转基因动物在生物制药工业中的应用

简要论述了转基因动物的概念、制作方法及应用领域,回顾了转基因动物技术的发展及现状,分析了转基因动物与克隆动物的区别.就转基因动物在制药工业和生物医药领域中的国内外研究与开发应用情况进行了阐述,同时展望了转基因动物制药的发展前景及对社会的影响.     

Yeast, beef and pork extracts counteract Clostridium difficile toxin A enterotoxicity

Clostridium difficile is responsible for a large proportion of nosocomial cases of antibiotic-associated diarrhoea and pseudomembranous colitis. The present study provides evidence that yeast, beef and pork extracts, ingredients commonly used to grow bacteria, can counteract C. difficile toxin A enterotoxicity in vitro and in vivo . In model intestinal epithelial cells the individual extracts could prevent the toxin A-induced decrease in epithelial barrier function and partially prevented actin disaggregation and cell rounding. Mice with ad libitum access to individual extracts for 1 week had almost complete reduction in toxin A-induced fluid secretion in intestinal loops. Concomitantly, the toxin A-induced expression of the essential proinflammatory mediator Cox-2 was normalized. Moreover this protective effect was also seen when mice received only two doses of extract by intragastric gavage within 1 week. These results show that yeast, beef and pork extracts have the potential to counteract the intestinal pathogenesis triggered by C. difficile toxin A.     

Recipient Environment More Important than Community Composition in Determining the Success of an Experimental Sponge Transplant

Human activities have inflicted profound damage upon many ecosystems, and ecologists are now seeking effective means of restoring ecosystems to their natural state. Industrial ports and harbors are highly modified and often depauperate in native fauna. They are typically characterized by poor water quality and modified community composition, both of which may hinder attempts to reintroduce native species. Here, we conducted a field experiment to separate the effects of the recipient environment and community composition on the success of endemic sponge explants in Port Kembla Harbor, NSW, Australia. A reciprocal transplant was conducted between communities originating from six sites that varied in water quality and community composition, enabling us to assess the relative factors simultaneously. A colony of the endemic sponge Tedania anhelans was then inserted into the center of each community, and we quantified the survival, growth, and metal bioaccumulation of sponges over three months. Endemic sponges consistently performed better against resident assemblages when water quality was good. Sponges transplanted to cleaner sites had over double the survivorship and approximately three times the surface area of sponges transplanted to disturbed sites. These patterns were independent of community composition. Bioaccumulation of metals in sponges was correlated with survival; however, other factors such as turbidity may be required to explain sponge mortality at some sites. This study adds to evidence that remediation of the physical and chemical environments may be a prerequisite for biological remediation and demonstrates the value of experimental transplants in assessing restoration potential.     

Inter- and intra-genetic variation of four wild populations of Prosopis using rapd-pcr fingerprints

The species of Prosopis (Leguminosae) are welladapted to grow in the arid regions of the world. In Mexico, nearly 70%of its territory accounts for arid lands and nine species of this genus arefound in the country which are currently utilized for multiple purposes. Giventhat a sustainable exploitation of this important natural resource is necessary,knowledge of the genetic variability of natural populations is required. Thegenetic variation among and within four wild populations of Prosopisglandulosa, P. juliflora, and two ofP. laevigata, located in the Mexican States of Chihuahua(1), Sinaloa (2), Guanajuato (3) and Hidalgo (4), respectively, was determinedusing random amplified polymorphic DNA (RAPDs). There was a genetic variation of72.48% among these four populations, and within them the estimated geneticvariation was 27.52%. Between the populations of P.laevigata the genetic variation obtained was 7.15%, and within them92.85% (AMOVA, P < 0.001). Based on the assumption ofWright's island model, the genetic variation found among populations correspondsto a gene flow (N_em) of 0.09, while the gene flow detected betweenthe populations of P. laevigata was 3.2. A total of 27 RAPDphenotypes were identified in the four populations; among them, 11 correspondedto P. laevigata. The phylogenetic analyses showed that thethree species are differentiated in three clades and that probably P.juliflora was the origin of the other two species. The protogynoustrait of their flowers and the outcrossing are the main factors that may explainthe genetic variation observed in these populations.     

长江下游水生动物群落生物多样性变动趋势初探

对1990－1999年间长江下游江段生物多样性的变动趋势进行了研究,并就群落稳定性与多样性的关系进行了探讨,结果表明,物种多样性指数量大值为1．1112,最小值为0．0327,反映物种均匀度,丰盛度的指数都有不同程度的下降,而反映优势度的指数却有一定程度的上升,优势度指数最大值为1,最小值为0．34046,优势种前6位分别为杂虾,青虾,餐条,吻Qu,蛇Qu,黄颡,表明长江下游江段的生物多样性正在逐步丧失,经济鱼类数量趋减,小型野杂鱼类数量趋增。     

亚高山针叶林土壤动物和土壤微生物对针叶分解的作用（英文）

 通过80片亚高山针叶林土壤有机物层切片的显微观察和统计,并结合微生物（CFU）的培养观察,对亚高山针叶林土壤有机物分解过程中土壤动物和土壤微生物的作用进行了研究。根据可见针叶数目和C/N比率在土壤有机物层的垂直分布变化将分解过程分为3个阶段。真菌数量（CFU）在第一阶段（表层0～2 cm）明显高于第二和第三阶段（深层）;与此相反细菌的数量（CFU）却表层少深层多。具有虫便的针叶在表层（0～2 cm）为最多,而深于2 cm后便急剧减少,至4.5 cm处为零。综合以上结果并结合微形态观察我们认为针叶的分解过程     

体细胞介导制备转基因动物的新途径

体细胞介导制备转基因动物的技术路线是在核移植技术的基础上建立起来的。它的问世不过只有四五年时间 ,但显示了其具有广泛的应用前景。本综述比较了不同制备转基因动物技术的优缺点 ,介绍了体细胞介导制备转基因动物的基本技术路线 ,着重阐述了体细胞转染和整合细胞的克隆 ,以及体细胞介导的转基因技术的局限性和应用前景     

云南野生兜兰的引种栽培

1997～ 2 0 0 1年引种云南野生兜兰 1 3种 ,存苗 2万余株 ,在昆明园林植物园 (金殿 )兰圃栽培。具有引种成活率高、容易栽培、观赏价值高的优点 ,在养护管理实践中确立了一套栽培管理技术措施     

Ames试验在水质检测方面的应用

近年来 ,水体污染日趋严重 ,各国学者从氯化后饮水中分离出多种致突变、致癌物质。为此我们采用Ames试验 ,对珠江流域主要取水点的水源水和对应自来水中的有机致突变物污染情况进行了研究。研究表明 ,部分取水点的有机致突变物污染较严重 ,并且氯化消毒后自来水的致突性大于水源水的致突性。因而 ,加强饮水中致突变物质的检测 ,改进净水消毒剂和净水流程很有必要。     

单细胞动物和多细胞动物的激素印迹

激素印迹是单细胞动物和多细胞动物的一种生理现象,也是选择参与信号识别过程分子的工具。激素印迹后,受体记忆将遗传给子孙后代,因此其对进化的作用可能是很大的。同时,激素印迹还有利于物种的维持。另外,激素印迹过程还是具有终身效应的临时开放系统的一部分。没有印迹,就没有完全的受体成熟,而不成熟的受体是不能和适量的激素结合的。在围 期诸如治疗药物和环境污染剂等人工合成的物质分子易致错误或病理印迹。许多研究表明错误印迹对生物体具有重要的影响。当然,单细胞动物的激素印迹过程与多细胞动物并不完全一样。