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AAPS PharmSciTech     Hybrid Journal   (Followers: 6)
Acetic Acid Bacteria     Open Access   (Followers: 1)
ACS Central Science     Hybrid Journal   (Followers: 4)
ACS Chemical Biology     Full-text available via subscription   (Followers: 165)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 15)
Acta Crystallographica Section D : Biological Crystallography     Hybrid Journal   (Followers: 10)
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Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 7)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 13)
African Journal of Biochemistry Research     Open Access   (Followers: 1)
African Journal of Chemical Education     Open Access   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
American Journal of Biochemistry     Open Access   (Followers: 7)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 61)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 13)
American Journal of Polymer Science     Open Access   (Followers: 22)
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Angiogenesis     Hybrid Journal   (Followers: 2)
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Annual Review of Biochemistry     Full-text available via subscription   (Followers: 51)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 9)
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Asian Journal of Biochemistry     Open Access   (Followers: 1)
Avicenna Journal of Medical Biochemistry     Open Access  
Bangladesh Journal of Medical Biochemistry     Open Access   (Followers: 2)
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Biochemistry (Moscow)     Hybrid Journal   (Followers: 4)
Biochemistry (Moscow) Supplement Series A: Membrane and Cell Biology     Hybrid Journal   (Followers: 3)
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Biochemistry and Biophysics Reports     Open Access  
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Biochemistry and Molecular Biology Education     Hybrid Journal   (Followers: 5)
Biochemistry and Molecular Biology of Fishes     Full-text available via subscription   (Followers: 1)
Biochemistry Research International     Open Access   (Followers: 5)
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids     Hybrid Journal   (Followers: 9)
Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease     Hybrid Journal   (Followers: 16)
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Bitácora Digital     Open Access  
BMC Biochemistry     Open Access   (Followers: 14)
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca : Food Science and Technology     Open Access  
Carbohydrate Polymers     Hybrid Journal   (Followers: 7)
Cell Biochemistry and Biophysics     Hybrid Journal   (Followers: 5)
Cell Biochemistry and Function     Hybrid Journal   (Followers: 4)
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ChemBioChem     Hybrid Journal   (Followers: 5)
Chemical and Biological Technologies for Agriculture     Open Access  
Chemical Biology & Drug Design     Hybrid Journal   (Followers: 21)
Chemical Engineering Journal     Hybrid Journal   (Followers: 27)
Chemical Senses     Hybrid Journal   (Followers: 1)
Chemical Speciation and Bioavailability     Open Access   (Followers: 1)
Chemico-Biological Interactions     Hybrid Journal   (Followers: 3)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 5)
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Clinica Chimica Acta     Hybrid Journal   (Followers: 35)
Clinical Biochemist Reviews     Full-text available via subscription   (Followers: 1)
Clinical Biochemistry     Hybrid Journal   (Followers: 19)
Clinical Chemistry     Full-text available via subscription   (Followers: 68)
Clinical Chemistry and Laboratory Medicine     Hybrid Journal   (Followers: 63)
Clinical Lipidology     Full-text available via subscription  
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology     Hybrid Journal   (Followers: 5)
Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 2)
Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology     Hybrid Journal   (Followers: 7)
Comparative Biochemistry and Physiology Part D: Genomics and Proteomics     Hybrid Journal   (Followers: 3)
Comprehensive Biochemistry     Full-text available via subscription   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 9)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 4)
Current Chemical Biology     Hybrid Journal   (Followers: 2)
Current Medicinal Chemistry     Hybrid Journal   (Followers: 14)
Current Opinion in Chemical Biology     Hybrid Journal   (Followers: 21)
Current Opinion in Lipidology     Hybrid Journal   (Followers: 6)
DNA Barcodes     Open Access  
Doklady Biochemistry and Biophysics     Hybrid Journal   (Followers: 1)
Doklady Chemistry     Hybrid Journal  
Egyptian Journal of Biochemistry and Molecular Biology     Full-text available via subscription  
FABICIB     Open Access  
FEBS Letters     Hybrid Journal   (Followers: 58)
FEBS Open Bio     Open Access   (Followers: 3)
Fish Physiology and Biochemistry     Hybrid Journal   (Followers: 4)
Food & Function     Full-text available via subscription   (Followers: 5)
Foundations of Modern Biochemistry     Full-text available via subscription  
Free Radicals and Antioxidants     Full-text available via subscription   (Followers: 3)
Frontiers in Molecular Biosciences     Open Access   (Followers: 2)
Frontiers in Natural Product Chemistry     Hybrid Journal  
Global Biogeochemical Cycles     Full-text available via subscription   (Followers: 11)
Green Chemistry     Full-text available via subscription   (Followers: 8)
Histochemistry and Cell Biology     Hybrid Journal   (Followers: 4)
Indian Journal of Biochemistry and Biophysics (IJBB)     Open Access   (Followers: 3)
Indian Journal of Clinical Biochemistry     Hybrid Journal   (Followers: 1)
Indonesian Biomedical Journal     Open Access  
Insect Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 3)
International Journal of Biochemistry & Cell Biology     Hybrid Journal   (Followers: 7)
International Journal of Biochemistry and Biophysics     Open Access   (Followers: 1)
International Journal of Biological Chemistry     Open Access   (Followers: 4)
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 5)
International Journal of Food Contamination     Open Access  
International Journal of Plant Physiology and Biochemistry     Open Access  
International Journal of Plant Research     Open Access   (Followers: 3)
International Journal of Secondary Metabolite     Open Access   (Followers: 1)
Invertebrate Immunity     Open Access   (Followers: 1)
JBIC Journal of Biological Inorganic Chemistry     Hybrid Journal   (Followers: 4)
Journal of Microbial & Biochemical Technology     Open Access   (Followers: 1)
Journal of Applied Biology & Biotechnology     Open Access   (Followers: 1)
Journal of Bioactive and Compatible Polymers     Hybrid Journal   (Followers: 2)
Journal of Biochemistry     Hybrid Journal   (Followers: 42)
Journal of Biological Chemistry     Full-text available via subscription   (Followers: 166)
Journal of Biomaterials Science, Polymer Edition     Hybrid Journal   (Followers: 9)
Journal of Carbohydrate Chemistry     Hybrid Journal   (Followers: 7)
Journal of Cellular Biochemistry     Hybrid Journal   (Followers: 5)
Journal of Chemical Biology     Hybrid Journal   (Followers: 1)
Journal of Chemical Neuroanatomy     Hybrid Journal  
Journal of Clinical Lipidology     Hybrid Journal   (Followers: 1)
Journal of Comparative Physiology B : Biochemical, Systemic, and Environmental Physiology     Hybrid Journal   (Followers: 4)
Journal of Drug Discovery and Therapeutics     Open Access   (Followers: 1)
Journal of Enzyme Inhibition and Medicinal Chemistry     Hybrid Journal   (Followers: 4)
Journal of Evolutionary Biochemistry and Physiology     Hybrid Journal  
Journal of Food and Drug Analysis     Open Access  
Journal of Forensic Toxicology and Pharmacology     Hybrid Journal   (Followers: 3)
Journal of Inborn Errors of Metabolism and Screening     Open Access  
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 3)
Journal of Investigational Biochemistry     Open Access   (Followers: 2)
Journal of Medical and Biomedical Sciences     Open Access  
Journal of Medical Biochemistry     Open Access   (Followers: 4)
Journal of Medicine and Biomedical Research     Open Access   (Followers: 1)
Journal of Molecular Biochemistry     Open Access   (Followers: 3)
Journal of Molecular Diagnostics     Hybrid Journal   (Followers: 6)
Journal of Neurochemistry     Hybrid Journal   (Followers: 3)
Journal of Nutritional Biochemistry     Hybrid Journal   (Followers: 7)
Journal of Pediatric Biochemistry     Hybrid Journal   (Followers: 1)
Journal of Peptide Science     Hybrid Journal   (Followers: 24)
Journal of Photochemistry and Photobiology B: Biology     Hybrid Journal   (Followers: 3)
Journal of Physiobiochemical Metabolism     Hybrid Journal   (Followers: 1)
Journal of Physiology and Biochemistry     Hybrid Journal   (Followers: 3)
Journal of Plant Biochemistry and Biotechnology     Hybrid Journal   (Followers: 5)
Journal of Steroid Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 2)
Journal of Virology & Antiviral Research     Hybrid Journal   (Followers: 3)
Journal of Wood Chemistry and Technology     Hybrid Journal   (Followers: 7)
La Rivista Italiana della Medicina di Laboratorio - Italian Journal of Laboratory Medicine     Hybrid Journal  
Lab on a Chip     Full-text available via subscription   (Followers: 34)
Marine Chemistry     Hybrid Journal   (Followers: 6)
Methods in Enzymology     Full-text available via subscription   (Followers: 11)
Molecular and Biochemical Parasitology     Hybrid Journal   (Followers: 2)
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Molecular Aspects of Medicine     Hybrid Journal   (Followers: 4)
Molecular Informatics     Hybrid Journal   (Followers: 5)
Molecular inhibitors in targeted therapy     Open Access  
Moscow University Chemistry Bulletin     Hybrid Journal   (Followers: 1)
Mycology : An International Journal on Fungal Biology     Hybrid Journal   (Followers: 4)
Natural Products and Bioprospecting     Open Access   (Followers: 3)
Nature Chemical Biology     Full-text available via subscription   (Followers: 65)
Nature Communications     Open Access   (Followers: 103)
Neurosignals     Open Access   (Followers: 2)
Novelty in Biomedicine     Open Access  
Ocean Acidification     Open Access   (Followers: 2)
Organic & Biomolecular Chemistry     Full-text available via subscription   (Followers: 83)
Peptidomics     Open Access  
Pesticide Biochemistry and Physiology     Hybrid Journal   (Followers: 4)
Pflugers Archiv European Journal of Physiology     Hybrid Journal   (Followers: 3)
Pharmaceutical Bioprocessing     Full-text available via subscription   (Followers: 1)
Pharmacognosy Magazine     Open Access   (Followers: 2)

        1 2     

Journal Cover Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
  [SJR: 0.939]   [H-I: 84]   [5 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1095-6433
   Published by Elsevier Homepage  [3039 journals]
  • Molecular characterization of a cDNA encoding Na+/K+/2Cl− cotransporter
           in the gill of mud crab (Scylla paramamosain) during the molt cycle:
           Implication of its function in osmoregulation
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Bin-peng Xu, Dan-dan Tu, Mao-cang Yan, Miao-an Shu, Qing-jun Shao
      Although iono-regulatory processes are critical for survival of crustaceans during the molt cycle, the mechanisms involved are still not clear. The Na+/K+/2Cl− cotransporter (NKCC), a SLC12A family protein that transports Na+, K+ and 2Cl− into cells, is essential for cell ionic and osmotic regulation. To better understand the role of NKCC in the molt osmoregulation, we cloned and characterized a NKCC gene from the mud crab, Scylla paramamosain (designated as SpNKCC). The predicted SpNKCC protein is well conserved, and phylogenetic analysis revealed that this protein was clustered with crustacean NKCC. Expression of SpNKCC was detected in all the tissues examined but was highest in the posterior gills. Transmission electron microscopy revealed that posterior gills had a thick type of epithelium for ion regulation while the anterior gills possessed a thin phenotype related to gas exchange. During the molting cycle, hemolymph osmolality and ion concentrations (Na+ and Cl−) increased significantly over the postmolt period, remained stable in the intermolt and premolt stages and then decreased at ecdysis. Meanwhile, the expression of SpNKCC mRNA was significantly elevated (26.7 to 338.8-fold) at the ion re-establishing stages (postmolt) as compared with baseline molt level. This pattern was consistent with the coordinated regulation of Na+/K+-ATPase α-subunit (NKA α), carbonic anhydrase cytoplasmic (CAc) isoform and Na+/H+ exchanger (NHE) genes in the posterior gills. These data suggest that SpNKCC may be important in mediating branchial ion uptake during the molt cycle, especially at the postmolt stages.

