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1.
每年有大量来自工业、农业、养殖业和城市污水处理厂的废水被排入到水环境中,因此,地球上的水环境面临大量来自生活废水、工农业废水、非法排放的废水及其它废水的污染物质(如抗生素、杀虫剂,除草剂、烃等)的严重挑战,特别是近年来随着集约化养殖的发展,废水污染问题日益突出,并且随着分析手段的进步,能够检测到被排入水环境中的化学污染物质也越来越多,这些化学污染物对水环境中的生物产生有害影响.但是,微生物在污染控制上具有许多重要的作用.因此,本文对微生物在水环境污染物降解中的应用进行了评论.结果表明微生物主要是应用在水产养殖水中,而在其它的水体系(如河、湖、海)的应用较少.  相似文献   

2.
Environmental toxicants are ubiquitous,and many are known to cause harmful health effects.However,much of what we know or think we know concerning the targets and long-term effects of exposure to environmental stressors is sadly lacking.Toxicant exposure may have health effects that are currently mischaracterized or at least mechanistically incompletely understood.While much of the recent excitement about stem cells(SCs)focuses on their potential as therapeutic agents,they also offer a valuable resource to give us insight into the mechanisms and risks of toxicant effects.Not only as a response to the increasing ethical pressure to reduce animal testing,SC studies allow us valuable insight into the true effects of human exposure to environmental stressors under controlled conditions.We present a review of the history of publications on the effects of environmental stressors on SCs,followed by a consolidation of the literature over the past five years on a subset of key environmental stressors of importance to human health and their effects on both embryonic and tissue SCs.The review will make constructive suggestions as to areas of toxicant research where further studies are needed,as well as making indications of the potential utility for advancing knowledge and directing research on environmental toxicology.  相似文献   

3.
走进内蒙     
孙丹辉 《化石》2016,(1):61-65
2015年8月1日,我们每一个人收拾好行囊,整装待发,在邓涛老师带领下踏上了去往内蒙古的征程,拉开了探索灰色生命之旅的序幕. 队伍由两辆车、8人组成,我们早晨7点从中国科学院古脊椎动物与古人类研究所出发,披着清晨的阳光,摆脱城市的拥挤,缓缓地“逃离”了北京城.直到抵达张北之后我们的车子才能像矫健的马儿一样驰骋在广袤的公路上,沿途没有了城市的喧闹,没有了交通的堵塞,伴随我们的只有那一眼望去蓝蓝的天空、随风摆动的小草,以及那迷人的风景,偶尔打开车窗,一股凉爽的清风扑面而来,沁人心脾.经过一路的颠簸,我们在傍晚时刻到达锡林浩特,当地文物保护站的同志为我们安顿好了一切.  相似文献   

4.
本文记了分别采自云南高黎贡山的栅蛛科栅蛛属Hahnia 2新种:垭口栅蛛,新种S.yakouensis sp.nov.和肾形栅蛛,新种S.reniformis sp.nov..垭口栅蛛后眼列前曲,交媾腔大,扁圆形,交媾孔1个,位于交媾腔下缘,交媾管粗,呈"人"字形下行分成2支再向两侧扭曲.纳精囊有一肓管斜向上伸出,鉴于上述特征而与Hahnia mridulae Tikader,1970不同.肾形栅蛛交媾孔2个,位于生殖厣腹面中央,纳精囊1对,大,肾形,插入器始于生殖球左下方,鉴于上述特征而与Hahnia xinjiangensis Wang et Liang,1989不同. Abstract: The present paper deals with two new species of the genus Hahnia collected from the Gaoligong Mountains Region of Yunnan Province, China: Hahnia yakouensis sp. nov., Hahnia reniformis sp. nov..  相似文献   

5.
中国医科大学博士后科研流动站始建1995年。目前学校设有基础医学、临床医学和生物学3个博士后科研流动站。但由于每年国家财力有限,资助名额很少,在有限条件下建立、健全博士后制度,加强对博士后人员的培养,调动博士后人员的积极性是一项重要的研究课题。  相似文献   

6.
通过现代生物科技专题及相关高考试题的介绍与分析,以开拓学生视野,增强科技意识,激发学生探索生命奥妙和热爱生物科学的情感,为进一步学习现代生物学奠定基础.同时,借助现代生物科技专题作试题背景,具有能力的开放性和情境的新颖性,也有利于考查和培养学生独立获取新知识、收集和处理信息的能力.所选试题涉及现代生物科技前沿的领域有:基因工程、细胞工程、蛋白质工程、癌症和克隆技术等,均体现出对现代生物技术发展的关注.  相似文献   

