Detection of menadione sodium bisulfite (vitamin K-3) by reversed-phase high performance liquid chromatography with series dual-electrode amperometric detector

A reversed-phase high-performance liquid chromatography with series dual glassy carbon electrodes for the amperometric detection of water-soluble menadione is described. The complex post-column derivatization reaction and the high background currents were avoided. The menadione sodium bisulfite was reduced at -0.3 V vs. SCE at the upstream (generator) electrode and oxidized at +0.2V vs. SCE at the downstream (collector) electrode. The mobile phase was 0.2moll(-1) HAc-NaAc aqueous buffer (pH 5.50) and 40% (v/v) methanol. The linear response was in the range of 35 ng to 15 mu g, with a detection Limit of 15 ng (S/N=3). The correlation coefficient was 0.9997 (n=6). The electrochemical detection with series dual electrodes has a higher selectivity for menadione (vitamin K-3) compound than with UV detection.

~(14)C标记1,2,7,8-TCDD在鲤体内分布及代谢的初步研究

利用14C标记1,2,7,8-四氯代二苯并二噁英(1,2,7,8Tetrachloro[U—14C]dibenzodioxin,14C1,2,7,8TCDD)初步研究了其在鲤体内的分布和代谢规律。14C1,2,7,8-TCDD溶解于丙酮/植物油中,腹腔暴露。暴露1、2、4、8、12d后取样,肝脏、胆汁、腹腔脂肪等消化制样后用液闪仪测量放射性活度。肝脏和胆汁内的放射性活度同步变化,都是第8d达到峰值后下降。腹腔脂肪内1—2d放射性明显高于随后取样的样品。肝和腹腔脂肪的分布量之比呈现“S”型变化趋势。暴露4d

A self-consistent field theory study on the morphologies of linear ABCBA and H-shaped (AB)(2)C(BA)(2) block copolymers

By using a combinatorial screening method based on the self-consistent field theory, we investigate the equilibrium morphologies of linear ABCBA and H-shaped (AB)(2)C(BA)(2) block copolymers in two dimensions. The triangle phase diagrams of both block copolymers are constructed by systematically varying the volume fractions of blocks A, B, and C. In this study, the interaction energies between species A, B, and C are set to be equal. Four different equilibrium morphologies are identified, i.e., the lamellar phase (LAM), the hexagonal lattice phase (HEX), the core-shell hexagonal lattice phase (CSH), and the two interpenetrating tetragonal lattice phase (TET2). For the linear ABCBA block copolymer, the reflection symmetry is observed in the phase diagram except for some special grid points, and most of grid points are occupied by LAM morphology. However, for the H-shaped (AB)(2)C(BA)(2) block copolymer, most of the grid points in the triangle phase diagram are occupied by CSH morphology, which is ascribed to the different chain architectures of the two block copolymers. These results may help in the design of block copolymers with different microstructures.

DEHYDROGENATION OF ORGANOLANTHANIDE ALKOXIDES AND X-RAY CRYSTAL-STRUCTURE OF REACTION-PRODUCT [(C5H-5)2YB(MU-OCH=C=CH2)]2

[Cp3Yb] reacts with HOR (Cp = C5H5; R = CH2CH=CH2, CH2CH2Me) in thf (thf = tetrahydrofuran)at room temperature to give complexes [{Cp2Yb(mu-OR)}2], which are dehydrogenated to yield the new complex [{Cp2Yb(mu-OCH=C=CH2)}2] in refluxing thf solution; the X-ray crystal structure shows that the new complex is dimeric with oxygen atoms as bridging groups.

固体~(13)C NMR研究呋喃醇和呋喃醇与三-(2-羟乙基)-异氰酸尿酯缩聚磺化反应

用固体~(13)C NMR研究了呋喃醇(FA)和FA与三-(2-羟乙基)-异氰酸尿酯(THEIC)缩聚磺化反应及其产物结构,考察了2-甲基呋喃封端的FA线型齐聚物与甲醛水溶液在相转移催化剂(C_4H_9)_4N~+I~-和与大量硫酸作用下的反应特点,探讨了主要参数对反应的影响,阐明了缩聚交联磺化反应的规律,确定了产物的结构。

3~C-NMR 研究糠醇和糠醇与三■2—羟乙基■异氰尿酸酯缩聚磺化反应

80年代初,Kurihara 等开发的 PEC—1000复合膜,首次实现了工业规模的海水一级淡化,并在无机和有机水溶液的分离和浓缩方面显示了巨大潜力。据分析这种高效分离膜的功能分离层的主要结构成分是糠醇(FA)和三(?)2一羟乙基(?)异氰尿酸酯(THEIC)

