Subjects: Biology >> Zoology submitted time 2018-12-25 Cooperative journals: 《动物营养学报》
Abstract：Klotho是一种最近发现的抗衰老基因，它的缺失或突变会导致小鼠在出生3~4周后表现出衰老现象，相反，其过表达可增强小鼠的抗氧化能力，并延长小鼠寿命。目前研究表明，Klotho蛋白发挥抗氧化应激功能可能是通过激活叉头状转录因子O（FoxO）的转录活性、激活环磷酸腺苷（cAMP）信号通路、激活Kelch样环氧氯丙烷相关蛋白-1（Keap1）-核因子E2相关因子2（Nrf2）/抗氧化反应元件（ARE）信号通路来实现的。本文就Klotho的发现、结构特征、表达及其蛋白与氧化应激之间的关系进行综述，以期为畜牧生产中缓解动物氧化应激提供思路。
Subjects: Biology >> Zoology submitted time 2018-12-24 Cooperative journals: 《动物营养学报》
Abstract：本试验旨在实测不同来源小麦的肉鸭表观代谢能（AME），并利用近红外光谱分析技术（NIRS）构建其预测模型。选用1周龄的樱桃谷肉鸭410只，随机分为41个处理，每个处理5个重复，每个重复2只肉鸭，各处理肉鸭分别饲喂玉米-豆粕型基础饲粮和40种小麦替代饲粮（含20%小麦）。用套算法计算小麦的AME，然后利用NIRS建立小麦AME的预测模型。结果表明，不同来源小麦的肉鸭AME为11.03～14.34 MJ/kg，变异系数为5.58%；小麦AME与粗纤维（CF）、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）呈极显著负相关(P<0.01)，与粗脂肪（EE）呈极显著正相关(P<0.01）。小麦AME的预测模型的定标决定系数、定标标准差和交叉验证相对标准差分别为0.85、0.187 MJ/kg和1.70%；外部验证决定系数、外部验证相对标准差和外部验证相对分析误差分别为0.89、1.46%和3.23%。由此可见，不同来源小麦肉鸭AME和化学成分含量存在差异，其AME的变异与其化学成分相关，应用NIRS预测小麦的肉鸭AME的结果“良好”。
Subjects: Biology >> Zoology submitted time 2017-10-11 Cooperative journals: 《动物营养学报》
Abstract：本试验旨在探讨硒蛋白X（SelX）基因沉默和过氧化氢（H2O2）处理对人正常肝脏细胞（LO2）中硒蛋白基因表达和抗氧化酶活性的影响，为探索SelX与其他硒蛋白之间的调控关系及SelX的功能奠定基础。对本实验室保存的SelX基因稳定沉默LO2细胞株（siSelX）和对照细胞株（CK），利用噻唑兰（MTT）法比较其生长速率；siSelX和CK用200 μmol/L H2O2处理2.5 h后，采用荧光定量PCR技术考察25个硒蛋白基因的表达量；同时比较SelX基因沉默以及H2O2处理对LO2细胞株中谷胱甘肽过氧化物酶（GSH-Px）、超氧化物歧化酶（SOD）活性及总抗氧化能力（T-AOC）的影响。结果显示：1）SelX基因沉默显著降低了LO2细胞株的生长速率（P<0.05）；2）SelX基因沉默显著上调了Gpx6、Txnrd2、Seli基因的表达量（P<0.05），显著下调了Dio2、Dio3、Selm、Sepw1基因的表达量（P<0.05）；H2O2处理显著上调了Dio1基因的表达量（P<0.05），显著下调了Gpx2基因的表达量（P<0.05）；SelX基因沉默后H2O2处理显著上调了Gpx6、Txnrd2、Dio1基因的表达量（P<0.05），显著下调了Txnrd3、Dio2、Selm、Sepw1、Selv基因的表达量（P<0.05）；3）SelX基因沉默显著提高了LO2细胞株GSH-Px活性（P<0.05），显著提高了SOD的活性（P<0.05）；SelX基因沉默后H2O2处理显著提高了GSH-Px活性（P<0.05）。由此可见，SelX基因沉默降低了LO2细胞株的生长速率，SelX基因沉默后H2O2处理影响部分硒蛋白基因在细胞中的表达量，同时也影响了GSH-Px、SOD活性。
Subjects: Biology >> Zoology submitted time 2017-10-10 Cooperative journals: 《动物营养学报》
Abstract：Nesfatin-1是新近发现的一种厌食神经肽，在中枢主要位于下丘脑和脑干，在外周主要分布于胃、肠、胰岛和性腺，其表达受到营养、生理、病理和其他摄食激素的调节。Nesfatin-1在中枢神经元和外周细胞中与多种激素协同参与摄食和血糖稳衡等能量代谢过程，并激活下丘脑-垂体-肾上腺轴（HPA）参与应激反应，还能作用于HPA影响发育期的启动。本文重点对nesfatin-1在中枢和外周的分布、影响其表达的因素以及生物学功能进行了综述。
Subjects: Biology >> Zoology submitted time 2017-10-10 Cooperative journals: 《动物营养学报》
Abstract：本试验旨在克隆、鉴定猪硒蛋白P基因（Sepp1），并探明其在猪不同组织中的mRNA相对表达量，为以猪为模型研究硒蛋白P（SelP）的功能奠定基础。根据表达序列标签（EST）序列设计引物，利用cDNA末端快速克隆（3′-RACE）技术从猪肝脏总RNA中扩增出含开放阅读框（ORF）至polyA片段，然后与EST序列进行拼接；采用荧光定量PCR技术考察Sepp1在猪9个组织中的mRNA相对表达量。结果显示：1）扩增出共1 707 bp的片段，测序后与EST拼接获得了2 109 bp的猪Sepp1序列，并提交至NCBI GenBank数据库，序列号为EF113596.2；该基因1 170 bp的ORF编码区和对应的氨基酸残基与人相应序列分别有83.72%和75.64%序列同源性，其编码390个氨基酸，含有14个硒代半胱氨酸（Sec）残基，分别位于第59、267、286、309、311、327、339、352、354、361、376、378、385和387位。2）Sepp1 mRNA在猪组织中广泛分布，在肝脏中具有最高分布，依次为甲状腺>肾脏>睾丸>下丘脑>脾脏>垂体>心脏>肌肉。本试验成功克隆、鉴定了猪Sepp1，检测了其在猪不同组织中表达分布情况，为其进一步以猪为模型探讨其功能奠定了基础。
Subjects: Biology >> Zoology submitted time 2017-10-10 Cooperative journals: 《动物营养学报》
Abstract：Kruppel样因子15(KLF15)是一种新发现的Kruppel样因子家族(KLFs)成员，为一种真核锌指蛋白转录因子。KLF15在动物体内呈现多组织表达特性，该基因过表达能促进动物脂肪沉积，且能影响肉质性状候选基因和Ⅰ型肌纤维基因的表达。因此，深入研究KLF15对脂肪沉积和肌纤维类型的影响及其可能机制，将为改善动物肉品质提供新的思路。本文综述了KLF15的发现、结构特征、表达规律及其与脂肪沉积和Ⅰ型肌纤维之间的关系。
