Differences between Pseudomonas aeruginosa non-adapted and adapted to benzalkonium chloride : comparison of adhesion capacity, and susceptibility of biofilms to removal and surfactant attack

Bacteria adhesion, and consequent biofilm formation, in vitro and in vivo, are phenomena that often occur naturally but are also bacteria´s strategies to protect themselves from stress factors, playing probably an important role in virulence. Furthermore, bacteria growing in biofilms are less susceptible to many antibacterial agents than their suspended counterparts. These factors emphasize the need of suitable and efficient surface disinfection procedures in order to reduce the overgrowth of resistant microorganisms in response to an ineffective course of antimicrobials. In this study, we examined the effect of adaptation of P. aeruginosa to a surfactant, benzalkonium chloride (BZK), on the adherence of bacterial cells to PET, conditioned and non-conditioned with BZK, and on their ability to resist to removal and BZK aggression. The assays were carried out in a PPFC. Bacterial adaptation was attained by exposing P. aeruginosa to gradual increasing concentrations of BZK, and selected in TSA supplemented with 4.0 mM BZK. The results show that adapted P. aeruginosa adhered in a more extent than the non-adapted counterpart. For both strains, the pre-conditioning of the PET surfaces significantly favored bacterial adhesion. The higher adhesion was observed with the adapted bacteria onto the conditioned PET coupons. These results highlight that the extent of adhesion is greater the higher are the stress factors. The strength of adhesion is also higher in the case of adapted bacteria since detachment only occurs with P. aeruginosa non-adapted. BZK application did not cause significant removal except for P.aeruginosa non-adapted adhered to non-conditioned PET. Nevertheless, BZK attack causes loss of viability of the cells that remained adhered to the surfaces, this loss being more notorious in the case of non adapted cells adhered in the conditioned surfaces. Based on the results it can be said that the presence of BZK residues on the adhesion surfaces did not impair the bacterial adhesion capacity though affects the viability of the adhered cells. It can also be concluded that resistant bacteria that survived to a simple adaptation step to a common antimicrobial agent increased its adherence ability and insusceptibility to removal and antimicrobial treatment. In a disinfection point of view, these results can represent additional problems for the eradication of pathogenic bacteria with increased virulence from equipment and surfaces in the medical arenas

Behavior of single and mixed biofilms subjected to benzalkonium chloride : the impact of using chemical-adapted bacteria

The majority of lab‐scale studies involves a single species to form biofilms and to later evaluate the effect of the antimicrobials against these biofilms. However, in real systems, biofilms can be found as a complex consortium of species where the biofilm behaviour is the sum of the synergistic and antagonistic interactions between the different species. It is not surprising that disinfection protocols developed with a single species biofilm can fail when applied to a real system. The central query of this study was to understand the behaviour of binary biofilms when exposed to high doses of benzalkonium chloride (BZK), a general disinfectant in health care facilities. P. aeruginosa (ATCC 10145), P. aeruginosa adapted to 4.0 mM of BZK (PA4) and Escherichia coli k12 were the strains used to form single and binary biofilms. The mixed‐species biofilms were obtained by a combination of 50% of suspended inocula of each specie: E. coli with P. aeruginosa and E. coli with PA4. The role of surface preconditioning with BZK on biofilm properties was also investigated. Biofilms where formed for 24 h in 96 plates (non‐ and conditioned with 0.7 mM of BZK for 30 min), being then treated with 1.0 mM of BZK. Crystal violet (CV) together with XTT, were used to assess, respectively, total attached biomass and respiratory activity. The number of CFU/cm2 was also determined. The data emphasised that the characteristics of the binary biofilms depend on the strains that formed them. In fact, when the adapted strain is involved, the resulting biofilms have less mass, activity and cells. It is also observed that, for both single‐ and dual‐species biofilms, surface preconditioning significantly favoured biofilm formation. Although the BZK preconditioning of the surfaces increased biomass, it simultaneous appeared to weak bacterial adhesion, since BZK attack reduced significantly the amount of biofilm comparing to the clear surfaces, for both single‐ and mixed‐species. Concerning the data related with BZK attack, for both non‐ and conditioned surfaces, there was a notorious reduction of the bacterial activity and number of cells, in both single and mixed biofilms. But, the PA4 and E. coli binary biofilms seemed to reveal recalcitrant behaviour since the CFU still unaltered after BZK attack. These data suggest that when biofims are formed by the PA4 and E. coli, it seems to exist an competitive behaviour between the bacteria that give rise to a mixed biofilm with fewer mass and cells. However, these biofilms are less susceptible to the action of BZK, sign of a possible protective effect of one species to another. Since few reports specifically address interactions within multi‐species biofilms, these results highlight the importance of understanding the multiple behaviours of biofilms as a community and a complex web of interactions.Universidade do Minho. Centro de Engenharia Biológica. Instituto de Biotecnologia e Bioengenharia (IBB-CEB) e Fundação para a Ciência e a Tecnologia (FCT) - PTDC/SAU‐ESA/64609/2006, SFRH/BD/31065/200