Addition reactions of nitrones on the reconstructed C(100)-2 x 1 surfaces

In this paper, the reactions of nitrone, N-methyl nitrone, N-phenyl nitrone and their hydroxylamine tautomers (vinyl-hydroxylamine, N-methyl-vinyl-hydroxylamine and N-phenyl-vinyl-hydroxylamine) on the reconstructed C(100)-2 x 1 surface have been investigated using hybrid density functional theory (B3LYP), Moller-Plesset second-order perturbation (MP2) and multi-configuration complete-active-space self-consistent-field (CASSCF) methods. The calculations showed that all the nitrones can react with the surface "dimer" via facile 1.3-dipolar cycloaddition with small activation barriers (less than 12.0 kJ/mol at B3LYP/6-31g(d) level). The [2+2] cycloaddition of hydroxylamine tautomers on the C(100) surface follows a diradical mechanism. Hydroxylamine tautomers first form diradical intermediates with the reconstructed C(I 00)-2 x I surface by overcoming a large activation barrier of 50-60 kJ/mol (B3LYP), then generate [2+2] cycloaddition products via diradical transition states with negligible activation barriers. The surface reactions result in hydroxyl or amino-terminated diamond surfaces, which offers new opportunity for further modifications. (C) 2007 Elsevier B.V. All rights reserved.

Formulation of a basal medium for primary cell culture of the marine sponge Hymeniacidon perleve

Marine sponge cell culture is a potential route for the sustainable production of sponge-derived bioproducts. Development of a basal culture medium is a prerequisite for the attachment, spreading, and growth of sponge cells in vitro. With the limited knowledge available on nutrient requirements for sponge cells, a series of statistical experimental designs has been employed to screen and optimize the critical nutrient components including inorganic salts (ferric ion, zinc ion, silicate, and NaCl), amino acids (glycine, glutamine, and aspartic acid), sugars (glucose, sorbitol, and sodium pyruvate), vitamin C, and mammalian cell medium (DMEM and RPMI 1640) using MTT assay in 96-well plates. The marine sponge Hymeniacidon perleve was used as a model system. Plackett-Burman design was used for the initial screening, which identified the significant factors of ferric ion, NaCl, and vitamin C. These three factors were selected for further optimization by Uniform Design and Response Surface Methodology (RSM), respectively. A basal medium was finally established, which supported an over 100% increase in viability of sponge cells.

Sol-gel-derived alpha(2)-K7P2W17VO62/graphite/organoceramic composite as the electrode material for a renewable amperometric hydrogen peroxide sensor

The conductive alpha (2)-K7P2W17VO62/graphite/organoceramic composite was prepared by dispersing alpha (2)-K7P2W17VO62 and graphite powder in a propyltrimethoxysilane-based sol-gel solution; it was used as the electrode material for an amperometric hydrogen peroxide sensor. The modified electrode had a homogeneous mirror-like surface and showed well defined cyclic voltammograms. Square-wave voltammetry was employed to study the pH-dependent electrochemical behavior of c alpha (2)-K7P2W17VO62 doped in the graphite organoceramic matrix, and the experiment showed that both protons and sodium cations participated in the odor process. A hydrodynamic voltammetric experiment was performed to characterize the electrode as an amperometric sensor for the determination of hydrogen peroxide. The sensor can be renewed easily in a repeatable manner by a mechanical polishing step and has a long operational lifetime. (C) 2000 Elsevier Science B.V. All rights reserved.

Avian influenza virus infection induces differential expression of genes in chicken kidney

The pathogenic process of highly pathogenic avian influenza virus (HPAIV) infection is poorly understood. To explore the differential expression of kidney genes as a result of HPAIV infection, two cDNA libraries were constructed from uninfected and infected kidneys by suppression subtractive hybridization (SSH). Fifteen genes including IFN-stimulated genes (ISG12), lymphocyte antigen 6 complex locus E gene (LY6E), matrix Gla protein gene (MGP), lysozyme gene, haemopoiesis related membrane protein I gene, KIAA1259, MGC68696, G6pe-prov protein gene (G6PC), MGC4504, alcohol dehydrogenase gene (ADH), glutathione S-transferase gene (GST), sodium-dependent high-affinity dicarboxylate transporter gene (SDCT), Synaptotagmin XV (SytXV) and two novel genes were found significantly up-regulated or dramatically suppressed. Differential expression of these genes was further identified by Northern blot. Functional analysis indicated that the regulation of their expression might contribute to the pathogenic process of HPAIV infection. In contrast, the increased expression of three IFN-stimulated genes named ISG12, LY6E, and haemopoiesis related membrane protein 1 gene might reflect host defense responses. Further study showed that ISG12 protein failed to directly interact with NS1 protein of HPAIV which expressed simultaneously in the organs where HPAIV replication occurred, by use of BacterioMatch two-hybrid system. Therefore, our findings may provide new insights into understanding the molecular mechanism underlying the pathophysiological process of HPAIV infection in chicken. (c) 2007 Elsevier Ltd. All rights reserved.