      PubDate: 2016-09-21T01:27:29Z
  • Nonphotic entrainment in fish
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Jose F. López-Olmeda
      Organisms that live on the Earth are subjected to environmental variables that display cyclic variations, such as light, temperature and tides. Since these cyclic changes in the environment are constant and predictable, they have affected biological evolution through selecting the occurrence of biological rhythms in the physiology of all living organisms, from prokaryotes to mammals. Biological clocks confer organisms an adaptive advantage as they can synchronize their behavioral and physiological processes to occur at a given moment of time when effectiveness and success would be greater and/or the cost and risk for organisms would be lower. Among environmental synchronizers, light has been mostly widely studied to date. However, other environmental signals play an important role in biological rhythms, especially in aquatic animals like fish. This review focuses on current knowledge about the role of nonphotic synchronizers (temperature, food and tidal cycles) on biological rhythms in fish, and on the entrainment of the fish circadian system to these synchronizers.

      PubDate: 2016-09-21T01:27:29Z
  • Salinity responsive aquaporins in the anal papillae of the larval
           mosquito, Aedes aegypti
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Hina Akhter, Lidiya Misyura, Phuong Bui, Andrew Donini
      The larvae of the mosquito, Aedes aegypti normally inhabit freshwater (FW) where they face dilution of body fluids by osmotic influx of water. In response, the physiological actions of the anal papillae result in ion uptake while the Malpighian tubules and rectum work in concert to excrete excess water. In an apparent paradox, the anal papillae express aquaporins (AQPs) and are sites of water permeability which, if AQPs are expressed by the epithelium, apparently exaggerates the influx of water from their dilute environment. Recently, naturally breeding populations of A. aegypti were found in brackish water (BW), an environment which limits the osmotic gradient. Given that salinization of FW is an emerging environmental issue and that these larvae would presumably need to adjust to these changing conditions, this study investigates the expression of AQPs in the anal papillae and their response to rearing in hypo-osmotic and near isosmotic conditions. Transcripts of all six Aedes AQP homologs were detectable in the anal papillae and the transcript abundance of three AQP homologs in the papillae was different between rearing conditions. Using custom made antibodies, expression of two of these AQP homologs (AQP4 and AQP5) was localized to the syncytial epithelium of the anal papillae. Furthermore, the changes in transcript abundance of these two AQPs between the rearing conditions, were manifested at the protein level. Results suggest that AQP4 and AQP5 play an important physiological role in larval responses to changes in environmental salinity.

      PubDate: 2016-09-21T01:27:29Z
  • Involvement of cholecystokinin (CCK) in the daily pattern of
           gastrointestinal regulation of Senegalese sole (Solea senegalensis) larvae
           reared under different feeding regimes
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Carmen Navarro-Guillén, Ivar Rønnestad, Ann-Elise Olderbakk Jordal, Francisco Javier Moyano, Manuel Yúfera
      Cholecystokinin (CCK) is an important regulator of pancreatic enzyme secretion in adult mammals and teleosteans. Although some studies have focused on the interaction between CCK and trypsin in marine fish larvae, little is known about the circadian patterns of the regulatory mechanism involving these two digestive components. In this study, we took advantage of the characteristic change from a diurnal to a nocturnal feeding habit that occurs in Senegalese sole (Solea senegalensis) post-larvae, to conduct an experiment where larvae and postlarvae were submitted to three different feeding regimes from mouth opening: continuous feeding, diurnal feeding and nocturnal feeding. The aim was to establish different daily feeding scenarios to uncover the operating mechanisms of CCK and tryptic enzyme activity over the 24-hourcycle to better understand the regulation of digestion in developing fish larvae. Results show a prevalence of simultaneous and opposing trends of CCK level and tryptic activity as a function of the postprandial time. This finding supports the existence of a regulatory loop between these two digestive components in pre- and post-metamorphic Senegal sole larvae. In addition, CCK level was also modulated by the gut content, tending to be lower when the gut is full and higher when is being emptied. Furthermore, larvae were able to synchronize digestive functions to very different feeding regimes, although it seems to be important having a diurnal feeding phase during pre-metamorphic stages for a proper development.

      PubDate: 2016-09-21T01:27:29Z
  • Molecular drivers of mitochondrial membrane proliferation in response to
           cold acclimation in threespine stickleback
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Kelly Keenan, Megan Hoffman, Kristin Dullen, Kristin M. O'Brien
      Little is known about how the synthesis of mitochondrial phospholipids is integrated into mitochondrial biogenesis in fish or mammals. Glycerol-3-phosphate acyltransferase (GPAT; EC catalyzes the addition of fatty acyl CoA to the sn-1 position of glycerol-3-phosphate, in what is considered the rate-limiting step in phospholipid biosynthesis. Previous studies have shown that mitochondrial volume density increases in oxidative skeletal muscle but not liver of Gasterosteus aculeatus (threespine stickleback) in response to cold acclimation. We hypothesized that maximal activity of GPAT would increase in oxidative skeletal muscle but not liver during cold acclimation, coinciding with mitochondrial biogenesis. GPAT activity was measured in liver and oxidative skeletal (pectoral adductor) muscle of threespine stickleback acclimated to 8°C or 20°C. In addition, mRNA levels of enzymes involved in phospholipid synthesis, including cytidine diphosphodiacylglycerol synthase-1 (CDS1), CDS2, GPAT1, GPAT2 and 1-acylglycerol 3-phosphate acyltransferase-2 (AGPAT2), were quantified in liver and pectoral muscle of stickleback harvested during cold acclimation. GPAT activity and transcript levels of AGPAT2 increased in response to cold acclimation in pectoral muscle but not liver. Transcript levels of GPAT1 increased in liver but not pectoral muscle. Overall our results suggest that the activity of GPAT, and possibly AGPAT as well, increase during cold acclimation and may contribute to mitochondrial phospholipid biosynthesis required for mitochondrial biogenesis.

      PubDate: 2016-09-15T15:55:04Z
  • Vibrational sensitivity of the subgenual organ complex in female
           Sipyloidea sipylus stick insects in different experimental paradigms of
           stimulus direction, leg attachment, and ablation of a connective tibial
           sense organ
    • Abstract: Publication date: Available online 7 September 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Johannes Strauß, Reinhard Lakes-Harlan
      We document the sensitivity to sinusoidal vibrations for chordotonal organs in the stick insect tibia (Sipyloidea sipylus). In the tibia, the scolopidial subgenual organ (~40 scolopidial sensilla), distal organ (~20 scolopidial sensilla), and distal tibial chordotonal organ (~7 scolopidial sensilla) are present. We study the sensitivity of tibial sensory organs in all leg pairs to vibration stimuli as sensory thresholds by recording summed action potentials from Nervus cruris in the femur. The tibia was stimulated with a minishaker delivering vibrational stimuli. Because different experimental procedures may affect the vibration sensitivity, we here analysed possible effects of different experimental conditions: (1) the stimulus direction delivered in either horizontal or vertical direction to the leg; (2) recording responses only from the subgenual organ complex after ablation of the distal tibial chordotonal organ, and (3) the attachment of the leg to the minishaker by plastilin, beeswax-colophony, or freely standing legs. The tibial scolopidial organs give summed responses to vibration stimuli with highest sensitivity between 500 and 1000Hz for all leg pairs. In the different experimental series, we find that (1) thresholds were influenced by stimulation direction with lower thresholds in response to vertical vibrations, (2) ablating the distal tibial chordotonal organ by cutting the distal-most tibia did not change the summed sensory thresholds significantly, and (3) the attachment material between legs and the minishaker (plastilin or beeswax-colophony mixture) did not significant influence the sensory thresholds against free-standing tarsi. The distal tibial chordotonal organ is a connective chordotonal organ attached to a tendon and is likely a proprioceptive organ. These results emphasise that vibrational thresholds are mainly direction-sensitive. Thus, the direction of stimulus delivery during electrophysiological recordings is relevant for comparisons of vibratory sensory thresholds.

      PubDate: 2016-09-10T15:33:25Z
  • Editorial Board
    • Abstract: Publication date: October 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 200

      PubDate: 2016-09-10T15:33:25Z
  • Fe, oxidative and nitrosative metabolism in the Antarctic limpet Nacella
    • Abstract: Publication date: October 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 200
      Author(s): Paula Mariela González, Susana Puntarulo
      The hypothesis of this work was that oxidative and nitrosative metabolism in the digestive gland (DG) of two limpet populations (intertidal and subtidal) of the Antarctic species Nacella concinna show different behavior when they were exposed to either intermittent (intertidal) or constant (subtidal) natural Fe. Total Fe content and labile Fe pool were higher in the DG of the subtidal compared to the intertidal population. However, no significant differences between populations were seen on the Fe atoms content of the isolated ferritin. Ascorbyl radical content was 2.0±0.4 and 6.5±0.8pmol/mg FW in the DG of the intertidal and subtidal animals, respectively. Lipid damage, assessed as content of thiobarbituric reactive substances, was different between the tissues of intertidal and subtidal samples, 491±102 and 1242±367pmol/mg FW, respectively. Catalase and superoxide dismutase activities showed no differences between the limpets. Nitric oxide (NO) content was 25±3 and 22±2pmol/mg FW in DG from intertidal and subtidal animals, respectively. NO synthase-like (NOS-like) activity was evaluated supplementing the samples with the enzyme co-factors, and the inhibitory effect of Nω-nitro-L-arginine methyl ester hydrochloride was tested. NO generation rate was 3.4±0.3 and 4.7±0.6pmol/minmg FW in DG from the intertidal and subtidal population, respectively. These results showed that the oxidative condition of the limpet population constantly covered by the Fe enriched water is more affected than the intertidal population. However, the nitrosative metabolism seems to be independent of the environmental high Fe content since similar NO steady state concentration and NOS-like activity were measured in both populations.

