73 research outputs found

    Landscape science: a Russian geographical tradition

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    The Russian geographical tradition of landscape science (landshaftovedenie) is analyzed with particular reference to its initiator, Lev Semenovich Berg (1876-1950). The differences between prevailing Russian and Western concepts of landscape in geography are discussed, and their common origins in German geographical thought in the late nineteenth and early twentieth centuries are delineated. It is argued that the principal differences are accounted for by a number of factors, of which Russia's own distinctive tradition in environmental science deriving from the work of V. V. Dokuchaev (1846-1903), the activities of certain key individuals (such as Berg and C. O. Sauer), and the very different social and political circumstances in different parts of the world appear to be the most significant. At the same time it is noted that neither in Russia nor in the West have geographers succeeded in specifying an agreed and unproblematic understanding of landscape, or more broadly in promoting a common geographical conception of human-environment relationships. In light of such uncertainties, the latter part of the article argues for closer international links between the variant landscape traditions in geography as an important contribution to the quest for sustainability

    Recommendations for Addressing Priority Io Science in the Next Decade

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    Io is a priority destination for solar system exploration. The scope and importance of science questions at Io necessitates a broad portfolio of research and analysis, telescopic observations, and planetary missions - including a dedicated New Frontiers class Io mission

    The Science Case for Io Exploration

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    Io is a priority destination for solar system exploration, as it is the best natural laboratory to study the intertwined processes of tidal heating, extreme volcanism, and atmosphere-magnetosphere interactions. Io exploration is relevant to understanding terrestrial worlds (including the early Earth), ocean worlds, and exoplanets across the cosmos

    The heat-treatment induced reduction of the pat gene encoded herbicide resistance in Nicotiana tabacum is influenced by the transgene sequence

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    Kohne S, Neumann K, Pühler A, Broer I. The heat-treatment induced reduction of the pat gene encoded herbicide resistance in Nicotiana tabacum is influenced by the transgene sequence. JOURNAL OF PLANT PHYSIOLOGY. 1998;153(5-6):631-642.After 10 days of cultivation at 37 degrees C, the herbicide resistance encoded by the chimaeric pat41 gene (coding region from Streptomyces viridochromogenes fused to the 823 bp CaMV35S promoter) was strongly reduced in all of the 27 independent transgenic Nicotiana tabacum SRI lines analyzed. This reversible reduction occurred in sterile and unsterile culture in the first and second generation and even when the overnight temperature was reduced to 24 degrees C. Neither the enzyme activity, the protein nor the pat41 specific RNA could be detected in the heat treated plants, regardless of the number of copies and the hemior homozygous state. In contrast to this, the expression of the synthetic patS coding region fused to the 534 bp CaMV35S promoter and coding for essentially the same protein, was stable in heat treated plants. The exchange of the GC rich coding region of the pat41 gene by the AT rich synthetic DNA fragment carrying the patS coding region led to the stabilization of the specific RNA steady state level. However, the presence of the transgene-encoded protein at 37 degrees C could only be achieved by using specific 5' and 3' untranslated regions of the synthetic patS gene

    Specialized Yeast Ribosomes: A Customized Tool for Selective mRNA Translation

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    Evidence is now accumulating that sub-populations of ribosomes - so-called specialized ribosomes - can favour the translation of subsets of mRNAs. Here we use a large collection of diploid yeast strains, each deficient in one or other copy of the set of ribosomal protein (RP) genes, to generate eukaryotic cells carrying distinct populations of altered ‘specialized’ ribosomes. We show by comparative protein synthesis assays that different heterologous mRNA reporters based on luciferase are preferentially translated by distinct populations of specialized ribosomes. These mRNAs include reporters carrying premature termination codons (PTC) thus allowing us to identify specialized ribosomes that alter the efficiency of translation termination leading to enhanced synthesis of the wild-type protein. This finding suggests that these strains can be used to identify novel therapeutic targets in the ribosome. To explore this further we examined the translation of the mRNA encoding the extracellular matrix protein laminin ?3 (LAMB3) since a LAMB3-PTC mutant is implicated in the blistering skin disease Epidermolysis bullosa (EB). This screen identified specialized ribosomes with reduced levels of RP L35B as showing enhanced synthesis of full-length LAMB3 in cells expressing the LAMB3-PTC mutant. Importantly, the RP L35B sub-population of specialized ribosomes leave both translation of a reporter luciferase carrying a different PTC and bulk mRNA translation largely unaltered
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