Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology

The present study was conducted to evaluate the effects of fasting on responses of oxidative biomarkers and antioxidant defenses using different organs and tissues of Colossoma macropomum. The fish were divided into two groups: fed (control) and fasting (7 days). After 7 days, the fish were sampled for assessment of oxidative stress biomarkers (MDA-lipid peroxidation and PCO-protein carbonyl) and antioxidant defenses (SOD-superoxide dismutase; CAT-catalase; GPX-glutathione peroxidase; and GST-glutathione-S -transferase) in the liver, intestine, gills, muscle, brain, and plasma...

Birds have the highest blood glucose among vertebrates. Several mechanisms may explain this including the lack of a functional insulin-responsive glucose transport protein, high glucagon concentrations, and reliance on lipid oxidation resulting in the production of gluconeogenic precursors. The hypothesis was that interruption of gluconeogenesis using the diabetes medication metformin would lower glucose concentrations in wild-caught birds. We captured two cohorts of adult mourning doves, Zenaida macroura, and acclimated them to captivity for two weeks...

Eriocheir sinensis megalopa has a special life history of migrating from seawater to freshwater. In order to investigate how the megalopa adapt themselves to the freshwater environment, we designed an experiment to reduce the salinity of water from 30 ppt to 0 at rates of 30 ppt, 15 ppt, 10 ppt, and 5 ppt per 24 h to evaluate the effects of different degrees of hyposaline stress on the osmotic regulation ability and antioxidant system of the megalopa. Experimental results related to osmotic pressure regulation show that the gill tissue of megalopa in the treatment group of 30 ppt/24 h rapid reduction of salinity was damaged, while in the treatment group of 5 ppt/24 h it was intact...

Eggs of oviparous reptiles are ideal models for studying evolutionary patterns of embryonic metabolism since they allow tracking of energy allocation during development. Analyzing oxygen consumption of whole eggs throughout development indicates three patterns among reptiles. Embryos initially grow and consume oxygen exponentially, but oxygen consumption slows, or drops before hatching in some species. Turtles, crocodilians, and most lizards follow curves with initial exponential increases followed by declines, whereas embryonic snakes that have been studied exhibit a consistently exponential pattern...

Superoxide dismutases (SODs) are antioxidant enzymes that protect cells from oxidation. Three SODs have been identified in mammals, but there is limited information in teleosts. This study investigates SODs in the European eel and their expression patterns during testis maturation. Phylogenetic and synteny analyses revealed SODs paralogs and their evolution in vertebrates. The eel possesses one SOD1 and two SOD2/3 (a and b), indicating SOD2 and SOD3 duplication in elopomorphs. SODs expression were then evaluated in various male and female tissues...

Fish gills are complex organs that have direct contact with the environment performing numerous functions, including gas exchange and ion regulation. Determining if gill morphometry can change under different environmental conditions to maintain and/or improve gas exchange and ion regulation is important for understanding if gill plasticity can improve survival with increasing environmental change. We assessed gill morphology (gas exchange and ion regulation metrics), hematocrit and gill Na+ /K+ ATPase activity of wild-captured blackside darter (Percina maculata), greenside darter (Etheostoma blennioides), and johnny darter (Etheostoma nigrum) at two temperatures (10 and 25 °C) and turbidity levels (8 and 94 NTU)...

We analyse the developmental and circadian profiles of expression of the genes responsible for ecdysteroidogenesis (Halloween genes) in the PGs of Rhodnius prolixus throughout larval-adult development. Extensive use of in vitro techniques enabled multiple different parameters to be measured in individual PGs. Expression of disembodied and spook closely paralleled the ecdysteroid synthesis of the same PGs, and the ecdysteroid titre in vivo, but with functionally significant exceptions. Various tissues other than PGs expressed one, both or neither genes...

Seasonal reproduction is a widely used breeding strategy in wildlife, especially vertebrates inhabiting temperate regions. Generally, ambient temperature is considered a significant factor influencing the reproductive status of animals. In the present study, wild ground squirrels (Spermophilus dauricus), typical seasonal breeders, were used as an animal model to investigate the mechanism behind the impact of low ambient temperature on testicular function. To simulate the winter environment of wild ground squirrels, we lowered the temperature gradient in the rearing environment to 4 °C...

Climate change increasingly influences the loss of biodiversity, especially in ectothermic organisms, which depend on environmental temperatures to obtain heat and regulate their life cycle. Studies that aim to understand the impact of temperature variation are important to better understand the possible impacts generated on the homeostasis of ectothermic organisms. Our objective was to characterize the responses of juvenile Liolaemus arambarensis lizards to abrupt changes in temperature, quantifying markers of body condition, intermediary and hormonal metabolism and oxidative balance...

Clogmia albipunctata (Williston, 1893) is a non-hematophagous insect belonging to the order Diptera, suborder Nematocera (Lower Diptera) and family Psychodidae. In the present work, we investigated how C. albipunctata control their midgut pH under different physiological conditions, comparing their midgut physiology with some nematoceran hematophagous species. The C. albipunctata midgut pH was measured after ingestion of sugar, protein and under the effect of the alkalinizing hormone released in the hemolymph of the hematophagous sand fly Lutzomyia longipalpis obtained just after a blood meal...

