Genomic imprinting determines methylation of parental alleles in transgenic mice

Mouse embryogenesis relies on the presence of both the maternal and the paternal genome for development to term. It has been proposed that specific modifications are imprinted onto the chromosomes during gametogenesis; these modifications are stably propagated, and their expression results in distinct and complementary contributions of the two parental genomes to the development of the embryo and the extraembryonic membranes. Genetic data further suggest that a substantial proportion of the genome could be subject to chromosomal imprinting, the molecular nature of which is unknown. We used random DNA insertions in transgenic mice to probe the genome for modified regions. The DNA methylation patterns of transgenic alleles were compared after transmission from mother or father in seven mouse strains carrying autosomal insertions of the same transgenic marker. One of these loci showed a clear difference in DNA methylation specific for its parental origin, with the paternally inherited copy being relatively undermethylated. This difference was observed in embryos on day 10 of gestation, but not in their extraembryonic membranes. Moreover, the methylation pattern was faithfully reversed upon each germline transmission to the opposite sex. Our findings provide evidence for heritable molecular differences between maternally and paternally derived alleles on mouse chromosomes.     

茉莉酸及其生理作用和分子机理

综述了茉莉酸的生理功能和作用分子模式的研究进展。     

Distinct functions of the two isoforms of dopamine D2 receptors

Signalling through dopamine D2 receptors governs physiological functions related to locomotion, hormone production and drug abuse. D2 receptors are also known targets of antipsychotic drugs that are used to treat neuropsychiatric disorders such as schizophrenia. By a mechanism of alternative splicing, the D2 receptor gene encodes two molecularly distinct isoforms, D2S and D2L, previously thought to have the same function. Here we show that these receptors have distinct functions in vivo; D2L acts mainly at postsynaptic sites and D2S serves presynaptic autoreceptor functions. The cataleptic effects of the widely used antipsychotic haloperidol are absent in D2L-deficient mice. This suggests that D2L is targeted by haloperidol, with implications for treatment of neuropsychiatric disorders. The absence of D2L reveals that D2S inhibits D1 receptor-mediated functions, uncovering a circuit of signalling interference between dopamine receptors.     

烯效唑对杂交水稻的生理作用及增产效果研究

在杂交水稻两段育秧的不同时期用不同度烯效唑喷施叶片,通过考查秧苗素质和测定生理指标及产量,表明在第一段秧田的１叶１心期和寄秧１５ｄ后两次用１００ｍｇ／Ｌ烯效唑自理可培育出多蘖壮秧,秧苗移栽本田后生理代谢增强,叶片的叶绿素含量和光合速率提高,后期灌浆速率增大,有效穗增加,杂交水稻育秧施用烯效唑增产显著。     

具有10个元素的亚纯函数的IM惟一性像集

证明了对于复平面C上任意两个满足条件Θ(∞, f & g)＞6/7的非常数的亚纯函数f与g, 必然存在10个元素的集合S∈C使得Ē(S,f)=Ē(S,g)意味着f≡g     

抗性淀粉的生理功能及在食品工业中的应用

介绍抗性淀粉的生理功能及其在食品工业中的应用.抗性淀粉是一种新的食品资源,因其原料来源广泛,加工性能良好,并有良好的保健功能,值得大力开发.     

多聚体化对蛋白酶生理功能的影响研究进展

蛋白酶是生物体维持正常生命活动不可缺少的酶类,在食物消化、凝血、胚胎发生、组织重建、肿瘤发生等诸多生理过程中发挥着重要功能。综述了半胱氨酸蛋白酶、丝氨酸蛋白酶、金属蛋白酶和天冬氨酸蛋白酶中存在的多聚体化状态,分析了多聚体化对蛋白酶的高级结构、生物活性及酸碱稳定性的调节作用,进而探讨多聚体化对蛋白酶在细胞迁移、炎症发生、血管生成、HIV复制等生理、病理过程中功能的影响,以期为蛋白酶的多聚体化研究及开发利用提供有益参考。     

