Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
serum antibody response to purified pasteurella haemolytica capsular polysaccharide in cattle.capsular polysaccharide (cp) of pasteurella haemolytica, biotype a, serotype 1, was purified and combined with saline solution, aluminum hydroxide, and freund's incomplete (oil) adjuvant. three groups of calves were administered the various antigen preparations. the cp in saline preparation was also administered to 5 mature cows. second injections were given 4 weeks after the first. weekly obtained serum samples were analyzed for p haemolytica-specific antibody, using the indirect hemagglutinati ...19938323052
analysis of tandem, multiple genes encoding 30-kda membrane proteins in pasteurella haemolytica a1.a number of outer membrane proteins (omps), including a 30-kda protein, may be important in eliciting immunity to pasteurella haemolytica a1, the causative agent of bovine pneumonic pasteurellosis. to better understand the nature of the 30-kda antigen, several genes encoding this protein were sequenced. sequence analysis revealed that three separate genes encoding similar, yet distinct, versions of the 30-kda protein are tandemly arranged on the p. haemolytica a1 chromosome. the genes appear to ...19938335249
distribution of intramuscularly administered erythromycin into subcutaneous tissue chambers before and after inoculation with pasteurella haemolytica.distribution of erythromycin into subcutaneous tissue chambers was characterised pharmacokinetically and the effect of pasteurella haemolytica infection on the extent of penetration was studied. thermoplastic tissue chambers were implanted subcutaneously in the paralumbar fossae of six calves. thirty-five days after implantation, the tissue chamber distribution of intramuscularly administered erythromycin (30 mg kg-1) was studied. chambers were then inoculated with p haemolytica and the tissue c ...19938337485
clinical and serological evaluation of a pasteurella haemolytica a1 capsular polysaccharide vaccine.the purified capsular polysaccharide (cps) of pasteurella haemolytica a1 was examined for its ability to protect cattle from experimental challenge with logarithmic-phase p. haemolytica. several preparations of p. haemolytica antigens were utilized in the experiment including cps, log-phase p. haemolytica culture supernatant, p. haemolytica recombinant leucotoxin (rlkt) and various combinations of the above. cps alone or in combination with culture supernatant or rlkt elicited no protection; rat ...19938342324
effects of pasteurella haemolytica culture supernate on bovine tracheal smooth muscle.pasteurella haemolytica leukotoxin is a ruminant specific leukotoxin that has been implicated in the pathogenesis of shipping fever in cattle. the present study was undertaken to determine the effect of this toxin on bovine airway smooth muscle. in vitro, the addition of culture supernate containing leukotoxin to bovine tracheal smooth muscle resulted in contraction of 55% of the muscle strips tested. maximum responses were reached rapidly during cumulative additions of this material. in 95% of ...19938358681
expression of the pasteurella haemolytica leukotoxin is inhibited by a locus that encodes an atp-binding cassette homolog.multicopy and single-copy chromosomal fusions between the pasteurella haemolytica leukotoxin regulatory region and the escherichia coli beta-galactosidase gene have been constructed. these fusions were used as reporters to identify and isolate regulators of leukotoxin expression from a p. haemolytica cosmid library. a cosmid clone, which inhibited leukotoxin expression from multicopy and single-copy protein fusions, was isolated and found to contain the complete leukotoxin gene cluster plus addi ...19938359916
the region of human transferrin involved in binding to bacterial transferrin receptors is localized in the c-lobe.iron-saturated human transferrin was digested with either chymotrypsin or trypsin to produce c-lobe and n-lobe protein fragments. individual protein fragments were purified by a combination of gel filtration and concanavalin a affinity chromatographic procedures. the c-lobe and n-lobe fragments of human transferrin were then used in binding assays to assess their ability in binding to the bacterial transferrin receptors. competitive binding assays demonstrated that the c-lobe fragment of human t ...19938361358
vaccine-derived pasteurella haemolytica alter the responses of ovine pulmonary artery and vein to drugs acting on adenylate cyclase.sheep were vaccinated with a live, vaccine-derived strain of pasteurella haemolytica. the ex vivo response of isolated pulmonary artery and vein to isoproterenol, cholera toxin, sodium fluoride and calcium were examined three days after vaccination. in the pulmonary artery (endothelium intact), vaccination did not alter the response to isoproterenol, or sodium fluoride whereas the relaxation response to cholera toxin was impaired. in the pulmonary artery (endothelium removed), the maximum relaxa ...19938378617
use of dna analysis of pasteurella haemolytica biotype t isolates to monitor transmission in bighorn sheep (ovis canadensis canadensis).pneumonia has been identified as a major cause of poor lamb survival in indigenous herds of rocky mountain bighorn sheep (ovis canadensis canadensis) in central idaho. pasteurella haemolytica was isolated from five adult rocky mountain bighorn ewes captured from a free-ranging herd in central idaho. the lambs from two of these ewes delivered by cesarean section were free of p. haemolytica until 40 days of age and after repeated contact with their dams. the lambs subsequently developed signs of p ...19938385150
vaccination with live pasteurella haemolytica alters vascular adrenergic reactivity.rats were injected with sterile saline (controls) or 0.7 x 10(5) c.f.u. of pasteurella haemolytica (biotype a) obtained from a commercial vaccine. three days following vaccination animals were killed and aortas removed from the heart base. isolated aorta was placed in a tissue bath and the biophysical responses to phenylephrine (alpha-1 agonist), clonidine (alpha-2 agonist) and isoproterenol (beta agonist) determined. the results indicate that the alpha-2 adrenergic contractile response to cloni ...19938386846
enhancement of neutrophil-mediated injury to bovine pulmonary endothelial cells by pasteurella haemolytica leukotoxin.in this study, we used an in vitro coculture system to determine which virulence factor from pasteurella haemolytica a1 was responsible for augmenting bovine polymorphonuclear neutrophil (pmn)-mediated killing of bovine pulmonary artery endothelial cells (bpaec). a 51cr release cytotoxicity assay was used as a measure of bpaec killing. the mechanisms associated with this bpaec killing were also studied. our results demonstrated that the leukotoxin and not the lipopolysaccharide from p. haemolyti ...19938388866
