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Genomic Characterization of Multidrug-Resistant and ESBL-Producing Klebsiella pneumoniae Isolated from Healthy Rabbits Intended for Human Consumption
Publication . Silva, Vanessa; Caniça, Manuela; Rivière, Rani; Silva, Adriana; Poeta, Patrícia; Igrejas, Gilberto; LAQV@REQUIMTE; Faculdade de Ciências e Tecnologia (FCT); DQ - Departamento de Química; MDPI AG
Klebsiella pneumoniae is an important pathogen associated with multidrug resistance and virulence in both human and animal populations. While its prevalence and resistance patterns are well documented in clinical settings, data on K. pneumoniae in food-producing animals remain scarce. This study aimed to isolate and characterize multidrug-resistant K. pneumoniae strains from healthy rabbits raised for human consumption, with a focus on antimicrobial resistance genes, plasmid content, and associated mobile genetic elements. A total of 295 fecal samples were collected from rabbits across 20 commercial farms in northern Portugal. Isolates were confirmed using MALDI-TOF MS, tested for hypermucoviscosity, and subjected to antimicrobial susceptibility testing (EUCAST). Whole-genome sequencing (WGS) was performed to determine sequence types (STs), resistance genes, plasmids, and resistance determinants for metals and biocides. Six K. pneumoniae isolates were recovered, showing extensive antimicrobial resistance profiles, including ESBL genes such as blaCTX-M-15, blaSHV-28, and blaTEM-1. The most frequent ST was ST307. Multiple genes resistant to heavy metals were identified. Plasmid analysis revealed the presence of IncFII, IncN, and ColRNAI types. Network analysis showed clusters of genetically related isolates and highlighted shared resistance mechanisms. The presence of multidrug-resistant K. pneumoniae in healthy rabbits destined for human consumption underscores the zoonotic potential of this species and the need for surveillance in the animal–food–human interface. These findings contribute to a better understanding of resistance ecology in the context of One Health.
Dual-site engineering of N vacancies and K single-atoms in C3N4
Publication . Xu, Xiao; Xiao, Yao; Xu, Xuelian; Carabineiro, Sónia A. C.; Zhu, Junjiang; LAQV@REQUIMTE; DQ - Departamento de Química; Chinese Ceramic Society
Graphitic carbon nitride (C3N4) is a promising photocatalyst due to its suitable band gap and polymer properties, but its efficiency is limited by the poor separation of photoinduced electron/hole (e–/h+) pairs. To address this issue, we propose creating N vacancies within the layers and bridging K single-atoms between the C3N4 layers through the self-assembly of potassium citrate and melamine–urea monomers. The introduction of N vacancies disrupts the symmetry of C3N4, promoting electron transfer along the delocalized π-conjugated network, while the presence of K atoms provides channels for electron transfer between the layers by forming N[sbnd]K[sbnd]N bridges, thereby leading to significant enhancement in the separation and transfer of e–/h+ pairs across spatial dimension. As expected, the co-modified C3N4, with N vacancies and K single-atoms (designated as CN-K-VN), exhibits excellent photocatalytic performance, with reaction rate constant of 9.69 × 10−2 min−1 (7.39 × 10−2 min−1 in real water environment) for tetracycline, achieving 80% degradation of tetracycline within 20 min. The reaction mechanism, as well as the toxicity of the degradation intermediates, is deeply discussed. This study provides a strategy to enhance the spatial separation of electrons for photocatalyst, highlighting its significance role in photocatalysis.
