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effects of pasteurella haemolytica a1 leukotoxin on bovine neutrophils: degranulation and generation of oxygen-derived free radicals.to further define the role of pasteurella haemolytica a1 leukotoxin in the pathogenesis of bovine pneumonic pasteurellosis, its in vitro effects on bovine neutrophils were investigated. leukotoxin-containing culture supernatant, from p. haemolytica, stimulated a neutrophil respiratory burst as measured by the generation of oxygen-derived free radicals o2- and h2o2. this effect was immediate because preincubation of neutrophils with the culture supernatant for 5 min or longer substantially suppre ...19921321532
characterization of a neutralizing monoclonal antibody to pasteurella haemolytica leukotoxin.six hybridoma clones producing monoclonal antibodies (mabs) reactive with pasteurella haemolytica a1 leukotoxin were derived from mice immunized with leukotoxin excised from sodium dodecyl sulfate-polyacrylamide gels. of the six mabs, only one, ltx-2, neutralized leukotoxin in a bl-3 cell cytotoxicity assay. mab ltx-2 blocked association of a1 leukotoxin to bl-3 cells, as measured by flow cytometric analysis. the epitope recognized by ltx-2 was localized to the carboxyl half of the native protei ...19921373398
pasteurella haemolytica leukotoxin inhibits mitogen-induced bovine peripheral blood mononuclear cell proliferation in vitro.in this study we demonstrate that partially purified pasteurella haemolytica leukotoxin inhibits the proliferative response of bovine peripheral blood mononuclear cells (pbmc) to mitogens in vitro. inhibition of pbmc proliferation did not appear to be due to cell death. addition of a neutralizing anti-leukotoxin monoclonal antibody restored a normal proliferative response.19921522801
increased elastase activity in nasal mucus associated with nasal colonization by pasteurella haemolytica in infectious bovine rhinotracheitis virus-infected calves.four healthy calves were inoculated with pasteurella haemolytica serotype 1 by instillation of a broth culture into the middle nasal meatus of the left nostril. four weeks later, calves were exposed to infectious bovine rhinotracheitis virus by aerosol into both nostrils. all calves became ill, from approximately day 3 through day 10 after virus exposure, and shed increased amounts of nasal mucus. two calves were induced to shed p haemolytica by the virus infection, and 2 calves required reinocu ...19921524285
causes of mortality and parasites and incidental lesions in dolphins and whales from british waters.detailed post mortem examinations were carried out on 18 dolphins and whales found dead on the coast of the united kingdom. the commonest causes of death were pneumonia and entanglement in fishing gear. of the non-fatal conditions, parasitoses of various organs were common and there was a wide variety of other conditions. in total 124 diseases and other lesions were found, giving an average of 6.9 conditions per animal.19921496768
an analysis of the codon usage of pasteurella haemolytica a1.analysis of approximately 17 kbp of nucleotide sequences from three different regions of the genome of pasteurella haemolytica a1 showed that the mol% g+c of p. haemolytica a1 dna is 38.5%. when only the coding sequences (approx. 10 kbp) were analysed, a similar value of 38.8% was obtained. a comparison of the relative synonymous codon usage values of the cloned genes showed that p. haemolytica a1 has a very different codon usage pattern from that of escherichia coli.19921478451
pharmacokinetic evaluation of ceftiofur in serum, tissue chamber fluid and bronchial secretions from healthy beef-bred calves.ceftiofur is a new broad spectrum cephalosporin marketed for the treatment of acute bovine respiratory disease. in this investigation ceftiofur was administered by intramuscular injection, at 24 h intervals, to healthy beef-bred calves for four days at dosages of 2.2 and 4.4 mg/kg of body weight, with 4 wk intervals between dosing regimens. serum, tissue chamber fluid (tcf), and bronchial secretion (bs) concentrations of ceftiofur were measured by microbiological assay after the first and fourth ...19921477795
distinct plasmid profiles of pasteurella haemolytica serotypes and the characterization and amplification in escherichia coli of ampicillin-resistance plasmids encoding rob-1 beta-lactamase.thirty-five isolates of pasteurella haemolytica from cattle or sheep were screened for the presence of plasmids and for resistance to a range of antibiotics. eight strains (four of serotype a1, three of serotype a2 and one untypable) contained plasmid dna and isolates of the same serotype had similar plasmid profiles, which were different from those of the other serotypes. all but one of the plasmid-bearing strains were isolated from pneumonic animals or from animals in contact with pneumonic ca ...19921527493
a comparison of the intratracheal, intravenous and intratonsillar routes of inoculation of goats with pasteurella haemolytica. 19921466144
ovine pulmonary surfactant induces killing of pasteurella haemolytica, escherichia coli, and klebsiella pneumoniae by normal serum.pulmonary surfactant has been shown to play an increasingly important role in bacterial clearance at the alveolar surface in the lung. this study describes a bactericidal mechanism in which ovine pulmonary surfactant induces killing of pasteurella haemolytica by normal serum. to demonstrate killing, six bacterial species were incubated first with pulmonary surfactant for 60 min at 37 degrees c and then with serum for an additional 60 min at 37 degrees c. p. haemolytica type a1 strains 82-25 and ...19921452351
construction of a broad host range shuttle vector for gene cloning and expression in actinobacillus pleuropneumoniae and other pasteurellaceae.we have constructed a pair of broad host range expression vectors, pjff224-nx and pjff224-xn, based on plasmid rsf1010, which enable cloning and efficient expression of genes in actinobacillus pleuropneumoniae and pasteurella haemolytica and in escherichia coli. the vectors consist of the minimal autonomous replicon of the broad host range plasmid rsf1010 and a type ii chloramphenicol acetyl transferase gene for chloramphenicol resistance selection. in addition, they contain a gene expression ca ...19921448612
nuclear-magnetic-resonance analysis of the capsular antigen of actinobacillus pleuropneumoniae serotype 9. its identity with the capsular antigen of escherichia coli k62 (k2ab), neisseria meningitidis serogroup h and pasteurella haemolytica serotype t15.the specific capsular antigen of actinobacillus pleuropneumoniae serotype 9 was characterized by one-dimensional and two-dimensional high-field nuclear-magnetic-resonance methods, and by chemical analyses, as a teichoic-acid-type polymer of a repeating unit having the structure [formula: see text] the basic polymer structure is identical to capsular antigens of neisseria meningitidis group h, escherichia coli k62 (k2ab) and pasteurella haemolytica serotype t15.19921446664
co-migrating and shared antigens of selected pasteurella haemolytica untypable strains.bacterial cell envelope preparations from eight untypable strains of pasteurella haemolytica were compared by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and immunoblotting with rabbit antisera prepared against the eight untypable strains (one untypable strain per rabbit) and with cattle antisera prepared against p. haemolytica serotypes 1, 2, 5, 6, 9 and against one heterologous untypable strain. numerous comigrating and shared antigens were recognized by the eight rabbit antiser ...19921413477