effect of copper deficiency on tissue, blood characteristics, and immune function of calves challenged with infectious bovine rhinotracheitis virus and pasteurella hemolytica.fourteen holstein steers, averaging 30 d of age, were fed a semipurified diet (1.5 mg of cu/kg) supplemented with 0 (-cu) or 10 mg of cu/kg of diet (+cu) for 5 mo. calves were then challenged by consecutive exposure to aerosol preparations of infectious bovine rhinotracheitis virus (ibrv) and pasteurella hemolytica on d 0 and 7, respectively, of the 30-d study. serum ceruloplasmin and plasma copper were higher in +cu calves throughout the challenge period and increased in +cu calves after microb ...19938389346
characterization of neuraminidases produced by various serotypes of pasteurella haemolytica.neuraminidases produced by 16 strains of pasteurella haemolytica (serotypes 1 to 16) were characterized by molecular weight, antigenic identity, and substrate specificity. after growth in a chemically defined medium, stage i (lyophilized) culture supernatants were assayed for activity with n-acetylneuramin lactose, human alpha-1-acid glycoprotein, fetuin, colominic acid, and bovine submaxillary mucin. neuraminidase produced by p. haemolytica serotype a1 (ph a1) was purified by a combination of s ...19938406865
three contiguous lipoprotein genes in pasteurella haemolytica a1 which are homologous to a lipoprotein gene in haemophilus influenzae type b.an escherichia coli clone carrying the recombinant plasmid pph24 has been found to express highly immunoreactive antigens of pasteurella haemolytica a1. two or three antigens of approximately 30 kda were located to both the inner and outer membranes of the e. coli clone and in p. haemolytica a1. from the insert dna of 8.2 kbp on pph24, a fragment of 4.6 kbp was found to code for these antigens. nucleotide sequence analysis of the 4.6-kbp dna identified three genes (designated plpa, -b, and -c) a ...19938406866
structural and serological specificities of pasteurella haemolytica lipopolysaccharides.lipopolysaccharides (lpss) from 16 serotypes of pasteurella haemolytica were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and examined by silver staining and immunoblotting. silver staining of proteinase k-digested cell lysates revealed two rough lps serotypes (serotypes 2 and 8), which lacked demonstrable o-polysaccharide, while 14 others demonstrated a ladder pattern characteristic of smooth-type lps. purified lpss from several serotypes yielded o-polysaccharide in ad ...19938418039
neuraminidase production by a pasteurella haemolytica a1 strain associated with bovine pneumonia.the properties of an extracellular neuroaminidase produced by a pasteurella haemolytica a1 strain (isolated from a case of bovine pneumonia) during growth in a defined medium were examined in this investigation. this enzyme, isolated from concentrated culture supernatants of p. haemolytica a1, was active against n-acetylneuramin lactose, human alpha 1-acid glycoprotein, fetuin, and bovine submaxillary mucin. neuraminidase production paralleled bacterial growth in a defined medium and was maximal ...19938418046
identification of pasteurella haemolytica a1 isolates from market-stressed feeder calves by use of enzyme and antimicrobial susceptibility profiles.an epidemiologic study of pasteurella haemolytica serovar 1 (ph1) in market-stressed feeder calves from 7 farms in eastern tennessee was conducted. the nasal mucus of each calf was cultured sequentially at the farm of origin (day 0), at an auction market (day 133), and at a feedyard in texas (days 141, 148, 155, and 169). of the 103 calves tested, 77 were culture-positive, including 1 on day 0, 1 on day 133, 20 on day 141, 57 on day 148, 50 on day 155, and 14 on day 169. from the 143 ph1 isolate ...19938427478
serum levels of tumor necrosis factor-alpha in calves experimentally infected with pasteurella haemolytica a1.the purpose of this study was to document the levels of tumor necrosis factor-alpha (tnf) in serum of calves experimentally infected intratracheally with pasteurella haemolytica a1 and to determine if elevated tnf levels correlate with development of pneumonic pasteurellosis in the bovine. serum samples were collected at sequential time periods from 0 h to 72 h post inoculation with p. haemolytica. tnf levels in those sera were measured by a cytotoxicity assay utilizing the tnf-sensitive wehi 16 ...19938430501
pasteurella haemolytica cytotoxin-dependent killing of neutrophils from bighorn and domestic sheep.peripheral blood neutrophils from rocky mountain bighorn sheep (ovis canadensis canadensis) and domestic sheep were exposed to culture supernatants from pasteurella haemolytica isolates recovered from these two sheep species. six culture supernatants from bighorn sheep isolates and two from domestic sheep isolates were tested for cytotoxicity as determined by the release of lactate dehydrogenase. two of the bacterial culture supernatants from bighorn sheep were not cytotoxic, while the other fou ...19938445788
classification, pathogenicity, and drug susceptibility of hemolytic gram-negative bacteria isolated from sick or dead chickens.fifteen hemolytic gram-negative bacteria were isolated from the respiratory tracts of sick birds suffering from a long-lasting respiratory syndrome or from the bone marrow of dead birds distributed in the southern part of taiwan. these were classified as pseudomonas aeruginosa (10 isolates), pseudomonas fluorescens (2 isolates), pseudomonas stutzeri (1 isolate), pasteurella haemolytica (1 isolate), and proteus morganii (1 isolate). each isolate was inoculated intraperitoneally into one group of ...19938452510
genomic fingerprinting of "haemophilus somnus" isolates by using a random-amplified polymorphic dna assay.the random-amplified polymorphic dna (rapd) assay was used to generate dna fingerprints for 16 isolates of "haemophilus somnus," and one isolate each of "haemophilus agni," "histophilus ovis," "actinobacillus seminis," pasteurella haemolytica, and escherichia coli. the rapd assay differentiated among "h. somnus" isolates, which shared similarity coefficients of 0.46 to 1.00 on the basis of pairwise comparisons of rapd markers produced with nine random decamer primers. three virulent encephalitic ...19938458944