      PubDate: 2016-09-10T15:33:25Z
  • Assessment of pollution of the Boca de Camichin Estuary in Nayarit
           (Mexico) and its influence on oxidative stress in Crassostrea corteziensis
    • Abstract: Publication date: October 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 200
      Author(s): G.A. Toledo-Ibarra, K.J.G. Díaz Resendiz, G.H. Ventura-Ramón, C.A. Romero-Bañuelos, I.M. Medina-Díaz, A.E. Rojas-García, A. Vega-López, M.I. Girón-Pérez
      Boca de Camichin Estuary is one of the main producers of Crassostrea corteziensis oysters in Mexico, but the presence of pollutants can affect oyster production. Molluscs produce reactive oxygen species (ROS) in response to changes in the environment and pollution. These ROS induce oxidative damage in biomolecules. The main objective of this study was to evaluate pollution in the estuary and the subsequent oxidative stress in C. corteziensis oysters during the 2010 production cycle. For this aim, we performed monthly samplings in the oyster farms from January to May. We took water samples to quantify polycyclic aromatic hydrocarbon (PAH) and metal content; also, we evaluated oxidative damage (lipoperoxidation, lipidic hydroperoxides, protein oxidation) and enzyme activity (CAT, SOD, GPx, GST and AChE) in oyster gills. The results show the presence of Cu, Fe, Mn, naphthalene, benz[a]anthracene, pyrene, benz[a]pyrene and benzo[k]fluoranthene. On the other hand, AChE activity was not inhibited, which suggests that organophosphorus pollutants or carbamates were absent. Regarding oxidative stress, oysters from the estuary had oxidative damage in lipids, not proteins, and altered antioxidant enzyme activity, when compared to control organisms. Interestingly, we did not observe any correlation between the pollutants and the oxidative stress parameters evaluated in this study. Thus, we cannot rule out that a synergistic effect between the environmental variables and the pollutants is causing the oxidative stress in these oysters.

      PubDate: 2016-09-10T15:33:25Z
  • Usefulness of oxidative stress biomarkers evaluated in the snout scraping,
           serum and Peripheral Blood Cells of Crocodylus moreletii from Southeast
           Campeche for assessment of the toxic impact of PAHs, metals and total
    • Abstract: Publication date: October 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 200
      Author(s): Ricardo Dzul-Caamal, Abigail Hernández-López, Mauricio Gonzalez-Jáuregui, Sergio E. Padilla, Manuel Ivan Girón-Pérez, Armando Vega-López
      In this study, we assessed the effects of inorganic and organic pollutants [As, Cu, Fe, Mn, Pb, Zn, PAHs (11 compounds) and total phenols] from a panel of biomarkers [O2 , H2O2, thiobarbituric acid reactive substances (TBARS), carbonyl proteins (RCO), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and total cytochrome P450 activities] evaluated in the Snout Scraping (SS), Serum (S) and Peripheral Blood Cells (PBC) of the Morelet's crocodile (Crocodylus moreletii) inhabiting the reference locality (Lake Mocu) and polluted locality (Champoton River) using Principal Component Analysis (PCA). In male crocodiles from the reference site, only H2O2 in PBC was related to levels of fluoranthene on the Keel of Caudal Scales (KCS), but, in females, no association was detected. In contrast, a sex-linked response was detected in specimens from the polluted locality. Levels of benzo[a]pyrene, benzo[a]anthracene, chrysene, pyrene, phenanthrene, acenaphthene, Zn, Cu, and Pb in KCS of the female crocodil were related to the oxidative stress biomarkers on PBC, incluing the total CYP450 activity and levels of O2 , H2O2 in serum. However, in male crocodiles, the oxidative stress in SS and in the serum (TBARS, RCO, CAT, GPx), and SOD in PBC was related to As, Pb, Cu, Fe, and benzo[a]pyrene water concentrations and to the burdens of As, Fe, Mn, indeno[1,2,3cd]pyrene in KCS. These results confirm the usefulness of minimal or non-invasive methods of evaluating the oxidative stress response for the environmental monitoring program on the wild Morelet's crocodile that is subject to special protection in Mexican guidelines.

      PubDate: 2016-09-10T15:33:25Z
  • Oxidative stress response in the skin mucus layer of Goodea gracilis
           (Hubbs and Turner, 1939) exposed to crude oil: A non-invasive approach
    • Abstract: Publication date: October 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 200
      Author(s): Ricardo Dzul-Caamal, Lucia Salazar-Coria, Hugo F. Olivares-Rubio, Maria Alejandra Rocha-Gómez, Manuel Iván Girón-Pérez, Armando Vega-López
      The skin of the fish is the foremost target of oxidative stress due to the generation of Reactive Oxygen Species (ROS) originated in the environment and in the skin itself. In this study, a non-destructive assay was developed to evaluate the effects of crude oil (0.0001–0.1mg/L, 96h) on oxidative stress response in the Skin Mucus Layer (SML) of the dusky splitfin goodeid (Goodea gracilis). The response in the SML was compared with recognized target organs through the Integrated Biomarker Response (IBRv2) and a slight addition to the method was proposed. Crude oil was extremely toxic and elicited a clear induction of ROS in the SML, as in the brain, liver and muscle. By the exposure to crude, a significant change in the activities of Superoxide Dismutase (SOD), Catalase (CAT), Glutathione Peroxidase (GPx) as well as on lipid peroxidation (TBARS) and carbonyl protein (RCO) levels was detected. Also, increases in the activity of EROD were found. The general IBRv2 proposed in this study (gIBRv2) showed that oil causes the higher oxidative response in the SML (60.049) under different concentrations of petroleum, which was greater in the brain (56.749), muscle (56.561) and liver (55.775). The results of the study revealed an organ-specific antioxidant defense response that was dependent on the load of petroleum. These results contributed to the understanding of the complexity of oxidative stress response in fish exposed to crude oil using the Skin Mucus Layer as a target for environmental monitoring studies.

      PubDate: 2016-09-10T15:33:25Z
  • Development of functional trait biomarkers for trace metal exposure in
           freshwater clams (Musculium spp.)
    • Abstract: Publication date: October 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 200
      Author(s): Cody M. Schoonover, Jessica Wieker, Rachelle Pope, Chelsea Brown, Emily Cooper, Jariel DeWitt, Samuel Gunselman, Cory Jensen, Whitney Stevens, Jenae Yri, Carmen Nezat, Joanna Joyner-Matos
      Exposure to trace metals typically causes oxidative stress; these consequences are better-characterized in estuarine and marine species than in freshwater species. How cellular-level responses to metal pollution influence whole-organism and population-level traits is poorly understood. We tested whether exposure to single metals (zinc and cadmium) and to metal mixtures (water in equilibrium with sediment from a highly polluted lake) alters two ecologically-relevant traits in freshwater clams, locomotion and reproduction. Fingernail clams (Musculium spp.) from unimpacted habitats were exposed to single metals and the metal mixture for up to 49days. The single metal doses (≤5mg/L Zn and ≤20μg/L Cd) were not toxicologically meaningful as clam survival, burial, and climbing activity did not differ across treatments. Water in equilibrium with the lake sediment contained cadmium, copper, lead, and zinc. Clams exposed to this metal mixture had decreased climbing activity but no change in burial activity. Metal-exposed clams had lower fecundity (number of shelled juveniles extruded by adult clams) and patterns in metal accumulation corresponded with lake sediment dose and clam activity. In contrast to the functional traits, stress protein expression and whole-clam glycogen content did not vary across treatment groups. These results indicate that fingernail clams of the genus Musculium are appropriate for development as sentinel species for metal pollution and can serve as a model for determining how metal pollution alters metabolic allocation patterns in freshwater organisms.

      PubDate: 2016-09-10T15:33:25Z
  • Oxidative stress in aquatic ecosystems: Selected papers from the Second
           International Conference
    • Abstract: Publication date: October 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 200
      Author(s): Joanna Joyner-Matos, Doris Abele, José Pablo Vázquez Medina, Tania Zenteno-Savín

      PubDate: 2016-09-10T15:33:25Z
  • Oxidative damage in gills and liver in Nile tilapia (Oreochromis
           niloticus) exposed to diazinon
    • Abstract: Publication date: October 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 200
      Author(s): G.A. Toledo-Ibarra, K.J.G. Díaz Resendiz, G.H. Ventura-Ramón, F. González-Jaime, A. Vega-López, E. Becerril-Villanueva, L. Pavón, M.I. Girón-Pérez
      Agricultural activity demands the use of pesticides for plague control and extermination. In that matter, diazinon is one of the most widely used organophosphorus pesticides (OPs). Despite its benefits, the use of OPs in agricultural activities can also have negative effects since the excessive use of these substances can represent a major contamination problem for water bodies and organisms that inhabit them. The aim of this paper was to evaluate oxidative damage in lipids and proteins of Nile tilapia (Oreochromis niloticus) exposed acutely to diazinon (0.97, 1.95 and 3.95ppm) for 12 or 24h. The evaluation of oxidative damage was determined by quantifying lipid hydroperoxides (Fox method) and oxidized proteins (DNPH method). The data from this study suggest that diazinon induces a concentration-dependent oxidative damage in proteins, but not lipids, of the liver and gills of Nile tilapia. Furthermore, the treatment leads to a decrease in the concentration of total proteins, which can have serious consequences in cell physiology and fish development.

      PubDate: 2016-09-10T15:33:25Z
  • The expression of nuclear and membrane estrogen receptors in the European
           eel throughout spermatogenesis
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Marina Morini, David S. Peñaranda, M. Carmen Vílchez, Helge Tveiten, Anne-Gaëlle Lafont, Sylvie Dufour, Luz Pérez, Juan F. Asturiano
      Estradiol (E2) can bind to nuclear estrogen receptors (ESR) or membrane estrogen receptors (GPER). While mammals possess two nuclear ESRs and one membrane GPER, the European eel, like most other teleosts, has three nuclear ESRs and two membrane GPERs, as the result of a teleost specific genome duplication. In the current study, the expression of the three nuclear ESRs (ESR1, ESR2a and ESR2b) and the two membrane GPERs (GPERa and GPERb) in the brain-pituitary-gonad (BPG) axis of the European eel was measured, throughout spermatogenesis. The eels were first transferred from freshwater (FW) to seawater (SW), inducing parallel increases in E2 plasma levels and the expression of ESRs. This indicates that salinity has a stimulatory effect on the E2 signalling pathway along the BPG axis. Stimulation of sexual maturation by weekly injections of human chorionic gonadotropin (hCG) induced a progressive decrease in E2 plasma levels, and different patterns of expression of ESRs and GPERs in the BPG axis. The expression of nuclear ESRs increased in some parts of the brain, suggesting a possible upregulation due to a local production of E2. In the testis, the highest expression levels of the nuclear ESRs were observed at the beginning of spermatogenesis, possibly mediating the role of E2 as spermatogonia renewal factor, followed by a sharply decrease in the expression of ESRs. Conversely, there was a marked increase observed in the expression of both membrane GPERs throughout spermatogenesis, suggesting they play a major role in the final stages of spermatogenesis.

      PubDate: 2016-09-10T15:33:25Z
  • Octopamine cyclic release and its modulation of visual sensitivity in
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Leonardo Rodríguez-Sosa, Gabina Calderón-Rosete, Aída Ortega-Cambranis, Francisco F. De-Miguel
      The biogenic amine octopamine (OA) modulates invertebrate behavior by changing neuronal responses from sensory inputs to motor outputs. However, the OA modulation of visual sensitivity and its possible coupling to diurnal cycles remains unexplored. Here we studied the diurnal variations in the OA levels in the hemolymph of the crayfish Procambarus clarkii, its release from the structures in the eyestalk and its modulation of the retinal light sensitivity. The hemolymph concentration of OA and its amino acid precursor tyrosine was measured by high-resolution liquid chromatography; OA varied along the 24-hcycle. The peak value appeared about 2h before the light offset which preceded the peak locomotor activity. OA was found in every structure of the eyestalk but displayed higher levels in the retina–lamina ganglionaris. Moreover, OA was released from isolated eyestalks at a rate of 92nmol/eyestalk/min and a calcium-dependent release was evoked by incubation in a high potassium solution. OA injected into dark-adapted crayfish or applied to the isolated retina at concentrations of 1, 10 and 100μM produced a proportionally increasing reduction in the amplitude of the photoreceptor light responses. These OA concentrations did not affect the position of the visual accessory pigments. Our results suggest that OA release in the crayfish eyestalk is coupled to the 24-hcycle to regulate the diurnal reduction of the photoreceptor sensitivity and to favor the expression of exploratory locomotion during the dark phase of the circadian cycle.

