Mostrando recursos 1 - 20 de 506

  1. Regeneration in Zebrafish (Danio rerio) fins: pattern of expression of mineralization–related Gla proteins

    Brito, A. B.; Gavaia, Paulo J.; Cancela, Leonor
    Teleost fishes have the exceptional ability to largely regenerate severed appendages comprising several different tissues. Fin regeneration starts through the formation of heterogeneous mesenchyma-like cells, named blastema, and located between stump tissues and the wounded epidermis. This event, denominated epimorphic regeneration, comprises strict growth control and cell reprogramming leading to faithful restoration of the lost parts. Matrix Gla Protein (Mgp) and Bone Gla Protein (Bgp, osteocalcin) are small extracellular matrix Gla proteins, members of the vitamin K-dependent (VKD) family.

  2. Rearing fish larvae for extensive and semi-intensive aquaculture - the “natural” mesocosms system

    Cunha, M. E.; Quental-Ferreira, H.; Boglione, C.; Palamara, E.; Gavaia, Paulo J.; Pousão-Ferreira, P.
    Non-intensive aquaculture systems are rapidly generating interest due to increased awareness of consumers about environmental issues, including those associated with coastal areas; eutrophication as a result of intensive aquaculture production is seen as a problem, there is concern about animal welfare issues in fish rearing, and food safety is of course a major concern.

  3. Identificação de Malformações Esqueléticas em Peixes

    Gavaia, Paulo J.
    - Monitorizar e identificar as principais malformações que ocorrem em peixes produzidos em aquacultura intensiva. Desenvolver estudos em conjunto com empresas da região para relacionar (1) condições de cultivo (em particular factores nutricionais) e desenvolvimento esquelético, (2) relações genéticas entre reprodutores e progenia e tentar identificar possíveis causas genéticas para presença de larvas com deformações esqueléticas.

  4. Gla proteins as markers for studies of skeletal development and malformations in new aquaculture fish species (Pagrus auriga, Diplodus sargo and Scophtalmus maximus)

    Viegas, C. S. B.; Gavaia, Paulo J.; Ortiz-Delgado, J. B.; Sarasquete, C.; Cancela, Leonor
    Evaluation of the onset and the development of skeletal structures during larval ontogeny of commercially important species in southern Iberia Peninsula and Mediterranean area (...) is essential for the successful production of high quality fish.

  5. Factors enhancing fish sperm quality and emerging tools for sperm analysis

    Cabrita, E.; Martínez-Páramo, S.; Gavaia, Paulo J.; Riesco, M. F.; Valcarce, D. G.; Sarasquete, C.; Herráez, M. P.; Robles, V.
    With this review we try to give a comprehensive overview of the current methods used in research to assess sperm quality. In addition, we identify some of the most important factors for enhancing sperm production and quality, including, broodstock nutrition, epigenetics and sperm management (cryopreservation). Sperm quality can be assessed by analyzing different parameters fromsimplemethods to very sophisticated approaches involving molecular tools. Parameters related with sperm composition or function (e.g. spermatozoa plasma membrane lipids, seminal plasma composition,motility activation) have successfully characterized a spermsample but could not respond to the causes behind sperm defects. Reactive oxygen species (ROS) are one of the causes of the impairment of sperm...

  6. Comparative analysis of gene expression profiles among distantly related fish species. Insight into skeletal and immunological systems

    Mariani, Valentina; Viegas, C. A.; Gavaia, Paulo J.; Cancela, Leonor; Giuffra, Elisabetta
    The aim of this project is to identify and characterize the polymorphism of genes relevant for the physiology of skeletal and immunological tissues, and highly conserved across fish species. To achieve this goal, the expression profiles of an ancient species relevant for caviar and fillet production(A. transmontanus) are compared to available and in progress information (Marine Genomics network of Excellence, UE) of modern Teleosts.

  7. Programming the metabolic gene expression in zebrafish juveniles (Danio rerio) by supra-physiological glucose level during embryogenesis

    Rocha, F.; Dias, J.; Engrola, S.; Gavaia, Paulo J.; Geurden, I.; Dinis, Maria Teresa; Panserat, S.
    Using zebrafish as a model organism, assess the effect of high glucose levels during early embryonic stages as a lifelong moderator of metabolic pathways.

