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  Subjects -> BIOLOGY (Total: 2995 journals)
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BIOCHEMISTRY (235 journals)                  1 2 | Last

Showing 1 - 200 of 235 Journals sorted alphabetically
AAPS PharmSciTech     Hybrid Journal   (Followers: 6)
Acetic Acid Bacteria     Open Access   (Followers: 2)
ACS Central Science     Open Access   (Followers: 6)
ACS Chemical Biology     Full-text available via subscription   (Followers: 242)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 17)
Acta Crystallographica Section D : Biological Crystallography     Hybrid Journal   (Followers: 8)
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: 8)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19)
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: 8)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 67)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 14)
American Journal of Polymer Science     Open Access   (Followers: 25)
Amino Acids     Hybrid Journal   (Followers: 8)
Analytical Biochemistry     Hybrid Journal   (Followers: 163)
Angiogenesis     Hybrid Journal   (Followers: 3)
Annals of Clinical Biochemistry     Hybrid Journal   (Followers: 7)
Annual Review of Biochemistry     Full-text available via subscription   (Followers: 56)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 13)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 44)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 17)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Archives of Biochemistry and Biophysics     Hybrid Journal   (Followers: 20)
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: 21)
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: 25)
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemical Society Transactions     Full-text available via subscription   (Followers: 4)
Biochemical Systematics and Ecology     Hybrid Journal   (Followers: 3)
Biochemistry     Full-text available via subscription   (Followers: 288)
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     Hybrid Journal   (Followers: 14)
Biochemistry and Molecular Biology Education     Hybrid Journal   (Followers: 6)
Biochemistry and Molecular Biology of Fishes     Full-text available via subscription   (Followers: 1)
Biochemistry Research International     Open Access   (Followers: 6)
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids     Hybrid Journal   (Followers: 7)
Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease     Hybrid Journal   (Followers: 14)
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research     Hybrid Journal   (Followers: 9)
Biochimie     Hybrid Journal   (Followers: 7)
Biochimie Open     Open Access  
Bioconjugate Chemistry     Full-text available via subscription   (Followers: 29)
BioDrugs     Full-text available via subscription   (Followers: 7)
Bioelectrochemistry     Hybrid Journal   (Followers: 2)
Biofuels     Hybrid Journal   (Followers: 10)
Biogeochemistry     Hybrid Journal   (Followers: 14)
BioInorganic Reaction Mechanisms     Hybrid Journal   (Followers: 1)
Biokemistri     Open Access  
Biological Chemistry     Partially Free   (Followers: 22)
Biomaterials Research     Open Access   (Followers: 4)
Biomedicines     Open Access   (Followers: 1)
BioMolecular Concepts     Hybrid Journal   (Followers: 2)
Bioscience, Biotechnology, and Biochemistry     Hybrid Journal   (Followers: 24)
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: 8)
Cell Biochemistry and Biophysics     Hybrid Journal   (Followers: 6)
Cell Biochemistry and Function     Hybrid Journal   (Followers: 6)
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: 20)
Chemical Engineering Journal     Hybrid Journal   (Followers: 41)
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: 6)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry and Ecology     Hybrid Journal  
ChemTexts     Hybrid Journal  
Clinica Chimica Acta     Hybrid Journal   (Followers: 33)
Clinical Biochemist Reviews     Full-text available via subscription   (Followers: 1)
Clinical Biochemistry     Hybrid Journal   (Followers: 18)
Clinical Chemistry     Full-text available via subscription   (Followers: 66)
Clinical Chemistry and Laboratory Medicine     Hybrid Journal   (Followers: 59)
Clinical Lipidology     Full-text available via subscription   (Followers: 1)
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: 8)
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: 12)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Current Chemical Biology     Hybrid Journal   (Followers: 2)
Current Medicinal Chemistry     Hybrid Journal   (Followers: 16)
Current Opinion in Chemical Biology     Hybrid Journal   (Followers: 27)
Current Opinion in Lipidology     Hybrid Journal   (Followers: 6)
DNA Barcodes     Open Access  
Doklady Biochemistry and Biophysics     Hybrid Journal   (Followers: 1)
Doklady Chemistry     Hybrid Journal  
Egyptian Journal of Biochemistry and Molecular Biology     Full-text available via subscription  
FABICIB     Open Access  
FEBS Letters     Hybrid Journal   (Followers: 56)
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: 4)
Frontiers in Molecular Biosciences     Open Access   (Followers: 2)
Frontiers in Natural Product Chemistry     Hybrid Journal  
Global Biogeochemical Cycles     Full-text available via subscription   (Followers: 15)
Green Chemistry     Full-text available via subscription   (Followers: 10)
Histochemistry and Cell Biology     Hybrid Journal   (Followers: 5)
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: 8)
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   (Followers: 1)
International Journal of Plant Research     Open Access   (Followers: 3)
International Journal of Secondary Metabolite     Open Access   (Followers: 1)
Invertebrate Immunity     Open Access   (Followers: 1)
JBIC Journal of Biological Inorganic Chemistry     Hybrid Journal   (Followers: 4)
Journal of Microbial & Biochemical Technology     Open Access   (Followers: 2)
Journal of Applied Biology & Biotechnology     Open Access   (Followers: 2)
Journal of Bioactive and Compatible Polymers     Hybrid Journal   (Followers: 2)
Journal of Biochemistry     Hybrid Journal   (Followers: 43)
Journal of Biochemistry and Molecular Biology Research     Open Access  
Journal of Biological Chemistry     Full-text available via subscription   (Followers: 192)
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: 2)
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  
Journal of Enzyme Inhibition and Medicinal Chemistry     Hybrid Journal   (Followers: 3)
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: 4)
Journal of Inborn Errors of Metabolism and Screening     Open Access  
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 6)
Journal of Medical and Biomedical Sciences     Open Access  
Journal of Medical Biochemistry     Open Access   (Followers: 4)
Journal of Medicine and Biomedical Research     Open Access   (Followers: 1)
Journal of Molecular Biochemistry     Open Access   (Followers: 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: 22)
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: 6)
Journal of Steroid Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 2)
Journal of Virology & Antiviral Research     Hybrid Journal   (Followers: 5)
Journal of Wood Chemistry and Technology     Hybrid Journal   (Followers: 8)
La Rivista Italiana della Medicina di Laboratorio - Italian Journal of Laboratory Medicine     Hybrid Journal  
Lab on a Chip     Full-text available via subscription   (Followers: 35)
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: 6)
Molecular Aspects of Medicine     Hybrid Journal   (Followers: 3)
Molecular Informatics     Hybrid Journal   (Followers: 6)
Molecular inhibitors in targeted therapy     Open Access  
Moscow University Chemistry Bulletin     Hybrid Journal   (Followers: 1)
Mycologia     Hybrid Journal  
Mycology : An International Journal on Fungal Biology     Hybrid Journal   (Followers: 5)
Natural Products and Bioprospecting     Open Access   (Followers: 2)
Nature Chemical Biology     Full-text available via subscription   (Followers: 72)
Nature Communications     Open Access   (Followers: 178)
Neurosignals     Open Access  
NOVA     Open Access  
Novelty in Biomedicine     Open Access  
OA Biochemistry     Open Access   (Followers: 1)
OA Inflammation     Open Access  
Ocean Acidification     Open Access   (Followers: 3)
Organic & Biomolecular Chemistry     Full-text available via subscription   (Followers: 89)
Peptidomics     Open Access  

        1 2 | Last

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  [3043 journals]
  • Characterization of two odorant binding proteins in Spodoptera exigua
           reveals functional conservation and difference
    • Abstract: Publication date: Available online 12 August 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Nai-Yong Liu, Jia-Yao Zhu, Ting Zhang, Shuang-Lin Dong
      As the first biochemical step of olfactory reception and recognition, odorant binding proteins (OBPs) have been demonstrated to be essential. Considering functional diversities of OBPs within a single species, we here extended the characterization of two other OBPs from Spodoptera exigua, belonging to insect Classic OBPs. With a combination of transcriptome and Rapid Amplification of cDNA End (RACE) approaches, two OBP genes in S. exigua were first identified, namely SexiOBP1 and OBP7. Expression pattern analysis revealed that both of them exhibited a distinct expression, where OBP1 was broadly and highly expressed in several tissues including antennae of adults whereas OBP7 was abundant only in the antennae of both sexes, strongly indicative of olfactory roles. Further, binding assays showed that the two SexiOBPs shared a common odorant-response spectrum with considerable affinities to host odorants of acetophenone, farnesol and β-ionone (K i <20μM). Specially, OBP1 could strongly bind an insect attractant β-caryophyllene (K i = 2.76μM) released by maize. Intriguingly, the major sex pheromone of S. exigua, Z9,E12-14:Ac, was the best ligand for OBP7 with K i value of 7.58μM. Ligand structural analysis revealed that the two SexiOBPs were capable of accommodating different types of ligands in shape and size, possibly implying the plasticity of binding pockets. Ultimately, comparison of binding properties among 10 SexiOBPs including the two OBPs in this study implied a cross-talk in functions, i.e. different OBPs are also suitable to accept some common odorants except for unique ligands. Taken together, this study has provided evidence for their involvements in seeking and orientation of host plants, and meanwhile indicates functional conservation and difference between OBP1 and OBP7 from S. xigua.

      PubDate: 2017-08-15T11:55:17Z
       
  • Altitudinal variation in metabolic parameters of a small Afrotropical bird
    • Abstract: Publication date: October 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 212
      Author(s): Lindy J. Thompson, Colleen T. Downs
      Of the numerous factors affecting avian metabolic rate, altitude is one of the least studied. We used mass-flow respirometry to measure resting metabolic rate (RMR), evaporative water loss (EWL) and respiratory exchange ratio (RER) in two populations of a small (10–12g) Afrotropical bird, the Cape White-eye (Zosterops virens), in summer and in winter. In total, 51 freshly wild-caught adult Cape White-eyes were measured overnight. Altitude was included as a source of variation in the best approximating models for body mass, whole-animal RMR, RER, whole-animal standard EWL and whole-animal basal EWL. RER was significantly lower in winter, suggesting a greater proportion of lipid oxidation at lower ambient temperatures (Ta). Cape White-eyes were 0.8g heavier at the higher altitude site and 0.5g heavier in winter, suggesting they may have increased their metabolic machinery to cope with cooler temperatures. EWL was generally significantly lower in winter than in summer, suggesting that birds may increase EWL with increasing Ta, as the need for evaporative cooling increases. Our results support the argument that the subtle and complex effects of altitude (and ambient temperature) should be taken into account in studies on avian metabolic rate. What is already known Of the numerous studies known to affect avian metabolic rate, altitude is one of the least studied. Although trends are not always clear, generally, at higher altitudes, avian metabolic rate increases. What the study adds There were statistically significant seasonal and altitudinal differences in various physiological parameters of Cape White-eyes. These results highlight the importance of accounting for altitude in studies of avian metabolic rate.

