33 research outputs found

    Purification, Cloning, Characterization and Essential Amino Acid Residues Analysis of a New iota-Carrageenase from Cellulophaga sp QY3

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    ι-Carrageenases belong to family 82 of glycoside hydrolases that degrade sulfated galactans in the red algae known as ι-carrageenans. The catalytic mechanism and some substrate-binding residues of family GH82 have been studied but the substrate recognition and binding mechanism of this family have not been fully elucidated. We report here the purification, cloning and characterization of a new ι-carrageenase CgiA_Ce from the marine bacterium Cellulophaga sp. QY3. CgiA_Ce was the most thermostable carrageenase described so far. It was most active at 50°C and pH 7.0 and retained more than 70% of the original activity after incubation at 50°C for 1 h at pH 7.0 or at pH 5.0–10.6 for 24 h. CgiA_Ce was an endo-type ι-carrageenase; it cleaved ι-carrageenan yielding neo-ι-carrabiose and neo-ι-carratetraose as the main end products, and neo-ι-carrahexaose was the minimum substrate. Sequence analysis and structure modeling showed that CgiA_Ce is indeed a new member of family GH82. Moreover, sequence analysis of ι-carrageenases revealed that the amino acid residues at subsites −1 and +1 were more conserved than those at other subsites. Site-directed mutagenesis followed by kinetic analysis identified three strictly conserved residues at subsites −1 and +1 of ι-carrageenases, G228, Y229 and R254 in CgiA_Ce, which played important roles for substrate binding. Furthermore, our results suggested that Y229 and R254 in CgiA_Ce interacted specifically with the sulfate groups of the sugar moieties located at subsites −1 and +1, shedding light on the mechanism of ι-carrageenan recognition in the family GH82

    Fluropyrimidine single agent or doublet chemotherapy as second line treatment in advanced biliary tract cancer

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    Fluoropyrimidine (FP) plus platinum chemotherapy has been recently established as a second-line (L2) preferred option in advanced biliary tract cancer (aBTC) (ABC-06 phase III trial). However, the overall survival (OS) benefit was limited and comparison with FP monotherapy was not available. Our aim was to assess the OS of patients treated with a FP monotherapy compared to a doublet with irinotecan or platinum in L2. We performed a retrospective analysis of two large multicenter prospective cohorts: a French cohort (28 centers) and an Italian cohort (9 centers). All consecutive patients with aBTC receiving FP-based L2 after gemcitabine plus cisplatin/gemcitabine plus oxaliplatin L1 between 2003 and 2016 were included. A subgroup analysis according to performance status (PS) and an exploratory analysis according to platinum sensitivity in L1 were planned. In the French cohort (n = 351), no significant OS difference was observed between the FP monotherapy and doublet groups (median OS: 5.6 vs 6.8 months, P =.65). Stratification on Eastern Cooperative Oncology Group (ECOG) PS showed similar results in PS 0-1 and 2. Median OS was not different between FP monotherapy, platinum- and irinotecan-based doublets (5.6 vs 7.1 vs 6.7 months, P =.68). Similar findings were observed in the Italian cohort (n = 174) and in the sensitivity analysis in pooled cohorts (n = 525). No L2 regimen seemed superior over others in the platinum resistant/refractory or sensitive subgroups. Our results suggest that FP monotherapy is as active as FP doublets in aBTC in L2, regardless of the patient PS and country, and could be a therapeutic option in this setting

    The eEF1γ Subunit Contacts RNA Polymerase II and Binds Vimentin Promoter Region

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    Here, we show that the eukaryotic translation elongation factor 1 gamma (eEF1γ) physically interacts with the RNA polymerase II (pol II) core subunit 3 (RPB3), both in isolation and in the context of the holo-enzyme. Importantly, eEF1γ has been recently shown to bind Vimentin mRNA. By chromatin immunoprecipitation experiments, we demonstrate, for the first time, that eEF1γ is also physically present on the genomic locus corresponding to the promoter region of human Vimentin gene. The eEF1γ depletion causes the Vimentin protein to be incorrectly compartmentalised and to severely compromise cellular shape and mitochondria localisation. We demonstrate that eEF1γ partially colocalises with the mitochondrial marker Tom20 and that eEF1γ depletion increases mitochondrial superoxide generation as well as the total levels of carbonylated proteins. Finally, we hypothesise that eEF1γ, in addition to its role in translation elongation complex, is involved in regulating Vimentin gene by contacting both pol II and the Vimentin promoter region and then shuttling/nursing the Vimentin mRNA from its gene locus to its appropriate cellular compartment for translation

    Toll-Like Receptor 3 (TLR3) Plays a Major Role in the Formation of Rabies Virus Negri Bodies

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    Human neurons express the innate immune response receptor, Toll-like receptor 3 (TLR3). TLR3 levels are increased in pathological conditions such as brain virus infection. Here, we further investigated the production, cellular localisation, and function of neuronal TLR3 during neuronotropic rabies virus (RABV) infection in human neuronal cells. Following RABV infection, TLR3 is not only present in endosomes, as observed in the absence of infection, but also in detergent-resistant perinuclear inclusion bodies. As well as TLR3, these inclusion bodies contain the viral genome and viral proteins (N and P, but not G). The size and composition of inclusion bodies and the absence of a surrounding membrane, as shown by electron microscopy, suggest they correspond to the previously described Negri Bodies (NBs). NBs are not formed in the absence of TLR3, and TLR3−/− mice—in which brain tissue was less severely infected—had a better survival rate than WT mice. These observations demonstrate that TLR3 is a major molecule involved in the spatial arrangement of RABV–induced NBs and viral replication. This study shows how viruses can exploit cellular proteins and compartmentalisation for their own benefit

