Immune responses of mice to vaccinia virus recombinants expressing either Listeria monocytogenes partial listeriolysin or Brucella abortus ribosomal L7/L12 protein     

Baloglu S  Boyle SM  Vemulapalli R  Sriranganathan N  Schurig GG  Toth TE 《Veterinary microbiology》2005,109(1-2):11-17

The Brucella abortus L7/L12 gene encoding ribosomal protein L7/L12 and the Listeria monocytogenes partial hly gene encoding the protective region of the hemolysin (partial listeriolysin, pLLO) were cloned into vaccinia virus by homologous recombination to produce recombinants WRL7/L12 and WRpLLO, respectively. The ability of these recombinants to induce humoral, cell mediated and protective immune response in mice was assessed. Although mice inoculated with WRL7/L12 recombinant produced antibodies specific to vaccinia virus and L7/L12 antigens, they were not protected against a virulent challenge with B. abortus 2308 strain. In contrast, mice inoculated with WRpLLO were protected against a challenge with virulent L. monocytogenes. Stimulation with purified fusion listeriolysin protein (MBP-LLO), but not with unrelated control protein (MBP), induced splenocytes from WRpLLO-inoculated mice to secrete significantly higher amounts of IFN-gamma than saline inoculated mice. Mice inoculated with either WRpLLO or WRL7/L12 recombinants produced predominantly IgG2a isotype antibody responses, indicative of a Th1 type of immune response. The protective potential of the WRpLLO recombinant correlated with the level of IFN-gamma produced in these mice.  相似文献   

Acute post-parturient haemoglobinuria in dairy cows and phosphorus status     

Stockdale CR  Moyes TE  Dyson R 《Australian veterinary journal》2005,83(6):362-366

During the conduct of an experiment designed to examine the nutritional management of dairy cows in late pregnancy, four cows out of 72 suffered from acute haemoglobinuria two to four weeks after calving. Thirty-six thin and 36 fat cows were individually fed one of three diets based on a total mixed ration with different energy or protein concentrations during the last 3 to 4 weeks before expected calving date. After calving, cows grazed pasture and were offered 6 kg dry matter of pelleted concentrates daily. The P concentrations of the feeds offered suggested that the cows' diets were marginally deficient in P relative to requirements. Plasma P concentrations were significantly (P < 0.05) lower in fat cows than in thin cows during the first 6 weeks of lactation (0.87 versus 1.12 mmol/L), but precalving diet had no effect (P > 0.05). Concentrations of plasma inorganic P of the four fat cows that developed acute haemoglobinuria were less than 0.3 mmol/L. However, plasma P concentrations in another 12 cows, none of which displayed overt symptoms, declined to similar levels. It appeared that inadequate dietary P may have predisposed cows to acute haemoglobinuria, but the precipitating cause was not readily obvious.  相似文献   

Evaluation of cardiac lesions and risk factors associated with myocarditis and dilated cardiomyopathy in southern sea otters (Enhydra lutris nereis)     

Kreuder C  Miller MA  Lowenstine LJ  Conrad PA  Carpenter TE  Jessup DA  Mazet JA 《American journal of veterinary research》2005,66(2):289-299