comparison of antibody responses in cattle to outer membrane proteins from pasteurella haemolytica serotype 1 and from eight untypeable strains.membrane associated proteins from 8 untypeable pasteurella haemolytica strains were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and compared with those of p haemolytica serotypes 1 and 2. cattle antisera obtained from p haemolytica serotype 1 vaccine trials were used in immunoblotting assays to compare the membrane proteins from the 8 untypeable strains with those from p haemolytica serotypes 1 and 2. densitometry was used to identify bands, and using linear regression ...19921378250
antigenic analysis of iron-regulated proteins in pasteurella haemolytica a and t biotypes by immunoblotting reveals biotype-specific epitopes.the antigenic relationships of the iron-regulated proteins (irps) in pasteurella haemolytica a and t biotype strains were examined by sds-page and immunoblotting. p. haemolytica cells of the a biotype, grown under conditions of iron-limitation, expressed two irps, of 35 and 70 kda. all t biotype strains expressed irps with slightly different molecular masses of 37 and 78 kda. immunoblotting of all 16 p. haemolytica serotypes was carried out using a panel of polyclonal and monoclonal antibodies r ...19921373434
cleavage of the cell-surface o-sialoglycoproteins cd34, cd43, cd44, and cd45 by a novel glycoprotease from pasteurella haemolytica.the study of structural/functional characteristics of the cell-surface glycoproteins of leukocytes has led to a better understanding of the differentiation and maturation of hematopoietic cells. we have assessed the ability of a unique metalloprotease that is secreted by the bovine fibrinous pneumonia pathogen pasteurella haemolytica, to cleave cell-surface glycoproteins expressed on human leukocytes. biochemical analysis shows that the o-glycosylated cell surface ag cd34, cd43 (leukosialin), cd ...19921371528
serological titers to bovine herpesvirus 1, bovine viral diarrhea virus, parainfluenza 3 virus, bovine respiratory syncytial virus and pasteurella haemolytica in feedlot calves with respiratory disease: associations with bacteriological and pulmonary cytological variables.acute and convalescent serum samples were taken from 59 calves with signs of respiratory disease (cases) and 60 clinically normal animals (controls) during their first month in the feedlot. sera were analyzed for antibodies to bovine parainfluenza 3 (pi3) virus by hemagglutination inhibition, to bovine viral diarrhea (bvd) virus, bovine respiratory syncytial (brs) virus and bovine herpesvirus 1 (bhv1) by virus neutralization, and to pasteurella haemolytica by indirect agglutination (phia) and cy ...19921335831
characterization of plasmids with antimicrobial resistant genes in pasteurella haemolytica a1.two r plasmids, pyfc1 and pyfc2, from pasteurella haemolytica a1 encoding sulfonamide, streptomycin (pyfc1), and ampicillin (pyfc2) resistances have been characterized by restriction endonuclease digestions, subcloning or dna sequencing. pyfc1 consists of 4225 bp and is 51.9% in at content. physical mapping indicated a highly conserved region of restriction sites among pyfc1, rsf1010, pgs05, pfm739, phd148 and pgs03b. pyfc1 encoded a dihydropteroate synthase (29.8 kda), and streptomycin kinase ( ...19921333838
using ribosomal rna gene restriction patterns in distinguishing isolates of pasteurella haemolytica from bighorn sheep (ovis canadensis).pasteurella haemolytica isolates (n = 31) from two isolated captive herds of rocky mountain bighorn sheep (ovis canadensis canadensis) were characterized and compared phenotypically (biotype, serotype, hemolytic activity) and by a genomic fingerprinting method known as ribotyping. seven to nine distinct phenotypes were observed. depending on the method used for serotyping, one to three phenotypes were common to both herds. eighteen isolates, recovered from both herds, were non-hemolytic, biotype ...19921324994
pasteurella haemolytica leukotoxin enhances production of leukotriene b4 and 5-hydroxyeicosatetraenoic acid by bovine polymorphonuclear leukocytes.the influence of the leukotoxin of pasteurella haemolytica on the generation of arachidonic acid metabolites by bovine polymorphonuclear leukocytes (pmns) was investigated. pmns released 5-, 12-, and 15-hydroxyeicosatetraenoic acids (5-, 12-, and 15-hete) and leukotriene b4 (ltb4) upon stimulation with arachidonic acid. the leukotoxin preparations dose dependently enhanced the release of the 5-lipoxygenase products 5-hete and ltb4 in arachidonic acid-stimulated pmns, whereas the release of 12- a ...19921322370
pasteurella haemolytica diagnosis questioned. 19921298273
lipopolysaccharide heterogeneity in pasteurella haemolytica isolates from cattle and sheep.lipopolysaccharide (lps) from 40 isolates of pasteurella haemolytica, comprising 23 serotype a1, seven serotype a2, one serotype t4, one serotype t10 and eight untypable isolates, obtained from diseased and healthy cattle or sheep, was characterized by sds-page and western blotting. ten different sds-page lps profiles, five smooth and five rough, were identified among the biotype a and untypable isolates and designated lps types 1-10. lps types 1 and 2 were smooth, had similar o-antigen banding- ...19921282533
a characterization of monoclonal antibodies prepared against pasteurella haemolytica serotype 1 surface antigens.the production and characterization of monoclonal antibodies against pasteurella haemolytica serotype 1 is described. ten monoclonal antibodies were produced and divided, on the basis of their properties, into six different groups. one produced bacteria agglutination only of p. haemolytica serotype 1. three antibodies bound with p. haemolytica serotypes 1, 5-8 and 12 and the antigen was identified in immunoblots as lipopolysaccharide. two antibodies bound p. haemolytica serotypes 1, 2, 5-8 and 1 ...19921280877
the glycoprotease of pasteurella haemolytica a1 eliminates binding of myeloid cells to p-selectin but not to e-selectin.hl-60 cells and neutrophils treated with the glycoprotease from pasteurella haemolytica a1, an enzyme which is specific for o-sialoglycoproteins, were found to be incapable of binding p-selectin but still bound e-selectin. comparative analysis of [35-s] cysteine labeled proteins from hl-60 cells by 2-dimensional electrophoresis indicated that two major proteins with m(r) 100 and 115 kd were significantly removed from cells which had been treated.19921280121
sequential development of antigens and toxins of pasteurella haemolytica serotype 1 grown in cell culture medium.pasteurella haemolytica was grown in nonsupplemented cell culture medium, or in medium supplemented with bovine serum albumin (bsa) for 24 hours. the production of leukotoxin (lkt) and endotoxin was sequentially evaluated, as were bacterial antigens associated with bacterial cell lysates and culture supernates. supplementation of medium with bsa had no effect on bacterial growth curves; however, lkt activity was detected earlier and was greater in culture supernates from bsa-supplemented media t ...19921524287
