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  1. Article ; Online: The Role of Bacteria–Mitochondria Communication in the Activation of Neuronal Innate Immunity

    João D. Magalhães / Ana Raquel Esteves / Emanuel Candeias / Diana F. Silva / Nuno Empadinhas / Sandra Morais Cardoso

    International Journal of Molecular Sciences, Vol 24, Iss 4339, p

    Implications to Parkinson’s Disease

    2023  Volume 4339

    Abstract: Mitochondria play a key role in regulating host metabolism, immunity and cellular homeostasis. Remarkably, these organelles are proposed to have evolved from an endosymbiotic association between an alphaproteobacterium and a primitive eukaryotic host ... ...

    Abstract Mitochondria play a key role in regulating host metabolism, immunity and cellular homeostasis. Remarkably, these organelles are proposed to have evolved from an endosymbiotic association between an alphaproteobacterium and a primitive eukaryotic host cell or an archaeon. This crucial event determined that human cell mitochondria share some features with bacteria, namely cardiolipin, N-formyl peptides, mtDNA and transcription factor A, that can act as mitochondrial-derived damage-associated molecular patterns (DAMPs). The impact of extracellular bacteria on the host act largely through the modulation of mitochondrial activities, and often mitochondria are themselves immunogenic organelles that can trigger protective mechanisms through DAMPs mobilization. In this work, we demonstrate that mesencephalic neurons exposed to an environmental alphaproteobacterium activate innate immunity through toll-like receptor 4 and Nod-like receptor 3. Moreover, we show that mesencephalic neurons increase the expression and aggregation of alpha-synuclein that interacts with mitochondria, leading to their dysfunction. Mitochondrial dynamic alterations also affect mitophagy which favors a positive feedback loop on innate immunity signaling. Our results help to elucidate how bacteria and neuronal mitochondria interact and trigger neuronal damage and neuroinflammation and allow us to discuss the role of bacterial-derived pathogen-associated molecular patterns (PAMPs) in Parkinson’s disease etiology.
    Keywords mitochondria ; alphaproteobacteria ; innate immunity ; antimicrobial peptides ; α-Synuclein ; Biology (General) ; QH301-705.5 ; Chemistry ; QD1-999
    Subject code 571
    Language English
    Publishing date 2023-02-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Self-recycling and partially conservative replication of mycobacterial methylmannose polysaccharides

    Ana Maranha / Mafalda Costa / Jorge Ripoll-Rozada / José A. Manso / Vanessa Miranda / Vera M. Mendes / Bruno Manadas / Sandra Macedo-Ribeiro / M. Rita Ventura / Pedro José Barbosa Pereira / Nuno Empadinhas

    Communications Biology, Vol 6, Iss 1, Pp 1-

    2023  Volume 17

    Abstract: The mechanism of methylmannose polysaccharide (MMP) biogenesis in nontuberculous mycobacteria (NTM) is characterized, which involves an MMP-specific hydrolase (MmpH) and a rare mannosyltransferase (ManT). MmpH and ManT structures are presented. ...

    Abstract The mechanism of methylmannose polysaccharide (MMP) biogenesis in nontuberculous mycobacteria (NTM) is characterized, which involves an MMP-specific hydrolase (MmpH) and a rare mannosyltransferase (ManT). MmpH and ManT structures are presented.
    Keywords Biology (General) ; QH301-705.5
    Language English
    Publishing date 2023-01-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: The structural characterization of a glucosylglycerate hydrolase provides insights into the molecular mechanism of mycobacterial recovery from nitrogen starvation

    Tatiana Barros Cereija / Susana Alarico / Eva C. Lourenço / José António Manso / M. Rita Ventura / Nuno Empadinhas / Sandra Macedo-Ribeiro / Pedro José Barbosa Pereira

    IUCrJ, Vol 6, Iss 4, Pp 572-

    2019  Volume 585

    Abstract: Bacteria are challenged to adapt to environmental variations in order to survive. Under nutritional stress, several bacteria are able to slow down their metabolism into a nonreplicating state and wait for favourable conditions. It is almost universal ... ...

    Abstract Bacteria are challenged to adapt to environmental variations in order to survive. Under nutritional stress, several bacteria are able to slow down their metabolism into a nonreplicating state and wait for favourable conditions. It is almost universal that bacteria accumulate carbon stores to survive during this nonreplicating state and to fuel rapid proliferation when the growth-limiting stress disappears. Mycobacteria are exceedingly successful in their ability to become dormant under harsh circumstances and to be able to resume growth when conditions are favourable. Rapidly growing mycobacteria accumulate glucosylglycerate under nitrogen-limiting conditions and quickly mobilize it when nitrogen availability is restored. The depletion of intracellular glucosylglycerate levels in Mycolicibacterium hassiacum (basonym Mycobacterium hassiacum) was associated with the up-regulation of the gene coding for glucosylglycerate hydrolase (GgH), an enzyme that is able to hydrolyse glucosylglycerate to glycerate and glucose, a source of readily available energy. Highly conserved among unrelated phyla, GgH is likely to be involved in bacterial reactivation following nitrogen starvation, which in addition to other factors driving mycobacterial recovery may also provide an opportunity for therapeutic intervention, especially in the serious infections caused by some emerging opportunistic pathogens of this group, such as Mycobacteroides abscessus (basonym Mycobacterium abscessus). Using a combination of biochemical methods and hybrid structural approaches, the oligomeric organization of M. hassiacum GgH was determined and molecular determinants of its substrate binding and specificity were unveiled.
    Keywords MhGgH ; GH63 ; glycoside hydrolase ; Mycolicibacterium hassiacum ; protein structure ; molecular recognition ; X-ray crystallography ; enzyme mechanism ; solution scattering ; Science ; Q
    Language English
    Publishing date 2019-07-01T00:00:00Z
    Publisher International Union of Crystallography
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article: Hospital microbial surface colonization revealed during monitoring of Klebsiella spp., Pseudomonas aeruginosa, and non-tuberculous mycobacteria

