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Low-temperature magnetic properties of horse spleen ferritin

chinese Science Bulletin 2010年第27期55卷 3174-3180页

作者： TIAN LanXiang 1,2,CAO ChangQian 1,2,LIU QingSong 1,2 &PAN YongXin 1,2 1Key laboratory of the Earth’s Deep Interior,Institute of Geology and Geophysics,chinese Academy of Sciences,beijing 100029,china 2franco-chinese biomineralization and nano-structures laboratory,beijing 100029,china Key laboratory of the Earth''s Deep Interior Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China franco-chinese biomineralization and nano-structures laboratory Beijing 100029 China

The magnetic properties of the antiferromagnetic cores in ferritin are of importance in the construction and improvement of ferritin-based magnetic resonance imaging systems and their application to environmental *** this study,we carry out integrated magnetic and transmission electron microscopy analyses of horse spleen ferritin(HoSF)to understand the relationships between the magnetic behavior of HoSF and temperature,applied field and grain-size *** R-value from the Wohlfarth-Cisowski test for the investigated sample at 5 K was 0.46,indicating very weak magnetostatic interactions among the nanoparticles of *** nanoparticles of HoSF show superparamagnetic properties at room temperature,while below the blocking temperature of Tb≈12 K it has a net magnetic moment that comes from the uncompensated spins of the nanoparticle surface or *** thermal relaxation process of HoSF follows the Néel-Arrhenius *** low-temperature AC susceptibility data,we calculated the effective magnetic anisotropy energy Ea=(5.52±0.16)×10-21 J;the effective magnetic anisotropy energy constant Keff=(4.65±0.14)×10 4 J/m3 and the pre-exponential frequency factor f0 =(4.52±2.93)×1011 *** values are useful in understanding the magnetic behavior of the antiferromagnetic nanoparticles and their potential application in biomedical technology.

关键词：马脾铁蛋白低温度磁性质透射电子显微镜磁各向异性常数纳米粒子生物医学技术交流磁化率

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DMTB:A comprehensive online resource of 16S rRNA genes,ecological metadata,oligonucleotides,and magnetic properties of magnetotactic bacteria

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chinese Science Bulletin 2011年第6期56卷 476-478页

作者： LIN Wei1,2, LI Bi1,2 & PAN YongXin1,2 1 Paleomagnetism and Geochronology laboratory, Key laboratory of the Earth’s Deep Interior, Institute of Geology and Geophysics, chinese Academy of Sciences, beijing 100029, china 2 France-china Bio-Mineralization and nano-structures laboratory, Institute of Geology and Geophysics, chinese Academy of Sciences, beijing 100029, china Paleomagnetism and Geochronology laboratory Key Laboratory of the Earth"s Deep Interior Institute of Geology and Geophysics Chinese Academy of Sciences France-china Bio-Mineralization and nano-structures laboratory Institute of Geology and Geophysics

Magnetotactic bacteria (MTB) are of interest in microbiology, biomineralization, advanced magnetic materials, and bio-geo-sciences because of their ability to form highly ordered intracellular magnetic minerals. Great strides for MTB studies have been made in the past four decades. In this paper we complied the first internet-accessible database for MTB, Database of Magnestotactic Bacteria (DMTB). It contains information of 16S rRNA gene sequences, corresponding ecological metadata, oligonucleotides, and magnetic properties of MTB. The comprehensive information contained in DMTB will provide a very useful data resource for researchers from different disciplines. The website of DMTB is at http://***/.

关键词： rRNA基因序列趋磁细菌 16S 网上资源寡核苷酸磁学性质生态磁性材料

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Cesium accumulation by bacterium Thermus sp. TibetanG7:hints for biomineralization of cesium-bearing geyserite in hot springs in Tibet,china

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chinese Science Bulletin 2007年第19期52卷 2680-2686页

作者： WANG HaiLei1,2,3, ZHENG MianPing1,2,3 & HUANG XiaoXing4 1 Institute of Mineral Resources, chinese Academy of Geological Sciences (CAGS), beijing 100037, china 2 R&D Center for Saline Lake and Epithermal Deposits, CAGS, beijing 100037, china 3 Open laboratory of Saline Lake Resourses and Environment, CAGS, beijing 100037, china 4 laboratory of Microbial Resources, Institute of Microbiology, chinese Academy of Sciences, beijing 100081, china Institute of Mineral Resources Chinese Academy of Geological Sciences (CAGS) Beijing China R&D Center for Saline Lake and Epithermal Deposits CAGS Beijing China Open laboratory of Saline Lake Resourses and Environment CAGS Beijing China laboratory of Microbial Resources Institute of Microbiology Chinese Academy of Sciences Beijing China

