CRBGP通过抑制FAK-AKT通路和白介素-6的分泌抑制胶质瘤U251细胞的活性

目的 电压门控钠通道(voltage-gated sodium channels,VGSCs)表达于胶质瘤U251细胞,并影响U251细胞的增殖、侵袭和凋亡.富含半胱氨酸的颊腺蛋白(cysteine-rich buccal gland protein,CRBGP)是一种从日本七鳃鳗颊腺中分离出来的VGSCs阻断剂.本文...     

18F-FDG PET和治疗量131I全身扫描对分化型甲状腺癌根治术后转移灶检测的临床价值评估

目的：探讨18F-FDG PET显像和131I-全身扫描（131I-WBS）SPECT显像对分化型甲状腺癌（DTC）术后转移灶的临床诊断价值。方法：对57例外科术后拟行131I治疗的DTC患者行18F-FDG PET全身显像和131I-WBS扫描,观察和记录在糖代谢和碘代谢中DTC转移灶的定位及数量变化,并同时测定甲状腺球蛋白（Tg）,促甲状腺激素释放激素（TSH）等实验室检查项目。结果：57例DTC患者18F-FDG PET显像发现真阳性20例、假阳性3例、真阴性31例、假阴性3例,其灵敏度为87.0%,特异性为91.2%。而131I-WBS扫描发现真阳性13例、假阳性2例、真阴性34例、假阴性8例,其灵敏度为61.9%,特异性为94.4%。PET显像和131I-WBS扫描共检出阳性病灶73个,其中淋巴结32个,肺5个,纵隔6个,骨26个,其他部位4个。PET显像发现43个阳性病灶（58.9%）,而131I-WBS检出30个（41.1%）。当Tg水平〉10μg/L时,随着Tg在血清含量的增高,两种显像方法的对DTC转移灶的阳性检出率亦随之升高。结论：两种检查对DTC术后转移灶的监测和131I的治疗具有良好的互补性,18F-FDG PET显像在Tg阳性和131I-WBS阴性的患者的转移灶检出上更具有优势,有重要的临床指导意义。     

猪CFL2b 基因cDNA克隆初步分析

利用基因表达谱芯片分析法筛选出与大白猪高肌肉产量-肌纤维形成有关的CFL2b基因.参考人和小鼠CFL2b基因序列,采用SMART-RACE技术结合EST序列拼接技术,从猪骨骼肌肌肉中首次克隆了猪CFL2b的全长cDNA序列（GenBank登录号EU561660,EU561661）,Northern杂交检测CFL2b基因 mRNA.结果表明,猪CFL2b基因含有2个转录本,长转录本3　012 bp,短转录本1　466 bp .CFL2b基因在多种真核生物中都有表达,且编码区序列非常保守,开放式读码框501 bp编码了166个氨基酸的蛋白质.氨基酸序列分析表明,猪CFL2基因与人和小鼠氨基酸同源性分别为100%和99.1%.核苷酸序列相似性分别为88.1%和74.9%.     

Cloning of a gluconate/polyol dehydrogenase gene from <Emphasis Type="Italic">Gluconobacter suboxydans</Emphasis> IFO 12528, characterisation of the enzyme and its use for the production of 5-ketogluconate in a recombinant <Emphasis Type="Italic">Escherichia coli</Emphasis> strain

A 5-ketogluconate (5-KGA)-forming membrane quinoprotein, gluconate dehydrogenase, was isolated from Gluconobacter suboxydans strain IFO 12528 and partially sequenced. Partial sequences of five internal tryptic peptides were elucidated by mass spectrometry and used to isolate the two adjacent genes encoding the enzyme (EBI accession no. AJ577472). These genes share close homology with sorbitol dehydrogenase from another strain of G. suboxydans (IFO 3255). Substrate specificity of gluconate 5-dehydrogenase (GA 5-DH) turned out to be quite broad, covering many polyols, amino derivatives of carbohydrates, and simple secondary alcohols. There is a broad correlation between the substrate specificity of GA 5-DH and the empirical Bertrand-Hudson rule that predicts the specificity of oxidation of polyols by acetic acid bacteria. Escherichia coli transformed with the genes encoding gluconate dehydrogenase were able to convert gluconic acid into 5-KGA at 75% yield. Furthermore, it was found that 5-KGA can be converted into tartaric acid semialdehyde by a transketolase. These results provide a basis for designing a direct fermentation-based process for conversion of glucose into tartaric acid.     

Anti-alpha-fodrin antibodies do not add much to the diagnosis of Sjögren's syndrome

The presence of anti-alpha-fodrin autoantibodies has been reported to be a highly specific and sensitive test for the diagnosis of Sj?gren's syndrome (SjS). We looked (in Nijmegen) for anti-alpha-fodrin, anti-Ro60, and anti-La autoantibodies in a cohort of 51 patients with rheumatic diseases (primary SjS [21], secondary SjS 6, rheumatoid arthritis [RA] 12, systemic lupus erythematosus [SLE] 6, and scleroderma 6) and in 28 healthy subjects, using ELISA, immunoblotting, and immunoprecipitation. The same samples were analyzed with an alternative anti-alpha-fodrin ELISA in Hanover. The Nijmegen ELISA of the sera from primary SjS showed sensitivities of 43% and 48% for IgA- and IgG-type anti-alpha-fodrin antibodies, respectively. The Hanover ELISA showed sensitivities of 38% and 10% for IgA- and IgG-type anti-alpha-fodrin antibodies, respectively. The ELISAs for alpha-fodrin showed six (Nijmegen) and four (Hanover) anti-alpha-fodrin-positive RA sera. IgA and IgG anti-fodrin antibodies were also present in four patients with secondary SjS. The sensitivities of Ro60 and La-antibodies in the Nijmegen ELISA were 67% and 62%, respectively. Unlike anti-alpha-fodrin antibodies, all anti-Ro60 and anti-La positive sera could be confirmed by immunoblotting or RNA immunoprecipitation. Thus, anti-Ro and anti-La autoantibodies were more sensitive than anti-alpha-fodrin autoantibodies in ELISA and were more frequently confirmed by other techniques. Anti-La antibodies appear to be more disease-specific than anti-alpha-fodrin antibodies, which are also found in RA sera. Therefore, the measurement of anti-alpha-fodrin autoantibodies does not add much to the diagnosis of Sj?gren's syndrome.     

