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AAPS PharmSciTech     Hybrid Journal   (Followers: 6)
Acetic Acid Bacteria     Open Access   (Followers: 1)
ACS Central Science     Open Access   (Followers: 5)
ACS Chemical Biology     Full-text available via subscription   (Followers: 193)
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: 16)
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: 63)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 13)
American Journal of Polymer Science     Open Access   (Followers: 23)
Amino Acids     Hybrid Journal   (Followers: 8)
Analytical Biochemistry     Hybrid Journal   (Followers: 143)
Angiogenesis     Hybrid Journal   (Followers: 3)
Annals of Clinical Biochemistry     Hybrid Journal   (Followers: 8)
Annual Review of Biochemistry     Full-text available via subscription   (Followers: 52)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 10)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 45)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 17)
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: 14)
Biochemical Genetics     Hybrid Journal   (Followers: 3)
Biochemical Journal     Full-text available via subscription   (Followers: 26)
Biochemical Pharmacology     Hybrid Journal   (Followers: 8)
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: 241)
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: 2)
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: 25)
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: 45)
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: 22)
Chemical Engineering Journal     Hybrid Journal   (Followers: 30)
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: 61)
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: 10)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Current Chemical Biology     Hybrid Journal   (Followers: 2)
Current Medicinal Chemistry     Hybrid Journal   (Followers: 15)
Current Opinion in Chemical Biology     Hybrid Journal   (Followers: 24)
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: 59)
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: 6)
International Journal of Food Contamination     Open Access  
International Journal of Plant Physiology and Biochemistry     Open Access  
International Journal of Plant Research     Open Access   (Followers: 3)
International Journal of Secondary Metabolite     Open Access   (Followers: 1)
Invertebrate Immunity     Open Access   (Followers: 1)
JBIC Journal of Biological Inorganic Chemistry     Hybrid Journal   (Followers: 5)
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: 44)
Journal of Biological Chemistry     Full-text available via subscription   (Followers: 179)
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: 5)
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: 23)
Journal of Photochemistry and Photobiology B: Biology     Hybrid Journal   (Followers: 3)
Journal of Physiobiochemical Metabolism     Hybrid Journal   (Followers: 1)
Journal of Physiology and Biochemistry     Hybrid Journal   (Followers: 3)
Journal of Plant Biochemistry and Biotechnology     Hybrid Journal   (Followers: 5)
Journal of Steroid Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 2)
Journal of Virology & Antiviral Research     Hybrid Journal   (Followers: 3)
Journal of Wood Chemistry and Technology     Hybrid Journal   (Followers: 7)
La Rivista Italiana della Medicina di Laboratorio - Italian Journal of Laboratory Medicine     Hybrid Journal  
Lab on a Chip     Full-text available via subscription   (Followers: 34)
Marine Chemistry     Hybrid Journal   (Followers: 6)
Methods in Enzymology     Full-text available via subscription   (Followers: 11)
Molecular and Biochemical Parasitology     Hybrid Journal   (Followers: 2)
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: 5)
Natural Products and Bioprospecting     Open Access   (Followers: 3)
Nature Chemical Biology     Full-text available via subscription   (Followers: 69)
Nature Communications     Open Access   (Followers: 123)
Neurosignals     Open Access  
Novelty in Biomedicine     Open Access  
Ocean Acidification     Open Access   (Followers: 3)
Organic & Biomolecular Chemistry     Full-text available via subscription   (Followers: 86)
Peptidomics     Open Access  
Pesticide Biochemistry and Physiology     Hybrid Journal   (Followers: 4)
Pflugers Archiv European Journal of Physiology     Hybrid Journal   (Followers: 3)
Pharmaceutical Bioprocessing     Full-text available via subscription   (Followers: 1)
Pharmacognosy Magazine     Open Access   (Followers: 2)

        1 2     

Journal Cover Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
  [SJR: 0.939]   [H-I: 84]   [5 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1095-6433
   Published by Elsevier Homepage  [3039 journals]
  • 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)
  • Modulation of the heat shock response is associated with acclimation to
           novel temperatures but not adaptation to climatic variation in the ants
           Aphaenogaster picea and A. rudis
    • Abstract: Publication date: February 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 204
      Author(s): Sara Helms Cahan, Andrew D. Nguyen, John Stanton-Geddes, Clint A. Penick, Yainna Hernáiz-Hernández, Bernice B. DeMarco, Nicholas J. Gotelli
      Ecological diversification into thermally divergent habitats can push species toward their physiological limits, requiring them to accommodate temperature extremes through plastic or evolutionary changes that increase persistence under the local thermal regime. One way to withstand thermal stress is to increase production of heat shock proteins, either by maintaining higher baseline abundance within cells or by increasing the magnitude of induction in response to heat stress. We evaluated whether environmental variation was associated with expression of three heat shock protein genes in two closely-related species of woodland ant, Aphaenogaster picea and A. rudis. We compared adult workers from colonies collected from 25 sites across their geographic ranges. Colonies were maintained at two different laboratory temperatures, and tested for the independent effects of environment, phylogeny, and acclimation temperature on baseline and heat-induced gene expression. The annual maximum temperature at each collection site (Tmax) was not a significant predictor of either baseline expression or magnitude of induction of any of the heat shock protein genes tested. A phylogenetic effect was detected only for basal expression of Hsp40, which was lower in the most southern populations of A. rudis and higher in a mid-range population of possible hybrid ancestry. In contrast, a higher acclimation temperature significantly increased baseline expression of Hsc70-4, and increased induction of Hsp40 and Hsp83. Thus, physiological acclimation to temperature variation appears to involve modulation of the heat shock response, whereas other mechanisms are likely to be responsible for evolutionary shifts in thermal performance associated with large-scale climate gradients.

