短期高温胁迫对高产小麦品系灌浆后期旗叶光系统Ⅱ功能的影响

以叶绿素快相荧光动力学曲线(OJIP)为探针,探讨了高温胁迫对高产小麦品系01-35灌浆后期光系统Ⅱ（PSⅡ）功能的影响.结果表明,在37 ℃～43 ℃范围内,随温度升高Q_A还原程度和还原速率增大,至43 ℃时分别比室温下增加了23.89%和24.09%,表明Q_A→Q_B的电子传递受到抑制;43 ℃时PSⅡ的电子受体库降至室温下的47.4%,表明高温胁迫伤害了PSⅡ受体库;而PSⅡ供体侧未受到影响.当温度达到46 ℃时,Q_A还原程度和还原速率分别比室温下增加了13.95%和20.48%,但比43 ℃时显著下降,而PSⅡ电子受体库与43 ℃时相比无显著变化,表明46 ℃时PSⅡ供体侧受到伤害.与对照品种鲁麦14相比,高温胁迫下高产小麦的捕光色素复合体仍能捕获较多的光能,而且将捕获的光能更多的用于电子传递,表明高产小麦的捕光色素复合体及电子传递体耐受高温的能力较强,能够维持较高的电子传递能力.     

A method for rapid abundance estimation of semiplanktonic meiofauna

Many meiofaunal copepods and plathelminths enter the tidal waters at night thus exhibiting a life-style intermediate between benthic and planktonic. At the same time, ostracods may leave their interstitial dwelling and move across the sediment surface. In laboratory experiments, the percentage of plathelminth populations emerging from the sediment varied with the species, temperature, light conditions, and the dimensions of the sediment cores studied, but not with tidal level, season, ambient density of conspecifics, or the sediment composition. Therefore, the swimming activity may be utilised for extraction of semiplanktonic meiofauna provided that the extraction procedure is standardised with respect to temperature, light and core size. For free-living plathelminths from the Wadden Sea intertidal a robust standard procedure is as follows: sediment cores 1.6 cm in diameter (2 cm² surface area) and 3 cm deep are fitted into cylindrical containers and submerged into aquaria containing filtered seawater (ambient salinity, room temperature, darkness) for 24 h. The sediment containers are then removed and the aquarian water filtered through appropriate meshes; the residue contains the emergent faunal component. For plathelminths, this procedure reduces sorting time by some 90% compared with the standard shaking–decantation method and thus makes it possible to process a high number of samples in a short time. Similar procedures may be developed for copepods and epibenthic ostracods. Received in revised form: 28 August 2000 Electronic Publication     

超滤法提取裂褶菌胞外多糖几个主要参数的研究

对超滤法提取裂褶菌胞外多糖进行了研究,采用“二次回归旋转正交组合设计”得出超滤法提取裂褶菌胞外多糖的最优条件为:压力0.11MPa,温度55.20℃,pH4.01。在上述条件下超滤速度达31.92ml/min,制得的裂褶菌胞外多糖是以D-葡聚糖为主的混合多糖,其纯度为75.13%,收率可达82.06%。     

C群脑膜炎球菌多糖纯化方法的改进

将C群脑膜炎球菌粗多糖的纯化改进为用1:1容量冷酚提取的生产工艺。结果表明,改进后的方法去除蛋白质效果同样能够达到《中国药典》2005版(三部)的要求,总体结果优于改进前。同时能扩大处理量而降低了生产成本,适合规模化生产。     

Extraction of caesium from mosses and incorporation into an oxalate crystalline lattice

The ratios of stable and radioactive isotopes in the environment are not constant and their effects on living organisms are not the same. Whilst radionuclides can be monitored by measuring their radioactivity levels, it is also important to determine the stable isotopes. The method described in this paper represents a simple and cheap process by which to extract caesium from moss, without significant destruction of the plant, and to incorporate the isolated caesium into a water-soluble crystal. Ammonium oxalate and phosphoric acid are water-soluble substances at 5% concentration but, when the solutions are combined, crystallisation occurs. Crystals were estimated to contain 68.30% O, 20.98% C, 4.68% H, 6.04% N and less than 0.01% P, corresponding to NH4HC2O4 x H2C2O4 x 2H2O (C4H11NO10). The crystal mass did not vary with the species of moss, although the effectiveness of caesium extraction did. Typically, 73.0 +/- 6.1% of the solubilised caesium was entrapped within the crystals.     

