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51.
Shama Ahmad Aftab Ahmad Keith B. Neeves Tara Hendry-Hofer Joan E. Loader Carl W. White Livia Veress 《Journal of visualized experiments : JoVE》2014,(87)
Cell cultures are indispensable to develop and study efficacy of therapeutic agents, prior to their use in animal models. We have the unique ability to model well differentiated human airway epithelium and heart muscle cells. This could be an invaluable tool to study the deleterious effects of toxic inhaled chemicals, such as chlorine, that can normally interact with the cell surfaces, and form various byproducts upon reacting with water, and limiting their effects in submerged cultures. Our model using well differentiated human airway epithelial cell cultures at air-liqiuid interface circumvents this limitation as well as provides an opportunity to evaluate critical mechanisms of toxicity of potential poisonous inhaled chemicals. We describe enhanced loss of membrane integrity, caspase release and death upon toxic inhaled chemical such as chlorine exposure. In this article, we propose methods to model chlorine exposure in mammalian heart and airway epithelial cells in culture and simple tests to evaluate its effect on these cell types. 相似文献
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为探明羽裂蟹甲草Cacalia tangutica的杀虫活性及其活性成分, 通过拌糖饲喂法和浸渍法测定了羽裂蟹甲草甲醇提取物对家蝇Musca domestica成虫和白纹伊蚊Aedes albopictus 4龄幼虫的毒杀活性, 并采用色谱分离技术和现代波谱技术对羽裂蟹甲草中的化学成分进行了分离鉴定。结果表明: 该植物不同部位甲醇提取物对家蝇成虫和白纹伊蚊4龄幼虫均具有较高的生物活性。从该植物叶和花甲醇提取物中分离鉴定了豆甾醇、 无羁萜、 7 羟基 8 甲氧基香豆素、 7 羟基香豆素、 7, 8 二羟基香豆素、 瑞香素-8-O-β-D-葡萄糖苷、 槲皮素、 山奈酚和β 胡萝卜苷9个化合物。无羁萜、 槲皮素和山奈酚为首次从该植物中分离得到, 500 μg/g拌糖处理48 h后, 其对家蝇成虫的校正死亡率分别为88.30%, 69.90%和77.04%; 50 μg/mL药液处理72 h后, 其对白纹伊蚊4龄幼虫的校正死亡率分别为88.49%, 72.22%和71.06%; 均与鱼藤酮差异不显著(P<0.05), 表现出良好的杀虫活性。本研究说明羽裂蟹甲草对家蝇和白纹伊蚊具有明显的毒杀活性, 是一种潜在的卫生害虫控制剂。 相似文献
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腈化合物是一类重要的用于合成多种精细化学品的化合物,它们容易制备,并且可以合成多种化合物。传统化学水解方法将腈化合物转化为相应的羧酸或酰胺通常需要高温、强酸、强碱等相对苛刻的条件,腈转化酶(腈水解酶、腈水合酶和酰胺酶)由于其生物催化过程具有高效、高选择性、条件温和等特点,在精细化学品的合成中越来越受到人们的关注。许多腈转化酶已经被开发出来并用于精细化学品的生产。以下介绍了腈转化酶在医药及中间体、农药及中间体、食品与饲料添加剂等精细化学品生产中的应用。随着研究的不断深入,将会有更多的腈转化酶被开发出来并用于精细化学品的生产。 相似文献
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Ralstonia eutropha strain H16 is a Gram-negative non-pathogenic betaproteobacterium ubiquitously found in soils and has been the subject of intensive research for more than 50 years. Due to its remarkable metabolically versatility, it utilizes a broad range of renewable heterotrophic resources. The substrate utilization range can be further extended by metabolic engineering as genetic tools are available. It has become the best studied “Knallgas” bacterium capable of chemolithoautotrophic growth with hydrogen as the electron donor and carbon dioxide as the carbon source. It also serves as a model organism to study the metabolism of poly(β-hydroxybutyrate), a polyester which is accumulated within the cells for storage of both carbon and energy. Thermoplastic and biodegradable properties of this polyhydroxyalkanoate (PHA) have attracted much biotechnical interest as a replacement for fossil resource-based plastics. The first applications of R. eutropha aimed at chemolithoautotrophic production of single cell protein (SCP) for food and feed and the synthesis of various PHAs. The complete annotated genome is available allowing systematic biology approaches together with data provided by available omics studies. Besides PHAs, novel biopolymers of 2-hydroxyalkanoates and polythioesters or cyanophycin as well as chemicals such as alcohols, alkanes, alkenes, and further interesting value added chemicals significantly recently extended the range of products synthesized by R. eutropha. High cell density cultivations can be performed without too much effort and the available repertoire of genetic tools is rapidly growing. Altogether, this qualifies R. eutropha strain H16 to become a production platform strain for a large spectrum of products. 相似文献
59.
Kaizhi Xie Shaohai Yang Peizhi Xu Hui Zhang Shuanhu Tang Fabao Zhang 《Soil & Sediment Contamination》2013,22(5):510-520
We describe the effect on the population of Eubacteria and Archaea species of adding the endocrine-disrupting chemicals (EDCs) nonylphenol (NP) or dibutylphthalate (DBP) to a typical paddy soil. Fluorescence in-situ hybridization was used to discriminate between the two phyla, and denaturing gradient gel electrophoresis (DGGE) of an amplified fragment of the 16S rRNA locus was used to profile the species present. The population of both Eubacteria and Archaea species was reduced by the presence of NP or DBP, and the deleterious effect was greater for the Eubacteria. The DGGE profiles were used to assess the species diversity in the polluted and non-polluted soil samples. This showed that DBP was less damaging than NP50. It was clear that EDCs can significantly affect paddy soil microbial diversity, both with respect to population size and species representation. 相似文献
60.
Cost-Effectiveness Analysis of Chemical Testing for Decision-Support: How to Include Animal Welfare?
Toxicity testing for regulatory purposes raises the question of test selection for a particular endpoint. Given the public's concern for animal welfare, test selection is a multi-objective decision problem that requires balancing information outcome, animal welfare loss, and monetary testing costs. This paper demonstrates the applicability of cost-effectiveness analysis as a decision-support tool for test selection in a regulatory context such as, for example, the new European chemicals legislation (REACH). We distinguish different decision-making perspectives, in particular the regulator's and chemical industry's perspectives, and we discuss how cost-effectiveness analysis can be applied to test selection from both perspectives. Furthermore, we show how animal welfare goals can be included in cost-effectiveness analyses, and we provide a three-dimensional extension to the standard cost-effectiveness analysis if animal welfare loss cannot be valued in monetary terms. To illustrate how cost-effectiveness analysis works in different settings, we apply our model to a simple case of selecting short-term tests for mutagenicity. We demonstrate that including sufficiently high values for animal welfare induces cost-effective replacements of animal testing. Furthermore, we show that the regulator and chemical companies face different tradeoffs when selecting tests. This may lead to different choices of tests or testing systems. 相似文献