ONCHOCERCA GUTTUROSA IN Danish cattle. Prevalence, geographic distribution and host-vector relationships.

1. Onchocerca gutturosa is reported in Danish cattle for the first time. Microfilariae were found in 38 (9.4%) of 406 cows that were 2 years or older.
2. Microfilariae were not randomly distributed throughout the skin but were concentrated in the umbilical area.
3. No difference in prevalence was observed between breeds of cattle.
4. Most of the infected cows had grazed on fields close to streams that contained Simulium ornatum, the vector of O. gutturosa.
5. Differences in preferred biting sites of S. ornatum from cow to cow were correlated with the arrangement of hair.

     

基于NGO-CNN-SVM的高标准农田灌溉工程施工成本预测

为提高高标准农田项目施工成本的预测精度,控制施工成本在合理范围,减少投资风险,该研究从单体灌溉工程施工成本预测角度出发,通过随机森林（random forest,RF）筛选出高标准农田灌溉工程施工成本的关键影响因素,结合卷积神经网络（convolutional neural networks,CNN）和支持向量机（support vector machine,SVM）两种模型的优点,通过北方苍鹰优化算法（northern goshawk optimization,NGO）对模型里的惩罚因子和核参数进行寻优,构建基于NGO-CNN-SVM的施工成本预测模型。通过辽宁省2018—2023年高标准农田工程中灌溉工程的施工成本数据,选取样本决定系数R²、平均绝对误差MAE、平均绝对百分比误差MAPE和均方根误差RMSE作为精度指标进行分析,结果表明：基于NGO-CNN-SVM的施工成本预测模型在渠道工程中MAE低于0.615万元,RMSE低于0.512万元,R²达到0.968以上,相对误差小于4.210%;在进水闸工程中MAE低于0.610万元,RMSE低于0.536万元,R²达到0.966以上,相对误差小于4.410%;在桥涵工程中MAE低于0.494万元,RMSE低于0.477万元,R²达到0.970以上,相对误差小于3.548%,并相比较于反向传播神经网络,CNN和CNN-SVM模型,NGO-CNN-SVM模型的预测结果均最优。通过特征选择、模型融合、算法优化以及不同模型对比表明NGO-CNN-SVM模型具有更高的预测准确率和泛化性,可为高标准农田灌溉工程施工成本预测提供理论依据。     

蚯蚓纤溶酶基因番茄表达载体的构建

为研究蚯蚓纤溶酶的番茄表达,构建EFE基因的番茄表达载体pF和pEF,并导入农杆菌。采用PCR法在EFE基因DNA序列上添加了表达调控元件和酶切位点后,得到新EFE基因片段,将该片段与切去GUS基因的pBI121载体相连,以构建CaMV35S驱动的EFE组成型表达载体pF;用PCR克隆得到的E8启动子片段替换pF上的35S启动子,以构建番茄成熟果实特异性表达载体pEF;最后,采用三亲交配法用重组质粒转化根癌农杆菌EHA105;结果表明:经过酶切、PCR和测序鉴定,EFE基因、E8启动子序列已重组到表达载体上,植物表达载体构建正确,并且已经转化进农杆菌EHA105中。     

小菊'类锌指蛋白'基因植物表达载体构建及对烟草的转化

为了建立耐盐碱小菊(Chrysanthemum morifolium)中克隆到的'类锌指蛋白基因'CmSTZF(DQ864730)的烟草遗传转化体系,并研究其抗逆特性。本研究借助Gateway技术构建了小菊'类锌指蛋白'基因CmSTZF的过量表达载体pH7WG2D-CmSTZF,并以烟草NC89(N.plumbaginifolia'NC89')的叶片为试材,通过农杆菌介导的转化,成功地建立了烟草遗传转化体系,经PCR-Southern鉴定获得CmSTZF的转基因烟草株系。     

慢病毒载体构建策略及生物安全性研究进展

慢病毒可以感染分裂细胞和非分裂细胞,是较有前途的病毒载体,来源于HIV-1型载体,能阻止形成有复制能力的HIV-1病毒,构建一个更为安全的模式是慢病毒载体构建策略的焦点。该文介绍了慢病毒载体应用过程中的不同载体系统及构建策略,对载体的生物安全性进行了分析,展望了慢病毒在基因治疗、RNA干扰及转基因领域的应用前景。     