      PubDate: 2016-09-10T15:33:25Z
  • Rumen content stratification in the giraffe (Giraffa camelopardalis)
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Cathrine Sauer, Marcus Clauss, Mads F. Bertelsen, Martin R. Weisbjerg, Peter Lund
      Ruminants differ in the degree of rumen content stratification, with ‘cattle-types’ (i.e., the grazing and intermediate feeding ruminants) having stratified content, whereas ‘moose-types’ (i.e., the browsing ruminants) have unstratified content. The feeding ecology, as well as the digestive morphophysiology of the giraffe (Giraffa camelopardalis), suggest that it is a ‘moose-type’ ruminant. Correspondingly, the giraffe should have an unstratified rumen content and an even rumen papillation pattern. Digesta samples were collected from along the digestive tract of 27 wild-caught giraffes kept in bomas for up to 2months, and 10 giraffes kept in zoological gardens throughout their lives. Samples were analysed for concentration of dry matter, fibre fractions, volatile fatty acids and NH3, as well as mean particle size and pH. There was no difference between the dorsal and ventral rumen region in any of these parameters, indicating homogenous rumen content in the giraffes. In addition to the digesta samples, samples of dorsal rumen, ventral rumen and atrium ruminis mucosa were collected and the papillary surface enlargement factor was determined, as a proxy for content stratification. The even rumen papillation pattern observed also supported the concept of an unstratified rumen content in giraffes. Zoo giraffes had a slightly more uneven papillation pattern than boma giraffes. This finding could not be matched by differences in physical characteristics of the rumen content, probably due to an influence of fasting time ante mortem on these parameters.

      PubDate: 2016-09-10T15:33:25Z
  • Metabolic responses to chronic hypoxic incubation in embryonic American
           alligators (Alligator mississippiensis)
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Dane A. Crossley, Rick Ling, Derek Nelson, Taylor Gillium, Justin Conner, James Hapgood, Ruth M. Elsey, John Eme
      Chronic hypoxic incubation is a common tool used to study developmental changes in reduced O2 conditions, and it has been useful for identifying phenotypically plastic periods during ontogeny in laboratory settings. Reptilian embryos can be subjected to natural hypoxia due to nesting strategy, and recent studies have been important in establishing the phenotypic responses of several species to low developmental oxygen. In particular, the cardiovascular responses of American alligators (Alligator mississippiensis) to low developmental oxygen have been detailed, including a substantial cardiac enlargement that may support a higher mass specific metabolic rate. However, embryo mass-specific metabolic demands of hypoxic incubated alligator embryos have not been measured. In this study, alligator eggs were incubated in 10% O2 (H) or 21% O2 (N) environments for the entire course of embryonic development. Acute metabolic measures in 21% and 10% O2 were taken for both H and N groups. We hypothesized that acute 10% O2 exposure has no impact on metabolic rate of embryonic alligators, and that metabolic rate is unaffected by chronic hypoxic incubation when studied in embryos measured at 21% O2. Our findings suggest phenotypic changes resulting from hypoxic incubation early in incubation, in particular relative cardiac enlargement, enable embryonic alligators to sustain metabolic rate during acute hypoxic exposure.

      PubDate: 2016-09-10T15:33:25Z
  • The expression of VILL protein is hypoosmotic-dependent in the lamellar
           gill ionocytes of Otocephala teleost fish, Chanos chanos
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Chao-Kai Kang, Chia-Shian Lin, Yao-Chung Hu, Shu-Chuan Tsai, Tsung-Han Lee
      Milkfish, a species within the primitive teleost lineage Otocephala, can survive in water conditions ranging from hypo- to hyper-saline. This study explored the effects of environmental salinity on apical morphologies of ionocytes and the expression of villin homologs in the gills of milkfish acclimated to either seawater (SW) or fresh water (FW). Scanning electron microscopy revealed that the ionocytes in the gill filaments of SW and FW milkfish, respectively, cellular apical morphologies were hole-type and squint-type. The flat-type ionocytes were observed in the gill lamellae of FW milkfish. Furthermore, apical surfaces of some lamellar ionocytes exhibited microvilli. Villin 1 is a microvilli marker expressed in the epithelial cells of various vertebrates. In the phylogenetic tree of villin 1 homologs, primitive teleosts exhibit villin 1-like (VILL) and villin 1 proteins. Two mRNA sequences, villin 1 and VILL, were identified from the milkfish transcriptome by next generation sequencing. Low but constant expression of villin 1 (gene and protein) was observed in the gills for both SW and FW fish. VILL gene and protein expression levels in the gills were higher in FW fish, compared to SW fish. Double immunofluorescence staining demonstrated that VILL protein was present in some lamellar ionocytes of FW milkfish, but not in the filament ionocytes of either FW or SW milkfish. Taken together, these findings indicated that the VILL expression of ionocytes is hypoosmotic-dependent. The VILL might be involved in the formation of microvilli in the lamellar ionocytes for hyperosmoregulation of the milkfish.

      PubDate: 2016-09-05T15:15:08Z
  • The contribution of heart rate to the oxygen consumption of the chicken
           embryo during cold- or hypoxia-hypometabolism
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Satoko Tomita Ide, Ryoji Ide, Jacopo P. Mortola
      In embryos, cooling and hypoxia cause a decrease in oxygen consumption ( V ̇ O 2 ); we asked what was the relative contribution of heart rate (HR) and of the ‘not-HR’ factor (the product of stroke volume and arterial-venous O2 difference) to the drop in V ̇ O 2 . Data of HR (with subcutaneous electrodes) and V ̇ O 2 (by an open-flow methodology) were collected simultaneously on chicken embryos close to end-incubation. Over the last four days of incubation (E16–E20) differences in HR contributed about 30% of the differences in resting V ̇ O 2 among embryos. At E20, progressive cooling from 38 to 8°C decreased V ̇ O 2 entirely because of the decrease in HR, with minimal compensation of the ‘not-HR’ component. The same pattern during cooling occurred in younger embryos (age E16), in E20 embryos simultaneously exposed to hypoxia (15% O2) and in E20 normoxic embryos which were incubated in hypoxia (15% O2). Differently, in E20 embryos in normothermia, progressive hypoxia (15%, 10% or 5% O2) lowered V ̇ O 2 largely because of the reduction in the ‘not-HR’ component. We conclude that at end incubation during hypometabolism the changes in HR contribute very differently to the decrease in V ̇ O 2 , from about the totality of it during cold to only about 10–20% during hypoxia, depending on its severity. It follows that during cold-hypometabolism, but not during hypoxic hypometabolism, the changes in HR are a good index of the changes in V ̇ O 2 . The close relationship between V ̇ O 2 and HR during cold-hypometabolism may permit estimates of the changes in V ̇ O 2 from the changes in HR in infants undergoing therapeutic hypothermia.

      PubDate: 2016-09-05T15:15:08Z
  • Characterization of the peripheral thyroid system of gilthead seabream
           acclimated to different ambient salinities
    • Abstract: Publication date: Available online 21 August 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): I. Ruiz-Jarabo, P.H.M. Klaren, B. Louro, J.A. Martos-Sitcha, P.I.S. Pinto, L. Vargas-Chacoff, G. Flik, G. Martinez-Rodriguez, D.M. Power, J.M. Mancera, F.J. Arjona
      Thyroid hormones are involved in many developmental and physiological processes, including osmoregulation. The regulation of the thyroid system by environmental salinity in the euryhaline gilthead seabream (Sparus aurata) is still poorly characterized. To this end seabreams were exposed to four different environmental salinities (5, 15, 40 and 55ppt) for 14days, and plasma free thyroid hormones (fT3, fT4), outer ring deiodination and Na+/K+-ATPase activities in gills and kidney, as well as other osmoregulatory and metabolic parameters were measured. Low salinity conditions (5ppt) elicited a significant increase in fT3 (29%) and fT4 (184%) plasma concentrations compared to control animals (acclimated to 40ppt, natural salinity conditions in the Bay of Cádiz, Spain), while the amount of pituitary thyroid stimulating hormone subunit β (tshb) transcript abundance remained unchanged. In addition, plasma fT4 levels were positively correlated to renal and branchial deiodinase type 2 (dio2) mRNA expression. Gill and kidney T4-outer ring deiodination activities correlated positively with dio2 mRNA expression and the highest values were observed in fish acclimated to low salinities (5 and 15ppt). The high salinity (55ppt) exposure caused a significant increase in tshb expression (65%), but deiodinase gene expression (dio1 and dio2) and activity did not change and were similar to controls (40ppt). In conclusion, acclimation to different salinities led to changes in the peripheral regulation of thyroid hormone metabolism in seabream. Therefore, thyroid hormones are involved in the regulation of ion transport and osmoregulatory physiology in this species. The conclusions derived from this study may also allow aquaculturists to modulate thyroid metabolism in seabream by adjusting culture salinity.

      PubDate: 2016-08-26T13:17:08Z
  • Physiological effects of hypoxic conditions during the plateau period on
           the chicken embryo
    • Abstract: Publication date: Available online 21 August 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): A. Haron, Y. Dahan, D. Shinder, S. Druyan
      The chick embryo employs several adaptive responses to hypoxic challenges, affecting both metabolism and oxygen (O2) transport. The present study assessed the effects of hypoxic conditions (17% O2) during the plateau phase on embryonic metabolic rate, cardiovascular parameters, and development up to hatching. The study was divided into 2 experiments: (1) Control; 17% O2 for 6h/d on E16–E18 (6H), and 17% O2 for 12h/d on E16–E18 (12H), and (2) Control; 12H, and 17% O2 continuously for 72h on E16–E18, (72H). Hypoxic embryos exhibited a significant increase in heart rate and an upward trend starting on E17 in hematocrit and hemoglobin levels. We observed a decrease in metabolism in 12H and 72H embryos during the plateau period; their oxygen consumption as well as yolk consumption were lower compared to Control and they hatched with a significantly lower body temperature, indicating lower heat production. There was no evidence of adaptation or long-term effects of exposure to 17% O2 for 6h/d. Exposure to 72h of hypoxic conditions led to significant physiological changes and had a detrimental influence on embryonic development and growth. In contrast, exposure to 12h/d produced moderate hypoxic changes, which helped the embryo to cope with the stress without significant influences on its growth and development. The decrease in metabolism may represent a metabolic adaptation through a decrease in resting metabolic rate and lower heat production. Such alterations may affect post-hatch performance and energy allocation between maintenance and growth, especially under stress when there is increased oxygen demand.

