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BIOCHEMISTRY (230 journals)                  1 2     

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AAPS PharmSciTech     Hybrid Journal   (Followers: 6)
Acetic Acid Bacteria     Open Access   (Followers: 1)
ACS Central Science     Open Access   (Followers: 4)
ACS Chemical Biology     Full-text available via subscription   (Followers: 180)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 15)
Acta Crystallographica Section D : Biological Crystallography     Hybrid Journal   (Followers: 10)
Acta Crystallographica Section F: Structural Biology Communications     Hybrid Journal   (Followers: 7)
Advances and Applications in Bioinformatics and Chemistry     Open Access   (Followers: 9)
Advances in Biological Chemistry     Open Access   (Followers: 7)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 7)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 14)
African Journal of Biochemistry Research     Open Access   (Followers: 1)
African Journal of Chemical Education     Open Access   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
American Journal of Biochemistry     Open Access   (Followers: 7)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 60)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 13)
American Journal of Polymer Science     Open Access   (Followers: 22)
Amino Acids     Hybrid Journal   (Followers: 8)
Analytical Biochemistry     Hybrid Journal   (Followers: 140)
Angiogenesis     Hybrid Journal   (Followers: 3)
Annals of Clinical Biochemistry     Hybrid Journal   (Followers: 8)
Annual Review of Biochemistry     Full-text available via subscription   (Followers: 50)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 9)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 43)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 16)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 5)
Archives of Biochemistry and Biophysics     Hybrid Journal   (Followers: 22)
Archives of Insect Biochemistry and Physiology     Hybrid Journal  
Archives Of Physiology And Biochemistry     Hybrid Journal   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Avicenna Journal of Medical Biochemistry     Open Access  
Bangladesh Journal of Medical Biochemistry     Open Access   (Followers: 2)
BBA Clinical     Open Access  
BBR : Biochemistry and Biotechnology Reports     Open Access   (Followers: 4)
Biocatalysis     Open Access  
Biochemical and Biophysical Research Communications     Hybrid Journal   (Followers: 19)
Biochemical and Molecular Medicine     Full-text available via subscription   (Followers: 4)
Biochemical Compounds     Open Access  
Biochemical Engineering Journal     Hybrid Journal   (Followers: 13)
Biochemical Genetics     Hybrid Journal   (Followers: 3)
Biochemical Journal     Full-text available via subscription   (Followers: 25)
Biochemical Pharmacology     Hybrid Journal   (Followers: 7)
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: 232)
Biochemistry & Pharmacology : Open Access     Open Access   (Followers: 3)
Biochemistry & Physiology : Open Access     Open Access  
Biochemistry (Moscow)     Hybrid Journal   (Followers: 4)
Biochemistry (Moscow) Supplement Series A: Membrane and Cell Biology     Hybrid Journal   (Followers: 3)
Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry     Hybrid Journal   (Followers: 3)
Biochemistry and Biophysics Reports     Open Access  
Biochemistry and Cell Biology     Full-text available via subscription   (Followers: 15)
Biochemistry and Molecular Biology Education     Hybrid Journal   (Followers: 5)
Biochemistry and Molecular Biology of Fishes     Full-text available via subscription   (Followers: 1)
Biochemistry Research International     Open Access   (Followers: 5)
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids     Hybrid Journal   (Followers: 9)
Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease     Hybrid Journal   (Followers: 16)
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research     Hybrid Journal   (Followers: 7)
Biochimie     Hybrid Journal   (Followers: 6)
Biochimie Open     Open Access  
Bioconjugate Chemistry     Full-text available via subscription   (Followers: 30)
BioDrugs     Full-text available via subscription   (Followers: 8)
Bioelectrochemistry     Hybrid Journal   (Followers: 1)
Biofuels     Hybrid Journal   (Followers: 10)
Biogeochemistry     Hybrid Journal   (Followers: 11)
BioInorganic Reaction Mechanisms     Hybrid Journal   (Followers: 1)
Biokemistri     Open Access  
Biological Chemistry     Partially Free   (Followers: 26)
Biomaterials Research     Open Access   (Followers: 4)
Biomedicines     Open Access   (Followers: 1)
BioMolecular Concepts     Hybrid Journal   (Followers: 2)
Bioscience, Biotechnology, and Biochemistry     Hybrid Journal   (Followers: 25)
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: 7)
Cell Biochemistry and Biophysics     Hybrid Journal   (Followers: 5)
Cell Biochemistry and Function     Hybrid Journal   (Followers: 4)
Cellular Physiology and Biochemistry     Open Access   (Followers: 3)
ChemBioChem     Hybrid Journal   (Followers: 6)
Chemical and Biological Technologies for Agriculture     Open Access  
Chemical Biology & Drug Design     Hybrid Journal   (Followers: 21)
Chemical Engineering Journal     Hybrid Journal   (Followers: 27)
Chemical Senses     Hybrid Journal   (Followers: 1)
Chemical Speciation and Bioavailability     Open Access   (Followers: 1)
Chemico-Biological Interactions     Hybrid Journal   (Followers: 3)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 5)
Chemistry & Biology     Full-text available via subscription   (Followers: 29)
Chemistry and Ecology     Hybrid Journal  
ChemTexts     Hybrid Journal  
Clinica Chimica Acta     Hybrid Journal   (Followers: 36)
Clinical Biochemist Reviews     Full-text available via subscription   (Followers: 1)
Clinical Biochemistry     Hybrid Journal   (Followers: 19)
Clinical Chemistry     Full-text available via subscription   (Followers: 67)
Clinical Chemistry and Laboratory Medicine     Hybrid Journal   (Followers: 62)
Clinical Lipidology     Full-text available via subscription  
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology     Hybrid Journal   (Followers: 5)
Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 2)
Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology     Hybrid Journal   (Followers: 7)
Comparative Biochemistry and Physiology Part D: Genomics and Proteomics     Hybrid Journal   (Followers: 3)
Comprehensive Biochemistry     Full-text available via subscription   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 9)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 4)
Current Chemical Biology     Hybrid Journal   (Followers: 2)
Current Medicinal Chemistry     Hybrid Journal   (Followers: 14)
Current Opinion in Chemical Biology     Hybrid Journal   (Followers: 21)
Current Opinion in Lipidology     Hybrid Journal   (Followers: 5)
DNA Barcodes     Open Access  
Doklady Biochemistry and Biophysics     Hybrid Journal   (Followers: 1)
Doklady Chemistry     Hybrid Journal  
Egyptian Journal of Biochemistry and Molecular Biology     Full-text available via subscription  
FABICIB     Open Access  
FEBS Letters     Hybrid Journal   (Followers: 58)
FEBS Open Bio     Open Access   (Followers: 3)
Fish Physiology and Biochemistry     Hybrid Journal   (Followers: 4)
Food & Function     Full-text available via subscription   (Followers: 5)
Foundations of Modern Biochemistry     Full-text available via subscription  
Free Radicals and Antioxidants     Full-text available via subscription   (Followers: 3)
Frontiers in Molecular Biosciences     Open Access   (Followers: 2)
Frontiers in Natural Product Chemistry     Hybrid Journal  
Global Biogeochemical Cycles     Full-text available via subscription   (Followers: 12)
Green Chemistry     Full-text available via subscription   (Followers: 9)
Histochemistry and Cell Biology     Hybrid Journal   (Followers: 4)
Indian Journal of Biochemistry and Biophysics (IJBB)     Open Access   (Followers: 3)
Indian Journal of Clinical Biochemistry     Hybrid Journal   (Followers: 1)
Indonesian Biomedical Journal     Open Access  
Insect Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 3)
International Journal of Biochemistry & Cell Biology     Hybrid Journal   (Followers: 7)
International Journal of Biochemistry and Biophysics     Open Access   (Followers: 1)
International Journal of Biological Chemistry     Open Access   (Followers: 4)
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 5)
International Journal of Food Contamination     Open Access  
International Journal of Plant Physiology and Biochemistry     Open Access  
International Journal of Plant Research     Open Access   (Followers: 3)
International Journal of Secondary Metabolite     Open Access   (Followers: 1)
Invertebrate Immunity     Open Access   (Followers: 1)
JBIC Journal of Biological Inorganic Chemistry     Hybrid Journal   (Followers: 4)
Journal of Microbial & Biochemical Technology     Open Access   (Followers: 1)
Journal of Applied Biology & Biotechnology     Open Access   (Followers: 1)
Journal of Bioactive and Compatible Polymers     Hybrid Journal   (Followers: 2)
Journal of Biochemistry     Hybrid Journal   (Followers: 42)
Journal of Biological Chemistry     Full-text available via subscription   (Followers: 175)
Journal of Biomaterials Science, Polymer Edition     Hybrid Journal   (Followers: 9)
Journal of Carbohydrate Chemistry     Hybrid Journal   (Followers: 7)
Journal of Cellular Biochemistry     Hybrid Journal   (Followers: 5)
Journal of Chemical Biology     Hybrid Journal   (Followers: 1)
Journal of Chemical Neuroanatomy     Hybrid Journal  
Journal of Clinical Lipidology     Hybrid Journal   (Followers: 1)
Journal of Comparative Physiology B : Biochemical, Systemic, and Environmental Physiology     Hybrid Journal   (Followers: 4)
Journal of Drug Discovery and Therapeutics     Open Access   (Followers: 1)
Journal of Enzyme Inhibition and Medicinal Chemistry     Hybrid Journal   (Followers: 4)
Journal of Evolutionary Biochemistry and Physiology     Hybrid Journal  
Journal of Food and Drug Analysis     Open Access  
Journal of Forensic Toxicology and Pharmacology     Hybrid Journal   (Followers: 3)
Journal of Inborn Errors of Metabolism and Screening     Open Access  
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 4)
Journal of Investigational Biochemistry     Open Access   (Followers: 2)
Journal of Medical and Biomedical Sciences     Open Access  
Journal of Medical Biochemistry     Open Access   (Followers: 4)
Journal of Medicine and Biomedical Research     Open Access   (Followers: 1)
Journal of Molecular Biochemistry     Open Access   (Followers: 3)
Journal of Molecular Diagnostics     Hybrid Journal   (Followers: 6)
Journal of Neurochemistry     Hybrid Journal   (Followers: 3)
Journal of Nutritional Biochemistry     Hybrid Journal   (Followers: 7)
Journal of Pediatric Biochemistry     Hybrid Journal   (Followers: 1)
Journal of Peptide Science     Hybrid Journal   (Followers: 24)
Journal of Photochemistry and Photobiology B: Biology     Hybrid Journal   (Followers: 3)
Journal of Physiobiochemical Metabolism     Hybrid Journal   (Followers: 1)
Journal of Physiology and Biochemistry     Hybrid Journal   (Followers: 3)
Journal of Plant Biochemistry and Biotechnology     Hybrid Journal   (Followers: 5)
Journal of Steroid Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 2)
Journal of Virology & Antiviral Research     Hybrid Journal   (Followers: 3)
Journal of Wood Chemistry and Technology     Hybrid Journal   (Followers: 7)
La Rivista Italiana della Medicina di Laboratorio - Italian Journal of Laboratory Medicine     Hybrid Journal  
Lab on a Chip     Full-text available via subscription   (Followers: 33)
Marine Chemistry     Hybrid Journal   (Followers: 6)
Methods in Enzymology     Full-text available via subscription   (Followers: 11)
Molecular and Biochemical Parasitology     Hybrid Journal   (Followers: 2)
Molecular and Cellular Biochemistry     Hybrid Journal   (Followers: 4)
Molecular Aspects of Medicine     Hybrid Journal   (Followers: 5)
Molecular Informatics     Hybrid Journal   (Followers: 4)
Molecular inhibitors in targeted therapy     Open Access  
Moscow University Chemistry Bulletin     Hybrid Journal   (Followers: 1)
Mycology : An International Journal on Fungal Biology     Hybrid Journal   (Followers: 4)
Natural Products and Bioprospecting     Open Access   (Followers: 3)
Nature Chemical Biology     Full-text available via subscription   (Followers: 67)
Nature Communications     Open Access   (Followers: 109)
Neurosignals     Open Access   (Followers: 2)
Novelty in Biomedicine     Open Access  
Ocean Acidification     Open Access   (Followers: 3)
Organic & Biomolecular Chemistry     Full-text available via subscription   (Followers: 85)
Peptidomics     Open Access  
Pesticide Biochemistry and Physiology     Hybrid Journal   (Followers: 4)
Pflugers Archiv European Journal of Physiology     Hybrid Journal   (Followers: 3)
Pharmaceutical Bioprocessing     Full-text available via subscription   (Followers: 1)
Pharmacognosy Magazine     Open Access   (Followers: 2)

