838 research outputs found

    Multistep, sequential control of the trafficking and function of the multiple sulfatase deficiency gene product, SUMF1 by PDI, ERGIC-53 and ERp44.

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    Sulfatase modifying factor 1 (SUMF1) encodes for the formylglicine generating enzyme, which activates sulfatases by modifying a key cysteine residue within their catalytic domains. SUMF1 is mutated in patients affected by multiple sulfatase deficiency, a rare recessive disorder in which all sulfatase activities are impaired. Despite the absence of canonical retention/retrieval signals, SUMF1 is largely retained in the endoplasmic reticulum (ER), where it exerts its enzymatic activity on nascent sulfatases. Part of SUMF1 is secreted and paracrinally taken up by distant cells. Here we show that SUMF1 interacts with protein disulfide isomerase (PDI) and ERp44, two thioredoxin family members residing in the early secretory pathway, and with ERGIC-53, a lectin that shuttles between the ER and the Golgi. Functional assays reveal that these interactions are crucial for controlling SUMF1 traffic and function. PDI couples SUMF1 retention and activation in the ER. ERGIC-53 and ERp44 act downstream, favoring SUMF1 export from and retrieval to the ER, respectively. Silencing ERGIC-53 causes proteasomal degradation of SUMF1, while down-regulating ERp44 promotes its secretion. When over-expressed, each of three interactors favors intracellular accumulation. Our results reveal a multistep control of SUMF1 trafficking, with sequential interactions dynamically determining ER localization, activity and secretion

    Oxygen Consumption in South African Sauvignon Blanc Wines: Role of Glutathione, Sulphur Dioxide and Certain Phenolics

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    The aim of this research was to investigate the interaction between sulphur dioxide, glutathione (GSH) andcertain phenols in the presence of oxygen in a synthetic wine and in clarified Sauvignon blanc wine. In thisstudy, the clarified wine, from which most of the phenols had been removed, was compared to syntheticwine solution, with both mediums being enriched with caffeic acid to investigate the effect of different levelsof sulphur dioxide and GSH on oxygen consumption. Moreover, thirteen young South African Sauvignonblanc wines with different levels of sulphur dioxide were oxygenated, and the oxygen consumption andphenolic and colour changes were monitored over time. The results show that oxygen consumption wasinfluenced greatly by the presence of sulphur dioxide and, to a lesser extent, by the presence of GSH,with both compounds decreasing during the course of the experiment. During oxidation, an increasewas observed in glutathionyl caffeic acid, as well as in oxidised glutathione (GSSG); however, this didnot coincide with the percentage decrease in GSH. Oxidation further led to an increase in absorbancemeasurements at 420 and 440 nm (yellow-orange colour), which were reduced by the presence of SO2. Alarge variation was also observed in the oxygen consumption of the young wines, with this rate increasingwith an increase in SO2 concentration. Positive correlations were also observed between oxygen, SO2, GSHand Cu concentrations, which were again negatively correlated with absorbance at 420 and 440 nm andGSSG concentrations

    Oxygen Consumption in South African Sauvignon Blanc Wines: Role of Glutathione, Sulphur Dioxide and Certain Phenolics

    Get PDF
    The aim of this research was to investigate the interaction between sulphur dioxide, glutathione (GSH) and certain phenols in the presence of oxygen in a synthetic wine and in clarified Sauvignon blanc wine. In this study, the clarified wine, from which most of the phenols had been removed, was compared to synthetic wine solution, with both mediums being enriched with caffeic acid to investigate the effect of different levels of sulphur dioxide and GSH on oxygen consumption. Moreover, thirteen young South African Sauvignon blanc wines with different levels of sulphur dioxide were oxygenated, and the oxygen consumption and phenolic and colour changes were monitored over time. The results show that oxygen consumption was influenced greatly by the presence of sulphur dioxide and, to a lesser extent, by the presence of GSH, with both compounds decreasing during the course of the experiment. During oxidation, an increase was observed in glutathionyl caffeic acid, as well as in oxidised glutathione (GSSG); however, this did not coincide with the percentage decrease in GSH. Oxidation further led to an increase in absorbance measurements at 420 and 440 nm (yellow-orange colour), which were reduced by the presence of SO2. A large variation was also observed in the oxygen consumption of the young wines, with this rate increasing with an increase in SO2 concentration. Positive correlations were also observed between oxygen, SO2, GSH and Cu concentrations, which were again negatively correlated with absorbance at 420 and 440 nm and GSSG concentrations

