Reformation of functional liver polyribosomes from ribosome monomers in the absence of RNA synthesis   总被引：2，自引：0，他引：2  

G A Stewart  E Farber 《Science (New York, N.Y.)》1967,157(784):67-69

The administration to rats of the ethyl analog of methionine, ethionine, results in the rapid decrease in the hepatic concentration of adenosine triphosphate followed by an extensive disaggregation of polysomes to ribosome monomers and a concomitant inhibition of protein synthesis. These effects are readily reversed by the injection of methionine or precursors of adenine nucleotides such as adenine. The reformation of liver polyribosomes in such animals following the administration of adenine plus methionine was found to occur under conditions in which new RNA synthesis was markedly inhibited. Free messenger RNA without attached ribosomes must be capable of remaining functionally active in the liver cytoplasm for many hours.  相似文献   

Genetic regulation of conidiation in Trichoderma hamatun          下载免费PDF全文

Johanna Steyaert　 Travis Glare　 Alison Stewart　 Margaret Carpenter　 Hayley Ridgway 《浙江大学学报(农业与生命科学版)》2004,30(4):442-442

Achieving a balance between vegetative growth and spore production is essential for successful biocontrol by fungi. Low sporulation rates in the field can result in poor establishment and survival,whereas failure of conidia to recognise hosts can lead to persistence without efficacy. Commercial biocontrol products involve bulk preparations of conidia, however considerable variability in conidiation rates exists between biocontrol agents, which can restrict choice of strain for production. The majority of studies on Trichoderma conidiation have focused on the species T. viride and T. atroviride.These species form conidia in response to blue and near-UV light and/or nutrient deprivation and conidiation proceeds in a highly co-ordinated fashion, however relatively little is known on the genetic basis of Trichoderrma conidiation. In addition, whilst photoconidiation appears to be a general response detailed studies in other Trichoderma species are absent. In this study, conidiation in the lesser known biocontrol species T. hamatum is being investigated using a combined morphological and molecular approach. In contrast to T. atroviride, conidiation in response to blue-light was weaker and variable and suggested that additional triggers may be required for the T. hamatum photoresponse. A series of comparative photoconidiation assays are currently being undertaken investigating the effect of inoculum type and abiotic factors on timing and intensity of the response.Results will be discussed in relation to the current knowledge on conidial morphogenesis in Trichoderma. In addition to these morphological assays, a selection of genes implicated in sporulation and the blue-light responses are currently being isolated and characterised from T. hamatum. Two genes, phr1 and cmp1 , which were isolated previously from T. atroviride will be used as early and late markers of gene expression during the photoresponse in T. hamatum in order to define time points for harvesting comparable stage-specific RNA from T. hamatum and T. atroviride. Using degenerate PCR putative sporulation gene orthologues have also been identified in T. hamatum.Work is currently underway to isolate genomic clones of these genes from T. hamatum and T.atroviride. Sequence and expression analysis of orthologues, including expression in response to abiotic factors will be presented and discussed in relation to the current knowledge of the molecular basis of conidiation in Trichoderma and other filamentous fungi.……  相似文献   

Capturing the Sustainability Agenda: Organic Foods and Media Discourses on Food Scares, Environment, Genetic Engineering, and Health     

Stewart Lockie 《Agriculture and Human Values》2006,23(3):313-323

This paper undertakes a content analysis of newspaper articles from Australia, the UK, and the US concerned with a variety of issues relevant to sustainable food and agriculture from 1996 to 2002. It then goes on to identify the various ways in which sustainability, organic food and agriculture, genetic engineering, genetically modified foods, and food safety are framed both in their own terms and in relation to each other. It finds that despite the many competing approaches to sustainability found in scientific and agricultural production discourses, media discourses tend to reduce this complexity to a straightforward conflict between organic and conventional foods. Despite regular reporting of viewpoints highly critical of organic food and agriculture, this binary opposition produces discourses in which organic foods are seen as more-or-less synonymous with safety, naturalness and nutrition, and their alternatives as artificial, threatening, and untrustworthy. Particularly controversial food-related issues such as genetic engineering, food scares, chemical residues, and regulatory failure are treated as part of the same problem to which organic food offers a trustworthy and easily understood solution. Stewart Lockie is Associate Professor of Rural and Environmental Sociology and Associate Dean (Research) in the Faculty of Sciences, Engineering and Health at Central Queensland University. His main research interests lie in the greening of food and agriculture, food commodity networks, and natural resource management. Recent co-edited books include Rurality Bites: The Social and Environmental Transformation of Rural Australia and Consuming Foods, Sustaining Environments.  相似文献   

Structural biology. Nuclear trafficking     

Stewart M 《Science (New York, N.Y.)》2003,302(5650):1513-1514

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A RELATION OF ATOMIC WEIGHTS TO ATOMIC NUMBERS,AND A SUGGESTED STRUCTURE OF ATOMIC NUCLEI     

Stewart JQ 《Science (New York, N.Y.)》1917,46(1197):568-569

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Region-specific neural induction of an engrailed protein by anterior notochord in Xenopus     

A Hemmati-Brivanlou  R M Stewart  R M Harland 《Science (New York, N.Y.)》1990,250(4982):800-802

Anterior-specific neural induction can be assayed by means of an antibody that recognizes the Xenopus homeobox-containing protein En-2. The En-2 antigen is an excellent early marker, since it is present as a discrete band in the anterior neural plate of neurula embryos. Regional induction was assayed by combining dorsal mesoderm with competent ectoderm. Anterior notochord from the early neurula induced En-2 frequently, while posterior notochord induced En-2 less frequently. Presumptive somitic mesoderm and presumptive head mesoderm, though they induced neural tissue, were not strong inducers of En-2. Thus, anterior notochord may be the primary mesodermal tissue responsible for the patterning of the anterior neural plate.  相似文献   

THE PISTILLATE SPIKELET IN ZEA MAYS     

Stewart A 《Science (New York, N.Y.)》1915,42(1089):694-695

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Paramagnetic ions in zoisite     

Hutton DR  Troup GJ  Stewart GA 《Science (New York, N.Y.)》1971,174(4015):1259

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Synthesis of Rubber by Fungi     

Stewart WD  Wachtel WL  Shipman JJ  Yanko JA 《Science (New York, N.Y.)》1955,122(3183):1271-1272

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SECTION B--PHYSICS     

Stewart GW 《Science (New York, N.Y.)》1920,51(1318):352

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