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Genomics research has enabled crucial insights into the adaptive evolution of Mycobacterium tuberculosis as an obligate human pathogen. Here, we highlight major recent advances and evaluate the potential for genomics approaches to inform tuberculosis control efforts in high-burden settings.  相似文献   

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陈思亮 《生态学报》1984,4(1):108-109
近二十年来,生态学研究工作格外生气勃勃,其主要表现为:科研经费不断增加;专业队伍更加壮大;各种有关的杂志和书籍源源不断地问世以及研究机构越来越多。所有这些给这门学科无论在其深度上,或在其广度上都带来深刻的变化。人们已经能够运用生态学理论,对许多尤其在动植物生理生态学,微生物生态学以及在动植物间相互作用等方面的生态学过程,作出了令人信服的解释。在个体及物种研究  相似文献   

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为评估浙江省陆域生态保护红线科学性,本研究从生态安全格局视角出发,基于生态系统全过程的理念评价其生态效应。在明确生态保护红线三重内涵的基础上,构建评价指标体系,应用InVEST模型、净初级生产力定量分析等方法识别生态源地,评估红线斑块重要性;应用最小阻力值模型、重力模型等方法构建生态廊道体系,评估红线连通性;此外,通过景观格局指数、叠置分析等方法评估红线破碎化与协调性。结果表明: 从生态保护重要性看,浙江省生态保护红线保护规模较大,但13.5%的红线区保护重要性不高,省级生态源地中约40%的斑块未被纳入生态保护红线保护区。从空间结构整体性看,生态保护红线连通性不足,核心生态廊道占有率低于15%,部分县市红线斑块较为破碎。从系统间协调性看,生态保护红线跨行政区衔接性较好,但仍需注意平原地区因供需矛盾而导致的划定不实与破碎化现象。借鉴生态安全格局提出红线优化调整的相关策略,可为生态空间管理提供科学参考。  相似文献   

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With key work in the 1950s and 1960s, the 1970 Nobel laureate Julius Axelrod made major contributions to the development of pineal science. Looking back at some of his accomplishments in and for the field, we feel that lessons can be derived for future work regarding impairments of the pineal gland's and melatonin's many functions for promoting health and preventing disease in man.  相似文献   

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Thirty years ago, De Bold et al. (20) reported that atrial extracts contain some biologically active peptides, which promote a rapid and massive diuresis and natriuresis when injected in rats. It is now clear that the heart also exerts an endocrine function and in this way plays a key role in the regulation of cardiovascular and renal systems. The aim of this review is to discuss some recent insights and still-debated findings regarding the cardiac natriuretic hormones (CNHs) produced and secreted by cardiomyocytes (i.e., atrial natriuretic peptide and B-type natriuretic peptide). The functional status of the CNH system depends not only on the production/secretion of CNHs by cardiomyocytes but also on both the peripheral activation of circulating inactive precursor of natriuretic hormones and the transduction of the hormone signal by specific receptors. In this review, we will discuss the data supporting the hypothesis that the production and secretion of CNHs is the result of a complex integration among mechanical, chemical, hemodynamic, humoral, ischemic, and inflammatory inputs. The cross talk among endocrine function, adipose tissue, and sex steroid hormones will be discussed more in detail, considering the clinically relevant relationships linking together cardiovascular risk, sex, and body fat development and distribution. Finally, we will review the pathophysiological role and the clinical relevance of both peripheral maturation of the precursor of B-type natriuretic peptides and hormone signal transduction.  相似文献   

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Despite numerous randomized clinical trials over the last three decades for identifying the optimal treatment option for lupus nephritis, renal involvement still significantly impacts the survival and quality of life of patients with lupus and the search for the ideal immunosuppressive regimen is far from complete. The purpose of this review is to summarize the major recent achievements in the field. More specifically, the following topics will be discussed: intravenous cyclophosphamide versus mycophenolate mofetil (MMF) for induction; azathioprine versus MMF for maintenance; targeted therapies. The review will address clues for optimal global care, such as the need for complete initial evaluation, the importance of patient education, the unmasking of non-compliance to therapy, the reason for an early treatment switch in non-responding patients, the need for prolonged immunosuppression, optimal renal protection, and prevention of cardiovascular disease and other comorbidities.  相似文献   

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The discovery of the natriuretic properties of atrial muscle extracts pointed to the existence of an endocrine function of the heart that is now known to be mediated by the polypeptide hormones atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP). On the basis of such a finding, approximately 27 000 publications to date have described a wide variety of biological properties of the heart hormones as well as their application as therapeutic agents and biomarkers of cardiac disease. Stimulation of secretion of ANF and BNP from the atria is mediated through mechanisms involving G proteins of the G(q) or G(o) types. We showed that the latter type underlies the transduction of muscle stretch into stimulated secretion and that it is more highly abundant in atria than in ventricles. The Gα(o)()-1 subunit appears to play a key role in the biogenesis of atrial granules and in the intracellular targeting of their contents. Protein interaction studies using a yeast two-hybrid approach showed interactions between Gα(o)()-1, proANF, and the intermediate conductance, calcium-activated K(+) channel SK4. Pharmacological inhibition of this channel decreases ANF secretion. Unpublished studies using in vitro knockdowns suggest interdependency in granule protein expression levels. These studies suggest previously unknown mechanisms of intracellular targeting and secretion control of the heart hormones that may find an application in the therapeutic manipulation of circulating ANF and BNP.  相似文献   

