雨生红球藻抗氧化作用及藻粉质量安全性研究

以雨生红球藻为试材，依据雨生红球藻细胞形态学的特性，利用不同的胁迫处理得到不同的细胞类型，对不同类型的细胞的抗氧化机制进行了探讨，同时对抑制剂和其它环境胁迫因子的协同作用进行了分析。最后，对雨生红球藻粉进行了卫生安全性和毒理学评价，为雨生红球藻在动物和人体中的抗氧化作用的研究提供了第一手资料。 主要研究的结果如下： （1）三种细胞的抗氧化作用的强弱顺序为：红色细胞＞褐色细胞＞绿色细胞； （2）在没有外源活性氧的情况下，红色细胞的产生的活性氧最多，其次为褐色细胞，产生活性氧最少的是绿色细胞。但当有外源活性氧侵入后，绿色细胞活性氧含量最高，膜质过氧化程度急剧升高，而红色细胞无明显变化。 （3）在雨生红球藻细胞内，有两种抗氧化机制，一种是保护酶体系，另一种是抗氧化物质虾青素。不同细胞类型细胞的抗氧化机制的表现有所不同，绿色细胞中以保护酶体系为主，红色细胞中以虾青素为主。两种抗氧化机制相比较，虾青素的抗氧化作用远远大于保护酶体系，虾青素的作用更为迅速而且有效。 （4）不同的抗氧化机制有时空顺序，首先是细胞质中虾青素起作用，只有在虾青素不存在或者含量极低的情况下（绿色细胞中），抗氧化酶才发挥作用。保护酶作用的时间也略有不同，首先是SOD行驶其功能，以清除过多的O2—，产生的H2O2及其它的•OH再由POD去清除，最后APX和CAT发挥他们的作用。在绿色细胞中，SOD是自由基的第一道防线，也是清除自由基的关键酶。 （5）虽然CAT和APX都是叶绿体中清除H2O2的酶，但研究的结果显示，在雨生红球藻绿色细胞的叶绿体中，起关键作用的是APX，而不是CAT。 （6）氧化胁迫使SOD同工酶活力的增强，而使绿色细胞中POD产生了新的同工酶谱带（迁移率Rf＝0.29）。 （7）在轻度胁迫（高光强单独存在）的条件下，DPA增强了细胞的抗氧化能力；但在重度胁迫（高光强和氮饥饿共同存在）的条件下，DPA降低了雨生红球藻细胞的抗氧化能力。 雨生红球藻藻粉的质量安全性和毒理学实验的结果显示，无论是微生物学检验还是重金属含量均符合国家食品和保健品的质量标准；急性毒性试验及30天喂养试验均没有发现小鼠和大鼠有任何中毒症状和病理学病变。据此认为雨生红球藻藻粉作为食品和保健品原料是安全的。

ICP-OES测定浮游有孔虫的Mg/Ca比值及其在SST分析中的应用

海洋是驱动大气环流的主要“引擎”，海表温度（SST）又是揭示海洋环境变化的重要参数。利用有孔虫Mg/Ca比值恢复SST具有较高精密度，是目前恢复SST较成功的方法之一。本论文旨在建立一套有效的有孔虫清洗方法和ICP-OES测试有孔虫Mg/Ca比值的分析方法。 文中分析了53份西菲律宾海区(N18°40.23′，E135°37.11′；水深3225m)表层沉积物中浮游有孔虫Globigerinoides ruber（白色）Mg/Ca比值。结合本研究区的特点，文中使用的清洗方法是有孔虫Mg/Ca比值测试常用的“Mg”清洗方法，主要是由以下步骤构成：①用超纯水和甲醇在超声波水浴中清洗，②显微镜下剔除深色硅酸盐颗粒，③用氧化试剂去除有机质(加入30%H2O2和0.1M NaOH溶液在90℃左右的沸水浴中加热)，④酸洗(250μl 0.001N HNO3 超声波水浴中清洗10S)。清洗干净的样品经超纯硝酸溶解成溶液后，利用电感耦合等离子体发射光谱(ICP-OES)对其进行Mg/Ca比值的分析测试。仪器操作条件如下：辅助气流量（Ar）为0.5L/min（0.5L/min-1.5L/min），雾化器压力为0.2Mpa（0-0.4Mpa），泵速为20rpm（0-125rpm），高频输出功率（RF）为1150W（750W-1500W），火焰高度为15.5mm（8-21mm），通过多次重复测量一组Mg/Ca=3.333mmol/mol的标准溶液，其Mg/Ca短期精密度<0.5%,长期精密度为1%。53份样品之间Mg/Ca比值的RSD为2.7%，利用Lea(2000)建立的太平洋地区浮游有孔虫G. ruber(白色)的Mg/Ca与SST的校正公式:Mg/Ca(mmol/mol) ＝0.30exp[0.089×SST(℃)]，得到本研究区的SST为28℃±0.3℃。

