林业入侵植物假苍耳对Cu^2＋的吸附性

选取林业入侵植物假苍耳（Iva xanthifolia）叶片匀浆体（LSI）和茎匀浆体（SSI）作为生物吸附材料,考察了溶液pH值、吸附时间、Cu^2＋浓度对吸附性能的影响,确定了最佳吸附pH值为6．0-7．0,吸附平衡时间为30分钟,处理水体中的Cu^2＋浓度应不超过800mg·L^-1。采用Langmuir和Freundlich等温吸附模型进行线性拟合,推算出LSI和SSI的饱和吸附率分别为28．68mg·g^-1和13．06mg·g^-1。通过对吸附Cu^2＋前后的LSI和SSI进行傅立叶红外光谱和X射线衍射分析可知,假苍耳参与Cu。’吸附的主要物质是纤维素类和糖类,并且可能是由它们具有的-OH、-CONH2及-C=O等官能团提供结合位点。研究结果显示假苍耳有可能成为一种具有开发潜力的新型重金属生物吸附材料。     

Microbial reduction of ethyl acetoacetate to ethyl (R)-3-hydroxybutyrate in an ionic liquid containing system

A hydrophilic ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF₄) was successfully employed as co-solvent for asymmetric bioreduction of ethyl acetoacetate (EOB) to ethyl (R)-3-hydroxybutyrate (R-EHB) catalyzed by Pichia membranaefaciens Hansen ZJPH07 cells. The results demonstrated that the addition of [BMIM]BF₄ in reaction system can markedly reduce the substrate inhibition and moderately improve the enantioselectivity compared to that in monophasic aqueous system. Among different alcohols and carbohydrates tried as co-substrate, glucose was a proper electron donor. Although isopropanol gave the best enantioselectivity with the highest yield, S-enantiomer was obtained. To optimize the bioreduction, some reaction parameters for the biosynthesis of R-EHB in this IL-containing system were investigated, such as temperature, buffer pH, shaking speed, substrate concentration, wet cells concentration and reaction time. Under the optimum conditions, best conversion of 77.8% and product enantiomeric excess (e.e.) of 73.0% were obtained. A comparative study was performed either in the presence or in the absence of [BMIM]BF₄, higher reaction yield (77.8% versus 68.5%) and product e.e. (73.0% versus 65.1%) were observed in IL-containing system with 0.55 M of the substrate, but 0.35 M of substrate concentration for the reduction in aqueous system without the addition of [BMIM]BF₄.     

表达O型口蹄疫病毒VPl基因的重组病毒BHV-1的构建与鉴定

[目的]为了构建表达口蹄疫病毒(O/china/99)VP1基因的牛疱疹病毒1型,将人工合成的口蹄疫病毒VP1基因插入到巨细胞病毒(CMV)启动子之下构建gE基因缺失转移载体.[方法]利用磷酸钙介导转染法将该转移载体与亲本病毒BHV-1/gE-/LacZ+的基因组DNA共转染牛鼻甲细胞后收获增殖的病毒.通过筛选白色病毒蚀斑,得到重组病毒BHV-1/gE-/VP1.[结果]PCR检测结果表明VP1基因已经插入到了重组病毒BHV-1/gE-的基因组中,间接免疫荧光试验和Westem blot证实了BHV-1/gE-/VP1中的VP1基因在感染的细胞中获得了表达.[结论]本研究成功地构建了表达口蹄疫病毒VP1基因的重组病毒BHV-1/gE-/VP1,为研制口蹄疫及其他重要牛传染病的BHV-1病毒载体疫苗奠定了基础.     

Plant biodiversity in a larch plantation from the view point of photosynthetic nitrogen use efficiency in northeast China

Forest floor of larch species often provides growth habitat for many kinds of understory species because of relatively sparse structure in a larch canopy. A rich flora of forest understory species may play an essential role in maintaining fertility of a larch stand. An attempt was made to evaluate photosynthetic nitrogen use efficiency (PNUE) of many understory and overstory species according to their Raunkiaer lifeform. By studying 72 perennial deciduous species in a larch plantation in northeast China, marked photosynthetic differences between phanerophytes (Ph) and other three lifeforms of chamaephytes (Ch), hemicryptophytes (He), and cryptophytes (Cr) were found, with marginal differences found among Ch, He, and Cr. Ph species had much lower PNUE, and much lower values of rate of nitrogen allocation to chlorophyll (Chl./N) and nitrogen allocation to carboxylation processes (V _cmax/N) were concurrently observed in Ph compared with the other three lifeforms. Ph had much lower leaf nitrogen per unit of projection area (N _area) and specific leaf area (SLA, cm² g^–1). At lower SLA, for Ph species the change of PNUE with SLA was small, but these changes became very large at higher SLA for Ch, He, and Cr species. Our findings indicate that leaf morphological change is important for clarifying photosynthesis differences among species with different lifeform.     