      PubDate: 2016-08-26T13:17:08Z
  • Dietary carbohydrates improve oxidative status of common dentex (Dentex
           dentex) juveniles, a carnivorous fish species
    • Abstract: Publication date: Available online 21 August 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Amalia Pérez-Jiménez, Emilia Abellán, Marta Arizcun, Gabriel Cardenete, Amalia E. Morales, M. Carmen Hidalgo
      Common dentex (Dentex dentex) is an appreciated carnivorous fish with high growth rate and life cycle adaptable to existing farming techniques. Since the use of carbohydrates is an economic and sustainable alternative for a protein-sparing effect, the study of how this macronutrient affects the welfare of carnivorous species must be studied. The aim of the present study was to evaluate the effects of different types and levels of carbohydrates on common dentex oxidative status. Nine isonitrogenous (43%) and isoenergetic (22MJkg−1) diets were formulated combining three types (pregelatinized starch-PS, dextrin-Dx and maltodextrin-Mx) and three levels (12, 18 and 24%) of carbohydrates. The activities of catalase-CAT, superoxide dismutase-SOD, glutathione peroxidase-GPX, glutathione reductase-GR and glucose 6-phosphate dehydrogenase-G6PDH, SOD isoenzymatic profile, lipid peroxidation-LPO and protein oxidation-PO were determined in liver and white muscle. SOD and CAT were not affected. GPX in liver and white muscle and GR in liver increased at higher inclusion carbohydrates levels. The lowest levels of GR and G6PDH in both tissues and LPO in liver were observed in maltodextrin groups. No significant effects by carbohydrate source were observed in liver PO and white muscle LPO. Regarding carbohydrate level effect, 18% and 24% dietary inclusion level decreased LPO in white muscle and PO in liver. LPO in liver was also decreased at 24% inclusion level. Altogether, results indicate the use of carbohydrates as an alternative energy source does not produce negative effects on oxidative status of common dentex, on the contrary, even contribute to their oxidative protection.

      PubDate: 2016-08-21T12:53:52Z
  • 1 Effects of Echinostoma trivolvis metacercariae infection during
           development and metamorphosis of the wood frog (Lithobates sylvaticus)
    • Abstract: Publication date: Available online 17 August 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Sarah A. Orlofske, Lisa K. Belden, William A. Hopkins
      Many organisms face energetic trade-offs between defense against parasites and other host processes that may determine overall consequences of infection. These trade-offs may be particularly evident during unfavorable environmental conditions or energetically demanding life history stages. Amphibian metamorphosis, an ecologically important developmental period, is associated with drastic morphological and physiological changes and substantial energetic costs. Effects of the trematode parasite Echinostoma trivolvis have been documented during early amphibian development, but effects during later development and metamorphosis are largely unknown. Using a laboratory experiment, we examined the energetic costs of late development and metamorphosis coupled with E. trivolvis infection in wood frogs, Lithobates [=Rana] sylvaticus. Echinostoma infection intensity did not differ between tadpoles examined prior to and after completing metamorphosis, suggesting that metacercariae were retained through metamorphosis. Infection with E. trivolvis contributed to a slower growth rate and longer development period prior to the initiation of metamorphosis. In contrast, E. trivolvis infection did not affect energy expenditure during late development or metamorphosis. Possible explanations for these results include the presence of parasites not interfering with pronephros degradation during metamorphosis or the mesonephros compensating for any parasite damage. Overall, the energetic costs of metamorphosis for wood frogs were comparable to other species with similar life history traits, but differed from a species with a much shorter duration of metamorphic climax. Our findings contribute to understanding the possible role of energetic trade-offs between parasite defense and host processes by considering parasite infection with simultaneous energetic demands during a sensitive period of development.

      PubDate: 2016-08-17T12:40:02Z
  • The metabolic consequences of repeated anoxic stress in the western
           painted turtle, Chrysemys picta bellii
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Daniel E. Warren, Donald C. Jackson
      The painted turtle is known for its extreme tolerance to anoxia, but it is unknown whether previous experience with anoxic stress might alter physiological performance during or following a test bout of anoxia. Repeatedly subjecting 25°C-acclimated painted turtles to 2h of anoxic stress every other day for 19days (10 submergence bouts total) caused resting levels of liver glycogen to decrease by 17% and liver citrate synthase (CS) and cytochrome oxidase (COX) activities to increase by 33% and 112%, respectively. When the repeatedly submerged turtles were studied during a subsequent anoxic stress test, liver COX and CS activities decreased during anoxia to the same levels of naïve turtles, which were unchanged, and remained there throughout metabolic recovery. There were no effects of the repeated anoxia treatment on any of the other measured variables, which included lactate dehydrogenase and phosphofructokinase activities in liver, skeletal muscle, and ventricle, blood acid-base status, hemoglobin, hematocrit and plasma ion (Na, K, Ca, Mg, Cl) and metabolite concentrations (lactate, glucose, free-fatty acids), before, during, or after the anoxic stress test. We conclude that although painted turtles can show a physiological reaction to repeated anoxic stress, the changes appear to have no measurable effect on anaerobic physiological performance or ability to recover from anoxia.

      PubDate: 2016-08-12T12:14:02Z
  • Molecular cloning of kisspeptin receptor genes (gpr54-1 and gpr54-2) and
           their expression profiles in the brain of a tropical damselfish during
           different gonadal stages
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Satoshi Imamura, Sung-Pyo Hur, Yuki Takeuchi, Selma Bouchekioua, Akihiro Takemura
      The kisspeptin receptor (GPR54) mediates neuroendocrine control of kisspeptin in the brain and acts as a gateway for a pulsatile release of hypothalamic gonadotropin-releasing hormone. This study aimed to clone two GPR54 genes (gpr54-1 and gpr54-2) from the brain of the sapphire devil Chrysiptera cyanea, a tropical damselfish, and to study their involvement in reproduction. The partial sequences of the sapphire devil gpr54-1 cDNA (1059bp) and gpr54-2 cDNA (1098bp) each had an open reading frame encoding a protein of 353 and 366 amino acids, respectively, both of which had structural features of a G-protein-coupled receptor. The expression of gpr54-1 mRNA was observed in the diencephalon and telencephalon, and gpr54-2 mRNA was found in the optic tectum of sapphire devil. When gpr54-1 and gpr54-2 mRNA levels were examined in the brain of sapphire devil by real-time quantitative polymerase chain reaction (qPCR), they were found to increase during late vitellogenesis and post-spawning. Treatment of fish with estradiol-17β (Ε2) resulted in an increase in gpr54-1 and gpr54-2 expression in the brain of sapphire devil. Thus, kisspeptin receptors likely mediate the activity of kisspeptin in the brain and are involved in controlling reproductive events in a tropical damselfish.

      PubDate: 2016-08-12T12:14:02Z
  • Dietary antioxidants enhance immunocompetence in larval amphibians
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Dorina Szuroczki, Janet Koprivnikar, Robert L. Baker
      Dietary antioxidants have been shown to confer a variety of benefits through their ability to counter oxidative stress, including increased immunocompetence and reduced susceptibility to both infectious and non-infectious diseases. However, little is known about the effects of dietary antioxidants on immune function in larval amphibians, a group experiencing worldwide declines driven by factors that likely involve altered immunocompetence. We investigated the effects of dietary antioxidants (quercetin, vitamin E, and β-carotene) on two components of the immune system, as well as development and growth. Lithobates pipiens tadpoles fed diets with supplemental β-carotene or vitamin E exhibited an enhanced swelling response as measured with a phytohemagglutinin assay (PHA), but there was no induced antibody response. Effects were often dose-dependent, with higher antioxidant levels generally conferring stronger swelling that possibly corresponds to the innate immune response. Our results indicate that the antioxidant content of the larval amphibian diets not only had a detectable effect on their immune response capability, but also promoted tadpole growth (mass gain), although developmental stage was not affected. Given that many environmental perturbations may cause oxidative stress or reduce immunocompetence, it is critical to understand how nutrition may counter these effects.

      PubDate: 2016-08-07T11:31:03Z
  • Dietary glucose stimulus at larval stage modifies the carbohydrate
           metabolic pathway in gilthead seabream (Sparus aurata) juveniles: An in
           vivo approach using 14C-starch
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Filipa Rocha, Jorge Dias, Inge Geurden, Maria Teresa Dinis, Stephane Panserat, Sofia Engrola
      The concept of nutritional programming was investigated in order to enhance the use of dietary carbohydrates in gilthead seabream juveniles. We assessed the long-term effects of high-glucose stimuli, exerted at the larval stage, on the growth performance, nutrient digestibility and metabolic utilization and gene expression of seabream juveniles, challenged with a high-carbohydrate intake. During early development, a group of larvae (control, CTRL) were kept under a rich-protein-lipid feeding regime whereas another group (GLU) was subjected to high-glucose stimuli, delivered intermittently over time. At juvenile stage, triplicate groups (IBW: 2.5g) from each fish nutritional background were fed a high-protein (59.4%) low-carbohydrate (2.0%) diet before being subjected to a low-protein (43.0%) high-carbohydrate (33.0%) dietary challenge for 36-days. Fish from both treatments increased by 8-fold their initial body weight, but neither growth rate, feed intake, feed and protein efficiency, nutrient retention (except lipids) nor whole-body composition were affected (P ˃0.05) by fish early nutritional history. Nutrient digestibility was also similar among both groups. The metabolic fate of 14C-starch and 14C-amino acids tracers was estimated; GLU juveniles showed higher absorption of starch-derived glucose in the gut, suggesting an enhanced digestion of carbohydrates, while amino acid use was not affected. Moreover, glucose was less used for de novo synthesis of hepatic proteins and muscle glycogen from GLU fish (P <0.05). Our metabolic data suggests that the early glucose stimuli may alter carbohydrate utilization in seabream juveniles.

      PubDate: 2016-08-07T11:31:03Z
  • The increase in fat content in the warm-acclimated striped hamsters is
           associated with the down-regulated metabolic thermogenesis
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Song Tan, Jing Wen, Lu-Lu Shi, Chun-Ming Wang, Gui-Ying Wang, Zhi-Jun Zhao
      It has been well known that metabolic thermogenesis plays an important role in the thermoregulation of small mammals under different temperatures, while its role in fat accumulation is far from clear. In the present study, several physiological, hormonal, and biochemical measures indicative of metabolic thermogenesis were measured in the weaning striped hamsters after acclimated to a warm condition (30°C) for 1, 3 and 4months. The warm-acclimated groups significantly decreased energy intake, and simultaneously decreased nonshivering thermogenesis compared to those housed at 21°C. Body fat content increased by 29.9%, 22.1% and 19.6% in the hamsters acclimated to 1, 3 or 4months, respectively relative to their counterparts maintain at 21°C (P <0.05). The cytochrome c oxidase (COX) activity of brain, liver, heart and skeletal muscle, and the ratio of serum tri-iodothyronine to thyroxine significantly decreased in warm-acclimated groups compared with 21°C group. COX activity and uncoupling protein 1 (UCP1) mRNA expression of brown adipose tissue (BAT) were significantly down-regulated under the warm conditions. COX activity of BAT, liver, heart and muscle were significantly negatively correlated with body fat content, and the correlation between UCP1 expression and body fat content tended to be negative. These findings suggest that the decrease in the energy spent on metabolic thermogenesis plays an important role in the fat accumulation. The attenuation of COX and UCP1-based BAT activity may be involved in body fat accumulation in animals under warm conditions.