        1 2     

Journal Cover Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
  [SJR: 0.939]   [H-I: 84]   [5 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1095-6433
   Published by Elsevier Homepage  [3038 journals]
  • The metabolic consequences of repeated anoxic stress in the western
           painted turtle, Chrysemys picta bellii
    • Authors: Daniel E. Warren; Donald C. Jackson
      Pages: 1 - 8
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Daniel E. Warren, Donald C. Jackson
      The painted turtle is known for its extreme tolerance to anoxia, but it is unknown whether previous experience with anoxic stress might alter physiological performance during or following a test bout of anoxia. Repeatedly subjecting 25°C-acclimated painted turtles to 2h of anoxic stress every other day for 19days (10 submergence bouts total) caused resting levels of liver glycogen to decrease by 17% and liver citrate synthase (CS) and cytochrome oxidase (COX) activities to increase by 33% and 112%, respectively. When the repeatedly submerged turtles were studied during a subsequent anoxic stress test, liver COX and CS activities decreased during anoxia to the same levels of naïve turtles, which were unchanged, and remained there throughout metabolic recovery. There were no effects of the repeated anoxia treatment on any of the other measured variables, which included lactate dehydrogenase and phosphofructokinase activities in liver, skeletal muscle, and ventricle, blood acid-base status, hemoglobin, hematocrit and plasma ion (Na, K, Ca, Mg, Cl) and metabolite concentrations (lactate, glucose, free-fatty acids), before, during, or after the anoxic stress test. We conclude that although painted turtles can show a physiological reaction to repeated anoxic stress, the changes appear to have no measurable effect on anaerobic physiological performance or ability to recover from anoxia.

      PubDate: 2016-08-12T12:14:02Z
      DOI: 10.1016/j.cbpa.2016.07.012
      Issue No: Vol. 203 (2016)
  • Molecular cloning of kisspeptin receptor genes (gpr54-1 and gpr54-2) and
           their expression profiles in the brain of a tropical damselfish during
           different gonadal stages
    • Authors: Satoshi Imamura; Sung-Pyo Hur; Yuki Takeuchi; Selma Bouchekioua; Akihiro Takemura
      Pages: 9 - 16
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Satoshi Imamura, Sung-Pyo Hur, Yuki Takeuchi, Selma Bouchekioua, Akihiro Takemura
      The kisspeptin receptor (GPR54) mediates neuroendocrine control of kisspeptin in the brain and acts as a gateway for a pulsatile release of hypothalamic gonadotropin-releasing hormone. This study aimed to clone two GPR54 genes (gpr54-1 and gpr54-2) from the brain of the sapphire devil Chrysiptera cyanea, a tropical damselfish, and to study their involvement in reproduction. The partial sequences of the sapphire devil gpr54-1 cDNA (1059bp) and gpr54-2 cDNA (1098bp) each had an open reading frame encoding a protein of 353 and 366 amino acids, respectively, both of which had structural features of a G-protein-coupled receptor. The expression of gpr54-1 mRNA was observed in the diencephalon and telencephalon, and gpr54-2 mRNA was found in the optic tectum of sapphire devil. When gpr54-1 and gpr54-2 mRNA levels were examined in the brain of sapphire devil by real-time quantitative polymerase chain reaction (qPCR), they were found to increase during late vitellogenesis and post-spawning. Treatment of fish with estradiol-17β (Ε2) resulted in an increase in gpr54-1 and gpr54-2 expression in the brain of sapphire devil. Thus, kisspeptin receptors likely mediate the activity of kisspeptin in the brain and are involved in controlling reproductive events in a tropical damselfish.

      PubDate: 2016-08-12T12:14:02Z
      DOI: 10.1016/j.cbpa.2016.07.015
      Issue No: Vol. 203 (2016)
  • The contribution of heart rate to the oxygen consumption of the chicken
           embryo during cold- or hypoxia-hypometabolism
    • Authors: Satoko Tomita Ide; Ryoji Ide; Jacopo P. Mortola
      Pages: 49 - 58
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Satoko Tomita Ide, Ryoji Ide, Jacopo P. Mortola
      In embryos, cooling and hypoxia cause a decrease in oxygen consumption ( V ̇ O 2 ); we asked what was the relative contribution of heart rate (HR) and of the ‘not-HR’ factor (the product of stroke volume and arterial-venous O2 difference) to the drop in V ̇ O 2 . Data of HR (with subcutaneous electrodes) and V ̇ O 2 (by an open-flow methodology) were collected simultaneously on chicken embryos close to end-incubation. Over the last four days of incubation (E16–E20) differences in HR contributed about 30% of the differences in resting V ̇ O 2 among embryos. At E20, progressive cooling from 38 to 8°C decreased V ̇ O 2 entirely because of the decrease in HR, with minimal compensation of the ‘not-HR’ component. The same pattern during cooling occurred in younger embryos (age E16), in E20 embryos simultaneously exposed to hypoxia (15% O2) and in E20 normoxic embryos which were incubated in hypoxia (15% O2). Differently, in E20 embryos in normothermia, progressive hypoxia (15%, 10% or 5% O2) lowered V ̇ O 2 largely because of the reduction in the ‘not-HR’ component. We conclude that at end incubation during hypometabolism the changes in HR contribute very differently to the decrease in V ̇ O 2 , from about the totality of it during cold to only about 10–20% during hypoxia, depending on its severity. It follows that during cold-hypometabolism, but not during hypoxic hypometabolism, the changes in HR are a good index of the changes in V ̇ O 2 . The close relationship between V ̇ O 2 and HR during cold-hypometabolism may permit estimates of the changes in V ̇ O 2 from the changes in HR in infants undergoing therapeutic hypothermia.

      PubDate: 2016-09-05T15:15:08Z
      DOI: 10.1016/j.cbpa.2016.08.026
      Issue No: Vol. 203 (2016)
  • The expression of VILL protein is hypoosmotic-dependent in the lamellar
           gill ionocytes of Otocephala teleost fish, Chanos chanos
    • Authors: Chao-Kai Kang; Chia-Shian Lin; Yao-Chung Hu; Shu-Chuan Tsai; Tsung-Han Lee
      Pages: 59 - 68
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Chao-Kai Kang, Chia-Shian Lin, Yao-Chung Hu, Shu-Chuan Tsai, Tsung-Han Lee
      Milkfish, a species within the primitive teleost lineage Otocephala, can survive in water conditions ranging from hypo- to hyper-saline. This study explored the effects of environmental salinity on apical morphologies of ionocytes and the expression of villin homologs in the gills of milkfish acclimated to either seawater (SW) or fresh water (FW). Scanning electron microscopy revealed that the ionocytes in the gill filaments of SW and FW milkfish, respectively, cellular apical morphologies were hole-type and squint-type. The flat-type ionocytes were observed in the gill lamellae of FW milkfish. Furthermore, apical surfaces of some lamellar ionocytes exhibited microvilli. Villin 1 is a microvilli marker expressed in the epithelial cells of various vertebrates. In the phylogenetic tree of villin 1 homologs, primitive teleosts exhibit villin 1-like (VILL) and villin 1 proteins. Two mRNA sequences, villin 1 and VILL, were identified from the milkfish transcriptome by next generation sequencing. Low but constant expression of villin 1 (gene and protein) was observed in the gills for both SW and FW fish. VILL gene and protein expression levels in the gills were higher in FW fish, compared to SW fish. Double immunofluorescence staining demonstrated that VILL protein was present in some lamellar ionocytes of FW milkfish, but not in the filament ionocytes of either FW or SW milkfish. Taken together, these findings indicated that the VILL expression of ionocytes is hypoosmotic-dependent. The VILL might be involved in the formation of microvilli in the lamellar ionocytes for hyperosmoregulation of the milkfish.

      PubDate: 2016-09-05T15:15:08Z
      DOI: 10.1016/j.cbpa.2016.08.016
      Issue No: Vol. 203 (2016)
  • Rumen content stratification in the giraffe (Giraffa camelopardalis)
    • Authors: Cathrine Sauer; Marcus Clauss; Mads F. Bertelsen; Martin R. Weisbjerg; Peter Lund
      Pages: 69 - 76
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Cathrine Sauer, Marcus Clauss, Mads F. Bertelsen, Martin R. Weisbjerg, Peter Lund
      Ruminants differ in the degree of rumen content stratification, with ‘cattle-types’ (i.e., the grazing and intermediate feeding ruminants) having stratified content, whereas ‘moose-types’ (i.e., the browsing ruminants) have unstratified content. The feeding ecology, as well as the digestive morphophysiology of the giraffe (Giraffa camelopardalis), suggest that it is a ‘moose-type’ ruminant. Correspondingly, the giraffe should have an unstratified rumen content and an even rumen papillation pattern. Digesta samples were collected from along the digestive tract of 27 wild-caught giraffes kept in bomas for up to 2months, and 10 giraffes kept in zoological gardens throughout their lives. Samples were analysed for concentration of dry matter, fibre fractions, volatile fatty acids and NH3, as well as mean particle size and pH. There was no difference between the dorsal and ventral rumen region in any of these parameters, indicating homogenous rumen content in the giraffes. In addition to the digesta samples, samples of dorsal rumen, ventral rumen and atrium ruminis mucosa were collected and the papillary surface enlargement factor was determined, as a proxy for content stratification. The even rumen papillation pattern observed also supported the concept of an unstratified rumen content in giraffes. Zoo giraffes had a slightly more uneven papillation pattern than boma giraffes. This finding could not be matched by differences in physical characteristics of the rumen content, probably due to an influence of fasting time ante mortem on these parameters.

      PubDate: 2016-09-10T15:33:25Z
      DOI: 10.1016/j.cbpa.2016.08.033
      Issue No: Vol. 203 (2016)
  • Metabolic responses to chronic hypoxic incubation in embryonic American
           alligators (Alligator mississippiensis)
    • Authors: Dane A. Crossley; Rick Ling; Derek Nelson; Taylor Gillium; Justin Conner; James Hapgood; Ruth M. Elsey; John Eme
      Pages: 77 - 82
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Dane A. Crossley, Rick Ling, Derek Nelson, Taylor Gillium, Justin Conner, James Hapgood, Ruth M. Elsey, John Eme
      Chronic hypoxic incubation is a common tool used to study developmental changes in reduced O2 conditions, and it has been useful for identifying phenotypically plastic periods during ontogeny in laboratory settings. Reptilian embryos can be subjected to natural hypoxia due to nesting strategy, and recent studies have been important in establishing the phenotypic responses of several species to low developmental oxygen. In particular, the cardiovascular responses of American alligators (Alligator mississippiensis) to low developmental oxygen have been detailed, including a substantial cardiac enlargement that may support a higher mass specific metabolic rate. However, embryo mass-specific metabolic demands of hypoxic incubated alligator embryos have not been measured. In this study, alligator eggs were incubated in 10% O2 (H) or 21% O2 (N) environments for the entire course of embryonic development. Acute metabolic measures in 21% and 10% O2 were taken for both H and N groups. We hypothesized that acute 10% O2 exposure has no impact on metabolic rate of embryonic alligators, and that metabolic rate is unaffected by chronic hypoxic incubation when studied in embryos measured at 21% O2. Our findings suggest phenotypic changes resulting from hypoxic incubation early in incubation, in particular relative cardiac enlargement, enable embryonic alligators to sustain metabolic rate during acute hypoxic exposure.

