对TMV不同抗性番茄品种的叶绿体DNA限制性内切酶酶谱分析

选用对TMV有抗性和敏感的番茄品种、制备其ct-DNA, 用限制性内切酶BumHI、EcoRI和PstI完全酶解, 三种酶切图谱与前人报道一致, 由酶切片段计算番茄ct-DNA。分子量约为156.9kb。比较抗性和敏感品种的ct-DNA图谱, 发现三种酶切图谱均存在差异, 但由差异片段计算分子量之和又很除近。我们推测这是由于检基顺序变异或小段DNA顺序插入或缺失所造成, 由此证明, 叶绿体基因组与核中的TMV抗性基因, 共同决定着植物体对TMV的抗性。     

氯化钇和氯化镨引起的人淋巴细胞DNA分子损伤的研究

用单细胞凝胶电泳法检测了稀土化合物氯化钇和氯化镨对人外周血淋巴细胞的ＤＮＡ损伤效应。结果表明,与对照相比,３种不同浓度的氯化钇和氯化镨均可引起淋巴细胞ＤＮＡ受损后ＤＮＡ迁移率的显著升高,受损伤细胞的百分率与对照差异明显,提示氯化钇和氯化镨具有一定的遗传毒性。     

2型糖尿病患者醛糖还原酶基因5′调控区的多态性与功能

 为了探讨醛糖还原酶基因 5′调控区存在的可引起蛋白质表达发生改变的遗传变异及这些变异与糖尿病视网膜病变的相关性 ,应用PCR SSCP分析对醛糖还原酶基因 5′调控区 - 60 9～ + 4 0的DNA片段进行了筛选 .所有变异体均进行DNA序列分析并克隆至氯霉素乙酰转移酶报告基因载体(pCATreportervector) ,然后将重组质粒转染HeLa细胞 ,通过检测氯霉素乙酰转移酶的活性求出启动子的相对活性 .同时进行凝胶滞留试验与足纹分析以确定DNA与核蛋白的相互作用 .结果显示 ,在 1 45名 2型糖尿病患者及 1 2 3名正常对照的醛糖还原酶基因 5′调控区除野生型外 ,共发现 2种多态性 [C( - 1 0 6)T、C( - 1 2 )G].在正常对照与患者中 ,基因型WT WT ,WT C( - 1 2 )G和WT C( - 1 0 6)T的发生率无显著性差异 .在有视网膜并发症与无视网膜并发症的 2型糖尿病患者中 ,WT C( -1 0 6)T的发生率分别为 35 5%和 1 7 9% ( χ2 =4 0 0 ,P <0 0 5) ,WT C( - 1 2 )G的发生率分别为1 5 5%和 3 3% ( χ2 =3 43,P >0 0 5) .在有并发症的患者中 ,WT C( - 1 2 )G和WT C( - 1 0 6)T两者的总发生率为 42 3% ,显著高于无并发症的患者 ( 2 0 0 % ) ( χ2 =6 2 3,P <0 0 2 5) .野生型 ,C( - 1 2 )G和C( - 1 0 6)T等 3种调控序列的相对活性分别为     

Conditioned medium from hypoxia-treated adipocytes renders muscle cells insulin resistant

Adipose tissue hypoxia is an early phenotype in obesity, associated with macrophage infiltration and local inflammation. Here we test the hypothesis that adipocytes in culture respond to a hypoxic environment with the release of pro-inflammatory factors that stimulate macrophage migration and cause muscle insulin resistance. 3T3-L1 adipocytes cultured in a 1% O2 atmosphere responded with a classic hypoxia response by elevating protein expression of HIF-1α. This was associated with elevated mRNA expression and peptide release of cytokines TNFα, IL-6 and the chemokine monocyte chemoattractant protein-1 (MCP-1). The mRNA and protein expression of the anti-inflammatory adipokine adiponectin was reduced. Conditioned medium from hypoxia-treated adipocytes (CM-H), inhibited insulin-stimulated and raised basal cell surface levels of GLUT4myc stably expressed in C2C12 myotubes. Insulin stimulation of Akt and AS160 phosphorylation, key regulators of GLUT4myc exocytosis, was markedly impaired. CM-H also caused activation of JNK and S6K, and elevated serine phosphorylation of IRS1 in the C2C12 myotubes. These effects were implicated in reducing propagation of insulin signaling to Akt and AS160. Heat inactivation of CM-H reversed its dual effects on GLUT4myc traffic in muscle cells. Interestingly, antibody-mediated neutralization of IL-6 in CM-H lowered its effect on both the basal and insulin-stimulated cell surface GLUT4myc compared to unmodified CM-H. IL-6 may have regulated GLUT4myc traffic through its action on AMPK. Additionally, antibody-mediated neutralization of MCP-1 partly reversed the inhibition of insulin-stimulated GLUT4myc exocytosis caused by unmodified CM-H. In Transwell co-culture, hypoxia-challenged adipocytes attracted RAW 264.7 macrophages, consistent with elevated release of MCP-1 from adipocytes during hypoxia. Neutralization of MCP-1 in adipocyte CM-H prevented macrophage migration towards it and partly reversed the effect of CM-H on insulin response in muscle cells. We conclude that adipose tissue hypoxia may be an important trigger of its inflammatory response observed in obesity, and the elevated chemokine MCP-1 may contribute to increased macrophage migration towards adipose tissue and subsequent decreased insulin responsiveness of glucose uptake in muscle.     

