UV-B和NO对玉米幼苗根系呼吸作用的影响

通过对玉米幼苗根系生物量、NO释放量、呼吸作用的分析测定,发现UV-B辐射能够促进根系生物量,却明显地抑制玉米幼苗根系NO的释放、交替呼吸途径活性和细胞色素呼吸途径活性,因而降低了根系的总呼吸量.NO尽管对交替呼吸运行量有抑制作用,但能够明显地促进玉米幼苗根系交替呼吸容量、细胞色素呼吸途径的呼吸容量和运行量以及总呼吸,这可能与玉米幼苗根系相对缺氧时,与根系组织中植物球蛋白协同NO对活性氧(ROS)的生成、清除和转化以及刺激通气组织的形成、供氧条件的改善有关.     

植物激素对植物生长的效应初探

本文试验了不同激素对甘薯愈伤组织生长的效应。IAA诱导产生绿色、致愈的愈伤组织,2,4-D产生黄色、松散的愈伤组织,NAA的愈伤组织居于两者之间。细胞分裂素能增加生长的有序性,促使愈伤组织致密化。生长素和细胞分裂素配合使用可加速愈伤组织的生长,2,4—D的生长效应较强,持续时间也较长,且能提高愈伤组织中分生细胞的比数,但愈伤组织的密度(mg干重/cm~3)很低。不同品种甘薯对激素的反应有明显差异。作者认为,生长是各种不同生理过程的综合表现,激素是作用于不同生理过程而对生长过程效应的;激素的受体可能缺乏专一性,同一激素可与多种受体相结合,激素一受体复合体的差异可能产生不同的激素效应。     

红芪组织培养中次生代谢产物的研究 Ⅲ.黄芪甲甙和游离氨基酸在红芪愈伤组织中含量变化的相关性

利用ＨＰＬＣ和高速氨基酸分析仪测定红芪各种愈伤组织中黄芪甲甙和游离氨基酸的含量．结果表明,黄芪甲甙含量以分化愈伤组织为最高,是未分化愈伤组织的１２ ．５ 倍,而游离氨基酸含量分化愈伤组织与未分化愈伤组织相比较表明：脯氨酸、胱氨酸、精氨酸和谷氨酸都有一定程度的降低,其中尤以脯氨酸、胱氨酸的降低幅度较大．由此推测这４ 种氨基酸可能是次生代谢产生黄芪的前体物质．     

杨树组织培养愈伤组织对水泡型溃疡病的抗性

本文研究了12个杨树无性系的组织培养愈伤组织对BotryosPhaeria dothidea的抗病性。结果表明愈伤组织抗病性与植株水平的抗病性基本一致。来自感病无性系的愈伤组织表现感病;来自抗病无性系的愈伤组织也表现抗病。愈伤组织抗病性表达受培养基的激素浓度及比例、病原菌的接种量和接种温度影响较大;而接种方法、愈伤组织继代数对之影响较小。采用2,4-D浓度为0.5mg/1和KT浓度为0.2mg/1的MS培养基诱导愈伤组织,用1mm带菌牙签进行无伤接种控制接种量,接种温度在28℃时,愈伤组织能较好地表达植株水平的抗病性。     

人参SQS基因的干扰载体构建及转化人参愈伤组织

以5年生人参为材料, 根据人参SQS基因设计正义及反义片段引物, 构建了SQS基因干扰表达载体; 利用农杆菌转化法转化人参愈伤组织, 对获得的抗性愈伤组织进行PCR检测及实时定量PCR检测, 并对抗性愈伤组织的皂苷进行HPLC分析. 实验结果表明, 与非转化人参愈伤组织相比, 转化后的愈伤组织SQS基因表达量降低, 皂苷含量有所变化. SQS是人参皂苷生物合成途径的关键酶, 抑制SQS基因的表达, 可调控人参皂苷含量变化.     

转基因水稻外植体的诱导和绿苗分化与酶带分析

本文对转报告基因水稻的种子、叶片、茎尖和处于不同发育期的幼穗进行愈伤组织的诱导。研究了最佳外植体的选择,摸索由外植体诱导而来的愈伤组织高频绿苗的再生,以及不同日龄的水稻愈伤组织过氧化物酶、脂酶、细胞色素氧化酶的同工酶条带分布的差异与再生能力的关系。     

滇紫草愈伤组织辐照和磁场效应研究初报

本文初步研究了Ｈｅ—Ｎｅ激光和磁场对滇紫草愈伤组织生长及色素形成的影响．结果表明：功率密度０．３７ｍｗ／ｃｍ２的Ｈｅ－Ｎｅ激光处理１ｈ刺激愈伤组织生长，而色素含量在２ｈ和３ｈ处理有较大提高，分别达１５．７％和２７．８％．１０ＫＧＳ场强的磁场处理１５ｍｉｎ对愈伤组织生长和色素形成均有促进，当代和第二代色素含量较高９．５％和２７．５％。色素含量提高的稳定正在进一步观察．     

