分化抑制因子3的表达调控机理及其功能

分化抑制因子3(inhibitor of differentiation 3,Id3)属于螺旋-环-螺旋(helix-loop-helix,HLH)转录因子家族成员之一,该分子参与细胞周期调控过程,在细胞生长与发育.机体的生理及病理过程中发挥重要调控作用.其表达和功能涉及许多复杂的调控机制.     

酪氨酸对人离体滋养层细胞孕酮与hCG分泌的影响

本文观察三种剂量(2×10~(-5)mol/L,2×10~(-4)mol/L和2×10~(-3)mol/L)的酪氮酸对离体培养的滋养层细胞孕酮及hCG分泌的影响,并对其抑制效应的机理作了初步探讨。实验结果表明,三种剂量的酪氨酸均可抑制滋养层细胞孕酮分泌(P<0.01),但是,在孕酮分泌受酪氨酸抑制的同时,未见对hCG分泌发生影响(P>0.05),进一步观察了酪氨酸对滋养层细胞3β-羟甾脱氢酶活性的影响,结果表明,酪氨酸能显著抑制3β-羟甾脱氢酶活性,提示酪氨酸对滋养层细胞孕酮生成的抑制作用与抑制3β-羟甾脱氢酶活性有关。     

M-胆碱药物对大鼠皮层、腮腺和豚鼠小肠纵肌中 M-乙酰胆碱受体的作用比较

本文应用[~3H]-QNB 为放射性配基,研究 M-胆碱激动剂或阻滞剂对大鼠脑皮层、腮腺和豚鼠小肠纵肌中 M-乙酰胆碱受体竞争结合的影响。经量-效比式计算后,证明它们的作用斜率(b)约为1,表明它们作用在相同的 M-乙酰胆碱受体。阻滞剂对皮层中 M-胆碱受体的抑制结合强度次序为:QNB>阿托品,东莨菪碱>苯海索>M-8218>B-7601>M-8225>7911;而它们对腮腺中 M-乙酰胆碱受体的抑制作用次序有明显不同,即 M-8218>QNB>7911>M-8225>B-7601>苯海索>阿托品>东莨菪碱,其中阿托品和东莨菪碱的抑制结合强度分别为皮层的1/111和1/315。这提示不同靶细胞中的 M-乙酰胆碱受体与相同配基结合时有不同的专一性。试验证明包公藤甲素抑制[~3H]-QNB 的结合作用与毛果芸香碱相似,它们均为激动剂,对受体的亲和力比阻滞剂弱1000倍左右。     

邻苯二甲酸二(2-乙基己基)酯对大鼠胎盘组织的影响

目的:探讨孕期不同剂量邻苯二甲酸二(2-乙基己基)酯(DEHP)暴露对大鼠胎盘组织形态学和超微结构的影响,以推断DEHP对胎盘结构和功能的损害。方法:健康雌性Wistar大鼠40只,随机分为4组,妊娠第11日起每日给予DEHP灌胃,剂量分别为:对照组(玉米油)、低剂量组(100 mg/kg)、中剂量组(500 mg/kg)和高剂量组(1000 mg/kg),妊娠第19日处死孕鼠,取胎盘组织分别做HE染色和电镜制片,观察各剂量组胎盘形态学及超微结构的变化。结果:各剂量组胎盘形态学和超微结构的变化与DEHP摄入量呈负相关,低剂量组胎盘无明显改变;中剂量组胎盘缩小,空泡化细胞增多,微观结构显示胞质内线粒体水肿;高剂量组胎盘迷路带血窦扩张淤血严重,滋养细胞变性、坏死。结论:DEHP可导致大鼠胎盘形态结构发生改变,这种病理改变是胎盘功能减退的形态学基础,可直接影响胚胎发育和妊娠结局。     

佛波醇酯诱导HL-60细胞巨噬细胞样分化时蛋白激酶C活力及分布的改变

本文对佛波醇酶诱导人早幼粒白血病细胞系HL-60细胞分化为巨噬细胞样细胞对蛋白激酶c活力及其在亚细胞分布的变化进行了研究。蛋白激酶c活力在TPA处理1小时即明显降低,此低水平的酶活力持续整个实验时期。酶的亚细胞分布研究提示TPA处理细胞胞质组分酶活力剧烈降低,而颗粒组分存在一高盐浓度洗脱的酶活力峰。蛋白激酶c抑制剂三氟过(口了)嗪单独处理HL-60细胞导致胞质和颗粒组分酶活力升高,但并不诱导细胞分化;若与TPA合并处理细胞,酶活力又降低,此时细胞又分化为巨噬细胞样细胞。对上述结果的可能机理进行了讨论。     

