1,355,414 research outputs found
Pontin, A, 181607
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/411188Surname: PONTIN. Given Name(s) or Initials: A. Military Service Number or Last Known Location: 181607. Missing, Wounded and Prisoner of War Enquiry Card Index Number: S11299.226901
Item: [2016.0049.43454] "Pontin, A, 181607
Sul monitoraggio in continuo delle portate in torrenti e sorgenti alpini-Il Torrente Mis
No full textWater diversion for irrigation and power supply causes an effective decreasing of environmental flows in alpine area, with negative effects on the river ecosystem. As a consequence it’s worthwhile to assess environmental flow for the proper management of water diversion. This type of assessment is generally performed by hydrologic methods taking into account duration curves or morphological features of the watersheds or by naturalistic parameters. Another method is to directly measure creeks and springs water discharge in order to construct a continuous watershed outflow hydrogram. The study area is located in the Belluno Dolomites National Park (Veneto Region, Northern Italy). Mis watershed is taken into account; this stream is affected by hydraulic diversion for hydroelectric power. The upper reach of the watershed is fully located inside a protected area; from an hydrogeologic stand-point dominant groundwater flow is of a karst type with few important springs contributing to the major percentage of creeks base flow. We have installed a monitoring system based upon total amount of 2 continuous stream stage monitoring devices and 1 in the main spring. The paper deals with the description of the applied methodology and the first results of the monitoring
Pontin is essential for murine hematopoietic stem cell survival
No full textPontin is a highly conserved DNA helicase/ATPase which is a component of several macromolecular complexes with functions that include DNA repair, telomere maintenance and tumor suppression. While Pontin is known to be essential in yeast, fruit flies and frogs, its physiological role in mammalian organisms remains to be determined. We here find that Pontin is highly expressed in embryonic stem cells and hematopoietic tissues. Through germline inactivation of Ruvbl1, the gene encoding Pontin, we found it to be essential for early embryogenesis, as Ruvbl1 null embryos could not be recovered beyond the blastocyst stage where proliferation of the pluripotent inner cell mass was impaired. Conditional ablation of Ruvbl1 in hematopoietic tissues led to bone marrow failure. Competitive repopulation experiments showed that this included the loss of hematopoietic stem cells through apopotosis. Pontin is, therefore, essential for the function of both embryonic pluripotent cells and adult hematopoietic stem cells
Sustainable use of groundwater resources in Alpine wetlands: multi-depth hydraulic head monitoring relationship to direct recharge and spring exploitation
No full textPeatlands in the Alps are fragile ecosystems of high environmental values and vulnerable to potentially adverse impacts due to groundwater exploitation. This is the case of 2 peatland systems located in the Eastern Alps (Veneto, Northern Italy). The paper deals with the description of the experimental set-up and preliminary results of a hydrological continuous multi-depth piezometers based monitoring system to reconstruct either the hydraulic head field internal to the peatlands or the natural discharge of the exploited aquifers in the surroundings
Current sheets at three-dimensional magnetic nulls:effect of compressibility
No full textThe nature of current sheet formation in the vicinity of three-dimensional (3D) magnetic null points is investigated. The particular focus is upon the effect of the compressibility of the plasma on the qualitative and quantitative properties of the current sheet. An initially potential 3D null is subjected to shearing perturbations, as in a previous paper [Pontin et al., Phys. Plasmas 14, 052106 (2007)] . It is found that as the incompressible limit is approached, the collapse of the null point is suppressed and an approximately planar current sheet aligned to the fan plane is present instead. This is the case regardless of whether the spine or fan of the null is sheared. Both the peak current and peak reconnection rate are reduced. The results have a bearing on previous analytical solutions for steady-state reconnection in incompressible plasmas, implying that fan current sheet solutions are dynamically accessible, while spine current sheet solutions are not
Hypoxia-induced methylation of a pontin chromatin remodeling factor
No full textPontin is a chromatin remodeling factor that possesses both ATPase and DNA helicase activities. Although Pontin is frequently overexpressed in human cancers of various types and implicated in oncogenic functions, the upstream signaling network leading to the regulation of Pontin that in turn affects transcription of downstream target genes has not been extensively studied. Here, we identify Pontin is methylated by G9a/GLP methyltransferases in hypoxic condition and potentiates HIF-1α-mediated activation by increasing the recruitment of p300 coactivator to a subset of HIF-1α target promoters. Intriguingly, Pontin methylation results in the increased invasive and migratory properties by activating downstream target gene, Ets1. In contrast, inhibition of Pontin methylation results in the suppression of tumorigenic and metastatic properties. Together, our data provide new approaches by targeting Pontin methylation and its downstream targets for the development of therapeutic agents for human cancers
Bases moléculaires des interactions Pontin-, Reptin-Nucléosome
