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  Subjects -> BIOLOGY (Total: 3149 journals)
    - BIOCHEMISTRY (247 journals)
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    - BIOLOGY (1495 journals)
    - BIOPHYSICS (47 journals)
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BIOCHEMISTRY (247 journals)                  1 2 | Last

Showing 1 - 200 of 247 Journals sorted alphabetically
AAPS PharmSciTech     Hybrid Journal   (Followers: 7)
Acetic Acid Bacteria     Open Access   (Followers: 2)
ACS Central Science     Open Access   (Followers: 9)
ACS Chemical Biology     Full-text available via subscription   (Followers: 293)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 21)
Acta Biochimica Polonica     Open Access  
Acta Crystallographica Section D : Biological Crystallography     Hybrid Journal   (Followers: 10)
Acta Crystallographica Section F: Structural Biology Communications     Hybrid Journal   (Followers: 10)
Advances and Applications in Bioinformatics and Chemistry     Open Access   (Followers: 11)
Advances in Biological Chemistry     Open Access   (Followers: 9)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 7)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 8)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19)
African Journal of Biochemistry Research     Open Access   (Followers: 2)
African Journal of Chemical Education     Open Access   (Followers: 3)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
American Journal of Biochemistry     Open Access   (Followers: 10)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 65)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 17)
American Journal of Polymer Science     Open Access   (Followers: 31)
Amino Acids     Hybrid Journal   (Followers: 8)
Analytical and Bioanalytical Chemistry Research     Open Access   (Followers: 1)
Analytical Biochemistry     Hybrid Journal   (Followers: 176)
Angiogenesis     Hybrid Journal   (Followers: 3)
Annals of Clinical Biochemistry     Hybrid Journal   (Followers: 9)
Annual Review of Biochemistry     Full-text available via subscription   (Followers: 55)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 43)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 17)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 9)
Archives of Biochemistry and Biophysics     Hybrid Journal   (Followers: 21)
Archives of Insect Biochemistry and Physiology     Hybrid Journal   (Followers: 1)
Archives Of Physiology And Biochemistry     Hybrid Journal   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 2)
Bangladesh Journal of Medical Biochemistry     Open Access   (Followers: 3)
BBA Clinical     Open Access  
BBR : Biochemistry and Biotechnology Reports     Open Access   (Followers: 5)
Biocatalysis     Open Access  
Biochemical and Biophysical Research Communications     Hybrid Journal   (Followers: 24)
Biochemical and Molecular Medicine     Full-text available via subscription   (Followers: 5)
Biochemical Compounds     Open Access  
Biochemical Engineering Journal     Hybrid Journal   (Followers: 15)
Biochemical Genetics     Hybrid Journal   (Followers: 3)
Biochemical Journal     Full-text available via subscription   (Followers: 24)
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemical Society Transactions     Full-text available via subscription   (Followers: 4)
Biochemical Systematics and Ecology     Hybrid Journal   (Followers: 3)
Biochemistry     Full-text available via subscription   (Followers: 352)
Biochemistry & Pharmacology : Open Access     Open Access   (Followers: 4)
Biochemistry & Physiology : Open Access     Open Access   (Followers: 1)
Biochemistry (Moscow)     Hybrid Journal   (Followers: 5)
Biochemistry (Moscow) Supplement Series A: Membrane and Cell Biology     Hybrid Journal   (Followers: 4)
Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry     Hybrid Journal   (Followers: 3)
Biochemistry and Biophysics Reports     Open Access  
Biochemistry and Cell Biology     Hybrid Journal   (Followers: 15)
Biochemistry and Molecular Biology Education     Hybrid Journal   (Followers: 6)
Biochemistry and Molecular Biology of Fishes     Full-text available via subscription   (Followers: 1)
Biochemistry Research International     Open Access   (Followers: 6)
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids     Hybrid Journal   (Followers: 7)
Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease     Hybrid Journal   (Followers: 14)
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research     Hybrid Journal   (Followers: 10)
Biochimie     Hybrid Journal   (Followers: 7)
Biochimie Open     Open Access  
Bioconjugate Chemistry     Full-text available via subscription   (Followers: 30)
BioDrugs     Full-text available via subscription   (Followers: 7)
Bioelectrochemistry     Hybrid Journal   (Followers: 2)
Biofarmasi Journal of Natural Product Biochemistry     Open Access  
Biofuels     Hybrid Journal   (Followers: 11)
Biogeochemistry     Hybrid Journal   (Followers: 15)
BioInorganic Reaction Mechanisms     Hybrid Journal   (Followers: 1)
Biokemistri     Open Access  
Biological Chemistry     Partially Free   (Followers: 22)
Biomaterials Research     Open Access   (Followers: 4)
Biomedicines     Open Access   (Followers: 1)
Biomolecular Concepts     Open Access   (Followers: 2)
Bioscience, Biotechnology, and Biochemistry     Hybrid Journal   (Followers: 21)
Biosimilars     Open Access   (Followers: 1)
Biotechnology and Applied Biochemistry     Hybrid Journal   (Followers: 44)
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: 8)
Cell Biochemistry and Biophysics     Hybrid Journal   (Followers: 6)
Cell Biochemistry and Function     Hybrid Journal   (Followers: 7)
Cell Chemical Biology     Hybrid Journal   (Followers: 1)
Cellular Physiology and Biochemistry     Open Access   (Followers: 3)
ChemBioChem     Hybrid Journal   (Followers: 8)
Chemical and Biological Technologies for Agriculture     Open Access  
Chemical Biology & Drug Design     Hybrid Journal   (Followers: 20)
Chemical Engineering Journal     Hybrid Journal   (Followers: 54)
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: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 32)
Chemistry and Ecology     Hybrid Journal  
ChemTexts     Hybrid Journal  
Clinica Chimica Acta     Hybrid Journal   (Followers: 33)
Clinical Biochemist Reviews     Full-text available via subscription   (Followers: 1)
Clinical Biochemistry     Hybrid Journal   (Followers: 18)
Clinical Chemistry     Full-text available via subscription   (Followers: 68)
Clinical Chemistry and Laboratory Medicine     Hybrid Journal   (Followers: 62)
Clinical Lipidology     Open Access   (Followers: 1)
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology     Hybrid Journal   (Followers: 7)
Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 3)
Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology     Hybrid Journal   (Followers: 6)
Comparative Biochemistry and Physiology Part D: Genomics and Proteomics     Hybrid Journal   (Followers: 2)
Comprehensive Biochemistry     Full-text available via subscription   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 11)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Current Biochemical Engineering     Hybrid Journal  
Current Chemical Biology     Hybrid Journal   (Followers: 2)
Current Medicinal Chemistry     Hybrid Journal   (Followers: 15)
Current Opinion in Chemical Biology     Hybrid Journal   (Followers: 31)
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: 59)
FEBS Open Bio     Open Access   (Followers: 3)
Fish Physiology and Biochemistry     Hybrid Journal   (Followers: 3)
Food & Function     Full-text available via subscription   (Followers: 7)
Foundations of Modern Biochemistry     Full-text available via subscription  
Free Radicals and Antioxidants     Full-text available via subscription   (Followers: 4)
Frontiers in Molecular Biosciences     Open Access   (Followers: 2)
Frontiers in Natural Product Chemistry     Hybrid Journal  
Global Biogeochemical Cycles     Full-text available via subscription   (Followers: 18)
Green Chemistry     Full-text available via subscription   (Followers: 10)
Histochemistry and Cell Biology     Hybrid Journal   (Followers: 7)
Indian Journal of Biochemistry and Biophysics (IJBB)     Open Access   (Followers: 2)
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: 6)
International Journal of Biochemistry and Biophysics     Open Access   (Followers: 1)
International Journal of Biological Chemistry     Open Access   (Followers: 2)
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 6)
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: 2)
Journal of Applied Biology & Biotechnology     Open Access   (Followers: 4)
Journal of Applied Biomaterials & Functional Materials     Hybrid Journal  
Journal of Bioactive and Compatible Polymers     Hybrid Journal   (Followers: 3)
Journal of Biochemical and Biophysical Methods     Hybrid Journal   (Followers: 4)
Journal of Biochemistry     Hybrid Journal   (Followers: 42)
Journal of Biochemistry and Molecular Biology Research     Open Access  
Journal of Biological Chemistry     Full-text available via subscription   (Followers: 205)
Journal of Biomaterials Science, Polymer Edition     Hybrid Journal   (Followers: 9)
Journal of Carbohydrate Chemistry     Hybrid Journal   (Followers: 6)
Journal of Cellular Biochemistry     Hybrid Journal   (Followers: 4)
Journal of Chemical Biology     Hybrid Journal   (Followers: 4)
Journal of Chemical Neuroanatomy     Hybrid Journal  
Journal of Clinical Lipidology     Hybrid Journal   (Followers: 2)
Journal of Comparative Physiology B : Biochemical, Systemic, and Environmental Physiology     Hybrid Journal   (Followers: 5)
Journal of Drug Discovery and Therapeutics     Open Access  
Journal of Enzyme Inhibition and Medicinal Chemistry     Open Access   (Followers: 3)
Journal of Evolutionary Biochemistry and Physiology     Hybrid Journal   (Followers: 1)
Journal of Food and Drug Analysis     Open Access  
Journal of Forensic Toxicology and Pharmacology     Hybrid Journal   (Followers: 7)
Journal of Inborn Errors of Metabolism and Screening     Open Access  
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 6)
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: 4)
Journal of Molecular Diagnostics     Hybrid Journal   (Followers: 5)
Journal of Neurochemistry     Hybrid Journal   (Followers: 4)
Journal of Nutritional Biochemistry     Hybrid Journal   (Followers: 7)
Journal of Pediatric Biochemistry     Hybrid Journal   (Followers: 1)
Journal of Peptide Science     Hybrid Journal   (Followers: 21)
Journal of Photochemistry and Photobiology B: Biology     Hybrid Journal   (Followers: 3)
Journal of Physiobiochemical Metabolism     Hybrid Journal   (Followers: 2)
Journal of Physiology and Biochemistry     Hybrid Journal   (Followers: 3)
Journal of Plant Biochemistry and Biotechnology     Hybrid Journal   (Followers: 4)
Journal of Proteins and Proteomics     Open Access  
Journal of Steroid Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 2)
Journal of Virology & Antiviral Research     Hybrid Journal   (Followers: 6)
Journal of Wood Chemistry and Technology     Hybrid Journal   (Followers: 10)
La Rivista Italiana della Medicina di Laboratorio - Italian Journal of Laboratory Medicine     Hybrid Journal  
Lab on a Chip     Full-text available via subscription   (Followers: 37)
Laboratory Techniques in Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 4)
Marine Chemistry     Hybrid Journal   (Followers: 7)
Medical Science and Discovery     Open Access  
Methods in Enzymology     Full-text available via subscription   (Followers: 12)
Molecular and Biochemical Parasitology     Hybrid Journal   (Followers: 2)
Molecular and Cellular Biochemistry     Hybrid Journal   (Followers: 4)
Molecular Aspects of Medicine     Hybrid Journal   (Followers: 3)
Molecular Informatics     Hybrid Journal   (Followers: 5)
Molecular inhibitors in targeted therapy     Open Access  
Moscow University Chemistry Bulletin     Hybrid Journal   (Followers: 1)
Mycologia     Hybrid Journal  
Mycology : An International Journal on Fungal Biology     Hybrid Journal   (Followers: 6)
Natural Products and Bioprospecting     Open Access   (Followers: 2)
Nature Chemical Biology     Full-text available via subscription   (Followers: 74)

        1 2 | Last

Journal Cover
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
Journal Prestige (SJR): 0.836
Citation Impact (citeScore): 2
Number of Followers: 7  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1095-6433
Published by Elsevier Homepage  [3163 journals]
  • Evidence for retinoic acid involvement in the regulation of vitellogenesis
           in the fresh water edible crab, Oziotelphusa senex senex
    • Authors: B.P. Girish; CH. Swetha; M. Srilatha; M. Hemalatha; P. Sreenivasula Reddy
      Pages: 1 - 6
      Abstract: Publication date: August 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 222
      Author(s): B.P. Girish, CH. Swetha, M. Srilatha, M. Hemalatha, P. Sreenivasula Reddy
      The possible involvement of 13-cis retinoic acid (CRA) in the regulation of ovarian development in Oziotelphusa senex senex was investigated. Injection of CRA, into avitellogenic crabs significantly increased ovarian index, oocyte diameter and ovarian vitellogenin levels. Injection of CRA also resulted in a significant increase in the secretory rates of mandibular organs and Y-organs and circulatory levels of the methyl farnesoate and ecdysteroids. Further, administration of CRA into avitellogenic crabs produced higher amounts of Retinoid X Receptor, Ecdysteroid Receptor, E75 and vitellogenin mRNAs in the hepatopancreas. Mandibular organ and Y-organ explants isolated from avitellogenic crabs secreted more of methyl farnesoate and ecdysteroids respectively when incubated with CRA. Taken together, these observations led us to hypothesize that CRA stimulates ecdysteroidogenesis and methyl farnesoate synthesis, up-regulates EcR, RXR and E75 expression in hepatopancreas, which then induces vitellogenin gene expression. Vitellogenin is subsequently taken up from hemolymph by ovaries ensuing in ovarian maturation.

