检测砂梨潜隐病毒的IC-RT-PCR和TC-RT-PCR的研究

以砂梨为试材,在生物学和血清学检测的基础上,采用免疫捕作RT-PCR穴IC-RT-PCR雪和试管捕作RT-PCR穴TC-RT-PCR雪技术,对苹果褪绿叶斑病毒(Applechloroticleafspotvirus,ACLSV)和苹果茎沟病毒(Applestemgroovingvirus,ASGV)进行了检测分析。结果表明,TC/IC-RT-PCR均能有效检测梨粗提液中的ACLSV和ASGV,分别获得了大小约358bp和499bp的目标扩增片段;但IC-RT-PCR检测ACLSV的效果受到病毒分离株间血清学关系影响。与传统的RT-PCR相比,IC/TC-RT-PCR不仅灵敏度更高,而且不需提取总RNA,可以简化操作程序和减少苯酚、氯仿类有机试剂对人体的伤害和对环境的污染,适合于大量梨样品的病毒快速灵敏检测。     

15%苯乙锡·井可湿性粉剂防治稻曲病和稻瘟病试验与研究

近几年来,稻曲病和稻瘟病有流行加剧趋势,长期使用稻瘟灵、三环唑等常规药剂防治药效有所下降。江苏金凤凰农化有限公司研制的15%苯乙锡·井可湿性粉剂(瘟曲必克)经试验能有效地控制穗期稻曲病和稻瘟病的危害。     

香精油抗蜂螨作用的研究进展

香精油及其组分具有显著的抗螨效果。萜类化合物(主要是单萜)是香精油的主要成分。占总量的90％左右。研究者通过筛选试验测定了多种香精油及其一些组分的抗螨能力。大部分表现出良好的抗螨效果。但只有少部分在蜂群试验中表现出强抗螨能力。因此，有必要对此作进一步的研究。以达到最优化目标。同时联合其它防治手段，建立一套全面的害虫防治策略，实现蜂螨的最终控制。     

The effect of maternal obesity on fatty acid transporter expression and lipid metabolism in the full‐term placenta of lean breed swine

This study was conducted to evaluate the influence of back‐fat thickness (BF), at mating of sows, on the maternal and newborn circulating lipids, expression of placental fatty acids (FA) transporters and lipid accumulation in placenta. Full‐term placentas were obtained by vaginal delivery from BFI (9–14 mm; n = 37), BFII (15–19 mm; n = 43) and BFIII (20–27 mm; n = 38) sows according to BF at mating, and frozen placental sections were analysed for fat accumulation. Blood samples were collected from the sows of day 105 pregnancy and from cord blood at delivery. mRNA and protein expression levels were evaluated with real‐time RT‐PCR and Western blotting. Our results demonstrated that BFII females had significantly increased litter weight and placental efficiency, decreased maternal triglyceride (TG) and non‐esterified fatty acids (NEFA) levels, decreased maternal IL‐6, TNFα and leptin levels compared to BFIII females (p < .05). BFIII sows were associated with significantly decreased newborn TG levels, increased newborn glucose, IL‐6 and TNFα levels compared to BFI or BFII sows (p < .05). BFI and BFII females had significantly decreased placental TG, NEFA and cholesterol (CHOL) contents compared to BFIII females (p < .05). Moreover, decreased CD36, FATP1, FABP4, and FABP1 mRNA and protein and FATP4 protein expression, and increased LPL activity were also observed in BFIII group compared with BFII group (p < .05). PPARγ mRNA and protein and lipogenic genes such as SREBP‐1c, ACSL1, ACCα, FAS and SCD mRNA expression were downregulated or upregulated, respectively, in the placentas of BFIII sows compared to BFI or BFII sows (p < .05). Overall, this study demonstrated that there is no advantage, in terms of litter live size, litter weight and placental FA transport and metabolism, in performing the mating of sows with BF>19 mm.     

