镧在菠菜叶绿体中的分布及其对光合作用的影响

在体研究了稀土元素镧(La)对菠菜叶绿体Hill反应活力、Mg2+-ATPase和Ca2+-ATPase活性的影响,并用电感耦合等离子体质谱(ICP-MS)测定了叶绿体各亚细胞器中La的含量.实验结果表明,低(15mg·L?1)、中(30mg·L?1)浓度的LaⅢ对菠菜叶绿体Hill反应活力、Mg2+-ATPase和Ca2+-ATPase活性有明显的促进作用,而高浓度时(60mg·L?1)则表现出显著的抑制作用;叶绿体中大部分La位于光系统Ⅱ(PSⅡ)中,占叶绿体中La总量的90%左右.利用排阻色谱-紫外/电感耦合等离子体质谱联用技术(SE-HPLC-UV/ICP-MS)对La在PSⅡ中的存在点位进行了研究,发现La在PSⅡ中有两种不同的结合点位:La不仅可以部分竞争取代PSⅡ中与叶绿素结合蛋白相结合的Mg,而且还可能竞争结合到PSⅡ中Ca和Mn的结合点位上来影响光合作用效率

Chemical interactions of mercury species and some transition and noble metals towards metallothionein (Zn7MT-2) evaluated using SEC/ICP-MS, RP-HPLC/ESI-MS and MALDI-TOF-MS

National Natural Science Foundation of China [21035006, 21275120]; National Basic Research Program 973 Project [2009CB421605]The chemical affinities of three submetallomes ("Mn, Co, Ni, Cu, Cd''; "Pd, Pt, Au''; and "Hg, CH3Hg, C2H5Hg-THI'') towards metallothionein-2 (Zn7MT-2) in a physiological solution environment were evaluated using SEC/ICP-MS together with RP-HPLC/ESI-IT-MS and MALDI-TOF-MS, and followed the order: "Zn2+ Ni2+ > Mn2+, Co2+''; "Pd2+ > Au3+ > Pt2+''; and "Hg2+ > CH3Hg+ > C2H5Hg-THI''. Besides these, the structural change and composition of the CH3Hg-MT-2 complexes formed during the CH3Hg+ titration process were further investigated using CD spectroscopy, RP-HPLC/ESI-MS and MALDI-TOF-MS, indicating that linear and more hydrophobic (CH3Hg)(x)MT-2 (x = 12, 13, 14, 15, 16, 17, 18, 19 and 20) were formed. This information is important in understanding the interactions of the metals with Zn7MT-2 and their corresponding biological functions and toxicities

Distribution of lanthanum among the chloroplast subcomponents of spinach and its biological effects on photosynthesis: location of the lanthanum binding sites in photosystem II

The effects of lanthanum at different concentrations on the related photosynthetic activities of Hill reaction, Mg2+-ATPase and Ca2+-ATPase in spinach chloroplast were studied. Experimental results showed that lanthanum can increase all the activities at suitable concentration (1530 mg center dot L-1), however, it behaves toxically on them when over used (60 mg center dot L-1). To get an improved understanding of the mechanism of lanthanum effects on the photosynthesis of spinach, the different subcomponents in the chloroplast of the cultured spinach were isolated, and the content of lanthanurn in each subcomponent was determined by ICP-MS. The results obtained indicated that among these different subcomponents, about 90% out of the total chloroplast lanthanum was located in photosystem II (PS II) while there was little lanthanum in photosystem I (PS I). Moreover, size exclusion high performance liquid chromatography (SE-RPLC) coupled with online UV and ICP-MS detections was novelly used for locating lanthanum binding sites in PS II proteins for the first time. It was found that lanthanum has two binding sites in PS II: La associates with chlorophyll together with magnesium in PS II by partly replacing magnesium and also shares the common binding sites of PS II proteins together with the inorganic cofactors of calcium and manganese, influencing the process of photosynthesis