      PubDate: 2018-04-18T10:19:10Z
      DOI: 10.1016/j.cbpa.2018.04.003
      Issue No: Vol. 222 (2018)
       
  • The impact of acute thermal stress on green mussel Perna viridis:
           Oxidative damage and responses
    • Authors: Jing Wang; Bo Dong; Zhen-Xing Yu; Cui-Luan Yao
      Pages: 7 - 15
      Abstract: Publication date: Available online 11 April 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Jing Wang, Bo Dong, Zhen-Xing Yu, Cui-Luan Yao
      Examining the physiological responses of mussels to thermal stress is crucial to evaluate their biogeographic distribution and ability to adapt to a changing climate. In the present study, we investigated the effects of acute cold (8 °C and 15 °C) and heat (35 °C and 42 °C) stress on the mortality rate, reactive oxygen species (ROS) production, malondialdehyde (MDA) content, mitochondrial membrane potential (MMP) and antioxdative responses in the gill tissue of the green mussel species Perna viridis. Our results showed that cold and heat stress induced a temperature-dependent increase in mortality rate. ROS production increased significantly (p < 0.01) after both cold and heat stress. However, the activities of antioxidant enzymes, including SOD, CAT and GSH-Px, were greatly enhanced only after heat stress. In addition, MDA content and MMP increased significantly under both cold and heat stress. The up-regulation of Hsp70 transcripts was only detected after acute stress at 35 °C. However, p38-MAPK phosphorylation levels increased after both cold and heat stress. In addition, a moderate activation of caspase-3 was found after mussels were exposed to 8 °C and 42 °C stress. Our results suggest that both extreme cold and heat stress could induce ROS production in the gill tissue of P. viridis, which might result in lipid peroxidation and mitochondria dysfunction. Antioxidative enzymes and Hsp70 might be important in the heat stress response of animals, whereas p38-MAPK might be crucial in the acute response to both cold and heat stress. However, caspase-3 activation might be very weak under both cold and heat stress.

      PubDate: 2018-04-18T10:19:10Z
      DOI: 10.1016/j.cbpa.2018.04.001
      Issue No: Vol. 222 (2018)
       
  • Expression profile and reproductive regulation of APGWamide in Pacific
           abalone (Haliotis discus hannai)
    • Authors: Kyeong Seop Kim; Tae Ha Kim; Mi Ae Kim; Jung Sick Lee; Young Chang Sohn
      Pages: 26 - 35
      Abstract: Publication date: August 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 222
      Author(s): Kyeong Seop Kim, Tae Ha Kim, Mi Ae Kim, Jung Sick Lee, Young Chang Sohn
      Neuropeptides in the central nervous system regulate reproductive activities in vertebrates. Ala-Pro-Gly-Trp-NH2 (APGWamide), a neuromediator expressed in the neural ganglia of mollusks, controls sexual maturation and reproduction. To clarify the role of APGWamide in sexual behavior regulation and gamete cell maturation in mollusks, we cloned the cDNA of APGWamide precursor ( Hdh - APGWamide ) and examined the spatiotemporal expression of the transcript in the Pacific abalone Haliotis discus hannai. The 222-amino acid sequence of the precursor deduced from the cDNA sequence showed typical features of gastropod APGWamide precursors. Phylogenetic analysis revealed that Hdh-APGWamide is classified with other gastropod APGWamide precursors, which form a separate branch from those of the bivalves. Hdh-APGWamide mRNA was highly expressed in the neural ganglia in both sexes. In females, the three ganglia (pleuro-pedal ganglion, PPG; branchial ganglion, and cerebral ganglion) showed similar expression in immature and mature animals, whereas in males, the level in the PPG only was higher at maturity (P < 0.05). In vivo injection of APGWamide or 5-hydroxytryptamine (10−3 M) increased the frequency of spawning and the number of released sperm cells by mature males (P < 0.05), while concentrations above 10−7 M enhanced germinal vesicle breakdown in fully developed cultured oocytes (P < 0.05). Thus, the phylogenetic branch of the APGWamide precursor gene in Haliotidae was separate from the other branches under the phylum Mollusca, and this gene exhibited ganglion-specific expression, indicating that it may induce final maturation and spawning in both sexes of Haliotis spp.

      PubDate: 2018-04-26T12:03:29Z
      DOI: 10.1016/j.cbpa.2018.04.005
      Issue No: Vol. 222 (2018)
       
  • ZD7288 and mibefradil inhibit the myogenic heartbeat in Daphnia magna
           indicating its dependency on HCN and T-type calcium ion channels
    • Authors: Thomas J. Pirtle; Troy L. Carr; Tanisha Khurana; Grace Meeker
      Pages: 36 - 42
      Abstract: Publication date: August 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 222
      Author(s): Thomas J. Pirtle, Troy L. Carr, Tanisha Khurana, Grace Meeker
      Daphnia magna heartbeat is myogenic—originating within the animal's heart. However, the mechanism for this myogenic automaticity is unknown. The mechanism underlying the automaticity of vertebrate myogenic hearts involves cells (pacemaker cells), which have a distinct set of ion channels that include hyperpolarization activated cyclic nucleotide-gated (HCN) and T-type calcium ion channels. We hypothesized that these ion channels also underlie the automatic myogenic heartbeat of Daphnia magna. The drugs, ZD7288 and mibefradil dihydrochloride, block HCN and T-type calcium ion channels respectively. Application of these drugs, in separate experiments, show that they inhibit the heartbeat of Daphnia magna in a dose-dependent manner. Calculation of the percent difference between the heart rate of pretreatment (before drug application) and heart rate following drug application (post-treatment) allowed us to graph a dose-response curve for both ZD7288 and mibefradil, revealing that ZD7288 produces a greater effect on decreasing heart rate. This indicates the HCN ion channels play a foremost role in generating Daphnia magna heartbeat. Our results show conclusively that HCN and T-type calcium ion channels underlie the automatic myogenic heartbeat in Daphnia magna—and suggest a conserved mechanism for generating myogenic heartbeat within the animal kingdom. Thus, Daphnia magna represents a credible model system for further exploration of cardiac physiology.

      PubDate: 2018-04-26T12:03:29Z
      DOI: 10.1016/j.cbpa.2018.04.009
      Issue No: Vol. 222 (2018)
       
  • Strain-specific effects of crowding on long-term memory formation in
           Lymnaea
    • Authors: Shawn Dodd; Cailin M. Rothwell; Ken Lukowiak
      Pages: 43 - 51
      Abstract: Publication date: August 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 222
      Author(s): Shawn Dodd, Cailin M. Rothwell, Ken Lukowiak
      Crowding of snails is a stress that obstructs long-term memory (LTM) formation following operant conditioning of aerial respiratory behaviour in Lymnaea stagnalis. In previous experiments, snails of the same strain/population were used for both the crowding and the operant conditioning training. However, there are different strains/populations of Lymnaea stagnalis exhibiting different cognitive abilities. We asked whether Lymnaea of one strain/population are able to determine that they are of a different strain/population. We did this by asking if LTM formation would continue to be obstructed if we crowded snails with a different species of pond snail (Helisoma = Planorbella) or with different strains/populations of Lymnaea stagnalis. Using an inbred strain, the W-strain, we crowded the W-strain with seven other Lymnaea strains/populations as well as with Helisoma. The results of a 2-Way ANOVA followed by a Tukey's Post-hoc analysis showed that W-strain snails when crowded with another strain/population of Lymnaea or with Helisoma formed LTM formation. That is, the memory test session statistically met the criteria for LTM formation. Thus, one strain/population of snails determines that another strain/population is different from it. The differentness means that crowding now does not obstruct LTM formation.

      PubDate: 2018-04-26T12:03:29Z
      DOI: 10.1016/j.cbpa.2018.04.010
      Issue No: Vol. 222 (2018)
       
  • Effects of salinity and hypoxia-induced hyperventilation on oxygen
           consumption and cost of osmoregulation in the estuarine red drum
           (Sciaenops ocellatus)
    • Authors: Rasmus Ern; Andrew J. Esbaugh
      Pages: 52 - 59
      Abstract: Publication date: August 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 222
      Author(s): Rasmus Ern, Andrew J. Esbaugh
      Understanding the physiological responses of fishes to salinity changes and aquatic hypoxia is essential for the conservation of marine species. Salinity changes affect the osmotic gradient across the gill epithelium, while hypoxia increases gill ventilation and the flow of water over the gills. Both processes affect the diffusive movement of ions and water across the gill epithelium, and the rate of active ion transport required for maintaining osmotic homeostasis. Consequently, salinity and hypoxia may affect the energetic cost of osmoregulation, and consequently the energy available for other physiological functions such as migration, growth, and reproduction. Historically, studies have assessed the costs of osmoregulation and ventilation in fishes via standard metabolic rate (SMR); however, few studies have used a multi-stressor approach that fully accounts for the osmorespiratory compromise. Here, we determined the combined effects of salinity and hypoxia on SMR, routine metabolic rate (RMR), and plasma ion concentrations in red drum (Sciaenops ocellatus) acclimated to salinities ranging from freshwater to hypersalinity. Surprisingly, there was no significant change in any parameter as a consequence of salinity or hypoxia, including the relatively extreme scenario of combined hypersalinity and hypoxia exposure. We conclude that changes in the osmotic gradient across the gill epithelium and the flow of water over the gills have a negligible effect on the whole animal energy budget of S. ocellatus, suggesting that the cost of osmoregulation is a minor component of basal metabolism regardless of oxygenation status.

      PubDate: 2018-04-26T12:03:29Z
      DOI: 10.1016/j.cbpa.2018.04.013
      Issue No: Vol. 222 (2018)
       
  • The influence of temperature stress on the physiology of the Atlantic
           surfclam, Spisula solidissima
    • Authors: Jesse Hornstein; Emmanuelle Pales Espinosa; Robert M. Cerrato; Kamazima M.M. Lwiza; Bassem Allam
      Pages: 66 - 73
      Abstract: Publication date: Available online 22 April 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Jesse Hornstein, Emmanuelle Pales Espinosa, Robert M. Cerrato, Kamazima M.M. Lwiza, Bassem Allam
      Atlantic surfclam populations have significantly declined in state and federal waters from the south shore of Long Island, New York to the Delmarva Peninsula since the early 2000s. Previous studies have demonstrated that surfclams in this geographic range show signs of physiological stress, suggested to be a result of increasing ocean temperatures. In this study, we examined the effect of 2 temperature regimes (19 °C and 23 °C) on surfclam physiology. These temperatures were chosen because they represent maximal (23 °C) and minimal (19 °C) temperatures prevailing in New York clamming areas during summer. Results demonstrated enhanced energy metabolism and significant reductions in filtration rate, scope for growth, and immune functions in clams exposed to the warmer temperature treatment. Although net energy gains remained positive in both treatments under our experimental conditions, the findings suggest that temperature stress is involved in the recent observations of surfclams in poor condition. The impact of elevated temperatures on phytoplankton quantity/quality and other environmental variables in combination with the direct impact on surfclam filtration and metabolic rates could lead to a negative energy balance. While some uncertainties remain about population-scale impacts of overall warming trends, we fear that future increases in temperature may lead to the collapse of the Atlantic surfclam between New York and Virginia, especially within inshore regions.

