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.

Oxygen consumption and acid secretion in isolated gas gland cells of the European eel Anguilla anguilla
AbstractSwimbladder gas gland cells are known to produce lactic acid required for the acidification of swimbladder blood and decreasing the oxygen carrying capacity of swimbladder blood, i.e., the onset of the Root effect. Gas gland cells have also been shown to metabolize glucose via the pentose phosphate shunt, but the role of the pentose phosphate shunt for acid secretion has not yet been evaluated. Similarly, aerobic metabolism of gas gland cells has been largely neglected so far. In the present study, we therefore simultaneously assessed the role of glycolysis and of the pentose phosphate shunt for acid secretion and ...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - March 14, 2022 Category: Physiology Source Type: research

Changing lanes: seasonal differences in cellular metabolism of adipocytes in grizzly bears (Ursus arctos horribilis)
AbstractObesity is among the most prevalent of health conditions in humans leading to a multitude of metabolic pathologies such as type 2 diabetes and hyperglycemia. However, there are many wild animals that have large seasonal cycles of fat accumulation and loss that do not result in the health consequences observed in obese humans. One example is the grizzly bear (Ursus arctos horribilis) that can have body fat content  >  40% that is then used as the energy source for hibernation. Previous in vitro studies found that hibernation season adipocytes exhibit insulin resistance and increased lipolysis. Yet, other aspe...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - March 1, 2022 Category: Physiology Source Type: research

Phenotypic plasticity to chronic cold exposure in two species of Peromyscus from different environments
AbstractEffective thermoregulation is important for mammals, particularly those that remain winter-active. Adjustments in thermoregulatory capacity in response to chronic cold can improve capacities for metabolic heat production (cold-induced maximal oxygen consumption,\({\dot{\text{V}}\text{O}}_{{2}} {\text{max}}\)), minimize rates of heat loss (thermal conductance), or both. This can be challenging for animals living in chronically colder habitats where necessary resources (i.e., food, O2) for metabolic heat production are limited. Here we used lowland native white-footed mice (Peromyscus leucopus) and highland deer mice...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - March 1, 2022 Category: Physiology Source Type: research

Seasonal variations in the intermediate metabolism in South American tree-frog Boana pulchella
This study evaluated the main energy substrate levels and metabolism ofB. pulchella in plasma, liver and muscle of male individuals collected in winter, spring, summer and fall in the state of Rio Grande do Sul, Brazil. Our results showed thatB. pulchella has a higher glycolytic oxidation rate in liver (P = 0.0152) and muscle (P = 0.0003) and higher glycogenesis from glucose in muscle (P = 0.0002) in summer, indicating the main energy substrates in this season is glucose. The higher muscle glycogen (P = 0.0008) and lower plasma glucose in fall (P = 0.0134) may indicate an anticipatory regulation for st...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - March 1, 2022 Category: Physiology Source Type: research

Leaf-cutting ants ’ critical and voluntary thermal limits show complex responses to size, heating rates, hydration level, and humidity
AbstractThermal variation has complex effects on organisms and they respond to these effects through combined behavioral and physiological mechanisms. However, it is less clear how these traits combine in response to changes in body condition (e.g., size, hydration) and environmental factors that surround the heating process (e.g., relative humidity, start temperatures, heating rates). We tested whether these body conditions and environmental factors influence sequentially measured Voluntary Thermal Maxima (VTmax) and Critical Thermal Maxima, (CTmax) in leaf-cutting ants (Atta sexdens rubropilosa, Forel, 1908). VTmax and C...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - March 1, 2022 Category: Physiology Source Type: research

Habitat aridity as a determinant of the trade-off between water conservation and evaporative heat loss in bats
AbstractThe maintenance of water balance in arid environments might represent a formidable challenge for Chiroptera, since they have high surface-to-volume ratios. In deserts, bats conserve water, for example, using daily torpor, but they also might experience episodic heat bouts, when they may need to increase total evaporative water loss (TEWL) to thermoregulate. We hypothesized that in bats, habitat aridity and its variability determine a trade-off between water conservation and thermoregulation via evaporative means. To test this hypothesis, we collated data from the literature of 22 species of bats on TEWL, body tempe...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - March 1, 2022 Category: Physiology Source Type: research

Changes in CO2 sensitivity during entrance into, and arousal from hibernation in Ictidomys tridecemlineatus
We examined the time course of the changes in ventilation, O2 consumption rates (\({\dot{\text{V}}}\)o2), CO2 excretion rates, body temperature, and hence the RER and ACR (air convection ratio, ventilation/\({\dot{\text{V}}}\)o2) and the HCVR throughout entrance and arousal into and out of hibernation in 13-lined ground squirrels to confirm this. We observed a significant drop (entrance) and rise (arousal) in the RER produced by hypo- and hyperventilation, respectively. CO2 chemo-sensitivity while the RER was reduced on entrance was blunted and rose late in entrance. On arousal, CO2 chemo-sensitivity was elevated when the ...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - March 1, 2022 Category: Physiology Source Type: research

