Depletion of Vipp1 in Synechocystis sp PCC 6803 affects photosynthetic activity before the loss of thylakoid membranes

A vipp1 mutant of Synechocystis sp. PCC 6803 could not be completely segregated under either mixotrophic or heterotrophic conditions. A vipp1 gene with a copper-regulated promoter (P-petE-vipp1) was integrated into a neutral platform in the genome of the merodiploid mutant. The copper-induced expression of P-petE-vipp1 allowed a complete segregation of the vipp1 mutant and observation of the phenotype of Synechocystis 6803 with different levels of vesicle-inducing protein in plastids 1 (Vipp1). When P-petE-vipp1 was turned off by copper deprivation, Synechocystis lost Vipp1 and photosynthetic activity almost simultaneously, and at a later stage, thylakoid membranes and cell viability. The photosystem II (PSII)-mediated electron transfer was much more rapidly reduced than the PSI-mediated electron transfer. By testing a series of concentrations, we found that P-petE-vipp1 cells grown in medium with 0.025 mu M Cu2+ showed no reduction of thylakoid membranes, but greatly reduced photosynthetic activity and viability. These results suggested that in contrast to a previous report, the loss of photosynthetic activity may not have been due to the loss of thylakoid membranes, but may have been caused more directly by the loss of Vipp1 in Synechocystis 6803.

藏酋猴(Macaca thibetana)电刺激采精、精液冻存和精子活力的检测

本文研究中国特有的藏酋猴(Macaca thibetana)电刺激采精、精液冻存及精子活力检测。用电刺激方案[(DDR)_(17-c)V]：延搁(delay)17毫秒、间期(duration)17毫秒、刺激频率17脉冲／秒、单方波变电压连续刺激，对笼养藏酋猴进行电刺激采精，测定精液的各种特征参数，包括每次射精量、液化率、精子密度、运动精子的百分率、死活精子以及异常精子比例。并与其它非人灵长类进行了比较。在精液冻存实验中，通过对不同的防冻液、不同的降温程序及防冻液分散系的比较研究，从而确定了适于藏酋猴精液冻存的冻存方案：PSF-4%的甘油-TH-7.5%的小牛血清(PSF-TH/FBS-G)和PSF-MDM。用前一方案冻存藏酋猴精液，复苏运动度为63.58±0.06%；精子的存活率为90.14±0.03%(n=5)。冻存精液用金黄地鼠裸穿透分析法检测，结果表明具有相应新鲜精液穿透力的51.90±0.08%。后一冻存方案能保存88.00±1.03%的运动精子，但运动寿命较短。研究结果表明：1).刺激方案(DDR)_(17-c)V适于藏酋猴的电刺激采精。2).藏酋猴的精液量和精子数在已有过研究的非人灵长类动物中是最多的，藏酋猴有可能成为较理想的精子生物学研究用的非人灵长类动物。3).脂蛋白对维持精子膜的完整可能有重要作用。4).接近生理条件的防冻剂分散系有助于精液的冻存。5).两种冻存方案PSF-TH/FBS-G和PSF-MDM均适于藏酋猴的精液冻存。

南海北部海陆过渡带地壳平均速度及莫霍面深度分析

南海北部海陆过渡带是一条深地震探测的空白带,其地壳结构研究不仅可以揭示华

Langmuir-Blodgett films based on europium-substituted heteropolytungstate and their luminescence properties

Several new hybrid organic-inorganic Langmuir-Blodgett (LB) films containing europium-substituted hetero-polytungstate Eu (XW11O39)(2)''(-) (X=Ge, Si, B) were successfully obtained using LB technique. When the heteropolytungstate anions are dissolved in the subphase, dimethyldioctadecylammonium bromide compression isotherms have been modified, which shows that the polyanions interact with the monolayer. Y-type LB films were obtained from the systems. Low-angle X-ray has shown that these LB films have well-defined lamella. The LB films were characterized by luminescence spectra and the characteristic luminescence behavior for europium-substituted heteropolytungstate complexes and their LB films were discussed. The results of excitation spectra indicate that the energy could be effectively transferred from ligands to the Eu3+ ions in the LB films and the luminescence efficiency could be greatly increased. The results of luminescence spectra indicate that the formations of hybrid organic-inorganic LB films have a great effect on the luminescence of europium-substituted heteropolytungstate. The lifetime shortening was observed in LB films.

