Browsing by Author "Campos, Maria J."
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- Detection of plasmid mediated colistin resistance (MCR-1) in Escherichia coli and Salmonella enterica isolated from poultry and swine in SpainPublication . Quesada, Alberto; Ugarte-Ruiz, María; Iglesias, M. Rocío; Porrero, M. Concepción; Martínez, Remigio; Florez-Cuadrado, Diego; Campos, Maria J.; García, María; Píriz, Segundo; Sáez, José Luis; Domínguez, LucasRecent findings suggest that use of colistin as a last resort antibiotic is seriously threatened by the rise of a new plasmid mediated mechanism of resistance (MCR-1). This work identifies, for the first time in Southern Europe, the gene mcr-1 in nine strains from farm animals (poultry and swine) corresponding to five Escherichia coli and four Salmonella enterica, amongwhich three belong to serovar Typhimuriumand one to Rissen. TheMCR-1 was found encoded by a plasmid highly mobilizable by conjugation to the E. coli J53 strain. Two E. coli strains carried two determinants, mcr-1 plus pmrA or pmrB mutations, known to confer colistin resistance.
- Escherichia coli ST167 carrying plasmid mobilisable mcr-1 and blaCTX-M-15 resistance determinants isolated from a human respiratory infectionPublication . Sánchez-Benito, Rosario; Iglesias, M. Rocío; Quijada, Narciso M.; Campos, Maria J.; Ugarte-Ruiz, María; Hernández, Marta; Pazos, Carmen; Rodríguez-Lázaro, David; Garduño, Eugenio; Domínguez, Lucas; Quesada, Alberto
- Influence of Codium tomentosum Extract in the Properties of Alginate and Chitosan Edible FilmsPublication . Augusto, Ana; Dias, Juliana R.; Campos, Maria J.; Alves, Nuno; Pedrosa, Rui; Silva, SusanaThe growing search for natural alternatives to synthetic food packaging materials and additives has increased, and seaweed extracts’ bioactivity has made them suitable candidates for incorporation in novel edible films. This study aims to investigate the effect of Codium tomentosum seaweed extract (SE) incorporation in alginate and chitosan edible films. Alginate- and chitosan-based films with and without the incorporation of 0.5% SE were characterized according to their physical, optical, mechanical, and thermal properties. Seaweed extract incorporation in chitosan films resulted in an increase of film solubility (50%), elasticity (18%), and decrease of puncture strength (27%) and energy at break (39%). In alginate films, the extract incorporation significantly decreased film solubility (6%), water vapour permeability (46%), and elasticity (24%), and had no effect on thermal properties. Depending on the type of application, the addition of SE in edible films can bring advantages for food conservation.
- Insights into the restoration of tributyltin contaminated environments using marine bacteria from Portuguese fishing portsPublication . Monteiro, Hugo R.; Moutinho, Ariana; Campos, Maria J.; Lemos, Marco F.L.; Esteves, Ana C.Tributyltin (TBT) is an organotin chemical mainly used as biocide in marine antifouling paints. Despite the restrictions and prohibitions on its use, TBT is still an environmental problem due to its extensive application and subsequent release into the environment, being regarded as one of the most toxic chemicals released into the marine ecosystems. Microorganisms inhabiting impacted sites are crucial for their restoration since they have developed mechanisms to tolerate and break down pollutants. Nonetheless, transformation products resulting from the degradation process may still be toxic or, sometimes, even more toxic than the parent compound. The determination of the parent and degradation products by analytical methods, although necessary, may not be ecologically relevant since no information is provided regarding their ecotoxicity. In this study, marine bacteria collected from seven Portuguese fishing ports were isolated and grown in the presence of TBT. Bacteria that exhibited higher growth were used to bioremediate TBT-contaminated waters. The potential of these bacteria as bioremediation agents was evaluated through ecotoxicological assays using the sea snail Gibbula umbilicalis as model organism. Data suggested that some TBT-tolerant bacteria, such as Pseudomonas putida, can reduce the toxicity of TBT contaminated environments. This work contributes to the knowledge of TBT-degrading bacteria.