海藻中植物生长素的提取、纯化及测定

生长素是一类重要的内源植物激素。它广泛存在于水生和陆生植物中，对其它生长发育起着至关重要的作用。国内外对海藻生长的相关研究报道较少，迄今尚未以对提取、纯化海藻中生长素的方法进行系统研究的报道，海藻生长系的定量分析也处在起步阶段，只有少量文献报道了个别海藻中生长素的含量。本论文通过较系统的实验，首次确定了一整套海藻生长素的提取、纯化及测定方法，并运用该方法首次测定和报道了我国有代表性的部分海藻中生长素的含量及组成。在分析比较现有方法的基础上，确定了以有机溶剂提取法提取海藻中的生长素，以萃取法和柱层析法对其进行分离纯化的初步方案，通过一系列实验对该方案中各关键步骤（包括前处理、提取、脱色、萃取纯化、碱液洗涤及柱层析纯化等）的具体操作条件进行了优选，从而建立了一种操作简便、提取率较高且重复性较好的海藻生长素的提取和纯化方法。运用已确定的提取、纯化及测定方法，对我国青岛海区的红、绿、褐三大类共16种有代表性海藻的生长素含量进行了测定。其生长素IAA含量为1.1～46.9ng/g FW，其中褐藻绳藻中生长素的含量在16种海藻中最高，为46.9 ng/g FW，是海藻肥的较佳资源种；鼠尾藻的含量最小，只有1.1 ng/g （鲜重）。运用TLC方法对所有海藻提取样品中生长素的组成进行了分析。大多数样品只有1个IAA显色点，其Rf值在0.43～0.48之间；鼠尾藻、海黍子和孔石莼样品未检出生长素；海带、蜈蚣藻和小珊瑚样品中除有IAA显色点外，还有1～2个其它斑点，这些斑咪的显色牲与吲哚类物质相同，是吲哚类生长素。

Sources and transport of dissolved and particulate organic carbon in the Mississippi River estuary and adjacent coastal waters of the northern Gulf of Mexico

Dissolved organic carbon (DOC), stable carbon isotopic (delta(13)C) compositions of DOC and particulate organic carbon (POC), and elemental C/N ratios of POC were measured for samples collected from the lower Mississippi and Atchafalaya rivers and adjacent coastal waters in the northern Gulf of Mexico during the low flow season in June 2000 and high flow season in April 2001. These isotopic and C/N results combined with DOC measurements were used to assess the sources and transport of terrestrial organic matter from the Mississippi and Atchafalaya rivers to the coastal region in the northern Gulf of Mexico. delta(13)C values of both POC (-23.8parts per thousand to -26.8parts per thousand) and DOC (-25.0parts per thousand to -29.0parts per thousand) carried by the two rivers were more depleted than the values measured for the samples collected in the offshore waters. Strong seasonal variations in delta(13)C distributions were observed for both POC and DOC in the surface waters of the region. Fresh water discharge and horizontal mixing played important roles in the distribution and transport of terrestrial POC and DOC offshore. Our results indicate that both POC and DOC exhibited non-conservative behavior during the mixing especially in the mid-salinity range. Based on a simple two end-member mixing model, the comparison of the measured DOC-delta(13)C with the calculated conservative isotopic mixing curve indicated that there was a significant in situ production of marine-derived DOC in the mid- to high-salinity waters consistent with our in situ chlorophyll-a measurements. Our DOC-delta(13)C data suggest that a removal of terrestrial DOC mainly occurred in the high-salinity (>25) waters during the mixing. Our study indicates that the mid- to high- (10-30) salinity range was the most dynamic zone for organic carbon transport and cycling in the Mississippi River estuary. Variability in isotopic and elemental compositions along with variability in DOC and POC concentrations suggest that autochthonous production, bacterial utilization, and photo-oxidation could all play important roles in regulating and removing terrestrial DOC in the northern Gulf of Mexico and further study of these individual processes is warranted. (C) 2004 Elsevier B.V. All rights reserved.