      PubDate: 2018-04-26T12:03:29Z
      DOI: 10.1016/j.cbpa.2018.04.011
      Issue No: Vol. 222 (2018)
       
  • Expression profile of glucose transport-related genes under chronic and
           acute exposure to growth hormone in zebrafish
    • Authors: Camila Dalmolin; Daniela Volcan Almeida; Marcio Azevedo Figueiredo; Luis Fernando Marins
      Pages: 1 - 6
      Abstract: Publication date: July 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 221
      Author(s): Camila Dalmolin, Daniela Volcan Almeida, Marcio Azevedo Figueiredo, Luis Fernando Marins
      The brain is a highly demanding organ in terms of energy requirements, and precise regulatory mechanisms must operate to ensure adequate energy delivery to maintain normal neuronal activity. Of the energy-promoting substrates present in the circulation, glucose is preferred by the brain, and as with all other substrates, its utilization depends on the presence of humoral factors such as hormones including growth hormone (GH). Glucose enters the cells though specific transport proteins. Among all transporter families and subtypes described to date, the most studied ones are the glucose transporters (GLUTs). The aim of this study is to determine a possible relationship between GH and GLUTs. Therefore, we evaluated the effect of GH-transgenesis and recombinant GH injections upon GLUT expression in the brain of male zebrafish. Overall, the results demonstrated that increasing the GH concentrations above the normal level, via transgenesis or injection, in the fish may impair energy uptake by the brain. This appeared to occur through downregulation of most of the analyzed GLUTs.

      PubDate: 2018-03-19T06:59:32Z
      DOI: 10.1016/j.cbpa.2018.02.015
      Issue No: Vol. 221 (2018)
       
  • Mitochondrial phenotype during torpor: Modulation of mitochondrial
           
    • Authors: Pablo A. Cortes; Francisco Bozinovic; Pierre U. Blier
      Pages: 7 - 14
      Abstract: Publication date: July 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 221
      Author(s): Pablo A. Cortes, Francisco Bozinovic, Pierre U. Blier
      Mammalian torpor is a phenotype characterized by a controlled decline of metabolic rate, generally followed by a reduction in body temperature. During arousal from torpor, both metabolic rate and body temperature rapidly returns to resting levels. Metabolic rate reduction experienced by torpid animals is triggered by active suppression of mitochondrial respiration, which is rapidly reversed during rewarming process. In this study, we analyzed the changes in the maximal activity of key enzymes related to electron transport system (complexes I, III and IV) in six tissues of torpid, arousing and euthermic Chilean mouse-opossums (Thylamys elegans). We observed higher maximal activities of complexes I and IV during torpor in brain, heart and liver, the most metabolically active organs in mammals. On the contrary, higher enzymatic activities of complexes III were observed during torpor in kidneys and lungs. Moreover, skeletal muscle was the only tissue without significant differences among stages in all complexes evaluated, suggesting no modulation of oxidative capacities of electron transport system components in this thermogenic tissue. In overall, our data suggest that complexes I and IV activity plays a major role in initiation and maintenance of metabolic suppression during torpor in Chilean mouse–opossum, whereas improvement of oxidative capacities in complex III might be critical to sustain metabolic machinery in organs that remains metabolically active during torpor.

      PubDate: 2018-03-19T06:59:32Z
      DOI: 10.1016/j.cbpa.2017.12.014
      Issue No: Vol. 221 (2018)
       
  • Comparison of the organic matrix found in intestinal CaCO3 precipitates
           produced by several marine teleost species
    • Authors: Kevin L. Schauer; Emil A.F. Christensen; Martin Grosell
      Pages: 15 - 23
      Abstract: Publication date: Available online 17 March 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Kevin L. Schauer, Emil A.F. Christensen, Martin Grosell
      Marine bony fish poses the unique ability to hydrate from imbibed seawater. They accomplish this, in part, by the precipitation of inorganic carbonate mineral in their intestine, which lowers luminal osmotic pressure and allows for water uptake. It has recently been described that in the Gulf toadfish (Opsanus beta) this Ca(Mg)CO3 precipitation occurs under the regulation of an organic matrix. To date no investigations have aimed to determine if this phenomenon applies more generally to marine fish. Here, intestinally derived precipitates were collected from gray snapper (Lutjanus griseus), white grunt (Haemulon plumieri), European flounder (Platichthys flesus), as well as Gulf toadfish, and their matrices were extracted. The ability of these matrices to regulate CaCO3 production was determined using an in vitro calcification assay, which revealed that the matrix derived from each of the tested species increased precipitation at low concentrations, while inhibiting it at higher concentrations in full agreement with the earlier studies on toadfish. Matrix extracted from European flounder precipitates was then analyzed by mass spectrometry, leading to the identification of over 50 unique proteins. When the identities of these proteins were compared to previous investigation of toadfish precipitate matrix, nearly 35% were found to overlap between the flounder and toadfish analyses, suggesting conserved mechanisms of precipitation control. The effects of using different sodium hypochlorite (NaOCl) solutions during precipitate purification on the resulting organic matrix are also discussed.

      PubDate: 2018-03-19T06:59:32Z
      DOI: 10.1016/j.cbpa.2018.03.007
      Issue No: Vol. 221 (2018)
       
  • A comparison of hatchery-rearing in exercise to wild animal physiology and
           reflex behavior in Aplysia californica
    • Authors: Lynne A. Fieber; Nicholas S. Kron; Justin B. Greer; Hailey Rooney; Rachel A. Prostko; John D. Stieglitz; Martin Grosell; Phillip R. Gillette
      Pages: 24 - 31
      Abstract: Publication date: Available online 17 March 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Lynne A. Fieber, Nicholas S. Kron, Justin B. Greer, Hailey Rooney, Rachel A. Prostko, John D. Stieglitz, Martin Grosell, Phillip R. Gillette
      Aplysia californica was hatchery-reared in two turbulence protocols intended to imitate the intermittent turbulence of the native habitat and to promote development of the foot muscle from the exercise of adhering to the substrate. Hatchery-reared animals in turbulence regimes were compared to siblings reared in quiet water, and to wild animals, using noninvasive assessments of the development of the foot muscle. The objective was to learn if the turbulence-reared phenotype mimicked laboratory-targeted aspects of the wild phenotype, that is, reflex behavior, swim tunnel performance, and resting oxygen consumption (MO2). No group exhibited different MO2. MO2 values for all of the compared groups of animals followed the power law, with an exponent of 0.69, consistent with this relationship throughout the animal kingdom. Turbulence-induced exercise did not affect the righting reflex or the tail withdrawal reflex, standard behavioral tests that involve the foot muscle, compared to quiet water-reared siblings. Wild individuals had significantly shorter time-to-right than all hatchery reared animals, however, wild animals did not perform better in flume tests. That turbulence-reared hatchery- or wild animals lacked superior in flume performance suggests that this species may shelter from intertidal wave energy to remain near its optimal feeding areas.

      PubDate: 2018-03-19T06:59:32Z
      DOI: 10.1016/j.cbpa.2018.03.006
      Issue No: Vol. 221 (2018)
       
  • Phylogenetic analysis of cnidarian peroxiredoxins and stress-responsive
           expression in the estuarine sea anemone Nematostella vectensis
    • Authors: Rebecca R. Helm; Maria Laura Martín-Díaz; Ann M. Tarrant
      Pages: 32 - 43
      Abstract: Publication date: July 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 221
      Author(s): Rebecca R. Helm, Maria Laura Martín-Díaz, Ann M. Tarrant
      Peroxiredoxins (PRXs) are a family of antioxidant enzymes present in all domains of life. To date, the diversity and function of peroxiredoxins within animals have only been studied in a few model species. Thus, we sought to characterize peroxiredoxin diversity in cnidarians and to gain insight into their function in one cnidarian–the sea anemone Nematostella vectensis. Phylogenetic analysis using all six known PRX subfamilies (PRX1–4, PRX5, PRX6, PRXQ/AHPE1, TPX, BCP-PRXQ) revealed that like bilaterians, cnidarians contain representatives from three subfamilies (PRX1–4, PRX5, PRX6). Within the PRX1–4 subfamily, cnidarian sequences fall into two clades: PRX4, and a cnidarian-specific clade, which we term CNID-PRX. This phylogenetic analysis demonstrates that the three PRX subfamilies present in Bilateria were also present in the last common ancestor of the Cnidaria and Bilateria, and further that diversification of the PRX1–4 subfamily has occurred within the cnidarian lineage. We next examined the impact of decreased salinity, increased temperature, and peroxide exposure on the expression of four prx genes in N. vectensis (cnid-prx, prx4, prx5, and prx6). These genes exhibited unique expression patterns in response to these environmental stressors. Expression of prx4 decreased with initial exposure to elevated temperature, cnid-prx increased with exposure to elevated temperatures as well as with hydrogen peroxide exposure, and expression of all prxs transiently decreased with reduced salinity. Predicted subcellular localization patterns also varied among PRX proteins. Together these results provide evidence that peroxiredoxins in N. vectensis serve distinct physiological roles and lay a groundwork for understanding how peroxiredoxins mediate cnidarian developmental processes and environmental responses.

      PubDate: 2018-04-18T10:19:10Z
      DOI: 10.1016/j.cbpa.2018.03.009
      Issue No: Vol. 221 (2018)
       
  • Differential expression of gonadotropin and estrogen receptors and oocyte
           cytology during follicular maturation associated with egg viability in
           European eel (Anguilla anguilla)
    • Authors: Filipa F.G. da Silva; Helge Tveiten; Gersende Maugars; Anne-Gaëlle Lafont; Sylvie Dufour; Josianne G. Støttrup; Elin Kjørsvik; Jonna Tomkiewicz
      Pages: 44 - 54
      Abstract: Publication date: July 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 221
      Author(s): Filipa F.G. da Silva, Helge Tveiten, Gersende Maugars, Anne-Gaëlle Lafont, Sylvie Dufour, Josianne G. Støttrup, Elin Kjørsvik, Jonna Tomkiewicz
      In captivity, oogenesis and ovarian follicle maturation in European eel can be induced experimentally using hormonal therapy. The follicle's ability to respond effectively to the induction of maturation and ovulation, resulting in viable eggs, depends on the oocyte stage at the time of induction. We hypothesized that variation in the expression of key hormone receptors in the ovary and size of oocyte lipid droplets are associated with changes in oocyte stage. Thus, we induced ovarian follicle maturation using a priming dose of fish pituitary extract followed by the administration of a 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) injection. Females were then strip-spawned, the eggs were fertilized in vitro, incubated and larval survival was recorded at 3 days post hatch (dph). The expression of gonadotropin receptors (fshr, lhcgr1 and lhcgr2) and estrogen receptors (esr1, esr2a, esr2b, gpera and gperb) was quantified and the size of oocyte lipid droplets measured. Larval survival at 3 dph was used to differentiate high- and low-quality egg batches. Results showed significantly higher abundance of lhcgr1 and esr2a at priming for high-quality egg batches whereas fshr and gperb transcripts were significantly higher at DHP injection for low-quality egg batches. Therefore, high levels of lhcgr1 and esr2a may be important for attaining follicular maturational competence, while high fshr and gperb mRNA levels may indicate inadequate maturational competence. Furthermore, lipid droplet size at DHP and in ovulated eggs was significantly smaller in high-quality egg batches than in low-quality, which indicates that droplet size may be a useful marker of follicular maturational stage.

