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  1. 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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  2. Article ; Online: Peptidomics Unveils Distinct Acetylation Patterns of Histone and Annexin A1 in Differentiated Thyroid Cancer

    Margarida Coelho / João Capela / Vera M. Mendes / João Pacheco / Margarida Sá Fernandes / Isabel Amendoeira / John G. Jones / Luís Raposo / Bruno Manadas

    International Journal of Molecular Sciences, Vol 25, Iss 1, p

    2023  Volume 376

    Abstract: Thyroid cancer is a common malignancy of the endocrine system. Nodules are routinely evaluated for malignancy risk by fine needle aspiration biopsy (FNAB), and in cases such as follicular lesions, differential diagnosis between benign and malignant ... ...

    Abstract Thyroid cancer is a common malignancy of the endocrine system. Nodules are routinely evaluated for malignancy risk by fine needle aspiration biopsy (FNAB), and in cases such as follicular lesions, differential diagnosis between benign and malignant nodules is highly uncertain. Therefore, the discovery of new biomarkers for this disease could be helpful in improving diagnostic accuracy. Thyroid nodule biopsies were subjected to a precipitation step with both the insoluble and supernatant fractions subjected to proteome and peptidome profiling. Proteomic analysis identified annexin A1 as a potential biomarker of thyroid cancer malignancy, with its levels increased in malignant samples. Also upregulated were the acetylated peptides of annexin A1, revealed by the peptidome analysis of the supernatant fraction. In addition, supernatant peptidomic analysis revealed a number of acetylated histone peptides that were significantly elevated in the malignant group, suggesting higher gene transcription activity in malignant tissue. Two of these peptides were found to be robust malignancy predictors, with an area under the receiver operating a characteristic curve (ROC AUC) above 0.95. Thus, this combination of proteomics and peptidomics analyses improved the detection of malignant lesions and also provided new evidence linking thyroid cancer development to heightened transcription activity. This study demonstrates the importance of peptidomic profiling in complementing traditional proteomics approaches.
    Keywords peptidomics ; proteomics ; tissue ; LC-MS/MS ; biomarker ; thyroid cancer ; Biology (General) ; QH301-705.5 ; Chemistry ; QD1-999
    Subject code 610
    Language English
    Publishing date 2023-12-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Validation of an LC-MS/MS Method for the Quantification of Caffeine and Theobromine Using Non-Matched Matrix Calibration Curve

    Vera M. Mendes / Margarida Coelho / Angelo R. Tomé / Rodrigo A. Cunha / Bruno Manadas

    Molecules, Vol 24, Iss 16, p

    2019  Volume 2863

    Abstract: Caffeine is one of the most widely consumed psycho-stimulants. The study of the beneficial effects of caffeine consumption to decrease the risk of developing several neuropsychiatric pathologies is receiving increasing attention. Thus, accurate and ... ...

    Abstract Caffeine is one of the most widely consumed psycho-stimulants. The study of the beneficial effects of caffeine consumption to decrease the risk of developing several neuropsychiatric pathologies is receiving increasing attention. Thus, accurate and sensitive methods have been developed, mainly by LC-MS/MS, in order to quantify caffeine and its metabolites. These quantifications of caffeine and its metabolites by LC-MS/MS require a considerable effort to select or find a surrogate matrix, without the compounds of interest, to be used in the calibration curves. Thus, we evaluated the possibility of using calibration curves prepared in solvent instead of calibration curves prepared in human plasma. Results show that the calibration curves prepared in solvent and in human plasma were similar by comparing their slopes and interceptions, and the accuracy and precision were within the limits of acceptance for both calibration curves. This work demonstrates that, by using internal standards, it is possible to use a calibration curve in solvent instead of a calibration curve in plasma to perform an accurate and precise quantification of caffeine and theobromine.
    Keywords caffeine ; LC-MS/MS ; non-matched matrix calibration curve ; Organic chemistry ; QD241-441
    Language English
    Publishing date 2019-08-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Specific Antiproliferative Properties of Proteinaceous Toxin Secretions from the Marine Annelid Eulalia sp. onto Ovarian Cancer Cells

    Ana P. Rodrigo / Vera M. Mendes / Bruno Manadas / Ana R. Grosso / António P. Alves de Matos / Pedro V. Baptista / Pedro M. Costa / Alexandra R. Fernandes

    Marine Drugs, Vol 19, Iss 1, p

    2021  Volume 31

    Abstract: As Yondelis joins the ranks of approved anti-cancer drugs, the benefit from exploring the oceans’ biodiversity becomes clear. From marine toxins, relevant bioproducts can be obtained due to their potential to interfere with specific pathways. We explored ...

