Dopamine D2 receptor-mediated Akt/PKB signalling: initiation by the D2S receptor and role in quinpirole-induced behavioural activation

The short and long isoforms of the dopamine D2 receptor (D2S and D2L respectively) are highly expressed in the striatum. Functional D2 receptors activate an intracellular signalling pathway that includes a cAMP-independent route involving Akt/GSK3 (glycogen synthase kinase 3). To investigate the Akt/GSK3 response to the seldom-studied D2S receptor, we established a rat D2S receptor-expressing cell line [HEK (human embryonic kidney)-293/rD2S]. We found that in HEK-293/rD2S cells, the D2/D3 agonists bromocriptine and quinpirole significantly induced Akt and GSK3 phosphorylation, as well as ERK1/2 (extracellular-signal-regulated kinase 1/2) activation. The D2S receptor-induced Akt signals were profoundly inhibited by the internalization blockers monodansyl cadaverine and concanavalin A. Activation of the D2S receptor in HEK-293/rD2S cells appeared to trigger Akt/phospho-Akt translocation to the cell membrane. In addition to our cell culture experiments, we studied D2 receptor-dependent Akt in vivo by systemic administration of the D2/D3 agonist quinpirole. The results show that quinpirole evoked Akt-Ser⁴⁷³ phosphorylation in the ventral striatum. Furthermore, intra-accumbens administration of wortmannin, a PI3K (phosphoinositide 3-kinase) inhibitor, significantly suppressed the quinpirole-evoked behavioural activation. Overall, we demonstrate that activation of the dopamine D2S receptor stimulates Akt/GSK3 signalling. In addition, in vivo Akt activity in the ventral striatum appears to play an important role in systemic D2/D3 agonist-induced behavioural activation.     

人白细胞介素18的基因克隆与表达

人白细胞介素１８（ＩＬ－１８）是新近发现的细胞因子之一．研究表明它参与Ｔ１辅助细胞介导的细胞免疫．利用ＲＴ－ＰＣＲ技术从人外周血细胞扩增得到了ＩＬ－１８的ｃＤＮＡ并测定其核酸序列．利用基因重组技术构建ＩＬ－１８的表达载体,并在大肠杆菌中进行了表达．这为以后进一步研究ＩＬ－１８的功能奠定了基础．     

Transgenic fish.

A range of transgenic animal species have been generated using DNA microinjection, and application of this technique to fish is now showing some degree of success. Studies to optimize microinjection techniques specifically for use with fish, and to investigate possible alternative methods for mass culture, should lead to the commercial production of transgenic fish able to transmit desirable characteristics, such as enhanced growth or disease resistance, to their progeny.     

雄性棉铃虫和烟青虫对雌性信息素的触角电生理反应

利用触角电位图(Electroantennogram,EAG)技术,比较研究了二近缘种棉铃虫、烟青虫对其性信息素主要成分Z—11—16：Ald、Z—9—16：Ald的触角电生理反应。剂量反应曲线表明,对Z—11—16：Ald,棉铃虫和烟青虫均有明显的EAG反应,且随浓度的增加而增强,但棉铃虫比烟青虫的反应较强;对Z—9—16：Ald,烟青虫有很强的EAG反应,棉铃虫的反应则很弱;对Z—11—16：Ald和Z—9—16：Ald以97：3和7：93比例形成的混合物,棉铃虫、烟青虫均有EAG反应,但二者之间没有显著差异[动物学报49(6)：795～799,2003]。     

猕猴桃模板DNA的提取及RAPD-PCR最佳反应体系的建立

以改良CTAB法从猕猴桃叶片中制备模板DNA ,优化了PCR热循环参数 ,建立了RAPD PCR扩增的最佳反应体系。实验结果表明 ,CTAB提取液中EDTA组分的浓度对模板提取影响很大 ,其最适浓度为 80mmol/L ;用异丙醇沉淀后不经乙醇洗涤纯化的DNA不会影响扩增效果。PCR热循环参数为 :94℃预变性 5min ;94℃变性 1min ,37℃退火 1min ,72℃延伸 2min ,循环 4 0次 ;最后在 72℃延伸 6min。     