脑和脊髓中的去甲肾上腺素在大鼠电针镇痛中起不同的作用

中枢神经系统中的去甲肾上腺素(NE)对针刺镇痛究竟起增强或对抗作用,目前的看法还不一致。本工作观察了电针镇痛时大鼠脑和脊髓 NE 及其主要代谢产物3-甲氧基4-羟基苯乙二醇硫酸盐(MHPG·SO_4的含量变化。结果表明:电针刺激使脑和脊髓 NE 含量下降而MHPG·SO_4含量显著升高,提示脑和脊髓 NE 的更新加速。给大鼠脑室或脊髓蛛网膜下腔注射 NE 的直接前体二羟基苯丝氨酸(DOPS)来加强 NE 的功能,或注射α、β受体阻断剂来削弱 NE 的功能,从而观察其对电针镇痛作用的影响,结果表明脑和脊髓中的 NE 在电针镇痛中起着截然不同的作用;脑内 NE 主要通过α受体对抗电针镇痛,此外兼有较弱的通过β受体加强电针镇痛的作用,而脊髓内 NE 则是通过α受体来加强电针镇痛的作用。     

植物萜类合成酶3-羟基-3-甲基戊二酰辅酶A还原酶的生物信息学分析

采用生物信息学的方法和工具对已在GenBank上注册的橡胶、烟草、辣椒、穿心莲等植物的萜类合成酶3-羟基-3-甲基戊二酰辅酶A还原酶的核酸及氨基酸序列进行分析,并对其组成成分、信号肽、跨膜拓朴结构域、疏水性/亲水性、蛋白质二级及三级结构、分子系统进化关系等进行预测和推断。结果表明该类酶基因的全长包括5′、3′非翻译区和一个开放阅读框,无信号肽,是一个跨膜的亲水性蛋白,包括两个功能HMG-CoA结合motif及两个功能NADPH结合motif,α-螺旋和不规则盘绕是蛋白质二级结构最大量的结构元件,β-转角和延伸链散布于整个蛋白质中,蛋白质的功能域在空间布局上折叠成“V”形,“V”形的两臂由螺旋状的N结构域和S结构域构成,中间部分由L结构域构成。     

高等植物的3-羟基-3-甲基戊二酰辅酶A还原酶

介绍了植物3-羟基-3-甲基戊二酰辅酶A还原酶(HMGR)的结构和调控,并简略讨论了HMGR调控与植物类异戊二烯途径的关系.     

铜绿假单胞菌一氧化氮还原酶编码基因norD的生物学功能研究

一氧化氮还原酶(Nitric oxide reductase,NOR)是反硝化过程中一个非常重要的催化酶,本文通过同源重组的方法敲除铜绿假单胞菌中norD基因,并研究该基因敲除后菌株ΔnorD在好氧条件下的表型变化。研究结果表明,与野生菌株和回补菌株相比,ΔnorD对BIT的抗性增强。同时在BIT作用下,ΔnorD泳动能力减弱、绿脓菌素的合成能力降低,但norD基因不是BIT唯一的作用位点。上述结果明确了好氧条件下norD基因的部分功能,为更好的利用反硝化过程奠定基础。     

不动杆菌Acinetobacter sp. TAC-1利用聚(3-羟基丁酸酯-co-3-羟基戊酸酯)的碳代谢机理

为阐明异养硝化-好氧反硝化(heterotrophic nitrification-aerobic denitrification, HN-AD)菌株不动杆菌(Acinetobactersp.)TAC-1利用聚(3-羟基丁酸酯-co-3-羟基戊酸酯)[poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV]的碳代谢途径,以乙酸钠(sodium acetate, SOA)为对照,考察TAC-1菌株基因水平上存在的碳水化合物代谢通路。全基因组测序结果表明,TAC-1菌株中存在gltA、icd、sucAB、acs和pckA等碳水化合物代谢酶编码基因;KEGG通路数据库注释进一步证实TAC-1菌株存在糖酵解途径(glycolyticpathway,EMP)、磷酸戊糖途径(pentosephosphate pathway, PPP)、乙醛酸循环(glyoxylate cycle, GAC)和三羧酸循环(tricarboxylic acid cycle, TCA cycle)等碳水化合物代谢通路;不同碳源的代谢物差异表达,进一步证实TAC-1菌利用PH...     

