几种海洋弧菌的密度感应系统及其信号干扰     

白方方  张晓华  韩茵  陈吉祥 《海洋科学集刊》2007,(48):153-165

密度感应(quorun sensing，QS)是细菌通过感受种群密度的变化而控制特定基因表达的一种机制(Miller et al.,2001)。密度感应细菌可以产生和释放特定的化学信号分子,称为自诱导分子(autoinducer，AI)，其浓度随着细菌密度的增加而增加。当少量细菌分泌的自诱导分子进入环境后,由于其浓度太低而无法被细菌中的受体蛋白检测到；但是,当细菌达到一定密度后,自诱导分子的浓度超过一定的阈值.受体蛋白与自诱导分子结合,并将此信号传导到细胞内,特异性地调控特定基因的表达。迄今为止的研究表明,许多细菌都可分泌化学信号分子来协调种群的活动，这些化学信号的种类是多种多样的,而且同一种细菌可以利用多种化学信号和复杂的调节环路来进行通讯。细菌种内和种间的通讯对细菌的存活及与自然生境之间的相互作用至关重要(Miller et al.,2001) 迄今为止研究的密度感应系统主要可分为3类:一类以酰基高丝氨酸内脂(acylated homoserine lactoes，AHL)为自诱导分子,如:费氏弧菌(Vibrio fischeri);一类以多肽为自诱导分子,如:革兰氏阳性细菌;一类是以哈维氏弧菌(V. harveyi)为代表的密度感应系统。在系统中有3种类型的信号分子( Miller et al.2001; Defoirdt et al.2004,Henke et al,2004)作者将着重介绍与海洋弧菌的密度感应系统、信号干扰及其应用相关的研究成果,为今后进一步的研究提供依据。  相似文献   

琼东南盆地深水区L18气田上新统地层圈闭气田形成条件及成藏模式   总被引：2，自引：1，他引：1  

张迎朝  徐新德  甘军  杨希冰  朱继田  杨金海  何小胡  郭潇潇 《海洋学报》2019,41(3):121-133

近期在琼东南盆地超深水区发现了L18气田上新统地层圈闭气田，但在聚气背景、烃源岩、储层沉积成因及天然气输导体系等气田形成条件和成藏模式认识存在争议。通过对该气田形成条件的综合分析，认为上新世轴向古洼槽内地层圈闭、陵水凹陷东洼下渐新统崖城组浅海相烃源岩、上新统限制型重力流砂岩储层和渐新统-中新统断裂垂向沟源通道是形成上新统地层圈闭气田的4个基本条件。中中新世以来盆地中央继承性发育轴向古洼槽和限制型重力流沉积，随着后期地层沉积迁移、差异压实作用，上新统莺歌海组砂岩顶面在轴向洼槽内起伏，并被周边泥岩封盖、封堵，形成了地层圈闭；约3.4 Ma BP，陵水凹陷东洼下渐新统崖城组浅海相烃源岩生成了成熟天然气，沿渐新统-中新统断裂向上运移到上新统莺歌海组重力流沉积砂岩中，再侧向运移至地层圈闭中聚集成藏，具有"烃源岩、圈闭、断裂+砂岩输导层"三要素控藏的上新统地层圈闭成藏模式。  相似文献   

The alignment between satellites and central galaxies: theory versus observations     

X. Kang  Frank C. van den Bosch  Xiaohu Yang  Shude Mao  H. J. Mo  Cheng Li  Y. P. Jing 《Monthly notices of the Royal Astronomical Society》2007,378(4):1531-1542

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安徽池州马头矿区斑岩型钼矿含矿裂隙研究     

居维伟  刘小胡  苏阳 《江苏地质》2022,46(1):34-40

通过对安徽池州马头矿区含矿裂隙的综合研究,进一步认识斑岩型钼矿的含矿裂隙规律,解决此类含矿裂隙发育复杂矿区的矿体对应连接问题,有效指导矿区找矿。通过野外统计、室内数据整理及综合分析,在马头矿区选取代表性钻孔6个、平硐1个及地表露头3个,进行含矿岩体及其围岩节理裂隙特征的统计分析,开展钼矿床含矿裂隙规律研究。对矿区岩体与围岩中的节理裂隙、石英脉、钾长石英脉、断裂破碎带特征进行统计分析,发现矿区岩体与围岩中的节理裂隙特征基本一致,主要节理裂隙有5组,主要矿体含矿优势节理裂隙走向NNE,倾向SE,倾角在40°左右。  相似文献   

Petrogenesis of the Early Jurassic Longtang and Menglong Peraluminous Granites in Tengchong Terrane, and their Tectonic Implication     

WANG Guochang  LIU Zheng  TAN Shucheng  HE Xiaohu  WANG Yuchao  QI Changshi  YE Hui 《《地质学报》英文版》2022,96(6):1979-1990