In Vitro, Ex Vivo, and In Vivo Evaluation of Silver Nanoparticles Synthesized Using Green Tomato Extract
Publication . Cunha, Daniela; Faria-Silva, Catarina; Carvalho, Filomena A.; Ascensão, Lia; Simões, Pedro; Carvalheiro, Manuela; Simões, Sandra; LAQV@REQUIMTE; DQ - Departamento de Química; MDPI - Multidisciplinary Digital Publishing Institute
Biogenic silver nanoparticles (AgNP) are among the fastest-growing nanomaterials due to the simplicity, efficiency, and sustainability of their biosynthesis using phytochemicals as reducing and coating agents. The agro-food industry generates large quantities of organic waste, a renewable source of biomolecules for AgNP biosynthesis. The main objective of this work was to prepare and characterize biogenic AgNP using a green tomato waste extract (TE) obtained by subcritical water extraction. To the best of our knowledge, this is the first report on the use of such an extract in the synthesis of AgNP. The effects of the TE and AgNO3 concentrations, reaction time, pH, and temperature on AgNP physico-chemical characteristics and on in vitro cytotoxicity against HaCaT and THP-1 cells were assessed. Antimicrobial activity was determined in vitro and ex vivo. The wound-healing capability of AgNP was evaluated in vivo in an incisional wound mouse model. The developed AgNP have a Surface Plasmon Resonance (SPR) band between 402 and 406 nm and a size of ±60 nm, and they are negatively charged (−42 mV) and spherical. In vitro and ex vivo studies prove that AgNP do not compromise skin cells and can decrease cutaneous irritation. The AgNP formulated in a gel revealed similar wound-healing properties to a commercial silver-containing topical ointment. Overall, the biogenic synthesis of AgNP employing an extract of agricultural waste obtained by an eco-friendly method is simple and cost-effective and presents the potential for application in skin disease management.
Global atomic and group contribution models for prediction of the thermal conductivities of deep eutectic solvents
Publication . Soltani, Fatemeh; Haghbakhsh, Reza; Raeissi, Sona; LAQV@REQUIMTE; DQ - Departamento de Química; Elsevier Science B.V., Amsterdam.
Deep Eutectic Solvents (DESs) are often categorized as novel green solvents. Knowledge of the thermal conductivity of a solvent in an industrial process is vital for the optimization of energy utilization. Considering the vast number of DESs introduced to date, it is practically impossible to measure all their thermal conductivities. Thus, it is vital to have predictive models that can predict the thermal conductivities of various DESs, and at different temperatures. For this purpose, a large data bank was collected, including 338 data points from 56 DESs of various natures. The data were used to develop a group contribution (GC) model and an atomic contribution (AC) model to predict the thermal conductivities of DESs. The calculated AARD% values of 7.62 % and 9.52 % for the proposed GC and AC models, respectively, indicated reliable performance and promising predictions for both models. The models were also compared to well-known literature models.
Design of magnetic kappa-carrageenan-collagen bioinks for 3D bioprinting
Publication . Almeida, Duarte; Küppers, Freya; Gusmão, Afonso; Manjua, Ana C.; Ferreira, Catarina F.R.; Portugal, Carla A.M.; Silva, João C.; Sanjuan-Alberte, Paola; Ferreira, Frederico Castelo; LAQV@REQUIMTE; DQ - Departamento de Química; Springer
Bioprinting approaches are of great promise for tissue engineering applications as they allow the fabrication of constructs able to mimic native tissues’ mechanical and topographical features. Additional control over cells fate can be enhanced using stimuli-responsive materials, requiring the development of novel bioinks for this purpose. In this study, bioinks comprising κ-carrageenan, collagen, and magnetic nanoparticles were designed for 3D bioprinting applications. The characterization of this material was performed, where mechanical compressive tests yielded Young’s moduli ranging from 8.25 to 18.4 kPa. Rheological assessments also revealed the shear-thinning behavior of the bioinks and a temperature-dependent gelation. The capability of these bioinks to produce 3D constructs by extrusion bioprinting was established through the printability evaluation and the development of complex structures, supporting the viability and proliferation of mesenchymal stromal cells (MSCs). Finally, as proof-of-concept, it was observed that the secretome of bioprinted MSCs stimulated with an external magnetic field of 80 mT was able to increase the number of tubes formed by human umbilical vein endothelial cells.
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Fundação para a Ciência e a Tecnologia
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Concurso para Atribuição do Estatuto e Financiamento de Laboratórios Associados (LA)
Número da atribuição
LA/P/0008/2020