further characterization of pasteurella haemolytica-like bacteria isolated from swine enteritis.dna-dna hybridization studies were conducted on six pasteurella haemolytica-like (phl) organisms recovered from cases of swine enteritis. chromosomal-enriched fractions of phl organisms served as the source of dna for southern blots or as whole-chromosomal dna probes. under stringent hybridization conditions, chromosomal dna probes of a prototype phl (strain 6213a) organism distinguished other phl organisms from pasteurella haemolytica types a1 and t3, pasteurella multiocida types a:1 and a:3, e ...19938460470
absence of circulating tnf alpha in experimental bovine pneumonic pasteurellosis. 19938470349
a review of the toxicology of the antibiotic micotil 300.micotil 300 is a new macrolide antibiotic for the treatment of bovine respiratory disease complex. as with other macrolides used in human and veterinary medicine, overdoses of micotil do not produce pathognomonic lesions. the toxicity dose response varies among laboratory animal and domestic livestock species. however, clinical evidence of micotil toxicity due to large doses is generally a manifestation of the positive chronotropic and negative inotropic cardiovascular effects. no adverse enviro ...19938470360
morphological and functional disturbances in pulmonary vascular endothelium following exposure of sheep to an "avirulent" strain of pasteurella haemolytica.sheep were vaccinated with a live attenuated strain of pasteurella haemolytica and killed 3 days later. segments of main intrapulmonic artery and vein were removed for biophysical and scanning electron microscopic studies. in the pulmonary artery, vaccination with pasteurella haemolytica caused an increase in the number of endothelial cell surface blebs and, in some cases, those blebs appeared to be splitting open, suggesting cell damage or irritation. there was a surprising lack of platelet adh ...19938473560
molecular characterization of a leukotoxin gene from a pasteurella haemolytica-like organism, encoding a new member of the rtx toxin family.a pasteurella haemolytica-like organism, a new species of bacterium isolated from piglets with diarrhea, secretes a leukotoxin into the culture media. western blot (immunoblot) analysis indicated that this leukotoxin cross-reacted with antileukotoxin antibody derived from cattle immunized with p. haemolytica. five overlapping recombinant bacteriophages carrying the gene for this 105-kda polypeptide were identified with a dna probe containing sequences from the p. haemolytica lktca genes from a p ...19938478098
functional replacement of the hemolysin a transport signal by a different primary sequence.secretion of the 107-kda hemolysin a (hlya) from escherichia coli is mediated by the membrane proteins hemolysin b and hemolysin d. hemolysin b is a member of the so-called atp binding cassette transporter superfamily, which includes the multidrug resistance p-glycoprotein, the cystic fibrosis cftr protein, and the major histocompatibility complex-associated transporter of antigenic peptides. recognition of hlya by the hemolysin b/d transporter is dependent on a signal sequence mapped to the c-t ...19938483936
the role of induced virulence factors produced by pasteurella haemolytica in the pathogenesis of bovine pneumonic pasteurellosis: review and hypotheses.in the pathogenesis of pneumonic pasteurellosis, there is an abrupt commensal to pathogen shift from a predominance of p. haemolytica serotype 2 (st2) to serotype 1 (st1) in the bovine upper respiratory tract (urt) microfloral population. this occurs following periods of stress associated with development of this disease. data are reviewed from recent publications supporting the contention that surface-expressed st1-specific factor(s) could be critical in mediating urt adhesion and colonization. ...19938485643
molecular analysis of the actinobacillus pleuropneumoniae rtx toxin-iii gene cluster.actinobacillus pleuropneumonia strains that secrete three different exotoxins (apxi, apxii, and apxiii) have been implicated in the etiology of porcine pleuropneumonia. to understand the role of these toxins in the pathogenesis of this disease, we have previously reported the cloning of the hemolysin gene (apxii) (chang et al., 1989a), which encodes a 110-kd polypeptide with hemolytic and cytotoxic activity. to clone the third toxin gene (apxiii), a new genomic library using a. pleuropneumoniae ...19938494611
evaluation of the rapid nh system for identification of haemophilus somnus, pasteurella multocida, pasteurella haemolytica, and actinobacillus pleuropneumoniae isolated from cattle and pigs with respiratory disease.haemophilus somnus, pasteurella haemolytica, pasteurella multocida, and actinobacillus pleuropneumoniae from cattle and pigs with respiratory disease were used to evaluate the rapid nh system (innovative diagnostics, atlanta, ga.). minor modifications of the rapid nh system to include animal source and growth requirements would permit the identification of all isolates tested.19938501242
disturbances in ex vivo vascular smooth muscle responses following exposure to pasteurella haemolytica vaccines.rats were vaccinated with saline (control) or one of the two commercially available pasteurella haemolytica vaccines presponse or precon-ph. animals were killed 3 days later and thoracic aorta removed for evaluation of the ex vivo biophysical responses to carbachol (cch). in some experiments, vascular endothelium was mechanically removed. vaccination of rats impairs the endothelial-dependent relaxation to cch. in vessels with endothelium removed, the contractile response to cch is converted into ...19938126761
[detection of atypical toxin-producing pasteurella strains on the nasal mucosa of calves and their differential diagnostic limits for pasteurella haemolytica and pasteurella multocida].the bacterial colonisation on nasal mucous membranes of calves at age of 3, 5 to 5 months was investigated by cotton swabs. three pasteurella species were found (p. multocida subspecies multocida, p. haemolytica, p. avium) as monocausal infection as well as pluricausal infection. p. avium was characterised by colonial morphology, bacterioscopy, biochemical properties, polypeptide-pattern in sds-page and by electronmicroscopic investigation and was differentiated from p. multocida and p. haemolyt ...19948129703
tissue factor expression in bovine endothelial cells induced by pasteurella haemolytica lipopolysaccharide and interleukin-1.pasteurella haemolytica in cattle produces fibrino-hemorrhagic pleuropneumonia characterized by extensive pulmonary microvascular thrombosis and parenchymal necrosis. the purpose of this in vitro study was to determine if p. haemolytica lipopolysaccharide (lps) promotes vascular thrombosis by inducing a procoagulant state in vascular endothelial cells. after treatment of confluent monolayers of bovine pulmonary artery endothelial cells with various concentrations of either p. haemolytica lps or ...19948140726
