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排序方式: 共有67条查询结果,搜索用时 62 毫秒
31.
用免疫组化SP法检测了去势及去势后补充雄激素大鼠脊髓灰质缘核中雄激素受体(Androgen receptors,AR)蛋白的表达情况,以探讨雄激素对缘核的作用。结果表明,睾丸摘除组大鼠缘核内AR蛋白的表达和睾丸摘除并用睾酮替代组大鼠缘核内AR蛋白的表达接近。说明去睾丸大鼠阻断其内源性雄激素后,对缘核AR蛋白表达影响甚小,而补充外源性雄激素对此影响不大。 相似文献
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Abstract AIM: To monitor changes in concentrations of lolitrem B and epoxy-janthitrems in the fat of sheep grazing perennial ryegrass infected with wild-type- and AR37-endophyte, respectively, during the time of year when ryegrass staggers would be expected to be observed. METHODS: Ten 5-month-old lambs with no previous exposure to endophytes were grazed on either wild-type (containing lolitrem B, n = 5) or AR37 (containing epoxy-janthitrems, n = 5) endophyte-infected perennial ryegrass (Lolium perenne L.) pastures between October 2008 and June 2009. Animals were regularly assessed for ryegrass staggers using the Keogh scale (0 = no signs, 5 = severe tremors). When a score of > 3.5 was observed animals were removed from the treatment pastures for 1 month. Fat biopsy samples were taken from each animal at approximately monthly intervals and analysed for endophyte metabolites using high performance liquid chromatography (HPLC) methods developed during this study. Regular herbage samples were also taken and concentrations of endophyte metabolites measured. RESULTS: Efficient and reproducible methods to analyse both lolitrem B and epoxy-janthitrems in fat were developed. Concentrations of lolitrem B and epoxy-janthitrems in herbage and in sheep fat increased from late November to peak in mid-February. Ryegrass staggers was observed in both groups of sheep at this time. Following 1 month of grazing non-infected pasture mean concentrations in fat of lolitrem B decreased by 43% from 61.8 to 35.3 ppb, and of epoxy-janthitrems by 38% from 1032.0 to 639.5 ppb. Maximum concentrations in herbage of epoxy-janthitrems (35.7 ppm) were higher than of lolitrem B (3.4 ppm), but signs of staggers were less severe in sheep grazing pasture containing the former compared with the latter (median Keogh scores in late February were 2 and 3, respectively), consistent with epoxy-janthitrems being low potency toxins. CONCLUSION: This study demonstrated that concentrations of epoxy-janthitrems and lolitrem B in sheep fat increased quickly during the initial phase of the study when concentrations in pasture increased, and decreased when animals were removed from pastures containing these compounds. These data will be used in the risk assessment of the endophyte metabolites. 相似文献
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针对时间序列分布特征多样性的问题,不考虑序列本身的分布特征而选择非对称Laplace分布的似然函数对模型进行贝叶斯分位回归分析.利用Metropolis-Hastings算法模拟参数的后验边缘分布,解决了参数估计过程遇到的高维数值积分的问题.仿真分析中,参数的迭代轨迹是收敛的,说明MH抽样有效地模拟了参数的后验边缘分布;并且应用该方法估计出了不同分位数下模型参数的后验均值,标准差,MC误差和95%的置信区间.非对称和局部持续性数据的数值模拟,证实了贝叶斯分位自回归模型可以更全面有效地描述滞后变量对响应变量变化范围和条件分布形状的影响. 相似文献
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油棕新品种遗传多样性的ISSR分析(摘要)(英文) 总被引:1,自引:0,他引:1