      PubDate: 2016-11-30T09:28:34Z
  • Comparing biomarker responses during thermal acclimation: A lethal vs
           non-lethal approach in a tropical reef clownfish
    • Abstract: Publication date: February 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 204
      Author(s): Carolina Madeira, Diana Madeira, Mário S. Diniz, Henrique N. Cabral, Catarina Vinagre
      Knowledge of thermal stress biology for most tropical fish species in reef ecosystems under climate change is still quite limited. Thus, the objective of this study was to measure the time-course changes of thermal stress biomarkers in the commercially exploited coral reef fish Amphiprion ocellaris, during a laboratory simulated event of increased temperature. Heat shock protein 70kDa (Hsp70) and total ubiquitin (Ub) were determined in the muscle (lethal method) and in the fin (non-lethal alternative method) under two temperature treatments (control – 26°C and elevated temperature – 30°C) throughout one month with weekly samplings. Results suggest that biomarker basal levels are tissue-specific and influence the degree of response under temperature exposure. Responses were highly inducible in the muscle but not in fin tissue, indicating that the latter is not reliable for monitoring purposes. Thermal stress was observed in the muscle after one week of exposure (both biomarkers increased significantly) and Ub levels then decreased, suggesting the animals were able to acclimate by maintaining high levels of Hsp70 and through an effective protein turnover. In addition, the results show that mortality rates did not differ between treatments. This indicates that A. ocellaris is capable of displaying a plastic response to elevated temperature by adjusting the protein quality control system to protect cell functions, without decreasing survival. Thus, this coral reef fish species presents a significant acclimation potential under ocean warming scenarios of +4°C. Monitoring of thermal stress through a non-lethal method, fin-clipping, although desirable proved to be inadequate for this species.

      PubDate: 2016-11-30T09:28:34Z
  • Milk composition of free-ranging red hartebeest, giraffe, Southern
           reedbuck and warthog and a phylogenetic comparison of the milk of African
    • Abstract: Publication date: February 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 204
      Author(s): G. Osthoff, A. Hugo, M. Madende, F. Deacon, P.J. Nel
      The composition of major nutrients and fatty acids of the milk of three species, red hartebeest, Southern reedbuck and warthog, and milk fatty acids of giraffe, that have not been published before, are reported, and together with the same parameters of 11 species previously published, were incorporated in a phylogenetic comparison. Unique properties of milk composition have been observed. Southern reedbuck milk seems to have a complex casein composition, similar to that of sheep. Milk composition varies between species. Although some differences may be ascribed to biological condition, such as stage of lactation, or ecological factors, such as availability of certain nutrients, the contribution by evolutionary history is not well documented and the emphasis is usually on the composition of the macro nutrients. Phylogenetic comparisons often lack representatives of multiple species of taxonomic groups and sub-groups. To date phylogenetic comparisons of milk composition have been carried out by using data from different publications. The problem with this approach is that the ecological factors cannot be completely ruled out. A statistical phylogenetic comparison by PCA between 15 species representing 7 different suborders, families or subfamilies of African Artiodactyla was carried out. The phylogenetic properties showed that the milk composition of the Bovinae, represented here by the subfamilies Bovini and Tragelaphini, differs from the other taxonomic groups, in that the Alcelaphinae had a high milk fat content of the medium chain length fatty acids C8–C12 (>17% of total fatty acids) and the Hippotraginae high amounts of oligosaccharides (>0.4%).

