Percorrer por autor "Teixeira, Dulce"
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- 3-Nitrotyrosine quantification methods: Current concepts and future challengesPublication . Teixeira, Dulce; Fernandes, Rúben; Prudêncio, Cristina; Vieira, MónicaMeasurement of 3-nitrotyrosine (3-NT) in biological samples can be used as a biomarker of nitrosative stress, since it is very stable and suitable for analysis. Increased 3-NT levels in biological samples have been associated with several physiological and pathological conditions. Different methods have been described for the detection and quantification of this molecule, such as (i) immunological methods; (ii) liquid chromatography, namely high-pressure liquid chromatography (HPLC)-based methods that use ultraviolet-visible (UV/VIS) absorption, electrochemical (ECD) and diode array (DAD) detection, liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS); (iii) gas chromatography, such as gas chromatography-mass spectrometry (GC-MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS). Methods A literature review on nitrosative stress, protein nitration, as well as 3-NT quantification methods was carried out. Results This review covers the different methods for analysis of 3-NT that have been developed during the last years as well as the latest advances in this field. Overall, all methods present positive and negative aspects, although it is clear that chromatography-based methods present good sensitivity and specificity. Regarding this, GC-based methods exhibit the highest sensibility in the quantification of 3-NT, although it requires a prior time consuming derivatization step. Conversely, HPLC does not require such derivatization step, despite being not as accurate as GC. Conclusion It becomes clear that all the methods described during this literature review, although accurate for 3-NT quantification, need to be improved regarding both sensitivity and specificity. Moreover, optimization of the protocols that have been described is clearly needed.
- Biotechnology and biochemistry laboratorial education through the SARS-CoV2 pandemic: challenges, truths and takeawaysPublication . Almeida, Joana; Pereira, Cassilda; Coelho, Pedro; Teixeira, Dulce; Louçano, Marta; Bento, C.; Cerqueira, Maria João; Prudêncio, Cristina; Ferraz, Ricardo; Vieira, MónicaIn early 2020, the COVID-19 pandemic forced the higher education institutions to adapt to a new form of teaching and learning, from presential to full remote, blended and hybrid environment.
- Book of abstracts 4th Meeting on Medicinal Biotechnology (4EBtM)Publication . Costa, Ana Rita; Dias, Ana Rita; Prudêncio, Cristina; Borges, Cristina; Teixeira, Dulce; Almeida, Joana; Vieira, Mónica; Coelho, Pedro; Ferraz, Ricardo; Cunha, SofiaThese meetings have been held once a year since 2015 and have played an important role as a point of contact among several professionals and students in Medicinal Biotechnology. Like the Medicinal Biotechnology field itself, these meetings have also been expanding, not only in the number of participants, but also in their geographical origin. Therefore, it is our goal to act as an interface between students and biotechnology companies/researchers, as well as to increasingly promote networking, projects and collaborations within this field for the upcoming years.
- Book of Abstracts of 5th Meeting of Medicinal Biotechnology (5MBtM) and 2nd Iberian Congress on Medicinal BiotechnologyPublication . Sieiro, Carmen; Pereira, Cassilda; Prudêncio, Cristina; Oliveira, Daniela; Teixeira, Dulce; Barros, Eduarda; Almeida, Joana; Cerqueira, Maria João; Louçano, Marta; Vieira, Mónica; Coelho, Pedro; Ferraz, Ricardo
- Book of abstracts of the III Encontro de Biotecnologia Medicinal/ I Iberian Congress on Medicinal BiotechnologyPublication . Costa, Ana Rita; Prudêncio, Cristina; Teixeira, Dulce; Almeida, Joana; Vieira, Mónica; Coelho, Pedro; Ferraz, Ricardo; Cunha, Sofia; Dias, Ana RitaEstes encontros de Biotecnologia Medicinal iniciaram-se em 2015 e sentimos que estamos a crescer, tal como a Biotecnologia Medicinal. Esta área da Biotecnologia tem ganho relevância, quer em empresas, quer a nível académico, criando interfaces entre a biologia molecular, a microbiologia e a química medicinal.