A comprehensive study of zircon U-Pb geochronology, in situ Hf isotopes, whole-rock major and trace element geochemistry, and Nd isotopes was carried out for two Early Jurassic two-mica granites (Longtang and Menglong) in the southern part of the Tengchong terrane, which is in the northern part of the larger Sibumasu terrane. We assess the origin of the granites and explore their possible genetic relationship to the Paleo-Tethyan regime. LA-ICP-MS zircon U-Pb dating shows that they were simultaneously emplaced in the Early Jurassic (ca. 199 Ma). They have SiO2 contents of 69.7–75.1 wt% and are mainly strongly peraluminous with alumina saturation index (ASI) values ranging from 1.06 to 1.46. They show similar Mg# (0.29–0.42) to experimental partial melts of metasedimentary rocks under continental pressure-temperature (P-T) conditions. They are enriched in light rare earth elements (LREEs) relative to heavy rare earth elements (HREEs), with moderately negative Eu anomalies and flat HREEs patterns. They show negative εNd(t) values (?9.0 to –12.4) and εHf(t) values (?8.0 to ?9.1). Elemental and isotopic data suggest that they most likely to formed by muscovite-dehydration melting of a metapelitic source at lower temperatures in the range of 700°C to 750°C. The granites might represent a post-collisional tectonic setting response to Paleo-Tethyan regime.  相似文献   

鲁西北地区馆陶组热水水化学特征及控制因素     

段晓飞  吴晓华  黄星  孙晓晓 《地质论评》2023,69(Z1):473-475

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Participants’ livelihoods compatible with conservation programs: evidence from China’s grain-for-green program in northern Shaanxi Province     

Dang  Xiaohu  Zhang  Miao  Xia  Zidun  Fan  Liangxin  Liu  Guobin  Zhao  Gaochang  Tao  Rui  Wei  Xuexiao 《GeoJournal》2021,86(4):1639-1655

GeoJournal - As the largest conservation program and payments for ecosystem services in China, the grain-for-green program (GGP) has substantially changed land use and cover, and reduced soil...  相似文献   

黔西南架底金矿床载金黄铁矿的矿物学特征及金的赋存规律研究          下载免费PDF全文

田冲  张文高  何虎军  杨兴科  韩珂  王晓虎  吴玉 《中国地质》2021,48(4):1255-1266

黔西南地区是中国卡林型金矿的主要产地之一,架底金矿作为黔西南地区近年来在玄武岩中新发现的卡林型金矿床,其金的赋存状态一直备受关注。前人研究表明,含砷黄铁矿是架底金矿的主要载金矿物,然而对架底金矿载金黄铁矿以及金的赋存规律一直缺乏深入的研究。文章结合野外实际调研以及室内显微岩相观察研究,首先对矿区黄铁矿进行了期次的划分;然后利用电子探针微区成分分析方法对不同期次的黄铁矿进行研究,结果显示:架底金矿的黄铁矿中,S、As具有明显的负相关性,Au、As存在一定的相关关系,成矿前黄铁矿与成矿期、成矿后的黄铁矿核部具高S、Fe,低As、Au等相似的特征,成矿期黄铁矿的环带具高As、Au的特征,与成矿后的环带(高As不含Au)相比较具明显差异,两者属于不同的热液事件。据此判断矿区载金黄铁矿的结晶顺序为:草莓状低砷无环带黄铁矿→含砷环带黄铁矿(含金)以及均质无环带的细粒黄铁矿→高砷环带黄铁矿(不含金)。这一结论对架底金矿找矿勘查工作具有一定的指示意义。  相似文献   

近年来钻探用超硬材料的发展与展望          下载免费PDF全文

方啸虎  崔祥仁  谢德龙 《探矿工程》2021,48(S1):18-24

超硬材料在工业发展中扮演着举足轻重的角色,特别是地质钻探行业中超硬材料的研制与应用更显突出。以前钻探界有句话：“有什么样的磨料就有什么样的钻进设备和钻进工艺”,这充分说明了它们的因果关系。金刚石钻头随着人造金刚石的品种、结构、性能、品质等方面不断提高,很大程度上满足了地质钻探行业的需求,并推动了钻探行业的飞速发展;同样钻探应用中提出的新需求,又不断促进超硬行业继续探索。两者相辅相成,互相促进,共同发展。本文结合大量实例阐述了地质钻探行业中使用的超硬产品的特点、种类、性能等。真切地期待未来超硬材料能够更精更新,更多地在钻探产业实现创新突破。  相似文献   

Satellite kinematics – II. The halo mass–luminosity relation of central galaxies in SDSS     

Surhud More †  Frank C. van den Bosch  Marcello Cacciato  H. J. Mo  Xiaohu Yang  Ran Li 《Monthly notices of the Royal Astronomical Society》2009,392(2):801-816

The kinematics of satellite galaxies reflect the masses of the extended dark matter haloes in which they orbit, and thus shed light on the mass–luminosity relation (MLR) of their corresponding central galaxies. In this paper, we select a large sample of centrals and satellites from the Sloan Digital Sky Survey and measure the kinematics (velocity dispersions) of the satellite galaxies as a function of the r -band luminosity of the central galaxies. Using the analytical framework presented in More, van den Bosch & Cacciato, we use these data to infer both the mean and the scatter of the MLR of central galaxies, carefully taking account of selection effects and biases introduced by the stacking procedure. As expected, brighter centrals on average reside in more massive haloes. In addition, we find that the scatter in halo masses for centrals of a given luminosity,  σ_{log  M}   , also increases with increasing luminosity. As we demonstrate, this is consistent with  σ_{log  L}   , which reflects the scatter in the conditional probability function   P ( L _c| M )  , being independent of halo mass. Our analysis of the satellite kinematics yields  σ_{log  L} = 0.16  ±  0.04  , in excellent agreement with constraints from clustering and group catalogues, and with predictions from a semi-analytical model of galaxy formation. We thus conclude that the amount of stochasticity in galaxy formation, which is characterized by  σ_{log  L}   , is well constrained, independent of halo mass and in a good agreement with current models of galaxy formation.  相似文献