      PubDate: 2016-09-10T15:33:25Z
      DOI: 10.1016/j.cbpa.2016.08.017
      Issue No: Vol. 203 (2016)
  • Octopamine cyclic release and its modulation of visual sensitivity in
    • Authors: Leonardo Rodríguez-Sosa; Gabina Calderón-Rosete; Aída Ortega-Cambranis; Francisco F. De-Miguel
      Pages: 83 - 90
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Leonardo Rodríguez-Sosa, Gabina Calderón-Rosete, Aída Ortega-Cambranis, Francisco F. De-Miguel
      The biogenic amine octopamine (OA) modulates invertebrate behavior by changing neuronal responses from sensory inputs to motor outputs. However, the OA modulation of visual sensitivity and its possible coupling to diurnal cycles remains unexplored. Here we studied the diurnal variations in the OA levels in the hemolymph of the crayfish Procambarus clarkii, its release from the structures in the eyestalk and its modulation of the retinal light sensitivity. The hemolymph concentration of OA and its amino acid precursor tyrosine was measured by high-resolution liquid chromatography; OA varied along the 24-hcycle. The peak value appeared about 2h before the light offset which preceded the peak locomotor activity. OA was found in every structure of the eyestalk but displayed higher levels in the retina–lamina ganglionaris. Moreover, OA was released from isolated eyestalks at a rate of 92nmol/eyestalk/min and a calcium-dependent release was evoked by incubation in a high potassium solution. OA injected into dark-adapted crayfish or applied to the isolated retina at concentrations of 1, 10 and 100μM produced a proportionally increasing reduction in the amplitude of the photoreceptor light responses. These OA concentrations did not affect the position of the visual accessory pigments. Our results suggest that OA release in the crayfish eyestalk is coupled to the 24-hcycle to regulate the diurnal reduction of the photoreceptor sensitivity and to favor the expression of exploratory locomotion during the dark phase of the circadian cycle.

      PubDate: 2016-09-10T15:33:25Z
      DOI: 10.1016/j.cbpa.2016.08.032
      Issue No: Vol. 203 (2016)
  • The expression of nuclear and membrane estrogen receptors in the European
           eel throughout spermatogenesis
    • Authors: Marina Morini; David S. Peñaranda; M. Carmen Vílchez; Helge Tveiten; Anne-Gaëlle Lafont; Sylvie Dufour; Luz Pérez; Juan F. Asturiano
      Pages: 91 - 99
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Marina Morini, David S. Peñaranda, M. Carmen Vílchez, Helge Tveiten, Anne-Gaëlle Lafont, Sylvie Dufour, Luz Pérez, Juan F. Asturiano
      Estradiol (E2) can bind to nuclear estrogen receptors (ESR) or membrane estrogen receptors (GPER). While mammals possess two nuclear ESRs and one membrane GPER, the European eel, like most other teleosts, has three nuclear ESRs and two membrane GPERs, as the result of a teleost specific genome duplication. In the current study, the expression of the three nuclear ESRs (ESR1, ESR2a and ESR2b) and the two membrane GPERs (GPERa and GPERb) in the brain-pituitary-gonad (BPG) axis of the European eel was measured, throughout spermatogenesis. The eels were first transferred from freshwater (FW) to seawater (SW), inducing parallel increases in E2 plasma levels and the expression of ESRs. This indicates that salinity has a stimulatory effect on the E2 signalling pathway along the BPG axis. Stimulation of sexual maturation by weekly injections of human chorionic gonadotropin (hCG) induced a progressive decrease in E2 plasma levels, and different patterns of expression of ESRs and GPERs in the BPG axis. The expression of nuclear ESRs increased in some parts of the brain, suggesting a possible upregulation due to a local production of E2. In the testis, the highest expression levels of the nuclear ESRs were observed at the beginning of spermatogenesis, possibly mediating the role of E2 as spermatogonia renewal factor, followed by a sharply decrease in the expression of ESRs. Conversely, there was a marked increase observed in the expression of both membrane GPERs throughout spermatogenesis, suggesting they play a major role in the final stages of spermatogenesis.

      PubDate: 2016-09-10T15:33:25Z
      DOI: 10.1016/j.cbpa.2016.08.020
      Issue No: Vol. 203 (2016)
  • Molecular drivers of mitochondrial membrane proliferation in response to
           cold acclimation in threespine stickleback
    • Authors: Kelly Keenan; Megan Hoffman; Kristin Dullen; Kristin M. O'Brien
      Pages: 109 - 114
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Kelly Keenan, Megan Hoffman, Kristin Dullen, Kristin M. O'Brien
      Little is known about how the synthesis of mitochondrial phospholipids is integrated into mitochondrial biogenesis in fish or mammals. Glycerol-3-phosphate acyltransferase (GPAT; EC catalyzes the addition of fatty acyl CoA to the sn-1 position of glycerol-3-phosphate, in what is considered the rate-limiting step in phospholipid biosynthesis. Previous studies have shown that mitochondrial volume density increases in oxidative skeletal muscle but not liver of Gasterosteus aculeatus (threespine stickleback) in response to cold acclimation. We hypothesized that maximal activity of GPAT would increase in oxidative skeletal muscle but not liver during cold acclimation, coinciding with mitochondrial biogenesis. GPAT activity was measured in liver and oxidative skeletal (pectoral adductor) muscle of threespine stickleback acclimated to 8°C or 20°C. In addition, mRNA levels of enzymes involved in phospholipid synthesis, including cytidine diphosphodiacylglycerol synthase-1 (CDS1), CDS2, GPAT1, GPAT2 and 1-acylglycerol 3-phosphate acyltransferase-2 (AGPAT2), were quantified in liver and pectoral muscle of stickleback harvested during cold acclimation. GPAT activity and transcript levels of AGPAT2 increased in response to cold acclimation in pectoral muscle but not liver. Transcript levels of GPAT1 increased in liver but not pectoral muscle. Overall our results suggest that the activity of GPAT, and possibly AGPAT as well, increase during cold acclimation and may contribute to mitochondrial phospholipid biosynthesis required for mitochondrial biogenesis.

      PubDate: 2016-09-15T15:55:04Z
      DOI: 10.1016/j.cbpa.2016.09.001
      Issue No: Vol. 203 (2016)
  • Molecular characterization of a cDNA encoding Na+/K+/2Cl− cotransporter
           in the gill of mud crab (Scylla paramamosain) during the molt cycle:
           Implication of its function in osmoregulation
    • Authors: Bin-peng Xu; Dan-dan Tu; Mao-cang Yan; Miao-an Shu; Qing-jun Shao
      Pages: 115 - 125
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Bin-peng Xu, Dan-dan Tu, Mao-cang Yan, Miao-an Shu, Qing-jun Shao
      Although iono-regulatory processes are critical for survival of crustaceans during the molt cycle, the mechanisms involved are still not clear. The Na+/K+/2Cl− cotransporter (NKCC), a SLC12A family protein that transports Na+, K+ and 2Cl− into cells, is essential for cell ionic and osmotic regulation. To better understand the role of NKCC in the molt osmoregulation, we cloned and characterized a NKCC gene from the mud crab, Scylla paramamosain (designated as SpNKCC). The predicted SpNKCC protein is well conserved, and phylogenetic analysis revealed that this protein was clustered with crustacean NKCC. Expression of SpNKCC was detected in all the tissues examined but was highest in the posterior gills. Transmission electron microscopy revealed that posterior gills had a thick type of epithelium for ion regulation while the anterior gills possessed a thin phenotype related to gas exchange. During the molting cycle, hemolymph osmolality and ion concentrations (Na+ and Cl−) increased significantly over the postmolt period, remained stable in the intermolt and premolt stages and then decreased at ecdysis. Meanwhile, the expression of SpNKCC mRNA was significantly elevated (26.7 to 338.8-fold) at the ion re-establishing stages (postmolt) as compared with baseline molt level. This pattern was consistent with the coordinated regulation of Na+/K+-ATPase α-subunit (NKA α), carbonic anhydrase cytoplasmic (CAc) isoform and Na+/H+ exchanger (NHE) genes in the posterior gills. These data suggest that SpNKCC may be important in mediating branchial ion uptake during the molt cycle, especially at the postmolt stages.

      PubDate: 2016-09-21T01:27:29Z
      DOI: 10.1016/j.cbpa.2016.08.019
      Issue No: Vol. 203 (2016)
  • Involvement of cholecystokinin (CCK) in the daily pattern of
           gastrointestinal regulation of Senegalese sole (Solea senegalensis) larvae
           reared under different feeding regimes
    • Authors: Carmen Navarro-Guillén; Ivar Rønnestad; Ann-Elise Olderbakk Jordal; Francisco Javier Moyano; Manuel Yúfera
      Pages: 126 - 132
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Carmen Navarro-Guillén, Ivar Rønnestad, Ann-Elise Olderbakk Jordal, Francisco Javier Moyano, Manuel Yúfera
      Cholecystokinin (CCK) is an important regulator of pancreatic enzyme secretion in adult mammals and teleosteans. Although some studies have focused on the interaction between CCK and trypsin in marine fish larvae, little is known about the circadian patterns of the regulatory mechanism involving these two digestive components. In this study, we took advantage of the characteristic change from a diurnal to a nocturnal feeding habit that occurs in Senegalese sole (Solea senegalensis) post-larvae, to conduct an experiment where larvae and postlarvae were submitted to three different feeding regimes from mouth opening: continuous feeding, diurnal feeding and nocturnal feeding. The aim was to establish different daily feeding scenarios to uncover the operating mechanisms of CCK and tryptic enzyme activity over the 24-hourcycle to better understand the regulation of digestion in developing fish larvae. Results show a prevalence of simultaneous and opposing trends of CCK level and tryptic activity as a function of the postprandial time. This finding supports the existence of a regulatory loop between these two digestive components in pre- and post-metamorphic Senegal sole larvae. In addition, CCK level was also modulated by the gut content, tending to be lower when the gut is full and higher when is being emptied. Furthermore, larvae were able to synchronize digestive functions to very different feeding regimes, although it seems to be important having a diurnal feeding phase during pre-metamorphic stages for a proper development.

      PubDate: 2016-09-21T01:27:29Z
      DOI: 10.1016/j.cbpa.2016.09.003
      Issue No: Vol. 203 (2016)
  • Salinity responsive aquaporins in the anal papillae of the larval
           mosquito, Aedes aegypti
    • Authors: Hina Akhter; Lidiya Misyura; Phuong Bui; Andrew Donini
      Pages: 144 - 151
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Hina Akhter, Lidiya Misyura, Phuong Bui, Andrew Donini
      The larvae of the mosquito, Aedes aegypti normally inhabit freshwater (FW) where they face dilution of body fluids by osmotic influx of water. In response, the physiological actions of the anal papillae result in ion uptake while the Malpighian tubules and rectum work in concert to excrete excess water. In an apparent paradox, the anal papillae express aquaporins (AQPs) and are sites of water permeability which, if AQPs are expressed by the epithelium, apparently exaggerates the influx of water from their dilute environment. Recently, naturally breeding populations of A. aegypti were found in brackish water (BW), an environment which limits the osmotic gradient. Given that salinization of FW is an emerging environmental issue and that these larvae would presumably need to adjust to these changing conditions, this study investigates the expression of AQPs in the anal papillae and their response to rearing in hypo-osmotic and near isosmotic conditions. Transcripts of all six Aedes AQP homologs were detectable in the anal papillae and the transcript abundance of three AQP homologs in the papillae was different between rearing conditions. Using custom made antibodies, expression of two of these AQP homologs (AQP4 and AQP5) was localized to the syncytial epithelium of the anal papillae. Furthermore, the changes in transcript abundance of these two AQPs between the rearing conditions, were manifested at the protein level. Results suggest that AQP4 and AQP5 play an important physiological role in larval responses to changes in environmental salinity.

