes an immunogenic protein of burkholderia pseudomallei. bidirectional dna sequencing of groel revealed that the gene contained a single open reading frame encoding 546 amino acid residues with a predicted molecular mass of 57.1 kda. basic local alignment search tool analysis showed that the putative protein encoded by groel is homologous to the chaperonins enco ... | 2001 | 11427437 |
| protection of balb/c mice against brucella abortus 544 challenge by vaccination with bacterioferritin or p39 recombinant proteins with cpg oligodeoxynucleotides as adjuvant. | the p39 and the bacterioferrin (bfr) antigens of brucella melitensis 16m were previously identified as t dominant antigens able to induce both delayed-type hypersensivity in sensitized guinea pigs and in vitro gamma interferon (ifn-gamma) production by peripheral blood mononuclear cells from infected cattle. here, we analyzed the potential for these antigens to function as a subunitary vaccine against brucella abortus infection in balb/c mice, and we characterized the humoral and cellular immune ... | 2001 | 11447155 |
| major outer membrane protein omp25 of brucella suis is involved in inhibition of tumor necrosis factor alpha production during infection of human macrophages. | brucella spp. can establish themselves and cause disease in humans and animals. the mechanisms by which brucella spp. evade the antibacterial defenses of their host, however, remain largely unknown. we have previously reported that live brucellae failed to induce tumor necrosis factor alpha (tnf-alpha) production upon human macrophage infection. this inhibition is associated with a nonidentified protein that is released into culture medium. outer membrane proteins (omps) of gram-negative bacteri ... | 2001 | 11447156 |
| cu,zn superoxide dismutase of mycobacterium tuberculosis contributes to survival in activated macrophages that are generating an oxidative burst. | macrophages produce reactive oxygen species and reactive nitrogen species that have potent antimicrobial activity. resistance to killing by macrophages is critical to the virulence of mycobacterium tuberculosis. m. tuberculosis has two genes encoding superoxide dismutase proteins, soda and sodc. sodc is a cu,zn superoxide dismutase responsible for only a minor portion of the superoxide dismutase activity of m. tuberculosis. however, sodc has a lipoprotein binding motif, which suggests that it ma ... | 2001 | 11447176 |
| the toxoplasma gondii protein rop2 mediates host organelle association with the parasitophorous vacuole membrane. | toxoplasma gondii replicates within a specialized vacuole surrounded by the parasitophorous vacuole membrane (pvm). the pvm forms intimate interactions with host mitochondria and endoplasmic reticulum (er) in a process termed pvm-organelle association. in this study we identify a likely mediator of this process, the parasite protein rop2. rop2, which is localized to the pvm, is secreted from anterior organelles termed rhoptries during parasite invasion into host cells. the nh(2)-terminal domain ... | 2001 | 11448993 |
| molecular characterization of chromosomal class c beta-lactamase and its regulatory gene in ochrobactrum anthropi. | ochrobactrum anthropi, formerly known as cdc group vd, is an oxidase-producing, gram-negative, obligately aerobic, non-lactose-fermenting bacillus of low virulence that occasionally causes human infections. it is highly resistant to all beta-lactams except imipenem. a clinical isolate, slo74, and six reference strains were tested. mics of penicillins, aztreonam, and most cephalosporins tested, including cefotaxime and ceftazidime, were >128 microg/ml and of cefepime were 64 to >128 microg/ml. cl ... | 2001 | 11451692 |
| molecular, antigenic, and functional analyses of omp2b porin size variants of brucella spp. | omp2a and omp2b are highly homologous porins present in the outer membrane of the bacteria from the genus brucella, a facultative intracellular pathogen. the genes coding for these proteins are closely linked in the brucella genome and oriented in opposite directions. in this work, we present the cloning, purification, and characterization of four omp2b size variants found in various brucella species, and we compare their antigenic and functional properties to the omp2a and omp2b porins of bruce ... | 2001 | 11466287 |
