Evolution of different oligorneric glycyl-tRNA synthetases

There are two oligomeric types of glycyl-tRNA synthetases (GlyRSs) in genome, the alpha(2)beta(2) tetramer and alpha(2) dimer. Here, we showed that the anticodon-binding domains (ABDs) of dimeric and tetrameric GlyRSs are non-homologous, although their catalytic central domains (CCDs) are homologous. The dimeric GlyRS_ABD is fused to the C-terminal of CCD in alpha-subunit, but the tetrameric GlyRS_ABD is to the C-terminal in beta-subunit during evolution. Generally, one species only contains one oligomeric type of GlyRS, but the both oligomeric GlyRSs with the multiple homologous domains can be observed in Magnetospirillum magnetotacticum genome, nevertheless, these homologous domains are probably from different genomes. (C) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

A de novo originated gene depresses budding yeast mating pathway and is repressed by the protein encoded by its antisense strand

Recent transcription profiling studies have revealed an unexpectedly large proportion of antisense transcripts in eukaryotic genomes. These antisense genes seem to regulate gene expression by interacting with sense genes. Previous studies have focused on the non-coding antisense genes, but the possible regulatory role of the antisense protein is poorly understood. In this study, we found that a protein encoded by the antisense gene ADF1 acts as a transcription suppressor, regulating the expression of sense gene MDF1 in Saccharomyces cerevisiae. Based on the evolutionary, genetic, cytological and biochemical evidence, we show that the protein-coding sense gene MDF1 most likely originated de novo from a previously non-coding sequence and can significantly suppress the mating efficiency of baker's yeast in rich medium by binding MAT alpha 2 and thus promote vegetative growth. These results shed new light on several important issues, including a new sense-antisense interaction mechanism, the de novo origination of a functional gene, and the regulation of yeast mating pathway.

The three dimensional structure and biological domains of the p53 C-terminus.

It was expected that there are a coil (289 similar to 325) and two a helix (alpha(1)368 similar to 373, alpha(2)381 similar to 388) structures in p53 protein C-terminal region based on its mRNA secondary structure template and Chou-Fasman's protein secondary structure principle of prediction. The result was conformed by the other four methods of protein secondary structure prediction that are based on the multiple sequence alignment (accuracy = 73.20%). Combine with the 31 amino acids crystal structure of the oligomerization, the three dimensional conformation of p53 C-terminal 108 residues was built using the SGI INDIGO(2) computer. This structure further expounds the relationship among those biological function domains of p53 C- terminus at three-dimensional level.

Extract of Ginkgo biloba leaves reverses yohimbine-induced spatial working memory deficit in rats

Extract of Ginkgo biloba is used to alleviate age-related decline in cognitive function, which may be associated with the loss of catecholamines in the prefrontal cortex. The purpose of this study was to verify whether alpha-2 adrenergic activity is involved in the facilitative effects of extract of Ginkgo biloba on prefrontal cognitive function. Male Wistar rats were trained to reach criterion in the delayed alternation task (0, 25, and 50-s delay intervals). A pilot study found that 3 or 4 mg/kg of yohimbine (intraperitoneal) reduced the choice accuracy of the delayed alternation task in a dose and delay-dependent manner, without influencing motor ability or perseverative behaviour. Acute oral pre-treatment with doses of 50, 100, or 200 mg/kg (but not 25 mg/kg) of extract of Ginkgo biloba prevented the reduction in choice accuracy induced by 4 mg/kg yohimbine. These data suggest that the prefrontal cognition-enhancing effects of extract of Ginkgo biloba are related to its actions on alpha-2-adrenoceptors.

