CO_2浓度升高对宁夏枸杞苗木光合特性及生物量分配影响

为明确大气CO_2浓度升高对宁夏枸杞光合特性及生物量分配的影响,以宁夏枸杞苗木为试材,采用开顶气室(OTC)模拟自然环境大气CO_2浓度变化,设置3个CO_2浓度水平[CK(380±20μmol/mol)、TR1(570±20μmol/mol)、TR2(760±20μmol/mol)],分别于不同CO_2浓度处理90d、120d后,测定其净光合速率(P_n)、光响应曲线、CO_2响应曲线等相关指标及植株不同器官生物量。结果表明:(1)TR1及TR2下Pn于第一年处理至90d时均较CK显著升高(P0.05),且TR1处理在120d时较CK显著降低;第二年处理90d时,TR1处理较CK下降了4.77%,处理120d时TR1、TR2均高于CK,但差异不显著。(2)随着CO_2浓度升高,两年中TR1、TR2处理的胞间CO_2浓度(C_i)较CK均显著升高,处理后120d时,气孔导度(G_s)较CK均显著下降;水分利用率(WUE)在第一年处理中均无显著变化,但在第二年处理120d时,TR1、TR2均较CK显著上升。(3)处理至90d和120d时,TR1、TR2组的宁夏枸杞苗木光饱和点、CO_2饱和点均高于CK,但TR2组初始羧化效率低于CK。(4)随着CO_2浓度升高,宁夏枸杞苗木地上部分生物量分配显著增加,地下部分生物量分配显著降低。研究发现,一定时间内适宜CO_2浓度升高可促进宁夏枸杞苗木光合作用,使得其地上部分生物量分配显著提高,地下部分生物量分配显著降低;但随着处理浓度升高及处理时间延长,其光合作用有下调趋势,表现为净光合速率、气孔导度、初始羧化效率等下降。     

Mitochondrial complexes in Trypanosoma brucei: a novel complex and a unique oxidoreductase complex

African trypanosomes, early diverged eukaryotes and the agents of sleeping sickness, have several basic cellular processes that are remarkably divergent from those in their mammalian hosts. They have large mitochondria and switch between oxidative phosphorylation and glycolysis as the major pathways for energy generation during their life cycle. We report here the identification and characterization of several multiprotein mitochondrial complexes from procyclic form Trypanosoma brucei. These were identified and purified using a panel of monoclonal antibodies that were generated against a submitochondrial protein fraction and using tandem affinity purification (TAP) tag affinity chromatography and localized within the cells by immunofluorescence. Protein composition analyses by mass spectrometry revealed substantial divergence of oxidoreductase complex from that of other organisms and identified a novel complex that may have a function associated with nucleic acids. The relationship to divergent physiological processes in these pathogens is discussed.     

γ射线辐照灭菌剂量的模糊优化

γ射线辐照灭菌处理的关键性技术是辐照剂量的优化和确定。通过对照射后的SPF试验动物饲料的理化、微生物和感官指标的分析,提出γ辐照灭菌处理的模糊综合质量评价方法,进而实现对辐照剂量的模糊优化。     

电离辐射对蛋白质分子作用的量子孤波分析

本文运用量子力学方法对蛋白质分子中孤波传播的非线性动力学特征进行了探讨。研究表明：电离辐射产生的自由基对蛋白质分子的伤害将会对携带能量、信息的孤立子波传播产生较为显著的影响。     

The Analysis of Homegarden Plant Diversity at the Mongolian Household Level in Horqin Sandy Land——A Case Study in Horqin Left Wing Real Banner of Inner Mongolia

In order to show the function of agricultural protection of biodiversity at the level of homegarden, comparative analysis was operated between 20 farmer households through random sampling and farmers recommended in Horqin Left Wing Real Banner Tongliao city Inner Mongolia Autonomous Region and 10 farmer households of the Han nationality in the neighborhood. Thirty sampling plots of homegardens are investigated. The result indicates there are 100 homegarden plants in Bashou village, 84 in Hariwusu livestock farm, and 87 in Gongjihao village. It involves the cultivated and wild vegetables, fruits, and plants used for ornamental, medicine and forage. The comparative analysis of species richness demonstrates, among these villages the species richness of Bashou village is highest, while Hariwusu livestock farm is lowest. The former village contributes greatly to the conservation of plant biodiversity. These differences result from their respectively different natural conditions, homegarden areas, homegarden history, homegarden management conditions, traditional knowledge and culture understanding of homegarden manager, local farmers and herdsmen on homegarden plants.The homegarden plants from the three investigated villages are cataloged preliminary in the end of the paper.     