      PubDate: 2016-09-21T01:27:29Z
      DOI: 10.1016/j.cbpa.2016.09.008
      Issue No: Vol. 203 (2016)
  • Effects of hyperglycemia on bone metabolism and bone matrix in goldfish
    • Authors: Kei-ichiro Kitamura; Tadashi Andoh; Wakana Okesaku; Yuya Tazaki; Kazuhiro Ogai; Kayo Sugitani; Isao Kobayashi; Nobuo Suzuki; Wenxi Chen; Mika Ikegame; Atsuhiko Hattori
      Pages: 152 - 158
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Kei-ichiro Kitamura, Tadashi Andoh, Wakana Okesaku, Yuya Tazaki, Kazuhiro Ogai, Kayo Sugitani, Isao Kobayashi, Nobuo Suzuki, Wenxi Chen, Mika Ikegame, Atsuhiko Hattori
      Increased risk of fracture associated with type 2 diabetes has been a topic of recent concern. Fracture risk is related to a decrease in bone strength, which can be affected by bone metabolism and the quality of the bone. To investigate the cause of the increased fracture rate in patients with diabetes through analyses of bone metabolism and bone matrix protein properties, we used goldfish scales as a bone model for hyperglycemia. Using the scales of seven alloxan-treated and seven vehicle-treated control goldfish, we assessed bone metabolism by analyzing the activity of marker enzymes and mRNA expression of marker genes, and we measured the change in molecular weight of scale matrix proteins with SDS-PAGE. After only a 2-week exposure to hyperglycemia, the molecular weight of α- and β-fractions of bone matrix collagen proteins changed incrementally in the regenerating scales of hyperglycemic goldfish compared with those of euglycemic goldfish. In addition, the relative ratio of the γ-fraction significantly increased, and a δ-fraction appeared after adding glyceraldehyde—a candidate for the formation of advanced glycation end products in diabetes—to isolated type 1 collagen in vitro. The enzymatic activity and mRNA expression of osteoblast and osteoclast markers were not significantly different between hyperglycemic and euglycemic goldfish scales. These results indicate that hyperglycemia is likely to affect bone quality through glycation of matrix collagen from an early stage of hyperglycemia. Therefore, non-enzymatic glycation of collagen fibers in bone matrix may lead to the deterioration of bone quality from the onset of diabetes.

      PubDate: 2016-09-25T02:12:31Z
      DOI: 10.1016/j.cbpa.2016.09.010
      Issue No: Vol. 203 (2016)
  • Possible role of the leptin system in controlling puberty in the male chub
           mackerel, Scomber japonicus
    • Authors: Hirofumi Ohga; Daisuke Hirata; Kojiro Matsumori; Hajime Kitano; Naoki Nagano; Akihiko Yamaguchi; Michiya Matsuyama
      Pages: 159 - 166
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Hirofumi Ohga, Daisuke Hirata, Kojiro Matsumori, Hajime Kitano, Naoki Nagano, Akihiko Yamaguchi, Michiya Matsuyama
      Leptin directly regulates kisspeptin neurons in the hypothalamus and gonadotropin secretion from the pituitary, making it a central player in the onset of mammalian puberty. Recently, we identified two leptin genes (lepa and lepb) and a single leptin receptor (lepr) in the marine perciform fish chub mackerel; however, the expression of these genes did not correlate with the expression of important reproductive genes or ovarian stage during female puberty. Here, we expand upon these initial observations by evaluating the expression of lepa, lepb, and lepr during pubertal transition and under differential feeding conditions in the male chub mackerel. Reverse transcription-polymerase chain reaction (RT-PCR) showed that lepa was primarily expressed in the liver of pubertal and gonadal recrudescence adults, as well as in the brain of adult fish; lepb was primarily expressed in the brain of all fish tested; and lepr was widely expressed in a variety of tissues. qRT-PCR analyses revealed significant increases in the hepatic expression of lepa in accordance with testicular stage, whereas pituitary follicle-stimulating hormone (fshβ) expression increased in unison with hepatic lepa. In contrast, expression of both brain lepa and lepb dramatically decreased during pubertal transition, with brain kisspeptin 1 (kiss1) expression strongly correlating with leptin expression patterns. In pre-pubertal males, lepa, lepb, and lper gene expression in the brain, pituitary gland, and liver decreased in fish given a high feed diet, relative to the controlled feeding group. Taken together, these results indicate high sexual specificity of leptin expression, suggesting a possible role for leptin signaling in endocrine and neuroendocrine functions during spermatogenesis in the pubertal male chub mackerel.

      PubDate: 2016-09-25T02:12:31Z
      DOI: 10.1016/j.cbpa.2016.09.009
      Issue No: Vol. 203 (2016)
  • Regulating gonad inhibition and vitellogenin/vitellin induction in Penaeus
           monodon using mature GIH fusion protein and polyclonal antisera
    • Authors: Vrinda S.; Jasmin C.; Sivakumar K.C; Seena Jose; Blessy Jose; Rosamma Philip; Bright Singh I. S.
      Pages: 167 - 178
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Vrinda S., Jasmin C., Sivakumar K.C, Seena Jose, Blessy Jose, Rosamma Philip, Bright Singh I. S.
      Gonad inhibiting hormone (GIH), type II class of the CHH family neuropeptides, is released by the neurohaemal XO-SG complex of the eyestalk. The inhibitory function of GIH has a pivotal role in gonad development and reproduction. In this study, we report the expression and production of a thioredoxin-fused mature GIH protein (mf-PmGIH) of Penaeus monodon in a bacterial system and its use as antigen to raise polyclonal antiserum (anti-mf-PmGIH). The mature GIH gene of 237bp that codes for 79 amino acids, was cloned into the Escherichia coli thioredoxin gene fusion expression system. The expression vector construct (mf-PmGIH+pEt32a+) upon induction produced 32.16kDa mature GIH fusion protein (mf-PmGIH)·The purified fusion protein was used as exogenous GIH and as antigen to raise polyclonal antisera. The fusion protein when injected into juvenile shrimp significantly reduced vitellogenin/vitellin levels by 31.55% within 72h in comparison to the controls showing the gonad inhibiting property. Vitellogenin/vitellin levels were significantly induced by 74.10% within 6h when polyclonal antiserum (anti-mf-PmGIH - 1:500) was injected in P. monodon. Anti-mf-PmGIH immunolocalized GIH producing neurosecretory cells in the eyestalk of P. monodon. The present manuscript reports an innovative means of gonad inhibition and vitellogenin/vitellin induction with thioredoxin fused GIH and antisera developed.

      PubDate: 2016-09-25T02:12:31Z
      DOI: 10.1016/j.cbpa.2016.09.007
      Issue No: Vol. 203 (2016)
  • The expression and function of hsp30-like small heat shock protein genes
           in amphibians, birds, fish, and reptiles
    • Authors: John J. Heikkila
      Pages: 179 - 192
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): John J. Heikkila
      Small heat shock proteins (sHSPs) are a superfamily of molecular chaperones with important roles in protein homeostasis and other cellular functions. Amphibians, reptiles, fish and birds have a shsp gene called hsp30, which was also referred to as hspb11 or hsp25 in some fish and bird species. Hsp30 genes, which are not found in mammals, are transcribed in response to heat shock or other stresses by means of the heat shock factor that is activated in response to an accumulation of unfolded protein. Amino acid sequence analysis revealed that representative HSP30s from different classes of non-mammalian vertebrates were distinct from other sHSPs including HSPB1/HSP27. Studies with amphibian and fish recombinant HSP30 determined that they were molecular chaperones since they inhibited heat- or chemically-induced aggregation of unfolded protein. During non-mammalian vertebrate development, hsp30 genes were differentially expressed in selected tissues. Also, heat shock-induced stage-specific expression of hsp30 genes in frog embryos was regulated at the level of chromatin structure. In adults and/or tissue culture cells, hsp30 gene expression was induced by heat shock, arsenite, cadmium or proteasomal inhibitors, all of which enhanced the production of unfolded/damaged protein. Finally, immunocytochemical analysis of frog and chicken tissue culture cells revealed that proteotoxic stress-induced HSP30 accumulation co-localized with aggresome-like inclusion bodies. The congregation of damaged protein in aggresomes minimizes the toxic effect of aggregated protein dispersed throughout the cell. The current availability of probes to detect the presence of hsp30 mRNA or encoded protein has resulted in the increased use of hsp30 gene expression as a marker of proteotoxic stress in non-mammalian vertebrates.

      PubDate: 2016-09-25T02:12:31Z
      DOI: 10.1016/j.cbpa.2016.09.011
      Issue No: Vol. 203 (2016)
  • Assessment of anoxia tolerance and photoperiod dependence of GABAergic
           polarity in the pond snail Lymnaea stagnalis
    • Authors: Leslie T. Buck; Hilary C. Bond; Aqsa Malik
      Pages: 193 - 200
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Leslie T. Buck, Hilary C. Bond, Aqsa Malik
      The pond snail Lymnaea stagnalis is reported to be anoxia-tolerant and if the tolerance mechanism is similar to that of the anoxia-tolerant painted turtle, GABA should play an important role. A potentially confounding factor investigating the role of GABA in anoxia tolerance are reports that GABA has both inhibitory and excitatory effects within L. stagnalis central ganglion. We therefore set out to determine if seasonality or photoperiod has an impact on: 1) the anoxia-tolerance of the intact pond snail, and 2) the response of isolated neuroganglia cluster F neurons to exogenous GABA application. L. stagnalis maintained on a natural summer light cycle were unable to survive any period of anoxic exposure, while those maintained on a natural winter light cycle survived a maximum of 4h. Using intracellular sharp electrode recordings from pedal ganglia cluster F neurons we show that there is a photoperiod dependent shift in the response to GABA. Snails exposed to a 16h:8h light:dark cycle in an environmental chamber (induced summer phenotype) exhibited hyperpolarizing inhibitory responses and those exposed to a 8h:16h light:dark cycle (induced winter phenotype) exhibited depolarizing excitatory responses to GABA application. Using gramicidin-perforated patch recordings we also found a photoperiod dependent shift in the reversal potential for GABA. We conclude that the opposing responses of L. stagnalis central neurons to GABA results from a shift in intracellular chloride concentration that is photoperiod dependent and is likely mediated through the relative efficacy of cation chloride co-transporters. Although the physiological ramifications of the photoperiod dependent shift are unknown this work potentially has important implications for the impact of artificial light pollution on animal health.

      PubDate: 2016-09-30T03:12:53Z
      DOI: 10.1016/j.cbpa.2016.09.016
      Issue No: Vol. 203 (2016)
  • Lipid content and fatty acid profile during lake whitefish embryonic
           development at different incubation temperatures
    • Authors: Casey A. Mueller; Liam Doyle; John Eme; Richard G. Manzon; Christopher M. Somers; Douglas R. Boreham; Joanna Y. Wilson
      Pages: 201 - 209
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Casey A. Mueller, Liam Doyle, John Eme, Richard G. Manzon, Christopher M. Somers, Douglas R. Boreham, Joanna Y. Wilson
      Lipids serve as energy sources, structural components, and signaling molecules during fish embryonic development, and utilization of lipids may vary with temperature. Embryonic energy utilization under different temperatures is an important area of research in light of the changing global climate. Therefore, we examined percent lipid content and fatty acid profiles of lake whitefish (Coregonus clupeaformis) throughout embryonic development at three incubation temperatures. We sampled fertilized eggs and embryos at gastrulation, eyed and fin flutter stages following chronic incubation at temperatures of 1.8, 4.9 and 8.0°C. Hatchlings were also sampled following incubation at temperatures of 3.3, 4.9 and 8.0°C. Fertilized eggs had an initial high percentage of dry mass composed of lipid (percent lipid content; ~29%) consisting of ~20% saturated fatty acids (SFA), ~32% monounsaturated fatty acids (MUFA), ~44% polyunsaturated fatty acids (PUFA), and 4% unidentified. The most abundant fatty acids were 16:0, 16:1, 18:1(n-9c), 20:4(n-6), 20:5(n-3) and 22:6(n-3). This lipid profile matches that of other cold-water fish species. Percent lipid content increased during embryonic development, suggesting protein or other yolk components were preferentially used for energy. Total percentage of MUFA decreased during development, which indicated MUFA were the primary lipid catabolized for energy during embryonic development. Total percentage of PUFA increased during development, driven largely by an increase in 22:6(n-3). Temperature did not influence percent lipid content or percent MUFA at any development stage, and had inconsistent effects on percent SFA and percent PUFA during development. Thus, lake whitefish embryos appear to be highly adapted to low temperatures, and do not alter lipids in response to temperature within their natural incubation conditions.

