哺乳动物促卵泡素氨基酸序列特征及其单克隆抗体的制备与鉴定

为制备哺乳动物促卵泡素(FSH)单克隆抗体,比对了人类、家畜、部分野生动物、鼠类等哺乳动物FSH氨基酸序列,分析其种间同源性,结果发现,多种哺乳动物FSHβ亚基氨基酸序列的同源性高于80%,且线性抗原表位高度保守。从奶牛垂体组织扩增FSHβ亚基CDS片段,构建p ET28aFSH重组质粒,诱导表达FSH重组蛋白,免疫Balb/c小鼠,取免疫小鼠的脾细胞与SP2/0骨髓瘤细胞融合,间接ELISA法筛选阳性杂交瘤细胞孔,取效价最高孔进行克隆和亚克隆,获得1株能够分泌抗FSH的单克隆抗体细胞株,命名为B4A5。B4A5细胞株经过数次传代培养、反复冻融后生长状态良好,且能够稳定分泌抗体。采用细胞株体外培养和小鼠腹水诱生法均制备了抗FSH的单克隆抗体,其效价分别为1∶640、1∶106。分别采用Western blot和间接ELISA法鉴定单克隆抗体的结合特异性和交叉反应性,结果显示,制备的单克隆抗体与FSH反应呈阳性,与促黄体素(LH)、促甲状腺素(TSH)、促乳素(PRL)、人绒毛膜促性腺激素(h CG)均无交叉反应性。综上,获得了1株能够稳定分泌单克隆抗体的杂交瘤细胞株,其分泌的单克隆抗体可特异性结合FSH蛋白。     

不同BMPRIB基因型小尾寒羊同期发情处理后FSHR和LHR表达量的研究

 【目的】根据小尾寒羊BMPRIB突变位点进行基因分型。研究发情期小尾寒羊BMPRIB基因型（BB、AB和AA）与FSHR和LHR mRNA表达量的关系。【方法】利用半定量PCR技术。【结果】在发情期BB型右侧卵巢FSHR 的mRNA水平（1.14±0.11）显著高于AA（0.44±0.11）和AB（0.36±0.08）型（P<0.01），但左侧卵巢在基因型间无显著性差异；BB型右侧卵巢LHR的mRNA水平（0.42±0.02）也显著高于AA（0.23±0.02）和AB（0.25±0.04）型（P<0.01），左侧卵巢各基因型间无显著性差异。【结论】FSHR和LHR的mRNA的高表达量可能是引起小尾寒羊较高的产羔数的原因之一。     

Crystal structure of a complex between the catalytic and regulatory (RIalpha) subunits of PKA

The 2.0-angstrom structure of the cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) catalytic subunit bound to a deletion mutant of a regulatory subunit (RIalpha) defines a previously unidentified extended interface. The complex provides a molecular mechanism for inhibition of PKA and suggests how cAMP binding leads to activation. The interface defines the large lobe of the catalytic subunit as a stable scaffold where Tyr247 in the G helix and Trp196 in the phosphorylated activation loop serve as anchor points for binding RIalpha. These residues compete with cAMP for the phosphate binding cassette in RIalpha. In contrast to the catalytic subunit, RIalpha undergoes major conformational changes when the complex is compared with cAMP-bound RIalpha. The inhibitor sequence docks to the active site, whereas the linker, also disordered in free RIalpha, folds across the extended interface. The beta barrel of cAMP binding domain A, which is the docking site for cAMP, remains largely intact in the complex, whereas the helical subdomain undergoes major reorganization.     

The alpha subunit of the GTP binding protein Gk opens atrial potassium channels

Guanine nucleotide binding (G) proteins (subunit composition alpha beta gamma) dissociate on activation with guanosine triphosphate (GTP) analogs and magnesium to give alpha-guanine nucleotide complexes and free beta gamma subunits. Whether the opening of potassium channels by the recently described Gk in isolated membrane patches from mammalian atrial myocytes was mediated by the alpha k subunit or beta gamma dimer was tested. The alpha k subunit was found to be active, while the beta gamma dimer was inactive in stimulating potassium channel activity. Thus, Gk resembles Gs, the stimulatory regulatory component of adenylyl cyclase, and transducin, the regulatory component of the visual system, in that it regulates its effector function--the activity of the ligand-gated potassium channel--through its guanine nucleotide binding subunit.     

