生物基化学品生产展望

生物基化学品未来市场可观 工业生物技术正在渗透到化学品和燃料市场,这缘于生产过程的改进、较廉价的经济性和客户的驱动。然而,从实验室和中试规模到商业化生产这个过程极为不易,并且需要较大的投入。     

利用合成气生产生物基醇类化学品的研究进展

以合成气为底物生产乙醇、丁醇、己醇等生物基醇类化学品可以降低原料成本,减轻对化石燃料的依赖,推动碳中和目标的实现。概述了产乙酸菌中能够利用合成气的Wood-Ljungdahl途径及该过程中产乙酸菌的能量节约机制,综述了产乙酸菌遗传操作工具的发展及代谢工程改造进展。大量研究揭示了发酵条件（如温度、pH、金属离子、有机氮源、硝酸盐等）对产乙酸菌生长及醇类产物合成具有复杂的影响。气体成分及气液传质效率也是影响合成气利用的重要因素。另外,指出了利用合成气生产生物基醇类化学品现存的瓶颈问题,并展望了未来的研究方向,包括开发产乙酸中的高效基因编辑方法,在模式菌株中构建合成气利用途径、优化温度、pH、反应器设计及利用廉价培养基进行发酵。     

轮廓形态测量法在生物分类应用中的研究进展

本文阐述了形态测量学中一类重要的研究方法——轮廓形态测量法的基本概念和发展,总结了轮廓形态测量法在生物分类学研究中的应用,将轮廓形态测量法与另一类重要的形态测量学方法——标点法进行了比较,分析了这两类方法各自的优势和局限性,展望了轮廓形态测量法在昆虫分类学研究中的应用前景。     

几何形态测量法在生物形态学研究中的应用

形态分析是生物系统学及其多样性研究中很重要的一部分。随着统计学的发展,我们可以对非常复杂的数据进行分析,这在客观上导致了多变量形态测量的出现。在20世纪80年代,在数据收集和分析上产生了重要突破——标点和标点相对位置的几何信息的匹配,从而可以将多变量分析的标点集叠加到生物原始图上,它不仅仅是生成散点图,而是试图客观反映生物的形态性状。这项研究被称为几何形态测量法(geometricmorphometrics),Rohlf和Marcus(1993)称其为形态测量方法上的一次革命。文章简要介绍了该方法。     

基因编码型生物传感器在微生物细胞工厂中的应用进展

合成生物学的迅猛发展推动了微生物细胞工厂中多种复杂化学品的生物合成,但仍存在产量低、生产效率不高等诸多问题。基因编码型生物传感器可以感知细胞内外代谢物浓度及外界环境的波动,产生可测量的信号输出或调控通路中的基因表达水平,具有成本低、操作简单、可再生等优点。目前,基因编码型生物传感器已经成为合成生物学和代谢工程的重要组成部分,是微生物细胞工厂中代谢动态调控及理想表型进化/筛选的强大工具。概述了基因编码型生物传感器的组成及工作原理,重点介绍了基因编码型生物传感器在微生物代谢动态调控及高通量筛选中的最新研究进展,就基因编码型生物传感器设计与构建过程中面临的挑战进行探讨,并展望了其今后的发展方向。     

生物基化学品生产合成橡胶技术正在脱颖而出

虽然生物基化学品仍然处于发展阶段,但是生物质原料转化成能源已经是一个成熟的技术,生物基化学品（尤其是生物基异丁烯、生物基丁二烯、生物基异戊二烯和生物基乙烯）生产合成橡胶技术正在脱颍而出。     

超声波在生物发酵工程中的应用

一定强度的超声波作用于发酵过程中缩短发酵时间,改善生物反应条件,提高生物产品的质量和产量,微弱超声可用于在线检测某些发酵过程参数,本简要介绍了超声波作用于生物发酵过程的基本原理,并详细讨论了超声波在遗传育种 ,改善发酵工艺有发酵产物的提取与分离,发酵产物浓度的在线检测等方面的主要应用。     

