408 research outputs found

    Molecular constituents of neuronal AMPA receptors

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    Dynamic regulation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) underlies aspects of synaptic plasticity. Although numerous AMPAR-interacting proteins have been identified, their quantitative and relative contributions to native AMPAR complexes remain unclear. Here, we quantitated protein interactions with neuronal AMPARs by immunoprecipitation from brain extracts. We found that stargazin-like transmembrane AMPAR regulatory proteins (TARPs) copurified with neuronal AMPARs, but we found negligible binding to GRIP, PICK1, NSF, or SAP-97. To facilitate purification of neuronal AMPAR complexes, we generated a transgenic mouse expressing an epitope-tagged GluR2 subunit of AMPARs. Taking advantage of this powerful new tool, we isolated two populations of GluR2 containing AMPARs: an immature complex with the endoplasmic reticulum chaperone immunoglobulin-binding protein and a mature complex containing GluR1, TARPs, and PSD-95. These studies establish TARPs as the auxiliary components of neuronal AMPARs

    mRNA concentrations of MIF in subcutaneous abdominal adipose cells are associated with adipocyte size and insulin action

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    Objective To determine whether the mRNA concentrations of inflammation response genes in isolated adipocytes and in cultured preadipocytes are related to adipocyte size and in vivo insulin action in obese individuals. Design Cross-sectional inpatient study. Subjects Obese Pima Indians with normal glucose tolerance. Measurements Adipocyte diameter (by microscope technique; n=29), expression of candidate genes (by quantitative real-time PCR) in freshly isolated adipocytes (monocyte chemoattractant protein [MCP] 1 and MCP2, macrophage inflammatory protein [MIP] 1α, MIP1β and MIP2, macrophage migration inhibitory factor [MIF], tumor necrosis factor alpha, interleukin [IL] 6 and IL8; n=22) and cultured preadipocytes (MCP1, MIP1α, MIF, IL6 and matrix metalloproteinase 2; n=33) from subcutaneous abdominal adipose tissue (by aspiration biopsy, n=34), body fat by dual-energy X-ray absorptiometry, glucose tolerance by 75-gram oral glucose tolerance test, and insulin action by euglycemic-hyperinsulinemic clamp (insulin infusion rate 40 mU/m2.min)(all n=34). Results MIF was the only gene whose expression in both freshly isolated adipocytes and cultured preadipocytes was positively associated with adipocytes diameter and negatively associated with peripheral and hepatic insulin action (all P<0.05). In multivariate analysis, the association between adipocyte MIF mRNA concentrations and adipocytes diameter was independent of percent body fat (P=0.03), whereas adipocyte MIF mRNA concentrations but not adipocytes diameter independently predicted peripheral insulin action. The mRNA expression concentrations of MIF gene in adipocytes were not associated with plasma concentrations of MIF, but were negatively associated with plasma adiponectin concentrations (P=0.004). In multivariate analysis, adipocyte MIF RNA concentrations (P=0.03) but not plasma adiponectin concentrations (P=0.4) remained a significant predictor of insulin action. Conclusions Increased expression of MIF gene in adipose cells may be an important link between obesity characterized by enlarged adipocytes and insulin resistance in normal glucose tolerant people

    The Influence of Emissions from Maritime Transport on Air Quality in the Strait of Gibraltar (Spain)

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    Gaseous and particulate emissions from oceangoing ships have a significant effect on the quality of air in cities. This study estimates mainly the influence of NOx, SOx, and particulate matter (PM2.5) on air quality in the Strait of Gibraltar (Spain) using the authors' own Ship's Energy and Emissions Model (SENEM) and the California Puff air quality model (CALPUFF) in 2017. The Algeciras Bay Industrial Zone recorded the highest levels of pollutants, and the Palmones area was identified as a major hotspot, with mean daily ship-sourced SOx concentrations >215 mu g/m(3), while the highest concentrations of PM10 reached 8.5 mu g/m(3) inside the Strait, and the mean yearly contribution of PM2.5 reached 0.86 mu g/m(3) in the city of Algeciras. The incidence of maritime traffic emissions on the levels of particle emissions, CO, HC, NMVOC, and CO2 reached values of up to 20-25% in all the receivers defined in the study

