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Characterization of a sodium-regulated glutaminase from cyanobacterium Synechocystis sp. PCC 6803

science china(Life sciences) 2008年第12期51卷 1066-1075页

作者： ZHOU Jie1, ZHOU JunXia1,2, YANG HaoMeng1, YAN ChengShi1 & HUANG Fang1 1 Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, chinese academy of sciences, beijing 100093, china 2.graduate school of chinese academy of sciences, beijing 100039, china 1. Key Laboratory of Photosynthesis and Environmental Molecular Physiology Institute of Botany Chinese Academy of Sciences Beijing 100093 China 2. graduate school of chinese academy of sciences Beijing 100039 China

Glutaminase is widely distributed among microorganisms and mammals with important functions. Lit-tle is known regarding the biochemical properties and functions of the deamidating enzyme glutami-nase in cyanobacteria. In this study a putative glutaminase encoded by gene slr2079 in Synechocystis sp. PCC 6803 was investigated. The slr2079 was expressed as histidine-tagged fusion protein in Es-cherichia coli. The purified protein possessed glutaminase activity, validating the functional assign-ment of the genomic annotation. The apparent Km value of the recombinant protein for glutamine was 26.6 ± 0.9 mmol/L, which was comparable to that for some of other microbial glutaminases. Analysis of the purified protein revealed a two-fold increase in catalytic activity in the presence of 1 mol/L Na+. Moreover, the Km value was decreased to 12.2 ± 1.9 mmol/L in the presence of Na+. These data demon-strate that the recombinant protein Slr2079 is a glutaminase which is regulated by Na+ through in-creasing its affinity for substrate glutamine. The slr2079 gene was successfully disrupted in Synecho-cystis by targeted mutagenesis and the △slr2079 mutant strain was analyzed. No differences in cell growth and oxygen evolution rate were observed between △slr2079 and the wild type under standard growth conditions, demonstrating slr2079 is not essential in Synechocystis. Under high salt stress condition, however, △slr2079 cells grew 1.25-fold faster than wild-type cells. Moreover, the photosyn-thetic oxygen evolution rate of △slr2079 cells was higher than that of the wild-type. To further charac-terize this phenotype, a number of salt stress-related genes were analyzed by semi-quantitative RT-PCR. Expression of gdhB and prc was enhanced and expression of desD and guaA was repressed in △slr2079 compared to the wild type. In addition, expression of two key enzymes of ammonium assimi-lation in cyanobacteria, glutamine synthetase (GS) and glutamate synthase (GOGAT) was examined by semi-quant

关键词： cyanobacteria Synechocystis putative glutaminase enzyme activity mutagenesis salt tolerance

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Wet-chemical synthesis and characteristics of Au nanoshell

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science china Chemistry 2005年第5期48卷 431-435页

作者： LIU Zhongxin1,2, SONG Hongwei1, YU Lixin1,2, YANG Linmei1,2 & PAN Guohui1,2 1. Key Laboratory of Excited State Physics, Changchun Institute of Optics, Fine Mechanics and Physics, chinese academy of sciences, Changchun 130033, china 2. graduate school of the chinese academy of sciences, beijing 100039, china 1. Key Laboratory of Excited State Physics Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences 130033 Changchun China 2. graduate school of the chinese academy of sciences 100039 Beijing China

Gold nanoshells were prepared by an easy wet-chemical method, with Ag nanoparticles used as the templates. Transmission electron microscopy (TEM) indicated that the shells were sphere in shape, the size was homogenous, being about 20 nm, and no hard ag-glomerates were observed. The plasma resonance absorption of gold was tuned from visible to near-infrared (NIR) with the increased volume of HAuCl4. The temperature grads (?T) of the gold nanoshell hydrosol under the exposure of an 808-nm optical fiber laser with different power den-sities were measured. The highest ?T was 30℃ (5 W/cm2, irradiation area was 2 cm2). This kind of gold nanoshell hydrosol is a promising material to be used in biomedicine such as photo-thermal cancer therapy, and its special photothermal convert property will photothermally trigger drug release.

关键词： wet-chemical synthesis, Au, nanoshell, NIR absorption, photothermal conversion.

