CBQF - Documentos de Conferências / Conference Objects
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- Decellularized small intestine for burn wound treatment: a tissue engineering paradigm shift?Publication . Silva, Inês V.; Rosadas, Marta; Rodrigues, Ilda; Sousa, Clara; Ribeiro, Viviana; Costa, Raquel; Moroni, Lorenzo; Oliveira, Ana L.Introduction: Burn injuries are a significant global health issue, causing approximately 11 million injuries and 180,000 fatalities each year (1). Beyond physical trauma, burn injuries lead to complications such as infections and sepsis. Burn scars can also diminish quality of life by affecting joint mobility and daily activities (2,3). Conventional dressings and autografts have limitations, necessitating novel treatment strategies (4). Decellularized xenografts, particularly from porcine small intestine (SI), offer a promising alternative due to their content of growth factors and structural proteins essential for wound healing (5,6). Preserving these bioactive molecules while ensuring cost-effectiveness requires carefully designed decellularization processes. This study investigates a new decellularization protocol aimed at creating a safe and highly preserved extracellular matrix (ECM) from porcine SI for optimal functional wound dressing. Conclusion: Our results indicate that the protocol implemented effectively preserves essential ECM components and structure while removing cellular contaminants. The material demonstrates anisotropic preserved mechanical properties, adequate swelling capacity, and WTVR similar to skin. The treated samples present biocompatibility, as they do not hinder human fibroblast metabolic activity. This innovative strategy presents a promising approach to produce preserved ECM that could be further process to become a solution for wound healing and tissue regeneration, particularly in challenging cases like burns. Future research will focus on enhancing its antibacterial and anti-inflammatory properties to further improve its efficacy as a dressing for challenging wounds.
- Assessing the persister state in Listeria monocytogenes in response to gentamicin, benzalkonium chloride and bacteriocin SB83Publication . Sousa, Mariana; Azevedo, Mónica; Magalhães, Rui; Almeida, Gonçalo; Teixeira, PaulaIntroduction: In the context of food safety, persister cells are a public health concern since these may contribute to the persistence and survival of bacteria in food processing environments. Listeria monocytogenes persisters are described as a subpopulation of growth-arrested cells that possess non-heritable, temporary tolerance to lethal doses of antibiotics (e.g., gentamicin) and can revert to an active state under favorable conditions. This dormancy state can be studied through biphasic killing curves – initial drop of susceptible cells followed by a plateau of persisters in response to continuous antibiotic exposure or to its increasing concentration. Nonewithstanding, gaps still exist to understand whether stresses present in the food-producing sector, such as disinfectants and bacteriocins, can also contribute to the formation of persisters. Conclusion: Neither bacteriocin SB83 nor BAC were able to induce the persisters state.The gentamicin exposure is still the only validated approach to achieve the persister dormancy state. Further studies must focus in understanding the tolerance profile of persister cells to food facilities stresses.
- CATALYSE Action: collaborative networks transforming food safety innovative solutionsPublication . Sarquis, Agustina; Bourdichon, François; Fonseca, Diana; Teixeira, Paula; Cortez, João; Bassi, Daniela
- Cutting-edge hybrid dressings: combining silk medical textiles and decellularized biological tissue for advanced burn wound carePublication . Sousa, Teresa; Vale, Inês; Rosadas, Marta; Silva, Inês V.; Ribeiro, Viviana P.; Oliveira, Ana L.Aim: Burns affect 11 million people globally each year, with 180,000 fatalities [1]. This study investigates a multilayer burn dressing combining silk fibroin (SF) fabric with highly- preserved decellularized porcine small intestine (dPSI) to support tissue regeneration and wound integration [2]. A silk sericin (SS) hydrogel is included as interface for structural integrity and anti-inflammatory benefits, enhancing the hybrid dressing’s biological performance. Methods: An innovative decellularization protocol was proposed to obtain dPSI, maintaining submucosa, serosa, and muscle layers, using cycles of decellularizing agents (SDS, SDC, DMSO), washing agents (upH₂O, PBS), and sterilization (PAA/ethanol). The serosa and submucosa of dPSI were integrated with SF-based textiles using HRP- crosslinked SS hydrogels. Decellularization and integrity were assessed via DNA quantification and histology, while hybrid dressings’ morphology and mechanics were evaluated by SEM and tensile tests. Degradation profile was tested in simulated wound fluid, and biological performance was assessed by culturing human dermal fibroblasts (hDFs) on the submucosa layer up to 10 days. Results: The dPSI was successfully achieved (<50 ng/mg dsDNA). SEM images confirmed the full integration of the dPSI with SF-based textiles, especially when serosa faced the textile. The presence of the textile structure resulted in an enhancement of the mechanical strength. dPSI was able to degrade first in the multilayer dressing, and hDFs adhered and proliferated on the submucosa over 10 days, supporting hybrid structural integrity. Conclusions: This study is pioneer in confirming promising results for the first multilayer hybrid dressing combining medical textiles and dPSI for burn wound applications.
