木本植物水力学结构之导管长度研究进展

导管作为多数被子植物木质部水分运输的主要通道, 了解其结构及功能对研究被子植物水力学特性及植物对环境的适应性有着重要的作用。导管长度作为导管解剖特征之一, 对水分运输的安全性及有效性有着重要的影响。该文概述了导管长度测量及计算的方法, 导管长度在种内及种间的分布, 导管长度与导管直径的关系, 导管长度与导水率的关系及导管长度对建立栓塞脆弱曲线的影响, 并对未来导管长度的研究工作重点提出了建议: 1)改进灌注物质, 使灌注更加充分且更利于观察、提高计算精度、发展活体动态测量技术; 2)建立导管在植物不同器官及整体的分布网络以及不同生活型、不同地区的导管长度数据库; 3)对导管直径在导管方向的变化, 导管长度与其他导管特性之间的关系进行研究; 4)光学测量建立栓塞脆弱曲线技术的兴起, 可为解决离心机法建立栓塞脆弱曲线的真实与准确与否的争议提供新的方向。更深入地了解导管长度在植物水力功能中担负的角色, 可以为耐旱、抗旱品种选育提供理论基础。     

Post-Golgi protein traffic in the plant secretory pathway

The Golgi apparatus in plants is organized as a multitude of individual stacks that are motile in the cytoplasm and in close association with the endoplasmic reticulum (ER) (Boevink et al. in Plant J 15:441–447, 1998). These stacks operate as a sorting centre for cargo molecules, providing modification and redirection to other organelles as appropriate. In the post-Golgi direction, these include vacuole and plasma membrane, and specialized transport routes to each are required to prevent mislocalization. Recent evidence in plant cells points to the existence of post-Golgi organelles that function as intermediate stations for efficient protein traffic, as well as to the influence of small GTPases such as Rabs and ARFs on post-Golgi trafficking. This review focuses on the latest findings on post-Golgi trafficking routes and on the involvement of GTPases and their effectors on the trafficking of proteins in the plant secretory pathway. Sally L. Hanton and Loren A. Matheson have contributed equally to this work.     

Addiction,Heroin‐Assisted Treatment and the Idea of Abstinence: A reply to Henden

In our previous article on the question whether heroin addicts are able to give informed consent voluntarily to research on heroin‐assisted treatment, we criticized the ongoing bioethical discussion of a flawed conceptualization of heroin addicts' options. As a participant in this discussion, Edmund Henden defends the conceptualization as sufficient for determining whether heroin addicts are able to give informed consent to the research on heroin‐assisted treatment voluntarily. This discussion on research on heroin‐assisted treatment seems to go astray in several respects. In his reply to our article Henden maintains some of the biases, such as the necessity of abstinence in recovery, that seem to prevail in addiction research on a more general level as well. These biases run the danger of having implausible ethical implications on stakeholders in addiction research and treatment. In our reply to him, we will further clarify and discuss the importance of describing the relevant issues in plausible terms that do justice to the realities of the cases of informed consent in research on heroin‐assisted treatment and also raise a wider issue of the ethics of wording as well as of the narrow scope, or ‘tunnel vision’, in addiction research as currently conducted.     

RESEARCH ON INSECTICIDES FROM PLANTS IN CHINA

Abstract  An overview is presented on recent (1989–19911 investigations on insecticidal plants in China, specially in South China. The main emphasis was laid on studies of Meliaceae including Azadirachta indica, Melia azedarach and M. toosendan , as well as on Rhododendron molle, Derris elliptica, Tephrosia voglii, Ajuga nipponensis, Plumbago idea and Celastrus anplatus . Research work on the bioactivities and application of essential oils from plants for the control of stored-grain insects is also discussed. The results of these investigations reveal a great potential of the active ingredients of a number of Chinese plants for integrated pest management, as well as for using these natural product models as guides for the synthesis of a novel class of insecticides.     