      PubDate: 2016-08-03T10:43:25Z
  • The response of two species of unionid mussels to extended exposure to
           elevated carbon dioxide
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Kelly D. Hannan, Jennifer D. Jeffrey, Caleb T. Hasler, Cory D. Suski
      Changes in environmental conditions can act as stressors, with potential consequences for the health and fitness of organisms. Rising levels of carbon dioxide (CO2) is one potential environmental stressor that is occurring more frequently in the environment and can be a stressor for aquatic organisms. In this study, the physiological responses of two species of unionid mussel, Lampsilis siliquoidea and Amblema plicata, were assessed in response to exposure to two levels of elevated partial pressure of CO2 (pCO2) (~20,000 and ~55,000μatm) over a 28d period, followed by a subsequent 14d recovery period. Observations were consistent with responses associated with respiratory acidosis, as demonstrated by changes in hemolymph HCO3 −, Ca2+, Cl−, and Na2+. Both species exposed to elevated pCO2 had elevated hemolymph HCO3 – during the pCO2 treatment period compared to control mussels, but recovered once pCO2 was removed. Similarly, both species had elevated hemolymph Na+ during exposure to elevated pCO2, and this returned to control levels for A. plicata but remained elevated for L. siliquoidea once the pCO2 stimuli was removed. Changes in hemolymph Ca2+ and Cl− in response to elevated pCO2 were also observed, but these changes were species-specific. Additional physiological responses to elevated pCO2 (e.g., changes in hemolymph glucose and Mg2+) were consistent with a stress response in both species. This study demonstrates the importance of considering inter-specific differences in the response of organisms to stress, and also that responses to elevated pCO2 may be transient and can recover once the stress is removed.

      PubDate: 2016-08-03T10:43:25Z
  • Acute hyperthermic responses of heat shock protein and estrogen receptor
           mRNAs in rainbow trout hepatocytes
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Yudong Jia, Timothy D. Cavileer, James J. Nagler
      Heat shock proteins (HSPs) are induced upon elevated temperature in fishes. HSPs also function as molecular chaperones for cellular proteins, including steroid hormone receptors. Estrogen receptors (ERs) are critical for the hormone signaling necessary during the liver production of the yolk precursor protein vitellogenin in oviparous vertebrates. Considering the possible regulatory role of HSPs on the ER signaling pathway, the present study characterized the mRNA expression of all known isoforms of HSP70 (hsp70a, hsp70b), HSP90 (hsp90a1a, hsp90a1b, hsp90a2a, hsp90a2b, hsp90b1, hsp90b2), and ERs (erα1, erα2, erβ1, erβ2) in Rainbow Trout hepatocytes following an acute heat shock (1h at 25°C) compared to a control treatment (12°C). The results showed that the mRNA levels of hsp70a, hsp70b, hsp90a1b, hsp90a2a, and hsp90b2 were significantly increased after heat shock, while erα1 mRNA levels were significantly reduced by this treatment. hsp90a1a, hsp90a2b, hsp90b1, erα2, erβ1 and erβ2 were unaffected by this acute hyperthermic treatment. Comparatively, the responses of the two hsp70 isoforms were much greater than the hsp90 isoforms. Acute heat shock treatment of hepatocytes followed by a 24h exposure to 17β-estradiol (E2) exposure also resulted in decreased expression of erα1 mRNA, but not vitellogenin (vtg) mRNA. This study showed that some hsp70 and hsp90 isoforms display a robust response to an acute hyperthermic treatment in Rainbow Trout hepatocytes. Among the transcripts measured here, the erα1 isoform uniquely showed significantly decreased mRNA levels upon acute heat treatment.

      PubDate: 2016-08-03T10:43:25Z
  • A fatty acyl desaturase (fads2) with dual Δ6 and Δ5 activities from the
           freshwater carnivorous striped snakehead Channa striata
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Meng-Kiat Kuah, Annette Jaya-Ram, Alexander Chong Shu-Chien
      There is a lack of understanding on how the environment and trophic niche affect the capability of long-chain polyunsaturated fatty acids (LC-PUFA) in freshwater carnivorous teleost. In this present study, we isolated and functionally characterised a fatty acyl desaturase (Fads) from the striped snakehead Channa striata. Sequence comparison and phylogenetic analysis suggested a Fads2 protein that is closely related to previously characterised Fads2 proteins from freshwater carnivorous and marine herbivorous fish species. We further demonstrated the capacity of Δ6 and Δ5 desaturation activities for this particular desaturase, with highest activities towards the conversion of omega-3 (n-3) polyunsaturated fatty acids (PUFA). Low Δ4 desaturation activity was also detected, although the significance of this at a physiological level remains to be studied. The expression of this striped snakehead Δ6/Δ5 fads2 gene was highest in brain, followed by liver and intestine. In liver, diet fortified with high LC-PUFA concentration impeded the expression of Δ6/Δ5 fads2 gene compared to vegetable oil (VO) based diets. The discovery of Δ6/Δ5 Fads2 desaturase here complements the previous discovery of a Δ4 Fads2 desaturase and an Elovl5 elongase, lending proof to the existence of all the required enzymatic machinery to biosynthesise LC-PUFA from C18 PUFA in a freshwater carnivorous species.

      PubDate: 2016-08-03T10:43:25Z
  • High glucose impairs acetylcholine-mediated vasodilation in isolated
           arteries from Mourning doves (Z. macroura)
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Catherine L. Jarrett, Zoha Ahmed, James J. Faust, Karen L. Sweazea
      Normal avian plasma glucose levels are 1.5–2 times greater than mammals of similar size. In mammals, hyperglycemia induces oxidative stress and impaired endothelium-dependent vasodilation. Prior work has shown that mourning doves have high levels of antioxidants and isolated vessels have low endogenous oxidative stress. Therefore, the hypothesis was that endothelium-dependent vasodilation of isolated avian arteries would not be impaired following acute exposure to high glucose. Isolated small resistance cranial tibial arteries (c. tibial) were cannulated and pressurized in a vessel chamber then incubated with either normal or high glucose (20mM vs. 30mM) for 1h at 41°C. Vessels were then pre-constricted to 50% of resting inner diameter with phenylephrine (PE) followed by increasing doses of acetylcholine (ACh; 10−9 to 10−5 M, 5min per step). Percent vasodilation was measured by tracking the inner diameter with edge-detection software. Contrary to our hypothesis, ACh-induced vasodilation was impaired with acute exposure to high glucose (p=0.013). The impairment was not related to increased osmolarity since vasodilation of arteries exposed to an equimolar combination of 20mM d-glucose and 10mM l-glucose was not different from controls (p=0.273). Rather, the impaired vasodilation was attributed to oxidative stress since superoxide levels were elevated 168±42% (p=0.02) and pre-exposure of arteries to the superoxide dismutase mimetic tiron (10mM) improved vasodilation (p<0.05). Therefore, isolated arteries from doves do not have endogenous mechanisms to prevent impaired vasodilation resulting from high glucose-mediated increases in oxidative stress.

      PubDate: 2016-08-03T10:43:25Z
  • Regulation of sex steroid production and mRNAs encoding gonadotropin
           receptors and steroidogenic proteins by gonadotropins, cyclic AMP and
           insulin-like growth factor-I in ovarian follicles of rainbow trout
           (Oncorhynchus mykiss) at two stages of vitellogenesis
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Ikumi Nakamura, Makoto Kusakabe, Penny Swanson, Graham Young
      At the completion of vitellogenesis, the steroid biosynthetic pathway in teleost ovarian follicles switches from estradiol-17β (E2) to maturational progestin production, associated with decreased follicle stimulating hormone (Fsh) and increased luteinizing hormone (Lh) signaling. This study compared effects of gonadotropins, human insulin-like growth factor-I (IGF1), and cAMP/protein kinase A signaling (forskolin) on E2 production and levels of mRNAs encoding steroidogenic proteins and gonadotropin receptors using midvitellogenic (MV) and late/postvitellogenic (L/PV) ovarian follicles of rainbow trout. Fsh, Lh and forskolin, but not IGF1, increased testosterone and E2 production in MV and L/PV follicles. Fsh increased steroidogenic acute regulatory protein (star; MV), 3β-hydroxysteroid dehydrogenase/Δ 5−4 isomerase (hsd3b; MV) and P450 aromatase (cyp19a1a; MV) transcript levels. Lh increased star mRNA levels (MV, L/PV) but reduced cyp19a1a transcripts in L/PV follicles. At both follicle stages, IGF1 reduced levels of hsd3b transcripts. In MV follicles, IGF1 decreased P450 side-chain cleavage enzyme (cyp11a1) transcripts but increased cyp19a1a transcripts. In MV follicles only, forskolin increased star and hsd3b transcripts. Forskolin reduced MV follicle cyp11a1 transcripts and reduced cyp19a1a transcripts in follicles at both stages. Fsh and Lh reduced fshr transcripts in L/PV follicles. Lh also reduced lhcgr transcripts (L/PV). IGF1 had no effect on gonadotropin receptor transcripts. Forskolin reduced MV follicle fshr transcript levels and reduced lhcgr transcripts in L/PV follicles. These results reveal hormone- and stage-specific transcriptional regulation of steroidogenic protein and gonadotropin receptor genes and suggest that the steroidogenic shift at the completion of vitellogenesis involves loss of stimulatory effects of Fsh and Igfs on cyp19a1a expression and inhibition of cyp19a1a transcription by Lh.

      PubDate: 2016-08-03T10:43:25Z
  • Characterization of developmental Na+ uptake in rainbow trout larvae
           supports a significant role for Nhe3b
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): David Boyle, Salvatore D. Blair, Danuta Chamot, Greg G. Goss
      Developing freshwater fish must compensate for the loss of ions, including sodium (Na+), to the environment. In this study, we used a radiotracer flux approach and pharmacological inhibitors to investigate the role of sodium/hydrogen exchange proteins (Nhe) in Na+ uptake in rainbow trout (Oncorhynchus mykiss) reared from fertilization in soft water (0.1mM Na+). For comparison, a second group of embryos/larvae reared in hard water (2.2mM Na+, higher pH and [Ca2+]) were also included in the experiment but were fluxed in soft water, only. Unidirectional rates of Na+ uptake increased throughout development and were significantly higher in embryos/larvae reared in soft water. However, the mechanisms of Na+ uptake in both groups of larvae were not significantly different, either in larvae immediately post-hatch or later in development: the broad spectrum Na+ channel blocker amiloride inhibited 85–90% of uptake and the Nhe-inhibitor EIPA also caused near maximal inhibitions of Na+ uptake. These data indicated Na+ uptake was Nhe-mediated in soft water. A role of Nhe3b (but not Nhe2 or Nhe3a) in Na+ uptake in soft water was also supported through gene expression analyses: expression of nhe3b increased throughout development in whole embryos/larvae in both groups and was significantly higher in those reared in soft water. This pattern of expression correlated well with measurements of Na+ uptake. Together these data indicate that in part, rainbow trout embryos/larvae reared in low Na+ soft water maintained Na+ homeostasis by an EIPA sensitive component of Na+ uptake, and support a primary role for Nhe3b.

