浊点萃取-石墨炉原子吸收光谱法测定环境样品中的镉

建立了浊点萃取分离富集石墨炉原子吸收光谱法测定环境样品中痕量镉的方法。浊点萃取选择8-羟基喹啉为螯合剂,Triton X-100为表面活性剂。在pH8～9、0.01%8-羟基喹啉和0.2%-Triton X-100、80℃水浴20 min的优化条件下,所建立方法的检出限为2.5 ng/L;加标回收率为94.6%～106.2%;对样品溶液进行富集的富集因子为17。利用该方法分别测定了2个实际水样和2个国家标准参考物质中的总镉含量,结果令人满意。

Aptamer-based label-free method for hemin recognition and DNA assay by capillary electrophoresis with chemiluminescence detection

An aptamer-based label-free approach to hemin recognition and DNA assay using capillary electrophoresis with chemiluminescence detection is introduced here. Two guanine-rich DNA aptamers were used as the recognition element and target DNA, respectively. In the presence of potassium ions, the two aptamers folded into the G-quartet structures, binding hemin with high specificity and affinity. Based on the G-quartet-hemin interactions, the ligand molecule was specifically recognized with a K (d)approximate to 73 nM, and the target DNA could be detected at 0.1 mu M. In phosphate buffer of pH 11.0, hemin catalyzed the H2O2-mediated oxidation of luminol to generate strong chemiluminescence signal; thus the target molecule itself served as an indicator for the molecule-aptamer interaction, which made the labeling and/or modification of aptamers or target molecules unnecessary. This label-free method for molecular recognition and DNA detection is therefore simple, easy, and effective.

反相高效液相色谱表征无定型聚芳醚酮（砜）成环解聚产物

建立了一种反相高效液相色谱表征无定型聚芳醚酮（砜）成环解聚产物的新方法.采用岛津VP-ODS C18反相色谱柱（150 mm×4.6 mm; 5 μm, i.d.）,以四氢呋喃/水为流动相,流速1.0 mL/min, 梯度淋洗方式;254 nm紫外检测,由此方法可将全部同系物组分有效地分离并可准确给出产物中各环状低聚体组分的百分含量.分析结果表明,酚酞聚醚酮、酚酞聚醚砜、双酚A聚砜经成环解聚反应高产率得到环状聚合体,最高成环率达97.57%.通过与激光质谱的比较证实了HPLC方法更适合于对成环解聚产物体系的表征.

In situ electrochemical SERS studies on electrodeposition of aniline on 4-ATP/Au surface

The electrochemical polymerization of 0.01 M aniline in 1 M H2SO4 aqueous solution on roughened Au surface modified with a self-assembled monolayer (SAM) of 4-aminothiophenol (4-ATP) has been investigated by in situ electrochemical surface-enhanced Raman scattering spectroscopy (SERS). The repeat units and possible structures of the electrodeposited polyaniline (PANI) film were proposed; i.e., aniline monomer is coupled in head-to-tail predominately at the C-4 of aniline and amine of 4-ATP, and the thin PANI film is orientated vertically to substrate surface. Simultaneous Raman spectra during potential scanning indicate clearly that the ultrathin PANI film (in initial growth of the film) consists of semiquinone radical cation (IP+), para-disubstituted benzene (IP and IP+) and quinine diimine (NP) while it is oxidized, and without quinine diimine and semiquinone radical cation while reduced. Meanwhile, the results confirm that 4-ATP monolayer shows a strong promotion on the electrodeposition of aniline monomer, and a possible polymerization mechanism was proposed.

Synthesis, structure and reactive mechanism of intermetallic W3Mg

Assisted by mechanical alloying and high-pressure technique, a new W3Mg intermetallic was formed. W3Mg amorphous mixture was obtained by mechanically alloying the pure metal powder mixtures at designated composition for 20 h. A new compound was found after the Subsequent high pressure and high temperature treatment. W3Mg intermetallic was identified as a tetragonal structure and the lattice parameter was a = 0.7880 nm, c = 0.7070 nm. The synthesis mechanism is also discussed in this paper.

