罗非鱼源无乳链球菌(Streptococcus agalactiae)新型AI-2信号分子受体RbsB蛋白结晶生长研究   总被引：1，自引：0，他引：1  

樊博琳  潘丽霞  王忠良  黎源  简纪常  王蓓 《海洋与湖沼》2020,51(1):132-140

为了开展无乳链球菌(Streptococcus agalactiae)核糖结合蛋白(Ribose binding protein B,RbsB)结构功能的研究,本实验根据已知无乳链球菌ZQ0910全基因组序列设计相关引物。采用PCR方法扩增其RbsB基因,随后将该基因定向克隆到原核表达载体pGEX-6p-1中,在大肠杆菌BL21(DE3)感受态细胞中进行IPTG诱导表达;采用HRV 3C蛋白酶切除GST标签,分子筛分离获得RbsB蛋白;运用生物信息学软件对RbsB基因序列进行分析,并对RbsB蛋白二级和三级结构进行预测;采用NeXtal Tubes JCSG Core Suite结晶试剂盒筛选蛋白结晶条件。研究结果表明,该基因全长为969碱基,编码322个氨基酸,RbsB蛋白理论分子量33.9ku,等电点为9.41,二级结构中α螺旋结构所占比重最高,建立RbsB蛋白三维结构模式图;经IPTG诱导后表达的融合蛋白分子量为59ku,筛选RbsB蛋白的初始结晶条件为(0.2mol/L di-Potassium hydrogen phosphate,20%(W/V)PEG3350;1.5mol/L ammonium sulfate,25%(V/V)Glycerol),获得RbsB蛋白结晶体。本研究结果可为无乳链球菌核糖结合蛋白(RbsB)的功能解析提供实验及理论基础。  相似文献   

西藏雄村斑岩型铜(金)矿床Ⅰ、Ⅱ号矿体热液黑云母特征及地质意义     

肖鸿天  谢富伟  郎兴海  冉凤琴 《岩石矿物学杂志》2020,39(4):469-480

雄村铜(金)矿区位于西藏冈底斯成矿带中段南缘,由Ⅰ、Ⅱ、Ⅲ号矿体和多个矿化体组成。本文以Ⅰ、Ⅱ号矿体钾硅酸盐化蚀变带内的热液黑云母为研究对象,采用光薄片镜下鉴定、电子探针等分析方法,系统研究了热液黑云母的产状和成分特征。结果显示,雄村矿区Ⅰ号矿体黑云母类型主要为金云母和镁质黑云母;Ⅱ号矿体黑云母类型为镁质黑云母。两个矿体黑云母都具有低Ti(TiO_2 3%)、高Al(Al_2O_315%)的特点,且具有较高的MgO含量,Mg/Fe0.5,K/Na10,显示了与矿化良好的相关性。Ⅰ号矿体热液黑云母平均结晶温度470℃,氧逸度位于镍-氧化镍缓冲剂与磁铁矿-钛铁矿缓冲剂之间(NNO—HM);Ⅱ号矿体热液黑云母平均结晶温度234℃,氧逸度位于镍-氧化镍缓冲剂与铁橄榄石-石英-磁铁矿缓冲剂之间(NNO—FQM),说明Ⅰ号矿体形成于较高温、高氧逸度的热液系统,Ⅱ号矿体形成于相对较低温、低氧逸度的热液系统。此外,Ⅰ号矿体热液黑云母Ⅳ(F)值介于0.61～2.72之间,平均值1.26,Ⅳ(Cl)值介于-5.49～-4.53之间,平均值-5.03,Ⅳ(F/Cl)值介于5.63～7.89之间,平均值6.29;Ⅱ号矿体热液黑云母Ⅳ(F)值介于1.83～3.32之间,平均值2.66,Ⅳ(Cl)值介于-5.64～-4.89之间,平均值-5.31,Ⅳ(F/Cl)值介于7.14～8.68之间,平均值7.97,说明Ⅰ、Ⅱ号矿体都形成于富Cl的热液系统,且Ⅱ号矿体热液较Ⅰ号矿体更富Cl,贫F。富Cl流体易萃取流体中的Cu和Au等金属元素并以Cl的络合物形式运移,在沿构造裂隙向上运移的过程中,物理化学条件发生改变,使得流体中金属元素络合物溶解度降低,促使硫化物沉淀成矿。  相似文献   

