28 research outputs found

    Antimicrobial activity of prophage endolysins against critical Enterobacteriaceae antibiotic-resistant bacteria

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    Enterobacteriaceae species are part of the 2017 World Health Organization antibiotic-resistant priority pathogens list for development of novel medicines. Multidrug-resistant Klebsiella pneumoniae is an increasing threat to public health and has become a relevant human pathogen involved in life-threatening infections. Phage therapy involves the use of phages or their lytic endolysins as bioagents for the treatment of bacterial infectious diseases. Gram-negative bacteria have an outer membrane, making difficult the access of endolysins to the peptidoglycan. Here, three endolysins from prophages infecting three distinct Enterobacterales species, Kp2948-Lys from K. pneumoniae, Ps3418-Lys from Providencia stuartii, and Kaer26608-Lys from Klebsiella aerogenes, were purified and exhibited antibacterial activity against their specific bacterium species verified by zymogram assays. These three endolysins were successfully associated to liposomes composed of dimyristoyl phosphatidyl choline (DMPC), dioleoyl phosphatidyl ethanolamine (DOPE) and cholesteryl hemisuccinate (CHEMS) at a molar ratio (4:4:2), with an encapsulation efficiency ranging from 24 to 27%. Endolysins encapsulated in liposomes resulted in higher antibacterial activity compared to the respective endolysin in the free form, suggesting that the liposome-mediated delivery system enhances fusion with outer membrane and delivery of endolysins to the target peptidoglycan. Obtained results suggest that Kp2948-Lys appears to be specific for K. pneumoniae, while Ps3418-Lys and Kaer26608-Lys appear to have a broader antibacterial spectrum. Endolysins incorporated in liposomes constitute a promising weapon, applicable in the several dimensions (human, animals and environment) of the One Health approach, against multidrug-resistant Enterobacteriaceae.F.F.V. was funded by Fundação para a Ciência e a Tecnologia (FCT) through a project grant (PTDC/BTM-SAL/28978/2017) that supported this work. The work is partially supported by National funds from FCT, projects UIDB/04138/2020, UIDP/04138/2020, UIDB/00211/2020 and UIDB/04046/2020 (DOI https://doi.org/10.54499/UIDB/0404 6/2020)info:eu-repo/semantics/publishedVersio

    Biopolymer-based membranes associated with osteogenic growth peptide for guided bone regeneration

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    Barrier membranes for guided bone regeneration (GBR) mainly promote mechanical maintenance of bone defect space and induce osteopromotion. Additionally, biopolymer-based membranes may provide greater bioactivity and biocompatibility due to their similarity to extracellular matrix (ECM).In this study, biopolymers-based membranes from bacterial cellulose (BC) and collagen (COL) associated with osteogenic growth peptide (OGP(10–14)) were evaluated to determine in vitro osteoinductive potential in early osteogenesis; moreover, histological study was performed to evaluate the BC–COL OGP(10–14) membranes on bone healing after GBR in noncritical defects in rat femur. The results showed that the BC–COL and BC–COL OGP(10–14) membranes promoted cell proliferation and alkaline phosphatase activity in osteoblastic cell cultures. However, ECMmineralization was similar between cultures grown on BC OGP(10–14) and BC–COL OGP(10–14) membranes. In vivo results showed that all the membranes tested, including the peptide-free BC membrane, promoted better bone regeneration than control group. Furthermore, the BC–COL OGP(10–14) membranes induced higher radiographic density in the repaired bone than the other groups at 1, 4 and 16 weeks. Histomorpho-metric analyses revealed that the BC–COL OGP(10–14) induced higher percentage of bone tissue in the repaired area at 2 and 4 weeks than others membranes. In general, these biopolymer-based membranes might be potential candidates for bone regeneration applications

    A comprehensive assessment of the transcriptome of cork oak (Quercus suber) through EST sequencing

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    Background: Cork oak (Quercus suber) is one of the rare trees with the ability to produce cork, a material widely used to make wine bottle stoppers, flooring and insulation materials, among many other uses. The molecular mechanisms of cork formation are still poorly understood, in great part due to the difficulty in studying a species with a long life-cycle and for which there is scarce molecular/genomic information. Cork oak forests are of great ecological importance and represent a major economic and social resource in Southern Europe and Northern Africa. However, global warming is threatening the cork oak forests by imposing thermal, hydric and many types of novel biotic stresses. Despite the economic and social value of the Q. suber species, few genomic resources have been developed, useful for biotechnological applications and improved forest management. Results: We generated in excess of 7 million sequence reads, by pyrosequencing 21 normalized cDNA libraries derived from multiple Q. suber tissues and organs, developmental stages and physiological conditions. We deployed a stringent sequence processing and assembly pipeline that resulted in the identification of ~159,000 unigenes. These were annotated according to their similarity to known plant genes, to known Interpro domains, GO classes and E.C. numbers. The phylogenetic extent of this ESTs set was investigated, and we found that cork oak revealed a significant new gene space that is not covered by other model species or EST sequencing projects. The raw data, as well as the full annotated assembly, are now available to the community in a dedicated web portal at http://www.corkoakdb.org. Conclusions: This genomic resource represents the first trancriptome study in a cork producing species. It can be explored to develop new tools and approaches to understand stress responses and developmental processes in forest trees, as well as the molecular cascades underlying cork differentiation and disease response.Peer Reviewe

