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Guerreiro da Costa Guerreiro, Pedro Miguel

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Now showing 1 - 10 of 20
  • Genetic and molecular analysis of phosphorus homeostasis regulatory genes. A key nutrient for aquaculture sustainability
    Publication . Suarez-Bregua, P.; Torres-Nunez, E.; Prober, D.; Cerda-Reverter, J. M.; Guerreiro, Pedro M; Du, S. J.; Canestro, C.; Rotllant, J.
  • Social organization and endocrine profiles of Australoheros facetus, an exotic freshwater fish in southern Portugal
    Publication . Baduy, F.; Silva, FBV; Guerreiro, Pedro M; Canario, A.V.M.; L. Saraiva, João
    Australoheros facetus is a neotropical cichlid and an exotic species in the Guadiana and Odelouca basins (Southern Portugal). In this research, we aimed to characterize the main behavioural patterns and circulating hormones, 17 beta-estradiol (E-2) for females, and testosterone, 11-ketotestosterone (11KT) and cortisol for both sexes, during the formation of social groups, a crucial step in the life-history of A. facetus. A pair-breeding strategy with territorial behaviour and aggressive interactions was found, with a positive correlation between dominance and size for both sexes. There were no significant differences between non-territorial and territorial individuals in the baseline levels of hormones, but 11KT was higher in males when they became territorial, as E-2 for territorial females, while there was no clear pattern for testosterone. In contrast, cortisol was higher in non-territorial males and correlated negatively with social dominance. These results suggest that size is the main driver for social dominance and that formation of stable hierarchies result in higher circulating 11KT and lowers stress in territorial males. Related to A. facetus' behaviour, aggressiveness and biparental care may be an advantage during the invasion process of A. facetus, facilitating colonization of new habitats.
  • STC1 and PTHrP modify carbohydrate and lipid metabolism in liver of a teleost fish
    Publication . Palma, Pedro F. S.; Bock, Christian; Silva, Tomé S.; Guerreiro, Pedro; Power, Deborah; Pörtner, Hans-Otto; Canario, Adelino
    Stanniocalcin 1 (STC1) and parathyroid hormone-related protein (PTHrP) are calciotropic hormones in vertebrates. Here, a recently hypothesized metabolic role for these hormones is tested on European sea bass treated with: (i) teleost PTHrP(1-34), (ii) PTHrP(1-34) and anti-STC1 serum (pro-PTHrP groups), (iii) a PTHrP antagonist PTHrP(7-34) or (iv) PTHrP(7-34) and STC1 (pro-STC1 groups). Livers were analysed using untargeted metabolic profiling based on proton nuclear magnetic resonance (1H-NMR) spectroscopy. Concentrations of branched-chain amino acid (BCAA), alanine, glutamine and glutamate increased in pro-STC1 groups suggesting their mobilization from the muscle to the liver for degradation and gluconeogenesis from alanine and glutamine. In addition, only STC1 treatment decreased the concentrations of succinate, fumarate and acetate, indicating slowing of the citric acid cycle. In the pro-PTHrP groups the concentrations of glucose, erythritol and lactate decreased, indicative of gluconeogenesis from lactate. Taurine, trimethylamine, trimethylamine N-oxide and carnitine changed in opposite directions in the pro-STC1 versus the pro-PTHrP groups, suggesting opposite effects, with STC1 stimulating lipogenesis and PTHrP activating lipolysis/β-oxidation of fatty acids. These findings suggest a role for STC1 and PTHrP related to strategic energy mechanisms that involve the production of glucose and safeguard of liver glycogen reserves for stressful situations.
