改良比色法在神经致幻型毒菌活性色胺类物质检测中的应用

改良了神经致幻型毒菌活性色胺类物质的比色检测方法。利用白灵菇子实体的稀醋酸提取液替代水作为空白对照,检测结果更为客观、准确;筛选到了不使用硫酸的显色剂配方,降低了操作过程中的危险性。探讨了改良的比色法在毒菌活性色胺类物质半定量和定量检测中的应用。结果表明,该方法可以用于毒菌总活性色胺类物质的半定量检测;结合薄层层析法,还可以用于特定毒素的定量检测。     

Novel efficacious microRNA-30c analogs reduce apolipoprotein B secretion in human hepatoma and primary hepatocyte cells

High plasma lipid levels have been demonstrated to increase cardiovascular disease risk. Despite advances in treatments to decrease plasma lipids, additional therapeutics are still needed because many people are intolerant or nonresponsive to these therapies. We previously showed that increasing cellular levels of microRNA-30c (miR-30c) using viral vectors or liposomes reduces plasma lipids and atherosclerosis. In this study, we aimed to synthesize potent miR-30c analogs that can be delivered to hepatoma cells without the aid of viral vectors and lipid emulsions. We hypothesized that modification of the passenger strand of miR-30c would increase the stability of miR-30c and augment its delivery to liver cells. Here, we report the successful synthesis of a series of miR-30c analogs by using different chemically modified nucleosides. In these analogs, we left the active sense strand untouched so that its biological activity remained unaltered, and we modified the passenger strand of miR-30c to enhance the stability and uptake of miR-30c by hepatoma cells through phosphorothiorate linkages and the addition of GalNAc. We show that these analogs significantly reduced apolipoprotein B secretion in Huh-7 human hepatoma cells and human primary hepatocytes without affecting apolipoprotein A1 secretion and cellular lipid levels. Our results provide a proof of concept that the passenger strand of miR-30c can be modified to increase its stability and delivery to cells while retaining the potency of the sense strand. We anticipate these miR-30c analogs will be useful in the development of more efficacious analogs for the treatment of hyperlipidemias and cardiovascular diseases.     

Ecological risk assessment of transgenic plant releases: an Austrian perspective

Some prerequisites for ecological risk assessment of transgenic plant releases are examined, with the aim of identifying research needs in Austria. Austria harbours high habitat diversity, extending from the Alps to the Pannonian continental lowlands. The Pannonian flora includes potential cross-breeding partners of several crops, which do not occur in western Europe. The border zones of major biogeographical regions contain high biodiversity, both in terms of species and habitat diversity; whether the genetic variability of widespread plant species is also increased in these areas requires further investigation. Especially in Alpine regions, transgenic grasses might eventually cause profound changes in community structure. Ecological risk assessment of transgenic crop releases should not only consider adverse effects on non-target species and ecosystems, but also their likely impact on the agroecosystems.     

嗜卷书虱高CO_2抗性品系的选育及其适合度研究(英文)

室内恒温条件下以人工饲料饲养的嗜卷书虱 Ｌｉｐｏｓｃｅｌｉｓ ｂｏｓｔｒｙｃｈｏｐｈｉｌａ Ｂａｄｏｎｎｅｌ成虫,分别在３５％和５５％ＣＯ_２。（２１％Ｏ_２,Ｎ_２作为平衡气体使用）组配的气调环境中以７０％的选择压力处理,以选育其抗高ＣＯ_２气调性。选育至３０代获得抗性品系ＨＣＣ_１和ＨＣＣ_２,以ＬＴ_５０为标准,其抗性倍数分别达４．６和５．３倍。整个选育过程中,气调暴露时间对数值与死亡率机率值间的回归直线基本平行,且斜率值均低于敏感基线的斜率值,这表明嗜卷书虱对高ＣＯ_２抗性发展的基因潜能至第３０代仍未耗尽。两个抗性品系的抗性均不太稳定,去除选择压力后抗性显著下降,且两抗性品系均具有繁殖不利性即适合度缺陷。以净增值率为指标衡量,ＨＣＣ_１和ＨＣＣ_２相对于敏感品系分别具有０．５２和０．４５的适合度。     

Assessing the impacts of genetically modified microorganisms

The progression towards greater industrial sustainability involves the analysis of biotechnology as a means of achieving clean or cleaner products and processes. Because living systems manage their chemistry more efficiently than man-made factories, and their wastes tend to be recyclable and biodegradable, they can be expected to be more environmentally clean. Industry has begun to use enzymes instead of traditional catalysts in many industrial production processes. The future holds obstacles as well as opportunities for biotechnological applications. A greater ability to manipulate biological materials and processes will have significant impact on manufacturing industries. A growing proportion of biotechnologyderived processes and products is based on the use of genetically modified microorganisms. This extends the analysis from the aspect of cleanliness to the aspect of safety.     