    The Developing Human Connectome Project Neonatal Data Release

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    The Developing Human Connectome Project has created a large open science resource which provides researchers with data for investigating typical and atypical brain development across the perinatal period. It has collected 1228 multimodal magnetic resonance imaging (MRI) brain datasets from 1173 fetal and/or neonatal participants, together with collateral demographic, clinical, family, neurocognitive and genomic data from 1173 participants, together with collateral demographic, clinical, family, neurocognitive and genomic data. All subjects were studied in utero and/or soon after birth on a single MRI scanner using specially developed scanning sequences which included novel motion-tolerant imaging methods. Imaging data are complemented by rich demographic, clinical, neurodevelopmental, and genomic information. The project is now releasing a large set of neonatal data; fetal data will be described and released separately. This release includes scans from 783 infants of whom: 583 were healthy infants born at term; as well as preterm infants; and infants at high risk of atypical neurocognitive development. Many infants were imaged more than once to provide longitudinal data, and the total number of datasets being released is 887. We now describe the dHCP image acquisition and processing protocols, summarize the available imaging and collateral data, and provide information on how the data can be accessed

    Autent+ Desenvolvimento de abordagem inovadoras com vista à valorização e exploração do potencial de mercado do mel Português

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    A FENAPICOLA candidatou-se, como proponente, a uma medida de investigação aplicada, tendo convidado o Instituto Politécnico de Bragança (IPB) como entidade parceira, envolvendo este último uma equipa multidisciplinar de 6 investigadores provenientes dos centros de investigação CIMO (Centro de Investigação de Montanha) e CEDRI (Centro de Investigação em Digitalização e Robótica Inteligente). Assim foi criado o projeto AUTENT+, um projeto financiado pelo Instituto de Financiamento da Agricultura e Pescas (IFAP), em resultado da candidatura submetida ao Plano Apícola Nacional (PAN) 2020/2022, medida 5.1 "Apoio a projetas de investigação aplicada”. O AUTENT + tem como principal objetivo a valorização do mel nacional como um produto autêntico e sustentável, através de abordagens que visam diferenciar, acrescentar valor e o potencial de mercado a este produto. Para tal, o projeto centra-se no desenvolvimento de metodologias inovadoras com vista à deteção de adulterações do mel, em particular no que respeita à origem botânica e entomológica/geográfica, e no desenvolvimento de ferramentas que permitam , de uma forma simples, informar o consumidor sobre as caraterísticas do produto que adquirem.Os autores agradecem o financiamento do projeto ao Programa Apícola Nacional 2020-2022 e à Fundação para a Ciência e Tecnologia (FCT, Portugal) pelo apoio financeiro ao CIMO UIDB/00690/2020 através de fundos nacionais FCT/MCTES.info:eu-repo/semantics/publishedVersio

    Accelerated magnetic resonance fingerprinting using soft-weighted key-hole (MRF-SOHO)

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    <div><p>Object</p><p>To develop a novel approach for highly accelerated Magnetic Resonance Fingerprinting (MRF) acquisition.</p><p>Materials and methods</p><p>The proposed method combines parallel imaging, soft-gating and key-hole approaches to highly accelerate MRF acquisition. Slowly varying flip angles (FA), commonly used during MRF acquisition, lead to a smooth change in the signal contrast of consecutive time-point images. This assumption enables sharing of high frequency data between different time-points, similar to what is done in some dynamic MR imaging methods such as key-hole. The proposed approach exploits this information using a SOft-weighted key-HOle (MRF-SOHO) reconstruction to achieve high acceleration factors and/or increased resolution without compromising image quality or increasing scan time. MRF-SOHO was validated on a standard T<sub>1</sub>/T<sub>2</sub> phantom and in <i>in-vivo</i> brain acquisitions reconstructing T<sub>1</sub>, T<sub>2</sub> and proton density parametric maps.</p><p>Results</p><p>Accelerated MRF-SOHO using less data per time-point and less time-point images enabled a considerable reduction in scan time (up to 4.6x), while obtaining similar T<sub>1</sub> and T<sub>2</sub> accuracy and precision when compared to zero-filled MRF reconstruction. For the same number of spokes and time-points, the proposed method yielded an enhanced performance in quantifying parameters than the zero-filled MRF reconstruction, which was verified with 2, 1 and 0.7 (sub-millimetre) resolutions.</p><p>Conclusion</p><p>The proposed MRF-SOHO enabled a 4.6x scan time reduction for an in-plane spatial resolution of 2x2 mm<sup>2</sup> when compared to zero-filled MRF and enabled sub-millimetric (0.7x0.7 mm<sup>2</sup>) resolution MRF.</p></div

    T<sub>1</sub> and T<sub>2</sub> measurement plots (in ms) with zero-filled MRF and the proposed MRF-SOHO reconstructions, using 8 spokes, 1000 time points; 5 spokes, 500 time points; and 2 spokes, 350 time points.

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    <p>An underestimation of T<sub>1</sub> was observed for zero-filled MRF and an overestimation of T<sub>2</sub> was observed for both methods. MRF-SOHO produced more accurate and precise measurements than zero-filled MRF, particularly when less data (time points and radial spokes) was used. Ground truth values were used according to (26).</p

    Pictorial diagram of MRF-SOHO’s data sharing scheme.

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    <p>The example depicted features a neighbourhood size (N) of 5, with one radial profile per flip angle (N<sub>p</sub>). The transparency of colour indicates the fraction of data shared. The farther away the time-point, the less low frequency data is shared.</p
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