晋陕宁黄土丘陵区生态修复与农林牧业持续发展仿真研究

晋陕宁黄土丘陵区土壤侵蚀严重,生态环境脆弱,不合理利用土地是其主要原因,生态修复与环境重建是该区生态与经济持续发展的重要战略措施。应用系统动力学（System Dynamic,简称SD）和“反馈控制（Feedback control）理论建立了该区生态修复和环境重建的SD模型,它分为人口、农业、林业、牧业、农村经济、土壤侵蚀和生态环境6个模块,仿真时间1990～2080年,步长1a。经检验该SD模型的有效性为93．5％,可用于未来仿真预测。根据该区的生态环境特点和农牧业发展现状,选择生态环境恢复重建的3种典型模式——同步发展模式（A模式）、逐步调整模式（B模式）和现状发展模式（C模式）进行仿真研究,预测3种模式2000～2080年的土壤侵蚀、土地利用的发展动态以及农林牧业和生态环境演化趋势。仿真结果表明：土地利用与农、林、牧业持续发展密切相关,坡耕地和草场退化是制约农林牧业发展的主要因素。合理调整土地利用结构和加速治理侵蚀,可促进生态环境逐步恢复和农林牧业持续发展。同步发展模式（A模式）是该区生态修复和环境重建的3个仿真模式中的最优策略,它可促进农林牧协调发展和生态一经济趋向良性循环,并提出该区生态修复与环境重建的对策措施。该SD模型结构合理,运行功能良好,能较真实的模拟具有多变量、非线性变量的复杂生态系统的动态行为,为生态修复研究提供一种有效工具。     

大气CO2浓度增加对昆虫的影响

大气CO2浓度增加已经受到国内外的极大关注.CO2浓度升高不但影响植物的生长发育,而且还改变植物体内的化学成分的组成与含量,从而间接地影响到植食性昆虫,并进而通过食物链影响到以之为食的天敌.根据国内外研究进展,结合多年的研究,系统介绍了CO2浓度变化对植物-昆虫系统影响的研究方法,论述了CO2浓度变化对植食性昆虫、天敌的作用规律及作用机理,探讨了CO2浓度变化对植物-植食性昆虫系统影响的特征,分析了未来研究发展的趋势及其存在的问题.     

Release of arachidonic acid by NMDA-receptor activation in the rat hippocampus

In hippocampal slices arachidonic acid released after NMDA post-synaptic receptor activation is thought to act as a retrograde trans-synaptic messenger which facilitates the pre-synaptic release of L-glutamate to be involved in the expression of long-term synaptic potentiation (LTP). We measured the mass amount of arachidonic acid released from hippocampal slices incubated under conditions which maintain the electrophysiological responsiveness of the slice. Melittin released arachidonic, oleic and docosahexaenoic acids by phospholipase A₂ activation but not palmitic or stearic acids. Of greater interestl-glutamate, N-methyl-d-aspartate and incubation conditions known to induce LTP selectively and rapidly increased the release of archidonic acid in amounts over basal levels of 200–300 ng/mg protein. This is the first direct determination of the mass amount of arachidonic acid released following NMDA receptor activation in the hippocampus.Special issue dedicated to Dr. Louis Sokoloff.     

主要农作物转基因研究现状和展望

近15年来,大豆、水稻、玉米、小麦等主要农作物转基因研究取得了较大进展,几乎各种遗传转化方法在这些作物上都取得了成功,尤其是农杆菌介导法,不仅在难转化的双子叶作物大豆上取得了成功,而且在单子叶作物水稻、玉米、小麦上先后取得了突破。同时,将一些与重要性状改良有关的外源基因转入了主要农作物,包括抗虫、抗病、抗除草剂、抗逆、品质改良、发育调控、营养吸收等。转基因大豆、玉米、棉花、油菜在生产上得到了大面积种植,产生了极大的经济效益,2004年全球转基因作物的种植面积达到了8100万公顷。本文对大豆、玉米、水稻和小麦等主要农作物转基因研究历史和产业化现状进行了综述,并对主要农作物转基因研究中存在的问题进行了分析。     

中国野鸦椿属植物化学成分及药理活性研究进展

野鸦椿属植物归属于省沽油科,主要分布于东亚以及东南亚,我国分布有两个种。该属植物化学成分结构丰富,包括酯类、三萜类、黄酮类等,药理活性广泛,如抗炎、抗肝纤维化、抗氧化等。本文从化学成分及药理活性方面对野鸦椿属植物的研究进行综述,以期为该属植物的深入研究与开发提供文献参考。     

