Antarctic Notothenioid Fishes Do Not Display Metabolic Cold Adaptation in Hepatic Gluconeogenesis

Antarctic notothenioid fishes present specializations related to their chronically cold environment, such as high lipid content in tissues (predominantly triacylglycerols, TAG). When TAGs are mobilized, they yield fatty acids and glycerol. Fatty acids are the primary fuel of oxidative muscle tissues. Gluconeogenesis from glycerol has not been studied in Antarctic fishes despite the importance of glycerol as a breakdown product of TAGs. To assess the possible importance of glycerol as a substrate for gluconeogenesis and to determine whether this pathway and Krebs cycle are metabolically cold adapted, key hepatic enzyme activities were measured in Antarctic notothenioid fishes (Notothenia coriiceps, Gobionotothen gibberifrons and Chionodraco rastrospinosus) and Subantarctic notothenioid fishes (Dissostichus eleginoides, Patagonotothen ramsayi and Eleginops maclovinus) . Citrate synthase, fructose 1,6-biphosphatase, glycerol kinase, and phosphoenolpyruvate carboxykinase enzyme activities were measured at lo, 60, 1 l o , and 2 10 C. Levels of specific metabolites in liver (glycerol, glucose and glycogen) and in serum (glycerol and glucose) were measured. My results indicate that gluconeogenesis and aerobic metabolism are not metabolically cold adapted in livers of Antarctic fishes. Levels of glycerol in plasma and liver were generally similar for all fishes studied, but surprisingly lower than the values reported for other teleost. Maximal activities for all enzymes assayed in livers of notothenioids fishes with Antarctic and Subantarctic distribution were similar when measured at the same temperature (loC). In addition, energies of activation for all the enzymes, calculated from the slope of Arrhenius plot, were similar between both groups of fishes. Lack of metabolic cold adaptation in hepatic gluconeogenesis may indicate that this pathway is of low physiological importance in both Antarctic and Subantarctic notothenioids or, more likely, that these two groups are so closely related that insufficient time has elapsed for evolutionary divergence in this tr

Dietary supplementation of heat-treated Gracilaria and Ulva seaweeds enhanced acute hypoxia tolerance in gilthead sea bream (Sparus aurata)

Intensive aquaculture practices involve rearing fish at high densities. In these conditions, fish may be exposed to suboptimal dissolved O2 levels with an increased formation of reactive O2 species (ROS) in tissues. Seaweeds (SW) contain biologically active substances with efficient antioxidant capacities. This study evaluated the effects of dietary supplementation of heat-treated SW (5% Gracilaria vermiculophylla or 5% Ulva lactuca) on stress bioindicators in sea bream subjected to a hypoxic challenge. 168 fish (104.5 g average weight) were distributed in 24 tanks, in which eight tanks were fed one of three experimental diets for 34 days: (i) a control diet without SW supplementation, (ii) a control diet supplemented with Ulva, or (iii) a control diet with Gracilaria. Thereafter, fish from 12 tanks (n=4 tanks/dietary treatment) were subjected to 24 h hypoxia (1.3 mg O2 l-1) and subsequent recovery normoxia (8.6 mg O2 l-1). Hypoxic fish showed an increase in hematocrit values regardless of dietary treatment. Dietary modulation of the O2-carrying capacity was conspicuous during recovery, as fish fed SW supplemented diets displayed significantly higher haemoglobin concentration than fish fed the control diet. After the challenge, survival rates in both groups of fish fed SW were higher, which was consistent with a decrease in hepatic lipid peroxidation in these groups. Furthermore, the hepatic antioxidant enzyme activities were modulated differently by changes in environmental O2 condition, particularly in sea bream fed the Gracilaria diet. After being subjected to hypoxia, the gene expression of antioxidant enzymes and molecular chaperones in liver and heart were down regulated in sea bream fed SW diets. This study suggests that the antioxidant properties of heat-treated SW may have a protective role against oxidative stress. The nature of these compounds and possible mechanisms implied are currently being investigated.Fil: Magnoni, Leonardo Julián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina. Universidad de Porto; PortugalFil: Martos Sitcha, Juan Antonio. Consejo Superior de Investigaciones Científicas; EspañaFil: Queiroz, Augusto. Universidad de Porto; PortugalFil: Calduch Giner, Josep Alvar. Consejo Superior de Investigaciones Científicas; EspañaFil: Magalhaes Gonçalves, Jose Fernando. Universidad de Porto; PortugalFil: Rocha, Cristina M.R.. Universidad de Porto; PortugalFil: Abreu, Helena T.. ALGAplus; PortugalFil: Schrama, Johan W.. Wageningen University; Países BajosFil: Ozorio, Rodrigo O.A.. Universidad de Porto; PortugalFil: Perez Sanchez, Jaume. Consejo Superior de Investigaciones Científicas; Españ