No full textLes hélicases ATP-dépendantes Pontin et Reptin sont nécessaires aux activités de nombreux complexes protéiques, en particulier des complexes de remodelage de la chromatine ou des assemblages de facteurs de transcription. Néanmoins, aucun lien n'a encore été défini entre les propriétés biochimiques des protéines Pontin et Reptin et leurs fonctions in vivo. Nous avons étudié l'impact de l'unité de base de la chromatine, le nucléosome, sur les activités biochimiques des protéines Pontin et Reptin. Un pré-requis pour cette étude a été la purification des protéines Pontin et Reptin, sous leur forme monomérique ou hexamérique, et des histones, corps protéiques des nucléosomes. Il a également été nécessaire d'optimiser la reconstitution in vitro de mononucléosomes. Avec ces outils, nous avons identifié un effet fonctionnel des nucléosomes sur l'activité des protéines Pontin et Reptin qui vient compléter une interaction physique entre Pontin ou Reptin et les nucléosomes. Les protéines Pontin et Reptin forment un complexe stable avec des mononucléosomes lequel dépend de la région N-terminale de l'histone H3. Nous montrons que l'activité ATPase ADN-dépendante des protéines Pontin et Reptin est modulée différemment par l'extrémité N-terminale d'H3 suivant qu'elle porte ou non des modifications post-traductionnelles. Corrélé à cela, ces mêmes extrémités N-terminales d'H3 régulent l'état d'oligomérisation des protéines Pontin et Reptin. De plus, le profil des protéines co-immunoprecipitées avec les monomères de Pontin ou Reptin diffère de celui obtenu avec les formes hexamériques. Nous proposons que les protéines Pontin et Reptin constituent une plateforme moléculaire de recrutement pour des facteurs protéiques, et, au-delà, coordonnent ce recrutement des différents partenaires par des changements de leurs états oligomériques eux-mêmes régulés par leur interaction avec la région N-terminale de l'histone H3.The Pontin and Reptin DNA-dependent ATPases are both necessary for activity of numerous cellular complexes, in particular chromatin remodeling complexes or transcription factor assemblies. However, no link has yet been defined between the biochemical properties of Pontin and Reptin and these in vivo functions. We have studied the impact of the chromatin base unit, the nucleosome, on the biochemical activities Pontin and Reptin. A prerequisite for this was the purification of Pontin and Reptin proteins either as monomers or in hexameric form, and of histones, the protein cores of nucleosomes. It was also necessary to optimize mononucleosome reconstitution in vitro. With these tools, we identified a functional effect of the nucleosome on Pontin and Reptin activity which complemented its physical interaction with nucleosomes. Pontin or Reptin proteins form a stable complex with mononucleosomes which depends on the N-terminal region of histone H3. We show that the Pontin and Reptin DNA-dependent ATPase activity is modulated differentially by the N-terminus tail of H3 and that this depends on whether or not the tail carries post-translational modifications. Correlated with this, the H3 N-terminus also regulates Pontin and Reptin oligomerization. Moreover the profile of proteins which co-immunoprecipitate with Pontin or Reptin monomers is different to that found with the hexameric forms. We propose that Pontin and Reptin proteins could constitute a molecular platform for loading interacting proteins. And furthermore that Pontin and Reptin coordinates recruitment of different proteins by changes in its oligomerisation state in turn regulated by its interaction with the N-terminal region of histone H3
Hypoxia-induced methylation of a pontin chromatin remodeling factor
No full textPontin is a chromatin remodeling factor that possesses both ATPase and DNA helicase activities. Although Pontin is frequently overexpressed in human cancers of various types and implicated in oncogenic functions, the upstream signaling network leading to the regulation of Pontin that in turn affects transcription of downstream target genes has not been extensively studied. Here, we identify Pontin is methylated by G9a/GLP methyltransferases in hypoxic condition and potentiates HIF-1 alpha-mediated activation by increasing the recruitment of p300 coactivator to a subset of HIF-1 alpha target promoters. Intriguingly, Pontin methylation results in the increased invasive and migratory properties by activating downstream target gene, Ets1. In contrast, inhibition of Pontin methylation results in the suppression of tumorigenic and metastatic properties. Together, our data provide new approaches by targeting Pontin methylation and its downstream targets for the development of therapeutic agents for human cancers.open114344sciescopu
Detection of weak stochastic forces in a parametrically stabilized micro-optomechanical system
No full textMeasuring a weak force is an important task for micromechanical systems, both when using devices as sensitive detectors and, particularly, in experiments of quantum mechanics. The optimal strategy for resolving a weak stochastic signal force on a huge background (typically given by thermal noise) is a crucial and debated topic, and the stability of the mechanical resonance is a further, related critical issue. We introduce and analyze the parametric control of the optical spring, which allows us to stabilize the resonance and provides a phase reference for the oscillator motion, yet conserving a free evolution in one quadrature of the phase space. We also study quantitatively the characteristics of our micro-optomechanical system as detector of stochastic force for short measurement times (for quick, high-resolution monitoring) as well as for the longer-term observations that optimize the sensitivity. We compare a simple strategy based on the evaluation of the variance of the displacement which is a widely used technique) with an optimal Wiener-Kolmogorov data analysis. We show that, due to the parametric stabilization of the effective susceptibility, we can more efficiently implement Wiener filtering, and we investigate how this strategy improves the performance of our system. We finally demonstrate the possibility to resolve stochastic force variations well below 1% of the thermal noise.MicroelectronicsElectrical Engineering, Mathematics and Computer Scienc
Pontin, R W, VX62247
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/411189Surname: PONTIN. Given Name(s) or Initials: R W. Military Service Number or Last Known Location: VX62247. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 38161.226902
Item: [2016.0049.43455] "Pontin, R W, VX62247
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