An interneuronal chemoreceptor required for olfactory imprinting in C. elegans

Animals alter their behavioral patterns in an experience-dependent manner. Olfactory imprinting is a process in which the exposure of animals to olfactory cues during specific and restricted time windows leaves a permanent memory ("olfactory imprint") that shapes the animal's behavior upon encountering the olfactory cues at later times. We found that Caenorhabditis elegans displays olfactory imprinting behavior that is mediated by a single pair of interneurons. To function in olfactory imprinting, this interneuron pair must express a G protein-coupled chemoreceptor family member encoded by the sra-11 gene. Our study provides insights into the cellular and molecular basis of olfactory imprinting and reveals a function for a chemosensory receptor family member in interneurons.     

植物基因印迹及其对种子发育的影响

基因印迹最先发现于哺乳动物的胚胎发育中,近些年研究表明也存在植物种子发育中.基因印迹成为当前植物种子发育生物学的研究热点.从印迹基因、印迹机制及其对植物种子发育的影响等方面综述了植物种子发育中基因印迹的研究进展,并提出研究中存在的问题及其解决对策,旨在为今后相关研究提供参考.     

蒙古羊胸椎数的亲本印记遗传研究

蒙古羊胸椎数的遗传方式具有亲本印记特征。调控这个性状的Ｈｏｍｅｏｂｏｘ基因突变以后由于父系等位基因或母系等位基因的甲基化,使其转录活动停止,导致父系和母系基因组对子代的遗传贡献不相等,从而使子代产生具有父系或母系特征的亲本印记性状。纯繁与正反交实验证明,在蒙古羊胞椎数的遗传过程中,父系多胸椎基因对子代的影响明显大于母系多胸椎基因,分别为３２．４２％和２１．４３％,当正常型与多胸椎型羊分别进行同型交配时,由于基因组印记效应,使部分子代的Ｈｏｍｅｏｂｏｘ突变基因和野生型基因缄默,因而后代群体中出现亲本类型不同的表型,其比例分别为１１．７６％和１９．１９％。利用蒙古羊的亲本印记遗传特点可以指导种羊选育和商品肉羊的杂交优势利用。     

水杨酸分子印迹掺氮TiO_2粉末的制备及在可见光下的选择性光催化研究

【目的】改善TiO_2在可见光下对污染物的选择性降解能力。【方法】采用改进的分子印迹溶胶-凝胶技术,以尿素、水杨酸分别为氮源和模板分子,制备水杨酸分子印迹掺氮TiO_2粉末。通过X射线衍射(XRD)、透射电镜(TEM)、紫外-可见光漫反射吸收光谱(UV-Vis DRS)和低温N_2物理吸附-脱附(BET)等技术对制备样品进行表征。【结果】样品均为锐钛矿相,氮掺杂致使TiO_2光吸收带边红移,分子印迹使TiO_2具有了更为发达的孔结构和孔型,掺杂和分子印迹均有效地增大了比表面积。可见光下,与催化降解苯甲酸及甲基橙相比,分子印迹掺氮TiO_2对水杨酸的选择性降解率较高,达96.0%。【结论】水杨酸分子印迹和氮掺杂有效地改善了TiO_2的选择性和可见光活性。     

Imprinting and the epigenetic asymmetry between parental genomes

Genomic imprinting confers a developmental asymmetry on the parental genomes, through epigenetic modifications in the germ line and embryo. These heritable modifications regulate the monoallelic activity of parental alleles resulting in their functional differences during development. Specific cis-acting regulatory elements associated with imprinted genes carry modifications involving chromatin structural changes and DNA methylation. Some of these modifications are initiated in the germ line. Comparative genomic analysis at imprinted domains is emerging as a powerful tool for the identification of conserved elements amenable to more detailed functional analysis, and for providing insight into the emergence of imprinting during the evolution of mammalian species. Genomic imprinting therefore provides a model system for the analysis of the epigenetic control of genome function.     

印记基因研究进展

总结了印记基因的特点和调控机制,并综述了基因印记在动物育种中的应用。     

分子印迹技术及其应用

综述了分子印迹技术及其作用机理和分子印迹聚合物的合成,着重介绍分子印迹技术在手性分离、固相萃取、传感器和催化等领域的应用,并提出分子印迹技术尚需解决的问题和应用前景。     

Molecular biology. Mothers setting boundaries

Certain genes are only expressed at one allele, a phenomenon called imprinting. Although it is well established that one allele of certain imprinted genes is silenced through methylation, this does not appear to be the case for all imprinted genes. In a thoughtful Perspective, Thorvaldsen and Bartolomei discuss new findings showing that insertion of insulator elements (boundary regions) between the promoter of a gene and its enhancer (a sequence that boosts gene expression) may be another way in which genes are silenced during imprinting.     