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Cloning and expression of putative ethylene receptor genes in soybean plant

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Progress in Natural science:Materials International 2007年第10期17卷 1152-1160页

作者： Xie Zongming1,2,3, Lei Gang1,2, Wuriyanghan Hada1,2, Tian Aiguo1, Zhang Jinsong1 and Chen Shouyi1(1. National Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, chinese academy of sciences, beijing 100101, china 2. graduate school of chinese academy of sciences, beijing 100039, china 3. Xinjiang academy of Agricultural and Reclamation science, Shihezi 832000, china) National Key Laboratory of Plant Genomics Institute of Genetics and Developmental Biology Chinese Academy of Sciences Beijing 100101 China graduate school of chinese academy of sciences Beijing 100039 China Xinjiang academy of Agricultural and Reclamation science Shihezi 832000 China

Ethylene plays important roles in plant growth, development, and stress responses, and ethylene receptors have been identified and studied extensively in various plant species. Here we report the cloning of four ethylene receptor genes from soybean, i.e. GmETR1, GmERS1, GmETR2 and GmEIN4. Construction of the phylogenic tree showed that GmETR1 and GmERS1 belong to subfamily I whereas GmETR2 and GmEIN4 belong to subfamily II. The four ethylene receptor genes showed different tissue-specific expression patterns in roots, stems, leaves, cotyledons, flowers, pods and seeds of soybean. These genes were differentially regulated by various abiotic stresses and plant hormones. The possible roles of the four genes in soybean plant were also discussed.

关键词： abiotic stress expression analysis ethylene receptor plant hormone soybean.

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Experimental study on phosphorus release from sediments of shallow lake in wave flume

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science china Earth sciences 2006年第z1期49卷 92-101页

作者： SUN Xiaojing,ZHU Guangwei, LUO Liancong & QIN Boqiang Nanjing Institute of Geography & Limnology, chinese academy of sciences, Nanjing 210008, china graduate school of chinese academy of sciences, beijing 100039, china 1. Nanjing Institute of Geography & Limnology Chinese Academy of Sciences Nanjing 210008 China2. Graduate School of Chinese Academy of Sciences Beijing 100039 China

Influence of wave on sediment resuspension and nutrients release from sediments, collected from Lake Taihu and Lake Chaohu, was studied in flume experiments. Under strong-wave conditions, concentrations of suspended solids (SS), total phosphorus (TP) and dissolved total phosphorus (DTP) in overlying water were increased significantly following the sediments re-suspension. During the experiments on sediments of Lake Taihu and Lake Chaohu, TP concentrations increased 6 times and 3 times, and DTP concentration increased 100% and 70% more than it in presuspension, respectively. Concentration of soluble reactive phosphorus (SRP) of experiment on sediment of Lake Taihu increased 25%. During the massive sediment suspension, the dissolved phosphorus in pore water and much of the phosphorus adsorbed by the sediment particles were released into overlying water. The phenomena in this wave flume experiment are quite similar to the situation observed in situ of Lake Taihu. The critical wave stresses of sediment re-suspension are nearly equal. The change of concentrations of SS, TP, and SRP was the same as that in situ *** study showed that concentrations of TP and SRP in lake water could be increased significantly by wave disturbance. Phosphorus release was significantly enhanced by wave disturbance at the beginning of massive sediment re-suspension, but decreased later.

关键词： shallow lakes, wave disturbance, internal release, phosphorus, wave flume experiment.

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A new class of symmetric periodic solutions of the spatial elliptic restricted three-body problem

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science china(Physics,Mechanics & Astronomy) 2009年第9期52卷 1404-1413页

作者： XU XingBo1,2 & FU YanNing1 1 Purple Mountain Observatory, chinese academy of sciences, Nanjing 210008, china 2.graduate University of chinese academy of sciences, beijing 100039, china 1. Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 China 2. graduate University of chinese academy of sciences Beijing 100039 China

We show that there exists a new class of symmetric periodic solutions of the spatial elliptic restricted three-body problem. In such a solution, the infinitesimal body is confined to the vicinity of a primary and moves on a nearly circular orbit. This orbit is almost perpendicular to the orbital plane of the primaries, where the line of symmetry of the orbit lies. The existence is shown by applying a corollary of Arenstorf's fixed point theorem to a periodicity equation system of the problem. And this existence doesn't require any restriction on the mass ratio of the primaries, nor on the eccentricity of their relative elliptic orbit. Potential relevance of this new class of periodic solutions to real celestial body systems and the follow-up studies in this respect are also discussed.