    Geadas Farias, Pedro / Fernando Gama / Diogo Reis / Susana Alarico / Nuno Empadinhas / José Carlos Martins / Ana Figueiredo de Almeida / Paula Vasconcelos Morais

    Antonie van Leeuwenhoek. 2017 July, v. 110, no. 7

    2017  

    Abstract: Hospital environmental conditions, human occupancy, and the characteristics of the equipment influence the survival of microbial communities and raise a concern with regard to nosocomial infections. The objective of the present work was to use the ... ...

    Abstract Hospital environmental conditions, human occupancy, and the characteristics of the equipment influence the survival of microbial communities and raise a concern with regard to nosocomial infections. The objective of the present work was to use the monitoring of Pseudomonas aeruginosa, Klebsiella spp. and non-tuberculous mycobacteria as a strategy to improve knowledge on microbial colonization of non-critical equipment and surfaces, in a tertiary hospital from Central Portugal. A 3-month microbiological survey was performed in a district teaching hospital. A total of 173 samples were obtained from the wards Hematology, Urology, Medicine, and Renal Transplants, and 102 presumptive strains recovered. Per sampling, Pseudomonas Isolation agar showed 42.8 to 73.3% of presumptive P. aeruginosa colonies and MacConkey agar recovered mostly Staphylococcus. Most of the colonies recovered in Middlebrook 7H10-PANTA belonged to the genus Methylobacterium. Taps and WC shower curtains carry high bacterial species diversity. The Redundancy Analysis grouped the samples in those mostly handled by patients, and those mostly handled by healthcare staff or of mixed use. This study shows that the preferential users of the space and equipment seem to be important contributors to the microbial community. The most recovered genus was Methylobacterium, known as colonizer of the water distribution system therefore, it is possible that the water points and biofilms in taps also contribute as dispersion hotspots.
    Keywords Klebsiella ; Methylobacterium ; Pseudomonas aeruginosa ; Staphylococcus ; agar ; biofilm ; environmental factors ; equipment ; health services ; hospitals ; humans ; microbial colonization ; microbial communities ; monitoring ; patients ; species diversity ; surveys ; water distribution ; Portugal
    Language English
    Dates of publication 2017-07
    Size p. 863-876.
    Publishing place Springer International Publishing
    Document type Article
    ZDB-ID 214861-4
    ISSN 1572-9699 ; 0003-6072
    ISSN (online) 1572-9699
    ISSN 0003-6072
    DOI 10.1007/s10482-017-0857-z
    Database NAL-Catalogue (AGRICOLA)

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  5. Article ; Online: Mycobacterium tuberculosis glucosyl-3-phosphoglycerate synthase

    Pedro José Barbosa Pereira / Nuno Empadinhas / Luciana Albuquerque / Bebiana Sá-Moura / Milton S da Costa / Sandra Macedo-Ribeiro

    PLoS ONE, Vol 3, Iss 11, p e

    structure of a key enzyme in methylglucose lipopolysaccharide biosynthesis.

    2008  Volume 3748

    Abstract: Tuberculosis constitutes today a serious threat to human health worldwide, aggravated by the increasing number of identified multi-resistant strains of Mycobacterium tuberculosis, its causative agent, as well as by the lack of development of novel ... ...

    Abstract Tuberculosis constitutes today a serious threat to human health worldwide, aggravated by the increasing number of identified multi-resistant strains of Mycobacterium tuberculosis, its causative agent, as well as by the lack of development of novel mycobactericidal compounds for the last few decades. The increased resilience of this pathogen is due, to a great extent, to its complex, polysaccharide-rich, and unusually impermeable cell wall. The synthesis of this essential structure is still poorly understood despite the fact that enzymes involved in glycosidic bond synthesis represent more than 1% of all M. tuberculosis ORFs identified to date. One of them is GpgS, a retaining glycosyltransferase (GT) with low sequence homology to any other GTs of known structure, which has been identified in two species of mycobacteria and shown to be essential for the survival of M. tuberculosis. To further understand the biochemical properties of M. tuberculosis GpgS, we determined the three-dimensional structure of the apo enzyme, as well as of its ternary complex with UDP and 3-phosphoglycerate, by X-ray crystallography, to a resolution of 2.5 and 2.7 A, respectively. GpgS, the first enzyme from the newly established GT-81 family to be structurally characterized, displays a dimeric architecture with an overall fold similar to that of other GT-A-type glycosyltransferases. These three-dimensional structures provide a molecular explanation for the enzyme's preference for UDP-containing donor substrates, as well as for its glucose versus mannose discrimination, and uncover the structural determinants for acceptor substrate selectivity. Glycosyltransferases constitute a growing family of enzymes for which structural and mechanistic data urges. The three-dimensional structures of M. tuberculosis GpgS now determined provide such data for a novel enzyme family, clearly establishing the molecular determinants for substrate recognition and catalysis, while providing an experimental scaffold for the structure-based rational design of ...
    Keywords Medicine ; R ; Science ; Q
    Subject code 572
    Language English
    Publishing date 2008-01-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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