      PubDate: 2017-08-05T11:02:51Z
       
  • Peripheral neuropeptide Y differentially influences adipogenesis and
           lipolysis in chicks from lines selected for low or high body weight
    • Abstract: Publication date: Available online 5 August 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Lingbin Liu, Guoqing Wang, Yang Xiao, Steven L. Shipp, Paul B. Siegel, Mark A. Cline, Elizabeth R. Gilbert
      Neuropeptide Y (NPY) stimulates appetite and promotes lipid deposition. We demonstrated a differential sensitivity in the food intake response to central NPY in chicks from lines selected for low (LWS) or high (HWS) body weight, but have not reported whether such differences exist in the periphery. At 5days, LWS and HWS chicks were intraperitoneally injected with 0 (vehicle), 60, or 120μg/kg BW NPY and subcutaneous adipose tissue and plasma were collected at 1, 3, 6, 12, and 24h (n =12). NPY injection increased glycerol-3-phosphate dehydrogenase (G3PDH) activity at 1 and 3h and reduced plasma NEFAs at 1 and 12h. G3PDH activity was greater in HWS than LWS while NEFAs were greater in LWS. At 1h, peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer binding protein (C/EBP)α, and microsomal triglyceride transfer protein (MTTP) mRNAs were reduced in NPY-injected chicks whereas NPY receptor 1 (NPYR1) was increased. Expression of stearoyl-CoA desaturase (SCD1) was increased by NPY at 1h in HWS but not LWS. PPARγ (3 and 6h), C/EBPβ (3h), C/EBPα (6h) and NPYR1 and 2 (24h) mRNAs were greater in NPY- than vehicle-injected chicks. At several times, adipose triglyceride lipase, MTTP, perilipin 1, NPYR1, and NPYR2 mRNAs were greater in LWS than HWS, while expression of SCD1, glycerol-3-phosphate acyltransferase 3 and lipoprotein lipase was greater in HWS than LWS. Thus, NPY promotes fat deposition and inhibits lipolysis in chicks, with line differences indicative of greater rates of lipolysis in LWS and adipogenesis in HWS.

      PubDate: 2017-08-05T11:02:51Z
       
  • Aerobic scope in chicken embryos
    • Abstract: Publication date: Available online 31 July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Satoko T. Ide, Ryoji Ide, Jacopo P. Mortola
      We investigated the aerobic scope of chicken embryos, that is, the margin of increase of oxygen consumption ( V ̇ O 2 ) above its normal value. V ̇ O 2 was measured by an open-flow methodology at embryonic ages E3, E7, E11, E15, E19 and at E20 at the internal (IP) and external pipping (EP) phases, at the normal incubation temperature (Ta=38°C), in hypothermia (Ta=30°C) and in hyperthermia (Ta=41 and 44°C). In the cold, Q10 averaged ~2 at all ages, except in IP and EP when lower values (~1.5) indicated some degree of thermogenesis. In hyperthermia (38–44°C) Q10 was between 1 and 1.4. Hyperthermia had no significant effects on V ̇ O 2 whether the results combined all ages or considered individual age groups, except in IP (in which V ̇ O 2 increased 8% with 44°C) and EP embryos (+13%). After opening the air cell, which exposed the embryo to a higher O2 pressure, hyperthermic V ̇ O 2 was significantly higher than in normothermia in E19 (+13%), IP (+22%) and EP embryos (+22%). We conclude that in chicken embryos throughout most of incubation neither heat nor oxygen availability limits the normal (normoxic-normothermic) values of V ̇ O 2 . Only close to hatching O2-diffusion represents a limiting factor to the embryo's V ̇ O 2 . Hence, embryos differ from postnatal animals for a nearly absent aerobic scope, presumably because their major sources of energy expenditure (growth and tissue maintenance) are constantly maximized.

      PubDate: 2017-08-05T11:02:51Z
       
  • Rhythmicity and plasticity of digestive physiology in a euryhaline teleost
           fish, permit (Trachinotus falcatus)
    • Abstract: Publication date: Available online 29 July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Carlo C. Lazado, Per Bovbjerg Pedersen, Quang Huy Nguyen, Ivar Lund
      Digestive physiology is considered to be under circadian control, but there is little evidence in teleost fish. The present study explored the rhythmicity and plasticity to feeding schedules of enzymatic digestion in a candidate aquaculture fish, the permit (Trachinotus falcatus). The first experiment identified the rhythms of digestive factors throughout the light-dark (LD) cycle. Gastric luminal pH and pepsin activity showed significant daily variation albeit not rhythmic. These dynamic changes were likewise observed in several digestive enzymes, in which the activities of intestinal protease, chymotrypsin and lipase exhibited significant daily rhythms. In the second experiment, the existence of feed anticipatory activity in the digestive factors was investigated by subjecting the fish to either periodic or random feeding. Anticipatory gastric acidification prior to feeding was identified in periodically fed fish. However, pepsin activity did not exhibit such anticipation but a substantial postprandial increase was observed. Intestinal protease, leucine aminopeptidase and lipase anticipated periodic mealtime with elevated enzymatic activities. Plasma melatonin and cortisol demonstrated robust daily rhythms but feeding time manipulations revealed no significant impact. Plasma ghrelin level remained constant during the LD cycle and appeared to be unaffected by differing feeding regimes as well. Taken together, the digestive factors of permit were highly dynamic during the LD cycle. Periodic feeding entrained digestive physiology and mediated anticipatory gastric acidification and intestinal enzymatic activities. This knowledge will be essential in developing feeding protocols and husbandry-related welfare strategies that will further advance this candidate finfish as an aquaculture species.

      PubDate: 2017-08-05T11:02:51Z
       
  • Transcriptional, translational and systemic alterations during the time
           course of osmoregulatory acclimation in two palaemonid shrimps from
           distinct osmotic niches
    • Abstract: Publication date: Available online 29 July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Rogério Oliveira Faleiros, Rosa P.M. Furriel, John Campbell McNamara
      Palaemonid shrimps exhibit numerous adaptive strategies, both in their life cycles and in biochemical, physiological, morphological and behavioral characteristics that reflect the wide variety of habitats in which they occur, including species that are of particular interest when analyzing adaptive osmoregulatory strategies. The present investigation evaluates the short- (hours) and long-term (days) time courses of responses of two palaemonid shrimps from separate yet overlapping osmotic niches, Palaemon northropi (marine) and Macrobrachium acanthurus (diadromous, fresh water), to differential salinity challenges at distinct levels of structural organization: (i) transcriptional, analyzing quantitative expression of gill mRNAs that encode for subunits of the Na+/K+-ATPase and V(H+)-ATPase ion transporters; (ii) translational, examining the kinetic behavior of gill Na+/K+-ATPase specific activity; and (iii) systemic, accompanying consequent adjustment of hemolymph osmolality. Palaemon northropi is an excellent hyper-hypo-osmoregulator in dilute and concentrated seawater, respectively. Macrobrachium acanthurus is a strong hyper-regulator in fresh water and hypo-regulates hemolymph osmolality and particularly [Cl−] in brackish water. Hemolymph hyper-regulation in fresh water (Macrobrachium acanthurus) and dilute seawater (Palaemon northropi) is underlain by augmented expression of both the gill Na+/K+-ATPase and V(H+)-ATPase. In contrast, in neither species is hypo-regulation sustained by changes in Na+/K+-ATPase mRNA expression levels, but rather by regulating enzyme specific activity. The integrated time course of Na+/K+- and V(H+)-ATPase expression and Na+/K+-ATPase activity in the gills of these palaemonid shrimps during acclimation to different salinities reveals versatility in their levels of regulation, and in the roles of these ion transporting pumps in sustaining processes of hyper- and hypo-osmotic and chloride regulation.

      PubDate: 2017-08-05T11:02:51Z
       
  • Behavioural, physiological and biochemical responses to aquatic hypoxia in
           the freshwater crayfish, Paranephrops zealandicus
    • Abstract: Publication date: Available online 27 July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Rebecca J. Broughton, Islay D. Marsden, Jonathan V. Hill, Chris N. Glover
      Hypoxia resulting from aquatic eutrophication threatens the population health of the New Zealand freshwater crayfish (koura), Paranephrops zealandicus. An integrated study, combining behavioural, physiological and biochemical approaches, was therefore conducted to characterise the tolerance of this species to hypoxia. When provided with a choice between water flows of high or low dissolved oxygen in short-term laboratory assays, crayfish did not preferentially inhabit waters of higher PO2. However, when an aerial refuge was provided and dissolved oxygen was progressively decreased, crayfish emersed at a PO2 of 0.56±0.03kPa, suggesting a relative high tolerance to hypoxia. Closed-box respirometry delineated a P crit, the point at which crayfish transition from oxyregulating to oxyconforming, of 6.0kPa. Simultaneous measurement of heart rate showed no changes across the PO2 range. In response to 6-h exposures to fixed dissolved oxygen levels (normoxia, 19.3kPa; moderate hypoxia, 3.5kPa; and severe hypoxia, 1.7kPa), P. zealandicus showed a haemolymph PO2 that declined with the magnitude of hypoxia, and while plasma pH declined in severe hypoxia, there were no changes in plasma PCO2. Plasma glucose concentrations fell, and plasma lactate increased in both hypoxic groups. There were no changes in tissue glucose or lactate concentrations. These data indicate that P. zealandicus is relatively tolerant of hypoxia, and possesses biochemical and physiological mechanisms that facilitate survival during short-term exposures to acute hypoxia. If hypoxia is severe and/or prolonged, then this species is capable of escaping to aerial refugia.

      PubDate: 2017-07-27T09:36:33Z
       
  • Heart rate variability reveals that a decrease in parasympathetic
           (‘rest-and-digest’) activity dominates autonomic stress responses in a
           free-living seabird
    • Abstract: Publication date: Available online 23 July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Martina S. Müller, Alexei L. Vyssotski, Maki Yamamoto, Ken Yoda
      The autonomic stress response, often referred to as the ‘fight-or-flight’ response, is a highly conserved physiological reaction to stress in vertebrates that occurs via a decrease in parasympathetic (PNS) activity, which promotes self-maintenance ‘rest and digest’ processes, and an increase in sympathetic (SNS) activity, which prepares an animal for danger (‘fight-or-flight’). Though the PNS and SNS both innervate most organs, they often control different tissues and functions within those organs (though the pacemaker of the heart is controlled by both). Moreover the PNS and SNS are regulated independently. Yet until now, most studies of autonomic stress responses in non-model species focused only on the SNS response. We used external electrocardiogram loggers to measure heart rate and heart rate variability indexes that reflect PNS and SNS activity in a seabird, the Streaked Shearwater (Calonectris leucomelas), during the stress of handling, and during recovery in the nest burrow or during restraint in a cloth bag. We show for the first time in a free-living animal that the autonomic stress response is mediated primarily by a rapid decrease in PNS activity: handling stress induced a large and long-lasting depression of PNS ‘rest-and-digest’ activity that required two hours to recover. We also found evidence for a substantially smaller and shorter-lasting SNS ‘fight-or-flight’ response. Confinement in a cloth bag was less stressful for birds than handling, but more stressful than recovering in nest burrows. We show that quantifying autonomic activity from heart rate variability is effective for non-invasively studying stress physiology in free-living animals.