Structural insights into the beta-xylosidase from Trichoderma reesei obtained by synchrotron small-angle X-ray scattering and circular dichroism spectroscopy

The enzyme beta-xylosidase from Trichoderma reesei, a member of glycosil hydrolase family 3 (GH3), is a glycoside hydrolase which acts at the glycosidic linkages of 1,4-beta-xylooligosaccharides and that also exhibits alpha-l-arabinofuranosidase activity on 4-nitrophenyl alpha-l-arabinofuranoside. In this work, we show that the enzyme forms monomers in solution and derive the low-resolution molecular envelope of the beta-xylosidase from small-angle X-ray scattering (SAXS) data using the ab initio simulated annealing algorithm. The radius of gyration and the maximum dimension of the beta-xylosidase are 30.3 +/- 0.2 and 90 +/- 5 A, respectively. In contrast to the fold of the only two structurally characterized members of GH3, the barley beta-d-glucan exohydrolase and beta-hexosaminidase from Vibrio cholerae, which have respectively two or one distinct domains, the shape of the beta-xylosidase indicates the presence of three distinct structural modules. Domain recognition algorithms were used to show that the C-terminal part of the amino acid sequence of the protein forms the third domain. Circular dichroism spectroscopy and secondary structure prediction programs demonstrate that this additional domain adopts a predominantly beta conformation.     

1-O-Acetyl-beta-D-galactopyranose: a novel substrate for the transglycosylation reaction catalyzed by the beta-galactosidase from Penicillium sp

1-O-Acetyl-beta-D-galactopyranose (AcGal), a new substrate for beta-galactosidase, was synthesized in a stereoselective manner by the trichloroacetimidate procedure. Kinetic parameters (K(M) and k(cat)) for the hydrolysis of 1-O-acetyl-beta-D-galactopyranose catalyzed by the beta-D-galactosidase from Penicillium sp. were compared with similar characteristics for a number of natural and synthetic substrates. The value for k(cat) in the hydrolysis of AcGal was three orders of magnitude greater than for other known substrates. The beta-galactosidase hydrolyzes AcGal with retention of anomeric configuration. The transglycosylation activity of the beta-D-galactosidase in the reaction of AcGal and methyl beta-D-galactopyranoside (1) as substrates was investigated by 1H NMR spectroscopy and HPLC techniques. The transglycosylation product using AcGal as a substrate was beta-D-galactopyranosyl-(1-->6)-1-O-acetyl-beta-D-galactopyranose (with a yield of approximately 70%). In the case of 1 as a substrate, the main transglycosylation product was methyl beta-D-galactopyranosyl-(1-->6)-beta-D-galactopyranoside. Methyl beta-D-galactopyranosyl-(1-->3)-beta-D-galactopyranoside was found to be minor product in the latter reaction.     

Melon rugose mosaic virus, the cause of a disease of watermelon and sweet melon

A mechanically transmissible virus with isometric particles c. 32 nm in diameter, was isolated from infected watermelons and sweet melons in the People's Democratic Republic of Yemen. Purified virus preparations contained two major sedimenting components with sedimentation coefficients of 61S and 117S. In isopycn ic centrifugation in CsCl the particles formed a single band of buoyant density 1.39 g cm^-3. Preparations of virus particles comprised of a single polypeptide of mol. wt c. 22 000 and ssRNA of mol. wt 2.1 × 10⁶. The virus was serologically related to three of six subgroups of tymoviruses tested. The name melon rugose mosaic virus is proposed for this newly described virus.     

Isolation, enzymatic properties, and mode of action of an exo-1,3-beta-glucanase from Trichoderma viride.

An exo-1,3-beta-glucanase has been isolated from cultural filtrate of T. viride AZ36. The N-terminal sequence of the purified enzyme (m = 61 +/- 1 kDa) showed no significant homology to other known glucanases. The 1,3-beta-glucanase displayed high activity against laminarins, curdlan, and 1,3-beta-oligoglucosides, but acted slowly on 1,3-1,4-beta-oligoglucosides. No significant activity was detected against high molecular mass 1,3-1,4-beta-glucans. The enzyme carried out hydrolysis with inversion of the anomeric configuration. Whereas only glucose was released from the nonreducing terminus during hydrolysis of 1,3-beta-oligoglucosides, transient accumulation of gentiobiose was observed during hydrolysis of laminarins. The gentiobiose was subsequently degraded to glucose. The Michaelis constants Km and Vmax have been determined for the hydrolysis of 1,3-beta-oligoglucosides with degrees of polymerization ranging from 2 to 6. Based on these data, binding affinities for subsites were calculated. Substrate binding site contained at least five binding sites for sugar residues.