      PubDate: 2016-11-30T09:28:34Z
  • Ghrelin in Senegalese sole (Solea senegalensis) post-larvae: Paracrine
           effects on food intake
    • Abstract: Publication date: February 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 204
      Author(s): Carmen Navarro-Guillén, Manuel Yúfera, Sofia Engrola
      Successful food consumption and digestion depend on specifics anatomical and behavioral characteristics and corresponding physiological functions that should be ready to work at the appropriate time. The physiological regulation of appetite and ingestion involves a complex integration of peripheral and central signals by the brain. Ghrelin is a peptide hormone involved in the control of energy homeostasis and increases food intake in mammals, however ghrelin has species-specific actions on food intake in fish. The aim of this study was to investigate whether this peptide has an orexigenic or anorexigenic role in Senegalese sole (Solea senegalensis) in order to improve the knowledge of the physiological basis underlying feeding activity. Feed intake was measured at several sampling points to determine the overall action time of the peptide and its effect in Senegalese sole food intake. Artemia protein digestibility and retention were determined in order to analyze the ghrelin effect in fed and fasted Senegalese sole post-larvae. Results suggested that ghrelin acts as orexigenic hormone in Senegalese sole, with a response time around 25min. Results indicated that Senegalese sole post-larvae are able to maintain absorption and retention capacities independently of feeding rate and nutritional status. Furthermore, the present study gives insight for the first time of the fate of the retained amino acids, being mainly used for protein accretion (86.79% of retained amino acids recovered in protein and FAA fractions).

      PubDate: 2016-11-30T09:28:34Z
  • Forkhead box O1 in grass carp Ctenopharyngodon idella: Molecular
           characterization, gene structure, tissue distribution and mRNA expression
           in insulin-inhibited adipocyte lipolysis
    • Abstract: Publication date: February 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 204
      Author(s): Jian Sun, Pei-zhen Xiao, Zhi-guang Chang, Hong Ji, Zhen-Yu Du, Li-Qiao Chen
      Factor forkhead box O1 (FoxO1) is a transcription factor and plays an important role in insulin-mediated lipid metabolism. In the present study, two distinct FoxO1 cDNAs, designated FoxO1a and FoxO1b, were firstly isolated and characterized from grass carp Ctenopharyngodon idella, encoding peptides of 654 and 631 amino acids, respectively. Phylogenetic and synteny analyses suggested that FoxO1a and FoxO1b were derived from paralogous genes that could be originated from teleost-specific genome duplication (TSGD) event. Analysis of the exon–intron structures clarified that grass carp FoxO1a and FoxO1b comprise 3 coding exons and contain a extra intron compared with human and mouse FoxO1. Both FoxO1a and FoxO1b mRNAs were expressed in a wide range of tissues, but the abundance of each FoxO1 mRNA showed the tissue- dependent expression patterns. Time-course analysis of FoxO1 expressions indicated that the level of FoxO1a mRNA reached almost maximal level at day 2, while that of FoxO1b mRNA reached almost maximal level at day 4 during grass carp primary preadipocyte differentiation. In insulin-inhibited adipocyte lipolysis, only FoxO1a showed a significant decrease in adipocyte, indicating that two FoxO1 isoforms may serve somewhat different roles in the regulation of lipolysis by insulin. These results suggested that grass carp FoxO1a and FoxO1b may play different roles in tissues, and their expression levels were differently modulated by insulin in adipocyte.

      PubDate: 2016-11-30T09:28:34Z
  • Intestinal response to salinity challenge in the Senegalese sole (Solea
    • Abstract: Publication date: February 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 204
      Author(s): I. Ruiz-Jarabo, A. Barany, I. Jerez-Cepa, J.M. Mancera, J. Fuentes
      Fish are continuously forced to actively absorb or expel water and ions through epithelia. Most studies have focused on the gill due to its role in Na+ and Cl− trafficking. However, comparatively few studies have focused on the changing function of the intestine in response to external salinity. Therefore, the present study investigated the main intestinal changes of long-term acclimation of the Senegalese sole (Solea senegalensis) to 5, 15, 38 and 55ppt. Through the measurement of short-circuit current (Isc) in Ussing chambers and biochemical approaches, we described a clear anterior/posterior functional regionalization of the intestine in response to salinity. The use of specific inhibitors in Ussing chamber experiments, revealed that the bumetanide-sensitive Na+/K+/Cl− co-transporters are the main effectors of Cl− uptake in both anterior intestine and rectum. Additionally, the use of the anion exchanger specific inhibitor, DIDS, showed a salinity/region dependency of anion exchanger function. Moreover, we also described ouabain-sensitive Na+/K+-ATPase (NKA) and Bafilomycin A1-sensitive H+-ATPase activities (HA), which displayed changes related to salinity and intestinal region. However, the most striking result of the present study is the description of an omeprazole-sensitive H+/K+-ATPase (HKA) in the rectum of Senegalese sole. Its activity was consistently measurable and increased at lower salinities, reaching rates even higher than those of the NKA. Together our results provide new insights into the changing role of the intestine in response to external salinity in teleost fish. The rectal activity of HKA offers an alternative/cooperative mechanism with the HA in the final processing of intestinal water absorption by apical titration of secreted bicarbonate.