Synthesis of a new aryl ether ketone polymer

The synthesis of a new aryl ether ketone polymer with an advantageous ratio of glass transition temperature to melting temperature is reported.

The phase inversion and morphology of nylon 1010 polypropylene blends

Noncompatibilized and compatibilized blends of nylon 1010/PP blends having five different viscosity ratios were prepared by melt extrusion. Glycidyl methacrylate-grafted-polypropylene (PP-g-GMA) was used as the compatibilizer to enbance the adhesion between the two polymers and to stabilize the blend morphology. The effect of the viscosity ratio on the morphology of nylon 1010/polypropylene blends was investigated, with primary attention to the phase-inversion behavior and the average particle size of the dispersed phase. The relationship between the mechanical properties and the phase-inversion composition was investigated as well. Investigation of the morphology of the blends by microscopy indicated that the smaller the viscosity ratio (eta(PP)/eta(PA)) the smaller was the polypropylene concentration at which the phase inversion took place and polypropylene became the continuous phase. The compatibilizer induced a sharp reduction of particle size, but did not have a major effect on the phase-inversion point. An improvement :in the mechanical properties was found when nylon 1010 provided the matrix phase. (C) 1996 John Wiley & Sons, Inc.

TRIS(TERT-BUTYLCYCLOPENTADIENYL)NEODYMIUM-MU-CHLORO-TRIS(TETRAHYDROFURAN)LITHIUM, [ND(ETA(5)-(T)BUCP)3(MU-CL)LI(THF)3]

The title complex, tris[2(eta5)-tert-butylcyclopentadi-enyl]-mu-chloro-1:2kappa2Cl-tris(tetrahydrofuran-1kappaO)lithiumneodymium, [Nd(C9H13)3(mu-Cl)Li(C4H8O)3], consists of the neutral moiety ((t)BuCp)3Nd linked to the cation [Li(thf)3]+ by a mu-Cl bridge

MISCIBILITY OF POLY(N-VINYL-2-PYRROLIDONE) WITH A COPOLYAMIDE

Blends of poly(N-vinyl-2-pyrrolidone) (PVP) with a copolyamide (CoPA) randomly composed of 1:1:1 (wt) nylon 6, nylon 66 and nylon 610 structural units were prepared by casting from a common solvent. They were found to be miscible and show a single, composition-dependent glass transition temperature (T(g)). The addition of PVP to CoPA significantly lowers the crystallinity owing to an increasing T(g) of the system. The observed miscibility is proposed to be the result of specific interactions between the proton acceptor groups of PVP and the amide groups of CoPA.

