Nerve growth factor gene expression in the developing rat brain

The regulation of nerve growth factor (NGF) protein and NGF messenger RNA (mRNA) in the developing rat brain has been studied to assess the hypothesis that NGF supports the differentiation of cholinergic neurons in the basal forebrain. In the adult, the major targets of these neurons, the hippocampus and neocortex, contain the highest concentrations of NGF mRNA, but comparatively low ratios of NGF protein to its mRNA. In contrast, a high concentration of NGF protein and a low concentration of NGF mRNA were seen in the basal forebrain, consistent with retrograde transport of NGF protein into this region from the neocortex and hippocampus. In these two target regions NGF and NGF mRNA were barely detectable at birth, their concentrations increased to a peak at day 21, and then NGF mRNA, but not NGF protein, declined threefold by day 35. NGF accumulation in the basal forebrain paralleled that in the target regions and preceded an increase in choline acetyltransferase, suggesting that the differentiation of cholinergic projection neurons is indeed regulated by retrogradely transported NGF. In addition, high ratios of NGF protein to NGF mRNA, comparable to that in the basal forebrain, were seen in the olfactory bulb and cerebellum, suggesting that NGF may be transported into these regions by unidentified neurons.     

Hyperactivity and brain catecholamines in lead-exposed developing rats

Newborn rats that suckled mothers eating a diet containing 4 percent lead carbonate display hyperactivity, aggressiveness, and excessive stereotyped behavior starting at 4 weeks of age. There is an eightfold increase in the concentration of lead in brain, no change in norepinephrine, but a 20 percent decrease in dopamine relative to coetaneous controls. This suggests a relationship between central nervous system dysfunction due to lead and dopamine metabolism in brain.     

Microtubular protein: synthesis and metabolism in developing brain

In the developing mouse brain 40 percent of the labeled soluble protein found found after injection of leucine-C(14) consists of subunits with a molecular weight of 60,000 and with other characteristics of microtubular protein. This protein has a half-life of about 4 days.     

Protein metabolism in the developing brain: influence of birth and gestational age

Incorporation of carbon-14-labeled phenylalanine into brain protein of newborn pigs falls sharply within 24 hours after birth. This decrease is related to the time of birth rather than the gestational age of the piglets, although the latter is also associated with a gradual decrease in brain protein synthesis.     

Regulation of chamber-specific gene expression in the developing heart by Irx4

The vertebrate heart consists of two types of chambers, the atria and the ventricles, which differ in their contractile and electrophysiological properties. Little is known of the molecular mechanisms by which these chambers are specified during embryogenesis. Here a chicken iroquois-related homeobox gene, Irx4, was identified that has a ventricle-restricted expression pattern at all stages of heart development. Irx4 protein was shown to regulate the chamber-specific expression of myosin isoforms by activating the expression of the ventricle myosin heavy chain-1 (VMHC1) and suppressing the expression of the atrial myosin heavy chain-1 (AMHC1) in the ventricles. Thus, Irx4 may play a critical role in establishing chamber-specific gene expression in the developing heart.     

Genetic properties influencing the evolvability of gene expression

Identifying the properties of gene networks that influence their evolution is a fundamental research goal. However, modes of evolution cannot be inferred solely from the distribution of natural variation, because selection interacts with demography and mutation rates to shape polymorphism and divergence. We estimated the effects of naturally occurring mutations on gene expression while minimizing the effect of natural selection. We demonstrate that sensitivity of gene expression to mutations increases with both increasing trans-mutational target size and the presence of a TATA box. Genes with greater sensitivity to mutations are also more sensitive to systematic environmental perturbations and stochastic noise. These results provide a mechanistic basis for gene expression evolvability that can serve as a foundation for realistic models of regulatory evolution.     

