984 resultados para Argó


Relevância:

10.00% 10.00%

Publicador:

Resumo:

A novel disintegrin, jerdonatin, was purified to homogeneity from Trimeresurus jerdonii venom by gel filtration and reversed-phase high-pressure liquid chromatography. We isolated the cDNA encoding jerdonatin from the snake venom gland. Jerdonatin cDNA precursor,;encoded pre-peptide, metalloprotease and disintegrin domain. Jerdonatin is composed of 72 amino acid residues including 12 cysteines and the tripeptide sequence Arg-Gly-Asp (RGD), a well-known characteristic of the disintegrin family. Molecular mass of jerdonatin was determined to be 8011 Da by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS). Jerdonatin inhibited ADP- and collagen-induced human platelet aggregation with IC50 of 123 and 135 nM, respectively. We also investigated the effect of jerdonatin on the binding of B6D2F1 hybrid mice spermatozoa to mice zona-free eggs and their subsequent fusion. Jerdonatin significantly inhibited sperm-egg binding in a concentration-dependent manner, but had no effect on the fusion of sperm-egg. These results indicate that integrins on the egg play a role in mammalian fertilization. (C) 2004 Elsevier Inc. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

通过70%冷甲醇抽提、Sephadex C i-15分子筛和反相高效液相色谱G8层析,从湖南产烙铁头蛇毒(Trineresurus muqua nwtus)冻干粉中纯化得到一个新的舒缓激肤增强肤(BPP),命名为TmF。该小肤的氨基酸序列为p(irr (iy Arg Pro, Leti (iy Pro, Pro, Ile- Pro, Pro ( pau表示焦谷氨酸)。序列结果分析表明,TmF和已经分离得到的BPPs有很高的序列同源性。MSI- MS 测定其分子量为1 .1107 kD o TmF的生物学活性和药理学活性检测的结果表明,它增强舒缓激肤(BK)(1 mg/L)诱导的离体豚 鼠回肠纵行肌收缩的活性为(1 .13士0 .3)单位(mg/ L) ; TmF (5 .0 x 10- 0 mg/ kg)可以增强约(14士2) mmHg的由BK(5 . Ox 10-' mg/ kg)诱导的舒张压下降;在抑制剂试验中,不同剂量的TmF和5x1。一zmg的血管紧张素转化酶保温30 min,结果表明大约 2.0x10一3mg的TmF表现出对ACE水解活性的半数抑制率(IQo )。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The phylogeny of Chinese leaf monkeys, especially the snub-nosed monkeys (Rhinopithecus), has not been thoroughly investigated using molecular sequence data, perhaps due to their rarity in the wild and their poor representation in institutional collections. Despite several proposed classifications, systematic relationships of these species remain poorly defined and this has hindered their conservation. To clarify the phylogenetic relationships of the leaf monkey clade in China, we sequenced the mitochondrial ND3, ND4L, ND4, tRNA(Arg), tRNA(His), tRNA(Ser), and tRNA(Leu) genes for Rhinopithecus bieti, R. roxellana, Trachypithecus francoisi, T. f. leucocephalus, and T. phayrei as well as Pygathrix nemaeus and Colobus guereza. We included a rotal of 2252 characters for each individual, excluding gaps in primary sequences. Our interpretation of the results from character- and distance-based phylogenetic analyses suggest that (1) Pygathrix nemaeus is sister to Rhinopithecus rather than to Trachypithecus though it is quite divergent from the former; (2) the Yunnan snub-nosed monkey, Rhinopithecus bieti, represents a valid species; (3) the white-headed leaf monkey is not a distinct species, but instead is a subspecies of Trachypithecus francoisi (T. f. leucocephalus), though it should still be considered a separate evolutionarily significant unit (ESU); and (4) because two individuals of the Phayrei's leaf monkey, T. phayrei, are genetically distinct from one another, a more extensive revision of the taxonomy of this putative species in China is needed. These results, plus ongoing work on the molecular systematics of the entire Asian leaf monkey radiation, can provide a sound basis for identifying the appropriate units of conservation for this endangered group of primates.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A novel bradykinin-potentiating peptide (BPP), designated as TmF, has been purified to homogeneity from the venom of Trimeresurus mucrosquamatus by 70% cold methanol extraction, Sephadex G-15 gel filtration and reverse-phase high performance liquid chromatography (RP-HPLC). The amino acid sequence of TmF was determined to be pGlu-Gly-Arg-Pro-Leu-Gly-Pro-Pro-Ile-Pro-Pro (pGlu denotes pyroglutamic acid), which shared high homology with other BPPs. The molecular mass of TmF was 1.1107 kD as determinated by electrospray ionization-mass spectrometry (ESI-MS), which was in accordance with the calculated value of 1.1106 kD. The potentiating "unit" of TmF to bradykinin-induced (BK-induced) contraction on the guinea-pig ileum in vitro was (1.13 +/- 0.3) unit (mg/L), and TmF (5.0 x 10(-4) mg/kg) increased the pressure-lowering-effect of bradykinin (5.0 x 10(-5) mg/kg) with approximate descent value of (14 +/- 2) mmHg. In addition, TmF inhibited the conversion of angiotensin I to angiotensin 11, 2 x 10(-3) mg of TmF caused 50% inhibition (IC50) of angiotensin-converting enzyme (ACE) hydrolyzing activity to bradykinin.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

