雨生红球藻中虾青素合成相关酶基因的转录调控序列分析

虾青素是一种具有极强抗氧化活性的类胡萝卜素，具有广泛的应用价值。雨生红球藻是一种单细胞绿藻，在逆境胁迫条件下能够大量合成并迅速积累虾青素，其积累量最高可达细胞干重的4%，从而成为目前首选的天然虾青素合成工具。但是，虾青素的大量积累总是发生在不适于生物量积累的环境胁迫条件下，虾青素积累与生物量积累之间成为一对矛盾，制约着虾青素大量生产。 异戊烯焦磷酸异构酶（IPI）、β-胡萝卜素酮化酶（BKT）和β-胡萝卜素氧化酶（CRTO）是虾青素合成过程中的相关酶。已有研究结果表明，这些酶基因的表达调控至少是部分发生在转录水平上的，这就为我们从转录水平上研究虾青素生物合成关键酶基因的调控机制提供了重要线索。 本文研究结果如下： 1. 利用基因组步移的方法克隆了两条异戊烯焦磷酸异构酶基因（ipi）的5’上游侧翼序列（1.8kb和2.5kb），预示着ipi的转录由不止一个启动子调控。 2. 利用上述方法克隆了两条β-胡萝卜素氧化酶基因（crtO）5'上游侧翼序列（1kb和2kb）。以lacZ为报告基因的瞬间表达实验结果表明，长度为320bp(-682/-363)的crtO 5'上游侧翼序列具有很强的启动转录活性，提示这段序列包含了启动子的结构。 3. 利用凝胶阻滞的方法研究了雨生红球藻中bkt强启动转录活性区域，即 309bp(-617/-309)启动子区域的转录因子结合位点，并发现在-396/-338的59bp区域内存在特异的核蛋白结合位点。通过序列分析，发现此59bp区域并不包含TATA或者CAAT-box，而是存在对光、缺氧、p-香豆酸及激素反应的G-box。 4. 根据国外已经获得的ipi和crtO全长cDNA序列，利用长距离PCR法从红球藻基因组中扩增到基因组序列。发现ipi和crtO均包含6个外显子和5个内含子，内含子的剪切位点基本符合GU-AG规律。并通过似然比检验（Likelihood ratio test）的方法发现两基因在进化过程中存在着正选择现象。 这些工作为下一步继续寻找与上述特定DNA调控区域特异结合的反式作用因子（蛋白质因子）奠定了基础。

Clay surface modification and its coagulation of red tide organisms

Surface modification of montmorillonite by means of Mg2+ insertion reaction has been studied and a positively charged montmorillonite has been prepared. The effects of preparation temperature and Mg2+ concentration on the positive charge property of the clay and on the clay coagulating Heterosigma akashiwo have been studied. The results showed that the modified clay enhanced the coagulation and the used amount decreased to 1/5-1/10 of the original. The removal rates of Heterosigma akashiwo were correlated positively with positive charge on the clay in accordance with theoretical model.

Elemental carbon record of paleofire history on the Chinese Loess Plateau during the last 420 ka and its response to environmental and climate changes

An elemental carbon (EC) record, covering the last 420 ka, was reconstructed using chemical oxidation method on a loess and paleosol sequence from the Lingtai section on the Chinese Loess Plateau. The EC record reveals the paleofire history and its relationship with climate and vegetation changes on the Chinese Loess Plateau. Our results show that the EC abundance is generally higher in the paleosols than in the loess layers, showing a glacial/interglacial pattern, which is coincident with biomass changes. This variation pattern indicates that paleofires were intensified when biomass accumulated and climate changed abruptly especially from wet to dry conditions. The EC abundance increases sharply at similar to 130 kaB.P., indicating a dramatic change in the vegetation and climate variation patterns. The occurrence of a peak value with the highest average EC abundance in the Holocene may reflect the occurrence of a major climate event at similar to 6 kaB.P., and may also be partly due to more frequent anthropogenic fire usages. (c) 2007 Elsevier B.V. All rights reserved.