| il-12 induction by a th1-inducing adjuvant in vivo: dendritic cell subsets and regulation by il-10. | il-12 induction is critical for immune responses against many viruses and intracellular bacterial pathogens. recent studies suggest that il-12-secreting dendritic cells (dc) are potent th1-inducing apc. however, controversy exists concerning the function of dc subsets. murine studies have suggested that cd8(+) dc preferentially induce th1 responses, whereas cd8(-) dc induce th2 development; in this model, different dc subsets prime different responses. alternatively, the propensity of dc subsets ... | 2001 | 11466361 |
| brucellosis among animals and human contacts in eastern sudan. | to study the relative frequency of brucellosis among domestic animals in kassala state, sudan, in the year 1999 and compare the results of previous studies since 1908. also to study the frequency rates of the disease in animal contacts in the area. | 2001 | 11479636 |
| oral vaccination of sexually mature pigs with brucella abortus vaccine strain rb51. | to develop a novel oral vaccine delivery system for swine, using the rough vaccine strain of brucella abortus. | 2001 | 11497459 |
| kinetics of bartonella birtlesii infection in experimentally infected mice and pathogenic effect on reproductive functions. | the kinetics of infection and the pathogenic effects on the reproductive function of laboratory mice infected with bartonella birtlesii recovered from an apodemus species are described. b. birtlesii infection, as determined by bacteremia, occurred in balb/c mice inoculated intravenously. inoculation with a low-dose inoculum (1.5 x 10(3) cfu) induced bacteremia in only 75% of the mice compared to all of the mice inoculated with higher doses (> or =1.5 x 10(4)). mice became bacteremic for at least ... | 2001 | 11500400 |
| ontogeny of th1 memory responses against a brucella abortus conjugate. | protective immune responses to intracellular pathogens such as brucella abortus are characteristically th1-like. recently we demonstrated that heat-killed b. abortus (hkba), a strong th1 stimulus, conjugated to ovalbumin (hkba-ova), but not b. abortus alone, can alter the antigen-specific cytokine profile from th2- to th1-like. in this report we study the ability of a single injection of b. abortus to switch a th2 to a th1 response in immature mice. one-day- and 1-week-old mice were given a sing ... | 2001 | 11500412 |
| induction of specific cytotoxic lymphocytes in mice vaccinated with brucella abortus rb51. | a safe, more sensitive, nonradioactive, neutral red uptake assay was adopted to replace the traditional 51cr release assay for detection of brucella-specific cytotoxic t lymphocyte (ctl) activity. our studies indicated that brucella abortus strain rb51 vaccination of mice induced specific ctls against both strain rb51- and strain 2308-infected j774.a1 macrophages but not against listeria monocytogenes-infected j774.a1 cells. the antigen-specific cytotoxic activity was exerted by t lymphocytes bu ... | 2001 | 11500423 |
| conserved degp protease in gram-positive bacteria is essential for thermal and oxidative tolerance and full virulence in streptococcus pyogenes. | the degp protease, a multifunctional chaperone and protease, has been shown to be essential for virulence in gram-negative pathogens such as salmonella enterica serovar typhimurium, brucella abortus, yersinia enterocolitica, and pseudomonas aeruginosa. the function of degp in pathogenesis appears to be the degradation of damaged proteins that accumulate as a result of the initial host response to infection, which includes the release of reactive oxygen intermediates. additionally, the degp prote ... | 2001 | 11500427 |
| opsonized virulent edwardsiella tarda strains are able to adhere to and survive and replicate within fish phagocytes but fail to stimulate reactive oxygen intermediates. | edwardsiella tarda is responsible for hemorrhagic septicemia (edwardsiellosis) in fish and also causes diseases in higher vertebrates such as birds, reptiles, and mammals, including humans. interactions of e. tarda with blue gourami phagocytes were studied by light microscopy as well as by adherence, intracellular replication, and superoxide anion assays. both nonopsonized virulent (ppd130/91 and al9379) and avirulent (ppd125/87 and ppd76/87) bacteria could adhere to and survive and replicate wi ... | 2001 | 11500445 |
| porphyromonas gingivalis traffics to autophagosomes in human coronary artery endothelial cells. | porphyromonas gingivalis is a periodontal pathogen that also localizes to atherosclerotic plaques. our previous studies demonstrated that p. gingivalis is capable of invading endothelial cells and that intracellular bacteria are contained in vacuoles that resemble autophagosomes. in this study, we have examined the trafficking of p. gingivalis 381 to the autophagic pathway. p. gingivalis 381 internalized by human coronary artery endothelial (hcae) cells is located within vacuoles morphologically ... | 2001 | 11500446 |