  8. Spectroscopic characterization of a novel 2×[4Fe–4S] ferredoxin isolated from Desulfovibrio desulfuricans ATCC 27774

    Rodrigues, Pedro; Moura, Isabel; Macedo, Anjos L.; Moura, José J. G.
    A novel iron /sulfur containing protein, a ferredoxin (Fd), was purified to homogeneity from the extract of Desulfovibrio desulfuricans American type culture collection (ATCC) 27774. The purified protein is a 13.4 kDa homodimer with a polypeptide chain of 60 amino acids residues, containing eight cysteines that coordinate two [4Fe /4S] clusters. The protein is shown to be air sensitive and cluster conversions take place. We structurally characterize a redox state that contains two [4Fe /4S] cores. 1D and 2D 1H NMR studies are reported on form containing the clusters in the oxidized state. Based on the nuclear Overhauser effect (NOE), relaxation...

  9. Effect of antiprotozoal drugs on the proliferation of the bivalve parasite Perkinsus olseni

    Elandalloussi, Laurence M.; Leite, Ricardo B.; Rodrigues, Pedro; Afonso, Ricardo; Nunes, Patrícia A.; Cancela, Leonor
    The protozoan parasite Perkinsus olseni causes severe losses among Ruditapes decussatus clams. The development of an in vitro culture of this parasite together with the use of a proliferation assay has provided the opportunity to screen for drug sensitivity of this parasite. Xenobiotics known for their antimalarial and antiprotozoal properties were tested against P. olseni. Only four of these drugs, namely cycloheximide, pyrimethamine, deferoxamine (DFO) and 2,2-bipyridyl (BIP), showed in vitro inhibitory effect on the parasite proliferation. Two in vivo experiments were designed to determine the effect of iron chelators on reducing P. olseni infection in clams. For this purpose, naturally infected...

  10. Influence of supplemental maslinic acid (olive-derived triterpene) on the post-mortem muscle properties and quality traits of gilthead seabream

    Matos, Elisabete; Silva, Tomé S.; Wulff, Tune; Valente, Luisa M. P.; Sousa, Vera; Sampaio, Eduardo; Gonçalves, Amparo; Silva, Joana M. G.; Dinis, Maria Teresa; Rodrigues, Pedro; Dias, J.
    Maslinic acid, a natural triterpene, was evaluated as a dietary supplement to modulate glycogen post-mortem mobilization in gilthead seabream muscle. For this purpose, a multidisciplinary trial was undertaken, where flesh quality criteria, as well as biochemical and histological parameters, enzymatic activities and protein expression in the muscle were assessed. Supplementing gilthead seabream diets with maslinic acid mainly resulted in hypertrophy of muscle fibres and inhibition of cathepsin B activity, with no observed differences in terms of glycogen and ATP content of the muscle, as well as glycogen phosphorylase activity. Proteomic analysis showed a low impact of maslinic acid supplementation on muscle...

  11. Photochemistry of 1-allyl-4-aryltetrazolones in solution; structural effects on photoproduct selectivity

    Ismael, A.; Serpa, C.; Cristiano, Maria Lurdes Santos
    The photochemistry of tetrazolones derived from the carbocyclic allylic alcohols cyclohex-2-enol and 3-methylcyclohex-2-enol and from the natural terpene alcohol nerol was investigated in solution with the aim of assessing the effect of solvent and of structural constraints imposed by bulky allylic moieties on photoproduct selectivity and stability. Photolysis of tetrazolones derived from nerol and cyclohex-2-enol afforded the corresponding pyrimidinones as major products through a pathway that appears to be similar to that proposed for other 1-allyl-4-phenyl-1,4-dihydro-5H-tetrazol-5-ones derived from acyclic and unhindered allylic alcohols previously investigated but photolysis of the tetrazolone derived from the bulkier 3–methylcyclohex-2-enol 4c leads to formation of a benzimidazolone, indicating...

  12. Vertebral deformities and local accumulation of gla proteins in sparus aurata

    Roberto, V.; Gavaia, Paulo J.; Cancela, Leonor
    Development of skeletal deformities is a frequent problem in Mediterranean fish aquaculture. Investigation of proteins involved in tissue calcification may help us uncover a possible correlation between the appearance of skeletal deformities and a defect in the site of expression and/or accumulation of a particular gene or protein. The purpose of this study was to investigate if the presence of skeletal deformities was related with any changes in the sites of osteocalcin (Oc or Bgp – Bone Gla Protein) and matrix Gla protein (Mgp) accumulation using immunohistochemistry methods.

  13. Two-dimensional proteomics as a tool to evaluate nutritional effects in farmed fish

    Richard, N.; Gavaia, Paulo J.; De Vareilles, M.; Silva, Tomé S.; Cordeiro, O.; Rodrigues, Pedro; Conceição, L. E. C.
    The use of proteomics in fish research is at a relatively early stage compared to terrestrial vertebrates. It has already been applied in the field of fish nutrition, enabling to point out metabolic changes occurring in response to dietary manipulations such as a variation in energy content, dietary nitrogen compostion, lipid composition or the incorporation of plant protein sources in aquafeeds.