      PubDate: 2017-07-27T09:36:33Z
       
  • The roles of metabolic thermogenesis in body fat regulation in striped
           hamsters fed high-fat diet at different temperatures
    • Abstract: Publication date: October 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 212
      Author(s): Lu-Lu Shi, Wei-Jia Fan, Ji-Ying Zhang, Xiao-Ya Zhao, Song Tan, Jing Wen, Jing Cao, Xue-Ying Zhang, Qing-Sheng Chi, De-Hua Wang, Zhi-Jun Zhao
      The metabolic thermogenesis plays important roles in thermoregulation, and it may be also involved in body fat regulation. The thermogenesis of brown adipose tissue (BAT) is largely affected by ambient temperature, but it is unclear if the roles in body fat regulation are dependent on the temperature. In the present study, uncoupling protein 1 (ucp1)-based BAT thermogenesis, energy budget and body fat content were examined in the striped hamsters fed high fat diet (HF) at cold (5°C) and warm (30°C) temperatures. The effect of 2, 4-dinitrophenol (DNP), a chemical uncoupler, on body fat was also examined. The striped hamsters showed a notable increase in body fat following the HF feeding at 21°C. The increased body fat was markedly elevated at 30°C, but was significantly attenuated at 5°C compared to that at 21°C. The hamsters significantly increased energy intake at 5°C, but consumed less food at 30°C relative to those at 21°C. Metabolic thermogenesis, indicated by basal metabolic rate, UCP1 expression and/or serum triiodothyronine levels, significantly increased at 5°C, but decreased at 30°C compared to that at 21°C. A significant decrease in body fat content was observed in DNP-treated hamsters relative to the controls. These findings suggest that the roles of metabolic thermogenesis in body fat regulation largely depend on ambient temperature. The cold-induced enhancement of BAT thermogenesis may contribute the decreased body fat, resulting in a lean mass. Instead, the attenuation of BAT thermogenesis at the warm may result in notable obesity.

      PubDate: 2017-07-21T09:12:34Z
       
  • The relationship between growth performance and metabolic rate flexibility
           varies with food availability in juvenile qingbo (Spinibarbus sinensis)
    • Abstract: Publication date: October 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 212
      Author(s): Ling-Qing Zeng, Lei Wang, Guan-Nan Wang, Yue Zeng, Shi-Jian Fu
      Phenotypic flexibility in traits can allow organisms to cope with environmental challenges. However, the ecological consequences (e.g., growth) of SMR flexibility in fish are poorly understood. Juvenile qingbo (Spinibarbus sinensis) were reared individually with two levels of food resources (satiation or limited) with either continuous feeding (CF) or starvation-refeeding (SR). In the CF experiment, SMR increased when individuals were fed either the satiation or limited diets, but no difference was found in average specific growth rate somatic growth (SGR) between the two food availabilities. The relationship between flexibility in SMR and SGR, feeding efficiency (FE) and food intake (FI) was positive in the satiation group but not in the limited food group. In the SR experiment, the initial SMR of individuals was negatively correlated with the SGR during starvation. During refeeding, the starved individuals increased both body mass and SMR under both food availabilities. Individuals with a greater increase in SMR were fed more and also had greater SGR and FE under the satiation diet, but these results were not observed under the limited diet. The average FE under the limited diet was greater than that under the satiation diet, causing there to be no significant difference in final body mass between the diet treatments at the end of refeeding. Our study suggested that SMR flexibility can allow individuals to maximize their potential growth performance in an environment with changing food availability, and the benefits from greater flexibility in SMR could be offset by their maintenance metabolism under environmental stress.

      PubDate: 2017-07-21T09:12:34Z
       
  • Glutamine protects intestinal calcium absorption against oxidative stress
           and apoptosis
    • Abstract: Publication date: Available online 19 July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Luciana Moine, Gabriela Díaz de Barboza, Adriana Pérez, Mercedes Benedetto, Nori Tolosa de Talamoni
      The aim of this study was to investigate whether glutamine (GLN) could block the inhibition of the intestinal Ca2+ absorption caused by menadione (MEN), and elucidate the underlying mechanisms. To do this, one-month old chicks were divided in four groups: 1) controls, 2) MEN treated, 3) GLN treated and 4) GLN treated before or after MEN treatment. Intestinal Ca2+ absorption as well as protein expression of molecules involved in the transcellular Ca2+ pathway were determined. Glutathione (GSH) and superoxide anion and activity of enzymes of the antioxidant system were evaluated. Apoptosis was measured by the TUNEL technique, the expression of FAS and FASL and the caspase-3 activity. A previous dose of 0.5g GLN/kg of b.w. was necessary to show its protector effect and a dose of 1g/kg of b.w. could restore the intestinal Ca2+ absorption after MEN treatment. GLN alone did not modify the protein expression of calbindin D28k and plasma membrane Ca2+-ATPase, but blocked the inhibitory effect of the quinone. GLN avoided changes in the intestinal redox state provoked by MEN such as a decrease in the GSH content, and increases in the superoxide anion and in the SOD and CAT activities. GLN abrogated apoptotic effects caused by MEN in intestinal mucosa, as indicated by the reduction of TUNEL (+) cells and the FAS/FASL/caspase-3 pathway. In conclusion, GLN could be an oral nutritional supplement to normalize the redox state and the proliferation/cell death ratio in the small intestine improving the intestinal Ca2+ absorption altered by oxidative stress.

      PubDate: 2017-07-21T09:12:34Z
       
  • Characterization of the FoxL2 proximal promoter and coding sequence from
           the common snapping turtle (Chelydra serpentina)
    • Abstract: Publication date: Available online 12 July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Lei Guo, Turk Rhen
      Sex is determined by temperature during embryogenesis in snapping turtles, Chelydra serpentina. Previous studies in this species show that dihydrotestosterone (DHT) induces ovarian development at temperatures that normally produce males or mixed sex ratios. The feminizing effect of DHT is associated with increased expression of FoxL2, suggesting that androgens regulate transcription of FoxL2. To test this hypothesis, we cloned the proximal promoter (1.6kb) and coding sequence for snapping turtle FoxL2 (tFoxL2) in frame with mCherry to produce a fluorescent reporter. The tFoxL2-mCherry fusion plasmid or mCherry control plasmid were stably transfected into mouse KK1 granulosa cells. These cells were then treated with 0, 1, 10, or 100nM DHT to assess androgen effects on tFoxL2-mCherry expression. In contrast to the main hypothesis, DHT did not alter expression of the tFoxL2-mCherry reporter. However, normal serum increased expression of tFoxL2-mCherry when compared to charcoal-stripped serum, indicating that the cloned region of tFoxL2 contains cis regulatory elements. We also used the tFoxL2-mCherry plasmid as an expression vector to test the hypothesis that DHT and tFoxL2 interact to regulate expression of endogenous genes in granulosa cells. While tFoxL2-mCherry and DHT had independent effects on mouse FoxL2, FshR, GnRHR, and StAR expression, tFoxL2-mCherry potentiated low concentration DHT effects on mouse aromatase expression. Further studies will be required to determine whether synergistic regulation of aromatase by DHT and FoxL2 also occurs in turtle gonads during the sex-determining period, which would explain the feminizing effect of DHT in this species.

      PubDate: 2017-07-21T09:12:34Z
       
  • Mitochondrial oxidative phosphorylation efficiency is upregulated during
           fasting in two major oxidative tissues of ducklings
    • Abstract: Publication date: October 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 212
      Author(s): Pierre-Axel Monternier, Loïc Teulier, Jocelyne Drai, Aurore Bourguignon, Delphine Collin-Chavagnac, Frédéric Hervant, Jean-Louis Rouanet, Damien Roussel
      Fasted endothermic vertebrates must develop physiological responses to maximize energy conservation and survival. The aim of this study was to determine the effect of 1-wk. fasting in 5-wk. old ducklings (Cairina moschata) from whole-body resting metabolic rate and body temperature to metabolic phenotype of tissues and mitochondrial coupling efficiency. At the level of whole organism, the mass-specific metabolic rate of ducklings was decreased by 40% after 1-wk. of fasting, which was associated with nocturnal Tb declines and shallow diurnal hypothermia during fasting. At the cellular level, fasting induced a large reduction in liver, gastrocnemius (oxidative) and pectoralis (glycolytic) muscle masses together with a fuel selection towards lipid oxidation and ketone body production in liver and a lower glycolytic phenotype in skeletal muscles. At the level of mitochondria, fasting induced a reduction of oxidative phosphorylation activities and an up-regulation of coupling efficiency (+30% on average) in liver and skeletal muscles. The present integrative study shows that energy conservation in fasted ducklings is mainly achieved by an overall reduction in mitochondrial activity and an increase in mitochondrial coupling efficiency, which would, in association with shallow hypothermia, increase the conservation of endogenous fuel stores during fasting.

      PubDate: 2017-07-11T02:40:38Z
       
  • The difficulty with correlations: Energy expenditure and brain mass in
           bats
    • Abstract: Publication date: October 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 212
      Author(s): Brian K. McNab, Meike Köhler
      Brain mass has been suggested to determine a mammal's energy expenditure. This potential dependence is examined in 48 species of bats. A correlation between characters may be direct or derived from shared correlations with intervening factors without a direct interaction. Basal rate of metabolism in these bats increases with brain mass: large brains are more expensive than small brains, and both brain mass and basal rate increase with body mass. Basal rate and brain mass also correlate with food habits in bats. Mass-independent basal rate weakly correlates with mass-independent brain mass, the correlation only accounting for 12% of the variation in basal rate, which disappears when the combined effects of body mass and food habits are deleted. The correlation between basal rate and brain mass seen in this and other studies usually accounts for <10% of the variation in basal rate and often <4%, even when statistically significant, a minimalist explanation for the level the basal rate. This correlation probably reflects the intermediacy of secondary factors, as occurred with food habits in bats. Most biological correlations are complicated and must be examined in detail before assurance can be given as to their bases.

      PubDate: 2017-07-11T02:40:38Z
       
  • Fish pigmentation and the melanocortin system
    • Abstract: Publication date: September 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 211
      Author(s): Laura Cal, Paula Suarez-Bregua, José Miguel Cerdá-Reverter, Ingo Braasch, Josep Rotllant
      The melanocortin system is a complex neuroendocrine signaling mechanism involved in numerous physiological processes in vertebrates, including pigmentation, steroidogenesis and metabolic control. This review focuses at one of its most fascinating function in fish, its regulatory role in the control of pigmentation, in which the melanocortin 1 receptor (Mc1r), its agonist α-melanocyte stimulating hormone (α-Msh), and the endogenous antagonist agouti signaling protein (Asip1) are the main players. Functional control of Mc1r, which is highly expressed in fish skin and whose activation stimulates melanin production and melanosome dispersion in fish melanophores, is considered a key mechanism for vertebrate pigment phenotypes. The α-Msh peptide, the most documented Mc1r agonist involved in pigmentation, is produced in the pituitary gland, activating melanin synthesis by binding to Mc1r in fish melanophores. Finally, Asip1 is the putative factor for establishing the evolutionarily conserved dorso-ventral pigment pattern found across vertebrates. However, we are just starting to understand how other melanocortin system components are acting in this complex regulatory network.