喜马拉雅淡色花岗岩——关键金属Sn-Cs-Tl的富集机制     

高利娥  曾令森  严立龙  高家昊  赵令浩 《岩石学报》2021,37(10):2923-2943

关键金属是全球高科技产业不可或缺的战略性资源,其富集机制和成矿作用是目前国际矿床学研究的热点之一。我们对喜马拉雅带吉隆和亚东地区淡色花岗岩开展系统的地球化学研究,发现侵入到藏南拆离系的淡色花岗岩含有较高的Sn、Cs、Tl、Be、W、B、Li和Bi。全岩元素地球化学分析表明,这些淡色花岗岩具有如下特征：（1）富集关键金属元素;（2）为原始岩浆经历斜长石、锆石、独居石、磷灰石、云母分离结晶作用后的残余熔体;（3）关键元素的富集和矿化与花岗岩高度分离结晶作用密切相关。随着分异程度的增强,岩浆变为富挥发分的高SiO₂体系,关键金属元素在残余熔体中富集,并且最后可能形成具有工业价值的矿床。由于地球化学特征的相似性,Cs和Tl呈类质同象替代钾、铷进入云母中。富集关键金属元素的花岗岩在时间上和空间上属于与藏南拆离系相关的同构造侵位花岗岩,藏南拆离系的活动促使了原始岩浆的广泛分离结晶作用,以及后期的关键金属元素（如Rb、Cs和Tl）的富集。  相似文献   

Constraints of Mantle and Crustal Sources Interaction during Orogenesis of Pre- and Post-collision Granitoids from the Northern Arabian-Nubian Shield: A Case Study from Wadi El-Akhder Granitoids,Southern Sinai,Egypt     

Moustafa M. MOGAHED  Khaled M. ABDELFADIL 《《地质学报》英文版》2021,95(5):1527-1550

The Egyptian older and younger granitic rocks emplaced during pre- and post-collision stages of Neoproterozoic Pan-African orogeny, respectively, are widely distributed in the southern Sinai Peninsula, constituting 70% of the basement outcrops. The Wadi El-Akhder, southwestern Sinai, is a mountainous terrain exposing two granitoid suites, namely the Wadi El-Akhder Older Granites (AOG) and the Homra Younger Granites (HYG). The AOG (granodiorites with subordinate tonalite compositions) have geochemical characteristics of medium-K calc-alkaline, metaluminous to mildly peraluminous granitoids formed in an island-arc environment, which are conformable with well-known Egyptian older granitoids rocks, whereas the HYG display calc-alkaline to slightly alkaline nature, peraluminous syeno-, monzogranites and alkali feldspar granites matching well those of the Egyptian younger granites. With respect to the AOG granitoids, the HYG granites contain lower Al2O3, FeO*, MgO, MnO, CaO, TiO2, Sr, Ba, and V, but higher Na2O, K2O, Nb, Zr, Th, and Rb. The AOG are generally characterized by enrichment in LILE and LREE and depletion in HFSE relative to N-MORB values (e.g., negative Nb and Ta anomalies). The geochemical features of the AOG follow assimilation-fractional crystallization (AFC) trends indicative of extensive crustal contamination of magma derived from a mantle source. The chemical characteristics of the AOG are remarkably similar to those of subduction-related granitoids from the Arabian-Nubian Shield (ANS). The compositional variations from monzogranites through syenogranites to alkali feldspar granite within HYG could not be explained by fractional crystallization solely. Correlating the whole-rock composition of the HYG to melts generated by experimental dehydration melting of meta-sedimentary and magmatic rocks reveals that they appear to be derived by extended melting of psammitic and pelitic metasediments, which is similar to the most of younger granitic suites in the ANS.  相似文献   

Comparative Study of Magmatism in East Pacific Rise Versus Nearby Seamounts: Constraints on Magma Supply and Thermal Structure Beneath Mid‐ocean Ridge   总被引：1，自引：0，他引：1  

ZHANG Guoliang 《《地质学报》英文版》2011,85(6):1286-1298

Major elements of 2202 basalts from the East Pacific Rise (EPR) and 888 basalts from near-EPR seamounts are used to investigate their differences in magma crystallization pressures and mantle melting conditions. Crystallization pressure calculation from basalts with 5.0wt%相似文献   