A pituitary N-acetylgalactosamine transferase that specifically recognizes glycoprotein hormones

The glycoprotein hormones lutropin (LH) and follitropin (FSH), which have common alpha-subunits but hormone-specific beta-subunits, are both synthesized in the gonadotroph. However, they bear Asn-linked oligosaccharides that differ in structure. Those on LH terminate with the sequence SO4-4GalNAc beta 1----4GlcNAc beta 1----2Man alpha, whereas those on FSH terminate with the sequence sialic acid alpha-Gal beta 1----4GlcNAc beta 1----2Man alpha. A GalNAc-transferase was identified in bovine pituitary membranes that recognizes features of the alpha-subunit peptide and adds GalNAc to its oligosaccharides with an apparent Michaelis constant of 25 micromolar. The different patterns of glycosylation for LH and FSH indicate that access to the protein recognition marker on the alpha-subunit is modulated by the associated beta-subunit. The tightly regulated synthesis of sulfated and sialylated oligosaccharides on the pituitary glycoprotein hormones suggests these oligosaccharides have an important biological role.     

A mutation in the catalytic subunit of cAMP-dependent protein kinase that disrupts regulation

A mutant catalytic subunit of adenosine 3',5'-monophosphate (cAMP)-dependent protein kinase has been isolated from Saccharomyces cerevisiae that is no longer subject to regulation yet retains its catalytic activity. Biochemical analysis of the mutant subunit indicates a 100-fold decreased affinity for the regulatory subunit. The mutant catalytic subunit exhibits approximately a threefold increase in Michaelis constant for adenosine triphosphate and peptide cosubstrates, and is essentially unchanged in its catalytic rate. The nucleotide sequence of the mutant gene contains a single nucleotide change resulting in a threonine-to-alanine substitution at amino acid 241. This residue is conserved in other serine-threonine protein kinases. These results identify this threonine as an important contact between catalytic and regulatory subunits but only a minor contact in substrate recognition.     

抑制素主动免疫对母牛卵泡发育的影响

本试验以猪精液抑制素粗提物主动免疫母牛,研究了对母牛卵泡发育和内分泌的影响。免疫,母牛的卵泡发育率为１４５．５％,排卵率为１１８．２％,分别比对照组提高４５．５％和１８．２％。通过放射免疫法对免疫牛血液中ＦＳＨ,ＬＨ,Ｅ２水平测定发现,发情时免疫组母牛ＦＳＨ水平高于对照组,免疫组中多卵发育牛ＦＳＨ水平高于单卵牛,免疫组与对照组中ＬＨ水平相差不大,多卵牛发情时Ｅ２水平较高。     

6种石斑鱼成鱼的性腺发育、脑垂体结构以及垂体中FSHβ和LHβ细胞的免疫识别

以日本海域捕获的宝石石斑鱼(Epinephelus areolatus)、黑边石斑鱼(E.fasciatus)、赤点石斑鱼(E.akaara)、尾纹九棘鲈(Cephalopholis urodeta)、蜂巢石斑鱼(E.merra)和纹波石斑鱼(E.ongus)成鱼为对象,比较其性腺发育和脑垂体结构以及垂体中FSHβ和LHβ免疫信号的分布。结果表明:宝石石斑鱼、黑边石斑鱼、赤点石斑鱼和尾纹九棘鲈性腺发育为未成熟阶段,蜂巢石斑鱼和纹波石斑鱼性腺发育为成熟阶段。6种石斑鱼的脑垂体位于间脑腹面,由神经垂体(NH)和腺垂体(AH)组成。腺垂体从左至右进一步细分为前外侧部(RPD)、中外侧部(PPD)和中间部(PI)。在宝石石斑鱼、赤点石斑鱼和纹波石斑鱼中NH结构被PPD隔开分为上下两部分,而在黑边石斑鱼、尾纹九棘鲈和蜂巢石斑鱼中NH为一个整体。6种石斑鱼脑垂体中FSHβ和LHβ细胞的免疫信号主要分布在PPD和PI区域,且FSHβ信号强度均较LHβ强,推断在石斑鱼性腺发育成熟前后,FSHβ较LHβ重要。为石斑鱼的资源保护及人工繁殖方面提供基础生物学资料和理论依据。     

