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.     

紫外辐射增强对植物糖代谢的影响

综述了UV-B辐射增强对植物叶片、茎、根、果实以及籽粒中糖含量影响的研究现状与动态,从生理学角度分析了UV-B辐射对植物糖含量和糖代谢相关的一些重要反应及其影响植物糖含量和糖代谢的关键酶的响应,并从植物的光合碳固定、糖的合成与分解等方面阐述了UV-B影响糖含量及糖代谢的可能机理。展望了今后紫外辐射增强对植物糖代谢影响的研究重点和研究方向。     

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。     

Molecular characterization of avian-like H1N1 swine influenza a viruses isolated in Eastern China, 2011

Currently, three predominant subtypes of influenza virus are prevalent in pig populations worldwide: H1N1, H3N2, and H1N2. European avian-like H1N1 viruses, which were initially detected in European pig populations in 1979, have been circulating in pigs in eastern China since 2007. In this study, six influenza A viruses were isolated from 60 swine lung samples collected from January to April 2011 in eastern China. Based on whole genome sequencing, molecular characteristics of two isolates were determined. Phylogenetic analysis showed the eight genes of the two isolates were closely related to those of the avian-like H1N1 viruses circulating in pig populations, especially similar to those found in China. Four potential glycosylation sites were observed at positions 13, 26, 198, 277 in the HA1 proteins of the two isolates. Due to the presence of a stop codon at codon 12, the isolates contained truncated PB1-F2 proteins. In this study, the isolates contained 591Q, 627E and 701N in the polymerase subunit PB2, which had been shown to be determinants of virulence and host adaptation. The isolates also had a D rather than E at position 92 of the NS1, a marker of mammalian adaptation. Both isolates contained the GPKV motif at the PDZ ligand domain of the 3′ end of the NS1, a characteristic marker of the European avian-like swine viruses since about 1999, which is distinct from those of avian, human and classical swine viruses. The M2 proteins of the isolates have the mutation (S31N), a characteristic marker of the European avian-like swine viruses since about 1987, which may confer resistance to amantadine and rimantadine antivirals. Our findings further emphasize the importance of surveillance on the genetic diversity of influenza A viruses in pigs, and raise more concerns about the occurrence of cross-species transmission events.     

药用植物生长发育与有效成分积累关系研究进展

药用植物有效成分是其发挥临床疗效的物质基础, 也是评价药材质量的重要指标, 而这些有效成分的产生和分布通常有种属、器官、组织以及生长发育时期的特异性。明确药用植物主要药用成分在植物不同生长发育阶段的积累变化规律和形成机制, 对中药品质与临床疗效有重要的指导意义。该文主要概述了不同发育阶段对药用植物不同药用部位(根、茎、叶、花、果实和种子)中有效成分积累的影响, 并对药用植物次生代谢产物合成和积累机制的相关研究技术进行了展望, 为生产实践上调控药用植物次生物质合成、药用植物的合理利用以及提高中药材品质奠定了理论基础。     

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.