帕珠沙星分子印迹聚合物结合特性

采用甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,合成了具有高选择性的L-帕珠沙星分子印迹聚合物.印迹聚合物对模板分子的结合量明显高于空白聚合物.通过Scatchard分析研究了聚合物的选择结合性能,结果表明:分子印迹聚合物在识别帕珠沙星分子的过程中存在两类结合位点;用多点结合模型进行计算得到高亲和力的结合位点的离解常数Kd,1和最大表观结合常数Qmax,1分别为23.08 μmol/L和3.65 μmol/g,低亲和力的结合位点的离解常数Kd,2和最大表观结合常数Qmax,2分别为0.43 mmol/L和27.28 μmol/g.实验表明,分子印迹聚合物对模板分子的结合量高于其他类似物,呈现出空白聚合物没有的高选择性.     

安石榴甙分子印迹聚合物微球的制备及识别性能

以安石榴甙为模板分子,丙烯酰胺为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈(AIBN)为引发剂,乙腈为溶剂,使用沉淀聚合方法,制备分子印迹聚合物,得到纳米级微球。等温吸附实验研究表明,印迹聚合物与空白聚合物相比,对目标分子具有更好的吸附性能,在研究浓度范围内,印迹聚合物对目标分子的最大吸附量为32.6μmol/g;Scatchard分析表明,印迹聚合物具有两种不同性能的结合位点,空白聚合物有一种结合位点,印迹聚合物的最大表观结合量为243μmol/g,空白聚合物的最大表观结合量为25.3μmol/g;底物选择实验表明分子印迹聚合物对安石榴甙具有更高的选择性能。     

染料木素分子印迹聚合物的合成与性能研究

目的研究染料木素分子印迹聚合物的合成及吸附性能。方法采用热聚合法,以染料木素为模板分子,丙烯酰胺为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,在甲醇和N,N-二甲基甲酰胺(φ1∶φ2=9∶1)混合溶剂中制备分子印迹聚合物,并对聚合物进行表征;通过Scatchard方程考察了聚合物的结合特性及对其他结构相似的化合物的选择性吸附能力,研究聚合物的吸附动力学特征。结果聚合物通过氢键形成两类结合位点,并且对染料木素有比较明显的吸附特性。结论染料木素分子印迹聚合物有明显的选择性。     

4-甲基二苯并噻吩印迹聚合物的制备及其吸附性能

以纳米二氧化硅为载体,4-甲基二苯并噻吩为模板,4-乙烯基吡啶为功能单体,通过表面分子印迹法制备纳米二氧化硅表面4-甲基二苯并噻吩印迹聚合物。利用红外光谱和氮气吸附对其进行表征,同时采用静态吸附实验考察该聚合物的吸附性能。研究结果表明:在载体表面合成了印迹聚合物,其吸附量远大于非印迹聚合物的吸附量,前者吸附动力学符合pseudo-first-order model,后者符合pseudo-first-order model和pseudo-second-ordermodel。印迹聚合物的吸附等温线满足Freundich等温吸附方程,属于多分子层吸附;与结构类似的二苯并噻吩和4,6-二甲基二苯并噻吩相比,印迹聚合物对模板4-甲基二苯并噻吩显示了特异的识别选择性与优良的结合亲和性;此外,印迹聚合物还能循环再生利用。     

甲基对硫磷分子印迹整体柱的制备及其在固相萃取中的应用

以甲基对硫磷为模板分子,采用原位逐步聚合法制备了具有良好识别性能的分子印迹聚合物(MIP)整体柱,系统考察了甲基对硫磷与其结构类似物在该柱上的选择性分离富集特性.用聚合物整体柱固相萃取了蜂蜜中的甲基对硫磷.结果表明,聚合物整体柱对模板分子产生了印迹效应,对甲基对硫磷有明显的选择性.本文以采用C18色谱柱,以甲醇-水(体积比为85:15)为流动相,流速为1.0mL/min,吸收波长为270nm,可在15分钟实现甲基对硫磷的测定.     