use of an indwelling bronchial catheter model of bovine pneumonic pasteurellosis for evaluation of therapeutic efficacy of various compounds.a model of bovine pneumonic pasteurellosis, using an indwelling bronchial catheter for inoculation and subsequent lavage of a single main stem bronchus of the lung, was evaluated in a preliminary efficacy trial of an experimental therapeutic compound. inoculation of 10(7) pasteurella haemolytica organisms into the bronchus consistently induced a focal pneumonic lesion with typical morphology of pneumonic pasteurellosis in the left or right caudal lung lobe. the experimental treatment caused sign ...19921524292
response of pasteurella haemolytica to erythromycin and dexamethasone in calves with established infection.a subcutaneous soft tissue infection model in calves was used to study the in vivo response of pasteurella haemolytica to erythromycin and dexamethasone. two tissue chambers were implanted sc in each of 12 calves. at 45 days after implantation, all tissue chambers were inoculated with an erythromycin-sensitive strain of p haemolytica. starting 24 hours after inoculation, calves were allotted to 4 groups of equal size and a 2 x 2-factorial arrangement of treatments was applied: 3 calves were give ...19921524293
pasteurella haemolytica a1 and bovine respiratory disease: pathogenesis.the severe fibrinonecrotic pneumonia associated with pneumonic pasteurellosis usually results from colonization of the lower respiratory tract by pasteurella haemolytica biotype a, serotype 1(a1). despite recent research efforts, the authors lack a detailed understanding of the interactions and host response to p. haemolytica in the respiratory tract. the authors hypothesize that management and environmental stress factors or viral infection alters the upper respiratory tract (urt) epithelium al ...19921548621
alveolar macrophage and neutrophil interactions in pasteurella haemolytica-induced endothelial cell injury.pasteurella haemolytica, the cause of fibrinous pleuropneumonia in cattle, produces extensive microvascular endothelial cell damage. this study investigated endothelial cell-leukocyte interactions by using a millicell coculture assay system that modeled the bovine pulmonary alveolar defense system and showed that p. haemolytica-mediated endothelial cell damage was enhanced by the presence of alveolar macrophages, presumably due to soluble alveolar macrophage products. the alveolar macrophage-enh ...19921552194
strain diversity within bovine pasteurella haemolytica serovar 2 respiratory tract isolates. 19921457554
systemic and pulmonary antibody responses of calves to pasteurella haemolytica after intrapulmonary inoculation.systemic and pulmonary antibody responses of calves to pasteurella haemolytica were evaluated by measuring immunoglobulin production in blood for 9 days and in pulmonary lavage fluid for 7 days after intrapulmonary inoculation. clinical signs, pulmonary lesions, pulmonary and systemic inflammatory response, and amount of antigen in lavage fluid were used to evaluate the response of calves to challenge with p haemolytica. the pulmonary response consisted of production of igg, ige, and igm antibod ...19921456537
the effect of the intra-mammary inoculation of lactating ewes with pasteurella haemolytica isolates from different sources.lactating welsh mountain ewes were inoculated, 3 weeks after lambing, with between 1000 and 10,000 colony forming units of a number of isolates of pasteurella haemolytica. isolates from severe, acute mastitis in a ewe, from ovine and bovine pneumonic lesions and from the nasal cavity of healthy lambs, all gave rise to severe, acute mastitis that was clinically indistinguishable from that seen naturally. two isolates from the milk of ewes with subclinical mastitis did not cause clinical disease a ...19921556261
[the significance of antibodies to pasteurella haemolytica a1 in the colostrum of cows and blood serum of calves].antibodies to p. haemolytica were detected in colostral sera of cows and blood sera of calves by means of indirect haemagglutination (iha) and elisa. the elisa titres of the colostral sera of the dams and of the blood sera of the calves showed a significantly positive correlation. there is a positive correlation between the titres of the two serological methods. the results of the challenge infection with p. haemolytica a 1 do not show a correlation between the titres and the severity of the dis ...19921575671
immune responses of lambs experimentally infected with bovine respiratory syncytial virus and pasteurella haemolytica.the immune responses of lambs experimentally infected with bovine respiratory syncytial virus (rsv) and pasteurella haemolytica were compared with lambs infected with bovine rsv or pasteurella haemolytica alone. superinfection with p. haemolytica aggravated the reduction in the number of cd5+, cd4+ and lca p220+ (b) lymphocytes caused by bovine rsv, but it had no effect on the neutralizing antibodies against p. haemolytica cytotoxin. serum samples obtained from lambs experimentally infected with ...19911779037
comparison of antigens of pasteurella haemolytica serotype 1 grown in vitro and in vivo.to determine whether antigenic differences exist in pasteurella haemolytica serotype 1 grown in different culture conditions, the bacteria was grown on solid enriched medium, in broth culture, and in tissue chambers subcutaneously implanted in the flanks of calves. the organisms obtained by each culture method were comparable with respect to encapsulation and lipopolysaccharide content. in the bacteria grown in vivo, several unique high molecular-mass (greater than 150 kda) protein antigens were ...19921586014
activation of bovine neutrophils by pasteurella haemolytica leukotoxin is calcium dependent.in this study, we used the fluorescent probe fluo-3 to show that an increase in cytosolic free calcium, [ca2+]i, occurred when suspensions of bovine neutrophils were incubated with sublethal concentrations of p. haemolytica leukotoxin. this increase in [ca2+]i was dependent on the concentration of leukotoxin present in the medium and, at a given concentration of leukotoxin, dependent on the external calcium concentration. the calcium channel blocker verapamil and the beta-adrenergic antagonist p ...19921431567
effects of pasteurella haemolytica leukotoxic culture supernatant on bovine neutrophil aggregation.pasteurella haemolytica a1 leukotoxic culture supernatant was evaluated for its ability to cause aggregation of bovine peripheral neutrophils. neutrophils were isolated by a hypotonic lysis method and incubated with zymosan-activated plasma (zap), leukotoxic culture supernatant, antileukotoxin serum, calcium and magnesium-free media, p-bromophenacyl bromide and protein kinase c inhibitors. aggregation was evaluated by changes in infrared light transmittance. leukotoxic culture supernatant caused ...19921423054
colonization of the tonsils of calves with pasteurella haemolytica.tonsils of 10 calves were inoculated with pasteurella haemolytica (ph) and the degree of colonization was followed by collecting sequential tonsil. wash specimens. tonsils were colonized for at least 3 weeks after instillation of ph into the tonsillar sinus. calves with colonized tonsils responded with serum and nasal secretion antibody responses to ph and to leukotoxin. pasteurella haemolytica was detected in nasal mucus specimens of 2 calves during the week after inoculation of the tonsils, bu ...19921586016