鲫鱼蛋白激酶PKR-like的Zα结构域与聚肌胞苷酸的结合

根据鲫鱼类PKR蛋白激酶基因(CaPKR-like)的全长cDNA序列,克隆CaPKR-likeZα结构域cDNA(Zα1、Zα2和Zα1Zα2),原核表达成功获得3种融合蛋白PZα1、PZα2和PZα1Zα2。凝胶阻滞实验结果显示:PZα1、PZα2、PZα1和PZα2混合表达蛋白不能与聚肌胞苷酸(PolyI∶C)结合,而表达完整的Zα结构域的PZα1Zα2与PolyI∶C有明显的结合现象。另外,3种表达多肽PZα1、PZα2和PZα1Zα2在体外分别都能聚合形成二聚体。与PZα1相比,PZα2和PZα

雌核发育银鲫和两性融合彩鲫卵母细胞体外诱导成熟过程中周期蛋白合成和MPF活性变化的比较研究

采用体外诱导卵母细胞成熟技术 ,比较研究了雌核发育银鲫和两性融合发育彩鲫卵母细胞成熟过程中周期蛋白合成和MPF活性变化情况。结果表明 :1 7α ,2 0 β 二氢孕酮(简称DP)浓度为 0 5μg/ml,温度为 2 4℃ ,光照时间 2 0小时为最适诱导条件。在相同条件下 ,两性生殖彩鲫卵母细胞体外诱导成熟速度明显快于银鲫。相应的细胞学研究表明 ,在体外诱导时 ,银鲫和彩鲫卵母细胞的发育成熟是正常的。银鲫卵母细胞生发泡破裂 (GVBD)时已有周期蛋白的合成 ,但生发泡破裂开始后则呈现合成速度下降直至没有

唾液酸转移酶Ⅰ（ST6GalⅠ）及甲胎蛋白（AFP）上肝癌特异糖链在肝细胞肝癌细胞系和肝病患者血液中的表达

肝癌（HCC）是一种重要的恶性肿瘤，具有高发病率和不良预后的特点，在中国有很多的肝癌患者。早期发现和精确区分肝癌与其他肝病，对于肝癌的临床诊断治疗有十分重要的作用。由于肝脏所处位置较深，以及检测仪器和手段的限制，肝癌的早期诊断相对困难，所以比较好的血清学标记物应用于早期区分肝癌和其他肝病显得尤为重要。目前应用较多的标记物是甲胎蛋白AFP。由于单独的AFP其敏感性和特异性并不高，更为理想的检测手段正在研究中。 Beta-galactoside alpha-2,6-sialyltransferase Ⅰ(ST6GalⅠ)是唾液酸转移酶家族中的一员，主要调控蛋白的唾液酸化。有研究发现ST6Gal在肝癌中表达升高，而且随着肝实体瘤的恶化而可能被释放到外周血中。所以血液中的ST6GalⅠ水平可能是一种有潜力的肝癌指标。另外，有研究显示，AFP的糖链结构在肝癌和其他肝病中是不同的，如果能用AFP上肝癌特异糖链作为检测目标，联合已有的检测体系，可能有助于早期精确诊断肝癌。 目的：我们选择ST6Gal Ⅰ和AFP上肝癌特异糖链TF（Thomsen-Friedenreich）抗原，H2血型抗原，Lewis Y血型抗原作为主要的研究内容，通过对其在肝癌细胞系和肝病血液中的表达研究，探讨其应用于肝癌早期诊断的可能。 方法：1）用合成的ST6Gal Ⅰ多肽免疫兔子，制备抗ST6Gal Ⅰ多克隆抗体；2）通过免疫细胞化学，ELISA和western blot等方法对制作的兔多克隆抗体进行效价分析；3）通过western blot方法对肝癌、肝硬化和正常人的血浆和血清中ST6Gal表达进行研究；4）通过免疫沉淀的方法对肝癌细胞系和肝癌血浆中AFP上肝癌特异糖链进行研究。 结果：1）制备的兔抗人ST多克隆抗血清，效价可达1:400000，能够通过 免疫细胞化学和western blot检测到肝癌细胞系中的ST6GalⅠ；2）所选的3例肝癌血浆和2例肝癌血清中都有ST6GalⅠ阳性，在所选的2例肝硬化血浆和2例肝硬化血清中，分别只有1例有ST6GalⅠ的阳性，在3例正常人血浆中有2例有ST6GalⅠ阳性；3）AFP上肝癌特异的糖链TF抗原、H2抗原、Lewis Y抗原可以通过免疫沉淀的方法在肝癌病人血浆和肝癌细胞系HepG2中检出。 结论：制备的兔抗人ST6GalⅠ多克隆抗体具有较高效价，并可以检测到自然状态和变性状态的目标蛋白，可以应用于ST6GalⅠ的研究；通过western blotting对肝病血液的检测，发现在肝癌、肝硬化和正常人血液中的ST6GalⅠ的表达有差异，为ST6GalⅠ作为一种肿瘤标记物进行血清学检测提供了可能的前提；免疫沉淀的结果，证实了在肝癌病人的AFP上有TF、H2、LewisY等糖链的存在，为AFP上肝癌特异糖链作一种区分肝癌和其他良性肝病的标记物提供了证据。

