绵羊 PGRMC1 蛋白的cDNA克隆、序列分析及组织表达

\t\t\t\t\t目的\t\t\t\t\t孕激素受体膜组分1 (PGRMC1)在动物繁殖活动中有重要调节作用,本研究旨在探讨牦牛PGRMC1基因的序列及其在生殖轴的组织表达特性。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t方法\t\t\t\t\t试验采集5头牦牛和5头黄牛的下丘脑、脑垂体、卵巢、输卵管和子宫,以GenBank上已发布的普通牛PGRMC1基因序列设计引物,采用RT-PCR方法克隆牦牛和黄牛的PGRMC1基因,并使用相关的生物信息学软件对克隆所得序列进行分析;采用qRT-PCR法检测该基因在牦牛和黄牛不同组织中的表达情况。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t结果\t\t\t\t\t结果得到牦牛和黄牛PGRMC1基因cDNA序列(GenBank登录号：MF803753 和MF803754),编码区(CDS)全长都为585 bp,编码 194 个氨基酸。其编码蛋白中含有1个 Cyt-b5 保守结构域。qRT-PCR结果表明：PGRMC1基因在牦牛和黄牛下丘脑、脑垂体、卵巢、输卵管和子宫都有表达,牦牛和黄牛的垂体中的PGRMC1的表达差异显著(P<0.05),但在其他组织品种间差异不显著;牦牛PGRMC1在卵巢和垂体的表达量显著高于其他组织(P<0.05)。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t结论\t\t\t\t\t本研究提示PGRMC1基因可能在牦牛卵泡发育、发情、排卵等繁殖机能调控中发挥重要作用。\t\t\t\t\t\t\t\t\t     

Temperature and charge transfer in a receptor membrane

The rate of rise and the amplitude of a mechanically elicited generator potential in a receptor membrane (Pacinian corpuscle) increases markedly with temperature. By contrast, the amplitude of the action potential of the Ranvier node adjacent to the receptor membrane remains practically unchanged over a wide range of temperature. The activation energy of the rate-limiting process in excitation of the receptor membrane is high; it indicates the existence of a high potential energy barrier for charge transfer.     

A G protein-coupled receptor is a plasma membrane receptor for the plant hormone abscisic acid

The plant hormone abscisic acid (ABA) regulates many physiological and developmental processes in plants. The mechanism of ABA perception at the cell surface is not understood. Here, we report that a G protein-coupled receptor genetically and physically interacts with the G protein alpha subunit GPA1 to mediate all known ABA responses in Arabidopsis. Overexpressing this receptor results in an ABA-hypersensitive phenotype. This receptor binds ABA with high affinity at physiological concentration with expected kinetics and stereospecificity. The binding of ABA to the receptor leads to the dissociation of the receptor-GPA1 complex in yeast. Our results demonstrate that this G protein-coupled receptor is a plasma membrane ABA receptor.     

脑梗死肝阳化风证与阴虚风动证蛋白质组学 比较研究

目的建立脑梗死肝阳化风证与阴虚风动证血清双向凝胶电泳图谱,初步分析其差异蛋白质表达情况。 方法双向凝胶电泳(2-DE)分离脑梗死肝阳化风证与阴虚风动证血清标本,考马斯亮兰染色,PD-QUEST 图像分析系 统分析,从凝胶中选取分离较好的蛋白质点,基质辅助激光解析电离飞行时间质谱(MALDI-TOF-MS)分析获取肽质 量指纹图谱（PMF）,Mascot 软件搜索SWISS-PROT 数据库鉴定蛋白质,对差异蛋白质进行组间对比。结果获得了分 辨率较好的脑梗死肝阳化风证与阴虚风动证双向凝胶电泳图谱,质谱分析了29 个差异蛋白质点,获取了87 张肽质 量指纹图谱,通过查询数据库鉴定了29 个蛋白质,其中部分蛋白质与肝阳化风证及阴虚风动证发生发展有关。结论 建立了脑梗死肝阳化风证与阴虚风动证血清双向凝胶电泳图谱,并应用质谱技术鉴定了部分差异蛋白质点,为脑梗 死肝阳上亢证与阴虚风动证与正常组血清双向凝胶电泳图谱血清蛋白质组数据库的建立提供了有意义的数据,并认 为蛋白质组学能在脑梗死不同证型具有代表意义。     

Odor-induced membrane currents in vertebrate-olfactory receptor neurons

In olfactory receptor neurons, odor molecules cause a depolarization that leads to action potential generation. Underlying the depolarization is an ionic current that is the earliest electrical event in the transduction process. In two preparations, olfactory receptor neurons were voltage-clamped and stimulated with odors and this generator current was measured. In addition, a method was developed to estimate the time course and absolute concentration of odorants delivered to the receptor sites. With this method, olfactory neurons were found to have relatively high stimulus thresholds, steep dose-response relations, long latencies, and an apparent requirement for cooperativity at one or more steps in the pathway from odorant binding to activation of the generator current.     

