固氮酶及合成氨Fe催化剂中N_2的络合位

用乙烯为探针研究了固氮酶中Ｎ２的键合位。结果表明，乙烯不能与Ｎ２在固氮酶体系中相竞争。提出Ｎ２在固氮酶中的键合位很可能是蛋白键合ＦｅＭｏ－ｃｏ笼内６Ｆｅ位的μ６（η２，ε４）和３Ｆｅ＋１Ｍｏ位的μ４（η３，ε１）方式，而不是笼口２Ｆｅ位的μ２（η２）方式，在合成氨Ｆｅ催化剂中Ｎ２的络合方式可能是μ６（η３，ε３）

Studies on Physical-Chemical Characterization of Fe-S Clusters From Nitrogenase by Spectral Technique

n-甲基甲酰胺碱度是提取高质量固氮酶铁钼辅基的关键因素之一。过量的亚甲蓝能氧化并分解铁铜铺基为含双相铁硫簇和铁硫簇固氮酶铁钼辅基和在紫外可见光谱区中均无特征吸收峰，而在320nM处却呈弱吸收峰，棕色固氮菌固氮酶和该菌的突变菌侏uW45固氮酶（缺铁钼辅基）中的非含钼的铁硫簇在紫外可见光谱区320nM和405nM处均含有特征吸收峰.Basicity of N-methylFormamide(NMF) is one of key Factors For extracting FeMo cofactor(FeMoco) with high quality From Azotobacter vinelandii nitrogenase.FeMoco shows enough capacity to supply electrons to reduce methyl viologen of oxidization state into one of the reducing state.Following methylene bule treatment of oxidization,FeMoco was oxidized and decomposed into Fe-S cluster containing double Mo(Mo,Fe2+)-and Fe-S cluster(Fe2+ FeS6).With the addition of Ferrious chelator dipyridine and thoroughly mixing to remove unstable Fe2+,FeMoco was decomposed into Fe-S cluster containing double Mo(Mo2Fe2+FeS6)-and other simple component of Fe3+ and S2-.As indicated above only FeMoco and Fe-S clusters containing double Mo were known to exhibit resemble spectral properties.They all showed a visible absorption spectrum which was Featureless with gradually decreased absorbance in the 300-600 nm.Another FeS cluster of FeMoco decomposition was only known to exhibit a weak absorption peak at 320 nm.Being extracted From Mofe protein of mutant strain UW45 in the absence of FeMoco and From iron protein of Azotobarter vinelandii respectively,both Fe-S clusters clearly appeared to have resemble spectrum of characteristic absorbance at 320 nm and 405 nm.These puzzling observation let an important conclusion of both Fe-S clusters involving in similar Fe-S strucutres From the P cluster of Mofe protein in absence of FeMoco and From Fe-S cluster of iron protein respectively,and in somewhat distinguishable Fe-S cluster of FeMoco decomposition.国家教委回国人员科研启动经费基金;国家自然科学基

The Construction of Genomic Library From Rhizobium arachis Strain L 8 3 and Hydrogen Uptake Gene Screen

以具有高吸H2活性的花生根瘤菌l8-3为出发菌株提取总dnA，经bAMHI不完全酶切后，获得20kb左右的dnA片段，按ISH-HOrOWICz和burkE方法，与具有多克隆位点的COSMIdPlAfr3克隆载体连接，经体外包装、转导E.COlIHb101，在选择培养基平板上获得1万多个重组克隆子.随机挑选22个克隆子进行分析，其中19个克隆子携带外源dnA片段，平均长度为21.4kb，文库有效克隆子数和插入dnA片段均达到建库要求.PCr筛选和生物素探针杂交初步结果显示，重组质粒中所携带的外源dnA可能含有我们所需的吸H2基因.A genomic library of the hydrogen uptake positive (hup +) strain L 8 3 of Rhizobium arachis has been constructed by using the broad host range mobilizable cosmid pLAFR 3.The cosmid pLAFR 3 containing the multiple restriction enzyme coloning sites was digested with restriction enzyme Hind Ⅲ and EcoRI, respectively, and the linear DNA of pLAFR 3 was treated with alkaline phosphorylase.The dephosphorylated pLAFR 3 was digested with restriction enzyme BamHI and the large Fragment of pLAFR 3 BamHI digested was isloated From Low point melting gel (0.3% agrose) by electrophoresis.Total DNA of Rhizobium arachis strain L 8-3 was partly digested with restriction enzyme BamHI and the 10 to 30 kb Fragments were isolated and collected.AFter being dephosphorylated with alkaline phosphorylase, the Fragment of DNA ligated with vectors.The ligated high molecular weight of DNA ligated with vectors.The colonies were selected on LB agar plates containing tetracycline.More than ten thousand clones were obtained and eighty six percent of the clones contained cosmid with insert DNA averaging 21.4 kb in length.By using the PCR screening and biotin probe hybridization, six recombinant cosmids were isolated From the genomic library.These six recombinants possibly contained complete hup genes.It is necessary For examining the expressions of hydrogen uptake activity aFter being transduced into the hup - Rhizobium .国家自然科学基