      PubDate: 2016-10-06T03:59:05Z
      DOI: 10.1016/j.cbpa.2016.09.018
      Issue No: Vol. 203 (2016)
  • Role of potassium and pH on the initiation of sperm motility in the
           European eel
    • Authors: M. Carmen Vílchez; Marina Morini; David S. Peñaranda; Víctor Gallego; Juan F. Asturiano; Luz Pérez
      Pages: 210 - 219
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): M. Carmen Vílchez, Marina Morini, David S. Peñaranda, Víctor Gallego, Juan F. Asturiano, Luz Pérez
      The role of potassium from the seminal plasma and/or the activation media was examined by selectively removing K+ from this media, and by testing the use of K+ channel inhibitors and a K-ionophore. Sperm motility was measured using a CASA system, intracellular K+ and pH were measured by flow cytometry, and sperm head area was measured by ASMA: Automated Sperm Morphometry Analyses. Sperm motility was notably inhibited by the removal of K+ from the seminal plasma and by treatment with the K+ ionophore valinomycin. This therefore indicates that a reduction of K+ levels in the quiescent stage inhibits further motility. The normal decrease in sperm head area induced by seawater activation was altered by the removal of K+ from the seminal plasma, and an increase in the pHi in the quiescent stage was also induced. Intracellular pH (pHi) was quantitatively measured for the first time in European eel spermatozoa, being 7.2 in the quiescent stage and 7.1 post-activation. Intracellular and external pH levels influenced sperm motility both in the quiescent stage and at activation. The alkalinization of the pHi (by NH4Cl) inhibited sperm motility activation, while acidification (by Na-acetate) did not have any effect. Our results indicate that a pH gradient between the sperm cell and the seminal plasma is necessary for sperm motility activation. The presence of the ion K+ in the seminal plasma (or in the extender medium) is necessary in order to maintain sperm volume, intracellular pH and sperm motility.

      PubDate: 2016-10-13T04:48:24Z
      DOI: 10.1016/j.cbpa.2016.09.024
      Issue No: Vol. 203 (2016)
  • Does physiological response to disease incur cost to reproductive ecology
           in a sexually dichromatic amphibian species'
    • Authors: Christina Kindermann; Edward J. Narayan; Jean-Marc Hero
      Pages: 220 - 226
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Christina Kindermann, Edward J. Narayan, Jean-Marc Hero
      It is well known that the disease chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) has contributed to amphibian declines worldwide. The impact of Bd varies, with some species being more susceptible to infection than others. Recent evidence has shown that Bd can have sub-lethal effects, whereby increases in stress hormones have been associated with infection. Could this increased stress response, which is a physiological adaptation that provides an increased resilience against Bd infection, potentially be a trade-off with important life-history traits such as reproduction' We studied this question in adult male frogs of a non-declining species (Litoria wilcoxii). Frogs were sampled for (1) seasonal hormone (testosterone and corticosterone), color and disease profiles, (2) the relationship between disease infection status and hormone levels or dorsal color, (3) subclinical effects of Bd by investigating disease load and hormone level, and (4) reproductive and stress hormone relationships independent of disease. Testosterone levels and color score varied seasonally (throughout the spring/summer months) while corticosterone levels remained stable. Frogs with high Bd prevalence had significantly higher corticosterone levels and lower testosterone levels compared to uninfected frogs, and no differences in color were observed. There was a significant positive correlation between disease load and corticosterone levels, and a significant negative relationship between disease load and testosterone. Our field data provides novel evidence that increased physiological stress response associated with Bd infection in wild frogs, could suppress reproduction by down-regulating gonadal hormones in amphibians, however the impacts on reproductive output is yet to be established.

      PubDate: 2016-10-13T04:48:24Z
      DOI: 10.1016/j.cbpa.2016.09.019
      Issue No: Vol. 203 (2016)
  • The Greenland shark: A new challenge for the oxidative stress theory of
    • Authors: David Costantini; Shona Smith; Shaun S. Killen; Julius Nielsen; John F. Steffensen
      Pages: 227 - 232
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): David Costantini, Shona Smith, Shaun S. Killen, Julius Nielsen, John F. Steffensen
      The free radical theory of ageing predicts that long-lived species should be more resistant to oxidative damage than short-lived species. Although many studies support this theory, recent studies found notable exceptions that challenge the generality of this theory. In this study, we have analysed the oxidative status of the Greenland shark (Somniosus microcephalus), which has recently been found as the longest living vertebrate animal known to science with a lifespan of at least 272years. As compared to other species, the Greenland shark had body mass-corrected values of muscle glutathione peroxidase and red blood cells protein carbonyls (metric of protein oxidative damage) above 75 percentile and below 25 percentile, respectively. None of the biochemical metrics of oxidative status measured in either skeletal muscle or red blood cells were correlated with maximum lifespan of species. We propose that the values of metrics of oxidative status we measured might be linked to ecological features (e.g., adaptation to cold waters and deep dives) of this shark species rather to its lifespan.

      PubDate: 2016-10-13T04:48:24Z
      DOI: 10.1016/j.cbpa.2016.09.026
      Issue No: Vol. 203 (2016)
  • Leptin levels, seasonality and thermal acclimation in the Microbiotherid
           marsupial Dromiciops gliroides: Does photoperiod play a role'
    • Authors: Marcela Franco; Carolina Contreras; Ned J. Place; Francisco Bozinovic; Roberto F. Nespolo
      Pages: 233 - 240
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Marcela Franco, Carolina Contreras, Ned J. Place, Francisco Bozinovic, Roberto F. Nespolo
      Mammals of the Neotropics are characterized by a marked annual cycle of activity, which is accompanied by several physiological changes at the levels of the whole organism, organs and tissues. The physiological characterization of these cycles is important, as it gives insight on the mechanisms by which animals adjust adaptively to seasonality. Here we studied the seasonal changes in blood biochemical parameters in the relict South American marsupial Dromiciops gliroides (“monito del monte” or “little mountain monkey”), under semi-natural conditions. We manipulated thermal conditions in order to characterize the effects of temperature and season on a battery of biochemical parameters, body mass and adiposity. Our results indicate that monitos experience an annual cycle in body mass and adiposity (measured as leptin levels), reaching a maximum in winter and a minimum in summer. Blood biochemistry confirms that the nutritional condition of animals is reduced in summer instead of winter (as generally reported). This was coincident with a reduction of several biochemical parameters in summer, such as betahydroxybutyrate, cholesterol, total protein concentration and globulins. Monitos seem to initiate winter preparation during autumn and reach maximum body reserves in winter. Hibernation lasts until spring, at which time they use fat reserves and become reproductively active. Sexual maturation during summer would be the strongest energetic bottleneck, which explains the reductions in body mass and other parameters in this season. Overall, this study suggests that monitos anticipate the cold season by a complex interaction of photoperiodic and thermal cues.

      PubDate: 2016-10-13T04:48:24Z
      DOI: 10.1016/j.cbpa.2016.09.025
      Issue No: Vol. 203 (2016)
  • Alterations in gene expression during fasting-induced atresia of early
           secondary ovarian follicles of coho salmon, Oncorhynchus kisutch
    • Authors: Yoji Yamamoto; J. Adam Luckenbach; Graham Young; Penny Swanson
      Pages: 1 - 11
      Abstract: Publication date: Available online 16 June 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Yoji Yamamoto, J. Adam Luckenbach, Graham Young, Penny Swanson
      Molecular processes that either regulate ovarian atresia or are consequences of atresia are poorly understood in teleost fishes. We hypothesized that feed restriction that perturbs normal ovarian growth and induces follicular atresia would alter ovarian gene expression patterns. Previtellogenic, two-year old coho salmon (Oncorhynchus kisutch) were subjected to prolonged fasting to induce atresia or maintained on a normal feeding schedule that would promote continued ovarian development. To identify genes that were specifically up- or down-regulated during oocyte growth in healthy, growing fish compared to fasted fish, reciprocal suppression subtractive hybridization (SSH) cDNA libraries were generated using ovaries from fed and fasted animals. Differential expression of genes identified by SSH was confirmed with quantitative PCR. The SSH library representing genes elevated in ovaries of fed fish relative to those of fasted fish contained steroidogenesis-related genes (e.g., hydroxy-delta-5-steroid dehydrogenase), Tgf-beta superfamily members (e.g., anti-Mullerian hormone) and cytoskeletal intermediate filament proteins (e.g., type I keratin s8). Overall, these genes were associated with steroid production, cell proliferation and differentiation, and ovarian epithelialization. The library representing genes elevated in ovaries of fasted fish relative to fed fish contained genes associated with apoptosis (e.g., programmed cell death protein 4), cortical alveoli (e.g., alveolin), the zona pellucida (e.g., zona pellucida protein c), and microtubules (e.g., microtubule associated protein tau). Elevated expression of this suite of genes was likely associated with the initiation of atresia and/or a reduced rate of follicle development in response to fasting. This study revealed ovarian genes involved in normal early secondary oocyte growth and potential early markers of atresia.

      PubDate: 2016-06-18T18:34:03Z
      DOI: 10.1016/j.cbpa.2016.06.016
      Issue No: Vol. 201 (2016)
  • Expression and localization of the Xenopus laevis small heat shock
           protein, HSPB6 (HSP20), in A6 kidney epithelial cells
    • Authors: Imran Khamis; Daniel W. Chan; Cody S. Shirriff; James H. Campbell; John J. Heikkila
      Pages: 12 - 21
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Imran Khamis, Daniel W. Chan, Cody S. Shirriff, James H. Campbell, John J. Heikkila
      Small heat shock proteins (sHSPs) are molecular chaperones that bind to unfolded protein, inhibit the formation of toxic aggregates and facilitate their refolding and/or degradation. Previously, the only sHSPs that have been studied in detail in the model frog system, Xenopus laevis, were members of the HSP30 family and HSPB1 (HSP27). We now report the analysis of X. laevis HSPB6, an ortholog of mammalian HSPB6. X. laevis HSPB6 cDNA encodes a 168 aa protein that contains an α-crystallin domain, a polar C-terminal extension and some possible phosphorylation sites. X. laevis HSPB6 shares 94% identity with a X. tropicalis HSPB6, 65% with turtle, 59% with humans, 49% with zebrafish and only 50% and 43% with X. laevis HSPB1 and HSP30C, respectively. Phylogenetic analysis revealed that X. laevis HSPB6 grouped more closely with mammalian and reptilian HSPB6s than with fish HSPB6. X. laevis recombinant HSPB6 displayed molecular chaperone properties since it had the ability to inhibit heat-induced aggregation of citrate synthase. Immunoblot analysis determined that HSPB6 was present constitutively in kidney epithelial cells and that heat shock treatment did not upregulate HSPB6 levels. While treatment with the proteasomal inhibitor, MG132, resulted in a 2-fold increase in HSPB6 levels, exposure to cadmium chloride produced a slight increase in HSPB6. These findings were in contrast to HSP70, which was enhanced in response to all three stressors. Finally, immunocytochemical analysis revealed that HSPB6 was present in the cytoplasm in the perinuclear region with some in the nucleus.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.06.022
      Issue No: Vol. 201 (2016)
  • Responses to thermal and salinity stress in wild and farmed Pacific
           oysters Crassostrea gigas
    • Authors: C.-Y. Yang; M.T. Sierp; C.A. Abbott; Yan Li; J.G. Qin
      Pages: 22 - 29
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): C.-Y. Yang, M.T. Sierp, C.A. Abbott, Yan Li, J.G. Qin
      The Pacific oyster Crassostrea gigas was introduced from Japan to many countries in the world for oyster farming, resulting in the establishment of wild populations in intertidal zones and resource competition with local faunas. This study examined physiological responses of wild oysters and farmed oysters to thermal (15°C, 25°C, 37°C and 44°C) and salinity stress (39, 50 and 60ppt). The wild oysters produced more 72kDa heat shock proteins when the temperature increased from 15°C to 25°C and 37°C and the salinity increased from 39 to 50 and 60ppt. However, the amount of 69kDa heat shock protein was similar between farmed and wild oysters when the temperature increased from 15°C to the sublethal temperature 37°C, but it was lower in wild oysters than in farmed oysters when the temperature increased from 15°C to the lethal temperature 44°C. In the tissues, wild oysters used more glycogen to promote metabolic activities by increasing the level of AEC (adenylate energy charge). The results suggest that farmed oysters might have limited ability to cope with heat stress due to low energy reserve and glycolysis activity for HSP synthesis. This study provides experimental evidence on differential responses between wild and farmed oysters to temperature and salinity changes, leading to a better understanding on the pattern of distribution for invading oyster species in the marine environment and the adaptation of marine invertebrates to the threat of climate change.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.06.024
      Issue No: Vol. 201 (2016)
  • Characterization of developmental Na+ uptake in rainbow trout larvae
           supports a significant role for Nhe3b
    • Authors: David Boyle; Salvatore D. Blair; Danuta Chamot; Greg G. Goss
      Pages: 30 - 36
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): David Boyle, Salvatore D. Blair, Danuta Chamot, Greg G. Goss
      Developing freshwater fish must compensate for the loss of ions, including sodium (Na+), to the environment. In this study, we used a radiotracer flux approach and pharmacological inhibitors to investigate the role of sodium/hydrogen exchange proteins (Nhe) in Na+ uptake in rainbow trout (Oncorhynchus mykiss) reared from fertilization in soft water (0.1mM Na+). For comparison, a second group of embryos/larvae reared in hard water (2.2mM Na+, higher pH and [Ca2+]) were also included in the experiment but were fluxed in soft water, only. Unidirectional rates of Na+ uptake increased throughout development and were significantly higher in embryos/larvae reared in soft water. However, the mechanisms of Na+ uptake in both groups of larvae were not significantly different, either in larvae immediately post-hatch or later in development: the broad spectrum Na+ channel blocker amiloride inhibited 85–90% of uptake and the Nhe-inhibitor EIPA also caused near maximal inhibitions of Na+ uptake. These data indicated Na+ uptake was Nhe-mediated in soft water. A role of Nhe3b (but not Nhe2 or Nhe3a) in Na+ uptake in soft water was also supported through gene expression analyses: expression of nhe3b increased throughout development in whole embryos/larvae in both groups and was significantly higher in those reared in soft water. This pattern of expression correlated well with measurements of Na+ uptake. Together these data indicate that in part, rainbow trout embryos/larvae reared in low Na+ soft water maintained Na+ homeostasis by an EIPA sensitive component of Na+ uptake, and support a primary role for Nhe3b.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.06.027
      Issue No: Vol. 201 (2016)
  • Identification of the major proteins present in the seminal plasma of
           European eel, and how hormonal treatment affects their evolution.
           Correlation with sperm quality
    • Authors: M. Carmen Vílchez; Davinia Pla; Víctor Gallego; Libia Sanz; Luz Pérez; Juan F. Asturiano; Juan J. Calvete; David S. Peñaranda
      Pages: 37 - 45
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): M. Carmen Vílchez, Davinia Pla, Víctor Gallego, Libia Sanz, Luz Pérez, Juan F. Asturiano, Juan J. Calvete, David S. Peñaranda

