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.

Avoiding the effects of translocation on the estimates of the metabolic rates across an elevational gradient
In this study, we measured resting metabolic rate (RMR) of three populations of the Mesquite lizard (Sceloporus grammicus, Wiegmann 1828) at their native elevations (i.e., 2600, 3200 and 4100  m). Our results showed that at native elevations, mass specific RMR of lizards from the high elevation population (4100 m) did not differ from the RMR of the other populations (i.e., 2600 and 3200 m), whereas the lizards from the low elevation (2600 m) had lower RMR than those from the intermed iate population. These results differ from a previous study in which the RMR of lizards from the same populations were reported to increa...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - July 18, 2022 Category: Physiology Source Type: research

Osmorespiratory compromise in an elasmobranch: oxygen consumption, ventilation and nitrogen metabolism during recovery from exhaustive exercise in dogfish sharks (Squalus suckleyi)
AbstractThe functional trade-off between respiratory gas exchange versus osmolyte and water balance that occurs at the thin, highly vascularized gills of fishes has been termed the osmorespiratory compromise. Increases in gas exchange capacity for meeting elevated oxygen demands can end up favoring the passive movement of osmolytes and water, potentially causing a disturbance in osmotic balance. This phenomenon has been studied only sparsely in marine elasmobranchs. Our goal was to evaluate the effects of exhaustive exercise (as a modulator of oxygen demand) on oxygen consumption (MO2), branchial losses of nitrogenous prod...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - July 15, 2022 Category: Physiology Source Type: research

Microvascular anatomy suggests varying aerobic activity levels in the adipose tissues of diving tetrapods
AbstractAdipose tissue has many important functions including metabolic energy storage, endocrine functions, thermoregulation and structural support. Given these varied functions, the microvascular characteristics within the tissue will have important roles in determining rates/limits of exchange of nutrients, waste, gases and molecular signaling molecules between adipose tissue and blood. Studies on skeletal muscle have suggested that tissues with higher aerobic capacity contain higher microvascular density (MVD) with lower diffusion distances (DD) than less aerobically active tissues. However, little is known about MVD i...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - July 2, 2022 Category: Physiology Source Type: research

MicroRNA biogenesis proteins follow tissue-dependent expression during freezing in Dryophytes versicolor
AbstractGrey tree frogs (Dryophytes versicolor) have the remarkable ability to endure full-body freezing over the winter, with up to 42% of total body water converted into extracellular ice. Survival is aided by metabolic rate depression that greatly reduces tissue energy costs over the winter. Post-transcriptional controls on gene expression which include miRNA regulation of gene transcripts can aid implementation of the reversible changes required for freeze tolerance, since miRNAs are ideal for facilitating the rapid metabolic reorganization needed for this process. The energy cost for synthesizing new miRNAs is low, an...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - June 24, 2022 Category: Physiology Source Type: research

A thermodynamic-based approach to model the entry into metabolic depression by mammals and birds
AbstractFor decades, there was an intense debate in relation to the mechanism behind the entry into metabolic depression (EMD) of mammals and birds. The fulcrum of the argument was whether the depression of metabolic rate (\(\dot{W}\)) was caused by the drop in body temperature, the so-called “Q10 effect ”, or whether it was caused by a metabolic downregulation. One present-day model of this process is a qualitative (textual) description: the initial step of EDM would be a downregulation in\(\dot{W}\) from the value maintaining euthermia at a given ambient temperature to the basal metabolic rate of the animal and, then...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - June 23, 2022 Category: Physiology Source Type: research

Na+/HCO3 − cotransporter 1 (nbce1) isoform gene expression during smoltification and seawater acclimation of Atlantic salmon
AbstractThe life history of Atlantic salmon (Salmo salar) includes an initial freshwater phase (parr) that precedes a springtime migration to marine environments as smolts. The development of osmoregulatory systems that will ultimately support the survival of juveniles upon entry into marine habitats is a key aspect of smoltification. While the acquisition of seawater tolerance in all euryhaline species demands the concerted activity of specific ion pumps, transporters, and channels, the contributions of Na+/HCO3− cotransporter 1 (Nbce1) to salinity acclimation remain unresolved. Here, we investigated the branchial and i...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - June 17, 2022 Category: Physiology Source Type: research

Correction to: Prejuveniles of Mugil liza (Actinopterygii; Fam. Mugilidae) show digestive and metabolic flexibility upon different postprandial times and refeeding
(Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology)
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - June 10, 2022 Category: Physiology Source Type: research

Relationship between gene expression networks and muscle contractile physiology differences in Anolis lizards
AbstractMuscles facilitate most animal behavior, from eating to fleeing. However, to generate the variation in behavior necessary for survival, different muscles must perform differently; for instance, sprinting requires multiple rapid muscle contractions, whereas biting may require fewer contractions but greater force. Here, we use a transcriptomic approach to identify genes associated with variation in muscle contractile physiology among different muscles from the same individual. We measured differential gene expression between a leg and jaw muscle ofAnolis lizards known to differ in muscle contractile physiology and pe...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - May 20, 2022 Category: Physiology Source Type: research

The evolution of human fatigue resistance
AbstractHumans differ from African great apes in numerous respects, but the chief initial difference setting hominins on their unique evolutionary trajectory was habitual bipedalism. The two most widely supported selective forces for this adaptation are increased efficiency of locomotion and improved ability to feed in upright contexts. By 4 million years ago, hominins had evolved the ability to walk long distances but extreme selection for endurance capabilities likely occurred later in the genusHomo to help them forage, power scavenge and persistence hunt in hot, arid conditions. In this review we explore the hypothesis ...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - May 12, 2022 Category: Physiology Source Type: research