7.
The development of multilayer network techniques is a boon for researchers who wish to understand how different interaction layers might influence each other,and how these in turn might influence group dynamics.Here,we investigate how integration between male and female grooming and aggression interaction networks influences male power trajectories in vervet monkeys Chlorocebus pygerythrus.Our previous analyses of this phenomenon used a monolayer approach,and our aim here is to extend these analyses using a dynamic multilayer approach.To do so,we constructed a temporal series of male and female interaction layers.We then used a multivariate multilevel autoregression model to compare cross-lagged associations between a male's centrality in the female grooming layer and changes in male Elo ratings.Our results confirmed our original findings:changes in male centrality within the female grooming network were weakly but positively tied to changes in their Elo ratings.However,the multilayer network approach offered additional insights into this social process,identifying how changes in a male's centrality cascade through the other network layers.This dynamic view indicates that the changes in Elo ratings are likely to be short-lived,but that male centrality within the female network had a much stronger impact throughout the multilayer network as a whole,especially on reducing intermale aggression(i.e.,aggression directed by males toward other males).We suggest that multilayer social network approaches can take advantage of increased amounts of social data that are more commonly collected these days,using a variety of methods.Such data are inherently multilevel and multilayered,and thus offer the ability to quantify more precisely the dynamics of animal social behaviors.  相似文献   

8.
Insect-vectored plant viruses can induce changes in plant phenotypes,thus influencing plant-vector interactions in a way that may promote their dispersal according to their mode of transmission (i.e.,circulative vs.noncirculative).This indirect vector manipulation requires host-virus-vector coevolution and would thus be effective solely in very specific plant-virus-vector species associations.Some studies suggest this manipulation may depend on multiple factors relative to various intrinsic characteristics of vectors such as transmission efficiency.In anintegrative study,we tested the effects of infection of the Brassicaceae Camelina sativa with the noncirculative Cauliflower mosaic virus (CaMV)or the circulative Turnip yellows virus (TuYV)on the host-plant colonization of two aphid species differing in their virus transmission efficiency:the polyphagous Myzus persicae,efficient vector of both viruses,and the Brassicaceae specialist Brevicoryne brassicae,poor vector of TuYV and efficient vector of CaMV.Results confirmed the important role of virus mode of transmission as plant-mediated effects of CaMV on the two aphid species induced negative alterations of feeding behavior (i.e.,decreased phloem sap ingestion)and performance that were both conducive for virus fitness by promoting dispersion after a rapid acquisition.In addition,virus transmission efficiency may also play a role in vector manipulation by viruses as only the responses of the efficient vector to plant-mediated effects of TuYV,that is,enhanced feeding behavior and performances,were favorable to their acquisition and further dispersal.Altogether,this work demonstrated that vector transmission efficiency also has to be considered when studying the mechanisms underlying vector manipulation by viruses.Our results also re- inforce the idea that vector manipulation requires coevolution between plant,virus and vector.  相似文献   

9.
BACKGROUND Digestive tract resections are usually followed by an anastomosis.Anastomotic leakage,normally due to failed healing,is the most feared complication in digestive surgery because it is associated with high morbidity and mortality.Despite technical and technological advances and focused research,its rates have remained almost unchanged the last decades.In the last two decades,stem cells(SCs)have been shown to enhance healing in animal and human studies;hence,SCs have emerged since 2008 as an alternative to improve anastomoses outcomes.AIM To summarise the published knowledge of SC utilisation as a preventative tool for hollow digestive viscera anastomotic or suture leaks.METHODS PubMed,Science Direct,Scopus and Cochrane searches were performed using the key words“anastomosis”,“colorectal/colonic anastomoses”,“anastomotic leak”,“stem cells”,“progenitor cells”,“cellular therapy”and“cell therapy”in order to identify relevant articles published in English and Spanish during the years of 2000 to 2021.Studies employing SCs,performing digestive anastomoses in hollow viscera or digestive perforation sutures and monitoring healing were finally included.Reference lists from the selected articles were reviewed to identify additional pertinent articles.METHODS Given the great variability in the study designs,anastomotic models,interventions(SCs,doses and vehicles)and outcome measures,performing a reliable meta-analysis was considered impossible,so we present the studies,their results and limitations.RESULTS Eighteen preclinical studies and three review papers were identified;no clinical studies have been published and there are no registered clinical trials.Experimental studies,mainly in rat and porcine models and occasionally in very adverse conditions such as ischaemia or colitis,have been demonstrated SCs as safe and have shown some encouraging morphological,functional and even clinical results.Mesenchymal SCs are mostly employed,and delivery routes are mainly local injections and cell sheets followed by biosutures(sutures coated by SCs)or purely topical.As potential weaknesses,animal models need to be improved to make them more comparable and equivalent to clinical practice,and the SC isolation processes need to be standardised.There is notable heterogeneity in the studies,making them difficult to compare.Further investigations are needed to establish the indications,the administration system,potential adjuvants,the final efficacy and to confirm safety and exclude definitively oncological concerns.CONCLUSION The future role of SC therapy to induce healing processes in digestive anastomoses/sutures still needs to be determined and seems to be currently far from clinical use.  相似文献   