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.06.025
      Issue No: Vol. 201 (2016)
  • Circadian control of prothoracicotropic hormone release in an adult insect
           and the induction of its rhythmicity by light cues
    • Authors: Michael Cardinal-Aucoin; Colin G.H. Steel
      Pages: 46 - 52
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Michael Cardinal-Aucoin, Colin G.H. Steel
      The insect neuropeptide prothoracicotropic hormone (PTTH) is a critical regulator of larval development. We recently demonstrated that PTTH is also present in adult Rhodnius prolixus and is released by adult brains in vitro with a clear daily rhythm during egg development. Here, we employ a well-established in vitro bioassay, to show that the daily rhythm of PTTH release by brains in vitro is under circadian control since it persists in aperiodic conditions with a free running period of around 24h that is temperature compensated. Prolonged exposure (3weeks) of insects to continuous constant light (LL) completely eliminated PTTH release. Subsequent transfer of such insects from LL to constant darkness (DD) rapidly induced rhythmic PTTH release, indicating that the circadian rhythm of PTTH release is induced by photic cues. Western analysis identified PTTH in the adult hemolymph, suggesting that PTTH acts as a functional neurohormone in the adult insect. Dot blot analysis revealed that PTTH levels in the hemolymph also cycled with a daily rhythm that persisted in DD and was synchronous with the rhythm of PTTH release by brains in vitro. We conclude that the previously documented photosensitive clock in the brain regulates rhythmic PTTH release and thus generates the rhythm seen in the hemolymph. These results emphasize the importance of rhythmic PTTH release in the adult insect and support a role for PTTH in adult physiology and possibly within the adult circadian system.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.06.030
      Issue No: Vol. 201 (2016)
  • Calling rate, corticosterone plasma levels and immunocompetence of
           Hypsiboas albopunctatus
    • Authors: Stefanny Christie Monteiro Titon; Vania Regina de Assis; Braz Titon; Adriana Maria Giorgi Barsotti; Sarah Perry Flanagan; Fernando Ribeiro Gomes
      Pages: 53 - 60
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Stefanny Christie Monteiro Titon, Vania Regina de Assis, Braz Titon, Adriana Maria Giorgi Barsotti, Sarah Perry Flanagan, Fernando Ribeiro Gomes
      During the breeding season, male anuran amphibians produce advertisement calls. Androgens play a permissive role in the activation of calling activity, which is often positively correlated to androgen plasma levels and testes mass. Additionally, calling effort is also correlated to corticosterone plasma levels (hereinafter referred to as CORT), which is associated with the mobilization of energy substrates to sustain the high energy flux associated with this activity. However, high CORT also has many immunosuppressive effects and might interfere with reproduction. Consequently, CORT might mediate a compromise between reproductive effort and immunocompetence in anurans. In the present study, we investigated the relationship between calling rate, immunocompetence, and CORT in Hypsiboas albopunctatus, a midsize anuran occurring in South America. To understand these relationships, we conducted focal observations of calling behavior, followed by blood collection for CORT measurements and evaluation of some immune parameters. Our results showed that individuals with larger testes had higher calling rates, and those with higher calling rates showed lower cell-mediated immune response (swelling response to phytohaemagglutinin), although these relationships were not mediated by CORT. Furthermore, males calling early in the evening showed high CORT, and individuals with lower body condition index had higher CORT. We conclude that calling activity shows a cost in terms of cellular immune response in H. albopunctatus, but this compromise does not appear to be mediated by glucocorticoid plasma levels.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.06.023
      Issue No: Vol. 201 (2016)
  • Are mussels able to distinguish underwater sounds' Assessment of the
           reactions of Mytilus galloprovincialis after exposure to lab-generated
           acoustic signals
    • Authors: Mirella Vazzana; Monica Celi; Giulia Maricchiolo; Lucrezia Genovese; Valentina Corrias; Enza Maria Quinci; Giovanni de Vincenzi; Vincenzo Maccarrone; Gaetano Cammilleri; Salvatore Mazzola; Giuseppa Buscaino; Francesco Filiciotto
      Pages: 61 - 70
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Mirella Vazzana, Monica Celi, Giulia Maricchiolo, Lucrezia Genovese, Valentina Corrias, Enza Maria Quinci, Giovanni de Vincenzi, Vincenzo Maccarrone, Gaetano Cammilleri, Salvatore Mazzola, Giuseppa Buscaino, Francesco Filiciotto
      This study examined the effects of lab-generated acoustic signals on the behaviour and biochemistry of Mediterranean mussels (Mytilus galloprovincialis). The experiment was carried out in a tank equipped with a video-recording system using six groups of five mussels exposed to five acoustic treatments (each treatment was replicated three times) for 30min. The acoustic signals, with a maximum sound pressure level of 150dB rms re 1μPa, differed in frequency range as follows: low (0.1–5kHz), mid-low (5–10kHz), mid (10–20kHz), mid-high (20–40kHz) and high (40–60kHz). The exposure to sweeps did not produce any significant changes in the mussels' behaviour. Conversely, the specimens exposed to the low frequency band treatment showed significantly higher values of the following biochemical stress parameters measured in their plasma and tissues: glucose, total proteins, total haemocyte number (THC), heat shock protein 70 (Hsp70) expression, and Acetylcholinesterase (AChE) activity. The responses observed in the mussels exposed to low frequency sweeps enable us to suppose a biological and ecological role for this sound, which contains the main frequencies produced by both shipping traffic and the acoustic emissions of fish.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.06.029
      Issue No: Vol. 201 (2016)
  • Effects of random food deprivation and refeeding on energy metabolism,
           behavior and hypothalamic neuropeptide expression in Apodemus chevrieri
    • Authors: Zhu Wan-long; Wang Zheng-kun
      Pages: 71 - 78
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Zhu Wan-long, Wang Zheng-kun
      Maintaining adaptive control of behavior and physiology is the main strategy used by animals in responding to changes of food resources. To investigate the effects of random food deprivation (FD) and refeeding on energy metabolism and behavior in Apodemus chevrieri, we acclimated adult males to FD for 4weeks, then refed them ad libitum for 4weeks (FD-Re group). During the period of FD, animals were fed ad libitum for 4 randomly assigned days each week, and deprived of food the other 3days. A control group was fed ad libitum for 8weeks. At 4 and 8weeks we measured body mass, thermogenesis, serum leptin levels, body composition, gastrointestinal tract morphology, behavior and hypothalamic neuropeptide expression. At 4weeks, food intake, gastrointestinal mass, neuropeptide Y (NPY) and agouti-related protein (AgRP) mRNA expressions increased and thermogenesis, leptin levels, pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) expressions decreased in FD compared with controls. FD also showed more resting behavior and less activity than the controls on ad libitum day. There were no differences between FD-Re and controls at 8weeks, indicating significant plasticity. These results suggested that animals can compensate for unpredictable reduction in food availability by increasing food intake and reducing energy expended through thermogenesis and activity. Leptin levels, NPY, AgRP, POMC, and CART mRNA levels may also regulate energy metabolism. Significant plasticity in energy metabolism and behavior was shown by A. chevrieri over a short timescale, allowing them to adapt to food shortages in nutritionally unpredictable environments.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.06.034
      Issue No: Vol. 201 (2016)
  • Defining the allometric relationship between size and individual fatty
           acid turnover in barramundi Lates calcarifer
    • Authors: Michael J. Salini; David Poppi; Giovanni M. Turchini; Brett D. Glencross
      Pages: 79 - 86
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Michael J. Salini, David Poppi, Giovanni M. Turchini, Brett D. Glencross
      An experiment was conducted with barramundi (Asian seabass; Lates calcarifer) to examine the allometric scaling effect of individual fatty acids. Six treatment size classes of fish were deprived of food for 21days (Treatment A, 10.5±0.13g; Treatment B, 19.2±0.11g; Treatment C, 28.3±0.05g; Treatment D, 122.4±0.10g; Treatment E, 217.6±0.36g; Treatment F, 443.7±1.48g; mean±SD) with each treatment comprising of fifteen fish, in triplicate. The assessment of somatic losses of whole-body energy and lipid were consistent with previous studies, validating the methodology to be extended to individual fatty acids. Live-weight (LW) exponent values were determined to be 0.817±0.010 for energy and 0.895±0.007 for lipid. There were significant differences among the fatty acids ranging from 0.687±0.005 for 20:5n-3 (eicosapentaenoic acid) and 0.954±0.008 for 18:1n-9 (oleic acid). The LW exponent values were applied to existing fatty acid intake and deposition data of barramundi fed with either 100% fish oil or 100% poultry oil. From this the maintenance requirement for each fatty acid was determined. The metabolic demands for maintenance and growth were then iteratively determined for fish over a range of size classes. Application of these exponent values to varying levels of fatty acid intake demonstrated that the biggest driver in the utilisation of fatty acids in this species is deposition demand and despite their reputed importance, the long-chain polyunsaturated fatty acids had nominal to no maintenance requirement.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.06.028
      Issue No: Vol. 201 (2016)
  • Hypoxia-reoxygenation differentially alters the thermal sensitivity of
           complex I basal and maximal mitochondrial oxidative capacity
    • Authors: John O. Onukwufor; Fred Kibenge; Don Stevens; Collins Kamunde
      Pages: 87 - 94
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): John O. Onukwufor, Fred Kibenge, Don Stevens, Collins Kamunde
      Hypoxia-reoxygenation (H-R) transitions and temperature fluctuations occur frequently in biological systems and likely interact to alter cell function. To test how H-R modulates mitochondrial function at different temperatures we measured the effects of H-R on isolated fish liver mitochondrial oxidation rates over a wide temperature range (5–25°C). Subsequently, the mechanisms underlying H-R induced mitochondrial responses were examined. H-R inhibited the complex I (CI) maximal (state 3) and stimulated the basal (state 4) mitochondrial oxidation rates with temperature enhancing both effects. As a result, the thermal sensitivity (Q10) for CI maximal respiration was reduced while that for basal respiration was increased by H-R. H-R reduced both the coupling and phosphorylation efficiencies more profoundly at high temperature suggesting that mitochondria were more resistant to H-R at low temperature. The H-R induced mitochondrial impairments were associated with increased reactive oxygen species (ROS) production and proton leak, dissipation of membrane potential, and loss of structural integrity of the organelles. Overall, our study provides insight into the mechanisms of H-R induced mitochondrial morphofunctional disruption and shows that the moderation of effects of H-R on oxidative phosphorylation by temperature depends on the functional state.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.06.033
      Issue No: Vol. 201 (2016)
  • ATP-consuming processes in hepatocytes of river lamprey Lampetra
           fluviatilis on the course of prespawning starvation
    • Authors: Natalia I. Agalakova; Irina V. Brailovskaya; Svetlana A. Konovalova; Sergei M. Korotkov; Elena A. Lavrova; Anatolii A. Nikiforov
      Pages: 95 - 100
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Natalia I. Agalakova, Irina V. Brailovskaya, Svetlana A. Konovalova, Sergei M. Korotkov, Elena A. Lavrova, Anatolii A. Nikiforov
      The work was performed to establish which of the major ATP-consuming processes is the most important for surviving of hepatocytes of female lampreys on the course of prespawning starvation. The requirements of protein synthesis and Na+-K+-ATPase for ATP in the cells were monitored by the changes in mitochondrial membrane potential (MMP) in the presence of corresponding inhibitors from the peak of metabolic depression (January–February) to the time of recovery from it (March–April) and spawning (May). Integrity of lamprey liver cells was estimated by catalytic activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in blood plasma. In January–February, the share of ATP necessary for protein synthesis was 20–22%, whereas before spawning it decreased to 8–11%. Functioning of Na+-K+-pump required 22% of cellular ATP at the peak of metabolic depression, but 38% and 62% of ATP in March–April and May, respectively. Progression of prespawning period was accompanied by 3.75- and 1.6-fold rise of ALT and AST activities in blood plasma, respectively, whereas de Ritis coefficient decreased from 2.51±0.34 to 0.81±0.08, what indicates severe damage of hepatocyte membranes. Thus, the adaptive strategy of lamprey hepatocytes to develop metabolic depression under conditions of energy limitation is the selective production of proteins necessary for spawning, most probably vitellogenins. As spawning approaches, the maintenance of transmembrane ion gradients, membrane potential and cell volume to prevent premature cell death becomes the priority cell function.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.07.002
      Issue No: Vol. 201 (2016)
  • Predicting transport survival of brindle and red rock lobsters Jasus
           edwardsii using haemolymph biochemistry and behaviour traits
    • Authors: Cedric J. Simon; Tania C. Mendo; Bridget S. Green; Caleb Gardner
      Pages: 101 - 109
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Cedric J. Simon, Tania C. Mendo, Bridget S. Green, Caleb Gardner
      Mortality events during live transport of Jasus edwardsii rock lobsters are common around the time of season openings in Tasmania, with lobsters from deeper fishing areas with pale shell colouration (brindle) being perceived as more susceptible than shallow-water, red-coloured (red) lobsters. The aims of this study were to assess and predict the vulnerability of brindle and red lobsters to extended emersion exposure using pre- and post-emersion data which included 28 haemolymph biochemical parameters and 5 behaviour traits. No effect of lobster shell colour on haemolymph biochemistry, behaviour traits and their vulnerability to emersion was found. A combined survival of 97% after 40h and 57% after 64h in a first experiment, and 37% after 64h in a second experiment, was observed. Behaviour traits (i.e., righting response, tail flips and three reflex behaviours) were poor indicator of survival. Haemolymph parameters were either unaffected by emersion (e.g., Brix index, protein and lipids), affected by emersion but not associated with mortality (e.g., total haemocyte counts, calcium, magnesium, bicarbonate, glucose and uric acid), or associated with mortality following a recovery period (e.g., pH, the sodium to potassium ratio, urea, and the activity of amylase). A build-up of anaerobic end-products and nitrogenous waste most likely resulted in the mortality. A model based on lobster size and the pre-emersion concentration of haemolymph bicarbonate and haemocyanin was found to be a useful indicator of future survival. This study provides promising leads towards the development of a blood based vulnerability test for live crustacean prior transport.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.07.001
      Issue No: Vol. 201 (2016)
  • Combined effects of dietary polyunsaturated fatty acids and parasite
           exposure on eicosanoid-related gene expression in an invertebrate model
    • Authors: Nina Schlotz; Anne Roulin; Dieter Ebert; Dominik Martin-Creuzburg
      Pages: 115 - 123
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Nina Schlotz, Anne Roulin, Dieter Ebert, Dominik Martin-Creuzburg
      Eicosanoids derive from essential polyunsaturated fatty acids (PUFA) and play crucial roles in immunity, development, and reproduction. However, potential links between dietary PUFA supply and eicosanoid biosynthesis are poorly understood, especially in invertebrates. Using Daphnia magna and its bacterial parasite Pasteuria ramosa as model system, we studied the expression of genes coding for key enzymes in eicosanoid biosynthesis and of genes related to oogenesis in response to dietary arachidonic acid and eicosapentaenoic acid in parasite-exposed and non-exposed animals. Gene expression related to cyclooxygenase activity was especially responsive to the dietary PUFA supply and parasite challenge, indicating a role for prostanoid eicosanoids in immunity and reproduction. Vitellogenin gene expression was induced upon parasite exposure in all food treatments, suggesting infection-related interference with the host's reproductive system. Our findings highlight the potential of dietary PUFA to modulate the expression of key enzymes involved in eicosanoid biosynthesis and reproduction and thus underpin the idea that the dietary PUFA supply can influence invertebrate immune functions and host-parasite interactions.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.07.008
      Issue No: Vol. 201 (2016)
  • Volume regulation of intestinal cells of echinoderms: Putative role of ion
           transporters (Na+/K+-ATPase and NKCC)
    • Authors: Giovanna C. Castellano; Marta M. Souza; Carolina A. Freire
      Pages: 124 - 131
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Giovanna C. Castellano, Marta M. Souza, Carolina A. Freire
      Echinoderms are exclusively marine osmoconformer invertebrates. Some species occupy the challenging intertidal region. Upon salinity changes, the extracellular osmotic concentration of these animals also varies, exposing tissues and cells to osmotic challenges. Cells and tissues may then respond with volume regulation mechanisms, which involve transport of ions and water into and/or out of the cells, through ion transporters, such as the Na+/K+-ATPase and NKCC. The goal of this study was to relate the cell volume regulation capacity of echinoderm intestinal cells Na+/K+-ATPase and NKCC activities, in three echinoderm species: Holothuria grisea, Arbacia lixula, and Echinometra lucunter. Isolated cells of these species displayed some control of their cell volume upon exposure to anisosmotic media (isolated intestinal cells, calcein fluorescence as indicator of volume change), with a distinct higher capacity shown by H. grisea, which did not swell even upon 50% hyposmotic shock. The holothuroid cells showed indirect evidence (effect of furosemide) of the participation of NKCC in this process, with a secretory function, and of a secondary role by the NKA (effect of ouabain). Other mechanisms are probably responsible for this function in the urchins. Variable expression of these transporters, and others not examined here, may to some extent account for the variability in cell volume regulation capacity in echinoderm cells.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.07.006
      Issue No: Vol. 201 (2016)
  • Regulation of sex steroid production and mRNAs encoding gonadotropin
           receptors and steroidogenic proteins by gonadotropins, cyclic AMP and
           insulin-like growth factor-I in ovarian follicles of rainbow trout
           (Oncorhynchus mykiss) at two stages of vitellogenesis
    • Authors: Ikumi Nakamura; Makoto Kusakabe; Penny Swanson; Graham Young
      Pages: 132 - 140
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Ikumi Nakamura, Makoto Kusakabe, Penny Swanson, Graham Young
      At the completion of vitellogenesis, the steroid biosynthetic pathway in teleost ovarian follicles switches from estradiol-17β (E2) to maturational progestin production, associated with decreased follicle stimulating hormone (Fsh) and increased luteinizing hormone (Lh) signaling. This study compared effects of gonadotropins, human insulin-like growth factor-I (IGF1), and cAMP/protein kinase A signaling (forskolin) on E2 production and levels of mRNAs encoding steroidogenic proteins and gonadotropin receptors using midvitellogenic (MV) and late/postvitellogenic (L/PV) ovarian follicles of rainbow trout. Fsh, Lh and forskolin, but not IGF1, increased testosterone and E2 production in MV and L/PV follicles. Fsh increased steroidogenic acute regulatory protein (star; MV), 3β-hydroxysteroid dehydrogenase/Δ 5−4 isomerase (hsd3b; MV) and P450 aromatase (cyp19a1a; MV) transcript levels. Lh increased star mRNA levels (MV, L/PV) but reduced cyp19a1a transcripts in L/PV follicles. At both follicle stages, IGF1 reduced levels of hsd3b transcripts. In MV follicles, IGF1 decreased P450 side-chain cleavage enzyme (cyp11a1) transcripts but increased cyp19a1a transcripts. In MV follicles only, forskolin increased star and hsd3b transcripts. Forskolin reduced MV follicle cyp11a1 transcripts and reduced cyp19a1a transcripts in follicles at both stages. Fsh and Lh reduced fshr transcripts in L/PV follicles. Lh also reduced lhcgr transcripts (L/PV). IGF1 had no effect on gonadotropin receptor transcripts. Forskolin reduced MV follicle fshr transcript levels and reduced lhcgr transcripts in L/PV follicles. These results reveal hormone- and stage-specific transcriptional regulation of steroidogenic protein and gonadotropin receptor genes and suggest that the steroidogenic shift at the completion of vitellogenesis involves loss of stimulatory effects of Fsh and Igfs on cyp19a1a expression and inhibition of cyp19a1a transcription by Lh.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.06.035
      Issue No: Vol. 201 (2016)
  • High glucose impairs acetylcholine-mediated vasodilation in isolated
           arteries from Mourning doves (Z. macroura)
    • Authors: Catherine L. Jarrett; Zoha Ahmed; James J. Faust; Karen L. Sweazea
      Pages: 141 - 145
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Catherine L. Jarrett, Zoha Ahmed, James J. Faust, Karen L. Sweazea
      Normal avian plasma glucose levels are 1.5–2 times greater than mammals of similar size. In mammals, hyperglycemia induces oxidative stress and impaired endothelium-dependent vasodilation. Prior work has shown that mourning doves have high levels of antioxidants and isolated vessels have low endogenous oxidative stress. Therefore, the hypothesis was that endothelium-dependent vasodilation of isolated avian arteries would not be impaired following acute exposure to high glucose. Isolated small resistance cranial tibial arteries (c. tibial) were cannulated and pressurized in a vessel chamber then incubated with either normal or high glucose (20mM vs. 30mM) for 1h at 41°C. Vessels were then pre-constricted to 50% of resting inner diameter with phenylephrine (PE) followed by increasing doses of acetylcholine (ACh; 10−9 to 10−5 M, 5min per step). Percent vasodilation was measured by tracking the inner diameter with edge-detection software. Contrary to our hypothesis, ACh-induced vasodilation was impaired with acute exposure to high glucose (p=0.013). The impairment was not related to increased osmolarity since vasodilation of arteries exposed to an equimolar combination of 20mM d-glucose and 10mM l-glucose was not different from controls (p=0.273). Rather, the impaired vasodilation was attributed to oxidative stress since superoxide levels were elevated 168±42% (p=0.02) and pre-exposure of arteries to the superoxide dismutase mimetic tiron (10mM) improved vasodilation (p<0.05). Therefore, isolated arteries from doves do not have endogenous mechanisms to prevent impaired vasodilation resulting from high glucose-mediated increases in oxidative stress.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.07.010
      Issue No: Vol. 201 (2016)
  • A fatty acyl desaturase (fads2) with dual Δ6 and Δ5 activities from the
           freshwater carnivorous striped snakehead Channa striata
    • Authors: Meng-Kiat Kuah; Annette Jaya-Ram; Alexander Chong Shu-Chien
      Pages: 146 - 155
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Meng-Kiat Kuah, Annette Jaya-Ram, Alexander Chong Shu-Chien
      There is a lack of understanding on how the environment and trophic niche affect the capability of long-chain polyunsaturated fatty acids (LC-PUFA) in freshwater carnivorous teleost. In this present study, we isolated and functionally characterised a fatty acyl desaturase (Fads) from the striped snakehead Channa striata. Sequence comparison and phylogenetic analysis suggested a Fads2 protein that is closely related to previously characterised Fads2 proteins from freshwater carnivorous and marine herbivorous fish species. We further demonstrated the capacity of Δ6 and Δ5 desaturation activities for this particular desaturase, with highest activities towards the conversion of omega-3 (n-3) polyunsaturated fatty acids (PUFA). Low Δ4 desaturation activity was also detected, although the significance of this at a physiological level remains to be studied. The expression of this striped snakehead Δ6/Δ5 fads2 gene was highest in brain, followed by liver and intestine. In liver, diet fortified with high LC-PUFA concentration impeded the expression of Δ6/Δ5 fads2 gene compared to vegetable oil (VO) based diets. The discovery of Δ6/Δ5 Fads2 desaturase here complements the previous discovery of a Δ4 Fads2 desaturase and an Elovl5 elongase, lending proof to the existence of all the required enzymatic machinery to biosynthesise LC-PUFA from C18 PUFA in a freshwater carnivorous species.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.07.007
      Issue No: Vol. 201 (2016)
  • Acute hyperthermic responses of heat shock protein and estrogen receptor
           mRNAs in rainbow trout hepatocytes
    • Authors: Yudong Jia; Timothy D. Cavileer; James J. Nagler
      Pages: 156 - 161
      Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Yudong Jia, Timothy D. Cavileer, James J. Nagler
      Heat shock proteins (HSPs) are induced upon elevated temperature in fishes. HSPs also function as molecular chaperones for cellular proteins, including steroid hormone receptors. Estrogen receptors (ERs) are critical for the hormone signaling necessary during the liver production of the yolk precursor protein vitellogenin in oviparous vertebrates. Considering the possible regulatory role of HSPs on the ER signaling pathway, the present study characterized the mRNA expression of all known isoforms of HSP70 (hsp70a, hsp70b), HSP90 (hsp90a1a, hsp90a1b, hsp90a2a, hsp90a2b, hsp90b1, hsp90b2), and ERs (erα1, erα2, erβ1, erβ2) in Rainbow Trout hepatocytes following an acute heat shock (1h at 25°C) compared to a control treatment (12°C). The results showed that the mRNA levels of hsp70a, hsp70b, hsp90a1b, hsp90a2a, and hsp90b2 were significantly increased after heat shock, while erα1 mRNA levels were significantly reduced by this treatment. hsp90a1a, hsp90a2b, hsp90b1, erα2, erβ1 and erβ2 were unaffected by this acute hyperthermic treatment. Comparatively, the responses of the two hsp70 isoforms were much greater than the hsp90 isoforms. Acute heat shock treatment of hepatocytes followed by a 24h exposure to 17β-estradiol (E2) exposure also resulted in decreased expression of erα1 mRNA, but not vitellogenin (vtg) mRNA. This study showed that some hsp70 and hsp90 isoforms display a robust response to an acute hyperthermic treatment in Rainbow Trout hepatocytes. Among the transcripts measured here, the erα1 isoform uniquely showed significantly decreased mRNA levels upon acute heat treatment.

