自体或异体小鼠卵丘细胞核移植胚胎的发育

体细胞核移植胚胎发育到成体和许多因素有关,如供体细胞的种类(Wakayama et al.,2005;Saito et al.,2004),性别和基因型(Wakayama et al.,2005),线粒体(Bruggerhoff et al.,2002)等.供体细胞核在卵胞质因子作用下重编程,抑制自身基因表达,恢复为胚胎发育所必需的基因表达状态.本研究比较了来自同一雌鼠(SI)或者不同雌鼠(DI)的供体细胞对核移植胚胎的发育影响.     

Microbial diversity assembled from series-diluted suspensions of disease-suppressive soil determines pathogen invasion resistance

Dear Editor,Soil microbial biodiversity loss caused by agricultural intensification, climate change, and the application of chemical fertilizer has become a serious problem that threatens humans (Wall et al., 2015). One phenomenon responsible for economic and food security issues is soil-borne diseases(Fisher et al., 2012), which were reported to be associated with microbial diversity loss (Shen et al., 2013;Fu et al.,2017).     

Ultraviolet B radiation-mediated stress ethylene emission from rice plants is regulated by 1-aminocyclopropane-1-carboxylate deaminase-producing bacteria

Dear Editor,Industrial emissions have played a major role in damaging the ozone layer,leading to increased atmospheric penetration of ultraviolet B (UV-B)(290–320 nm) radiation (Jordan,2002).The recovery rate of the damaged ozone layer in the mid-latitudes and tropics has been insignificant since 1979(Chipperfield et al.,2017),even after the adoption of the Montreal Protocol (Protocol,1987),and the recovery process is expected to take many decades.In the meantime,UV-B radiation continues to penetrate the atmosphere (McKenzie et al.,2011;Bais et al.,2019).The characteristic short length and high energy of this radiation wavelength can directly affect major molecules,such as DNA,proteins,and lipids,which are important to living beings (Hideg et al.,2013).Rice is one of the major global crops,which is generally cultivated at lower latitudes and can potentially be exposed to a higher flux of UV radiation due to greater solar angles and longer duration of sunlight (Kataria and Guruprasad,2012).     

克氏杆菌gldA基因亚克隆及其原核表达载体构建

甘油脱水酶(glycerol dehydratase EC 4．2．1．30)是控制甘油分解和产生1，3-丙二醇的关键性限速酶。甘油脱水酶是由α、β和γ3个亚基组成的复合物(α2β2γ2)，分别由gldA、gldB和gldC基因编码。研究(Frank et al.1998;Macis et al.,1998;Markus et al.,1996)认为甘油脱水酶α亚基无论在甘油脱水酶的结构上还是功能上都起到重要的作用。本研究克隆了克氏杆菌的甘油脱水酶α亚基基因(gldA)并构建了该基因的原核表达载体，为甘油脱水酶基因的进一步表达研究及探索其作用机制奠定了基础。     

Drying-rewetting rather than sieving stimulates soil respiration

Dear Editor,Soils contain the largest carbon(C) pool in terrestrial ecosystems.Even a small change in soil C pool may significantly influence atmospheric carbon dioxide(CO₂) concentration.Thus,it is critical to accurately assess the response of soil C pool to global change.Soil incubation is a frequently used method to assess soil C decomposition rate because it allows environmental variables to be under control(Unger et al.,2010;Shi and Marschner,2014).However,pre-treatments during soil sampling and processing,such as sieving and drying-rewetting,inevitably bring physical disturbances which may affect soil respiration rate(Franzluebbers,1999;Thomson et al.,2010;Curtin et al.,2014).     

玉米Ubi-1启动子驱动挪威鼠热激蛋白4基因（Hspa4）植物表达载体的构建

挪威鼠热激70 kD蛋白4(Rattus norvegicus heat shock protein 4,Hspa4)是哺乳动物细胞内重要的一种分子伴侣,通过参与热激响应、未折叠蛋白应答等来保护机体免受损伤,在适应外界应答时是一种关键性的蛋白质(Kang et al.,2002;Zhao et al.,2007),有阻止蛋白质变性的功能.本研究选用在单子叶植物中活性极强的玉米Ubi-1启动子,构建了可持续、高效表达挪威鼠Hspa4基因的组成型单子叶植物表达载体pCAMBIA1301-Ubi-Hspa4(p13UH),为利用Hspa4提高植物的抗逆性提供资料.     

结球甘蓝转录调控肿瘤蛋白基因（TCTP）的分离与表达特性初步分析

TCTP（translationally controlled tumor protein）是许多动物肿瘤细胞中存在的一类较丰富的蛋白（Yenofsky et al.1983），目前为止，有关TCTP的确切功能还不是很清楚，推测TCTP可能是属于对热较为稳定的钙结合蛋白（Kim et al．，2000），能够结合微管蛋白（Gachet et al．，1999），诱导细胞内的信号传递（MacDonald et al．,1995），同时细胞增殖有关（Bohm et al.,1989）。     

粘虫痘病毒增效蛋白的重组表达及其生物活性

昆虫病毒增效蛋白(enhancin)在体外能促进核型多角体病毒(NPV)对昆虫离体细胞系的感染;在体内能显著提高NPV对昆虫幼虫的感染效果,并可增强苏云金芽孢杆菌(Bt)对幼虫的毒力(Hashimoto et al.,1991;Roelvink et al.,1995)。粘虫痘病毒(Pseudaletia separata entomopoxvirus,PsEP     

