三化性桑蟥自然种群数量动态分析

采用生命表的形式研究了三化性桑蟥自然种群数量动态规律。通过计算各世代I值和IPC值 ,并进行组分分析证明 ,在自然环境中桑蟥的种群控制指数较低 ,繁殖率、生命率很强。种群增长虽然各世代有所区别 ,但I值都在 11以上 ;第 2代桑蟥的世代周期短 ,增长指数大 ,环境控制能力弱 ,容易蔓延 ,造成第 3代桑蟥迅速增长 ,形成灾害性危害。     

管道线路纵断面图设计软件简介

管道线路纵断面图设计是管道设计的重要内容之一，该图是指导施工、运行维修的主要依据。纵断面图设计时考虑的因素较多、对比方案多，计算繁杂、效率低、质量不易保证、设计周期长。用计算机进行该项设计，是改变这种状况的有效途径。“管道线路纵断面图设计软件”共有４个功能模块，主要用于埋地敷设的钢质压力管道的纵断面设计。该软件能迅速、准确地进行纵断面图的设计。通过在管道设计中的应用，说明其工效高、图纸整洁、线条清     

外源和内源性cAMP对猪肥育期脂质和蛋白质沉积的影响

给猪皮下注射cAMP或氨茶硷,并对肥育猪的胴体组成、肉中生化物质及血液中诸生化成分进行分析,结果表明,cAMP和氨茶硷分别使瘦肉率提高8.73%和16.13%,眼肌面积提高29.58%和21.53%,后腿比提高6.84%和10.18%;cAMP还使背膘厚降低24.67%(p<0.05);肉中脂肪降低25.80%和7.70%,血糖分别增加12.27%和32.20%(p<0.01),血蛋白质增加12.43%和18.31%;且非蛋白氮下降,血脂分别增加12.44%和4.55%,脂肪酶活性增加34.74%(p<0.05)和16.28%;血脂升高与脂肪酶活性升高呈正相关,同时血中cAMP均增加1倍以上,cGMP也有相应的升高趋势.     

玉米理化品质及其鸡代谢能的变异研究

试验测定了55个玉米样品的理化指标和鸡代谢能以评定玉米的营养价值变异。将28日龄体重相近的AA肉仔鸡随机分为不同处理组,每组8个重复,每个重复8只鸡。试验包括1个基础日粮组及待测玉米替代组,添加0.4%TiO2作为外源指示剂。收集32～35日龄排泄物,测定玉米样品的AME和AMEn。结果显示,玉米粗脂肪、粗灰分、酸性洗涤纤维和直支比的变异系数分别为10.35%、12.32%、11.33%和13.51%,其余理化指标变异系数在10%以内。玉米AME和AMEn的变异系数分别为5.97%和5.78%,且不同来源玉米代谢能存在显著差异。从相关性分析结果看,玉米代谢能的差异主要由玉米总能、中性洗涤纤维、酸性洗涤纤维和总淀粉含量的差异所致。     

环介导恒温扩增(LAMP)-检测沙门氏菌

建立一种能够快速准确地检测沙门氏菌的LAMP方法。根据沙门氏菌invA基因设计了引物,然后进行LAMP反应条件的优化、特异性试验,通过LAMP与PCR灵敏度的试验与实际样品进行检出率的比较。LAMP方法特异性好,最佳反应温度为63℃,只对沙门氏菌进行扩增;沙门氏菌的检测灵敏度为7～8cfu/mL。LAMP方法检测沙门氏菌特异性强、灵敏度高、时间短且操作简便,有望成为快速检测沙门氏菌的新方法。     

Expression and antigenicity characterization for truncated capsid protein of porcine circovirus type 2

