三唑锡在柑桔上的残留动态研究

采用田间试验方法研究了三唑锡在柑桔上和土壤中的残留动态,应用ＨＰＬＣ法测定了桔皮、桔肉和土壤中的残留量。试验结果表明,三唑锡在柑桔（全果）上的半衰期为３．１～３．９ｄ,在土壤中的半衰期为６．６～１０．３ｄ。桔园喷施２０％三唑锡胶悬剂１０００倍和２０００倍液各２～３次,每次施药间隔３０ｄ,末次施药后３０、６０、９０ｄ,柑桔（全果）和土壤中的残留量均低于１．０ｍｇ／ｋｇ。     

Identification and functional expression of the mitochondrial pyruvate carrier

The transport of pyruvate, the end product of glycolysis, into mitochondria is an essential process that provides the organelle with a major oxidative fuel. Although the existence of a specific mitochondrial pyruvate carrier (MPC) has been anticipated, its molecular identity remained unknown. We report that MPC is a heterocomplex formed by two members of a family of previously uncharacterized membrane proteins that are conserved from yeast to mammals. Members of the MPC family were found in the inner mitochondrial membrane, and yeast mutants lacking MPC proteins showed severe defects in mitochondrial pyruvate uptake. Coexpression of mouse MPC1 and MPC2 in Lactococcus lactis promoted transport of pyruvate across the membrane. These observations firmly establish these proteins as essential components of the MPC.     

A mitochondrial pyruvate carrier required for pyruvate uptake in yeast, Drosophila, and humans

Pyruvate constitutes a critical branch point in cellular carbon metabolism. We have identified two proteins, Mpc1 and Mpc2, as essential for mitochondrial pyruvate transport in yeast, Drosophila, and humans. Mpc1 and Mpc2 associate to form an ~150-kilodalton complex in the inner mitochondrial membrane. Yeast and Drosophila mutants lacking MPC1 display impaired pyruvate metabolism, with an accumulation of upstream metabolites and a depletion of tricarboxylic acid cycle intermediates. Loss of yeast Mpc1 results in defective mitochondrial pyruvate uptake, and silencing of MPC1 or MPC2 in mammalian cells impairs pyruvate oxidation. A point mutation in MPC1 provides resistance to a known inhibitor of the mitochondrial pyruvate carrier. Human genetic studies of three families with children suffering from lactic acidosis and hyperpyruvatemia revealed a causal locus that mapped to MPC1, changing single amino acids that are conserved throughout eukaryotes. These data demonstrate that Mpc1 and Mpc2 form an essential part of the mitochondrial pyruvate carrier.     

猪圆环病毒2型诱导PK-15细胞产生IFN-β的信号通路研究

【目的】研究猪圆环病毒2型(porcine circovirus type2,PCV2)感染PK-15细胞后调控β-干扰素(interferon-β,IFN-β)生成的信号通路,为猪圆环病毒病的发生机理和防治提供理论基础。【方法】将PK-15细胞随机分成5组:对照组、PCV2组、BX795(TBK1/IKKε抑制剂)组、BAY 11-7082(NF-κB抑制剂)组和BX795+BAY11-7082(混合抑制剂)组。BX795组、BAY 11-7082组、BX795+BAY 11-7082组分别用0.5μmol BX795、5μmol BAY11-7082、0.5μmol BX795+5μmol BAY 11-7082预先处理1 h,然后感染PCV2。于感染后3、12、24、48和72 h收集细胞,提取RNA。用荧光定量PCR检测IFN-β、模式识别受体(TLR3、TLR9、RIG-1、MDA-5、DAI)、接头蛋白(TRIF、MyD88、Sting、MAVS、IRF3)的mRNA 含量。【结果】PCV2感染PK-15细胞后,IFN-β的mRNA 含量在48、72 h显著升高(P0.01),表明PCV2感染可以诱导PK-15细胞生成IFN-β;TLR3的mRNA 含量在48 h显著升高(P0.01),TLR9的表达量在48、72 h显著升高(P0.01);TLR3和TLR9下游的接头蛋白MyD88和TRIF的mRNA 含量在48 h显著升高(P0.01),表明PCV2激活了Toll样受体介导的NF-κB信号途径;MDA-5的mRNA 含量在48、72 h显著升高(P0.01),RIG-1的mRNA 含量在72 h显著升高(P0.01),MDA-5和RIG-1下游的接头蛋白MAVS、Sting、IRF3的mRNA 含量在48 h显著升高(P0.01),表明PCV2激活了RIG-1样受体介导的IRF3信号途径;DAI的mRNA 含量在48、72 h显著升高(P0.01),表明PCV2亦激活了DNA模式识别受体介导的IRF3信号途径;分别用BX795和BAY 11-7082抑制IRF3和NF-κB介导的信号通路,结果显示NF-κB抑制剂组的IFN-β的mRNA 含量与PCV2组相比无显著性差异(P0.05),TBK1/IKKε抑制剂组的IFN-β的mRNA 含量与PCV2组相比明显下降(P0.05),表明PCV2诱导IFN-β的产生主要由IRF3信号途径调控。【结论】PCV2感染可以诱导PK-15细胞中IFN-β表达量的上调,其上调主要与IRF3信号通路有关。     