    The origin of the [C II] emission in the S140 PDRs - new insights from HIFI

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    Using Herschel's HIFI instrument we have observed [C II] along a cut through S140 and high-J transitions of CO and HCO+ at two positions on the cut, corresponding to the externally irradiated ionization front and the embedded massive star forming core IRS1. The HIFI data were combined with available ground-based observations and modeled using the KOSMA-tau model for photon dominated regions. Here we derive the physical conditions in S140 and in particular the origin of [C II] emission around IRS1. We identify three distinct regions of [C II] emission from the cut, one close to the embedded source IRS1, one associated with the ionization front and one further into the cloud. The line emission can be understood in terms of a clumpy model of photon-dominated regions. At the position of IRS1, we identify at least two distinct components contributing to the [C II] emission, one of them a small, hot component, which can possibly be identified with the irradiated outflow walls. This is consistent with the fact that the [C II] peak at IRS1 coincides with shocked H2 emission at the edges of the outflow cavity. We note that previously available observations of IRS1 can be well reproduced by a single-component KOSMA-tau model. Thus it is HIFI's unprecedented spatial and spectral resolution, as well as its sensitivity which has allowed us to uncover an additional hot gas component in the S140 region.Comment: accepted for publication in Astronomy and Astrophysics (HIFI special issue

    Calculating a Drop in Carbon Emissions in the Strait of Gibraltar (Spain) from Domestic Shipping Traffic Caused by the COVID-19 Crisis

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    As a consequence of the COVID-19 pandemic, the Spanish government declared a State of Emergency, and domestic passenger ship traffic was restricted in Spanish ports. This manuscript presents scenarios of emissions from domestic shipping traffic in the seas of the Strait of Gibraltar (Spain) over three months of the COVID-19 pandemic. Emissions were estimated for only 90 days of the pandemic, and two scenarios were studied: emissions while vessels were berthed at the Algeciras Port and emissions as a consequence of the interruption of passenger ship transportation in the Strait of Gibraltar. To this end, the authors' own model was used, which has near zero uncertainties. This model was used for the first time in this study and takes into account both meteorological and sea condition parameters, as well as the efficiency of the propulsion system. The manuscript concentrates on the emissions of greenhouse gases (GHGs), nitrogen oxides (NOx), sulphur oxides (SOx), carbon dioxide (CO2), and particulate matter (PM) from six Ro-Pax ships that ceased to operate. The main finding is that as a consequence of the pandemic, reductions of up to 12% were found in the Strait of Gibraltar in all the pollutants and GHGs when taking into account all international traffic, while the decrease in emissions from domestic traffic only reached 51%

    Calidad del suelo en huertos de cítricos ecológicos

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    El mantenimiento de la fertilidad del suelo contemplada globalmente en los aspectos físicos, químicos y biológicos es un factor clave en el sistema de producción ecológica. De ahí que en este sistema agrario se ponga un particular énfasis en la fertilización orgánica. En este estudio se comparan los resultados de varios indicadores de la calidad del suelo registrados en un grupo de 21 parcelas de cítricos ecológicos y otras tantas convencionales. La fertilidad del suelo en los huertos ecológicos resultó superior a la obtenida en los convencionales. Las actividades enzimáticas (fosfatasa alcalina y deshidrogenasa) se revelaron interesantes indicadores de los cambios a corto plazo de la calidad del suelo. La introducción de prácticas de fertilización ecológica con reducción en las aportaciones de insumos no afectó de forma significativa al estado nutritivo de los huertos de cítricos evaluados mediante análisis foliar. El sistema ecológico tampoco afectó de forma significativa al nivel de micorrización ni a las poblaciones de nematodos y hongos nematófagos
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