ESS - CQB - Posters apresentados em eventos científicos
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- Actinobacteria as new probiotics for preventing fish diseases in aquaculturePublication . Santos, Matilde; Girão, Mariana; Oliveira, Rui S.; Carvalho, FátimaIn order to meet the food needs of a constantly growing world population, aquaculture emerges as the fastest growing food production sector. However, disease outbreaks due to opportunistic bacterial pathogens cause large losses. Antibacterial chemicals used indiscriminately have resulted in resistant bacteria and antibiotic resistance genes. Ecological solutions such as probiotics are needed. Probiotics are microorganisms introduced into another organism that can have beneficial effects on the host as well as improve the external environment. Actinobacteria are an important biotechnological resource, as they produce a great diversity of secondary metabolites with a high range of bioactivities, including antimicrobial. The aim of this study was to explore the probiotic potential of some marine actinobacteria to prevent aquaculture fish diseases. For this, a screening of antimicrobial activity was performed using agar-based disk diffusion and Minimum Inhibitory Concentration (MIC) assays, against three Gram-negative bacterial fish pathogens: Aeromonas hydrophila, Edwardsiella tarda and Pseudomonas anguilliseptica. A total of 54 out of 103 actinobacterial extracts tested, presented bioactivity against these microorganisms, so that the growth of all three Gram-negative pathogens used was inhibited. The diameter of the inhibition halos varied between 8 and 20 mm. Tested extracts presented MIC values of 1000 µg/ml, except for Isoptericola chiayiensis (500 µg/ml). Microbispora bryophytorum, Isoptericola chiayiensis and Nocardia nova were some of the bacteria with the most promising results. Overall, actinobacteria associated with seaweed proved to be a potential source of probiotics to inhibit pathogens in aquaculture fish.
- Alterações anatómicas induzidas pela idade na coluna vertebral: intervenção para melhoria da saúde da comunidadePublication . Ribas, Jorge; Ribas, C.; Prudêncio, CristinaO aumento do envelhecimento da população implica uma crescente importância na implementação da política de cuidados de saúde primários. O envelhecimento leva a profundas alterações na morfologia da coluna vertebral do indivíduo. Estas alterações não estão ainda devidamente caracterizadas pelo que é necessário estudar e tipificar quais as mudanças induzidas pela idade. Desta forma será possível avaliar de que forma o patológico se poderá enquadrar num padrão normal de envelhecimento.
- Alterações morfopatológicas no rim de rato com obesidade e insulino-resistênciaPublication . Teixeira, C.; Guedes, C.; Sousa, A.; Lopes, S.; Luís, C.; Soares, R.; Baylina, Pilar; Moreira, F.; Alencastre, I.; Fernandes, RúbenA diabetes é uma das patologias com elevada taxa de comorbilidades associadas, como a nefropatia diabética que por sua vez leva a doença renal de estadio terminal (DRET). Estudos prévios demonstraram que indivíduos que desenvolveram DRET apresentavam um IMC mais elevado revelando a importância da obesidade no desenvolvimento da doença. Existe uma relação entre a atividade endócrina do tecido adiposo e a doença renal, nomeadamente o desenvolvimento de inflamação, fibrose, stress oxidativo, metabolismo lipídico anormal, uma elevada produção de insulina e maior resistência à mesma. As alterações histológicas renais mais frequentes ocorrem no glomérulo e podem ser classificadas conforme o espessamento da membrana basal glomerular, expansão mesangial ou glomerulosclerose. Avaliar as alterações histológicas renais, nomeadamente, a inflamação, fibrose e acumulação de tecido adiposo ou carboidratos. Ratos C57Bl/6J foram submetidos a dieta normal e a dieta gorda, e depois de sacrificados os tecidos (rim) foram fixados, desidratados e impregnados em parafina. Cortes histológicos foram submetidos às seguintes colorações: Hematoxilina e Eosina, Ácido Periódico de Schiff (PAS), PAS e Azul de Alcian e Tricrómio de Masson. Em ratos obesos insulino-resistentes, observou-se uma alteração de tamanho dos glomérulos e um evidente aumento do espaço capsular. Há também uma alteração da arquitetura e organização estrutural a nível tubular e uma evidente acumulação de gotículas de lípidos. Contrariamente ao esperado não foram encontradas evidências de fibrose. Conclusão: Todas as alterações esperadas foram encontradas nos cortes histológicos de tecido exceto a ausência de fibrose. Mais estudos serão necessários no sentido de perceber a relação entre este fator e a doença renal.