Brassica chinensis L.体内络合钝化和抗氧化酶系统协同抵御镉胁迫的机制初探

以小白菜(Brassica chinensis L.)作为模型植物,在不同浓度的Cd胁迫条件下,研究小白菜富集Cd的能力以及可能的细胞抵御机制.在200μmol·L?1Cd胁迫下,小白菜地上部分及根部Cd含量分别达到1348.3和3761.0mg·kg?1(干重);小白菜体内Cd含量与植物络合素(phytochelatins,PCs)含量成正相关,Cd浓度越高PCs的含量也越高,表明PCs络合Cd在小白菜体内Cd的解毒及耐受机制中起最主要的作用.此外,在研究Cd胁迫下小白菜地上部分丙二醛(MDA)的产生、H2O2的含量及抗氧化酶如超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、愈创木酚过氧化酶(POD)及抗坏血酸过氧化酶(APX)的活性变化的过程中发现,在5~50μmol·L?1Cd的胁迫下,酶的活性成上升趋势,有效地抵御氧化胁迫,说明抗氧化系统在小白菜对Cd的解毒中发挥作用.这些抵御机制降低了游离Cd的破坏作用,提高了对Cd的耐受能力;谷胱甘肽(GSH)在协调PCs络合钝化游离态Cd和抗氧化酶系统抵御Cd的氧化损伤过程中发挥了"枢纽"作用.这些研究结果不但为植物体内PCs的络合钝化及抗氧化系统协同抵御Cd的诱导氧化胁迫提供了实验证据,而且深化了对植物自身本能的抵御重金属污染损伤机制的理解.国家自然科学基金(批准号:20535020和20475046);; 国家高技术研究发展计划(批准号:2006AA06Z404);; 国家重大基础研究发展计划(批准号:2003CD415001)资助项

A dual-labelling strategy for integrated ICPMS and LIF for the determination of peptides

In this proof-of-concept study, a novel dual-labelling strategy for conjugating -SH and -NH(2) of a peptide was developed, in which an element tag (1,4,7,10-tetraazacyclododecane-1,4,7-trisacetic acid-10-maleimidoethylacetamide loaded with europium) and a fluorescent tag (fluorescein isothiocycanate) were employed. Its feasibility was demonstrated using HPLC-UV/ESI-MS for evaluating labelling-efficiency and HPLC-ICPMS with (153)Eu isotope dilution as well as CE-LIF for the determination of peptides.National Natural Science Foundation of China[21035006, 20775062]; 973 National Basic Research Program[2009CB421605

A chemical ''hub'' for absolute quantification of a targeted protein: orthogonal integration of elemental and molecular mass spectrometry

National Basic Research 973 Program [2014CB932004]; National Natural Science Foundation of China [21035006, 21275120]A novel element-tagged activity-based photo-cleavable biotinylated chemical ``Hub'' was designed and synthesized to orthogonally integrate ICP-MS and ESI-MS for absolute targeted-protein quantification. This tetrafunctional chemical ``hub'' allowed us to quantify a targeted protein using species-unspecific isotope dilution ICP-MS and to know which protein is being quantified using ESI-IT-MS at the same time

Photocatalytical reduction of disulphide bonds in peptides on Ag-loaded nano-TiO(2) for subsequent derivatization and determination

We reported an alternative strategy to reduce disulphide bonds in peptides with Ag-nanoparticle loaded nano-TiO(2) (Ag/TiO(2)) under UV irradiation. The feasibility of this strategy was adequately demonstrated using the model peptides oxidized glutathione, vasopressin and insulin, which contain various disulphide bonds, as well as by its application to the determination of Cd-induced phytochelatins in Phaeodactylum tricornutum.National Natural Science Foundation of China[21035006, 20775062, 20535020]; National Basic Research Program (973)[2009CB421605

X射线双星系统的探测

搜寻X射线双星并建立大规模样本是解决众多科学问题(如\"银河系中有多少黑洞X射线双星?黑洞和中子星之间有无质量间隙?球状星团中有无黑洞?\"等)的基础.爱因斯坦探针卫星拥有更灵敏的探测能力,将在运行的几年之中,预计可以发现一批新的中子星和黑洞X射线双星,研究其空间和动力学质量分布成为解决上述问题的关键.国家重点研发计划(编号:2016YFA040080X);;国家自然科学基金(编号:1133305);;中国科学院战略性先导科技专项(编号:XDA15052100,XDB23040000)资助项