假苍耳的生活史进程中几种生理生化指标的变化

本文试图从生理生化的角度对假苍耳(Iva xanthifolia)生活史进程中可溶性糖类、赤霉素、单宁以及黄酮的变化进行探讨。通过对假苍耳在生长发育期间几种生理生化指标的测定,结果表明,在假苍耳生活史进程的不同阶段,其体内各种代谢产物的含量基本都在种子或芽阶段具有最高含量。此外,不同发育阶段可溶性还原糖含量的变化规律相似：芽＞花序＞苗＞成株＞种子。除在花序和苗阶段没有测到海藻糖,其他各阶段海藻糖的含量变化如下：芽＞成株＞种子。另外,只有在种子阶段检测到棉子糖,其含量为15.43 mg·g~(-1)。赤霉素含量的变化规律如下：种子＞芽≈苗≈花序＞成株。单宁含量的变化趋势：种子＞成株＞苗＞芽＞花序。黄酮含量的变化趋势：种子＞芽＞成株≈花序＞苗。值得注意的是,当单宁/黄酮的比值接近1时,植物体内需要的单宁和黄酮的含量则相对较低;相反,当单宁/黄酮的比值接近0时,植物体内需要的单宁和黄酮的含量则较高。     

A series of iridium complexes equipped with inert shields: Highly efficient bluish green emitters with reduced self-quenching effect in solid state

In this paper, we synthesize a series of cyclometalated ligands and their corresponding Ir(III) complexes using pentane-2,4-dione as the auxiliary ligand. We discuss the photophysical properties of these Ir(III) complexes in detail, including their UV-Vis absorption spectra, photoluminescence spectra in solid and liquid states, luminescence decay lifetimes, and luminescence quantum yields. The correlation between self-quenching effect and molecular structure is also investigated. It is found that these Ir(III) complexes are solid-emitting ones due to their reduced self-quenching in solid state. Theoretical calculation and experimental data reveal that the following two reasons should be responsible for the reduced self-quenching in solid state: (1) pentane-2,4-dione, phenyl, and triphenylamine moieties serve as inert shields for the excited state Ir(III) complexes; (2) the radiative decay process in these Ir(III) complexes is accelerated by the introduction of electron-donors, and thus partly immune from self-quenching caused by intermolecular action.     

Addition of HPMA affects seed germination, plant growth and properties of heavy saline-alkali soil in northeastern China: comparison with other agents and determination of the mechanism

China has a large area of inland saline-alkali land, equivalent to 40% of the total cultivated land in the country. The principal features of these lands are high salt content, high pH, and poor soil structure with low water infiltration and poor drainage. These conditions effectively prevent the exploitation of such land for agriculture. In this study, we have compared 17 soil conditioning agents for their abilities to promote seed germination and growth under both laboratory and field conditions. One of these, Hydrolyzed Polymaleic Anhydride (HPMA), was identified as a highly effective agent for soil improvement. Laboratory germination experiments and laboratory and field cultivation of a variety of plants both showed that addition of HPMA could significantly increase the germination percentage and plant growth rate. Distinct from other Ca-carrier agents such as gypsum, HPMA increases the dissolution of CaCO₃, which is abundant in the calcareous saline-alkali soils. This allows Ca²⁺ in soil solution to displace the over-abundant Na⁺ in the soil colloids. This process greatly improves soil properties such as the bulk density, which decreased, and the capillary soil rise height of water and soil water infiltration rate, which increased. Direct SEM and AFM imagery showed flocculent soil precipitation (soil aggregates) after HPMA addition, and a looser structure of those aggregates. The addition of HPMA also reduced the soil pH and EC. These changes in soil chemical and physical properties are a likely explanation for the soil improvement effected by HPMA. The high content of insoluble CaCO₃ in saline-alkali land such as that in northeastern China (up to 13%) favors the further exploration of HPMA as an ameliorative agent.     

Next-generation sequencing of the Chinese hamster ovary microRNA transcriptome: Identification, annotation and profiling of microRNAs as targets for cellular engineering

Chinese hamster ovary (CHO) cells are the predominant cell factory for the production of recombinant therapeutic proteins. Nevertheless, the lack in publicly available sequence information is severely limiting advances in CHO cell biology, including the exploration of microRNAs (miRNA) as tools for CHO cell characterization and engineering. In an effort to identify and annotate both conserved and novel CHO miRNAs in the absence of a Chinese hamster genome, we deep-sequenced small RNA fractions of 6 biotechnologically relevant cell lines and mapped the resulting reads to an artificial reference sequence consisting of all known miRNA hairpins. Read alignment patterns and read count ratios of 5' and 3' mature miRNAs were obtained and used for an independent classification into miR/miR* and 5p/3p miRNA pairs and discrimination of miRNAs from other non-coding RNAs, resulting in the annotation of 387 mature CHO miRNAs. The quantitative content of next-generation sequencing data was analyzed and confirmed using qPCR, to find that miRNAs are markers of cell status. Finally, cDNA sequencing of 26 validated targets of miR-17-92 suggests conserved functions for miRNAs in CHO cells, which together with the now publicly available sequence information sets the stage for developing novel RNAi tools for CHO cell engineering.     

Adaptive evolution of foraging-related traits in a predator-prey community

In this paper, with the method of adaptive dynamics and geometric technique, we investigate the adaptive evolution of foraging-related phenotypic traits in a predator-prey community with trade-off structure. Specialization on one prey type is assumed to go at the expense of specialization on another. First, we identify the ecological and evolutionary conditions that allow for evolutionary branching in predator phenotype. Generally, if there is a small switching cost near the singular strategy, then this singular strategy is an evolutionary branching point, in which predator population will change from monomorphism to dimorphism. Second, we find that if the trade-off curve is globally convex, predator population eventually branches into two extreme specialists, each completely specializing on a particular prey species. However, if the trade-off curve is concave-convex-concave, after branching in predator phenotype, the two predator species will evolve to an evolutionarily stable dimorphism at which they can continue to coexist. The analysis reveals that an attractive dimorphism will always be evolutionarily stable and that no further branching is possible under this model.