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关键词： 联苯胺   线粒体酶   线粒体蛋白质   线粒体DNA   体内染毒   体外染毒   同工酶分析   表达差异  

摘要： 由于线粒体具有其特殊的结构和功能,因而受到了越来越多的关注.目前环境化学物质对线粒体的损伤作用是人们关心的重要课题.本论文用分子生物学方法研究了联苯胺对鱼、猪和鼠肝线粒体的损伤作用,得到以下结果:1.研究了联苯胺对动物肝线粒体酶系统的作用.实验结果表明,动物肝线粒体酶活性呈现出激活.减弱.抑制的变化趋势.在联苯胺作用下鱼和猪肝线粒体酶表达差异的研究中,低浓度联苯胺作用下,GSH-Pox和SOD均表现出一种应急反应,随着联苯胺浓度的进一步增加,武昌鱼肝脏线粒体GSH-Pox和SOD活性均呈现出逐步下降的趋势;低浓度联苯胺对大鼠线粒体的作用,使ATPasc和SOD酶的活力都有一定的升高,表明大鼠肝脏线粒体对外来毒物刺激有一种应激反应.随着联苯胺剂量浓度升高,酶的活性相应地下降.2.研究了联苯胺作用下线粒体蛋白质表达差异.实验结果表明,不同浓度联苯胺作用于猪和鱼肝线粒体时,线粒体蛋白质表达条带数先增加后减少;联苯胺对鱼肝线粒体作用不同时间时,线粒体蛋白质表达条带数先减少后趋基本不变;联苯胺对发育过程中的鱼肝线粒体作用时,线粒体蛋白质的表达条带数呈现先增加后减少的趋势.3.研究了联苯胺对线粒体DNA损伤作用.实验结果表明,鲫鱼线粒体DNA上有两个EcoR Ⅰ的酶切位点;联苯胺先与小分子量的线粒体DNA结合,使线粒体DNA链断裂,随着染毒时间的延长,大分子量线粒体DNA片断开始减少,低分子量线粒体DNA片断增多.

关键词： 稀释方法   微生物学   食品检验   饲料   生物测定   悬浮液   肉制品   饮食   比率的   生物试验   肉   农产品   微生物分析   试样制备   定义   规范(验收)   试验室   稀释   食品  

标准号: EN ISO 6887-2-2003

关键词： circadian clock genes   suprachiasmatic nucleus   complex traits   ENU mutagenesis   sleep-wake cycle  

摘要： During the past decade, the molecular mechanisms underlying the mammalian circadian clock have been defined. A core set of circadian clock genes common to most cells throughout the body code for proteins that feed back to regulate not only their own expression, but also that of clock output genes and pathways throughout the genome. The circadian system represents a complex multioscillatory temporal network in which an ensemble of coupled neurons comprising the principal circadian pacemaker in the suprachiasmatic nucleus of the hypothalamus is entrained to the daily light/dark cycle and subsequently transmits synchronizing signals to local circadian oscillators in peripheral tissues. Only recently has the importance of this system to the regulation of such fundamental biological processes as the cell cycle and metabolism become apparent. A convergence of data from microarray studies, quantitative trait locus analysis, and mutagenesis screens demonstrates the pervasiveness of circadian regulation in biological systems. The importance of maintaining the internal temporal homeostasis conferred by the circadian system is revealed by animal models in which mutations in genes coding for core components of the clock result in disease, including cancer and disturbances to the sleep/wake cycle.

关键词： 单核细胞增生性利斯特氏菌   计数   试验   微生物学   分析方法   抽样方法   验证   试验媒体   定义   农产品   方法   微生物   检测   水平的   分析   细菌纲   微生物分析   食品检验   介质   细菌计数方法   食品   实验室试验   饲料  

标准号: ISO 11290-2 AMD 1-2004

摘要： This is Amendment 2 to ISO 11290-2-1998 (Microbiology of food and animal feeding stuffs — Horizontal method for the detection and enumeration of Listeria monocytogenes —Part 2: Enumeration method)

关键词： chordate evolution   neural plate   neurulation   cell lineage   ion channels  

摘要： With little more than 330 cells, two thirds within the sensory vesicle, the CNS of the tadpole larva of the ascidian Ciona intestinalis provides us with a chordate nervous system in miniature. Neurulation, neurogenesis and its genetic bases, as well as the gene expression territories of this tiny constituency of cells all follow a chordate plan, giving rise in some cases to frank structural homologies with the vertebrate brain. Recent advances are fueled by the release of the genome and EST expression databases and by the development of methods to transfect embryos by electroporation. Immediate prospects to test the function of neural genes are based on the isolation of mutants by classical genetics and insertional mutagenesis, as well as by the disruption of gene function by morpholino antisense oligo-nucleotides. Coupled with high-speed video analysis of larval swimming, optophysiological methods offer the prospect to analyze at single-cell level the function of a CNS built on a vertebrate plan.

关键词： sperm   sex selection   cattle   flow cytometry   economics  

摘要： Sperm from many mammalian species can be sexed by flow cytometry/cell sorting at about 90% accuracy without damaging them unduly. However, because sperm are evaluated one at a time, in series, the number of sexed sperm produced per unit time is limited. Furthermore, the equipment required currently is expensive, in the order of US $300,000 per machine. Despite these limitations, commercialization of this technology has begun with bovine semen, in part by inseminating cattle with relatively low number of sperms. No other approach to sexing sperm in any practical way is likely to be available within the next few years. The constraints for commercial application of sexed sperm in cattle can be somewhat lowered fertility, the high costs of equipment and skilled personnel, and costs of intellectual property such as licensing fees and royalty payments. Most economic analyses indicate that farmers can afford to pay US $10-20 more per dose of sexed sperm than unsexed sperm if costs must be recouped by selling milk or meat. When the product is breeding stock or for certain niche applications, a higher price for sexed semen may be justified. Sexed sperm will be used more broadly in cattle only when improved production and/or efficiency can compensate for the extra costs of purchasing sexed sperm. (C) 2003 Elsevier B.V. All rights reserved.

关键词： Animals   China   Evolution   Forelimb/anatomy & histology   Fossils   Hindlimb/anatomy & histology   Marine Biology   Polydactyly   Reptiles/anatomy & histology  

摘要： The earliest four-limbed vertebrates, or tetrapods, lived between 370 million and 354 million years ago, during the Late Devonian period, and typically had more than five digits (polydactyly). We have discovered that a preaxial form of polydactyly, in which extra digits are positioned anterior to the first digit, has unexpectedly re-emerged in a marine reptile from the Early Triassic period about 242 million years ago -- the overall morphology of both the manus and pes closely resemble those of the earliest tetrapods. Until now, no post-Devonian tetrapod has been found with a comparative type of polydactyly, so the new amniote provides a striking example of convergent evolution.

关键词： REPRODUCTION   NONFICTION  

摘要： Reviews the book 'Reproductive Biology of Invertebrates: Progress in Asexual Reproduction,' vol. 11, edited by R.N. Hughes, K.G. Adiyodi. and R.G. Adiyodi.

关键词： 神经肽Y   NPY   优力安肽   动物采食   激素分泌   生理过程   生理调控剂   动物生物学  

摘要： 神经肽Y(NPY)属活性肽,与动物采食、激素分泌等重要生理过程密切相关,现阶段国内外研究日益深入,已经出现了新一代的内源性以调控NPY为主要目的的新型生理调控剂(如重庆民泰生产的优力安肽)。本文主要对NPY及其代表产品优力安肽的应用作简要分析、展望。