滤食性贝类养殖活动对海域生态系统的影响及生态容量评估

滤食性贝类以水体中的浮游植物和有机碎屑为主要食物，养殖海域的初级生产力水平、水动力学特性等生态环境因子的差异，不仅直接影响养殖贝类的产量，而且也与贝类养殖活动对生态环境的压力密切相关。由于养殖的种类、密度、方式及养殖海域的特性不同，关于贝类对生态环境的影响往往有不同的结果。本文以我国北方大连獐子岛扇贝底播海区和荣成桑沟湾贝类筏式养殖区为研究对象，采用现场调查、室内受控实验及生态数值模型模拟方法，分析研究了滤食性贝类对海域生态系统的影响，对这两个海域贝类养殖的生态容量进行了初步的评价。 主要结果： 1. 獐子岛海域底播贝类养殖活动对该海域生态系统的影响较小。非参数统计—符号检验的结果显示，养殖区与非养殖区之间的溶解性无机氮、磷酸盐浓度、氮磷摩尔比及浮游植物群落结构没有统计学上的差异（p>0.05）。但是从变化的趋势上来看，贝类养殖活动对水域环境的某些参数有一定程度的影响。例如，獐子岛底播贝类养殖海域的溶解性无机氮以氨氮为主，可能与贝类的代泄活动有关；不论是叶绿素浓度，还是网采浮游植物的生物量都是贝类高密度养殖区<贝类低密度养殖区<非养殖区（7月份除外），这种趋势可能与贝类的摄食压力有关。 桑沟湾各环境指标表现出明显的区域性。除春季外，非养殖区的DIN浓度高于各养殖区。在春季和冬季，贝类区的磷酸盐浓度显著降低；而硅酸盐浓度在夏季和秋季显著增大。综合分析DIN、PO4-P及SiO3-Si三个参数的四季变化，海带区、贝藻区及贝类区发生显著性变异的概率分别为25%，42%和50%，贝类区的变异较大。浮游植物、小型浮游动物的生物多样性指数都是以非养殖区为最高，贝类区的多样性指数最低。尤其是浮游动物的丰度，贝类区显著低于非养殖区。 2. 利用挪威的MOM (Modelling-Ongrowing fish farms-Monitoring)评价系统，评价了桑沟湾长期大规模的贝藻筏式养殖活动对底质环境的压力。在桑沟湾设10个取样站位，共获得66个底泥样品。比较了MOM－B评价系统的3组参数的季节变化特性。结果显示，底质条件属于1级，说明桑沟湾贝藻长期大规模的养殖活动对底质环境的压力较低。结合桑沟湾的环境及养殖特点，分析了压力较低的原因。 3. 经计算，2006年中国海水养殖的贝类和藻类使用浅海生态系统的碳可达396万吨，并通过收获从海中移出至少136.9万吨的碳。从1995年至2006年，养殖大型藻类和贝类累计移出的碳分别约为365万吨和893万吨，总计达1258万吨。证明了浅海的贝类和藻类养殖活动直接或间接地使用了大量的海洋碳，提高了浅海生态系统吸收大气CO2的能力。 4. 采用模拟现场生物沉积法测定了虾夷扇贝的滤水率、摄食率等生理指标及其与贝类个体大小、水温的关系。虾夷扇贝单位个体的滤水率与组织干重的关系符合幂函数方程CR=a×DWb，b值在0.45～0.65范围内；水温对虾夷扇贝滤水率的影响极其显著(p<0.01)，温度（T）与滤水率（CR）呈抛物线的关系：CR=-0.0009T2+0.0188T-0.0306，水温为10℃时，虾夷扇贝的滤水率、摄食较大。 5. 采用模拟现场流水法测定了3种滤食性贝类的食物选择性。紫贻贝、长牡蛎及栉孔扇贝分别对直径4m, 6m 和 8m颗粒的保留效率达到最大值；对小颗粒（直径2m）的保留效率分别为17%, 19% 和 8％。栉孔扇贝对食物数量和质量浓度的变化相对敏感，随着数量浓度的增加，栉孔扇贝倾向于摄食较大的颗粒；随着颗粒食物质量浓度的增加，倾向于摄食较小的颗粒。 6. 獐子岛海域四个航次的调查结果显示，叶绿素浓度在1.23～2.85mg.m-3范围内，均值为1.78±0.57 mg.m-3；初级生产力的变化范围为30.4～117.0 mg C. m-2.d-1，平均值为76.6±41.9 mg C. m-2.d-1。通过虾夷扇贝生物量断面调查，获得了虾夷扇贝的壳高频率分布情况，7月份的众数值出现在100 mm，10月份壳高的众数值为80 mm。利用以上测定的虾夷扇贝的滤水率等基本生物学特性，结合虾夷扇贝的年产量、海域面积和有关的水文状况等数据，计算了滤水效率、摄食压力、调节比率3个食物限制性指标参数，全年的均值分别为0.048, 0.31和 0.16，都小于1，说明目前该海域虾夷扇贝的养殖量未达到养殖容量。 7. 利用STELLA软件，建立的桑沟湾贝藻养殖的数值模型，模拟了叶绿素a浓度及氮磷营养盐的周年变化情况，及其对贝类养殖生物量变化的响应。以叶绿素a浓度为指标，初步探讨了桑沟湾贝类的生态容量。