Deep RNA sequencing of the skeletal muscle transcriptome in swimming fish

Deep RNA sequencing (RNA-seq) was performed to provide an in-depth view of the transcriptome of red and white skeletal muscle of exercised and non-exercised rainbow trout (Oncorhynchus mykiss) with the specific objective to identify expressed genes and quantify the transcriptomic effects of swimming-induced exercise. Pubertal autumn-spawning seawater-raised female rainbow trout were rested (n = 10) or swum (n = 10) for 1176 km at 0.75 body-lengths per second in a 6,000-L swim-flume under reproductive conditions for 40 days. Red and white muscle RNA of exercised and non-exercised fish (4 lanes) was sequenced and resulted in 15-17 million reads per lane that, after de novo assembly, yielded 149,159 red and 118,572 white muscle contigs. Most contigs were annotated using an iterative homology search strategy against salmonid ESTs, the zebrafish Danio rerio genome and general Metazoan genes. When selecting for large contigs (>500 nucleotides), a number of novel rainbow trout gene sequences were identified in this study: 1,085 and 1,228 novel gene sequences for red and white muscle, respectively, which included a number of important molecules for skeletal muscle function. Transcriptomic analysis revealed that sustained swimming increased transcriptional activity in skeletal muscle and specifically an up-regulation of genes involved in muscle growth and developmental processes in white muscle. The unique collection of transcripts will contribute to our understanding of red and white muscle physiology, specifically during the long-term reproductive migration of salmonids

Deep RNA Sequencing of the Skeletal Muscle Transcriptome in Swimming Fish

Deep RNA sequencing (RNA-seq) was performed to provide an in-depth view of the transcriptome of red and white skeletal muscle of exercised and non-exercised rainbow trout (Oncorhynchus mykiss) with the specific objective to identify expressed genes and quantify the transcriptomic effects of swimming-induced exercise. Pubertal autumn-spawning seawater-raised female rainbow trout were rested (n = 10) or swum (n = 10) for 1176 km at 0.75 body-lengths per second in a 6,000-L swimflume under reproductive conditions for 40 days. Red and white muscle RNA of exercised and non-exercised fish (4 lanes) was sequenced and resulted in 15–17 million reads per lane that, after de novo assembly, yielded 149,159 red and 118,572 white muscle contigs. Most contigs were annotated using an iterative homology search strategy against salmonid ESTs, the zebrafish Danio rerio genome and general Metazoan genes. When selecting for large contigs (.500 nucleotides), a number of novel rainbow trout gene sequences were identified in this study: 1,085 and 1,228 novel gene sequences for red and white muscle, respectively, which included a number of important molecules for skeletal muscle function. Transcriptomic analysis revealed that sustained swimming increased transcriptional activity in skeletal muscle and specifically an upregulation of genes involved in muscle growth and developmental processes in white muscle. The unique collection of transcripts will contribute to our understanding of red and white muscle physiology, specifically during the long-term reproductive migration of salmonids.Fil: Palstra, Arjan P.. Universidad de Barcelona. Facultad de Biología; España;Fil: Beltran, Sergi. Universitat de Barcelona. Centres Cientifics i Tecnològics. Unitat de Bioinformàtica; España;Fil: Burgerhout, Erik. Leiden University. Institute of Biology. Molecular Cell Biology; Países Bajos; ZF-screens; Países Bajos;Fil: Brittijn, Sebastiaan A.. Leiden University. Institute of Biology. Molecular Cell Biology; Países Bajos; ZF-screens; Países Bajos;Fil: Magnoni, Leonardo Julián. Universidad de Barcelona. Facultad de Biología; España; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús. Instituto de Investigaciones Biotecnológicas (sede Chascomús); Argentina;Fil: Henkel, Christiaan V.. ZF-screens; Países Bajos;Fil: Jansen, Hans J.. ZF-screens; Países Bajos;Fil: Van Den Thillart, Guido E. E. J. M.. Leiden University. Institute of Biology. Molecular Cell Biology; Países Bajos; ZF-screens; Países Bajos;Fil: Spaink, Herman P.. Leiden University. Institute of Biology. Molecular Cell Biology; Países Bajos; ZF-screens; Países Bajos;Fil: Planas, Josep V.. Universidad de Barcelona. Facultad de Biologia; España

