Browsing by Author "Teixeira, Paula"
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- Evaluation of minimum inhibition concentrations of plant against environmental fungi and dermatophytesPublication . Afonso, Tiago B.; Melo, Adma N.F.; Carvalho, Marta; Ribeiro, Tânia; Pinto, Miguel M.; Barros, Lillian; Carocho, Márcio; Tavaria, Freni K.; Teixeira, Paula; Pintado, ManuelaThe outbreak of COVID-19 disease eaused by SARS-CoV-2 has led the seientifie eompmnity to seareh for new alternatives to help eontrol the virus. In this context, the use of face masks has been reeommended as a preventive measure against the spread of SARS-CoV-2. The application of antimierobial agents in the tissues used to produee masks would be an additional hurdle on the prevention of other respiratory infeetions and seeondary fungaI infeetions that oeeur from touehing eontaminated masks. In this eontext, impregnation of the fabries with plant derived extraets is an attraetive approaeh sinee they are potential1y safe, free of adverse side effeets, and powerful antimierobials. The objeetive of this work was to study fifteen plant extraets to seleet the most effieient against environmental fungi and some dermatophytes. MaterialslMethods: The minimum inhibitory eoneentration (MIC) of eaeh plant derived extraet was determined by broth mierodilution in 96-wells mierotiter plates. Coneentrations ranging from 50 mg/mL to 1.5625 mg/mL were tested against lhe different fungi. Briefly, 100 mL of a 105 spores/mL solution were added to 100 mL of eaeh extraet eoneentration. Afier 48 h, 10 mL of eaeh well were plated onto Sabouraud Dextrose Agar. Cultivation was earried out at 25 °C for 3 days for the environmental fungi and 7 days for the dermatophytes. The MICs were regarded as the lowest coneentrations that did not allow any visible growth when eompared with the eontrol sets. Results: The results for the fifteen plant extraets tested against nine environmental fungai species revealed that only one extraet was able to inbibit fungai growth of two of (hese fungi (Cladosporium sp. and F. verticillioides) at a eoneentration of 50 mg/mL. The results against the two filamentous fungi dermatophytes (T. mentagrophytes and M canis) revealed these fungi to be the lllf'st susceptible to the extraets tested. Most of the extraels inhibited dermatophyte growth at eoneettrations < 50 mg/mL with the lowest MIC being registered at 3.125 mg/mL. Results for the yeast M. furfur revealed that only three plant derived extraets inhibited its growth with eoncentrations between 30 and 50 mg/mL. Conclusion: The plant extraets tested against environmental fungi and dermatophytes revealed to be more efficient against filamentous fungi dermatophyte growth. Environmental fungi followed by lhe dermatophyte yeast, showed the highest resislanee to these pIant extracts.
- Manuais escolares: um ponto de situaçãoPublication . Moreira, Darlinda; Ponte, João Pedro; Pires, Manuel Vara; Teixeira, PaulaDe uns anos a esta parte os manuais escolares constituíram-se em assunto da ordem do dia na sociedade portuguesa. Os manuais escolares interferem com muitos actores educativos e sociais, designadamente professores, alunos, pais, Ministério da Educação, editores, autores e livreiros. Estes actores, na sua qualidade de utilizadores, produtores, distribuidores ou agentes reguladores, motivados por questões de natureza pedagógica e eficiência educativa, por razões relativas à qualidade, preço e peso ou, ainda, por questões de orçamento familiar, debatem e problematizam os manuais escolares, colocando questões e suscitando reflexões que podem contribuir para uma melhoria dos processos de concepção e de utilização deste material didáctico. Para além dos problemas educativos genéricos e dos problemas sociais e políticos, os manuais escolares colocam ainda problemas específicos aos educadores matemáticos. Estes têm interesse em conhecer e compreender melhor os processos de elaboração dos manuais escolares desta disciplina, a forma como integram os projectos editoriais, os modos de utilização seguidos pelos professores, o tipo e a natureza das relações que os alunos estabelecem com os diversos manuais escolares, não esquecendo aspectos relacionados com a análise científica, pedagógica, discursiva e sociológica dos mesmos e da sua evolução ao longo dos tempos. Tendo sempre presente as questões de natureza educativa que são centrais para a discussão do papel do manual escolar, este documento pretende (i) analisar a situação relativamente aos principais assuntos em discussão na política educativa relativamente ao manual escolar, (ii) indicar os contributos da investigação portuguesa sobre os manuais escolares de Matemática, e (iii) esboçar uma agenda de investigação para os manuais escolares desta disciplina no nosso país.
