119 research outputs found

    A Search for Novel Legionella pneumophila Effector Proteins Reveals a Strain Specific Nucleotropic Effector

    Get PDF
    Legionella pneumophila is an accidental human pathogen that causes the potentially fatal Legionnaires' disease, a severe type of pneumonia. The main virulence mechanism of L. pneumophila is a Type 4B Secretion System (T4SS) named Icm/Dot that transports effector proteins into the host cell cytosol. The concerted action of effectors on several host cell processes leads to the formation of an intracellular Legionella-containing vacuole that is replication competent and avoids phagolysosomal degradation. To date over 300 Icm/Dot substrates have been identified. In this study, we searched the genome of a L. pneumophila strain (Pt/VFX2014) responsible for the second largest L. pneumophila outbreak worldwide (in Vila Franca de Xira, Portugal, in 2014) for genes encoding potential novel Icm/Dot substrates. This strain Pt/VFX2014 belongs to serogroup 1 but phylogenetically segregates from all other serogroup 1 strains previously sequenced, displaying a unique mosaic genetic backbone. The ability of the selected putative effectors to be delivered into host cells by the T4SS was confirmed using the TEM-1 β-lactamase reporter assay. Two previously unknown Icm/Dot effectors were identified, VFX05045 and VFX10045, whose homologs Lpp1450 and Lpp3070 in clinical strain L. pneumophila Paris were also confirmed as T4SS substrates. After delivery into the host cell cytosol, homologs VFX05045/Lpp1450 remained diffused in the cell, similarly to Lpp3070. In contrast, VFX10045 localized to the host cell nucleus. To understand how VFX10045 and Lpp3070 (94% of identity at amino acid level) are directed to distinct sites, we carried out a comprehensive site-directed mutagenesis followed by analyses of the subcellular localization of the mutant proteins. This led to the delineation of region in the C-terminal part (residues 380 to 534) of the 583 amino acid-long VFX10045 as necessary and sufficient for nuclear targeting and highlighted the fundamental function of the VFX10045-specific R440 and I441 residues in this process. These studies revealed a strain-specific nucleotropism for new effector VFX10045/Lpp3070, which anticipates distinct functions between these homologs.This project has been funded by: Research Grant 2016 by the European Society of Clinical Microbiology and lnfectious Diseases (ESCMID) to IF; by National funds from FCT - Fundação para a Ciência e a Tecnologia, I.P., in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences - UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy - i4HB.info:eu-repo/semantics/publishedVersio

    PVA-Based Hydrogels Loaded with Diclofenac for Cartilage Replacement

    Get PDF
    Polyvinyl alcohol (PVA) hydrogels have been widely studied for cartilage replacement due to their biocompatibility, chemical stability, and ability to be modified such that they approximate natural tissue behavior. Additionally, they may also be used with advantages as local drug delivery systems. However, their properties are not yet the most adequate for such applications. This work aimed to develop new PVA-based hydrogels for this purpose, displaying improved tribomechani- cal properties with the ability to control the release of diclofenac (DFN). Four types of PVA-based hydrogels were prepared via freeze-thawing: PVA, PVA/PAA (by polyacrylic acid (PAA) addition), PVA/PAA+PEG (by polyethylene glycol (PEG) immersion), and PVA/PAA+PEG+A (by annealing). Their morphology, water uptake, mechanical and rheological properties, wettability, friction coef- ficient, and drug release behavior were accessed. The irritability of the best-performing material was investigated. The results showed that the PAA addition increased the swelling and drug release amount. PEG immersion led to a more compact structure and significantly improved the material’s tribomechanical performance. The annealing treatment led to the material with the most suitable properties: besides presenting a low friction coefficient, it further enhanced the mechanical properties and ensured a controlled DFN release for at least 3 days. Moreover, it did not reveal irritability potential for biological tissues.info:eu-repo/semantics/publishedVersio

    Setting performance indicators for coastal marine protected areas: An expert-based methodology