Morphometrics and blood analytes of leatherback sea turtle hatchlings (Dermochelys coriacea) from Florida: reference intervals, temporal trends with clutch deposition date, and body size correlations
AbstractThe northwest Atlantic leatherback sea turtle (Dermochelys coriacea) population is exhibiting decreasing trends along numerous nesting beaches. Since population health and viability are inherently linked, it is important to establish species- and life-stage class-specific blood analyte reference intervals (RIs) so that effects of future disturbances on organismal health can be better understood. For hatchling leatherbacks, the objectives of this study were to (1) establish RIs for morphometrics and blood analytes; (2) evaluate correlations between hatchling morphometrics, blood analytes, and hatching success; and (...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - March 1, 2022 Category: Physiology Source Type: research

A review of the effects of incubation conditions on hatchling phenotypes in non-squamate reptiles
AbstractDeveloping embryos of oviparous reptiles show substantial plasticity in their responses to environmental conditions during incubation, which can include altered sex ratios, morphology, locomotor performance and hatching success. While recent research and reviews have focused on temperature during incubation, emerging evidence suggests other environmental variables are also important in determining hatchling phenotypes. Understanding how the external environment influences development is important for species management and requires identifying how environmental variables exert their effects individually, and how th...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - March 1, 2022 Category: Physiology Source Type: research

Structure and permeability of the egg capsule of the placental Australian sharpnose shark, Rhizoprionodon taylori
AbstractShark placentae are derived from modifications to the fetal yolk sac and the maternal uterine mucosa. In almost all placental sharks, embryonic development occurs in an egg capsule that remains intact for the entire pregnancy, separating the fetal tissues from the maternal tissues at the placental interface. Here, we investigate the structure and permeability of the egg capsules that surround developing embryos of the placental Australian sharpnose shark (Rhizoprionodon taylori) during late pregnancy. The egg capsule is an acellular fibrous structure that is 0.42  ± 0.04 μm thick at the placental interface b...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - March 1, 2022 Category: Physiology Source Type: research

De novo transcriptome assembly of the midgut glands of herbivorous land crabs, Chiromantes haematocheir, and identification of laccase genes involved in lignin degradation
In this study, we performed RNA-seq analysis to detect biomass-degrading enzymes. A de novo transcriptome assembly in the midgut glands of molting and non-moltingC. haematocheir crabs was constructed using RNA sequencing. Illumina sequencing generated 44,937,002 and 44,394,310 reads from the two midgut glands. In total, 178,710 contigs with an average length of 750  bp and an N50 value of 1,235 bp were assembled, of which 37,890 contigs were annotated using BLASTx search against the NCBI database. We identified 22 contigs (11 genes) belonging to the laccase family and 44 contigs (22 genes) belonging to the peroxidase fam...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - March 1, 2022 Category: Physiology Source Type: research

Mitochondrial respiration in rats during hypothermia resulting from central drug administration
AbstractThe ability to induce a hypothermia resembling that of natural torpor would be greatly beneficial in medical and non-medical fields. At present, two procedures based on central nervous pharmacological manipulation have been shown to be effective in bringing core body temperature well below 30  °C in the rat, a non-hibernator: the first, based on the inhibition of a key relay in the central thermoregulatory pathway, the other, based on the activation of central adenosine A1 receptors. Although the role of mitochondria in the activation and maintenance of torpor has been extensively stud ied, no data are available ...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - March 1, 2022 Category: Physiology Source Type: research

Fatty acid profiles of feeding and fasting bears: estimating calibration coefficients, the timeframe of diet estimates, and selective mobilization during hibernation
AbstractAccurate information on diet composition is central to understanding and conserving carnivore populations. Quantitative fatty acid signature analysis (QFASA) has emerged as a powerful tool for estimating the diets of predators, but ambiguities remain about the timeframe of QFASA estimates and the need to account for species-specific patterns of metabolism. We conducted a series of feeding experiments with four juvenile male brown bears (Ursus arctos) to (1) track the timing of changes in adipose tissue composition and QFASA diet estimates in response to a change in diet and (2) quantify the relationship between con...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - March 1, 2022 Category: Physiology Source Type: research

Comparative transcriptomics reveal tissue level specialization towards diet in prickleback fishes
AbstractBeyond a few obvious examples (e.g., gut length, amylase activity), digestive and metabolic specializations towards diet remain elusive in fishes. Thus, we compared gut length, δ13C and δ15N signatures of the liver, and expressed genes in the intestine and liver of wild-caught individuals of four closely-related, sympatric prickleback species (family Stichaeidae) with different diets:Xiphister mucosus (herbivore), its sister taxonX. atropurpureus (omnivore),Phytichthys chirus (omnivore) and the carnivorousAnoplarchus purpurescens. We also measured the same parameters after feeding them carnivore or omnivore diets...
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - March 1, 2022 Category: Physiology Source Type: research