唾液酸转移酶Ⅰ（ST6GalⅠ）及甲胎蛋白（AFP）上肝癌特异糖链在肝细胞肝癌细胞系和肝病患者血液中的表达

肝癌（HCC）是一种重要的恶性肿瘤，具有高发病率和不良预后的特点，在中国有很多的肝癌患者。早期发现和精确区分肝癌与其他肝病，对于肝癌的临床诊断治疗有十分重要的作用。由于肝脏所处位置较深，以及检测仪器和手段的限制，肝癌的早期诊断相对困难，所以比较好的血清学标记物应用于早期区分肝癌和其他肝病显得尤为重要。目前应用较多的标记物是甲胎蛋白AFP。由于单独的AFP其敏感性和特异性并不高，更为理想的检测手段正在研究中。 Beta-galactoside alpha-2,6-sialyltransferase Ⅰ(ST6GalⅠ)是唾液酸转移酶家族中的一员，主要调控蛋白的唾液酸化。有研究发现ST6Gal在肝癌中表达升高，而且随着肝实体瘤的恶化而可能被释放到外周血中。所以血液中的ST6GalⅠ水平可能是一种有潜力的肝癌指标。另外，有研究显示，AFP的糖链结构在肝癌和其他肝病中是不同的，如果能用AFP上肝癌特异糖链作为检测目标，联合已有的检测体系，可能有助于早期精确诊断肝癌。 目的：我们选择ST6Gal Ⅰ和AFP上肝癌特异糖链TF（Thomsen-Friedenreich）抗原，H2血型抗原，Lewis Y血型抗原作为主要的研究内容，通过对其在肝癌细胞系和肝病血液中的表达研究，探讨其应用于肝癌早期诊断的可能。 方法：1）用合成的ST6Gal Ⅰ多肽免疫兔子，制备抗ST6Gal Ⅰ多克隆抗体；2）通过免疫细胞化学，ELISA和western blot等方法对制作的兔多克隆抗体进行效价分析；3）通过western blot方法对肝癌、肝硬化和正常人的血浆和血清中ST6Gal表达进行研究；4）通过免疫沉淀的方法对肝癌细胞系和肝癌血浆中AFP上肝癌特异糖链进行研究。 结果：1）制备的兔抗人ST多克隆抗血清，效价可达1:400000，能够通过免疫细胞化学和western blot检测到肝癌细胞系中的ST6GalⅠ；2）所选的3例肝癌血浆和2例肝癌血清中都有ST6GalⅠ阳性，在所选的2例肝硬化血浆和2例肝硬化血清中，分别只有1例有ST6GalⅠ的阳性，在3例正常人血浆中有2例有ST6GalⅠ阳性；3）AFP上肝癌特异的糖链TF抗原、H2抗原、Lewis Y抗原可以通过免疫沉淀的方法在肝癌病人血浆和肝癌细胞系HepG2中检出。 结论：制备的兔抗人ST6GalⅠ多克隆抗体具有较高效价，并可以检测到自然状态和变性状态的目标蛋白，可以应用于ST6GalⅠ的研究；通过western blotting对肝病血液的检测，发现在肝癌、肝硬化和正常人血液中的ST6GalⅠ的表达有差异，为ST6GalⅠ作为一种肿瘤标记物进行血清学检测提供了可能的前提；免疫沉淀的结果，证实了在肝癌病人的AFP上有TF、H2、LewisY等糖链的存在，为AFP上肝癌特异糖链作一种区分肝癌和其他良性肝病的标记物提供了证据。

