Analysis of Drought Characteristics and Its Trend Change in Shaanxi Province Based on SPEI and MI

【Objective】 At present, most drought studies were based on historical drought events to analyze the causes and trends. This paper sought to simulate the drought index method when outputting future meteorological data based on CMIP5 model, and explored the characteristics of past and future drought changes in Shaanxi Province, which could provide a basis for the future management of agricultural water resources in Shaanxi Province. 【Method】Based on the historical data of 18 meteorological stations in Shaanxi Province and CMIP5 model, the future meteorological data were output. The reference crop evapotranspiration (ET₀) was simulated by comparing three kinds of models. The standard precipitation evaporation index (SPEI) and relative moisture index (MI) were calculated based on the reference crop ET₀ and precipitation data to reflect the drought degree. The spatial and temporal characteristics of drought in the past (1958-2017) and in the future (2018-2100) were compared.【Result】Multiple linear regression (MLR) simulation could accurately predict the reference crop ET₀ (RMSE=0.457 mm·d ^-1). In the RCP2.6 and RCP8.5 scenarios, the future drought index showed an upward trend. Under the RCP8.5 scenario, there was a sudden change in the drought index in the 1940s. The degree of drought would decrease in the future of Shaanxi Province, and the distribution of drought would be more uneven during the year. In the future, the degree of drought would decrease during summer maize growth season, and the degree of drought would increase during winter wheat growth season.【Conclusion】The characteristics and extent of drought change were different under different RCP scenarios. The changes in drought characteristics reflected by SPEI and MI were basically the same, but there were differences in the changes in some time periods. In order to effectively cope with the negative impact of climate change on dry crop yields, it was necessary to enhance soil water storage and conservation capacity, especially to strengthen drought resistance during the winter wheat growing season.     

肝片吸虫CatB4蛋白分子特征及其免疫原性分析

[目的]明确肝片吸虫组织蛋白酶B4(CatB4)的分子特征及其免疫原性,为研究肝片吸虫CatB4蛋白的生物学特性及揭示其致病机理提供科学依据.[方法]通过RT-PCR扩增肝片吸虫CatB4基因,利用在线分子生物信息学软件对CatB4基因及其编码蛋白进行分子特征分析;构建原核表达载体pET-CatB4,经IPTG诱导获得融合蛋白后进行SDS-PAGE和Western blotting检测分析;并以融合蛋白CatB4免疫小鼠制备多克隆抗体,利用免疫组化对融合蛋白在肝片吸虫体内的表达进行定位分析.[结果]肝片吸虫CatB4基因片段为699 bp,其编码蛋白等电点(pI)7.95,理论分子质量25.89 kD,无信号肽和跨膜区,属于非分泌性蛋白;CatB4蛋白存在10个潜在的磷酸化位点、2个N-糖基化位点和7个N-肉豆蔻酰化位点,有9个抗原决定簇,具有高度保守的CatB结构域,是由无规则卷曲连接9个α-螺旋和8个β-折叠构成其空间结构.基于CatB4基因核苷酸序列同源性构建的系统发育进化树显示,肝片吸虫和大片吸虫聚为一支,二者的同源性为83.98%.SDS-PAGE检测和Western blotting分析结果均显示在41.80 kD处能检测到目的条带.以纯化融合蛋白CatB4与弗氏佐剂乳化后免疫的小鼠均可产生特异性抗体,证实融合蛋白CatB4具有较强的免疫原性;免疫组化定位分析结果显示,在肝片吸虫的卵黄腺腺体细胞、排泄管上皮细胞、肠道上皮细胞和卵黄腺管上皮细胞均发生特异性的抗原抗体反应,呈深棕色.[结论]诱导表达获得的融合蛋白CatB4可特异性识别绵羊肝片吸虫阳性血清,具有较强的免疫原性,且主要在肝片吸虫分泌排泄组织器官中表达,说明CatB4蛋白具有作为肝片吸虫候选抗原的潜力.     

Serologic and molecular survey for major viral pathogens in grazing hybrid wild boars in Northeast China

Hybrid wild boar husbandry is an important component of livestock production in Northeast China. However, the current disease situation of these animals is largely unknown due to a lack of disease surveillance. The present study was conducted to determine the prevalence of several important viral diseases in the hybrid wild boar population of Northeast China. Between September 2015 to December 2016, 169 blood and 61 tissue samples were collected from apparently healthy hybrid wild boars from farms in Jilin, Inner Mongolia and Heilongjiang provinces. ELISA detected serum antibodies against classical swine fever virus(CSFV), porcine reproductive and respiratory syndrome virus(PRRSV), pseudorabies virus(PRV), porcine circovirus type 2(PCV2) and Japanese encephalitis virus(JEV), but not against African swine fever virus(ASFV), with PCV2 having the highest seropositive rate(87.2–100% in different farms). RT-PCR or PCR performed on the processed samples detected only PCV2, with 33.1%(56/169) of blood samples and 32.8%(20/61) of spleen samples being positive, respectively, indicating widespread PCV2 infection in hybrid wild boars. Phylogenetic analysis of 15 PCV2 ORF2 sequences showed that they belong to genotypes PCV2a, PCV2b and PCV2d, with nucleotide and deduced amino acid homologies of 88.5–100% and 88.1–100%, respectively.     