Overall benefits of biochar, fed to dairy cows, for the farming system

<正>Dear Editor,Biochar has been used as an input in the animal farming industry since 2010 (Gerlach and Schmidt, 2012; Schmidt et al., 2019). Several studies have documented the positive effects of biochar, used as a feed supplement, on both livestock and soil health. Schmidt et al.(2019) examined 112studies, in which the addition of a small amount of biochar to fodder improved the animal immune system,     

山羊高繁殖力骨形态发生蛋白受体IB候选基因的RFLP分析

Mulsant et al.(2001)、Wilson et al.(2001)和Souza et al.(2001)报道了绵羊6号染色体上骨形态发生蛋白受体IB(bone morphogenetic protein receptor IB,BMPR-IB)基因高度保守的胞内激酶信号区域存在1个A746G突变(所表达的249号氨基酸由谷氨酰胺变成了精氨酸),证明正是这个突变(Q249R)与Booroola母羊高繁殖力完全相关。据《中国羊品种志》(1989)记载,我国地方山羊品种中,济宁青山羊繁殖力最高,产羔率平均可达293.65%。目前还未见济宁青山羊高繁殖力候选基因的研究报道。本研究以高繁殖力山羊品种(济宁青山羊)、中等繁殖力山羊品种(…     

Physical Properties of the Soils of Sibay City of the Republic of Bashkortostan

Eurasian Soil Science - The results of the study of the properties of urban soils of the city of Sibay located in the mining region of the Republic of Bashkortostan are presented. A specific...     

青海省耕地资源开发利用分析及对策研究

分析论述了青海省耕地资源开发利用的现状、特点和问题。在此基础上,提出了对青海省耕地资源进行研究的框架体系和思路,同时基于GIS/RS技术设计了相关的技术路线。最后依据所做设计对青海省耕地资源开发利用做了初步分析,并进行了相关的对策研究分析。     

物联网安全及解决措施

物联网是一个集信息通信、数据交换、传感器技术与软件工程于一体的综合性产业,探讨和分析了物联网的结构体系与发展中遇到的安全问题。     

荔枝种子结构的扫描电镜观察

荔枝种子从果实中剥离出来后, 即使在室内条件下, 也极易失水干缩, 潮湿环境中又易发霉而腐烂。扫描电镜观察表明: 种皮上布满纹孔, 水分散失面积很大; 种脐部为疏松的海绵组织, 且营养丰富。据此, 生产上应对种子彻底清洗, 并保存于适当湿度的环境中, 以提高其发芽率。     

三门峡水库库岸坍塌成因分析与防治措施研究

三门峡水库自1960年9月蓄水运行以来,库岸坍塌现象频繁发生,平均每年塌岸0.5～0.7亿m3.指出了造成库岸坍塌的原因主要是地质环境的影响以及水力条件的变化;不同的地形、地貌、地质结构和岩性特征,表现了不同的塌岸强度,其中黄土塬区为极强塌岸段,黄河Ⅱ级阶地为强烈塌岸段,黄河Ⅰ级阶地为中等强烈塌岸段;分析了引起库岸坍塌的主要水力条件有大气降水、地表水和地下水,并且不同水力条件及其变化特征,对库岸坍塌影响的方式和程度也不同;最后给出了防治库岸坍塌应采用标本兼治的原则,治标是指对塌岸进行必要的加固、支挡、衬砌等;治本就是根据引起塌岸的原因以及不同地质环境条件下的塌岸特征和水力条件,因地制宜,因害设防,从根本上进行综合治理.     

食用仙人掌萎蔫气象条件分析

塑料大棚内种植的食用仙人掌在土壤墒情较好时也有萎蔫现象发生，通过试验观测和对仙人掌生理习性的分析，发现阴雨过后天气突然放晴温度急剧上升易使仙人掌发生萎蔫现象，并提出了田间管理的应对措施。     

Heterogeneity of Organic Matter of Aggregates of Protocalcic Chernozems

Eurasian Soil Science - Layers were step-by-step removed from macroaggregates (2–1 mm in diameter) of Protocalcic Chernozems via successive abrasion in a revolving rotator during 5, 10, 15,...     

Unity of mechanisms of water and wind erosion of soils

An equation for the threshold velocity of the water or wind flow at which erosion of a homogeneous model soil begins was derived on the basis of accepted and explicitly formulated suppositions and limitations and tested using experimental data. The validity of the proposed mechanisms and equations describing the lifting force of the soil-eroding water or wind flow and the interaggregate cohesion in a model homogeneous incoherent soil was confirmed. The limit for the decrease in the threshold flow velocity with decreasing size of the soil particles (aggregates) was theoretically substantiated. The first unified equation of the threshold velocity of the water or wind flow for a homogeneous model soil in dimensionless variables was derived and experimentally justified.     

大豆连作障碍的研究进展

从生物学、微生物学和植物营养生理学的角度及诸多障碍因子等方面,综合评述和分析了国内外大豆连作研究的现状,阐述了目前国内外学者提出的各种应对连作问题的策略和技术措施,提出大豆连作障碍研究仍有待解决的问题和研究方向。