  14. Skeletal quality in Senegalese sole: characterization of fish resulting from environmental and nutritional trials

    Gavaia, Paulo J.; Dionísio, G.; Cardeira, J.; Cunha, M. E.; Pousão-Ferreira, P.; Conceição, L. E. C.; Cancela, Leonor
    The Senegalese sole (Solea senegalensis) is characteristic from southern Europe and Mediterranean. It has recently been adapted for aquaculture production since it is well accepted by consumers and reaches high commercial values. After the initial description of the ontogenic events of skeletogenesis, systematic evaluation of the incidence of skeletal malformations by several groups revealed high levels of skeletal deformities reaching up to 90% of the population.

  15. Skeletal development and performance of zebrafish Danio rerio (Hamilton, 1822) larvae and juvenile fish fed with different diets

    Cardeira da Silva, J.; Dionísio, G.; Bensimon-Brito, A.; Cancela, Leonor; Gavaia, Paulo J.
    The appearance of skeletal deformities is a major problem associated to intensive, large-scale culture of fish species, affecting growth, development and ultimately, survival of produced fish. Although the mechanisms working behind it are still unclear, it is known that environmental, genetic and nutritional factors play fundamental roles. Given its importance as a vertebrate model to study skeleton-related diseases, the selection of an appropriate dietary protocol is a critical step in order to diminish the nutritional effect on bone and cartilage development.

  16. Skeletal development and bone-related gene expression in fish larvae

    Gavaia, Paulo J.; Cancela, Leonor
    The fish skeleton; skeletal malformations; skeletal malformations in mediterranean species; Types of skeletal malformations; Senegal sole skeletal development; Senegal sole skeletal deformities; Skeletal development in Danio rerio; ALP and TRAP in skeletal development; Skeletal development in Pagrus auriga; Time course of skeletal development in Pagrus auriga; Spatio-temporal pattern of bgp expression; bgp / mgp expression during development; In situ localization of zebrafish bgp mRNA;In situ localization of sole bgp mRNA; Immuno-detection of Bgp accumulation in zebrafish; Immuno-detection of Bgp accumulation in sole P.; In situ localization of zebrafish and sole mgp mRNA; Immuno-detection of MGP accumulation in zebrafish; Summary of zebrafish...

  17. Proteínas gla do osso e cartilagem: importância dos anfíbios e peixes como modelos biológicos para elucidação da sua função e evolução - gla proteins in bone and cartilage: the importance of fish and amphibian models to understand their function and evolution

    Cancela, Leonor; Laizé, Vincent; Simes, Dina; Gavaia, Paulo J.; Conceição, N.; Viegas, C. S. B.; Pombinho, A. R.; Marques, S.; Fidalgo, J.; Braga, D.
    Gla proteins, as the name indicates, undergo a post-translation modification where specific glutamic acid residues are γ-carboxylated through the action of the ubiquitous enzyme γ-carboxylase and using vitamin K as cofactor. Therefore, these proteins are also called vitamin K dependent proteins or VKD [1, 2]. We can assign VKDs to essentially four different groups: 1) those involved in blood coagulation (such as prothrombin and various coagulation factors; the first group to be discovered), 2) those involved in tissue mineralization (bone and matrix Gla proteins), 3) a nerve growth factor (gas6), and 4) those of unknown function (the latest group to be discovered). The carboxylase enzyme is...

  18. Identification of bone gla protein during early development of Solea Senegalensis

    Gavaia, Paulo J.; Faustino, M.; Cancela, Leonor
    With the objective of better understanding the calcification processus in the Sole (Solea senegalensis) we have followed the appearance of cartilage and bone structures during the sole early developmental stages (from hatching till 51 days post-Hatching-DPH) by a specific double labelling method (Alcin blue/Alizarin red).

  19. Fish as a model organism to study skeletal development and associated pathologies

    Gavaia, Paulo J.; Cancela, Leonor
    The physiological and molecular processes that regulate early cell differentiation and maturation, matrix deposition, morphogenesis and maintenance are under strict control during ontogenic skeletal development of vertebrates.

  20. Expression of the oligopeptide transporter PepT1 (Solute carrier family 15, member 1), in fed and starved larval Zebra fish (Danio rerio)

    Brito, A. B.; Rønnestad, I.; Gavaia, Paulo J.; Viegas, C. S. B.; Cancela, Leonor
    Fish embryos develop while utilizing yolk nutrients supplied by the (...). There normally exists a "first feeding window" between when the larvae (...) able to ingest exogenous feed,and the "point of no return" where (...) exhausted its yolk reserves and also irreversibly degraded critical tissues (...) energetic purposes it feeds is not ingested.

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