      PubDate: 2018-04-18T10:19:10Z
      DOI: 10.1016/j.cbpa.2018.03.010
      Issue No: Vol. 221 (2018)
       
  • Interactive effects of salinity and temperature acclimation on gill
           morphology and gene expression in threespine stickleback
    • Authors: Taylor C. Gibbons; Tara L. McBryan; Patricia M. Schulte
      Pages: 55 - 62
      Abstract: Publication date: July 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 221
      Author(s): Taylor C. Gibbons, Tara L. McBryan, Patricia M. Schulte
      Colonization of freshwater habitats from marine environments exposes organisms to novel combinations of temperature and salinity, but little is known about physiological responses to the interactive effects of these stressors. Here, we examined the effects of temperature (14 versus 4 °C) and salinity (11 versus 0.3 ppt) on gill gene expression in marine, anadromous, and freshwater populations of threespine stickleback (Gasterosteus aculeatus). Expression of the epithelial calcium channel was not affected by temperature or salinity, but had significantly higher expression in the freshwater ecotype. The combination of low temperature and low salinity had non-additive effects on the expression of the Na+/H+ exchanger. Fish exposed to the combination of low temperature and low salinity had expression levels similar to fish exposed to either factor in isolation. Expression of Na+,K+-ATPase α-subunit was greater in fish exposed to low temperature and low salinity than in fish exposed to the factors separately, and this effect was the most pronounced in the marine ecotype. We also examined the interactive effects of salinity and temperature on gill morphology in the marine ecotype, and observed non-additive effects. Low temperature increased the size of the interlamellar cell mass in fish held at 11 ppt, but not at 0.3 ppt, and the effect of low salinity was in the opposite direction in fish at high and low temperatures. These data demonstrate interactive effects of temperature and salinity and highlight that overwintering in cold freshwater was likely a physiological challenge for marine stickleback as they colonized freshwater following the last glaciation.

      PubDate: 2018-04-18T10:19:10Z
      DOI: 10.1016/j.cbpa.2018.03.013
      Issue No: Vol. 221 (2018)
       
  • Shifts in the relationship between mRNA and protein abundance of gill
           ion-transporters during smolt development and seawater acclimation in
           Atlantic salmon (Salmo salar)
    • Authors: Arne K. Christensen; Amy M. Regish; Stephen D. McCormick
      Pages: 63 - 73
      Abstract: Publication date: July 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 221
      Author(s): Arne K. Christensen, Amy M. Regish, Stephen D. McCormick
      Smolting Atlantic salmon exhibit a seasonal increase in seawater tolerance that is associated with changes in the abundance of major gill ion-transporter transcripts and proteins. In the present study, we investigate how the transcript and protein abundance of specific ion-transporter isoforms relate to each other during smolt development and seawater acclimation, and how each correlates to seawater tolerance. We show that during smolt development both mRNA and protein abundance of gill Na+/K+-ATPase α1a subunit (NKAα1a) decreased but the decrease in the mRNA was five-times greater than that of the protein. Gill NKAα1b mRNA levels increased only slightly (1.5-fold) throughout development whereas protein abundance increased 30-fold at its peak. Gill Na+/K+/2Cl− co-transporter 1 (NKCC1) increased at the mRNA and protein level (5- and 12-fold) in smolts. The abundance of a gill ion-transporter's mRNA and protein changed in the same direction through development and after seawater transfer, but the changes were not always strongly correlated: NKAα1a (r = 0.768), NKAα1b (r = 0.40), and NKCC1 (r = 0.898). The maintenance of plasma chloride concentration correlated most strongly with the abundance of NKAα1a mRNA, and the ratio of NKAα1b to NKAα1a mRNA and protein. Growth performance after seawater transfer correlated most strongly with the abundance of NKAα1b protein and the ratio of NKAα1b to NKAα1a protein. Our results indicate that the abundance of ion-transporter mRNA and protein do not always correlate well and a decrease in the abundance of gill NKAα1a mRNA and increase in NKAα1b protein are strong predictors of seawater tolerance and growth performance after seawater transfer.

      PubDate: 2018-04-18T10:19:10Z
      DOI: 10.1016/j.cbpa.2018.03.020
      Issue No: Vol. 221 (2018)
       
  • Characterization of lipid metabolism genes and the influence of fatty acid
           supplementation in the hepatic lipid metabolism of dusky grouper
           (Epinephelus marginatus)
    • Authors: Bruno C. Araújo; Nicholas M. Wade; Paulo H. de Mello; Jandyr de A. Rodrigues-Filho; Carlos E.O. Garcia; Mariana F. de Campos; Natasha A. Botwright; Diogo T. Hashimoto; Renata G. Moreira
      Pages: 1 - 9
      Abstract: Publication date: Available online 10 February 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Bruno C. Araújo, Nicholas M. Wade, Paulo H. de Mello, Jandyr de A. Rodrigues-Filho, Carlos E.O. Garcia, Mariana F. de Campos, Natasha A. Botwright, Diogo T. Hashimoto, Renata G. Moreira
      Dusky grouper is an important commercial fish species in many countries, but some factors such as overfishing has significantly reduced their natural stocks. Aquaculture emerges as a unique way to conserve this species, but very little biological information is available, limiting the production of this endangered species. To understand and generate more knowledge about this species, liver transcriptome sequencing and de novo assembly was performed for E. marginatus by Next Generation Sequencing (NGS). Sequences obtained were used as a tool to validate the presence of key genes relevant to lipid metabolism, and their expression was quantified by qPCR. Moreover, we investigated the influence of supplementing different dietary fatty acids on hepatic lipid metabolism. The results showed that the different fatty acids added to the diet dramatically changed the gene expression of some key enzymes associated with lipid metabolism as well as hepatic fatty acid profiles. Elongase 5 gene expression was shown to influence intermediate hepatic fatty acid elongation in all experimental groups. Hepatic triglycerides reflected the diet composition more than hepatic phospholipids, and were characterized mainly by the high percentage of 18:3n3 in animals fed with a linseed oil rich diet. Results for the saturated and monounsaturated fatty acids suggest a self-regulatory potential for retention and oxidation processes in liver, since in general the tissues did not directly reflect these fatty acid diet compositions. These results indicated that genes involved in lipid metabolism pathways might be potential biomarkers to assess lipid requirements in the formulated diet for this species.

      PubDate: 2018-02-15T00:35:16Z
      DOI: 10.1016/j.cbpa.2018.01.018
      Issue No: Vol. 219-220 (2018)
       
  • The osmorespiratory compromise in rainbow trout (Oncorhynchus mykiss): The
           effects of fish size, hypoxia, temperature and strenuous exercise on gill
           diffusive water fluxes and sodium net loss rates
    • Authors: John O. Onukwufor; Chris M. Wood
      Pages: 10 - 18
      Abstract: Publication date: Available online 14 February 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): John O. Onukwufor, Chris M. Wood
      In the context of the osmorespiratory compromise, hypoxia and temperature have been little studied relative to exercise, and diffusive water flux rates (as assessed by 3H2O efflux) have received almost no attention. We investigated the effects of fish size, hypoxia, exercise and acute temperature increase on diffusive water flux rates and net sodium loss rates in juvenile rainbow trout. Trout weighing 13–50 g were used to determine the effects of fish size under normoxia. Thereafter 25–50 g trout were selected to assess the effects of different hypoxia levels (3.15, 5.25 and 8.40 KPa), time course of hypoxia (1 h 8.40 KPa, 3 h 8.40 KPa, 1 h 8.40 KPa +1 h normoxic recovery, and 1 h 8.40 KPa + 3 h normoxic recovery), strenuous exercise (5 min) and acute temperature challenge (transfer from 8 °C to 13 °C or to 18 °C). Small fish (13 g) had higher diffusive water flux rates than larger fish, turning over >100% of their fractional body water pool per hour against 34% per hour for 50 g fish. Hypoxic exposure exerted a biphasic effect, increasing the diffusive water flux rate at 8.40 KPa and 5.25 KPa, while returning it to control levels at 3.15 KPa. All the levels of hypoxia increased net Na+ loss. One hour hypoxia (8.40 KPa) increased diffusive water flux rate while prolonged 3 h hypoxia (8.40 KPa), and short or prolonged normoxic recovery returned diffusive water flux rates to control levels. All the treatments over the time course of hypoxia and normoxic recovery increased net Na+ loss rates. Strenuous exercise increased both the diffusive water flux and net Na+ loss rates. Acute temperature rise increased diffusive water flux rates, with Q10 values of 4.03 for 8 to 13 °C and 2.16 for 8 to 18 °C, but the net Na+ loss rate did not change. There was no significant correlation between diffusive water flux rate and net Na+ loss rates at different hypoxia levels, over the course of hypoxia and normoxic recovery, or during acute temperature stress. In contrast, we observed a significant correlation between diffusive water flux and net Na+ loss rates following exercise. Overall, diffusive water flux and sodium loss were regulated differently during acute temperature challenge and hypoxia, while following exercise the two parameters were regulated in a similar fashion.

      PubDate: 2018-02-15T00:35:16Z
      DOI: 10.1016/j.cbpa.2018.02.002
      Issue No: Vol. 219-220 (2018)
       
  • The levels of oxidative stress and antioxidant capacity in hibernating
           Nanorana parkeri
    • Authors: Yonggang Niu; Wangjie Cao; Yaofeng Zhao; Haotian Zhai; Yao Zhao; Xiaolong Tang; Qiang Chen
      Pages: 19 - 27
      Abstract: Publication date: Available online 14 February 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Yonggang Niu, Wangjie Cao, Yaofeng Zhao, Haotian Zhai, Yao Zhao, Xiaolong Tang, Qiang Chen
      The effect of hibernation on oxidative stress and antioxidant defenses was assessed in the frog Nanorana parkeri which inhabits the southern Tibetan Plateau. We compared the indices of oxidative stress (GSSG/GSH), the degree of oxidative damage (content of carbonyl proteins and lipid peroxide products) and the activities of antioxidant enzymes (SOD, CAT, GPx, GST and GR) in liver, brain, heart and muscle of N. parkeri sampled during summer and winter. Obtained results showed that hibernation induced a significant decrease in the levels of GSH in heart, liver, and muscle, while the ratio of GSSG/GSH markedly increased in all tissues except for muscle. Regarding oxidative damage, significant increases in TBARS were observed in all tissues of N. parkeri in the midst of hibernation, and the lipid peroxides levels also clearly elevated in these tissues except the liver. In liver and brain, the levels of carbonyl proteins were significantly higher in winter relative to summer. Additionally, the activity of antioxidant enzymes obviously reduced in the liver of hibernating N. parkeri. The total antioxidant capacity was also significantly lower in all tissues during winter than summer. In conclusion, hibernation in N. parkeri induced oxidative stress which was supported by oxidative damage to lipid and protein with suppression of antioxidant defense.

      PubDate: 2018-02-15T00:35:16Z
      DOI: 10.1016/j.cbpa.2018.02.003
      Issue No: Vol. 219-220 (2018)
       
  • Lipophorin receptor regulates Nilaparvata lugens fecundity by promoting
           lipid accumulation and vitellogenin biosynthesis
    • Authors: Kai Lu; Xia Chen; Yue Li; Wenru Li; Qiang Zhou
      Pages: 28 - 37
      Abstract: Publication date: Available online 21 February 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Kai Lu, Xia Chen, Yue Li, Wenru Li, Qiang Zhou
      Insect lipophorin receptor (LpR) belongs to the low-density lipoprotein receptor (LDLR) superfamily and plays an essential role in fecundity by mediating the incorporation of lipophorin into developing oocytes. Here we report the identification and characterization of a full-length cDNA encoding a putative LpR from the brown planthopper, Nilaparvata lugens. The deduced amino acid sequence of NlLpR possesses the conserved structural motifs of LDLR family members, and displays a high degree of similarity with sequences from other insect LpRs. NlLpR is transcribed throughout oogenesis with its maximum level on day 7 after adult female emergence. NlLpR is highly expressed in the fat body and ovary, with relative low levels in the head, epidermis and midgut. Knockdown of NlLpR using double-stranded RNA (dsRNA) led to decreased triacylglycerol (TAG) content, retarded development of ovaries and decreased fecundity. Further functional analyses revealed that NlLpR works through nutritional signaling pathway-dependent activation of S6 kinase to regulate vitellogenin (Vg) biosynthesis during vitellogenesis and oocyte development. Disrupting of ecdysone receptor (EcR) expression and 20-hydroxyecdysone (20E) topical application demonstrated that NlLpR is regulated by ecdysone at transcript level. These results suggest that LpR is essential for Vg synthesis in the fat body and lipid uptake by developing oocytes, thus playing a critical role in insect reproduction.