层次分析法在江河源区高寒草地退化研究中的应用

以江河源区退化高寒草甸为对象,利用层次分析法,探讨了高寒草地的退化原因和恢复治理措施的有效性.结果表明:长期超载过牧和暖干化气候是导致高寒草甸退化的主导因子,贡献率为65.99%;伴随草地初始退化出现的鼠虫和毒杂草泛滥危害是加速高寒草甸退化的重要因子,贡献率为15.03%;人类不合理干扰造成的高寒草甸退化也不应忽视,贡献率为9.64%.各个恢复治理措施组合权重的分配格局相对均衡,其中围栏封育和划区轮牧(E2)与控制放牧强度(E1),效益较好,组合权重达0.3007.层次分析法可为草原管理,防止草地退化、恢复治理退化草地、优化利用草地资源提供定量依据.

基于土地利用/覆被分类系统估算碳储量的差异--以海南岛森林为例

土地利用/覆被分类系统是碳蓄积研究的依据,然而各种碳蓄积研究所采用的土地利用/覆被分类系统不尽相同.根据1993年海南林业资源二类调查资料,我们按照USGS土地利用/覆被、LCCS土地覆被和中国科学院土地资源三种分类系统所定义的类别进行分类并计算了各自的碳储量和碳密度,为碳储量的进一步精确估算和土地覆被分类系统研制提供重要的科学依据.结果发现,(1)不同的土地利用/覆被分类系统所对应的总碳储量以及平均碳密度都有了明显的差别.林业调查资料的植被分类、FAO土地覆被分类系统(LCCS)、USGS土地利用/土地覆被分类系统以及我国学者常用的中国科学院土地资源分类系统的碳蓄积量(Tg C)分别是28.98、28.71、21.04和21.04;碳密度(t C/ha)分别是31.24、30.95、22.68和22.68.(2)土地利用分类系统和土地覆被分类系统之间的结果具有较大差异,其碳储量相差7.67～7.94TgC,碳密度则相差8.27～8.56t C/ha;差距在26.47%～37.74%之间.与其他学者研究结果比较发现,土地利用/覆被分类系统造成的碳蓄积差异的变化方向是不定的,取决于具体的分类系统和材积-生物量函数.不同土地利用/覆被分类系统对于植被划分的不同,导致了材积-生物量回归方程和类别面积的差异是造成碳蓄积和碳密度估算差异的根本原因.目前常用的土地利用/覆被分类系统在估算碳蓄积中存在一定问题,不适合于高精度的碳蓄积计算.体现地表植被生物量差异、植被叶型和外貌特征、种类及树龄差异等内涵的土地利用/覆被分类系统利于陆地碳循环研究的深化.

Applications of outsourcing theory to collaborative purchasing and licensing

Urquhart, C. (2003). Applications of outsourcing theory to collaborative purchasing and licensing. VINE: The Journal of Information and Knowledge Management Systems, 32(4), 63-70.

Online Publizieren - auch in der Erziehungswissenschaft?!

Vor- und Nachteile im Vergleich von herkömmlichem zu elektronischem Publizieren werden erläutert. Mit Bezug auf eine DFG-Studie zum "Publikations- und Rezeptionsverhalten unter besonderer Berücksichtigung von Open Access" wird die Situation speziell in der Erziehungswissenschaft reflektiert und dabei besonders auf das Projekt "Fachportal Pädagogik" eingegangen, das u.a. Qualitätssicherung und Langzeitverfügbarkeit von elektronisch vorliegender erziehungswissenschaftlicher Fachinformation zum Ziel hat. (DIPF/pr)