Temporal and spatial variability in nitrogen uptake kinetics during harmful dinoflagellate blooms in the East China Sea

Temporal and spatial variability in the kinetic parameters of uptake of nitrate (NO3-), ammonium (NH4+), urea, and glycine was measured during dinoflagellate blooms in Changjiang River estuary and East China Sea coast, 2005. Karenia mikimotoi was the dominant species in the early stage of the blooms and was succeeded by Prorocentrum donghaiense. The uptake of nitrogen (N) was determined using N-15 tracer techniques. The results of comparison kinetic parameters with ambient nutrients confirmed that different N forms were preferentially taken up during different stages of the bloom. NO3- (V-max 0.044 h(-1); K-s 60.8 mu M-N) was an important N source before it was depleted. NH4+ (V-max 0.049 h(-1); K-s 2.15 mu M-N) was generally the preferred N. Between the 2 organic N sources, urea was more preferred when K. mikimotoi dominated the bloom (V-max 0.020 h(-1); K-s 1.35 mu M-N) and glycine, considered as a dominant amino acid, was more preferred when P. donghaiense dominated the bloom (V-max 0.025 h(-1); K-s 1.76 mu M-N). The change of N uptake preference by the bloom-forming algae was also related to the variation in ambient N concentrations. Published by Elsevier B.V.

Fucoidan protects against dopaminergic neuron death in vivo and in vitro

Parkinson's disease is a neurodegenerative disorder of uncertain pathogenesis characterized by a loss of dopaminergic neurons in substantia nigra pars compacta, and can be modeled by the neurotoxin 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP). Oxidative stress may contribute to MPTP- and Parkinson's disease-related neurodegeneration. Fucoidan is a sulfated polysaccharide extracted from brown seaweeds which possesses a wide variety of biological activities including potent antioxidative effects. Here we investigated the effect of fucoidan treatment on locomoter activities of animals, striatal dopamine and its metabolites and survival of nigral dopaminergic neurons in MPTP-induced animal model of Parkinsonism in C57/BL mice in vivo and on the neuronal damage induced by 1-methyl-4-phenylpyridinium (MPP+) in vitro, and to study the possible mechanisms. When administered prior to MPTP, fucoidan reduced behavioral deficits, increased striatal dopamine and its metabolites levels, reduced cell death, and led to a marked increase in tyrosine hydroxylase expression relative to mice treated with MPTP alone. Furthermore, we found that fucoidan inhibited MPTP-induced lipid peroxidation and reduction of antioxidant enzyme activity. In addition, pre-treatment with fucoidan significantly protected against MPP+-induced damage in MN9D cells. Taken together, these findings suggest that fucoidan has protective effect in MPTP-induced neurotoxicity in this model of Parkinson's disease via its antioxidative activity. (C) 2009 Elsevier B.V. All rights reserved.

Preparation of low-molecular-weight and high-sulfate-content chitosans under microwave radiation and their potential antioxidant activity in vitro

In the present paper microwave radiation has been used to introduce N-sulfo and O-sulfo groups into chitosan with a thigh degree of substitution and low-molecular weight. The sulfation of chitosan was performed in microwave ovens. It was found that microwave heating is a convenient way to obtain a wide range of products of different degrees of substitution and molecular weight only by changing reaction time or/and radiation power. Moreover, microwave radiation accelerated the degradation of sulfated chitosan, and the molecular weight of sulfated chitosan was considerably lower than that obtained by traditional heating. There are no differences in the chemical structure of sulfated chitosan obtained by microwave and by conventional technology. FTIR and C-13 NMR spectral analyses demonstrated that a significantly shorter time is required to obtain a satisfactory degree of substitution and molecular weight by microwave radiation than by conventional technology. In this present paper, we also determined antioxidant activity of low-molecular-weight and high-sulfate-content chitosans (LCTS). The results showed LCTS could scavenge superoxide and hydroxyl radical. Its IC50 is 0.025 and 1.32mg/mL, respectively. It is a potential antioxidant in vitro. (C) 2004 Published by Elsevier Ltd.