  • PRL and GH synthesis and release from the sea bream (Sparus auratus L.) pituitary gland in vitro in response to osmotic challenge
    Publication . Fuentes, J.; Brinca, Lilia; Guerreiro, P. M.; Power, Deborah
    The endocrine factors prolactin (PRL) and growth hormone (GH) are believed to have counteracting effects in the adaption of fish to changes in environmental salinity. In order to further investigate this interaction sea bream were challenged with full seawater (SW) or freshwater (FW) for 7 days and the response of pituitary glands cultured in vitro to an osmotic challenge (230, 275 and 320 mOsm/kg) was assessed. In vitro PRL secretion from pituitaries of SW-adapted fish was unaltered in response to an osmotic challenge, while GH secretion increased in the lowest osmolality (230 mOsm/kg). In contrast, both GH and PRL secretion by pituitaries from FW challenged fish was significantly increased (p < 0.01) over that of pituitaries from SW fish at the highest osmolality (320 mOsm/kg). After FW challenge pituitary PRL content and de novo synthesised and released PRL were significantly increased (p < 0.01), while total PRL secretion was not different from SW animals. GH pituitary content decreased in FW animals while total secretion and secretion of de novo synthesised protein were significantly increased (p < 0.01). In addition, after transfer of fish to FW expression of PRL and GH increased 3- and 2-fold, respectively. Despite the increase in PRL expression, no increase in total PRL secretion occurred and although in gills a 2-fold increase in the osmoregulatory marker, Na+/K+-ATPase activity was detected, profound haemodilution and a cumulative mortality of 40% occurred in sea bream placed in FW. Taken together the results suggest that the sea bream pituitary gland fails to respond appropriately to the osmotic challenge caused by low salinity and the physiological response evoked in vivo is not enough to allow this species to withstand and adapt to FW.
  • Conservation physiology of marine fishes: state of the art and prospects for policy
    Publication . McKenzie, David J.; Axelsson, Michael; Chabot, Denis; Claireaux, Guy; Cooke, Steven J.; Corner, Richard A.; De Boeck, Gudrun; Domenici, Paolo; Guerreiro, Pedro M; Hamer, Bojan; Jørgensen, Christian; Killen, Shaun S.; Lefevre, Sjannie; Marras, Stefano; Michaelidis, Basile; Nilsson, Göran E.; Peck, Myron A.; Perez-Ruzafa, Angel; Rijnsdorp, Adriaan D.; Shiels, Holly A.; Steffensen, John F.; Svendsen, Jon C.; Svendsen, Morten B. S.; Teal, Lorna R.; van der Meer, Jaap; Wang, Tobias; Wilson, Jonathan M.; Wilson, Rod W.; Metcalfe, Julian D.
    The state of the art of research on the environmental physiology of marine fishes is reviewed from the perspective of how it can contribute to conservation of biodiversity and fishery resources. A major constraint to application of physiological knowledge for conservation of marine fishes is the limited knowledge base; international collaboration is needed to study the environmental physiology of a wider range of species. Multifactorial field and laboratory studies on biomarkers hold promise to relate ecophysiology directly to habitat quality and population status. The 'Fry paradigm' could have broad applications for conservation physiology research if it provides a universal mechanism to link physiological function with ecological performance and population dynamics of fishes, through effects of abiotic conditions on aerobic metabolic scope. The available data indicate, however, that the paradigm is not universal, so further research is required on a wide diversity of species. Fish physiologists should interact closely with researchers developing ecological models, in order to investigate how integrating physiological information improves confidence in projecting effects of global change; for example, with mechanistic models that define habitat suitability based upon potential for aerobic scope or outputs of a dynamic energy budget. One major challenge to upscaling from physiology of individuals to the level of species and communities is incorporating intraspecific variation, which could be a crucial component of species' resilience to global change. Understanding what fishes do in the wild is also a challenge, but techniques of biotelemetry and biologging are providing novel information towards effective conservation. Overall, fish physiologists must strive to render research outputs more applicable to management and decision-making. There are various potential avenues for information flow, in the shorter term directly through biomarker studies and in the longer term by collaborating with modellers and fishery biologists.
