足迹家族研究综述

综合测度人类社会的可持续发展状态是生态经济学者追求的重要目标。足迹家族由生态足迹、碳足迹和水足迹等一系列足迹类指标整合而成,旨在为决策者系统评估与权衡人类活动的环境影响提供理论和技术支持。从理论探索、整合实践和分类比较等三方面对足迹家族的研究现状进行了综述;在此基础上围绕极具争议的足迹定义、计算方法和加权方式等问题,深入分析了阻碍当前研究进一步推进的关键性因素;指出未来应从建立足迹类型学、完善跨区域投入产出模型、细化产品和机构环境足迹标准等方面入手,推动实现足迹家族的量化整合;并首次提出了足迹家族与行星边界耦合的构想,以期为监测和预警人类活动的生态阈值、促进环境影响评价向可持续性评价转变提供科学依据。     

Trait-based approaches to predicting biological control success: challenges and prospects

Identifying traits that are associated with success of introduced natural enemies in establishing and controlling pest insects has occupied researchers and biological control practitioners for decades. Unfortunately, consistent general relationships have been difficult to detect, preventing a priori ranking of candidate biological control agents based on their traits. We summarise previous efforts and propose a series of potential explanations for the lack of clear patterns. We argue that the quality of current datasets is insufficient to detect complex trait–efficacy relationships and suggest several measures by which current limitations may be overcome. We conclude that efforts to address this elusive issue have not yet been exhausted and that further explorations are likely to be worthwhile.     

Biocontrol of aerial plant diseases in agriculture and horticulture: current approaches and future prospects

Until recently, the majority of research on the biological control of aerial plant diseases was focused on control of bacterial pathogens. Such research led to the commercialization of the biocontrol agent Pseudomonas fluorescens A506, as BlightBan A506™, for control of fire blight of pear. In contrast, chemical fungicides typically have provided adequate control of most foliar fungal pathogens. However, fungicide resistance problems, concerns regarding pesticide residues and revocation of registration of certain widely used fungicides have led to increased activity in the development of biocontrol agents of foliar fungal pathogens. Much of this activity has centered around the use of Trichoderma spp and Gliocladium spp to control Botrytis cinerea on grape and strawberry. The biocontrol agent Trichoderma harzianum T39 is commercially available in Israel, as Trichodex ™, for control of grey mold in grapes and may soon be registered for use in the US. Also targeted primarily against a foliar disease of grapes, in this case powdery mildew caused by Uncinula necator, is the biocontrol agent Ampelomyces quisqualis AQ10, marketed as AQ^{10  TM} biofungicide. Another promising development in the area of foliar disease control, though one which is not yet commercialized, is the use of rhizobacteria as seed treatments to induce systemic resistance in the host plant, a strategy which can protect the plant against a range of bacterial and fungal pathogens. Received 06 February 1997/ Accepted in revised form 05 June 1997     

Podophyllotoxin: Current approaches to its biotechnological production and future challenges

Many plant‐derived agents are being used to treat cancer, including taxol, vinblastine, vincristine, or camptothecin and podophyllotoxin derivatives, among others. Plant biotechnology can provide a new tool for the production of anticancer agents but in spite of considerable efforts to produce vinblastine and vincristine in cell cultures and knowledge of the biosynthetic pathway of Catharanthus roseus alkaloids, the biotechnological production of taxol has only been achieved at an industrial level by companies such as Phyton Biotech and Cytoclonal Pharmaceutics. Podophyllotoxin was isolated as the active antitumor agent from the roots of Podophyllum species and more recently from the genus Linum and others. Etoposide, teniposide, and etophos are semi‐synthetic derivatives of podophyllotoxin and are used in the treatment of cancer. Biotechnological approaches, including the use of cell cultures, biotransformation, or metabolic engineering techniques to manipulate the biosynthetic pathway, represent an alternative for the production of podophyllotoxin and are discussed in this review.     

Cacao biotechnology: current status and future prospects

Theobroma cacao—The Food of the Gods, provides the raw material for the multibillion dollar chocolate industry and is also the main source of income for about 6 million smallholders around the world. Additionally, cocoa beans have a number of other nonfood uses in the pharmaceutical and cosmetic industries. Specifically, the potential health benefits of cocoa have received increasing attention as it is rich in polyphenols, particularly flavonoids. At present, the demand for cocoa and cocoa‐based products in Asia is growing particularly rapidly and chocolate manufacturers are increasing investment in this region. However, in many Asian countries, cocoa production is hampered due to many reasons including technological, political and socio‐economic issues. This review provides an overview of the present status of global cocoa production and recent advances in biotechnological applications for cacao improvement, with special emphasis on genetics/genomics, in vitro embryogenesis and genetic transformation. In addition, in order to obtain an insight into the latest innovations in the commercial sector, a survey was conducted on granted patents relating to T. cacao biotechnology.     