海湾扇贝超氧化物歧化酶家族基因结构、表达和多态性分析

海湾扇贝Argopecten irradian Lamarck于1982年从美国引种到中国，由于具有较快的生长速度和很高的经济效益，海湾扇贝成为中国最主要的养殖贝类之一。近年来海湾扇贝养殖遇到了死亡率高等问题，深入开展海湾扇贝功能基因的研究，尤其是免疫相关基因及其机制研究并在此基础上寻找扇贝疾病防治的有效方法对海湾扇贝的健康养殖十分重要。 对于贝类免疫系统来说，其血细胞在先天性免疫防御中起着重要的作用。当受到外界病原侵染时，贝类血细胞的一个重要免疫反应就是吞噬作用。在吞噬病原过程中，受到病原侵染的贝类还会产生其他多种免疫反应，这些免疫反应将消耗大量的能量（ATP），产能的呼吸链会加速运转，由此也会引发与呼吸链相耦联的活性氧（ROS）的大量产生。这些活性氧具有极强的反应特性，能破坏病原微生物的结构和功能分子，实现对入侵病原的杀灭。利用活性氧对被吞噬的病原进行杀灭，这是吞噬作用消除病原抵御侵染的重要机制。但由于活性氧分子反应的非特异性，它们也会破坏宿主机体细胞内的功能蛋白分子、不饱和脂肪酸分子和核酸等，对细胞造成严重的伤害，进而导致机体生理机能的损伤和免疫系统的破坏。所以，及时消除病原感染机体内过量产生的ROS，维持相关细胞的正常代谢，对提高机体抵抗力和免疫力具有重要的作用。O2-是生物体内产生的第一种活性氧分子，其他的活性氧分子也是由它衍生而来，消除过量O2-是消除过量活性氧危害的第一步也是关键一步。生物体内，超氧化物歧化酶（SOD）是催化O2-发生歧化反应，消除O2-的关键酶。 首先，本文通过RACE方法获得了海湾扇贝SOD家族全部三种基因的cDNA全长并对其进行了序列的生物信息学分析，海湾扇贝AiCuZnSOD全长cDNA为1047个碱基，其中开放阅读框为459个碱基，编码152个氨基酸，与栉孔扇贝Chlamys farreri的CuZnSOD相似度为77.5%，与长牡蛎Crassostrea gigas的相似度为75%，与人的相似度为74.7%。AiMnSOD全长cDNA为1207个碱基，其中开放阅读框为678个碱基，编码226个氨基酸，序列比对结果发现AiMnSOD的氨基酸序列与虾夷扇贝Mizuhopecten yessoensis和皱纹盘鲍Haliotis discus hannai的相似度分别为85%和78.4%，与哺乳动物相似度也在68%~72%之间。AiECSOD全长cDNA为893个碱基，其中开放阅读框为657个碱基，编码218个氨基酸。AiECSOD与其它物种ECSOD相似度比较低。与线虫Brugia pahangi的相似度为27.9%，与疟蚊Anopheles gambiae的相似度为31.4%，与斑马鱼Danio rerio的相似度为27.8%，与人的相似度也只有28.6%，与同是贝类的长牡蛎ECSOD也只有28.1%的相似性。主要原因是AiECSOD的信号肽和肝磷脂结合区域在各物种中无同源性。 其次，采用qRT-PCR（quantitative real time PCR）方法分析三种SOD基因在不同组织中的表达情况，结果表明三种SOD基因的组织表达有所差异。AiCuZnSOD基因在鳃中表达水平最高，其次是血细胞和性腺，在外套膜、闭壳肌和肝胰脏表达水平较低。AiMnSOD基因在鳃中表达水平最高，其次是外套膜，在血细胞、性腺，而在肝胰脏和闭壳肌表达较弱。