RUN
Repositório Institucional da Universidade NOVA de Lisboa
Entradas recentes
Influence of commensal bacteria on the proteolytic and antigenic profiles of INFOGEST-like digested wheat gliadin
Publication . Pereira-Costa, Flávio; Domingues, Vanessa S.; Roque, Ana; Almeida, Zaida L.; Cruz, Pedro F.; Cordeiro, Rachel; Trindade, Daniela; Moura, Carla; Melo, Joana B.; Pereira, Sónia G.; Vaz, Daniela C.; DCV - Departamento de Ciências da Vida; Frontiers Research Foundation
Introduction – Celiac disease (CeD) is a chronic autoimmune enteropathy developed by genetically predisposed individuals when exposed to gluten. Gluten gliadins, along with gut microbiota, may influence CeD onset and progression through mechanisms that remain unclear. Methods – Gliadin-degrading bacterial isolates obtained from CeD patients, and their 1st-degree relatives’ stool and blood were identified (Bacillus tropicus, Enterococcus faecalis, Micrococcus sp., Cronobacter sakazakii, Pseudomonas aeruginosa, and Serratia marcescens) and used in an INFOGEST-like protocol to simulate gliadin digestion after 4 h (digested gliadin, d-gliadin). The d-gliadin digesta were analyzed by fast protein liquid chromatography (FPLC), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), fluorescence spectroscopy, and polyclonal and monoclonal (R5 and G12) enzyme-linked immunosorbent assays (ELISA). Results and discussion – In the absence of the bacterial isolates, gliadin is poorly digested and self-assembles within 1 day into intermediate and large protein oligomers/aggregates, enriched in β-sheet structure (FTIR amide I band between 1, 600 and 1, 700 cm−1) and able to bind thioflavin T and Congo red. Conversely, in the presence of the bacterial isolates, gliadin is further digested, leading to an increase in protein fragments. After 4 h, the P. aeruginosa, C. sakazakii, and B. tropicus d-gliadin digesta presented a mixture of d-gliadin peptides and aggregates that showed higher antigenicity (associated with the exposure of the 5-amino acid QQPFP and 6-amino acid QPQLPY epitopes, present in the 25-mer and 33-mer, respectively) than control digestions (without bacteria), while E. faecalis led to lower antigenicity. In turn, within 24 h of incubation, all bacterial isolates led to the formation of undigested material with lower antigenicity, either due to fewer 33-mers and 25-mers in solution, or to fragment aggregation into amorphous material, not exposing antigenic sequences. Hence, intestinal flora may enhance or diminish the antigenicity of gliadin, thereby modulating the immunogenic response to gliadin/gluten.
Effect of Urolithin A on Bovine Sperm Capacitation and In Vitro Fertilization
Publication . Jorge, Manuela; Ferreira, Filipa C.; Marques, Carla C.; Batista, Maria C.; Oliveira, Paulo J.; Lidon, F.; Duarte, Sofia C.; Teixeira, José; Pereira, Rosa M.L.N.; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; MDPI - Multidisciplinary Digital Publishing Institute
Reactive oxygen species (ROS) play a critical role in the functional competence of sperm cells. Conversely, excessive generation of ROS can impair sperm function, including their fertilization ability. Urolithin A (UA), a gut bacteria-derived metabolite produced from the transformation of ellagitannins, with anti-aging and antioxidant properties, was investigated for the first time in bovine sperm cells in the present study. Firstly, different doses of UA (0, 1, and 10 μM; 8–16 sessions) were used during the capacitation process of frozen-thawed bovine sperm. Sperm motility was assessed using optical microscopy and CASA. Sperm vitality (eosin-nigrosin), ROS, and ATP levels, as well as mitochondrial membrane potential (JC1) and oxygen consumption were evaluated. A second experiment to test the effect of different doses of UA (0, 1, and 10 μM; 9 sessions) in both the capacitation medium, as above, and the fertilization medium, was also implemented. The embryonic development and quality were evaluated. UA, at a concentration of 1 μM, significantly improved sperm movement quality (p < 0.03). There was a trend towards an increase in the oxygen consumption rate (OCR) of capacitated sperm with 1 μM and 10 μM UA supplementation. Moreover, an increase in ATP levels (p < 0.01) was observed, accompanied by a reduction in ROS levels at the higher UA concentration. These results suggest that UA may enhance spermatozoa mitochondrial function, modifying their metabolic activity while reducing the oxidative stress. Also, the number of produced embryos appears to be positively affected by UA supplementation, although differences between the bulls may have mitigated this effect. In conclusion, presented results further support previous findings indicating the potential therapeutic value of UA for addressing reproductive sub/infertility problems and improving ART outcomes. In addition, our results also reinforce the important bull effect on ART and that male sperm bioenergetic parameters should be used to predict spermatozoa functionality and developmental potential.