Integrating hormones into the floral-transition pathway of Arabidopsis thaliana

The transition from vegetative to reproductive growth is a major phase change in angiosperms. In annual plants such as Arabidopsis thaliana (Arabidopsis), this change is irreversible, and as such, the regulation of its timing must be tightly controlled. Plant hormone (phytohormone) signalling is known to regulate suites of morphogenic processes in Arabidopsis a role in flowering-time control is starting to emerge as one key-controlling step. This review focuses on experimental evidence in the Arabidopsis that both classical and newly described phytohormones serve within the signal network leading to a reproductive phase transition, as both positive and repressive elements, depending on the phytohormone and growth conditions. Examples of genetic and pharmacological experiments that implicate phytohormones as components of the floral-timing syndrome will be described. I hope that this review will serve as a primer for future research on the mechanisms of action for each respective phytohormone on the floral transition in Arabidopsis, and lead to further experimentation on the crosstalk that likely bridges between them.     

灵长类卵母细胞体外发育潜能的调控

灵长类卵母细胞细胞质成熟调控研究较为滞后,使得体外成熟的灵长类卵母细胞的胚胎发育潜能十发低下。提高其潜能对治疗人类不育症有重要的应用价值,并可推动灵长类胚胎发育的研究。基于猕猴卵母细胞质成熟调控研究,讨论了无血清成熟培养基中雌激素和孕激素、能量物质、氨基酸对卵母细胞质成熟的影响,以及动物年龄和生殖周期与发育潜能的关系。从分子水平进一步解释这些因素的作用,阐明卵母细胞质成熟的机理将是今后工作的方向。     

The effect of acetate on population heterogeneity in different cellular characteristics of Escherichia coli in aerobic batch cultures

Acetate as the major by-product in industrial-scale bioprocesses with Escherichia coli is found to decrease process efficiency as well as to be toxic to cells, which has several effects like a significant induction of cellular stress responses. However, the underlying phenomena are poorly explored. Therefore, we studied time-resolved population heterogeneity of the E. coli growth reporter strain MG1655/pGS20PrrnBGFPAAV expressing destabilized green fluorescent protein during batch growth on acetate and glucose as sole carbon sources. Additionally, we applied five fluorescent stains targeting different cellular properties (viability as well as metabolic and respiratory activity). Quantitative analysis of flow cytometry data verified that bacterial populations in the bioreactor are more heterogeneous in growth as well as stronger metabolically challenged during growth on acetate as sole carbon source, compared to growth on glucose or acetate after diauxic shift. Interestingly, with acetate as sole carbon source, significant subpopulations were found with some cells that seem to be more robust than the rest of the population. In conclusion, following batch cultures population heterogeneity was evident in all measured parameters. Our approach enabled a deeper study of heterogeneity during growth on the favored substrate glucose as well as on the toxic by-product acetate. Using a combination of activity fluorescent dyes proved to be an accurate and fast alternative as well as a supplement to the use of a reporter strain. However, the choice of combination of stains should be well considered depending on which population traits to aim for.     

重组质粒在减毒沙门氏菌中的稳定性及其对细菌侵袭力的影响

将含有外源基因的重组真核表达质粒pcDNA3-F和pCI-F转化减毒鼠伤寒门氏菌,探讨质粒类型和插入片段对重组质粒在细菌内的稳定性和细菌侵袭力的影响。结果表明,外源质粒可降低减毒沙门氏菌在体外的增殖能力和侵袭力,也影响细菌在鸡体内的存活力;就质粒类型而言,pCI的影响大于pcDNA3,而以携带外源基因的重组质粒影响较为显著;外源基因插入也影响质粒在宿主菌内的稳定性。提示利用减毒鼠伤寒沙门氏菌为载体传递DNA疫苗研究时,要考虑质粒类型与其在宿主菌内稳定性的关系、携带外源基因重组质粒对载体菌侵袭力和存活力的影响等问题。     

Impact Assessment of Biodiversity and Carbon Pools from Land Use and Land Use Changes in Life Cycle Assessment,Exemplified with Forestry Operations in Norway

There is a strong need for methods within life cycle assessment (LCA) that enable the inclusion of all complex aspects related to land use and land use change (LULUC). This article presents a case study of the use of one hectare (ha) of forest managed for the production of wood for bioenergy production. Both permanent and temporary changes in above‐ground biomass are assessed together with the impact on biodiversity caused by LULUC as a result of forestry activities. The impact is measured as a product of time and area requirements, as well as by changes in carbon pools and impacts on biodiversity as a consequence of different management options. To elaborate the usefulness of the method as well as its dependency on assumptions, a range of scenarios are introduced in the study. The results show that the impact on climate change from LULUC dominates the results, compared to the impact from forestry operations. This clearly demonstrates the need to include LULUC in an LCA of forestry products. For impacts both on climate change and biodiversity, the results show large variability based on what assumptions are made; and impacts can be either positive or negative. Consequently, a mere measure of land used does not provide any meaning in LCA, as it is not possible to know whether this contributes a positive or negative impact.     