AiECSOD基因在血细胞中表达水平最高，其次是肝胰脏，在鳃、闭壳肌表达水平较低，而性腺和外套膜没有检测到。同时，采用qRT-PCR对鳗弧菌Vibrio angullarum感染后海湾扇贝血细胞中三种SOD基因mRNA表达变化进行了检测。AiCuZnSOD表达量在各个时间段没有显著差异(P > 0.05)。AiMnSOD的表达量在1.5 h时略有下降，在3 h时达到最高表达量，是空白组（0h）的3倍(P < 0.01)，从6 h到24 h表达量逐渐下降，24 h时表达量是空白组的1.6倍，24 h到48 h又稍有升高。AiECSOD的表达量在1.5 h时有所下降，是空白组的0.3倍（P < 0.05)，随后逐渐升高，在12 h时达到最高表达量，是空白组（0h）的4.5倍（P < 0.01），从24 h到48 h表达量逐渐下降并恢复到空白组的水平。在对照组，各个时间点没有显著差异（P > 0.05）。在鳗弧菌感染后，海湾扇贝三种SOD的表达并不一致，且差异比较显著。AiCuZnSOD被认为是构成性表达基因，其受外界刺激的影响最小，AiMnSOD和AiECSOD受刺激后表达上调比较明显。 第三，采用Genome-walking的方法得到了海湾扇贝三种SOD基因的基因组全长和近端启动子序列并对其进行了相关分析。AiCuZnSOD的基因组序列全长为4279bp，包含有4个外显子和3个内含子。AiMnSOD的基因组序列全长为10692bp，包含有4个外显子和3个内含子。AiECSOD的基因组序列全长为5276bp，包含有5个外显子和4个内含子。三种基因外显子和内含子的结合处序列遵循-AT/GT-原则。我们把海湾扇贝SOD家族的三个基因的近端启动子进行了比较分析。发现三种SOD在靠近起始密码子的位置都有Oct-1结合位点。三种SOD共有的转录位点有：Oct-1、C/EBPalp、Oct2.1、Sp-1和GATA-1。AiCuZnSOD和AiMnSOD共有的转录位点有：ICSBP、Ftz、TATA-box、C/EBPbeta和Antp。AiCuZnSOD和AiECSOD共有的转录位点有：AP-1和NFκB。AiMnSOD和AiECSOD共有的转录位点有：GR和ER。AiCuZnSOD独有的位点有：SRF、YY-1和NF-1。AiMnSOD独有的位点有：HNF-1、Hb、MEB、NF-muE1、Pit-1a和Eve。AiECSOD独有的位点有：CREB、RATA-alph、Kruppel-like和AP-3。 此外，通过构建原核表达载体，本研究对AiCuZnSOD和AiECSOD基因进行了体外重组表达，并对纯化的重组蛋白进行了酶活分析。酶活分析表明，重组AiCuZnSOD蛋白有较高的酶活和稳定性。 最后，我们对海湾扇贝三种SOD基因的部分区域，包括启动子、编码区，部分内含子区域进行了SNP检测，并对SOD基因部分SNP位点多态性和鳗弧菌敏感性进行了相关分析。三种SOD基因中，我们共发现了59个SNP位点，其中AiECSOD的SNP位点最多，特别是在启动子区，AiCuZnSOD和AiMnSOD多态性较低。其中AiCuZnSOD启动子区的-1739 T-C 位点的基因型和等位基因，AiECSOD启动子区的-498 A-T和-267 G-A等位基因频率，AiECSOD的第一个外显子38 Thr-Lys的多态性在敏感和抗菌群体中存在显著差异（P < 0.05）。