10.
BACKGROUND Despite overt insulin resistance,adipocytes of genetically obese Zucker rats accumulate the excess of calorie intake in the form of lipids.AIM To investigate whether factors can replace or reinforce insulin lipogenic action by exploring glucose uptake activation by hydrogen peroxide,since it is produced by monoamine oxidase(MAO)and semicarbazide-sensitive amine oxidase(SSAO)in adipocytes.METHODS 3H-2-deoxyglucose uptake(2-DG)was determined in adipocytes from obese and lean rats in response to insulin or MAO and SSAO substrates such as tyramine and benzylamine.14C-tyramine oxidation and binding of imidazolinic radioligands[3H-Idazoxan,3H-(2-benzofuranyl)-2-imidazoline]were studied in adipocytes,the liver,and muscle.The influence of in vivo administration of tyramine+vanadium on glucose handling was assessed in lean and obese rats.RESULTS 2-DG uptake and lipogenesis stimulation by insulin were dampened in adipocytes from obese rats,when compared to their lean littermates.Tyramine and benzylamine activation of hexose uptake was vanadate-dependent and was also limited,while MAO was increased and SSAO decreased.These changes were adipocyte-specific and accompanied by a greater number of imidazoline I2 binding sites in the obese rat,when compared to the lean.In vitro,tyramine precluded the binding to I2 sites,while in vivo,its administration together with vanadium lowered fasting plasma levels of glucose and triacylglycerols in obese CONCLUSION The adipocytes from obese Zucker rats exhibit increased MAO activity and imidazoline binding site number.However,probably as a consequence of SSAO down-regulation,the glucose transport stimulation by tyramine is decreased as much as that of insulin in these insulin-resistant adipocytes.The adipocyte amine oxidases deserve more studies with respect to their putative contribution to the management of glucose and lipid handling.  相似文献   

11.
蜱类染色体的核型研究进展   总被引:2,自引:0,他引:2  
总结了110种蜱的染色体核型。其中:软蜱科3属26种,包括锐缘蜱属12种,钝缘蜱属12种和残喙蝉属2种;硬蜱科8属84种,包括硬蜱属11种、牛蜱属3种、血蜱属16种、革蜱属12种、盲花蜱属5种、花蜱属19种、扇头蜱属6种和璃眼蜱属12种。 性别决定为XO,XX,XY,XX和X_1X_2Y,X_1X_1X_2X_23个系统。  相似文献   

12.
甘肃鸡类物种多样性研究   总被引:3,自引:0,他引:3  
刘乃发 《动物学研究》1993,14(3):233-239
甘肃鸡类有19种,随纬度变化形成了物种多样性梯度。本文通过气候(年无霜天数、元月均温、年均温、7月均温和年降水量),海拔高差,纬度和植被类型多样性与各县鸡类多样性相关统计分析,揭示了7月均温,年均降水量,海拔高差和纬度是控制甘肃鸡类多样性的主要因素,而甘肃鸡类多样性与植被类型多样性无关。在降水量400—650mm和海拔高差1500—3500m的地带种类最多。一个地区物种的多少不仅取决于其离物种库的远近,还取决于这一地区环境空间异质性程度。  相似文献   

13.
姜科植物的引种   总被引:5,自引:0,他引:5  
华南植物园二十多年来共引种姜科植物23属,135种,3变种,3变型,其中存活18属,103种,2变种,2变型。对长果姜(Siliquamomum tonkinense Baill.)、茴香砂仁「Etlingera yunnanensis(T.L.Wu et Senjen)R.M.Smith」等三级保护植物进行了迁地保护。姜科植物在我园引种有高的成活率,开花结实的种类较多,引种较为成功,特别是原产亚  相似文献   

14.
A comparative study of the leaves of 31 species of Lycopodium was made. The pattern of tracheids varies with the species. Usually they exhibit annular, helical, reticulate, modified or transition forms; none of the species have advanced phylogenetically beyond the scalariform tracheid stage. Mucilage canals have been found in four species. Tracheids are enclosed by a few to several layers of oblique ended, elongated parenchyma cells in most species, but an endodermis is absent. Vascular bundles are encircled by fiber cells in three species. The mesophyll of most species consists of identically shaped cells, although palisade-like tissue has been observed in a few species. The epidermal cells vary from elongated to isodiametric and have either undulated or smooth anticlinal walls, which are deeply pitted in some species. The outer epidermal walls are usually thick and heavily cutinized. Stomates are distributed on both surfaces in 18 species, on the abaxial surface in 11 species, and on the adaxial side in only two species. Most stomates are practically isodiametric in surface view, broader than epidermal cells, usually parallel to the vein, and at the same level as the adjacent epidermal cell. A typical guard cell has a prominent outer ledge and a less developed inner ledge of cutin in most species. Six groupings are suggested, based on similarity of leaf structure and the known chromosome numbers.  相似文献   