Defect in phosphorylation of insulin receptors in cells from an insulin-resistant patient with normal insulin binding

Mononuclear blood cells were obtained from a patient with type A insulin resistance. The cells showed a normal ability to bind iodine 125-labeled insulin. Analysis of solubilized insulin receptors from the patient's cells revealed a defect in insulin-stimulated tyrosine kinase activity, which is closely associated with the receptor itself. The enzyme failed to phosphorylate the insulin receptor and showed a markedly reduced ability to phosphorylate exogenously added substrates. It appears that receptors from this insulin-resistant patient have a defect distal to the insulin-binding site (the alpha subunit of the receptor). The defect could be located in the beta subunit, which has an adenosine triphosphate-binding site, or in another receptor component that transfers a signal of insulin binding into kinase activity. This dissociation between the normal binding and the defective protein kinase component of the insulin receptor represents the first biochemical defect of the receptor distal to ligand binding.     

Nesfatin-1对初情期雌性大鼠促性腺激素及其mRNA表达的影响

为探究侧脑室注射Nesfatin-1对雌性大鼠促性腺激素水平及其mRNA表达的影响,对初情期前雌性大鼠的侧脑室注射Nesfatin-1,采用实时荧光定量PCR法检测促黄体素(Luteinizing hormone,LH)和促卵泡素(Folliclestimulating hormone,FSH)mRNA在垂体中的变化,采用酶联免疫分析法检测血清LH和FSH的浓度。结果表明:在初情期前的雌性大鼠中,Nesfatin-1可促进初情期启动、增加卵巢重量、血清LH水平、垂体LH mRNA和FSH mRNA的表达增加(P0.05);但Nesfatin-1对FSH水平的影响不突出,注射后15min时增加(P0.05),60min不产生影响(P0.05)。侧脑室注射Nesfatin-1后15和60min均能提高血清LH水平,15min时提高更明显(P0.05),但对FSH水平的影响不尽相同。在成年的雌性大鼠中,Nesfatin-1对LH和FSH的分泌不产生影响(P0.05)。Nesfatin-1可通过下丘脑诱导和增强初情期过渡阶段雌性大鼠LH和FSH的释放及LH、FSH mRNA的表达。     

济宁青山羊发情周期内促性腺激素和性激素分泌规律的研究

本试验对处于繁殖季节的济宁青山羊进行颈静脉采血,用放射免疫分析法测定了血浆内促性腺激素(FSH、LH)和性激素(E2、P)的含量。结果表明:整个发情周期中FSH、LH和E2均先后出现4个分泌峰,FSH的4个分泌峰分别晚于LH峰2 d出现。E2的分泌峰除第3个分泌峰出现在第10天之外,其余3个峰均与LH峰同时出现。P在发情周期的第5天开始逐渐升高,间情期(第7~17天)维持在一个较高的水平(P>0.05),发情前一天(第18天)骤然下降。在发情期和间情期,FSH和LH分泌方式均呈脉冲式,E2和P为波动式分泌。发情期FSH的脉冲频率较间情期低(P>0.05),而LH的脉冲频率则高于间情期(P>0.05)。     