  • Effects of different slipping methods on the mortality of sardine, Sardina pilchardus, after purse-seine capture off the Portuguese Southern coast (Algarve)
    Publication . Marçalo, Ana; Guerreiro, Pedro; Bentes, Luis; Rangel, Mafalda; Monteiro, Pedro; Oliveira, Frederico; Afonso, Carlos; Pousao-Ferreira, Pedro; Benoit, Hugues P.; Breen, Mike; Erzini, Karim; Gonçalves, Jorge Manuel Santos
    The effects of two different slipping methods on the survival, physical and physiological response of sardines, Sardina pilchardus, captured in a purse-seine fishery were investigated in southern Portugal. Sardines were collected and transferred into holding tanks onboard a commercial fishing vessel after being captured, crowded and deliberately released using two slipping procedures: standard and modified. The standard slipping procedure aggregated fish at high densities and made them "roll over" the floatline, while the modified procedure aggregated the fish at moderate densities and enabled them to escape through an opening created by adding weights to the floatline. Both slipping methods were compared with minimally harmed non-slipped sardines (sardines collected from the loose pocket of the purse seine). Survival rates were monitored in captivity over 28 days using three replicates for each treatment. The estimated survival of sardines was 43.6% for the non-slipped fish, 44.7% for the modified slipping and 11.7% for the standard slipping treatments. Scale loss indicated the level of physical impact experienced, with dead fish from the non-slipped and modified slipping technique showing significantly lower scale loss than those fish from the standard slipping treatment within the same period. Of the physiological indicators of stress measured, cortisol, glucose, lactate and osmolality attained peak values during slipping and up to the first hours after introduction to captivity. This work indicates that although delayed mortality after release may be substantial, appropriately modified slipping techniques significantly enhance survival of slipped sardines.
  • Taxonomic re-evaluation of the non-native cichlid in Portuguese drainages
    Publication . Carecho, João; Baduy, F.; Silva, FBV; Guerreiro, Pedro; Saraiva, João L.; Ribeiro, Filipe; Veríssimo, Ana
    A non-native cichlid fish firstly reported in Portugal in 1940 was originally identified as Cichlasoma facetum (Jenyns 1842) based on specimens reported from “Praia de Mira” (Vouga drainage, northwestern Portugal). Currently, the species is known only from three southern Portuguese river drainages, namely Sado, Arade and Guadiana, and no other record has been made from Praia de Mira or the Vouga drainage since the original record. The genus Cichlasoma has since suffered major taxonomic revisions: C. facetum has been considered a species-complex and proposed as the new genus Australoheros, including many species. Given the current taxonomic re-arrangement of the C. facetum species group, we performed a taxonomic re-evaluation of species identity of this non-native cichlid in Portuguese drainages using morphological and molecular analyses. Morphological data collected on specimens sampled in the Sado river drainages confirmed the identification as Australoheros facetus. Moreover, nucleotide sequences of the cytochrome b gene obtained from specimens from Sado, Arade and Guadiana showed the existence of a single haplotype across drainages, which was 100% identical to A. facetus specimens collected in native Argentinean waters (i.e. Uruguay River). The current non-native distribution range of the species in Portugal results from human-mediated introductions across the southern drainages.
  • Stanniocalcin 1 effects on the renal gluconeogenesis pathway in rat and fish
    Publication . Schein, Vanessa; Kucharski, Luiz C.; M Guerreiro, Pedro; Martins, Tiago Leal; Morgado, Isabel; Power, Deborah M.; Canario, Adelino V. M.; da Silva, Roselis S. M.