15.
澜沧江漫湾电站水库地区爬行动物多样性研究   总被引:2,自引:2,他引:0  
何晓瑞  王忠泽 《四川动物》2000,19(3):123-126
漫湾电站水库地区有爬行动物46种,隶属3目10科37属。特点是:(1)特种多样性很丰富,为中国扑行类种娄11.89%,为云南的30.46%,是云南省和全国爬行类很丰富的地区;(2)东洋界种类占绝对优势(97.83%),没有古北界种类,古北东洋两界广布种仅1种;(3)西南区与华南区种类分别为20及19种;华中区及华中华南两区广布种很少;(5)特有种多,在我国主要产于云南有8种,占17.39%,其中云  相似文献   

16.
茎下垂,长30—50厘米,6—12回二叉分枝,基部直径连叶3毫米,叶软,绿色至灰绿色,指向上方,长3—4毫米,宽1毫米,紧接,覆瓦伏,线状披针形,叶尖内弯,覆盖枝上。孢子叶不明显地变小,孢子囊黄棕色,大过孢子叶。  相似文献   

17.
西双版纳地区不同植被亚型蚁科昆虫群落研究   总被引:30,自引:5,他引:25  
研究了西双版纳地区16各被亚型蚂蚁的特有种、优势种、物种多样性指数、均匀度指数、优势度指数和相似性系数。所采蚂蚁分隶于8亚科66属220种。雨季的季节性十麻蚂蚁物种多样性指数最大,为2.908;旱季的茶园中多样性指数最小,为0.114。以山地雨林和季风常绿阔叶林蚂蚁物各组成相似性系数最大,为0.356;以温暖性叶阔叶林和茶园相似性系数最小,为0.017。16种植被亚型均有特有种,其中半常绿季雨林特  相似文献   

18.
Sexual systems of 139 tree species from a tropical rain forest at Los Tuxtlas, Mexico were investigated to: 1) estimate the relative proportions of hermaphroditic, monoecious, and dioecious species; 2) describe flowers, fruits, and seeds in terms of size and weight; 3) describe flowering and fruiting phenology; and 4) correlate sexuality to pollination and dispersal syndromes, and the successional status occupied in the forest. Hermaphroditism occurred in 63% of the species, monoecism in 9%, and dioecy in 27%. Nondioecious species had larger flowers, but dioecious species had more seeds per fruit. The dioecious condition was associated with small flowers pollinated with unspecialized insects and fleshy fruits dispersed by animals at both species and generic levels. Reproductive traits were more correlated among nondioecious species than dioecious species. Pioneer species had more seeds per fruit, and longer flowering and fruiting periods, but persistent species produced heavier seeds and fruits. Flower and fruit morphological traits, sexual systems, and tree guilds are related in a comprehensive way, and a flow model based on data from this study is presented.  相似文献   

19.
银鲫复合种外源遗传物质整入的RAPD分析   总被引:41,自引:13,他引:28  
在优化RADPD检测条件的基础上,采用40对随机引物,比较分析了银复合物,异育银鲫和兴国红鲤相互间扩增DNA片段的异同性。总的来说,银鲫复合种和异育银鲫具有基本一致的扩增产物,而与兴国红鲤的扩增产物多数不同,相似率分析表明,银鲫复合种与兴国红鲤之间的相似率为31.6%,异育银鲫与兴国红鲤之间的相似率为28.6%。在分析中,除发现银鲫复合种,异育银鲫与兴国红鲤间共有扩增片段外,还发现了银鲫复合种与兴  相似文献   

20.
四株糖单孢菌分离株的分类学研究   总被引:1,自引:0,他引:1  
从广西地区的土样中,分离到4株细胞壁Ⅳ型,糖型A, 无枝菌酸的假诺卡氏菌科的放线菌菌株,编号分别为191、221、202、和212。根据4株 菌的形态学特征和细胞化学特征,将其归入糖单孢菌属。与该属5个已知种的7个代表株进行 的rDNA的BamHI酶切片段长度类型分析(Ribotyping)的结果表明:191为青绿色糖单孢菌(S.viridis),202为青灰色糖单孢菌(S.caesia),221和212为相同的与青绿色糖单孢菌(S .viridis)的亲缘关系最近的种,但不同于已知的任何一个种。  相似文献   

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