羟喜树碱结合肽的研究

酯化脱水法制备生物素化羟喜树碱,使用Resourse 15反相柱纯化,液质联用分析确证。磺酰罗丹明B染色法鉴定生物素化羟喜树碱的抗癌活性。采用噬菌体展示技术筛选得到14条羟喜树碱结合肽。构建并优化了羟喜树碱结构模型。构建并通过分子动力学优化了羟喜树碱结合肽结构模型。使用分子对接验证并分析了羟喜树碱结合肽与羟喜树碱的结合作用。     

生物技术在喜树碱研究中的应用

喜树碱是从我国特有植物喜树中分离到的一种具有抗癌活性的萜类吲哚生物碱,具有重要的利用和研究价值.本文通过对喜树碱资源的现状及生物技术在喜树碱研究中的应用进行综述.指出喜树碱及其衍生物在植物体内含量甚微,远远不能满足市场的需要,阐明应用生物技术提高喜树碱含量是目前极其有效的研究手段和方法,同时对利用生物技术大量生产喜树碱的研究方向进行了展望.     

通过组织培养筛选高含量喜树碱细胞系

测定不同生长期喜树苗各器官中喜树碱的含量。其中新生叶和根中的喜树碱的含量较高,然而,喜树碱的含量随叶和枝条生长期的延长而逐渐下降。以喜树碱高含量的幼叶为材料,进行了愈伤组织的诱导和培养,并通过优良细胞系的筛选,使愈伤组织中喜树碱的含量提高到0.02%。     

接种时期对丛枝菌根喜树幼苗喜树碱含量的影响

喜树(Camptotheca acuminata)是我国特有的多年生亚热带落叶阔叶树种, 因其次生代谢产物喜树碱具有良好的抗肿瘤活性而受到人们的广泛关注。通过温室盆栽接种试验, 观察了喜树幼苗不同生长时期接种蜜色无梗囊霉(Acaulospora mellea)和根内球囊霉(Glomus intraradices)对喜树幼苗喜树碱积累的影响。结果表明接种两种丛枝菌根真菌均促进了喜树幼苗喜树碱的积累, 表现为喜树碱产量(单株幼苗所含的喜树碱量, 喜树碱含量与幼苗生物量的乘积)的显著提高。进一步分析发现, 接种丛枝菌根真菌导致幼喜树苗喜树碱产量的提高, 早期(幼苗出土20天)接种主要是源于喜树碱含量的提高, 特别是叶片喜树碱含量的提高, 而晚期(幼苗出土60天)接种则主要是源于幼苗生物量的增加。     

喜树内生菌与喜树碱的关系

通过对喜树幼苗中喜树碱含量的分析,发现不同生长期、不同器官中喜树碱的含量不同,幼叶和根中喜树碱的含量较高。虽然喜树中含有对真核细胞具有毒性作用的喜树碱,但仍有12种内生菌从喜树的不同器官中分离出来。内生菌对喜树碱的敏感性实验表明,10μg／mL喜树碱对2种内生菌的生长几乎没有抑制作用,即是100μg／mL浓度的喜树碱对它们的生长抑制也是有限的。     

喜树种子萌发和幼苗发育过程中喜树碱含量的变化

在喜树种子萌发过程中 ,胚乳中喜树碱含量始终最高 ,但呈降低趋势 ;种皮中喜树碱含量较低 ,呈波动型上升 ;子叶和胚轴中喜树碱含量变化不明显。种子萌发后 ,随着幼苗的发育 ,子叶中喜树碱含量逐渐升高 ,出现最大值后迅速下降 ,胚轴、根和真叶中喜树碱含量持续降低 ,幼苗发育到一定时间后趋于稳定     

光强对喜树幼苗叶片次生代谢产物喜树碱的影响

喜树碱是我国特有树种——喜树中所含的重要次生代谢产物 ,在人工控制条件下观察了光强对喜树幼苗叶片喜树碱含量的影响。喜树幼苗叶片的喜树碱含量随着遮荫程度的增加 (光照强度降低 )而增加 ,但严重遮荫的 (光强为全光照的 2 0 % )在处理后期 (75 d)喜树碱含量降低。叶片的喜树碱产量 (喜树碱含量与叶片生物量乘积 )在处理初期 (30 d)随光强减弱而缓慢地略有增加 ,处理后期 (45 d以后 )随光强的减弱而有明显增加 ,但光强低于全光照的 6 0 %以后喜树碱产量迅速下降。喜树碱的增加可能是喜树幼苗通过次生代谢过程对不良环境 (遮荫 )的一种适应性反应     

不同种源喜树幼枝中喜树碱的含量

通过HPLC测定了喜树(Camptotheca acuminata)不同器官及不同种源幼枝中喜树碱的含量.结果表明,喜树碱含量在叶、种子和幼枝(幼叶和幼茎)中较高,木质部中较少,髓中最低.不同种源的幼枝中,来自成都种源喜树的喜树碱含量最高.通过比较,两年生喜树各器官中喜树碱含量普遍比一年生高,幼枝中顶枝的喜树碱含量比侧枝高.     