应用高效液相色谱(HPLC)技术,首次测定了湖北石首长江天鹅州白豚自然保护区野生长江江豚(Neopho-caena phocaenoides asiaeorientalis)和中国科学院水生生物研究所白豚馆人工饲养的长江江豚血清中17种氨基酸的含量。结果表明,除了脯氨酸Pro、蛋氨酸Met和组氨酸His外,人工饲养江豚血清中其余14种氨基酸(天门冬氨酸Asp、谷氨酸Glu、丝氨酸Ser、精氨酸Arg、甘氨酸Gly、苏氨酸Thr、丙氨酸Ala、异亮氨酸Ile、亮氨酸Leu、苯丙氨酸Phe、缬氨酸Val、赖氨

Relevância:

10.00% 10.00%

Publicador:

Resumo:

以野外收集的水华蓝藻为原料,经过75%甲醇溶液浸提,快速色谱分离和半制备色谱纯化,从滇池水华蓝藻中分离纯化出1种微囊藻毒素变体.电喷雾质谱、紫外分光光度计和HPLC检测结果表明,所得毒素为[Dha7]MCRR,是MCRR的1种去甲基化变体,其纯度大于95%.该毒素的分子组成为环(Ala-Arg-MeAsp-Arg-Adda-Glu-Dha),分子量为1 023,其紫外扫描光谱(200~300 nm)在239 nm处有特征吸收.[Dha7]MCRR在滇池水华蓝藻中普遍存在,有时会成为MC的主要种类.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Cell-material interactions are crucial for cell adhesion and proliferation on biomaterial surfaces. Immobilization of biomolecules leads to the formation of biomimetic substrates, improving cell response. We introduced RGD (Arg-Gly-Asp) sequences on poly-ε-caprolactone (PCL) film surfaces using thiol chemistry to enhance Schwann cell (SC) response. XPS elemental analysis indicated an estimate of 2-3% peptide functionalization on the PCL surface, comparable with carbodiimide chemistry. Contact angle was not remarkably reduced; hence, cell response was only affected by chemical cues on the film surface. Adhesion and proliferation of Schwann cells were enhanced after PCL modification. Particularly, RGD immobilization increased cell attachment up to 40% after 6 h of culture. It was demonstrated that SC morphology changed from round to very elongated shape when surface modification was carried out, with an increase in the length of cellular processes up to 50% after 5 days of culture. Finally RGD immobilization triggered the formation of focal adhesion related to higher cell spreading. In summary, this study provides a method for immobilization of biomolecules on PCL films to be used in peripheral nerve repair, as demonstrated by the enhanced response of Schwann cells.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