      PubDate: 2016-08-03T10:43:25Z
      DOI: 10.1016/j.cbpa.2016.04.023
      Issue No: Vol. 201 (2016)
  • Appetite regulating factors in pacu (Piaractus mesopotamicus): Tissue
           distribution and effects of food quantity and quality on gene expression
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Hélène Volkoff, Rafael Esatevan Sabioni, Luiz Lehmann Coutinho, José Eurico Possebon Cyrino
      The pacu Piaractus mesopotamicus is an omnivorous fish considered a promising species for aquaculture. Little is known about the endocrine regulation of feeding in this species. In this study, transcripts for orexin, cocaine and amphetamine regulated transcript (CART), cholecystokinin (CCK) and leptin were isolated in pacu. Orexin, CCK and leptin have widespread mRNA distributions in brain and periphery, CART is limited to the brain. To examine the role of these peptides in the regulation of feeding and energy status, mRNA expression levels were compared between fed and fasted fish and around feeding time. Both orexin and CART brain expressions were affected by fasting and displayed periprandial changes, suggesting a role in both short- and long-term regulation of feeding. CCK intestinal expression decreased in fasted fish and displayed periprandial changes, suggesting CCK acts as a peripheral satiety factor. Leptin was not affected by fasting but displayed periprandial changes, suggesting a role as a short-term regulator. To examine if these peptides are affected by diet, brain and gut expressions were assessed in fish fed with different diets containing soy protein concentrate. Food intake, weight gain and expressions of orexin, CART, CCK and leptin were little affected by replacement of fish protein with soy protein, suggesting that pacu is able to tolerate and grow well with a diet rich in plant material. Overall, our results suggest that orexin, CART, CCK and leptin are involved in the physiology of feeding of pacu and that their expressions are little affected by plant-based diets.