Role of planktonic and sessile extracellular signals on interspecies relationships

Universidade do Minho. Centro de Engenharia Biológica. Instituto de Biotecnologia e Bioengenharia (IBB-CEB) e Fundação para a Ciência e a Tecnologia (FCT) - PTDC/SAU-ESA/64609/2006; SFRH/BD/31065/200

Antioxidant and anti-inflammatory activities of cytocompatible Salvia officinalis extracts: A comparison between traditional and soxhlet extraction

Chronic inflammation is characterized by an overproduction of several inflammatory mediators (e.g., reactive species and interleukins -IL) that play a central role in numerous diseases. The available therapies are often associated with serious side effects and, consequently, the need for safer drugs is of utmost importance. A plant traditionally used in the treatment of inflammatory conditions is Salvia officinalis. Therefore, conventional maceration and infusion of its leaves were performed to obtain hydroethanolic (HE-T) and aqueous extracts (AE-T), respectively. Their efficacy was compared to soxhlet extracts, namely aqueous (AE-S), hydroethanolic (HE-S), and ethanolic extracts (EE-S). Thin-layer chromatography demonstrated the presence of rosmarinic acid, carnosol, and/or carnosic acid in the different extracts. Generally, soxhlet provided extracts with higher antioxidant activities than traditional extraction. Moreover, under an inflammatory scenario, EE-S were the most effective, followed by HE-S, HE-T, AE-T, and AE-S, in the reduction of IL-6 and TNF-α production. Interestingly, the extracts presented higher or similar anti-inflammatory activity than diclofenac, salicylic acid, and celecoxib. In conclusion, the extraction method and the solvents of extraction influenced the antioxidant activity, but mainly the anti-inflammatory activity of the extracts. Therefore, this natural resource can enable the development of effective treatments for oxidative stress and inflammatory diseases.Fundação para a Ciência e a Tecnologia (FCT) to the PhD grant of SV (PD/BD/135246/2017) and the projects PATH (PD/00169/2013), Cells4_IDs (PTDC/BTM-SAL/28882/2017) and the NORTE 2020 Structured Project, cofunded by Norte2020 (NORTE-01-0145-FEDER-000021

Infecções do trato urinário

O sistema urinário é uma das quatro vias de excreção existentes no corpo humano. A sua exposição a factores exteriores e/ou interiores torna-o sensível a diversas infecções, pelo que, actualmente, em termos de quadro clínico. as patologias relacionadas com as infecções do tracto urinário (ITU), nomeadamente, a uretrite, cistite, síndroma uretral agudo e pielonefrite, são bastantes comuns

Avaliação de alternativas aos revestimentos com alcatrão de hulha para estruturas de aço total ou parcialmente imersas em estuário e água do mar

Na procura de revestimentos anticorrosivos para protecção de estruturas de aço total ou parcialmente imersas em estuário e água do mar, que sejam alternativas mais ecológicas aos revestimentos com alcatrão de hulha ainda utilizados, foi desenvolvido um projecto no qual se comparam revestimentos epoxídicos comerciais com um revestimento de alcatrão de hulha epoxídico de referência, também comercial. Este trabalho inclui, para além da avaliação da protecção anticorrosiva dos revestimentos envolvidos no projecto, quer em laboratório, quer em exposição natural em estuário (rios Sado e Tejo) e em mar (Sines) durante quatro anos, a caracterização laboratorial das tintas integradas nos diferentes esquemas de pintura que deram origem aos revestimentos em estudo. Os resultados da avaliação no fim de dois anos de exposição natural, complementados com os ensaios em laborató permitiram concluir que dois dos quatro revestimentos alternativos estudados apresentaram melhor comportamento anticorrosivo do que o revestimento com alcatrão de hulha epoxídico usado como referência

