Browsing by Author "Silva, Ana"
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- Assessing Contaminant Uptake and Elimination in Insects: Implications for Sustainable Food Production and Waste ManagementPublication . Cardoso, Diogo; Silva, Ana; Duarte, Regina; Brandão, Pedro; Epifânio, Joana; Azevedo, Abraão; Prodana, Maria; Mostafaie, Amid; Pinto, José; Silva, Patrícia; Coelho, Inês; Rego, Andreia; Alvito, Paula; Brooks, Bryan; Loureiro, SusanaConsidering the global food crisis and the pressing issue of waste generation, sustainable solutions for food demand are crucial. Insects have emerged as a promising protein source for food and feed due to their efficient bioconversion capacity and ability to utilize nonvaluable products. However, ensuring the safety of insects for food and feed is essential. This study aims to comprehensively evaluate the uptake and elimination of contaminants by insects, going beyond conventional measurements of contamination levels. Methodology: The study employed two-phase bioaccumulation studies involving an uptake phase with a contaminated substrate followed by an elimination phase in a clean substrate. Data from these studies were used in toxicokinetic modelling. The objective was to assess the bioaccumulation capacity of mercury (Hg), cadmium (Cd), lead (Pb), arsenic (As), and various polycyclic aromatic compounds (benzo[a] pyrene [B[a]P], benz[a]anthracene [B[a]A], benzo[b]fluoranthene [B[a] F], and crysene [Cry]) in black soldier fly (BSF) larvae (Hermetia illucens). Although high metal bioaccumulation potential (e.g., for Hg, Cd, Pb, As) in edible insects has already been identified as risk, there is a gap regarding hazard assessment of the organic contaminants (e.g., B[a]P, B[a]A, B[a]F, Cry). The findings indicate that when insects were exposed to the maximum allowed levels of metals according to European Union feed regulations, they accumulated contaminant levels unsuitable for feeding other animals. However, after a depuration period, the insects could reduce the contaminant concentrations to comply with the existing legislation. For instance, a 4 to 5 days depuration period was found sufficient for safer consumption of insects exposed to Hg, while a longer period was required for Cd elimination. Interestingly, no significant accumulation of polycyclic aromatic compounds was observed when insects were fed at the maximum allowed levels. Conclusion: These findings have significant implications, particularly when insects are employed as waste converters, where concerns arise regarding contaminants. This study supports the implementation of a depuration period after exposure to waste that may vary depending on the classes of contaminants involved. Toxicokinetics is an adequate tool for the safety assessment of insects as feed and food, but it also defines the conditions that will assure their sustainable use in waste management.
- Effects of physical exercise training in DNA damage and repair - could the difference be in hOGG1 Ser326Cys polymorphism?Publication . Soares, Jorge; Silva, Amélia; Silva, Patrícia; Almeida, Vanessa; Matos, Manuela; TeixeiraGaivão, João Paulo; Mota, Isabel; Silva, AnaAcute physical exercise is associated with increased oxygen consumption, which could result in an increased formation of reactive oxygen species (ROS). ROS can react with several organic structures, namely DNA, causing strand breaks and a variety of modified bases in DNA. Physical exercise training seems to decrease the incidence of oxidative stress-associated diseases, and is considered as a key component of a healthy lifestyle. This is a result of exercise-induced adaptation, which has been associated with the possible increase in antioxidant activity and in oxidative damage repair enzymes, leading to an improved physiological function and enhanced resistance to oxidative stress (Radak et al. 2008). Human 8-oxoguanine DNA glycosylase 1 (hOGG1) is involved in the base excision repair (BER) pathway and encodes an enzyme responsible for removing the most common product of oxidative damage in DNA, 8-hydroxyguanine (8-OH-G). The genetic polymorphism of hOGG1 at codon 326 results in a serine (Ser) to cysteine (Cys) amino acid substitution (Ser326Cys). It has been suggested that the carriers of at least one hOGG1Cys variant allele exhibit lower 8-OH-G excision activity than the wild-type (Wilson et al. 2011). The aim of this study was to investigate the possible influence of hOGG1 Ser326Cys polymorphism on DNA damage and repair activity in response to 16 weeks of combined physical exercise training, in thirty healthy Caucasian men. Comet assay was carried out using peripheral blood lymphocytes and enabled the evaluation of DNA damage, both strand breaks and FPG-sensitive sites, and DNA repair activity. Genotypes were determined by PCR-RFLP analysis. The subjects with Ser/Ser genotype were considered as wild-type group (n=20), Ser/Cys and Cys/Cys genotype were analyzed together as mutant group (n=10). Regarding differences between pre and post-training in the wild-type group, the results showed a significant decrease in DNA strand breaks (DNA SBs) (p=0.002) and also in FPG-sensitive sites (p=0.017). No significant differences were observed in weight (p=0.389) and in lipid peroxidation (MDA) (p=0.102). A significant increase in total antioxidant capacity (evaluated by ABTS) was observed (p=0.010). Regarding mutant group, the results showed a significant decrease in DNA SBs (p=0.008) and in weight (p=0.028). No significant differences were observed in FPG-sensitive sites (p=0.916), in ABTS (p=0.074) and in MDA (p=0.086). No significant changes in DNA repair activity were observed in both genotype groups. This preliminary study suggests the possibility of different responses in DNA damage to physical exercise training, considering the hOGG1 Ser326Cys polymorphism.
- Metabolic Diseases Masquerading As Primary Progressive Multiple SclerosisPublication . Nogueira, Célia; Vilarinho, Laura; Ribeiro, Diogo; Alves, Sandra; Vieira, Luís; Sá, Maria José; Macário, Maria do Carmo; Silva, Ana; Sá, JoãoObjectives: The overall aim of our research project is to develop a Next Generation Sequencing strategy to identify metabolic disorders in patients with a presumptive diagnosis of primary progressive MS.
- Metabolic Diseases: a differential diagnosis of primary progressive multiple sclerosisPublication . Nogueira, Célia; Vilarinho, Laura; Ribeiro, Diogo; Sá, Maria José; Macário, Maria do Carmo; Silva, AnaObjectives: The overall aim of our research project is to develop a Next Generation Sequencing strategy to identify metabolic disorders in 104 patients with a presumptive diagnosis of primary progressive MS.