N-亚硝基二甲胺化学电离的量子化学研究

用质谱化学电离和量子化学方法研究了致癌物质N-亚硝基二甲胺(NDMA)的结构及性质,优化了化学电离质谱中主要离子的构型;探讨了NDMA的质子化合物的形成途径,经NDMA及其质子化合物的静电势计算,阐述了NDMA的可能致癌机理。

电极体插入式长光程可见-紫外薄层光谱电化学池设计——二茂铁在二氯乙烷及苯甲烷中的行为

长光程光谱电化学池灵敏度高,还可以研究电极表面的吸附与修饰,用处很广,但文献报导的各种设计,多为组合式,构造复杂,电极电位控制不够完善,在非水溶剂中,尤其在低介电常数溶剂中,得不到理想的结果。作者曾报导一电流平行流向短光程薄层光谱电化学池,在薄层池内外各设电位参比点,得到了近于理想的伏安特性、本文报告一整体式内参比点设置的长光程薄层光谱电化学池,使用插入式聚四氟乙烯薄层电极,以池壁自然面当光透窗,

Distribution of uranium isotopes in the main channel of Yellow river (Huanghe), China

Uranium isotopes were measured in waters and suspended particulate matters (SPM) of the main channel of Yellow River, China that were sampled during four field trips between August 2005 and July 2006. The results show that the concentration of dissolved U (2.04-7.83 mu g/l) and the activity ratio of U-234/U-238 (1.36-1.67) are much higher than the average U concentrations and activity ratios of global major rivers. Mass balance calculations using the results of simulated experiments and measurement data show that the section of the Yellow River between Lanzhou and Sanmenxia has its dissolved U derived from two sources: suspended sediments (68%) and groundwater/runoff from loess deposits (32%). Both sources are related to the heavy erosion of the Chinese Loess Plateau. (C) 2008 Elsevier Ltd. All rights reserved.

Sequence analysis of Arthrospira maxima based on fosmid library

Arthrospira (Spirulina) (Setchell& Gardner) is an important cyanobacterium not only in its nutritional potential but in its special biological characteristics. An unbiased fosmid library of Arthrospira maxima FACHB438 that contains 4300 clones was constructed. The size distribution of insert fragments is from 15.5 to 48.9 kb and the average size is 37.6 kb. The recombination frequency is 100%. Therefore the library is 29.9 equivalents to the Arthrospira genome size of 5.4 Mb. A total of 719 sample clones were randomly chosen from the library and 602 available sequences, which consisted of 307,547 bases, covering 5.70% of the whole genome. The codon usage of A. maxima was not strongly biased. GC content at the first position of codons (46.9%) was higher than the second (39.8%) and the third (45.5%) positions. GC content of the genome was 43.6%. Of these sequences, 287 (47.7%) showed high similarities to known genes, 63 (10.5%) to hypothetical genes and the remaining 252 (41.8%) had no significant similarities. The assigned genes were classified into 22 categories with respect to different biological roles. Remarkably, the high presence of 25 sequences (4.2%) encoding reverse transcriptase indicates the RT gene may have multiple copies in the A. maxima genome and might play an important role in the evolutionary history and metabolic regulation. In addition, the sequences encoding the ATP-binding cassette transport system and the two-component signal transduction system were the second and third most frequent genes, respectively. These genomic features provide some clues as to the mechanisms by which this organism adapts to the high concentration of bicarbonate and to the high pH environment.

