线粒体DNA及其提取方法

线粒体是存在于绝大多数真核细胞内的一种基本的重要的细胞器,其具有相对独立的遗传系统。线粒体基因在真核生物具有高保守性,线粒体DNA(mtDNA)已被广泛应用于发病机理、临床诊断、遗传变异、生物进化等多方面的研究。1981年,Anderson用氯化铯密度梯度分离得到线粒体DNA(mtDNA),进行了全序列分析。此后,mtDNA的研究日益得到重视。已有的mtDNA提取方法概括起来可分为密度梯度离心法、酶消化法、柱层析法、氯化铯超速离心法、碱变性法和改进高盐沉淀法等,通过对以上方法的比较,发现改进高盐沉淀法具有简便、经济、易重复等优点。     

红树植物秋茄叶片双向电泳技术体系的建立及优化

对适用于秋茄(Kandelia candel)叶片蛋白质组学研究的双向电泳技术体系进行了优化.结果表明,采用酚抽提法提取的蛋白质浓度较低,约1.7 μg μL-1,SDS-PAGE电泳后几乎无条带;而采用改良TCA -丙酮沉淀法可显著提高提取液中蛋白质的含量,可达12.4 μgμL-1.秋茄叶片蛋白质主要分布在pH4～...     

Removal of nonionic surfactants from wastewater using a constructed wetland

Removal of nonionic surfactants from municipal wastewater using a constructed wetland with a horizontal subsurface flow was studied in 2009 and 2010. Extraction spectrophotometry with 3′,3″,5′,5″‐tetrabromophenolphthalein ethyl ester and KCl served to determine the analyte concentrations. Triton^® X‐100 was used as a standard to express the nonionic‐surfactant concentrations. Anionic and cationic surfactants were shown not to interfere during the determination. Nonionic surfactants were degraded (to products undeterminable by the method) with a high average efficiency that reached 98.1% in 2009 and 99.1% in 2010, respectively. The average concentration of nonionic surfactants at the inflow was 0.978 mg/l, while it was close to the limit of quantification at the outflow (0.014 mg/l). A significant fraction of nonionic surfactants (38.7%) was already degraded during the pretreatment, and only 14.0% of the nonionic surfactants remained in the interstitial H₂O taken in the vegetation bed at a distance of 1 m from the inflow zone at a 50‐cm depth. Nonionic surfactants were degraded both under aerobic and anaerobic conditions.     

Rapid quantification and taxonomic classification of environmental DNA from both prokaryotic and eukaryotic origins using a microarray

A microarray has been designed using 62,358 probes matched to both prokaryotic and eukaryotic small-subunit ribosomal RNA genes. The array categorized environmental DNA to specific phylogenetic clusters in under 9 h. To a background of DNA generated from natural outdoor aerosols, known quantities of rRNA gene copies from distinct organisms were added producing corresponding hybridization intensity scores that correlated well with their concentrations (r=0.917). Reproducible differences in microbial community composition were observed by altering the genomic DNA extraction method. Notably, gentle extractions produced peak intensities for Mycoplasmatales and Burkholderiales, whereas a vigorous disruption produced peak intensities for Vibrionales, Clostridiales, and Bacillales.     

Seaweed processing using industrial single-mode cavity microwave heating: a preliminary investigation

A single-cavity microwave heating system has been designed and fabricated for microwave-assisted extraction of carrageenans from seaweed. The system comprises a single mode (TE101) waveguide fitted with power and temperature controls, together with a continuous-flow-recycle reactor operating at atmospheric pressure. The system has been tested by extraction of E. cottonii and E. spinosum in aqueous organic solvents. Even without purification, the extraction products were found to have virtually identical FTIR and 13C and 1H NMR spectra to the reference samples of kappa- and iota-carrageenan, respectively. The principal advantages of the microwave system are substantial reduction of extraction time and low consumption of organic solvents.     