- Anti-pneumoscystis carinni activitiy of primaquine imidazolidin-4-onesPublication . Vale, Nuno; Ferraz, Ricardo; Azevedo, Joana; Araújo, Maria João; Moreira, Rui; Collins, Margaret S.; Cushion, Melanie T.; Gomes, PaulaPneumocystis pneumonia (PCP) is one of the most frequent causes of mortality among HIV-infected patients. Primaquine (PQ) is an antimalarial 8-aminoquinoline effective against PCP when given in combination with clindamycin. This has drawn the attention of Medicinal Chemists towards the anti-PCP activity of 8-aminoquinolines, not only confined to those exhibiting antimalarial activity [1]. It is thought that anti-PCP 8-aminoquinolines exert their anti-PCP activity by acting on the electronic transport and redox system of the P. carinii pathogen [1]. Recently, our research group has been developing imidazolidin-4-one derivatives of PQ (Scheme 1), targeting novel compounds with improved therapeutic action, namely, higher resistance to metabolic inactivation, lower toxicity and equal or higher antimalarial activity than that of the parent drug [2,3]. These imidazolidin-4-ones were seen to block the transmission of rodent malaria, caused by Plasmodium berghei on BalbC mice, to the mosquito vector Anopheles stephensi [3]. The anti-PCP activity of our PQ derivatives is now under study and preliminary in vitro assays [4] show that some of the compounds exhibit slight to moderate activity after a 72 h incubation period against P. carinii. In one case, the IC50 was comparable to that of parent PQ. Both these studies and forthcoming results from ongoing biological assays will be presented and discussed.
- Antibacterial activity of ionic liquids based on betalactamantibiotics against resistant bacteriaPublication . Dias, Vitorino; Santos, Miguel; Prudêncio, Cristina; Noronha, João P.; Grilo, Inês R.; Sobral, Rita G.; Dias, Ana Rita; Branco, Luís C.; Ferraz, RicardoThe cases of antibiotic resistance are increasing and becoming more and more common, giving rise to a new problem for public health. Therefore, the discovery of new antibiotics is important and necessary.
- Antifungal activity of Imidazolidin-4-ones of the antimalarial primaquinePublication . Ferraz, Ricardo; Fernandes, Rúben; Vieira, Mónica; Barros, Piedade; Gomes, Paula; Prudêncio, CristinaThe 5-Isopropyl-3-[4-(6-methoxy-quinolin-8-ylamino)-pentyl]-2,2-dimethyl-imidazolidin-4-one (ValPQacet) was sinthesized through acylation of the anti-malarial primaquine with α-valine and subsequent reaction of the resulting -aminoamide with propanone (Sheme 1).Imidazolidin-4-ones of the anti malarial primaquine are being sinthesized to develop new variants in order to improve more effective treatments against malaria . Recently it has been observed that primaquine derivates could have effect in a new kind of yeast . To study the fungicidal activity against Candida albicans, Candida tropicalis, Issatchenkia orientalis, Sacharomyces cerevisae, the ValPQacet was put in the form of the hydrochloride salt. The minimal inhibitory concentration (MIC) could be determined for all yeast in the concentration range assayed. Also was determined MIC’s of primaquine hydrochloride salt for all yeast, and this shows that the parent drug is less active than our compound. Further studies are being performed to determine viability and cellular injury with this drugs.
- Antimicrobial activity of pyrazine and quinoxaline N,N’-dioxide heterocyclic compoundsPublication . Vieira, Mónica; Ferraz, Ricardo; Fernandes, Rúben; Noronha, João Paulo; Silva, M.; Prudêncio, CristinaThe nitrogen heterocyclic organic compounds 1,4 dioxide pyrazine and quinoxaline derivatives have been widely studied due to their potential use as synthetic drugs. The thermochemical study of three N,N´-dioxides: 2,3,5-trimethylpyrazine-1,4-dioxide, tetramethylpyrazine-1,4-dioxide and 6-chloro-2,3-dimethilquinoxaline 1,4-dioxide has been recently developed in order to establish relationships among the energetical, structural and reactivity properties [4,5]. Several studies have reported their pharmacological activity, particularly as antimicrobial agents [1,2,3]. It has also been established a relation between energetical and structural properties and biological activity, once these compounds present N – oxide bonds, increasing their oxidative capacity. The present work reports the study of antimicrobial activity for those compounds against the bacteria Geobacillus stearothermophylus, Staphylococcus aureus, Streptococcus agalactiae, Escherichia coli and also against the yeasts Saccharomyces cerevisiae PYCC 4072, Candida albicans PYCC3436T, Candida tropicalis PYCC, Issatchenka Orientalis PYCC. The determination of the minimal inhibitory concentration (MIC), points to an antimicrobial activity and the preliminary results indicate that these compounds may be potential candidates as antimicrobial drugs with clinical, agriculture or food industries applications.