雌性鸭胚胎和雏鸭的抑制素和促性腺激素的分泌

测定了从孵化 ２１ ｄ 到出壳后 １ 日龄雌性鸭胚胎和初生雏 鸭外周及卵巢中具免疫活性的抑制素含量，同时也测定了促卵泡生成素（ Ｆ Ｓ Ｈ）和促黄体生成素（ Ｌ Ｈ）的含量⒚在判定有效后，用牛的抑制素放射免疫系统测定抑制素的含量⒚在第 ２１ 日至 ２５ 日时胚胎血浆中抑制素含量处于低水平， 到第 ２６ 日达到最大值，第 ２７ 日稍降后，抑制素含量在出生后快速下降⒚ Ｆ Ｓ Ｈ 含量在胚胎期无显著变化，其含量的变化与外周抑制素含量的变化相对独立⒚卵巢中抑制素含量在孵 化的第 ２５ 日有显著下降，并于第 ２６ 日时快速回升⒚卵巢和血浆中 抑制素的含量在整个研究阶段后者比前者高约 １０ 倍 ⒚血浆 Ｌ Ｈ 从第 ２１ 日开始下降，至第 ２５ 日 接着有所回升并于第 ２７ 日达第二峰值⒚总之，血浆抑制素和 Ｆ Ｓ Ｈ 在雌性鸭胚胎中不存在负反馈关系， 这预示着胚胎期抑 制素的主要作用 不是抑制垂体分 泌 Ｆ Ｓ Ｈ，同 样 Ｆ Ｓ Ｈ 也不影响抑 制素的分泌⒚     

Message transmission: receptor controlled adenylate cyclase system

The adenylate cyclase system is composed of an activating hormone or neurotransmitter (H), its receptor (R), the guanosine triphosphate (GTP) binding protein (Gs), and the catalytic unit (C). The activation of the receptor R involves a transient change in conformation, from a loose binding of the neurotransmitter H to an extremely tight interaction, termed locking. The system is regulated in the activation steps and also by three deactivation processes. A guanosine triphosphatase activity is built into the Gs protein so that the active GsGTP has only a limited lifetime during which it is able to activate C. In addition, the continued occupation of R by H causes desensitization of R. Finally, there are inhibitory receptors, such as alpha-adrenergic and opiate receptors, which inhibit the adenylate cyclase by way of a specific GTP binding protein (Gi). Yet to be determined are the conformational transformations of pure R on binding of an agonist or a partial agonist; the genes that code for the many different receptors that activate the adenylate cyclase, and the possibility that the G components interact with systems in the cell other than the adenylate cyclase.     

单色光对产蛋鸡血清中LH和FSH含量的影响

 【目的】研究单色光对外周血LH和FSH含量的影响，为阐明单色光对蛋鸡产蛋性能的作用机理提供科学依据。【方法】采用红、绿、蓝三种发光二级管和白炽灯，对蛋鸡进行光照，试验期19～53周龄，光强度15 lx,光照时间16h。【结果】25～34周龄段，蓝光组血清LH 和FSH值上升维持时间最长，峰值出现最晚。37～49周龄段，白光组LH值一直高于其它组，而40～49周龄，红光组LH和FSH值持续上升。在24h昼夜LH 和FSH分泌的变化中，白、蓝和红光组LH 和FSH值只有一个峰值， LH峰值分别出现在10、07和10h,而FSH 峰值出现在13、07和10h。绿光组LH 和FSH有3个峰值，均出现在07、16和01h。【结论】19～36周龄，蓝光促进LH和FSH的分泌， 37～53周龄，白光和红光促进LH和FSH的分泌，24h昼夜间各光组LH和FSH峰值（除白光组FSH外）均出现在上午。     

Domain separation in the activation of glycogen phosphorylase a

The crystal structure of glycogen phosphorylase a complexed with its substrates, orthophosphate and maltopentaose, has been determined and refined at a resolution of 2.8 angstroms. With oligosaccaride bound at the glycogen storage site, the phosphate ion binds at the catalytic site and causes the regulatory and catalytic domains to separate with the loss of stabilizing interactions between them. Homotropic cooperativity between the active sites of the allosteric dimer results from rearrangements in isologous contacts between symmetry-related helices in the subunit interface. The conformational changes in the core of the interface are correlated with those observed on covalent activation by phosphorylation at Ser14 (phosphorylase b----a).     

