孤啡肽——新发现的内阿片肽及其受体

孤啡肽是最近发现的一个１７肽,其结构与已知的内阿片肽,尤其是强啡肽Ａ类似;但具有明显不同的药理学特性;与经典的阿片受体结合能力很弱,而与阿片受体家族中的一个新成员－－“孤儿受体”结合能力很强,因而认为是该受体的天然配基,孤啡肽脑室注射可使小鼠痛觉过敏,运动减少。孤啡肽受体是阿片受体家族中的新成员,属于Ｇ蛋白偶联受体,与经典的阿片受体配基亲和力均很弱,该受体激活后介导对腺苷酸环化酶活力的抑制。     

猪脑抗吗啡镇痛肽的分离纯化及其抗血清对吗啡耐受影响的初步…

猪脑组织提取液经ＳｅｐｈａｄｅｘＧ－５０分子筛层析,Ｓ－ＳｅｐｈａｒｏｓｅＦａｓｔＦｌｏｗ阳离子交换柱层析及两次ＨＰＬＣ分离得到一分子量为１２０００,等电点ＰＩ７．１的多肽,并测定了其氨基酸组成和Ｎ末端部分序列：Ｎ－Ｐｈｅ－Ｌｙｓ－Ｇｌｙ－Ｐｈｅ－Ｐｒｏ－Ａｓｐ－Ａｓｐ／（Ｌｙｓ）－Ｌｙｓ／（Ａｓｐ）－Ａｓｐ－Ｔｙｒ,给昆明小鼠脑室注射或尾静脉注射肽均能抑制吗啡引起的镇痛作用,其作用随着注射剂量的     

孤啡肽在大鼠脑内对抗吗啡镇痛

脑内全新的阿片受体样受体（１９９４）及其内源性配体孤啡肽（１９９５）的发现形成了中枢神经系统阿片／抗阿片相互关系的研究领域中一个新的推动力。基于它们与阿片家族的高同源性及在脑内痛觉整合相关区域的丰富表达,本实验观察了ＯＦＱ在大鼠脑内对吗啡镇痛作用的影响。结果表明：（１）ＯＦＱ可以对抗脑室注射生理盐水引起的镇痛,后者可能是一种由内源性阿片系统介导的应激镇痛。（２）脑室注射ＯＦＱ在很大的剂量范围（４０     

镇痛多肽——内吗啡肽-1的人工合成及活性研究

 用液相合成方法合成了具有镇痛作用的μ阿片受体的内源性配体——内吗啡肽 - 1(endomorphin- 1 ) ,该四肽为 Tyr- Pro- Trp- Phe NH2 .液相合成法是在氨基酸的 N端用 Boc(叔丁氧羰酰基 )作保护基 ,C端用 HOSu(N-羟基琥珀酰亚胺 )活化 ,与未加保护基的氨基酸在碱性条件下接肽 .先分别合成 C端二肽和 N端二肽 ,再缩合为四肽 ,产物的保护基用盐酸脱帽去除 .中间产物用薄层层析和熔点鉴定其纯度 ,最终得到了高纯度的四肽 .小白鼠脑室注射 (i.c.v)测定表明 ,8.2 5nmol剂量给药 ,其镇痛活性为 87% ,明显高于吗啡 (morphine) .     

阿片肽研究的回顾与展望

阿片肽研究已有２０多年历史,１９６２年中国学者提出脑内存在吗啡有效作用位点的创见。７０年代期间,先后发现各类阿片受体以及脑啡肽、β－内啡肽和强啡肽等阿片肽。９０年代初,各类阿片受体的基因 克隆成功,随后又发现了孤啡肽,当前阿片肽研究正在继续。阿片受体的基因剔除、计算机的模拟结构分析、阿片类物质的镇痛与成瘾机制、寻找新的阿片肽及受体的基因克隆等均在深入进行。     

半导体激光针对中枢及外周内阿片肽神经递质的影响

本工作应用半导体激光６５０ｎｍ １０ｍＷ ＣＷ照射“扶突”穴，发现Ｌ－ＥＮＫ除在尾核区有非常显著的增加外，而在海马，丘脑，下丘脑则都有不同程度的下降，其显著性Ｐ值分别为Ｐ〈０．０５，Ｐ〈０；０１，Ｐ〈０．０１。在外周血浆中Ｌ－ＥＮＫ则亦有显著的增加。     