滇紫草愈伤组织辐射和磁场效应研究初报

本初步研究了Ｈｅ－Ｎｅ激光和磁场对滇紫草愈伤组织生长及色素形成的影响。结果表明：功率密度０．３７ｍｗ／ｃｍ＾２的Ｈｅ－Ｎｅ激光处理１ｈ刺激愈伤组织生长，而色素含量在２ｈ和３ｈ处理有较大提高，分别达１５．７％和２７．８％。１０ＫＧＳ场强的磁场处理１５ｍｉｎ对愈伤组织生长和色素形成均有促进，当代和第二代色素含量较高９．５％和２７．５％。色素含量提高的稳定正在进一步观察。     

抗松材线虫病赤松胚性愈伤组织的维持与稳定增殖

【目的】为了研究抗松材线虫病赤松体细胞胚胎发生和植株再生,进行了抗病赤松愈伤组织培养条件的优化。【方法】以抗松材线虫病赤松胚性愈伤组织22#-1和13#-1为材料,首先在体视镜下观察胚性与非胚性愈伤组织的细胞学形态差异,然后研究激素配比、基因型、继代方式和次数对愈伤组织增殖中形态上和生物量上的影响。【结果】抗病赤松愈伤组织可分为两类:一类为胚性愈伤组织,含有胚性胚柄细胞团(embryonic suspensormass,ESM)结构,一类为非胚性愈伤组织;胚性愈伤组织维持与增殖最佳的激素组合是2.0 mg/L 6-BA和4.0mg/L NAA;不同基因型的胚性愈伤组织的增殖状况存在差异,其中抗病赤松无性系22#-1胚性愈伤组织增殖较快,无性系13#-1增殖较慢,但差异不显著;液-固与固体交替培养方式为抗病赤松胚性愈伤组织最适宜的继代增殖方式。【结论】不同的基因型增殖状况差异不显著,增殖过程应挑选胚性愈伤组织进行增殖,使用2.0 mg/L6-BA和4.0 mg/L NAA激素配比的培养基,并采用液-固与固体交替的方式培养。     

几种草坪草组织培养和植株再生的研究

以6种草坪草种子和2种草坪草愈伤组织为材料,研究了基本培养基种类和2,4-D浓度对愈伤组织诱导以及不同的细胞分裂素对分化的影响.试验结果表明,N6培养基较MS、NB培养基适合草坪草组织培养,诱导愈伤的2,4-D浓度宜采用6 mg/L,有机添加物对愈伤组织的生长有利,特别是肌醇对草坪草愈伤组织的生长有明显的促进作用.在分化培养中,不同材料所需的细胞分裂素适宜种类需要通过试验来确定.     

A mechanistic principle for proton pumping by cytochrome c oxidase

In aerobic organisms, cellular respiration involves electron transfer to oxygen through a series of membrane-bound protein complexes. The process maintains a transmembrane electrochemical proton gradient that is used, for example, in the synthesis of ATP. In mitochondria and many bacteria, the last enzyme complex in the electron transfer chain is cytochrome c oxidase (CytcO), which catalyses the four-electron reduction of O2 to H2O using electrons delivered by a water-soluble donor, cytochrome c. The electron transfer through CytcO, accompanied by proton uptake to form H2O drives the physical movement (pumping) of four protons across the membrane per reduced O2. So far, the molecular mechanism of such proton pumping driven by electron transfer has not been determined in any biological system. Here we show that proton pumping in CytcO is mechanistically coupled to proton transfer to O2 at the catalytic site, rather than to internal electron transfer. This scenario suggests a principle by which redox-driven proton pumps might operate and puts considerable constraints on possible molecular mechanisms by which CytcO translocates protons.     

黄河三角洲湿地植物根区优先流区和基质流区土壤特性分布差异

以黄河三角洲国家级自然保护区典型湿地植物盐地碱蓬根区土壤为研究对象,结合野外染色示踪实验和室内土壤性质测量实验,分析优先流区和基质流区土壤特性的分布差异,加深对湿地生态系统优先流对土壤影响的理解,对恢复湿地植被具有指导意义．结果表明:1）土壤有机碳、有机质、全氮和有效磷质量分数随着土壤深度的增加逐渐减小,土壤水质量分数随着土壤深度的增加先减小后增加,土壤全磷质量分数随土壤深度变化幅度较小．2）优先流区土壤有机碳、有机质、全氮和有效磷质量分数显著高于基质流区,两区土壤全磷质量分数不存在显著性差异．土壤深度为0~20 cm,优先流区土壤水质量分数高于基质流区;土壤深度>20~60 cm,基质流区土壤水质量分数高于优先流区,但差异均不显著．3）优先流区土壤有机碳、有机质、全氮和有效磷呈显著正相关,基质流区土壤有机碳、有机质和有效磷呈显著正相关．      