- The Catalyse Project: a community of practice to foster food safety innovationsPublication . Fonseca, Diana R.; Cortez, João; Teixeira, Paula
- Extraction of bioactive compounds from plants as promising agentes against SARS-CoV-2Publication . Pedrosa, Mariana C.; Rodrigues, Cláudia; Heleno, Sandrina; Carocho, Márcio; Abreu, Rui M. V.; Ribeiro, Tânia; Machado, Manuela; Pinto, Miguel Marques; Simas, Pedro; Pintado, Manuela; Barros, LillianBackground: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a pathogenic virus with high transmissibility and infectivity, which began to spread across the globe in late 2019, which soon became the COVID-19 pandemic, causing social and economic impacts. In response to this situation, the scientific community started the development of effective substances against this virus. Bioactive molecules present in plants, mainly phenolic compounds, are promising alternatives to combat pathological disorders. Therefore, the objective of this work was to use the aqueous extract of a mountain plant as an antiviral substance to neutralize COVID-19. Materials/Methods: The mountain plant extract was obtained by dynamic maceration in water for 1 hour (twice). After obtaining the extracts, they were evaluated for their phenolic profile by high performance liquid chromatography coupled to a diode array detector and a mass spectrometer detector (HPLC-DAD-MS). Cytotoxicity was determined by the sulphorhodamine B assay in Vero cells, as well as the evaluation of the antiviral activity. Results: Regarding the phenolic profile, the main compounds found were trigalloyl-HHDPglucoside; pentagalloyl glucose, quercetin 3-0-glucuronide and quercetin O-hexoside. The GI50 (concentration able to inhibit 50% of cell proliferation) and the MNCC (maximum concentration without toxicity) were between 100 and 180.3 µg/rnL and between 85 and 120 µg/rnL, respectively. The MNCC value was obtained considering the concentration that allowed 90% of cell proliferation of Vero cells. In relation to the viral activity screening, the results achieved for the viral titre were between 5000 and 9000 PFU/mL, while for the antiviral activity ranged between 0.5 and 3.0 Mv, being the percentage of reduction in a range of 85-95 %. Conclusion: The mountain plant extracts showed in its composition bioactive compounds and consistent results of antiviral activity. Moreover, it presents itself as a potential substance for protection applications against the COVID-19 virus. However, further studies in specific products are required for validation and implementation.
- European seabass response to air exposure: impact of dietary inclusion of bioactive blood hydrolysatesPublication . Resende, Daniela; Pereira, Ricardo; Velasco, Cristina; Domínguez, David; Pereira, Miguel; Pereira, Carlos; Marques, Bianca; Rocha, Cristina; Lima, Rui Costa; Pintado, Manuela; Valente, Luísa M. P.In aquaculture farms, fish are subjected to stress situations, which induce oxidative stress through an imbalance between the generation of reactive oxygen species (ROS) and the scavenging activity of antioxidants. Diet supplementation with functional ingredients to modulate oxidative stress after air exposure was investigated, using bioactive peptides from swine blood hydrolysates (BH), within a circular economy context. Three swine BH were obtained by autohydrolysis (AH) or enzymatically. The enzymatically produced BH were further submitted to a micro- (MF) or nanofiltration (NF). Five isolipidic and isoproteic diets for European seabass were developed: a fishmeal (FM) based diet (positive control, PC), a commercial-based diet where 50% of FM was replaced by vegetable proteins (negative control, NC) and three diets where 3% of each BH was added to the NC. Diets were assigned to triplicate groups of 71 European seabass juveniles (initial weight 12.3 ± 1.4 g), and fed to apparent satiation in a recirculating saltwater system. After 12 weeks, 9 fish per treatment were either immediately sampled or air-exposed for 1 minute and let to recover for 6 hours prior to sampling, in which plasma and liver were collected. Plasmatic cortisol and lactate were elevated for all diets after the air exposure, without differences among diets. Glucose levels were unaffected by diet or stress. Regarding liver oxidative stress markers, lipid peroxidation (LPO) tended to increase after air exposure. Considering the non-stressed fish, MF diet led to the lowest LPO, being significantly lower than the AH, and similar to the remaining diets. Protein oxidation decreased in stressed fish, but did not differ among diets. Liver catalase was significantly lower in NC, NF and AH groups compared to PC and increased after stress. Superoxide dismutase activity was lower for AH and PC diets than for the MF, and it was reduced in stressed fish. The stress response triggered by air exposure involved increased cortisol levels, followed by an increment in plasma lactate. However, none of the BH improved plasma stress response. The stress challenge increased liver LPO through ROS accumulation under oxidative stress. Carbonyls decreased post-stress, likely due to a feedback interaction with the LPO radicals, which reduced protein oxidation. The NF, composed of smaller peptides than the other BH, may modulate European seabass antioxidant defences by lowering catalase levels without increasing LPO, suggesting it could provide exogenous antioxidants to counteract ROS-induced oxidative stress.