关键词： periodic orbits spatial restricted three-body problem symmetric orbits averaging

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Exploration of combined adjustment laws about IGV,stator and rotational speed in off-design conditions in an axial compressor

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中国科学：技术科学英文版 2010年第4期53卷 969-975页

作者： HU YanMing1,2 & NIE ChaoQun1 1 Key Laboratory of Advanced Energy and Power Technology,Institute of Engineeting Thermophysics,chinese academy of science,beijing 100190,china 2.graduate school of chinese academy of sciences,beijing 100190,china 1. Key Laboratory of Advanced Energy and Power Technology Institute of Engineeting Thermophysics Chinese Academy of Science Beijing 100190 China2. Graduate School of Chinese Academy of Sciences Beijing 100190 China

Experimental investigations are performed in a three-stage low-speed axial compressor with variable inlet guide vanes(IGV) and adjustable *** characteristics of the compressor,especially the efficiency and stall margin,are analyzed in design and off-design operation conditions by adjusting stagger angles of IGV and stators as well as changing the rotational *** experimental results show that the off-design performance of the multistage axial compressor is improved by restaggering of IGV and stators related to rotational *** the background of engineering applications,digital signal processing(DSP) technique is used to realize online adjustment of stagger angles according to the corresponding relations between incidence angles of rotor and rotational speed.

关键词： axial compressor IGV surge DSP techniques off-design

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Integrated precise orbit determination of Shenzhou IV unmanned spacecraft

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science china(Technological sciences) 2004年第5期47卷 518-525页

作者： L Congmin1,2, GU Yidong3, LIN Baojun3 & GUO Jiong3 1. Center for Space science and Applied Research, chinese academy of sciences, beijing 100080, china 2. graduate school of the chinese academy of sciences, beijing 100039, china 3. General Establishment of Space science and Application, chinese academy of sciences, beijing 100080, china Correspondence should be addressed to L Congmin 1. Center for Space science and Applied Research Chinese Academy of Sciences 100080 Beijing China 2. graduate school of the chinese academy of sciences 100039 Beijing China 3. General Establishment of Space science and Application Chinese Academy of Sciences 100080 Beijing China

Considering the characteristic orbit of Shenzhou IV spacecraft and the advantages and disadvantages of several types of domestic orbit measurements, a scheme of IPOD is determined, which uses GPS, SLR and USB observation data jointly plus precise ionosphere corrections to GPS observation data. IPOD system and mathematic models of OD are introduced. The results of different joint OD are analyzed using true observation data, and show that radial accuracy is better than 2 m.

关键词： Shenzhou IV unmanned spacecraft integrated precise orbit determination GPS SLR USB.

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A tentative study for the prediction of the CME related geomagnetic storm intensity and its transit time

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science china(Technological sciences) 2005年第6期48卷 648-668页

作者： ZHAO Xinhua1,2 & FENG Xueshang1,3 1. SIGMA Weather Group, Key Laboratory of Space Weather, Center for Space science and Applied Re-search, chinese academy of sciences, beijing 100080, china 2. graduate school of the chinese academy of sciences, beijing 100039, china 3. school of Geophysics and Geoinformation Systems, china University of Geosciences, beijing 100083, china 1. SIGMA Weather Group Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences 100080 Beijing China 2. graduate school of the chinese academy of sciences 100039 Beijing China 3. school of Geophysics and Geoinformation Systems China University of Geosciences 100083 Beijing China