不同种源喜树幼枝中喜树碱的含量

通过HPLC测定了喜树(Camptotheca acuminata)不同器官及不同种源幼枝中喜树碱的含量。结果表明, 喜树碱含量在叶、种子和幼枝(幼叶和幼茎)中较高, 木质部中较少, 髓中最低。不同种源的幼枝中, 来自成都种源喜树的喜树碱含量最高。通过比较, 两年生喜树各器官中喜树碱含量普遍比一年生高, 幼枝中顶枝的喜树碱含量比侧枝高。     

Cu2+对喜树愈伤细胞中喜树碱合成的影响

喜树碱是一种从木本植物喜树(Camptothecaacuminata)中分离得到的抗癌活性物质,通过细胞培养合成喜树碱是喜树碱生产的一条重要途径。研究Cu~(2 )对喜树愈伤细胞培养中喜树碱积累的影响,结果表明,在B5培养基中添加0.008mg/mLCuCl2时,对喜树愈伤细胞的生长没有明显影响,但是对喜树愈伤细胞合成喜树碱的促进作用最强,喜树碱含量比未诱导前增加了约30倍。Cu~(2 )阻止培养细胞后期过氧化物酶活力的下降,并抑制花青素的生成。与黑暗培养相比,光照条件下添加Cu~(2 )更利于喜树愈伤细胞诱导合成喜树碱。     

天然色素的超声提取研究

本文主要研究利用超声波提取叶绿素。并且对超声提取法和单纯浸泡法作了比较,同时,分析了叶绿素提取效率对时间的依赖性。实验结果显示,用超声来提取绿色植物中的叶绿素,可以增大提取率,缩短提取时间。     

Comparison of in vitro assays of cellular toxicity in the human hepatic cell line HepG2

Cytotoxicity testing allows determining whether a compound or extract contains significant quantities of biologically harmful chemicals. Cytotoxicity test methods are useful for screening because they serve to separate toxic from nontoxic materials, providing predictive evidence of compound safety. However, a wide range of assays measuring different aspects of cell death is available in the market, but it is difficult to determine which one(s) to use when evaluating a selection of compounds. The objective of this study was to compare different commercially available in vitro assays for cytotoxicity in HepG2 cells according to its sensitivity, reproducibility, simplicity, cost, and speed. The assays evaluated included Alamar Blue for the measurement of mitochondrial activity, ATPlite and ViaLight for the determination of cellular adenosine triphosphate (ATP), ToxiLight as an indicator of cellular necrosis, and Caspase-3 Fluorometric Assay, Apo-ONE Caspase-3/7 Homogeneous Assay, and Caspase-Glo for the determination of caspase-3/7 activity. All assays were performed using 4 compounds of previously reported cytotoxic activity: DMSO, butyric acid, carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP), and camptothecine. Overall, it was concluded that the best way to evaluate the potential cytotoxicity of a compound is to employ a battery of assays that focus on different aspects of cell death. In this case, the focus has been on ATP levels, cell necrosis, and capsase-3/7 activation. Many other kits are commercially available in the market for these and other aspects of necrosis and/or apoptosis. However, the use of ViaLight Plus, ToxiLight, and Caspase-3 Fluorometric Assay resulted in the most useful combination when working with HepG2 cells.     

快速提取肠道微生物基因组DNA的方法

目的:肠道微生物的研究日益成为热点,如何获取高质量、较完整的肠道菌群基因组DNA是肠道微生物研究中的关键。本文通过对酚/氯仿法提取总DNA过程进行考察和优化,建立一种简便酚/氯仿抽提法。方法:考察和优化酚/氯仿法提取总DNA的过程,并根据DNA产量、纯度以及ERIC-PCR及16S rNDA-RFLP所反映的微生物群落结构特性的指标,并与QIAamp?DNA Stool Mini Kit提取的进行比较,评价了所建立的快速提取方法。结果:用简便酚/氯仿法得到基本完整的基因组DNA,ERIC-PCR和16S rDNA-RFLP结果与QIAamp?DNA Stool Mini Kit法基本相同。结论:该方法快速并成本低,适合肠道微生物研究中总DNA提取,尤其适合处理大批量的样品。     