      PubDate: 2016-08-03T10:43:25Z
  • Volume regulation of intestinal cells of echinoderms: Putative role of ion
           transporters (Na+/K+-ATPase and NKCC)
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Giovanna C. Castellano, Marta M. Souza, Carolina A. Freire
      Echinoderms are exclusively marine osmoconformer invertebrates. Some species occupy the challenging intertidal region. Upon salinity changes, the extracellular osmotic concentration of these animals also varies, exposing tissues and cells to osmotic challenges. Cells and tissues may then respond with volume regulation mechanisms, which involve transport of ions and water into and/or out of the cells, through ion transporters, such as the Na+/K+-ATPase and NKCC. The goal of this study was to relate the cell volume regulation capacity of echinoderm intestinal cells Na+/K+-ATPase and NKCC activities, in three echinoderm species: Holothuria grisea, Arbacia lixula, and Echinometra lucunter. Isolated cells of these species displayed some control of their cell volume upon exposure to anisosmotic media (isolated intestinal cells, calcein fluorescence as indicator of volume change), with a distinct higher capacity shown by H. grisea, which did not swell even upon 50% hyposmotic shock. The holothuroid cells showed indirect evidence (effect of furosemide) of the participation of NKCC in this process, with a secretory function, and of a secondary role by the NKA (effect of ouabain). Other mechanisms are probably responsible for this function in the urchins. Variable expression of these transporters, and others not examined here, may to some extent account for the variability in cell volume regulation capacity in echinoderm cells.

      PubDate: 2016-08-03T10:43:25Z
  • Combined effects of dietary polyunsaturated fatty acids and parasite
           exposure on eicosanoid-related gene expression in an invertebrate model
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Nina Schlotz, Anne Roulin, Dieter Ebert, Dominik Martin-Creuzburg
      Eicosanoids derive from essential polyunsaturated fatty acids (PUFA) and play crucial roles in immunity, development, and reproduction. However, potential links between dietary PUFA supply and eicosanoid biosynthesis are poorly understood, especially in invertebrates. Using Daphnia magna and its bacterial parasite Pasteuria ramosa as model system, we studied the expression of genes coding for key enzymes in eicosanoid biosynthesis and of genes related to oogenesis in response to dietary arachidonic acid and eicosapentaenoic acid in parasite-exposed and non-exposed animals. Gene expression related to cyclooxygenase activity was especially responsive to the dietary PUFA supply and parasite challenge, indicating a role for prostanoid eicosanoids in immunity and reproduction. Vitellogenin gene expression was induced upon parasite exposure in all food treatments, suggesting infection-related interference with the host's reproductive system. Our findings highlight the potential of dietary PUFA to modulate the expression of key enzymes involved in eicosanoid biosynthesis and reproduction and thus underpin the idea that the dietary PUFA supply can influence invertebrate immune functions and host-parasite interactions.

      PubDate: 2016-08-03T10:43:25Z
  • Variation in winter metabolic reduction between sympatric amphibians
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Luděk Podhajský, Lumír Gvoždík
      Distribution and abundance of temperate ectotherms is determined, in part, by the depletion of their limited caloric reserves during wintering. The magnitude of winter energy drain depends on the species-specific capacity to seasonally modify the minimal maintenance costs. We examined seasonal variation of minimum oxygen consumption between two newt species, Ichthyosaura alpestris and Lissotriton vulgaris. Oxygen consumption was measured in both species during their active season (daily temperature range=12–22°C) and wintering period (4°C) at 4°C and 8°C. The seasonal reduction in metabolic rates differed between species and experimental temperatures. Wintering newts reduced their metabolic rates at 4°C and 8°C in I. alpestris, but only at 8°C in L. vulgaris. Both species reduced the thermal sensitivity of oxygen consumption during wintering. Theoretical calculations of winter depletion of caloric reserves under various thermal conditions revealed that seasonal metabolic reduction is more effective in I. alpestris than in L. vulgaris, and its effectiveness will increase with the proportion of warmer days during wintering period. The variation in winter metabolic reduction between sympatric newt species potentially contributes to their distribution patterns and population dynamics under climate change.

      PubDate: 2016-08-03T10:43:25Z
  • Predicting transport survival of brindle and red rock lobsters Jasus
           edwardsii using haemolymph biochemistry and behaviour traits
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Cedric J. Simon, Tania C. Mendo, Bridget S. Green, Caleb Gardner
      Mortality events during live transport of Jasus edwardsii rock lobsters are common around the time of season openings in Tasmania, with lobsters from deeper fishing areas with pale shell colouration (brindle) being perceived as more susceptible than shallow-water, red-coloured (red) lobsters. The aims of this study were to assess and predict the vulnerability of brindle and red lobsters to extended emersion exposure using pre- and post-emersion data which included 28 haemolymph biochemical parameters and 5 behaviour traits. No effect of lobster shell colour on haemolymph biochemistry, behaviour traits and their vulnerability to emersion was found. A combined survival of 97% after 40h and 57% after 64h in a first experiment, and 37% after 64h in a second experiment, was observed. Behaviour traits (i.e., righting response, tail flips and three reflex behaviours) were poor indicator of survival. Haemolymph parameters were either unaffected by emersion (e.g., Brix index, protein and lipids), affected by emersion but not associated with mortality (e.g., total haemocyte counts, calcium, magnesium, bicarbonate, glucose and uric acid), or associated with mortality following a recovery period (e.g., pH, the sodium to potassium ratio, urea, and the activity of amylase). A build-up of anaerobic end-products and nitrogenous waste most likely resulted in the mortality. A model based on lobster size and the pre-emersion concentration of haemolymph bicarbonate and haemocyanin was found to be a useful indicator of future survival. This study provides promising leads towards the development of a blood based vulnerability test for live crustacean prior transport.

      PubDate: 2016-08-03T10:43:25Z
  • Hypoxia-reoxygenation differentially alters the thermal sensitivity of
           complex I basal and maximal mitochondrial oxidative capacity
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): John O. Onukwufor, Fred Kibenge, Don Stevens, Collins Kamunde
      Hypoxia-reoxygenation (H-R) transitions and temperature fluctuations occur frequently in biological systems and likely interact to alter cell function. To test how H-R modulates mitochondrial function at different temperatures we measured the effects of H-R on isolated fish liver mitochondrial oxidation rates over a wide temperature range (5–25°C). Subsequently, the mechanisms underlying H-R induced mitochondrial responses were examined. H-R inhibited the complex I (CI) maximal (state 3) and stimulated the basal (state 4) mitochondrial oxidation rates with temperature enhancing both effects. As a result, the thermal sensitivity (Q10) for CI maximal respiration was reduced while that for basal respiration was increased by H-R. H-R reduced both the coupling and phosphorylation efficiencies more profoundly at high temperature suggesting that mitochondria were more resistant to H-R at low temperature. The H-R induced mitochondrial impairments were associated with increased reactive oxygen species (ROS) production and proton leak, dissipation of membrane potential, and loss of structural integrity of the organelles. Overall, our study provides insight into the mechanisms of H-R induced mitochondrial morphofunctional disruption and shows that the moderation of effects of H-R on oxidative phosphorylation by temperature depends on the functional state.

      PubDate: 2016-08-03T10:43:25Z
  • ATP-consuming processes in hepatocytes of river lamprey Lampetra
           fluviatilis on the course of prespawning starvation
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Natalia I. Agalakova, Irina V. Brailovskaya, Svetlana A. Konovalova, Sergei M. Korotkov, Elena A. Lavrova, Anatolii A. Nikiforov
      The work was performed to establish which of the major ATP-consuming processes is the most important for surviving of hepatocytes of female lampreys on the course of prespawning starvation. The requirements of protein synthesis and Na+-K+-ATPase for ATP in the cells were monitored by the changes in mitochondrial membrane potential (MMP) in the presence of corresponding inhibitors from the peak of metabolic depression (January–February) to the time of recovery from it (March–April) and spawning (May). Integrity of lamprey liver cells was estimated by catalytic activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in blood plasma. In January–February, the share of ATP necessary for protein synthesis was 20–22%, whereas before spawning it decreased to 8–11%. Functioning of Na+-K+-pump required 22% of cellular ATP at the peak of metabolic depression, but 38% and 62% of ATP in March–April and May, respectively. Progression of prespawning period was accompanied by 3.75- and 1.6-fold rise of ALT and AST activities in blood plasma, respectively, whereas de Ritis coefficient decreased from 2.51±0.34 to 0.81±0.08, what indicates severe damage of hepatocyte membranes. Thus, the adaptive strategy of lamprey hepatocytes to develop metabolic depression under conditions of energy limitation is the selective production of proteins necessary for spawning, most probably vitellogenins. As spawning approaches, the maintenance of transmembrane ion gradients, membrane potential and cell volume to prevent premature cell death becomes the priority cell function.

      PubDate: 2016-08-03T10:43:25Z
  • Defining the allometric relationship between size and individual fatty
           acid turnover in barramundi Lates calcarifer
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Michael J. Salini, David Poppi, Giovanni M. Turchini, Brett D. Glencross
      An experiment was conducted with barramundi (Asian seabass; Lates calcarifer) to examine the allometric scaling effect of individual fatty acids. Six treatment size classes of fish were deprived of food for 21days (Treatment A, 10.5±0.13g; Treatment B, 19.2±0.11g; Treatment C, 28.3±0.05g; Treatment D, 122.4±0.10g; Treatment E, 217.6±0.36g; Treatment F, 443.7±1.48g; mean±SD) with each treatment comprising of fifteen fish, in triplicate. The assessment of somatic losses of whole-body energy and lipid were consistent with previous studies, validating the methodology to be extended to individual fatty acids. Live-weight (LW) exponent values were determined to be 0.817±0.010 for energy and 0.895±0.007 for lipid. There were significant differences among the fatty acids ranging from 0.687±0.005 for 20:5n-3 (eicosapentaenoic acid) and 0.954±0.008 for 18:1n-9 (oleic acid). The LW exponent values were applied to existing fatty acid intake and deposition data of barramundi fed with either 100% fish oil or 100% poultry oil. From this the maintenance requirement for each fatty acid was determined. The metabolic demands for maintenance and growth were then iteratively determined for fish over a range of size classes. Application of these exponent values to varying levels of fatty acid intake demonstrated that the biggest driver in the utilisation of fatty acids in this species is deposition demand and despite their reputed importance, the long-chain polyunsaturated fatty acids had nominal to no maintenance requirement.