pulmonary immunity in calves following stimulation of the gut-associated lymphatic tissue by bacterial exotoxin.antibodies in serum and pulmonary lavage fluids were measured in calves following stimulation of the gut-associated lymphatic tissue (galt) by inoculation of crude leukotoxin of pasteurella haemolytica into the duodenum through a surgically placed catheter. nine calves free of p. haemolytica were divided into two groups. group 1 received an intraduodenal (id) inoculation of leukotoxin and group 2 received an id inoculation of phosphate buffered saline. serum and pulmonary lavage fluids were coll ...19921591657
the effect of inoculation of pasteurella haemolytica into the lactating mammary gland of mice, rats, rabbits, sows and cows.an isolate of pasteurella haemolytica (a9), which consistently produced severe mastitis in ewes, was inoculated into the lactating mammary glands of a variety of species. mastitis did not develop after the inoculation of log-phase bacteria into the mammary gland of lactating mice, rats, rabbits or sows but did so in the mammary gland of two cows. another a9 isolate from a ewe with mastitis and an a1 isolate from a bovine pneumonic lung also induced mastitis in cows. thus, in this study, p. haemo ...19921602056
interaction of ruminant transferrins with transferrin receptors in bovine isolates of pasteurella haemolytica and haemophilus somnus.the interactions of ruminant transferrins with receptors on bovine isolates of pasteurella haemolytica and haemophilus somnus were compared by growth studies and direct and competitive binding assays. isolates of p. haemolytica were capable of utilizing and binding transferrin from sheep, goat, or cattle, whereas isolates of h. somnus were capable of utilizing and binding only bovine transferrin.19921612764
characterization of lipopolysaccharides from four pasteurella haemolytica serotype strains: evidence for presence of sialic acid in serotypes 1 and 5.highly purified lipopolysaccharides (lps) obtained from four strains of pasteurella haemolytica representative of four different serotypes were studied to ascertain their overall structural elements and sugar and fatty acid compositions. sds-page analysis revealed that each lps was of the smooth-type although they differed in migration patterns. somewhat unusual features of these lps included the presence of: (a) rhamnose in the core oligosaccharides of serotypes 2 and 3; and (b) sialic acid in ...19921624117
[results of experimental immunization of calves with different pasteurella antigens].calves immunised with different pasteurella antigens (inactivated whole cells, sodium chloride extract) where challenged two weeks after the second immunization with the homologous strain. the intracutaneous application of whole cells of p. haemolytica a1 and p. multocida a was effective. the incidence of pneumonia was reduced and the pneumonic lesions were less severe. the sodium chloride extract was not effective.19921638965
outer-membrane protein and lipopolysaccharide variation in pasteurella haemolytica serotype a1 under different growth conditions.growth characteristics, as well as outer-membrane protein (omp) and lipopolysaccharide (lps) profiles in sds-polyacrylamide gels, of two serotype a1 isolates of pasteurella haemolytica were examined under different in vitro growth conditions. the two isolates were chosen as representatives of disease (s/c 82/1) and non-disease (w/d 83/4) isolates, respectively. the growth rates and final cell densities of both isolates increased as the degree of aeration increased. in particular, the final cell ...19921645128
pasteurella haemolytica infection in a goeldie's monkey.an adult male callimico goeldii died spontaneously. at necropsy, small whitish foci were found randomly distributed on the liver surface. histologically, the foci were composed of mixed inflammatory cells with predominant polymorphonuclear cell infiltration and central areas of necrosis. microbiological cultures revealed a gram-negative coccoid-bacilli with bipolar staining. biochemical analysis revealed that the microorganism was pasteurella haemolytica.19921307760
clinical pharmacokinetics of parenterally administered danofloxacin in cattle.danofloxacin is a new fluoroquinolone antibacterial, developed specifically for veterinary use. its in vitro activity and pharmacokinetic properties have been investigated to assess its potential for use in the therapy of respiratory disease in cattle. the minimum inhibitory concentration of danofloxacin against 90% (mic90) of contemporary european and north american field isolates of pasteurella haemolytica, pasteurella multocida and haemophilus somnus, the most important bacterial respiratory ...19911663562
protective effect of inactivated bovine herpesvirus-1 in calves experimentally infected with bovine herpesvirus-1 and pasteurella haemolytica.the protective effect of an inactivated whole-virion bovine herpesvirus-1 (bhv-1) immunising inoculum, without adjuvant, against viral-bacterial respiratory disease was studied in three experimental treatment groups of five calves each. one group was boosted 14 days after the first vaccination and at this time the second group received their initial inoculation. seven days later, calves were challenged with bhv-1 in aerosol and four days after this challenge all calves were exposed to pasteurell ...19911664970
separable domains define target cell specificities of an rtx hemolysin from actinobacillus pleuropneumoniae.the leukotoxin (lkta) from pasteurella haemolytica and the hemolysin (appa) from actinobacillus pleuropneumoniae are members of a highly conserved family of cytolytic proteins produced by gram-negative bacteria. despite the extensive homology between these gene products, lkta is specific for ruminant leukocytes while appa, like other hemolysins, lyses erythrocytes and a variety of nucleated cells, including ruminant leukocytes. both proteins require activation facilitated by the product of an ac ...19921729215
molecular chimerization of pasteurella haemolytica leukotoxin to interleukin-2: effects on cytokine and antigen function.a chimeric recombinant protein composed of the lkta gene product from pasteurella haemolytica fused to bovine interleukin-2 (il-2) was made. the lkt-il-2 chimera was compared with recombinant bovine il-2 with regard to the ability to induce proliferative responses and lak cell activity in bovine peripheral blood mononuclear cells in vitro. in both instances, chimerization had no effect on il-2 activity. similarly, the lkt component was unaffected in its ability to induce an effective immune resp ...19921730490
[pasteurella haemolytica serotypes in cattle].eight-two bovine pasteurella haemolytica strains were serotyped. the majority of the strains were isolated from calves which had died from fibrinous pneumonia and small numbers from cases of pleuritis, sepsis and abortion. a total of eight different serotypes were noticed. serotype a1 was found to be the most prevalent 37.8 per cent, followed by serotype a2 with 20.7 per cent. antibiotic resistance was found for sulfonamide, tetracycline and penicillin in about half of all strains. conventional ...19921733033
neutralizing monoclonal antibodies to pasteurella haemolytica leukotoxin affinity-purify the toxin from crude culture supernatants.the leukotoxin of pasteurella haemolytica is a major virulence factor of the organism. it is an unstable protein which has proven very difficult to purify using traditional techniques. hybridomas secreting monoclonal antibodies (mabs) to p. haemolytica leukotoxin were derived from spleen cells of a mouse immunized with crude culture supernatant. five hybridomas secreting mabs specific for the leukotoxin were stabilized. each of the mabs reacted with a protein of approximately 100 kda in toxic cu ...19911753879