      PubDate: 2017-07-11T02:40:38Z
       
  • β1- and β2-adrenergic receptor stimulation differ in their effects on
           PGC-1α and atrogin-1/MAFbx gene expression in chick skeletal muscle
    • Abstract: Publication date: September 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 211
      Author(s): Saki Shimamoto, Daichi Ijiri, Mana Kawaguchi, Kazuki Nakashima, Osamu Tada, Hiroki Inoue, Akira Ohtsuka
      Adrenaline changes expression of the genes encoding peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1α), which is known as a regulator of muscle size, and atrogin-1/muscle atrophy F-box (MAFbx), which is a muscle-specific ubiquitin ligase. However, the subtype of β-adrenergic receptor (β-AR) involved in regulating these genes in skeletal muscle is not yet well defined. In this study, the effects of intraperitoneal injection of adrenaline and three β1–3-AR selective agonists on chick skeletal muscle metabolism were examined, to evaluate the functions of β-AR subtypes. Adrenaline decreased atrogin-1/MAFbx mRNA levels accompanied by an increase in PGC-1α mRNA and protein levels. However, among the three selective agonists, only the β1-AR agonist, dobutamine, increased PGC-1α mRNA and protein levels, while the β2-AR agonist, clenbuterol, suppressed atrogin-1/MAFbx mRNA levels. In addition, preinjection of the β1-AR antagonist, acebutolol, and the β2-AR antagonist, butoxamine, inhibited the adrenaline-induced increase in PGC-1α mRNA levels and the decrease in atrogin-1/MAFbx mRNA levels, respectively. Compared with adrenaline administration, the β3-AR agonist, BRL37344, decreased PGC-1α mRNA levels and increased atrogin-1/MAFbx mRNA levels. These results suggest that, in chick skeletal muscle, PGC-1α is induced via the β1-AR, while atrogin-1/MAFbx is suppressed via the β2-AR.

      PubDate: 2017-07-11T02:40:38Z
       
  • Distributional shift of urea production site from the extraembryonic yolk
           sac membrane to the embryonic liver during the development of cloudy
           catshark (Scyliorhinus torazame)
    • Abstract: Publication date: September 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 211
      Author(s): Wataru Takagi, Makiko Kajimura, Hironori Tanaka, Kumi Hasegawa, Shuntaro Ogawa, Susumu Hyodo
      Urea is an essential osmolyte for marine cartilaginous fishes. Adult elasmobranchs and holocephalans are known to actively produce urea in the liver, muscle and other extrahepatic organs; however, osmoregulatory mechanisms in the developing cartilaginous fish embryo with an undeveloped urea-producing organ are poorly understood. We recently described the contribution of extraembryonic yolk sac membranes (YSM) to embryonic urea synthesis during the early developmental period of the oviparous holocephalan elephant fish (Callorhinchus milii). In the present study, to test whether urea production in the YSM is a general phenomenon among oviparous Chondrichthyes, we investigated gene expression and activities of ornithine urea cycle (OUC) enzymes together with urea concentrations in embryos of the elasmobranch cloudy catshark (Scyliorhinus torazame). The intracapsular fluid, in which the catshark embryo develops, had a similar osmolality to seawater, and embryos maintained a high concentration of urea at levels similar to that of adult plasma throughout development. Relative mRNA expressions and activities of catshark OUC enzymes were significantly higher in YSM than in embryos until stage 32. Concomitant with the development of the embryonic liver, the expression levels and activities of OUC enzymes were markedly increased in the embryo from stage 33, while those of the YSM decreased from stage 32. The present study provides further evidence that the YSM contributes to embryonic urea homeostasis until the liver and other extrahepatic organs become fully functional, and that urea-producing tissue shifts from the YSM to the embryonic liver in the late developmental period of oviparous marine cartilaginous fishes.

      PubDate: 2017-07-11T02:40:38Z
       
  • Molecular markers of oocyte differentiation in European eel during
           hormonally induced oogenesis
    • Abstract: Publication date: September 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 211
      Author(s): Iratxe Rojo-Bartolomé, Leticia Martínez-Miguel, Anne-Gaëlle Lafont, M. Carmen Vílchez, Juan F. Asturiano, Luz Pérez, Ibon Cancio
      Reproduction in captivity is a key study issue in Anguilla anguilla as a possible solution for its dwindling population. Understanding the mechanisms controlling the production of ribosomal building blocks during artificially induced oocyte maturation could be particularly interesting. Transcription levels of ribosomal biogenesis associated genes could be used as markers to monitor oogenesis. Eels from the Albufera Lagoon were injected with carp pituitary extract for 15weeks and ovaries in previtellogenic (PV) stage (non-injected), in early-, mid-, late-vitellogenesis (EV, MV, LV), as well as in migratory nucleus stage (MN) were analysed. 5S rRNA and related genes were highly transcribed in ovaries with PV oocytes. As oocytes developed, transcriptional levels of genes related to 5S rRNA production (gtf3a), accumulation (gtf3a, 42sp43) and nucleocytoplasmic transport (rpl5, rpl11) and the 5S/18S rRNA index decreased (PV>EV>MV>LV>MN). On the contrary, 18S rRNA was at its highest at MN stage while ubtf1 in charge of activating RNA-polymerase I and synthesising 18S rRNA behaved as 5S related genes. Individuals that did not respond (NR) to the treatment showed 5S/18S index values similar to PV females, while studied genes showed EV/LV-like transcription levels. Therefore, NR females fail to express the largest rRNAs, which could thus be taken as markers of successful vitellogenesis progression. In conclusion, we have proved that the transcriptional dynamics of ribosomal genes provides useful tools to characterize induced ovarian development in European eels. In the future, such markers should be studied as putative indicators of response to hormonal treatments and of the quality of obtained eel oocytes.

      PubDate: 2017-07-11T02:40:38Z
       
  • Alpha-lipoic acid impairs body weight gain of young broiler chicks via
           modulating peripheral AMPK
    • Abstract: Publication date: September 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 211
      Author(s): Yufeng Wang, Nadia Everaert, Zhigang Song, Eddy Decuypere, Daniel Vermeulen, Johan Buyse
      In mammals, the AMP-activated protein kinase (AMPK) pathways in the central and peripheral tissues coordinately integrate inputs from multiple sources to regulate energy balance. The present study was aimed to explore the potential role of hepatic AMPK in the energy homeostasis of broiler chickens. Diets with 0, 0.05% or 0.1% alpha-lipoic acid (α-LA), a known AMPK inhibitor were provided to broiler chicks for 7days. As a result, α-LA supplementation decreased the relative growth rate of broiler chicks. Hepatic AMPKα2 mRNA levels were significantly upregulated by dietary α-LA, in concert with the increased phosphorylated AMPKα protein levels. In addition, hepatic FAS mRNA levels together with the malonyl-CoA to total CoA ester ratio were reduced by α-LA supplementation. Moreover, the hepatic phosphorylated glycogen synthase levels were increased resulting in a markedly decreased hepatic glycogen content. In conclusion, dietary α-LA supplementation decreased the in vivo hepatic glycogenesis and lipogenesis via stimulating hepatic AMPKα mRNA levels and the phosphorylated gene product. The stimulatory effect of α-LA on hepatic AMPK mRNA and pAMPKα protein levels together with our previous observations regarding its inhibitory effect on hypothalamic AMPK may have altered the energy balance and hence impaired body weight gain of broiler chicks.

      PubDate: 2017-07-11T02:40:38Z
       
  • Evidence of extensive plasma glucose recycling following a glucose load in
           seabass
    • Abstract: Publication date: September 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 211
      Author(s): João Rito, Ivan Viegas, Miguel A. Pardal, John G. Jones
      Seabass and other carnivorous fish are highly dependent on gluconeogenesis from dietary amino acids to maintain glycemia. Glucose recycling (glucose→C3-intermediate→glucose) may potentiate the effects of glucose administration in sparing amino acid gluconeogenesis. To date, very few measurements of glucose recycling have been reported in fish. Thus, to determine the extent of glucose recycling following a glycemic challenge, juvenile seabass were given an intraperitoneal glucose load (2gkg−1) enriched with [U-13C]glucose. 13C NMR analysis of plasma glucose 13C-isotopomers was used to determine the fractional contributions of glucose derived directly from the load versus that from glucose recycling at 48h after the load. Both fed and 21-day fasted fish (20 per condition) were studied. In fasted fish, 18±4% of plasma glucose was directly derived from the load while 13±2% was derived from glucose recycling. In fed fish, the load accounted for 6±1% of plasma glucose levels while glucose recycling contributed 16±4%. 13C NMR analysis of plasma lactate revealed 13C-isotopomers corresponding to the expected C3-intermediates of peripheral [U-13C]glucose catabolism indicating that circulating lactate was a key intermediate in glucose carbon recycling under these conditions. In conclusion, glucose recycling was shown to contribute a significant portion of plasma glucose levels in both fed and fasted seabass 48h after an intraperitoneal glucose challenge and circulating lactate was shown to be an intermediate of this pathway.

      PubDate: 2017-07-11T02:40:38Z
       
  • A high fat diet enhances the sensitivity of chick adipose tissue to the
           effects of centrally injected neuropeptide Y on gene expression of
           adipogenesis-associated factors
    • Abstract: Publication date: September 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 211
      Author(s): Guoqing Wang, Carli A. Williams, Betty R. McConn, Mark A. Cline, Elizabeth R. Gilbert
      The purpose of this study was to determine how dietary macronutrient composition and exogenous neuropeptide Y (NPY) affect mRNA abundance of factors associated with lipid metabolism in chick adipose tissue. Chicks were fed one of three isocaloric (3000kcal metabolizable energy (ME)/kg) diets after hatch: high carbohydrate (HC; control), high fat (HF; 30% of ME from soybean oil) or high protein (HP; 25% crude protein). On day 4 post-hatch, vehicle or 0.2nmol of NPY was injected intracerebroventricularly and abdominal and subcutaneous fat depots collected 1h later. In abdominal fat, mRNA abundance of peroxisome proliferator-activated receptor γ (PPARγ) and fatty acid binding protein 4 (FABP4) increased after NPY injection in HF diet-fed chicks. NPY injection decreased expression of PPARγ and sterol regulatory element-binding transcription factor 1 (SREBP1) in the subcutaneous fat of HC diet-fed chicks, whereas SREBP1 expression was increased in the subcutaneous fat of HF diet-fed chicks after NPY injection. An acutely increased central concentration of NPY in chicks affects adipose tissue physiology in a depot- and diet-dependent manner. The chick may serve as a model to understand the relationship between diet and the brain-fat axis' role in maintaining whole body energy homeostasis, as well as to understand metabolic distinctions among fat depots.

