Unidade de Investigação - MARE – Marine and Environmental Sciences Centre
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- Carica papaya latex: A low‐cost biocatalyst for human milk fat substitutes productionPublication . Tecelão, Carla; Rivera, Ivanna; Sandoval, Georgina; Ferreira‐Dias, SuzanaAbstractThis work aims at evaluating the potential of Carica papaya lipase (CPL) self‐immobilized in papaya latex as a biocatalyst for the synthesis of human milk fat substitutes (HMFS), to be used as a low‐cost alternative to commercial lipases. Two different CPL preparations, one extracted from the papaya fruit (CPL I) and the other from petiole leaves (CPL II) of papaya tree, were tested as catalysts for the acidolysis between tripalmitin and (i) oleic acid or (ii) omega‐3 PUFA, batchwise, at 60°C, in solvent‐free media. After 24 h, molar incorporation was higher for oleic acid (22.1 mol%) when CPL I was used. This biocatalyst was selected for further studies. RSM was used to model reaction conditions: medium formulation (molar ratio oleic acid/tripalmitin, MR, 1.2:1–6.8:1) and temperature (58–72°C). Acyl migration decreased with MR increase. In batch operational stability assays at 60°C, using MR of 2:1 and 6:1, the highest stability was observed for a MR of 2:1.Practical applications: The use of this biocatalyst is a feasible way to valorize papaya agro‐residues which represent an important environmental problem in the producing countries. The obtained results were rather promising since, with this almost zero‐cost biocatalyst, it was possible to produce a high added‐value product (HMFS). Under optimized conditions, the obtained results were comparable with those obtained with expensive immobilized commercial lipases.
- Detection of QnrB54 and Its Novel Genetic Context in Citrobacter freundii Isolated from a Clinical CasePublication . Campos, Maria Jorge; Palomo, Gonzalo; Hormeño, Lorena; Rodrigues, Américo; Sánchez-Benito, Rosario; Píriz, Segundo; Quesada, AlbertoLETTER Quinolone resistance in Enterobacteriaceae is mediated by mutations in the quinolone resistance-determining regions (QRDR) of topoisomerase genes and/or by plasmid-mediated quinolone resistance determinants (PMQR) such as the qnr genes encoding pentapeptide repeat proteins (1). The qnrB family is represented by 80 different alleles (http://www.lahey.org/qnrStudies/); most of them originated from Citrobacter strains and spread to other Enterobacteriaceae species (2). This work describes the identification of a new allele of the quinolone resistance protein QnrB, QnrB54, in a human clinical isolate of Citrobacter freundii detected in Spain.
- Developmental Toxicity of Endocrine Disrupters Bisphenol A and Vinclozolin in a Terrestrial IsopodPublication . Lemos M.F.L.; van Gestel, C. A. M.; Soares, A. M. V. M.Studies of the effects of endocrine-disrupting compounds (EDCs) on invertebrates are still largely underrepresented. This work aims to fill this gap by assessing the effects of bisphenol A (BPA) and vinclozolin (Vz) on the terrestrial isopod Porcellio scaber (common rough woodlouse). Male adult and sexually undifferentiated juvenile woodlice were exposed to the toxicants. Effects on molting regime and growth were investigated independently for males and female woodlice after sexual differentiation. Both chemicals elicited developmental toxicity to P. scaber by causing overall decreased growth. Nevertheless, BPA induced molting, whereas Vz delayed it. Although the LC 50 values for juvenile and adult survival were fairly similar, juvenile woodlice showed an increased chronic sensitivity to both chemicals, and female woodlice were most the sensitive to BPA. We recommend the use of adults, juveniles, female, and male woodlice, as well as a large range of toxicant concentrations, to provide valuable information regarding differential dose responses, effects, and threshold values for EDCs.
- Effect of stocking density and different diets on growth of Percula Clownfish, Amphiprion percula (Lacepede, 1802)Publication . Chambel, João; Severiano, Vera; Baptista, Teresa; Mendes, Susana; Pedrosa, RuiThe aim of this study was to evaluate the influence of stocking density (0.5, 1, 2 and 3 fishL−1) and commercial marine fish diets (diet A, B, C and D) over four months on specific growth rate, condition factor, percentage without anomalous pigmentation (partial or total lack of white bands -miss-band) and survival of juvenile Amphiprion percula. Results showed that at 0.5 fishL−1 densities induced the best survival (100%) and also the maximum percentage of fish without miss-band (58.33 +/−4.417%). The maximum SGR was obtained for the 0.5 fishL−1 (0.459 ± 0.023% cm/day). However, the best condition factor (2.53 +/− 0.27) was achieved for 2 fishL−1 densities. There were no significant differences in survival (68.9 to 84.5%), fish without miss-bands (18.03 to 26.92%) and condition factor (1.92 to 2.1) among diets during the experimental period. On the other hand, diet C (with 41% crude protein) supported the best SGR (0.485 ± 0.001% cmday−1). The results suggested that stocking density are critical and more relevant when compared with the different diet tested, namely on specific growth rate, condition factor, the miss-band and survival of juvenile percula clownfish. This study has particular significance with regards to anemonefishes husbandry in terms of survival and production efficiency.