Deficit in attachment behavior in mice lacking the mu-opioid receptor gene

Endogenous opioid binding to micro receptors is hypothesized to mediate natural rewards and has been proposed to be the basis of infant attachment behavior. Here, we report that micro-opioid receptor knockout mouse pups emit fewer ultrasonic vocalizations when removed from their mothers but not when exposed to cold or male mice odors. Moreover these knockout pups do not show a preference toward their mothers' cues and do not show ultrasonic calls potentiation after brief maternal exposure. Results from this study may indicate a molecular mechanism for diseases characterized by deficits in attachment behavior, such as autism or reactive attachment disorder.     

Comment on "A G protein coupled receptor is a plasma membrane receptor for the plant hormone abscisic acid"

Liu et al. (Reports, 23 March 2007, p. 1712) reported that the Arabidopsis thaliana gene GCR2 encodes a seven-transmembrane, G protein-coupled receptor for abscisic acid. We argue that GCR2 is not likely to be a transmembrane protein nor a G protein-coupled receptor. Instead, GCR2 is most likely a plant homolog of bacterial lanthionine synthetases.     

Catecholamine-induced alteration in sedimentation behavior of membrane bound beta-adrenergic receptors

Incubation of astrocytoma cells with catecholamines results in a decrease in catecholamine-stimulated adenylate cyclase activity and a concomitant alteration in the sedimentation properties of particulate beta-adrenergic receptors. The altered receptors exhibit agonist binding properties similar to those of receptors that are "uncoupled" from adenylate cyclase.     

杀伤细胞免疫球蛋白样受体在输血中的作用

目的 初步探讨杀伤细胞免疫球蛋白样受体在输血中的作用.方法 用免疫磁珠法分离正常人外周血NK细胞,再用PCR-SSP方法进行KIR分型.将分型的NK细胞与已知HLA分型的全血混合,37℃培养0、6、12、24h,ELISA法检测IL-2、IL-4、前列腺素E2(PGE2)、TNF-α、TNF-β、IFN-γ、粒细胞-巨...     

Role of phosphatidylinositol kinase in PDGF receptor signal transduction

The molecules with which the platelet-derived growth factor (PDGF) receptor interacts to elicit the biochemical reactions responsible for cell proliferation have not been identified. Antisera directed against specific PDGF receptor peptides coprecipitated a phosphatidylinositol (PI) kinase and the PDGF receptor. Immunoprecipitates from PDGF-stimulated cells contained 10 to 50 times as much PI kinase as those from unstimulated cells. Mutation of the PDGF receptor by deletion of its kinase insert region resulted in a receptor markedly less effective than the wild type in eliciting cell proliferation and defective in PDGF-stimulated PI kinase, but still capable of PDGF-induced receptor autophosphorylation and phosphoinositide hydrolysis. These data show that the PDGF receptor is physically associated with a PDGF-sensitive PI kinase that is distinct from tyrosine kinase and is not required for PDGF-induced PI hydrolysis. The finding that the mutant PDGF receptor missing the kinase insert domain elicited known early biochemical responses to PDGF, but did not associate with or regulate PI kinase, suggests a novel role for the receptor-associated PI kinase in the transmission of mitogenic signals.     

Quantitative imaging of lateral ErbB1 receptor signal propagation in the plasma membrane

Evidence for a new signaling mechanism consisting of ligand-independent lateral propagation of receptor activation in the plasma membrane is presented. We visualized the phosphorylation of green fluorescent protein (GFP)-tagged ErbB1 (ErbB1-GFP) receptors in cells focally stimulated with epidermal growth factor (EGF) covalently attached to beads. This was achieved by quantitative imaging of protein reaction states in cells by fluorescence resonance energy transfer (FRET) with global analysis of fluorescence lifetime imaging microscopy (FLIM) data. The rapid and extensive propagation of receptor phosphorylation over the entire cell after focal stimulation demonstrates a signaling wave at the plasma membrane resulting in full activation of all receptors.     

