冀西北坝上地区大蒜播种期研究

为了探讨冀西北坝上地区大蒜适宜的播种期,给当地大蒜高效生产提供理论依据,试验以大蒜品种西八里为试验材料,设置A(3月22日)、B(4月1日)、C(4月11日)3个不同播期,测定了不同播期下大蒜的生育期、植株性状、蒜头性状、蒜薹和蒜头产量等指标。结果表明,播期B和C较播期A的出苗时间分别缩短7 d和11 d;播期B的植株性状、蒜头性状均优于播期A和C,播期B一级蒜的比例最高,较播期A、C分别高出11.0和27.6个百分点;播期B较播期A和C的蒜薹产量分别提高8.41%和40.82%,蒜头产量分别提高10.19%和16.08%。本试验条件下,坝上地区大蒜适宜的播种期为3月底至清明节之间。     

Accuracy of computed tomographic arthrography for assessment of articular cartilage defects in the ovine stifle

Articular cartilage defects are one of the features of osteoarthritis in animals and humans. Early detection of cartilage defects is a challenge in clinical veterinary practice and also in translational research studies. An accurate, diagnostic imaging method would be desirable for detecting and following up lesions in specific anatomical regions of the articular surface. The current prospective experimental study aimed to describe the accuracy of computed tomographic arthrography (CTA) for detecting cartilage defects in a common animal model used for osteoarthritis research, the ovine stifle (knee, femoropatellar/femorotibial) joint. Joints in cadaver limbs (n = 42) and in living animals under anesthesia (n = 13) were injected with a contrast medium and imaged using a standardized CT protocol. Gross anatomy and histological assessment of specific anatomic regions were used as a gold standard for the evaluation of sensitivity, specificity, negative predictive value, and positive predictive value for CTA identification of articular cartilage defects in those regions. Pooled estimated sensitivity and specificity were 90.32% and 97.30%, respectively, in cadaver limbs, and 81.82% and 95.24%, respectively, in living animals. Pooled estimated positive predictive value and negative predictive values were 98.25% and 85.71%, respectively, in cadaver limbs, and 81.82% and 95.24%, respectively, in living animals. The delineation of cartilage surface was good for anatomical regions most frequently affected by cartilage defects in the ovine stifle: medial femoral condyle, medial tibial condyle, and patella. This study supported the use of CTA as an imaging technique for detecting and monitoring articular cartilage defects in the ovine stifle joint.     

西北旱区生态服务价值时空动态研究

为探明西北旱区生态服务价值的时空差异性,以2004—2012年相关数据为基础,对其生态服务价值进行计算。结果表明:(1)2012年西北旱区的生态服务价值较2004年增加了166.1×109元,而人均生态服务价值却减少了8元,说明人口的增速比生态服务价值的增速大,应适当控制人口增长;(2)西北旱区各省区生态服务价值变化大小依次为甘肃陕西中北部新疆内蒙古中西部青海宁夏,其中宁夏和青海为负变化;(3)2004—2012年间西北旱区生态经济协调度为0.33,表明生态环境和经济发展处于轻度协调状态;(4)敏感性指数小于1,说明西北旱区生态服务价值对生态价值系数弹性较弱,本文研究结果真实可信。研究期内的土地利用变化取得了较明显的生态效益,为西北旱区的经济建设和社会发展提供了良好的环境平台。     

猪流行性腹泻病毒S2基因B细胞表位嵌入型S-层蛋白在副干酪乳杆菌中的表达与鉴定

【目的】构建新型猪流行性腹泻病毒(Porcine epidemic diarrhea virus, PEDV)乳酸菌活菌疫苗载体。【方法】应用DNA重组技术将嗜酸乳杆菌S-层蛋白(SLP)基因及PEDV S2基因B细胞表位(EpitopeS2)融合基因(SLP-EpitopeS2)克隆到乳酸杆菌表达载体pTRK892中,构建重组载体pTRK-SLP-EpitopeS2,通过电转化方法将重组质粒导入副干酪乳杆菌中,获得重组副干酪乳杆菌。分别用SDS-PAGE、Western blotting和免疫荧光试验(IFA)鉴定目的蛋白在副干酪乳杆菌中的表达。【结果】PCR结果显示,成功扩增出大小为1 400 bp的目的条带,与插入融合基因大小一致,双酶切结果出现大小分别为1 400和4 700 bp的2条带,基因测序结果显示无碱基缺失和突变等,从而确定重组质粒pTRK-SLP-EpitopeS2构建正确。SDS-PAGE、Western blotting结果显示,在48 ku处出现与理论值大小一致的目的蛋白条带,表明融合基因SLP-EpitopeS2在副干酪乳杆菌中得到有效表达。IFA结果显示,...