The bacterium Thermus sp. TibetanG7, isolated from hot springs in Tibet, china, was examined for the ability to accumulate cesium from solutions. Environmental conditions were simulated and the effects of pH, K+, Na+ and K+-regimes were then studied to determine the possible role of the bacterium in the formation of cesium-bearing geyserite around these hot springs. In despite of the inhibition of K+ and Na+, the bacterium Thermus sp. TibetanG7 revealed noticeable accumulation of cesium from solutions, with maximum accumulations of 53.49 and 40.41 μmol Cesium/g cell dry weight in Na+ and K+ inhibition experiments, respectively. The accumulation of cesium by this microorganism is rapid, with 40%―50% accumulated within the first 5 min. K+-deficient cells showed a much higher capacity of cesium accu- mulation compared with K+-sufficient cells. It is evident that the bacteria within the genus thermus play a significant role in the cesium assembly. The formation of cesium-bearing geyserite is also considered.

关键词：铯元素沉积物硅华生物矿化

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Low-temperature magnetic properties of horse spleen ferritin

Low-temperature magnetic properties of horse spleen ferritin

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中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： TIAN LanXiang~(1,2),CAO ChangQian~(1,2),LIU QingSong~(1,2) & PAN YongXin~(1,2*) 1 Key laboratory of the Earth’s Deep Interior,Institute of Geology and Geophysics,chinese Academy of Sciences,beijing 100029,china 2 franco-chinese biomineralization and nano-structures laboratory,beijing 100029,china

The magnetic properties of the antiferromagnetic cores in ferritin are of importance in the construction and improvement of ferritin -based magnetic resonance imaging systems and their application to environmental *** this study,we carry out integrated magnetic and transmission electron microscopy analyses of horse spleen ferritin(HoSF)to understand the relationships between the magnetic behavior of HoSF and temperature,applied field and grain-size *** R-value from the Woh1-farth -Cisowski test for the investigated sample at 5 K was 0.46,indicating very weak magnetostatic interactions among the nanoparticles of *** nanoparticles of HoSF show superparamagnetic properties at room temperature,while below the blocking temperature of T≈12 K it has a net magnetic moment that comes from the uncompensated spins of the nanoparticle surface or *** thermal relaxation process of HoSF follows the Neel-Arrhenius *** low-temperature AC susceptibility data,we calculated the effective magnetic anisotropy energy E=(5.52±0.16)×l0J;the effective magnetic anisotropy energy constant K=(4.65±0.14)×l0 J/m and the pre-exponential frequency factor f=(4.52±2.93)×*** values are useful in understanding the magnetic behavior of the antiferromagnetic nanoparticles and their potential application in biomedical technology.

关键词： horse spleen ferritin superparamagnetic low temperature magnetic properties pre-exponential frequency factor

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In vivo and in vitro biomineralization in the presence of the inner-shell film of pearl oyster

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Acta Oceanologica Sinica 2011年第1期30卷 87-93页

作者： YAN Zhenguang MENG Wei LIU Zhengtao YANG Suwen LIU Xiaojun SUN Juan XIE Liping ZHANG Rongqing Institute of Marine Biotechnology Department of Biological Sciences and BiotechnologyTsinghua University Beijing 100084 China chinese Research Academy of Environmental Sciences Beijing 100012 China Protein Science laboratory of the Ministry of Education Tsinghua University Beijing100084 China

The inner shell surface is the biomineralization site in shell formation and an inner-shell film covers it. This surface is composed of two regions： an outer calcitic region and an inner aragonitic region. In this study, some amalgamated calcite crystals were found in the calcitic region and some aragonitic ＂imprints＂ were found in the central part of the aragonitic region. The ＂imprints＂ are probably the trace of mantle cells that adhered to the inner shell surface when the shell was produced. Furthermore, to build a novel in vitro biomineralization system, the inner-shell film was detached from the shell and introduced to the calcitic crystallization solution. Crystallization experiments showed that nacre proteins could induce aragonite crystals in the novel system but inhibited calcite growth in the absence of the inner-shell film. These data suggested that the inner-shell film may induce aragonite growth in vivo by combining nacre proteins.

关键词： biomineralization inner shell surface inner-shell film nacre Pinctada fucata

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A comparative study of magnetic properties between whole cells and isolated magnetosomes of Magnetospirillum magneticum AMB-1

A comparative study of magnetic properties between whole cel...

