Adhesion of Escherichia coli K88ab fimbriae to porcine enterocytes: effect on enzymatic activities of the brush border, and cyclic AMP and GMP levels

We have studied the cellular alterations, after in vitro adherence, of purified K88ab fimbriae to membranes of porcine enterocytes. Effects on enzymatic activities as disaccharydases and alkaline phosphatase show low changes. While cAMP levels were decreased (44%), guanylyl cyclase was increased (up to 200%), and levels of cGMP were in consequence significantly affected. This study support the role of cyclic GMP as intracellular mediator for adherence, and suggest their implication in disease, affecting a membrane-mediated mechanisms for guanylate cyclase activation, that is unique in the intestine.     

法系獭兔血液中AKP活性与体尺、体重性状的关系

对20只40日龄法系獭兔和20只68日龄法系獭兔（公、母各半）血液中AKP活性进行了测定，并分析了40日龄与68日龄法系獭兔血液中AKP活性与体重、体长、胸围的相关性。结果表明：40日龄时法系獭兔血液中AKP活性高于68日龄；日龄相同时，公兔活性显著高于母兔（P＜0.05）；40日龄AKP活性与体重有较为密切的关系，其他相关则不显著。     

Short communication: investigation of the feasibility of genomic selection in Icelandic Cattle

Icelandic Cattle is a local dairy cattle breed in Iceland. With about 26,000 breeding females, it is by far the largest among the indigenous Nordic cattle breeds. The objective of this study was to investigate the feasibility of genomic selection in Icelandic Cattle. Pedigree-based best linear unbiased prediction (PBLUP) and single-step genomic best linear unbiased prediction (ssGBLUP) were compared. Accuracy, bias, and dispersion of estimated breeding values (EBV) for milk yield (MY), fat yield (FY), protein yield (PY), and somatic cell score (SCS) were estimated in a cross validation-based design. Accuracy (r^) was estimated by the correlation between EBV and corrected phenotype in a validation set. The accuracy (r^) of predictions using ssGBLUP increased by 13, 23, 19, and 20 percentage points for MY, FY, PY, and SCS for genotyped animals, compared with PBLUP. The accuracy of nongenotyped animals was not improved for MY and PY, but increased by 0.9 and 3.5 percentage points for FY and SCS. We used the linear regression (LR) method to quantify relative improvements in accuracy, bias (Δ^), and dispersion (b^) of EBV. Using the LR method, the relative improvements in accuracy of validation from PBLUP to ssGBLUP were 43%, 60%, 50%, and 48% for genotyped animals for MY, FY, PY, and SCS. Single-step GBLUP EBV were less underestimated (Δ^), and less overdispersed (b^) than PBLUP EBV for FY and PY. Pedigree-based BLUP EBV were close to unbiased for MY and SCS. Single-step GBLUP underestimated MY EBV but overestimated SCS EBV. Based on the average accuracy of 0.45 for ssGBLUP EBV obtained in this study, selection intensities according to the breeding scheme of Icelandic Cattle, and assuming a generation interval of 2.0 yr for sires of bulls, sires of dams and dams of bulls, genetic gain in Icelandic Cattle could be increased by about 50% relative to the current breeding scheme.     

植物精油在养蜂业中的应用前景

近年来,蜜蜂种群受到多种病敌害的威胁,世界蜂群数量急剧减少,严重影响养蜂业的健康持续发展。植物精油是植物体内的一类次生代谢物质,具有杀虫、抗菌等多种生物活性。相比于其他化学药物,精油具有安全、无污染、不易产生抗药性等优点,在蜜蜂疾病防治方面有着广阔的应用前景。本文介绍了植物精油在5种重要蜜蜂病害(蜂螨、美洲幼虫腐臭病、白垩病、曲霉病和蜜蜂微孢子虫病)防治方面的研究进展。     

3%啶虫脒乳油对4种蚜虫的田间防治效果

1998～1999年在山西太原进行3%啶虫脒乳油防治棉蚜、麦蚜、菜蚜和苹果黄蚜田间小区药效试验。结果表明 ,啶虫脒对这几种蚜虫均有良好的防治效果。使用3%啶虫脒乳油0.6～0.9g(a.i.)/667m2 或10～20mg/kg稀释液 ,在蚜虫发生盛期喷雾防治 ,防治效果可达90%以上 ,持效期棉蚜、麦蚜、菜蚜可达10d以上 ,苹果黄蚜可达15d以上 ,与生产上推广使用的10%吡虫啉可湿性粉剂1.5g(a.i.)/667m2或25mg/kg稀释液防效相当。是一种理想的防治农作物蚜虫可供选择药剂     

