北美CHIHUAHUAN荒漠11种啮齿动物种群密度季节性和周期性的比较研究

本文提出了季节性指标并用时间序列方法分析和比较了北美Chihuahuan荒漠11种啮齿动物种群密度的季节性、趋势和周期性。结果表明,研究期各年间盘尼西拉特斯颊囊鼠(C.p-enicillatus)有最显著的季节性,鹿鼠属(Peromyscus)的两个物种和伏拉瓦斯囊鼠(Pg.flav-us)的季节性最无规律;11个种群中有7个有趋势,除旗尾更格卢鼠(D.spectabilis)的种群密度呈减少趋势外,其余6个种群的密度呈增加的趋势;种群密度的周期,麦利阿姆更格卢鼠(D.merriami)是4年,曼利卡拉特斯鹿鼠(P.maniculatus)是4.5年,盘尼西拉特斯颊囊鼠(C.penicillatus)等3个种群是1年。对11个种群的比较说明,这些种群密度的季节性、趋势和周期性呈现出明显的多样化,且与它们的亲缘关系或种系发生历史无显著关系。11个种群的密度变动的多样化维持了它们在时间方面的共存。     

Polyclonal antibody against the DPV UL46M protein can be a diagnostic candidate

Background

The threat of recurring influenza pandemics caused by new viral strains and the occurrence of escape mutants necessitate the search for potent therapeutic targets. The dependence of viruses on cellular factors provides a weak-spot in the viral multiplication strategy and a means to interfere with viral multiplication.

Results

Using a motif-based search strategy for antiviral targets we identified caveolin-1 (Cav-1) as a putative cellular interaction partner of human influenza A viruses, including the pandemic influenza A virus (H1N1) strains of swine origin circulating from spring 2009 on. The influence of Cav-1 on human influenza A/PR/8/34 (H1N1) virus replication was determined in inhibition and competition experiments. RNAi-mediated Cav-1 knock-down as well as transfection of a dominant-negative Cav-1 mutant results in a decrease in virus titre in infected Madin-Darby canine kidney cells (MDCK), a cell line commonly used in basic influenza research as well as in virus vaccine production. To understand the molecular basis of the phenomenon we focussed on the putative caveolin-1 binding domain (CBD) located in the lumenal, juxtamembranal portion of the M2 matrix protein which has been identified in the motif-based search. Pull-down assays and co-immunoprecipitation experiments showed that caveolin-1 binds to M2. The data suggest, that Cav-1 modulates influenza virus A replication presumably based on M2/Cav-1 interaction.

Conclusion

As Cav-1 is involved in the human influenza A virus life cycle, the multifunctional protein and its interaction with M2 protein of human influenza A viruses represent a promising starting point for the search for antiviral agents.     

人纤溶酶原kringle 5在大肠杆菌中克隆和分泌表达

构建能够表达分泌性的人纤溶酶原kringle 5（简称hPK-5）的大肠杆菌工程菌。用PCR方法扩增获得hPK-5基因,构建原核表达载体pET-22b（＋）/hPK-5,转化大肠杆菌BL21（DE3）,经IPTG诱导表达并鉴定其免疫学活性。成功表达14kD的重组hPK-5,且约占菌体分泌性蛋白20%以上,经Western Blot分析表明其具有hPK-5的免疫抗原活性。人纤溶酶原kringle 5在大肠杆菌中BL21（DE3）获得可分泌表达。     

Determining the role of Tie-dyed1 in starch metabolism: epistasis analysis with a maize ADP-glucose pyrophosphorylase mutant lacking leaf starch

In regions of their leaves, tdy1-R mutants hyperaccumulate starch. We propose 2 alternative hypotheses to account for the data, that Tdy1 functions in starch catabolism or that Tdy1 promotes sucrose export from leaves. To determine whether Tdy1 might function in starch breakdown, we exposed plants to extended darkness. We found that the tdy1-R mutant leaves retain large amounts of starch on prolonged dark treatment, consistent with a defect in starch catabolism. To further test this hypothesis, we identified a mutant allele of the leaf expressed small subunit of ADP-glucose pyrophosphorylase (agps-m1), an enzyme required for starch synthesis. We determined that the agps-m1 mutant allele is a molecular null and that plants homozygous for the mutation lack transitory leaf starch. Epistasis analysis of tdy1-R; agps-m1 double mutants demonstrates that Tdy1 function is independent of starch metabolism. These data suggest that Tdy1 may function in sucrose export from leaves.     

