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Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology

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https://read.qxmd.com/read/31104080/pheomelanin-synthesis-varies-with-protein-food-abundance-in-developing-goshawks
#1
Ismael Galván, Alberto Jorge, Jan T Nielsen, Anders P Møller
The accumulation of the amino acid cysteine in lysosomes produces toxic substances, which are avoided by a gene (CTNS) coding for a transporter that pumps cystine out of lysosomes. Melanosomes are lysosome-related organelles that synthesize melanins, the most widespread pigments in animals. The synthesis of the orange melanin, termed pheomelanin, depends on cysteine levels because the sulfhydryl group is used to form the pigment. Pheomelanin synthesis may, therefore, be affected by cysteine homeostasis, although this has never been explored in a natural system...
May 18, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/31101978/effect-of-protein-synthesis-inhibitor-cycloheximide-on-starvation-fasting-and-feeding-oxygen-consumption-in-juvenile-spiny-lobster-sagmariasus-verreauxi
#2
Shuangyao Wang, Quinn P Fitzgibbon, Chris G Carter, Gregory G Smith
Metabolism in aquatic ectotherms evaluated by oxygen consumption rates reflects energetic costs including those associated with protein synthesis. Metabolism is influenced by nutritional status governed by feeding, nutrient intake and quality, and time without food. However, little is understood about contribution of protein synthesis to crustacean energy metabolism. This study is the first using a protein synthesis inhibitor cycloheximide to research contribution of cycloheximide-sensitive protein synthesis to decapod crustacean metabolism...
May 17, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/31076837/within-winter-flexibility-in-muscle-and-heart-lipid-transport-and-catabolism-in-passerine-birds
#3
David L Swanson, Marisa O King, William Culver, Yufeng Zhang
Small birds in cold climates may show within-winter metabolic flexibility to match metabolic capacities to prevailing weather conditions. This flexibility may occur over periods of days to weeks, but the underlying mechanisms for such flexibility are not well understood. Because lipids are the primary fuel for sustained thermogenesis, we examined whether lipid transport and catabolism can mediate within-winter metabolic flexibility in two small temperate-zone wintering passerine birds, dark-eyed juncos (Junco hyemalis) and house sparrows (Passer domesticus)...
May 10, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/31073767/effects-of-short-and-long-term-cold-acclimation-on-morphology-physiology-and-exercise-performance-of-california-mice-peromyscus-californicus-potential-modulation-by-fatherhood
#4
Jacob R Andrew, Theodore Garland, Mark A Chappell, Meng Zhao, Wendy Saltzman
California mice (Peromyscus californicus) differ from most other mammals in that they are biparental, genetically monogamous, and (compared with other Peromyscus) relatively large. We evaluated effects of cold acclimation on metabolic rate, exercise performance, and morphology of pair-housed male California mice, as well as modulation of these effects by fatherhood. In Experiment 1, virgin males housed at 5° or 10 °C for approximately 25 days were compared with virgins housed at standard vivarium temperature of 22 °C...
May 9, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30953127/vitellogenesis-in-spiders-first-analysis-of-protein-changes-in-different-reproductive-stages-of-polybetes-pythagoricus
#5
S Romero, A Laino, F Arrighetti, C F García, M Cunningham
Vitellogenesis represents one of the most vital processes of oviparous species during which various proteins, carbohydrates, and lipids are synthesized and stored inside the developing oocytes. Through analyzing protein changes in the midgut diverticula, hemolymph, and ovaries of females throughout the different vitellogenic stages of the spider Polybetes pythagoricus, we determined the origin of the different proteins involved in the formation of lipovitellins (LVs) along with the existence of a linkage between the hemocyanin and this vital process...