      PubDate: 2016-08-03T10:43:25Z
  • Are mussels able to distinguish underwater sounds' Assessment of the
           reactions of Mytilus galloprovincialis after exposure to lab-generated
           acoustic signals
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Mirella Vazzana, Monica Celi, Giulia Maricchiolo, Lucrezia Genovese, Valentina Corrias, Enza Maria Quinci, Giovanni de Vincenzi, Vincenzo Maccarrone, Gaetano Cammilleri, Salvatore Mazzola, Giuseppa Buscaino, Francesco Filiciotto
      This study examined the effects of lab-generated acoustic signals on the behaviour and biochemistry of Mediterranean mussels (Mytilus galloprovincialis). The experiment was carried out in a tank equipped with a video-recording system using six groups of five mussels exposed to five acoustic treatments (each treatment was replicated three times) for 30min. The acoustic signals, with a maximum sound pressure level of 150dB rms re 1μPa, differed in frequency range as follows: low (0.1–5kHz), mid-low (5–10kHz), mid (10–20kHz), mid-high (20–40kHz) and high (40–60kHz). The exposure to sweeps did not produce any significant changes in the mussels' behaviour. Conversely, the specimens exposed to the low frequency band treatment showed significantly higher values of the following biochemical stress parameters measured in their plasma and tissues: glucose, total proteins, total haemocyte number (THC), heat shock protein 70 (Hsp70) expression, and Acetylcholinesterase (AChE) activity. The responses observed in the mussels exposed to low frequency sweeps enable us to suppose a biological and ecological role for this sound, which contains the main frequencies produced by both shipping traffic and the acoustic emissions of fish.

      PubDate: 2016-08-03T10:43:25Z
  • Effects of random food deprivation and refeeding on energy metabolism,
           behavior and hypothalamic neuropeptide expression in Apodemus chevrieri
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Zhu Wan-long, Wang Zheng-kun
      Maintaining adaptive control of behavior and physiology is the main strategy used by animals in responding to changes of food resources. To investigate the effects of random food deprivation (FD) and refeeding on energy metabolism and behavior in Apodemus chevrieri, we acclimated adult males to FD for 4weeks, then refed them ad libitum for 4weeks (FD-Re group). During the period of FD, animals were fed ad libitum for 4 randomly assigned days each week, and deprived of food the other 3days. A control group was fed ad libitum for 8weeks. At 4 and 8weeks we measured body mass, thermogenesis, serum leptin levels, body composition, gastrointestinal tract morphology, behavior and hypothalamic neuropeptide expression. At 4weeks, food intake, gastrointestinal mass, neuropeptide Y (NPY) and agouti-related protein (AgRP) mRNA expressions increased and thermogenesis, leptin levels, pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) expressions decreased in FD compared with controls. FD also showed more resting behavior and less activity than the controls on ad libitum day. There were no differences between FD-Re and controls at 8weeks, indicating significant plasticity. These results suggested that animals can compensate for unpredictable reduction in food availability by increasing food intake and reducing energy expended through thermogenesis and activity. Leptin levels, NPY, AgRP, POMC, and CART mRNA levels may also regulate energy metabolism. Significant plasticity in energy metabolism and behavior was shown by A. chevrieri over a short timescale, allowing them to adapt to food shortages in nutritionally unpredictable environments.

      PubDate: 2016-08-03T10:43:25Z
  • Calling rate, corticosterone plasma levels and immunocompetence of
           Hypsiboas albopunctatus
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Stefanny Christie Monteiro Titon, Vania Regina de Assis, Braz Titon, Adriana Maria Giorgi Barsotti, Sarah Perry Flanagan, Fernando Ribeiro Gomes
      During the breeding season, male anuran amphibians produce advertisement calls. Androgens play a permissive role in the activation of calling activity, which is often positively correlated to androgen plasma levels and testes mass. Additionally, calling effort is also correlated to corticosterone plasma levels (hereinafter referred to as CORT), which is associated with the mobilization of energy substrates to sustain the high energy flux associated with this activity. However, high CORT also has many immunosuppressive effects and might interfere with reproduction. Consequently, CORT might mediate a compromise between reproductive effort and immunocompetence in anurans. In the present study, we investigated the relationship between calling rate, immunocompetence, and CORT in Hypsiboas albopunctatus, a midsize anuran occurring in South America. To understand these relationships, we conducted focal observations of calling behavior, followed by blood collection for CORT measurements and evaluation of some immune parameters. Our results showed that individuals with larger testes had higher calling rates, and those with higher calling rates showed lower cell-mediated immune response (swelling response to phytohaemagglutinin), although these relationships were not mediated by CORT. Furthermore, males calling early in the evening showed high CORT, and individuals with lower body condition index had higher CORT. We conclude that calling activity shows a cost in terms of cellular immune response in H. albopunctatus, but this compromise does not appear to be mediated by glucocorticoid plasma levels.

      PubDate: 2016-08-03T10:43:25Z
  • Identification of the major proteins present in the seminal plasma of
           European eel, and how hormonal treatment affects their evolution.
           Correlation with sperm quality
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): M. Carmen Vílchez, Davinia Pla, Víctor Gallego, Libia Sanz, Luz Pérez, Juan F. Asturiano, Juan J. Calvete, David S. Peñaranda

      PubDate: 2016-08-03T10:43:25Z
  • Circadian control of prothoracicotropic hormone release in an adult insect
           and the induction of its rhythmicity by light cues
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Michael Cardinal-Aucoin, Colin G.H. Steel
      The insect neuropeptide prothoracicotropic hormone (PTTH) is a critical regulator of larval development. We recently demonstrated that PTTH is also present in adult Rhodnius prolixus and is released by adult brains in vitro with a clear daily rhythm during egg development. Here, we employ a well-established in vitro bioassay, to show that the daily rhythm of PTTH release by brains in vitro is under circadian control since it persists in aperiodic conditions with a free running period of around 24h that is temperature compensated. Prolonged exposure (3weeks) of insects to continuous constant light (LL) completely eliminated PTTH release. Subsequent transfer of such insects from LL to constant darkness (DD) rapidly induced rhythmic PTTH release, indicating that the circadian rhythm of PTTH release is induced by photic cues. Western analysis identified PTTH in the adult hemolymph, suggesting that PTTH acts as a functional neurohormone in the adult insect. Dot blot analysis revealed that PTTH levels in the hemolymph also cycled with a daily rhythm that persisted in DD and was synchronous with the rhythm of PTTH release by brains in vitro. We conclude that the previously documented photosensitive clock in the brain regulates rhythmic PTTH release and thus generates the rhythm seen in the hemolymph. These results emphasize the importance of rhythmic PTTH release in the adult insect and support a role for PTTH in adult physiology and possibly within the adult circadian system.

      PubDate: 2016-08-03T10:43:25Z
  • Responses to thermal and salinity stress in wild and farmed Pacific
           oysters Crassostrea gigas
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): C.-Y. Yang, M.T. Sierp, C.A. Abbott, Yan Li, J.G. Qin
      The Pacific oyster Crassostrea gigas was introduced from Japan to many countries in the world for oyster farming, resulting in the establishment of wild populations in intertidal zones and resource competition with local faunas. This study examined physiological responses of wild oysters and farmed oysters to thermal (15°C, 25°C, 37°C and 44°C) and salinity stress (39, 50 and 60ppt). The wild oysters produced more 72kDa heat shock proteins when the temperature increased from 15°C to 25°C and 37°C and the salinity increased from 39 to 50 and 60ppt. However, the amount of 69kDa heat shock protein was similar between farmed and wild oysters when the temperature increased from 15°C to the sublethal temperature 37°C, but it was lower in wild oysters than in farmed oysters when the temperature increased from 15°C to the lethal temperature 44°C. In the tissues, wild oysters used more glycogen to promote metabolic activities by increasing the level of AEC (adenylate energy charge). The results suggest that farmed oysters might have limited ability to cope with heat stress due to low energy reserve and glycolysis activity for HSP synthesis. This study provides experimental evidence on differential responses between wild and farmed oysters to temperature and salinity changes, leading to a better understanding on the pattern of distribution for invading oyster species in the marine environment and the adaptation of marine invertebrates to the threat of climate change.

      PubDate: 2016-08-03T10:43:25Z
  • Expression and localization of the Xenopus laevis small heat shock
           protein, HSPB6 (HSP20), in A6 kidney epithelial cells
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Imran Khamis, Daniel W. Chan, Cody S. Shirriff, James H. Campbell, John J. Heikkila
      Small heat shock proteins (sHSPs) are molecular chaperones that bind to unfolded protein, inhibit the formation of toxic aggregates and facilitate their refolding and/or degradation. Previously, the only sHSPs that have been studied in detail in the model frog system, Xenopus laevis, were members of the HSP30 family and HSPB1 (HSP27). We now report the analysis of X. laevis HSPB6, an ortholog of mammalian HSPB6. X. laevis HSPB6 cDNA encodes a 168 aa protein that contains an α-crystallin domain, a polar C-terminal extension and some possible phosphorylation sites. X. laevis HSPB6 shares 94% identity with a X. tropicalis HSPB6, 65% with turtle, 59% with humans, 49% with zebrafish and only 50% and 43% with X. laevis HSPB1 and HSP30C, respectively. Phylogenetic analysis revealed that X. laevis HSPB6 grouped more closely with mammalian and reptilian HSPB6s than with fish HSPB6. X. laevis recombinant HSPB6 displayed molecular chaperone properties since it had the ability to inhibit heat-induced aggregation of citrate synthase. Immunoblot analysis determined that HSPB6 was present constitutively in kidney epithelial cells and that heat shock treatment did not upregulate HSPB6 levels. While treatment with the proteasomal inhibitor, MG132, resulted in a 2-fold increase in HSPB6 levels, exposure to cadmium chloride produced a slight increase in HSPB6. These findings were in contrast to HSP70, which was enhanced in response to all three stressors. Finally, immunocytochemical analysis revealed that HSPB6 was present in the cytoplasm in the perinuclear region with some in the nucleus.

      PubDate: 2016-08-03T10:43:25Z
  • Alterations in gene expression during fasting-induced atresia of early
           secondary ovarian follicles of coho salmon, Oncorhynchus kisutch
    • Abstract: Publication date: Available online 16 June 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Yoji Yamamoto, J. Adam Luckenbach, Graham Young, Penny Swanson
      Molecular processes that either regulate ovarian atresia or are consequences of atresia are poorly understood in teleost fishes. We hypothesized that feed restriction that perturbs normal ovarian growth and induces follicular atresia would alter ovarian gene expression patterns. Previtellogenic, two-year old coho salmon (Oncorhynchus kisutch) were subjected to prolonged fasting to induce atresia or maintained on a normal feeding schedule that would promote continued ovarian development. To identify genes that were specifically up- or down-regulated during oocyte growth in healthy, growing fish compared to fasted fish, reciprocal suppression subtractive hybridization (SSH) cDNA libraries were generated using ovaries from fed and fasted animals. Differential expression of genes identified by SSH was confirmed with quantitative PCR. The SSH library representing genes elevated in ovaries of fed fish relative to those of fasted fish contained steroidogenesis-related genes (e.g., hydroxy-delta-5-steroid dehydrogenase), Tgf-beta superfamily members (e.g., anti-Mullerian hormone) and cytoskeletal intermediate filament proteins (e.g., type I keratin s8). Overall, these genes were associated with steroid production, cell proliferation and differentiation, and ovarian epithelialization. The library representing genes elevated in ovaries of fasted fish relative to fed fish contained genes associated with apoptosis (e.g., programmed cell death protein 4), cortical alveoli (e.g., alveolin), the zona pellucida (e.g., zona pellucida protein c), and microtubules (e.g., microtubule associated protein tau). Elevated expression of this suite of genes was likely associated with the initiation of atresia and/or a reduced rate of follicle development in response to fasting. This study revealed ovarian genes involved in normal early secondary oocyte growth and potential early markers of atresia.

      PubDate: 2016-06-18T18:34:03Z
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