Terreinol--a novel metabolite from Aspergillus terreus: structure and C labeling

A novel metabolite from Aspergillus terreus, named terreinol, was isolated and its biosynthetic origin was determined by NMR based on the incorporation of [1-¹³C]-d-glucose. The labeling pattern indicated a predominant polyketide biosynthetic origin for this metabolite.     

生物材料中克伦特罗的气相色谱-质谱法测定

建立了生物材料中克伦特罗 (clenbuterol)的气相色谱 -质谱测定方法 ;大白鼠喂食克伦特罗获得阳性生物材料 ,生物材料中克伦特罗经0.01mol/L盐酸溶液提取 ,乙醚脱脂净化 ,乙酸乙酯提取后蒸发至干 ,用乙醇溶解后加样到氧化铝柱上 ,用0.01mol/L盐酸溶液洗脱 ,蒸发至干后 ,用BSTFA(双三甲基硅烷基三氟乙酰胺 ) +1 % (φ)TMCS(三甲基氯硅烷 )衍生 ,采用GC -MS进行测定 ,外标法定量 ;试验表明 ,生物材料中添加0.056×10 -6～0.54×10 -6(w)含量水平的克伦特罗 ,方法回收率在89 %～107 % ,相对标准偏差为7.3 %～16 % ,线性相关系数r为0.998,克伦特罗的检出限为2.0×10-9(w)。     

Photodynamic therapy based on organic small molecular fluorescent dyes

This review aims to provide a summary of the progress in organic small molecular fluorescent dyes for photodynamic therapy in recent years and it is classified according to the structures of dyes including cyanines, phthalocyanine, BODIPYs and other agents.     

赖氨酸-Ag反应机理的研究

The interaction of silver(Ⅰ) ion with lysine has been investigated by UV-Vis, fluorescent spectra and electrophoresis method. The effect of pH medium and multicomponent concentration on interaction of lysine-silver has also been studied. Lysine-silver system showed maximum absorbance at 239 nm and 448 nm. Lysine showed fluorescence. The fluorescence excitation wavelength was about 356.6 nm (fluorescence emission wavelength was about 438.6 nm). When the reaction of silver(Ⅰ) ion with lysine happened, fluorescence was quenching. Lysine-silver system carried negative charge, and the electrokinetic potential of double electrode layer was -2.35×10^-4 V.     

Cross-linking chemistry and biology: development of multifunctional photoaffinity probes

An efficient method of photoaffinity labeling has been developed based on rationally designed multifunctional photoprobes. Photoaffinity techniques have been used to elucidate the protein structure at the interface of biomolecules by the photochemical labeling of interacting sites. However, the identification of labeled sites within target proteins is often difficult. Novel biotinyl bioprobes bearing a diazirine photophore have contributed significantly to the rapid elucidation of ligand binding sites within proteins, thereby extending conventional photoaffinity methods. This article discusses the synthesis and applications of various photoprobes bearing a biotin, including strategies using cleavable linkages between photophores. The combination of photoaffinity methods with chip technology is also described as a novel entry to rapid affinity-based screening of inhibitors. This review focuses on a rapid and reliable photoaffinity method utilizing diazirine-based multifunctional photoprobes with numerous potential applications in functional proteomics of biomolecular interactions.     

Resonance Rayleigh scattering determination of trace amounts of Al in natural waters and biological samples based on the formation of an Al(III)-morin-surfactant complex