spontaneous pasteurellosis in captive rocky mountain bighorn sheep (ovis canadensis canadensis): clinical, laboratory, and epizootiological observations.we observed clinical signs, compared adrenal responses, and performed diagnostic tests on 12 captive rocky mountain bighorn sheep (ovis canadensis canadensis) during a spontaneous outbreak of pasteurellosis. cortisol in urine and feces was measured for bighorns sampled three times between 20 october and 1 november 1986. by 6 november, four of these had developed pneumonia, four showed only mild rhinitis, and four remained clinically normal. bighorns that ultimately developed pneumonia showed ele ...19911758018
association of a pasteurella haemolytica-like organism with enteritis in swine.a pasteurella haemolytica-like organism was isolated from the intestines of 28 swine with clinical, gross, or microscopic evidence of enteritis. in 15 cases, other known enteric pathogens were also demonstrated, and in 13 cases, no other pathogens were detected. the mean age of affected animals was 44 days. most of the animals had clinical evidence of diarrhea. gross enteric lesions were present in 17 of 21 cases. microscopic lesions were present in 24 of 26 cases. a diffuse or segmental moderat ...19911760465
the experimental production of mastitis in sheep by intramammary inoculation of pasteurella haemolytica.acute mastitis was consistently produced in primiparous ewes by inoculation of the mammary gland, via the teat canal, with an isolate of pasteurella haemolytica, serotype a9, originating from a field case of ovine mastitis. mastitis developed following the inoculation of as few as 10 colony forming units of this isolate, suggesting that only a small number of organisms would be required to initiate the disease under natural conditions provided they were already beyond the teat canal. clinical si ...19911770180
experimental infection of dexamethasone-treated goats with pasteurella haemolytica a2.sixteen goats either subjected to transport stress or without transport stress were treated with dexamethasone for 3 days prior to infection with p. haemolytica serotype a2 intranasally. the transport-stressed and dexamethasone-treated goats in the first group had various degrees of pulmonary lesions and the organism was re-isolated from the nasal cavity, lymph nodes and lungs. none of the goats treated with dexamethasone only were infected with p. haemolytica and had no lesions of pneumonic pas ...19911777800
optimal conditions for the analysis of pasteurella haemolytica lipopolysaccharide by sodium dodecyl sulphate-polyacrylamide gel electrophoresis.the optimal conditions for the analysis of the lipopolysaccharide (lps) of two serotype a1 isolates and a serotype a2 isolate of pasteurella haemolytica by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (sds-page) and silver staining were determined. the lps of the a1 isolates possessed o side chains, consisting of high molecular mass bands with the appearance of a ladder-like pattern, as well as a low molecular mass core-oligosaccharide region; the lps of the a2 isolate consisted on ...19911783278
effect of pasteurella haemolytica saline capsular extract on bovine pulmonary endothelial cells.the purpose of this in vitro study was to determine whether pasteurella haemolytica capsular extract (ce) damages bovine pulmonary endothelial cells (ec) directly or through neutrophil-mediated mechanisms. chromium 51-labeled ec were treated with the following variables: ce (1, 10, and 100 ng of protein/ml), ce and bovine neutrophils (10(6) cells/well), and ce and polymyxin b (500 u/ml). although only minimal damage to ec occurred by 5 hours after treatment, by 22 hours after treatment, the 10-n ...19911785721
market stress-associated changes in serum complement activity in feeder calves.classical hemolytic complement (c) of calves was analyzed during a protocol designed to imitate the usual market handling of feeder calves from the southeastern united states. serum c concentrations of the calves (n = 100 x 4 years) were evaluated on their farm of origin, on arrival at an auction market, on arrival at a feedyard, and during their first 4 weeks in the feedyard. complement concentrations (measured in ch50 units) were typically lowest at the farm of origin and highest when the calv ...19911785726
occurrence and diversity of plasmids in ovine isolates of pasteurella haemolytica.160 ovine isolates of pasteurella haemolytica, representing each of the 16 serotypes and also untypable strains, were examined for plasmid content. plasmid dna was identified in, and prepared from, strains of serotypes a2, t3, a14 and a16 and also from an untypable strain. the relationship between the plasmids present in the different strains was examined both by restriction fragment profile analysis and by dna/dna hybridisation. both methods gave broadly similar results and showed that each ser ...19911788485
genomic distribution of a serotype 1-specific antigen-coding dna fragment of pasteurella haemolytica.a genomic fragment of pasteurella haemolytica biotype a coding for a serotype 1-specific agglutinating antigen was used as a probe in a series of hybridization experiments to determine distribution of the fragment in various p. haemolytica serotypes as well as other bacteria. results showed presence of the fragment in seven out of the 12 serotypes tested, all of which belonged to biotype a. two other serotypes belonging to biotype a, all three serotypes belonging to biotype t, two pasteurella mu ...19911789017
characterization and comparison of antimicrobial susceptibilities and outer membrane protein and plasmid dna profiles of pasteurella haemolytica and certain other members of the genus pasteurella.the outer membrane protein (omp), plasmid, and antimicrobial resistance profiles of pasteurella haemolytica serotypes 1 through 12, a bovine isolate of p multocida, a chicken isolate of p multocida, and an unidentified pasteurella species of bovine origin were examined. isolates of p haemolytica serotypes belonging to the same biotype possessed similar omp profiles. biotype a isolates contained 2 prominent omp of 43 kilodaltons (kd) and 29 kd, whereas biotype-t serotypes contained 3 major omp of ...19911789515
the microbial flora of the respiratory tract in feedlot calves: associations between nasopharyngeal and bronchoalveolar lavage cultures.the upper and lower respiratory tracts of 59 feedlot calves with clinical signs of naturally occurring respiratory disease (cases) and 60 comparison (control) animals were cultured before treatment, using nasopharyngeal swabs (nps) and bronchoalveolar lavage (bal). the most prevalent organisms were pasteurella multocida and mycoplasma bovis. isolations of p. multocida from nps and bal fluid were found to be significantly associated with morbidity (p less than or equal to 0.05), but the frequency ...19911790489
in vivo expression of iron regulated outer-membrane proteins in pasteurella haemolytica-a1.pasteurella haemolytica-a1 was grown in vitro under iron-rich conditions, iron-depleted conditions, and in vivo within a chamber implanted in the peritoneal cavity of a rabbit to determine if iron regulated outer-membrane proteins were expressed in vivo. the antigenicity of outer membrane (om) proteins from bacteria grown under these conditions was assessed by immunoblotting with pooled serum from convalescent bovine calves experimentally infected with p. haemolytica-a1 and serum from the implan ...19911816491