| brucella abortus htra functions as an authentic stress response protease but is not required for wild-type virulence in balb/c mice. | a second mutation has recently been identified in the previously described brucella abortus htra mutant phe1. as a result of this finding, a new b. abortus htra mutant, designated rwp11, was constructed to evaluate the biological function of the brucella htra protease. rwp11 is more sensitive to oxidative killing in vitro and less resistant to killing by cultured murine neutrophils and macrophages than the virulent parental strain 2308 but is not attenuated in balb/c mice through 4 weeks postinf ... | 2001 | 11500472 |
| health protocol for translocation of free-ranging elk. | when considering an elk (cervus elaphus) restoration program, wildlife managers must evaluate the positive and negative elements of translocation. we prepared this protocol to give an overview of health considerations associated with translocation of elk, with an emphasis on movement of free-ranging elk from western north america to the southeastern usa. we evaluated infectious agents and ectoparasites reported in elk from two perspectives. first, we made a qualitative estimate of the ability of ... | 2001 | 11504216 |
| experimental infection of nontarget species of rodents and birds with brucella abortus strain rb51 vaccine. | the brucella abortus vaccine strain rb51 (srb51) is being considered for use in the management of bnucellosis in wild bison (bison bison) and elk (cervus elaphus) populations in the greater yellowstone area (usa). evaluation of the vaccines safety in non-target species was considered necessary prior to field use. between june 1998 and december 1999, ground squirrels (spermophilus richardsonii, n = 21), deer mice (peromyscus maniculatus, n = 14), prairie voles (microtus ochrogaster, n = 21), and ... | 2001 | 11504226 |
| safety of brucella abortus strain rb51 in deer mice. | brucella abortus strain rb51 is an approved brucellosis vaccine for use in cattle that may have potential as an oral vaccine for use in elk (cervus elaphus) and/or bison (bison bison). this study was designed to determine effects of strain rb51 on deer mice (peromyscus maniculatus), a nontarget species that could have access to treated baits in a field situation. in february 1994, 90 mice were orally dosed or intraperitoneally injected with 1 x 10(8) colony forming units strain rb51 and 77 contr ... | 2001 | 11504238 |
| serological evidence of brucellosis among predisposed patients with pyrexia of unknown origin in the north eastern nigeria. | brucellosis is the zoonosis of world wide distribution and common cause of economic loss and ill health among animals and human populations. patients with pyrexia of unknown origin (puo) who were predisposed to brucellosis through rearing of animals and consumption of different animal products were tested for presence of brucella abortus antibodies using rose bengal and serum agglutination antigens. twenty six (5.2%) of the 500 patients had b. abortus antibody. the high titres of 320, 640 and 12 ... | 2001 | 11505741 |
| fluorescence polarization assay for the diagnosis of brucellosis: a review. | fluorescence polarization assay (fpa) is based on the rotational differences between a small soluble antigen molecule in solution (labelled with a fluorochrome) and the antigen molecule complexed with its antibody. a small molecule will rotate randomly at a rapid rate, resulting in rapid depolarization of light, while a larger complex molecule will rotate slower and depolarize light at a reduced rate. the rate change in depolarization can be measured. the fpa is a homogeneous assay which does no ... | 2001 | 11506271 |
| validation of the fluorescence polarization assay for detection of milk antibody to brucella abortus. | a fluorescence polarization assay (fpa) for detection of antibody to brucella abortus in individual milk samples was developed and validated. samples from 190 cattle from which b. abortus was isolated; milk samples from cattle in herds infected with b. abortus (n = 1,086) and positive in the milk ring test (mrt), as well as milk samples from canadian cattle (with no evidence of brucellosis, n = 2,974) were tested by the indirect enzyme immunoassay (ielisa) and the fpa. the sensitivity (based on ... | 2001 | 11506272 |