UASB反应器处理维生素C生产废水研究

维生素C生产废水有机物浓度高、成分复杂、排放量大，是一种亟待处理的典型工业废水。本研究分别采用实验室规模和中试规模的升流式厌氧颗粒污泥床反应器（UASB）对该制药工业废水的厌氧生物处理工艺进行了较为深入的研究。同时采用两种不依赖于纯培养的分子生物学手段—变性梯度凝胶电泳（DGGE）和扩增核糖体DNA限制性分析（ARDRA）技术揭示了UASB反应器不同运行阶段污泥中微生物群落多样性组成及变化。此外，首次研究了零价铁（Fe0）在厌氧消化过程中对反应器运行及微生物群落结构的影响。 采用城市污水处理厂厌氧消化池絮状污泥和处理啤酒废水的颗粒污泥混合接种，小试中温（35±1℃）UASB反应器在其运行的第65天启动成功。反应器稳定运行阶段，在进水COD浓度为9000mg/L、水力停留时间为12h、容积负荷为13.6 kgCOD/m3.d条件下，其COD去除率稳定在85~90%之间，沼气产率达到4.5 m3/m3.d，沼气甲烷含量平均为72%。中试UASB反应器的接种污泥为厌氧消化污泥，其启动时间相对较长，为90天。在稳定运行期，反应器的进水COD浓度为8000~10000mg/L，水力停留时间和容积负荷分别保持在12~16h和10.6~14.2 kgCOD/m3.d范围，该阶段反应器的平均COD去除率稳定在85%左右，沼气产率平均为5.2m3/m3.d，沼气中甲烷含量为69%。上述结果表明中温UASB工艺用于维生素C生产废水处理是高效、可行的。 与对照反应器相比，添加Fe0的小试UASB反应器的COD去除率和沼气产量分别提高了6.5%和10.2%。同时，磷酸盐平均去除率为79%，比对照提高了64%，目前尚未见类似研究报道。在中试规模的UASB反应器中补充一定量的Fe0可缩短反应器启动时间，促进颗粒污泥的形成，该结果可能具有重要的应用价值。培养试验进一步表明，Fe0可以作为产甲烷菌还原CO2生成甲烷的电子供体。培养实验还表明，当系统中存在硝酸盐（0.40 mM）和硫酸盐（0.26 mM）时，Fe0促产甲烷过程受到一定程度的抑制。 采用细菌通用引物968F/1401R和341F/907R获得的PCR-DGGE指纹图谱均表明UASB反应器不同运行阶段细菌种群结构变化明显。小试和中试稳定期污泥的微生物多样性均高于各自初始接种污泥。产甲烷菌通用引物340F/519R的PCR-DGGE结果显示，虽然接种污泥中产甲烷菌的丰富度系数略低于稳定期，但总体而言，反应器运行期间产甲烷菌的种群组成相对稳定。 通过构建不同处理和不同运行阶段污泥样品的16S rRNA基因文库并对克隆基因进行限制性内切酶消化、测序分析。结果表明，稳定期两个反应器微生物群落结构相似，但与各自接种污泥差异明显。小试UASB反应器接种污泥中细菌的优势菌群分别为变形菌纲的δ亚纲（28.7%）和β亚纲（17.4%），至稳定运行期则演替为革兰氏阳性低GC菌群（21.9%）和变形菌纲的δ亚纲（14.0%）。中试反应器接种污泥Green non-sulfer bacteria（25.9%）和变形菌纲的δ亚纲（16.4%）类群占优势，而稳定期Green non-sulfer bacteria类群（17.9%）、革兰氏阳性低GC菌群（16.2%）和变形菌纲的δ亚纲（15.4%）为优势菌群。 产甲烷菌的优势克隆为SRJ 230、SRJ 26和SRJ 583，前两者分别与Methanosaeta concilii和未培养的Methanobacteria-like克隆Gran7M4的同源性达到97%和98%，后者与Methanomethylovorans. sp同源性为99%。接种污泥中上述类群占总克隆数量的比例较低。小试、中试接种污泥中产甲烷菌分别占7.8%和3.0%，但稳定运行期，该比例明显增加，分别达到21.9%和18.8%。上述结果表明启动期与稳定期污泥产甲烷菌种群组成相对稳定，但各类群数量明显增加。 添加Fe0的UASB反应器稳定运行期污泥中产甲烷菌比例（31.2%）高于对照反应器（24.2%）, 革兰氏阳性低GC类群、变形菌纲的δ亚纲比例差异不明显，而变形菌纲β亚纲（6.0%）和Green non-sulfer bacteria（9.2%）的比例均分别低于对照反应器（13.1%和17.1%）。该结果表明，添加Fe0使反应器内微生物群落多样性发生了显著变化。 此外，在添加Fe0的UASB反应器中检测到特异性的克隆SRJ 341和SRJ 320，两者分别同磷酸盐去除和铁氧化有关的克隆子Orbal D41和Clone195的序列相似性达95%和96%。这两个类群可能分别与磷酸盐去除及铁促产甲烷作用密切相关。这一结果尚未见报道。