passive immunity to pasteurella haemolytica a1 in dairy calves: effects of preparturient vaccination of the dams.dairy cows from five herds were assigned to receive a commercial pasteurella haemolytica vaccine or no vaccine at all, administered at six and three weeks before parturition. vaccination was associated with increased leukotoxin neutralizing serum antibody titers in the dams (p < 0.001), and with increased titers in colostrum (p < 0.001). vaccination of dams also had a significant association with increased passive leukotoxin neutralizing antibody titers in their calves (p < 0.001). vaccination w ...19948143250
preparation of recombinant glycoprotease of pasteurella haemolytica a1 utilizing the escherichia coli alpha-hemolysin secretion system.three murine monoclonal antibodies were prepared against the recombinant glycoprotease of pasteurella haemolytica a1 expressed in escherichia coli. these monoclonal antibodies were able to recognize the authentic glycoprotease from p. haemolytica a1 culture supernatant. a recombinant plasmid which contained most of the glycoprotease gene of p. haemolytica a1 fused with the secretion signal sequence from hlya of the e. coli alpha-hemolysin determinant was constructed. this recombinant plasmid exp ...19948150268
bacteria isolated from nasal and tonsillar samples of clinically healthy rocky mountain bighorn and domestic sheep.nasal and tonsillar samples were collected from 14 free-ranging clinically healthy rocky mountain bighorn sheep (ovis canadensis canadensis) and 10 domestic sheep (ovis aries). we identified 194 bacterial isolates, including 101 from bighorn and 93 from domestic sheep. of these isolates, 115 were gram-positive and 79 were gram-negative. staphylococcus species were the most numerous gram-positive organisms and had a higher incidence in samples from domestic than from bighorn sheep. in contrast st ...19948151809
effects of modified cary and blair medium on recovery of nonhemolytic pasteurella haemolytica from rocky mountain bighorn sheep (ovis canadensis canadensis) pharyngeal swabs.modified cary and blair transport medium (mcb) was evaluated for recovery of pasteurella spp. from pharyngeal swabs of healthy rocky mountain bighorn sheep (ovis canadensis canadensis). in experiment one, three pharyngeal swabs were collected from each of 25 bighorns. pasteurella haemolytica was recovered from 21 of 25 swabs tested almost immediately and from 16 of 25 swabs held in mcb medium at about 22 c for 24 hr before testing (p > 0.10). recovery of p. haemolytica decreased (p < 0.005) to 1 ...19948151818
comparison of outer-membrane proteins of pasteurella haemolytica expressed in vitro and in vivo in cattle.outer-membrane protein (omp) profiles of two serotype a1 isolates of pasteurella haemolytica were compared by sds-page and western blotting with bovine convalescent serum after growth (a) in vitro under iron-sufficient and -deficient conditions, (b) in vivo in the lungs of experimentally infected calves and (c) in vivo in diffusion chambers implanted into the peritoneal cavities of calves. lung-grown bacteria differed from iron-sufficient in vitro-grown bacteria in having enhanced expression of ...19947881547
regulation of major histocompatibility complex class ii expression by pasteurella haemolytica leukotoxin.many properties have been associated with pasteurella haemolytica leukotoxin and other repeat-in-toxin toxins, including their cytotoxic activity on various cells of the lymphoid and nonlymphoid systems as well as their ability to modulate the immunological activity of lymphocytes and monocytes. in this study, we assessed the ability of p. haemolytica leukotoxin to affect the expression major histocompatibility complex (mhc) class ii molecules on bovine peripheral monocytes. peripheral blood mon ...19948168921
cleavage of epitectin, a mucin-type sialoglycoprotein, from the surface of human laryngeal carcinoma cells by a glycoprotease from pasteurella haemolytica.in this study we have assessed the action of a novel glycoprotease, secreted by the bovine pneumonia pathogen pasteurella haemolytica, on epitectin expressed on the surface of human laryngeal carcinoma (h.ep.2) cells. epitectin has been previously characterized as a high buoyant density glycoprotein of mass of over 350 kda extensively glycosylated on serine and threonine by small oligosaccharides. purified metabolically labeled epitectin was very effectively hydrolyzed by the glycoprotease. howe ...19948179312
static dna bending and protein interactions within the pasteurella haemolytica leukotoxin promoter region: development of an activation model for leukotoxin transcriptional control.in this study, we define cis-acting elements involved in regulation of the pasteurella haemolytica leukotoxin promoter. in place of a canonical promoter -35 sequence, the leukotoxin promoter contains four adenine-rich repeats of sequence ca6(c/t)a, phased at approximately 10-base intervals. dna fragments containing these repeats exhibit retarded mobility in polyacrylamide gels and permitted identification of a static dna bend in the promoter -70 region. deletion of the static dna bend caused a t ...19948179822
effect of pasteurella haemolytica infection on alpha 1-acid glycoprotein and albumin concentrations in serum and subcutaneous tissue chamber fluid of calves.thermoplastic tissue chambers were implanted subcutaneously in the paralumbar fossae of 10 calves. concentrations of alpha 1-acid glycoprotein (aag) and albumin in serum and subcutaneous tissue chamber fluid were measured before and after inoculation of pasteurella haemolytica into tissue chambers. two months after implantation, serum and tissue chamber fluid samples were collected and all tissue chambers were then inoculated with p haemolytica. additional serum and chamber fluid samples were co ...19948191004
antigenic composition of pasteurella haemolytica serotype-1 supernatants from supplemented and nonsupplemented media.supernatant preparations containing antigens produced by pasteurella haemolytica serotype 1 grown in nonsupplemented rpmi 1640 medium and 3 grown in supplemented rpmi 1640 media were evaluated. antigens were detected by immunoblotting each supernatant preparation with sera from 20 cattle with various degrees of resistance to experimentally induced pneumonic pasteurellosis. antigen-antibody bands at 49 and 30 kd were correlated with resistance in all 4 media. a 66-kd antigen-antibody band was cor ...19948192256