Stable carbon and nitrogen isotopic compositions of high molecular weight dissolved organic matter from four US estuaries

High molecular weight dissolved organic matter (HMW-DOM) represents an important component of dissolved organic carbon (DOC) in seawater and fresh-waters. In this paper, we report measurements of stable carbon (delta(13)C) isotopic compositions in total lipid, total hydrolyzable amino acid (THAA), total carbohydrate (TCHO) and acid-insoluble "uncharacterized" organic fractions separated from fourteen HMW-DOM samples collected from four U.S. estuaries. In addition, C/N ratio, delta(13) C and stable nitrogen (delta(15)N) isotopic compositions were also measured for the bulk HMW-DOM samples. Our results indicate that TCHO and THAA are the dominant organic compound classes, contributing 33-46% and 13-20% of the organic carbon in HMW-DOM while total lipid accounts for only <2% of the organic carbon in the samples. In all samples. a significant fraction (35-49%) of HMW-DOM was included in the acid-insoluble fraction. Distinct differences in isotopic compositions exist among bulk samples, the compound classes and the acid-insoluble fractions. Values of delta(13)C and delta(15)N measured for bulk HMW-DOM varied from -22.1 to -30.1parts per thousand and 2.8 to 8.9parts per thousand, respectively and varied among the four estuaries studied as well. Among the Compound classes, TCHO was more enriched in C-13 (delta(13)C = -18.5 to -22.8parts per thousand) compared with THAA (delta(13)C = -20.0 to -29.6parts per thousand) and total lipid (delta(13)C = -25.7 to -30.7parts per thousand). The acid-insoluble organic fractions, in general, had depleted C-13 values (delta(13)C = -23.0 to -34.4parts per thousand). Our results indicate that the observed differences in both delta(13)C and delta(15)N were mainly due to the differences in sources of organic matter and nitrogen inputs to these estuaries in addition to the microbial processes responsible for isotopic fractionation among the compound classes. Both terrestrial sources and local sewage inputs contribute significantly to the HMW-DOM pool in the estuaries studied and thus had a strong influence on its isotopic signatures. Copyright (C) 2004 Elsevier Ltd.

Bacterial roles in the formation of high-molecular-weight dissolved organic matter in estuarine and coastal waters: Evidence from lipids and the compound-specific isotopic ratios

High-molecular-weight dissolved organic matter (HMW-DOM, > 1,000 Daltons) is actively involved in the global biogeochemical cycling of many elements, but its carbon sources and detailed formation pathways are still not well understood. In this study, we measured bulk stable carbon and nitrogen isotopic ratios, lipid composition, and compound-specific carbon isotopic ratios of HMW-DOM samples collected from four U.S. estuaries (Boston Harbor/Massachusetts Bay, Delaware/Chesapeake Bay, San Diego Bay, and San Francisco Bay). Analytical results show (1) a fraction of HMW-DOM (lipid associated) in estuarine and coastal waters is derived from bacteria and phytoplankton; (2) this fraction of HMW-DOM is formed by various release processes of bacterial membrane components and bacterial reworking of phytoplankton-derived material; (3) this fraction of HMW-DOM is generally present in all samples from different coastal systems despite variable organic matter inputs and environmental conditions, suggesting an important bacterial role in HMW-DOM formation.

Sources and preservation of organic matter in Plum Island salt marsh sediments (MA, USA): long-chain n-alkanes and stable carbon isotope compositions

Elemental (TOC, TN, C/N) and stable carbon isotopic (delta(13)C) compositions and n-alkane (nC(16-38)) concentrations were measured for Spartina alterniflora, a C-4 marsh grass, Typha latifolia, a C-3 marsh grass, and three sediment cores collected from middle and upper estuarine sites from the Plum Island salt marshes. Our results indicated that the organic matter preserved in the sediments was highly affected by the marsh plants that dominated the sampling sites. delta(13)C values of organic matter preserved in the upper fresh water site sediment were more negative (-23.0+/-0.3) as affected by the C-3 plants than the values of organic matter preserved in the sediments of middle (-18.9+/-0.8) and mud flat sites (-19.4+/-0.1) as influenced mainly by the C4 marsh plants. The distribution of n-alkanes measured in all sediments showed similar patterns as those determined in the marsh grasses S. alterniflora and T. latifolia, and nC(21) to nC(33) long-chain n-alkanes were the major compounds determined in all sediment samples. The strong odd-to-even carbon numbered n-alkane predominance was found in all three sediments and nC(29) was the most abundant homologue in all samples measured. Both delta(13)C compositions of organic matter and n-alkane distributions in these sediments indicate that the marsh plants could contribute significant amount of organic matter preserved in Plum Island salt marsh sediments. This suggests that salt marshes play an important role in the cycling of nutrients and organic carbon in the estuary and adjacent coastal waters. (C) 2003 Elsevier Ltd. All rights reserved.