Psychotomimesis mediated by kappa opiate receptors

The kappa opioid agonists are analgesics that seem to be free of undesired morphine-like effects. Their dysphoric actions observed with the kappa agonist cyclazocine are thought to be mediated by an action at sigma-phencyclidine receptors. The benzomorphan kappa agonist MR 2033 is inactive at sigma-phencyclidine receptors. In male subjects, the opiate-active (-)-isomer, but not the (+)-isomer, elicited dose-dependent dysphoric and psychotomimetic effects that were antagonized by naloxone. Thus, kappa opiate receptors seem to mediate psychotomimetic effects. In view of the euphorigenic properties of mu agonists, our results imply the existence of opposed opioid systems affecting emotional and perceptual experiences.     

投资宏观调控的决策模型:从区域乘数效应角度

基于经济体内不同区域的社会边际消费倾向往往不相同的现实,运用区域两分法从区域乘数效应角度研究了投资的宏观调控决策体系,构建了相应的计量模型,进行了实际应用分析。结果表明:当投资对特定子区域的乘数效果成为关注的目标时,应当采取措施提高各子区域的边际消费倾向、特定子区域的投资内流比、非特定子区域的投资外流比、期初投资流入特定子区比例,以获得投资对特定子区域乘数效果的最佳化目标。当投资对整体区域的总体乘数效果成为关注的目标时,应当采取措施提高各子区域的边际消费倾向、边际消费倾向相对较高的子区域的投资内流比、边际消费倾向相对较低的子区域的投资外流比、期初投资流入边际消费倾向相对较高子区域的比例,以获得投资对整体区域总体乘数效果的最佳化目标。该研究具有良好的理论意义和现实价值。     

Immunoglobulin structure: amino terminal sequences of kappa chains from genetically similar mice (BALB/c)

The amino terminal portion of 20 kappa chains from the highly inbred BALB/c mouse has been examined on an automatic protein sequencer. These proteins can be divided into at least nine groups (subgroups) based on sequence patterns which are so distinct that each subgroup is probably encoded by at least one germ-line gene. The subgroups of mouse kappa chains are generally quite different from those of human kappa chains.     

Mantle values of thermal conductivity and the geotherm from phonon lifetimes

A model for thermal conductivity kappa, based on phonon lifetimes obtained from infrared reflectivity, replicates experimental data at ambient conditions. The pressure and absolute temperature dependences of transport properties are accurately obtained from the Gruneisen parameter gammaTh, bulk modulus KT, and thermal expansivity alpha: The lattice contribution kappalat equals kappa298(298/T)a exp[-(4gammaTh + 1/3) integral298Talpha(theta)dtheta] with a = 0.33 for silicates (or 0.9 for MgO), and partial differential[ln(kappalat)]/ partial differentialP = (1/3 + 4gammaTh)/KT. The smaller, pressure-independent radiative contribution kapparad equals 0.0175 - 0.0001037T + (2.245T2/10(7)) - (3.407T3/10(11)), in units of watts per meter-kelvin, if Fe2+ is present. The resulting lithospheric geotherm is steep. Consequently, the mantle geotherm is hot if the low-velocity zone is anhydrous, but cold if hydrated.     