Elemental composition and bioaccessibility of farmed oysters (Crassostrea gigas) fed different ratios of dietary seaweed and microalgae during broodstock conditioning

Free PMC article: https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/31428337/[Correction added on 8 July 2019, after first online publication: New affiliation was added for Jorge Machado, José Fernando Gonçalves, and Paulo Vaz‐Pires.]The Pacific oyster (Crassostrea gigas) culture has been expanding, thereby leading to a greater importance of hatcheries. Broodstock conditioning is very important in the hatchery process, in which diet composition may have a strong influence on the offspring production and quality. Therefore, the current study evaluated elemental composition and bioaccessibility of oysters fed different ratios of dietary seaweed (SW) and microalgae. The dietary conditioning consisted of direct replacement of microalgae by SW at four substitution levels (0%, 25%, 50%, and 100% diet). It was observed that oysters fed 100% SW had the highest levels of Be, Cu, Zn, Sr, and Cd. The most important trend was a concentration decline of most elements with progressively lower levels of SW substitution for microalgae in the feeds. No Cd or Pb hazard (contents below 1.0 mg/kg for Cd and 1.5 mg/kg for Pb) was found in oyster meat. Regarding elemental bioaccessibility, values were similar, near 100% in the cases of Cu, Br, and I. Only for Mn and Pb, bioaccessibility percentages deviated more from 100%. Indeed, the value for Pb was 50% ± 7% (initial group), and for Mn, all values were equal or lower than 29% ± 2% (final group of oysters fed microalgae). It was observed that Mn, Cd, and Pb bioaccessibility increased with a growing share of microalgal biomass in the feed. Therefore, this study showed that SW incorporation into the feed influences elemental composition and bioaccessibility of the oysters.The current study was supported by Project INNOVMAR— Innovation and Sustainability in the Management and Exploitation of Marine Resources (NORTE‐01‐0145‐FEDER‐000035) within the line “INSEAFOOD, Innovation and valorization of seafood products,” funded by the Northern Regional Operational Programme (NORTE2020) through the European Regional Development Fund (ERDF). Moreover, the study was funded by the project AQUAMAX (Ref. 16‐02‐01‐FMP‐0047). This work was also supported by the following Postdoctoral Grants: Ref.: SFRH/BPD/102689/2014 (“Fundação para a Ciência e a Tecnologia,” FCT) for the author Carlos Cardoso, Ref.: SFRH/BD/129795/2017 (“Fundação para a Ciência e a Tecnologia,” FCT) for the author Joana Matos, and DIVERSIAQUA (MAR2020) for the author Cláudia Afonso.info:eu-repo/semantics/publishedVersio

AMP-Activated Protein Kinase Plays an Important Evolutionary Conserved Role in the Regulation of Glucose Metabolism in Fish Skeletal Muscle Cells