短尾猴陈旧粪便中DNA的提取

分子粪便学（Molecular scatology）是一门将传统粪便分析方法与分子生物学技术相结合,以动物粪便为实验材料进行多领域研究的学科（魏辅等,2001）。虽然该方法已在野生濒危动物保护遗传学和分子生态学研究中发挥了很大作用（Kohnand Wayne,1997）,但目前大多数分子粪便学研究中使用的材料是新鲜粪便,从保存时间很长的陈旧粪便中很难提取到高质量的DNA用于PCR扩增以及序列分析,严重制约了分子粪便学的广泛应用（Wasser et al．,1997;Constable et al．,2001;Murphy et al．．2002）。     

一种经济高效提取实蝇基因组DNA的方法

单头实蝇高质量基因组DNA的获得为实蝇分子生态学研究奠定了重要基础。本文提出一种经济高效的实蝇基因组DNA提取方法,该方法广泛适用于不同虫态、不同保存条件的实蝇标本,与传统的CTAB法和SDS法相比操作简单、耗时短,得率高。     

THE POPULATION OF A LARGE MOUND OF NASUTITERMES EXITIOSUS (HILL) (ISOPTERA: TERMITIDAE)

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More than 2.5 million termites, weighing 11.05 kg, were obtained from a mound colony of Nasutitermes exitiosus (Hill). Because of the unusually large size of the colony examined, and the favourable conditions that were experienced for extracting the termites, it is thought that this figure is close to the upper limit of nest population attained by this termite.     

Abacus: a computational tool for extracting and pre-processing spectral count data for label-free quantitative proteomic analysis

We describe Abacus, a computational tool for extracting spectral counts from MS/MS data sets. The program aggregates data from multiple experiments, adjusts spectral counts to accurately account for peptides shared across multiple proteins, and performs common normalization steps. It can also output the spectral count data at the gene level, thus simplifying the integration and comparison between gene and protein expression data. Abacus is compatible with the widely used Trans-Proteomic Pipeline suite of tools and comes with a graphical user interface making it easy to interact with the program. The main aim of Abacus is to streamline the analysis of spectral count data by providing an automated, easy to use solution for extracting this information from proteomic data sets for subsequent, more sophisticated statistical analysis.     

An Electrode Design Rule for Organic Photovoltaics Elucidated Using Molecular Nanolayers

Silane nanolayers deposited from the vapor phase onto indium‐tin oxide (ITO) coated glass are shown to be an effective means of tuning the work function and stabilizing the surface of this complex ternary oxide. Using this approach a pair of model hole‐extracting electrodes have been developed to investigate how the performance of bi‐layer organic photovoltaics is impacted by built‐in positive space charge in the critical region close to the hole‐extracting electrode. The magnitude and spatial distribution of positive space charge resulting from ground‐state electron transfer from the donor layer to the ITO electrode upon contact formation, is derived from direct measurements of the interfacial energetics using the Kelvin probe technique. This judiciously designed experiment shows that it is unnecessary to engineer the work function of the hole‐extracting electrode to match the ionization potential of the donor layer, rather only to ensure that the former exceeds the latter, thus simplifying an important aspect of device design. In addition, it is shown that silane nanolayers at the ITO electrode surface are remarkably effective at retarding device degradation under continuous illumination.     

双指标优选肠安颗粒中有机酸提取工艺条件(I)

以总有机酸和绿原酸的提取率双指标作为提取条件考核对象,来探讨肠安颗粒中所含有机酸成分的中药材的最佳提取工艺。采用L9(34)正交设计,考察提取溶媒所需加水量、浸泡时间、煎煮时间、煎煮次数四个因素,选择进行3个水平试验。得出结论:以加10倍量的水(第一次煎煮多加1.5倍量),浸泡1 h,煎煮2次,每次1h为最佳提取工艺条件,亦即以A2B2C2D2组合为合理。     

一种从鸟类剥制标本提取DNA的改进方法

应用非损伤性取样的方法,收集鸟类剥制标本的皮肤组织和羽毛,用无水乙醇、浸泡液预处理的方法抽提DNA,结果两者都可提取DNA供PCR扩增。将PCR产物经序列测定和比对分析,证明提取的DNA为目的DNA,表明本试验方法可行。鸟类剥制标本的皮肤组织和羽毛可以作为研究种群遗传学的资源。