海藻酸钠-壳聚糖固定化木瓜蛋白酶催化内吗啡肽的合成

反应体系以乙腈作为有机介质,在微水有机溶剂体系中以Boc-Trp-OH和Phe-NH2为底物,用海藻酸钠 壳聚糖固定化木瓜蛋白酶催化合成Trp-Phe-NH2时,产率为27.8%．在这一合成反应中,对pH值、离子强度、溶液含量、反应温度、酶用量和反应时间进行正交试验,证明pH是本合成过程的最重要影响因素．反应体系以乙腈为有机介质,在微水有机溶剂体系中以 Boc-Tyr-Pro-OMe和Trp-Phe-NH2为底物,用IPSAC催化合成Tyr-Pro-Trp-Phe-NH2,产率为35~2%．     

电针镇痛时大鼠外侧网状旁巨细胞核中内阿片肽的变化

本文应用放射免疫测定的方法观察了大鼠外侧网状旁巨细胞核(RPGL)推挽灌流液中内阿片肽含量在针刺前后的变化。结果表明:电针组动物经电针20min后,RPGL灌流液中亮氨酸脑啡肽(LEK)的含量显著高于对照组(P<0.05)。高针效组动物电针后RPGL灌流液中β-内啡肽(β-EP)的含量显著高于对照组(P<0.05),而低针效组动物电针后β-EP的含量有减少趋势。动物电针后痛阈的升高与RPGL中LEK及β-EP的含量增多呈正相关(P<0.05);电针20min后动物RPGL灌流液中强啡肽A_(1-13)(DynA(1-13))的含量与对照组比较仅显示一微小的增加(P>0.05)。结果提示,电针时RPGL中LEK及β-EP的释放增加可能与针刺镇痛有关。     

猪脑抗吗啡镇痛肽的分离纯化及其抗血清对吗啡耐受影响的初步研究

猪脑组织提取液经SephadexG-50分子筛层析,S-SepharoseFastFlow阳离子交换柱层析及两次HPLC分离得到一分子量为12000,等电点pI7．1的多肽,并测定了其氨基酸组成和N末端部分序列：N-phe-Lys-Gly-Phe-Pro-Asp-Asp／（Lys）-Lys／（Asp）-Asp-Tyr．给昆明小鼠脑室注射或尾静脉注射该肽均能抑制吗啡引起的镇痛作用,其作用随着注射剂量的增大而增强．用BALB／C小鼠制备了该肽的抗血清,脑室注射此抗血清能明显逆转昆明小鼠对吗啡的耐受．因为这种来自猪脑的具有抗阿片镇痛作用的肽有99个氨基酸,所以简称此肽为AOP-99a（anti-oPioidpeptide）．     

吗啡的精神神经免疫学作用及灵芝多糖肽对吗啡依赖小鼠的免疫保护效应

通过多种急慢性吗啡给药动物模型,从整体,细胞和分子水平,系统研究了吗啡的精神神经免疫学作用及灵芝多糖肽对吗啡依赖小鼠的免疫保护效应,首次发现：反复吗啡处理小鼠脾细胞内原癌基因ｃ－ｍｙｂ和ｃ－ｍｙｃ的表达比正常动物降低;ＧＰＰ可以明显恢复吗啡处置小鼠降低的各项免疫学实验指标达到甚至超出对照水平,从而为应用ＧＰＰ等免疫反应修饰剂控制阿片滥用所致的免疫功能缺陷提供了动物实验依据。     

Multiple ligands in opioid research

The observation in 1979 that opioid receptors interact, led to the design of bivalent ligands in an attempt to improve selectivity and affinity towards the different subtypes( i.e. mu, delta, and kappa). Dimers of monovalent 'parent' opioid structures have been evaluated and include: (a) endogenous (e.g enkephalins) or exogenous (e.g dermorphin) peptide dimer analogues (b) mixed peptidic -non-peptidic bivalent ligands and (c) dual non-peptidic dimers. Chimeric structures, using an opioid pharmacophore in combination with a a non-opioid pharmacophore, have also been prepared. The common aim in all these studies is to improve the pharmacological profile of potential analgesics to minimize common opioid-induced side effects, such as physical dependence and tolerance. Here we present a brief overview efforts to develop bivalent opioid ligands for use in pain-related research.     

Molecular modeling studies to predict the possible binding modes of endomorphin analogs in μ opioid receptor

The molecular docking of a series of endomorphin analog with the μ opioid receptor was performed. The successive molecular dynamics of several proposed ligand–receptor complexes inserted into the phospholipid bilayer were carried out to optimize the complex and explore the conformational changes. Meaningful differences of their binding modes were detected and the involvement of some essential residues in ligand binding was also identified. Our proposed ligand–receptor model is in good agreement with previous site-directed mutagenesis experiments.     