牙鲆Paralichthys olivaceus（♀）×夏鲆Paralichthys dentaus（♂）分子遗传学及数量遗传学研究

本论文采用扩增片段长度多态性（AFLP）技术对牙鲆Paralichthys olivaceus群体和夏鲆Paralichthys dentaus 群体进行了种群鉴定和遗传结构分析。共用8 对引物对两个群体（每个群体30 个个体）进行了分析。总共产生了379 个条带，条带大小在60－1000bp。牙鲆与夏鲆的遗传多态性分别为53.83%和22.22%。牙鲆群体的多态位点数显著低于夏鲆群体。牙鲆群体和夏鲆群体种的特异条带分别为27.3% 和 29.61%。两群体平均杂和度分别为0.0701 和 0.1556，香农氏多态指数分别为0.1044 和0.2387。群体内平均遗传距离分别为0.0705 （0.0214 到0.1377）和0.1656 （0.0629 到 0.2338），两群体间的平均遗传距离为0.6328。 AFLP 技术是进行种间群体结构分析的一个很好的分子标记方法，对牙鲆和夏鲆亲本群体进行遗传背景析为今后的杂交育种阐明种间杂交的遗传机理奠定基础。 在本论文中我们采用5×8 因子交配设计建立了牙鲆P. olivaceus（♀）× 夏鲆P. dentaus（♂）杂交家系，对生长相关性状的遗传力进行分析。所有家系都混合养殖在同一养殖池中，40 日龄，在养殖池中随机采集600 个个体，测量体长，体宽，体重等数量性状；然后提取杂交子代DNA 进行家系的鉴定。首先从牙鲆的微卫星中筛选了在牙鲆、夏鲆以及杂交子代扩增多态性较好的10 对微卫星引物（Po1, Po13, Po20, Po35, Po42, Po48, Po56, Po58, Po91, Poli 23TUF）。我们采用了三对引物对600 个个体进行了家系鉴定，共有400 多个体鉴定出自己的亲本，成功率达到80％以上。基于以上结果我们认为微卫星标记可以做为一个有效的标记来代替现实的物理标记，并且可以在子代的早期进行亲本的鉴定。 在养殖过程中，我们对自交和杂交家系生长状况进行了跟踪分析，在181刘清华 牙鲆（♀）×夏鲆（♂）分子遗传学及数量遗传学研究 博士学位论文II日龄之前杂交鲆体长和体重均为未表现出杂种优势，杂种优势率值始终为负值，但是绝对值在逐渐减小。从196 日龄之后杂交鲆杂种优势开始表现出来，并且在196 日龄之后杂种优势率显著的增加。256 日龄体长杂种优势率为14.29%，体重杂种优势率为59.78%, 271 日龄体长杂种优势率达到27.36%，体重杂种优势率为 102.32%。 本研究对杂交鲆在40 日龄的体长，体高、尾柄长、尾柄高，以及全长和体重的遗传力进行了估计，5 个性状的体长半同胞遗传力h2 S 为0.00146－0.719，5个性状的全同胞遗传力h2D 为0.00121－0.632，5 个性状的半同胞和全同胞的平均遗传力h2SD 为0.001335－0.6755。其中全长的遗传力最大。实验结果说明对早期幼鱼进行体长、体重等性状实施选育策略可能会显著影响后期杂交鲆的生长。

Isolation and characterization of novel marine Roseobacter clade members producing unique intracellular chromium-rich aggregates

The marine Roseobacter clade comprises one of the largest fractions of heterotrophic marine bacteria and accounts for about 16% of 16S rRNA gene clones retrieved from marine bacterioplankton. Their global distribution seems to be related to oceanic water masses and their environmental and biogeochemical properties. In this study, we report isolation and characterization of novel Roseobacter clade members from the Yellow Sea, China. Phylogenetic analysis of 16S rRNA gene sequences reveals that the new isolates (YSCB1, YSCB2, YSCB3 and YSCB4) are closely related to uncultured Arctic seawater bacterium R7967 (99.57-100% sequence identity) and to the cultured Roseobacter sp. DSS-1 (99.27-99.76% sequence identity) isolated from the southeastern coastal water of the USA. Interestingly, YSCB strains possess unique intracellular chromium-containing aggregates. Therefore, these novel Roseobacter clade members exhibit a peculiar property in mineral biogeneration. (c) 2006 Elsevier SAS. All rights reserved.

