Identification of a potentially important antigen of pasteurella haemolytica     

S.K. Weldon  D.A. Mosier  K.R. Simons  R.C. Craven  A.W. Confer 《Veterinary microbiology》1994,40(3-4):283-291

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 pig antibody recognized a 100 kDa protein in P. haemolytica cell lysates. Sequence analysis of the cloned DNA from SW20C identified a fragment of 1443 bp with a small open reading frame that was contiguous with the lacZ sequence. The 153 bp P. haemolytica-specific open reading frame encoded a polypeptide of approximately 6kDa. Homology searches of Genbank and the EMBL data bases revealed no homology of this open reading frame with any other bacterial sequences including P. haemolytica leukotoxin and Ssa1. Evaluation of sera from calves that were scored either susceptible or resistant to experimental pneumonic pasteurellosis demonstrated a significant (P < 0.001) correlation between the intensity of the antibody response to the SW20C antigen and resistance to disease.  相似文献   

Haemoglobin and packed cell volume of yaks at high altitude     

H. WINTER  U. TSHEWANG  BJ GURUNG  AW BEATTIE 《Australian veterinary journal》1989,66(9):299-301

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Spinal dysraphism: a congenital myelodysplasia in the Weimaraner   总被引：1，自引：0，他引：1  

A W Confer  B C Ward 《Journal of the American Veterinary Medical Association》1972,160(10):1423-1426

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Effect of prior natural exposure to Pasteurella haemolytica on resistance to experimental bovine pneumonic pasteurellosis   总被引：6，自引：0，他引：6  

A W Confer  R J Panciera  R W Fulton 《American journal of veterinary research》1984,45(12):2622-2624

The effect of prior natural exposure to Pasteurella haemolytica, as determined serologically, was studied with respect to resistance to experimental pneumonic pasteurellosis in 20 calves from 3 experiments. Resistance to challenge exposure was measured using a lesion-scoring system. As measured by a quantitative fluorometric immunoassay, naturally acquired serum antibody titers to the organisms were 0 to 228. There was a significant correlation (P less than 0.05) between high naturally acquired antibody titers and resistance to transthoracic challenge exposure with P haemolytica.  相似文献   

Characterization of,and immune responses of mice to,the purified OmpA-equivalent outer membrane protein of Pasteurella multocida serotype A:3 (Omp28)     

Gatto NT  Dabo SM  Hancock RE  Confer AW 《Veterinary microbiology》2002,87(3):221-235

Pasteurella multocida A:3 is a major cause of bovine pneumonia. A major antigenic heat-modifiable 28kDa outer membrane protein (Omp28) was previously identified. The purpose of this study was to purify and characterize Omp28 immunologically and structurally. Omp28 was extracted from N-lauroylsarcosine-insoluble protein preparations by a combination of detergent fractionation with Zwittergent 3-14 and chromatography. Partial N-terminal amino acid sequence confirmed Omp28 as a member of the OmpA-porin family. However, porin activity could not be demonstrated in a lipid-bilayer assay. Heat modifiability of purified Omp28 was demonstrated, and Omp28 was found in outer membrane fraction of P. multocida. Surface exposure of Omp28 was demonstrated by partial protease digestion of intact bacteria, by binding of anti-Omp28 polyclonal ascites fluid to the bacterial surface, and by partial inhibition of anti-outer membrane antiserum binding by previous incubation of the bacteria with anti-Omp28 serum. CD-1 mice vaccinated with purified Omp28 developed a significant antibody titer (P<0.05) compared to the control treatment group but were not protected from a homologous intraperitoneal bacterial challenge. By contrast, treatment groups vaccinated with P. multocida outer membrane, formalin-killed P. multocida or a commercial vaccine were significantly protected from challenge. In vitro complement-mediated killing of P. multocida was observed in post-vaccination sera of outer membrane, formalin-killed P. multocida, and commercial vaccine-treatment groups, but not with sera from the Omp28-treatment group. In conclusion, although Omp28 is surface exposed and antigenic, it may not be a desirable immunogen for stimulating immunity to P. multocida.  相似文献   

Single primer polymerase chain reaction fingerprinting for Pasteurella multocida isolates from laboratory rabbits     

Dabo SM  Confer AW  Lu YS 《American journal of veterinary research》2000,61(3):305-309

OBJECTIVE: To evaluate a rapid polymerase chain reaction (PCR) fingerprinting technique for discriminating among Pasteurella multocida isolates from laboratory rabbits. SAMPLE POPULATION: 33 P multocida isolates from rabbits with clinical pasteurellosis. PROCEDURE: PCR assays were conducted with 2 minisatellites (core sequence and modified core sequence of phage M13) and 2 microsatellites ([GTG]5 and [GACA]4). Each bacterium was assigned to a PCR type for each of the primers used. Boiled bacterial extracts and purified genomic DNA were compared by use of PCR assays for phage M13 and (GACA)4. Plasmids were isolated from each bacterium, and their influence on PCR fingerprint was determined, using boiled extracts as a DNA source. RESULTS: M13 core sequence and M13 modified core sequence yielded 5 and 8 PCR types, respectively. The microsatellites (GTG)5 and (GACA)4 yielded 4 and 9 PCR fingerprint types, respectively. Fingerprint patterns obtained by use of isolated DNA differed from those obtained by use of boiled extracts, although discrimination among P multocida isolates was similar. The presence or absence of plasmids did not affect PCR fingerprints. CONCLUSION: Single primer PCR fingerprinting with minisatellite and microsatellite primers is an efficient and reproducible method for the discrimination of P multocida isolates from rabbits and can be performed directly, using boiled bacterial extracts as a source of template, although more bands were obtained from pure genomic DNA.  相似文献   

