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.

Noradrenergic tone is not required for neuronal activity-induced rebound sleep in zebrafish
AbstractSleep pressure builds during wakefulness, but the mechanisms underlying this homeostatic process are poorly understood. One zebrafish model suggests that sleep pressure increases as a function of global neuronal activity, such as during sleep deprivation or acute exposure to drugs that induce widespread brain activation. Given that the arousal-promoting noradrenergic system is important for maintaining heightened neuronal activity during wakefulness, we hypothesised that genetic and pharmacological reduction of noradrenergic tone during drug-induced neuronal activation would dampen subsequent rebound sleep in zebra...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - July 22, 2023 Category: Physiology Source Type: research

Evaluation of haemolymph phenoloxidase activity from the grub of Zophobas morio as a predictor of immune response
AbstractIn insects, enzyme phenoloxidase plays a critical role in cuticular sclerotisation and defensive functions. In the present investigation, haemolymph phenoloxidase activity from the grub ofZophobas morio was attempted to evaluate as a reliable predictor of insect ’s immunological response. Among the various substrates tested, L-DOPA was chosen as an appropriate substrate due to its high oxidation. The optimum pH and temperature for haemolymph PO activity was found to be 8 and 30 °C, respectively. The optimum substrate concentration of L-DOPA was found to be 7.5 mM for subsequent PO enzymatic characterisation. A...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - July 17, 2023 Category: Physiology Source Type: research

Born in the cold: contrasted thermal exchanges and maintenance costs in juvenile and adult snow buntings on their breeding and wintering grounds
AbstractSeveral species of passerines leave their nest with unfinished feather growth, resulting in lower feather insulation and increased thermoregulatory demands compared to adults. However, feather insulation is essential for avian species breeding at northern latitudes, where cold conditions or even snowstorms can occur during the breeding season. In altricial arctic species, increased heat loss caused by poor feather insulation during growth could be counter-adaptative as it creates additional energy demands for thermoregulation. Using flow-through respirometry, we compared resting metabolic rate at thermoneutrality (...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - June 29, 2023 Category: Physiology Source Type: research

Chronic hypoxia and hyperoxia alter tissue-specific fatty acid profile and FD6D and elongase gene expression levels in rainbow trout (Oncorhynchus mykiss)
AbstractCommercially important trout species, especially rainbow trout, are under great threat due to several negative factors affecting oxygen levels in water such as global warming and eutrophication. In our study, rainbow trout (Oncorhynchus mykiss) was exposed to chronic (for 28  days) hypoxia (4.0 ± 0.5 mg/L) and hyperoxia (12 ± 1.2 mg/L) in order to evaluate the alteration of fatty acid profiles in muscle, liver and gill tissues. In addition, delta-6-desaturase and elongase gene expression profiles were measured in liver, kidney and gill tissues. The amount o f saturated fatty acids increased by oxygen a...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - June 7, 2023 Category: Physiology Source Type: research

Developmental, physiologic and phylogenetic perspectives on the expression and regulation of myosin heavy chains in mammalian skeletal muscles
AbstractThe kinetics of myosin controls the speed and power of muscle contraction. Mammalian skeletal muscles express twelve kinetically different myosin heavy chain (MyHC) genes which provides a wide range of muscle speeds to meet different functional demands. Myogenic progenitors from diverse craniofacial and somitic mesoderm specify muscle allotypes with different repertoires for MyHC expression. This review provides a brief synopsis on the historical and current views on how cell lineage, neural impulse patterns, and thyroid hormone influence MyHC gene expression in muscles of the limb allotype during development and i...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - June 5, 2023 Category: Physiology Source Type: research

Biochemical response of two earthworm taxa exposed to freezing
In this study, we used1H NMR to investigate metabolomic changes in two freeze-tolerant earthworm taxa,Dendrobaena octaedra and one of the genetic lineages ofEisenia sp. aff.nordenskioldi f.pallida. A total of 45 metabolites were quantified. High concentrations of glucose were present in frozen tissues of both taxa. No other putative cryoprotectants were found. We detected high levels of glycolysis end products and succinate in frozen animals, indicating the activation of glycolysis. Concentrations of many other substances also significantly increased. On the whole, metabolic change in response to freezing was much more pro...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - June 2, 2023 Category: Physiology Source Type: research

Lactating SKH-1 furless mice prioritize own comfort over growth of their pups
AbstractLactation is the most energetically demanding physiological process that occurs in mammalian females, and as a consequence of this energy expenditure, lactating females produce an enormous amount of excess heat. This heat is thought to limit the amount of milk a mother produces, and by improving heat dissipation, females may improve their milk production and offspring quality. Here we used SKH-1 hairless mice as a natural model of improved heat dissipation. Lactating mothers were given access to a secondary cage to rest away from their pups, and this secondary cage was kept either at room temperature (22  °C) in ...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - May 27, 2023 Category: Physiology Source Type: research

Steroid hormone-dependent changes in trehalose physiology in the silkworm, Bombyx mori
AbstractHolometabolous insects undergo metamorphosis to reconstruct their body to the adult form during pupal period. Since pupae cannot take any diets from the outside because of a hard pupal cuticle, those insects stock up on nutrients sufficient for successful metamorphosis during larval feeding period. Among those nutrients, carbohydrates are stored as glycogen or trehalose, which is the major blood sugar in insects. The hemolymph trehalose is constantly high during the feeding period but suddenly decreases at the beginning of the prepupal period. It is believed that trehalase, which is a trehalose-hydrolyzing enzyme, ...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - May 23, 2023 Category: Physiology Source Type: research

Correction to: Mitochondrial volume density and evidence for its role in adaptive divergence in response to thermal tolerance in threespine stickleback
(Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology)
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - May 15, 2023 Category: Physiology Source Type: research

Energy and time optimization during exit from torpor in vertebrate endotherms
AbstractTorpor is used in small sized birds and mammals as an energy conservation trait. Considerable effort has been put towards elucidating the mechanisms underlying its entry and maintenance, but little attention has been paid regarding the exit. Firstly, we demonstrate that the arousal phase has a stereotyped dynamic: there is a sharp increase in metabolic rate followed by an increase in body temperature and, then, a damped oscillation in body temperature and metabolism. Moreover, the metabolic peak is around two-fold greater than the corresponding euthermic resting metabolic rate. We then hypothesized that either time...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - May 12, 2023 Category: Physiology Source Type: research