Fate of pBR322 DNA in a wastewater matrix

Recombinant organisms used in biopharmaceutical production processes are destroyed prior to environmental release into a private or municipal wastewater treatment system. However, concern over the fate of recombinant DNA used in these processes may adversely affect product regulatory approval. This study examined the fate of DNA from the plasmid pBR322 in an activated sludge-derived matrix. DNA suitable for PCR amplification was extracted from the activated sludge matrix and a 1042-bp fragment from pBR322 rapidly decreased in concentration from 0 to 2 h after it was spiked into the activated sludge matrix at an initial DNA concentration of 25 ng ml⁻¹. While some evidence of the 1042-bp fragment was observed at 4 h, no evidence of amplified DNA was observed at 6 h. Plasmid DNA in buffer that served as a positive control exhibited no significant reduction in concentration over time. The intensity of each DNA band over the first 4 h was analyzed. A linear regression of the natural log transformation of these results yielded a mean first-order rate constant of 3.55 h⁻¹ and half-life of 0.2 h. This study demonstrated that recombinant DNA released from industrial processes into wastewater treatment systems should be rapidly degraded. Received 14 August 1998/ Accepted in revised form 19 February 1999     

氧化修饰低密度脂蛋白与动脉粥样硬化

动脉粥样硬化的发生发展与低密度脂蛋白受到氧化修饰有关。本文从以下四个方面对本室的工作进行了综述：（１）动脉粥样硬化机体受到脂质过氧化损伤;（２）Ｏｘ－ＬＤＬ对内皮细胞、平滑肌细胞和巨噬细胞的毒性效应;（３）Ｏｘ－ＬＤＬ和ＭＤＡ－ＬＤＬ的比较及与Ｏｘ－ＬＤＬ和ＭＤＡ－ＬＤＬ结合的清道夫受体的特征;（４）不同方法对ＬＤＬ氧化修饰的比较和以ＬＤＬ氧化修饰为模型对某些物质的抗氧化修饰研究。研究结果为动脉粥     

Elucidating the Targets of Antileukemic Agents: Molecular Mechanisms of Mercaptopurine Action

Mercaptopurine and thioguanine are anticancer and immunosuppresive agents that exert their primary cytotoxic effects via incorporation of deoxythioguanosine into DNA. Elucidation of molecular mechanisms underlying the sensitivity/resistance to thiopurine drugs is essential to further improving the therapy for leukemia. Inherited deficiency in thiopurine S-methyltransferase activity determines idiosyncratic reactions to thiopurines. Isolation and cloning of mutant alleles from humans with thiopurine S-methyltransferase deficiency has helped to develop PCR-based genotyping assays for this disorder. Incorporation of deoxythioguanosine into DNA substantially alters DNA–protein interactions at several steps of DNA replication. Importantly, it prevents RNA hydrolysis by RNase H in the DNA–RNA heteroduplex, and decreases the thermal stability of the DNA duplexes.     

3-Thiopropionic acid as a highly versatile multidetachable thioester resin linker

This paper describes a practical new use of3-mercaptopropionic acid as a highly versatilemultidetachable linker for solid-phase synthesis. Ourapproach is based on the stability of thealkylthioester functionality to optimized Boc-SPPSprotocols and HF treatment, as well as on the mildactivation of the thioester functionality towardnucleophilic or reductive displacement. This allowsseveral C-terminal modifications to be introduced intoa synthetic molecule during the cleavage step. We haveshown that unprotected peptides can be efficientlycleaved from a propyl thioester-polyethyleneglycol-poly-(N,N-dimethylacrylamide) copolymerresin using a great variety of nucleophiles to givethe corresponding C-terminally modified peptides(esters, thioesters, carboxylic acids, thioacids,amides, hydroxamic acids, hydrazides, alcohols). Thenucleophilic cleavage reaction is both rapid andexceptionally clean in all the cases tested.     

A Modified T-test Feature Selection Method and Its Application on the HapMap Genotype Data

Single nucleotide polymorphisms (SNPs) are genetic variations that determine the differences between any two unrelated individuals. Various population groups can be distinguished from each other using SNPs. For instance, the HapMap dataset has four population groups with about ten million SNPs. For more insights on human evolution, ethnic variation, and population assignment, we propose to find out which SNPs are significant in determining the population groups and then to classify different populations using these relevant SNPs as input features. In this study, we developed a modified t-test ranking measure and applied it to the HapMap genotype data. Firstly, we rank all SNPs in comparison with other feature importance measures including F-statistics and the informativeness for assignment. Secondly, we select different numbers of the most highly ranked SNPs as the input to a classifier, such as the support vector machine, so as to find the best feature subset corresponding to the best classification accuracy. Experimental results showed that the proposed method is very effective in finding SNPs that are significant in determining the population groups, with reduced computational burden and better classification accuracy.