Valorization of Phenolic and Carotenoid Compounds of Sechium edule (Jacq. Swartz) Leaves: Comparison between Conventional, Ultrasound- and Microwave-Assisted Extraction Approaches

Chayote leaves are known for culinary and traditional medicine applications. This work intended to recover carotenoids and phenolic compounds from chayote leaves using the ultrasound-assisted extraction (UAE). A Box–Behnken design was employed to investigate the impact of extraction time, temperature, and ultrasonic power on the recovery of total carotenoids, total phenolic compounds, and antioxidant activities. For comparative purposes, chayote leaf extracts were prepared by maceration (ME) and microwave-assisted extraction (MAE), using the same time and temperature conditions optimized by UAE. Extraction at 50 °C and 170 Watts for 30 min provided the optimal UAE conditions. UAE showed better extraction efficacy than ME and MAE. The HPLC analysis of the extracts showed that the xanthophyll class was the main class of carotenoids, which constituted 42–85% of the total carotenoid content, followed by β-carotene and tocopherol. Moreover, 26 compounds, classified as phenolic acids, flavonols, flavonoids and other polar compounds, were identified in the chayote leaf extracts. Flavonols accounted for 55% of the total compounds quantified (the major compound was myricetin) and phenolic acids represented around 35%, mostly represented by ferulic acid, chlorogenic acid and (+)-catechin. This study revealed the potential of UAE as an effective green extraction technique to recover bioactive compounds from chayote leaves, for food, and for pharmaceutical and cosmetic applicationsThis work was supported through the projects UIDB/50006/2020 and UIDP/50006/2020, funded by FCT/MCTES through national funds. Elsa F. Vieira and Manuela Moreira thank FCT (Fundação para a Ciência e Tecnologia) for funding through the Scientific Employment Stimulus-Individual Call (Ref. CEECIND/03988/2018 and CEEC- IND/02702/2017, respectively). The authors also thank the project SYSTEMIC “an integrated approach to the challenge of sustainable food systems: adaptive and mitigatory strategies to address climate change and malnutrition”. The Knowledge hub on Nutrition and Food Security has received funding from national research funding parties in Belgium (FWO), France (INRA), Germany (BLE), Italy (MIPAAF), Latvia (IZM), Norway (RCN), Portugal (FCT), and Spain (AEI) in a joint action of JPI HDHL, JPI-OCEANS and FACCE-JPI, launched in 2019, under the ERA-NET ERA-HDHL (no 696295)info:eu-repo/semantics/publishedVersio

On the bioactivity of Echinacea purpurea extracts to modulate the production of inflammatory mediators

Inflammatory diseases are the focus of several clinical studies, due to limitations and serious side effects of available therapies. Plant-based drugs (e.g., salicylic acid, morphine) have become landmarks in the pharmaceutical field. Therefore, we investigated the immunomodulatory effects of flowers, leaves, and roots from Echinacea purpurea. Ethanolic (EE) and dichloromethanolic extracts (DE) were obtained using the Accelerated Solvent Extractor and aqueous extracts (AE) were prepared under stirring. Their chemical fingerprint was evaluated by liquid chromatography–high resolution mass spectrometry (LC-HRMS). The pro- and anti-inflammatory effects, as well as the reduction in intracellular reactive oxygen and nitrogen species (ROS/RNS), of the different extracts were evaluated using non-stimulated and lipopolysaccharide-stimulated macrophages. Interestingly, AE were able to stimulate macrophages to produce pro-inflammatory cytokines (tumor necrosis factor -TNF-α, interleukin -IL-1β, and IL-6), and to generate ROS/RNS. Conversely, under an inflammatory scenario, all extracts reduced the amount of pro-inflammatory mediators. DE, alkylamides-enriched extracts, showed the strongest anti-inflammatory activity. Moreover, E. purpurea extracts demonstrated generally a more robust anti-inflammatory activity than clinically used anti-inflammatory drugs (dexamethasone, diclofenac, salicylic acid, and celecoxib). Therefore, E. purpurea extracts may be used to develop new effective therapeutic formulations for disorders in which the immune system is either overactive or impaired.This research was funded by the Fundação para a Ciência e a Tecnologia (FCT) to the PhD grant of SFV (PD/BD/135246/2017 and COVID/BD/152012/2021) and the projects PATH (PD/00169/2013), FROnTHERA (NORTE-01-0145-FEDER-000023), Cells4_IDs (PTDC/BTM-SAL/28882/2017), and the NORTE 2020 Structured Project, co-funded by Norte2020 (NORTE-01-0145-FEDER-000021). This research was also partially supported by national funds by FCT through the projects UIDB/04423/2020 and UIDP/04423/2020 (Group of Natural Products and Medicinal Chemistry-CIIMAR) and ERDF, through the COMPETE—POFC program in the framework of the program PT2020