Energy crops: current status and future prospects

Energy crops currently contribute a relatively small proportion to the total energy produced from biomass each year, but the proportion is set to grow over the next few decades. This paper reviews the current status of energy crops and their conversion technologies, assesses their potential to contribute to global energy demand and climate mitigation over the next few decades, and examines the future prospects. Previous estimates have suggested a technical potential for energy crops of～400 EJ yr^?1 by 2050. In a new analysis based on energy crop areas for each of the IPCC SRES scenarios in 2025 (as projected by the IMAGE 2.2 integrated assessment model), more conservative dry matter and energy yield estimates and an assessment of the impact on non‐CO₂ greenhouse gases were used to estimate the realistically achievable potential for energy crops by 2025 to be between 2 and 22 EJ yr^?1, which will offset～100–2070 Mt CO₂‐eq. yr^?1. These results suggest that additional production of energy crops alone is not sufficient to reduce emissions to meet a 550 μmol mol^?1 atmospheric CO₂ stabilization trajectory, but is sufficient to form an important component in a portfolio of climate mitigation measures, as well as to provide a significant sustainable energy resource to displace fossil fuel resources. Realizing the potential of energy crops will necessitate optimizing the dry matter and energy yield of these crops per area of land through the latest biotechnological routes, with or without the need for genetic modification. In future, the co‐benefits of bioenergy production will need to be optimized and methods will need to be developed to extract and refine high‐value products from the feedstock before it is used for energy production.     

Mesophyll conductance to CO2: current knowledge and future prospects

During photosynthesis, CO2 moves from the atmosphere (C(a)) surrounding the leaf to the sub-stomatal internal cavities (C(i)) through stomata, and from there to the site of carboxylation inside the chloroplast stroma (C(c)) through the leaf mesophyll. The latter CO2 diffusion component is called mesophyll conductance (g(m)), and can be divided in at least three components, that is, conductance through intercellular air spaces (g(ias)), through cell wall (g(w)) and through the liquid phase inside cells (g(liq)). A large body of evidence has accumulated in the past two decades indicating that g(m) is sufficiently small as to significantly decrease C(c) relative to C(i), therefore limiting photosynthesis. Moreover, g(m) is not constant, and it changes among species and in response to environmental factors. In addition, there is now evidence that g(liq) and, in some cases, g(w), are the main determinants of g(m). Mesophyll conductance is very dynamic, changing in response to environmental variables as rapid or even faster than stomatal conductance (i.e. within seconds to minutes). A revision of current knowledge on g(m) is presented. Firstly, a historical perspective is given, highlighting the founding works and methods, followed by a re-examination of the range of variation of g(m) among plant species and functional groups, and a revision of the responses of g(m) to different external (biotic and abiotic) and internal (developmental, structural and metabolic) factors. The possible physiological bases for g(m), including aquaporins and carbonic anhydrases, are discussed. Possible ecological implications for variable g(m) are indicated, and the errors induced by neglecting g(m) when interpreting photosynthesis and carbon isotope discrimination models are highlighted. Finally, a series of research priorities for the near future are proposed.     

The rookie and the old-timer: challenges and future prospects

Molecular Biology Reports -     

Targeted protein degradation: current and future challenges

Traditional approaches in the development of small-molecule drugs typically aim to inhibit the biochemical activity of functional protein domains. In contrast, targeted protein degradation aims to reduce overall levels of disease-relevant proteins. Mechanistically, this can be achieved via chemical ligands that induce molecular proximity between an E3 ubiquitin ligase and a protein of interest, leading to ubiquitination and degradation of the protein of interest. This paradigm-shifting pharmacology promises to address several limitations inherent to conventional inhibitor design. Most notably, targeted protein degradation has the potential not only to expand the druggable proteome beyond the reach of traditional competitive inhibitors but also to develop therapeutic strategies of unmatched selectivity. This review briefly summarizes key challenges that remain to be addressed to deliver on these promises and to realize the full therapeutic potential of pharmacologic modulation of protein degradation pathways.     

Genomics-fueled approaches to current challenges in marine ecology

As a result of recent advances in genomic technology, a 'tool set' is emerging that can be used by marine ecologists to gain new perspectives on central questions in the field. Techniques such as gene expression profiling using DNA microarrays, when placed in an ecological context, stand to advance greatly our understanding of how organisms respond to abiotic and biotic stresses. Here, we target areas in which adding genomics to ecological and physiological investigations will significantly advance our understanding of crucial issues ranging from the general biological effects of environmental temperature changes on individuals and communities to the interactions between symbionts in coral bleaching. At a time when both short- and long-term perturbations of marine ecosystems are increasing in severity, this kind of integrative approach could generate new and exciting hypotheses about the functioning of marine organisms and communities.     