逆境绿豆幼苗呼吸、活性氧及乙烯产生关系研究

低温和渗透胁迫条件下绿豆(Phaseolus radiatus)黄化幼苗的总呼吸、细胞色素途径呼吸及抗氰呼吸速率明显上升并在到达高峰后下降,乙烯的释放速率也呈现类似的变化.实验结果表明,低温和渗透胁迫下乙烯的产生对呼吸作用有一定程度的依赖性,并且与逆境诱导的超氧阴离子自由基的产生密切相关,低温和渗透胁迫诱导的超氧阴离子自由基对绿豆黄化幼苗的呼吸速率没有明显的影响,却与呼吸商的变化密切相关,表明超氧阴离子自由基不是通过改变呼吸速率,而是通过改变呼吸作用的底物类型或底物降解途径从而影响乙烯的产生.     

Identification of the electron transfers in cytochrome oxidase that are coupled to proton-pumping

Mitochondrial cytochrome oxidase is a functionally complex, membrane-bound respiratory enzyme which catalyses both the reduction of O2 to water and proton-pumping. During respiration, an exogenous donor, cytochrome c, donates four electrons to O2 bound at the bimetallic haem alpha 3 Fe-Cu centre within the enzyme. These four electron transfers are mediated by the enzyme's haem alpha and CuA redox centres and result in the translocation of four protons across the inner mitochondrial membrane. The molecular mechanism of proton translocation has not yet been delineated, however, and in the absence of direct experimental evidence all four electron transfers have been assumed to couple equally to proton-pumping. Here, I report the effects of proton-motive force and membrane potential on two equilibria involving intermediates of the bimetallic centre at different levels of O2 reduction. The results show that only two of the electron transfers, to the 'peroxy' and 'oxyferryl' intermediates of the bimetallic centre, are linked to proton translocation, a finding which strongly constrains candidate mechanisms for proton-pumping.     

不同生态系统呼吸模型在半干旱草原生长季碳循环研究中的比较及应用

利用锡林浩特国家气候观象台涡度协方差通量观测系统记录的湍流数据和土壤温度、湿度数据, 分析2010-2012年锡林郭勒半干旱区针茅草原生态系统的呼吸过程及主要气候影响因子, 探讨以土壤温度和土壤体积比含水量(VWC)为计算参数的3种连乘形式的呼吸模型和Q₁₀呼吸模型在该生态系统的适用性, 在此基础上讨论该生态系统生长季净碳交换速率(NEE)、呼吸速率(R_eco)以及总初级生产力(GPP)的年际变化特征。该草原生态系统的呼吸作用受土壤温度和土壤含水量的共同影响, 其中土壤含水量是重要的限制因子。2010和2011年, 生长季降水量偏少, 该生态系统受到一定程度的干旱胁迫, 当土壤含水量处于12%~20%区间时, 呼吸速率随其升高而显著增加, 而当土壤含水量<12%或>20%时, 呼吸速率对其变化不敏感; 2012年降水充沛, 呼吸速率与土壤温度的变化趋势相关性更显著。4种呼吸模型的拟合结果表明, Q₁₀模型的表现(R²=0.64)优于其他3 种连乘模型。使用Q₁₀模型模拟的2010, 2011和2012年生长季呼吸作用的累积碳交换量分别为157.32, 138.75和 246.32 gC/m²。该草原生态系统在这3年生长季中均表现出较显著的碳汇功能, 净碳交换累积总量分别为−110.28, −68.79和−310.05 gC/m², 总初级生产力累积总量分别为267.52, 207.57和555.85 gC/m²。干旱胁迫对光合作用的影响大于呼吸作用, 与总初级生产力和呼吸作用相比, 净碳交换量的年际差异更明显。     

Cu_2ZnSnS_4纳米晶的合成和表征

用乙酰丙酮铜、二水醋酸锌、氯化亚锡和高纯硫分别作为反应的铜源、锌源、锡源和硫源,油胺充当反应溶剂和活性剂,采用热注入法在不同的温度和反应时间下合成出了Cu_2ZnSnS_4纳米晶体.然后,使用X射线衍射、紫外-可见分光光度计、扫描电子显微镜和透射电子显微镜等手段分别对Cu_2ZnSnS_4纳米晶体的晶格结构、吸收谱线和表面形貌进行了表征.通过对比发现,在270℃时合成出的纳米晶体比较纯净,纳米晶体颗粒的尺寸在一定反应时间内随反应时间的延长而增大.得到的产物在有机溶剂甲苯中分散性良好.这样的"墨汁"溶液在后期制备薄膜太阳能电池更有利.     