- Antimicrobial properties of PLA scaffolds functionalized via LbL method with Manuka and multifloral honeyPublication . Alves, Inês; Ferraz, Ricardo; Prudêncio, Cristina; Rufo, João; Prudêncio, Cristina; Cavaleiro Rufo, JoãoTissue engineering and chronic wound management face obstacles due to the global rise of resistances. Natural bioactive agents, such as Manuka honey, offer a unique therapeutic profile by combining antimicrobial activity with the ability to modulate the biochemical wound environment and promote cellular regeneration. However, the seamless integration of these biological compounds into synthetic matrices, such as polylactic acid (PLA), remains a challenge. This study aims to develop PLA scaffolds functionalised with honey using the Layer-by-Layer (LbL) technique and evaluate their inhibitory capacity against microbial growth. Two honey types are com-pared, MGO 263+/UMF10+ Manuka honey and a Portuguese multifloral honey. Concentrations of 15%, 20%, 25%, 30% and 35% will be tested by diluting the honey in 3M sodium acetate buffer and adjusting pH to 5.5. The method has currently been successfully optimized for the 15% concentration. The LbL process consist-ed of three immersion cycles, alternating with coating in the honey solutions, washing in acetate buffer and short periods of drying. As a negative control, PLA scaffolds were subjected only to the washing steps. Biological activity was assessed against Escherichia coliand Staphylococcus aureus. In the disc diffusion test, the plates were inoculated uniformly and the scaffolds arranged in quadrants, including positive controls of ciprofloxacin for E. coli andpenicillin G for S. aureus. After incubation, inhibition was quantified by two per-pendicular measurements of the halo. Quantification of Colony-Forming Units (CFU) was performed after recovery of the microorganisms from the scaffolds by vortexing and centrifugation in saline solution. The study is currently in the optimization phase. Sterilization has been successfully achieved by im-mersing the scaffolds in 70% ethanol for 2 hours with gentle stirring, followed by vacuum drying in a Petry dish for 24 hours. Microscopic observation of the scaf-folds showed a clear coating layer in functionalized samples. This research seeks to validate LbL functionalisation as a simple strategy for developing bioactive scaffolds. The present work establishes a foundation for subsequent phases involving various honey concentrations, with the goal of demonstrating a synergistic effect between the PLA scaffold and nat-ural antimicrobial agents.
- Antimicrobial resistance in bacterial strains isolated from different types of Portuguese cheesePublication . Amador, P.; Fernandes, Ruben; Tato-Costa, J.; Teles-Grilo, L.; Brito, L.; Prudêncio, CristinaThe present work aimed to study an eventual antimicrobial resistance and the presence of β-lactamases in enterobacteria isolated from cheese. β-lactams are among the most common antibiotics used for bacterial infections. Rates of bacterial resistance to antimicrobial agents are increasing world wide and the presence of β-lactamases is among one of the most common resistance mechanisms. In the present study we used twenty cheese samples, corresponding to six different types of Portuguese cheese, collected from local retail establishments. Samples were screened for the presence of β-lactams resistant Enterobacteriaceae in selective media with high concentration values of ampicilin. Colonies presumed to be resistant to ampicilin were further confirmed by antibiogram testing against other 13 different antibiotics, including six β-lactams. A total of 160 isolates were recovere from the selective media. The presence of β-lactamases on colonies was detected by adding nitrocefin to the cell biomass. After antibiogram testing about 40 isolates were confirmed to be resistant to, at least, one β -lactam subclass. The results obtained in this study point out to the presence, in different cheese samples, of Enterobacteriaceae resistant to β-lactams and the presence of β-lactamases. These results suggest that cheese may be a source of potential resistance transfer to the normal gastrointestinal flora of the consumer,which may be a cause of serious public health problems.
- Aquisição de competências no domínio da Bioética: perspectiva dos estudantes de enfermagemPublication . Bouças, I.; Nunes, C.; Fonte, R.; Prudêncio, C.Averiguar junto dos estudantes de Enfermagem sobre a importância atribuída ao ensino da Bioética na aquisição de competências profissionais, analisando três dimensões: percepção em relação às temáticas da Bioética, Enfermagem e Bioética em Enfermagem; importância/responsabilidade atribuída à Bioética em Enfermagem; práticas educativas em foco no contexto do currículo formal da Licenciatura em Enfermagem.