Evidence from ion chromatography experiments that met-cars are hollow cage clusters

Ion chromatography studies were performed to assess various models proposed for the structure of M(8)C(12) species, the met-cars. A laser desorption source was used to make a sequence of titanium-carbon clusters centered around Ti(8)C(12)(+). The Ti(8)C(12)(+) was determined to be a hollow cage cluster, with the dodechadron structure originally propposed termined to be a hollow cage cluster, with the dodecahedron structure originally proposed giving the best fit to experiment; cubic structures could be excluded. Collisional breakup of Ti(8)C(12)(+) yielded only Ti(7)C(12)(+) under the experimental conditions described herein, and modeling indicated that the cage structure was retained. Both Ti(8)C(11)(+) and Ti(8)C(13)(+) were made by the cluster source, and again, dodecahedral-type cage structures were consistent with experiment. The extra carbon atom in Ti(8)C(13)(+) was attached exohedrally to a single titanium atom. No evidence for an endohedral species was found.     

对江苏农村居民消费增长和投向的实证分析

从江苏农村居民消费增长和投向的研究表明 :1989— 2 0 0 0年 ,江苏农村居民的消费增长 (Δ C)呈波浪式推进 ,1991年、1994年、1996年出现了三次增长峰值 ,1999年、2 0 0 0年的消费倾向增长 ,而储蓄倾向下降。通过边际消费倾向 (MPC)和边际储蓄倾向 (MPS)的测定 ,发现在收入增长的构成中 ,消费与储蓄比为 5 .6∶ 4 .4 ,用于消费的比例下降 ,而用于储蓄的比例上升 ,1996— 1999年 ,边际消费倾向大幅下降 ,边际储蓄倾向极度增长 ,消费、储蓄的均衡格局被打破。通过对消费倾向增长年段中相邻年份的消费支出项目的比较 ,所得的差距系数显示了长期消费增长的投向和走势 ,即农村居民消费结构和变动情况。在此基础上提出了江苏农村居民消费投向的对策     

DDT Residues Absorbed from Organic Detritus by Fiddler Crabs

DDT and its metabolites accumulate in organic plant detritus estuaries and may persist there for many years. The residues appear to be most abundantly associated with particulates having diameters from 250 to 1000 microns. Detritus particles of this size are ingested by many organisms, sociated DDT residues may enter diverse food chains. Fiddler crabs Uca were fed natural detritus containing DDT residues (10 parts per million) an 11-day experiment and showed grossly modified behavior associated threefold increase in concentration of DDT residues in the muscle of the large claw.     

导入额外拷贝nifA基因对费氏中华根瘤菌HN0 1NL根圈定殖与竞争结瘤的影响

本文研究了导入额外拷贝的肺炎克氏杆菌 (Klebsiellapneumoniae)nifA基因对受体费氏中华根瘤菌 (Sinorhizobiumfredii)HN0 1在大豆根圈的定殖和竞争结瘤的影响。将HN0 1分别与带有标记基因luxAB的参照菌株HN0 1L和带有nifA基因和标记基因luxAB的重组菌株HN0 1NL按照 1∶1等量比例接种于大豆黑龙 3 3种子表面 ,在灭菌土和非灭菌土中研究其定殖动态。每一供试菌株在根圈中的比例依次于播种后第 3天、第 7天、第 1 0天、第 1 2天、第 1 4天、第 1 6天、第 2 1天和第 3 6天进行测定 ,占瘤率在播种后第 4 0天进行比较测定。盆栽实验结果表明 :导入了额外拷贝nifA基因的重组菌HN0 1NL与受体菌HN0 1和参照菌HN0 1L相比较 ,在灭菌土和非灭菌土中均表现出显著增强的大豆根圈适应性和竞争能力     

降解菌株P-2生物学特性及其降解性能研究

为降解土壤中农药残留,解决农副产品农药超标问题,采用富集培养法分离筛选出1株能够降解多菌灵的菌株P-2,研究初始pH、培养温度、接种量、外加碳源、氮源对其生长量和降解特性的影响。结果表明:该菌株能以多菌灵为碳源生长,在基础培养基中培养5d时对100mg.L-1的多菌灵降解率达60.6%,而另外加入氮源蛋白胨,可提高降解率达91%。降解多菌灵的适宜条件为温度25～40℃、pH 5.1～8.1,且降解率与菌体生长量呈正相关关系。     