鞘内注射M受体和GDNF反义寡脱氧核苷酸抑制吗啡戒断大鼠蓝斑c-Fos表达

应用免疫组化方法观察鞘内注射毒蕈碱型乙酰胆碱(muscarinic acetylcholine receptor,M) 受体和胶质细胞源性神经营养因子(glial cell derived neurotrophic factor,GDNF)反义寡脱氧核苷酸对吗啡戒断大鼠蓝斑(locus coeruleus,LC)区内Fos表达的影响。结果显示,鞘内注射M_2受体和GDNF反义寡脱氧核苷酸明显减少大鼠吗啡戒断症状评分值(n=6,P<0.05)。正常大鼠LC区神经元Fos基础表达较低,吗啡依赖大鼠LC区神经元Fos表达增加,吗啡依赖大鼠纳酪酮(4mg/Kg,ip)催促戒断后,Fos表达进一步增加;鞘内注射M_2受体和GDNF反义寡脱氧核苷酸处理后均减少吗啡戒断大鼠LC区神经元Fos表达(n=5,P<0.05)。而鞘内注射M_1受体反义寡脱氧核苷酸处理组LC 区神经元Fos表达较吗啡戒断组没有显著差异(n=5,P>O.05)。结果提示:脊髓M_2受体调节吗啡戒断时LC区的神经元激活,而这种神经上行性激活涉及神经元与胶质细胞之间的适应性调节。     

MUSCARINIC ACETYLCHOLINE RECEPTOR SUBTYPE mRNAs IN THE HUMAN AND RAT VESTIBULAR PERIPHERY

The expression of the five muscarinic acetylcholine receptor (mAChR) subtypes (m1–m5) in the vestibular end-organs and in the primary afferent vestibular ganglia of the human and rat was studied using RT-PCR from the two tissue populations from both species. In the human, although all five mAChR subtypes were expressed in brain, only the m1, m2, and m5 mAChR subtypes were amplified from both the vestibular ganglia and the vestibular end-organs, while in the rat, all five mAChR subtypes were expressed. These data suggest that the efferent cholinergic axo-dendritic and axo-somatic synapses have a muscarinic component and that there are pharmacologic implications for patients with vestibular dysfunction.     

大鼠脑内小胶质细胞神经营养素受体的表达

神经营养素在神经元的生长、发育中的重要作用已有许多报道,但对神经胶质细胞的作用及其作用机制却知之甚少。在本研究中,我们着重对体外培养的小胶质细胞所表达的神经营养素受体进行了分析。首先,利用酚-氯仿法提取了总的细胞RNA,然后通过特异引物采用反转录多聚酶链式反应(RT-PCR)扩增得到cDNA,再用琼脂糖凝胶电泳、DNA印迹法和免疫细胞化学染色法对神经营养素受体(Trks)进行了测定。实验结果表明:体外培养的大鼠脑小胶质细胞表达高亲和力神经营养素受体TrkA、TrkB和TrkC,以及低亲和力NGF受体LNGFRp75。因此推断,神经营养素对小胶质细胞的生理及调节作用可能是通过它们相应的受体(Trks和LNGFRp75)介导的。这些结果为进一步研究神经营养素在神经系统中的作用机制及小胶质细胞的生理功能提供了资料。     

大鼠脑皮层中多巴胺受体的检定

本研究使用放射配基结合分析法,建立了对大鼠脑皮层多巴胺Ｄ＿１和Ｄ＿２型受体的检测方法。测得正常大鼠脑皮层中Ｄ＿１受体的Ｂ＿ｍａｘ,为１０３±５３ｐｍｏｌ／ｇ蛋白,Ｋ＿ｄ值为３．２±１．２ｎｍｏｌ／Ｌ;Ｄ＿２受体的Ｂ＿ｍａｘ,为２２７±７９ｐｍｏｌ／ｇ蛋白,Ｋ＿ｄ值为２．６±ｌ．３ｎｍｏｌ／Ｌ。     

Properties of putative nicotinic and muscarinic cholinergic receptors in the central nervous system of Locusta migratoria

Nervous tissue preparations from Locusta migratoria specifically bind potent nicotinic (α-bungarotoxin) and muscarinic (quinuclidinyl benzilate) ligands. Binding properties and pharmacological data indicate that the central nervous system of the locust contains at least two distinct classes of receptors. Subcellular fractionation experiments revealed that the receptor activity is enriched in the synaptosomal fraction. In the head as well as in the thoracic ganglia the nicotinic acetylcholine receptors were found to be much more abundant than the muscarinic binding sites; whereas in mouse brain the muscarinic receptor type predominates.     