    The Performance of Characteristics-based Indices-super-1

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    "This paper analyses a set of characteristics-based indices that, it has been argued, outperform market cap-weighted indices. We analyse the performance of an exhaustive list of these indices and show that i) the outperformance over value-weighted indices may be negative over long time periods, and ii) there is no significant outperformance over equal-weighted indices. An analysis of the style and sector exposures of characteristics-based indices reveals a significant value tilt. When this tilt is properly adjusted for, the abnormal returns of these indices decrease considerably. Moreover, it is straightforward to construct portfolios with higher Sharpe ratios than characteristics-based indices through factor or sector tilts." Copyright (c) 2008 The Authors Journal compilation (c) 2008 Blackwell Publishing Ltd.

    Absence of deficits in social behaviors and ultrasonic vocalizations in later generations of mice lacking neuroligin4.

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    International audienceMutations in NLGN4X have been identified in individuals with autism spectrum disorders and other neurodevelopmental disorders. A previous study reported that adult male mice lacking neuroligin4 (Nlgn4) displayed social approach deficits in the three-chambered test, altered aggressive behaviors and reduced ultrasonic vocalizations. To replicate and extend these findings, independent comprehensive analyses of autism-relevant behavioral phenotypes were conducted in later generations of the same line of Nlgn4 mutant mice at the National Institute of Mental Health in Bethesda, MD, USA and at the Institut Pasteur in Paris, France. Adult social approach was normal in all three genotypes of Nlgn4 mice tested at both sites. Reciprocal social interactions in juveniles were similarly normal across genotypes. No genotype differences were detected in ultrasonic vocalizations in pups separated from the nest or in adults during reciprocal social interactions. Anxiety-like behaviors, self-grooming, rotarod and open field exploration did not differ across genotypes, and measures of developmental milestones and general health were normal. Our findings indicate an absence of autism-relevant behavioral phenotypes in subsequent generations of Nlgn4 mice tested at two locations. Testing environment and methods differed from the original study in some aspects, although the presence of normal sociability was seen in all genotypes when methods taken from Jamain et al. (2008) were used. The divergent results obtained from this study indicate that phenotypes may not be replicable across breeding generations, and highlight the significant roles of environmental, generational and/or procedural factors on behavioral phenotypes

    Hedge fund transparency: where do we stand?

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    Unlike mutual funds, hedge funds are reluctant to provide detailed information on their investment portfolios. Since hedge funds may use niche investment strategies in narrow market segments, fund managers portend that thorough disclosure of their portfolio holdings—which are important to assessing future returns—would crowd out their trades, thus decreasing opportunities to generate outsized returns. However, incomplete disclosure can have some undesirable side effects. It might encourage hedge fund managers to take positions that are riskier than provided for by the manager’s mandate. Investors even risk fraudulent behavior, since the action of hedge fund management may be detected only when a fund has failed.This article presents the results of a comprehensive survey of hedge fund managers and investors on current hedge fund reporting practices. The authors find that the quality of hedge fund reporting is considered an important investment criterion. In analyzing the spectrum of opinions, the authors identify critical points of conflict between investors and managers.They find that investors are especially dissatisfied with the quality of information on liquidity and operational risk exposure. The survey also reveals that inappropriate performance measures are prevalent

    Selective internal radiation combined with chemotherapy maintains the quality of life in intrahepatic cholangiocarcinomas

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    International audienceBackground: In the Yttrium-90 Microspheres in Cholangiocarcinoma (MISPHEC) single-arm phase 2 trial, concomitant chemotherapy and selective internal radiotherapy (SIRT) showed antitumor activity as a first-line treatment of unresectable intrahepatic cholangiocarcinomas (ICCs). In this sub-analysis, we aimed to evaluate one of the secondary endpoints, the health-related quality of life (QoL), evaluated with an EORTC QLQ-C30 instrument at the baseline and during treatment. Methods: The MISPHEC trial included treatment-naïve patients with an unresectable ICC between November 2013 and June 2016. Patients received concomitant first-line chemotherapy with cisplatin and gemcitabine for 8 cycles; SIRT was administered during cycle 1 (for patients with unilobar dis-ease) or cycles 1 and 3 (for patients with bilobar disease) using glass Yttrium-90 microspheres. We evaluated the QoL—measured by the QLQ-C30 questionnaire—at the baseline, every 8 weeks during chemotherapy and follow-up, between 12 and 15 weeks after embolization and every 12 weeks after a liver resection if applicable. Results: A total of 41 patients were included, of which 34 com-pleted questionnaires at the baseline. No clinically significant changes in the global health score or the sub-scales of the QLQ-C30 were observed during follow-up. The physical, social and role function mean score worsened during treatment and fatigue, nausea and pain scores increased although the differences were not clinically significant. In patients undergoing subsequent surgery, the QoL was not impaired. Conclusions: A combination of SIRT and chemotherapy with gemcitabine and cisplatin as the first-line treatment of unresectable ICCs was found to maintain the QoL. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
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