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中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： LI JinHua~(1,2,3),PAN YongXin~(1,3*),LIU QingSong~(3,4),QIN HuaFeng~4,DENG ChengLong~4, CHE RenChao~5 & YANG XinAn~5 1 Key laboratory of the Earth’s Deep Interior,Institute of Geology and Geophysics,chinese Academy of Sciences,beijing 100029,china 2 Graduate University of chinese Academy of Sciences,beijing 100049,china 3 franco-chinese biomineralization and nano-structures laboratory,beijing 100029,china 4 State Key laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,chinese Academy of Sciences,beijing 100029,china 5 beijing National laboratory for Condensed Matter Physics,Institute of Physics,chinese Academy of Sciences,beijing 100080,china

The magnetic properties of magnetosome magnetite are of interdisciplinary interest because magnetosomes are potential carriers of natural remanent magnetization and paleoenvironment,as well as novel nano-biomaterials in biotechnological and biomedical *** carried out magnetic and electron transmission microscopy analyses of fresh Magnetospirillum magneticum AMB-1 whole cells and isolated *** revealed that AMB-1 synthesized single-domain magnetite magneto-somes, which are arranged in the form of linear fragmental *** distinct differences of magnetic properties between these two samples can be faithfully interpreted in terms of spatial arrangement of magnetosomes and magnetostatic *** the whole cells,the strong intra-chain interactions and weak inter-chain interactions generate behaviors of non-interacting uniaxial single-domain ***δ-ratio is 3.0 and passes the Moskowitz *** contrast,the isolated magnetosome sample has reduced values of coercivity andδ-ratio(1.5),due to increasing three-dimensional magnetostatic interactions and collapse of magnetosome *** observations provide useful insights into applications of the biogenic magnetite(magnetosomes)in magnetic nano-materials and magnetofossils in the paleomagnetic and environmental magnetism.

关键词： Magnetospirillum magneticum AMB-1 isolated magnetosomes hysteresis loop FORC Verwey transition Moskowitz test

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DMTB:A comprehensive online resource of 16S rRNA genes,ecological metadata,oligonucleotides,and magnetic properties of magnetotactic bacteria

DMTB:A comprehensive online resource of 16S rRNA genes,ecolo...

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中国科学院地质与地球物理研究所第11届（2011年度）学术年会

作者： LIN Wei~(1,2),LI Bi~(1,2) & PAN YongXin~(1,2) 1 Paleomagnetism and Geochronology laboratory,Key laboratory of the Earth’s Deep Interior,Institute of Geology and Geophysics,chinese Academy of Sciences,beijing 100029,china 2 France-china Bio-Mineralization and nano-structures laboratory,Institute of Geology and Geophysics,chinese Academy of Sciences,beijing 100029,china

Magnetotactic bacteria(MTB) are of interest in microbiology,biomineralization,advanced magnetic materials,and bio-geo-sciences because of their ability to form highly ordered intracellular magnetic *** strides for MTB studies have been made in the past four *** this paper we complied the first internet-accessible database for MTB,Database of Magnestotactic Bacteria(DMTB).It contains information of 16S rRNA gene sequences,corresponding ecological metadata,oligonucleotides, and magnetic properties of *** comprehensive information contained in DMTB will provide a very useful data resource for researchers from different *** website of DMTB is at http://***/.

关键词： magnetotactic bacteria biomineralization database

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Localization of calmodulin and calmodulin-like protein and their functions in biomineralization in P. fucata

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Progress in Natural Science:Materials International 2008年第4期18卷 405-412页

作者： Zi Fang a, Zhenguang Yan a, Shuo Li a, Qin Wang a, Weizhong Cao a, Guangrui Xu a, Xunhao Xiong a, Liping Xie a,b, Rongqing Zhang a,b, a Institute of Marine Biotechnology, Department of Biological Science and Biotechnology, Tsinghua University, beijing 100084, china b Protein Science laboratory of the Ministry of Education, Tsinghua University, beijing 100084, china Institute of Marine Biotechnology Department of Biological Science and Biotechnology Tsinghua University Beijing 100084 China Protein Science laboratory of the Ministry of Education Tsinghua University Beijing 100084 China

