极地抗植物病原真菌活性菌株PKS和NRPS基因的克隆与分析   总被引：1，自引：0，他引：1       下载免费PDF全文

彭玉娇  李敬龙  林学政 《海洋科学进展》2014,32(3)

植物常见病原真菌尖孢镰刀菌(Fusarium oxysporum)为指示菌,采用平板扩散法对实验室保藏的38株极地细菌进行了抑菌活性验证,并对其中活性较强的菌株进行了分子鉴定与系统发育分析及次级代谢产物合成功能基因(PKS和NRPS)的克隆与分析。结果表明,38株极地细菌中,13株具有明显的抗病原真菌活性;分子鉴定与系统发育分析表明,11株活性菌株属于Pseudomonas,1株属于Psychrobacter,1株属于Arthrobacter;对活性菌株PKS和NRPS基因的克隆与分析表明,从10株活性菌株克隆到12条NRPS A结构域基因片段,其中5株活性菌株同时含有PKS I型KS结构域基因片段。据此为从聚酮和非核糖体肽等生物合成途径深入研究活性菌株的次级代谢产物提供了基因学证据。  相似文献   

Information for authors     

《极地研究(英文版)》2014,(4)

正1 Aims and Scope Advances in Polar Science(APS)is an international,peer-reviewed journal jointly sponsored by the Polar Research Institute of China and the Chinese Arctic and Antarctic Administration.APS is a comprehensive academic journal dedicated to presentation of multi-disciplinary achievements in Arctic and Antarctic expeditions and research.Its primary purpose  相似文献   

What happened to climate change? CITES and the reconfiguration of polar bear conservation discourse     

《Global Environmental Change》2014

In the past decade, polar bears have become the poster species of climate change. But in March 2013, a joint proposal by the governments of the United States and the Russian Federation to up-list polar bears to Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) diverted public attention from climate change towards the hunting of polar bears. Prior to a vote on the proposal, non-governmental organisations spear-headed a media campaign to support the up-listing. In the United Kingdom the campaign received support from celebrities and was widely reported in English language news media. Narratives of commercial legal and illegal polar bear hunting and the imminent extinction of polar bears were aggressively promoted, rhetorically supported by the manipulation of trade and scientific data. By rendering discourses of commercial hunting and a lucrative global trade in polar bear parts highly visible, sustainable hunting and climate change-induced habitat loss were rendered invisible. Media reports of commercial hunting de-coupled polar bear conservation from climate change mitigation, and disassociated polar bear hunting from regulated indigenous subsistence practices. A review of current polar bear conservation measures and an analysis of media coverage leading up to the CITES decision reveal these conflicting discourses, and suggest that more nuanced media coverage of polar bear conservation is necessary if appropriate multilateral conservation policies are to be enacted and publicly supported.  相似文献   

极摩尔圆法计算二维平均运动学涡度   总被引：2，自引：0，他引：2       下载免费PDF全文

刘江  张进江  张波 《地质科学》2012,47(1):13-21

通过有限应变椭圆长短轴比(R_s)和长轴与剪切面夹角(α)构建极摩尔圆,本文计算得出二维平面应变平均运动学涡度(W_m)计算公式为W_m=cos ,并以此绘制了W_m关于R_s和α的等值线投影图。公式计算和有限应变数值投影都是计算平均运动学涡度的简捷有效的方法。极摩尔圆计算提供了判定剪切类型(简单剪切,纯剪切,减薄一般剪切,增厚一般剪切)的两种方法:α值判定瞬时应变剪切类型; R_s×tan²α值判定有限应变剪切类型。  相似文献   

Review on Research on Paleo-Sea Level Reconstruction Based on Foraminiferal Oxygen Isotope in Deep Sea Sediments     

Li Yue  Wang Rujian  Li Wenbao 《地球科学进展》2016,31(3):310-319

Sea level reconstruction is an important proxy for climate change. It can be compared with other reconstructed climatic factors as well as the results of the computer model-based reconstruction to offer a better recognition of the relationship between sea-level changes and other factors in the climate system. Oxygen isotope record obtained from calcium foraminiferal shell in deep-sea sediments contains global continental ice volume signal which can be used to reconstruct the evolution of paleo-sea level. Researchers reconstructed many long time scale and continuous records of sea level change by using foraminiferal oxygen isotope ratio data. In the future of paleo-sea level reconstruction, however, researchers need to contrast the sea level reconstruction with other climate proxy results to validate its accuracy and employ the interdisciplinary study method to acquire further development.  相似文献   

The impact of thermal maturity level on the composition of crude oils,assessed using ultra-high resolution mass spectrometry     