      PubDate: 2017-07-11T02:40:38Z
       
  • Uncoupling effect of palmitate is exacerbated in skeletal muscle
           mitochondria of sea-acclimatized king penguins (Aptenodytes patagonicus)
    • Abstract: Publication date: September 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 211
      Author(s): Benjamin Rey, Claude Duchamp, Damien Roussel
      In king penguin juveniles, the environmental transition from a terrestrial to a marine habitat, occurring at fledging, drastically stimulates lipid catabolism and the remodelling of muscle mitochondria to sustain extensive swimming activity and thermoregulation in the cold circumpolar oceans. However, the exact nature of these mechanisms remains only partially resolved. Here we investigated, in vitro, the uncoupling effect of increasing doses of fatty acids in pectoralis muscle intermyofibrillar mitochondria isolated, either from terrestrial never-immersed or experimentally cold water immersed pre-fledging king penguins or from sea-acclimatized fledged penguins. Mitochondria exhibited much greater palmitate-induced uncoupling respiration and higher maximal oxidative capacity after acclimatization to marine life. Such effects were not reproduced experimentally after repeated immersions in cold water, suggesting that the plasticity of mitochondrial characteristics may not be primarily driven by cold exposure per se but by other aspects of sea acclimatization.

      PubDate: 2017-07-11T02:40:38Z
       
  • The effects of hypoxia on active ionic transport processes in the gill
           epithelium of hyperregulating crab, Carcinus maneas
    • Abstract: Publication date: September 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 211
      Author(s): Čedomil Lucu, Andreas Ziegler
      Effects of hypoxia on the osmorespiratory functions of the posterior gills of the shore crab Carcinus maenas acclimated to 12ppt seawater (DSW) were studied. Short-circuit current (Isc) across the hemilamella (one epithelium layer supported by cuticle) was substantially reduced under exposure to 1.6, 2.0, or 2.5mg O2/L hypoxic saline (both sides of epithelium) and fully recovered after reoxygenation. Isc was reduced equally in the epithelium exposed to 1.6mg O2/L on both sides and when the apical side was oxygenated and the basolateral side solely exposed to hypoxia. Under 1.6mg O2/L, at the level of maximum inhibition of Isc, conductance was decreased from 40.0mScm−2 to 34.7mScm−2 and fully recovered after reoxygenation. Isc inhibition under hypoxia and reduced 86Rb+ (K+) fluxes across apically located K+ channels were caused preferentially by reversible inhibition of basolaterally located and ouabain sensitive Na+,K+-ATPase mediated electrogenic transport. Reversible inhibition of Isc is discussed as decline in active transport energy supply down regulating metabolic processes and saving energy during oxygen deprivation. In response to a 4day exposure of Carcinus to 2.0mg O2/L, hemolymph Na+ and Cl− concentration decreased, i.e. hyperosmoregulation was weakened. Variations of the oxygen concentration level and exposure time to hypoxia lead to an increase of the surface of mitochondria per epithelium area and might in part compensate for the decrease in oxygen availability under hypoxic conditions.

      PubDate: 2017-07-11T02:40:38Z
       
  • Developmental cardiovascular physiology of the olive ridley sea turtle
           (Lepidochelys olivacea)
    • Abstract: Publication date: September 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 211
      Author(s): Dane Alan Crossley, Janna Lee Crossley, Camilla Smith, Martha Harfush, Hermilo Sánchez-Sánchez, Mónica Vanessa Garduño-Paz, José Fernando Méndez-Sánchez
      Our understanding of reptilian cardiovascular development and regulation has increased substantially for two species the American alligator (Alligator mississippiensis) and the common snapping turtle (Chelydra serpentina) during the past two decades. However, what we know about cardiovascular maturation in many other species remains poorly understood or unknown. Embryonic sea turtles have been studied to understand the maturation of metabolic function, but these studies have not addressed the cardiovascular system. Although prior studies have been pivotal in characterizing development, and factors that influence it, the development of cardiovascular function, which supplies metabolic function, is unknown in sea turtles. During our investigation we focused on quantifying how cardiovascular morphological and functional parameters change, to provide basic knowledge of development in the olive ridley sea turtle (Lepidochelys olivacea). Embryonic mass, as well as mass of the heart, lungs, liver, kidney, and brain increased during turtle embryo development. Although heart rate was constant during this developmental period, arterial pressure approximately doubled. Further, while embryonic olive ridley sea turtles lacked cholinergic tone on heart rate, there was a pronounced beta adrenergic tone on heart rate that decreased in strength at 90% of incubation. This beta adrenergic tone may be partially originating from the sympathetic nervous system at 90% of incubation, with the majority originating from circulating catecholamines. Data indicates that olive ridley sea turtles share traits of embryonic functional cardiovascular maturation with the American alligator (Alligator mississippiensis) but not the common snapping turtle (Chelydra serpentina).

      PubDate: 2017-07-11T02:40:38Z
       
  • Sardine procalcitonin amino-terminal cleavage peptide has a different
           action from calcitonin and promotes osteoblastic activity in the scales of
           goldfish
    • Abstract: Publication date: September 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 211
      Author(s): Yoichi Kase, Takahiro Ikari, Toshio Sekiguchi, Masayuki Sato, Shouzo Ogiso, Tsuyoshi Kawada, Shin Matsubara, Honoo Satake, Yuichi Sasayama, Masato Endo, Kei-ichiro Kitamura, Atsuhiko Hattori, Takushi X. Watanabe, Yusuke Maruyama, Yoshinari Watanabe, Hisayuki Funahashi, Akira Kambegawa, Nobuo Suzuki
      The nucleotide sequence of a sardine preprocalcitonin precursor has been determined from their ultimobranchial glands in the present study. From our analysis of this sequence, we found that sardine procalcitonin was composed of procalcitonin amino-terminal cleavage peptide (N-proCT) (53 amino acids), CT (32 amino acids), and procalcitonin carboxyl-terminal cleavage peptide (C-proCT) (18 amino acids). As compared with C-proCT, N-proCT has been highly conserved among teleosts, reptiles, and birds, which suggests that N-proCT has some bioactivities. Therefore, both sardine N-proCT and sardine CT were synthesized, and their bioactivities for osteoblasts and osteoclasts were examined using our assay system with goldfish scales that consisted of osteoblasts and osteoclasts. As a result, sardine N-proCT (10−7 M) activated osteoblastic marker enzyme activity, while sardine CT did not change. On the other hand, sardine CT (10−9 to 10−7 M) suppressed osteoclastic marker enzyme activity, although sardine N-proCT did not influence enzyme activity. Furthermore, the mRNA expressions of osteoblastic markers such as type 1 collagen and osteocalcin were also promoted by sardine N-proCT (10−7 M) treatment; however, sardine CT did not influence their expressions. The osteoblastic effects of N-proCT lack agreement. In the present study, we can evaluate exactly the action for osteoblasts because our scale assay system is very sensitive and it is a co-culture system for osteoblasts and osteoclasts with calcified bone matrix. Both CT and N-proCT seem to influence osteoblasts and osteoclasts and promote bone formation by different actions in teleosts.

      PubDate: 2017-07-11T02:40:38Z
       
  • Changes in free amino acid content during naupliar development of the
           Calanoid copepod Acartia tonsa
    • Abstract: Publication date: August 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 210
      Author(s): Thomas Allan Rayner, Niels Ole Gerslev Jørgensen, Guillaume Drillet, Benni Winding Hansen
      Changes in free amino acids (FAA) were investigated in the potentially important live feed and neritic copepod species Acartia tonsa during naupliar development. Total content of FAA in A. tonsa nauplii was around 17% of dry weight at first development stage, and declined to 6% for later stages. Relative to body-volume and biomass, the FAA content indicated possible volume-dependent changes. However, changes in FAA with osmolytic activity could not account for this decline in FAA content, but suggests that the decline reflected degradation of residual FAAs from the embryonic stage. Glutamic acid revealed the largest change in relative abundance during naupliar development and declined from 29.0% at first nauplius stage to 7.1% at later stages. The high FAA pool in early naupliar stages may be necessary for naupliar development due to an absence of feeding at first development stages. The high FAA content in early nauplii indicates that A. tonsa is a valuable source for nutritional energy for first-feeding fish larvae and should be further exploited for aquaculture purposes. Enhancements to FAA abundances in nauplii through manipulation of maternal diets could be of future interest, as copepod nauplii can contain a substantial pool of FAAs at first development stage.

      PubDate: 2017-07-11T02:40:38Z
       
  • Life-history dependent relationships between body condition and immunity,
           between immunity indices in male Eurasian tree sparrows
    • Abstract: Publication date: August 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 210
      Author(s): Yuliang Zhao, Mo Li, Yanfeng Sun, Wei Wu, Guanqun Kou, Lingling Guo, Danning Xing, Yuefeng Wu, Dongming Li, Baohua Zhao
      In free-living animals, recent evidence indicates that innate, and acquired, immunity varies with annual variation in the demand for, and availability of, food resources. However, little is known about how animals adjust the relationships between immunity and body condition, and between innate and acquired immunity to optimize survival over winter and reproductive success during the breeding stage. Here, we measured indices of body condition (size-corrected mass [SCM], and hematocrit [Hct]), constitutive innate immunity (plasma total complement hemolysis activity [CH50]) and acquired immunity (plasma immunoglobulin A [IgA]), plus heterophil/lymphocyte (H/L) ratios, in male Eurasian tree sparrows (Passer montanus) during the wintering and the breeding stages. We found that birds during the wintering stage had higher IgA levels than those from the breeding stage. Two indices of body condition were both negatively correlated with plasma CH50 activities, and positively with IgA levels in wintering birds, but this was not the case in the breeding birds. However, there was no correlation between CH50 activities and IgA levels in both stages. These results suggest that the relationships between body condition and immunity can vary across life-history stage, and there are no correlations between innate and acquired immunity independent of life-history stage, in male Eurasian tree sparrows. Therefore, body condition indices predict immunological state, especially during the non-breeding stage, which can be useful indicators of individual immunocompetences for understanding the variations in innate and acquired immunity in free-living animals.