Mitochondrial response and calcium ion change in apoptotic insect cells induced by SfaMNPV

Mitochondrial responses and changes of calcium ions in apoptotic insect SL-1 cells induced by Syngrapha falcifera multiple nuclear polyhedrosis virus (SfaMNPV) are reported in this paper. By using Rhodamine 123 as a fluorescent labeling probe, flow cytometry analysis and confocal laser scanning microscope observation we observed that the mitochondrial transmembrane potential (△ψm) began to decrease in SL-1 cells at 4 h post infection and △ψm reduced continuously with the extension of virus infection. Western blotting indicated that the Bcl-2 level in the mitochondria gradually declined and was down- regulated. Cells undergoing apoptosis were found to have an elevation of cytochrome c in the cytosol and a corresponding decrease in the mitochondria, which indicated that cytochrome c was released from mitochondria into cytosol. These results suggest that mitochondrion-mediated apoptotic signal transduction pathway exists in apoptotic insect cell induced by SfaMNPV. Cytosolic free calcium ([Ca^2 ]i) concentration rapidly increased after SfaMNPV infection and the elevated calcium was tested to come partly from extracelllular calcium ion influx. Flow cytometry analysis indicated that the apoptosis in SL-1 cells was not influenced by established cytosolic calcium clamped conditions and the EGTA inhibiting calcium influx. Therefore, neither the elevation of cytosolic calcium ion nor extracellular calcium entry was the inducing factor of apoptosis, which hinted that the depletion of ER Ca^2 store contributed to SL-1 cell apoptosis induced by SfaMNPV.     

Structural insights into electron transfer in caa3-type cytochrome oxidase

Cytochrome c oxidase is a member of the haem copper oxidase superfamily (HCO). HCOs function as the terminal enzymes in the respiratory chain of mitochondria and aerobic prokaryotes, coupling molecular oxygen reduction to transmembrane proton pumping. Integral to the enzyme's function is the transfer of electrons from cytochrome c to the oxidase via a transient association of the two proteins. Electron entry and exit are proposed to occur from the same site on cytochrome c. Here we report the crystal structure of the caa3-type cytochrome oxidase from Thermus thermophilus, which has a covalently tethered cytochrome c domain. Crystals were grown in a bicontinuous mesophase using a synthetic short-chain monoacylglycerol as the hosting lipid. From the electron density map, at 2.36?? resolution, a novel integral membrane subunit and a native glycoglycerophospholipid embedded in the complex were identified. Contrary to previous electron transfer mechanisms observed for soluble cytochrome c, the structure reveals the architecture of the electron transfer complex for the fused cupredoxin/cytochrome c domain, which implicates different sites on cytochrome c for electron entry and exit. Support for an alternative to the classical proton gate characteristic of this HCO class is presented.     

Proton-coupled electron transfer drives the proton pump of cytochrome c oxidase

Electron transfer in cell respiration is coupled to proton translocation across mitochondrial and bacterial membranes, which is a primary event of biological energy transduction. The resulting electrochemical proton gradient is used to power energy-requiring reactions, such as ATP synthesis. Cytochrome c oxidase is a key component of the respiratory chain, which harnesses dioxygen as a sink for electrons and links O2 reduction to proton pumping. Electrons from cytochrome c are transferred sequentially to the O2 reduction site of cytochrome c oxidase via two other metal centres, Cu(A) and haem a, and this is coupled to vectorial proton transfer across the membrane by a hitherto unknown mechanism. On the basis of the kinetics of proton uptake and release on the two aqueous sides of the membrane, it was recently suggested that proton pumping by cytochrome c oxidase is not mechanistically coupled to internal electron transfer. Here we have monitored translocation of electrical charge equivalents as well as electron transfer within cytochrome c oxidase in real time. The results show that electron transfer from haem a to the O2 reduction site initiates the proton pump mechanism by being kinetically linked to an internal vectorial proton transfer. This reaction drives the proton pump and occurs before relaxation steps in which protons are taken up from the aqueous space on one side of the membrane and released on the other.     

细胞色素C在SAM修饰电极上的电化学行为

应用循环伏安法研究了细胞色素c在2-氨基乙硫醇自组装膜修饰金电极上的电化学行为。结果表明，细胞色素c在2-氨基乙硫醇修饰的金电极上的电子传递过程为—扩散控制的可逆反应，2-氨基乙硫醇自组装膜可用作细胞色素c电子传递的有效促进剂。依据电化学石英晶体微天平和电化学交流阻抗谱的测量结果，讨论了单分子膜的组装过程及其对促进细胞色素c电子传递的作用机制。