Extraction and characterization of hemicelluloses from flax shives by different methods

Hemicelluloses were extracted from flax shives using pressurized low-polarity water (PLPW), pressurized aqueous ethanol (PAE), microwave-assisted water (MW-Water) or aqueous ethanol (MW-EtOH), and precipitated with ethanol. Hemicelluloses still remaining in solution were further separated using ultrafiltration. All samples were characterized with chemical analysis, ion-moderated partition chromatography (IMP), size exclusion chromatography (SEC), and Fourier transform infrared (FT-IR) spectroscopy. PLPW, PAE, MW-Water and MW-EtOH extracted 90, 80, 18, and 40% of the total hemicelluloses, respectively. The molecular weight of the ethanol-precipitated hemicelluloses ranged from approximately 11,000 to 40,000 Da and the ethanol-soluble low-molecular weight hemicelluloses were about 1700 Da. High-molecular weight hemicellulose isolated from PAE extracts contained 23% lignin, while that from the PLPW extracts contained 5% lignin. Low-molecular weight hemicelluloses separated by ultrafiltration from PLPW and PAE extracts contained similar amounts of lignin (20%). However, the yield of low-molecular weight hemicelluloses from PLPW was higher (15%) compared to that from PAE (6%). The FT-IR results revealed the specific band maximum at 1220 cm⁻¹ and the bands between 1175 and 1000 cm⁻¹ which are typical of xylans.     

真菌多糖水提及化学辅助提取方法研究进展

真菌多糖具有抗肿瘤、抗衰老、免疫调节等多种功效, 有较高的食、药用和商业价值。本文通过对实例的总结, 介绍热水浸提法、稀酸提取法、碱提取法、酶消化提取法等真菌多糖提取技术。通过比较阐述其优缺点、影响因素和适用范围, 为类似试验提供建议。     

一种改良的CTAB法提取产多糖真菌DNA

真菌胞外多糖由于其高吸附高粘稠特点,是困扰从胞外多糖产生菌分离高纯度DNA的难点之一。本文以生产硬葡聚糖的齐整小核菌生产菌为代表,采用改良的CTAB法获得了高质量的基因组DNA。通过分层隔离等培养方法的优化降低硬葡聚糖的产生,并在传统CTAB法的基础上,用高浓度的醋酸钾和无水乙醇共同作用初步沉淀多糖,再用CTAB/NaCl溶液再次去除多糖。相比于商业的DNA提取试剂盒和传统的CTAB法,该方法得到的基因组DNA产率大幅提高,纯度较好,可充分排除胞外多糖的干扰,为各典型产胞外多糖的真菌DNA提取提供重要的参考。提取的基因组DNA可用于基因组文库构建、PCR等分子生物学实验。     

中国淡水涡虫RAPD分析条件的优化(简报)

涡虫是动物界最早出现两侧对称、三胚层、营自由生活的扁形动物,也是由水生向陆生过渡的重要类群,因而在动物系统演化中占有重要地位。由于涡虫再生能力极强,因此成为研究细胞分化与去分化     

Simultaneous extraction of several metabolites of energy metabolism and related substances in mammalian cells: optimization using experimental design

As a basis for the development of predictive mathematical models in systems biology and a quantitative understanding of cellular metabolism, reliable experimental data sets of intracellular metabolites are indispensable. A prerequisite for the acquisition of such data is the identification of a suitable sample preparation method. In this work, the extraction procedure for the simultaneous measurement of a wide range of intracellular metabolites from adherent mammalian cells in culture was optimized. A screening of several commonly used extraction protocols with Madin-Darby canine kidney (MDCK) cells found the methanol/chloroform (MeOH/CHCl(3)) and MeOH/Boil methods to be promising candidates for further analysis by anion-exchange chromatography. Both methods were optimized based on experimental design techniques with four response variables: Nucleotide Content, Energy Charge, Fructose 1,6-Bisphosphate content (F16bP), and Absorption at 280 nm. After data evaluation and with the help of desirability functions, an overall optimum for the extraction conditions was found. Using optimal settings, the extraction performances for MDCK and Vero cell cultivations of both methods were compared. Both methods extracted nearly the same absolute amounts of intracellular metabolites, suggesting that these methods are equal. However, recoveries for nucleotide diphosphates were significantly above 100% for both methods. This most likely was due to remaining nucleotide kinase activity during extraction. After combining individual steps of both methods, recoveries close to 100% for all metabolites could be reached. Absolute values of intracellular metabolites extracted with this modified method are comparable to the results of the two previously optimized methods, indicating a good extraction procedure according to the chosen response variables.