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101.
Sunita A. Ramesh Stephen D. Tyerman Matthew Gilliham Bo Xu 《Cellular and molecular life sciences : CMLS》2017,74(9):1577-1603
The role of γ-aminobutyric acid (GABA) as a signal in animals has been documented for over 60 years. In contrast, evidence that GABA is a signal in plants has only emerged in the last 15 years, and it was not until last year that a mechanism by which this could occur was identified—a plant ‘GABA receptor’ that inhibits anion passage through the aluminium-activated malate transporter family of proteins (ALMTs). ALMTs are multigenic, expressed in different organs and present on different membranes. We propose GABA regulation of ALMT activity could function as a signal that modulates plant growth, development, and stress response. In this review, we compare and contrast the plant ‘GABA receptor’ with mammalian GABAA receptors in terms of their molecular identity, predicted topology, mode of action, and signalling roles. We also explore the implications of the discovery that GABA modulates anion flux in plants, its role in signal transduction for the regulation of plant physiology, and predict the possibility that there are other GABA interaction sites in the N termini of ALMT proteins through in silico evolutionary coupling analysis; we also explore the potential interactions between GABA and other signalling molecules. 相似文献
102.
Genome shuffling leads to rapid phenotypic improvement in bacteria 总被引:51,自引:0,他引:51
For millennia, selective breeding, on the basis of biparental mating, has led to the successful improvement of plants and animals to meet societal needs. At a molecular level, DNA shuffling mimics, yet accelerates, evolutionary processes, and allows the breeding and improvement of individual genes and subgenomic DNA fragments. We describe here whole-genome shuffling; a process that combines the advantage of multi-parental crossing allowed by DNA shuffling with the recombination of entire genomes normally associated with conventional breeding. We show that recursive genomic recombination within a population of bacteria can efficiently generate combinatorial libraries of new strains. When applied to a population of phenotypically selected bacteria, many of these new strains show marked improvements in the selected phenotype. We demonstrate the use of this approach through the rapid improvement of tylosin production from Streptomyces fradiae. This approach has the potential to facilitate cell and metabolic engineering and provide a non-recombinant alternative to the rapid production of improved organisms. 相似文献
103.
John L. Turner 《Journal of forecasting》2004,23(7):513-539
This article introduces a novel framework for analysing long‐horizon forecasting of the near non‐stationary AR(1) model. Using the local to unity specification of the autoregressive parameter, I derive the asymptotic distributions of long‐horizon forecast errors both for the unrestricted AR(1), estimated using an ordinary least squares (OLS) regression, and for the random walk (RW). I then identify functions, relating local to unity ‘drift’ to forecast horizon, such that OLS and RW forecasts share the same expected square error. OLS forecasts are preferred on one side of these ‘forecasting thresholds’, while RW forecasts are preferred on the other. In addition to explaining the relative performance of forecasts from these two models, these thresholds prove useful in developing model selection criteria that help a forecaster reduce error. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
104.
中国的人类学家,不管是投师于国外或国内,至今为止,几乎不能使他们的发现对世界其他地区的人类学有用处。中国人类学的问题不是不够地方性,而是太地方性了。中国人类学当前所需要的是经过一个时期的本土化发展,然而再走出来,参与世界性对话。 相似文献
105.
土壤质量及其评价指标 总被引:22,自引:1,他引:21
在提出土壤质量概念的共性中,重要的是土壤在现今和将来均能有效地挥功能,在这种能力的基础上,认为土壤质量评价指标不要简化,要多层次,应满足5个标准,并对现有的物理,化学,生物评价指标的实用性有其优缺点进行了分析。参24。 相似文献
106.
107.
Stephen Farr 《Systemic Practice and Action Research》1991,4(1):47-58
This paper describes how British Telecom's Training Department has been using Systems Thinking over the last few years and has started introducing Systems concepts and methodologies to a wider audience of operational managers within. The paper explores some of the reasons for British Telecom to adopt Systems Thinking and describes the application of Soft Systems Methodology (SSM) to a particular project within Training Department. The paper also describes the design and delivery of the Introduction to Systems Thinking course which is now part of British Telecom's core program of management training. 相似文献
108.
109.
Stephen G. Alter 《Annals of science》2013,70(2):235-250
In The Origin of Species, Charles Darwin famously accounted for the lack of fossil evidence in support of species evolution on the grounds that the fossil record is naturally incomplete. This essay examines a similar argument that Darwin applied to his analogy between natural and artificial selection: the scarcity of data about the historical backgrounds of domestic breeds was the natural by-product of an extremely gradual change process. The point was to enhance the ability of the artificial selection analogy to suggest that nature's species had undergone a similar transformation. Darwin did not depend on this negative inference alone, however, for in his writings he included whatever information he could find about the actual histories of particular breeds. A comparison with Darwin's treatment of the fossil record suggests the reasonableness of this combined use of opposite kinds of evidence to establish a single point. The comparison also suggests the unique qualities of negative inference as applied to the breeding analogy. 相似文献
110.