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： With a homogeneous model of the Moon, the induced magnetic field caused by step-transient disturbation of interplanetary magnetic field is simulated by the electromagnetic induction theory. As the range of conductivity assigned, the variation from step to calm of both the vectors and magnitudes can be obtained with a fixed permeability mu_o. Then the magnetic characteristic transient response function, the field components and total field at 3 different points selected in a longitude line can all be given in different conductivities by numerical inverse Laplace transformation. The calculation provides a reasonable result that components perpendicular to the external step-transient field will disappear in a long-enough time, whereas the parallel component will become unity with it. When the external field step varies, the maximum field value which can be detected in the vicinity of the equator and the polar region are 13.65 nT and 2.71 nT, respectively. The processes of parallel component change are remarkably different in low latitude and polar region. This phenomenon reflects that magnetometers in different sites of lunar surface may lead to different field curves.
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： A kind of front-end signal processing circuit of the electric field instrument, which would be used in the Earth's magnetosphere measurement, is investigated and presented in this work. The double-probe electric field instrument outputs drive current to the ambient plasma environment, and measures the potential difference between the two probes to detect the electric field. Plasma impedance of the magnetosphere is high, so the probe of the electric field instrument will operate in a high voltage to match the electric current requirement. When the operating voltage is close to or surpasses the circuit threshold voltage, the measuring results would be affected, and the instrument will be possibly damaged. This paper adopts voltage scheme with low bias current and feedback floating power supply control scheme, to solve the weak current sampling problem and high dynamic potential handling problem in measuring the electric field of a thin plasma. Test results show that the circuit can make the probe adapt to the floating ground in the dynamic voltage range of 100 V, and measure the electric field from DC to 150kHz, with a low noise level below 14nV?mHz~(-1/2), which meets the needs of electric field measurements in magnetosphere.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-04-22
Abstract： The magnetometer based on Giant Magneto-Impedance (GMI) effect becomes one of the hottest points on magnetometer research in recent years. Compared with other magnetometers, GMI magnetometer has the advantages of miniaturization, high sensitivity, quick response, high temperature stability and low power consumption. Based on the sensitive material of Fe-based nano-crystalline ribbon, a GMI probe and subsequent signal processing circuit have been designed and realized to compose a GMI magnetometer. Experimental results suggest that in the magnetic field ranging from-25000nT to 25000nT, the sensitivity is 0.176mV穘T-1, which attains the measurement requirement of a weak magnetic field. The magnetometer has advantages of small size and low power consumption so that could be used in space magnetic field measurement.
Peer Review Status:Awaiting Review
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