Corrosion behaviour of hot dip zinc and zinc-aluminium coatings on steel in seawater

A comparative investigation of hot dip Zn-25Al alloy, Zn-55Al-Si and Zn coatings on steel was performed with attention to their corrosion performance in seawater. The results of 2-year exposure testing of these at Zhoushan test site are reported here. In tidal and immersion environments, Zn-25Al alloy coating is several times more durable than zinc coating of double thickness. At long exposure times, corrosion rate for the Zn-25Al alloy coating remains indistinguishable from that for the Zn-55Al-Si coating of similar thickness in tidal zone, and is two to three times lower than the latter in immersion zone. The decrease in tensile strength suggested that galvanized and Zn-55Al-Si coated steel suffer intense pitting corrosion in immersion zone. The electrochemical tests showed that all these coatings provide cathodic protection to the substrate metal; the galvanic potentials are equal to - 1,050, - 1,025 and - 880 mV (SCE) for zinc, Zn-25Al alloy and Zn-55Al-Si coating, respectively, which are adequate to keep the steel inside the immunity region. It is believed that the superior performance of the Zn-25Al alloy coating is due to its optimal combination of the uniform corrosion resistance and pitting corrosion resistance. The inferior corrosion performance by comparison of the Zn coating mainly results from its larger dissolution rate, while the failure of the Zn-55Al-Si coating is probably related to its higher susceptibility to pitting corrosion in seawater.

高寒草甸不同海拔梯度下多年生黄帚橐吾的克隆生长特征

通过对多年生植物黄帚橐吾(Ligularia virgaurea)在四个不同海拔梯度下的克隆生长行为进行研究,结果表明:(1)资源水平(土壤养分)、干扰和群落性质影响间隔物(spacer)长度的变化.在第一和第四海拔梯度中(土壤养分较丰富)间隔物长度较短,而在第二和第三海拔梯度中(土壤养分较贫乏)间隔物长度较长,说明其能对资源水平和生境优劣作出反应.(2)分枝强度(branching intensity)随资源水平的增加而上升.(3)在高海拔、寒冷和资源较丰富的生境中,其生物量的投资偏向于地下部分生物量,说明黄帚橐吾的资源分配方式受到环境资源条件和群落性质的影响.

Suitability of extractants for predicting available sulfur in natural grassland in the Inner Mongolia steppe of China

It was the objective of this study to compare the suitability of different extractants for predicting the availability of sulfur (S) in natural grassland in a sulfur response trial on three different soil types in the Inner Mongolia steppe of China. For soil analysis, seven different extractants have been employed. The inorganic SO4-S concentration was determined by ion chromatography. Additionally, in the Ca(H-2-PO4)(2) extract the total soluble S was determined employing turbidimetry. Weak salt solutions (0.15% CaCl2, Ca(H2PO4)(2), and KH2PO4) extracted similar amounts Of SO4-S. Extraction with 0.025 M KCl provided the lowest SO4-S values. Deionized water dissolved significantly more SO4-S in the control plots than most weak salt extractants. The concentration of soluble organic S decreased in the control plots after 100 days of plant growth, indicating that the organic S pool contributed significantly to the S nutrition of the forage crops. Significant relationships among the SO4-S in the soil determined in different extracts and crop yield, sulfur content in the forage, and total sulfur uptake were only found for the Ca(H2PO4)(2) extract. In general, the correlation coefficients proved to be unsatisfactory for field experimentation.