    Get PDF
    Marine Protected Areas (MPAs) require effective indicators to assess their performance, in compliance with the goals of relevant national and international commitments. Achieving and prioritizing shortlists of multidisciplinary indicators demands a significant effort from specialists to depict the multiple conservation and socioeconomic interests, and the large complexity of natural systems. The present paper describes a structured expert-based methodology (process and outputs) to co-define a list of multidisciplinary MPA performance indicators. This work was promoted by the management authority of coastal MPAs in mainland Portugal to gather a consensual and feasible list of indicators that would guide the design of a future national monitoring program. Hence, Portuguese coastal MPAs served as a case study to develop such a process between 2019 and 2020. In the end, participants (1) agreed on a shortlist of prioritized indicators (i.e., environmental, governance, and socioeconomic indicators) and (2) defined minimum monitoring frequencies for the indicators in this list, compatible with the potential replicability of the associated survey methods. The present approach recommends that management plans incorporate monitoring procedures and survey methods, with a validated list of indicators and associated monitoring periodicity, agreed among researchers, MPA managers and governance experts. The proposed methodology, and the lessons learned from it, can support future processes aiming to define and prioritize MPA performance indicatorsFundação para a Ciência e Tecnologia - FCT, European Maritime and Fisheries Fund (EMFF)info:eu-repo/semantics/publishedVersio

    Psychometric properties of the measure of achieved capabilities in homeless services

    Get PDF
    Background Purposeful participation in personally meaningful life tasks, enjoyment of positive reciprocal relationships, and opportunities to realize one’s potential are growth-related aspects of a meaningful life that should be considered important dimensions of recovery from homelessness. The extent to which homeless services support individuals to achieve the capabilities they need to become who they want to be and do what they want to do is, in turn, an important indicator of their efectiveness. In this study, we developed a measure of achieved capabilities (MACHS) for use in homeless services settings, and assessed its construct and concurrent validity. Methods We analysed data collected from homeless services users at two time points in eight European countries to assess the factor structure and psychometric properties of the new measure. Participants were adults engaged with either Housing First (n=245) or treatment as usual (n=320). Results Exploratory and confrmatory factor analyses yielded a four-factor structure of the capabilities measure: community integration, optimism, safety, and self-determination. We obtained evidence for construct validity through observed correlations between achieved capabilities and recovery, working alliance and satisfaction with services. Moreover, we obtained evidence of the measure’s concurrent validity from its positive association between HF and personal recovery, which was fully mediated by achieved capabilities. Conclusions Findings demonstrate that the MACHS is a valid and reliable measure that may be used to assess the extent to which homeless services support their clients to develop capabilities needed for growth-related recovery. Implications for practice and future research directions are discussed.info:eu-repo/semantics/publishedVersio

    Psychometric properties of the measure of achieved capabilities in homeless services

    Get PDF
    Background Purposeful participation in personally meaningful life tasks, enjoyment of positive reciprocal relationships, and opportunities to realize one’s potential are growth-related aspects of a meaningful life that should be considered important dimensions of recovery from homelessness. The extent to which homeless services support individuals to achieve the capabilities they need to become who they want to be and do what they want to do is, in turn, an important indicator of their efectiveness. In this study, we developed a measure of achieved capabilities (MACHS) for use in homeless services settings, and assessed its construct and concurrent validity. Methods We analysed data collected from homeless services users at two time points in eight European countries to assess the factor structure and psychometric properties of the new measure. Participants were adults engaged with either Housing First (n=245) or treatment as usual (n=320). Results Exploratory and confrmatory factor analyses yielded a four-factor structure of the capabilities measure: community integration, optimism, safety, and self-determination. We obtained evidence for construct validity through observed correlations between achieved capabilities and recovery, working alliance and satisfaction with services. Moreover, we obtained evidence of the measure’s concurrent validity from its positive association between HF and personal recovery, which was fully mediated by achieved capabilities. Conclusions Findings demonstrate that the MACHS is a valid and reliable measure that may be used to assess the extent to which homeless services support their clients to develop capabilities needed for growth-related recovery. Implications for practice and future research directions are discussed.Horizon2020 of the European Commissioninfo:eu-repo/semantics/publishedVersio
    • …
    corecore