A novel method for the determination of trace amounts of Al(III) based on resonance Rayleigh scattering (RRS) has been developed. In the presence of some surfactants, Al(III) can react with morin and form an Al(III)-morin-surfactant complex, which results in the enhancement of RRS intensity and the appearance of the corresponding RRS spectral characteristics. Their maximum scatter peaks are at 476 nm for the cetyltrimethylammonium bromide (CTAB) system, 489 nm for the cetylpyridinium chloride (CPC) system, 474 nm for the Triton X-100 system, and 473 nm for the Tween-20 system. The enhanced RRS intensity is directly proportional to the concentration of Al(III). The detection limits are in the range of (0.50-1.2)×10⁻⁷ mol l⁻¹ depending on the surfactant. The characteristics of RRS spectra of the complexes, the optimum conditions of these reactions and the influencing factors have been investigated. The method has high selectivity, and was successfully applied to the determination of Al(III) in natural and biological samples. Furthermore, according to different complexation capacity of Al(III)-morin-CTAB system under two pH conditions, speciation analysis of Al(III) in natural waters was explored. The labile monomeric Al fraction (mainly inorganic Al, Al_i) is determined at acidic pH and the total monomeric Al fraction (Al_a) is determined at alkaline pH. The results are in agreement with those obtained by Driscoll’s 8-hydroxyquinoline extraction-ion exchange method.     

Cp/mas 13c nmr and Electron Diffraction Study of Bacterial Cellulose Structure Affected by Cell Wall Polysaccharides

Acetobacter xylinum was cultured in Schramm–Hestrin medium containing pectin (pectin medium), xylan (xylan medium), or glucomannan (mannan medium). X-ray diffractometry revealed that xylan and glucomannan affected the size of the cellulose crystals and their d-spacing values. Solid-state cross polarization magic angle spinning carbon-13 nuclear magnetic resonance spectroscopy indicated that the ratio of cellulose I was reduced by the addition of polysaccharides. These effects were more remarkable on the cellulose in the mannan medium than that in the xylan medium, and were scarcely observed in the pectin medium. Electron diffraction analysis revealed that these effects on hemicelluloses along cellulose microfibrils are continuous in the mannan medium and discontinuous in the xylan medium. These findings suggest that the uronic acid in the polysaccharides prevents interactions with cellulose leading to alterations of the structure of the cellulose crystal.     

含硅二硫代磷酸酯的合成及生物活性

硅基甲硫醇Ｒ＾１Ｒ＾２ＣＨ３ＳｉＣＨ２ＳＨ与Ｏ，Ｏ－二烷基二硫代磷酸酯（ＲＯ）２Ｐ（Ｓ）ＳＨ及甲醛可顺利地发生类Ｍａｎｎｉｃｈ缩合反应，利用此反应和硅基甲硫醇与Ｏ，Ｏ－二乙基－Ｓ（２－溴乙基）二硫代磷酸酯的取代反应合成了３７种新的含硅二硫代到酯化合物（ＲＯ）２Ｐ（Ｓ）Ｓ（ＣＨ２）ｎＳＣＨ２ＳｉＣＨ３Ｒ＾１Ｒ＾２（ｎ＝１，２），在初筛浓度下，该类化合物具有一定的杀虫，杀螨活性。     

神经生长因子的化学发光标记与检测

以辣根过氧化物酶（ＨＲＰ）和吖啶酯（ＡＥ）为化学发光标记试剂分别标记神经生长因子（ＮＧＦ）单克隆抗体，经分离纯化制成标记抗体（ＨＲＰ－Ａｂ，ＡＥ－Ａｂ），采用化学发光免疫分析法（ＣＬＩＡ）对ＮＧＦ进行检测，其检出限为０．５ｎｇ／ｍＬ，线性范围为２～１２８ｎｇ／ｍＬ．１０例样本分别用ＣＬＩＡ和ＲＩＡ进行检测，其结果无显著性差异．     

X-射线荧光光谱法测定钛铁中的硅、锰、磷、铝

介绍用X-射线荧光光谱仪测定钛铁中Si、Mn、P、Al含量的方法,通过试验确定了合适的研磨时间、压力和保压时间,用压片法制样,建立了各元素的工作曲线,各元素的测定范围分别为Si3.00%～6.00%,Mn1.00%～3.00%,P0.030%～0.070%,Al5.00%～9.00%。通过强度测量得到测定Si、Mn、P、Al的相对标准偏差分别为0.074%、0.308%、0.383%、0.040%,精密度满足测试要求。将该方法测定结果与化学法比对,准确度满足国家标准方法分析误差的要求。