4,599 research outputs found

    The regions of the sequence most exposed to the solvent within the amyloidogenic state of a protein initiate the aggregation process.

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    Formation of misfolded aggregates is an essential part of what proteins can do. The process of protein aggregation is central to many human diseases and any aggregating event needs to be prevented within a cell and in protein design. In order to aggregate, a protein needs to unfold its native state, at least partially. The conformational state that is prone to aggregate is difficult to study, due to its aggregating potential and heterogeneous nature. Here, we use a systematic approach of limited proteolysis, in combination with electrospray ionisation mass spectrometry, to investigate the regions that are most flexible and solvent-exposed within the native, ligand-bound and amyloidogenic states of muscle acylphosphatase (AcP), a protein previously shown to form amyloid fibrils in the presence of trifluoroethanol. Seven proteases with different degrees of specificity have been used for this purpose. Following exposure to the aggregating conditions, a number of sites along the sequence of AcP become susceptible to proteolytic digestion. The pattern of proteolytic cleavages obtained under these conditions is considerably different from that of the native and ligand-bound conformations and includes a portion within the N-terminal tail of the protein (residues 6-7), the region of the sequence 18-23 and the position 94 near the C terminus. There is a significant overlap between the regions of the sequence found to be solvent-exposed from the present study and those previously identified to be critical in the rate-determining steps of aggregation from protein engineering approaches. This indicates that a considerable degree of solvent exposure is a feature of the portions of a protein that initiate the process of aggregation

    Assessment of the Triage System in a Pediatric Emergency Department. A pilot study on critical code

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    Introduction. In Italy, triage involves assigning a priority color code to patients arriving at the hospital Emergency Department: red (very critical), yellow (moderately critical), green (not very critical), and white (not critical). Methods. This study was aimed at assessing the triage system in the Emergency Department of ?Giannina Gaslini? Children? s Hospital in Genoa, Italy. The authors examined 130 triage forms assigning a yellow code in 2003, in order to determine whether they had been correctly filled in with regard to the detection of vital parameters, identification of main symptoms and color code assignment. Results. Results showed that vital signs were recorded in 94% of patients, main symptoms were identified in 97%, and a yel- low code was assigned according to hospital guidelines in 84%. The percentage of underestimation (3.2%) was higher than that reported in the literature (2%). Conclusions. The study shows the need to improve compliance with the guidelines and to evaluate green and white codes

    BCR-ABL residues interacting with ponatinib are critical to preserve the tumorigenic potential of the oncoprotein

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    Patients with chronic myeloid leukemia in whom tyrosine kinase inhibitors (TKIs) fail often present mutations in the BCR-ABL catalytic domain. We noticed a lack of substitutions involving 4 amino acids (E286, M318, I360, and D381) that form hydrogen bonds with ponatinib. We therefore introduced mutations in each of these residues, either preserving or altering their physicochemical properties. We found that E286, M318, I360, and D381 are dispensable for ABL and BCR-ABL protein stability but are critical for preserving catalytic activity. Indeed, only a "conservative" I360T substitution retained kinase proficiency and transforming potential. Molecular dynamics simulations of BCR-ABLI360T revealed differences in both helix αC dynamics and protein-correlated motions, consistent with a modified ATP-binding pocket. Nevertheless, this mutant remained sensitive to ponatinib, imatinib, and dasatinib. These results suggest that changes in the 4 BCR-ABL residues described here would be selected against by a lack of kinase activity or by maintained responsiveness to TKIs. Notably, amino acids equivalent to those identified in BCR-ABL are conserved in 51% of human tyrosine kinases. Hence, these residues may represent an appealing target for the design of pharmacological compounds that would inhibit additional oncogenic tyrosine kinases while avoiding the emergence of resistance due to point mutations.This work was supported by an investigator grant to P.V. from Associazione Italiana per la Ricerca sul Cancro (AIRC) and by funding from the Biotechnology and Biological Sciences Research Council (BB/I023291/1 and BB/H018409/1 to AP and FF). P.B. is the recipient of an AIRC - Marie Curie fellowship

    Vinculando la danza y la educación: el caso del internado Beatriz Hernández

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    Informe que muestra el proceso de sistematización y teorización de gestión del conocimiento realizado para instalar el proyecto “La danza clásica desde la mirada educativa: una propuesta para la educación del cuerpo” en el internado para niñas de bajos recursos Beatriz Hernández, el cual depende de la Secretaría de Educación Jalisco (SEJ). Este proyecto tuvo el objetivo de diseñar un método educativo basado en la danza y en la conversación para incidir en el conocimiento del cuerpo, el desarrollo cognitivo y el socioafectivo de las alumnas del internado y lograr instalar este método como parte del currículo de la institución. Los resultados de este proyecto permiten tener un nuevo acercamiento al conocimiento de la práctica de la danza como herramienta metodológica para favorecer, por su naturaleza física, expresiva y cognitiva, la integración de mente, cuerpo y emociones. Además, posibilita abrir espacios para ampliar la visión tradicional de los procesos de cognición, aporta nuevos recursos a los normalmente utilizados en el currículo escolar, abre la reflexión sobre el cuerpo como medio de exploración y apropiación de los conocimientos y contribuye a la vinculación de la educación y el arte al proponer la danza como estrategia de formación en el currículo escolar. *A lo largo de este trabajo, la autora hace referencia a entrevistas y registros de clases en audio y video, los cuales no están agregados en este registro

    Notes on the bryophyte flora and vegetation of the central and south-western Balkans.