- Evaluating the Potential of the Defatted By-Product of Aurantiochytrium sp. Industrial Cultivation as a Functional FoodPublication . Reboleira, João; Félix, Rafael; Félix, Carina; Melo, Marcelo M. R. de; Silva, Carlos M.; Saraiva, Jorge A.; Bandarra, Narcisa M.; Teixeira, Bárbara; Mendes, Rogério; Paulo, Maria C.; Coutinho, Joana; Lemos, Marco F. L.While Aurantiochytrium sp. is an increasingly popular source of polyunsaturated fatty acids (PUFAs), its extraction generates high amounts of waste, including the spent, defatted residue. The composition and bioactivities of this by-product could prove to be a major part of the sustainable valorisation of this organism within the framework of a circular economy. In this study, the defatted biomass of commercial Aurantiochytrium sp. was nutritionally characterised, and its amino acid profile was detailed. Additionally, the antioxidant and prebiotic potentials of an enzymatically digested sample of defatted Aurantiochytrium sp. were evaluated under a set of miniaturised in vitro assays. The nutritional profile of the spent Aurantiochytrium biomass revealed a protein and dietary-fibre rich product, with values reaching 26.7% and 31.0% for each, respectively. It also held high concentrations of glutamic and aspartic acid, as well as a favourable lysine/arginine ratio of 3.73. The digested samples demonstrated significant Weissela cibaria and Bifidobacterium bifidum growth-enhancing potential. Residual ferric reducing antioxidant power (FRAP) activity was likely attributed to antioxidant amino acids or peptides. The study demonstrated that some of the nutritional and functional potential that reside in the defatted Aurantiochytrium sp. waste encourages additional studies and the development of food supplements employing this resource’s by-products under a biorefinery framework.
- Growth Performance after Agouti-Signaling Protein 1 (Asip1) Overexpression in Transgenic ZebrafishPublication . Godino-Gimeno, Alejandra; Sánchez, Elisa; Guillot, Raúl; Rocha, Ana; Angotzi, Anna Rita; Leal, Esther; Rotllant, Josep; Cerdá-Reverter, José MiguelThe melanocortin system is a key structure in the regulation of energy balance. Overexpression of inverse agonists, agouti-signaling protein (ASIP), and agouti-related protein (AGRP) results in increased food intake, linear growth, and body weight. ASIP regulates dorsal-ventral pigment polarity through melanocortin 1 receptor (MC1R) and overexpression induces obesity in mice by binding to central MC4R. Asip1 overexpression in transgenic zebrafish (asip1-Tg) enhances growth, yet experiments show fish overexpressing Asip1 do not develop obesity even under severe feeding regimes. Asip1-Tg fish do not need to eat more to grow larger and faster; thus, increased food efficiency can be observed. In addition, asip1-Tg fish reared at high density are able to grow far more than wild-type (WT) fish reared at low density, although asip1-Tg fish seem to be more sensitive to crowding stress than WT fish, thus making the melanocortin system a target for sustainable aquaculture, especially as the U.S. Food and Drug Association has recently approved transgenic fish trading.
- Herbivory drives kelp recruits into ‘hiding’ in a warm ocean climatePublication . Franco, João N.; Wernberg, Thomas; Bertocci, Iacopo; Duarte, Pedro; Jacinto, David; Tuya, Fernando; Vasco Rodrigues, NunoAssessing effects of herbivory across broad gradients of varying ocean climate conditions and over small spatial scales is crucial for understanding its influence on primary producers. Effects of herbivory on the distribution and abundance of kelp recruits were examined experimentally at two regions under contrasting ocean climate. Specifically, the abundance and survivorship of kelp recruits and the abundance of macro-herbivores were compared between a 'cool' and a 'warm' region in northern and central Portugal, respectively. In each region, the abundance of kelp recruits and the intensity of grazing were compared between habitats of different topography within reefs (open reef vs. crevices). Compared to the 'warm' region, the abundance of kelp recruits was 3.9 times greater in the 'cool' region, where 85% of recruits were found in open reef habitats. In contrast, 87% of recruits in the 'warm' region were restricted to crevices. The 'warm' region had 140 times greater abundances of sea urchins, 45 times more herbi vorous fish and 4.1 times more grazing marks on kelp recruits than the 'cool' region. Grazing assays showed ca. 50 times higher rates of kelp biomass consumption, mainly by fishes, and zero survivorship of kelp recruits in the 'warm' relative to the 'cool' region. This study suggests both temperature and herbivores affect abundances of kelp recruits across latitudes, and demonstrates how herbivores affect their distribution at local scales, driving kelp recruits into 'hiding' in crevices under intense herbivory. Consequently, where net recruitment success is compromised by herbivory, the persistence of kelps will be contingent on availability of topographical refuges.