AMPK, a master metabolic switch, mediates the observed increase of glucose uptake in locomotory muscle of mammals during exercise. AMPK is activated by changes in the intracellular AMP∶ATP ratio when ATP consumption is stimulated by contractile activity but also by AICAR and metformin, compounds that increase glucose transport in mammalian muscle cells. However, the possible role of AMPK in the regulation of glucose metabolism in skeletal muscle has not been investigated in other vertebrates, including fish. In this study, we investigated the effects of AMPK activators on glucose uptake, AMPK activity, cell surface levels of trout GLUT4 and expression of GLUT1 and GLUT4 as well as the expression of enzymes regulating glucose disposal and PGC1α in trout myotubes derived from a primary muscle cell culture. We show that AICAR and metformin significantly stimulated glucose uptake (1.6 and 1.3 fold, respectively) and that Compound C completely abrogated the stimulatory effects of the AMPK activators on glucose uptake. The combination of insulin and AMPK activators did not result in additive nor synergistic effects on glucose uptake. Moreover, exposure of trout myotubes to AICAR and metformin resulted in an increase in AMPK activity (3.8 and 3 fold, respectively). We also provide evidence suggesting that stimulation of glucose uptake by AMPK activators in trout myotubes may take place, at least in part, by increasing the cell surface and mRNA levels of trout GLUT4. Finally, AICAR increased the mRNA levels of genes involved in glucose disposal (hexokinase, 6-phosphofructokinase, pyruvate kinase and citrate synthase) and mitochondrial biogenesis (PGC-1α) and did not affect glycogen content or glycogen synthase mRNA levels in trout myotubes. Therefore, we provide evidence, for the first time in non-mammalian vertebrates, suggesting a potentially important role of AMPK in stimulating glucose uptake and utilization in the skeletal muscle of fish

Editorial: Physiological Adaptations to Swimming in Fish

Swimming is an integral part of the life history of many fish species as is intimately linked with their ability to express feeding and predator avoidance behaviors, habitat selection and environmental preferences, social and reproductive behaviors as well as migratory behaviors (Videler, 1993; Palstra and Planas, 2011). Therefore, swimming is an important determinant factor of fitness in a true Darwinian sense and, not surprisingly, swimming performance has been often used as a measure of physiological fitness in fish (Hammer, 2005). In the face of growing changes in the aquatic environment due to global warming and other anthropogenic influences (e.g., hydropower plants and pumping stations, pollution, destruction of essential habitats, etc.), swimming performance can become a relevant proxy for the level of fitness in our evaluation of organismal responses to environmental perturbations in wild fish populations. Changes in the locomotory capabilities of fish due to alterations in swimming performance can have important consequences at the population level in terms of individual dispersal and species abundance, reproductive success and genetic structure of the fish populations, as shown in other vertebrate groups (Hillman et al., 2014). Reduced activity levels due to swimming in captivity can also decrease their physiological fitness status or condition as it is known to occur in aquaculture, when fish cannot display their normal swimming behavior due to confinement under high densities or to insufficient water flows to induce swimming, leading to decreased fitness (both physical and reproductive), growth, survival and muscle quality, depending on the swimming characteristics of the species (Palstra and Planas, 2013). An extensive body of literature supports the notion that swimming, through the ensuing muscle contraction and activation of the cardiovascular system, affects the physiology of the fish through adaptive mechanisms that are recently beginning to be uncovered (Palstra and Planas, 2013; Rodnick and Planas, 2016). Further research efforts in this area should inform the scientific community and the public on the ability of wild fish populations to cope with environmental change and on the benefits of induced swimming for improved aquaculture production and fish welfare.Fil: Planas, Josep V.. Universidad de Barcelona; EspañaFil: Palstra, Arjan P.. University Of Agriculture Wageningen; Países BajosFil: Magnoni, Leonardo Magnoni. Centro Interdisciplinar de Investigacoes Marinhas e Medioambientales; Portugal. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Trabajo Práctico Nº 2: Transformaciones geométricas : Taller Vertical de Matemática Nº 2 - Enrich-Creus-Carnicero

Se proponen distintos problemas y tareas a resolver por parte de los alumnos.Facultad de Arquitectura y Urbanism

Trabajo Práctico Nº 2: Transformaciones geométricas : Taller Vertical de Matemática Nº 2 - Enrich-Creus-Carnicero

Se proponen distintos problemas y tareas a resolver por parte de los alumnos.Facultad de Arquitectura y Urbanism