a 4-year survey of antimicrobial susceptibility trends for isolates from cattle with bovine respiratory disease in north america.the antimicrobial susceptibility trends of bovine respiratory disease (brd) pathogens isolated from 1988 to 1992 were determined. a total of 880 isolates representing pasteurella haemolytica, pasteurella multocida, and haemophilus somnus were used in the study. overall, resistance to ampicillin, tetracycline, erythromycin, and sulfamethazine was frequently encountered among strains of p. haemolytica and p. multocida. ceftiofur, an extended-spectrum cephalosporin originally marketed in 1988 for t ...19948195385
the bovine placentome in bacterial and mycotic abortions.placentomes were extracted from the uteri of 22 aborted cows and examined to detect the cause of abortion; fetuses or fetal abomasal contents from 15 of the cows were also examined. firm diagnoses of pasteurella haemolytica, actinomyces pyogenes, listeria monocytogenes, bacillus licheniformis, aspergillus fumigatus or mortierella wolfii abortion were made in 11 cases. the histopathological lesions showed some correlation with the identity of the bacterium isolated; the lesions of mycotic abortio ...19948197693
iron supply of pasteurella multocida and pasteurella haemolytica.pasteurella multocida and pasteurella haemolytica do not produce hydroxamate- or phenolate type siderophores. however, transport- and utilization systems could be detected for the well known siderophores ferrioxamine b, e, g, rhizoferrin and the intermediate 2,3-dihydroxybenzoic acid by means of cross-feeding tests in both pasteurella species. enterobactin and ferrichrome did not feed any of the pasteurella strains tested. additionally, alpha-ketoacids and alpha-hydroxyacids such as pyruvic acid ...19948207666
characterization of escherichia coli isolated from the tonsils of cattle.during our studies on tonsillar colonization by pasteurella haemolytica, we consistently found escherichia coli to be one of the most prominent and prevalent bacterial species in the tonsils of healthy cattle. since tonsillar isolates have not been characterized, we grouped 124 isolates from 87 healthy cattle from eight sources by hemolytic zone size and by carbon source utilization and probed them for selected virulence genes. they formed 3 groups by hemolytic zone size and 18 groups (of 2 to 3 ...19948126195
aortic graft infection due to pasteurella haemolytica and group c beta-hemolytic streptococcus.although infection is a rare complication of aortic bypass grafting, we treated a 50-year-old patient who developed aortic graft infection due to pasteurella haemolytica and group c beta-hemolytic streptococcus. the source of the infection could not be verified; however, after removal of the infected graft and administration of a 6-week course of intravenous ampicillin, he recovered fully. we discuss the etiology and pathogenesis of this rare infection.19947893884
studies of the pathology and microbiology of pneumonic lungs of lambs.the characteristics of lung lesions of slaughtered lambs and the presence of microorganisms in the lesions were investigated. pneumonia was detected in 500 (3.6%) of 13,588 lambs. macroscopical lesions were of atypical pneumonia and were often seen in the pars cranialis of lobus cranialis dexter. histologically, proliferative pneumonia was detected in most cases and was often accompanied by exudative characteristics. pasteurella haemolytica was isolated from 258 (51.6%) and mycoplasma ovipneumon ...19947895625
the detection of the sialoglycoprotease gene and assay for sialoglycoprotease activity among isolates of pasteurella haemolytica a1 strains, serotypes a13, a14, t15 and a16.polymerase chain reaction (pcr) using specific primers to the sialoglycoprotease gene (gcp) of pasteurella haemolytica biotype a, serotype 1 amplified a 1-kb fragment from each of p. haemolytica serotypes a7, a13, a14 and a16, but not t15; which was confirmed by southern blot hybridization analysis. using a sialoglycoprotease (gcp) activity assay, gcp activity was found in serotypes a13, a14 and a16. inclusion of these three serotypes confirms that all recognized a biotypes are positive for both ...19947926671
construction of isogenic mutants of pasteurella haemolytica by allelic replacement.we describe methods for the mutagenesis of cloned pasteurella haemolytica (gram-) genes and for the construction of p. haemolytica mutants by allelic exchange. we used these methods to construct isogenic mutants of p. haemolytica which no longer synthesize three membrane lipoproteins (lpp). a single genetic locus, consisting of three tandemly arranged genes encoding 28-30-kda membrane lpp, was replaced with a mutated locus which carries the beta-lactamase-encoding apr gene from a 4.2-kb p. haemo ...19947926822
in vivo production of neuraminidase by pasteurella haemolytica a1 in goats after transthoracic challenge.nine goats were injected transthoracically with pasteurella haemolytica a1 to determine if an extracellular bacterial enzyme, neuraminidase, was produced in vivo during infection with this organism. the principal group of goats (n = 9) each received 1 ml of 7.25 x 10(5) live p. haemolytica a1 cells in polyacrylate beads transthoracically in the left lung on days 0 and 21. six goats were used as negative controls and received 0.3 g of polyacrylate beads subcutaneously in the right flank on days 0 ...19947927740
[evaluation of phagocytosis, bactericidal effect, and cytotoxicity of pasteurella haemolytica and pasteurella multocida in bovine alveolar macrophages].evaluation of phagocytosis and bactericidal effect of pasteurella haemolytica and p. multocida was conducted on bovine alveolar macrophages freshly obtained through bronchioalveolar washings from live animals. cytotoxic activity of these bacteria on the alveolar macrophages was evaluated through the simple visual assay in microplates, using bovine blood leukocytes as a comparative target cell. in order to evaluate phagocytosis the following variables were considered p. haemolytica and p. multoci ...19947938943
identification of a potentially important antigen of pasteurella haemolytica.to identify antigens which may be important for stimulating immunity to pneumonic pasteurellosis, a bovine antiserum to whole p. haemolytica was used to screen a recombinant lambda gt11/p. haemolytica expression library. one of the recombinant bacteriophage clones identified with the bovine antiserum, sw20c, expressed a fusion protein which was also recognized by rabbit antiserum to partially purified p. haemolytica culture supernatant and was found to be immunogenic in guinea pigs. the guinea p ...19947941293