Kisspeptins在孕早期血浆和胎盘组织中的表达及其意义

目的:研究kisspeptins在孕早期血浆和胎盘组织中的表达,拟探讨其来源及其在妊娠中意义.方法:采用酶联免疫吸附法(ELISA),检测40例孕早期妇女和35例正常未妊娠妇女血浆kisspeptins的表达水平,且分析其与hCG的相关性;采用免疫组织化学方法进行其组织学定位.结果:(1)kisspeptins在妊娠组...     

蛋白质内含子介导的蛋白纯化系统在变性条件下的应用

由蛋白质内含子介导的亲和蛋白质纯化系统(IMPACT)已得到广泛应用,通过其纯化得到的目的蛋白不含蛋白纯化标签以及多余的氨基酸残基,且操作简单成本低廉。这些优点使得其相对于其他蛋白纯化系统有着无与伦比的优势。但是现有报道都局限于非变性条件下使用,这往往会限制其在一些包涵体蛋白变性条件下使用。以一已知表达形成包涵体形式的丝素蛋白为例,研究IMPACT系统在时变性条件下使用变性剂浓度、温度和诱导断裂还原剂浓度。实验表明,在4 M尿素,100 mM DTT室温作用下蛋白质内含子会获得最大断裂效率(80%)。柱上在线断裂实验表明,其最终蛋白得率超过65%。     

Climatic and technological ceilings for Chinese rice stagnation based on yield gaps and yield trend pattern analysis

Climatic or technological ceilings could cause yield stagnation. Thus, identifying the principal reasons for yield stagnation within the context of the local climate and socio‐economic conditions are essential for informing regional agricultural policies. In this study, we identified the climatic and technological ceilings for seven rice‐production regions in China based on yield gaps and on a yield trend pattern analysis for the period 1980–2010. The results indicate that 54.9% of the counties sampled experienced yield stagnation since the 1980. The potential yield ceilings in northern and eastern China decreased to a greater extent than in other regions due to the accompanying climate effects of increases in temperature and decreases in radiation. This may be associated with yield stagnation and halt occurring in approximately 49.8–57.0% of the sampled counties in these areas. South‐western China exhibited a promising scope for yield improvement, showing the greatest yield gap (30.6%), whereas the yields were stagnant in 58.4% of the sampled counties. This finding suggests that efforts to overcome the technological ceiling must be given priority so that the available exploitable yield gap can be achieved. North‐eastern China, however, represents a noteworthy exception. In the north‐central area of this region, climate change has increased the yield potential ceiling, and this increase has been accompanied by the most rapid increase in actual yield: 1.02 ton ha^?1 per decade. Therefore, north‐eastern China shows a great potential for rice production, which is favoured by the current climate conditions and available technology level. Additional environmentally friendly economic incentives might be considered in this region.     

植物肌醇半乳糖苷合酶的生理功能和调控机制

植物肌醇半乳糖苷合酶（galactinol synthase, GolS）是高等植物棉子糖类寡糖合成途径中的关键酶,为棉子糖系列寡糖提供活化的半乳糖基,调控植物体内棉子糖（raffinose, RFO）系列寡糖的生物合成与积累。编码该酶的基因属于糖基转移酶（glycosyltransferases, GTs）GT8基因家族的亚家族。GolS参与合成的最终产物棉子糖家族低聚糖（raffinose family oligosaccharides,RFOs）是植物中重要的碳水化合物存在形式,在细胞内可溶性强,可作为脱水保护剂;还能发挥稳定膜结构的作用。同时,GolS催化合成的直接产物肌醇半乳糖苷（galactinol）和RFOs都能作为羟基自由基捕获分子参与活性氧的清除。因此,GolS参与的代谢途径在植物碳同化物的贮存与运输、生物和非生物逆境响应、种子的脱水效应等生命过程中均发挥了重要作用。GolS基因结构差异与表达模式不同,导致不同GolS基因参与的生物学功能具有很大的差异。研究植物中不同GolS基因的结构特征,组织特异性表达特性及它们响应不同生长发育阶段、环境变化的表达特性,对了解GolS参与的生物学功能具有重要意义。同时,在分子生物学水平上,深入了解调控植物GolS基因的分子调控机制,为通过遗传工程或分子辅助育种等手段,利用GolS改良农林作物的经济性状提供理论支持。本文针对近年来植物中GolS基因的生理功能和调控机制的研究进行了综述。     

Nanoparticle self-assembly by a highly stable recombinant spider wrapping silk protein subunit

Artificial spider silk proteins may form fibers with exceptional strength and elasticity. Wrapping silk, or aciniform silk, is the toughest of the spider silks, and has a very different protein composition than other spider silks. Here, we present the characterization of an aciniform protein (AcSp1) subunit named W₁, consisting of one AcSp1 199 residue repeat unit from Argiope trifasciata. The structural integrity of recombinant W₁ is demonstrated in a variety of buffer conditions and time points. Furthermore, we show that W₁ has a high thermal stability with reversible denaturation at ∼71 °C and forms self-assembled nanoparticle in near-physiological conditions. W₁ therefore represents a highly stable and structurally robust module for protein-based nanoparticle formation.