离子注入选育维生素C高产菌

维生素C二步发酵混菌生产中，第一步由单菌发酵将D-山梨醇转化为L-山梨糖，第二步由产酸菌氧化葡萄糖酸杆菌与伴生菌巨大牙孢杆菌混菌发酵将L-山梨糖转化为2-酮基-L-古龙酸（维生素C的前体物）.利用离子注入技术，采用N<'+>离子束为诱变源，诱变维生素C二步混菌发酵中的产酸菌氧化葡萄糖酸杆菌.通过建立的维生素C高产菌筛选方法，以2-酮基-L古龙酸为筛选标记，获得一株维生素C高产菌株D14，其与生产用伴生菌巨大牙孢杆菌组成维生素C新混合菌系ND14，平均醇酸转化率比生产用混菌提高3.3个百分点.维生素C高产菌株D14及维生素C新混合菌系ND14生长特性及发酵特性为：维生素C高产菌株D14生长能力明显增强;维生素C新混合菌系D14于种子培养基中稳定期延长8-12小时，总生物量增加;在发酵过程中ND14生长明显快于CK，菌体总生物量增加.利用均匀设计的方法对新混合菌系ND14发酵培养基进行了优化，其结果为：最适玉米浆浓度为1.6%、最适尿素浓度为1.6%、最适MgSO<,4>浓度为0.03%、最适KH<,2>PO<,4>浓度为0.06%.

维生素C二步混菌发酵中L-山梨糖脱氢酶的研究

以氧化葡萄糖酸杆菌和巨大芽孢杆菌混合培养物的无细胞抽提液建立了Vc二步发酵离体实验系统.反应体系中加入山梨糖在pH7.0,35℃下保温24h，2-酮基-L-古龙酸（2KGA）生成.巨大芽孢杆菌胞外活性物质对离体系统的产酸没有影响，一定量的L-山梨糖脱氢酶可促进产酸.从氧化葡萄糖酸杆菌细胞质中分离纯化出L-山梨糖脱氢酶.L-山梨糖脱氢酶酶活与2KGA的形成呈正相关：L-山梨糖的转化是在细胞内进行的;亲缘关系相差甚远的伴生菌均能促进小菌产酸，且“伴生”效率相近;伴生菌通过促进产酸菌生长和提高其L-山梨糖脱氢酶比活力而提高发酵系统中L-山梨糖脱氢酶总活力，并且通过促进产酸菌合成新的RNA而增强其代谢力，从而促进产酸;通过对不同发酵时间L-山梨糖脱氢酶酶活及2KGA累积量的比较表明，此酶可作为生产上2KGA生成的实时监控的指示酶;环境因子通过提高酶活力促进产酸.

维生素C二步混菌发酵中伴生菌作用机制的研究

该文对维生素C“二步发酵法”第二步混合发酵中伴生菌对产酸菌——氧化葡萄糖酸杆菌作用机制进行了研究.除巨大芽孢杆菌外，还选用另外几种芽孢杆菌及酵母菌作为产酸菌的伴生菌.各伴生菌及其胞外液对产酸菌生长和2-酮基-L-古龙酸合成能力均有刺激作用，表明产酸菌的伴生菌具有广谱性.利用膜超滤浓缩、柱层析及电泳等技术，从伴生菌B2980胞外液中分离纯化出达电泳均一纯的高纯度活性蛋白质样品，并对其部分基本特性进行分析.结果表明：该活性物质是分子量为36300道尔顿，等电点为4.75的酸性蛋白质，并且是由一个亚基构成的单体蛋白.活性蛋白质的结晶呈规则的菱形形状，其水溶液显著提高产酸菌中SDH酶活性.试验中依伴生菌胞外液对产酸菌中SDH酶活性的作用，建立了该研究中目标活性物质的快速检测方法.