pasteurella haemolytica leukotoxin-induced synthesis of eicosanoids by bovine neutrophils in vitro.exposure of isolated bovine neutrophils to partially purified pasteurella haemolytica leukotoxin caused increased synthesis of leukotriene b4 (ltb4) but not thromboxane b2 (txb2) from endogenous arachidonic acid. synthesis of ltb4 was closely correlated with leukotoxin-induced neutrophil lysis. at low toxin concentrations, ltb4 production lagged behind leukotoxin-induced neutrophil lysis over a 3-h period. the neutralizing monoclonal antileukotoxin antibody mm601 neutralized both leukotoxin-indu ...19947964171
immediate responses in serum tnf alpha and acute phase protein concentrations to infection with pasteurella haemolytica a1 in calves.the concentrations of tumour necrosis factor-alpha (tnf alpha), serum amyloid a (saa) and haptoglobin were determined in serum samples taken from four calves in the 10 hours after their intra-tracheal inoculation with pasteurella haemolytica serotype a1. the concentration of haptoglobin did not increase but the concentration of saa rose progressively from within two hours of inoculation. the concentration of tnf alpha reached a peak in all the animals two hours after inoculation but had returned ...19947973087
growth-condition dependent expression of pasteurella haemolytica a1 outer membrane proteins, capsule, and leukotoxin.pasteurella haemolytica, strain p1148 (biotype a, serotype 1) was grown under iron-rich and iron-restricted conditions both with and without serum, and the outer membrane protein (omp), capsule, and leukotoxin production studied. omps were evaluated by sds-page and examined by immunoblot to identify antigens recognized by sera from p. haemolytica a1 convalescent and vaccinated cattle. capsule production was evaluated using fluorescent antibody staining and rapid plate agglutination reaction. leu ...19947975148
altered endothelium-dependent alpha-adrenergic vascular reactivity following exposure to pasteurella haemolytica antigens.rats were injected with sterile saline (controls), 10(5) cfu of pasteurella haemolytica (biotype a) obtained from a commercial vaccine, or a commercial pasteurella leukotoxoid vaccine. three days after vaccination, the animals were killed and the thoracic aorta was removed. in some experiments the vascular endothelium was mechanically removed. each isolated aorta was placed in a tissue bath and the biophysical responses to methoxamine (alpha-1 agonist) were determined. in separate experiments th ...19947975198
serotype-specific inhibition of colonization of the tonsils and nasopharynx of calves after pasteurella haemolytica serotype a1 after vaccination with the organism.vaccination of cattle with a tissue culture-derived pasteurella haemolytica serotype 1 vaccine elicited a serotype-specific inhibition of nasal and tonsillar colonization by the homologous serotype under field conditions. calves (n = 101) originated from a single farm, where half the calves were vaccinated. the calves were delivered to an order-buyer barn 105 days later, and given a second dose of vaccine. at the order-buyer barn, calves were mixed with 27 calves, some of which had clinical sign ...19947978650
an outbreak of infectious laryngotracheitis in california broilers.infectious laryngotracheitis (ilt) was diagnosed as the cause of an outbreak of respiratory disease in broiler chickens in california. the classical form of ilt is characterized by dyspnea, gasping, coughing, and expectoration of bloody exudate. most of the broilers submitted to the diagnostic laboratory showed a non-classical presentation of ilt, in which mucoid tracheitis and conjunctivitis were the most consistent lesions. historically, most of the ilt cases diagnosed in our laboratory have c ...19948002892
induction of acute bronchopneumonia in mice by intrabronchial inoculation of pasteurella haemolytica serotype 1.dose dependent pulmonary lesions of acute bronchopneumonia were induced in male, outbred swiss webster mice by intrabronchial inoculation of pasteurella haemolytica. five exponential dilutions ranging from 5 x 10(4) to 5 x 10(8) colony forming units per ml (cfu/ml) of pasteurella haemolytica serotype 1 were inoculated into five groups of mice. mice were killed by cervical dislocation 24 hours postinoculation. pulmonary lesions occurred in mice of all five groups, however, 5 x 10(7) cfu/ml was th ...19948004544
sialoglycoprotease of pasteurella haemolytica a1: detection of antisialoglycoprotease antibodies in sera of calves.log phase culture supernate from pasteurella haemolytica biotype a, serotype 1 contains a proteolytic enzyme specific for o-sialoglycoproteins. using two methods, western immunoblotting and enzyme neutralization assay, it was demonstrated that certain bovine sera from two previous p. haemolytica a1 vaccination and challenge trials contained antibodies (ab) (isotypes igg1 and igg2 on western immunoblot) to the sialoglycoprotease (gcp). in these trials, selected calves were vaccinated twice with e ...19948004547
variation in outer-membrane protein and lipopolysaccharide profiles of pasteurella haemolytica isolates of serotypes a1 and a2 obtained from pneumonic and healthy cattle.the outer-membrane protein (omp) and lipopolysaccharide (lps) profiles of 29 isolates of pasteurella haemolytica serotypes a1 (18 isolates) and a2 (11 isolates), obtained from pneumonic (13 isolates) or healthy (16 isolates) cattle, were compared by sds-page and western blot analysis. coomassie-blue-stained omp profiles of serotype a1 and a2 isolates could be distinguished from each other by differences in both major and minor proteins. whereas the omp profiles of the serotype a1 isolates were e ...19948012599
administration of a bolus formulation of baquiloprim and sulphadimidine to calves: plasma concentration--time profiles and efficacy in suppressing experimental pneumonic pasteurellosis.after administration of a bolus containing 0.8 g baquiloprim and 7.2 g sulphadimidine to six calves, plasma concentrations of these compounds exceeded mics for pasteurella haemolytica from about 3 hours to at least 48 hours. experimental infection of three calves with 2.8 x 10(10) p. haemolytica type a1 organisms by the endobronchial route resulted in extensive pneumonic lesions, and smaller, similar lesions were found post mortem in two other calves which had received the same inoculum. nine si ...19948017029
evaluation of an orally administered vaccine, using hydrogels containing bacterial exotoxins of pasteurella haemolytica, in cattle.poly(methacrylic acid) hydrogels were tested for oral delivery of a vaccine against pasteurella haemolytica infection in cattle. culture supernatants of p haemolytica, the most common bacterium associated with pneumonia in cattle, were used as the antigens in the vaccine. hydrogels containing culture supernatants were administered orally to calves. calves were then challenge-exposed with virulent p haemolytica. calves were euthanatized 3 days after challenge exposure. the lungs of each calf were ...19948017696