OBJECTIVE: To describe cardiac lesions and identify risk factors associated with myocarditis and dilated cardiomyopathy (DCM) in beach-cast southern sea otters. ANIMALS: Free-ranging southern sea otters. PROCEDURE: Sea otters were necropsied at the Marine Wildlife Veterinary Care and Research Center from 1998 through 2001. Microscopic and gross necropsy findings were used to classify sea otters as myocarditis or DCM case otters or control otters. Univariate, multivariate, and spatial analytical techniques were used to evaluate associations among myocarditis; DCM; common sea otter pathogens; and potential infectious, toxic, and nutritional causes. RESULTS: Clusters of sea otters with myocarditis and DCM were identified in the southern aspect of the sea otter range from May to November 2000. Risk factors for myocarditis included age, good body condition, and exposure to domoic acid and Sarcocystis neurona. Myocarditis associated with domoic acid occurred predominantly in the southern part of the range, whereas myocarditis associated with S. neurona occurred in the northern part of the range. Age and suspected previous exposure to domoic acid were identified as major risk factors for DCM. A sample of otters with DCM had significantly lower concentrations of myocardial L-carnitine than control and myocarditis case otters. CONCLUSIONS AND CLINICAL RELEVANCE: Cardiac disease is an important cause of death in southern sea otters. Domoic acid toxicosis and infection with S. neurona are likely to be 2 important causes of myocarditis in sea otters. Domoic acid-induced myocarditis appears to progress to DCM, and depletion of myocardial L-carnitine may play a key role in this pathogenesis.  相似文献   

Genotyping of Mycoplasma gallisepticum and M. synoviae by Amplified Fragment Length Polymorphism (AFLP) analysis and digitalized Random Amplified Polymorphic DNA (RAPD) analysis     

Feberwee A  Dijkstra JR  von Banniseht-Wysmuller TE  Gielkens AL  Wagenaar JA 《Veterinary microbiology》2005,111(1-2):125-131

Mycoplasma gallisepticum (MG) and M. synoviae (MS) are the cause of considerable economic losses in the poultry industry. Molecular differentiation of avian Mycoplasma strains may be helpful in tracing infections and in the evaluation of implemented intervention strategies. Amplified Fragment Length Polymorphism (AFLP) has shown to be a powerful typing technique but the application for poultry Mycoplasma strains is very limited. The aim of this study was to evaluate the reproducibility and discriminatory power of AFLP HindIII/HhaI and AFLP BglII/Mfel for the inter- and intraspecies differentiation of avian mycoplasmas and to compare these test characteristics with digitalized Random Amplified Polymorphic DNA (RAPD) analysis. The reproducibility of RAPD, AFLP HindIII/HhaI and AFLP BglII/Mfel was 50-100, 97-98 and 86-99%, respectively. RAPD and both AFLP enzyme combinations were able to differentiate between five avian Mycoplasma species. For AFLP, five MG and four MS clusters could be identified. The phylogenetic tree for both enzyme combinations was comparable. For RAPD, four MG clusters could be identified. For MS, however, due to the poor reproducibility of the RAPD technique, no clear genogroups could be identified. On basis of the results of this study it can be concluded that AFLP is a powerful technique for the genotyping of avian mycoplasmas and that, although AFLP HindIII/HhaI generated patterns with less fragments, the final results showed homologous results.  相似文献   

Evidence for occurrence of an organophosphate-resistant type of acetylcholinesterase in strains of sea lice (Lepeophtheirus salmonis Krøyer)     

Fallang A  Ramsay JM  Sevatdal S  Burka JF  Jewess P  Hammell KL  Horsberg TE 《Pest management science》2004,60(12):1163-1170

Acetylcholinesterase (AChE) is the target of a major pesticide family, the organophosphates, which were extensively used as control agents of sea lice on farmed salmonids in the early 1990s. From the mid‐1990s the organophosphates dichlorvos and azamethiphos were seriously compromised by the development of resistance. AChE insensitive to organophosphate chemotherapeutants has been identified as a major resistance mechanism in numerous arthropod species, and in this study, target‐site resistance was confirmed in the crustacean Lepeophtheirus salmonis Krøyer isolated from several fish‐farming areas in Norway and Canada. A bimolecular rate assay demonstrated the presence of two AChE enzymes with different sensitivities towards azamethiphos, one that was rapidly inactivated and one that was very slowly inactivated. To our knowledge this is the first report of target‐site resistance towards organophosphates in a third class of arthropods, the Crustacea. Copyright © 2004 Society of Chemical Industry  相似文献   

Identification of a maize kernel stress-related protein and its effect on aflatoxin accumulation     