    Abstract As Yondelis joins the ranks of approved anti-cancer drugs, the benefit from exploring the oceans’ biodiversity becomes clear. From marine toxins, relevant bioproducts can be obtained due to their potential to interfere with specific pathways. We explored the cytotoxicity of toxin-bearing secretions of the polychaete Eulalia onto a battery of normal and cancer human cell lines and discovered that the cocktail of proteins is more toxic towards an ovarian cancer cell line (A2780). The secretions’ main proteins were identified by proteomics and transcriptomics: 14-3-3 protein, Hsp70, Rab3, Arylsulfatase B and serine protease, the latter two being known toxins. This mixture of toxins induces cell-cycle arrest at G2/M phase after 3h exposure in A2780 cells and extrinsic programmed cell death. These findings indicate that partial re-activation of the G2/M checkpoint, which is inactivated in many cancer cells, can be partly reversed by the toxic mixture. Protein–protein interaction networks partake in two cytotoxic effects: cell-cycle arrest with a link to RAB3C and RAF1; and lytic activity of arylsulfatases. The discovery of both mechanisms indicates that venomous mixtures may affect proliferating cells in a specific manner, highlighting the cocktails’ potential in the fine-tuning of anti-cancer therapeutics targeting cell cycle and protein homeostasis.
    Keywords invertebrate ; cytotoxicity ; cancer ; ovarian cancer ; programmed cell death ; cell cycle ; Biology (General) ; QH301-705.5
    Subject code 616
    Language English
    Publishing date 2021-01-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article: Bioaccessibility and changes on cylindrospermopsin concentration in edible mussels with storage and processing time

    Freitas, Marisa / Alexandre Campos / António Paulo Carvalho / Bruno Manadas / Joana Azevedo / Vera M. Mendes / Vitor Vasconcelos

    Food control. 2016 Jan., v. 59

    2016  

    Abstract: The alkaloid cylindrospermopsin has been recognized of increased concern due to the global expansion of its main producer, Cylindrospermopsis raciborskii. Previous studies have shown that bivalves can accumulate high levels of cylindrospermopsin. Based ... ...

    Abstract The alkaloid cylindrospermopsin has been recognized of increased concern due to the global expansion of its main producer, Cylindrospermopsis raciborskii. Previous studies have shown that bivalves can accumulate high levels of cylindrospermopsin. Based on the potential for human health risks, a provisional tolerable daily intake of 0.03 μg/kg-body weight has been recommended. However, the human exposure assessment has been based on the cylindrospermopsin concentration in raw food items. Thus, this study aimed to assess the changes on cylindrospermopsin concentration in edible mussels with storage and processing time as well as cylindrospermopsin bioaccessibility. Mussels, (Mytilus galloprovincialis) fed cylindrospermopsin-producing C. raciborskii, were subjected to the treatments and then analyzed by LC-MS/MS. Mussels stored frozen allowed a significantly higher recovery of cylindrospermopsin (52.5% in 48 h and 57.7% in one week). The cooking treatments did not produce significant differences in cylindrospermopsin concentration in the mussel matrices (flesh), however, cylindrospermopsin was found in the cooking water, suggesting that heat processing can be used to reduce the availability of cylindrospermopsin. The in vitro digestion considerably decreased the cylindrospermopsin availability in uncooked and steamed mussels, highlighting the importance in integrating the bioaccessibility of cylindrospermopsinin in the human health risk assessment.
    Keywords acceptable daily intake ; alkaloids ; bioavailability ; cooking ; cylindrospermopsin ; Cylindrospermopsis raciborskii ; exposure assessment ; heat treatment ; human health ; humans ; in vitro digestion ; mussels ; Mytilus galloprovincialis ; raw foods ; risk
    Language English
    Dates of publication 2016-01
    Size p. 567-574.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 1027805-9
    ISSN 0956-7135
    ISSN 0956-7135
    DOI 10.1016/j.foodcont.2015.06.025
    Database NAL-Catalogue (AGRICOLA)

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  6. Article: Direct analysis of [6,6-2H2]glucose and [U-13C6]glucose dry blood spot enrichments by LC–MS/MS

    Coelho, Margarida / Ana B. Fernandes / Bruno Manadas / Fátima O. Martins / Inês S. Lima / John G. Jones / M. Paula Macedo / Vera M. Mendes

    Journal of chromatography. 2016 June 01, v. 1022

    2016  

    Abstract: A liquid chromatography tandem mass spectrometry (LC–MS/MS) using multiple reaction monitoring (MRM) in a triple-quadrupole scan mode was developed and comprehensively validated for the determination of [6,6-2H2]glucose and [U-13C6]glucose enrichments ... ...

    Abstract A liquid chromatography tandem mass spectrometry (LC–MS/MS) using multiple reaction monitoring (MRM) in a triple-quadrupole scan mode was developed and comprehensively validated for the determination of [6,6-2H2]glucose and [U-13C6]glucose enrichments from dried blood spots (DBS) without prior derivatization. The method is demonstrated with dried blood spots obtained from rats administered with a primed-constant infusion of [U-13C6]glucose and an oral glucose load enriched with [6,6-2H2]glucose. The sensitivity is sufficient for analysis of the equivalent to <5μL of blood and the overall method was accurate and precise for the determination of DBS isotopic enrichments.
    Keywords blood ; derivatization ; glucose ; liquid chromatography ; monitoring ; rats ; tandem mass spectrometry
    Language English
    Dates of publication 2016-0601
    Size p. 242-248.
    Publishing place Elsevier B.V.
    Document type Article
    ISSN 1570-0232
    DOI 10.1016/j.jchromb.2016.04.027
    Database NAL-Catalogue (AGRICOLA)

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