2013生物基化学品 (Biobased Chemicals) 专刊序言

生物基化学品是生物经济和生物制造的核心内容之一。本专刊综述了国内外生物基化学品的重要研究进展,包括：丁二酸、己二酸、乳酸、3-羟基丙酸、葡萄糖二酸、甘油、木糖醇、高级醇、乙烯等生物基化学品的代谢工程和发酵调控,直接利用木质纤维素生产生物基化学品的菌株构建,生物基乳酸的衍生和生物转化技术,生物基化学品的盐析萃取分离纯化技术等。同时,本专刊也包括了国内学者在丁二酸、D-甘露醇、苹果酸、5-氨基乙酰丙酸、1,3-丙二醇和丁醇方面的研究论文。     

细胞薄层培养在植物激素调节形态发生研究中的应用

从外源激素对形态发生的调节、植物激素的作用机制、形态发生的内源激素动态等方面概述了细胞薄层培养在植物激素诱导与调节形态发生研究中的应用进展,并对其在植物信号转导、玻璃化现象的发生机制、离体再生障碍的克服等研究领域的发展前景和尚存在的问题作了讨论。     

生物过程工程进展

中国是工业生物技术大国,发酵装置体积1000万立方米．居世界第一。在工业生物技术上游领域（细胞工程、基因工程等）和世界先进水平差距较小,但在工业生物技术的过程科学基础研究方面与国外有较大差距．尤其是过程放大原理和方法方面。在“973”计划的支持下,我国工业生物技术在过程科学领域取得了下述重要进展。     

Analysis of ion channels by modeling the osmotic effects of weak acids and bases

Summary This paper describes computer programs which may be used to identify and analyze cation and anion channels. Weak acids are used to increase intracellular proton concentrations and by so doing to promote the exchange of osmotically active cations with protons. The time course of cation exchange is readily identified from the changes in cell volume which accompany the net changes in osmotically active cations. Weak bases are used to identify and analyze hydroxyl/anion exchange by a comparable strategy. The model was able to produce data that agreed with experimental data in the literatur with an accuracy equal to experimental error. One program, called PROPIONATE, uses the weak acid, propionic acid, to identify cation channels such as the sodium-proton exchanger or the calcium-dependent, potassium channel. A second program, called BASE, is more general because either a weak acid such as propionic acid or a weak base such as ammonia may be used individually or together. When experimental data ara available, the programs may be used to calculate permeability coefficients for ion channels and the capacity of intracellular buffers. The programs may be used also in the design of experiments. Initial values may be assigned to intracellular and extracellular electrolyte and proton concentrations. Values for intracellular buffer capacity and channel permeabilities may be chosen. The program will then generate changes in ions, cell volume, and intracellular pH when either a weak acid, a weak base of combination of the two is added to the external medium.     

Cell size homeostasis is maintained by CDK4-dependent activation of p38 MAPK

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应用叶绿素荧光法测定微藻生物量的方法

为了探求叶绿素荧光值与海洋微藻生物量的关系,利用TD-700型叶绿素荧光仪测定了6种典型海洋赤潮藻在不同生长期(指数生长期和稳定生长期)时的叶绿素荧光值,同时用传统方法测定细胞密度,且利用Leica Qwin软件测量细胞大小。结果显示:微藻在同一生长时期细胞密度与叶绿素荧光值存在极显著的正相关关系,不同生长时期细胞密度也与单位叶绿素荧光值存在较显著正相关关系。因此,利用叶绿素荧光仪测定微藻生物量的方法是切实可行的,具有快捷方便、灵敏度高、可靠性强的优点。     

Genome size is a strong predictor of cell size and stomatal density in angiosperms

Across eukaryotes phenotypic correlations with genome size are thought to scale from genome size effects on cell size. However, for plants the genome/cell size link has only been thoroughly documented within ploidy series and small subsets of herbaceous species. Here, the first large-scale comparative analysis is made of the relationship between genome size and cell size across 101 species of angiosperms of varying growth forms. Guard cell length and epidermal cell area were used as two metrics of cell size and, in addition, stomatal density was measured. There was a significant positive relationship between genome size and both guard cell length and epidermal cell area and a negative relationship with stomatal density. Independent contrast analyses revealed that these traits are undergoing correlated evolution with genome size. However, the relationship was growth form dependent (nonsignificant results within trees/shrubs), although trees had the smallest genome/cell sizes and the highest stomatal density. These results confirm the generality of the genome size/cell size relationship. The results also suggest that changes in genome size, with concomitant influences on stomatal size and density, may influence physiology, and perhaps play an important genetic role in determining the ecological and life-history strategy of a species.     