STUDIES ON TRANSFERENCE OF HYDROGENASE GENES OF RHIZOBIUM ARACHIS

通过三亲本杂交将含有花生根瘤菌吸氢基因的质粒pZ 55(Tcr)转入不吸氢的花生根瘤菌Ra 34等菌株 (Hup- ,Nif+,Apr)中 ,筛选到既具有吸氢又具有固氮能力的花生根瘤菌结合株Rz34 2。在自生和共生条件下 ,结合株均可表达高吸氢和高固氮活性。以结合株Rz34 2接种的花生植株叶片的干重比不接种的、接种受体株Ra34(Hup- )和接种对照菌株L8 3(Hup+,Nif+)的分别高 6 2 %、7 6%和 6 3% ;种子的含氮量分别高 8 9%、1 0 0 %和 6 0 % ;产量分别高 1 8 8%、1 0 5%和 1 0 7%。研究结果表明 ,以含吸氢基因的结合株接种花生能提高根瘤菌与花生的共生固氮效率 ,增加作物的产量。The hydrogen\|uptake genes were transferred into wild Rhizobium arachis Ra strains (Hup -,Nif +,Ap r)by triparental mating using pRK2013 as help plasmid.A transconjugant R.arachis Rz34\|2(Hup +,Nif +,Ap r,Tc r)which expressed high activities of hydrogenase and nitrogenase under free\|living and symbiotic state was screened.Peanut inoculation test with recipient R.arachis Ra34,transcojugant Rz34\|2 and control strain R.arachis L8\|3 (Hup +,Nif +)was carried out respectively.The results showed that,compare to treatment without inoculation\,inoculation with R.arachis Ra34 and R.arachis L8\|3,the dry weight of leaf inoculated with transconjuant Rz34\|2 increased 6.2%\,7.6% and 6.3% respectively;the N\|content of seed increased 8.8%\,10.0% and 6.0%;the output increased 18.8%\,10.5% and 10.7%.This suggested that legume plants inoculated with Rhizobium strains (Hup +)were more efficient to accumulate N and to increase its output.国家自然科学基金! (3 9770 0 70 );; 福建省自然科学基金! (B 991 0 0 0 1 )&

N-2-BINDING SITE IN NITROGENASE AND AMMONIA-SYNTHESIS WITH IRON CATALYSTS

Ethylene was used as a probe to detect the N-2-binding site in nitrogenase. It was found that ethylene couldn't compete with N-2 in the nitrogenase system. So the N-2-binding site in nitrogenase might probably be the mode of 6Fe [mu(6)(eta(2),epsilon(4))] and the mode of 3Fe + 1Mo[mu(4)(eta(3), epsilon(1))] in the cage of the protein-bonded FeMo-co, but not be the mode of dinuclear coordination occurred on the 2Fe-sites at the gap of FeMo-co. In ammonia synthesis with iron catalysts, the N-2-binding site might probably be the mode of 6Fe [mu(6)(eta(3), epsilon(3))]

广东博罗200吨/日能量自给型城市生活垃圾堆肥系统示范工程

该技术是针对我国城市生活垃圾的特点而开发的投资省、处理效率高、成本低的垃圾处理及资源化利用新技术与新工艺。该示范工程集成和优化了分选、堆肥、热解焚烧供热、气化发电、水气渣净化等多项技术。根据我国垃圾的组成及各组分物化性质的不同将垃圾的不同处理技术有机结合，在达到减容、减量和无害化目标的同时，可将处理直接成本减少到约30元/吨，资源化利用（回收、堆肥、能量利用）程度达到约85%。减少填埋重量、体积分别达到85%、95%以上

2005～2014年CERN野外台站气象观测场土壤含水量数据集

土壤水分是影响陆地–大气边界层能量和物质传输的重要因子。土壤水分含量是中国生态系统研究网络(CERN)陆地生态系统水环境长期定位观测的重要指标。截至2014年,CERN全国范围内包括农田、森林、草地、荒漠与湿地等生态类型的34个陆地生态系统台站,依据陆地水环境观测规范、质量保证与质量控制规范,设立观测样地,并开展土壤含水量的长期定位观测与数据汇交及质控工作。CERN水分分中心选取了这34个台站2005～2014年气象观测场的土壤含水量长期监测数据,通过进一步统一规范数据格式,形成了全国范围内较长时间序列的公开共享数据集,为土壤含水量时空动态的遥感反演、模型估算验证提供地面实测数据支撑

农业资源高效利用与管理技术

该课题建立了区域农业资源利用效率评价指标体系与评价模型,首次编制了中国农业生态区划方案,建立了农业资源高效利用决策支持系统,在农业资源高效利用研究的理论与方法方面取得了重要进展。系统分析了中国的农业资源态势和发展前景,提出了以县为单元的商品粮基地建设构想,综合评估了中国不同时期、不同生态区的农业资源综合生产能力和人口承载能力,总结提出了适宜不同类型区的14种农业资源高效利用优化模式与技术体系集成方案和21项节水、节地、节肥、节粮、节本的高效利用农业资源的技术创新组合方案,具有一定的推广应用价值;研究提出的藏粮于土、提高农业资源综合生产能力的相关结论和建议,对国家和地区农业资源高效利用与区域可持..