新型的分子印迹固相萃取小柱分离富集饲料中的三聚氰胺

[目的]研制一种新型的分子印迹固相萃取小柱,用于分离富集饲料中的三聚氰胺。[方法]采用本体聚合法制备了三聚氰胺分子印迹聚合物,以该聚合物为填料制作三聚氰胺分子印迹固相萃取(MIP-SPE)小柱,优化了固相萃取条件,应用高效液相色谱(HPLC)法测定浓缩液中的三聚氰胺含量。[结果]自制的MIP-SPE小柱可以从饲料中选择性地分离、富集三聚氰胺,有效地去除饲料中的复杂基质,加标回收率约为95%。MIP-SPE小柱与空白印迹固相萃取小柱(NMIP-SPE)的对比试验表明,前者的萃取效率明显高于后者。[结论]自制的新型三聚氰胺MIP-SPE小柱可用于饲料提取液中的三聚氰胺高选择性分离富集,使用简便,具有广阔的应用前景。     

分子印迹技术在天然产物分离纯化中的应用

天然产物体系复杂,且有效成分含量低,采用一般的分离方法富集难度较大.分子印迹技术是制备高选择性分离介质的有效技术手段,分子印迹聚合物(MIPs)的选择性强,分离操作简单,在各种分离纯化中展现了良好的应用前景.文章综述了目前分子印迹技术在天然产物的分离纯化中的研究进展.     

外遗传分子生物学研究进展

该文综述了外遗传 (Epigenetics)这一新的分子生物学研究领域的提出、发展和最新研究进展 .指出外遗传是DNA碱基序列之外的遗传系统 .阐述了DNA甲基化、RNA介导的基因沉默、基因组印记和组蛋白密码等外遗传相关因素在生物体生长发育过程中对基因表达的重要调控作用 ,以及这些因素与生物体的防御机制和生物遗传信息的传递间存在的密切联系 ,并提出了从外遗传角度探索物种进化和生物适应逆境的新途径 .     

分子印迹聚合物制备新进展

分子印迹技术是当今科学研究的热点之一。介绍了分子印迹技术的原理以及沉淀聚合法、种子溶胀悬浮聚合法、表面模板聚合法等几种制备分子技术聚合物方法的最新研究进展。     

计算机模拟在分子印迹聚合物制备中的应用

基于分子印迹技术的痕量分离方法正成为分析测试领域的研究热点,其关键技术是获得高亲和性和高选择性的分子印迹聚合物.目前,计算机模拟技术在分子印迹物制备过程中发挥着越来越大的作用.本文就计算机模拟在分子印迹聚合物制备中的应用现状和发展前景进行分析阐述,以期为食品、环境中有害物质的分子印迹聚合物的制备以及分子印迹技术领域的研究提供参考.     

Familial imprinting determines H-2 selective mating preferences

Inbred male mice typically prefer to mate with females of a different, non-self H-2 haplotype. To determine whether this natural preference is irrevocable or results from familial imprinting, a test system was used which relied on previous observations that B6 males (H-2b) mate preferentially with congenic B6-H-2k rather than B6 females, and B6-H-2k males with B6 females. This preference was reversed in B6 males fostered by B6-H-2k parents and in B6-H-2k males fostered by B6 parents, preference in these cases favoring the same H-2 type. Thus, H-2 selective mating preference is acquired by imprinting on familial H-2 types.     

分子印迹技术及其在痕量分析的应用

分子印迹技术是近年来集高分子合成、分子设计、分子识别、仿生生物工程等众多学科优势发展起来的一门边缘学科分支.分子印迹聚合物由于具有与天然抗体同样的识别性能和与高分子同样的抗腐蚀性能的双重优点,因而广泛应用于生物工程、临床医学、环境监测、食品工业等众多领域.介绍了分子印迹技术的基本原理,对分子印迹聚合物合成研究的最新进展进行了综述,主要介绍了它在痕量分析中的应用.     

Role for piRNAs and noncoding RNA in de novo DNA methylation of the imprinted mouse Rasgrf1 locus

Genomic imprinting causes parental origin-specific monoallelic gene expression through differential DNA methylation established in the parental germ line. However, the mechanisms underlying how specific sequences are selectively methylated are not fully understood. We have found that the components of the PIWI-interacting RNA (piRNA) pathway are required for de novo methylation of the differentially methylated region (DMR) of the imprinted mouse Rasgrf1 locus, but not other paternally imprinted loci. A retrotransposon sequence within a noncoding RNA spanning the DMR was targeted by piRNAs generated from a different locus. A direct repeat in the DMR, which is required for the methylation and imprinting of Rasgrf1, served as a promoter for this RNA. We propose a model in which piRNAs and a target RNA direct the sequence-specific methylation of Rasgrf1.     

Stimulus preferences and imprinting

Pekin ducklings were tested with respect to their preference for approaching one of two simultaneously presented, rotating, silent duck decoys, painted in a variety of colors or patterns. Some of the ducklings had not been given any previous visual experience other than that gained in a 20-minute introduction to the empty apparatus; others had previously been given the opportunity to follow one particular decoy for 20 minutes. The decoys could be grouped into three categories: those in the first category were treated as equivalent, that is, so long as the duckling had followed one of these models it would approach either. The decoys of the second category were ones to which "imprinting" occurred, that is, the ducklings showed a decided preference for the model they had originally followed, whichever it was. The third category included models, one of which was always preferred, though the controls showed no such preference. The effects of the imprinting procedure vary with the stimuli presented.     

基因组印记重组与胚胎发育

介绍了基因组印记重组对动物胚胎发育的影响。     

农业环境中农药残留的快速检测法——分子印迹技术

综述了分子印迹原理、聚合物制备方法及其在农药残留快速检测中的应用。     

Stimulus generalization of imprinting

Chicks were imprinted with a bluish object, then tested with different spectral values ranging to yellow-green. A systematic decrement in following was related to the stimulus series, although there was considerable generalization to all test values, which increased during testing. These data lead us to question the "irreversibility" of imprinting.