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

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https://www.readbyqxmd.com/read/30008138/ocean-acidification-effects-of-ph-on-45-ca-uptake-by-lobster-branchiostegites
#1
Lilian Nagle, Skye Brown, Arianna Krinos, Gregory A Ahearn
Gill chambers of the Atlantic lobster, Homarus americanus, possess three structures that are involved with respiration and ion regulation: gill filaments, epipodites, and branchiostegites. This paper describes ion transport mechanisms present in the plasma membranes of branchiostegite epithelial cells and the effects of pH on the uptake of 45 Ca by these processes. Partially purified membrane vesicles (PPMV) of branchiostegite cells were produced by a homogenization/centrifugation method that has previously been used to define ion transport processes in both crab and lobster gill tissues...
July 14, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/30008137/savanna-elephants-maintain-homeothermy-under-african-heat
#2
Michael A Mole, Shaun Rodrigues DÁraujo, Rudi J van Aarde, Duncan Mitchell, Andrea Fuller
To conserve body water, mammals may reduce evaporative water loss by storing heat, allowing core body temperature to rise more than usual during the day, and to fall more than usual during the cooler night, so demonstrating heterothermy. It has been proposed that elephants are heterothermic, but body temperature never has been measured in elephants over 24 h at environmental temperatures higher than body temperature, where elephants would have to rely on evaporative cooling to maintain homeothermy. We used ingested temperature data loggers to record core temperature of four partly free-ranging savanna elephants exposed to high solar radiation and environmental temperatures that exceeded core temperature (> 36 °C) in their natural habitat...
July 14, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/30008136/species-specific-low-plasma-glucose-in-fish-is-associated-with-relatively-high-tissue-glucose-content-and-is-inversely-correlated-with-cardiac-glycogen-content
#3
Connie E Short, William R Driedzic
The relationship between plasma glucose concentration and intracellular glucose (liver, heart, brain, gill, gonad, intestine, kidney, spleen, white muscle) was determined in fish species with a range in plasma glucose (Atlantic cod, 5.06 mM; cunner, 3.8 mM; rainbow trout, 3.7 mM; lumpfish, 0.9 mM; short-horned sculpin, 0.6 mM; and winter flounder, 0.6 mM). The ratio of intracellular glucose/plasma glucose was always higher than one in liver for all species consistent with a diffusion gradient from the tissue to the plasma...
July 14, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29948161/physiological-protective-action-of-dissolved-organic-carbon-on-ion-regulation-and-nitrogenous-waste-excretion-of-zebrafish-danio-rerio-exposed-to-low-ph-in-ion-poor-water
#4
Rafael M Duarte, Chris M Wood, Adalberto L Val, D Scott Smith
Dissolved organic carbon (DOC) represents a heterogeneous group of naturally-occurring molecules in aquatic environments, and recent studies have evidenced that optically dark DOCs can exert some positive effects on ionoregulatory homeostasis of aquatic organisms in acidic waters. We investigated the effects of Luther Marsh DOC, a dark allochthonous DOC, on ion regulation and N-waste excretion of zebrafish acutely exposed to either neutral or low pH in ion-poor water. In the first experiment, simultaneous exposure to pH 4...
June 11, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29948160/effects-of-ocean-acidification-and-salinity-variations-on-the-physiology-of-osmoregulating-and-osmoconforming-crustaceans
#5
Andressa Cristina Ramaglia, Leandro Mantovani de Castro, Alessandra Augusto
Survival, osmoregulatory pattern, oxygen consumption, energy spent on metabolism, ammonia excretion, type of oxidized energy substrate, and hepatosomatic index were evaluated in decapods (an osmoregulating crab, Callinectes danae, and an osmoconforming seabob shrimp, Xiphopenaeus kroyeri) exposed to carbon dioxide-induced water acidification (pH 7.3, control pH 8.0) and different salinities (20, 25, 30, 35, and 40‰) for 3 days. Compared to the animals kept at controlled pH, exposure to reduced pH resulted in the loss of osmoregulatory capacity in C...
