Browsing by Author "Veiga, Marlene"
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- Energéticos, o vício silencioso do século XXIPublication . Franco, Carolina; Barbosa, Flávia; Veiga, Marlene; Prudêncio, Cristina; Dores, Artemisa R.A literacia em saúde refere-se à competência do indivíduo para aceder, compreender e usar a informação, de forma a promover e manter uma boa saúde individual, familiar e comunitária. Durante as últimas décadas tem aumentado o interesse em promover um papel mais ativo dos cidadãos em questões de saúde e cuidados para saúde [2]. Muitas das práticas que põem em risco a nossa saúde estão associadas à alimentação e aos produtos ingeridos, como é o caso do consumo de bebidas energéticas. Segundo a literatura, estas têm ganho crescente destaque principalmente entre o público mais jovem. É importante alertar para os malefícios do consumo de bebidas energéticas, dado que alguns estudos têm demonstrado que os seus constituintes (e.g., cafeína, taurina, açúcares) provocam efeitos nefastos ao organismo.
- Oxidative stress genes involved in the virulence-dependent susceptibility to antibiotics in Pseudomonas aeruginosaPublication . Coelho, Pedro Barata; Fernandes, Ruben; Silva, Carina; Oliveira, Marco; Veiga, Marlene; Sá, Sara; Vieira, André; Guedes, Carla; Baylina, PilarPseudomonas aeruginosa is a Gram-negative opportunistic pathogen which rarely causes disease in healthy people. P. aeruginosa, in particular strain PAO1 is also a biological model for studying virulence and bacterial social traits, such as quorum sensing, SOS response among other. Antibiotic response is dependent, among several other factors, to the response to environmental stress conditions. The present study aims to understand the role of 10 PAO1 oxidative gene mutants in the response to antibiotic stress in elastase, protease and pyocyanin-dependent virulence factors. PAO1 was stressed to several antibiotics (penicilins, cephalosporins, macrolides, and quinolones), and the virulence proteins were measured by means of spectroscopic methods. Viability was measured by means of Erythrosin B. PAO1 GGT, GLO1, RubA2, GSH A mutants were the most susceptible to the production of virulence-dependent factors.
- The synergic effect of antibiotics is dependent of oxidative stress genes in Pseudomonas aeruginosaPublication . Fernandes, Rúben; Coelho, Pedro Barata; Guedes, Carla; Gojon, Frantz; Oliveira, Marco; Veiga, Marlene; Sá, Sara; Silva, Carina; Baylina, PilarPseudomonas aeruginosa is a Gram-negative opportunistic pathogen commonly found in Cystic fibrosis, infected wound of the diabetic foot among others. Clinical management of such infection depends deeply on the antibiotic therapy. Antibiotic response is dependent, among several other factors, to the response to host stress conditions, such as low-grade inflammation, metabolic conditions and oxidative stress and to social bacteria response such as quorum sensing and biofilm formation. P. aeruginosa, in particular strain PAO1 is also a biological model for studying bacterial biofilm formation. The present study aims to understand the antibiotic synergic response (ampicillin, ceftazidime, ciprofloxacin) in biofilm formation / degradation of 10 PAO1 oxidative gene mutants. Viability was measured by means of Erythrosin B and biofilm formation was measured by Crystal Violet assay. PAO1 GRLX, SEPHS 1, Rub A1, where the strains with a most pronounced biofilm formation and combination of ceftazidme::ciprofloxacin were most efficient in this biological model. The results are interesting, and although they are encouraging, they should be taken with caution.
- Virulence-linked mutations in rubredoxin reductase and glutaredoxin: impact on antibiotic susceptibility and phage therapy in Pseudomonas aeruginosaPublication . Sá, Sara; Silva, Carina; Dias, Maria Clara; Veiga, Marlene; Lopes, Sofia; Fernandes, Ruben; Rocha, Ana Catarina; Pais, Patrick J.; Oliveira, Marco; Mendes, João; Novais, Gonçalo; Luís, Carla; Gestoso, Álvaro; Macedo, José Mário; Martins-Mendes, Daniela; Pereira, Ana Cláudia; Baylina, PilarPseudomonas aeruginosa (PAO1) is an opportunistic pathogen, lethal in immunocompromised individuals. The clinical management of PAO1 infections still depends deeply on antibiotic therapy. However, this therapy has been alarmingly overpowered by growing bacterial resistance mechanisms over the years. One of these bacterial mechanisms is quorum sensing (QS). QS is involved in the production of biofilm, rhamnolipids and pyocyanin, among other factors. The present study aimed to study the effect of the mutations in the genes of rubredoxin (Rub A1 and Rub A2) and glutaredoxin (GLRx) in the production of virulence traits and susceptibility of PAO1 to the antibiotic ciprofloxacin (CIP) and to infection by a phage cocktail. Rub A1, Rub A2, and GLRx showed a decrease in the expression of genes lasI, lasR, mvfR, and rpsL when compared to the wild type, PAO1. Rub A1 and Rub A2 also showed a decrease in the expression of the gene pqsA, while the mutant GLRx showed an increase of over 200% in expression compared to PAO1. The biofilm produced by the mutants Rub A1, Rub A2, and GLRx increased more than 1.5 times in comparison to PAO1, with statistical significance (p < 0.0001). In the viability assay, the mutant strain Rub A2 was the most susceptible to ciprofloxacin in both concentrations tested (p < 0.0001). The production of proteases increased in the mutant strains when compared to PAO1 (p < 0.05). However, there was a decrease in the production of rhamnolipids and pyocyanins in the mutant strains. In the phage assay, we could perceive a reduction in the growth of the mutant strains when compared to PAO1. Additionally, after the addition of the phages, all the strains showed susceptibility to the phage assay (p < 0.0001), observed in the decrease in the absorbance values. These results may highlight the relevance of the genes Rub A1, Rub A2, and GLRX in the proliferation and treatment of infections with PAO1. Overall, this study gives preliminary insights into how gene expression may be helpful in strategies to overcome antibiotic resistance.