      PubDate: 2016-10-16T05:19:28Z
  • Nonphotic entrainment in fish
    • Authors: Jose
      Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Jose F. López-Olmeda
      Organisms that live on the Earth are subjected to environmental variables that display cyclic variations, such as light, temperature and tides. Since these cyclic changes in the environment are constant and predictable, they have affected biological evolution through selecting the occurrence of biological rhythms in the physiology of all living organisms, from prokaryotes to mammals. Biological clocks confer organisms an adaptive advantage as they can synchronize their behavioral and physiological processes to occur at a given moment of time when effectiveness and success would be greater and/or the cost and risk for organisms would be lower. Among environmental synchronizers, light has been mostly widely studied to date. However, other environmental signals play an important role in biological rhythms, especially in aquatic animals like fish. This review focuses on current knowledge about the role of nonphotic synchronizers (temperature, food and tidal cycles) on biological rhythms in fish, and on the entrainment of the fish circadian system to these synchronizers.

      PubDate: 2016-09-21T01:27:29Z
  • Vibrational sensitivity of the subgenual organ complex in female
           Sipyloidea sipylus stick insects in different experimental paradigms of
           stimulus direction, leg attachment, and ablation of a connective tibial
           sense organ
    • Authors: Johannes Reinhard; Lakes-Harlan
      Abstract: Publication date: Available online 7 September 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Johannes Strauß, Reinhard Lakes-Harlan
      We document the sensitivity to sinusoidal vibrations for chordotonal organs in the stick insect tibia (Sipyloidea sipylus). In the tibia, the scolopidial subgenual organ (~40 scolopidial sensilla), distal organ (~20 scolopidial sensilla), and distal tibial chordotonal organ (~7 scolopidial sensilla) are present. We study the sensitivity of tibial sensory organs in all leg pairs to vibration stimuli as sensory thresholds by recording summed action potentials from Nervus cruris in the femur. The tibia was stimulated with a minishaker delivering vibrational stimuli. Because different experimental procedures may affect the vibration sensitivity, we here analysed possible effects of different experimental conditions: (1) the stimulus direction delivered in either horizontal or vertical direction to the leg; (2) recording responses only from the subgenual organ complex after ablation of the distal tibial chordotonal organ, and (3) the attachment of the leg to the minishaker by plastilin, beeswax-colophony, or freely standing legs. The tibial scolopidial organs give summed responses to vibration stimuli with highest sensitivity between 500 and 1000Hz for all leg pairs. In the different experimental series, we find that (1) thresholds were influenced by stimulation direction with lower thresholds in response to vertical vibrations, (2) ablating the distal tibial chordotonal organ by cutting the distal-most tibia did not change the summed sensory thresholds significantly, and (3) the attachment material between legs and the minishaker (plastilin or beeswax-colophony mixture) did not significant influence the sensory thresholds against free-standing tarsi. The distal tibial chordotonal organ is a connective chordotonal organ attached to a tendon and is likely a proprioceptive organ. These results emphasise that vibrational thresholds are mainly direction-sensitive. Thus, the direction of stimulus delivery during electrophysiological recordings is relevant for comparisons of vibratory sensory thresholds.

      PubDate: 2016-09-10T15:33:25Z
  • Characterization of the peripheral thyroid system of gilthead seabream
           acclimated to different ambient salinities
    • Authors: Ruiz-Jarabo P.H.M.; Klaren Louro J.A. Martos-Sitcha P.I.S. Pinto Vargas-Chacoff Flik
      Abstract: Publication date: Available online 21 August 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): I. Ruiz-Jarabo, P.H.M. Klaren, B. Louro, J.A. Martos-Sitcha, P.I.S. Pinto, L. Vargas-Chacoff, G. Flik, G. Martinez-Rodriguez, D.M. Power, J.M. Mancera, F.J. Arjona
      Thyroid hormones are involved in many developmental and physiological processes, including osmoregulation. The regulation of the thyroid system by environmental salinity in the euryhaline gilthead seabream (Sparus aurata) is still poorly characterized. To this end seabreams were exposed to four different environmental salinities (5, 15, 40 and 55ppt) for 14days, and plasma free thyroid hormones (fT3, fT4), outer ring deiodination and Na+/K+-ATPase activities in gills and kidney, as well as other osmoregulatory and metabolic parameters were measured. Low salinity conditions (5ppt) elicited a significant increase in fT3 (29%) and fT4 (184%) plasma concentrations compared to control animals (acclimated to 40ppt, natural salinity conditions in the Bay of Cádiz, Spain), while the amount of pituitary thyroid stimulating hormone subunit β (tshb) transcript abundance remained unchanged. In addition, plasma fT4 levels were positively correlated to renal and branchial deiodinase type 2 (dio2) mRNA expression. Gill and kidney T4-outer ring deiodination activities correlated positively with dio2 mRNA expression and the highest values were observed in fish acclimated to low salinities (5 and 15ppt). The high salinity (55ppt) exposure caused a significant increase in tshb expression (65%), but deiodinase gene expression (dio1 and dio2) and activity did not change and were similar to controls (40ppt). In conclusion, acclimation to different salinities led to changes in the peripheral regulation of thyroid hormone metabolism in seabream. Therefore, thyroid hormones are involved in the regulation of ion transport and osmoregulatory physiology in this species. The conclusions derived from this study may also allow aquaculturists to modulate thyroid metabolism in seabream by adjusting culture salinity.

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

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

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

      PubDate: 2016-08-17T12:40:02Z
  • Variation in winter metabolic reduction between sympatric amphibians
    • Abstract: Publication date: November 2016
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 201
      Author(s): Luděk Podhajský, Lumír Gvoždík
      Distribution and abundance of temperate ectotherms is determined, in part, by the depletion of their limited caloric reserves during wintering. The magnitude of winter energy drain depends on the species-specific capacity to seasonally modify the minimal maintenance costs. We examined seasonal variation of minimum oxygen consumption between two newt species, Ichthyosaura alpestris and Lissotriton vulgaris. Oxygen consumption was measured in both species during their active season (daily temperature range=12–22°C) and wintering period (4°C) at 4°C and 8°C. The seasonal reduction in metabolic rates differed between species and experimental temperatures. Wintering newts reduced their metabolic rates at 4°C and 8°C in I. alpestris, but only at 8°C in L. vulgaris. Both species reduced the thermal sensitivity of oxygen consumption during wintering. Theoretical calculations of winter depletion of caloric reserves under various thermal conditions revealed that seasonal metabolic reduction is more effective in I. alpestris than in L. vulgaris, and its effectiveness will increase with the proportion of warmer days during wintering period. The variation in winter metabolic reduction between sympatric newt species potentially contributes to their distribution patterns and population dynamics under climate change.

      PubDate: 2016-08-03T10:43:25Z
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