Control of benzylamine oxidase activity in Kluyveromyces fragilis grown on primary amines as nitrogen source

Abstract After growth on a mixture of ammonium and either methylamine or n -butylamine as nitrogen sources, benzylamine oxidase activity in yeasts from a number of different genera was found to be repressed to a lesser extent by ammonium than was methylamine oxidase. Catalase activity was better repressed by ammonium with methylamine as the nitrogen source than with n -butylamine. During growth of Kluyveromyces fragilis on equimolar mixtures of ammonium and an amine as nitrogen sources, benzylamine oxidase synthesis began during the period of exclusive growth on ammonium, and a period of simultaneous use of both nitrogen sources was observed just before the ammonium was exhausted. Addition of ammonium to cultures growing on n -butylamine as nitrogen source had no immediate repressive effect on benzylamine oxidase or catalase synthesis. However, growth on limiting ammonium in the absence of amines did give rise to low levels of amine oxidase and derepression of catalase activity. It is concluded that benzylamine oxidase in yeasts is induced strongly by amines as well as being less strongly repressed by ammonium than methylamine oxidase.     

Therapy-induced plasticity of cognitive functions in MS patients: Insights from fMRI

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system whose pathological mechanisms are still not completely understood. Physical as well as cognitive deterioration are consequences within the disease process that have an extensive impact on the patient's quality of life. Therefore, understanding the functional background of spontaneous as well as induced remission is of high relevance. Studies on visualization of therapeutic effects of pharmacological or cognitive treatment by functional magnetic resonance imaging (fMRI) are still rare. From fMRI studies on focal brain lesions hypotheses on mechanisms of brain reorganization can be derived. This contribution will first give an overview of the existing studies using fMRI in MS, on cognitive decline, on cognitive treatment studies and its therapeutic effects on behavioural readouts in MS, and on therapy-induced brain plasticity and its possible visualization by fMRI. Results of a study on correlating the effects of cognitive training with changes in brain organization in patients with mild to severe cognitive impairment will be reported.     

中国植物质杀虫剂的研究(英语)

本文主要集中反映及讨论中国植物质杀虫剂近年主要的研究成果.内容包括:印楝、苦楝、川楝、黄杜鹃、毛鱼藤、非州山毛豆、紫背金盘及其它杀虫植物.还讨论了植物质杀虫剂的活性及在害虫防治上的应用.     

Communication of cyanobacteria with plant partners during association formation

Data are presented on the physiological diagnostics of cyanobacterial communication with higher plants in natural symbioses (plant syncyanoses) and in model associations, as well as on the interaction of the partners without spatial integration. Emphasis is placed on changes in cyanobacterial features important for symbiogenesis. The multicomponent composition and the possible nature of the factors that enable partner communications are discussed with hormogonia formation and taxis as an example.     

Aphidophagous insect communities in tree crowns of the neophyte Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] and Norway spruce (Picea abies L.)

Abstract:  Number of specimens and species as well as structure of aphidophagous communities in tree crowns of Douglas-fir ( Pseudotsuga menziesii ) and Norway spruce ( Picea abies ) were studied in different forest stand types (Douglas-fir-, spruce- and beech-dominated) in southern Germany in the year 2000, using flight-interception traps. Total as well as average numbers of specimens and species of aphid predators were higher on Douglas-fir in all stand types. This was particularly evident in Douglas-fir-dominated stand type. The aphidophagous community revealed a low β -diversity on spruce but a high β -diversity on Douglas-fir between stand types. Both species, with a broad and narrow ecological niche, respectively, were responsible for a community on Douglas-fir conspicuous different from that on spruce.     