In situ UV-vis and CD thin-layer spectroelectrochemistry study of the electrochemical behavior of L-noradrenaline in alkaline solution

Electrochemical redox behavior of noradrenaline in alkaline solution on a glassy carbon electrode has been investigated by in situ UV-vis and CD spectroelectrochemistry by using a long optical path thin-layer cell. The experimental data were processed by using a double logarithmic method of analysis together with nonlinear regression which confirmed that the first step in both the oxidation of noradrenaline and reduction of noradrenochrome is a two-electron irreversible process governed by an EE mechanism. The kinetic parameters of the electrode reactions, i.e., charge transfer coefficient and the number of electrons transferred, alpha(1)n(1) = 0.11 and alpha(2)n(2) = 0.23, formal potentials modified with kinetics, E-1(0') = 0.65 (+/- 0.01) V and E-2(0') = 0.72V and standard rate cnstants, k(1)(0) = 7.0(+/-0.5)x10(-5) cm s(-1), for the first and second steps in the oxidation process of noradrenaline, and similarly, alpha(1)n(1) = 0.33, alpha(2)n(2) = 0.58, E-1(0') = 0.37(+/-0.01) V, E-0' = -0.25 (+/-0.01) V and k(1)(0) approximate to k(2)(0) = 1.06 (+/-0.05)x10(-4) cm s(-1) for the first and second steps in the reduction process of noradrenochrome were also determined.

SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF THE DAWSON-TYPE TUNGSTOPHOSPHATE HETEROPOLY COMPLEXES SUBSTITUTED BY NIOBIUM

Eight new complexes alpha(2)-M(7-m)H(m)[P2W17NbO62]. H2O and alpha-1, 2, 3-M(g-m)H(m) [P2W15Nb3O62]. XH(2)O(M=K, TMA, TEA, TBA) were synthesized and characterized by IR and UV spectroscopy, polarography, XPS and XRD methods. P-31 and W-183 NMR studies show that the niobium atoms in the anions are on the polar sites. The crystal of alpha-1, 2, 3-K7H2 [P2W15Nb3O62]. 30H(2)O is hexagonal, its cell parameters: a=1.9836(4), b=1.9836(9), c=1.5498(6)nm, alpha=beta=90 degrees, gamma=120 degrees.

Influence of carbon on the thermoluminescence and optically stimulated luminescence of α -Al2O3:C crystals

alpha-Al2O3:C crystal shows excellent thermoluminescence (TL) and optically stimulated luminescence (OSL) properties but the real role carbon plays in this crystal is still not clearly understood so far. In this work, alpha-Al2O3:C crystal doping with different amounts of carbon were grown by the temperature gradient technique, and TL and OSL properties of as-grown crystals were investigated. Additionally, a mechanism was proposed to explain the role of carbon in forming the TL and OSL properties of alpha-Al2O3:C. TL and OSL intensities of as-grown crystals increase with the increasing amount of carbon doping in the crystal, but no shift is found in the glow peak location at 465 K. As the amount of carbon doping in the crystals decreases, OSL decay rate becomes faster. With the increase in heating rate, the integral TL response of as-grown crystals decreases and glow peak shifts to higher temperatures. TL response decrease rate increases with the increasing amount of carbon doping in the crystals. All the TL and OSL response curves of as-grown crystals show linear-sublinear-saturation characteristic, and OSL dose response exhibits higher sensitivity and wider linear dose range than that of TL. The crystal doping with 5000 ppm carbon shows the best dosimetric properties. Carbon plays the role of a dopant in alpha-Al2O3:C crystal and four-valent carbon anions replace the two-valent anions of oxygen during the crystal growth process, and large amounts of oxygen vacancies were formed, which corresponds to the high absorption coefficient of F and F+ centers in the crystals.