fatal pneumonia following inoculation of healthy bighorn sheep with pasteurella haemolytica from healthy domestic sheep.in a series of three experiments, isolates of pasteurella haemolytica biotype a, serotype 2, ribotype reference wsu-1, from healthy domestic sheep, were inoculated intratracheally into eight bighorn sheep (ovis canadensis canadensis) and seven domestic sheep with doses of bacteria ranging from 5.3 x 10(8) to 8.6 x 10(11) colony forming units. seven of eight inoculated bighorn sheep died from acute pneumonia within 48 hr of inoculation, whereas all seven domestic sheep inoculated with comparable ...19948028096
a reliable transport method for isolating pasteurella haemolytica from bighorn sheep.we compared three transport methods for the recovery of pasteurella haemolytica from pharyngeal swabs collected under field conditions from 42 bighorn sheep (ovis canadensis) in one captive and three free-ranging populations. transport methods included: amies medium with charcoal, transported on ice, and cultured on blood agar within 24 hr; direct plating on blood agar, transported on heating pads, and incubated at 37 c within 8 hr of collection; and phosphate buffered glycerol (pbg), transporte ...19948028114
characterization of a restriction endonuclease, phai, from pasteurella haemolytica serotype a1 and protection of heterologous dna by a cloned phai methyltransferase gene.pasteurella haemolytica is the leading cause of economic loss to the beef cattle industry in the united states and an important etiologic agent worldwide. study of p. haemolytica is hindered by researchers' inability to genetically manipulate the organism. a new restriction endonuclease, phai, an isoschizomer of sfani (r. j. roberts, methods enzymol. 65:19-36, 1980), was isolated from p. haemolytica serotype 1, strain nadc-d60, obtained from pneumonic bovine lung. phai recognizes the 5-base nonp ...19948031094
molecular gene cloning and nucleotide sequencing and construction of an aroa mutant of pasteurella haemolytica serotype a1.the aroa gene of pasteurella haemolytica serotype a1 was cloned by complementation of the aroa mutation in escherichia coli k-12 strain ab2829. the nucleotide sequence of a 2.2-kb fragment encoding aroa predicted an open reading frame product 434 amino acids long that shows homology to other bacterial aroa proteins. several strategies to inactivate aroa were unsuccessful. gene replacement was finally achieved by constructing a replacement plasmid with aroa inactivated by insertion of a p. haemol ...19948031095
construction of conjugative shuttle and suicide vectors for pasteurella haemolytica and p. multocida.a shuttle cloning vector, paka16, and suicide derivatives paka19 and paka22 have been developed for gene transfer to pasteurella haemolytica and p. multocida. paka16 was constructed by insertion of the lacz alpha-peptide-encoding region and a multiple cloning site into a plasmid which was originally isolated from p. haemolytica serotype a1. the vector encodes ampicillin resistance, and contains at least 14 unique restriction sites and the property of phenotypic identification of recombinant clon ...19948045428
distribution of anti-cd68 (ebm11) immunoreactivity in formalin-fixed, paraffin-embedded bovine tissues.a commercially acquired anti-human macrophage antibody (anti-cd68; ebm11) was used in an immunocytochemical technique to detect macrophages in formalin-fixed, paraffin-embedded tissues from cattle, pigs, humans, rats, turkeys, dogs, and cats. in healthy cattle, the antibody labeled alveolar macrophages, pulmonary intravascular cells (presumably intravascular macrophages), and macrophage-like cells in other tissues. in bovine lungs infected with pasteurella haemolytica, ebm11 antibody labeled 95% ...19948053129
monofrequency forced oscillation technique for the investigation of pulmonary function in calves: in vitro and in vivo studies.parameters derived from the non-invasive and simple monofrequency forced oscillation technique were compared with classical parameters of ventilatory mechanics in order to assess its usefulness for the investigation of pulmonary function in calves. to facilitate this comparison, theoretical derivations were coupled with in vitro measurements, using an artificial lung model, and with in vivo studies. these studies compared the oscillatory resistance parameters (ros and re) and the respiratory sys ...19948073189
transferrin receptors on ruminant pathogens vary in their interaction with the c-lobe and n-lobe of ruminant transferrins.the interaction between ruminant transferrins and receptor proteins on the surface of the ruminant pathogens pasteurella haemolytica, haemophilus somnus, pasteurella multocida, haemophilus agnii, and moraxella bovis was evaluated by a combination of binding assays and affinity isolation procedures. membranes isolated from p. haemolytica, p. multocida, and h. agnii were capable of binding sheep, goat, and cattle transferrins whereas binding by membranes from h. somnus and m. bovis was specific fo ...19948076248
the effect of a combined pasteurella haemolytica and haemophilus somnus vaccine and a modified-live bovine respiratory syncytial virus vaccine against enzootic pneumonia in young beef calves. 19948076280
a leukotoxin nonproducing mutant of pasteurella haemolytica. phagocytosis and killing by bovine polymorphonucleocytes. 19948080187
antimicrobial susceptibility of pasteurella haemolytica and pasteurella multocida isolated from pneumonic ovine lungs.the in vitro susceptibilities of pasteurella haemolytica biotypes a and t and p multocida from pneumonic ovine lungs to penicillin, ampicillin, oxytetracycline, chloramphenicol, erythromycin, kanamycin, neomycin, gentamicin, streptomycin and lincomycin were determined by the disk diffusion method. all the isolates were sensitive to chloramphenicol and resistant to lincomycin. the isolates of p haemolytica biotype a were consistently more sensitive to penicillin, ampicillin, oxytetracycline, eryt ...19948085324
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
pasteurella haemolytica a2 infection in two sheep flocks in tripoli area (libya).330 sheep from two different flocks were examined for respiratory manifestations including serous to mucopurulent nasal discharge dyspnoea, cough and light depression. 55 animals were sick (16.6%) and 13 died (3.9%). samples were taken from healthy, diseases and dead cases as well. pasteurella haemolytica a2 was identified from 18 isolates, and serotyped by rapid plate agglutination (rpa). drug susceptibility was tested and treatment applied in line with the results.19947709029
[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