      PubDate: 2018-02-26T03:17:50Z
      DOI: 10.1016/j.cbpa.2018.02.008
      Issue No: Vol. 219-220 (2018)
       
  • The physiological stress response of the Atlantic stingray (Hypanus
           sabinus) to aerial exposure
    • Authors: Faith N. Lambert; Jason R. Treberg; W. Gary Anderson; Catherine Brandt; Andrew N. Evans
      Pages: 38 - 43
      Abstract: Publication date: Available online 23 February 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Faith N. Lambert, Jason R. Treberg, W. Gary Anderson, Catherine Brandt, Andrew N. Evans
      Although secondary stress physiology of elasmobranchs is fairly well studied, gaps remain in our understanding of species differences, including stress recovery. We examined the physiological stress response to air exposure in Atlantic stingrays (Hypanus sabinus) using a serial sampling method requiring minimal handling. Many elasmobranch stress studies exclusively quantify glucose, although there is evidence that elasmobranchs are unusually reliant on ketone bodies. Therefore, we also tested the hypothesis that ketone bodies play a significant role in the elasmobranch stress response by examining plasma β-hydroxybutyrate. Plasma osmolality, urea, trimethylamine-N-oxide, and a suite of ions were also measured to characterize departures from homeostasis due to air exposure. H. sabinus were exposed to air for 30 min and serially sampled at 0, 15, and 30 min, as well as 48 h after the stressor to assess the extent of recovery. Blood lactate and acidosis increased significantly during the stressor and returned to basal levels by 48 h. Glucose values were significantly affected, with the highest values observed at 48 h, suggesting that animals were not fully recovered as initially indicated by other metrics. Average plasma β-hydroxybutyrate was unaffected by the stressor. This suggests that ketone bodies may not be a major fuel source used during acute stress, at least in the timeframe examined.

      PubDate: 2018-02-26T03:17:50Z
      DOI: 10.1016/j.cbpa.2018.02.009
      Issue No: Vol. 219-220 (2018)
       
  • Hypoxia inhibits the regulatory volume decrease in red blood cells of
           common frog (Rana temporaria)
    • Authors: Aleksandra Y. Andreyeva; Elizaveta A. Skverchinskaya; Stepan Gambaryan; Aleksander A. Soldatov; Igor V. Mindukshev
      Pages: 44 - 47
      Abstract: Publication date: May 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volumes 219–220
      Author(s): Aleksandra Y. Andreyeva, Elizaveta A. Skverchinskaya, Stepan Gambaryan, Aleksander A. Soldatov, Igor V. Mindukshev
      Red blood cells of vertebrates can restore their cellular volume after hyposmotic swelling. The process strictly depends on oxygen availability in the environment. However, the role of hemoglobin in regulation of cell volume recovery is not clear yet. Little is known about the osmotic reactions and regulatory volume decrease of amphibian red blood cells. We investigated volume recovery process in oxygenated (oxyhemoglobin concentration 97 ± 3% of total hemoglobin) deoxygenated (96 ± 2% of deoxyhemolobin) and oxidized (47 ± 2% of methemoglobin, 41 ± 3% of deoxyhemoglobin) red blood cells of common frog (Rana temporaria) after hyposmotic swelling. Using the low-angle light scattering method we demonstrated the regulatory volume decrease in oxygenated cells and showed that the process was eliminated in hypoxic conditions. Reoxygenation of hypoxic cells restored the regulatory volume decrease. Oxidation of cellular hemoglobin to methemoglobin inhibited the volume recovery response in hyposmotically swollen oxygenated and reoxygenated hypoxic cells.

      PubDate: 2018-03-07T05:27:58Z
      DOI: 10.1016/j.cbpa.2018.02.016
      Issue No: Vol. 219-220 (2018)
       
  • Seasonal variation of pituitary gonadotropin subunit, brain-type aromatase
           and sex steroid receptor mRNAs, and plasma steroids during gametogenesis
           in wild sablefish
    • Authors: José M. Guzmán; J. Adam Luckenbach; Denis A.M. da Silva; Edward S. Hayman; Gina M. Ylitalo; Frederick W. Goetz; Penny Swanson
      Pages: 48 - 57
      Abstract: Publication date: Available online 26 February 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): José M. Guzmán, J. Adam Luckenbach, Denis A.M. da Silva, Edward S. Hayman, Gina M. Ylitalo, Frederick W. Goetz, Penny Swanson
      Pituitary-hormone signaling plays critical roles in the onset and progression of gametogenesis in vertebrates. This study characterized expression patterns of pituitary gonadotropin beta-subunits (fshb and lhb), brain-type aromatase (cyp19a1b), androgen (ar1, ar2) and estrogen receptors (esr1, esr2a, esr2b), and changes in plasma steroid levels by liquid chromatography/tandem mass spectrometry in wild sablefish (Anoplopoma fimbria, order Scorpaeniformes) during a complete reproductive cycle. Transcripts for fshb increased during early gametogenesis and peaked in late vitellogenic females and late recrudescent males, while expression of lhb reached maximum levels in periovulatory and spermiating fish. Pituitary levels of cyp19a1b and ar1 were strongly correlated with those of lhb in females and males, increasing during gametogenesis and reaching maximum levels prior to spawning. By contrast, expression of ar2, and the three estrogen receptors differed between female and male sablefish. 17β-estradiol (E2) was the dominant steroid in females during vitellogenesis, while a range of at least 6 steroids (11β-hydroxyandrostenedione, testosterone [T], E2, 11-ketotestosterone, 11-deoxycortisol, and 17α,20β,21-trihydroxyprogesterone) were detected at similar levels in males during testicular development. Prior to spawning, a marked increase in 4-androstenedione, T, 11KT and E2 was found in both periovulatory females and spermiating males. In conclusion, the concomitant changes in plasma androgen levels and pituitary ar1 expression during gametogenesis suggest a specific role for androgens in pituitary hormone regulation of reproduction in sablefish. Further, our data highlight the importance of E2 during final stages of maturation in this species, which may regulate the transcription of pituitary lhb in a paracrine fashion.

      PubDate: 2018-03-07T05:27:58Z
      DOI: 10.1016/j.cbpa.2018.02.010
      Issue No: Vol. 219-220 (2018)
       
  • Effect of incubation temperature on neuropeptide Y and neuropeptide Y
           receptors in turkey and chicken satellite cells
    • Authors: Daniel L. Clark; Janet L. McCormick; Sandra G. Velleman
      Pages: 58 - 66
      Abstract: Publication date: Available online 2 March 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Daniel L. Clark, Janet L. McCormick, Sandra G. Velleman
      Neuropeptide Y (NPY) is an appetite stimulating peptide released from the central nervous system and impacts the function of many different cell types. A recent transcriptome study showed that NPY expression was altered when turkey breast muscle satellite cells were incubated at low or high temperatures, suggesting NPY may mediate temperature effects on satellite cells. However, to date minimal information exists describing the expression and function of NPY in satellite cells. The objective of this study was to determine how temperature impacts NPY and NPY receptor gene expression in satellite cells isolated from turkeys and chickens with differing genetic lineages. Two broiler and two turkey breast muscle satellite cell lines were incubated at 35, 38 or 41 °C during proliferation and differentiation. In both turkey lines, NPY, and receptors NPY2R and NPY5R expression increased at elevated temperatures after 72 h of proliferation. During differentiation NPY and NPY5R expression increased in both turkey lines with higher temperatures, whereas NPY2R was minimally affected by temperature. In contrast, in both chicken cell lines there were few significant differences for NPY and NPY receptor expression across temperature during proliferation. During differentiation, the temperature effect was different in the two chicken cell lines. In the BPM8 chicken line, there were few differences in NPY and NPY receptors across temperature; whereas elevated temperatures increased NPY, NPY2R, and NPY5R expression in the 708 line. The differences between turkey and chicken lines suggest NPY has species specific satellite cell functions in response to heat stress.

      PubDate: 2018-03-07T05:27:58Z
      DOI: 10.1016/j.cbpa.2018.02.014
      Issue No: Vol. 219-220 (2018)
       
  • Corrigendum to “Respiration-based monitoring of metabolic rate following
           cold-exposure in two invasive Anoplophora species depending on acclimation
           regime” [Comp. Biochem. Physiol. A Vol. 216 (2018) 20-27]
    • Authors: M. Javal; A. Roques; G. Roux; M. Laparie
      First page: 67
      Abstract: Publication date: May 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volumes 219–220
      Author(s): M. Javal, A. Roques, G. Roux, M. Laparie


      PubDate: 2018-04-18T10:19:10Z
      DOI: 10.1016/j.cbpa.2018.03.005
      Issue No: Vol. 219-220 (2018)
       
  • Regulation of NlE74A on vitellogenin might be mediated by angiotensin
           converting enzyme through a fecundity-related SNP in the brown
           planthopper, Nilaparvata lugens
    • Abstract: Publication date: Available online 20 June 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Zhongxiang Sun, Qi Shi, Cuicui Xu, Rumeng Wang, Huanhuan Wang, Yuanyuan Song, Rensen Zeng
      The major yolk protein precursors (YPP) gene, vitellogenin (Vg), usually considered as a reproductive indicator and molecular marker for evaluating insect fecundity, is controlled by insect hormone (mainly ecdysteroids and juvenile hormone), transcription factors and many other fecundity-related genes. To better understand the underlying molecular regulation mechanisms of the NlVg in the brown planthopper Nilaparvata lugens (N. lugens), the correlation between one early ecdysone response gene E74 and one important fecundity-related gene angiotensin converting enzyme (ACE) on the regulation of Vg gene expression, was investigated. We first showed that the mRNA expression level of NlACE were significantly higher in a high-fecundity population (HFP) than a low-fecundity population (LFP) at different development stages, and knockdown of NlACE expression by RNA interference (RNAi) results in a reduced level of NlVg expression and N. lugens fecundity. Subsequently, we analyzed the promoter of NlACE and found an E74A binding site, which was also differentially expressed in HFP and LFP. Then a gene putatively encoding E74A, namely NlE74A, predominant in the ovary and fat body was cloned and characterized. Furthermore, the developmental profile during female adult and the tissue-specific expression pattern of NlACE and NlE74A were similar to the expression pattern of NlVg gene, implying that both NlACE and NlE74A may be involved in regulating the expression of NlVg. Finally, after injecting the dsRNA of NlE74A, the NlACE expression levels were significantly reduced simultaneously at 24 h and 48 h post-injection, and the NlVg expression level was significant reduced at 24 h post-injection and the downswing was more significant at 48 h post-injection. These results imply that regulation of NlE74A on NlVg transcription might be mediated by NlACE through the E74 binding site at the NlACE promoter region in N. lugens.