      PubDate: 2016-11-30T09:28:34Z
  • Acute exposure to high environmental ammonia (HEA) triggers the emersion
           response in the green shore crab
    • Abstract: Publication date: February 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 204
      Author(s): Alex M. Zimmer, Chris M Wood
      The physiological effects of high environmental ammonia (HEA) exposure have been well documented in many aquatic species. In particular, it has recently been demonstrated that exposure to ammonia in fish leads to a similar hyperventilatory response as observed during exposure to hypoxia. In littoral crabs, such as the green crab (Carcinus maenas), exposure to severe hypoxia triggers an emersion response whereby crabs escape hypoxia to breathe air. We hypothesized that exposure to HEA in green crabs would lead to a similar behavioural response which is specific to ammonia. Using an experimental arena containing a rock bed onto which crabs could emerse, we established that exposure to HEA (4mmol/l NH4HCO3) for 15min triggers emersion in crabs. In experiments utilizing NaHCO3 controls and NH4HCO3 injections, we further determined that emersion was triggered specifically by external ammonia and was independent of secondary acid-base or respiratory disturbances caused by HEA. We then hypothesized that emersion from HEA provides a physiological benefit, similar to emersion from hypoxia. Exposure to 15min of HEA without emersion (no rock bed present) caused significant increases in arterial haemolymph total ammonia (Tamm), pH, and [HCO3 −]. When emersion was allowed, arterial haemolymph Tamm and [HCO3 −] increased, but no alkalosis developed. Moreover, emersion decreased haemolymph partial pressure of NH3 relative to crabs which could not emerse. Overall, we demonstrate a novel behavioural response to HEA exposure in crabs which we propose may share similar mechanistic pathways with the emersion response triggered by hypoxia.

      PubDate: 2016-11-30T09:28:34Z
  • Antioxidant responses in hibernating Chinese soft-shelled turtle
           Pelodiscus sinensis hatchlings
    • Abstract: Publication date: February 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 204
      Author(s): Wen-yi Zhang, Cui-juan Niu, Bo-jian Chen, Lin Yuan
      The antioxidant defense system protects turtles from oxidative stress during hibernation. The present study examined changes of the antioxidant enzymes both on mRNA level and enzyme activity level during hibernation of Chinese soft-shelled turtle Pelodiscus sinensis hatchlings. The upstream regulator NF-E2 related factor 2 (Nrf2) mRNA was also measured. Samples were taken at pre-hibernation (17.0°C, Mud temperature (MT)), hibernation (5.8°C, MT) and arousal (20.1°C, MT). Nrf2 exhibited a tissue-specific pattern of expression with a decrease in the brain, slight increase in the liver and heart during hibernation, and significant increase during arousal in all the three tissues. Superoxide dismutase (SOD) mRNA, catalase (CAT) mRNA, and glutathione peroxidase 3 (GPx3) mRNA exhibited a similar pattern as Nrf2 in the brain and liver during the entire hibernation period. Hepatic GPx4 mRNA level increased during hibernation and decreased during arousal, whereas it did not change in the heart. Cerebral SOD and CAT activities kept stable during the experimental period, but GPx activity decreased significantly during hibernation and arousal. Hepatic GPx enzyme activity did not change, whereas those of SOD and CAT exhibited a notable decrease during arousal. Malondialdehyde concentration did not increase during the hibernation process, indicating an effective protection of the antioxidant defense system.

      PubDate: 2016-11-23T05:31:06Z
  • l-Leucine acts as a potential agent in reducing body temperature at
           hatching and affords thermotolerance in broiler chicks
    • Abstract: Publication date: February 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 204
      Author(s): Guofeng Han, Hui Yang, Mohammad A. Bahry, Phuong V. Tran, Phong H. Do, Hiromi Ikeda, Mitsuhiro Furuse, Vishwajit S. Chowdhury
      Thermal manipulation (TM) of incubation temperature causes metabolic alterations and contributes to improving thermotolerance in chicks post hatching. However, there has been no report on amino acid metabolism during TM and the part it plays in thermotolerance. In this study, we therefore first analyzed free amino acid concentrations in the embryonic brain and liver during TM (38.6°C, 6h/d during embryonic day (ED) 10 to ED 18). It was found that leucine (Leu), phenylalanine and lysine were significantly decreased in the embryonic brain and liver. We then chose l-Leu and other branched-chain amino acids (l-isoleucine (L-Ile) and l-valine (l-Val)) for in ovo injection on ED 7 to reveal their roles in thermoregulation, growth, food intake and thermotolerance in chicks. It was found that in ovo injection of l-Leu, but not of l-Ileu or l-Val, caused a significant decline in body temperature at hatching and increased food intake and body weight gain in broiler chicks. Interestingly, in ovo injection of l-Leu resulted in the acquisition of thermotolerance under high ambient temperature (35±1°C for 180min) in comparison with the control thermoneutral temperature (28±1°C for 180min). These results indicate that the free amino acid concentrations during embryogenesis were altered by TM. l-Leu administration in eggs caused a reduction in body temperature at hatching, and afforded thermotolerance in heat-exposed young chicks, further suggesting that l-Leu may be one of the key metabolic factors involved in controlling body temperature in embryos, as well as in producing thermotolerance after hatching.