Gene cloning and expression analyses of WBC genes in the developing grapevine seeds

White-brown complex (WBC) transporters, also called half-size ATP binding cassette G (ABCG) transporters, are involved in many biological processes, including seed development; however, the WBC transporters in grapevines received less attention to date. To reveal the molecular characteristics of WBCs and the connection between WBCs and agronomic traits of stenospermocarpic (seedless) grapevine, we carried out a genomic census and analysis of ovule-associated expression for VvWBC genes in grapevine. We identified 30 VvWBC genes and cloned full-length complementary DNAs (cDNAs) for 20 of these. The tissue or organ-specific expression analysis showed that several VvWBCs exhibited distinct expression patterns with some showing tissue specificity. Twelve VvWBC genes were found to be expressed in the developing ovules. Moreover, the results of quantitative real-time PCR (qRT-PCR) suggested that four of twelve ovule-expressed VvWBCs have distinct expression profiles during the development of ovules between seeded and stenospermocarpic grapevines. These four genes might be involved in ovule abortion. Meanwhile, chromosome mapping, multiple sequence alignments, exon/intron structure analyses and synteny analyses were preformed on VvWBC genes. Our experiments provide a new perspective on the mechanism of stenospermocarpic seedlessness and put forward a framework for further study of WBC transporters.     

Gene expression profiles in the brain predict behavior in individual honey bees

We show that the age-related transition by adult honey bees from hive work to foraging is associated with changes in messenger RNA abundance in the brain for 39% of approximately 5500 genes tested. This result, discovered using a highly replicated experimental design involving 72 microarrays, demonstrates more extensive genomic plasticity in the adult brain than has yet been shown. Experimental manipulations that uncouple behavior and age revealed that messenger RNA changes were primarily associated with behavior. Individual brain messenger RNA profiles correctly predicted the behavior of 57 out of 60 bees, indicating a robust association between brain gene expression in the individual and naturally occurring behavioral plasticity.     

Genetic control of lactate dehydrogenase expression in mammalian tissues

The amount of lactate dehydrogenase isozyme 4 in erythrocytes of mice is controlled by alleles at the Ldr-1 locus. The A subunits of lactate dehydrogenase from erythrocytes deficient in isozyme 4 cannot assemble in vitro with B subunits to form active isozyme. The inability to form hybrid enzyme is not due to a mutation in the structural gene for the A polypeptide. Rather, a factor that is bound to the A subunits of erythrocytes restricts free exchange with B subunits.     

外源激素影响苦瓜种子发育过程中蛋白表达的初步分析

[目的]研究外源ABA和GA对苦瓜种子发育过程中蛋白质表达的影响,揭示外源ABA和GA对苦瓜种子蛋白质累积进程调控的生理机制.[方法]以密瘤小果型苦瓜MC26为材料,在花后第5d分别用ABA和GA处理果实,以清水处理为对照;运用双向电泳分析苦瓜种子发育过程中蛋白质组的动态变化.[结果]不同处理中,经ABA处理且花后22 d采收的苦瓜种子蛋白表达量和蛋白条带数均最高,经GA处理且花后28 d采收的苦瓜种子蛋白表达量和蛋白条带数均最低.经GA处理的苦瓜种子蛋白表达量低于对照,而经ABA处理的苦瓜种子中低分子量(18～35 kD)蛋白表达量略高于对照.2-DE图谱分析结果表明,经外源ABA和GA处理的苦瓜种子分别出现23和26个差异表达蛋白质点;其中ABA处理上调表达的蛋白点有13个,下调表达的蛋白点有10个;GA处理上调表达的蛋白点有15个,下调表达的蛋白点有11个.选用表达量明显变化的19个蛋白质点,通过MALDI-TOF-TOF MS分析和数据库检索,成功鉴定出9个差异表达蛋白质点,涉及到胁迫响应、糖酵解、贮藏和未知蛋白等4个功能类别.[结论]ABA和GA处理的苦瓜种子贮藏蛋白的表达与对照存在明显差异,说明外源ABA和GA对苦瓜种子贮藏蛋白累积具有一定的调控作用.     