      PubDate: 2017-07-11T02:40:38Z
       
  • Neither artificial light at night, anthropogenic noise nor distance from
           roads are associated with oxidative status of nestlings in an urban
           population of songbirds
    • Abstract: Publication date: August 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 210
      Author(s): Giulia Casasole, Thomas Raap, David Costantini, Hamada AbdElgawad, Han Asard, Rianne Pinxten, Marcel Eens
      Increasing urbanization is responsible for road-related pollutants and causes an unprecedented increase in light and noise pollution, with potential detrimental effects for individual animals, communities and ecosystems. These stressors rarely act in isolation but studies dissecting the effects of these multiple stressors are lacking. Moreover, studies on urban stressors have mainly focused on adults, while exposure in early-life may be detrimental but is largely ignored. To fill this important knowledge gap, we studied if artificial light at night, anthropogenic noise and road-related pollution (using distance from roads as a proxy) explain variation in oxidative status in great tit nestlings (Parus major) in an urban population. Artificial light at night, anthropogenic noise and distance from roads were not associated with variation of the nine studied metrics of oxidative status (superoxide dismutase-SOD-, glutathione peroxidase-GPX, catalase-CAT-, non-enzymatic total antioxidant capacity-TAC-, reduced glutathione-GSH-, oxidized glutathione-GSSG-, ratio GSH/GSSG, protein carbonyls and thiobarbituric acid reactive substances-TBARS). Interestingly, for all oxidative status metrics, we found that there was more variation in oxidative status among individuals of the same nest compared to between different nests. We also showed an increase in protein carbonyls and a decrease of the ratio GSH/GSSG as the day advanced, and an increase of GPX when weather conditions deteriorated. Our study suggests that anthropogenic noise, artificial light at night and road-related pollution are not the most important sources of variation in oxidative status in great tit nestlings. It also highlights the importance of considering bleeding time and weather conditions in studies with free-living animals.

      PubDate: 2017-07-11T02:40:38Z
       
  • Metabolic costs of the mechanical components of the apparent specific
           dynamic action in the Dungeness crab, Cancer magister
    • Abstract: Publication date: August 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 210
      Author(s): Iain J. McGaw, Travis E. Van Leeuwen
      The specific dynamic action (SDA) describes the postprandial increase in metabolism. It is a composite of mechanical and chemical digestion, nutrient transport and protein synthesis. How these individual events contribute to the overall SDA has not been worked out fully for any organism. The mechanical events associated with the SDA were investigated in Dungeness crabs, Cancer magister. Following consumption of a meal, oxygen consumption (MO2) remained elevated for several hours. When the crabs were presented with fish scent there was a 2 fold increase in MO2, which rapidly decreased once the stimulus was removed. Crabs were then offered fish in a perforated tube. There was a rapid increase in MO2 associated with handling which returned to pre-treatment levels within an hour of removal of the tube. Finally the crabs were fed a piece of foam that had been soaked in fish water to determine the costs of mechanical digestion. The mechanical breakdown of the meal accounted for 29.9±3.3% of the overall SDA. Since food handling produced a large increase in MO2, it was reinvestigated using crabs that had one or both claws removed. Although there were no statistically significant differences as a function of claw removal there was a consistent trend in the data. The maximum MO2, scope, duration and SDA increased from animals with 0 claws through 1 claw to 2 claws. The results showed that the mechanical portion of the SDA can account for a significant portion of the overall budget in decapod crustaceans.

      PubDate: 2017-07-11T02:40:38Z
       
  • The central anorexigenic mechanism of amylin in Japanese quail (Coturnix
           japonica) involves pro-opiomelanocortin, calcitonin receptor, and the
           arcuate nucleus of the hypothalamus
    • Abstract: Publication date: August 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 210
      Author(s): Jingwei Yuan, Elizabeth R. Gilbert, Mark A. Cline
      Amylin is a 37-amino acid peptide hormone that exerts anorexigenic effects in humans and animals. We demonstrated that central injection of amylin into chicks affected feeding and related behaviors via the hypothalamus and brainstem, although the molecular mechanisms remained elusive. Thus, the objective of this study was to investigate the molecular mechanisms underlying anorexigenic effects of amylin in 7 day-old Japanese quail. Food but not water intake was reduced after intracerebroventricular amylin injection, and the behavior analysis indicated that this was associated with decreased food pecks and preening. Whole hypothalamus and hypothalamic nuclei including the arcuate nucleus (ARC), paraventricular nucleus (PVN), ventromedial hypothalamus (VMH), dorsomedial nucleus (DMN) and lateral hypothalamic area (LH) were extracted from quail at 1h post-injection for total RNA isolation. Real time PCR was performed to quantify mRNA abundance of amylin receptors, appetite-associated neuropeptides and monoamine-synthesis-related enzymes. Central amylin injection increased the mRNA abundance of calcitonin receptor (CALCR), receptor activity modifying protein 1 (RAMP1), pro-opiomelanocortin (POMC), and aromatic l-amino acid decarboxylase (AADC) in the hypothalamus and individual hypothalamic nuclei. Relative quantities of CALCR and POMC mRNA were greater in the ARC of the amylin- than vehicle-treated group. Thus, amylin-mediated effects on food intake may involve POMC, monoamine synthesis, and amylin receptor 1 (a complex of CALCR and RAMP1) in the ARC. Together, these data provide novel insights on the hypothalamic-specific molecular mechanisms of amylin-induced food intake.

      PubDate: 2017-07-11T02:40:38Z
       
  • Ecophysiological adaptations to variable salinity environments in the crab
           Hemigrapsus crenulatus from the Southeastern Pacific coast: Sodium
           regulation, respiration and excretion
    • Abstract: Publication date: August 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 210
      Author(s): Ángel Urzúa, Mauricio A. Urbina
      The estuarine crab Hemigrapsus crenulatus is a key benthic species of estuarine and intertidal ecosystems of the South Pacific, habitats that experience wide fluctuations in salinity. The physiological strategies that allow this crab to thrive under variable salinities, and how they change during the benthic stages of their life cycle, were evaluated under laboratory conditions. Oxygen consumption, ammonia excretion and the regulatory capacity of Na+ through the normal range of environmental salinities (i.e. 5, 10, 15, 20, 25, 30) were evaluated in three size classes, ranging from juveniles to adults. In all sizes, the oxygen consumption, ammonia excretion and regulatory capacity of Na+ decreased as salinity increased, with the highest values at 5 and the lowest values at 30 salinity. Bigger crabs showed a higher capacity to regulate Na+, as well as higher respiration and excretion rates compared to smaller crabs, suggesting that they are better equipped to exploit areas of the estuary with low salinity. Regardless of its size, H. crenulatus is a strong hyper regulator in diluted media (i.e. 5–20) while a conformer at salinities higher than 20. The regulatory capacity of Na+ was positively related with oxygen consumption and ammonia excretion rates. These relationships between sodium regulation, respiration and excretion are interpreted as adaptive physiological mechanisms that allow H. crenulatus to maintain the osmotic and bioenergetic balance over a wide range of environmental salinities.

      PubDate: 2017-07-11T02:40:38Z
       
  • Ovarian expression and localization of clathrin (Cltc) components in
           cutthroat trout, Oncorhynchus clarki: Evidence for Cltc involvement in
           endocytosis of vitellogenin during oocyte growth
    • Abstract: Publication date: Available online 4 July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Hiroko Mizuta, Yuji Mushirobira, Jun Nagata, Takashi Todo, Akihiko Hara, Benjamin J. Reading, Craig V. Sullivan, Naoshi Hiramatsu
      To evaluate potential involvement of clathrin in endocytosis of vitellogenin (Vtg) by teleost oocytes, cDNAs encoding clathrin heavy chain (cltc) were cloned from ovaries of cutthroat trout. Quantitative PCR revealed three types of cltc (cltc-a1, cltc-a2, cltc-b) to be expressed in 10 different tissues including the ovary. The cltc-a1 alone exhibited a significant decrease in ovarian expression during vitellogenesis; this was correlated with a corresponding decrease in transcripts encoding the major Vtg receptor (Vtgr). No development-related changes in ovarian cltc-a2 or cltc-b transcript levels were observed. In situ hybridization revealed a strong ctlc signal in pre-vitellogenic oocytes, but not in vitellogenic oocytes. Western blotting using a rabbit antiserum (a-Cltc) raised against a recombinant Cltc preparation detected a polypeptide band with an apparent mass of ~170kDa in vitellogenic ovary extracts. Immunohistochemistry using a-Cltc revealed Cltc to be uniformly distributed throughout the ooplasm of perinucleolus stage oocytes, translocated to the periphery of lipid droplet stage oocytes, and localized to the oolemma during vitellogenesis. These patterns of cltc/Cltc distribution and abundance during oogenesis, which are identical to those previously reported for vtgr/Vtgr in this species, constitute the first empirical evidence that cltc-a1/Cltc-a1 is involved in Vtg endocytosis via the Vtgr in teleost fish.

      PubDate: 2017-07-11T02:40:38Z
       
  • Characterization and spatiotemporal expression of gonadotropin-releasing
           hormone in the Pacific abalone, Haliotis discus hannai
    • Abstract: Publication date: July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 209
      Author(s): Tae Ha Kim, Mi Ae Kim, Kyeong Seop Kim, Jae Won Kim, Han Kyu Lim, Jung Sick Lee, Young Chang Sohn
      Gonadotropin-releasing hormone (GnRH) is a key neuropeptide regulating reproduction in humans and other vertebrates. Recently, GnRH-like cDNAs and peptides were reported in marine mollusks, implying that GnRH-mediated reproduction is an ancient neuroendocrine system that arose prior to the divergence of protostomes and deuterostomes. Here, we evaluated the reproductive control system mediated by GnRH in the Pacific abalone Haliotis discus hannai. We cloned a prepro-GnRH cDNA (Hdh-GnRH) from the pleural-pedal ganglion (PPG) in H. discus hannai, and analyzed its spatiotemporal gene expression pattern. The open reading frame of Hdh-GnRH encodes a protein of 101 amino acids, consisting of a signal peptide, a GnRH dodecapeptide, a cleavage site, and a GnRH-associated peptide. This structure and sequence are highly similar to GnRH-like peptides reported for mollusks and other invertebrates. Quantitative polymerase chain reaction demonstrated that Hdh-GnRH mRNA was more strongly expressed in the ganglions (PPG and cerebral ganglion [CG]) than in other tissues (gonads, gills, intestine, hemocytes, muscle, and mantle) in both sexes. In females, the expression levels of Hdh-GnRH mRNA in the PPG and branchial ganglion (BG) were significantly higher at the ripe and partial spent stages than at the early and late active stages. In males, Hdh-GnRH mRNA levels in the BG showed a significant increase in the partial spent stage. Unexpectedly, Hdh-GnRH levels in the CG were not significantly different among the examined stages in both sexes. These results suggest that Hdh-GnRH mRNA expression profiles in the BG and possibly the PPG are tightly correlated with abalone reproductive activities.