苦瓜MAP30基因的克隆与载体构建

首先提取苦瓜的基因组DNA,然后根据Genbank中已公开发表的MAP30序列,设计一对特异引物MAP301,MAP302,并增添特异定位于内质网的小肽Kozak序列。采用PCR技术,从苦瓜的基因组DNA中扩增出一分子量为800bp左右的片段,回收克隆测序,结果表明,克隆获得片段与已公开发表的MAP30序列同源性达100%,将阳性克隆进行酶切,获得的目标片段与用同样酶切所获得的植物表达载体pEV1和pEV2大片段连接,酶切鉴定重组子构建成特异表达于果实的载体。     

含PRRS病毒ORF5的伪狂犬病病毒TK基因缺失转移载体的构建

提取伪狂犬病病毒（ＰＲＶ）ＢａｒｔｈａＫ６１株基因组ＤＮＡ,用限制性内切酶ＫｐｎＩ充分消化,回收５．９ｋｂ片段（Ｊ片段）,将其克隆于质粒ｐＵＣ１１９ ＫｐｎＩ位点上,获得ｐＢＫＪ。用两对针对ＰＲＶ ＴＫ基因的特异性引物对重组质粒进行ＰＣＲ鉴定,证明其中含有ＰＲＶ ＴＫ基因。然后用ＫｐｎＩ、ＰｓｔＩ和ＢａｍＨＩ等限制性内切酶对其进行酶切分析,确定了克隆片段的物理图谱。进一步研究证实ＴＫ基因位于其中的     

H9N2亚型禽流感病毒NS1基因真核表达载体的构建及其在293细胞瞬时表达

在293细胞中瞬时表达A/Chicken/Henan/1001/2010（H9N2）NS1基因蛋白,并对表达蛋白活性进行测定。试验利用PCR技术从NS1-T载体质粒上扩增NS1基因,将其克隆至pCAGGS载体,构建重组质粒NS1-pCAGGS;经酶切和测序鉴定正确后,重组质粒NS1-pCAGGS与脂质体按照一定比例混合后转染293细胞,用间接免疫荧光方法对瞬时表达细胞进行荧光信号反应。结果显示,禽流感NS1基因可以很好地在293细胞中瞬时表达,具有良好的反应原性。     

安徽省蓝舌病流行病学调查

１９８７～１９９１年，安徽省的三个县发生了绵羊的蓝舌病，并经病毒分离、鉴定证实。绵羊的发病率为３３．０％，病死率１１．３％。对反刍家畜的血清学调直显示，疫区中的阳性率高于非疫区。黄牛、水牛、绵羊的阳性率无统计学差异，均明显高于山羊及乳牛；美利奴绵羊的阳性率高于考力代及罗姆尼；放牧羊群的阳性率高于舍饲；无明显的年龄差异。调查得本省库蠓１２种，尖喙库蠓、原野库蠓及日本库蠓为本省嗜畜的优势种。分析认为：原野库蠓是最可疑的媒介昆虫，水牛、黄牛是本省蓝舌病病毒越冬的保毒宿主。     

Epizootic haematopoietic necrosis virus—An assessment of the likelihood of introduction and establishment in England and Wales

Epizootic haematopoietic necrosis virus (EHNV) is an iridovirus that affects perch (Perca fluviatilis) and rainbow trout (Oncorhynchus mykiss). It emerged in Australia in the 1980s and has not been discovered elsewhere. It causes a high level of mortality in perch resulting in steep population declines. The main possible routes of introduction of the virus to England and Wales are the importation of infected live fish or carcasses. However, no trade in live susceptible species is permitted under current legislation, and no importation of carcasses currently takes place. The virus is hardy and low levels of challenge can infect perch. Therefore, mechanical transmission through the importation of non-susceptible fish species should be considered as a potential route of introduction and establishment. Carp (Cyprinus carpio) have been imported to the UK from Australia for release into still-water fisheries. A qualitative risk assessment concluded that the likelihood of EHNV introduction and establishment in England and Wales with the importation of a consignment of carp was very low. The level of uncertainty at a number of steps in the risk assessment scenario tree was high, notably the likelihood that carp become contaminated with the virus and whether effective contact (resulting in pathogen transmission) is made between the introduced carp and susceptible species in England and Wales. The virus would only establish when the water temperature is greater than 12 °C. Analysis of 10 years of data from two rivers in south-west England indicated that establishment could occur over a period of at least 14 weeks a year in southern England (when average water temperature exceed 12 °C). Imports of live fish from Australia need to be evaluated on a case-by-case basis to determine which, if any, sanitary measures are required to reduce the assessed risk to an acceptable level.