Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

The roles of diffusion and convection in ventilation of animal burrows
AbstractThe relationship between body mass and the respiratory microenvironment of burrowing animals is examined using artificial burrows containing surrogate animals that simulate O2 consumption by removal of air and simultaneous replacement with N2. Allometric relationships between body mass and burrow radius, nest chamber radius, and O2 consumption rate show that published mathematical predictions of diffusion-mediated gas exchange are adequate to describe the respiratory environments of animals in small blind-ending burrows through porous substrata. Diffusion is sufficient to ventilate burrows containing small mammals ...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - August 13, 2021 Category: Physiology Source Type: research

Seasonal changes in steroid and thyroid hormone content in shed skins of the tegu lizard Salvator merianae
AbstractSampling blood for endocrine analysis from some species may not be practical or ethical. Quantification of hormones extracted from nontypical sample types, such as keratinized tissues, offers a less invasive alternative to the traditional collection and analysis of blood. Here, we aimed to validate assays by using parallelism and accuracy tests for quantification of testosterone, corticosterone, progesterone, and triiodothyronine (T3) in shed skins of tegu lizards. We assessed whether hormone content of sheds varied across one year similar to what was previously detected in plasma samples. In addition, we aimed to ...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - August 11, 2021 Category: Physiology Source Type: research

Adaptation of AMPK-mTOR-signal pathways and lipid metabolism in response to low- and high-level rapeseed meal diet in Chinese perch (Siniperca chuatsi)
AbstractIt is well known that carnivorous fish cannot use plant-proteins efficiently. They affect lipid metabolism of fish and cause serious problems to fish health. The reasons for this deficiency of fish metabolism are not known well. Chinese perch, a carnivorous fish, can accept artificial diet after domestication and is also considered as a novel model of fish for nutrition studies. Therefore, the aim of this study was to explore the effect of fish meal replacement by low- or high-rapeseed meal on lipid and glucose metabolism of Chinese perch. Three experimental diets were formulated with 0, 10%, and 30% rapeseed meal,...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - August 9, 2021 Category: Physiology Source Type: research

Baroreflex responses to activity at different temperatures in the South American rattlesnake, Crotalus durissus
AbstractIn humans, physical exercise imposes narrower limits for the heart rate (fH) response of the baroreflex, and vascular modulation becomes largely responsible for arterial pressure regulation. In undisturbed reptiles, the baroreflex-relatedfH alterations at the operating point (Gop) decreases at elevated body temperatures (Tb) and the vascular regulation changes accordingly. We investigated how the baroreflex of rattlesnakes,Crotalus durissus, is regulated during an activity at differentTb, expecting that activity would reduce the capacity of the cardiac baroreflex neural pathway to buffer arterial pressure fluctuati...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - August 7, 2021 Category: Physiology Source Type: research

Effects of temperature on the locomotor performance and contraction properties of skeletal muscle from two Phrynocephalus lizards at high and low altitude
In this study, which compares P. erythrurus with  the lowlandPhrynocephalus przewalskii, we evaluated the locomotor performance at different body temperatures, the effects of temperature and oxygen partial pressure (PO2) on the contractile properties of iliofibularis (IF) muscle in vitro, ATPase activity of IF muscle at different temperatures, and the fiber types of IF muscle. LowlandP. przewalskii runs significantly faster than highlandP. erythrurus at all test body temperatures. Almost all contractile properties of the IF muscle ofP. przewalskii were better than that ofP. erythrurus under all test temperatures and PO2....
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - August 3, 2021 Category: Physiology Source Type: research

Moving average and standard deviation thresholding (MAST): a novel algorithm for accurate R-wave detection in the murine electrocardiogram
We present herein moving average and standard deviation thresholding (MAST), a novel, open-access algorithm developed to perform automated, accurate, and noise-robust single-channel R-wave detection from ECG obtained in chronically instrumented mice. MAST additionally and automatically excludes and annotates segments where R-wave detection is not possible due to artefact levels exceeding signal levels. Customizable settings (e.g. window width of moving average) allow for MAST to be scaled for use in non-murine species. Two expert reviewers compared MAST ’s performance (true/false positive and false negative detections) w...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - July 25, 2021 Category: Physiology Source Type: research

Magnesium transport in the aglomerular kidney of the Gulf toadfish (Opsanus beta)
AbstractDespite having an aglomerular kidney, Gulf toadfish can survive in water ranging from nearly fresh up to 70 parts per thousand salinity. In hyperosmotic environments, the major renal function is to balance the passive Mg2+ load from the environment with an equal excretion. However, the molecular transporters involved in Mg2+ secretion are poorly understood. We investigated whether environmental MgCl2 alone or in combination with elevated salinity affected transcriptional regulation of genes classically involved in renal Mg2+ secretion (slc41a1, slc41a3, cnnm3) together with three novel genes (trpm6, trpm7,claudin-1...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - July 23, 2021 Category: Physiology Source Type: research