characterisation and biological activity of monoclonal antibodies specific for pasteurella haemolytica a1 capsule and lipopolysaccharide.monoclonal antibodies (mab) against both pasteurella haemolytica a1 capsule and lipopolysaccharide (lps) were produced. anti-capsule mab reacted with the homologous a1 serotype only, whereas mab against lps reacted with p. haemolytica serotypes a2, a5, a8, a12, a14 and a16 but not with 33 bacterial species or rough lps mutant strains tested. both capsule and lps antigens were visualised on the surface of bacteria by immunogold electron microscopy. neither of the mabs demonstrated antibody-depend ...19921626366
exposure of sheep to pasteurella haemolytica alters ex vivo pulmonary vascular smooth muscle alpha adrenergic responses: role of vascular endothelium.sheep were exposed to a live- vaccine derived strain of pasteurella haemolytica (10(5) colony forming units/sheep, i.m.) and euthanized 3 days later. pulmonary artery and vein ex vivo responses to cumulative doses of methoxamine were determined. in some experiments endothelium was removed. in the pulmonary artery, removal of the endothelium significantly impairs the potency of methoxamine as a contractile agent in control sheep. also, in sheep exposed to p. haemolytica removal of the endothelium ...19911666196
a neutral glycoprotease of pasteurella haemolytica a1 specifically cleaves o-sialoglycoproteins.a neutral metalloprotease with marked specificity for an o-sialoglycoprotein has been isolated from culture supernatants of pasteurella haemolytica a1. the 35-kda enzyme cleaves human erythrocyte glycophorin a, which is o glycosylated, but does not cleave n-glycosylated proteins or nonglycosylated proteins. glycophorin a was cleaved when it was present in situ in erythrocyte ghost plasma membranes or when it was free in solution. the glycoprotease did not hydrolyze glycophorin a from which siala ...19921729196
alterations in pulmonary morphology and peripheral coagulation profiles caused by intratracheal inoculation of live and ultraviolet light-killed pasteurella haemolytica a1 in calves.eighteen male holstein calves were divided into groups of three and inoculated intratracheally with 5 x 10(9) logarithmic phase or ultraviolet light-killed pasteurella haemolytica biotype a serotype 1. serial coagulation profiles were done on one calf from each group during the first 24 hours after inoculation. one calf from each group was necropsied at 4, 12, and 24 hours after inoculation and lesions were characterized with light and transmission electron microscopy. we found that 1) the pulmo ...19911949506
the effect of pasteurella haemolytica a1 leukotoxic culture supernate on the in vitro proliferative response of bovine lymphocytes.the effect of sublethal concentrations of the pasteurella haemolytica leukotoxic culture supernate on bovine lymphocyte blastogenesis was investigated. blastogenesis in cultures stimulated with either concanavalin a (con a) or pokeweed mitogen (pwm) was inhibited in the presence of the supernate, as was the response to purified protein derivative in lymphocytes from bcg-vaccinated cattle. partially purified leukotoxin had a similar effect. pre-incubation of the leukotoxic supernate with a polycl ...19911949582
effect of recombinant bovine interleukin-1 beta on viral/bacterial pneumonia in cattle.bovine herpesvirus-1 (bhv-1) is an important pathogen of respiratory infections in cattle. its continuing importance lies in its ability to predispose infected hosts to bacterial infections (e.g., pasteurella haemolytica). in this study we determined whether the immunoregulatory effects induced by recombinant bovine interleukin-1 (rbil-1) could stimulate appropriate host defense mechanisms to influence the course of bhv-1 and p. haemolytica infection in cattle. we first evaluated the effect of m ...19957648445
preliminary investigation of the mechanism of inhibition of bovine lymphocyte proliferation by pasteurella haemolytica a1 leukotoxin.pasteurella haemolytica a1 leukotoxic culture supernate has been shown to inhibit bovine lymphocyte blastogenesis induced by concanavalin a (con a), pokeweed mitogen (pwm) and purified protein derivative (ppd). the various mechanisms by which this inhibition could be overcome were investigated in an effort to determine at which stage of cell activation the leukotoxin exerted its inhibitory effect. for both con a and pwm stimulated cultures, the addition of partially purified bovine interleukin 1 ...19911949583
o-sialoglycoprotease from pasteurella haemolytica. 19957674959
partial characterization of the leukotoxin of pasteurella haemolytica-like bacteria isolated from swine enteritis.pasteurella haemolytica-like (phl) strains isolated from diarrheic pigs are known to produce a leukotoxin that is lethal to ruminant leukocytes. in the present study, 12 phl strains were screened for leukotoxin production using a tetrazolium dye-reduction assay. sterile culture supernatant from strain 6213a, the maximum leukotoxin producer, was used as the crude leukotoxin for characterization studies. the leukotoxin was inactivated by heat at 60 degrees c and by trypsin, protease, and amylase. ...19957483245
functional analysis of the bacillus subtilis purt gene encoding formate-dependent glycinamide ribonucleotide transformylase.the purt gene from bacillus subtilis encoding the formate-dependent glycinamide ribonucleotide transformylase t was cloned by functional complementation of an escherichia coli purn purt double mutant. the nucleotide sequence revealed an open reading frame of 384 amino acids. the purt amino acid sequence showed similarity to the enzyme phosphoribosylaminoimidazole carboxylase encoded by the purk gene but not to the n10-formyltetrahydrofolate-dependent glycinamide ribonucleotide transformylase n e ...19957496533
evaluation of different methods for the detection of outer membrane proteins and lipopolysaccharides of pasteurella haemolytica by immunoblotting.the optimal conditions for the detection of outer membrane proteins (omps) and lipopolysaccharide (lps) of pasteurella haemolytica by immunoblotting were evaluated. the variables examined included the equilibration time of the gels before transfer, composition of the transfer buffer, type of blotting membrane, blocking agent, effect of the zwitterionic detergent empigen bb on protein renaturation, and the development reagent. the composition of the transfer buffer and time of gel equilibration s ...19947508480
pasteurella haemolytica leukotoxin induces histamine release from bovine pulmonary mast cells.pasteurella haemolytica a1 leukotoxic culture supernatant was evaluated for its ability to induce histamine release from bovine pulmonary mast cells isolated by enzymatic dispersion of lung tissue. histamine was measured by a radioimmunoassay technique. leukotoxic culture supernatant of p. haemolytica significantly released histamine in a time and concentration-related manner. this effect was lost when culture supernatant was heat-inactivated or preincubated with leukotoxin neutralizing rabbit s ...19947511483
