Genome-wide survey of putative serine/threonine protein kinases in cyanobacteria

Background: Serine/threonine kinases (STKs) have been found in an increasing number of prokaryotes, showing important roles in signal transduction that supplement the well known role of two-component system. Cyanobacteria are photoautotrophic prokaryotes able to grow in a wide range of ecological environments, and their signal transduction systems are important in adaptation to the environment. Sequence information from several cyanobacterial genomes offers a unique opportunity to conduct a comprehensive comparative analysis of this kinase family. In this study, we extracted information regarding Ser/Thr kinases from 21 species of sequenced cyanobacteria and investigated their diversity, conservation, domain structure, and evolution. Results: 286 putative STK homologues were identified. STKs are absent in four Prochlorococcus strains and one marine Synechococcus strain and abundant in filamentous nitrogen-fixing cyanobacteria. Motifs and invariant amino acids typical in eukaryotic STKs were conserved well in these proteins, and six more cyanobacteria- or bacteria-specific conserved residues were found. These STK proteins were classified into three major families according to their domain structures. Fourteen types and a total of 131 additional domains were identified, some of which are reported to participate in the recognition of signals or substrates. Cyanobacterial STKs show rather complicated phylogenetic relationships that correspond poorly with phylogenies based on 16S rRNA and those based on additional domains. Conclusion: The number of STK genes in different cyanobacteria is the result of the genome size, ecophysiology, and physiological properties of the organism. Similar conserved motifs and amino acids indicate that cyanobacterial STKs make use of a similar catalytic mechanism as eukaryotic STKs. Gene gain-and-loss is significant during STK evolution, along with domain shuffling and insertion. This study has established an overall framework of sequence-structure-function interactions for the STK gene family, which may facilitate further studies of the role of STKs in various organisms.

甘肃黄芪对多柔比星心肌病大鼠心肌组织部分基因表达的影响

目的 比较正常大鼠和多柔比星心肌病大鼠心肌组织部分基因表达谱的差异,探讨甘肃黄芪对上述基因表达谱的影响.方法 30只Wistar大鼠随机分3组:对照组即生理盐水组(n=10),多柔比星组(n=10)和黄芪+多柔比星组(n=10).分别从3组心肌组织中抽提总RNA,用Cy3,Cy5荧光标记,经逆转录合成动物来源的eDNA探针;eDNA探针与4000点基因表达谱芯片杂交,结果由软件分析表达信号.结果 共有923条基因出现差异表达,其中586条基因表达下调,337条基因表达上调.凋亡相关基因表达在多柔比星心肌病时上调;氧化和能量代谢相关基因的表达在多柔比星心肌病时下调.6个在多柔比星组上调的基因在黄芪+多柔比星组下调,8个在多柔比星组下调的基因在黄芪+多柔比星组上调,3个在多柔比星组上调的基因在黄芪+多柔比星组表达进一步增强.结论 凋亡和能量代谢障碍及免疫因素在多柔比星心肌病的发病机制中参与作用,甘肃黄芪对多柔比星诱导的心肌病大鼠的心脏保护作用是通过多基因多途径调节相关基因表达而实现的.

Determination of 30 free fatty acids in two famous Tibetan medicines by HPLC with fluorescence detection and mass spectrometric identification

A simple and sensitive high-performance liquid chromatographic (HPLC) method with fluorescence detection and mass spectrometric identification has been developed for analysis of 30 long-chain and short-chain free Fatty acids (FFAs). The fatty acids were derivatized to their esters with 1-[2-(p-toluenesulfonate)ethyl]-2-phenylimidazole-[4,5-f]-9,10-phenanthrene (TSPP) in N,N-dimethylformamide (DMF) at 90 degrees C with anhydrous K2CO3 as catalyst. A mixture Of C-1-C-30 fatty acids was completely separated within 60 min by gradient elution on a reversed-phase C-8 column. Qualitative identification of the acids was performed by atmospheric-pressure chemical ionization mass spectrometry (APCI-MS) in positive-ion mode. The fluorescence excitation and emission wavelengths were 260 and 380 nm, respectively. Quantitative determination of the 30 acids in two Tibetan medicines Gentiana straminea and G. dahurica was performed. The results indicated that the medicines contained many FFAs. Linear correlation coefficients for the FFA derivatives were > 0.9991. Relative standard deviations (RSDs, n = 6) for the fatty acid derivatives were < 3%. Detection limits (at a signal-to-noise ratio of 3:1) were 3.1-38 fmol. When the fatty acid derivatives were determined in the two real samples results were satisfactory and the sensitivity and reproducibility of the method were good.

地质环境的地球化学研究—贺“环境地质学的出现”发表30周年暨中国科学院地球化学研究所环境地球化学国家重点实验室成立10周年

1972年刘东生院土撰文发表了“环境地质学的出现”。中国科学院地球化学研究所环境地球化学国家重点实验室于1992年正式成立，刘东生院士的环境地质学学术观点聚焦于：环境地质学发展的动力源于社会需要，地球环境系统的整体性及其与人类关系的相互依存性。30年来，地质环境的地球化学研究以区域环境质量和全球环境变化两大科学问题作了基本目标，经历了调查评价，区域综合和界面机理3个发展阶段，研究重点是典型区域环境演化的发生学原理，谱系特征以及健康和生态效应，云贵高原地质环境的特殊性显示出青藏隆起对周边现代环境的影响。环境地质学以“地质学与人类”为宗旨，将在21世纪为人类谋求更多的福利。