《Organic Geochemistry》2014

We have examined, using a 12 Tesla FTICR-MS instrument, the impact of varying thermal maturity level on a suite of 9 related crude oils charged from source rocks covering most of the liquid petroleum generating portion of the oil window (0.68–1.11% vitrinite reflectance equivalent (%Re)). The sample suite was analyzed as whole oils under three different conditions, electrospray ionization (ESI) in positive and negative ion mode to analyze basic and acidic components, respectively, and atmospheric pressure photoionization (APPI) in positive ion mode, for sulfur and hydrocarbon species.Increasing oil maturity level had a strong influence on the composition of all compound classes in the oils with several major observations evident:The relative apparent abundances of all heteroatom containing compound classes detected in this study, using all ionization modes, decrease systematically with increasing oil maturation levels. Both aromatic hydrocarbons, detectable in APPI mode, and NSO compound classes (detectable in both ESI and APPI modes), as broad classes, are becoming more aromatic (shift to a greater predominance of higher DBE group members) and dealkylated (decreasing average molecular mass of individual compound groups), with increasing maturation level in the oil suite. Several putative oil maturity level dependent, molecular ratios were identified in the study. Of particular note, the relative abundance ratios of heteroatom compound classes tentatively identified as alkylated carbazoles, quinolines and benzothiophenes, compared to their benzannulated homologues are very sensitive to maturation level. Several groups of compounds show interesting and specific carbon number distributions, suggesting there may be hints of specific molecular markers in the FTICR-MS data. One observation of note is the strong increase in the relative abundance of protonated hydrocarbon components with DBE 5. We speculate this might reflect the presence of previously unreported higher molecular weight diamondoid (diamantane) species in oils with up to 40 carbon atoms or more, at advanced maturity levels. Such species may prove very valuable as molecular markers in highly mature fluids, such as those currently being produced from some shale reservoirs. Covariation of quantitative GC–MS data for alkylated hetero aromatic sulfur and nitrogen compounds in this oil suite, together with the corresponding FTICR-MS data from compounds believed to be, based on accurate mass, alkylated sulfur and alkylated nitrogen compounds, suggests that FTICR-MS already has some very rudimentary quantitation capabilities.  相似文献   

Observations of dawn–dusk aligned polar cap aurora during the substorms of January 21, 2005     

A.M. Du  W. Sun  B.T. Tsurutani  R.N. Boroyev  A.V. Moiseyev 《Planetary and Space Science》2011,59(13):1551-1558

A new type of polar cap aurora, dawn–dusk aligned polar cap aurora (DDAPCA), was detected during the exceptionally intense January 21, 2005 substorm (AE_max=3504 nT). The DDAPCA was located at very high latitude (>85° MLAT) in the polar cap region. As the interplanetary magnetic field (IMF) GSM By component rotated from a positive to a negative value, the DDAPCA tilt angle relative to the dawn–dusk direction rotated anticlockwise and reached ∼45°. It is speculated that the DDAPCA arises from the formation of an X-line in the distant (>80R_E) tail due to polar cap magnetic field reconnection under unusually high solar wind compression conditions.  相似文献   

Large asymmetric polar scarps on Planum Australe, Mars: Characterization and evolution   总被引：1，自引：0，他引：1  

Cyril Grima  François Costard 《Icarus》2011,212(1):96-109

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极移十年尺度波动的多分辨率重建及其统计特性   总被引：1，自引：0，他引：1       下载免费PDF全文

柯熙政  杨廷高  宋琨  吴振森 《地球物理学报》1999,42(6):739-747

极移的频谱分布包含ｆ０、ｆ（－１）和ｆ（－２）分量,研究各个分量的统计特征及其产生机制在天文地球动力学的研究中有着十分重要的地位．本文利用小波分析的正交分解的特点,将地球极移按幂律谱进行分解,提出了核函数的概念,并对校函数的特性进行了分析．结果表明：ｆ（－１）过程的核函数的平均变化周期４３８天,最大变化周期５２５天,最小３４５天,ｆ（－２）过程的核函数的平均变化周期４２６天,最大变化周期４９５天,最小３６０天．ｆ０过程与太阳黑子的变化有很强的相关性,ｆ（－１）和ｆ（－２）分量与太阳活动无关．  相似文献   

Polar climate system modeling in China: Recent progress and future challenges     

Zhaomin WANG  Dake CHEN 《中国科学:地球科学(英文版)》2019,(7):1076-1091

The first fully coupled atmosphere-ocean-sea ice model developed in China was released in the mid-1990s. Since then, significant advances in climate system model developments have been achieved by improving the representations of major physical processes, increasing resolutions, and including an ice-shelf component. There have also been many modeling studies in China on the polar climate system, including weather and sea-ice numerical forecasts to meet the national needs of polar scientific expeditions, assessments of the state-of-the-art coupled model performance, and process-oriented studies. Future model developments and modeling activities will need to address several big scientific questions originating from the polar climate system: i) How will polar ice mass balance evolve and affect global sea level? ii) How can we properly simulate openocean deep convection and quantify its role in driving the lower branch of the global overturning circulation? iii) How are Arctic and Antarctic connected and what caused the contrasting sea ice trends in the two polar regions over the last decades? To address these questions, polar climate system modelers will need to analyze extended observational datasets on a global scale and work together with other polar researchers to develop a more comprehensive and sustainable observation system in the polar regions.  相似文献