April 5, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30949759/molecular-basis-of-the-digestive-functionality-in-developing-persian-sturgeon-acipenser-persicus-larvae-additional-clues-for-its-phylogenetic-status
#6
Neda Gilannejad, Fatemeh Paykan Heyrati, Salar Dorafshan, Juan Antonio Martos-Sitcha, Manuel Yúfera, Gonzalo Martínez-Rodríguez
Persian sturgeon (Acipenser persicus) is a critically endangered species, mainly due to overexploitation for its caviar. The permanence of populations of this species in the Caspian Sea is fully dependent on restocking programs. Accordingly, it is considered as an interesting target for aquaculture for both restocking and commercial purposes. In addition, as a Chondrostei, it exhibits one of the slowest rates of molecular evolution among vertebrates and is propounded as an excellent candidate for phylogenetic analysis and evolutionary biology...
April 4, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30941501/intertidal-triplefin-fishes-have-a-lower-critical-oxygen-tension-p-crit-higher-maximal-aerobic-capacity-and-higher-tissue-glycogen-stores-than-their-subtidal-counterparts
#7
Tristan J McArley, Anthony J R Hickey, Lisa Wallace, Andreas Kunzmann, Neill A Herbert
Decreased oxygen (O2 ) availability (hypoxia) is common in rock pools and challenges the aerobic metabolism of fishes living in these habitats. In this study, the critical O2 tension (Pcrit ), a whole animal measure of the aerobic contribution to hypoxia tolerance, was compared between four New Zealand triplefin fishes including an intertidal specialist (Bellapiscis medius), an occasional intertidal inhabitant (Forsterygion lapillum) and two exclusively subtidal species (F. varium and F. malcolmi). The intertidal species had lower Pcrit values than the subtidal species indicating traits to meet resting O2 demands at lower O2 tensions...
April 2, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30923894/from-ice-to-ocean-changes-in-the-thermal-function-of-harp-seal-pelt-with-ontogeny
#8
Linnea E Pearson, Emma L Weitzner, Jennifer M Burns, Mike O Hammill, Heather E M Liwanag
Many animals exhibit ontogenetic changes associated with adaptations for survival. Harp seals (Pagophilus groenlandicus) live in the Arctic and rely on thick insulation to maintain thermal homeostasis. Adult harp seals primarily use blubber for insulation, but newborn harp seals rely on a lanugo pelt while nursing, as their blubber layer develops and their first-year pelage grows. This study compared ontogenetic changes in the thermal properties of harp seal pelts in water and in air. Thermal conductivity, pelt thickness, and thermal resistance were measured in water for pelts of harp seal neonates (1 day old), thin whitecoats (4 day old), fat whitecoats (9 day old), ragged jackets (2 week old), beaters (3 week old), and adults and compared to previously published measurements made on the same pelts in air...
March 28, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30874900/an-intertidal-fish-shows-thermal-acclimation-despite-living-in-a-rapidly-fluctuating-environment
#9
Carmen Rose Burke da Silva, Cynthia Riginos, Robbie Stuart Wilson
The co-evolution of acclimation capacity and thermal performance breadth has been a contentious issue for decades, and little is known regarding the extent to which acclimation alters the shape of acute thermal performance curves. Current acclimation theory suggests that when daily variation is large and unpredictable ectotherms should not acclimate but should evolve wide performance breadths, allowing maintenance of performance across a wide thermal range. The subtropical intertidal zone, however, experiences a large amount of daily thermal variation, but daily means and ranges shift in predictable ways with season, where daily and seasonal variation is roughly equal...
March 14, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30874899/moult-related-reduction-of-aerobic-scope-in-passerine-birds
#10
William A Buttemer, Silke Bauer, Tamara Emmenegger, Dimitar Dimitrov, Strahil Peev, Steffen Hahn
It is well established that the nutrient and energy requirements of birds increase substantially during moult, but it is not known if these increased demands affect their aerobic capacity. We quantified the absolute aerobic scope of house and Spanish sparrows, Passer domesticus and P. hispaniolensis, respectively, before and during sequential stages of their moult period. The absolute aerobic scope (AAS) is the difference between maximum metabolic rate (MMR) during peak locomotor activities and minimum resting metabolic rate (RMRmin ), thus representing the amount of aerobic power above that committed to maintenance needs available for other activities...
