Olhão, Portugal
Olhão, Portugal
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Navarro-Guillen C.,Institute Ciencias Marinas Of Andalucia Icman Csic | Engrola S.,University of Algarve | Castanheira F.,University of Algarve | Bandarra N.,IPMA | And 4 more authors.
Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology | Year: 2013

Lipid nutrition of marine fish larvae has focused on supplying essential fatty acids (EFA) at high levels to meet requirements for survival, growth and development. However, some deleterious effects have been reported suggesting that excessive supply of EFA might result in insufficient supply of energy substrates, particularly in species with lower EFA requirements such as Senegalese sole (Solea senegalensis). This study addressed how the balance between EFA and non-EFA (better energy sources) affects larval performance, body composition and metabolism and retention of DHA, by formulating enrichment emulsions containing two different vegetable oil sources (olive oil or soybean oil) and three DHA levels. DHA positively affected growth and survival, independent of oil source, confirming that for sole post-larvae it is advantageous to base enrichments on vegetable oils supplying higher levels of energy, and supplement these with a DHA-rich oil. In addition, body DHA levels were generally comparable considering the large differences in their dietary supply, suggesting that the previously reported {increment}4 fatty acyl desaturase (fad) operates in vivo and that DHA was synthesized at physiologically significant rates through a mechanism involving transcriptional up-regulation of {increment}4fad, which was significantly up-regulated in the low DHA treatments. Furthermore, data suggested that DHA biosynthesis may be regulated by an interaction between dietary n-. 3 and n-. 6 PUFA, as well as by levels of LC-PUFA, and this may, under certain nutritional conditions, lead to DHA production from C18 precursors. The molecular basis of putative fatty acyl {increment}5 and {increment}6 desaturation activities remains to be fully determined as thorough searches have found only a single ({increment}4) Fads2-type transcript. Therefore, further studies are required but this might represent a unique activity described within vertebrate fads. © 2013 Elsevier Inc.

Hernandez-Molina F.J.,Royal Holloway, University of London | Stow D.A.V.,Heriot - Watt University | Alvarez-Zarikian C.A.,Texas A&M University | Acton G.,Sam Houston State University | And 32 more authors.
Science | Year: 2014

Sediments cored along the southwestern Iberian margin during Integrated Ocean Drilling Program Expedition 339 provide constraints on Mediterranean Outflow Water (MOW) circulation patterns from the Pliocene epoch to the present day. After the Strait of Gibraltar opened (5.33 million years ago), a limited volume of MOW entered the Atlantic. Depositional hiatuses indicate erosion by bottom currents related to higher volumes of MOW circulating into the North Atlantic, beginning in the late Pliocene. The hiatuses coincide with regional tectonic events and changes in global thermohaline circulation (THC). This suggests that MOW influenced Atlantic Meridional Overturning Circulation (AMOC), THC, and climatic shifts by contributing a component of warm, saline water to northern latitudes while in turn being influenced by plate tectonics.

PubMed | IPMA, CNR Institute of Neuroscience, Brown University, University of Florida and 94 more.
Type: | Journal: GigaScience | Year: 2015

Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the worlds oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits.

Gutscher M.-A.,French National Center for Scientific Research | Dominguez S.,Montpellier University | Westbrook G.K.,University of Birmingham | Le Roy P.,French National Center for Scientific Research | And 8 more authors.
Tectonophysics | Year: 2012

The Gibraltar arc, spans a complex portion of the Africa-Eurasia plate boundary marked by slow oblique convergence and intermediate and deep focus seismicity. The seemingly contradictory observations of a young extensional marine basin surrounded by an arcuate fold-and-thrust belt, have led to competing geodynamic models (delamination and subduction). Geophysical data acquired in the past decade provide a test for these models and support a narrow east-dipping, subduction zone. Seismic refraction studies indicate oceanic crust below the western Gulf of Cadiz. Tomography of the upper mantle reveals a steep, east-dipping high P-wave velocity body, beneath Gibraltar. The anisotropic mantle fabric from SKS splitting shows arc-parallel "fast directions", consistent with toroidal flow around a narrow, westward retreating subducting slab. The accompanying WSW advance of the Rif-Betic mountain belt has constructed a thick pile of deformed sediments, an accretionary wedge, characterized by west-vergent thrust anticlines. Bathymetric swath-mapping images an asymmetric embayment at the deformation front where a 2. km high basement ridge has collided. Subduction has slowed significantly since 5. Ma, but deformation of recent sediments and abundant mud volcanoes suggest ongoing activity in the accretionary wedge. Three possible origins for this deformation are discussed; gravitational spreading, overall NW-SE convergence between Africa and Iberia and finally a WSW tectonic push from slow, but ongoing roll-back subduction. In the absence of arc volcanism and shallow dipping thrust type earthquakes, evidence in favor of present-day subduction can only be indirect and remains the object of debate. Continued activity of the subduction offers a possible explanation for great (M. >. 8.5) earthquakes known to affect the area, like the famous 1755 Great Lisbon earthquake. Recent GPS studies show SW motion of stations in N Morocco at velocities of 3-6. mm/yr indicating the presence of an independent block, a "Rif-Betic-Alboran" microplate, situated between Iberia and Africa. © 2012 Elsevier B.V.