青海海北高寒草甸黄嘴朱顶雀亲鸟递食率

中国科学院海北高寒草甸生态系统定位站的黄嘴朱顶雀（Acanthis flavirostris)雌雄亲鸟的育幼行为数据收集于1999－2001年的3个繁殖季节（5－8月）。观察使用了一个闭路电视系统，包括放在鸟巢附近5－10cm处的摄像头和35－40m外的监视器。数据分析表明：亲鸟的递食率无年间变化；雌、雄鸟递食率没有差异；总递食率不随雏鸟日龄和日间不同时段改变，但雌鸟在傍晚以前的递食率低于雄鸟并在傍晚高于雄鸟。在雏鸟6日龄前，雌鸟总递食率低于雄鸟，且二者逐步逼近，然后稳定在同一水平。此种性别差异与雌鸟在递食以外所承担的，为雏鸟保温、遮阳以及清除雏鸟粪便等事务有关。这些结果与单配制鸟类亲本投资理论一致。

青海省湟水地区森林灌丛植被遥感分析及其主要特征

湟水地区地处黄土高原和青藏高原过渡带, 界于北纬36°02′～ 37°28′, 东经100°41′～103°04′之间。海拔1650～ 4395m , 总面积为16120 km2。本研究根据卫星遥感影像资料(以TM 为主) , 结合以往野外调查工作, 研究并综合分析了湟水地区的森林、灌丛植被及其主要特征。森林灌丛植被的遥感解译采用综合分析法。研究表明湟水地区森林灌丛植被具有明显的生态地理分布特征, 其分布多集中于黄土低山丘陵与中高山地形结合地带, 即黄土覆盖的边缘交错区域。这一空间分布特征可能与本区的黄土覆盖边缘地区的多样化生态地理特点存在一定的联系。生境的干湿状况直接影响本地区天然林的分布特征、森林灌丛植被覆盖率的高低、森林的类型结构和种类组成, 并成为人工造林效果的重要环境因素。本区森林灌丛植被长期受到人类活动的深刻影响, 具有人类活动的明显痕迹。人类活动的规模范围、作用方式、影响强度等因素成为本区森林灌丛植被及其生境变化与差异的重要原因之一。

三种嵩草群落中若干植物种的生态位宽度与重叠分析

本文利用Ｌｅｖｉｎｓ和Ｐｉａｎｋａ公式，在多维生态因子梯度上测定了海北地区高寒草甸三种嵩草（Ｋｏｂｒｅｓｉａ）群落中若干植物种的生态位宽度和生态位重叠。结果表明：三种嵩草群落中优势种群的生态位宽度都较大，其中小嵩草（Ｋ．ｐｙｇｍａｅａ）在土壤水势、光照强度和坡向等三维因子上的生态位宽度分别是０．９１８、０．８９６和０．９１０；矮嵩草（Ｋ．ｈｕｍｉｌｉｓ）和藏嵩草（Ｋ．ｔｉｂｅｔｌｃａ）在土壤水势维上的生态位宽度分别是０．８７５和０．８６６；植物种如具有较大的生态位，则种间的生态位重叠亦较高；植物种对间若有相似的生物学一生态学特征, 生态位重叠有降低的趋势小篙草和矮篙草在三维上的重叠值分别是0.671、0.719和0.686某些杂类草与优质牧草之间存有较大的重叠, 这主要与长期过度放牧、优良牧草受到抑制以及生境退化有关。

Changes in plant biomass and species composition of alpine Kobresia meadows along altitudinal gradient on the Qinghai-Tibetan Plateau

Alpine Kobresia meadows are major vegetation types on the Qinghai-Tibetan Plateau. There is growing concern over their relationships among biodiversity, productivity and environments. Despite the importance of species composition, species richness, the type of different growth forms, and plant biomass structure for Kobresia meadow ecosystems, few studies have been focused on the relationship between biomass and environmental gradient in the Kobresia meadow plant communities, particularly in relation to soil moisture and edaphic gradients. We measured the plant species composition, herbaceous litter, aboveground and belowground biomass in three Kobresia meadow plant communities in Haibei Alpine Meadow Ecosystem Research Station from 2001 to 2004. Community differences in plant species composition were reflected in biomass distribution. The total biomass showed a decrease from 13196.96 +/- 719.69 g/m(2) in the sedge-dominated K. tibetica swamp to 2869.58 +/- 147.52 g/m(2) in the forb and sedge dominated K. pygmaea meadow, and to 2153.08 +/- 141.95 g/m(2) in the forbs and grasses dominated K. humilis along with the increase of altitude. The vertical distribution of belowground biomass is distinct in the three meadow communities, and the belowground biomass at the depth of 0-10 cm in K. tibetica swamp meadow was significantly higher than that in K. humilis and K. pygmaea meadows (P < 0.01). The herbaceous litter in K. tibetica swamp was significantly higher than those in K. pygnaeca and K. humilis meadows. The effects of plant litter are enhanced when ground water and soil moisture levels are raised. The relative importance of litter and vegetation may vary with soil water availability. In the K. tibetica swamp, total biomass was negatively correlated to species richness (P < 0.05); aboveground biomass was positively correlated to soil organic matter, soil moisture, and plant cover (P < 0.05); belowground biomass was positively correlated with soil moisture (P < 0.05). However, in the K. pygnaeca and K. humilis meadow communities, aboveground biomass was positively correlated to soil organic matter and soil total nitrogen (P < 0.05). This suggests that the distribution of biomass coincided with soil moisture and edaphic gradient in alpine meadows.