- Effect of the dietary inclusion of blood hydrolysates on European seabass response to stressPublication . Resende, Daniela; Pereira, Ricardo; Velasco, Cristina; Domínguez, David; Pereira, Miguel; Pereira, Carlos; Marques, Bianca; Rocha, Cristina; Pintado, Manuela; Valente, Luísa M. P.
- Metagenomic assessment of the microbial diversity of swine carcassesPublication . Carvalho, Marta; Moura-Alves, Márcio; Saraiva, Cristina; Esteves, Alexandra; Ribeiro, Deise; Leonardo, Inês Carvalho; Gaspar, Frédéric Bustos; Crespo, Maria Teresa Barreto; Teixeira, PaulaContamination, cross-contamination, or carcass recontamination can mainly occur along the slaughtering processes due to contact between animals during their transportation, steps of slaughter carcass preparation, slaughterhouse environment, clothing, and poor slaughter and hygiene practices [1]. Evaluating the microbiological profile is important to verify hygiene conditions during the slaughter processes and ensure the food safety of the final product [2]. The purpose of this study was to characterize the microbial community of swine carcasses and environmental samples - knives and drains - using a metagenomic approach. Gauze swabs were used to collect samples from drains and from five animals before and after evisceration, and water from the knives sterilizer was collected in sterile tubes before and after eviscerations. Samples were prepared for Illumina Sequencing by 16S rRNA gene amplification of the bacterial community. All 16S rRNA data were analysed with Kraken v1 using the pre-built MiniKraken 8Gb database (https://ccb.jhu.edu/software/kraken/) with default parameters. Twenty-five genera with abundance above 1% were found. The most abundant genus on carcasses was Anoxybacillus (52% of the total microbiome) and on environmental samples Oenococcus (15%). Enterobacteriaceae were detected in 13 collected points (prevalence ranging from 0.001% to 0.02%), with different genera found: Citrobacter (18.0%), Klebsiella (14.0%), Erwinia (12.1%), Enterobacter (9.99%), Trabulsiella (5.99%), Providencia (4.0%), Serratia (4.0%), Salmonella (4.0%) and Morganella (1.99%). It is important to highlight that Salmonella spp. was found in only two samples, one from the carcass and the other from the drain sampled on the same day. Other genera of interest in food microbiology were also detected, namely, Pseudomonas, Lactobacillus, Campylobacter, Clostridium, Bacillus, Staphylococcus, and Lactococcus. Such diversity suggests possible interventions to extend shelf life hampered by the microbial consortia with pork products. Otherwise, it may be useful for developing microbial traceability to a slaughterhouse.
- Nitrate reducing starter culture and natural nitrate sources as a "clean label" alternative in meat productsPublication . Carvalho, Teresa; Oliveira, Mónica; Komora, Norton; Teixeira, PaulaIntroduction and objectives: Clean label products have been introduced in the market with the goal of ensuring product safety having in sight the protection of the environment and public health. This study aimed to assess a clean label alternative to nitrite addition in cooked ham manufacturing by exploiting natural plant sources of nitrate as the substrate for a nitrate reductase- producing starter culture. Methods: Cooked hams were prepared at a laboratory scale using minced pork leg and water, salt, sodium tripolyphosphate and carrageenan. Results: All the produced hams had a characteristic odor. The main difference observed was the color: A typical reddish-pink color formation was observed in hams with the starter culture combined with fresh spinach (K) or radish (M) cooking water; When combined with beetroot (I) and paprika (J), the starter culture was unable to produce the desirable color; Regarding texture, hams produced with spinach cooking water in combination with the starter culture (K) and the model matrix (A) were only similar for the chewiness parameters analyzed (p=0.242), being both products microbiologically stable during at least 10 days of storage at 4 °C. Conclusion and relevance: Although preliminary, these results highlight the feasibility of combining spinach cooking water and a nitrate reductase-producing starter culture as a promising clean label solution to the addition of chemical nitrite in cooked ham production.