出雏至性成熟绍鸭卵巢FSH-R与LH-R mRNA表达的变化

用反转录多聚酶链式反应 (RT PCR)方法检测绍鸭出雏至 90日龄卵巢卵泡刺激素受体 (FSH R)和黄体生成素受体 (LH R)mRNA含量的变化。结果表明 ,卵巢FSH RmRNA水平在 30和 6 0日龄较高 ,且 30日龄时极显著高于 1和 90日龄 (P <0 0 1) ,与该阶段较高的卵巢相对生长速度相对应 ;而卵巢LH RmRNA水平随日龄逐渐升高 ,30、 6 0和 90日龄极显著高于 1日龄 (P <0 0 1) ,90日龄显著高于 30和 6 0日龄 (P <0 0 5 )。提示 :卵巢在早期发育阶段 ,尤其是快速增重期 ,对FSH的反应性较高 ;而接近性成熟时 ,可能由于卵泡发育的关系而对LH的反应性升高。     

p38MAPK信号通路选择性调节FSH对甾体生成 的诱导作用研究

利用乙烯雌酚(DES)处理23日龄SD大鼠,分离卵巢颗粒细胞(GC)进行无血清培养。结果表明,FSH(50ng/m1)处理GC,可迅速激活有丝分裂原蛋白激酶(p38MAPK),FSH处理5min便可观察到磷酸化的p38MAPK;FSH处理30min,磷酸化的p38MAPK水平达到最高;向培养液中加入H89(蛋白激酶A抑制剂,10μM),则显著抑制了FSH对p38MAPK的激活作用,提示这种激活作用依赖于蛋白激酶A(PKA)。用SB203580(p38MAPK抑制剂,20μM)抑制p38MAPK激活,则进一步提高了FSH对孕酮和甾体生成快速调节蛋白(StAR)的诱导作用,同时降低了FSH对雌激素生成的促进作用(p<0.01)。RT-PCR结果显示:抑制p38MAPK活性后,FSH对StARmRNA刺激作用明显增强,但对细胞色素P450芳香化酶(P450arom)mRNA的诱导作用却减弱了(p<0.05)。激光共聚焦和蛋白印迹结果显示:在GC中,StAR蛋白主要分布在线粒体中;与对照组相比,FSH显著提高了StAR的荧光强度和蛋白水平;抑制p38MAPK活性则增强了FSH对StAR蛋白表达的诱导作用。     

The alpha subunit of the GTP binding protein activates muscarinic potassium channels of the atrium

It has been debated whether the potassium channel of the atrium is activated by the alpha subunit or by the beta gamma subunits of guanine nucleotide binding (G) proteins, which dissociate on activation with guanosine triphosphate (GTP). Therefore, the channel-activating effectiveness of these subunits on isolated guinea pig atrial cells was tested. The activated alpha K subunit from human erythrocytes activated the channel in subpicomolar concentrations. The beta gamma dimer from bovine brain activated the channel in nanomolar concentrations. These results support the view that, physiologically, the alpha subunit activates the channel.     

不同激素对卵母细胞体外成熟培养的影响

本试验对比在成熟液中添加不同来源的促性腺激素,即进口的和国产的促性腺激素(FSH+LH)对山羊卵母细胞体外培养成熟效果的影响。二者对山羊卵母细胞成熟均有促进作用,卵母细胞成熟率都极显著高于对照组(P<0.01),分别为67.3%、68.9%和15.6%,但是它们之间的成熟率差异不显著(P>0.05)。国产激素成本低,使用方便,在卵母细胞体外成熟培养时,完全可以用国产的促性腺激素代替进口的FSH和LH。