- Phenolic Profile and Antioxidant and Biological Activities of Plant Extracts Rich in Hydrolyzable TanninsPublication . Melo, Adma N.F.; Afonso, Tiago B.; Pedrosa, Mariana C.; Carvalho, Marta; Rodrigues, Cláudia; Dias, Maria Inês; Ribeiro, Tânia; Machado, Manuela; Tavaria, Freni K.; Carocho, Márcio; Simas, João P.; Teixeira, Paula; Barros, Lillian; Pintado, ManuelaIn this work, hydroethanolic plant extracts (acorn husk, laurel, eucalyptus, and rockrose leaves) were screened for their content in condensed tannins (HPLC-DAD/MS), polyphenol content, antioxidant, antimicrobial, and antiviral activities, and lack of toxicity. The results showed the highest values of condensed tannins found for laurel and eucalyptus extracts, while the total phenolic content ranged within 204.54 ± 2.0/326 ± 7.0 (mg GAE/g extract), with the acorn husk extract presenting the highest content (p < 0.05). The extracts showed good antioxidant activity, which varied with the type of assay. ABTS (1013 ± 5.0/1859 ± 6.0) with the rockrose Porto extract presented the highest content, DPPH (854 ± 6.0/1565 ± 4.0) with the acorn husk extract presented the highest content, and ORAC (2855 ± 10/3703 ± 87) with the laurel extract presented the highest content; all results were expressed in μmol Trolox/g extract. The most antimicrobial extracts were the rockrose and acorn husk. In terms of virus inhibition, all extracts showed an inhibition over 90%, although eucalyptus and the acorn husk reached an inhibition close to 99%. No mutagenicity by AMES assays and no cytotoxicity were detected for the extracts. This work highlights the potential of these plant extracts representing the source of bioactive components with antioxidant capacity to be applied in foods, food packaging, development of new natural cleaning agents, and/or other applications.
- Plant extract with bioactive potential against SARS-CoV-2Publication . Melo, Adma N.F.; Afonso, Tiago B.; Carvalho, Marta; Rodrigues, Cláudia; Ribeiro, Tânia; Carocho, Márcio; Pinto, Miguel M.; Tavaria, Freni K.; Teixeira, Paula; Simas, João P.; Barros, Lillian; Pintado, ManuelaThe novel disease caused by SARS·CoV-2 has been causing chaos worldwide due to its high mortality, morbidity and contagiousness nature, and therefore forced the scientific world to develop n'ew alternatives to combat and assist the fight against this virus. Plant extracts have bioactive molecules that might provide a starting point for the research on the use of plants as an excellent source ofoew antiviral agents able to inhibit or neutralize COVID-19. Therefore, the objective ofthis study was to obtain an extract !Tom a Plaot cultivated under controlled conditions in Portugal to be used as ao antiviral substance to be applied against COVID-19. MaterialslMethods: The plant extract obtained !Tom plant cultivated under controlled conditions in Portugal was extracted by maceration in a hydroethanolic solution under optimized conditions and submitted to freeze drying. The extracts were evaluated for their phenolic profile by high performance liquid chromatography coupled to a diode array detector and a mass spectrometer detector (HPLCDAD- MS). Antioxidant activity was also measured, and antiviral properties were measured for SARSCoV- 2 in Vero cells. Remlts. HPLC analysis revealed the presence of different phenolic compounds in the extracts with relevance for caftaric acid, cis-chicoric acid and trans-chychoric acid. The extract showed a good antioxidant capacity demonstrated by the high value found for aRAC of3202,82 ± 32,52 Troloxlmg extrac!. Regarding the antiviral activity, the results achieved for the viral titer was 20 PFU/mL, and the antiviral activity for SARS-CoV-2 was 4.02 ± 0.00 Mv and the perceotage ofreduction was > 99.99%. Conclusion: The results showed that the obtained extract demonstrated consistent results of antiviral activity presenting a potential for applications against the SARS-CoV-2. Further studies are required for validation and application of this extract.
- A Quantitative Risk Assessment Model for Listeria monocytogenes in Ready-to-Eat Smoked and Gravad FishPublication . Gonzales-Barron, Ursula; Pouillot, Régis; Skjerdal, Taran; Carrasco, Elena; Teixeira, Paula; Stasiewicz, Matthew J.; Hasegawa, Akio; Mota, Juliana de Oliveira; Guillier, Laurent; Cadavez, Vasco; Sanaa, MoezThis study introduces a quantitative risk assessment (QRA) model aimed at evaluating the risk of invasive listeriosis linked to the consumption of ready-to-eat (RTE) smoked and gravad fish. The QRA model, based on published data, simulates the production process from fish harvest through to consumer intake, specifically focusing on smoked brine-injected, smoked dry-salted, and gravad fish. In a reference scenario, model predictions reveal substantial probabilities of lot and pack contamination at the end of processing (38.7% and 8.14% for smoked brined fish, 34.4% and 6.49% for smoked dry-salted fish, and 52.2% and 11.1% for gravad fish), although the concentrations of L. monocytogenes are very low, with virtually no packs exceeding 10 CFU/g at the point of sale. The risk of listeriosis for an elderly consumer per serving is also quantified. The lot-level mean risk of listeriosis per serving in the elderly population was 9.751 × 10−8 for smoked brined fish, 9.634 × 10−8 for smoked dry-salted fish, and 2.086 × 10−7 for gravad fish. Risk reduction strategies were then analyzed, indicating that the application of protective cultures and maintaining lower cold storage temperatures significantly mitigate listeriosis risk compared to reducing incoming fish lot contamination. The model also addresses the effectiveness of control measures during processing, such as minimizing cross-contamination. The comprehensive QRA model has been made available as a fully documented qraLm R package. This facilitates its adaptation for risk assessment of other RTE seafood, making it a valuable tool for public health officials to evaluate and manage food safety risks more effectively.