      PubDate: 2017-07-11T02:40:38Z
       
  • Stable isotope analysis of CO2 in breath indicates metabolic fuel shifts
           in torpid arctic ground squirrels
    • Abstract: Publication date: July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 209
      Author(s): Trixie N. Lee, Melanie M. Richter, Cory T. Williams, Øivind Tøien, Brian M. Barnes, Diane M. O'Brien, C. Loren Buck
      Stable carbon isotope ratios (δ13C) in breath show promise as an indicator of immediate metabolic fuel utilization in animals because tissue lipids have a lower δ13C value than carbohydrates and proteins. Metabolic fuel consumption is often estimated using the respiratory exchange ratio (RER), which has lipid and carbohydrate boundaries, but does not differentiate between protein and mixed fuel catabolism at intermediate values. Because lipids have relatively low δ13C values, measurements of stable carbon isotopes in breath may help distinguish between catabolism of protein and mixed fuel that includes lipid. We measured breath δ13C and RER concurrently in arctic ground squirrels (Urocitellus parryii) during steady-state torpor at ambient temperatures from −2 to −26°C. As predicted, we found a correlation between RER and breath δ13C values; however, the range of RER in this study did not reach intermediate levels to allow further resolution of metabolic substrate use with the addition of breath δ13C measurements. These data suggest that breath δ13C values are 1.1‰ lower than lipid tissue during pure lipid metabolism. From RER, we determined that arctic ground squirrels rely on nonlipid fuel sources for a significant portion of energy during torpor (up to 37%). The shift toward nonlipid fuel sources may be influenced by adiposity of the animals in addition to thermal challenge.

      PubDate: 2017-07-11T02:40:38Z
       
  • Similarity of osmoregulatory capacity in coastal and inland alligator gar
    • Abstract: Publication date: July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 209
      Author(s): Peter J. Allen, Alf Haukenes, Steve E. Lochmann
      The alligator gar Atractosteus spatula is a primitive fish species, occupying a wide range of temperature and salinity habitats. Long-distance movements are limited, leading to genetic differentiation between inland and coastal populations. Unknown is whether physiological capacity differs between geographically separated populations, particularly for traits important to osmoregulation in saline environments. Alligator gar from inland and coastal populations were reared in a similar environment and exposed to temperature (10, 30°C) and salinity (0, 20ppt) extremes to determine whether iono- and osmoregulatory ability differed between populations. There were few differences in osmoregulatory ability between populations, with similar gill, blood and gastrointestinal tract osmoregulatory parameters. Blood plasma osmolality, ion concentrations, intestinal pH and bicarbonate base concentrations, intestinal fluid osmolality, ion concentrations and gill Na+, K+-ATPase (NKA) activity were similar between populations. Notably, gar from both populations did not osmoregulate well at low temperature and high salinity, with elevated plasma osmolality and ion concentrations, low gill NKA, and little evidence of gastrointestinal tract contribution to ionic and base regulation based on a lack of intestinal fluid and low base content. Therefore, the hypothesis that coastal gar would have improved osmotic regulatory ability in saline environments as compared to inland alligator gar was not supported, suggesting physiological capacity may be retained in primitive species possibly due to its importance to their persistence through time.

      PubDate: 2017-07-11T02:40:38Z
       
  • Physiological and behavioral flexibility to an acute CO2 challenge, within
           and between genotypes in rainbow trout
    • Abstract: Publication date: July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 209
      Author(s): B. Sadoul, N.C. Friggens, C. Valotaire, L. Labbé, V. Colson, P. Prunet, I. Leguen
      Adaptive capacities, governing the ability of animals to cope with an environmental stressor, have been demonstrated to be strongly dependent upon genetic factors. Two isogenic lines of rainbow trout, previously described for their sensitivity and resilience to an acute confinement challenge, were used in the present study to investigate whether adaptive capacities remain consistent when fish are exposed to a different type of challenge. For this purpose, the effects of a 4-hour hypercapnia (CO2 increase) challenge at concentrations relevant in aquaculture conditions are described for the two isogenic lines. Oxygen consumption, cortisol release, group dispersion and group swimming activity were measured before, during and after the challenge. Sensitivity and resilience for each measure were extracted from temporal responses and analyzed using multivariate statistics. The two fish lines displayed significant differences in their cortisol response, translating differences in the stress axis sensitivity to the stressor. On the contrary, both lines showed, for other measures, similar temporal patterns across the study. Notable within line variability in the stress response was observed, despite identical genome between fish. The results are discussed in the context of animal robustness.

      PubDate: 2017-07-11T02:40:38Z
       
  • To stress or not to stress: Physiological responses to tetrodotoxin in
           resistant gartersnakes vary by sex
    • Abstract: Publication date: July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 209
      Author(s): Lorin A. Neuman-Lee, Edmund D. Brodie, Tyler Hansen, Edmund D. Brodie, Susannah S. French
      The activation of the hypothalamic pituitary adrenal (HPA) axis is one of the most important physiological processes in coping with any deviation in an organism's homeostasis. This activation and the secretion of glucocorticoids, such as corticosterone, allow organisms to cope with perturbations and return to optimal physiological functioning as quickly as possible. In this study, we examined the HPA axis activation in common gartersnakes (Thamnophis sirtalis) as a response to a natural toxin, tetrodotoxin (TTX). This neurotoxin is found in high levels in the Rough-skinned Newt (Taricha granulosa), which is a prey item for these snakes. To consume this toxic prey, these snakes have evolved variable resistance. We hypothesized that the more resistant individuals would show a lower HPA axis response than less resistant individuals, as measured by corticosterone (CORT) and bactericidal ability, which is a functional downstream measurement of CORT's activity. We determined “resistance level” for tetrodotoxin from each individual snake by determining the dose which reduced race speed by 50%. Individuals were injected them with an increasing amount of tetrodotoxin (10, 25, and 50 MAMUs) to determine this value. Thirty minutes after every injection, we gathered blood samples from each snake. Our results show that, while there were no significant differences among individual CORT levels in a dose-dependent manner, female snakes did have a larger stress response when compared to both males and juveniles. Different life-histories could explain why females were able to mount a higher HPA axis response. However, TTX had no downstream effects on bactericidal ability, although juveniles had consistently lower values than adults. Our research shows a possible dichotomy between how each sex manages tetrodotoxin and gives way for a more comprehensive analysis of tetrodotoxin in an ecological context.

      PubDate: 2017-07-11T02:40:38Z
       
  • When local anesthesia becomes universal: Pronounced systemic effects of
           subcutaneous lidocaine in bullfrogs (Lithobates catesbeianus)
    • Abstract: Publication date: July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 209
      Author(s): Catherine J.A. Williams, Aage K.O. Alstrup, Mads F. Bertelsen, Heidi M. Jensen, Cleo A.C. Leite, Tobias Wang
      Sodium channel blockers are commonly injected local anesthetics but are also routinely used for general immersion anesthesia in fish and amphibians. Here we report the effects of subcutaneous injection of lidocaine (5 or 50mgkg−1) in the hind limb of bullfrogs (Lithobates catesbeianus) on reflexes, gular respiration and heart rate (handled group, n =10) or blood pressure and heart rate via an arterial catheter (catheterized group n =6). 5mgkg−1 lidocaine did not cause loss of reflexes or change in heart rate in the handled group, but was associated with a reduction in gular respiratory rate (from 99±7 to 81±17breathsmin−1). 50mgkg−1 lidocaine caused a further reduction in respiratory rate to 59±15breathsmin−1, and led to a progressive loss of righting reflex (10/10 loss by 40min), palpebral reflex (9/10 loss at 70min), and contralateral toe pinch withdrawal (9/10 loss at 70min). Reflexes were regained over 4h. Systemic sedative effects were not coupled to local anti-nociception, as a forceps pinch test at the site of injection provoked movement at the height of the systemic effect (tested at 81±4min). Amphibians are routinely subject to general anesthesia via exposure to sodium channel blockers such as MS222 or benzocaine, however caution should be exercised when using local injectable lidocaine in amphibians, as it appears to dose-dependently cause sedation, without necessarily preventing local nociception for the duration of systemic effects.

      PubDate: 2017-07-11T02:40:38Z
       
  • Behavioral and physiological responses of yellow perch (Perca flavescens)
           to moderate hypoxia
    • Abstract: Publication date: July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 209
      Author(s): L. Zoe Almeida, Samuel C. Guffey, Maria S. Sepúlveda, Tomas O. Höök
      While severe hypoxia can be lethal and is usually avoided by mobile aquatic organisms, moderate hypoxic conditions are likely more prevalent and may affect organisms, such as fishes, in a variety of systems. However, fishes have the potential to adjust physiologically and behaviorally and thus reduce the negative effects of hypoxia. Quantifying such physiological responses may shed light on the ability of fishes to tolerate reduced oxygen concentrations. This study assessed how two different hatchery populations of yellow perch Perca flavescens, a fish that is likely to encounter moderate hypoxic conditions in a variety of systems, responded to moderate hypoxic exposure through three experiments: 1) a behavioral foraging experiment, 2) an acute exposure experiment, and 3) a chronic exposure experiment. No marked behavioral or physiological adjustments were observed in response to hypoxia (e.g., hemoglobin, feeding rate, movement frequency, gene expression did not change to a significant degree), possibly indicating a high tolerance level in this species. This may allow yellow perch to utilize areas of moderate hypoxia to continue foraging while avoiding predators that may be more sensitive to moderately low oxygen.

      PubDate: 2017-07-11T02:40:38Z
       
  • Chick subcutaneous and abdominal adipose tissue depots respond differently
           in lipolytic and adipogenic activity to α-melanocyte stimulating hormone
           (α-MSH)
    • Abstract: Publication date: July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 209
      Author(s): Steven L. Shipp, Guoqing Wang, Mark A. Cline, Elizabeth R. Gilbert
      In birds, α-MSH is anorexigenic, but effects on adipose tissue are unknown. Four day-old chicks were intraperitoneally injected with 0 (vehicle), 5, 10, or 50μg of α-MSH and subcutaneous and abdominal adipose tissue collected at 60min for RNA isolation (n =10). Plasma was collected post-euthanasia at 60 and 180min for measuring non-esterified fatty acids (NEFA) and α-MSH (n =10). Relative to the vehicle, food intake was reduced in the 50μg-treated group. Plasma NEFAs were greater in 10μg than vehicle-treated chicks at 3h. Plasma α-MSH was 3.06±0.57ng/ml. In subcutaneous tissue, melanocortin receptor 5 (MC5R) mRNA was increased in 10μg, MC2R and CCAAT-enhancer-binding protein β (C/EBPβ) mRNAs increased in 50μg, peroxisome proliferator-activated receptor γ and C/EBPα decreased in 5, 10 and 50μg, and Ki67 mRNA decreased in 50μg α-MSH-injected chicks, compared to vehicle-injected chicks. In abdominal tissue, adipose triglyceride lipase mRNA was greater in 10μg α-MSH- than vehicle-treated chicks. Cells isolated from abdominal fat that were treated with 10 and 100nM α-MSH for 4h expressed more MC5R and perilipin-1 than control cells (n =6). Cells that received 100nM α-MSH expressed more fatty acid binding protein 4 and comparative gene identification-58 mRNA than control cells. Glycerol-3-phosphate dehydrogenase (G3PDH) activity was greater in cells at 9days post-differentiation that were treated with 1 and 100nM α-MSH for 4h than in control cells (n =3). Results suggest that α-MSH increases lipolysis and reduces adipogenesis in adipose tissue.