June 11, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29948159/thyroid-hormone-manipulation-influences-development-of-cardiovascular-regulation-in-embryonic-pekin-duck-anas-platyrhynchos-domestica
#6
Tushar S Sirsat, Dane A Crossley, Janna L Crossley, Edward M Dzialowski
Thyroid hormones are key regulators of avian metabolism and may play a significant role in development at hatching. To better understand the role of thyroid hormones in avian development, we examined autonomic control of heart rate and blood pressure while manipulating thyroid hormone levels in the late stage embryonic Pekin duck (Anas platyrhynchos domestica). Thyroid hormone levels were manipulated on day 24 of a 28-day incubation period with the thyroperoxidase inhibitor methimazole (MMI), triiodothyronine (T3 ), or saline...
June 8, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29948158/protective-effects-of-compatible-solute-ectoine-against-ethanol-induced-toxic-alterations-in-daphnia-magna
#7
Adam Bownik, Brygida Ślaska, Aleksandra Szabelak
Ectoine (ECT) is a compatible solute synthesized mostly by halophilic microorganisms subjected to various stressful factors. Its protective properties in bacteria and some populations of isolated cells subjected to different stressors are reported; however, little is known on its effects against a commonly used compound, ethanol (ETH). The purpose of our study was to determine the effects of ETH alone (at 20 and 60 g/L) and in the combination with various concentrations of ECT (5, 10, and 25 mg/L) at various times of exposure on behavioural, physiological, and biochemical parameters of a model invertebrate Daphnia magna...
June 8, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29948157/seasonal-variation-in-energy-expenditure-in-a-rodent-inhabiting-a-winter-rainfall-desert
#8
Rebecca Rimbach, Stéphane Blanc, Alexandre Zahariev, Maria Gatta, Neville Pillay, Carsten Schradin
Animals that spend more energy than they obtain risk entering allostatic overload, reducing survival and fitness. They are predicted to adjust their daily energy expenditure (DEE) during periods of food scarcity. Adjustments of DEE to changes in food availability have been well-studied in species in temperate zones during winter, but less so in species enduring seasonal droughts. Likely mechanisms regulating DEE involve adjustments of activity and maintenance metabolism. Species that experience seasonal droughts and changes in food availability, like the African striped mouse (Rhabdomys pumilio), are appropriate model organisms to study the regulation of seasonal changes of DEE...
June 8, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29804127/monitoring-responses-to-variation-in-food-supply-for-a-migratory-waterfowl-american-black-duck-anas-rubripes-in-winter
#9
Perry S Barboza, Dennis G Jorde
Wintering Black Ducks (Anas rubripes) concentrate in wetlands along the Atlantic coast where natural and anthropogenic disturbances have increased over the last 50 years, a period in which the population of Black Ducks has declined. We studied the sensitivity of Black Ducks to perturbations in food supply that often result from disturbances by storms, predators, and people. In the paper, we characterize the responses of captive Black Ducks to shifts in food quality and availability during winter and apply those measures to a comparison of wild birds...
May 26, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29797052/mammalian-urine-concentration-a-review-of-renal-medullary-architecture-and-membrane-transporters
#10
REVIEW
C Michele Nawata, Thomas L Pannabecker
Mammalian kidneys play an essential role in balancing internal water and salt concentrations. When water needs to be conserved, the renal medulla produces concentrated urine. Central to this process of urine concentration is an osmotic gradient that increases from the corticomedullary boundary to the inner medullary tip. How this gradient is generated and maintained has been the subject of study since the 1940s. While it is generally accepted that the outer medulla contributes to the gradient by means of an active process involving countercurrent multiplication, the source of the gradient in the inner medulla is unclear...