Dynamic organization of developing Purkinje cells revealed by transgene expression

The cerebellum has many properties that make it a useful model for investigating neural development. Purkinje cells, the major output neurons of the cerebellar cortex, have drawn special attention because of the availability of biochemical markers and mutants that affect their development. The spatial expression of L7, a protein specific for Purkinje cells, and L7 beta Gal, a gene expressed in transgenic mice that was constructed from the L7 promoter and the marker beta-galactosidase, delineated bands of Purkinje cells that increased in number during early postnatal development. Expression of the transgene in adult reeler mutant mice, which show inverted cortical lamination, and in primary culture showed that the initial expression of L7 is intrinsic to Purkinje cells and does not depend on extracellular signals. This may reflect an underlying developmental map in cerebellum.     

欧美山杨杂种插穗不定根2个发育时期基因表达谱分析

以欧美杂种山杨嫩枝插穗为实验材料,进行扦插不定根生成过程中插穗形态和解剖学观察,通过Solexa高通量测序对扦插后6和12 d插穗不定根生成部位进行转录水平上的检测分析。插穗解剖观察发现扦插后6 d为根原基的诱导期,12 d为不定根的伸长生长期,对插穗不定根2个时期高通量测序获得差异表达基因2 328个。对筛选出的显著差异表达基因进行功能注释、分类和KEGG及pathway分析,确定2个山杨样本中差异表达基因参与的生化代谢和信号转导途径。      

柠檬酸对小鼠脑组织bcl-2表达的影响

为了探讨柠檬酸对机体的毒副作用,选用昆明系健康雄性小鼠40只,随机分成4组,每组10只,饲养1周后,腹腔注射一定剂量的生理盐水及低(180mg·kg-1)、中(270mg·kg-1)、高(360mg·kg-1)质量浓度的柠檬酸溶液.每周注射1次,连续注射3周,第3次注射后的第7天,所有小鼠均颈椎脱臼处死,采取小鼠的脑组织分别于液氨和-20℃各保存1份备用.通过RT-PCR法和ELISA法分别检测小鼠脑组织中bcl-2基因表达水平和蛋白表达量.结果显示,柠檬酸处理组与对照组相比,bcl-2基因表达水平均无统计学上的差异(P＞0.05);中剂量柠檬酸处理时,bcl-2蛋白的表达量达到最高值,且与对照组呈现显著差异(P＜0.05),上升了23％,柠檬酸高剂量组与中剂量组相比,bcl-2蛋白的表达量呈显著降低(P＜0.05);其它组间均无统计学上的差异(P＞0.05).说明腹腔注射270mg·kg-1的柠檬酸可显著提高小鼠脑组织bcl-2蛋白的表达量;但本试验设置的柠檬酸梯度对bcl-2基因表达水平无显著影响.     

小偃6号HMW-GS表达动态研究

以小偃 6号为试验材料 ,在其开花至成熟期 ,每隔 2～ 4d采收 1次籽粒 ,提取籽粒中的麦谷蛋白 ,通过十二烷基硫酸钠 -聚丙烯酰胺凝胶电泳 (SDS- PAGE)对高分子质量的麦谷蛋白亚基 (HMW- GS)进行分离。结果表明 :高分子质量麦谷蛋白在籽粒成熟过程中 ,各个亚基大约在花后 12 d开始表达 ,但不同亚基开始表达时期稍有差异 ;在花后 16 d之前 ,各个亚基蛋白的绝对量增长缓慢 ;花后 16 d之后 ,各个亚基蛋白绝对量迅速增加至一稳定值 ,且花后 2 0 d之后各个亚基蛋白的相对含量基本保持不变。     

