UPLC-MS-Based Metabolomic Study of Streptomyces Strain HCCB10043 Under Different pH Conditions Reveals Important Pathways Affecting the Biosynthesis of A21978C Compounds

The A21978C family of compounds includes precursors of daptomycin, an important antibiotic for the treatment of diseases infected by Gram-positive resistant bacteria. Focusing on these valuable compounds, the differences in metabolites obtained with or without pH control in their producing strain Streptomyces parvus HCCB10043 were investigated by comparative metabolomics analysis based on UPLC-TOF-MS technology. According to principal component analysis, there were fourteen biomarker compounds selected under the two pH culture conditions. The ten known compounds were divided into two types: a glycoside family participating in the primary metabolism (daidzein, glycitein, genistein, and soyasaponin Bb) and a peptide family of secondary metabolites (valistatin, bestatin, 3-amino-2-hydroxy-4-phenylbutanoylvalylisoleucine, and arylomycins A2, A4, and A5). Through orthogonal partial least squares-discriminant analysis, three compounds, soyasaponin Bb and arylomycins A2 and A4 were identified as the most relevant compounds to A21978C1-3 production, the glycolytic pathway, and the NRPS synthesis pathway. The competitive relationship between arylomycin and A21978C was verified. These results have demonstrated the usefulness of the metabolomic strategy based on UPLC-MS in studying significant metabolic changes in actinomycetes. Moreover, this metabolomic strategy can provide new ideas and guidance for the regulation and improvement of secondary metabolites production.     

Broadband excitation pulses for high‐field solid‐state nuclear magnetic resonance spectroscopy

In nuclear magnetic resonance spectroscopy, experimental limits due to the radiofrequency transmitter and/or coil means that conventional radiofrequency pulses (“hard pulses”) are sometimes not sufficiently powerful to excite magnetization uniformly over a desired range of frequencies. Effects due to nonuniform excitation are most frequently encountered at high magnetic fields for nuclei with a large range of chemical shifts. Using optimal control theory, we have designed broadband excitation pulses that are suitable for solid‐state samples under magic‐angle‐spinning conditions. These pulses are easy to implement, robust to spinning frequency variations, and radiofrequency inhomogeneities, and only four times as long as a corresponding hard pulse. The utility of these pulses for uniformly exciting ¹³C nuclei is demonstrated on a 900 MHz (21.1 T) spectrometer. Copyright © 2012 John Wiley & Sons, Ltd.     

Construction of mononuclear transition metal(II) complexes with bi- and tridentate,neutral hydrazone ligands with a quinoxaline hub

A series of Co(II), Ni(II), Cu(II), and Zn(II) complexes of bi- and tridentate hydrazones were prepared. Ligands L¹ and L² were synthesized by the condensation of 2-mercapto-3-hydrazinoquinoxaline with 2-hydroxy-3-formylquinoline and 3-acetylcoumarin, respectively. The compounds were characterized by various spectro-analytical techniques and magnetic moment studies. The complexes are found to be monomeric and non-electrolytes. In these complexes, [CuL¹Cl₂] has square pyramidal geometry and others have octahedral. The copper complexes are electrochemically active in the applied potential range.     

On the two methods of kinetic theory of ECRM

The kinetic theory based on the expansion of local field in the guiding center coordinate system, presented by paper[1]–[3], has successfully developed into a theoretical system. The mathematical background and physical explanation of setting up the guiding center coordinate system is expounded in the paper. By using the methods of the guiding center and waveguide coordinate systems respectively, the same dispersion equations for interaction of an axially symmetrical single momentum electron beam with TE_mn field in the circular waveguide are rigorously derived. A number of mistakes in paper[4] are indicated as well.     

HT—6M闭环反馈平衡控制系统

本文描述HT-6M托卡马克装置闭环反馈平衡控制系统的结构组成,通过对各个环节的简化,得到了有效实用的数学模型,进而分析了系统稳态和动态性能。实验结果表明,该系统运行可靠;并且,将等离子体环水平位移控制在2mm以内。     

自聚焦透镜的薄透镜等效系统

本文分析了自聚焦透镜的成象特性,提出了用薄透镜系统等效自聚焦透镜的方法,这种方法给用几何作图法和解析法求解物象关系带来了很大方便。     

描述高自旋体系的密度算符方法

提出了一种描述高自旋弱偶合体系NMR实验谱的密度算符方法,给出了高自旋体系密度算符在自旋偶合作用下的演化公式。以氘核(²D)为例,计算了重聚INEPT和同核COSY实验谱。     

一种动态实时的遥感专题应用系统定制框架

遥感专题应用系统广泛用于遥感影像的加载、分析、专题提取、出图等.为实现遥感专题应用系统动态、实时和可扩展的定制化开发,设计了一套基于组件的遥感专题应用系统定制框架：定义了组件划分方式,将专题系统划分为功能类组件和容器类组件,建立了组件属性和组件间的关系;采用XML文件描述遥感专题应用系统中的组件,并提供从XML到遥感专题应用系统的解析方法;设计了遥感专题应用系统定制平台,提出一种动态实时的软件设计方法,可以“所见即所得”地定制遥感专题应用系统,并将其保存为XML文件.采用该定制平台定制的多个专题系统已应用于相关部门.该框架为快速高效定制遥感专题应用系统提供了一种新的开发设计模式,降低了遥感数据在多行业应用的技术门槛,减少重复性开发工作.     

线性二次型最优控制的并行算法和软件

构造了线性二次型最优控制的并行算法，介绍了这个并行算法在武汉大学“ＷＵＤＰ９１”并行分布式处理系统上试算的数值应用软件的框图．本软件适用于既定动态系统的平衡问题．对于经济系统，可通过政策控制变量来调节和改善其状态和响应．对于自治系统可找出最优控制使得消耗函数达到最小值．通过对一系列例子进行试算，结果证实，所构造的并行算法和相应的数值软件是有效的，其加速比约为７．     

稀土对小麦（Triticum aestivum）体内光合和呼吸速率及磷酸化功能的影响

以适当浓度稀土溶液处理小麦后，其光合和氧化磷酸化的磷氧比（Ｐ／Ｏ）、光合控制（Ｐｃ）、呼吸控制（ＲＣ）、状态３．４光合和呼吸速率（Ｓ３．Ｓ４）与对照样比均无显著性差异。状态２（Ｓ２）光合和呼吸速率提高，差异极显著。说明小麦用最适浓度稀土处理后，对其光合和呼吸的磷酸化机构和功能膜影响不大，但显著促进了光合和呼吸速率（Ｓ２），从而促进了电子传递链的活性，使ＡＴＰ形成量增加。