奶牛胚胎移植中GnRH、PGF_(2)#alpha#同期发情处理效果的比较

193头健康、经产的黑白花奶牛分为3个组,用3种不同的方法进行同期发情处理和胚胎移植。第1组:注射1次Lutalyse;第2组:注射2次Lutalyse;第3组:注射Fertagyl-Lutalyse-Fertagyl。结果表明:第1组和第2组之间的同期发情胚胎移植率无显著差异(P>0.05),分别为26.5%(21/79)和27.0%(18/68);第3组的同期发情胚胎移植率为60.9%(28/46),显著高于第1组和第2组(P<0.05)。

Molecular cloning and stress-induced expression of paralichthys olivaceus heme-regulated initiation factor 2 alpha kinase

The heme-regulated initiation factor 2 alpha kinase (HRI) is acknowledged to play an important role in translational shutoff in reticulocytes in response to various cellular stresses. In this study, we report its homologous cDNA cloning and characterization from cultured flounder embryonic cells (FEC) after treatment with UV-inactivated grass carp haemorrhagic virus (GCHV). The full-length cDNA of Paralichthys olivaceus HRI homologue (PoHRI) has 2391 bp and encodes a protein of 651 amino acids. The putative PoHRI protein exhibits high identity with all members of eIF2 alpha kinase family. It contains 12 catalytic subdomains located within the C-terminus of all Ser/Thr protein kinases, a unique kinase insertion of 136 amino acids between subdomains IV and V, and a relatively conserved N-terminal domain (NTD). Upon heat shock, virus infection or Poly PC treatment, PoHRI mRNA and protein are significantly upregulated in FEC cells but show different expression patterns in response to different stresses. In healthy flounders, PoHRI displays a wide tissue distribution at both the mRNA and protein levels. These results indicate that PoHRI is a ubiquitous eIF2a kinase and might play an important role in translational control over nonheme producing FEC cells under different stresses. (c) 2006 Elsevier Ltd. All rights reserved.

Citrate-gel synthesis and luminescent properties of alpha-Zn-3(PO4)(2) doped with Eu3+

By using inorganic salts as raw materials and citric acid as complexing agent, alpha-Zn-3(PO4)(2) and Eu3+ doped alpha-Zn-3(PO4)(2) phosphor powders were prepared by a citrate-gel process. X-ray diffraction, (XRD), TG - DTA, FT - IR and luminescence excitation and emission spectra were used to characterize the resulting products. The results of XRD reveal that the powders begin to crystallize at 500 degreesC and pure alpha-Zn-3(PO4)(2) phase is obtained at 800 degreesC. And the results of XRD reveal that Eu3+ exists Lis EoPO(4) ill the powder. In the phosphor powders, the Eu3+ shows its characteristic red-orange (592 nm, D-5(0) - F-7(1)) emission and has no quenching concentration.

Investigation of the effect of branched structure on the performances of the copolymers synthesized from ethylene and alpha-olefin with rac-Et(Ind)(2)ZrCl2/MMAO catalyst system

The branched copolymers prepared from ethylene and alpha-olefins using rac-Et(Ind)(2)ZrCl2/MMAO catalyst system were studied. Both the absolute molecular weight ((M) over bar (W)) and the molecular size (radius of glyration, R-g) of the polymers eluting from gel permeation chromatography (GPC) columns were obtained simultaneously via a high temperature GPC coupled with a two-angle laser light scattering (TALLS) detector. The branched structures and performances of the copolymers display approximate molecular weight and molecular sizes were investigated. Wide angle X-ray diffraction analyses indicate that 16-carbon side branch could co-crystallize effectively with backbone chain at low alpha-olefin incorporation. The melt behaviors of the copolymers were studied by dynamic rheological measurements. Both branch length and comonomer content affect considerably the loss modulus, storage modulus and complex viscosity of the copolymers. The relationship between the dynamic-mechanical behavior and the comonomer content of the copolymers was also examined by dynamic-mechanical experiments.