      PubDate: 2016-11-23T05:31:06Z
  • Synchronization to light and mealtime of daily rhythms of locomotor
           activity, plasma glucose and digestive enzymes in the Nile tilapia
           (Oreochromis niloticus)
    • Abstract: Publication date: February 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 204
      Author(s): Bartira Guerra-Santos, José Fernando López-Olmeda, Bruno Olivetti de Mattos, Alice Borba Baião, Denise Soledade Peixoto Pereira, Francisco Javier Sánchez-Vázquez, Robson Bahia Cerqueira, Ricardo Castelo Branco Albinati, Rodrigo Fortes-Silva
      The light–dark cycle and feeding can be the most important factors acting as synchronizers of biological rhythms. In this research we aimed to evaluate synchronization to feeding schedule of daily rhythms of locomotor activity and digestive enzymes of tilapia. For that purpose, 120 tilapias (65.0±0.6g) were distributed in 12 tanks (10 fish per tank) and divided into two groups. One group was fed once a day at 11:00h (zeitgeber time, ZT6) (ML group) and the other group was fed at 23:00h (ZT18) (MD group). The fish were anesthetized to collect samples of blood, stomach and midgut at 4-hour intervals over a period of 24h. Fish fed at ML showed a diurnal locomotor activity (74% of the total daily activity occurring during the light phase) and synchronization to the feeding schedule, as this group showed anticipation to the feeding time. Fish fed at MD showed a disruption in the pattern of locomotor activity and became less diurnal (59%). Alkaline protease activity in the midgut showed daily rhythm with the achrophase at the beginning of the dark phase in both ML and MD groups. Acid protease and amylase did not show significant daily rhythms. Plasma glucose showed a daily rhythm with the achrophase shifted by 12h in the ML and MD groups. These results revealed that the feeding time and light cycle synchronize differently the daily rhythms of behavior, digestive physiology and plasma metabolites in the Nile tilapia, which indicate the plasticity of the circadian system and its synchronizers.

      PubDate: 2016-11-23T05:31:06Z
  • Dietary alpha-ketoglutarate promotes higher protein and lower
           triacylglyceride levels and induces oxidative stress in larvae and young
           adults but not in middle-aged Drosophila melanogaster
    • Abstract: Publication date: February 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 204
      Author(s): Maria M. Bayliak, Maria P. Lylyk, Halyna V. Shmihel, Oksana M. Sorochynska, Olesia I. Semchyshyn, Janet M. Storey, Kenneth B. Storey, Volodymyr I. Lushchak
      Alpha-ketoglutarate (AKG) is involved in multiple metabolic and regulatory pathways. In this work, the effects of AKG-supplemented diets on selected physiological responses and metabolic processes, including metabolism of reactive oxygen species, was assessed in larvae and adult (both 2 and 24days old) Drosophila melanogaster. Dietary supplementation with AKG resulted in dose-dependent effects on larval development, body composition and antioxidant status of third instar larvae. Larvae and young (2days post-eclosion) adult females fed on AKG shared similar metabolic changes such as higher total protein levels, lower triacylglyceride levels and higher values for oxidative stress indices, namely lipid peroxides and low molecular mass thiols. The latter indicated the development of oxidative stress which, in turn, may induce adaptive responses that can explain the higher resistance of AKG-fed young females to heat shock and hydrogen peroxide exposure. In contrast to young flies, middle-aged females (24days) on AKG-containing diet possessed higher total protein, glucose and triacylglyceride levels, whereas oxidative stress parameters were virtually the same as compared with control females of the same age. In parallel, females fed an AKG-supplemented diet showed lower fecundity, higher heat shock resistance but no change in oxidative stress resistance at middle age which in combination with levels of protein, glucose, and triacylglycerides can be considered as potentially beneficial AKG effects for aging organisms. To our best knowledge, this is the first study on age-matched AKG influence on animals' organism which shows that Drosophila may be used as a model for previous quick study in cost-efficient manner age-related AKG effects in mammals and humans.

      PubDate: 2016-11-23T05:31:06Z
  • Biological and environmental influence on tissue fatty acid compositions
           in wild tropical tunas
    • Abstract: Publication date: February 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 204
      Author(s): Fany Sardenne, Edouard Kraffe, Aurélien Amiel, Edwin Fouché, Laurent Debrauwer, Frédéric Ménard, Nathalie Bodin
      This study examined the fatty acid composition of three sympatric tropical tuna species (bigeye Thunnus obesus, yellowfin T. albacares and skipjack tuna Kastuwonus pelamis) sampled in the Western Indian Ocean in 2013. The fatty acid compositions of neutral and polar lipids, respectively involved in energy storage and cell membrane structure, were explored and compared in four tissues (red and white muscles, liver and gonads), according to biological (size, sex and maturity) and environmental (season and area) factors. The liver and the red muscle were the fattest tissues (i.e., higher levels of storage lipids) in all species and polar lipids were the lowest in the white muscle. Species and tissue types explained most differences in fatty acid compositions, while environmental factors had limited effects, except in the hepatic cell membrane where fatty acid composition varied with monsoons. Docosahexaenoic acid (22:6n-3) was the major fatty acid in both polar and neutral lipid fractions, especially in muscles. Eicosapentaenoic acid (20:5n-3) and oleic acid (18:1n-9) were in higher proportion in neutral than in polar lipids. Arachidonic acid (20:4n-6) and 22:6n-3, together with docosapentaenoic acid (22:5n-6) and stearic acid (18:0), showed preferential accumulation in polar lipids. 20:4n-6 was particularly involved in cell membranes of ovary and white muscle. Overall, an important inter-individual variability in fatty acid compositions of structural lipids was found within tissue types despite considering biological factors that are most likely to influence this type of lipids. It suggests that fatty acid profiles are influenced by individual-specific behaviors.