May 24, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29796734/water-bicarbonate-modulates-the-response-of-the-shore-crab-carcinus-maenas-to-ocean-acidification
#11
Bastian Maus, Christian Bock, Hans-O Pörtner
Ocean acidification causes an accumulation of CO2 in marine organisms and leads to shifts in acid-base parameters. Acid-base regulation in gill breathers involves a net increase of internal bicarbonate levels through transmembrane ion exchange with the surrounding water. Successful maintenance of body fluid pH depends on the functional capacity of ion-exchange mechanisms and associated energy budget. For a detailed understanding of the dependence of acid-base regulation on water parameters, we investigated the physiological responses of the shore crab Carcinus maenas to 4 weeks of ocean acidification [OA, P(CO2 )w  = 1800 µatm], at variable water bicarbonate levels, paralleled by changes in water pH...
May 23, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29691634/the-ctenidium-of-the-giant-clam-tridacna-squamosa-expresses-an-ammonium-transporter-1-that-displays-light-suppressed-gene-and-protein-expression-and-may-be-involved-in-ammonia-excretion
#12
Mel V Boo, Kum C Hiong, Enan J K Goh, Celine Y L Choo, Wai P Wong, Shit F Chew, Yuen K Ip
Ammonium transporters (AMTs) can participate in ammonia uptake or excretion across the plasma membrane of prokaryotic, plant and invertebrate cells. The giant clam, Tridacna squamosa, harbors nitrogen-deficient symbiotic zooxanthellae, and normally conducts light-enhanced ammonia absorption to benefit the symbionts. Nonetheless, it can excrete ammonia when there is a supply of exogenous nitrogen or exposed to continuous darkness. This study aimed to elucidate the role of AMT1 in the ctenidium of T. squamosa by cloning and characterizing the AMT1/AMT1, determining its subcellular localization, and examining changes in its transcript and protein expression levels in response to light exposure...
April 24, 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29380053/cardiovascular-adjustments-with-egg-temperature-at-90-incubation-in-embryonic-american-alligators-alligator-mississippiensis
#13
Derek Nelson, Dane A Crossley, Ruth M Elsey, Kevin B Tate
American alligators (Alligator mississippiensis) deposit eggs in a mound nest, potentially subjecting embryos to daily variations in temperature. Whilst adult crocodilian cardiovascular responses to changes in temperature have been investigated, similar studies in alligator embryos are limited. We investigated cardiovascular function of embryonic alligators during heating and cooling as well as at different temperatures. We measured arterial blood pressure (Pm ) and heart rate (fH ) in response to cooling (30-26 °C), heating (26-36 °C), followed by a reciprocal cooling event (36-26 °C) and assessed the cardiac baroreflex at 30 and 36 °C...
May 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29380052/immune-challenges-decrease-biliverdin-concentration-in-the-spleen-of-northern-bobwhite-quail-colinus-virginianus
#14
Melissa P Homsher, Michael T Astor, Justin K Hines, Michael W Butler
Most antioxidants have multiple functions; in addition to minimizing oxidative damage, many antioxidants have immune-modulating properties. For example, biliverdin is produced in the liver and spleen from the breakdown of heme, and has putative immune-suppressing and antioxidant properties. However, the majority of these properties have been investigated in vitro or in mammalian models, in which biliverdin reductase converts virtually all biliverdin to bilirubin. Thus, biliverdin's physiological roles remain largely untested...
May 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29350264/linking-muscle-metabolism-and-functional-variation-to-field-swimming-performance-in-bluegill-sunfish-lepomis-macrochirus
#15
David J Ellerby, Shauna Cyr, Angela X Han, Mika Lin, Lloyd A Trueblood
Skeletal muscle has diverse mechanical roles during locomotion. In swimming fish, power-producing muscles work in concert with the accessory muscles of the fins which augment and control power transfer to the water. Although fin muscles represent a significant proportion of the locomotor muscle mass, their physiological properties are poorly characterized. To examine the relationship between muscle metabolism and the differing mechanical demands placed on distinct muscle groups, we quantified the aerobic and glycolytic capacities of the myotomal, pectoral and caudal muscles of bluegill sunfish...