      PubDate: 2018-06-22T07:49:13Z
       
  • Short- and long-term salinity challenge, Osmoregulatory ability, and (Na+,
           K+)-ATPase KINETICS AND α-SUBUNIT mRNA expression in the gills of the
           thinstripe hermit CRAB Clibanarius symmetricus
    • Abstract: Publication date: Available online 19 June 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Rogério O. Faleiros, Daniela P. Garçon, Malson N. Lucena, John C. McNamara, Francisco A. Leone
      The evolutionary history of the Crustacea reveals ample adaptive radiation and the subsequent occupation of many osmotic niches resulting from physiological plasticity in their osmoregulatory mechanisms. We evaluate osmoregulatory ability in the intertidal, thinstripe hermit crab Clibanarius symmetricus after short-term exposure (6 h) or long-term acclimation (10 days) to a wide salinity range, also analyzing kinetic behavior and α-subunit mRNA expression of the gill (Na+, K+)-ATPase. The crab strongly hyper-regulates its hemolymph at 5 and 15‰S (Salinity, g L−1) but weakly hyper-regulates up to ≈27‰S. After 6 h exposure to 35‰S and 45‰S, C. symmetricus slightly hypo-regulates its hemolymph, becoming isosmotic after 10 days acclimation to these salinities. (Na+, K+)-ATPase specific activity decreases with increasing salinity for both exposure periods, reflecting physiological adjustment to isosmoticity. At low salinities, the gill enzyme exhibits a single, low affinity ATP binding site. However, at elevated salinities, a second, high affinity, ATP binding site appears, independently of exposure time. (Na+, K+)-ATPase α-subunit mRNA expression increases only after 10 days acclimation to 5‰S. Our findings suggest that hemolymph hyper-regulation is effected by alterations in enzyme activity during short-term exposure, but is sustained by increased mRNA expression during long-term acclimation. The decrease in gill (Na+, K+)-ATPase activity seen as a consequence of increasing salinity appears to underlie biochemical adjustments to hemolymph isosmoticity as hypo-regulatory ability diminishes.

      PubDate: 2018-06-22T07:49:13Z
       
  • RANKL, Ephrin-Eph and Wnt10b are key intercellular communication molecules
           regulating bone remodeling in autologous transplanted goldfish scales
    • Abstract: Publication date: Available online 15 June 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Yuya Tazaki, Kayo Sugitani, Kazuhiro Ogai, Isao Kobayashi, Haruki Kawasaki, Takafumi Aoyama, Nobuo Suzuki, Yoshiaki Tabuchi, Atsuhiko Hattori, Kei-ichiro Kitamura
      This study aimed to investigate the precise data of gene expression, functions, and chronological relationships amongst communication molecules involved in the bone remodeling process with an in vivo model using autologous transplanted scales of goldfish. Autotransplantation of methanol-fixed cell-free scales triggers scale resorption and regeneration, as well as helps elucidate the process of bone remodeling. We investigated osteoclastic markers, osteoblastic markers, and gene expressions of communicating molecules (RANKL, ephrinB2, EphB4, EphA4, Wnt10b) by qPCR, in situ hybridization for Wnt10b, and immunohistochemistry for EphrinB2 and EphA4 proteins to elucidate the bone remodeling process. Furthermore, functional inhibition experiments for the signaling of ephrinB2/Eph, ephrin/EphA4, and Wnt10b using specific antibodies, revealed that these proteins are involved in key signaling pathways promoting normal bone remodeling. Our data suggests that the remodeling process comprises of two successive phases. In the first absorption phase, differentiation of osteoclast progenitors by RANKL is followed by the bone absorption by mature, active osteoclasts, with the simultaneous induction of osteoblast progenitors by multinucleated osteoclast-derived Wnt10b, and proliferation of osteoblast precursors by ehprinB2/EphB4 signaling. Subsequently, during the second formation phase, termination of bone resorption by synergistic cooperation occurs, with downregulation of RANKL expression in activated osteoblasts and Ephrin/EphA4-mediated mutual inhibition between neighboring multinucleated osteoclasts, along with simultaneous activation of osteoblasts via forward and reverse EphrinB2/EphB4 signaling between neighboring osteoblasts. In addition, the present study shows that autologous transplantation of methanol-fixed cell-free scale is an ideal in vivo model to study bone remodeling.

      PubDate: 2018-06-19T06:58:27Z
       
  • Assessing the role of the acid-sensing ion channel asic4b in sodium uptake
           by larval zebrafish
    • Abstract: Publication date: Available online 15 June 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Alex M. Zimmer, Agnieszka K. Dymowska, Yusuke Kumai, Greg G. Goss, Steve F. Perry, Raymond W.M. Kwong
      Na+ uptake in larval zebrafish (Danio rerio) is coordinated by three mechanisms: Na+/H+-exchanger 3b (NHE3b) expressed in H+-ATPase-rich (HR) cells, an unidentified Na+ channel coupled to electrogenic H+-ATPase expressed in HR cells, and Na+-Cl−-cotransporter (NCC) expressed in NCC cells. Recently, acid-sensing ion channels (ASICs) were proposed to be the putative Na+ channel involved in H+-ATPase-mediated Na+ uptake in adult zebrafish and rainbow trout. In the present study, we hypothesized that ASICs also play this role in Na+ uptake in larval zebrafish. In support of this hypothesis, immunohistochemical analyses revealed that ASIC4b was expressed in HR cells on the yolk sac skin at 4 days post-fertilization (dpf). However, neither treatment with the ASIC-specific blocker 4,6-diamidino-2-phenylindole (DAPI) nor morpholino knockdown of ASIC4b reduced Na+ uptake in circumneutral conditions at 4 dpf. However, because ASIC4b knockdown led to significant increases in the mRNA expression of nhe3b and ncc and a significant increase in HR cell density, it is possible that Na+ influx was sustained by increased participation of non-ASIC4b pathways. Moreover, when fish were reared in acidic water (pH = 4), ASIC4b knockdown led to a stimulation of Na+ uptake at 3 and 4 dpf, results which also were inconsistent with an essential role for ASIC-mediated Na+ uptake, even under conditions known to constrain Na+ uptake via NHE3b. Thus, while ASIC4b clearly is expressed in HR cells, the current functional experiments cannot confirm its involvement in Na+ uptake in larval zebrafish.

      PubDate: 2018-06-19T06:58:27Z
       
  • Uncoupling protein 1 in snakehead (Channa argus): Cloning, tissue
           distribution, and its expression in response to fasting and refeeding
    • Abstract: Publication date: Available online 8 June 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Chuan-Jie Qin, Zheng-Yong Wen, Jun Wang, Yang He, Deng-Yue Yuan, Rui Li
      In mammals, uncoupling protein 1 (UCP1) is well known for its thermogenic role in brown adipose tissue (BAT). However, the UCP1 physiological roles are still unclear in fish, although several teleost ucp1 genes have been identified. The aim of this study is to investigate the potential roles of fish UCP1 involved in food intake regulation and energy homeostasis. We herein report on the molecular cloning, tissue distribution and the effect of fasting and refeeding on the expression of ucp1 in Channa argus. UCP1 consisted of a 921 bp open reading frame predicted to encode 306 amino acids. Sequence analysis revealed that snakehead UCP1 was highly conserved (>80%) with teleost UCP1, but shared a lower identity (60–72%) with mammals. Phylogenetic analysis supported that snakehead UCP1 was closely related to piscine UCP1. In addition, ucp1 was found to extensively expressed in all detected tissues, with the highest level in liver. Futhermore, the hepatic ucp1 was found to significantly increased after short-term and long-term food deprivation, and dramatically increased following refeeding. These findings suggested that snakehead UCP1 might play important roles in food intake regulation and fatty acid metabolism in snakehead fish, and it could be as a potential target locus to improve commercial production of this kind of fish.

      PubDate: 2018-06-10T06:12:51Z
       
  • The rostral medulla of bullfrog tadpoles contains critical lung
           rhythmogenic and chemosensitive regions across metamorphosis
    • Abstract: Publication date: Available online 8 June 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Mitchell D. Reed, Kimberly E. Iceman, Michael B. Harris, Barbara E. Taylor
      The development of amphibian breathing provides insight into vertebrate respiratory control mechanisms. Neural oscillators in the rostral and caudal medulla drive ventilation in amphibians, and previous reports describe ventilatory oscillators and CO2 sensitive regions arise during different stages of amphibian metamorphosis. However, inconsistent findings have been enigmatic, and make comparisons to potential mammalian counterparts challenging. In the current study we assessed amphibian central CO2 responsiveness and respiratory rhythm generation during two different developmental stages. Whole-nerve recordings of respiratory burst activity in cranial and spinal nerves were made from intact or transected brainstems isolated from tadpoles during early or late stages of metamorphosis. Brainstems were transected at the level of the trigeminal nerve, removing rostral structures including the nucleus isthmi, midbrain, and locus coeruleus, or transected at the level of the glossopharyngeal nerve, removing the putative buccal oscillator and caudal medulla. Removal of caudal structures stimulated the frequency of lung ventilatory bursts and revealed a hypercapnic response in normally unresponsive preparations derived from early stage tadpoles. In preparations derived from late stage tadpoles, removal of rostral or caudal structures reduced lung burst frequency, while CO2 responsiveness was retained. Our results illustrate that structures within the rostral medulla are capable of sensing CO2 throughout metamorphic development. Similarly, the region controlling lung ventilation appears to be contained in the rostral medulla throughout metamorphosis. This work offers insight into the consistency of rhythmic respiratory and chemosensitive capacities during metamorphosis.

      PubDate: 2018-06-10T06:12:51Z
       
  • Comparing Enchytraeus albidus populations from contrasting climatic
           
    • Abstract: Publication date: Available online 6 June 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Anamarija Žagar, Martin Holmstrup, Tatjana Simčič, Barabara Debeljak, Stine Slotsbo
      Basal metabolic activity and freezing of body fluids create reactive oxygen species (ROS) in freeze-tolerant organisms. These sources of ROS can have an additive negative effect via oxidative stress. In cells, antioxidant systems are responsible for removing ROS in order to avoid damage due to oxidative stress. Relatively little is known about the importance of metabolic rate for the survival of freezing, despite a good understanding of several cold tolerance related physiological mechanisms. We hypothesized that low basal metabolism would be selected for in freeze-tolerant organisms where winter survival is important for fitness for two reasons. First, avoidance of the additive effect of ROS production from metabolism and freezing, and second, as an energy-saving mechanism under extended periods of freezing where the animal is metabolically active, but unable to feed. We used the terrestrial oligochaete, Enchytraeus albidus, which is widely distributed from Spain to the high Arctic and compared eight populations originating across a broad geographical and climatic gradient after they had been cold acclimated at 5 °C in a common garden experiment. Cold tolerance (lower lethal temperature: LT50) and the potential metabolic activity (PMA, an estimator of the maximal enzymatic potential of the mitochondrial respiration chain) of eight populations were positively correlated amongst each other and correlated negatively with latitude and positively with average yearly temperature and the average temperature of the coldest month. These results indicate that low PMA in cold tolerant populations is important for survival in extremely cold environments.

      PubDate: 2018-06-07T05:58:42Z
       
  • Response of the insulin-like growth factor-1 (Igf1) system to nutritional
           
    • Abstract: Publication date: Available online 5 June 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Nicole L. Hack, Jackson S. Strobel, Meredith L. Journey, Brian R. Beckman, Sean C. Lema
      Growth performance in vertebrates is regulated by environmental factors including the quality and quantity of food, which influence growth via endocrine pathways such as the growth hormone (GH)/insulin-like growth factor somatotropic axis. In several teleost fishes, circulating concentrations of insulin-like growth factor-1 (Igf1) correlate positively with growth rate, and it has been proposed that plasma Igf1 levels may serve as an indicator of growth variation for fisheries and aquaculture applications. This study tested whether plasma Igf1 concentrations might serve as an indicator of somatic growth in olive rockfish (Sebastes serranoides), one species among dozens of rockfishes important to commercial and recreational fisheries in the Northern Pacific Ocean. Juvenile olive rockfish were reared under food ration treatments of 1% or 4% wet mass per d for 98 d to experimentally generate variation in growth. Juvenile rockfish in the 4% ration grew 60% more quickly in mass and 22% faster in length than fish in the 1% ration. Plasma Igf1 levels were elevated in rockfish under the 4% ration, and individual Igf1 levels correlated positively with growth rate, as well as with individual variation in hepatic igf1 mRNA levels. Transcripts encoding the Igf binding proteins (Igfbps) igfbp1a and igfbp1b were also at higher abundance in the liver of rockfish in the 1% ration treatment, while mRNAs for igfbp5a and igfbp5b were elevated in the skeletal muscle of 4% ration fish. These findings support the use of plasma Igf1 as a physiological index of growth rate variation in rockfish.