Calmodulin (CaM) and calmodulin-like protein (CaLP) are two proteins involved in biomineralization. Their localizations in Pinct- ada fucata mantle epithelia were studied by Western blot (WB) analysis of the nuclear/cytosol fraction of primary cultured P. fucata mantle cells and immunogold electron microscopy. The results showed a completely different distribution of these two proteins at the subcellular level. CaM was distributed throughout both the nucleus and cytoplasm of the mantle epithelium but CaLP was distributed only in the cytoplasm. The functions of these two proteins in biomineralization were investigated by shell regeneration. During this pro- cess, the expressions of CaM and CaLP were greatly enhanced in different organelles of the mantle epithelium. Overexpression of these two proteins and a mutant of calmodulin-like protein (M-CaLP) that lacks an extra C-terminal tail in MC3T3-E1 promoted the mRNA expression of osteopontin, a biomineralization marker for osteoblasts. All of the results indicated that CaM and CaLP have completely different distributions in the mantle epithelium and affect the biomineralization process at different levels. The extra C-terminal tail of CaLP is important for its functions in biomineralization in P. fucata.

关键词： Pinctada fucata Calmodulin Calmodulin-like protein Immunogold electron microscopy

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Magnetic characterization of noninteracting,randomly oriented,nanometer-scale ferrimagnetic particles

Magnetic characterization of noninteracting,randomly oriente...

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中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： Changqian Cao,Lanxiang Tian,Qingsong Liu,Weifeng Liu,Guanjun Chen, and Yongxin Pan 1 Paleomagnetism and Geochronology laboratory,Key laboratory of the Earth’s Deep Interior,Institute of Geology and Geophysics,chinese Academy of Sciences,beijing,china. 2 Also at France-china Bio-Mineralization and nano-structures laboratory,Institute of Geology and Geophysics,chinese Academy of Sciences,beijing,china. 3 Also at Graduate University of chinese Academy of Sciences,beijing, china. 4 State Key laboratory of Microbial Technology,School of Life Sciences,Shandong University,Jinan,china.

[1]Studying the magnetic properties of ultrafine nanometer-scale femmagnetic particles (<10 nm)is vital to our understanding of superparamagnetism and its applications to environmental magnetism,biogeomagnetism,iron b...

[1]Studying the magnetic properties of ultrafine nanometer-scale femmagnetic particles (biomineralization,and biomedical ***,magnetic properties of the ultrafine nanometer-sized femmagnetic grains are very poorly constrained because of ambiguities caused by particle magnetostatic interactions and unknown size *** resolve these problems,we synthesized magnetoferritins using the recombinant human H chain ferritin(HFn). These femmagnetic HFn were further purified through size exclusion chromatography to obtain monodispersed ferrimagnetic *** electron microscopy revealed that the purified ferrimagnetic HFn are monodispersed and each consists of an iron oxide core(magnetite or maghemite)with an average core diameter of 3.9±1.1 nm imbedded in an intact protein *** R value of the Wohlfarth-Cisowski test measured at 5 K is 0.5,indicating no magnetostatic *** saturation isothermal remanent magnetization acquired at 5 K decreased rapidly with increasing temperature with a median unblocking temperature of 8.2 *** preexponential frequency factor f determined by AC susceptibility is(9.2±7.9)×*** extrapolated M/M and B/B at 0 K are 0.5 and 1.12,respectively,suggesting that the ferrimagnetic HFn cores are dominated by uniaxial *** calculated effective magnetic anisotropy energy constant K=1.2×10 J/m,which is larger than previously reported values for bulk magnetite and/or maghemite or magnetoferritin and is attributed to the effect of surface *** data provide useful insights into superparamagnetism as well as biomineralization of ultrafine ferrimagnetic particles.

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A study of the microbial mineralization in submarine black smoker chimneys from the Okinawa Trough

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Acta Oceanologica Sinica 2009年第2期28卷 87-95页

作者： FENG Jun LI Jianghai CHU Fengyou National Earthquake Response Support Service China Earthquake Adiministration Beijing 100049 China School of Earth and Space Sciences Peking University Beijing 100871 China Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 China

Large amounts of microfossil records discovered in the seafloor black smoker chimney are reported from the Okinawa Trough. They are well preserved and can be divided into four types of filamentous microfossils. It suggests that the fossils may be derived from sulfur or iron oxidation chemolithotrophic prokaryotes and fungi. Based on the comparison studies of the microbial mineralization processes, two steps of biomineralization were hypothesized：（1） biology controlled mineralization; and （2） biology induced mineralization. At the early stage of the mineralization, the biology controlling mineralization is dominating; at the later stage, the biology inducing mineralization is the main mechanism. The composition of the fluids and the species of the microbes will determine the types of the minerals formed.

关键词： microfossils biomineralization black smoker Okinawa Trough

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