Morais S.,IRTA - Institute of Agricultural-Alimentary Research and Technology | Mendes A.C.,IPMA | Castanheira M.F.,University of Algarve | Coutinho J.,IPMA | And 6 more authors.
Aquaculture | Year: 2014

Senegalese sole is considered a species with high interest for aquaculture diversification in the South of Europe whose production has shown an important increase in recent years. However, broodstock nutrition of this species is still based on a diet of fresh feeds, which poses important sanitary risks, has variable supply and nutritional composition and contributes to the deterioration of water quality. This study was performed to test two new specifically formulated semi-moist diets for Solea senegalensis broodstock: a control diet (CTR) formulated with high quality ingredients and a further supplemented diet (PLUS), fortified with lipids, vitamins and long-chain polyunsaturated fatty acids (LC-PUFA), mainly DHA. Larvae originating from simultaneous spawns of both broodstock groups were reared in the same standard conditions up to 67. days post-hatching (dph) and effects were assessed on early ontogeny (up to first-feeding), larval (up to 17. dph) and juvenile performance. Both diets led to the production of eggs with good viability, hatching rate and fatty acid composition. The fatty acid profile reflected differences in the experimental diets, with eggs from the PLUS group presenting higher levels of both EPA and DHA, although more markedly for EPA. Furthermore, significant differences in the percentage of EPA were maintained until 7. dph, while DHA was only significantly higher in eggs and 0. dph larvae from the PLUS treatment. The expression of enzymes of the LC-PUFA biosynthesis pathway was assessed in parallel and results show that transcript levels of elovl5 and δ4fad in eggs and newly hatched larvae were affected by broodstock diet and that DHA biosynthesis capacity of Senegalese sole larvae may have been up-regulated at hatching in the CTR treatment. Further nutrient supplementation in the PLUS diet did not enhance larval survival and performance and larvae originating from this treatment were significantly smaller than their CTR counterparts at hatching and 3. dph and had lower growth up to 17. dph, probably reflecting variations in egg size between batches. However, after metamorphosis, post-larvae from the PLUS treatment quickly caught-up and after complete weaning were significantly larger than juveniles originating from the CTR broodstock. Furthermore, juveniles from the PLUS treatment had a much lower incidence of tail fin deformity. These results were surprising and should be further investigated as, although we cannot exclude a genetic effect, the results could also indicate a nutritional programming effect of broodstock diet in sole juvenile growth and quality. In addition, the results suggest that Senegalese sole larvae are capable of regulating DHA biosynthesis as early as at hatching to counterbalance lower levels of DHA in eggs. Finally, we demonstrate that the current feeding protocol of sole broodstock can be replaced by a safer formulated semi moist diet with good results. © 2014 Elsevier B.V.

PubMed | IPMA, University of Algarve and French Research Institute for Exploitation of the Sea
Type: | Journal: General and comparative endocrinology | Year: 2016

Sperm cryopreservation is a widely employed technique that promotes alternative techniques to contribute to broodstock management or restoration programs for species of commercial interest, endangered species or species with an interesting genotype. The preservation of genetic material from improved stocks or from the original population is extremely important for the oyster aquaculture industry to prevent the potential impacts of epidemic diseases and natural disasters. The Portuguese oyster, Crassostrea angulata, was the most important species commercialized by the shellfish industry. However, inadequate management of this industry and pathology occurrences resulted in a significant decrease in natural populations. For this reason, in this work a successful sperm cryopreservation protocol for this important species has been developed for the first time. Different internal cryoprotectants (DMSO, ethylene glycol, polyethylene glycol and methanol) at several concentrations (5, 10, 20%), containers (straws vs cryovials) and freezing rates (slow and fast rates) were tested. Cryoprotectant toxicity tests corroborated that this assay did not take into account the following steps of cryopreservation protocol as sperm agglutination. A fast freezing rate of cells diluted in10% DMSO and the use of straws as containers were the best cryopreservation conditions for Portuguese oyster sperm. Finally, fertilization assays confirmed the efficiency of the cryopreservation protocol in oyster sperm. These results demonstrated that different susceptibilities have been detected concerning sperm cryopreservation depending on oyster species or genetic material composition.

Teixeira De Sousa J.,French National Center for Scientific Research | Milan M.,University of Padua | Bargelloni L.,University of Padua | Pauletto M.,University of Padua | And 6 more authors.
PLoS ONE | Year: 2014

The European clam, Ruditapes decussatus is a species with a high commercial importance in Portugal and other Southern European countries. Its production is almost exclusively based on natural recruitment, which is subject to high annual fluctuations. Increased knowledge of the natural reproductive cycle of R. decussatus and its molecular mechanisms would be particularly important in providing new highly valuable genomic information for better understanding the regulation of reproduction in this economically important aquaculture species. In this study, the transcriptomic bases of R. decussatus reproduction have been analysed using a custom oligonucleotide microarray representing 51,678 assembled contigs. Microarray analyses were performed in four gonadal maturation stages from two different Portuguese wild populations, characterized by different responses to spawning induction when used as progenitors in hatchery. A comparison between the two populations elucidated a specific pathway involved in the recognition signals and binding between the oocyte and components of the sperm plasma membrane. We suggest that this pathway can explain part of the differences in terms of spawning induction success between the two populations. In addition, sexes and reproductive stages were compared and a correlation between mRNA levels and gonadal area was investigated. The lists of differentially expressed genes revealed that sex explains most of the variance in gonadal gene expression. Additionally, genes like Foxl2, vitellogenin, condensing 2, mitotic apparatus protein p62, Cep57, sperm associated antigens 6, 16 and 17, motile sperm domain containing protein 2, sperm surface protein Sp17, sperm flagellar proteins 1 and 2 and dpy-30, were identified as being correlated with the gonad area and therefore supposedly with the number and/or the size of the gametes produced. © 2014 Teixeira De Sousa et al.

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