Tracking variations in nicotinamide cofactors extracted from cultured cells using capillary electrophoresis with multiphoton excitation of fluorescence

Nicotinamide cofactors play numerous roles in cellular metabolic and biosynthetic reactions and intracellular signaling events. Recently, nicotinamide cofactors have been implicated in the function of cellular biological clocks. To gain insight into the possible roles of nicotinamide cofactors in complex time-related events, we have developed a rapid and sensitive method for extraction of NAD(P)(H) from cultured cells, separation of analytes by capillary electrophoresis, and detection by multiphoton excitation of fluorescence. Extraction and quantitation steps have been systematically characterized for optimal pH, detergent, temperature, sonication, filtration, efficiency, accuracy, and reproducibility. The method is suitable for extractions at 2- to 3-h intervals over 1 day or more or as frequently as every hour for shorter durations. Natively fluorescent NAD(P)H are assayed directly, and nonfluorescent NAD(P) are enzymatically reduced to their fluorescent counterparts before analysis. The method yields accurate values for cellular NADP, NADPH, and total NAD(H) levels and relative information on cellular NADH concentration; modification of the procedure allows full quantitation of all relevant species. We conclude that these assays are more suitable than any yet published for tracking variations in nicotinamide cofactor levels over periods of 1 day or more.     

Potato tuber proteomics: comparison of two complementary extraction methods designed for 2-DE of acidic proteins

Two protein extraction procedures were tested in order to remove interfering compounds prior to 2-DE of potato tubers. These methods using SDS lysis buffer and phenol-phase extraction were compared regarding the quality of the resulting 2-D gel. While the resolution of SDS extracts on semipreparative gels seems better, both methods lead to similar extraction yields and total number of spots. The procedures are complementary regarding the Mr range of preferentially extracted proteins.     

小麦胚芽蛋白的研究进展

小麦胚芽是面粉加工过程中的副产物,小麦胚芽蛋白具有良好的氮溶解度、起泡性、乳化性以及保水性、氨基酸比例平衡,不仅是饮料、食品以及医疗产品良好的添加剂,而且具有较强的产品开发潜力。对小麦胚芽蛋白的组成成分、理化性质、提取以及麦胚蛋白产品开发利用这四个方面进行简要的介绍,旨在为小麦胚芽蛋白的全面开发利用提供依据。     

Comparative study of alkali- and acidic organic solvent-soluble hemicellulosic polysaccharides from sugarcane bagasse

Two-stage treatments of sugarcane bagasse with mild alkali and acidic 1,4-dioxane were performed. Pretreatment with 1M NaOH aqueous solution at 20, 25, 30, 35, and 40 degrees C for 18 h released 55.5%, 57.3%, 59.1%, 60.9%, and 62.1% of the original hemicelluloses, respectively. Post-treatment of the corresponding alkali-treated residue with 1,4-dioxane-2M HCl (9:1, v/v) at 87 degrees C for 2h, respectively, degraded 11.6%, 11.9%, 11.4%, 10.9%, and 10.6% of hemicelluloses (% dry starting material). It was found that the five alkali-soluble hemicellulosic preparations contained a much higher amounts of xylose (78.0-82.2%) and slightly higher uronic acids (4.8-5.8%), mainly 4-O-methyl-alpha-d-glucopyranosyluronic acid, but were lower in arabinose (9.3-11.7%) and glucose (2.2-4.1%) than those of the corresponding five acidic dioxane-degraded hemicellulosic fractions in which xylose (44.9-46.8%), arabinose (35.9-38.1%), and glucose (13.0-13.7%) were the major sugar constituents. The studies revealed that the five alkali-soluble hemicellulosic preparations were more linear and acidic, and had a large molecular weight (35,200-37,430 g mol(-1)) than those of the hemicellulosic fractions (12,080-13,320 g mol(-1)) degraded during the acidic dioxane post-treatment. This demonstrated that the post-treatment with acidic dioxane under the condition used resulted in substantial degradation of the hemicellulosic polymers. The 10 hemicellulosic samples were further characterized by FT-IR and 1H and 13C NMR spectroscopy, GPC and thermal analysis, and the results are reported.     

Identifying decomposition products in extracts of cellular metabolites

Most methods of analyzing intracellular metabolites require extraction of metabolites from the cells. A concern in these methods is underestimation of metabolite levels due to incomplete extraction. In comparing extraction methods, then, it would seem that the best method for extracting a particular metabolite is the one that gives the largest yield. In extracting Escherichia coli with different methanol:water mixtures, we observed that >or=50% water gave an increased yield of nucleosides and bases compared with 相似文献