      PubDate: 2018-06-07T05:58:42Z
       
  • The effects of warm temperature acclimation on constitutive stress,
           immunity, and metabolism in white sturgeon (Acipenser transmontanus) of
           different ploidies
    • Abstract: Publication date: Available online 2 June 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Michaiah J. Leal, Brigitte E. Clark, Joel Van Eenennaam, Andrea D. Schreier, Anne E. Todgham
      Previous studies suggest fish with additional copies of their genome (polyploids) underperform in suboptimal conditions and may be more susceptible to stress and disease. The objective of this study was to determine the role ploidy plays in the physiological response of white sturgeon to chronically elevated water temperatures. White sturgeon of two ploidies (8 N and 10 N) were acclimated to ambient (18 °C) and warm (22 °C) water. Bioindices of stress (plasma cortisol, glucose and lactate, total erythrocyte count, hematocrit, hemoglobin, mean erythrocyte volume, mean erythrocyte hemoglobin, and mean erythrocyte hemoglobin concentration), immunity (respiratory burst, plasma lysozyme, and total leukocyte count), and cellular metabolic capacity (lactate dehydrogenase and citrate synthase activity) were measured before and after a 6-week acclimation period. Both ploidies appear comparable in their constitutive immune and stress parameters and respond similarly to warming. Hematological indices suggest 8 N and 10 N sturgeon are similar in oxygen carrying capacity; however, differences in enzyme activity between ploidies indicate that 10 N sturgeon may have a lower cellular aerobic capacity. Our results have implications for the screening and management of ploidy on white sturgeon farms and hatcheries, as the differences between ploidies may affect 10 N sturgeon performance at elevated water temperatures. Further research is needed to elucidate the differences in inducible stress and immune responses and metabolism of white sturgeon of different ploidies.

      PubDate: 2018-06-04T05:50:38Z
       
  • Does hypoxia or different rates of re-oxygenation after hypoxia induce an
           oxidative stress response in Cyphocharax abramoides (Kner 1858), a
           Characid fish of the Rio Negro'
    • Abstract: Publication date: Available online 1 June 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Ora E. Johannsson, Marina Giacomin, Helen Sadauskas-Henrique, Derek Campos, Susana Braz-Mota, Waldir Heinrichs-Caldas, Ramon Baptista, Chris M. Wood, Vera Maria F. Almeida-Val, Adalberto L. Val
      We examined whether oxidative damage and antioxidant responses are more likely to occur during hypoxia or re-oxygenation in hypoxia-tolerant fish, and whether there is an influence of the rate of re-oxygenation. An hypoxia/re-oxygenation experiment using wild-caught Cyphocharax abramoides (Rio Negro, Brazil), was designed to answer these questions. Lipid peroxidation (MDA), a measure of oxidative damage, and antioxidant activities superoxide dismutase (SOD), glutathione peroxidase (GPx), antioxidant capacity against peroxyl radicals (ACAP), were measured in brain, gill and liver tissues after normoxia, 3-h hypoxia (2.7 kPa), and 3-h hypoxia followed by 1-h or 3-h re-oxygenation, implemented either immediately or slowly (3.0 kPa·h−1). Critical oxygen tension of routine oxygen consumption rate (Pcrit) (4.1 kPa) and the PO2 at loss of equilibrium (LOE) (1.7 kPa) were determined to set the experimental hypoxia exposure. The Regulation Index, a measure of oxyregulation with declining PO2, was 0.32. Oxidative damage occurred during hypoxia: no additional damage was observed during re-oxygenation. Tissues responded differentially. GPx and MDA rose in the brain and gills, and SOD (and likely GPx) in the liver during hypoxia. Antioxidants increased further at LOE. Rate of oxygen increase during re-oxygenation did not affect antioxidant responses. In brain and gills, GPx and MDA decreased or recovered after 1-h re-oxygenation. In liver, SOD remained high and GPx increased. In summary, C. abramoides incurred oxidative damage during hypoxic exposure with no additional damage inflicted during re-oxygenation: the rate of re-oxygenation was inconsequential. Literature data supports conclusion of greater damage during hypoxia than during re-oxygenation in hypoxia-tolerant fish.

      PubDate: 2018-06-04T05:50:38Z
       
  • The effects of fasting and appetite regulators on catecholamine and
           serotonin synthesis pathways in goldfish (Carassius auratus)
    • Abstract: Publication date: September 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 223
      Author(s): Stephanie Mandic, Hélène Volkoff
      Monoamine neurotransmitters such as catecholamines [dopamine (DA), norepinephrine (NE) and epinephrine (E)] and serotonin have been shown to influence feeding in vertebrates. In order to better understand the role of monoamine neurotransmitters in the regulation of feeding in fish, we examined the effects of fasting on the brain and intestine gene expression of enzymes involved in their synthesis pathways (SPR: sepiapterin reductase; DHPR: dihydropteridine reductase; TH: tyrosine hydroxylase; TPH: tryptophan hydroxylase; AADC: aromatic l-amino acid decarboxylase; DBH: dopamine β-hydroxylase) in goldfish. In order possible interactions between the monoaminergic pathways and appetite-regulating hormones, we examined the effects of intraperitoneal injections of orexin, CCK and irisin on the brain and intestine gene expression of these enzymes. Fasting increased the expressions of SPR, TH, DBH, TPH1 and DHPR in the brain but did not affect the intestinal expressions of any of the enzymes examined, suggesting that nutritional status might affect the synthesis of monoamines in the central nervous system. CCK injections decreased feeding and increased SPR, TH, and TPH expressions in both brain and intestine. Orexin injections increased feeding and SPR and AADC expressions in the brain but did not affect the expressions of any of the enzymes in the intestine. Irisin injections decreased feeding and increased TPH2 and AADC brain expressions and TH and SPR intestinal expressions, and decreased TPH1 brain expression and AADC intestinal expression. Our results suggest that feeding/fasting and appetite-regulating hormones modulate in part the catecholamine and serotonin synthesis pathways in goldfish.

      PubDate: 2018-05-29T04:34:03Z
       
  • Effect of high temperature stress on heat shock protein expression and
           antioxidant enzyme activity of two morphs of the mud crab Scylla
           paramamosain
    • Abstract: Publication date: September 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 223
      Author(s): Zi-Ming Liu, Xian-Long Zhu, Jun Lu, Wan-Jun Cai, Ya-Ping Ye, Yao-Ping Lv
      The present study aimed to investigate the effect rapid temperature change from moderate temperature to high temperatures on heat shock protein (HSP) expression and antioxidant enzyme activities in mud crabs. Two mud crabs, one with one spine on the outer margin of the carpus of cheliped (Sp1) and another with two spines (Sp2), were acclimated at 25 °C and then transferred to a 33 °C environment, and HSP expression and antioxidant enzyme activity were assessed. HSP70 and HSP60 were markedly up-regulated in the gills and hepatopancreas of Sp1 and Sp2 after exposure to 35 °C. Exposure to 35 °C also significantly increased superoxide dismutase and catalase activity in the gills of Sp1 and Sp2, with transient changes in hepatopancreas. Apart from changes in antioxidant enzyme activities, HSPs were highly up-regulated after exposure to 37 °C, especially for HSP70. Gill HSP70 expression in Sp2 was 6.1 folds that of the control after 24 h of exposure to 37 °C, and 9.2 folds that of Sp1. Moreover, exposure to 37 °C further up-regulated HSP70 in the hepatopancreas of Sp1, compared to that in Sp2. Hence, HSPs play important roles in thermotolerance in S. paramamosain and Sp1 might have a stronger tolerance to hyperthermal stress than Sp2.

      PubDate: 2018-05-29T04:34:03Z
       
  • The behavioral energetics of New Zealand's bats: Daily torpor and
           hibernation, a continuum
    • Abstract: Publication date: September 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 223
      Author(s): Brian K. McNab, Colin O'Donnell
      We examine the impact of behavior on the short-term energy expenditures of the only terrestrial mammals endemic to New Zealand, two bats, the long-tailed (Chalinolobus tuberculatus, family Vespertilionidae), and the lesser short-tailed (Mystacina tuberculata, family Mystacinidae). Vespertilionidae has a world-wide distribution. Mystacinidae is restricted to New Zealand, although related to five neotropical families and one in Madagascar reflecting a shared Gondwanan origin of their Noctilionoidea superfamily. Both species have highly variable body temperatures and rates of metabolism. They feed on flying insects, which requires them to be torpid in shelters during cold, wet periods. In dry weather Mystacina is active in winter at ambient temperatures as low as −1.0 °C, foraging for terrestrial invertebrates in leaf litter, even in the presence of snow, and consuming fruit, nectar, and pollen from endemic plants that bloom in winter. The behavior of Mystacina expands its presence in a cool, wet, temperate forest in a manner unlike any other bat, another example of the distinctive characteristics of the endemic New Zealand fauna. The use of torpor generally depends on a series of factors, including body mass, ambient temperature, latitude, reproductive cycle, sociality, and fat deposits. These factors result in a diversity of responses that range along a continuum from short-term torpor to hibernation.

      PubDate: 2018-05-29T04:34:03Z
       
  • Characterization of LPXRFa receptor in the half-smooth tongue sole
           (Cynoglossus semilaevis): Molecular cloning, expression profiles, and
           differential activation of signaling pathways by LPXRFa peptides
    • Abstract: Publication date: September 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 223
      Author(s): Bin Wang, Guokun Yang, Quan Liu, Jingkai Qin, Yongjiang Xu, Wensheng Li, Xuezhou Liu, Bao Shi
      Gonadotropin-inhibitory hormone (GnIH), a novel hypothalamic neuropeptide, serves as a key player in the regulation of reproduction across vertebrates, acting on the brain and pituitary to modulate reproductive physiology and behavior. However, little information is available in teleosts regarding the intracellular signal transduction pathway in response to GnIH. To this end, we first cloned the gene of LPXRFa (the piscine ortholog of GnIH) receptor in the half-smooth tongue sole (Cynoglossus semilaevis), a representative species of the order Pleuronectiformes. The full-length cDNA of LPXRFa receptor was 2201 bp in size with an open reading frame (ORF) of 1365 bp that encoded 454 amino acids. Tissue distribution showed that LPXRFa receptor transcripts could be detected at high levels in the brain, to a lesser extent in the pituitary, and at low levels in the ovary and other peripheral tissues. In vitro functional analysis revealed that putative tongue sole LPXRFa-1 and LPXRFa-2 peptides significantly stimulated serum responsive element-dependent luciferase (SRE-luc) activity in COS-7 cells transfected with the novel receptor, and these stimulatory effects were evidently reduced by two inhibitors of the PLC/PKC pathway. In addition, neither LPXRFa-1 nor LPXRFa-2 altered the cAMP-responsive element (CRE)-luc activity, but only LPXRFa-2 could markedly decrease forskolin-induced CRE-luc activity in COS-7 cells expressing its cognate receptor. Taken together, our results encompass the first study reporting the existence of LPXRFa receptor in the order Pleuronectiformes and provide novel evidence of differential activation of signaling pathways by LPXRFa peptides in fish.