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    Puglisi, M., Campisi, P., laku.i., D., surina, B., Di Pietro, R., Privitera, M. Notes on the bryophyte flora and vegetation of the central and south-western Balkans. Lazaroa 34: 107-116 (2013). A study on the bryophyte flora and vegetation was carried out in the mountains at the boundary between Albania, Macedonia and Montenegro. The study area included Maja and jezerces massif (Prokletije mts., sE Dinaric Alps) and Mt korab (Šar-Pindos Range) in Macedonia. several records for the bryological flora of Macedonia and Albania are reported. In particular Scapania cuspiduligera and Distichium inclinatum are new records for the Albanian flora. In addition some bryophytic and bryo-chormophytic associations belonging to the phytosociological classes Ctenidietea mollusci and Montio fontanae-Cardaminetea amarae are reported too. © 2013. Universidad Complutense de Madrid

    Electrodynamics of superconducting pnictide superlattices

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    It has been recently reported (S. Lee et al., Nature Materials 12, 392, 2013) that superlattices where layers of the 8% Co-doped BaFe2As2 superconducting pnictide are intercalated with non superconducting ultrathin layers of either SrTiO3 or of oxygen-rich BaFe2As2, can be used to control flux pinning, thereby increasing critical fields and currents, without significantly affecting the critical temperature of the pristine superconducting material. However, little is known about the electron properties of these systems. Here we investigate the electrodynamics of these superconducting pnictide superlattices in the normal and superconducting state by using infrared reflectivity, from THz to visible range. We find that multi-gap structure of these superlattices is preserved, whereas some significant changes are observed in their electronic structure with respect to those of the original pnictide. Our results suggest that possible attempts to further increase the flux pinning may lead to a breakdown of the pnictide superconducting properties.Comment: 4 pages, two figure

    A spatial model of autocatalytic reactions

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    Biological cells with all of their surface structure and complex interior stripped away are essentially vesicles - membranes composed of lipid bilayers which form closed sacs. Vesicles are thought to be relevant as models of primitive protocells, and they could have provided the ideal environment for pre-biotic reactions to occur. In this paper, we investigate the stochastic dynamics of a set of autocatalytic reactions, within a spatially bounded domain, so as to mimic a primordial cell. The discreteness of the constituents of the autocatalytic reactions gives rise to large sustained oscillations, even when the number of constituents is quite large. These oscillations are spatio-temporal in nature, unlike those found in previous studies, which consisted only of temporal oscillations. We speculate that these oscillations may have a role in seeding membrane instabilities which lead to vesicle division. In this way synchronization could be achieved between protocell growth and the reproduction rate of the constituents (the protogenetic material) in simple protocells.Comment: Submitted to Phys. Rev.

    Mutation in a conserved motif next to the insulin receptor key autophosphorylation sites de-regulates kinase activity and impairs insulin action.

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    We have recently reported two non-insulin-dependent diabetic patients exhibiting a heterozygous point mutation (R1152-Q) next to the key tyrosine autophosphorylation sites (Y1146, Y1150, Y1151) of the insulin receptor. In the present study, we demonstrate that the Q1152 mutation alters a previously unrecognized consensus sequence in the insulin receptor family of tyrosine kinases. To define the effect of this alteration on insulin receptor function, the mutant insulin receptor (Q1152) was constructed and overexpressed in NIH-3T3 cells. In spite of normal insulin binding, "in vivo" and "in vitro" autophosphorylation as well as transphosphorylation by the wild-type receptor (WT) were deficient in Q1152 as compared with the transfected WT receptors. Insulin-stimulated kinase activity toward poly(Glu, Tyr) 4:1 and the endogenous substrates p120 and p175 were also impaired in Q1152. However, insulin-independent kinase activity of Q1152 was 2-5-fold higher than that of WT. While insulin stimulated 2-deoxyglucose uptake and glycogen synthase activity in WT-transfected cells with a sensitivity proportional to receptor number, no insulin stimulation was observed in Q1152 cells. Similar to the kinase, insulin-independent glycogen synthase activity and 2-deoxyglucose uptake were 2-fold higher in Q1152 than in either WT or parental cells. We conclude that the Q1152 mutation deregulates insulin receptor kinase and generates insulin insensitivity in cells. Alterations in this highly conserved region of the insulin receptor may contribute to non-insulin dependent diabetes mellitin pathogenesis in humans
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