雄县地热田示踪试验的解释及分析     

庞菊梅  王树芳  孙彩霞  高小荣  刘久荣 《城市地质》2011,6(2):12-17

雄县地热田在2009--2010年地热回灌期间开展了示踪试验。示踪试验过程中没有从生产井和观测井群所取水样中检测到示踪剂,但是基于生产井和回灌井之间流动通道的若干假设,对示踪剂回收的浓度及峰值的出现时间进行了模拟预测,对通道的流体流速进行了估计。并且运用水平裂隙介质模型对由于长期地热采暖尾水回灌可能引起的热储冷却进行了预测,为回灌井和生产井的合理井间距的选择,提供一定的依据。  相似文献   

Sequential melting and fractional crystallization: Granites from Guarda-Sabugal area, central Portugal     

Ana Margarida Ribeiro Neiva  Paulo Bravo Silva  Fernando Corfu  João Manuel Farinha Ramos 《Chemie der Erde / Geochemistry》2011,71(3):227-245

Seven distinct phases of Variscan two-mica granite are recognized in the Guarda-Sabugal area. They intruded the Cambrian schist-metagraywacke complex, crystallized in the middle crust, and are syn- to late-D3 (309.2 ± 1.8 Ma), late-D3 (304–300 Ma) and late- to post-D3 (299 ± 3 Ma; ID-TIMS ages on zircon and monazite). Two of the granites, G2 and G5, are close in age and have similar Sr, Nd and O isotope characteristics but contrasting whole rock and mineral features and formed by sequential increasing degree of partial melting of a common metasedimentary protolith. During sequential melting Ti, total Fe, Mg, Ca, Zr, Zn, Sr, Ba and REE contents and (La/Yb)_N increase and Si and Rb contents decrease, plagioclase becomes richer in anorthite and biotite and muscovite richer in Ti and Mg. Each of these granites evolved subsequently by fractional crystallization of quartz, K-feldspar, plagioclase, biotite and ilmenite, defining separate series G2–G3–G7 and G5–G6 containing late Sn-bearing differentiates. Two other granites G1 and G4 represent distinct pulses of magma with individual fractionation trends for major and trace elements and distinct (⁸⁷Sr/⁸⁶Sr)₃₀₀, ?Nd₃₀₀ and δ¹⁸O values.  相似文献   

Petrogenetic modeling of rock variety in the Khalkhab–Neshveh pluton,NW of Saveh,Iran     

MEHDI REZAEI‐KAHKHAEI  DARIUSH ESMAEILY  FERNANDO CORFU 《Island Arc》2011,20(3):329-345

The Khalkhab–Neshveh (KN) pluton is a part of Urumieh–Dokhtar Magmatic Arc and was intruded into a covering of basalt and andesite of Eocene to early Miocene age. It is a medium to high‐K, metaluminous and I‐type pluton ranging in composition from quartz monzogabbro, through quartz monzodiorite, granodiorite, and granite. The KN rocks show subtle differentiation trends strongly controlled by clinopyroxene, plagioclase, hornblende, apatite, and titanite, where most major elements (except K₂O) are negatively correlated with SiO₂; and Al₂O₃, Na₂O, Sr, Eu, and Y define curvilinear trends. Considering three processes of magmatic differentiation including mixing and/or mingling between basaltic and dacitic magmas, gravitational fractional crystallization and in situ crystallization revealed that the latter is the most likely process for the evolution of KN magma. This is supported by the occurrence of all rock types at the same level, the lack of mafic enclaves in the granitoid rocks, the curvilinear trends of Na₂O, Sr, and Eu, and the constant ratios of (⁸⁷Sr/⁸⁶Sr)_i from quartz monzodiorite to granite (0.70475 and 0.70471, respectively). In situ crystallization took place via accumulation of plagioclase and clinopyroxene phenocrysts and concentration of these phases in the quartz monzogabbro and quartz monzodiorite at the margins of the intrusion at T ≥ 1050°C, and by filter pressing and fractionation of hornblende, plagioclase, and later biotite in the granitoids at T = ～880°C.  相似文献   