Effects of five cryoprotectants on proliferation and differentiation‐related gene expression of frozen‐thawed bovine calf testicular tissue

The cryopreservation of testicular tissue is a potential method for preserving male fertility. However, the effect of cryopreservation on bovine calf testicular tissue is scarce. This study investigated the effect of different cryoprotectants on bovine calf testicular tissue at the molecular level. Testicular tissue from ten immature bovine calves (6 months) was collected after slaughter and cryopreserved in an extender containing different concentrations of the following five cryopreservation solutions (CP): bovine serum albumin (BSA) with 5% dimethyl sulfoxide (DMSO), trehalose with 5% DMSO, DMSO and glycerol and ethylene glycol (EG). After 7‐day cryopreservation, the expression levels of three spermatogonial stem cell (SSC)‐related genes, octamer‐4 (OCT4), KIT ligand (MGF/SCF) and kit oncogene (C‐KIT), were investigated by quantitative PCR (qPCR). The cell viability was highest for the tissues preserved with 30 mg/ml BSA (77.82% ± 1.22) and 40 mg/ml trehalose (74.23% ± 1.16) compared with other groups (p < 0.05), and the level of expression of the three genes was highest with 30 mg/ml BSA (p < 0.05). Compared with other CPs, the 30 mg/ml BSA and 40 mg/ml trehalose have the better cryopreserve protection. The 30 mg/ml BSA is the most viable media for the cryopreservation of testicular tissue from cattle.     

犊牛魏氏梭菌的分离鉴定及致病性研究

2017年1月,山东省某规模化奶牛场10～20日龄犊牛出现腹泻、拉血便、呼吸困难等症状,部分犊牛突然死亡。通过流行病学调查和尸体剖检,初步怀疑为魏氏梭菌感染。采集病料进行病理组织学检查、细菌分离鉴定、生化试验、16S及毒素基因检测等,证明疫情由A型魏氏梭菌所致。对死亡犊牛的肠内容物及分离菌株进行致病性研究,发现肠内容物及分离菌株具有较强的致病性。药敏试验结果显示,该菌对青霉素、头孢噻呋、恩诺沙星等表现极敏感。根据病原确诊情况及药敏试验结果,指导临床用药,及时控制了牛场疫情。     

贮运条件对草莓主要色素成分稳定性的影响

草莓在贮藏和运输期间会产生褪色现象,花青素含量逐渐减少.为研究光照时间、温度、pH、金属离子对草莓花青素的影响,探索合适的加工与贮运条件,在花青素含量保持一致的情况下设置4种反应条件,探讨光照时间、温度、pH、金属离子对草莓花青素的影响.草莓花青素在自然光下照射8 h,吸光度值下降25％,温度高于60℃后,吸光度值下降...     

3品种工作犬幼犬警用行为测试

通过测试3品种工作犬幼犬的警用行为表现,为深入研究工作犬的品种特性,改进受训犬考评机制、提高训练的技术手段及有效建设种犬群提供数据支撑和理论依据.随机选取德国牧羊犬、昆明犬、马里努阿犬的幼犬,共计254头,测定其胆量、兴奋性及衔取等警用行为参数,以品种、品种间公母及本品种公母分组进行对比分析.结果显示,德国牧羊犬、昆明...     

基于卷积神经网络的家蚕病害识别研究

病害是我国养蚕业健康发展面临的主要威胁之一,为研究机械化养蚕模式下的家蚕病害防治方法,采用卷积神经网络进行家蚕病害图像的识别研究。首先在实际环境下,采用饲养和添食病原的方法,集中获取家蚕品种芳·秀×白·春在大蚕期的部分生长阶段下患脓病、微粒子病、白僵病、细菌病、农药中毒以及健康状态的样本,并开展图像采集工作,构建出家蚕病害图像数据集。其次采用特征融合和缩减结构的方法,对残差神经网络进行部分改进,以避免直接使用该算法会导致不必要的计算耗损。最后进行家蚕病害识别试验。结果表明:卷积神经网络能够高效准确识别家蚕病害图像,使用改进的算法在测试集上的准确率达到94.31%,与标准的残差神经网络准确率相当,但训练的参数量仅为原来的1/3,且识别效率大幅提升,更有利于网络的训练与部署。