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37 results on '"Moreirinha, Catarina"'

5. Paralytic Shellfish Toxin Extraction from Bivalve Meat for Analysis Using Potentiometric Chemical Sensors.

Author

Cerqueira, Ana Filipa R., Moreirinha, Catarina, Raposo, Mariana, Gomes, Maria Teresa S. R., Costa, Sara T., Botelho, Maria João, and Rudnitskaya, Alisa

Subjects
PARALYTIC shellfish toxins, CHEMICAL detectors, ANALYTICAL chemistry, MEAT analysis, POTENTIOMETRY, SHELLFISH
Abstract

A simple and reliable methodology for the detection of paralytic shellfish toxins (PSTs) in bivalve tissues using potentiometric chemical sensors was developed. Five methods of PST extraction from mussel and oyster tissues were evaluated, including the AOAC-recommended method, which served as the reference. The main objective was to minimize the matrix effect of the extracts on the sensors' responses and ensure efficient toxin recovery. Extraction procedures using acetic acid with heating and water yielded the highest responses from the potentiometric chemical sensors to PSTs. The highest recovery of PSTs from bivalve tissues was achieved with extraction using acetic acid and heating. Further extract purification, which is indispensable for liquid chromatography with fluorometric detection (LC-FLD) analysis, was found to be unnecessary for analysis with chemical sensors. While water extraction can also be used as a rapid and simple PST extraction method, the lower recoveries should be considered when interpreting the results. Further research is needed to identify the compounds remaining in the extracts that cause a decrease in sensor responses and to develop procedures for their elimination. [ABSTRACT FROM AUTHOR]

Published
2024
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15. Conversion of antibacterial activity of graphene‐coated textiles through surface polarity.

Author

Rodrigues, Daniela P., Moreirinha, Catarina, Rajan, Gopika, Neves, Ana I. S., Freitas, Sidónio C., Sequeira, Sara, Russo, Saverio, Craciun, Monica F., Almeida, Adelaide, and Alves, Helena

Subjects
ANTIBACTERIAL agents, CHARGE transfer, GRAM-positive bacteria, GRAM-negative bacteria, GRAPHENE, SURFACE charges, GRAPHENE oxide
Abstract

Graphene is emerging in numerous wearable and biomedical applications. Understanding the impact of graphene‐based nanocomposites over bacterial activity is critical for design appropriate technical solutions. In this work, antibacterial activity of monolayer and few‐layer graphene is tested against Gram‐negative and Gram‐positive model bacteria. Such graphene‐based nanomaterials present different effects on bacteria viability, depending on concentration and shape. The presence of dopant agents can either increase or revert graphene antibacterial effect. Among other bactericidal mechanisms, we also demonstrate that graphene surface polarity is connected to antibacterial properties and can be easily modified by surface charge transfer doping. This electrophilicity tuning offers a novel mechanism for the molecular basis of graphene's antibacterial activity. [ABSTRACT FROM AUTHOR]

Published
2023
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22. The Health-Promoting Potential of Salix spp. Bark Polar Extracts: Key Insights on Phenolic Composition and In Vitro Bioactivity and Biocompatibility

Author

Ramos, Patrícia A. B., primary, Moreirinha, Catarina, additional, Silva, Sara, additional, Costa, Eduardo M., additional, Veiga, Mariana, additional, Coscueta, Ezequiel, additional, Santos, Sónia A. O., additional, Almeida, Adelaide, additional, Pintado, M. Manuela, additional, Freire, Carmen S. R., additional, Silva, Artur M. S., additional, and Silvestre, Armando J. D., additional

Published
2019
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27. Phage therapy in aquaculture: in vitro and in vivo studies

Author

Moreirinha, Catarina, Pereira, Carla, and Almeida, Adelaide

Abstract

The fastest growing food animal-producing sector worldwide is aquaculture, providing about 30 percent of the world seafood supply. However, it often suffers from heavy financial losses because of the high mortality caused by bacteria, namely multidrug-resistant bacteria that are easily transmitted through the water and infect a great variety of aquaculture species. Nowadays, phage therapy is considered a potential viable alternative to antibiotics for inactivation of bacteria in aquaculture systems. A major concern of bacterial inactivation by phages is the emergence of phage-resistant bacteria, and few is known about the resistance mechanisms that are developed in the presence of phages. The efficiency of three different phages to inactivate Aeromonas salmonicida was tested in vitro. This bacterium causes furunculosis, a disease characterized by high mortality in aquaculture fish. It was found that all of the three phages (either single or combined in cocktail) decreased the concentration of this bacterium to 4 log. In vivo experiments with two E. coli phages using cockles in a depuration system with recirculating water showed that approximately 2 log of bacteria were inactivated in artificially contaminated cockles, and approximately 0.6 log in naturally contaminated ones. It was also found that the use of phages during depuration decreased bacteria concentration faster than the use of depuration alone, as to achieve the same bacterial concentration decrease, two more hours were needed if no phage was used. Regarding the development of bacterial resistance to phages, it was verified that mutant bacteria rapidly recover their susceptibility to the phages and the colonies grow much slower and small than the susceptible bacteria. Taking this into account, infrared spectroscopy was used to assess the spectral modifications of the bacterial cells that developed resistance. It was found that there were great modifications in the protein spectral region, suggesting that surface proteins, that can be phage receptors, are greatly implied in this process. These results suggest that phage therapy might be the most promising choice to be used in aquaculture fish and during the bivalve depuration to control the transmission of bacteria that can cause economic losses or be harmful to the consumers., Journal of Targeting Infectiuos Diseases, Vol 1, No 1 (2016)

Published
2016
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28. Efficient Catalytic Oxidation of 3-Arylthio- and 3-Cyclohexylthio-lapachone Derivatives to New Sulfonyl Derivatives and Evaluation of Their Antibacterial Activities

Author

Cardoso, Mariana, primary, Gomes, Ana, additional, Moreira, Caroline, additional, Simões, Mário, additional, Neves, Maria, additional, da Rocha, David, additional, da Silva, Fernando, additional, Moreirinha, Catarina, additional, Almeida, Adelaide, additional, Ferreira, Vitor, additional, and Cavaleiro, José, additional

Published
2017
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