α1-Adrenergic receptor regulates papillary muscle and aortic segment contractile function via modulation of store-operated Ca2+ entry in long-tailed ground squirrels Urocitellus undulatus
AbstractThe effect of phenylephrine (PE) on right ventricle papillary muscle (PM) and aortic segment (AS) contractile activity was studied in long-tailed ground squirrelsUrocitellus undulatus during summer activity, torpor and interbout active (IBA) periods in comparison to rat. We found that PE (10  μM) exerts positive inotropic effect on ground squirrel PM that was blocked by α1-AR inhibitor—prazosin. PE differently affected frequency dependence of PM contraction in ground squirrels and rats. PE significantly increased the force of PM contraction in summer and hibernating ground squirrel s including both torpor and ...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - July 23, 2021 Category: Physiology Source Type: research

Aerobic and anaerobic movement energetics of hybrid and pure parental abalone
AbstractThe underlying mechanisms controlling growth heterosis in marine invertebrates remain poorly understood. We used pure blacklip (Haliotis rubra) and greenlip (Haliotis laevigata) abalone, as well as their hybrid, to test whether differences in movement and/or aerobicversus anaerobic energy use are linked to a purported increased growth rate in hybrids. Abalone were acclimated to control (16  °C) and typical summer temperatures (23 °C), each with oxygen treatments of 100% air saturation (O2sat) or 70% O2sat. The experiment then consisted of two phases. During the first phase (chronic exposure), movement and oxyge...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - July 18, 2021 Category: Physiology Source Type: research

Cortisol and glucocorticoid receptor 2 regulate acid secretion in medaka (Oryzias latipes) larvae
AbstractFreshwater fish live in environments where pH levels fluctuate more than those in seawater. During acidic stress, the acid –base balance in these fish is regulated by ionocytes in the gills, which directly contact water and function as an external kidney. In ionocytes, apical acid secretion is largely mediated by H+-ATPase and the sodium/hydrogen exchanger (NHE). Control of this system was previously proposed to depend on the hormone, cortisol, mostly based on studies of zebrafish, a stenohaline fish, which utilize H+-ATPase as the main route for apical acid secretion. However, the role of cortisol is poorly unde...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - July 17, 2021 Category: Physiology Source Type: research

In vivo cardiopulmonary impact of skeletal M3Dq DREADD expression: a pilot study
AbstractThe muscarinic M3 receptor (M3R) is implicated in cardiopulmonary control and many other peripheral physiologic functions. Previous observations report mortality in mice expressing a Gq-linked designer G-protein coupled receptor (Dq) selectively in striated muscle, while M3Dq DREADD (Designer Receptor Exclusively Activated by Designer Drug), selectively expressed in skeletal muscle (SKM) impacts glucose metabolism. We investigated whether activation of SKM M3Dq impacts cardiopulmonary function. Heart rate (HR), body temperature (Tb) and locomotor activity (ACT) were measured in 4 conscious, chronically instrumented...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - July 16, 2021 Category: Physiology Source Type: research

Use beer to calibrate your CO2 analyser: celebrate!
AbstractBottled beer is used to calibrate a CO2 analyser by measuring the dilution of O2 when gas collected in the headspace of the bottle is diluted with atmospheric air. The method is simple and provides an accurate calibration of a CO2 analyser in the field without the need or hassle of transporting expensive calibration gas. (Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology)
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - July 15, 2021 Category: Physiology Source Type: research

Editorial Expression of Concern to: Hypoxia attenuate ionic transport in the isolated gill epithelium of Carcinus maenas
(Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology)
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - July 14, 2021 Category: Physiology Source Type: research

Nutritional influences on enzyme activities in saliva of Asian and African elephants
This study aimed to determine the influence of feeding on enzyme activities in saliva of both elephant species to differentiate from species-specific effects. Additionally, season and housing conditions on salivary enzyme activities in non-fed elephants of both species were investigated. Salivary amylase (sAA), lysozyme (sLYS) and peroxidase (sPOD) activity were measured photometrically or fluorometrically. Results of this study reinforce previous observations of higher basic sAA activity in Asian elephants compared to African elephants. Salivary LYS and sPOD activity showed neither species-specific nor housing-specific di...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - July 7, 2021 Category: Physiology Source Type: research

Metabolic scaling: individual versus intraspecific scaling of Nile tilapia (Oreochromis niloticus)
We examined intraspecific scaling of the resting metabolic rate (RMR) of Nile tilapia (Oreochromis niloticus) under different culture conditions and further explored the allometric relationships between organ mass (heart, liver, brain, gills, viscera, and red muscles) and blood parameters (erythrocyte size and red blood cell counts) and body mass.Oreochromis niloticus were bred in individual and group cultures. The scaling exponent of the RMR in the individual cultures wasb = 0.620–0.821 (n = 30) and that in the group culture wasb = 0.770 [natural logarithm (ln) RMR = 0.770 lnM− 1.107 (n = 76)]. T...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - June 30, 2021 Category: Physiology Source Type: research