- Desenvolvimento, avaliação e quantificação de biomoléculasPublication . Teixeira, Dulce; Ferraz, Ricardo; Prudêncio, Cristina; Vieira, MónicaThe synthesis of new biomolecules, the evaluation of their potential biological activity or therapeutic application, as well as the monitoring of intervening biomolecules in pathological contexts is of great interest to the scientific, medical and pharmaceutical community. In the validation of synthesis, extraction and biological interaction methods, chromatographic methods play a fundamental role in the identification and quantification of these biomolecules of interest, whether these are potential new drugs, biomarkers or environmental indicators. In order to contribute to the identification and quantification of biomolecules with potential (bio) technological application, new chromatographic methodologies have been developed, namely based on liquid chromatography, using HPLC-DAD. In the development of new biomolecules, the bioactivity of compounds with potential application has been studied, such as Quinoxaline derivatives. In addition to the antimicrobiological action, the effect of this family of compounds in the modeling of oxidative stress in pathological context has been evaluated.
- Development of a chromatographic method for simultaneous analysis of glutathione formsPublication . Teixeira, Dulce; Coelho, Pedro; Prudêncio, Cristina; Azenha, Manuel; Vieira, MónicaReduced glutathione (GSH)is the most abundant low molecular weight thiol-containing tripeptide (glycine, cysteine, and glutamate) which is synthesized in the cells. GSHplays critical roles in protecting cells from oxidative damage and the toxicity of xenobiotics. Besides, it is also involved in the regulation of intracellular redox homeostasis, which leads to its oxidation into oxidized glutathione (GSSG). Determining the ratio of GSH/GSSG in different biological samples is a major procedure for the evaluation of an individual’s oxidative status and can be a potential biomarker of oxidative stress.
- Development of a method based on HPLC-DAD for the detection and quantification of glutamate and gamma-aminobutyric acidPublication . Machado, Patrícia; Teixeira, Dulce; Vieira, Mónica; Prudêncio, CristinaWith the increasing incidence of neurodegenerative diseases, the need arose to study several molecules that may be useful to the study of new therapies and to treat the symptoms that come with these diseases, as is the case of depression. GABA and glutamate have a very important role in the homeostasis of the organism and molecules of interest and potential from the point of view of diagnosis are revealed. HPLC is a method that allows the detection and quantification of various analytes in different biological matrices, allowing rapid results with high precision, sensitivity and specificity.
- Development of a new HPLC-based method for 3-nitrotyrosine quantification in different biological matricesPublication . Teixeira, Dulce; Prudêncio, Cristina; Vieira, MónicaThe nitration of tyrosine residues in proteins is associated with nitrosative stress, resulting in the formation of 3-nitrotyrosine (3-NT).1 3-NT levels in biological samples have been associated with numerous physiological and pathological conditions. Hence several attempts have been made in order to develop methods that accurately quantify 3-NT in these matrices.The aim of this study was to develop a simple, rapid, low-cost and sensitive high-performance liquid chromatography (HPLC)-based 3-NT quantification method. Methods All experiments were performed on an Hitachi LaChrom Elite® HPLC system. The method was validated according to International Conference on Harmonisation (ICH) guidelines for serum samples. Additionally, other biological matrices were tested, namely whole blood, urine, B16 F-10 melanoma cell line, growth medium conditioned with the same cell line, bacterial and yeast suspensions. Results From all the protocols tested, the best results were obtained using 0.5% CH3COOH:MeOH:H2O (15:15:70) as mobile phase, with detection at wavelengths 215, 276 and 356 nm, at 25 °C, and using a flow rate of 1 mL min−1. By using this protocol, it was possible to obtain a linear calibration curve, limits of detection and quantification in the order of μg L−1, and a short analysis time (<15 min per sample). The developed protocol allowed the successful detection and quantification of 3-NT in all biological matrices tested, with detection at 356 nm. Conclusion This method, successfully developed and validated for 3-NT quantification, is simple, cheap and fast. These features render this method a suitable option for analysis of a wide range of biological matrices, being a promising useful tool for both research and diagnosis activities.
- Development of a new method for the detection and quantification of 3-nitrotyrosinePublication . Teixeira, Dulce; Prudêncio, Cristina; Fernandes, Rúben; Vieira, MónicaThe nitration of Tyrosine residues in proteins is associated with nitrosative stress, resulting in the formation of 3-nitrotyrosine (3-NT). Different methods have been described for the quantification of this molecule. Regarding chromatographic methods, they seem to be very accurate, showing very good sensibility and specificity. Gas chromatography-based methods exhibit the highest sensibility, however a derivatization step prior analysis is required, which ends up being time-consuming for the analyst. Conversely, High Performance Liquid Chromatography (HPLC) may not require such derivatization.