    Avaliação da ameaça de erosão hídrica na ilha da Madeira - Portugal

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    Na estimativa da erosão hídrica na ilha da Madeira aplicou-se a Equação de Wischmeier. Recorreu-se a relações para estimar a erosividade (R); foi adequado o Índice Modificado de Fournier e relação IMF/R. cartografada a erosividade os restantes parâmetros resultaram da metodologia. IMF varia entre 81.0–465.0 mm. A equação R = 1.365 IMF1.408 estima a erosividade anual precipitação, com dados de Funchal-Observatório, sul de Portugal e valores da literatura, obtendo-se R ≈ 2 964 MJ mm h−1 ha−1 ano−1, variando entre 660- 8515. Erosão média é 28 t ha−1 ano−1, excedendo 100 em >4.9% da área. A ameaça de erosão adveio da divisão do volume de solo dos horizontes mobilizáveis, pela erosão anual. O resultado -número de anos- que ocorre a perda do solo de cobertura. Apesar do tempo para esgotamento do solo, ser >20 000 anos, a ameaça de erosão, alta e muito alta, é relevante. Estas ameaças (depleção <100 anos) ocorrem em 263 km2 (35.6%); na ameaça muito alta (depleção em <10 anos) a área é ≈40 km2 (5.4%). Encostas com declives muito elevados estão associadas a ameaças altas (ou muito altas). Efetuouse a análise da precipitação 20 de Fevereiro, obtendo-se um período de retorno superior a 100 anos.info:eu-repo/semantics/publishedVersio

    Probing the in-plane electron spin polarization in Ge/Si0.15 Ge0.85 multiple quantum wells

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    We investigate spin transport in a set of Ge/Si0.15Ge0.85 multiple quantum wells (MQWs) as a function of the well thickness. We exploit optical orientation to photogenerate spin-polarized electrons in the discrete energy levels of the well conduction band at the Γ point of the Brillouin zone. After diffusion, we detect the optically oriented spins by means of the inverse spin-Hall effect (ISHE) taking place in a thin Pt layer grown on top of the heterostructure. The employed spin injection/detection scheme is sensitive to in-plane spin-polarized electrons, therefore, by detecting the ISHE signal as a function of the photon energy, we evaluate the spin polarization generated by optical transitions driven by the component of the light wave vector in the plane of the wells. In this way, we also gain insight into the electron spin-diffusion length in the MQWs. The sensitivity of the technique to in-plane spin-related properties is a powerful tool for the investigation of the in-plane component of the spin polarization in MQWs, which is otherwise commonly inaccessible

    Surface Phase Transitions Induced by Electron Mediated Adatom-Adatom Interaction

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    We propose that the indirect adatom-adatom interaction mediated by the conduction electrons of a metallic surface is responsible for the 3×33×3\sqrt{3}\times \sqrt{3}\Leftrightarrow 3\times 3 structural phase transitions observed in Sn/Ge (111) and Pb/Ge (111). When the indirect interaction overwhelms the local stress field imposed by the substrate registry, the system suffers a phonon instability, resulting in a structural phase transition in the adlayer. Our theory is capable of explaining all the salient features of the 3×33×3\sqrt{3}\times \sqrt{3}\Leftrightarrow 3\times 3 transitions observed in Sn/Ge (111) and Pb/Ge (111), and is in principle applicable to a wide class of systems whose surfaces are metallic before the transition.Comment: 4 pages, 5 figure

    No COVID-19 pandemic impact on incidence and clinical presentation of celiac disease in Italian children

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    Aim: We aimed to evaluate the impact of Coronavirus Disease-19 (COVID-19) pandemic on the incidence and clinical presentation of celiac disease (CD) in children.MethodsThe diagnoses of CD were compared between the COVID-19 pandemic (from April 2020 to March 2022) and the pre-pandemic period (from April 2018 to March 2020) in three Italian Paediatric Gastroenterology centres (Varese, Como, Catanzaro). Electronic patient records were reviewed and additional information were collected through parental interview. The diagnosis of CD was made according to ESPGHAN criteria. SARS-CoV-2 infection was diagnosed based on pre-vaccination positive serum antibodies or nasopharyngeal swabs. Z test and chi-square were used for statistical analysis.ResultsThe overall number of paediatric diagnosis of CD did not differ between the two years pre-pandemic and pandemic periods (177 and 172 cases) in the three Italian participating centres. Clinical presentation of CD was also similar throughout the study periods. SARS-CoV-2 infection has been documented in 10.6% of children but only in 5.8% of these occurred before CD diagnosis.ConclusionDifferent to what reported for other autoimmune diseases, the incidence and presenting symptoms of CD in our paediatric population did not change during the COVID-19 pandemic compared to the previous 2 years
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