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An ecological hypothesis concerning the relative importance of factors governing the success of Oxalis acetosella on mesic upland forest sites in southern Finland was formulated and tested statistically by means of a multivariate linear model. The data consisted of a stratified random sample of 40 plots with biological measurements and associated observations on environmental variables. The covariance matrix between the incorporated variables was computed and the model parameters were estimated using the method of maximum likelihood provided by the computer programme LISREL V. The results supported the hypothesis based on previous observations and experiments: Oxalis acetosella benefits from a high nutrient level of the soil, but is decisively dependent on the shelter provided by the tree stand. When both spruce stands and well-lit pine stands on mesic and relatively rich forest sites were considered simultaneously, only a weak correlation was found between light availability and site fertility. Accordingly, the presumed value of Oxalis acetosella as an indicator of site fertility appears to be questionable. The adequacy of linear modelling in an ecological context is discussed. The kind of models applied in this study have only a limited application range in non-experimental ecological research. However, linear modelling may contribute to solving particular ecological problems in cases where short environmental gradients are considered so that nonlinearity is not a dominant feature.  相似文献   

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Reintroductions are increasingly being used to restore species and ecosystems. However, chances of successful establishment are often low. Key to improving success is careful consideration of threats, threat mitigation, monitoring, and subsequent improvement to management. We demonstrate this planning, implementation, and review process using the reintroduction of an endangered mesopredator, the eastern quoll Dasyurus viverrinus, in the first attempt to reestablish it in the wild on mainland Australia. In March 2018, 20 captive‐bred quolls (10 male, 10 female) were released into Booderee National Park and monitored via telemetry, camera, and cage trapping. There were many unknowns and, despite thorough consideration of threats, there were surprising outcomes. Within 3 months, 80% of animals had died; half due to predation, an expected threat. Other threats were unexpected yet, due to good monitoring and responsive management, were quickly detected and effective mitigation implemented. These learnings have been incorporated into revised translocation procedures. One year later, four founder quolls remained and had successfully bred. We highlight lessons applicable to other reintroductions. These are, the importance of: (1) conducting a thorough review of threats and implementing appropriate mitigation; (2) targeted monitoring and responsive management; (3) effective communication, education, and engagement with the local community and stakeholders; and (4) ensuring learnings are disseminated and incorporated into future translocation plans. Threat assessment is an important step in identifying potential reasons for failure. However, actual threats can be realized only via experimentation and monitoring. Applying this knowledge to future reintroduction attempts can increase their chance of success.  相似文献   

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Most field ecology is conceived and financed by scientists from urban areas but is actually carried out in rural areas. Field staff can either be imported from urban areas or recruited from local residents. We evaluated the advantages and disadvantages of involving rural residents as local technicians over a 25- year period at active field research site in Costa Rica. We defined "local technicians" as local residents with no university education who acquired significant experience in field data collection, data management and/or laboratory work. We analyzed the experiences of incorporating these technicians into field research in developing countries from the points of view of scientist and of the local technicians themselves. Primary data were written responses from to a standardized survey of 19 senior scientists and Ph.D. students,and results from standardized personal interviews with 22 local technicians. Researchers highlighted the advantages of highly-skilled technicians with minimal staff turnover, as well as the technicians' knowledge of local ecological conditions. Local technicians considered the primary advantages of their jobs to be opportunities for continuing education training in science as well as cultural enrichment through interactions with people of different cultures. The main challenges identified by researchers were the lack of long-term funding for projects and extended training required for local technicians. Local technicians can be of great benefit to research projects by providing high-quality data collection at reasonable costs with low staff turnover. Over the last 25 years the research model at the field station we studied has evolved to the point that most long-term projects now depend heavily on local technicians. This model of involving local technicians in long-term research has multiple benefits for the researchers, the technicians and the local community, and could be adapted to a variety of settings in rural areas of developing countries.  相似文献   

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大河岸线作为流域的重要生态空间,其内涵属性、空间格局和生态功能都具有显著的整体性。从岸线的陆域原真性、水陆生态渐变性、生境依存性及生物多样性等维度,分析了大河岸线生态完整性的科学内涵。结合国内外河流岸线生态评价研究,建立了大河岸线生态完整性的科学表征体系,提出各项指标评估和综合分级方法,并对长江岸线生态完整性进行了评估。结果表明,长江岸线生态完整性总体处于中等水平,从上游到下游沿岸各地市岸段生态完整性得分总体逐步降低;中上游地市岸段受到滨江湿地和洲岛发育程度及湿地保护状况等因素制约,下游地市岸段则受土地开发强度、自然岸线保有率、水陆连通性等制约。虽然中下游岸线有较高的开发程度且受长江大堤的约束,生态完整性受到明显影响,但在相同条件下生态完整性仍然有较大差异性,部分地区如铜陵段、安庆段和上海段仍保持了较高的完整性。大河岸线生态完整性的评估有助于形成既尊重自然规律、保护生态环境、保障防洪安全及供水安全,又能支撑社会经济发展、促进高效集约利用的长江生态岸线格局。  相似文献   

