Genetic diversity and relationship of Yunnan native cattle breeds and introduced beef cattle breeds

In this study, random amplified polymorphic DNA (RAPD) analysis was used to estimate genetic diversity and relationship in 134 samples belonging to two native cattle breeds from the Yunnan province of China (DeHong cattle and DiQing cattle) and four intro

Molecular characterization of beef liver catalase by scanning tunneling microscopy

Beef liver catalase molecules can stick tenaciously to the highly oriented pyrolytic graphite (HOPG) surface which has been activated by electrochemical anodization. The immobilized sample is stable enough for high resolution scanning tunneling microscope (STM) imaging. When the anodized conditions are controlled properly, the HOPG surface will be covered with a very thin oxide layer which can bind the protein molecules. Individual molecules of native beef liver catalase are directly observed in detail by STM, which shows an oval-shape structure with a waist. The dimensions of one catalase molecule in this study are estimated as 9.0 x 6.0x 2.0 nm(3), which are in good agreement with the known data obtained from X-ray analysis, except the height can not be exactly determined from STM. Electrochemical results confirm that the freshly adsorbed catalase molecules maintain their native structures with biological activities. However, the partly unfolding structure of catalase molecules is observed after the sample is stored for 15 days, this may be caused by the long-term interaction between catalase molecules and the anodized HOPG surface.

脂肪酸钙对放牧肉牛超数排卵效果及雌二醇和孕酮水平的影响

以探讨添加脂肪酸钙对放牧肉牛(婆罗门和BMY)超数排卵效果及血中雌二醇(E2)和孕酮(P4)水平的影响为目的.将48头供体分为Ⅰ(放牧或对照组)、Ⅱ(放牧+浓缩饲料500 g/d)和Ⅲ(放牧+浓缩饲料500 g/d+脂肪酸钙100 g/d)3组,从同期发情处理开始到冲胚结束试验期32 d,并对供体牛在8个处理时段进行采血,用放射免疫分析法(RIA)分析E2和P4水平.试验结果表明:Ⅰ,Ⅱ,Ⅲ组供体牛超数排卵的排卵率分别为75.4%,74.4%和81.7%(P＞0.05),受精率分别为81.4%,55.6%和93.2%(P＞0.05);获胚(卵)数分别为7.0枚,6.3枚和7.3枚(P＞0.05),可用胚数分别为3.9枚,2.6枚和4.7枚,Ⅲ组显著高于Ⅱ组(P＜0.05);E2平均水平分别为0.57 pg/mL,0.47 pg/mL和0.63 pg/mL(P＞0.05),P4平均水平分别为3.53 ng/mL,5.03 ng/mL和3.74 ng/mL,Ⅱ组高于Ⅰ,Ⅲ组(P＜0.01).表明适量添加脂肪酸钙能改善全放牧肉牛的营养、增强体质,促进排卵与受精,增加超数排卵的可用胚数;能使供体牛的E2和P4水平比对照组有所提高;添加效果冬、春季优于夏、秋季.