977 resultados para Bentley, Richard, 1662-1742.
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L-R: Fr. Francis X. Canfield, Monsignor Henry Donnelly, Albert Hyma, F. Clever Bald
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L-R: F. Clever Bald, Fr. Francis X. Canfield, Monsignor Henry Donnelly, Albert Hyma,
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L-R: Fr. Francis X. Canfield, Monsignor Henry Donnelly, Albert Hyma, F. Clever Bald
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Mode of access: Internet.
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The exponential growth of studies on the biological response to ocean acidification over the last few decades has generated a large amount of data. To facilitate data comparison, a data compilation hosted at the data publisher PANGAEA was initiated in 2008 and is updated on a regular basis (doi:10.1594/PANGAEA.149999). By January 2015, a total of 581 data sets (over 4 000 000 data points) from 539 papers had been archived. Here we present the developments of this data compilation five years since its first description by Nisumaa et al. (2010). Most of study sites from which data archived are still in the Northern Hemisphere and the number of archived data from studies from the Southern Hemisphere and polar oceans are still relatively low. Data from 60 studies that investigated the response of a mix of organisms or natural communities were all added after 2010, indicating a welcomed shift from the study of individual organisms to communities and ecosystems. The initial imbalance of considerably more data archived on calcification and primary production than on other processes has improved. There is also a clear tendency towards more data archived from multifactorial studies after 2010. For easier and more effective access to ocean acidification data, the ocean acidification community is strongly encouraged to contribute to the data archiving effort, and help develop standard vocabularies describing the variables and define best practices for archiving ocean acidification data.
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Nucleoside diphosphate kinases play a crucial role in the purine-salvage pathway of trypanosomatid protozoa and have been found in the secretome of Leishmania sp., suggesting a function related to host-cell integrity for the benefit of the parasite. Due to their importance for housekeeping functions in the parasite and by prolonging the life of host cells in infection, they become an attractive target for drug discovery and design. In this work, we describe the first structural characterization of nucleoside diphosphate kinases b from trypanosomatid parasites (tNDKbs) providing insights into their oligomerization, stability and structural determinants for nucleotide binding. Crystallographic studies of LmNDKb when complexed with phosphate, AMP and ADP showed that the crucial hydrogen-bonding residues involved in the nucleotide interaction are fully conserved in tNDKbs. Depending on the nature of the ligand, the nucleotide-binding pocket undergoes conformational changes, which leads to different cavity volumes. SAXS experiments showed that tNDKbs, like other eukaryotic NDKs, form a hexamer in solution and their oligomeric state does not rely on the presence of nucleotides or mimetics. Fluorescence-based thermal-shift assays demonstrated slightly higher stability of tNDKbs compared to human NDKb (HsNDKb), which is in agreement with the fact that tNDKbs are secreted and subjected to variations of temperature in the host cells during infection and disease development. Moreover, tNDKbs were stabilized upon nucleotide binding, whereas HsNDKb was not influenced. Contrasts on the surface electrostatic potential around the nucleotide-binding pocket might be a determinant for nucleotide affinity and protein stability differentiation. All these together demonstrated the molecular adaptation of parasite NDKbs in order to exert their biological functions intra-parasite and when secreted by regulating ATP levels of host cells.