Three pairs of specific primers were designed to amplify F2-1, F2-2, and XF2-2 truncated capsid protein genes of porcine circovirus type 2 (PCV-2). Amplified sequences were subcloned to pET-32a(+) vectors and expressed in Rosetta (DE3) Escherichia coli by induction of isopropy-β-D-thiogalactoside (IPTG). All of the fusion proteins had positive reactions to PCV-2 antiserum and His-XF2-2 showed the best reactivity. Proteins were used to immunize BALB/c mice to produce monoclonal antibodies (mAbs), and 7 mAbs were selected. Capsid protein N-terminal parts 55 to 96 amino acid (aa), 97 to 141 aa, and 143 to 211 aa were confirmed as binding regions of the 7 mAbs. Reactivity between His-XF2-2 and the 7 mAbs was detected, FmAb-8 showed the best reactivity. The dominant B-cell epitope was located at 97 to 141 aa. The PEPSCAN indicated that the P122-136 peptide contained the dominant B-cell epitope.     

保水剂对土壤孔隙影响的定量分析

为探明保水剂不同用量对施入土层土壤孔隙特征及其分布的影响,采用CT扫描法研究盆栽试验条件下小麦收获时的土壤孔隙特征。结果表明:1)施用保水剂均提高了土壤剖面不同土层的土壤孔隙数目、孔隙度和孔隙成圆率。2)随保水剂用量的增加,各土层平均总孔隙数、总孔隙度及成圆率提高;但保水剂用量过高,其总孔隙数增加不明显,总孔隙度和孔隙成圆率降低,但仍高于对照(CK)。3)最终的小麦生物量和籽粒产量表现为54 mg/kg>81 mg/kg>27 mg/kg>CK。因此,施用保水剂改善了土壤孔隙特征,促进了小麦的生长和产量的提高。各处理中以54 mg/kg保水剂用量对于小麦生物量及产量的提高最为显著,分别较对照提高13.1%和22.2%。     

Impacts of 22-year organic and inorganic N managements on soil organic C fractions in a maize field,northeast China

Impacts of 22-year organic and inorganic N managements on total organic carbon (TOC), water-soluble organic C (WSOC), microbial biomass C (MBC), particulate organic C (POC) and KMnO₄ oxidized organic C (KMnO₄-C) concentrations, C management index (CMI), and C storage in surface soil (0–20 cm) were investigated in a maize (Zea may L.) field experiment, Northeast China. The treatments included, CK: unfertilized control, M: organic manure (135 kg N ha^− 1 year^− 1), N: inorganic N fertilizer (135 kg N ha^− 1 year^− 1) and MN: combination of organic manure (67.5 kg N ha^− 1 year^− 1) and inorganic N fertilizer (67.5 kg N ha^− 1 year^− 1). TOC concentration and C storage were significantly increased under the M and MN treatments, but not under the inorganic N treatment. The organic treatments of M and MN were more effective in increasing WSOC, MBC, POC and KMnO₄-C concentrations and CMI than the N treatment. The M treatment was most effective for sequestrating SOC (10.6 Mg ha^− 1) and showed similar increase in degree of grain yield to the N and MN treatments, therefore it could be the best option for improving soil productivity and C storage in the maize cropping system.     

Effect of Elevated Ultraviolet-B Radiation on Microbial Biomass Carbon and Nitrogen in Barley Rhizosphere Soil

As one of the important problems in global change, elevated ultraviolet-B (UV-B) radiation induced by the depletion of stratospheric ozone layer has received more and more attentions around the world. Field experiment with barley was conducted to investigate the effects of elevated UV-B radiation on microbial biomass carbon and nitrogen in rhizosphere and nonrhizosphere soil. The experiment was designed with two UV-B radiation levels, i.e., elevated (E, simulating 25% stratospheric ozone depletion) and ambient (A, control), and performed at the Station of Agricultural Meteorology, Nanjing University of Information Science and Technology, Nanjing, China. Compared with the control, elevated UV-B radiation significantly depressed shoot biomass by 13.2?C42.6% and root biomass by approximately 50% from jointing to ripening stage. Elevated UV-B radiation significantly increased microbial biomass C and N in nonrhizosphere soil in most cases, but significantly decreased microbial biomass C and N in rhizosphere soil. Further researches are needed to elucidate whether the above findings are connected with the changes in composition and amount of root exudates induced by elevated UV-B radiation, which can mainly affect the dynamics of soil microbial biomass.