- Morphology and Thermal Behaviour of New Mycelium-Based Composites with Different Types of SubstratesPublication . Alves, Rafael M. E.; Alves, M.L.; Campos, Maria J.The need for new green and sustainable materials has been fostering the development, research and introduction of biodegradable materials from natural and renewable sources. Commercially available biodegradable plastics, while minimizing their environmental impact and exhibiting a set of properties that enable the obtainment of industrial components, usually require complex processing methods, are costly and have limited applicability. A new growth of natural resources based paradigm applied as production process is increasing its relevance as an alternative production process. New materials that combine fungal mycelium with waste materials as coffee grounds or wood waste can be considered as promising to fulfill this new paradigm. This new biomaterial mycelium based composites present controllable and adjustable properties during their growth, being able to grow and penetrate organic substrates, thus forming a tangle of branched fibers and a structure that presents some thermo-mechanical properties similar to the ones of plastics. The aim of the present study was the selection of the optimal inoculation temperature, light, humidity and the best substrate for the fastest and consistent mycelium growth. Four types of mycelium were incubated, namely Pleurotus ostreatus (382), Hypsizygus ulmarius (420), Ganoderma lucidum (560) and Trametes versicolor (620). The influence of the three substrates (coffee grounds, pine waste and general wood waste) on the growth was analyzed both morphologically and thermo-mechanically by means of differential scanning calorimetry (DSC) and X-ray micro computed tomography (microCT).
- Occurrence of tet(O/M/O) mosaic gene in tetracycline-resistant CampylobacterPublication . Hormeño, Lorena; Campos, Maria J.; Vadillo, Santiago; Quesada, AlbertoCampylobacter is one of the most important microorganisms responsible for foodborne diseases in the EU. In this study, we investigated resistance to tetracycline in 139 Campylobacter jejuni and Campylobacter coli samples isolated from human clinical cases. From these, 110 were resistant to tetracycline, with MIC (minimal inhibitory concentration) varying in a range of 1 to >512 ug/mL, and 109 (78.4%) carried tet(O), a gene that confers resistance to tetracycline through the expression of a protein that confers protection to the ribosome. Amongst the tetracycline-resistant isolates, one C. jejuni (HCC30) was the only tet(O)-negative sample, presenting an MIC of 256 ug/mL. Instead, the mosaic gene tet(O/M/O) was found in HCC30 and, as far as we know, this is the first description of this chimeric gene originating from homologous recombination between tet(O) and tet(M). The previously described mosaic gene tet(O/32/O), also found in Campylobacter, presents a chimeric structure very similar to that of tet(O/M/O), affecting domains II and III of encoded proteins distantly related to the elongation factor G (EF-G). The tet(O/M/O) mosaic gene has been found in nucleotide databases in several genomes of Campylobacter isolated from different origins, indicating its frequent acquisition, even though it can be undetected through screening by PCR with specific tet(O) primers. In this work, we address the improvement of classical PCR to effciently diagnose the most prevalent tetracycline resistance determinants in Campylobacter, including tet(O/M/O), which should be taken into account in the optimization of campylobacteriosis treatments.
- Physicochemical and nutritional profile of leaves, flowers, and fruits of the edible halophyte chorão-da-praia (Carpobrotus edulis) on Portuguese west shoresPublication . Neves, Marta; Antunes, Madalena; Fernandes, Wilson; Azevedo, Zélia M.; Freitas, Victor; Rocha, João M.; Tecelão, Carla; Campos, Maria J.Leaves, flowers and fruits from the edible halophyte chorão-da-praia (Carpobrotus edulis), harvested in the Portuguese western sea shores, were characterized regarding their proximate composition, fatty acid profile, pigments, phenolic compounds, antioxidant and antimicrobial activities. Fruits had the highest amount of carbohydrates (70.2 ± 1.6%) and the lowest of protein (4.67 ± 0.22%) and ash (22.0 ± 1.0%) contents. No significant differences were observed in the lipid fraction. Leaves were mainly constituted by saturated (52.6 ± 1.3%) fatty acids (FA), whereas fruits showed the highest amount of polyunsaturated FA (48.6 ± 3.1%). Chlorophylls and carotenoids were more abundant in leaves. Aqueous-ethanolic (1:1, v/v) extract of flowers exhibited the highest phenolic content (299 ± 8 μg/mg of gallic acid equivalents), by the Folin–Ciocalteu methodology, as well as the strongest antioxidant activity (IC50 = 11.83 ± 1.0 μg/mL and 7.82 ± 0.24 μmol/mg of ascorbic acid equivalents by the DPPH and FRAP methods, respectively). Also, flowers extract showed the most pronounced antimicrobial activity by the microtiter broth dilution method. Mass and tandem mass spectra revealed that the most abundant species in all extracts were glycosylated and/or acetylated O-Methyl flavonols, mainly derived from syringetin and laricitrin. Nuclear magnetic resonance was also employed for complementary confirmation of the syringetin moieties. Regarding the profile in polyphenols, when comparing leaves, flowers and fruits, one concluded that there were clearly differences in the relative amount of these polyphenols, being flowers richer in the syringetin derivatives. In conclusion, this edible plant, classified as an invasive species of the Portuguese coast, highlights for its richness in bioactive compounds with potential application in the food industry.