脑特异性分子标志物vsnl1基因的克隆及原核表达

从健康BALB/c小鼠脑组织提取总RNA,逆转录获得cDNA.根据GenBank公布的视锥蛋白样基因1(vsnl1)基因序列设计引物,以鼠脑cDNA为PCR模板扩增vsnl1.将目的片段克隆至pMD18-T载体,经酶切和测序鉴定重组质粒pMDT-v.将vsnl1基因亚克隆至6×His原核表达载体pROEX-HTb,转化大肠杆菌DH5α,用IPTG诱导表达和Ni-NTA柱纯化,并采样进行SDS-PAGE分析.结果表明:RT-PCR扩增产生了与vsnl1大小吻合的目的片段,测序及BLAST比对提示与已公布序列的同源性为99%,将序列提交GenBank.SDS-PAGE显示,经IPTG诱导,重组质粒pROEX-v转化菌表达了约22ku的蛋白,与预期分子量大小一致.     

发达国家与发展中国家的转基因认知比较研究

转基因技术是解决新世纪农业与环境等诸多问题的新技术,但也引起了公众对转基因生物安全的关心和担心。本研究引述比较了美国欧盟等发达国家公众对转基因生物安全的认知状况,发现美国公众对生物技术与转基因的了解程度不一,公众对转基因食品消费与安全的认知也有差异。对比转基因产品在发达国家美国、英国、日本以及发展中国家哥伦比亚和我国公众的认知与影响,表明发达国家的公众愿意购买转基因食品的意愿低于那些缺乏高质量食品消费的发展中国家公众的比例。本研究分析总结了对政府的信任度、对科学的态度和媒体宣传,以及不同经济发展水平给公众判定转基因产品利益与风险认知的影响和可能的相关因素。     

酸枣仁散对运输应激大鼠脑内5-HT表达的影响

为研究运输应激对脑内五羟色胺(5-hydroxytryptamine,5-HT)表达的影响及酸枣仁散对运输应激的调控作用,试验采用摇床模拟公路运输途中的摇晃、高温和拥挤等因素,建立大鼠运输应激模型(35℃,60r/min,每天应激2h,连续7d)。将40只大鼠随机分为对照组、酸枣仁组、应激组和应激+酸枣仁组,分别处理7d后,断头取脑,利用酶联免疫吸附法(ELISA)和免疫组化法检测各组大鼠脑区5-HT含量变化及分布。酶联免疫吸附法检测结果显示,与对照组相比,应激组大鼠中缝核、海马和纹状体等脑区5-HT表达量均明显减少(P0.05),应激+酸枣仁组较应激组5-HT表达量显著增加(P0.05)。免疫组化结果显示,在中缝背核及其亚核DRDsh、DRv和DRc亚核,应激组大鼠5-HT灰度值与对照组相比显著下降(P0.05),应激+酸枣仁组与应激组相比显著上升(P0.05)。以上结果表明,运输应激可以导致中枢神经系统部分脑区5-HT含量下降,而酸枣仁散可能通过上调脑内5-HT的含量来调控运输应激。     

Cloning and expression of a rat brain GABA transporter

A complementary DNA clone (designated GAT-1) encoding a transporter for the neurotransmitter gamma-aminobutyric acid (GABA) has been isolated from rat brain, and its functional properties have been examined in Xenopus oocytes. Oocytes injected with GAT-1 synthetic messenger RNA accumulated [3H]GABA to levels above control values. The transporter encoded by GAT-1 has a high affinity for GABA, is sodium-and chloride-dependent, and is pharmacologically similar to neuronal GABA transporters. The GAT-1 protein shares antigenic determinants with a native rat brain GABA transporter. The nucleotide sequence of GAT-1 predicts a protein of 599 amino acids with a molecular weight of 67 kilodaltons. Hydropathy analysis of the deduced protein suggests multiple transmembrane regions, a feature shared by several cloned transporters; however, database searches indicate that GAT-1 is not homologous to any previously identified proteins. Therefore, GAT-1 appears to be a member of a previously uncharacterized family of transport molecules.