Microbiota Identification of the Artisanal Fermented Beverages Boj and Suchiles Made in Guatemala
Publication . Ronquillo Blau, Claudia; Hutzler, Mathias; Zarnkow, Martin; Eizaguirre, Juan; Escoto, Diego; Sampaio, Jose Paulo; Jacob, Fritz; UCIBIO - Applied Molecular Biosciences Unit; DCV - Departamento de Ciências da Vida; Taylor & Francis
Microorganisms were isolated and identified from the artisanal fermented beverages Boj and Suchiles made in Guatemala. The identification of these microorganisms contributes to the character of these local beverages. Bacteria and yeasts were first isolated in specific media and then analyzed using rDNA sequencing and MALDI-TOF MS. The following species were identified in Boj: Saccharomyces cerevisiae, Lacticaseibacillus casei, Lc. paracasei, Lentilactobacillus diolivorans, Schleiferilactobacillus harbinensis, Staphylococcus epidermidis, and Paenibacillus sp., and in Suchiles, the isolated strains were identified as S. cerevisiae, Saccharomycodes ludwigii, Lc. paracasei, Pichia cactophila, Dekkera bruxellensis, D. anomala, Bacillus clausii, B. safensis, Ln. diolorivans, Sch. harbinensis, Ln. parafarraginis, and Acetobacter aceti. The information provided in this study contributes to a deeper understanding of the artisanal beverages Boj and Suchiles. It could serve as a supporting step to the controlled reproduction of these beverages.
Continuous data assimilation for a class of non-Newtonian fluids of differential type in 2d and 3d
Publication . Nouira, Raya; Kinra, Kush; Cipriano, Fernanda; CMA - Centro de Matemática e Aplicações; DM - Departamento de Matemática; Academic Press Inc | Elsevier Science
This study addresses a class of non-Newtonian fluids governed by third-grade fluid equations, which exhibit complex and highly non-linear dynamics. To enhance the model's accuracy and state prediction in both two- and three- dimensional settings, particularly in the absence of initial conditions, we employ continuous data assimilation techniques. By incorporating velocity observational measurements - via general interpolant operators - into fluid dynamics, we derive an approximation algorithm. We first prove that the latter is well-posed, and then demonstrate that it ensures exponential stabilization of the state model as time goes to ∞. As a consequence, we show that the reconstructed state predicts the true solution within a prescribed level of accuracy over a finite time interval.
The early origin of Iguanodontia
Publication . Rotatori, Filippo Maria; Chiarenza, Alfio Alessandro; Fanti, Federico; Moreno-Azanza, Miguel; DCT - Departamento de Ciências da Terra; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; John Wiley and Sons Inc.
Iguanodontia (Dinosauria, Ornithischia) is a speciose group of herbivorous dinosaurs that include the famous genus Iguanodon, one of foundational members of the clade Dinosauria. Despite their very long history of research, several aspects of their systematic relationships and their evolutionary history remain somewhat nebulous. There is currently a lack of consensus between different phylogenetic matrices due mainly to: (1) undersampling of postcranial characters; and (2) the absence of several key taxa. We assembled a data matrix from pre-existing datasets, integrating our observations on several overlooked species (mainly from Europe) and extensively sampling cranial and postcranial characters, thereby creating one of the most complete datasets for iguanodontian dinosaurs to date. We performed a series of phylogenetic analyses, employing maximum parsimony and Bayesian inference, and an historical biogeographic analysis. Overall congruent topologies between the two methods recovered, for the first time, a new clade of high-sailed styracosternans here named Ouranosauria. We ran different Bayesian inference analyses, employing morphoclock and fossilized birth–death models. Some of the tip-dated analyses, indicated an Early to Middle Jurassic origin of Iguanodontia during a palaeoclimatically (hyperthermal) and palaeogeographically (continental fragmentation) dynamic context. According to this scenario, the Iguanodontian major radiation could be tracked back to the Pliensbachian–Toarcian, pre-dating by 16 million years the first ichnological evidence attributed to this clade. Furthermore, the diversification of all the major clades occurred by the Late Jurassic, then experienced local extinction events in different areas during the Early Cretaceous. Prior to the Jurassic–Cretaceous transition, iguanodontians spread globally.