Browsing by Author "Almeida, D."
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- Akkermansia muciniphila antimicrobial susceptibility profilePublication . Barbosa, J. C.; Machado, D.; Almeida, D.; Andrade, J. C.; Freitas, A. C.; Gomes, A. M.
- Effect of pH upon viability of probiotic strains when in contact with fruit pulpsPublication . Rodrigues, C.; Sousa, S.; Pinto, A.; Brandão, T.; Silva, J.; Pintado, M.; Silva, C.; Morais, A.; Teixeira, P.; Gomes, A.; Almeida, D.In recent years many probiotic-containing products have been developed, being dairy and dried products the main vehicles for probiotic intake. Fruit juices have also been studied, with less good results, probably due to their low pH values, as well as to the presence of other components, adverse to the survival of the probiotic strains. In order to pinpoint possible reasons therefore, in this study we tried to evaluate the effect of the fruit pulp pH upon the survival of Lactobacillus acidophilus LA-5 and Bifidobacterium animalis BB-12. Two fruit pulps, with different pH values, were used, namely lemon (pH=2.5) and avocado (pH=6.5), and their pH was adjusted (to 2.5, 4.5 and 6.5), in order to access the effect upon probiotic survival over one week storage. Viability was evaluated at 0, 3 and 7 days. Results showed that, although the pH value is indeed important, it is not the only reason for low viability of probiotics when incorporated in fruit pulps. Viability was, as expected, the highest when the pulps had a pH value of 6.5. At 4.5, avocado still had considerable viable cell numbers after one week contact with the pulp, while for lemon, at the same pH, no probiotics were detected after 3 days. At 2.5, for both pulps, no viable cells were detected after only 3 days. These results indicate that, although pH is important, other constituents of the fruits are also responsible for the degree of survival of probiotics in fruit matrices.
- Formulation strategies for enhancing growth of akkermansia muciniphila and its survival through lyophilisation and storage at air ambientPublication . Freitas, A.; Almeida, D.; Machado, D.; Mendo, S.; Gomes, A.Gut bacterium Akkermansia muciniphila has been recognized as a new potential probiotic due to promising outcomes in the prevention and treatment of several human diseases. However, despite its multiple beneficial effects, its viability is compromised by the presence of oxygen. This has so far precluded its application namely in the development of nutraceutical/therapeutic formulations. In order to enhance growth of A. muciniphila and its survival through lyophilisation and storage at air ambient, formulation strategies are presented based on use of prebiotic compounds, antioxidants and cryoprotectants. According to our best knowledge, there is no information regarding lyophilisation procedures involving A. muciniphila as well as its subsequent storage at ambient air.
- Investigating the susceptibility of the next generation probiotic faecalibacterium prausnitzii under stress conditionsPublication . Machado, D.; Domingos, M.; Almeida, D.; Barbosa, J. C.; Andrade, J. C.; Freitas, A. C.; Gomes, A. M.
- Potential of Akkermansia muciniphila DSM 22959 and Faecalibacterium duncaniae DSM 17677 as live biotherapeutics for intestinal infectionsPublication . Machado, D.; Vedor, R.; Fonseca, M.; Bento, M.; Barbosa, J. C.; Almeida, D.; Andrade, J. C.; Gomes, A. M.
- Potential of Akkermansia muciniphila DSM 22959 and Faecalibacterium duncaniae DSM 17677 as live biotherapeutics for intestinal infectionsPublication . Machado, D.; Vedor, R.; Fonseca, M.; Bento, M.; Barbosa, J. C.; Almeida, D.; Andrade, J. C.; Gomes, A. M.Introduction: In the last years, human intestinal bacteria, including Akkermansia muciniphila and Faecalibacterium duncaniae, have emerged as next generation probiotics to be incorporated in foods or delivered in pharmaceutical forms. Despite their multiple health benefits, the inhibitory properties of these probiotics against pathogenic colonization remain poorly studied, mainly due to difficulties in their culture and handling, as consequence of their anaerobic nature. Objective: Evaluate the potential of type strains A. muciniphila DSM 22959 and F. duncaniae DSM 17677 to prevent pathogenic colonization. Methodology: In vitro assays aimed to determine the following properties of these intestinal commensals were performed: i) auto-aggregation and co-aggregation with pathogens, using a spectrophotometric method; ii) biofilm-forming ability, measured through crystal violet staining method; and iii) antimicrobial activity of their supernatants via agar well diffusion. Complementarily, the putative production of antimicrobial compounds of proteinaceous nature was predicted using in silico approaches, namely through the application of BAGEL4 and antiSMASH bioinformatic tools. Main findings: Both type strains were able to auto-aggregate, and co-aggregate with pathogens, but in different extents. Overall, higher auto- and co-aggregation percentages were verified for F. duncaniae DSM 17677. Also, F. duncaniae DSM 17677 exhibited a moderate ability to form biofilms, while A. muciniphila DSM 22959 was classified as weak producer. Phenotypically, no antimicrobial activity of the type strains supernatants was observed against nine pathogens; a finding that was further corroborated by the in silico analysis. Conclusion: Our study revealed that both A. muciniphila DSM 22959 and F. duncaniae DSM 17677 presented key features for their persistence in the intestinal ecosystem and possible prevention of pathogenic colonization and subsequent infection. Therefore, these findings highlight the potential of these human intestinal commensals, mainly F. duncaniae DSM 17677, to be used successfully as live biotherapeutic agents against intestinal infections.
- Technology update on greenhouse horticulture in Portugal.Publication . Costa, J. M.; Reis, M.; Almeida, D.; Carvalho, Susana; Palha, M G.; Vargues, A.; Passarinho, J.; Ferreira, M. E.