Inhibition of Monoamine Oxidase by 7-Chloro-4-Nitrobenzofurazan

7-Chloro-4-nitrobenzofurazan (NBD-Cl) is a potent inhibitor of both types of monoamine oxidase (MAO). NBD-Cl competitively inhibited the oxidative deamination of kynuramine catalyzed by human placenta MAO-A, the oxidative deamination of benzylamine catalyzed by bovine liver MAO-B, the oxidative deamination of serotonin catalyzed by rat brain MAO-A, and the oxidative deamination of phenylethylamine catalyzed by rat brain MAO-B. In addition, a time-dependent inactivation of MAOs by NBD-Cl has been demonstrated upon incubation of the enzyme preparations with NBD-Cl at pH 9, but not at pH 7.5. The time-dependent inhibition of MAO by NBD-Cl could be prevented by the addition of 4-nitrophenyl azide, an active site-directed label of MAO, during incubation of the enzyme with NBD-Cl. On the basis of these findings, it is suggested that at pH 9, NBD-Cl modifies one (or more) essential lysine residue(s) in the active sites of the two types of MAO.     

一种新杨树菇(Agrocybe aegerita)凝集素的纯化及生化特性

用硫酸铵分级沉淀、离子交换和分子筛等方法 ,从食用菌杨树菇子实体中分离纯化了一种凝集素 ,称作为AAVP(Agrocybeaegeritaantiviralprotein) .经SDS PAGE测定其亚基的相对分子质量为15 8kD ,凝胶过滤分析分子量为 32kD .IEF PAGE计算其等电点为 3 8.AAVP不含糖 ,是一种N端焦谷氨酰环化封闭的蛋白质 ,经N端去封闭后测得N端氨基酸序列为QGVNIYNIVAGA ,用胰蛋白酶消化后得到一大片段 ,测定的氨基酸序列为PDGPWLVEK .AAVP可以凝集供试的 12种动物血和3种血型人血的血红细胞 ,但对各种血红细胞凝集滴度不同 .糖抑制实验表明 ,在供试的 18种单糖和 3种糖蛋白中 ,只有猪胃粘蛋白强烈抑制AAVP的凝血活性 .AAVP具有较好的热稳定性 ,能够忍受极端的酸碱条件 .AAVP的凝血活性不受Ca2 + 、Mg2 + 、Zn2 + 等二价阳离子的影响 .抗肿瘤活性检测表明 ,AAVP对胃癌细胞株SGC 790 1,MGC 80 3,BGC82 3及人急性白血病细胞株HL 6 0有明显的抑制作用 .AAVP对小鼠腹腔注射的半致死剂量为 15 85mg kg .     

小地老虎雄蛾中胚层生殖腺缢缩瓣膜结构和功能

该文通过光镜、电镜和生化分析等方法,详细观察了小地老虎雄蛾中胚层生殖腺缢缩的形态、数目、位置和细胞特化的瓣膜结构,并研究了缢缩的瓣膜结构和隔离中胚层生殖腺分泌物的功能。结果表明：缢缩是雄蛾中胚层生殖腺上显著收缩段,有7个,分别在雄性附腺—贮精囊、贮精囊—精包腺1段、精包腺1～5各段之间,精包腺5段—C形管;缢缩自内向外为4层,即瓣膜细胞、底膜、肌肉和围膜,肌肉层发达;缢缩瓣膜结构是细胞极度伸长特化形成的,其特点是：多数细胞伸长超过原长度的一倍以上,顶区膨大呈蘑菇突,纵横交错堵塞管腔,其顶段的微绒毛致密而细长,稠密的粗面内质网和稀疏的高尔基体环绕在核的四周,细胞间隙发达;缢缩瓣膜结构具有隔离相邻区段中胚层生殖腺分泌物的功能,致使各区段分泌物在蛋白质电泳谱带数和迁移率,以及经PAS染色后在腺腔横切面上的构象存在显著差异。     

熊蜂携带花粉的电镜鉴定及与采访植物协同演化关系的研究

通过对蜜蜂总科（Apoidea）熊蜂属Bombus15个亚属、20种的熊蜂蜂王花粉篮中携带的花粉进行电镜扫描鉴定,结果结合熊蜂及植物比较形态学、熊蜂亚属及采访植物间进化关系进行了分析。结果表明：熊蜂的采访植物包括被子植物的9目、10科,涉及原始、进化及中间3种植物类型,且颚眼距较长的熊蜂亚属既采访长管花也采访短管花植物,颚眼距较短的熊蜂亚属则只倾向于采访短管花植物。