      PubDate: 2016-11-23T05:31:06Z
  • Cortisol regulates nitric oxide synthase in freshwater and seawater
           acclimated rainbow trout, Oncorhynchus mykiss
    • Abstract: Publication date: February 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 204
      Author(s): Lucie Gerber, Steffen S. Madsen, Frank B. Jensen
      Cortisol and nitric oxide (NO) are regulators of ion transport and metabolic functions in fish. In the gill, they show opposite effects on Na+/K+-ATPase (NKA) activity: cortisol stimulates NKA activity while NO inhibits NKA activity. We hypothesized that cortisol may impact NO production in osmoregulatory tissues by regulating NO synthase (NOS) expression. We evaluated the influence of cortisol treatment on mRNA expression of Nos1 and Nos2 in gill, kidney and middle intestine of both freshwater (FW) and seawater (SW) acclimated rainbow trout and found both tissue- and salinity-dependent effects. Nos2 expression was down-regulated in the gill by cortisol injection in both FW and SW trout. This was substantiated by incubating gill tissue with cortisol ex vivo. Similarly, cortisol injection significantly down-regulated Nos2 expression in kidney of SW fish but not in FW fish. In the middle intestine, Nos2 expression was up-regulated by cortisol injection in FW but unchanged in SW fish. Nos1 expression was up-regulated by cortisol injection in FW kidney and down-regulated in SW kidney, whereas it was unaffected in gill and middle intestine of FW and SW fish. Our data provide the first evidence that cortisol may influence NO production in fish by regulating Nos expression. Indeed, the down-regulation of Nos2 expression by cortisol in the gill may prevent the inhibitory effect of NO on NKA activity thereby furthering the stimulatory effect of cortisol on ion-transport.

      PubDate: 2016-11-17T03:37:58Z
  • Physiological and molecular responses of juvenile shortnose sturgeon
           (Acipenser brevirostrum) to thermal stress
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Yueyang Zhang, Jennifer R. Loughery, Christopher J. Martyniuk, James D. Kieffer
      The shortnose sturgeon (Acipenser brevirostrum LeSueur, 1818) is a vulnerable species that is found along the eastern coast of North America. Little is known about temperature tolerance in this species and with a rapidly changing global climate, it becomes increasingly important to define the thermal tolerance of this species to better predict population distribution. Using a modified critical thermal maximum test (CTMax), the objectives of this study were to determine the impact of heating rate (0.1, 0.2 and 0.25°Cmin−1) on the thermal tolerance, associated hematological responses, and oxygen consumption in juvenile sturgeon. In addition, transcripts associated with physiological stress and heat shock (i.e., heat shock proteins) were also measured. Heating rate did not alter the CTMax values of shortnose sturgeon. Neither heating rate nor thermal stress affected plasma sodium and chloride levels, nor the expression of transcripts that included catalase, glucocorticoid receptor, heat shock protein70 (hsp70), heat shock protein 90α (hsp90α) and cytochrome P450 1a (cyp1a). However, regardless of heating rate, thermal stress increased both plasma potassium and lactate concentrations. Glucose levels were increased at heating rates of 0.2 and 0.25°Cmin−1, but not at 0.1°Cmin−1. Overall, oxygen consumption rates increased with thermal stress, but the response patterns were not affected by heating rate. These data support the hypothesis that shortnose sturgeon can tolerate acute heat stress, as many physiological and molecular parameters measured here were non-responsive to the thermal stress.

      PubDate: 2016-11-10T01:55:38Z
  • Desensitization and recovery of crayfish photoreceptors. Dependency on
           circadian time, and pigment-dispersing hormone
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Carolina Barriga-Montoya, Araceli de la O-Martínez, Beatriz Fuentes-Pardo, Froylán Gómez-Lagunas
      In this work, we studied the characteristics of recovery from desensitization of the light-elicited current of crayfish. Applying a two-flash protocol, we found that the first flash triggers a current that activates with a noticeable latency, reaches a peak value, and thereafter decays along a single exponential time course. In comparison with the first-elicited current, the current elicited by the second flash not only presents an expected smaller peak current, depending on the time between flashes, but it also displays a different latency and decay time constant. Recovery of the first flash values of these current parameters depends on the circadian time at which the experiments are conducted, and on the presence of pigment-dispersing hormone. Our data also suggest the existence of distinctive desensitized states, whose induction depends on circadian time and the presence of pigment-dispersing hormone.