分子印迹电化学发光传感器检测毒死蜱

石墨相氮化碳纳米薄片（g-C₃N₄NSs）具有优良的电化学发光（ECL）性能和良好的成膜特性.以g-C₃N₄NSs作为ECL材料,利用其良好的成膜性能将其固定在玻碳电极（GCE）上,再以毒死蜱（CPF）作模板分子,甲基丙烯酸（MAA）作功能单体,通过分子自组装制备分子印迹聚合物（MIP）.将该聚合物引入g-C₃N₄NSs修饰电极,构建了一个MIP-ECL传感器.除去模板分子的传感器能够选择性识别CPF,利用CPF对g-C₃N₄NSs ECL信号的淬灭作用实现了CPF的高灵敏、高选择性检测.传感器对CPF的线性响应范围是1.0×10^-8~1.0×10^-4mol·L^-1,检出限（LOD）是5.0 nmol·L^-1,用于蔬菜中CPF残留量检测,结果令人满意.     

布洛芬手性拆分分子印迹复合膜的制备与表征

以接枝环糊精的醋酸纤维素复合物为铸膜材料,S-布洛芬为印迹分子,采用相转化法制备了用于手性分离的分子印迹膜;用FT-IR和SEM测试手段对膜的化学组成和结构形态进行了表征;通过渗透实验考察了该分子印迹膜对外消旋布洛芬的手性拆分性能。结果表明在β-环糊精接枝率为29.01%（质量分数）,模板分子浓度比为1∶10,铸膜液质量分数为12.5%的条件下,分子印迹膜对右旋布洛芬的分离因子可达2.09。     

玉米品种嫩单10在NaCl胁迫下生理变化分析

以玉米嫩单10为材料,分别用0,25,50,75 mmol/L的NaCl对其幼苗进行胁迫处理,并在胁迫处理后的2,4,6d测定幼苗叶及根中的脯氨酸含量,幼苗叶中还原糖含量、蛋白质含量,结果显示:在同一胁迫时间里,幼苗叶及根中脯氨酸含量随NaCl浓度的增加而上升;幼苗叶中还原糖含量随NaCl浓度的增加出现上升趋势,蛋白质含量随NaCl浓度的升高出现下降趋势。表明玉米嫩单10幼苗对NaCl胁迫具有一定的顺应反应。     

Central target for the behavioural effects of vasopressin neuropeptides

The neurohypophysial hormone vasopressin exerts antidiuretic, vasopressor and behavioural effects (for example, facilitation of memory processes). Vasopressin may alter animal behaviour via direct effect on brain processes. Recently, however, it has been suggested that vasopressin acts mainly at peripheral receptor systems and influences behavioural mechanisms by altering visceral afferent signals. We now present data showing that (1) central administration of [Arg8]vasopressin (AVP) and more potently [pGlu, Cyt]AVP(4-8), the desglycinamide derivative of a peptide generated from AVP by brain synaptic membranes, produce the behavioural effect (promotion of passive avoidance behaviour) without the pressor effect; (2) central administration of a vasopressor antagonist blocks the behavioural but not the pressor effect of systemically administered AVP; and (3) [pGlu, Cyt]AVP(4-8) induces the behavioural effect in the absence of the pressor effect. The results indicate that AVP and related peptides affect passive avoidance behaviour by a direct central action and that the structural requirement for activation of central vasopressin receptors differs from that of the peripheral cardiovascular receptors, although both can be blocked by the same vasopressor antagonist.     

具有父母照顾的捕食者捕食模型分析

分析了一个描述生态系统的反应扩散方程组.在此系统中,捕食者被分成不成熟和成熟两部分,不成熟的捕食者不能捕获猎物而是靠父母喂养;假设不成熟的捕食者的成熟率是食物的函数,研究了该系统的耗散性以及常数稳态解的局部稳定性.