Cloning, characterization, and expression analysis of extracellular copper/zinc superoxide dismutase gene from bay scallop Argopecten irradians

Extracellular superoxide dismutase (ECSOD) is a major extracellular antioxidant enzyme that protects organs from damage by reactive oxygen species (ROS). We cloned a novel ECSOD from the bay scallop Argopecten irradians (AiECSOD) by 3' and 5' RACE. The full-length cDNA of AiECSOD was 893 bp with a 657 bp open reading frame encoding 218 amino acids. The deduced amino acid sequence contained a putative signal peptide of 20 amino acids, and sequence comparison showed that AiECSOD had low degree of homology to ECSODs of other organisms. The genomic length of the AiECSOD gene was about 5276 bp containing five exons and six introns. The promoter region contained many putative transcription factor binding sites such as c-Myb, Oct-1, Sp1, Kruppel-like, c-ETS, NF kappa B, GATA-1, AP-1, and Ubx binding sites. Furthermore, tissue-specific expressions of AiECSOD and temporal expressions of AiECSOD in haemocytes of bay scallops challenged with bacteria Vibrio anguillarum were quantified using qRT-PCR. High levels of expression were detected in haemocytes, but not in gonad and mantle. The expression of AiECSOD reached the highest level at 12 h post-injection with V. anguillarum and then returned to normal between 24 h and 48 h post-injection. These results indicated that AiECSOD was an inducible protein and that it may play an important role in the immune responses against V anguillarum. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.

西倾山地区植物区系研究

西倾山地区位于青海省东南部 ,北纬 33°80′～ 35°50′ ,东经 10 0°10′～ 10 2°4 0′。本地区共有种子植物 56科、 257属、 711种。区系特征如下 :(1)温带成分占 96 88% ,以绝对优势确定了本区系明显的温带性质。 (2 )世界成分多为衍生 ,更兼所含的中国特有属亦多为衍生 ,表明本区系的年轻性和衍生的性质。 (3)主要植被均属典型的高寒类型 ,它们的建群种亦多为典型的高寒植被的特征种。所以 ,本区系高寒植被典型 ,特征种典型 ,高寒区系特色明显。(4 )生态环境对本区系特征的塑造表现为高寒生态因子的选择和高山特化的作用强烈 ,而在一定程度上湿冷生性质和寒旱生性质的高山特化作用更为明显。西倾山地区的植物区系是唐古特地区的代表区系之一。但在中国特有种的分析中，本区系却与横断山和甘肃南部区系的联系最为密切，三者间的共有种最为丰富，有363种，占本区中国特有种的66.73%。如此大的相似性，无疑且有力地支持了李锡文等（1993）关于横断山地区的“川西北、甘西南、青东南小区”划分的观点。

LC-DAD-ESI-MS Characterization of Carbohydrates Using a New Labeling Reagent

A novel labeling reagent 1-(2-naphthyl)-3-methyl-5-pyrazolone (NMP) coupling to liquid chromatography with electrospray ionization mass spectrometry for the detection of carbohydrates from the derivatized rape bee pollen samples is reported. Carbohydrates are derivatized to their bis-NMP-labeled derivatives. Derivatives showed an intense protonated molecular ion at m/z [M+H](+) in positive-ion detection mode. The mass-to-charge ratios of characteristic fragment ions at m/z 473.0 could be used for the accurately qualitative analysis of carbohydrates. This characteristic fragment ion is from the cleavage of C2-C3 bond in carbohydrate chain giving the specific fragment ions at m/z [MH-CmH2m+1Om-H2O](+) for pentose, hexose and glyceraldehydes and at m/z [MH-CmH2m-1Om+1-H2O](+) for alduronic acids such as galacturonic acid and glucuronic acid (m = n - 2, n is carbon number of carbohydrate). No interferences for all aliphatic and aromatic aldehydes presented in natural environmental samples were observed due to the highly specific parent mass-to-charge ratio and the characteristic fragment ions. The method, in conjunction with a gradient elution, offered a baseline resolution of carbohydrate derivatives on a reversed-phase Hypersil ODS-2 column. The carbohydrates such as mannose, galacturonic acid, glucuronic acid, rhamnose, glucose, galactose, xylose, arabinose and fucose can successfully be detected.