    The mammalian kidney contributes significantly to glucose homeostasis through gluconeogenesis. Considering that stanniocalcin 1 (STC1) regulates ATP production, is synthesized and acts in different cell types of the nephron, the present study hypothesized that STC1 may be implicated in the regulation of gluconeogenesis in the vertebrate kidney. Human STC1 strongly reduced gluconeogenesis from C-14-glutamine in rat renal medulla (MD) slices but not in renal cortex (CX), nor from C-14-lactic acid. Total PEPCK activity was markedly reduced by hSTC1 in MD but not in CX. Pck2 (mitochondrial PEPCK isoform) was down-regulated by hSTC1 in MD but not in CX. In fish (Dicentrarchus labrax) kidney slices, both STC1-A and -B isoforms decreased gluconeogenesis from C-14-acid lactic, while STC1-A increased gluconeogenesis from C-14-glutamine. Overall, our results demonstrate a role for STC1 in the control of glucose synthesis via renal gluconeogenesis in mammals and suggest that it may have a similar role in teleost fishes. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
  • Cold-induced growth arrest in gilthead sea bream Sparus aurata: metabolic reorganisation and recovery
    Publication . Sánchez-Nuño, S.; Eroldogan, O. T.; Sanahuja, I.; Özşahniğlu, I.; Blasco, J.; Fernández-Borràs, J.; Fontanillas, R.; Guerreiro, Pedro M; Ibarz, A.
    There are currently no standard diets or practices to counteract or ameliorate the growth arrest and extremely poor feed conversion rates (FCR) in gilthead sea bream Sparus aurata caused by low water temperatures. The present study analysed the effects of reducing dietary lipid content from 18 to 14 % during a temperature fluctuation period. Temperature was gradually reduced from 22 degrees to 14 degrees C over a period of 5 d, and maintained at this low temperature for a further 45 d before gradual recovery over 7 d to 22 degrees C under controlled conditions, avoiding other stressors often present in cage culture conditions. Decreasing dietary lipid content at an elevated temperature (22 degrees C) did not significantly affect the standard growth rate or FCRs of the sea bream, indicating a possibility to reduce the dietary energy during the months before winter. Although cold-induced growth arrest and metabolic depression were unavoidable, a well-formulated, low-lipid diet adequately met the low energy demands at low temperatures. Analysis of plasma metabolites and liver enzyme activities demonstrated a reorganisation of liver metabolism, mainly in fish on a low-lipid diet. Recovery from low temperatures was delayed, with a higher dietary lipid content required for optimal liver condition, and mineral supplementation to maintain osmoregulation and bone formation. Our results provide useful information for fish producers and researchers, suggesting that dietary lipid contents should be reduced to allow fish to better cope with low temperatures, and that improved diets with higher lipid content are required for recovery from low temperatures.
  • Piscine PTHrP regulation of calcium and phosphate transport in winter flounder renal proximal tubule primary cultures
    Publication . Guerreiro, P. M.; Canario, Adelino V. M.; Power, Deborah; Renfro, J. Larry
    Multiple factors control calcium (Ca2 ) and inorganic phosphate (Pi) transport in the fish nephron, and the recently discovered members of the piscine parathyroid hormone-like protein family are likely participants in such regulatory mechanisms. The effects of an NH2-terminal peptide (amino acids 1–34) of Takifugu rubripes parathyroid hormone-related protein, (1–34)PTHrP, on Ca2 and Pi transport were investigated in winter flounder (Pseudopleuronectes americanus) proximal tubule cells in primary culture (fPTCs). RT-PCR performed on RNA extracted from fPTCs and from intact kidney tissue indicated that expression of PTHrP and types 1 and 3 PTH/PTHrP receptors occurred both in vivo and in vitro and that circulating levels of PTHrP measured by specific radioimmunoassay averaged 2.5 0.13 ng/ml. fPTC monolayers were mounted in Ussing chambers, and under neutral electrochemical conditions, addition of 10 nM (1–34)PTHrP to the basolateral side induced a slight increase in Ca2 transport rate from luminal to peritubular side, significantly stimulating net Ca2 reabsorption. (1–34)PTHrP also significantly increased the Pi secretory flux, and slightly reduced Pi reabsorption, evoking a significant increase in Pi net secretion. This stimulatory effect was partially inhibited by bisindolylmaleimide, an inhibitor of protein kinase C. Incubation of ex vivo flounder renal tubules with (1–34)PTHrP resulted in apparent reduction of Na -Pi cotransporter type II (NaPi-II) protein in tubule membranes. PTHrP seems therefore to participate in the modulation of Ca2 and Pi homeostasis by fish kidney.