喜马拉雅淡色花岗岩   总被引：62，自引：33，他引：29  

吴福元  刘志超  刘小驰  纪伟强 《岩石学报》2015,31(1):1-36

在青藏高原南部的喜马拉雅地区,分布有两条世界瞩目的淡色花岗岩带。南带主要沿高喜马拉雅和特提斯喜马拉雅之间的藏南拆离系(STDS)分布,俗称高喜马拉雅淡色花岗岩带,构成喜马拉雅山的主体。北带淡色花岗岩位于特提斯喜马拉雅单元内,又被称之为特提斯喜马拉雅淡色花岗岩带。这些花岗岩多以规模不等的岩席形式侵入到周边沉积-变质岩系之中,或者呈岩株状产出于变质穹窿的核部。岩体本身大多岩性均匀,变形程度不等,但岩体边缘可见较多的围岩捕虏体,并在部分情况下见及围岩的接触变质作用,反映它们的异地侵位特征。上述两带中的淡色花岗岩在矿物组成和岩石类型上表现为惊人的相似性,主要由不同比例的石英、钾长石、斜长石、黑云母(5%)、白云母、电气石和石榴石等构成二云母花岗岩、电气石花岗岩和石榴石花岗岩三大主要岩石类型。从不同地区的野外观察来看,二云母花岗岩为喜马拉雅淡色花岗岩的主体岩石类型,而电气石花岗岩和石榴石花岗岩主要以规模不等的脉体形式赋存于二云母花岗岩之中,反映前两者晚期侵位的特征。地球化学特征上,这些花岗岩具有高Si、Al、K,低Ca、Mg、Fe、Ti的特点,接近花岗岩的低共熔点组分。绝大多数淡色花岗岩具有较高的含铝指数,属于过铝花岗岩。微量元素表现为较大的变化范围,但总体上表现为富集大离子亲石元素K、Rb和放射性元素U,而不同程度亏损Ba、Th、Nb、Sr、Ti等元素。稀土元素总量总体上明显低于世界上酸性岩的平均丰度,且绝大部分表现为轻-中等程度的稀土元素分馏和不同程度的Eu负异常。传统认为,喜马拉雅淡色花岗岩是原地-近原地侵位的纯地壳来源的低熔花岗岩。但本文通过分析提出,该花岗岩可能是从一种高温的花岗岩浆演化而来,其岩浆源区的性质或成因类型目前还难以确定。该岩浆在上升侵位的过程中曾经历过大规模地壳物质的混染,并发生了高度分离结晶作用。因此,喜马拉雅淡色花岗岩首先是一种高分异型的花岗岩,是真正意义上的异地深成侵入体,而并不是原地或半原地的部分熔融体。这种以大规模地壳混染和结晶分异作用为特征的花岗岩系,在花岗岩的研究内容中还未被充分地讨论。以前根据相关信息认为这些岩石来自于沉积岩部分熔融的结论,只是较多地注意到了后期地壳混染和结晶分异作用的特征。即使这些岩石的原始岩浆将来被证明真的来源于沉积岩系的部分熔融,那以前的结论也只能说是"歪打正着"。根据形成年龄和地质-地球化学特征,本文将这些花岗岩划分为原喜马拉雅(44~26Ma)、新喜马拉雅(26~13Ma)和后喜马拉雅(13~7Ma)三大阶段。其中第一阶段对应印度-亚洲汇聚而导致的大陆碰撞造山作用,而后两个阶段同加厚的喜马拉雅-青藏高原碰撞造山带拆沉作用有关,对应青藏高原的全面隆升。根据这些淡色花岗岩的岩石与地球化学特征,我们还不能支持青藏高原存在广泛的中地壳流动的模型。相反,俯冲的高喜马拉雅岩系在深部的部分熔融及随该岩系折返而发生的分离结晶作用可很好地解释淡色花岗岩所具有的系列特征。  相似文献   

脂质体悬浮液结晶对其冻干品质影响的研究     

刘占杰  华泽钊  陶乐仁  李保国  陈建明  高申 《中国海洋大学学报(自然科学版)》2001,31(4):612-618

利用低温显微镜系统对含有不同浓度海藻糖的脂质体悬浮液 ,在不同的降温速率下的结晶现象进行显微研究 ,得出不同条件下的冰晶生长图像 ;并研究脂质体在不同的降温速率下的冻干过程 ,比较了不同降温速率下的冻干脂质体的外观和冻干脂质体复水后的囊泡粒径变化。结果表明 ,对于液体药品快速冻结后得到的冻干品质量优于慢速冻结。  相似文献