二氯菊酸光学纯度的毛细管气相色谱法测定研究

使用以 2 ,6 -二 -O-戊基 - 3-O-丁酰基 -β-环糊精作手性固定相制成的毛细管手性柱 ,用气相色谱法在 120℃成功地分离了外消旋二氯菊酸甲酯对映体 ,其中对顺、反外消旋二氯菊酸甲酯对映体的手性分离因子分别达到 1.03和 1.04 ,均大于测定光学纯度 (e.e.% )值所要求的 1.02。测定了 4种手性二氯菊酸甲酯的光学纯度 ,方法简便易行 ,可用于二氯菊酸的光学纯度测定     

关于新疆1∶100万农业地貌区划问题的讨论

根据新疆同一地貌区域形态成因，水热及农业发展方向和改造利用条件的相似性或不同地貌区间的差异性原则，建立起构造、新构造运动、外力作用，地貌形态等农业区划樗，以及农业地貌各级区域标志。     

新疆阿克苏地区高氟地下水化学特征分析

研究区域高氟地下水的分布特征和影响因素与当地饮用水安全、地下水利用与保护息息相关。文中以阿克苏地区平原区22个地下水样为研究对象,运用数学分析及MAPGIS软件等方法从宏观上对该地区地下水F-含量的分布和影响因素进行分析。结果表明:阿克苏平原区地下水的F-质量浓度呈东、西部高,中部低分布;地下水的pH值越大,F-质量浓度越高。得出了F-质量浓度与K++Na+、Cl-、SO24-TDS、HCO3-质量浓度之间无明显相关性,与Mg2+、ρ(K++Na+)/ρ(Ca2+)之间存在着线性正相关关系,与Ca2+质量浓度之间存在着线性负相关关系的结论。并提出应对地下水高氟问题的几项对策。     

13种杀虫剂防治茶尺蠖室内药效试验

本文报道了13种杀虫剂在室内水培茶树枝条上模拟田间喷雾对茶尺蠖的药效试验。结果表明：乙基多杀菌素60克／升悬浮剂3000倍液、甲胺基阿维茵素苯甲酸盐3％微乳剂15000倍液、甲氧虫酰肼240克／升悬浮剂5000倍液、氰氟虫腙240克／升悬浮剂1500倍液．药后7d的防效均在91％以上,虫酰肼20％悬浮剂1000倍液的防效为86．48％．虽然氟虫双酰胺20％水分散粒剂6000倍液的防效稍低于上述5个处理的防效,但虫粪干重为第二少．其保叶效果仅次于乙基多杀菌素60克／升悬浮剂。因此,乙基多杀菌素60克／升悬浮剂、甲胺基阿维菌素苯甲酸盐3％微乳剂、甲氧虫酰肼240克／升悬浮剂、氰氟虫腙240克／升悬浮剂、虫酰肼20％悬浮剂、氟虫双酰胺20％水分散粒剂是比较理想的防治茶尺蠖的首选药剂．建议在茶园轮换使用。而对照药剂联苯菊酯10％乳油3000倍液对茶尺蠖的防效仅为23％．已不适合用于防治茶尺蠖。     

半巢式RT-Realtime PCR检测马铃薯Y病毒脉坏死株系

马铃薯Y病毒脉坏死株系(Potato virus Y,PVYn)是马铃薯中一个非常重要的病毒病害.本文根据PVYn基因组中RNA依赖的RNA聚合酶基因序列保守区域,设计合成了3条巢式PCR引物和1条TaqMAN荧光探针,建立了半巢式RT-Realtime PCR检测PVYn的新方法.该方法采用E.Z.N.ATM陕速提取植物总RNA,并有机地结合了巢式PCR和TaqMAN探针检测技术.第二步半巢式RT-Realtime PCR既是对第一步信号的进一步放大,也是对第一步PCR产物的确认,因此,检测的准确性、灵敏度比巢式PCR、Real time PCR等方法高.实验结果表明,该方法检测灵敏度可达4fg/μL植物总RNA.