Role of brain insulin receptor in control of body weight and reproduction

Insulin receptors (IRs) and insulin signaling proteins are widely distributed throughout the central nervous system (CNS). To study the physiological role of insulin signaling in the brain, we created mice with a neuron-specific disruption of the IR gene (NIRKO mice). Inactivation of the IR had no impact on brain development or neuronal survival. However, female NIRKO mice showed increased food intake, and both male and female mice developed diet-sensitive obesity with increases in body fat and plasma leptin levels, mild insulin resistance, elevated plasma insulin levels, and hypertriglyceridemia. NIRKO mice also exhibited impaired spermatogenesis and ovarian follicle maturation because of hypothalamic dysregulation of luteinizing hormone. Thus, IR signaling in the CNS plays an important role in regulation of energy disposal, fuel metabolism, and reproduction.     

Papain membrane on a collodion matrix: preparation and enzymic behavior

A stable papain membrane has been prepared on a collodion matrix by absorbing papain in a collodion membrane and then cross-linking the papain with bisdiazobenzidine 3,3'-disulfonic acid. The pH-dependence of the activity of the enzyme membrane on the low-molecular-weight substrate, benzoylarginine ethyl ester, was found to differ from that of crystalline papain; the activity was low in the neutral pH range where the native enzyme has its optimum and high at alkaline pH. This anomalous behavior is due to a lowering of the local pH within the membrane as a result of the release of acid by the enzymic hydrolysis of the ester substrate.     

A membrane receptor for retinol binding protein mediates cellular uptake of vitamin A

Vitamin A has diverse biological functions. It is transported in the blood as a complex with retinol binding protein (RBP), but the molecular mechanism by which vitamin A is absorbed by cells from the vitamin A-RBP complex is not clearly understood. We identified in bovine retinal pigment epithelium cells STRA6, a multitransmembrane domain protein, as a specific membrane receptor for RBP. STRA6 binds to RBP with high affinity and has robust vitamin A uptake activity from the vitamin A-RBP complex. It is widely expressed in embryonic development and in adult organ systems. The RBP receptor represents a major physiological mediator of cellular vitamin A uptake.     

Role of NMDA receptor subtypes in governing the direction of hippocampal synaptic plasticity

Activation of N-methyl-d-aspartate subtype glutamate receptors (NMDARs) is required for long-term potentiation (LTP) and long-term depression (LTD) of excitatory synaptic transmission at hippocampal CA1 synapses, the proposed cellular substrates of learning and memory. However, little is known about how activation of NMDARs leads to these two opposing forms of synaptic plasticity. Using hippocampal slice preparations, we showed that selectively blocking NMDARs that contain the NR2B subunit abolishes the induction of LTD but not LTP. In contrast, preferential inhibition of NR2A-containing NMDARs prevents the induction of LTP without affecting LTD production. These results demonstrate that distinct NMDAR subunits are critical factors that determine the polarity of synaptic plasticity.     

Physiological constraint on feeding behavior: intestinal membrane disaccharidases of the starling

Animals clearly choose what they eat and can even choose among chemically different sugars. The physiological and biochemical mechanisms that constrain feeding choices are largely unknown. In this study, European starlings (Sturnus vulgaris) preferred mixture solutions of D-glucose plus D-fructose to equimolar (double molar caloric value) solutions of sucrose. Intubation feeding of sucrose did not increase blood glucose levels. Sucrose is a useless energy source for these birds because they lack a single digestive enzyme (sucrase) on the small intestinal brush border membrane. However, the membranes possessed separate maltase and isomaltase disaccharidases. This expression pattern and expression patterns of membrane disaccharidases among mammals suggest a role for intestinal enzymes in the coevolutionary interactions between vertebrates and their plant food sources.     

Role of adaptor TRIF in the MyD88-independent toll-like receptor signaling pathway

Stimulation of Toll-like receptors (TLRs) triggers activation of a common MyD88-dependent signaling pathway as well as a MyD88-independent pathway that is unique to TLR3 and TLR4 signaling pathways leading to interferon (IFN)-beta production. Here we disrupted the gene encoding a Toll/IL-1 receptor (TIR) domain-containing adaptor, TRIF. TRIF-deficient mice were defective in both TLR3- and TLR4-mediated expression of IFN-beta and activation of IRF-3. Furthermore, inflammatory cytokine production in response to the TLR4 ligand, but not to other TLR ligands, was severely impaired in TRIF-deficient macrophages. Mice deficient in both MyD88 and TRIF showed complete loss of nuclear factor kappa B activation in response to TLR4 stimulation. These findings demonstrate that TRIF is essential for TLR3- and TLR4-mediated signaling pathways facilitating mammalian antiviral host defense.