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1.
Bovine viral diarrhea virus (BVDV) affects cattle populations causing clinical signs that range from subclinical immunosuppression to severe reproductive and respiratory problems. Detection and removal of persistently infected (PI) calves is the single most important factor for control and eradication of BVDV. Current testing strategies to detect PI calves rely heavily on immunohistochemistry (IHC) and a commercially available antigen capture ELISA (ACE) assay. These viral assays depend on 1 or 2 monoclonal antibodies which target the E(rns) glycoprotein of BVDV. The sensitivity and specificity of these two tests have been reported previously. The purpose of this research was to characterize a strain of BVDV (AU501) that was undetectable using IHC and ACE based on a single monoclonal antibody, but was consistently detected in samples from a Holstein steer using virus isolation and PCR testing. Sequencing of this AU501 viral isolate revealed a unique mutation in the portion of the genome coding for the E(rns) glycoprotein. This unique field strain of BVDV demonstrates the risk of relying on a single monoclonal antibody for detection of BVDV. Multiple testing strategies, including polyclonal or pooled monoclonal antibodies that detect more than one viral glycoprotein may be necessary to detect all PI calves and facilitate eradication of BVDV.  相似文献   
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A 13-year-old dog exhibited dramatic, radiographic osteopenia consistent with fibrous osteodystrophy secondary to primary hyperparathyroidism. Following parathyroidectomy, the dog developed severe, prolonged hypocalcemia, but was successfully treated and discharged 32 d after surgery. A variety of factors may have contributed to this dog’s hypocalcemia including hypoparathyroidism and hungry bone syndrome.  相似文献   
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对氨基酸化学发光分析法的现状和发展趋势进行了评述,其中包括氨基酸的薄层色谱和高效液相色谱化学发光分析法的基本原理以及其化学发光检测器的设计及应用(包括基于过氧化草酸盐化学发光反应的检测器,基于鲁米诺化学发光反应的检测器以及基于酶催化反应的化学发光检测器等)。  相似文献   
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Nitrate, ammonium, total dissolved nitrogen (TDN), dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) concentrations and flux were measured for one year in bulk deposition and throughfall from three stand types (upland deciduous, upland conifer and wetland conifer) on the Boreal Plain, Canada. Annual (November 2006 to October 2007 water year) flux rates in bulk deposition were 80, 216, 114 and 410 mg N m−2 for nitrate, ammonium, DON and TDN, respectively, and 3.5 g C m−2 for DOC. The nitrate and ammonium flux in throughfall were approximately 50% of the flux in bulk deposition, while TDN flux in throughfall was 60–74% of the flux in bulk deposition. The DOC flux in throughfall was approximately 2 times greater than DOC flux in bulk deposition, while there was no detectable difference in DON flux. The forest canopy generally had the most impact on throughfall chemistry during the active growing season as compared with the dormant season, although DOC concentrations in throughfall of deciduous stands was highest during autumn. For the upland stands, TDN flow-weighted mean concentrations in the snowpack were not detectably different from the concentrations in throughfall and bulk deposition throughout the rest of the year. However, ammonium concentrations were lower and DON concentrations were higher in the snowpack than in either throughfall or bulk deposition for the other seasons, suggesting some transformation of ammonium to DON within the snowpack.  相似文献   
6.
Bovine neonatal pancytopenia (BNP), a disease of neonatal calves, has been described in a number of European countries since 2006. The disease results in high mortality of calves aged 1-4 weeks and is characterised by severe bone marrow pathology resulting in profound thrombocytopenia and consequent haemorrhagic diathesis. A number of hypotheses including a novel virus infection, plant toxins, a vaccine associated isoimmune disease, or a genetic defect have been suggested to explain the aetiology of this disease. However, as the number of cases in affected herds remains small, it is hypothesised that the genetic background of the calf may influence disease susceptibility. To test this we focused on the class II region of the major histocompatibility complex (MHC) which is often associated with variations in immune response and susceptibility to antibody mediated autoimmune disease. Forty-three cases of BNP and sixty-eight controls were genotyped at the polymorphic class II MHC-DRB3 locus. Twenty DRB3 alleles were identified with seven appearing at frequencies ≥ 0.05. A comparison of the allelic frequencies between diseased and control groups showed that there was no evidence for any significant differences, suggesting that the MHC does not appear to be a predisposing risk factor in the development of BNP in Holstein dairy cattle.  相似文献   
7.
Sorghum is a critical source of food in the semiarid regions of sub-Saharan Africa and India and a potential source of dietary phytochemicals including carotenoids. The objective of this study was to determine the carotenoid profiles of sorghum cultivars, selected on the basis of their yellow-endosperm kernels, at various developmental stages. Following extraction from sorghum flours, carotenoids were separated by high-performance liquid chromatography (HPLC) with diode array detection. Total carotenoid content in fully matured yellow-endosperm sorghum kernels (0.112-0.315 mg/kg) was significantly lower (p < 0.05) than that in yellow maize (1.152 mg/kg) at physiological maturity. Variation in total carotenoids and within individual carotenoid species was observed in fully mature sorghum cultivars. For developing kernels, large increases in carotenoid content occurred between 10 and 30 days after half bloom (DAHB), resulting in a peak accumulation between 6.06 and 28.53 microg of total carotenoids per thousand kernels (TK). A significant (p < 0.05) decline was noted from 30 to 50 DAHB, resulting in a final carotenoid content of 2.62-15.02 microg/TK total carotenoids. (all-E)-Zeaxanthin was the most abundant carotenoid, ranging from 2.22 to 13.29 microg/TK at 30 DAHB. (all-E)-Beta-carotene was present in modest amounts (0.15-3.83 microg/TK). These data suggest the presence of genetic variation among sorghum cultivars for carotenoid accumulation in developing and mature kernels.  相似文献   
8.

Background  

The floral dip method of transformation by immersion of inflorescences in a suspension of Agrobacterium is the method of choice for Arabidopsis transformation. The presence of a marker, usually antibiotic- or herbicide-resistance, allows identification of transformed seedlings from untransformed seedlings. Seedling selection is a lengthy process which does not always lead to easily identifiable transformants. Selection for kanamycin-, phosphinothricin- and hygromycin B-resistance commonly takes 7–10 d and high seedling density and fungal contamination may result in failure to recover transformants.  相似文献   
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