Trypanosoma brucei mitochondrial ribosomes: affinity purification and component identification by mass spectrometry

Although eukaryotic mitochondrial (mt) ribosomes evolved from a putative prokaryotic ancestor their compositions vary considerably among organisms. We determined the protein composition of tandem affinity-purified Trypanosoma brucei mt ribosomes by mass spectrometry and identified 133 proteins of which 77 were associated with the large subunit and 56 were associated with the small subunit. Comparisons with bacterial and mammalian mt ribosomal proteins identified T. brucei mt homologs of L2-4, L7/12, L9, L11, L13-17, L20-24, L27-30, L33, L38, L43, L46, L47, L49, L52, S5, S6, S8, S9, S11, S15-18, S29, and S34, although the degree of conservation varied widely. Sequence characteristics of some of the component proteins indicated apparent functions in rRNA modification and processing, protein assembly, and mitochondrial metabolism implying possible additional roles for these proteins. Nevertheless most of the identified proteins have no homology outside Kinetoplastida implying very low conservation and/or a divergent function in kinetoplastid mitochondria.     

X-ray structure determination of the glycine cleavage system protein H of Mycobacterium tuberculosis using an inverse Compton synchrotron X-ray source

Structural genomics discovery projects require ready access to both X-ray diffraction and NMR spectroscopy which support the collection of experimental data needed to solve large numbers of novel protein structures. The most productive X-ray crystal structure determination laboratories make extensive use of tunable synchrotron X-ray light to solve novel structures by anomalous diffraction methods. This requires that frozen cryo-protected crystals be shipped to large multi acre synchrotron facilities for data collection. In this paper we report on the development and use of the first laboratory-scale synchrotron light source capable of performing many of the state-of-the-art synchrotron applications in X-ray science. This Compact Light Source is a first-in-class device that uses inverse Compton scattering to generate X-rays of sufficient flux, tunable wavelength and beam size to allow high-resolution X-ray diffraction data collection from protein crystals. We report on benchmarking tests of X-ray diffraction data collection with hen egg white lysozyme, and the successful high-resolution X-ray structure determination of the Glycine cleavage system protein H from Mycobacterium tuberculosis using diffraction data collected with the Compact Light Source X-ray beam.     

基因枪在大鼠闭塞性血管病基因治疗中的应用

探讨利用基因枪技术转移肝细胞生长因子基因治疗大鼠肢体闭塞性血管病的可行性,构建了携带人肝细胞生长因子（HGF）基因的重组真核表达载体（pUDKH),在制备好大鼠下肢闭塞性血管病模型后,通过基因枪或肌肉直接注射法,向局部缺血部位肌肉中转移pUDKH,每只5ug(基因枪）和12ug(肌肉注射）,应用常规组织病理切片（H．E．染色）及免疫组织化学方法观察血管形成及基因表达,转移pUDKH后第10天,用基因枪和直接注射法转移的局部肌肉组织的HGF的表达明显高于转移空白质粒（pUDK)的对照组,pUDKH组可见明显的小血管新生,而pUKD组至20天时仍未观察到或仅见到极少量的新生血管,基因枪与肌肉注射两组相比血管密度无明显差异,采用基因枪直接转移pUDKH裸露质粒子肢体缺血局部的方法是可行的,转移的基因可在局部有效表达,达到促进血管形成的预期目的。     

Genomic organization and gene function in Leishmania

Sequencing of the Leishmania major Friedlin genome is well underway with chromosome 1 (Chr1) and Chr3 having been completely sequenced, and Chr4 virtually complete. Sequencing of several other chromosomes is in progress and the complete genome sequence may be available as soon as 2003. A large proportion ( approximately 70%) of the newly identified genes remains unclassified, with many of these being potentially Leishmania- (or kinetoplastid-) specific. Most interestingly, the genes are organized into large (>100-300 kb) polycistronic clusters of adjacent genes on the same DNA strand. Chr1 contains two such clusters organized in a 'divergent' manner, i. e. the mRNAs for the two sets of genes are both transcribed towards the telomeres. Chr3 contains two 'convergent' clusters, with a single 'divergent' gene at one telomere, with the two large clusters separated by a tRNA gene. We have characterized several genes from the LD1 (Leishmania DNA 1) region of Chr35. BT1 (formerly ORFG) encodes a biopterin transporter and ORFF encodes a nuclear protein of unknown function. Immunization of mice with recombinant antigens from these genes results in significant reduction in parasite burden following Leishmania challenge. Recombinant ORFF antigen shows promise as a serodiagnostic. We have also developed a tetracycline-regulated promoter system, which allows us to modulate gene expression in Leishmania.