Variability in radiocarbon ages of biochemical compound classes of high molecular weight dissolved organic matter in estuaries

High molecular weight dissolved organic matter (HMW-DOM, > 1000 Da) represents a major fraction (> 30%) of dissolved organic carbon (DOC) in the ocean and thus plays an important role in the global biogeochemical cycling of carbon and many other elements. Its organic sources and formation mechanisms, however, are still not well understood especially in estuarine and coastal regions where multiple natural and anthropogenic sources contribute to total HMW-DOM. In this paper we report our measurements of natural radiocarbon (C-14) abundances and stable carbon isotope (C-13) compositions of the major biochemical compound classes: amino acids, carbohydrates and lipids separated from eight HMW-DOM samples collected from five US estuaries as part of our on-going study of sources, distribution and transport of chromophoric dissolved organic matter (CDOM) in estuarine and coastal waters. Distinct differences in both C-14 and C-13 values were found among the bulk HMW-DOM samples as well as the individual compound classes. Radiocarbon ages of the major compound classes varied by as much as 27,000 years in a single sample. The calculated average radiocarbon ages of the compound fractions of HMW-DOM indicate that the total lipid fraction is very "old", while the acid-insoluble fraction is slightly younger. Total amino acid and carbohydrate fractions, however, have relatively modern apparent C-14 ages. The significant variability in C-14 ages among the compound classes indicates not only multiple organic carbon sources but also different formation and turnover pathways controlling the cycling of different biochemical components of HMW-DOM in estuarine and coastal waters. (c) 2006 Elsevier Ltd. All rights reserved.

青海高原不同海拔地带生长的珠芽蓼光合特性的比较

对生长于青海高原不同海拔的珠芽蓼( Poligonum viviparum) 叶片的光合特性进行比较研究发现：随海拔升高叶绿素含量有降低趋势,叶绿素a/ b 比值及类胡萝卜素含量有增大趋势。不同海拔的珠芽蓼叶片和叶绿体的Fv/ Fo 、Fv/ Fm 和Rf d 值随海拔升高而增大, 表明随海拔升高, 其潜在光合活力增加。低温荧光测定显示,随海拔升高叶绿体中PSI 和PSI I 的相对荧光产量比值(PSI/PSI I) 减小。叶绿体蛋白质SDS - PA GE 结果表明,在28 - 32KD 附近电泳谱带的变化显著

UHF RFID 射频前端及其编解码设计

射频识别（Radio Frequency Identification，RFID）技术，是一种利用射频通信实现的非接触式的数据采集和自动识别技术（以下通称RFID技术）。而超高频射频识别技术（Ultra High Frequency RFID，UHF RFID）具有识别距离远、识别准确率高、识别速度快、抗干扰能力强等特点而成为当前研发的热点。UHF RFID读写器的难点就在于射频前端电路和基带编解码的设计，它们设计的好坏直接决定了读写器的性能好坏。 本文首先通过介绍UHF RFID读写器射频前端设计的基本原理，采用射频通用收发模块进行射频前端设计的方法，给出了以ADF7020收发芯片为核心的UHF RFID读写器的射频前端的整体设计和具体的实现电路，设计了包括射频收发电路、射频前端匹配电路、滤波电路、环行器电路、功率放大电路等。 其次根据EPC Gen-2的协议标准进行了UHF RFID读写器的基带编码解码的仿真设计，然后开发了以FPGA为核心的完整的数字基带硬件电路，实际调试表明整个基带编解码软件在硬件基带PCB板上运行状况良好，并能对EPC Gen-2的协议标准的命令进行正确的编码解码。 最后通过研究学习软件无线电的理论和开发方法，把UHF　RFID读写器的射频前端分成射频模拟前端和射频数字前端，给出了一种基于软件无线电思想的UHF RFID射频数字前端设计模型，并借助于SIMULINK中的信号处理工具箱对构建的数字前端的进行仿真验证，仿真结果验证了用软件无线电实现UHF RFID数字前端的可行性。

Direct synthesis and characterization of titanium-substituted mesoporous molecular sieve SBA-15

Ti-substituted mesoporous SBA-15 (Ti-SBA-15) materials have been synthesized by using a new approach in which the hydrolysis of the silicon precursor (tetramethoxysilane, TMOS) is accelerated by fluoride. These materials were characterized by powder X-ray diffraction patterns (XRD), X-ray fluorescence spectroscopy (Y-RF), N-2 sorption isotherms, diffuse-reflectance UV-visible (UV-vis) and UV-Raman spectroscopy, Si-29 MAS NMR, and the catalytic epoxidation reaction of styrene. Experiments show that Ti-SBA-15 samples of high quality can be obtained under the following conditions: F/Si greater than or equal to 0.03 (molar ratio), pH less than or equal to 1.0, aging temperature less than or equal to 80 degreesC, and Ti/Si less than or equal to 0.01. It was found that the hydrolysis rate of TMOS was remarkably accelerated by fluoride, which was suggested to play the main role in the formation of Ti-SBA-15 materials of high quality. There is no stoichiometric incorporation of Ti, and the Ti contents that are obtained are quite low in the case of the approach that is proposed. The calcined Ti-SBA-15 materials show highly catalytic activity in the epoxidation of styrene.