基于响应面分析对坚强芽胞杆菌-CX10发酵黄芪多糖的条件筛选与优化

以黄芪为原料,采用二级因子最陡上升/下降法、单因素试验和响应面法,以新分离白蚁源坚强芽胞杆菌-CX10为发酵菌种,对黄芪发酵多糖(Fermented Astragalus Polysacharin,FAPS)质量分数进行研究。对11个重要的发酵培养基因素及其发酵条件进行筛选,如化学因素(葡萄糖、蛋白胨、酵母提取物、乳清粉、KH_2PO_4、NaCl和黄芪粉)、物理因素(温度、pH和时间)和生物因素(接种量),用二阶因子(Plackett-Burman Design,PB)筛选关键因素,以发酵黄芪多糖质量分数显著性影响为中心指标,通过单因素试验考察碳源、氮源、pH、接种量、时间和温度6因素对多糖质量分数的影响,用中心复合设计(BOX-Benken Design,BBD)优化4个重要的发酵参数,如发酵pH、发酵时间、发酵温度和接种量,以获得更高的黄芪多糖的质量分数。最佳发酵条件为:pH 7.35、发酵时间37.54 h、发酵温度37.45℃、接种量10.60%。试验验证在最佳发酵条件下黄芪多糖质量分数为(69.3±0.013)%,理论预测值为71.77%,结果与预测值基本相符,证明该优化条件有效。     

宁夏石嘴山褐煤腐植酸的提取工艺

以褐煤为原料,采用碱溶酸析法提取腐植酸,考察了pH、NaOH浓度、反应温度、反应时间对腐植酸提取率的影响,并通过正交设计选择褐煤腐植酸的最佳提取条件为15g/LNaOH溶液、反应时间30 min、反应温度50℃、pH 1.0、干燥温度(60±2)℃.     

抗冻蛋白应用前景及基因工程表达研究进展

抗冻蛋白(antifreeze protein,AFP)又称为热滞蛋白,是一类抑制冰晶生长的蛋白,它具有三个基本特征:热滞效应(thermal hysteresis activity,THA)、冰晶形态效应和重结晶抑制效应(frecrystallization inhibition,RI),抗冻蛋白是一类广泛存在于鱼类、植物、真菌、昆虫中的蛋白,不同生物的AFPs的化学结构、理化性质、空间构型各不相同,并且同类生物之间的AFPs同源性也不高,不存在相似性序列或结构模式,说明它们可能是在不同的有机体中独立进化而来,没有共同的演化规律.随着研究的深入,抗冻蛋白可广泛应用于医学农学食品工业等领域,起到冷冻保护剂,食品添加剂的作用,前人已经对抗冻蛋白的结构、生化性质和抗冻机制进行了阐述,研究主要对抗冻蛋白应用方面及基因工程的表达作了系统综述,为抗冻蛋白的深入研究奠定基础.     

浅谈目前种子营销存在的问题及对策

随着市场格局的不断变化和农业种植水平的提高,人们对于种子需求在注重多样化的同时,更加关注种子的质量和产量。种子销售问题受其产品特殊性的影响,已经成为种子经营企业营销过程中迫切解决的问题。本文从种子营销存在的问题出发,探讨种子销售的策略与方法,力图为种子经营企业开展营销活动提供参考性建议。     

木荷杉木混交林水源涵养功能研究

通过野外调查和试验测定,对木荷、杉木混交林和纯林水源涵养能力进行研究。结果表明:木荷、杉木混交林地上部持水量、土壤层持水量、林分总持水量均比纯林大,均表现为木荷×杉木(6∶4)>木荷×杉木(4∶6)>木荷纯林>杉木纯林;各林分不同层次持水量为土壤层>林冠层>枯落物层>林下植被层,林分总持水量主要集中在土壤层,0～100 cm土层持水量占林分总持水量的99%以上,不同林分土壤层持水量差异主要在0～40 cm,60～100 cm土壤层持水量差异较小。混交林水源涵养功能大于纯林。     

核磁共振技术在枯草芽孢杆菌的抗菌物质结构鉴定中的应用

核磁共振(NMR)技术是化合物结构鉴定的一种重要的方法。该文简单介绍了NMR技术的基本原理,及NMR技术在枯草芽孢杆菌所产的多肽、脂肽类抗菌物质结构鉴定中的运用概况,进一步阐述了NMR联用技术的发展现状,展望了其在枯草芽孢杆菌抗菌物的结构鉴定方面的应用前景。