      PubDate: 2016-11-03T00:26:12Z
  • Cold and desiccation stress induced changes in the accumulation and
           utilization of proline and trehalose in seasonal populations of Drosophila
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Aditya Moktan Tamang, Bhawna Kalra, Ravi Parkash
      Changes in the levels of energy metabolites can limit survival ability of Drosophila species under stressful conditions but this aspect has received less attention in wild populations collected in different seasons. We tested cold or desiccation triggered changes in the accumulation or utilization of two energy metabolites (trehalose and proline) in Drosophila immigrans flies reared under season specific environmental conditions. Such D. immigrans populations were subjected to different durations of cold (0°C) or desiccation stress (5% RH) or dual stress. We found stress induced effects of cold vs desiccation on the levels of trehalose as well as for proline. Different durations of cold stress led to accumulation of trehalose while desiccation stress durations revealed utilization of trehalose. In contrast, there was accumulation of proline under desiccation and utilization of proline with cold stress. Since accumulation levels were higher than utilization of each energy metabolite, the effects of dual stress showed additive effect. However, there was no utilization of total body lipids under cold or desiccation stress. We observed significant season specific differences in the amount of energy metabolites but the rate of metabolism did not vary across seasons. Stress triggered changes in trehalose and proline suggest possible link between desiccation and cold tolerance. Finally, stress specific (cold or desiccation) compensatory changes in the levels of trehalose and proline suggest possible energetic homeostasis in D. immigrans living under harsh climatic conditions of montane localities.

      PubDate: 2016-11-03T00:26:12Z
  • Gill remodelling and growth rate of striped catfish Pangasianodon
           hypophthalmus under impacts of hypoxia and temperature
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Le My Phuong, Do Thi Thanh Huong, Jens Randel Nyengaard, Mark Bayley
      Gill morphometric and gill plasticity of the air-breathing striped catfish (Pangasianodon hypophthalmus) exposed to different temperatures (present day 27°C and future 33°C) and different air saturation levels (92% and 35%) during 6weeks were investigated using vertical sections to estimate the respiratory lamellae surface areas, harmonic mean barrier thicknesses, and gill component volumes. Gill respiratory surface area (SA) and harmonic mean water - blood barrier thicknesses (HM) of the fish were strongly affected by both environmental temperature and oxygen level. Thus initial values for 27°C normoxic fish (12.4±0.8g) were 211.8±21.6mm2 g−1 and 1.67±0.12μm for SA and HM respectively. After 5weeks in same conditions or in the combinations of 33°C and/or PO2 of 55mmHg, this initial surface area scaled allometrically with size for the 33°C hypoxic group, whereas branchial SA was almost eliminated in the 27°C normoxic group, with other groups intermediate. In addition, elevated temperature had an astounding effect on growth with the 33°C group growing nearly 8-fold faster than the 27°C fish.

      PubDate: 2016-10-27T21:48:16Z
  • Do physical habitat complexity and predator cues influence the baseline
           and stress-induced glucocorticoid levels of a mangrove-associated
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Jennifer M.T. Magel, Naomi Pleizier, Alexander D.M. Wilson, Aaron D. Shultz, Marilyn N. Vera Chang, Thomas W. Moon, Steven J. Cooke
      As human populations continue to expand, increases in coastal development have led to the alteration of much of the world's mangrove habitat, creating problems for the multitude of species that inhabit these unique ecosystems. Habitat alteration often leads to changes in habitat complexity and predation risk, which may serve as additional stressors for those species that rely on mangroves for protection from predators. However, few studies have been conducted to date to assess the effects of these specific stressors on glucocorticoid (GC) stress hormone levels in wild fish populations. Using the checkered puffer as a model, our study sought to examine the effects of physical habitat complexity and predator environment on baseline and acute stress-induced GC levels. This was accomplished by examining changes in glucose and cortisol concentrations of fish placed in artificial environments for short periods (several hours) where substrate type and the presence of mangrove roots and predator cues were manipulated. Our results suggest that baseline and stress-induced GC levels are not significantly influenced by changes in physical habitat complexity or the predator environment using the experimental protocol that we applied. Although more research is required, the current study suggests that checkered puffers may be capable of withstanding changes in habitat complexity and increases in predation risk without experiencing adverse GC-mediated physiological effects, possibly as a result of the puffers' unique morphological and chemical defenses that help them to avoid predation in the wild.