Competition between Shoots in Stands of Clonal Plants

Abstract Data on shoot turnover, shoot size distributions and individual shoot growth in stands of clonal plants are reviewed and compared with shoot density regulation in non-clonal plants. Shoots are the smallest units capable of independent existence in clonal as well as unitary plants and this comparison allows an investigation of the impact of integration and other factors on clonal shoot dynamics. Physiological integration, the capacity of clonal plants to exchange resources and growth substances between interconnected shoots, has long been held responsible for the ability of clonal plants to prevent shoot overproduction and for the general lack of density-dependent mortality and self-thinning. A review of published data leads to the conclusion that the effects of integration on shoot dynamics in clonal plants have been overestimated. Other characteristics such as the density-dependent control of meristem activity, the synchronization of shoot growth in spring and the maximum shoot size, seem more important for the deviating behaviour of shoot populations of clonal plants.     

Genome size scaling through phenotype space

Background and Aims: Early observations that genome size was positively correlatedwith cell size formed the basis of hypothesized consequencesof genome size variation at higher phenotypic scales. This scalingwas supported by several studies showing a positive relationshipbetween genome size and seed mass, and various metrics of growthand leaf morphology. However, many of these studies were undertakenwith limited species sets, and often performed within a singlegenus. Here we seek to generalize the relationship between genomesize and the phenotype by examining eight phenotypic traitsusing large cross-species comparisons involving diverse assemblagesof angiosperm and gymnosperm species. These analyses are presentedin order of increasing scale (roughly equating to the numberof cells required to produce a particular phenotypic trait),following the order of: cell size (guard cell and epidermal),stomatal density, seed mass, leaf mass per unit area (LMA),wood density, photosynthetic rate and finally maximum plantheight. Scope: The results show that genome size is a strong predictor of phenotypictraits at the cellular level (guard cell length and epidermalcell area had significant positive relationships with genomesize). Stomatal density decreased with increasing genome size,but this did not lead to decreased photosynthetic rate. At higherphenotypic scales, the predictive power of genome size generallydiminishes (genome size had weak predictive power for both LMAand seed mass), except in the interesting case of maximum plantheight (tree species tend to have small genomes). There wasno relationship with wood density. The general observation thatspecies with larger genome size have larger seed mass was supported;however, species with small genome size can also have largeseed masses. All of these analyses involved robust comparativemethods that incorporate the phylogenetic relationships of species. Conclusions: Genome size correlations are quite strong at the cellular levelbut decrease in predictive power with increasing phenotypicscale. Our hope is that these results may lead to new mechanistichypotheses about why genome size scaling exists at the cellularlevel, and why nucleotypic consequences diminish at higher phenotypicscales.     

代谢工程与重组大肠杆菌的发酵

利用代谢工程可以在重组大肠杆菌的改良中减少代谢副产物乙酸的累积,优化代谢系统,利于重组蛋白质的高表达以及重组菌的高密度发酵。应用代谢工程改良重组大肠杆菌主要包括阻断乙酸产生的主要途径、限制糖酵解途径上的碳代谢流、将过量的丙酮酸转化为其它低毒的副产物以及对碳代谢流进行分流等几个方面的工作。     

氧化修饰LDL诱导U937细胞凋亡及其机制探讨

用氧化修饰低密度脂蛋白（ox-LDL）诱导人髓系白血病细胞株U937细胞凋亡,并研究其作用机制.用脱氧核苷酸转移酶介导的dUTP切口末端标记技术(TUNEL法)、流式细胞仪和DNA断裂分析检测细胞凋亡;用免疫组化检测c-fos、c-jun和c-myc蛋白表达,RT-PCR显示c-fos、c-jun和c-myc mRNA表达水平.结果表明ox-LDL可致U937细胞凋亡,其作用具有浓度效应;ox-LDL可以上调c-fos、c-jun和c-myc基因表达,使c-fos、c-jun和c-myc蛋白合成增多,最终诱导U937细胞凋亡.