[目的]从DNA分子水平上对油棕新品种进行遗传多样性的分析,旨在为这些新选育油棕种质的开发利用提供分子水平的理论依据。[方法]采用改良的CTAB法提取油棕叶片总DNA。从加拿大哥伦比亚大学所设计的60个引物在部分模板中进行筛选,筛选出能扩增出多态性的引物23个用于样品的进一步分析。通过一定的摸索实验,最终确定用于油棕的各个组分的ISSR最佳反应体系。优化反应体系总体积为15.00μl,各个组分的具体用量为:MgCl2(25mmol/L)+10×Buffer2.25μl、dNTP(10mmol/L)0.30μl、Taq酶(5U/μl)0.15μl、引物(0.4μmol/μl)1.00μl、模板DNA(50ng/μl)1.00μl、ddH2O(超纯水)10.30μl。PCR扩增程序为:94℃预变性4min,然后94℃变性1min,52℃退火1min,72℃延伸1min,35个循环,72℃保温10min,4℃保温。采用2%琼脂糖凝胶电泳,EB染色检测扩增产物。ISSR数据的统计分析方法:每个样品的扩增产物电泳分离谱带在某一位点上按有或无记录,存在时赋值为"1",无带的记为"0"。将每个引物对所有样品的读带记录结果形成"0-1"矩阵。用NTSYS-pcversion2.1计算Jaccard’s相似系数,在此基础上用非加权类平均聚类法(UPGMA)进行聚类分析,绘制亲缘关系树状图。[结果]用23个引物共扩增得到201条扩增条带,其中多态性条带占41.8%。根据ISSR遗传相似系数按UPGMA法聚类,以所有材料间的平均遗传相似系数0.838为阈值,可将其明显的划分为2大类:采自海南的R1~R12新种质材料与采自云南的V20新种质材料合为一类;采自云南其余的新种质材料为一类。用NTSYS-pc软件所得出的主成分分析图也能够明显的将海南和云南引进的新油棕种质材料区分开来,海南的R1~R12油棕与云南的V20油棕基本上归为一类;与聚类图不同的是,云南的新油棕种质V15、V16、V17、V19、V21、V22基本上归为一类,而品种V13、V14与V18则较远一些。[结论]海南与云南新选育的油棕种质材料可能来源于不同的国家或地区。 相似文献
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Total alkylresorcinol (AR) content and homologue composition were assessed in whole grain flours of 15 varieties each of bread wheat, durum, spelt, emmer, and einkorn grown in four different environments. Bread wheat (761 ± 92 μg/g DM) and spelt (743 ± 57 μg/g) belonging to the hexaploid species showed higher AR concentrations than the tetraploid durum (654 ± 48 μg/g, p < 0.05), while the concentrations found in the diploid einkorn (737 ± 91 μg/g) and the tetraploid emmer (697 ± 94 μg/g) did not significantly differ from the other species. The AR content showed a remarkable heritability and, thus, seemed to be mainly determined by genetic factors. If ARs were assumed to be deposited within a specific AR-rich layer of the kernel, AR levels of all varieties would easily surpass their minimal inhibitory concentrations against fungal pathogens within this barrier layer. Although the AR carrying a C21:0 side chain was the main homologue in all species, the levels of all AR homologues and their relative composition significantly differed between hexaploid (bread wheat and spelt), tetraploid (durum and emmer) and diploid (einkorn) species. Consequently, a clear-cut differentiation of Triticum species and derived whole grain flours according to their degrees of ploidy was established based on concentrations of saturated C17-, C19-, C21-, C23-, and C25-substituted ARs. 相似文献
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使用隔夜拆借利率数据为样本,利用模型对SHIBOR市场利率的动态特性进行研究.研究结果表明:首先,SHIBOR隔夜拆借利率存在条件异方差性;其次,所使用的AR(1)-GARCH(1,1)模型能够很好地刻画SHIBOR隔夜拆借利率序列的自相关性和条件异方差现象,进而可以准确地对其波动性进行估计和预测;再次,SHIBOR市场隔夜拆借利率的变动与其前一期利率的变动关系十分紧密,而隔夜拆借利率波动受前一期利率波动的影响很大,具有很强的持续性. 相似文献
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本实验室从土壤中筛选出一株对烟草青枯病有较强防治作用的芽孢杆菌AR03菌株。通过正交试验,对其发酵培养基进行优化,并且对发酵条件(起始pH值、装液量、接种量、温度、转速、最佳发酵时间)进行了研究。结果表明,不同的发酵培养基组分对菌体收获重量的影响相差较大,其中牛肉膏影响最大。本试验获得的最佳摇瓶发酵配方为(质量分数):牛肉膏0.9%、蛋白胨1.5%、葡萄糖1%、NaCl 0.5%。最适发酵条件为:发酵起始pH值为7.3,300ml的三角瓶装瓶量为60ml,接种量为8%,温度为31℃,转速为140r/min,发酵时间为36h。 相似文献
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