Chen ZY  Brown RL  Damann KE  Cleveland TE 《Phytopathology》2004,94(9):938-945

ABSTRACT Aflatoxins are carcinogens produced mainly by Aspergillus flavus during infection of susceptible crops such as maize. Through proteomic comparisons of maize kernel embryo proteins of resistant and susceptible genotypes, several protein spots previously were found to be unique or upregulated in resistant embryos. In the present study, one of these protein spots was sequenced and identified as glyoxalase I (GLX-I; EC 4.4.1.5). The full-length cDNA of the glyoxalase I gene (glx-I) was cloned. GLX-I constitutive activity was found to be significantly higher in the resistant maize lines compared with susceptible ones. After kernel infection by A. flavus, GLX-I activity remained lower in susceptible genotypes than in resistant genotypes. However, fungal infection significantly increased methylglyoxal (MG) levels in two of three susceptible genotypes. Further, MG was found to induce aflatoxin production in A. flavus culture at a concentration as low as 5.0 muM. The mode of action of MG may be to stimulate the expression of aflR, an aflatoxin biosynthesis regulatory gene, which was found to be significantly upregulated in the presence of 5 to 20 muM MG. These data suggest that GLX-I may play an important role in controlling MG levels inside kernels, thereby contributing to the lower levels of aflatoxins found in resistant maize genotypes.  相似文献   

Colostral transmission of maedi visna virus: sites of viral entry in lambs born from experimentally infected ewes     

Preziuso S  Renzoni G  Allen TE  Taccini E  Rossi G  DeMartini JC  Braca G 《Veterinary microbiology》2004,104(3-4):157-164

Maedi visna virus (MVV) vertical transmission in sheep via infected colostrums is a very important route of infection in lambs. To verify colostral transmission and to study early viral entry in lambs, colostrum samples, and small intestine and mesenteric lymph nodes of lambs born from experimentally infected ewes were examined by histopathology, immunohistochemistry (IHC) and in situ hybridisation (ISH) studies. In particular, newborn lambs were naturally fed maternal colostrum and humanely killed at 10, 24, 48, 72, 96 h and 7 and 10 days after birth; two caesarian-derived lambs served as uninfected controls. No lesions suggestive of MVV infection were found, but marked immunoreactions for MVV capsid antigen (CA, p28) were detected in lambs fed maternal colostrum and in macrophages cultured from colostrum. IHC results in lambs suggest an initial viral absorption by intestinal epithelial cells at the tip of the villi, passage to mononuclear cells in the lamina propria and involvement of ileum Peyers' patches and mesenteric lymph nodes, with different staining patterns depending on infection times. ISH on intestinal sections of the 72 h lamb revealed the presence of proviral DNA in epithelial cells at the tip of the villi, suggesting a role for these cells in early MVV replication. The results contribute to knowledge about the pathogenesis of ovine lentivirus infection suggesting that the small intestine and mesenteric nodes are the sites of entry and propagation of MVV in lambs fed colostrums from infected ewes.  相似文献   

Risk of postnatal exposure to Sarcocystis neurona and Neospora hughesi in horses     

Duarte PC  Conrad PA  Wilson WD  Ferraro GL  Packham AE  Bowers-Lepore J  Carpenter TE  Gardner IA 《American journal of veterinary research》2004,65(8):1047-1052