- Historical separation and present-day structure of common dolphinfish (Coryphaena hippurus) populations in the Atlantic Ocean and Mediterranean SeaPublication . Maggio, Teresa; Allegra, Alessandro; Andaloro, Franco; Barreiros, João Pedro; Battaglia, Pietro; Butler, Christopher M; Cuttitta, Angela; Fontes, Miguel Rodrigues Jorge; Freitas, Rui; Gatt, Mark; Karakulak, F Saadet; Macias, David; Nicosia, Aldo; Oxenford, Hazel A; Saber, Samar; Yildiz, Taner; Sinopoli, Mauro; Vasco Rodrigues, Nuno; Grant, W StewartThe common dolphinfish (Coryphaena hippurus) is an epipelagic, mid-trophic level, highly migratory species distributed throughout the world’s tropical and subtropical oceans in waters greater than 20C. Life-history variables, migratory behaviour, and genetic markers have been used to define major stocks in the central Atlantic Ocean and Mediterranean Sea. Here, we used the mitochondrial DNA gene NADH subunit 1 (688 bp) to test for differences between population groups. A total of 103 haplotypes were detected among 203 fish. Gene diversities in samples were large and similar among populations (mean h ¼ 0.932; range 0.894–0.987), but nucleotide diversities varied widely among samples (range p ¼ 0.004–0.034) and appear to reflect population histories. Principal component analysis revealed two large populations groups, and the analysis of molecular variation and pairwise values of UST resolved population structure within these groups. Populations in the eastern Atlantic and Mediterranean showed the largest amounts of divergence from one another (UCT ¼ 0.331). Adult movement and biophysical barriers to larval dispersal may explain contemporary differences between stocks, but the divergent populations in the Mediterranean Sea are likely due to isolations by cold temperature barriers during Pleistocene glaciations. The geographically large stock groupings require international cooperation in the harvest management and conservation of local dolphinfish population
- Mono-specific facies of Parazoanthus axinellae in Luiz Saldanha Marine ParkPublication . Gomes-Pereira, J.N.; Vasco-Rodrigues, N.; Afonso, A.; Albuquerque, M.; Berecibar, E.; Bernardes, L.; Calado, A.; Castanheira, A.; Tojeira, I.; Tempera, Fernando; Dias, F.C.; Santos, R.S.; Campos, A.S.We report the first mono-specific facies ofParazoanthus axinellaefrom the western Portuguese coast. The habitat was recorded using a MiniRov Observer on a large outcrop at ca. 55–60 m in the Luiz Saldanha Marine Park. A method to estimate the maximum uncertainty of the ROV position is illustrated and the occurrence of the facies is discussed.
- Production of human milk fat substitutes enriched in omega-3 polyunsaturated fatty acids using immobilized commercial lipases and Candida parapsilosis lipase/acyltransferasePublication . Tecelão, Carla; Silva, Joana; Dubreucq, Eric; Ribeiro, Maria H.; Ferreira-Dias, SuzanaIn human milk fat (HMF), palmitic acid (20-30%), the major saturated fatty acid, is mostly esterified at the sn-2 position of triacylglycerols, while unsaturated fatty acids are at the sn-1,3 positions, conversely to that occurring in vegetable oils. This study aims at the production of HMF substitutes by enzyme-catalyzed interesterification of tripalmitin with (i) oleic acid (system I) or (ii) omega-3 polyunsaturated fatty acids (omega-3 PUFA) (system II) in solvent-free media. Interesterification activity and batch operational stability of commercial immobilized lipases from Rhizomucor miehei (Lipozyme RM IM), Thermomyces lanuginosa (Lipozyme TL IM) and Candida antarctica (Novozym 435) from Novozymes, DK, and Candida parapsilosis lipase/acyltransferase immobilized on Accurel MP 1000 were evaluated. After 24-h reaction at 60 °C, molar incorporation of oleic acid was about 27% for all the commercial lipases tested and 9% with C. parapsilosis enzyme. Concerning omega-3 PUFA, the highest incorporations were observed with Novozym 435 (21.6%) and Lipozyme RM IM (20%), in contrast with C. parapsilosis enzyme (8.5%) and Lipozyme TL IM (8.2%). In system I, Lipozyme RM IM maintained its activity for 10 repeated 23-h batches while for Lipozyme TL IM, Novozym 435 and C. parapsilosis enzyme, linear (half-life time, t1/2 = 154 h), series-type (t1/2 = 253 h) and first-order (t1/2 = 34.5 h) deactivations were respectively observed. In system II, Lipozyme RM IM showed linear deactivation (t1/2 = 276 h), while Novozym 435 (t1/2 = 322 h) and C. parapsilosis enzyme (t1/2 = 127 h), presented series-type deactivation. Both activity and stability of the biocatalysts depended on the acyl donor used.