O papel da investigação na prática pedagógica dos mestrados em ensino

Os mestrados em ensino da Universidade do Minho preveem a formação do professor/ educador como prático reflexivo e intelectual crítico, conferindo um lugar de relevo à investigação pedagógica no estágio através da construção e avaliação de um “projeto de intervenção pedagógica supervisionada” que deve enquadrar-se numa visão democrática da educação. O projeto dá origem a um relatório final, defendido em provas públicas. Com o objetivo de compreender o papel da investigação no estágio, foi analisado um corpus de 28 relatórios de 5 mestrados de diversos níveis de ensino, com base numa grelha incidente na visão de educação subjacente aos projetos, no tipo e função do conhecimento mobilizado, na articulação investigação-ensino e no valor educativo das intervenções. Os projetos evidenciam a importância da investigação no desenvolvimento de práticas educativas focadas na qualidade dos processos de ensino e de aprendizagem, embora a coexistência de diferentes modalidades de articulação investigação-ensino sinalize conceções diferenciadas de formação e da função da investigação na regulação das práticas e na (re)construção de competências profissionais. A partir das potencialidades e limitações observadas, traçam-se linhas de ação futura para a construção de uma cultura investigativa na formação inicial de professores/ educadores

A new chalcone derivative with promising antiproliferative and anti-invasion activities in glioblastoma cells

Glioblastoma (GBM) is the most common and most deadly primary malignant brain tumor. Current therapies are not effective, the average survival of GBM patients after diagnosis being limited to few months. Therefore, the discovery of new treatments for this highly aggressive brain cancer is urgently needed. Chalcones are synthetic and naturally occurring compounds that have been widely investigated as anticancer agents. In this work, three chalcone derivatives were tested regarding their inhibitory activity and selectivity towards GBM cell lines (human and mouse) and a non-cancerous mouse brain cell line. The chalcone 1 showed the most potent and selective cytotoxic effects in the GBM cell lines, being further investigated regarding its ability to reduce critical hallmark features of GBM and to induce apoptosis and cell cycle arrest. This derivative showed to successfully reduce the invasion and proliferation capacity of tumor cells, both key targets for cancer treatment. Moreover, to overcome potential systemic side effects and its poor water solubility, this compound was encapsulated into liposomes. Therapeutic concentrations were incorporated retaining the potent in vitro growth inhibitory effect of the selected compound. In conclusion, our results demonstrated that this new formulation can be a promising starting point for the discovery of new and more effective drug treatments for GBM.This research was funded by FCT to the PhD grant of DM fellowship (PD/BD/143038/2018) and the projects PATH (PD/00169/2013), FROnTHERA (NORTE-01-0145-FEDER-000023), Cells4_IDs (PTDC/BTM-SAL/28882/2017) and the NORTE 2020 Structured Project, co-funded by Norte2020 (NORTE-01-0145-FEDER-000021). This research was also supported by the Strategic Funding UIDB/04423/2020 and UIDP/04423/2020 (Group of Natural Products and Medicinal ChemistryCIIMAR) through national funds provided by the FCT and ERDF, within the framework of the program PT2020. Joana Moreira acknowledges her grant (SFRH/BD/135852/2018)