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"Cells do not care about mathematics" thus concluded a biologist friend after a discussion on the future of biology. And indeed, why should they care? But if we exchange the word "cell" with "rock", "Moon" or "electrons", do we have to change the sentence also? Starting from this line of thought, we review some recent developments in understanding the stochastic behavior of biological systems. We emphasize the importance of a molecular Signal Generator in the study of genetic networks.  相似文献   

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A biological system, like any complex system, blends stochastic and deterministic features, displaying properties of both. In a certain sense, this blend is exactly what we perceive as the “essence of complexity” given we tend to consider as non-complex both an ideal gas (fully stochastic and understandable at the statistical level in the thermodynamic limit of a huge number of particles) and a frictionless pendulum (fully deterministic relative to its motion). In this commentary we make the statement that systems biology will have a relevant impact on nowadays biology if (and only if) will be able to capture the essential character of this blend that in our opinion is the generation of globally ordered collective modes supported by locally stochastic atomisms.  相似文献   

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McKay R  Kittappa R 《Neuron》2008,58(5):659-661
Three papers recently published in Nature Medicine provide the most detailed analyses of fetal midbrain grafts in patients with Parkinson's disease. Some of the results are surprising and suggest a new wave of questions aimed at both the value of cell therapy and the nature of the disease itself.  相似文献   

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Transgenic insecticidal plants based onBacillus thuringiensis (Bt) endotoxins, on proteinase inhibitors and on lectins, and transgenic herbicide tolerant plants are widely used in modern agriculture. The results of the studies on likelihood and non-likelihood of adverse effects of transgenic plants on the environment including: (i) effects on nontarget species; (ii) invasiveness; (iii) potential for transgenes to ‘escape’ into the environment by horizontal gene transfer; and (iv) adverse effects on soil biota are reviewed. In general, it seems that large-scale implementation of transgenic insecticidal and herbicide tolerant plants do not display considerable negative effects on the environments and, moreover, at least some transgenic plants can improve the corresponding environments and human health because their production considerably reduces the load of chemical insecticides and herbicides.  相似文献   

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Taxol (paclitaxel) is widely used for the treatment of various kinds of cancers. Originally, the major source of taxol was bark of the Pacific yew tree (Taxus brevifolia). However, this proved devastating to natural populations of the trees. To protect the Pacific yew, alternatives to the use of trees are sought. One solution is the use of taxol or its precursors derived from fungi. A large number of endophytic fungi that reside within healthy plants have been reported to be taxol producers. However, fungal epiphytes, pathogens and saprophytes have also been found to produce taxol. Several strains of fungi belonging to species Metarhizium anisopliae and Cladosporium cladosporioides MD2 are very promising, producing taxol at levels up to 800 μg/L. This review examines the potential for production of taxol from fungi. The biology of taxol synthesis in fungi and measures which may improve taxol yield are also discussed.  相似文献   

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Disease, through the ages, has been considered as a 'visitation' from afar to the body or as 'disequilibrium' of an internal order. In practical terms, these two concepts of disease have generated a nosology, that is a classification of disease states. Genetics, in its dazzling recent advances, has opened another conceptual framework: disease is an individual event, inasmuch as our growing understanding of the genetic 'terrain' makes all subjects true individuals. Hence, it is time to abandon the old conceptual dichotomy for a Hegelian synthesis: there are no diseases (either as visitation or disequilibrium) only diseased individuals.  相似文献   

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In the highly competitive environment of contemporary pharmaceutical research, natural products provide a unique element of molecular diversity and biological functionality which is indispensable for drug discovery. The emergence of strategies to deliver drug leads from natural products within the same time frame as synthetic chemical screening has eliminated a major limitation of the past. At a more functional level, the application of molecular genetics techniques has permitted the manipulation of biosynthetic pathways for the generation of novel chemical species as well as rendering hitherto uncultivatable microorganisms accessible for secondary metabolite generation. These developments augur well for an industry confronted with the challenge of finding lead compounds directed at the plethora of new targets arising from genomics projects. The exploitation of structural chemical databases comprising a wide variety of chemotypes, in conjunction with databases on target genes and proteins, will facilitate the creation of new chemical entities through computational molecular modelling for pharmacological evaluation.  相似文献   

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A new source of endothelial progenitor cells--vascular biology redefined?   总被引:3,自引:0,他引:3  
The initial discovery of endothelial progenitor cells (EPCs) in tandem with emerging concepts in stem cell biology has generated enormous interest and excitement in fields as diverse as tissue engineering, regenerative medicine, and tumor and vascular biology. A recent paper by Ingram et al. identifies a complete hierarchy of EPCs in the vessel wall, providing a new framework for classification of cells supporting endopoiesis akin to that previously established for hematopoiesis. This could have fundamental implications for our understanding of the role of the endothelium and, more specifically, the role of EPC interfacing with the vessel wall in health and disease.  相似文献   

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Biological invasion is increasingly recognized as one of the greatest threats to biodiversity. Using ensemble forecasts from species distribution models to project future suitable areas of the 100 of the world's worst invasive species defined by the International Union for the Conservation of Nature, we show that both climate and land use changes will likely cause drastic species range shifts. Looking at potential spatial aggregation of invasive species, we identify three future hotspots of invasion in Europe, northeastern North America, and Oceania. We also emphasize that some regions could lose a significant number of invasive alien species, creating opportunities for ecosystem restoration. From the list of 100, scenarios of potential range distributions show a consistent shrinking for invasive amphibians and birds, while for aquatic and terrestrial invertebrates distributions are projected to substantially increase in most cases. Given the harmful impacts these invasive species currently have on ecosystems, these species will likely dramatically influence the future of biodiversity.  相似文献   

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The pH of the surface ocean is changing as a result of increases in atmospheric carbon dioxide (CO2), and there are concerns about potential impacts of lower pH and associated alterations in seawater carbonate chemistry on the biogeochemical processes in the ocean. However, it is important to place these changes within the context of pH in the present-day ocean, which is not constant; it varies systematically with season, depth and along productivity gradients. Yet this natural variability in pH has rarely been considered in assessments of the effect of ocean acidification on marine microbes. Surface pH can change as a consequence of microbial utilization and production of carbon dioxide, and to a lesser extent other microbially mediated processes such as nitrification. Useful comparisons can be made with microbes in other aquatic environments that readily accommodate very large and rapid pH change. For example, in many freshwater lakes, pH changes that are orders of magnitude greater than those projected for the twenty second century oceans can occur over periods of hours. Marine and freshwater assemblages have always experienced variable pH conditions. Therefore, an appropriate null hypothesis may be, until evidence is obtained to the contrary, that major biogeochemical processes in the oceans other than calcification will not be fundamentally different under future higher CO2/lower pH conditions.  相似文献   

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Abstract

IPN (Institut für die Pädagogik der Naturwissenschaften/Institute for Science Education) in Kiel has developed single curriculum units since 1969 showing that certain innovative aims, methods, media, and content of biology teaching are practicable in schools. These units are being published now as a flexible ‘unit bank’ which can either be adopted as a whole or the individual units, or parts thereof, fitted into existing syllabuses.  相似文献   

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