      PubDate: 2016-10-27T21:48:16Z
  • Laboratory studies on the thermal tolerance and response of enzymes of
           intermediate metabolism in different land snail species
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Alexandra Staikou, Evagelia Kesidou, Marina-Elena Garefalaki, Basile Michaelidis
      Land snails species occur in a range of habitats from humid to semi-arid and arid ones and seasonal variations in their physiology and biochemical composition have been linked to annual cycles of photoperiod, temperature, humidity and water availability. In an effort to understand the thermal tolerance and the impact of temperature elevation on tissue metabolism of land snails we determined the mortality, heamolymph PO 2 and the activities of enzymes of intermediary metabolism in three land snail species (Helix lucorum, Helix pomatia and Cornu aspersum) differing in their geographical distribution and inhabiting areas with different climatic characteristics. No mortality was observed in both population of Cornu aspersum, while Helix pomatia exhibited higher mortality than Helix lucorum. PO 2 dropped within the first 10days of exposure to elevated temperature in all species, although in Cornu aspersum this decrease was significantly lower. No significant reduction in the enzymatic activities of all glycolytic enzymes studied, as well as of citrate synthase (CS) and 3-hydroxyacyl-CoA dehydrogenase (HOAD) was observed in the more thermal tolerant species C. aspersum from both populations studied. Significant reductions of enzymatic activity of the glycolytic enzymes phosphofructokinase (PFK), pyruvate kinase (PK) and d-Lactate dehydrogenase (d-LDH) was observed in Helix lucorum and Helix pomatia. The observed inter-specific differences seem to be in accordance with the life cycle characteristics of each species and may be attributed to climatic differences among habitats within their distribution range.

      PubDate: 2016-10-27T21:48:16Z
  • The role of the autonomic nervous system in control of cardiac and
           air-breathing responses to sustained aerobic exercise in the African
           sharptooth catfish Clarias gariepinus
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Felipe R. Blasco, David J. McKenzie, Edwin W. Taylor, F. Tadeu Rantin
      Clarias gariepinus is a facultative air-breathing catfish that exhibits changes in heart rate (ƒH) associated with air-breaths (AB). A transient bradycardia prior to the AB is followed by sustained tachycardia during breath-hold. This study evaluated air-breathing and cardiac responses to sustained aerobic exercise in juveniles (total length~20cm), and how exercise influenced variations in f H associated with AB. In particular, it investigated the role of adrenergic and cholinergic control in cardiac responses, and effects of pharmacological abolition of this control on air-breathing responses. Sustained exercise at 15, 30 and 45cms−1 in a swim tunnel caused significant increases in f AB and f H, from approximately 5breathsh−1 and 60heartbeatsmin−1 at the lowest speed, to over 60breathsh−1 and 100beatsmin−1 at the highest, respectively. There was a progressive decline in the degree of variation in f H, around each AB, as f AB increased with exercise intensity. Total autonomic blockade abolished all variation in f H during exercise, and around each AB, but f AB responses were the same as in untreated animals. Cardiac responses were exclusively due to modulation of inhibitory cholinergic tone, which varied from >100% at the lowest speed to <10% at the highest. Cholinergic blockade had no effect on f AB compared to untreated fish. Excitatory β-adrenergic tone was approximately 20% and did not vary with swimming speed, but its blockade increased f AB at all speeds, compared to untreated animals. This reveals complex effects of autonomic control on air-breathing during exercise in C. gariepinus, which deserve further investigation.

      PubDate: 2016-10-27T21:48:16Z
  • Osmotic versus adrenergic control of ion transport by ionocytes of
           Fundulus heteroclitus in the cold
    • Abstract: Publication date: January 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 203
      Author(s): Janet C. Tait, Evan W. Mercer, Lucie Gerber, George N. Robertson, William S. Marshall
      In eurythermic vertebrates, acclimation to the cold may produce changes in physiological control systems. We hypothesize that relatively direct osmosensitive control will operate better than adrenergic receptor mediated control of ion transport in cold vs. warm conditions. Fish were acclimated to full strength seawater (SW) at 21°C and 5°C for four weeks, gill samples and blood were taken and opercular epithelia mounted in Ussing style chambers. Short-circuit current (I sc ) at 21°C and 5°C (measured at acclimation temperature), was significantly inhibited by the α2-adrenergic agonist clonidine but the ED50 dose was significantly higher in cold conditions (93.8±16.4nM) than in warm epithelia (47.8±8.1nM) and the maximum inhibition was significantly lower in cold (−66.1±2.2%) vs. warm conditions (−85.6±1.3%), indicating lower sensitivity in the cold. β-Adrenergic responses were unchanged. Hypotonic inhibition of I sc , was higher in warm acclimated (−95%), compared to cold acclimated fish (−75%), while hypertonic stimulations were the same, indicating equal responsiveness to hyperosmotic stimuli. Plasma osmolality was significantly elevated in cold acclimated fish and, by TEM, gill ionocytes from cold acclimated fish had significantly shorter mitochondria. These data are consistent with a shift in these eurythermic animals from complex adrenergic control to relatively simple biomechanical osmotic control of ion secretion in the cold.

      PubDate: 2016-10-27T21:48:16Z
  • 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
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