Using 80 CME-ICME events during 1997.1―2002.9, based on the eruptive source locations of CMEs and solar magnetic field observation at the photosphere, a current sheet magnetic coordinate (CMC) system is established in order to study the propagation of CME and its geoeffectiveness. In context of this coordinate system, the effect of the eruptive source location and the form of heliospheric current sheet (HCS) at the eruptive time of CME on the geomagnetic storm intensity caused by CME and the CME’s transit time at the Earth is investigated in detail. Our preliminary conclusions are: 1) The geomagnetic disturbances caused by CMEs tend to have the so-called “same side-opposite side effect”, i.e. CMEs erupt from the same side of the HCS as the earth would be more likely to arrive at the earth and the geomagnetic disturbances associated with them tend to be of larger magnitude, while CMEs erupting from the opposite side would arrive at the earth with less probability and the corresponding geomagnetic disturbance magnitudes would be relatively weaker. 2) The angular separation between the earth and the HCS affect the corresponding disturbance intensity. That is, when our earth is located near the HCS, adverse space weather events occur most probably. 3) The erupting location of the CME and its nearby form of HCS will also affect its arrival time at the earth. According to these conclusions, in this context of CMC coordinate we arrive at new prediction method for estimating the geomagnetic storm intensity (Dstmin) caused by CMEs and their transit times. The application of the empirical model for 80 CME-ICME events shows that the relative error of Dst is within 30% for 59% events with Dstmin≤?50 nT, while the averaged absolute error of transit time is lower than 10 h for all events.

关键词： coronal mass ejections, current sheet magnetic coordinate system, geomagnetic storm intensity, transit time, prediction method.

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Geometry of Broad Line Regions of Active Galactic Nuclei

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chinese Journal of Astronomy and Astrophysics 2008年第1期8卷 50-62页

作者： Xiao-Rong Lü1 Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, chinese academy of sciences, beijing 100049 2.graduate school of chinese academy of sciences, beijing 100049 Key Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 and graduate school of chinese academy of sciences Beijing 100049

It has long remained an open question as to the geometry of the broad line region （BLR） in active galactic nuclei （AGNs）. The reverberation mapping technique which measures the response of the broad emission lines to the ionizing continuum, when combined with multiwavelength continuum fitted by sophisticated accretion disks, provides a way of probing the BLR geometry. We analyze a sample of 35 AGNs, which have been monitored by the reverberation mapping campaign. In view of energy budget, the reverberation-based BH masses are found to be in agreement with those obtained by accretion disk models in two thirds of the present sample while the reverberation mapping methods underestimate the BH masses in about one third of objects, as also suggested by CoUin et al. in a recent work. We point out that there are obviously two kinds of BLR geometry, which are strongly dependent on the Eddington ratio, and separated by the value LBol/LEdd - 0.1. These results prefer a scenario of the disk and wind configuration of the BLR and identify the Eddington ratio as the physical driver regulating the wind in the BLR.

关键词： accretion, accretion disks - galaxies active - galaxies Seyfert - quasars general

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Representation of microscale ocean wavenumber spectrum correct to the second order

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science china Earth sciences 2005年第4期48卷 549-554页

作者： YUAN Yeli2 & HUA Feng1,2,3 1. Institute of Oceanology, chinese academy of sciences, Qingdao 266071, china 2. Key Laboratory of Marine science and Numerical Modeling, State Oceanic Administration, Qingdao 266061, china 3. graduate school of the chinese academy of sciences, beijing 100039, china 1. Key Laboratory of Marine science and Numerical Modeling State Oceanic Administration 266061 Qingdao China 2. Institute of Oceanology Chinese Academy of Sciences 266071 Qingdao China 3. graduate school of the chinese academy of sciences 100039 Beijing China

In this paper, the analytical representations of four wave source functions in high-frequency spectrum range are given on the basis of ocean wave theory and dimensional analysis, and the perturbation method is used to solve the governing equations of ocean wave high-frequency spectrum on the basis of the temporally stationary and locally homogeneous scale relations of microscale wave. The microscale ocean wavenumber spectrum correct to the second order has an explicit structure, its first order part represents the equilibrium between dif- ferent source functions, and its second order part represents the contribution of microscale wave propagation.

关键词： temporally stationary and locally homogeneous, source function in high-frequency spectrum range, microscale ocean wavenumber spectrum.

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