高温高压和不同氧逸度条件下斜方辉石电导率的实验研究

在1．0～4．0GPa和1073～1423K及不同的氧分压条件下，借助YJ-3000t紧装式六面顶高压设备和Sarltron-1260阻抗／增益-相位分析仪，就位测定了斜方辉石的电导率。氧逸度控制由Ni＋NiO、Fe＋Fe3O4、Fe＋FeO和Mo＋MoO2四种固态氧缓冲剂完成的。实验结果表明：①在所选择的频率范围内（10^-1～10^6Hz），复阻抗对频率有很强的依赖性;②随着温度（T）升高，电导率（σ）增大，logσ与1／T之间符合Arrenhius关系.

太湖表层沉积物中多磷酸盐检出的环境意义

在氮限制型富营养化湖泊中，沉积多磷酸盐（Poly-P）可以用来示踪营养盐磷的输入和湖泊的富营养化过程。太湖是一个典型的磷限制型富营养化湖泊，通过对太湖表层沉积物中总有机碳（TOC）、总氮（TN）、总磷（TP）、氢氧化钠可提取磷（NaOH-P）以及Poly-P 的提取分析，初步探讨了太湖营养盐磷输入的历史记录，并揭示了该湖Poly-P 的主要来源和保存机制。太湖Poly-P 的质量浓度较低，变化范围为0.004~0.065 mg·g-1。NaOH-P 占TP 组成的22%，是太湖沉积物总磷的主要组成部分之一。结果显示，在湖泊水体藻类生物量较大和NaOH-P 是沉积物TP 重要组成部分的磷限制型湖泊中，Poly-P 也是沉积物磷汇组成的一个重要部分，同时还是一个可以反映由人为磷输入增大导致湖泊富营养化程度加剧的敏感指标。

1，3，5-三氯苯在土壤沉积物水体系中的吸附过程研究

以自然土壤、沉积物样品为研究对象，研究了1，3，5-三氯苯在样品上的等温吸附过程。结果表明，线性模型和Freundlich模型能较好地拟合所有样品的等温线，而双区位反应模型(DRDM)适用范围有限。研究表明，三氯苯的吸附容量大小主要取决于样品中有机碳的含量，并且与不可提取态有机质和粘土矿物含量有一定的关系。以自然土壤、沉积物样品为研究对象，研究了1，3，5-三氯苯在样品上的等温吸附过程。结果表明，线性模型和Freundlich模型能较好地拟合所有样品的等温线，而双区位反应模型(DRDM)适用范围有限。研究表明，三氯苯的吸附容量大小主要取决于样品中有机碳的含量，并且与不可提取态有机质和粘土矿物含量有一定的关系。

云南潞西上芒岗金矿红色粘土化作用及其环境效应

上芒岗卡林型金矿床的强烈红土化作用，形成了上部红色粘土型金矿体，产生了一定范围的次生地球化学异常。金矿区红色粘土剖面可分为表土带、坡积带、钙华－沼泽带、残积带、腐泥带和基岩带 。在原生卡林型金矿红土化作用过程中，黄铁矿、毒砂、辉锑矿、方铅矿、闪锌矿等硫化物矿物发生氧化作用，S、As、Sb、Pb等有有害元素将被有效释放进入地下水和红色粘土中，进而造成地下水和土壤的污染。