March 14, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30848340/antioxidant-capacity-is-repeatable-across-years-but-does-not-consistently-correlate-with-a-marker-of-peroxidation-in-a-free-living-passerine-bird
#11
Charlotte Récapet, Mathilde Arrivé, Blandine Doligez, Pierre Bize
Oxidative stress occurs when reactive oxygen species (ROS) exceed antioxidant defences, which can have deleterious effects on cell function, health and survival. Therefore, organisms are expected to finely regulate pro-oxidant and antioxidant processes. ROS are mainly produced through aerobic metabolism and vary in response to changes in energetic requirements, whereas antioxidants may be enhanced, depleted or show no changes in response to changes in ROS levels. We investigated the repeatability, within-individual variation and correlation across different conditions of two plasmatic markers of the oxidative balance in 1108 samples from 635 free-living adult collared flycatchers (Ficedula albicollis)...
March 8, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30810797/a-high-fat-diet-impacts-memory-and-gene-expression-of-the-head-in-mated-female-drosophila-melanogaster
#12
Osvaldo Rivera, Lara McHan, Bridget Konadu, Sumitkumar Patel, Silvienne Sint Jago, Matthew E Talbert
Obesity predisposes humans to a range of life-threatening comorbidities, including type 2 diabetes and cardiovascular disease. Obesity also aggravates neural pathologies, such as Alzheimer's disease, but this class of comorbidity is less understood. When Drosophila melanogaster (flies) are exposed to high-fat diet (HFD) by supplementing a standard medium with coconut oil, they adopt an obese phenotype of decreased lifespan, increased triglyceride storage, and hindered climbing ability. The latter development has been previously regarded as a potential indicator of neurological decline in fly models of neurodegenerative disease...
February 27, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30805750/interactions-between-humidity-and-evaporative-heat-dissipation-in-a-passerine-bird
#13
Monique van Dyk, Matthew J Noakes, Andrew E McKechnie
Environmental humidity is thought to be a major determinant of evaporative cooling capacity at high air temperatures (Ta ), but the technical challenges of experimentally manipulating humidity in respirometry chambers have resulted in far less being known about the effects of humidity compared to those of Ta . We tested the prediction that at Ta approaching and exceeding normothermic body temperature (Tb ), high humidity would result in higher Tb , lower evaporative water loss (EWL) and/or higher resting metabolic rate (RMR) in a passerine bird, the white-browed sparrow-weaver (Plocepasser mahali)...
February 25, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30631901/purification-and-characterization-of-a-urea-sensitive-lactate-dehydrogenase-from-skeletal-muscle-of-the-african-clawed-frog-xenopus-laevis
#14
Christine L Childers, Kenneth B Storey
The African clawed frog, Xenopus laevis endures whole body dehydration which can increase its reliance on anaerobic glycolysis for energy production. This makes the regulation of the terminal enzyme of glycolysis, lactate dehydrogenase (LDH), crucial to stress survival. We investigated the enzymatic properties and posttranslational modification state of purified LDH from the skeletal muscle of control and dehydrated (30% total body water loss) X. laevis. LDH from the muscle of dehydrated frogs showed a 93% reduction in phosphorylation on threonine residues and an 80% reduction of protein nitrosylation...
April 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30739144/physical-chemical-and-functional-properties-of-neuronal-membranes-vary-between-species-of-antarctic-notothenioids-differing-in-thermal-tolerance
#15
Amanda M Biederman, Donald E Kuhn, Kristin M O'Brien, Elizabeth L Crockett
Disruption of neuronal function is likely to influence limits to thermal tolerance. We hypothesized that with acute warming the structure and function of neuronal membranes in the Antarctic notothenioid fish Chaenocephalus aceratus are more vulnerable to perturbation than membranes in the more thermotolerant notothenioid Notothenia coriiceps. Fluidity was quantified in synaptic membranes, mitochondrial membranes, and myelin from brains of both species of Antarctic fishes. Polar lipid compositions and cholesterol contents were analyzed in myelin; cholesterol was measured in synaptic membranes...