虚拟制造系统体系结构及实现方法研究

当前的市场变化莫测，竞争空前激烈，企业发展过程中困难与机遇并存。自然资源的匮乏、能源危机以及严厉的环保法规，使企业的产品与生产受到诸多因素的制约。企业的产品除要最大限度地满足用户多样化个性化的要求外，还必须考虑社会效益与环保效益。为此，企业在产品设计开发的早期，就应该考虑产品生命周期各阶段中的所有重要因素，优化产品设计与生产，降低成本，提高质量，增强功能。快速产品开发能力成为企业在多变的市场竞争中获胜的首要因素之一。而企业传统的设计开发方式远远满足不了需要，必须寻找新的途径以适应形势的变化。在这种需求的呼唤下，虚拟制造技术（Virtual Manufacturing, VM）应运而生。虚拟制造就是“在计算机中虚拟地制造出数字产品”。通过在计算机中仿真产品的制造过程，虚拟制造能够分析并改进产品设计方案，优化产品生产，控制产品成本，增强企业在各个层次上的管理与决策能力。本文将就虚拟制造技术进行深入的研究，主要从以下几个方面展开工作：◆总结虚拟制造技术的主要思想，探讨其研究的主要内容；◆分析虚拟制造系统的组成及类型，研究虚拟制造系统与实际制造系统的关系；给出用户对虚拟制造系统的要求及构建虚拟制造系统的技术条件；在此基础上，深入分析实施虚拟制造的障碍，提出虚拟制造系统的一般实施策略；◆给出虚拟制造技术对硬件系统的要求，并提出支持虚拟制造的硬件基础结构；◆深入研究虚拟制造系统的体系结构，从不同的侧面加以论述，提出一种便于实施的新的虚拟制造技术体系结构；◆根据虚拟制造系统的要求，初步研究虚拟制造系统的建模问题，给出虚拟制造系统建模一般方法；以此为基础，研究如何建造虚拟制造系统的虚拟环境，给出建造虚拟制造环境的面向对象方法；◆研究虚拟制造环境中物理实体的控制方法问题，讨论如何有效地在虚拟环境中实现虚拟对象的行为特征，逼真地模拟真实的制造活动与制造过程；研究虚拟制造环境与实际制造环境的联接问题，给出解决办法；◆根据前面的理论研究，结合国家九五攻关课题，以攻关课题中研制的并联桁架结构机器人数控机床为主要对象，系统地研究了虚拟制造环境的建立方法以及具体实现，实初步建立起一个试验性的小型虚拟制造环境。最后对本文的工作进行总结，得出研究结论以及进一步的研究方向。

高温高压和不同氧逸度控制下单晶橄榄石电导率的实验研究

在1．0—4．0GPa，1123—1473K和控制氧逸度（Ni＋NiO，Fe＋Fe3O4，Fe＋FeO和Mo＋MoO2等4种氧缓冲剂）的条件下，借助YJ-3000t紧装式六面顶高温高压设备和Sarhron-1260阻抗／增益-相位分析仪，就位测定了橄榄石的电导率．实验结果表明：（1）在测定的频率范围（10^3-10^6Hz），样品的电导率对频率具有很强的依赖性；（2）随着温度（T）升高，电导率（σ）增大，lgσ与1／T之间符合Arrhenius关系；（3）在Fe＋Fe3O4氧缓冲条件下，随着压力升高，电导率降低，而活化焓和指前因子增大，并给出样品的活化能和活化体积分别为（1．25±0．08）eV和（0．105±0．025）cm^3·mol；（4）在给定的压力和温度下，随着氧逸度增加，电导率增大，活化焓降低；（5）小极化子导电机制可为橄榄石在高温高压下的导电行为提供合理的解释.

湘南中生代花岗质岩石成岩成矿的时限

位于南岭中段的湘南地区，中生代花岗质岩石广泛分布；该区W、Sn、Pb、Zn、Mo、Bi等金属矿床密集产出，很多钨、锡矿床达到大型、超大型规模，且找矿潜力巨大，构成一个世界级的有色金属矿集区。最近大量的同位素年代学研究表明，南岭中段钨、锡、铅锌等金属的成矿是一个爆发性、区域性的地质事件，成矿时间高度集中，成矿时限主要在150～160Ma之间，与该区主要花岗岩的成岩时间相当吻合；对单个钨、锡矿床而言，其矿区的成岩、成矿存在着一种准同期性，即成矿与矿区花岗岩的成岩基本上是同时的、或稍晚于花岗岩的成岩作用。因此，该区中生代的花岗岩与钨锡成矿作用具有明显的时、空联系。南岭中段花岗岩大规模的侵入和钨、锡等金属的爆发性成矿均形成于一种岩石圈伸展减薄、地壳拉张的构造环境，可能与华南中生代第二幕岩石圈伸展事件密切相关。

Application of liquid pre-column capillary electrophoresis technique to the study of interaction between drug enantiomers and human serum albumin

Based on the chiral separation of several basic drugs, dimetindene, tetryzoline, theodrenaline and verapamil, the liquid pre-column capillary electrophoresis (LPC-CE) technique was established. It was used to determine free concentrations of drug enantiomers in mixed solutions with human serum albumin (HSA). To prevent HSA entering the CE chiral separation zone, the mobility differences between HSA and drugs under a specific pH condition were employed in the LPC. Thus, the detection confusion caused by protein was totally avoided. Further study of binding constants determination and protein binding competitions was carried out. The study proves that the LPC technique could be used for complex media, particularly the matrix of protein coexisting with a variety of drugs.