fetuin is a substrate for pasteurella haemolytica o-sialoglycoprotease.a soluble bovine glycoprotein, fetuin, was used as an alternative substrate to identify o-sialoglycoprotease activity in culture supernatant protein fractions of pasteurella haemolytica. an aliquot of a 24-hour incubation mixture containing fetuin and o-sialoglycoprotease was denatured and examined after gradient sodium dodecyl polyacrylamide gel electrophoresis. the coomassie-brilliant-blue-stained gel was examined for the disappearance of the fetuin band at an apparent molecular mass of 64 kda ...19957542891
chaotropic agents cause disaggregation and enhanced activity of pasteurella haemolytica leukotoxin.pasteurella haemolytica biotype a, serotype 1 grown to late logarithmic growth phase in cell culture medium (rpmi 1640) produced highly aggregated leukotoxin. the multimer mass of the highly aggregated leukotoxin in 0.1 m sodium phosphate buffer ph 7.0 as determined by gel filtration chromatography on sephacryl s400hr was approximately 8000 kda. resuspension of leukotoxin in phosphate buffer containing various chaotropic agents resulted in partial disaggregation of leukotoxin and enhanced leukot ...19957571371
an in vitro model system to evaluate pulmonary macrophage, endothelial cell, and neutrophil interactions.pasteurella haemolytica, the cause of fibrinous pleuropneumonia in cattle, produces extensive microvascular endothelial cell (ec) damage. we have developed an in vitro model system to study the inflammatory process of this disease involving the interaction of pulmonary alveolar macrophages (am), neutrophils (pmn), and ec. bovine ec are grown to confluency in 24 well tissue culture plates. to mimic the vascular component, 10(6) pmn are later added to the ec monolayers. bovine am are plated onto m ...19911793029
isolation of pasteurella haemolytica from the nasal cavity of goats.twenty transport-stressed goats were divided into two groups. the first group was further stressed with steroid. pasteurella haemolytica was found at various sites in the nasal cavity of goats in this group as early as 2 weeks post-transportation. the successful isolations continued consistently with more goats having pure growth of p. haemolytica at later stages. mild catarrh rhinitis, loss of epithelial cilia and erosions were the main lesions observed in the nasal cavity. goats in the second ...19911913132
effects of experimentally induced pasteurella haemolytica infection in dairy calves on the pharmacokinetics of flumequine.the effect of experimental pasteurella haemolytica infection on the intravenous and intramuscular pharmacokinetics of flumequine was studied in dairy calves. the plasma concentration-time curve of flumequine after intravenous injection of 5 mg/kg bodyweight flumequine of a 10% solution before and after experimental infection, was best described by a three-compartment open model. after intramuscular injection of the same dosage rate of a 3% flumequine suspension is was best described by the one-c ...19911920605
comparison of four immune variables and pulmonary lesions of goats with intrapulmonary exposure and subsequent intrathoracic challenge exposure with pasteurella haemolytica.a comparison of immune variables following lung sensitization with live pasteurella haemolytica serotype 1 (ph1)-impregnated agar beads was done in 2 separate trials. the ph1 immune variables studied were blood bactericidal activity, serum bacteriolysis, total classical complement, and indirect hemagglutination antibody. each trial had 16 male weanling goats: 6 controls and 10 principals. in trial 1, each goat was surgically catheterized through the trachea, then the material was deposited in a ...19911928902
[clinical, diagnostic laboratory and therapeutic studies of mastitis in a large sheep breeding flock].during two lambing seasons, 6500 ewes of a large sheep breeding unit were investigated. within this period, 467 ewes suffered from mastitis. the morbidity was 3.8% and the lethality 4.7%. in 84% of the investigated animals udder-pathogenic bacteria were detected. mostly, pasteurella haemolytica and staphylococcus aureus were isolated as agents of ovine mastitis. before and during the antibiotic therapy the clinical symptoms (general condition, temperature, milk appearance, consistency of the udd ...19947716748
identification of rtx toxin target cell specificity domains by use of hybrid genes.the escherichia coli hemolysin (hlya) and pasteurella haemolytica leukotoxin (lkta) are cytolytic toxins encoded by genes belonging to the recently described rtx gene family. these cytotoxins are, respectively, 1,023 and 953 amino acids in length and are encoded by genes within identically organized operons. they share 45% amino acid sequence identities but differ in their target cell specificities. in vitro-derived recombinant hybrid genes between hlya and lkta were constructed by using restric ...19911937778
protective role of bovine neutrophils in pasteurella haemolytica-mediated endothelial cell damage.the purpose of this study was to determine if pasteurella haemolytica can directly injure bovine pulmonary endothelial cells (ec) and if neutrophils have a beneficial or detrimental role in bacterium-ec interaction. various combinations of live p. haemolytica, heat-killed p. haemolytica, anti-p. haemolytica immune serum, polymyxin b, and bovine neutrophils were added to confluent monolayers of bovine ec. monitoring included determination of 51cr release from ec, phase microscopy, and transmissio ...19911937816
pasteurella haemolytica lipopolysaccharide-associated protein induces pulmonary inflammation after bronchoscopic deposition in calves and sheep.the lipopolysaccharide (lps)-associated protein (lap) was extracted from pasteurella haemolytica serotype a1 strains l101 (bovine origin) and 82-25 (ovine origin). extracts contained 0.017% total lps and appeared as only two bands at 14 and 16.6 kda after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. to determine the extent of pulmonary inflammation induced by lap and its possible role in the pathogenesis of pneumonic pasteurellosis, lap (500 micrograms in pyrogen-free saline [pfs]) ...19957642296
dissociation of cytolysis and monokine release by bovine mononuclear phagocytes incubated with pasteurella haemolytica partially purified leukotoxin and lipopolysaccharide.the bovine respiratory pathogen pasteurella haemolytica secretes an exotoxin that is specific for ruminant leukocytes (leukotoxin). previous studies have shown that subcytolytic concentrations of the leukotoxin stimulate bovine neutrophils to undergo a respiratory burst and degranulate. relatively little is known about the stimulatory effects of the leukotoxin on bovine mononuclear phagocytes. in this study, we compared the relative cytolytic effects of partially purified leukotoxin on bovine pe ...19957648522
evaluation of combined pasteurella vaccines in control of sheep pneumonia.the effectiveness of an oil adjuvant vaccine (oav) incorporating locally isolated strains of pasteurella haemolytica type 7 and pasteurella multocida types a and d was compared with that of carovax (wellcome laboratories) in imported cross-bred lambs. the criterion of efficacy was the ability of the vaccines to reduce the extent of pneumonic lesions in vaccinated as against unvaccinated control lambs. the oav produced at this institute significantly reduced the lung lesions at p less than 0.05 l ...19911959015