February 9, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30725175/contractile-function-of-the-excised-hagfish-heart-during-anoxia-exposure
#16
L A Gatrell, E Farhat, W G Pyle, Todd E Gillis
Pacific hagfish, Eptatretus stoutii, can recover from 36 h of anoxia and their systemic hearts continue to work throughout the exposure. Recent work demonstrates that glycogen stores are utilized in the E. stoutii heart during anoxia but that these are not sufficient to support the measured rate of ATP production. One metabolic fuel that could supplement glycogen during anoxia is glycerol. This substrate can be derived from lipid stores, stored in the heart, or delivered via the blood. The purpose of this study was to determine the effect of glycerol on the contractile function of the excised E...
February 6, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30725174/ventilatory-metabolic-and-thermoregulatory-responses-of-damaraland-mole-rats-to-acute-and-chronic-hypoxia
#17
Sarah Y Zhang, Matthew E Pamenter
Damaraland and naked mole rats are the only eusocial mammalian species and live in densely populated, poorly ventilated underground burrows, within which they likely experience intermittent periods of hypoxia. Naked mole rats are the most hypoxia-tolerant mammal and do not exhibit a hypoxic ventilatory response to acute or chronic hypoxia but instead rely upon a robust hypoxic metabolic response to tolerate reduced environmental O2 . Conversely, physiological responses to hypoxia have not been explored in Damaraland mole rats but given their social and environmental similarities to naked mole rats, we hypothesized that they would exhibit similar physiological responses to hypoxia...
February 6, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30719532/energetics-and-thermal-adaptation-in-semifossorial-pine-voles-microtus-lusitanicus-and-microtus-duodecimcostatus
#18
Rita I Monarca, John R Speakman, Maria da Luz Mathias
Rodents colonising subterranean environments have developed several morphological, physiological and behaviour traits that promote the success of individuals in such demanding conditions. Resting metabolic rate, thermoregulation capacity and daily energy expenditure were analysed in two semi-fossorial pine-vole species Microtus lusitanicus and Microtus duodecimcostatus inhabiting distinct areas of the Iberian Peninsula. Individuals capture location varied in habitat and soil features, allowing the comparison of energetic parameters with ecological characteristics, that can help explain the use of the subterranean environment and dependence of the burrow system...
February 4, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30719531/hydrogen-sulphide-toxicity-and-the-importance-of-amphibious-behaviour-in-a-mangrove-fish-inhabiting-sulphide-rich-habitats
#19
Paige V Cochrane, Giulia S Rossi, Louise Tunnah, Michael G Jonz, Patricia A Wright
We investigated amphibious behaviour, hydrogen sulphide (H2 S) tolerance, and the mechanism of H2 S toxicity in the amphibious mangrove rivulus (Kryptolebias marmoratus). We found that fish emersed (left water) in response to acutely elevated [H2 S] (~ 130-200 µmol l-1 ). The emersion response to H2 S may be influenced by prior acclimation history due to acclimation-induced alterations in gill morphology and/or the density and size of neuroepithelial cells (NECs) on the gills and skin. Thus, we acclimated fish to water (control), H2 S-rich water, or air and tested the hypotheses that acclimation history influences H2 S sensitivity due to acclimation-induced changes in (i) gill surface area and/or (ii) NEC density and/or size...
February 4, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://read.qxmd.com/read/30603846/effects-of-thyroid-hormones-and-cold-acclimation-on-the-energy-metabolism-of-the-striped-hamster-cricetulus-barabensis
#20
Jing Wen, Qing-Gang Qiao, Zhi-Jun Zhao, De-Hua Wang, Wei-Hong Zheng, Zuo-Xin Wang, Jin-Song Liu
To examine the effects of low ambient temperature and thyroid hormones on the energy metabolism of the striped hamster (Cricetulus barabensis), adult male striped hamsters were kept at 30 °C, or acclimated to 5 °C, for 4 weeks. During this time, hamsters were treated with a synthetic thyroxine, levothyroxine sodium (LTS), the antithyroid drug methimazole, or saline solution (control). Hamster's food intake, basal metabolic rate (BMR), non-shivering thermogenesis (NST), thyroid hormones, body fat content, mitochondrial state-4 respiration, cytochrome c oxidase, and uncoupling protein 1 (UCP1) gene expression in brown adipose tissue (BAT), were measured...
February 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
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