Browsing by Author "Guedes, Carla"
Now showing 1 - 8 of 8
Results Per Page
Sort Options
- From the gut to the brain: Is microbiota a new paradigm in Parkinson’s disease treatment?Publication . Vilela, Cristiana; Araújo, Bruna; Guedes, Carla; Silva, Rita Caridade; Macedo, Joana Martins; Teixeira, Catarina; Gomes, Eduardo; Prudêncio, Cristina; Vieira, Mónica; Teixeira, Fábio G.Parkinson’s disease (PD) is recognized as the second most prevalent primary chronic neurodegenerative disorder of the central nervous system. Clinically, PD is characterized as a movement disorder, exhibiting an incidence and mortality rate that is increasing faster than any other neurological condition. In recent years, there has been a growing interest concerning the role of the gut microbiota in the etiology and pathophysiology of PD. The establishment of a brain–gut microbiota axis is now real, with evidence denoting a bidirectional communication between the brain and the gut microbiota through metabolic, immune, neuronal, and endocrine mechanisms and pathways. Among these, the vagus nerve represents the most direct form of communication between the brain and the gut. Given the potential interactions between bacteria and drugs, it has been observed that the therapies for PD can have an impact on the composition of the microbiota. Therefore, in the scope of the present review, we will discuss the current understanding of gut microbiota on PD and whether this may be a new paradigm for treating this devastating disease.
- Ionizing radiation from radiopharmaceuticals and the human gut microbiota: An ex vivo approachPublication . Fernandes, Ana; Oliveira, Ana; Guedes, Carla; Fernandes, Rúben; Soares, Raquel; Barata, PedroThis study aimed to determine the effect of three widely used radiopharmaceuticals with intestinal excretion on selected relevant bacteria that are part of the human gut microbiota, using an ex vivo approach. Fecal samples obtained from healthy volunteers were analyzed. Each sample was divided into four smaller aliquots. One served as the non-irradiated control. The other three were homogenized with three radiopharmaceutical solutions ([131I]NaI, [99mTc]NaTcO4, and [223Ra]RaCl2). Relative quantification of each taxa was determined by the 2−ΔΔC method, using the ribosomal gene 16S as an internal control (primers 534/385). Twelve fecal samples were analysed: three controls and nine irradiated. Our experiment showed fold changes in all analyzed taxa with all radiopharmaceuticals, but results were more significant with I-131, ranging from 1.87–83.58; whereas no relevant differences were found with Tc-99m and Ra-223, ranging from 0.98–1.58 and 0.83–1.97, respectively. This study corroborates limited existing research on how ionizing radiation changes the gut microbiota composition, providing novel data regarding the ex vivo effect of radiopharmaceuticals. Our findings justify the need for future larger scale projects.
- New CTX-M group conferring β-Lactam resistance: A compendium of phylogenetic insights from biochemical, molecular, and structural biologyPublication . Mendonça, Jacinta; Guedes, Carla; Silva, Carina; Sá, Sara; Oliveira, Marco; Accioly, Gustavo; Baylina, Pilar; Barata, Pedro; Pereira, Cláudia; Fernandes, RubenThe production of extended-spectrum β-lactamases (ESBLs) is the main defense mechanism found in Gram negative bacteria. Among all the ESBLs, the CTX-M enzymes appear as the most efficient in terms of dissemination in different epidemiological contexts. CTX-M enzymes exhibit a striking plasticity, with a large number of allelic variants distributed in several sublineages, which can be associated with functional heterogeneity of clinical relevance. This observational analytical study provides an update of this family, currently with more than 200 variants described, from a phylogenetic, molecular, and structural point of view through homology in amino acid sequences. Our data, combined with described literature, provide phylogenetic and structural evidence of a new group. Thus, herein, we propose six groups among CTX-M enzymes: the already stablished CTX-M-1, CTX-M-2, CTX-M-8, CTX-M-9, and CTX-M-25 clusters, as well as CTX-M-151 as the new cluster.
- 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.
- Phylogenetic Insights of β-lactam resistance of the CTX-M familyPublication . Coelho, Pedro Barata; Mendonça, Jacinta; Silva, Carina; Baylina, Pilar; Fernandes, Ruben; Guedes, CarlaBacterial resistance is a major public health concern, particularly against β-lactam antibiotics, one of the most widely used antibacterial drugs. The production of extended-spectrum β-lactamases (ESBLs) is the main defense mechanism found in Gram negative bacteria. Among all the ESBLs, the CTX-M enzymes appear as the most efficient in terms of diffusion in different epidemiological contexts, outnumbering the others. Originated in chromosomal genes of Klyvera spp., the blaCTX-M genes have become associated with mobile genetic elements, such as plasmids, that have mediated inter-replication and dissemination. CTX-M enzymes exhibit a striking plasticity, with a large number of allelic variants belonging to several sub-lineages, which can be associated with functional heterogeneity of clinical relevance. This observational analytical study provides an update of this family, currently with more than 200 variants described, from a phylogenetic, molecular and structural point of view through homology in amino acid sequences. There are currently 6 defined clusters (CTX-M-1, CTX-M-2, CTX-M-8, CTX-M-9, CTX-M-25 and CTX-M-151), with the domains CTX -M-1 and CTX-M-9 presenting subgroups, composed mainly of variants identified as hybrids between them (particularly between CTX-M-14 and CTX-M-15).
- The history and applications of phage therapy in Pseudomonas aeruginosaPublication . Silva, Carina; Sá, Sara; Guedes, Carla; Oliveira, Carla; Lima, Cláudio; Oliveira, Marco; Mendes, João; Novais, Gonçalo; Baylina, Pilar; Fernandes, RúbenThe Pseudomonas aeruginosa is one of the bacteria that cause serious infections due to resistance to many antibiotics can be fatal in severe cases. Antimicrobial resistance is a global public health concern. To solve this problem, interest in phage therapy has revived; some studies are being developed to try to prove the effectiveness of this therapy. Thus, in this opinion article, several historical aspects are addressed as well some applications of phage therapy against P. aeruginosa.
- The influence of adipocyte secretome on selected metabolic fingerprints of breast cancer cell lines representing the four major breast cancer subtypesPublication . Luís, Carla; Guerra-Carvalho, Bárbara; Braga, Patrícia C.; Guedes, Carla; Patrício, Emília; Alves, Marco G.; Fernandes, Ruben; Soares, RaquelMolecular subtype (MS) is one of the most used classifications of breast cancer (BC). Four MSs are widely accepted according to receptor expression of estrogen, progesterone, and HER2. The impact of adipose tissue on BC MS metabolic impairment is still unclear. The present work aims to elucidate the metabolic alterations in breast cancer cell lines representing different MSs subjected to adipocyte associated factors. Preadipocytes isolated from human subcutaneous adipose tissue were differentiated into mature adipocytes. MS representative cell lines were exposed to mature adipocyte secretome. Extracellular medium was collected for metabolomics and RNA was extracted to evaluate enzymatic expression by RT-PCR. Adipocyte secretome exposure resulted in a decrease in the Warburg effect rate and an increase in cholesterol release. HER2+ cell lines (BT-474 and SK-BR-3) exhibited a similar metabolic pattern, in contrast to luminal A (MCF-7) and triple negative (TN) (MDA-MB-231), both presenting identical metabolisms. Anaplerosis was found in luminal A and TN representative cells, whereas cataplerotic reactions were likely to occur in HER2+ cell lines. Our results indicate that adipocyte secretome affects the central metabolism distinctly in each BC MS representative cell line.
- 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.