以野外收集的水华蓝藻为原料,建立了以75%甲醇溶液提取、快速色谱和半制备色谱分离为主要步骤的微囊藻毒素分离纯化方法,并用HPLC、分光光度计和电喷雾质谱对所得毒素的纯度和结构进行了鉴定.结果表明,所得毒素为MCRR,纯度大于95%,其紫外吸收光谱在239nm处有特征吸收,分子组成为环(Ala-Arg-MeAsp-Arg-Adda-Glu-Mdha),分子量为1037.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

促性腺激素释放激素(GnRH)是一个保守的神经十肽家族,在调节脊椎动物的性腺发育和控制性成熟中起至关重要的作用.用RACE和RT-PCR方法,从鲤鱼脑组织克隆得到两个差异的cGnRH-Ⅱ cDNAs序列,其长度分别为622,578 bp.两个cDNA编码的cGnRH-Ⅱ前体均为86个氨基酸,包括一个信号肽、cGnRH-Ⅱ十肽和一个由蛋白水解位点(Gly-Lys-Arg)连接的GnRH相关肽.内含子捕获和Southern杂交证实鲤鱼基因组中有两个cGnRH-Ⅱ编码基因,且两个基因都可能以单拷贝形式存在.鲤鱼

Relevância:

10.00% 10.00%

Publicador:

Resumo:

采用RACE方法 ,从鲤鱼脑组织克隆了两个差异的sGnRH(salmonGnRH ,[Trp7Leu8]GnRH)cDNAs ,即cDNA1和cDNA2 ,其长度分别为 393和 4 78bp。两个cDNAs都包括一个 2 85bp开放阅读框 ,编码的sGnRH前体为 94个氨基酸残基 ,由一个信号肽、sGnRH十肽和一个由蛋白水解位点 (Gly Lys Arg)连接的促性腺激素释放激素相关肽共 3部分组成。用内含子捕获得到相应的两个差异sGnRH基因 ,即sGnRHgene1和 gene2 ,其基本结构

Relevância:

10.00% 10.00%

Publicador:

Resumo:

M.8641是从武汉东湖分离培养的一株有毒的铜绿微囊藻(Microcystis aeruginosa),它产生两种环状短肽肝毒素。经凝胶过滤及HPLC等过程纯化,Waters Pico Tag系统测定,其主毒素(毒素Ⅰ)的氨基酸组成为:Glu(1),β-Masp(1),Ala(Ⅰ),Arg(2),Mdha(1),FAB-MS和MS/MS测定分子量为m/z1038,元素组成为C_(49)H_(76)O_(12)N_(13)。毒素Ⅱ的氨基酸组成,除一分子Arg为Leu取代外,其余与毒素Ⅰ相同,分子量m/z 9

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this study, an IL-8 homologue has been cloned and identified from a reptile, Chinese soft-shelled turtle for the first time. The full-length cDNA of turtle IL-8 was 1188 bp and contained a 312 bp open reading frame (ORF) coding for a protein of 104 amino acids. The chemokine CXC domain, which contained Glu-Leu-Arg (ELR) motif and four cysteine residues, was well conserved in turtle IL-8. The 4924 bp genomic DNA of turtle IL-8 contained four exons and three introns. Phylogenetic analysis showed that the amino acid sequence of turtle IL-8 clustered together with birds. RT-PCR analysis showed that turtle IL-8 mRNA was constitutively expressed liver, spleen, kidney, heart, blood and intestine tissues of control turtles. Real-time quantitative PCR analysis further indicated that the turtle IL-8 mRNA expression was apparent in various tissues at 8 h and up-regulated significantly during 8 h-7 d after Aeromonas hydrophila infection. The present studies will help us to understand the evolution of IL-8 molecule and the inflammatory response mechanism in reptiles. (C) 2009 Elsevier Ltd. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Gonadotropin-releasing hormone (GnRH) is a conservative neurodecapeptide family, which plays a crucial role in regulating the gonad development and in controlling the final sexual maturation in vertebrate. Two differing cGnRH-II cDNAs of common carp, namely cGnRH-II cDNA1 and cDNA2, were firstly cloned from the brain by rapid amplification of cDNA end (RACE) and reverse transcription- polymerase chain reaction (RT-PCR). The length of cGnRH-II cDNA1 and cDNA2 was 622 and 578 base pairs (bp), respectively. The cGnRH-II precursors encoded by two cDNAs consisted of 86 amino acids, including a signal peptide, cGnRH-II decapeptide and a GnRH-associated peptide (GAP) linked by a Gly-Lys-Arg proteolytic site. The results of intron trapping and Southern blot showed that two differing cGnRH-II genes in common carp genome were further identified, and that two genes might exist as a single copy. The multi-gene coding of common carp cGnRH-II gene offered novel evidence for gene duplication hypothesis. Using semi-quantitative RT-PCR, expression and relative expression levels of cGnRH-II genes were detected in five dissected brain regions, pituitary and gonad of common carp. With the exception of no mRNA2 in ovary, two cGnRH-II genes could be expressed in all the detected tissues. However, expression levels showed an apparent difference in different brain regions, pituitary and gonad. According to the expression characterization of cGnRH-II genes in brain areas, it was presumed that cGnRH-II might mainly work as the neurotransmitter and neuromodulator and also operate in the regulation for the GnRH releasing. Then, the expression of cGnRH-II genes in pituitary and gonad suggested that cGnRH-II might act as the autocrine or paracrine regulator.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