Top 20 environmental weeds for classical biological control in Europe: a review of opportunities, regulations and other barriers to adoption   总被引：4，自引：3，他引：4  

AW SHEPPARD  RH SHAW†  & R SFORZA‡ 《Weed Research》2006,46(2):93-117

Classical biological control remains the only tool available for permanent ecological and economic management of invasive alien species that flourish through absence of their co‐evolved natural enemies. As such, this approach is recognized as a key tool for alien species management by the Convention on Biological Diversity (CBD), the European and Mediterranean Plant Protection Organization (EPPO) and the European Strategy on Invasive Alien Species (ESIAS). Successful classical biological control programmes abound around the world, despite disproportionate attention being given to occasional and predictable non‐target impacts. Despite more than 130 case histories in Europe against insect pests, no exotic classical biological control agent has been released in the EU against an alien invasive weed. This dearth has occurred in the face of increasing numbers of exotic invasive plants being imported and taking over National Parks, forests and amenity areas in this region, as well as a global increase in the use of classical biological control around the world. This paper reviews potential European weed targets for classical biological control from ecological and socioeconomic perspectives using the criteria of historical biological control success, taxonomic isolation from European native flora, likely availability of biological control agents, invasiveness outside Europe and value to primary industry and horticulture (potential for conflicts of interest). We also review why classical biological control of European exotic plants remains untested, considering problems of funding and public perception. Finally, we consider the regulatory framework that surrounds such biological control activities within constituent countries of the EU to suggest how this approach may be adopted in the future for managing invasive exotic weeds in Europe.  相似文献   

Trachymene glaucifolia associated with bentleg in lambs     

AW PHILBEY 《Australian veterinary journal》1990,67(12):468-468

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Transient enhancement of the serum antibody response to Brucella abortus strain 19 in cattle treated with levamisole     

A W Confer  S M Hall  B H Espe 《American journal of veterinary research》1985,46(12):2440-2443

Two experiments were done on 57 steers. These cattle were allotted to 8 groups (4 groups/experiment) and vaccinated with 1 to 3 X 10(9) colony-forming units of Brucella abortus strain 19. Cattle in 3 of the 4 groups/experiment were given 6 mg of levamisole/kg, subcutaneously, either at the time of vaccination (day 0), 7 days later, or at both times. Serum antibody titers to B abortus were measured sequentially for 28 days in experiment 1 and for 56 days in experiment 2, using the card test, Rivanol test, complement-fixation test, fluorometric immunoassay, and an enzyme-linked immunosorbent assay. In general, the highest mean antibody titers, as determined by all serologic tests, occurred in steers treated with levamisole at 7 days after vaccination or in those treated at the time of vaccination and 7 days later. By the card test on day 56, there was a significantly (P less than 0.05) greater number of seropositive cattle among those given levamisole 7 days after seropositive cattle among those given strain 19 alone. Simultaneous administration of strain 19 and levamisole did not alter antibody responses to B abortus.  相似文献   

Immunomodulation in cattle immunized with Brucella abortus strain 19     

J H Wyckoff  A W Confer 《Veterinary immunology and immunopathology》1990,26(4):367-383

Regulation of the bovine immune response to immunization with Brucella abortus Strain 19 (S19) was investigated through application of a modification of an assay to measure suppressor T lymphocyte activities in humans and through development and characterization of antigen-stimulated T lymphocyte lines in vitro. A total of nine of steers were alloted into two groups: control (n = 4) and S19-immunized (n = 5). Peripheral blood mononuclear cells (PBMC) from each animal were cultured in vitro with mitogens (concanavalin A (Con A) and pokeweed mitogen (PWM], B. abortus antigens (B. abortus soluble antigen (BASA) and whole heat-killed B. abortus cells (HKC)) and media alone periodically from days 4 through 49 of the experiment. Supernates from these cultures were assayed for immunomodulatory activity(s) by addition to indicator cultures stimulated with suboptimal concentrations of Con A. Supernates from PBMC of S19-immunized steers generated with B. abortus antigens significantly (P less than 0.05) suppressed indicator cell responses as compared to those from control steers on days 35 and 49 post-immunization. This suppressive activity from PBMC of immunized cattle with respect to that of control cattle could also be induced through mitogenic stimulation with Con A or PWM. On day 49 of the study, suppressive activity was spontaneously released from the PBMC of immunized cattle. T lymphocyte lines were initiated from two S19-immunized steers at 2 and 9 weeks post-immunization. These T cell lines were characterized with respect to proliferative responses to B. abortus antigens through in vitro assay and surface marker expression through indirect immunofluorescence with a limited panel of monoclonal antibodies. Results from the present study indicated that S19 immunization induces a subpopulation(s) of cells in the PBMC of cattle capable of regulating the in vitro response to B. abortus. This regulatory activity is detectable by in vitro assay as early as 7 weeks post-immunization. Furthermore, the regulatory cell(s) appear to involve BoCD8+ T, lymphocytes which are specific for B. abortus antigens.  相似文献