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 We simulated male gypsy moth flight phenology for the location of 1371 weather stations east of 100° W longitude and north of 35° N latitude in North America. The output of these simulations, based on average weather conditions from 1961 to 1990, was submitted to two map-interpolation methods: multiple regression and universal kriging. Multiple regression was found to be as accurate as universal kriging and demands less computing power. A map of the date of peak male gypsy moth flight was generated by universal kriging. This map itself constitutes a useful pest-management planning tool; in addition, the map delineates the potential range of the gypsy moth based on its seasonality at the northern edge of its current distribution in eastern North America. The simulation and map-interpolation methods described in this paper thus constitute an interesting approach to the study and monitoring of the ecological impacts of climate change and shifts in land-use patterns at the sub-continental level. Received: 26 May 1998 / Accepted: 6 July 1998  相似文献   

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闵庆文  何永涛  李文华  李贵才 《生态学报》2004,24(10):2130-2135
从农业气象学原理出发 ,森林植被的生态需水可以理解为林地的蒸散耗水量。根据土壤水分有效性的划分 ,林木暂时凋萎含水量和生长阻滞含水量分别是能保证林木基本生存和正常生长时土壤含水量的下限 ,据此可以作为林地最小生态需水定额和适宜生态需水定额计算的依据 ,其数值通过计算林地的潜在蒸散并利用土壤水分修正系数和林木系数进行订正获得。根据遥感图像资料 ,在 GIS支持下 ,计算了泾河流域现有林地生长季的最小生态需水量和适宜生态需水量 ,分别为 2 0 396 0× 10 4 m3和340 330× 10 4 m3。  相似文献   

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Establishing new populations by transferring founder individuals from source populations has been effective for managing the recovery of many threatened species including some weta (Orthoptera: Anostostomatidae) in New Zealand. These large-bodied flightless insects are ‘flagship species’ for insect conservation in New Zealand and many are rare or threatened. The declining abundance of most weta species, particularly giant weta, can be attributed to the introduction of mammalian predators, habitat destruction, and habitat modification by introduced mammalian browsers. New populations of some weta have been established in locations, particularly on islands, where these threats have been eliminated or severely reduced in order to reduce the risk of extinction. Some populations were established to provide food for endemic vertebrates, ecosystem restoration and ready access for the general public. We illustrate how methods for both transferring weta and monitoring them have become more sophisticated by using a series of case studies. Other transfers of weta not included in the case studies are also summarised. We conclude by re-iterating the importance of documenting the transfer and post-release monitoring for all insect transfers, both for biogeographical reasons and to provide information to improve future transfers.  相似文献   

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县域生态保护成效评估方法——以峨山县为例   总被引:2,自引:0,他引:2  
县域是我国基本的行政单元,建立县域生态保护成效评估方法是完善我国生态文明制度建设重要任务。生态系统生产总值(GEP)是指一定区域在一定时期内生态系统为人类福祉提供的最终产品与服务及其价值总和,开展县域GEP核算可以客观反映县域的生态系统状况和生态保护的成效。以省级生态文明县——峨山彝族自治县为例,研究了县域GEP的核算指标体系和核算方法,开展了峨山县GEP核算,分析了峨山县GEP构成及其变化趋势。结果表明:(1)峨山县生态系统产品与服务可以分为产品提供、调节服务和文化服务3大类15项;(2)2015年,峨山县GEP为158.42亿元,气候调节功能和水源涵养功能是最主要的服务功能,二者总和占当年GEP的62.02%;(3)2000年以来,峨山县GEP明显提高,剔除价格因素后,共增加了25.04%,其中产品提供和文化服务功能价值提升明显,分别增加了236.25%和3004.06%。调节服务价值稳中有升,增加了1.30%。本研究表明,现有的生态环境监测数据和经济社会统计数据基本上可以支撑县域GEP的核算,同时县域GEP的变化能够体现出生态系统的保护成效,并为完善政府绩效考核制度提供依据。  相似文献   

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在细菌与古菌中广泛存在的CRISPR-Cas系统,作为目前发现的原核生物唯一的适应性免疫系统,抵御着病毒和质粒的入侵.自20世纪80年代首次被发现至今,CRISPR-Cas系统的基本情况逐渐清晰,包括名称缩写、分类、进化关系等方面.近年来,由于第二类CRISPR-Cas系统作为一种有潜力的基因编辑工具而逐渐成为应用研究...  相似文献   

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