Progress and prospects in the use of peroxidase to study cell development

The need for peroxidase purification is stressed as a requirement for comparative studies on isoenzyme structure as well as for detailed investigations on biosynthesis. A single cationic protein possessing the major peroxidase activity was isolated from the medium in which peanut cells had grown. The antibodies raised against this pure protein were employed as a probe to study the site of synthesis of peroxidase in the cell as well as the proportion of total synthesized protein which was peroxidase. Structural studies on the purified isoenzymes suggest the presence of three gene loci for peroxidase in cultured peanut cells. The results are discussed together with potential assays for induction of this enzyme and the relationship to cell development.     

Biotechnological studies in the Far-Eastern Region of Russia

Achievements and problems in both the studies on natural bioactive compounds from the Far-Eastern higher plants and marine invertebrates and development of the corresponding biotechnologies concerning new drugs and food supplements, as well as pharmaceutical leads are discussed. Special emphasis is made on recent results from the Far-eastern Institutions belonging to the Russian Academy of Sciences, and their application in both medicine and the food industry, as well as on peculiarities of biological and chemical diversity in the North-Western part of Asia and adjoining seas.     

Lead (Pb) is Now a Non-Threshold Substance: How Does this Affect Soil Quality Guidelines?

Risk-based concentrations (RBCs) for lead (Pb) in soil were estimated using equations for development of Canadian soil quality guidelines. Based on the latest toxicological assessments by various health agencies, risk specific doses for Pb were defined for children (for impacts on intelligence quotient [IQ]) and adults (for impacts on systolic blood pressure [SBP] as well as protection of fetal effects in the case of pregnant women). The analysis suggests that a RBC in soil of 180 μg/g (dry weight) for residential and other areas where children routinely play is protective of a 1 IQ point decrement on a population basis and may actually be associated with decrements of less than 0.2 to 0.35 IQ points when the weight of evidence is considered. For soils that children do not contact on a frequent basis, RBCs as great as 8800 μg/g are considered to be protective of a 1 mmHg SBP increase in adults (as well as IQ effects to the fetus). It is stressed that non-soil sources of Pb may be even more important than soil. The approach may also be useful in jurisdictions outside of Canada as the importance of considering IQ decrements on a population basis rather than an individual basis and uncertainties in soil ingestion rates are considered.     

四川缙云山森林群落林窗边缘效应的研究

 本文运用Shannon—Wiener物种多样性指数、Simpson生态优势度指标以及边缘效应强度指数,对缙云山亚热带森林群落林窗的边缘效应现象进行了初步研究。29个林窗样地不同部位上述指标的测定表明用物种多样性指数拟合边缘效应测度通式,缙云山亚热带森林群落林窗的边缘效应强度值为1—3左右;而用生态优势度值拟合边缘效应强度测式,则上述边缘效应强度值为0.1一1.2左右。研究表明林窗边缘区由于边缘效应的作用有增大物种多样性的趋势。而林窗面积、所处坡向以及林窗所在的森林群落类型,都对处于不同发育阶段的林窗的边缘效应强度具有影响。在此基础上,本文对林窗边缘效应强度的变化规律、效应性质、测定意义以及对森林营造和优化管理上的作用进行了一定探讨。     

Role of 4-aminobutyrate aminotransferase in the arginine metabolism of Pseudomonas aeruginosa.

4-Aminobutyrate aminotransferase (GABAT) from Pseudomonas aeruginosa was purified 64-fold to apparent electrophoretic homogeneity from cells grown with 4-aminobutyrate as the only source of carbon and nitrogen. Purified GABAT catalyzed the transamination of 4-aminobutyrate, N2-acetyl-L-ornithine, L-ornithine, putrescine, L-lysine, and cadaverine with 2-oxoglutarate (listed in order of decreasing activity). The enzyme is induced in cells grown on 4-guanidinobutyrate, 4-aminobutyrate, or putrescine as the only carbon and nitrogen source. Cells grown on arginine or on glutamate contained low levels of the enzyme. The regulation of the synthesis of GABAT as well as the properties of the mutant with an inactive N2-acetyl-L-ornithin 5-aminotransferase suggest that GABAT functions in the biosynthesis of arginine by convertine N2-acetyl-L-glutamate 5-semialdehyde to N2-acetyl-Lornithine as well as in catabolic reactions during growth on putrescine or 4-guanidinobutyrate but not during growth on arginine.