首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
正物种保护是生物多样性保护的核心问题。野生动物资源是地球生物多样性的重要组成部分,不仅在维护整个生态系统的稳定及其生态服务方面具有重要功能,更是生态系统健康发展的标志(Hoffmann et al.,2010;Scheffers et al.,2012;魏辅文等,2014)。然而,由于全球人口爆炸性增长、环境变化和过度利用,当前物种灭绝的速率比历史背景灭绝率高100-  相似文献   

2.
<正>森林具有气候调节、水源涵养、生物多样性保护等诸多生态服务功能(Millennium Ecosystem Assessment,2005;van der Werf et al.,2009),同时减少毁林和森林退化也是减缓温室气体排放协议REDD+的重要内容(DeF ries et al.,2007;Grassi et al.,2008)。为了改善日益恶化的生态状况,提高森林资源的蓄积量,自20世纪70年代以来,中国实施了六大林业重点工程,包括天然林保护工程、"三  相似文献   

3.
<正>生物多样性保护的需求迫在眉睫(Pimm et al.,1995;Balmford et al.,2003;Jenkins,2003)。在可利用资源有限的情况下,人们广泛关注的是如何以最小代价实现生物多样性的最佳保护,而最有效和普遍的做法就是保护生物多样性热点地区(WilsonFrancis,1988;Balmford,1998;Reid,1998;Myers et al.,2000)。保护生物地理学正是在这一背景下应运而生的,作为一门新兴的分支学科,它最早由  相似文献   

4.
随着模式植物拟南芥(Arabidopsis thaliana)和水稻(Oryza sativa)基因组测序工作的完成,国际植物科学的研究在近年来得到了极大的推动.我国植物科学领域也在整体上取得了重大进展,特别是水稻基因组框架图(Yu et al.,2002)和4号染色体基因组精细图(Feng et al.,2002)以及水稻控制分蘖的MOCl基因发现(Li et al.,2003)等重大研究成果在Science和Nature等国际顶级科技刊物上的发表,使国际科学界对中国的科学研究水平刮目相看,亦使中国科学家为之振奋.  相似文献   

5.
湖南壶瓶山国家级自然保护区哺乳动物多样性的时空格局   总被引:1,自引:0,他引:1  
正对生物多样性的定量分析,是生态学、生物地理学和保护生物学的中心议题之一(Purvis and Hector,2000; Brooks et al.,2006; Pavoine and Bonsall,2011)。自然保护地(protected area)不仅是地球生物多样性的"诺亚方舟",更应该是探索人与自然和谐共存方式、维持地球可持续发展的示范地(Higgins et al.,2004)。  相似文献   

6.
灵长类动物类固醇激素的研究已经在很多物种间展开(Cariso et al.,1999;Lutz et al.,2000;He et al.,2001;Yan and Jiang,2006;Brandon et al.,2008;Lu et al.,2010;Kim et al.,2012)。特别是对于没有明显发情特征的灵长类动物,类固醇激素的变化可以为它们的繁殖状态提供更多可靠的评估(Fujita et al.,2001)。自然状态下野生动  相似文献   

7.
正Dear Editor,Since September 2012, the Middle East respiratory syndrome coronavirus (MERS-CoV) cases have been reported in more than 27 countries, and more than 2,000 cases have been confirmed in the laboratory (http://www.who.int/emergencies/mers-cov/en/). MERS-CoV causes an acute and severe respiratory illness with a high mortality rate(~35%) in humans (Shi et al., 2017, Zaki et al., 2012).Neutralizing antibodies targeting the spike of MERS-CoV have been shown to be a therapeutic option for treatment of lethal disease (Agrawal et al., 2016, Ying et al., 2014).  相似文献   

8.
<正>陆生脊椎动物是生物多样性保护和管理评价的重要指示类群(Morrison et al.,2007;Liu et al.,2013)。全球多数生态系统中,许多大中型脊椎动物的种群数量在急剧下降,不少物种甚至遭遇灭顶之灾。而人类活动影响(如猎杀、森林砍伐、外来物种侵入、栖息地破坏和片断化等)是引起这些野生动物种群和群落变化的直接或间接原因(Morrison et al.,2007)。同时,野生动物种群和群落变化对生态系统其他物种也产生了严重的生态后果,如食果动物的  相似文献   

9.
林天瑞 《古生物学报》2019,58(4):436-444
通过对我国己经正式发表的Mufushania三叶虫的18个种模式标本的头盖特征进行Q型聚类分析,并结合传统定性分析后,提出其中Mufushania shalangensis Zhang and Zhou inZhang et al.,1980,M.angustilimbata Zhang and Zhou inZhang et al.,1980,和M.kailiensis(Yuan in Yuan et al.,2002)(=Elrathiella kailiensis Zhou in Lu et al.,1974)等3种应从Mufushania属中删除,对余下15个种,通过修订,转移和归并为2个种:M.nankingensis Lin,1965和M.bella(Yuan in Yuan et al.,2002)。本文将对研究我国寒武纪第二世晚期褶颊虫类三叶虫系统演化、生物地理分区以及华北与华南生物地层划分和对比,提供重要依据。  相似文献   

10.
Recently, the CRISPR/Cas9 system has been used as a powerful tool for genome editing in many species (Jinek et al., 2012;Cong et al., 2013;Wright et al., 2016;Li et al., 2017;Deng et al., 2018). The CR1SPR/Cas9 system can not only be used as a useful technology to disrupt endogenous genes but also expand numerous other applications, such as precise base editing (Komor et al., 2016;Zong et al., 2017), regulation of gene expression (Gilbert et al., 2013), and gene replacement or insertion (Wang et al., 2017).  相似文献   

11.
Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.  相似文献   

12.
13.
In order to determine if the absence of vitamin C in the diet of capybaras (Hydrochoerus hydrochaeris) causes scurvy, a group of seven young individuals were fed food pellets without ascorbic acid, while another group of eight individuals received the same food with 1 g of ascorbic acid per animal per day. Animals in the first group developed signs of scurvy-like gingivitis, breaking of the incisors and death of one animal. Clinical signs appeared between 25 and 104 days from the beginning of the trial in all individuals. Growth rates of individuals deprived of vitamin C was considerably less than those observed in the control group. Deficiency of ascorbic acid had a severe effect on reproduction of another population of captive capybaras. We found that the decrease in ascorbic acid content in the diet affected pregnancy, especially during the first stages. The results obtained suggest that it is necessary to supply a suitable quantity of vitamin C in the diet of this species in captivity.  相似文献   

14.
15.
The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.  相似文献   

16.
17.
18.
19.
Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号