Quinuclidinyl Benzilate Binding in House Fly Heads and Rat Brain

Abstract: House fly heads contain a binding site for 3-quinuclidinyl benzilate (QNB) that is quite similar in pharmacology to the muscarinic acetylcholine receptor of vertebrate tissues. The house fly site binds [³H]QNB reversibly with a K _d of 260 PM and B_max of 1 pmol/g of heads from direct binding measurements. The K_d calculated from the ratio of the dissociation rate constant (2 × 10⁻⁴ sec⁻¹) to the association rate constant (2.5 × 10⁶ M⁻¹ Sec⁻¹) was 80 pM. The house fly site binds (-)quinuclidinyl benzilate preferentially, as do classic muscarinic receptors. The binding is also sensitive to other muscarinic antagonists and agonists. Nicotinic and other drugs are no more effective on the house fly site than they are on the rat brain muscarinic receptor itself. These binding studies suggest that the house fly QNB binding site is a muscarinic receptor.     

丁氏双鳍电鳐电器官乙酰胆碱受体膜微囊的分离

本文报告了从丁氏双鳍电鳐电器官中分离纯化膜结合烟碱样乙酰胆碱受体的简便方法。比活性达1750nmolα-毒素结合点/克蛋白质,无乙酰胆碱酯酶活性,可避免它的干扰。电镜检查发现受体的膜结合物成微囊状,直径约0.1—0.3μα-毒素结合试验及聚丙烯酰胺凝胺电泳结果证明具有烟碱样胆碱能受体性质,适于受体功能和性质的研究。     

SELECTIVE PURIFICATION OF A SINGLE POPULATION OF GLUCOCORTICOID RECEPTORS FROM RAT BRAIN

Abstract— A 200-fold purification of glucocorticoid receptors from rat brain was achieved with 21% recovery using affinity chromatography via deoxycorticosterone hemisuccinate covalently coupled to BSA-Sepharose 4B. Subsequent chromatography of the affinity column eluate via a DE-52 anionexchanger revealed that this purification concerned selectively one of the two glucocorticoid receptor systems in rat brain.     

REGIONAL BIOSYNTHESIS OF ACETYLCHOLINE IN BRAIN FOLLOWING FORCED ORAL CHRONIC BARBITONE TREATMENT TO RAT

Rats received a solution of sodium barbitone as their only drinking fluid for 33 and 42–44 weeks. In three groups (A3, A12 and A30) the barbitone solution was withheld and replaced by water 3, 12 and 30 days respectively before death. Two other groups consisted of animals drinking barbitone until death (B) and untreated controls (C). Abstinence convulsions were recorded by jiggle cages. Thirty nmol of tritium-labelled choline ([³H]Ch) were injected i.v. and the rats were killed by decapitation 1 min later. A significantly higher content of tritium-labelled acetylcholine ([³H]ACh) was found in the cerebellum + medulla oblongata + midbrain of rats receiving barbitone until death (group B) (+22%) and abstinent for 3 days (+54%) (group A3) compared with group C. The [³H]ACh content was also significantly increased in the hippocampus + cortex of rats abstinent for 3 days (+23%). In the striatum no significant effect on [³H]ACh content was found in any of the groups. The ratio [³H]ACh/[³H]Ch was significantly increased in the cerebellum + medulla oblongata + midbrain of rats in group B and A3 and in the hippocampus + cortex in group A3. These results might indicate an increased turnover of ACh. The effect of long-term barbitone treatment on the enzyme activities of brain choline acetyltransferase and acetylcholinesterase was also studied but no significant effect was found.     

鼠脑少突胶质细胞三碘甲腺原氨酸（T＿3）受体的─过性表达

本实验采用三碘甲腺原氨酸（Ｔ３）核受体单抗和半乳糖脑苷酯（ＧＣ）多抗的双抗体免疾细胞化学法,观察了体外次生培养的大鼠脑少突胶质细胞成熟过程中核Ｔ３受体的表达。结果发现核Ｔ３受体主要存在于未成熟的少突胶质细胞中（阳性率约８０％）,而在成熟的少突胶质细胞中仅占４４％。这一现象可能是甲状腺激素在脑成熟过程中具有一段关键作用时期的分子机理之一。