16 research outputs found

    Avances en los estudios arqueolĂłgicos, geoarqueolĂłgicos y paleoambientales en las Sierras Orientales de Tandilia. Resultados preliminares de los sitios Alero El Mirador y Abrigo La Grieta

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    This paper presents the characteristics of the archaeological record of two sites recently taken up, called Alero El Mirador and Abrigo La Grieta. The study of different proxy data like lithic assemblages, zooarchaeological and paleoenvironmental record (obtained by diatoms, phytoliths and anthracology inferences) and their relationship to stratigraphic units, allows us to hypothesize anthropic management aspects of local natural resources and paleoclimatic events occurred in the eastern of Tandilia hill during different moments of the Pleistocene-Holocene archaeological sequence.Este trabajo presenta las características de los registros arqueológicos de dos sitios recientemente retomados, denominados Alero El Mirador y Abrigo La Grieta. Se dan a conocer los resultados del análisis de los conjuntos líticos, del registro zooarqueológico y paleoambiental (obtenidos a partir de la evidencias de diatomeas, antracología y fitolitos), y su relación con las unidades estratigráficas. Esta información proxy permite hipotetizar aspectos del manejo antrópico de recursos naturales locales y de eventos paleoclimáticos ocurridos en el sector serrano de Tandilia oriental durante distintos tramos de la secuencia Pleistoceno-Holoceno

    Two-dimensional 1H NMR study of recombinant insect defensin A in water: resonance assignments, secondary structure and global folding.

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    International audienceA 500 MHz 2D 1H NMR study of recombinant insect defensin A is reported. This defense protein of 40 residues contains 3 disulfide bridges, is positively charged and exhibits antibacterial properties. 2D NMR maps of recombinant defensin A were fully assigned and secondary structure elements were localized. The set of NOE connectivities, 3JNH-alpha H coupling constants as well as 1H/2H exchange rates and delta delta/delta T temperature coefficients of NH protons strongly support the existence of an alpha-helix (residues 14-24) and of an antiparallel beta-sheet (residues 27-40). Models of the backbone folding were generated by using the DISMAN program and energy refined by using the AMBER program. This was done on the basis of: (i) 133 selected NOEs, (ii) 21 dihedral restraints from 3JNH-alpha H coupling constants, (iii) 12 hydrogen bonds mostly deduced from 1H/2H exchange rates or temperature coefficients, in addition to 9 initial disulfide bridge covalent constraints. The two secondary structure elements and the two bends connecting them involve approximately 70% of the total number of residues, which impose some stability in the C-terminal part of the molecule. The remaining N-terminal fragment forms a less well defined loop. This spatial organization, in which a beta-sheet is linked to an alpha-helix by two disulfide bridges and to a large loop by a third disulfide bridge, is rather similar to that found in scorpion charybdotoxin and seems to be partly present in several invertebrate toxins
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