污染物降解成为环境微生物领域研究的重点

<正>根据《微生物学通报》2013年发表的文章分析,环境微生物学领域的论文有32篇,平均每个月在2篇以上,论文数显著多于农业微生物学(20篇)和工业微生物学(18篇)及其他领域。然而,在环境微生物学领域中,有关污染物降解方面的文章达到了12篇。就本刊数据而言,这体现了污染物的降解已成为我国环境微生物学研究领域的重点。其中有10项研究工作,针对各种有机化合物的处理与降解,如石油[1]、包     

Azidomorphine is an agonist of high-affinity opioid receptor binding sites

Azidomorphine at low concentration (10^–9 M) inhibits the high-affinity binding site of labeled naloxone in rat brain membrane preparations. In the presence of Na⁺ and guanine nucleotides the displacement curves of azidomorphine are increased toward high concentrations, whereas Mg²⁺ ions decrease the IC₅₀ values; This demonstrates the agonist behavior of azidomorphine in binding experiments. When compared with morphine, azidomorphine displayed five-fold lower IC₅₀ values. Based on the presented results, azidomorphine appears to be a good candidate for photoaffinity labeling of opiate receptors.     

Endomorphin-2 is an endogenous opioid in primary sensory afferent fibers

Evidence is presented that the recently discovered endogenous mu-selective agonist, endomorphin-2, is localized in primary sensory afferents. Endomorphin-2-like immunoreactivity was found to be colocalized in a subset of substance P- and mu opiate receptor-containing fibers in the superficial laminae of the spinal cord and spinal trigeminal nucleus. Disruption of primary sensory afferents by mechanical (deafferentation by dorsal rhizotomy) or chemical (exposure to the primary afferent neurotoxin, capsaicin) methods virtually abolished endomorphin-2-like immunoreactivity in the dorsal horn. These results indicate that endomorphin-2 is present in primary afferent fibers where it can serve as the endogenous ligand for pre- and postsynaptic mu receptors and as a major modulator of pain perception.     

Leaf litter is an important mediator of soil respiration in an oak-dominated forest

The contribution of the organic (O) horizon to total soil respiration is poorly understood even though it can represent a large source of uncertainty due to seasonal changes in microclimate and O horizon properties due to plant phenology. Our objectives were to partition the CO₂ effluxes of litter layer and mineral soil from total soil respiration (SR) and determine the relative importance of changing temperature and moisture mediating the fluxes. We measured respiration in an oak-dominated forest with or without the O horizon for 1 year within the Oak Openings Region of northwest Ohio. Mineral soil and O horizon respiration were subtracted from mineral soil respiration (MSR) to estimate litter respiration (LR). Measurements were grouped by oak phenology to correlate changes in plant activity with respiration. The presence of the O horizon represented a large source of seasonal variation in SR. The timing of oak phenology explained some of the large changes in both SR and LR, and their relationship with temperature and moisture. The contribution to SR of respiration from the mineral soil was greatest during pre-growth and pre-dormancy, as evident by the low LR:MSR ratios of 0.65 ± 0.10 (mean ± SE) and 0.69 ± 0.03, respectively, as compared to the other phenophases. Including moisture increased our ability to predict MSR and SR during the growth phenophase and LR for every phenophase. Temperature and moisture explained 85% of the variation in MSR, but only 60% of the variation in LR. The annual contribution of O horizon to SR was 48% and the ratio of litter to soil respiration was tightly coupled over a wide range of environmental conditions. Our results suggest the presence of the O horizon is a major mediator of SR.     

D-Erythroascorbic acid is an important antioxidant molecule in Saccharomyces cerevisiae

D-Arabinono-1,4-lactone oxidase catalysing the final step of D-erythroascorbic acid biosynthesis was purified from the mitochondrial fraction of Saccharomyces cerevisiae. Based on the amino acid sequence analysis of the enzyme, an unknown open reading frame (ORF), YML086C, was identified as the ALO1 gene encoding the enzyme. The ORF of ALO1 encoded a polypeptide consisting of 526 amino acids with a calculated molecular mass of 59493Da. The deduced amino acid sequence of the enzyme shared 32% and 21% identity with that of L-gulono-1,4-lactone oxidase from rat and L-galactono-1,4-lactone dehydrogenase from cauliflower, respectively, and contained a putative transmembrane segment and a covalent FAD binding site. Blot hybridization analyses showed that a single copy of the gene was present in the yeast genome and that mRNA of the ALO1 gene was 1.8kb in size. In the alo1 mutants, D-erythroascorbic acid and the activity of D-arabinono-1,4-lactone oxidase could not be detected. The intracellular concentration of D-erythroascorbic acid and the enzyme activity increased up to 6.9-fold and 7.3-fold, respectively, in the transformant cells carrying ALO1 in multicopy plasmid. The alo1 mutants showed increased sensitivity towards oxidative stress, but overexpression of ALO1 made the cells more resistant to oxidative stress.