      PubDate: 2017-07-11T02:40:38Z
       
  • Cross-tolerance effects due to adult heat hardening, desiccation and
           starvation acclimation of tropical drosophilid-Zaprionus indianus
    • Abstract: Publication date: July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 209
      Author(s): Bhawna Kalra, Aditya Moktan Tamang, Ravi Parkash
      Some insect taxa from polar or temperate habitats have shown cross-tolerance for multiple stressors but tropical insect taxa have received less attention. Accordingly, we considered adult flies of a tropical drosophilid-Zaprionus indianus for testing direct as well as cross-tolerance effects of rapid heat hardening (HH), desiccation acclimation (DA) and starvation acclimation (SA) after rearing under warmer and drier season specific simulated conditions. We observed significant direct acclimation effects of HH, DA and SA; and four cases of cross-tolerance effects but no cross-tolerance between desiccation and starvation. Cross-tolerance due to heat hardening on desiccation showed 20% higher effect than its reciprocal effect. There is greater reduction of water loss in heat hardened flies (due to increase in amount of cuticular lipids) as compared with desiccation acclimated flies. However, cross-tolerance effect of SA on heat knockdown was two times higher than its reciprocal. Heat hardened and desiccation acclimated adult flies showed substantial increase in the level of trehalose and proline while body lipids increased due to heat hardening or starvation acclimation. However, maximum increase in energy metabolites was stressor specific i.e. trehalose due to DA; proline due to HH and total body lipids due to SA. Rapid changes in energy metabolites due to heat hardening seem compensatory for possible depletion of trehalose and proline due to desiccation stress; and body lipids due to starvation stress. Thus, observed cross-tolerance effects in Z. indianus represent physiological changes to cope with multiple stressors related to warmer and drier subtropical habitats.

      PubDate: 2017-07-11T02:40:38Z
       
  • Doping for sex: Bad for mitochondrial performances' Case of
           testosterone supplemented Hyla arborea during the courtship period
    • Abstract: Publication date: July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 209
      Author(s): Julia L. Desprat, Loïc Teulier, Sara Puijalon, Adeline Dumet, Caroline Romestaing, Glenn J. Tattersall, Thierry Lengagne, Nathalie Mondy
      Sexual selection has been widely explored from numerous perspectives, including behavior, ecology, and to a lesser extent, energetics. Hormones, and specifically androgens such as testosterone, are known to trigger sexual behaviors. Their effects are therefore of interest during the breeding period. Our work investigates the effect of testosterone on the relationship between cellular bioenergetics and contractile properties of two skeletal muscles involved in sexual selection in tree frogs. Calling and locomotor abilities are considered evidence of good condition in Hyla males, and thus server as proxies for male quality and attractiveness. Therefore, how these behaviors are powered efficiently remains of both physiological and behavioral interest. Most previous research, however, has focused primarily on biomechanics, contractile properties or mitochondrial enzyme activities. Some have tried to establish a relationship between those parameters but to our knowledge, there is no study examining muscle fiber bioenergetics in Hyla arborea. Using chronic testosterone supplementation and through an integrative study combining fiber bioenergetics and contractile properties, we compared sexually dimorphic trunk muscles directly linked to chronic sound production to a hindlimb muscle (i.e. gastrocnemius) that is particularly adapted for explosive movement. As expected, trunk muscle bioenergetics were more affected by testosterone than gastrocnemius muscle. Our study also underlines contrasted energetic capacities between muscles, in line with contractile properties of these two different muscle phenotypes. The discrepancy of both substrate utilization and contractile properties is consistent with the specific role of each muscle and our results are elucidating another integrative example of a muscle force-endurance trade-off.

      PubDate: 2017-07-11T02:40:38Z
       
  • Effects of nutrient and water restriction on thermal tolerance: A test of
           mechanisms and hypotheses
    • Abstract: Publication date: Available online 1 July 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Katherine A. Mitchell, Leigh Boardman, Susana Clusella-Trullas, John S. Terblanche
      Nutritional deprivation or desiccation can influence thermal tolerance by impacting the insects' ability to evaporatively cool, maintain cell membrane integrity and conduct protective or repair processes. Recovery from chilling is also linked to the re-establishment of iono- and osmo-regulatory homeostasis. Here, using Mediterranean fruit fly (Ceratitis capitata, Diptera: Tephritidae), we manipulated water and nutrient availability to test the mechanistic expectation that changes in whole organism lipid and water content can elicit variation in cold or heat tolerance (scored as chill coma recovery time and heat knockdown time). We measured body condition (body water and lipid content) as well as heat shock protein 70 gene (hsp70) and protein (HSP70) levels. A significant reduction in body water content with water restriction did not translate into differences in chill coma recovery. When nutrient restriction was coupled with water deprivation, this resulted in a significant reduction (−54%) of heat knockdown time in females but male flies were unaffected. There was no evidence for an hsp70 or HSP70 response under any of the stress treatments and therefore no correlation with heat or cold tolerance. Heat hardening did decrease all hsp levels. Therefore, although body water and total body lipid content differed between the treatment groups, the contribution of these factors to thermal tolerance was inconsistent with mechanistic expectations in heat knockdown time and insignificant for chill coma recovery. These results therefore highlight that the effects of resource restriction on thermal limits in insects are mechanistically more complex than previous models of stress resistance have suggested.

      PubDate: 2017-07-11T02:40:38Z
       
  • The time enzyme in melatonin biosynthesis in fish: Day/night expressions
           of three aralkylamine N-acetyltransferase genes in three-spined
           stickleback
    • Abstract: Publication date: June 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 208
      Author(s): Ewa Kulczykowska, Agnieszka Kleszczyńska, Magdalena Gozdowska, Ewa Sokołowska
      In vertebrates, aralkylamine N-acetyltransferase (AANAT; EC 2.3.1.87) is a time-keeping enzyme in melatonin (Mel) biosynthesis. Uniquely in fish, there are several AANAT isozymes belonging to two AANAT subfamilies, AANAT1 and AANAT2, which are encoded by distinct genes. The different substrate preferences, kinetics and spatial expression patterns of isozymes indicate that they may have different functions. In the three-spined stickleback (Gasterosteus aculeatus), there are three genes encoding three AANAT isozymes. In this study, for the first time, the levels of aanat1a, aanat1b and aanat2 mRNAs are measured by absolute RT-qPCR in the brain, eye, skin, stomach, gut, heart and kidney collected at noon and midnight. Melatonin levels are analysed by HPLC with fluorescence detection in homogenates of the brain, eye, skin and kidney. The levels of aanats mRNAs differ significantly within and among organs. In the brain, eye, stomach and gut, there are day/night variations in aanats mRNAs levels. The highest levels of aanat1a and aanat1b mRNAs are in the eye. The extremely high expressions of these genes which are reflected in the highest Mel concentrations at this site at noon and midnight strongly suggest that the eye is an important source of the hormone in the three-spined sticklebacks. A very low level of aanat2 mRNA in all organs may suggest that AANAT1a and/or AANAT1b are principal isozymes in the three-spine sticklebacks. A presence of the isozymes of defined substrate preferences provides opportunity for control of acetylation of amines by modulation of individual aanat expression and permits the fine-tuning of indolethylamines and phenylethylamines metabolism to meet the particular needs of a given organ.

      PubDate: 2017-07-11T02:40:38Z
       
  • Evidence for two populations of hair bundles in the sea anemone,
           Nematostella vectensis
    • Abstract: Publication date: June 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 208
      Author(s): Shelcie S. Menard, Glen M. Watson
      Cytochalasin D (CD) was employed to disrupt F-actin within stereocilia of anemone hair bundles. CD treatment decreases the abundance of hair bundles (by 85%) while significantly impairing predation. The remaining hair bundles are ‘CD-resistant.’ Surprisingly, the morphology and F-actin content of resistant hair bundles are comparable to those of untreated controls. However, the resistant hair bundles fail to respond normally to the N-acetylated sugar, NANA, by elongating. Instead, they remain at resting length. Immediately after CD treatment, when only CD-resistant hair bundles are present, nematocyst discharge is normal into targets touched to tentacles in the absence of vibrations (i.e., baseline) but fails to increase normally in the presence of nearby vibrations at 56Hz, a key frequency. After CD treatment, the abundance of hair bundles recovers to control levels within three hours. At 2h after CD treatment, when CD-resistant and CD-sensitive hair bundles are both present, but a full-recovery is not yet complete, somewhat enhanced discharge of nematocysts occurs into targets touched to tentacles in the presence of nearby vibrations at 56Hz (at least as compared to the response of CD-treated animals to contact with test probes in the absence of vibrations). Additionally, at 2h after CD-treatment, prey capture recovers to normal. Thus, two populations of hair bundles may be present on tentacles of sea anemones: those that are CD-resistant and those that are CD-sensitive. The functions of these hair bundles may be distinct.

      PubDate: 2017-07-11T02:40:38Z
       
  • Feather corticosterone during non-breeding correlates with multiple
           measures of physiology during subsequent breeding in a migratory seabird
    • Abstract: Publication date: Available online 24 February 2017
      Source:Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
      Author(s): Graham D. Fairhurst, Louise Champoux, Keith A. Hobson, Jean-François Rail, Jonathan Verreault, Magella Guillemette, William A. Montevecchi, Pauline Brousseau, Catherine Soos
      Carry-over effects in migratory birds are likely mediated by physiological processes that are activated in response to environmental variation. Such processes affect body condition and/or reproductive success, and can include corticosterone (CORT) because this hormone responds to environmental stressors and influences energy balance. Few studies have considered how CORT levels during non-breeding relate to a broader physiological profile during subsequent breeding, and fewer still have considered measures other than body condition. To explore CORT's potential role in carry-over effects, we investigated the relationship between CORT and foraging ecology of northern gannets (Morus bassanus) during the non-breeding period, and tested for associations between these factors and variation in a suite of physiological and biochemical metrics during subsequent breeding. Northern gannets are the largest seabird top predator in the North Atlantic and were among the hardest hit by the Deepwater Horizon oil blowout in the Gulf of Mexico in 2010. We used light-level geolocators to confirm winter origins of individuals in our study. No interrelationships were found among levels of CORT from feathers grown during non-breeding (CORTf) and variation in foraging ecology, measured by stable isotopes of carbon (δ13C) and nitrogen (δ15N) from the same feathers. CORTf was correlated negatively with hematocrit and positively with triglyceride measured during subsequent incubation, and explained more variation in these variables than did body mass during incubation. These findings provide support for the hypothesis that energy management, measured using CORTf, during non-breeding carries over to influence physiological measures other than body condition. Gannets that previously wintered within the Gulf of Mexico in the years following the Deepwater Horizon oil blowout had higher levels of CORTf compared to birds that wintered along the Atlantic coast, suggesting an increased energetic cost associated with visiting the Gulf of Mexico. Our results indicate that CORT during non-breeding is associated with a broader physiological profile during subsequent breeding than previously reported in birds.

      PubDate: 2017-03-03T06:11:06Z
       
 
 
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