comparative leukotoxicities of pasteurella haemolytica isolates from domestic sheep and free-ranging bighorn sheep (ovis canadensis).twenty-eight isolates of pasteurella haemolytica from domestic sheep (n = 14 isolates) and bighorn sheep (n = 14 isolates) were evaluated for leucotoxicity against peripheral blood neutrophils of bighorn sheep by adding bacterial culture supernatants to bighorn sheep neutrophils in vitro. leukotoxic isolates of p. haemolytica, defined as causing > 50% neutrophil death as measured by release of lactate dehydrogenase into culture supernatants, were identified from eight of 14 domestic sheep isolat ...19947760481
susceptibility of phagocytes from elk, deer, bighorn sheep, and domestic sheep to pasteurella haemolytica cytotoxins.alveolar macrophages and peripheral blood neutrophils from elk (cervus elaphus), bighorn sheep (ovis canadensis canadensis), and domestic sheep were exposed to culture supernatants from pasteurella haemolytica isolated from bighorn sheep and domestic sheep. in a second experiment, peripheral blood neutrophils from mule deer (odocoileus hemionus), elk, and bighorn sheep were exposed to culture supernatants from p. haemolytica isolated from elk, bighorn sheep and domestic sheep. alveolar macrophag ...19947760482
bovine neutrophil activation by culture fluid from pasteurella haemolytica serotypes a1 and a11.neutrophil activation has been thought to contribute to the pathogenesis of fibrinous pneumonia caused by pasteurella haemolytica serotype a1. the activation of bovine neutrophils by culture fluid from the pathogenic p. haemolytica serotype a1 and the non-pathogenic serotype a11 was compared. logarithmic-phase bacteria of each serotype were incubated in rpmi 1640-medium for 3 h at 37 degrees c. the culture fluid was collected by centrifugation and concentrated by ultrafiltration. the concentrate ...19947801531
enhancement of pasteurella haemolytica leukotoxic activity by bovine serum albumin.growth of pasteurella haemolytica a1 in rpmi 1640 medium containing 0.5% bovine serum albumin (bsa) for 2.5 hours enhanced culture supernatant leukotoxic activity (30,700 +/- 12,900 toxic units/ml, compared with leukotoxic activity of culture supernatants produced in rpmi 1640 medium alone (120 +/- 40 toxic units/ml). gel filtration chromatography of the leukotoxic activity from rpmi 1640 medium supernatants in buffer containing 50 mm nacl indicated a single leukotoxic activity peak (peak i) elu ...19947802395
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
development of an intraperitoneal implant chamber for the study of in vivo-grown pasteurella haemolytica in cattle.an intraperitoneal implant chamber was developed for the study of the in vivo growth of pasteurella haemolytica in calves. the chamber had a volume of approximately 100 ml and featured an external sampling port which allowed multiple and sequential sampling of the chamber contents. a single polycarbonate diffusion membrane with a pore size of 0.22 micron allowed host peritoneal fluid to diffuse into the chamber and maintained the bacterial population free of white blood cells. chambers were impl ...19947830529
construction and vaccine potential of an aroa mutant of pasteurella haemolytica.the aroa gene, encoding 5-enolpyruvylshikimate 3-phosphate synthase, from pasteurella haemolytica biotype a, serotype 1 was cloned by complementation of the aroa mutation in escherichia coli strain ab2829 after electroporation with a dna library constructed in puc18. the cloned p. haemolytica aroa gene was inactivated by insertion of a kanamycin resistance gene and reintroduced by allelic exchange into the chromosome of the parental p. haemolytica using pbluescriptii sk+. the p. haemolytica aroa ...19947839583
effects of localized pasteurella haemolytica infection on erythromycin-binding properties of bovine alpha-1-acid glycoprotein, albumin, serum, and tissue chamber fluids.the in vitro erythromycin-binding properties of bovine alpha-1-acid glycoprotein (aag) and albumin were studied by using equilibrium dialysis. in addition, the proportions of free erythromycin in bovine serum and tissue chamber fluid before and 4 days after inoculation of subcutaneous tissue chambers with pasteurella haemolytica were measured. at a concentration of 5 micrograms/ml, erythromycin was moderately bound to aag (39% +/- 4% free) and was only slightly bound to albumin (86% +/- 2% free) ...19947840576
proteasome sequences in eubacteria. 19947846763
analysis of toxinogenic functions associated with the rtx repeat region and monoclonal antibody d12 epitope of escherichia coli hemolysin.amino acids (aa) 550 through 850 of the escherichia coli hemolysin (hlya) contain sequences important for several steps in cytolysis. these include the ca(2+)-binding glycine-rich tandem repeats recognized by the monoclonal antibody a10, the putative hlyc-dependent acylation site that corresponds to the monoclonal antibody d12 epitope, and the erythrocyte specificity domain which confers erythrolytic activity to the pasteurella haemolytica leukotoxin. to further investigate the toxinogenic funct ...19947507896
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
differential colon cancer cell adhesion to e-, p-, and l-selectin: role of mucin-type glycoproteins.e-, p-, and l-selectin support the adhesion of leukocytes to the vessel wall through the recognition of specific carbohydrate ligands, which often contain sialylated, fucosylated lactosamines such as sialyl lewis x [slex; neu5ac alpha 2-3gal beta 1-4(fuc alpha 1-3)glcnac-]. e-selectin expressed by activated endothelium has been shown to support the adhesion of slex-bearing colon cancer cells. in the present study, we examine the interactions of multiple colon cancer cell lines with all three sel ...19957545541
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
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
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
development of a peroxidase-antiperoxidase (pap) technique for the identification of haemophilus somnus in pneumonic calf lungs in denmark.a peroxidase-antiperoxidase (pap) technique was developed for the identification of haemophilus somnus bacteria in lung tissues of calves. antisera raised against somatic and wall antigens of a danish and american strain of h. somnus were produced. experimentally infected murine tissues were used for the determination of the sensitivity and specificity of antiserum that had been heterologously absorbed with antigens of cross-reacting bacteria, i.e. pasteurella haemolytica and pasteurella multoci ...19957576570
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
Refresh
firstprev
12345678910...
nextlast
Displaying items 701 - 800 of 1767