purified pasteurella haemolytica leukotoxin induces expression of inflammatory cytokines from bovine alveolar macrophages.we obtained biologically active purified leukotoxin (lkt) from pasteurella haemolytica serotypel, strain 12296 using preparative sodium dodecyl sulfate polyacrylamide gel electrophoresis (sds-page). three species of lkt of molecular masses 95, 100, and 104 kda were obtained. purity of all three species of lkt was confirmed by analytical sds-page and western blot (immunoblot) analysis. results from the chromogenic limulus amebocyte lysate assay and silver staining of sds-page patterns indicated t ...19957476090
purification of a pasteurella haemolytica serotype 1-specific polysaccharide epitope by use of monoclonal antibody immunoaffinity.a murine igm monoclonal antibody causing bacterial agglutination was used in an immunoaffinity procedure to purify a serotype 1-specific polysaccharide epitope from pasteurella haemolytica. the p haemolytica serotype 1-specific antibody was precipitated from peritoneal ascitic fluid, dialyzed, and covalently attached to cyanogen bromide-activated sepharose 4b beads. retention of purified antibody activity and coupling efficiency were > 99% when evaluated by elisa, agglutination testing, and prot ...19937686355
restriction endonuclease analysis and ribotyping differentiate pasteurella haemolytica serotype a1 isolates from cattle within a feedlot.pasteurella haemolytica serotype a1 isolates were collected from cattle within a feedlot during an outbreak of bovine respiratory disease. genetic heterogeneity among the isolates was examined by restriction endonuclease analysis (rea), ribotyping, and analysis of plasmid content. the susceptibilities of isolates to several antibiotics were also examined. five different rea patterns and three different ribotypes were observed among the isolates. fifty percent of the isolates had an identical rea ...19937691872
expression, purification and immunologic analysis of three pasteurella haemolytica a1 28-30 kda lipoproteins.three genes, tandemly arranged on the pasteurella haemolytica a1 chromosome and encoding similar 28-30 kda proteins, were previously cloned and sequenced by our laboratory. in this study, we demonstrate that the cloned genes encode lipoproteins, as previously suggested by dna sequence analysis. to further analyze the bovine immune response to these proteins, the individual genes were cloned separately into an expression vector and recombinant forms of the three proteins were purified after expre ...19947700132
the role of eicosanoids in the chemotactic response to pasteurella haemolytica infection.the chemotactic role of eicosanoids in the pathogenesis of pasteurella haemolytica infection was studied, using a tissue chamber infection model and pharmacological inhibitors of eicosanoid synthesis. tissue chambers were implanted subcutaneously in 12 calves allotted to three treatment groups of equal size. at 45 days after implantation, calves received saline, dexamethasone, or phenylbutazone treatments, and tissue chambers in all animals were then inoculated with p. haemolytica. chamber fluid ...19947701861
colonization of the tonsils and nasopharynx of calves by a rifampicin-resistant pasteurella haemolytica and its inhibition by vaccination.a rifampicin-resistant pasteurella haemolytica serotype 1 with 2 added plasmids was used as a colonization-challenge strain in calves to test the resistance to colonization elicited by vaccination. nine calves were vaccinated with a tissue culture-derived p haemolytica serotype-1 vaccine which, in a prior study, had elicited a serotype-specific inhibition of nasal and tonsillar colonization by the homologous serotype under field conditions. the vaccinates and 9 nonvaccinated control calves were ...19957574152
isolation and partial characterization of the major protein of the outer membrane of pasteurella haemolytica and pasteurella multocida.the n-terminal amino acid sequence of the 35 kda (p35) major outer membrane protein (momp) of p. multocida shared a strong homology with those of homotrimeric nonspecific porins of gram-negative bacteria. the capacity of outer membrane protein (omp) preparations of p. multocida to bind to respiratory mucosal surface preparations was inhibited significantly by using a polyclonal anti-p35 antiserum in an adhesion elisa. anti-p35 antiserum cross-reacted with a 44 kda (p44) momp of p. haemolytica. n ...19947803929
vaccination of cattle with outer membrane protein-enriched fractions of pasteurella haemolytica and resistance against experimental challenge exposure.administration of an n-lauroylsarcosine-derived outer membrane protein fraction of pasteurella haemolytica a1 (sci-1) induced a protective response in calves against intrathoracic challenge exposure with the homologous serovar. outer membrane proteins from heterologous serovars, a6 and a9, induced partial protection that was associated with their respective similarities to serovar a1 in outer membrane protein profiles derived by use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. c ...19957574154
sequence analysis of leukotoxin secretion determinants from a pasteurella haemolytica-like organism.the phlbd genes encoding the secretion functions for the 105 kda rtx leukotoxin of pasteurella haemolytica-like (phl) organism has been cloned and sequenced. like analogous genes from other rtx determinants, the phlbd genes lie immediately downstream from the leukotoxin structural gene, phla. although isolated from a diverse group of gram-negative organisms, the phlbd genes and the characterized rtx bd genes from other organisms exhibit a high degree of homology at both the dna and predicted ami ...19957579583
extracellular neuraminidase production by pasteurella species isolated from infected animals.a total of 721 field isolates of various pasteurella species (haemolytica, multocida, and testudinis) from various regions of the united states were examined for extracellular neuraminidase production. all strains were grown and tested in the same way. included were 372 p. haemolytica serotype 1 isolates, 181 p. haemolytica serotype 2 isolates, 63 p. haemolytica serotype 6 isolates, 101 pasteurella multocida isolates, and 4 pasteurella testudinis isolates. all pasteurella species examined produc ...19957580802
effects of various vaccination protocols on passive and active immunity to pasteurella haemolytica and haemophilus somnus in beef calves.two field trials were conducted in a beef cow herd in saskatchewan to determine the effectiveness of a combined pasteurella haemolytica and haemophilus somnus vaccine in increasing passively and actively acquired antibodies in beef calves. vaccination of dams at 4 and/or 7 weeks prepartum was associated with increased antibody titers to p. haemolytica and h. somnus in their serum (p < 0.05), colostrum(p < 0.05), and serum of their calves at 3 days and 1 month of age (p < 0.05). there was no sign ...19957585417
proteasome sequences in eubacteria. 19947846763
isolation of pasteurella haemolytica leukotoxin mutants.two mutants of pasteurella haemolytica a1 that do not produce leukotoxin were isolated. following mutagenesis, colonies were screened with antiserum by a filter assay for absence of the secreted leukotoxin. the two mutants both appeared to produce normal amounts of other antigens, as judged by reactivity with polyclonal serum from an animal with pasteurellosis, and were not altered in beta-hemolytic activity as seen on blood agar plates. there was no evidence of either cell-associated or secrete ...19957868223
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