本工作设计并建立了一个离子-原子碰撞实验终端。该终端具有一定的通用性,可用于我所EcRIS、ECRIS一300kV高压平台和兰州大学Zxl.7MV串列加速器。终端的设计特别考虑了气体靶实验中系统的动态真空和对高品质弱束流流强的控制。2004年7月-10月,利用我所ECRIS提供的束流,在该终端上进行了首轮实验。本工作指出,除了入射离子的电荷态和速度外,其空能级结构是碰撞反应的另一个主导因素,并在此基础上提出了等电荷态序列离子的概念。为了确定离子空能级结构对碰撞反应的影响,本工作系统研究了等速度的q=6序列离子(C6+、N6+、。6+、F6+、Ne6+、Ar6+、co6+)、q=7序列离子(07+、F7+、Ne7+、57+、Ar7+)、q=8序列离子(FS+、Nes+、Ars+、cos+)、q:9序列离子(Fg+、Neg+、519+、59+、Arg+、cag+)和叮:11序列离子(Si1、Aill+、Call+)与氦、氖、氢的碰撞反应。实验证实,对于等速度、等电荷态序列离子,碰撞反应与离子种类强烈相关。利用同位素纯的13coZ作为EcRIs的工作气体,获得了纯净的全裸离子13C6+束流,研究了13C6+离子与氦、氖、氢碰撞反应与碰撞速度的关系。实验发现,在C6十一He的碰撞反应中,纯双电子俘获(DC)与双电子转移(DE)截面比JDcDIZ随碰撞速度的增加而明显下降,这暗示准分子俄歇机制在本能区C6+一He碰撞反应中的贡献不可忽略。用MCBM描述离子-原子相互作用阶段,用电子蒸发模型统一处理碰撞后多电了激发态散射离子和反冲离子的衰变,作者编写了计算程序COBEEM。经典过垒模型(如ECBM和MCBM)仅用电荷态q一个参数描述入射离子,本工作实验证实了这种描述是不完备的。COBEEM程序对此问题进行了初步修正。该程序还包含了ECBM和Selberg等人提出了经验公式的计算。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This article deals with (1) synthesis of novel cyclic carbonate monomer (2-oxo [1,3]dioxan-5-yl)carbamic acid benzyl ester (CAB) containing protected amino groups; (2) ring-opening copolymerization of the cyclic monomer with L-lactide (LA) to provide novel degradable poly(ester-carbonate)s with functional groups; (3) removal of the protective benzyloxycarbonyl (Cbz) groups by catalytic hydrogenation to afford the corresponding poly(ester-co-carbonate)s with free amino groups; (4) grafting of oligopeptide Gly-Arg-Gly-Asp-Ser-Tyr (GRGDSY, abbreviated as RGD) onto the copolymer pendant amino groups in the presence of 1,1'-carbonyldiimidazole (CDI).