大规模蛋白质相互作用组实验技术及其应用

大规模蛋白质相互作用研究的主要实验技术包括酵母双杂交技术、串联亲和纯化技术和蛋白质芯片技术,随着这些技术的不断发展和完善,科学家们在模式生物、哺乳动物、病原微生物中展开了大规模的蛋白质相互作用组研究,并进行了药物研发方面的研究,绘制了多种生物的蛋白质相互作用连锁图,揭示了多种蛋白质的新功能,为全面研究蛋白质（群）的分子作用机制、药物研发和疾病的临床预防与治疗等提供了崭新的线索。     

Theories for ecological restoration in changing environment: Toward ‘futuristic’ restoration

Ecological restoration is one of the fastest growing fields in applied ecology providing new ideas and opportunities for biological conservation and natural resource management. Despite countless attempts in the past, large portions of restoration projects have been considered unsuccessful mainly due to: unrealistic goals; inadequate restoration plans based on an ad-hoc approach; lack of explicit and quantified evaluation criteria for restoration success; lack of ecological understanding; social, economic, and political constraints; or combinations of these factors. Existing ecological theories, particularly succession theories, may provide a conceptual framework for a restoration trajectory. However, projecting a desirable trajectory and outcome is often challenged by the unpredictability of ecological communities in the changing environment. Particularly, the sustainability of reconstructed historic ecosystems appears to be an unlikely goal in the ever-changing and unpredictable future environment. This paper calls for a shift in the restoration paradigm from historic to futuristic. A futuristic restoration is: (i) to set realistic and dynamic (instead of static) goals for future, instead of past, environment; (ii) to assume multiple trajectories acknowledging the unpredictable nature of ecological communities and ecosystems; (iii) to take an ecosystem or landscape approach, instead of ad-hoc gardening, for both function and structure; (iv) to evaluate the restoration progress with explicit criteria, based on quantitative inference; and (v) to maintain long-term monitoring of restoration outcomes. A theoretical framework for futuristic restoration, in terms of goals, trajectories, evaluation criteria, and monitoring, along with a historical perspective is presented in this paper.     

Synaptic transmission and plasticity in the amygdala

Numerous studies in both rats and humans indicate the importance of the amygdala in the acquisition and expression of learned fear. The identification of the amygdala as an essential neural substrate for fear conditioning has permitted neurophysiological examinations of synaptic processes in the amygdala that may mediate fear conditioning. One candidate cellular mechanism for fear conditioning is long-term potentiation (LTP), an enduring increase in synaptic transmission induced by high-frequency stimulation of excitatory afferents. At present, the mechanisms underlying the induction and expression of amygdaloid LTP are only beginning to be understood, and probably involve both theN-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) subclasses of glutamate receptors. This article will examine recent studies of synaptic transmission and plasticity in the amygdala in an effort to understand the relationships of these processes to aversive learning and memory.     

养分管理对农田土壤微生物量的影响

土壤微生物与土壤质量、健康、植物的生产力和农业的可持续发展密切相关。任何对土壤中微生物的扰动都可能影响土壤的长期生产力,并可能产生严重后果。大量研究结果表明,肥料类型、施肥处理年限长短、施肥水平高低及施肥措施都会造成土壤成分的变化,进而影响土壤中微生物的生长以及繁殖。简要介绍了微生物量的几种测定方法,综述了各种养分管理措施对农田生态系统中土壤微生物量的影响,从而了解土壤微生物因人类对土壤的利用而发生的变化,以期为农业的可持续发展和生态环境的保护提供理论依据。     

实蝇共生菌研究进展

实蝇类昆虫(双翅目Diptera:实蝇科Tephritidae)是重要的农业害虫,为害农作物茎秆和水果,严重影响农业生产和果蔬贸易,被许多国家列为重要的检疫性有害生物。实蝇共生菌对宿主实蝇的取食、生殖、发育及环境适应能力具有重要作用。目前,已有21个属的共生细菌(Enterobacter、Klebsiella、Citrobacter、Pseudomonas、Providencia、Erwinia、Acetobacter、Serratia、Proteus、Hafnia、Cedecea、Arthrobacter、Lactobacillus、Micrococcus、Streptococcus、Staphylococcus、Vibrio、Hafnia、Deinococcacea、Bacillus、Wolba-chia)以及1个属的共生真菌(Candida)被鉴定。其中,肺炎杆菌Klebsiella pneumoniae、产酸克雷伯氏菌Klebsiella oxytoca、成团泛菌Pantoea agglomerans、费氏柠檬酸杆菌Citrobter freundii、阴沟肠杆菌Enterobacter cloaca...