斑点叉尾鮰hepcidin抗菌肽在大肠杆菌中的融合表达

通过RT-PCR从斑点叉尾鮰肝脏中克隆编码hepcidin原前体肽的基因"pIH"。与参考序列相比,显示两个氨基酸残基的变异。通过对编码hepcidin原前体肽的基因添加EcoR I和HindⅢ酶切位点,选择含"trxA"融合头的pET32a(+)作为表达质粒、E.coliBL21(DE3)作为工程菌,成功构建"pET32a-pIH"原核表达系统。阳性克隆经1 mmol.L-1IPTG诱导、在37℃培养12 h后,表达的"trxA-pIH"融合蛋白70%以上可溶。Tricine-SDS-PAGE分析表明,细胞经超声破碎后的上清通过固化金属离子亲和层析(IMAC)纯化后,可获得高纯度的目的蛋白。     

甘蓝型油菜oleosin基因片段的克隆及序列分析

以油菜(Brassica napus)基因组DNA为模板,通过设计一对特异性引物,利用多聚酶链式反应(PCR)扩增获得oleosin基因片段。将其克隆到E.coli质粒上进行序列分析。结果表明,该基因由878个碱基组成,含一个内含子,编码193个氨基酸。不计附加的18bp凝血酶切割序列,与已报道的序列相比较,核苷酸序列及推导出的氨基酸序列的同源性分别为79.20%和91.21%。推测的氨基酸序列构成的蛋白质具有oleosin的基本结构特点,包含3个结构区域:两性N末端区(anamphipathicN-terminalre鄄gion),中心疏水区(acentralhydrophobicdomain),两性C-末端区(anamphipathicC-terminaldomain)。     

Isolation and Analysis of α-Gliadin Gene Coding Sequences from Triticum durum

Three coding sequences of gliadins genes, designed as Gli2_Du1, Gli2_Du2 and Gli2_Du3, were isolated from the genomic DNA of Triticum durum accessions CItr5083. Gli2_Du1 and Gli2_Du2 contain 945 and 864 bp, encoding the mature proteins with 314 and 287 amino acid residues, respectively. Gli2_Du3 is recognized as a pseudogene due to the stop codon occurring in the coding region. The pseudogenes, commonly occurring in gliadins family, are attributed to the single base change C → T. The amino acid sequences deduced from these gene sequences were characterized with the typical structure of α-gliadin proteins, including the toxic sequences (PSQQQP). The peptide fraction PF(Y)PP(Q)is thought to be an extra unit of repetitive domain, slightly diverging from the previous report. Six cysteine residues were observed within two unique domains. Phylogenetic analysis showed Gli2_Du2 and Gli2_Du3 were closely related to the genes on chromosome 6A, whereas Gli2_Du1 seems to be more homologous with the genes on chromosome 6B.     

木薯渣残余淀粉提取与发酵酒精工艺研究

[目的]研究木薯渣残余淀粉的优化提取工艺。[方法]利用α-淀粉酶对木薯渣中残余淀粉进行提取,再将提取液与木薯粉混合进行发酵酒精试验,主要考察固液比、液化保温时间、液化pH值、液化酶用量等因素对提取得率的影响。[结果]木薯渣残余淀粉最佳提取工艺条件是：固液比1∶12,液化保温时间65 min,液化浆料pH值5.8,液化酶用量40 U/g干渣。在此条件下从木薯渣（折干计）中提取得到的液化滤液中固形物得率是60.26%（固形物中含糖64%）。[结论]该研究方法显著降低了木薯酒精生产成本,并为有效利用木薯渣提供了新的途径。     

Heat conductivity of amorphous solids: simulation results on model structures

Through numerical simulation and consideration of phonon scattering by two-level states, the heat conductivity kappa(T), where T is temperature, has been calculated on model structures. The values obtained are in good quantitative agreement with measured data on polymethylmethacrylate, epoxy, amorphous selenium, and amorphous silicon dioxide over the temperature range 0.1 to 100 K. The calculated results reproduce the plateau feature, in the range of 5 to 20 K, that is generic to the heat conductivity of amorphous solids. Two model parameters, one characterizing the degree of structural disorder and the other related to the relaxational absorption of two-level states, are identified as being responsible for the behavior of kappa(T) at T >/= 5 K. The simulation results indicate the existence of a frequency-independent phonon diffusion regime that is consistent with the minimum phonon mean-free-path hypothesis. The magnitude of the phonon diffusion constant in this regime is shown to give a reasonable quantitative account of high-temperature kappa(T) in amorphous systems.