      PubDate: 2018-05-29T04:34:03Z
       
  • The effect of syndecan-4 and glypican-1 knockdown on the proliferation and
           differentiation of turkey satellite cells differing in age and growth
           rates
    • Abstract: Publication date: September 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 223
      Author(s): Sandra G. Velleman, Daniel L. Clark, Jeffrey R. Tonniges
      Posthatch skeletal muscle growth requires myogenic satellite cells and the dynamic expression of cell membrane-associated proteins. The membrane associated heparan sulfate proteoglycans, syndecan-4 and glypican-1, link the satellite cell niche to the intracellular environment. Sydnecan-4 and glypican-1 are differentially expressed with age in turkey satellite cells and their over-expression impacts both satellite cell proliferation and differentiation, but their effect on satellite cells from lines with different growth potentials is not known. The objective of the current study was to determine if syndecan-4 and glypican-1 regulation of satellite cell proliferation and differentiation is affected by age and growth selection. Pectoralis major satellite cells isolated at 1 d, 7 and 16-wk of age from a Randombred Control 2 (RBC2) line and a 16-wk body weight (F) line selected from the RBC2 line turkeys were studied. Syndecan-4 and glypican-1 expression was knocked down in both lines. The F-line cells proliferated faster than RBC2 line cells regardless of age, while differentiation tended to be greater in RBC2 line cells than F-line cells at each age. Syndecan-4 knockdown decreased proliferation at 7- and 16-wk but not 1 d cells, and increased differentiation at 1 d and 7 wk but not 16 wk cells. Glypican-1 knockdown differentially affected proliferation depending on cell age, whereas differentiation was decreased for 7- and 16-wk but not 1 d cells. These data suggest syndecan-4 and glypican-1 differentially affected satellite cell function in an age-dependent manner, but had little impact on differences in proliferation and differentiation due to growth selection.

      PubDate: 2018-05-29T04:34:03Z
       
  • Physiological vagility affects population genetic structure and dispersal
           and enables migratory capacity in vertebrates
    • Abstract: Publication date: September 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 223
      Author(s): Thomas V. Hancock, Michael S. Hedrick
      Vagility is defined as the relative capacity for movement. We developed previously a quantitative metric in vertebrates for physiological vagility (PV), the speed at which an animal can move sustainably, incorporating aerobic capacity, body size, body temperature, and transport costs, allowing quantitative tests of whether PV can explain variation in interclass population genetic structure and behaviors involved in dispersal. We found that PV increased with body mass, correlated with maximal dispersal distances, and was inversely related to genetic structure in multiple vertebrate groups. Here we review these relationships and expand our analysis to include additional groups; we also suggest that PV may be utilized to partially explain variation in migratory capacity between groups. We show a positive correlation between PV and maximum migration distance (MMAX) in most groups that reflects many of the relationships observed between PV and dispersal. Flying birds, marine mammals, and large terrestrial mammals display the greatest MMAX and each of these groups has the highest PV among vertebrate groups, while reptiles and small terrestrial mammals had the lowest PV and MMAX. By contrast, marine turtles have exceptional MMAX but do not possess high PV. We suggest that PV is an important mechanism enabling both dispersal and migratory capacity, and affects genetic structure, but that other life history characteristics also need to be considered.

      PubDate: 2018-05-29T04:34:03Z
       
  • Characterization and expression of Na+/K+-ATPase in gills and kidneys of
           the Teleost fish Oreochromis mossambicus, Oreochromis urolepis hornorum
           and their hybrids in response to salinity challenge
    • Abstract: Publication date: Available online 28 May 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Huaping Zhu, Zhigang Liu, Fengying Gao, Maixin Lu, Yujiao Liu, Huanhuan Su, Dongmei Ma, Xiaoli Ke, Miao Wang, Jianmeng Cao, Mengmeng Yi
      Tilapia (Oreochromis mossambicus, O. urolepis hornorum, their hybrids O. mossambicus♀ × O. hornorum♂ and O. hornorum♀ × O. mossambicus♂) were exposed to a high salinity environment to evaluate their osmoregulatory responses. The plasma osmolality of all the tilapia species were elevated with the salinity challenge. The activities of Na+/K+-ATPase (NKA) in both the gill and kidney showed a similar increased change tendency compared with the control. The distribution of NKA α1 mRNA in all the examined tissues suggested that NKA α1 has a possible housekeeping role for this isoform. The amount of NKA α1 mRNA in the gill and kidney was elevated in the four fishes with similar expression patterns after transfer from freshwater to seawater. The NKAα1 mRNA expression levels in the gill reached their peak level at 24 h after transfer (P < .01) compared to the freshwater group, following decreases in the pretreatment level at 48 h (P > .05). However, the NKAα1 mRNA expression levels in the kidney were not significantly affected with increasing environmental salinity (P > .05). The differences in the responses to saltwater challenge may be associated with differences in saltwater tolerance between the four tilapia. The drastic increase in the plasma osmolality, NKA activities and mRNA expression suggested that the hybrids (O. mossambicus♀ × O. hornorum♂) possess heterosis in salinity responsiveness compared to that of both the parents, indicating a maternal effect on the salinity tolerance of the tilapia hybrids. This study provides a theoretical basis to further study the mechanism of fish osmoregulation response to salinity challenge.

      PubDate: 2018-05-29T04:34:03Z
       
  • Leptin and leptin receptor genes in tongue sole (Cynoglossus semilaevis):
           Molecular cloning, tissue distribution and differential regulation of
           these genes by sex steroids
    • Abstract: Publication date: Available online 28 May 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Yongjiang Xu, Yaxing Zhang, Bin Wang, Xuezhou Liu, Quan Liu, Xuesong Song, Bao Shi, Kangli Ren
      Leptin (Lep) is a key factor for the regulation of food intake and energy homeostasis in mammals. To date, a number of studies have provided evidence for the existence of multiple leptin genes in teleosts, but not much information is available in fish regarding the regulation of leptin genes by sex steriods. As a first step, two leptin genes (lepa and lepb) and a leptin receptor (lepr) gene were cloned from the half-smooth tongue sole (Cynoglossus semilaevis), a representative species of the order Pleuronectiformes. The full-length cDNAs of tongue sole lepa and lepb were 1265 bp and 1157 bp in length, encoding for proteins of 160 aa and 158 aa, respectively. The three-dimensional structures modeling of tongue sole LepA and LepB showed strong conservation of tertiary structure with other vertebrates. The full-length cDNA of tongue sole lepr was 4576 bp, encoding a protein of 1133 aa which contained all functionally important domains conserved among vertebrate LepRs. Tissue distribution analysis showed that tongue sole lepa mRNA was highly detectable in the ovary and brain, while lepb mRNA was ubiquitously expressed in various tissues. Notably, the tongue sole lepr mRNA was most abundant in the ovary. Using a primary hepatocyte culture system, we evaluated the effects of sex steroids on lep/lepr gene expression. Both 17β-estradiol (E2) and testosterone (T) inhibited hepatic lepa and lepr mRNAs without affecting lepb mRNA levels. In addition, T also suppressed growth hormone receptor 1 (ghr1), ghr2, and insulin-like growth factor 2 (igf-2) mRNA levels, and stimulated expression of igf-1 gene. On the other hand, none of these four genes were altered by E2. To the best of our knowledge, this is the first description of a direct and differential regulation of lep/lepr gene expression by sex steroids at the hepatocyte level of a flatfish, supporting that individual leptin peptide may possess different biological roles in teleosts.

      PubDate: 2018-05-29T04:34:03Z
       
  • Localization and expression of putative circadian clock transcripts in the
           brain of the nudibranch Melibe leonina
    • Abstract: Publication date: Available online 9 May 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Victoria E. Duback, M. Sabrina Pankey, Rachel I. Thomas, Taylor L. Huyck, Izhar M. Mbarani, Kyle R. Bernier, Geoffrey M. Cook, Colleen A. O'Dowd, James M. Newcomb, Winsor H. Watson
      The nudibranch, Melibe leonina, expresses a circadian rhythm of locomotion, and we recently determined the sequences of multiple circadian clock transcripts that may play a role in controlling these daily patterns of behavior. In this study, we used these genomics data to help us: 1) identify putative clock neurons using fluorescent in situ hybridization (FISH); and 2) determine if there is a daily rhythm of expression of clock transcripts in the M. leonina brain, using quantitative PCR. FISH indicated the presence of the clock-related transcripts clock, period, and photoreceptive and non-photoreceptive cryptochrome (pcry and npcry, respectively) in two bilateral neurons in each cerebropleural ganglion and a group of <10 neurons in the anterolateral region of each pedal ganglion. Double-label experiments confirmed colocalization of all four clock transcripts with each other. Quantitative PCR demonstrated that the genes clock, period, pcry and npcry exhibited significant differences in expression levels over 24 h. These data suggest that the putative circadian clock network in M. leonina consists of a small number of identifiable neurons that express circadian genes with a daily rhythm.

      PubDate: 2018-05-29T04:34:03Z
       
  • Sex-specific transcription and DNA methylation profiles of reproductive
           and epigenetic associated genes in the gonads and livers of breeding
           zebrafish
    • Authors: L.V. Laing; J. Viana; E. Dempster; T.M. Uren Webster; R. van Aerle; J. Mill; E.M. Santos
      Abstract: Publication date: Available online 12 April 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): L.V. Laing, J. Viana, E. Dempster, T.M. Uren Webster, R. van Aerle, J. Mill, E.M. Santos
      Reproduction is an essential process for life and is regulated by complex hormone networks and environmental factors. To date, little is known about the contribution of epigenetic mechanisms to the regulation of reproduction, particularly in lower vertebrates. We used the zebrafish (Danio rerio) model to investigate the sex-specific transcription and DNA methylation profiles for genes involved in the regulation of reproduction and in epigenetic signalling in the livers and gonads. We found evidence for associations between DNA promotor methylation and transcription for esr1 (gonads and female livers), amh (gonads) and dnmt1 (livers). In the liver, esr1 was shown to be significantly over-expressed in females compared to males, and its promoter was significantly hypo-methylated in females compared to males. In the gonads, genes involved in epigenetic processes including dnmt1, dnmt3 and hdac1 were over-expressed in the ovary compared to the testis. In addition, dnmt1 and dnmt3 transcription in the testis was found to be strongly correlated with global DNA methylation. These data provide evidence of the sex-specific epigenetic regulation and transcription of genes involved in reproduction and epigenetic signalling in a commonly used vertebrate model.

      PubDate: 2018-04-18T10:19:10Z
      DOI: 10.1016/j.cbpa.2018.04.004
       
  • The effects of morphine on gas exchange, ventilation pattern and
           ventilatory responses to hypercapnia and hypoxia in dwarf caiman
           (Paleosuchus palpebrosus)
    • Authors: Christian Lind Malte; Jonas Bundgaard; Michael Schou Jensen; Mads Frost Bertelsen; Tobias Wang
      Abstract: Publication date: Available online 17 March 2018
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Christian Lind Malte, Jonas Bundgaard, Michael Schou Jensen, Mads Frost Bertelsen, Tobias Wang
      Morphine and other opioids cause respiratory depression in high doses and lower the ventilatory responses to hypoxia and hypercapnia in mammals. Recent studies indicate that turtles respond similarly, but although they are used routinely for post-surgical analgesia, little is known about the physiological effects of opioids in reptiles. We therefore investigated the effects of morphine (10 and 20 mg kg−1) on gas exchange and ventilation in six dwarf caiman (Paleosuchus palpebrosus) using pneumotachography in a crossover design. Intraperitoneal injections of morphine changed the ventilation pattern from a typical intermittent/periodic pattern with a few or several breaths in ventilatory bouts to single breaths and prolonged the apnoea, such that respiratory frequency was depressed, whilst tidal volume was elevated. Furthermore, the duration of inspiration and especially expiration was prolonged. The resulting decrease in minute ventilation was attended by a lowering of the respiratory exchange ratio (RER) (especially for 20 mg kg−1 dose) indicating CO2 retention with a long time constant for approaching the new steady state. The changes in ventilation pattern and gas exchange reached a new stable level approximately 3 h after the morphine injection and did not significantly affect steady state O2 uptake, i.e. O2 consumption. As expected, the ventilatory response to 5% O2 was lower in morphine-treated caimans, but minute ventilation upon exposure to 2% CO2 did not differ significantly different from control animals.

      PubDate: 2018-03-19T06:59:32Z
      DOI: 10.1016/j.cbpa.2018.03.008
       
 
 
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