May 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29313093/baseline-glucose-level-is-an-individual-trait-that-is-negatively-associated-with-lifespan-and-increases-due-to-adverse-environmental-conditions-during-development-and-adulthood
#16
Bibiana Montoya, Michael Briga, Blanca Jimeno, Sander Moonen, Simon Verhulst
High baseline glucose levels are associated with pathologies and shorter lifespan in humans, but little is known about causes and consequences of individual variation in glucose levels in other species. We tested to what extent baseline blood glucose level is a repeatable trait in adult zebra finches, and whether glucose levels were associated with age, manipulated environmental conditions during development (rearing brood size) and adulthood (foraging cost), and lifespan. We found that: (1) repeatability of glucose levels was 30%, both within and between years...
May 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29299670/flexibility-is-the-key-metabolic-and-thermoregulatory-behaviour-in-a-small-endotherm
#17
Franz Langer, Nadine Havenstein, Joanna Fietz
Hibernation is the most effective way to reduce thermoregulatory costs during periods of unfavourable environmental conditions. In preparation to hibernation, fat-storing hibernators accumulate large quantities of body fat, which increases their locomotor costs and also the risk of predation. As a consequence, there should be a strong selective pressure to restrict pre-hibernation fattening to a short-time period before the onset of hibernation. The edible dormouse (Glis glis) is characterized by having adapted its whole life history to the irregularly occurring mast-seeding pattern of the European beech (Fagus sylvaticus)...
May 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29299669/air-breathing-behavior-oxygen-concentrations-and-ros-defense-in-the-swimbladders-of-two-erythrinid-fish-the-facultative-air-breathing-jeju-and-the-non-air-breathing-traira-during-normoxia-hypoxia-and-hyperoxia
#18
Bernd Pelster, Chris M Wood, Ellen Jung, Adalberto L Val
The jeju Hoplerythrinus unitaeniatus and the traira Hoplias malabaricus are two neighboring genera from the family of erythrinid fish, both possessing a two-chambered physostomous swimbladder. In the jeju the anterior section of the posterior bladder is highly vascularized, and the swimbladder is used for aerial respiration; the traira, in turn, is a water-breather that uses the swimbladder as a buoyancy organ and not for aerial oxygen uptake. Measurement of swimbladder oxygen partial pressure (PO2 ) of fish kept at 26 °C in normoxic, hyperoxic (28-32 mg O2 L- 1 ) or hypoxic (1-1...
May 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29290001/dropping-the-base-recovery-from-extreme-hypercarbia-in-the-co-2-tolerant-pacific-hagfish-eptatretus-stoutii
#19
Alexander M Clifford, Alyssa M Weinrauch, Greg G Goss
Hagfish are capable of tolerating extreme hypercapnia (> 30 Torr) by mounting substantial plasma [HCO3 - ] (hypercarbia) to compensate for CO2 -mediated acidosis. The goal of this study was to characterize the mechanistic hypercarbia-recovery strategies in the highly CO2 tolerant hagfish. We exposed hagfish to hypercapnia (30 Torr) for 48 h and allowed a 24 h recovery period in normocapnic seawater. Within 8 h of the recovery period, the compensatory plasma [HCO3 - ] load (~ 70 mmol L-1 ) was rapidly offloaded...
May 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
https://www.readbyqxmd.com/read/29218398/enhanced-hemoglobin-oxygen-unloading-in-migratory-salmonids
#20
Jacelyn J Shu, Till S Harter, Phillip R Morrison, Colin J Brauner
Recent findings indicate that some teleost fishes may be able to greatly enhance hemoglobin-oxygen (Hb-O2 ) unloading at the tissues under conditions that result in catecholamine release. The putative mechanism relies on the high pH sensitivity of teleost hemoglobin (Hb), intracellular red blood cell (RBC) pH regulation via β-adrenergic Na+ /H+ exchanger (β-NHE) activity, and plasma-accessible carbonic anhydrase at the tissues that short-circuits RBC pH regulation. Previous studies have shown that in rainbow trout, this system may double Hb-O2 unloading to red muscle compared to a situation without short-circuiting...
May 2018: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
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