E/Z-Thesinine-O-4'-alpha-rhamnoside, pyrrolizidine conjugates produced by grasses (Poaceae)

Based on direct infusion mass spectrometry we identified a novel alkaloid as a major component of perennial ryegrass (Lolium perenne). Initial mass spectral data suggested it to be a pyrrolizidine conjugate. As this class of alkaloids has not been described before from grasses, we isolated it to elucidate its structure. The isolated alkaloid proved to be a mixture of two stereoisomers. The structures of the two compounds as determined by 1D and 2D NMR spectroscopy, were E-thesinine-O-4'-alpha-rhamnoside (1) and Z-thesinine-O-4'-alpha-rhamnoside (2). These identifications were supported by the characterisation by GC-MS and optical rotation of (+)-isoretronecanol as the necine base released on alkaline hydrolysis of these alkaloids. 1 and 2 together with the aglycone and a hexoside were also detected in tall fescue (Festuca arundinacea). This is the first report of pyrrolizidine alkaloids produced by grasses (Poaceae).     

Quantitative Assessment of Murine Articular Cartilage and Bone Using X-Ray Phase-Contrast Imaging

Murine models for rheumatoid arthritis (RA) research can provide important insights for understanding RA pathogenesis and evaluating the efficacy of novel treatments. However, simultaneously imaging both murine articular cartilage and subchondral bone using conventional techniques is challenging because of low spatial resolution and poor soft tissue contrast. X-ray phase-contrast imaging (XPCI) is a new technique that offers high spatial resolution for the visualisation of cartilage and skeletal tissues. The purpose of this study was to utilise XPCI to observe articular cartilage and subchondral bone in a collagen-induced arthritis (CIA) murine model and quantitatively assess changes in the joint microstructure. XPCI was performed on the two treatment groups (the control group and CIA group, n = 9 per group) to monitor the progression of damage to the femur from the knee joint in a longitudinal study (at 0, 4 and 8 weeks after primary injection). For quantitative assessment, morphologic parameters were measured in three-dimensional (3D) images using appropriate image analysis software. Our results showed that the average femoral cartilage volume, surface area and thickness were significantly decreased (P<0.05) in the CIA group compared to the control group. Meanwhile, these decreases were accompanied by obvious destruction of the surface of subchondral bone and a loss of trabecular bone in the CIA group. This study confirms that XPCI technology has the ability to qualitatively and quantitatively evaluate microstructural changes in mouse joints. This technique has the potential to become a routine analysis method for accurately monitoring joint damage and comprehensively assessing treatment efficacy.     

Structural and metabolic transitions of C4 leaf development and differentiation defined by microscopy and quantitative proteomics in maize

C(4) grasses, such as maize (Zea mays), have high photosynthetic efficiency through combined biochemical and structural adaptations. C(4) photosynthesis is established along the developmental axis of the leaf blade, leading from an undifferentiated leaf base just above the ligule into highly specialized mesophyll cells (MCs) and bundle sheath cells (BSCs) at the tip. To resolve the kinetics of maize leaf development and C(4) differentiation and to obtain a systems-level understanding of maize leaf formation, the accumulation profiles of proteomes of the leaf and the isolated BSCs with their vascular bundle along the developmental gradient were determined using large-scale mass spectrometry. This was complemented by extensive qualitative and quantitative microscopy analysis of structural features (e.g., Kranz anatomy, plasmodesmata, cell wall, and organelles). More than 4300 proteins were identified and functionally annotated. Developmental protein accumulation profiles and hierarchical cluster analysis then determined the kinetics of organelle biogenesis, formation of cellular structures, metabolism, and coexpression patterns. Two main expression clusters were observed, each divided in subclusters, suggesting that a limited number of developmental regulatory networks organize concerted protein accumulation along the leaf gradient. The coexpression with BSC and MC markers provided strong candidates for further analysis of C(4) specialization, in particular transporters and biogenesis factors. Based on the integrated information, we describe five developmental transitions that provide a conceptual and practical template for further analysis. An online protein expression viewer is provided through the Plant Proteome Database.     

长白山阔叶红松林近22年的气候动态

长白山阔叶红松林作为典型的温带森林生态系统。其长期的气候动态状况对研究全球变化具有重要的意义。本文采用中国科学院长白山森林生态系统定位站气象观测场1982～2003年的地面常规气象观测资料,对长白山阔叶红松林的光能因子（包括年日照时数、年日照百分率）、热量因子（包括年平均气温、1月、7月月平均气温、年极端最高、最低气温、年积温）、水分因子（包括年总降水量、年最大雪深、相对湿度、年总蒸发量）、以及年平均风速与风向等气候因子进行了分析,从而得出这些因子22年的平均值及其动态变化趋势,进而为相关领域的研究提供基础资料。