Protein-ligand docking: current status and future challenges

Understanding the ruling principles whereby protein receptors recognize, interact, and associate with molecular substrates and inhibitors is of paramount importance in drug discovery efforts. Protein-ligand docking aims to predict and rank the structure(s) arising from the association between a given ligand and a target protein of known 3D structure. Despite the breathtaking advances in the field over the last decades and the widespread application of docking methods, several downsides still exist. In particular, protein flexibility-a critical aspect for a thorough understanding of the principles that guide ligand binding in proteins-is a major hurdle in current protein-ligand docking efforts that needs to be more efficiently accounted for. In this review the key concepts of protein-ligand docking methods are outlined, with major emphasis being given to the general strengths and weaknesses that presently characterize this methodology. Despite the size of the field, the principal types of search algorithms and scoring functions are reviewed and the most popular docking tools are briefly depicted. Recent advances that aim to address some of the traditional limitations associated with molecular docking are also described. A selection of hand-picked examples is used to illustrate these features.     

Carriers and channels: current progress and future prospects

Recent advances in the understanding of biological transport and in the design of artificial transport systems have resulted from the structural elucidation of the K⁺ ion channel and from synthesis of artificial receptors for cations and anions, as well as neutral and zwitterionic organic molecules. Sensors, gated carriers, and self-assembling capsules and nanotubes are all important offsprings of current efforts to mimic natural transport across biomembranes.     

Molecular imprinting technology: challenges and prospects for the future

Molecular imprinting is a technique for the fabrication of biomimetic polymeric recognition sites or “plastic antibodies/receptors” which is attracting rapidly increasing interest. By this technology, recognition matrices can be prepared which possess high substrate selectivity and specificity. In the development of this technology, several applications have been foreseen in which imprinted materials may be exchanged for natural recognition elements. Thus, molecularly imprinted polymers have been used as antibody/receptor binding mimics in immunoassay-type analyses, as enzyme mimics in catalytic applications and as recognition matrices in biosensors. The best developed application area for imprinted materials, though, has been as stationary phases for chromatography, in general, and chiral chromatography, in particular. This review seeks to highlight some of the more intriguing advantages of the technique as well as pointing out some of the difficulties encountered. The prospects for future development will also be considered. Chirality 10:195–209, 1998. © 1998 Wiley-Liss, Inc.     

Vitamin K series: current status and future prospects

The Vitamin K series, particularly menaquinone, have been attracting research attention, due to the potential in reducing both osteoporosis and cardiovascular diseases. This review provides an overview of the types of vitamin K and their health benefits. This is followed by a critical review of the various biotechnological approaches used in the production of menaquinone, including solid and liquid state fermentations, extraction and recovery. The currently available market information is summarized and future growth prospects are discussed. Recommendations are also given for areas of future research in order to improve the production process for menaquinone and reduce costs.     

The nitrile-degrading enzymes: current status and future prospects

Nitrile-converting enzymes are becoming commonplace in the synthesis of pharmaceuticals and commodity chemicals. These versatile biocatalysts have potential applications in different fields including synthetic biocatalysis and bioremediation. This review attempts to describe in detail the three major classes of nitrile-converting enzymes, namely nitrilases, nitrile hydratases and amidases. Various aspects of these enzymes including their occurrence, mechanism of action, characteristics and applicability in different sectors have been elaborately elucidated. Cloning of genes related to nitrile-converting enzymes is also discussed.     

Electrophysiology and glaucoma: current status and future challenges

Visual electrophysiology allows non-invasive monitoring of the function of most processing stages along the visual pathway. Here, we consider which of the available methods provides the most information concerning glaucomatous optic nerve disease. The multifocal electroretinogram (ERG), although often employed, is less affected in glaucoma than two direct measurements of retinal ganglion cell function, namely the pattern ERG (PERG) and the photopic negative response (PhNR) of the ERG. For the PERG, longitudinal studies have been reported, suggesting that this method can be used for the early detection of glaucoma; for the PhNR, no longitudinal study is available as yet. The multifocal PERG can spatially resolve ganglion cell function but its glaucomatous reduction is typically panretinal, even with only local field changes and so, its topographic resolution is of no advantage in glaucoma. The multifocal visual evoked potential promises objective perimetry and shows sensitivity and specificity comparable with standard automated perimetry but has not been established as a routine tool to date.