- A pilot plant scale testing of the application of seaweed-based natural coating and modified atmosphere packaging for shelf-life extension of fresh-cut applePublication . Augusto, Ana; Miranda, Andreia; Costa, Leonor; Pinheiro, Joaquina; Campos, Maria J.; Raimundo, Délio; Pedrosa, Rui; Mitchell, Geoffrey; Niranjan, Keshavan; Silva, Susana F.J.Codium tomentosum hydroethanolic extract was obtained using a pilot solid–liquid extractor to validate the anti-browning functionality of the extract under industrial conditions. Fresh-cut apple slices were coated by immersion in: (1) a seaweed extract solution (0.5% w/v) and (2) a commercial coating, and the two sets of samples were compared with a control (immersion in water). Packaged samples were stored, under ambient and modified atmosphere conditions at 4°C. After 30 days of storage, the samples that were coated with the seaweed extract and packaged under modified atmosphere, demonstrated lower peroxidase activity and polyphenol oxidation when compared with the samples treated with the commercial additive. These results confirm, at pilot scale and under industrial production conditions, the efficacy of the seaweed extract as a bio-based substitute for the synthetic coatings, which are currently used to prevent browning in fresh-cut apples.
- A pilot plant scale testing of the application of seaweed-based natural coating and modified atmosphere packaging for shelf-life extension of fresh-cut applePublication . Augusto, Ana; Miranda, Andreia; Costa, Leonor; Pinheiro, Joaquina; Campos, Maria J.; Raimundo, Délio; Pedrosa, Rui; Mitchell, Geoffrey; Niranjan, Keshavan; Silva, Susana F. J.Codium tomentosum hydroethanolic extract was obtained using a pilot solid–liquid extractor to validate the anti-browning functionality of the extract under industrial conditions. Fresh-cut apple slices were coated by immersion in: (1) a seaweed extract solution (0.5% w/v) and (2) a commercial coating, and the two sets of samples were compared with a control (immersion in water). Packaged samples were stored, under ambient and modified atmosphere conditions at 4°C. After 30 days of storage, the samples that were coated with the seaweed extract and packaged under modified atmosphere, demonstrated lower peroxidase activity and polyphenol oxidation when compared with the samples treated with the commercial additive. These results confirm, at pilot scale and under industrial production conditions, the efficacy of the seaweed extract as a bio-based substitute for the synthetic coatings, which are currently used to prevent browning in fresh-cut apples. Novelty impact statement Fresh-cut fruits are subjected to processing operations leading to a decrease in nutritional and organoleptic properties. It is therefore necessary to adopt strategies to delay the degradative processes. In this study, the efficacy of a pilot-scale production and industrial application of a coating formulated with Codium tomentosum seaweed extract has been established for the first time. This seaweed extract possesses the potential to prevent browning development in fresh-cut apples under industrial operating conditions.
- Preservation of fresh-cut Rocha Pear using Codium tomentosum extractPublication . Augusto, Ana; Miranda, Andreia; Crespo, Daniel; Campos, Maria J.; Raimundo, Délio; Pedrosa, Rui; Mitchell, Geoffrey; Niranjan, Keshavan; Silva, Susana F.J.Rocha is a Portuguese pear cultivar with high economic importance in the Portuguese Western Region. Degradative processes following its manipulation can quickly lead to product rejection, especially when sold as a freshcut product. The efficacy of a marine-based edible coating to inhibit superficial browning development in freshcut Rocha pear slices was investigated over a storage period of 15 days. The aqueous extract of Codium tomentosum, an edible green seaweed, was incorporated in an edible coating (0.5 g 100 mL -1) for fresh-cut Rocha pear. This novel treatment effect on the quality parameters of the pears was compared with a commercial coating currently used by industry and a control (dipping in deionised water). After 15 days storage at 4 ◦C, samples treated with the seaweed extract exhibited fewer colour changes and lower rates of superficial browning than control and commercial samples. Seaweed extract treatment was also observed to inhibit yeast and mould development, which may further contribute to shelf-life extension.