OBJECTIVE: To estimate risk of exposure and age at first exposure to Sarcocystis neurona and Neospora hughesi and time to maternal antibody decay in foals. ANIMALS: 484 Thoroughbred and Warmblood foals from 4 farms in California. PROCEDURE: Serum was collected before and after colostrum ingestion and at 3-month intervals thereafter. Samples were tested by use of the indirect fluorescent antibody test; cutoff titers were > or = 40 and > or = 160 for S neurona and N hughesi, respectively. RESULTS: Risk of exposure to S neurona and N hughesi during the study were 8.2% and 3.1%, respectively. Annual rate of exposure was 3.1% for S neurona and 1.7% for N hughesi. There was a significant difference in the risk of exposure to S neurona among farms but not in the risk of exposure to N hughesi. Median age at first exposure was 1.2 years for S neurona and 0.8 years for N hughesi. Highest prevalence of antibodies against S neurona and N hughesi was 6% and 2.1 %, respectively, at a mean age of 1.7 and 1.4 years, respectively. Median time to maternal antibody decay was 96 days for S neurona and 91 days for N hughesi. There were no clinical cases of equine protozoal myeloenchaphlitis (EPM). CONCLUSIONS AND CLINICAL RELEVANCE: Exposure to S neurona and N hughesi was low in foals between birth and 2.5 years of age. Maternally acquired antibodies may cause false-positive results for 3 or 4 months after birth, and EPM was a rare clinical disease in horses < or = 2.5 years of age.  相似文献   

Prevalence of antibodies to bluetongue virus and Anaplasma marginale in Montana yearling cattle entering Alberta feedlots: Fall 2001          下载免费PDF全文

Van Donkersgoed J  Gertonson A  Bridges M  Raths D  Dargatz D  Wagner B  Boughton A  Knoop D  Walton TE 《The Canadian veterinary journal. La revue veterinaire canadienne》2004,45(6):486-492

A serologic survey was conducted in yearling cattle imported into Alberta feedlots from Montana during October 2001 to estimate the prevalence of antibodies to bluetongue virus (BTV) and Anaplasma marginale in Montana yearling cattle. The apparent prevalence of antibodies to BTV when the competitive enzyme-linked immunosorbent assay (cELISA) was used was 0.37% (21/5608). Test positive cELISA samples were also all positive when tested by virus neutralization (VN) and they reacted to 1 or more BTV serotypes, including 2, 10, 11, 13, and 17. The apparent prevalence of antibodies to A. marginale when a recombinant cELISA (rcELISA) was used with a positive cutoff at 30% inhibition was 1.93% (108/5608). When the rcELISA positive cutoff was at 42% inhibition, the apparent prevalence was 0.73% (41/5608). After the reported sensitivity and specificity of the test had been accounted for, the A. marginale antibody results were consistent with a population that was either free of exposure or had a very low prevalence for A. marginale.  相似文献   

Genetic parameters for various random regression models to describe total sperm cells per ejaculate over the reproductive lifetime of boars     

Oh SH  See MT  Long TE  Galvin JM 《Journal of animal science》2006,84(3):538-545

The objective of this study was to model the variances and covariances of total sperm cells per ejaculate (TSC) over the reproductive lifetime of AI boars. Data from boars (n = 834) selected for AI were provided by Smithfield Premium Genetics. The total numbers of records and animals were 19,629 and 1,736, respectively. Parameters were estimated for TSC by age of boar classification with a random regression model using the Simplex method and DxMRR procedures. The model included breed, collector, and year-season as fixed effects. Random effects were additive genetic, permanent environmental effect of boar, and residual. Observations were removed when the number of data at a given age of boar classification was < 10 records. Preliminary evaluations showed the best fit with fifth-order polynomials, indicating that the best model would have fifth-order fixed regression and fifth-order random regressions for animal and permanent environmental effects. Random regression models were fitted to evaluate all combinations of first- through seventh-order polynomial covariance functions. Goodness of fit for the models was tested using Akaike's Information Criterion and the Schwarz Criterion. The maximum log likelihood value was observed for sixth-, fifth-, and seventh-order polynomials for fixed, additive genetic, and permanent environmental effects, respectively. However, the best fit as determined by Akaike's Information Criterion and the Schwarz Criterion was by fitting sixth-, fourth-, and seventh-order polynomials; and fourth-, second-, and seventh-order polynomials for fixed, additive genetic, and permanent environmental effects, respectively. Heritability estimates for TSC ranged from 0.27 to 0.48 across age of boar classifications. In addition, heritability for TSC tended to increase with age of boar classification.  相似文献