Assessments of arterial and venous blood gases are required to understand the function of respiratory organs in animals at different stages of development. We measured blood gases in the arteries entering and veins leaving the chorioallantoic membrane (CAM) in embryonic alligators (Alligator mississippiensis). The CAM accounts for virtually all gas exchange in these animals, and we hypothesized that the CAM vasculature would be larger in eggs incubated in hypoxia (10% O2 for 50% or 70% of incubation), which would be reflected in a lower partial pressure of CO2 (PCO2 )...

The baroreflex involves cardiovascular homeostatic mechanisms that buffer the system against acute deviations in arterial blood pressure. It is comprised of the cardiac limb which involves adjustments in heart rate and the peripheral limb which involves adjustments in vascular resistance. This negative feedback loop mechanism has been investigated in numerous species of adult vertebrates, however our understanding of the maturation and functional importance of the reflex in developing animals remains poorly understood...

Emerging findings point to a role for C1q/TNF-related protein 4 (CTRP4) in feeding in mammals. However, it remains unknown whether CTRP4 regulates feeding in fish. This study aimed to determine the feeding regulation function of CTRP4 in Siberian sturgeon (Acipenser baerii). In this study, the Siberian sturgeon ctrp4 (Abctrp4) gene was cloned, and Abctrp4 mRNA was shown to be highly expressed in the hypothalamus. In the hypothalamus, Abctrp4 mRNA decreased during fasting and reversed after refeeding. Subsequently, we obtained the AbCTRP4 recombinant protein by prokaryotic expression and optimized the expression and purification conditions...

Zymosan is a fungi-derived pathogen-associated molecular pattern. It activates the immune system and induces the reduction of feed passage rate in the gastrointestinal tract of vertebrates including birds. However, the mechanism mediating the zymosan-induced inhibition of feed passage in the gastrointestinal tract remains unknown. Since the medulla oblongata regulates the digestive function, it is plausible that the medulla oblongata is involved in the zymosan-induced inhibition of feed passage. The present study was performed to identify the genes that were affected by zymosan within the medulla oblongata of chicks (Gallus gallus) using an RNA sequencing approach...

BACKGROUND: The crocodilian heart is unique among reptiles with its four-chambered structure and complete intracardiac separation of pulmonary and systemic blood flows and pressures. Crocodiles have retained two aortic arches; one from each ventricle, that communicate via Foramen of Panizza, immediately distally from the aortic valves. Moreover, crocodiles can regulate vascular resistance in the pulmonary portion of the right ventricular outflow tract (RVOT). These unique features allow for a complex regulation of shunting between the pulmonary and systemic circulations...

Crustacean hyperglycemic hormone (CHH) superfamily peptides constitute a group of neurohormones, including the crustacean hyperglycemic hormone (CHH), molt-inhibiting hormone (MIH), and gonad-inhibiting hormone (GIH) or vitellogenesis-inhibiting hormone (VIH), which reportedly play an essential role in regulating various biological activities by binding to their receptors in crustaceans. Although bioinformatics analyses have identified G protein-coupled receptors (GPCRs) as potential CHH receptors, no validation through binding experiments has been carried out...

Attempting to differentiate phenotypic variation caused by environmentally-induced alterations in gene expression from that caused by actual allelic differences can be experimentally difficult. Environmental variables must be carefully controlled and then interindividual genetic differences ruled out as sources of phenotypic variation. We investigated phenotypic variability of cardiorespiratory physiology as well as biometric traits in the parthenogenetically-reproducing marbled crayfish Procambarus virginalis Lyko, 2017, all offspring being genetically identical clones...

Detection of environmental cues is essential for all vertebrates and is typically established by the olfactory epithelium and olfactory sensory neurons (OSNs). In fishes, microvillous and ciliated OSNs are the principal types, typically detecting amino acids and bile salts, respectively. Activation of OSN receptors by specific ligands initiate downstream signal processing often leading to behavioural responses. In this study we used electrophysiological and behavioural techniques to evaluate olfactory detection and behaviour in juvenile lake sturgeon Acipenser fulvescens in response to hatchery- and natural dietary cues...

Diet shifts can alter tissue fatty acid composition in birds, which is subsequently related to metabolic patterns. Eicosanoids, short-lived fatty acid-derived hormones, have been proposed to mediate these relationships but neither baseline concentrations nor the responses to diet and exercise have been measured in songbirds. We quantified a stable derivative of the vasodilatory eicosanoid prostacyclin in the plasma of male European Starlings (Sturnus vulgaris, N = 25) fed semisynthetic diets with either high (PUFA) or low (MUFA) amounts of n6 fatty acid precursors to prostacyclin...

Postprandial kinetics of genes expression of gastric (chitinase, pepsinogen) and intestinal (alkaline phosphatase, maltase) digestive enzymes and nutrient transporters (peptide transporter 1, sodium-glucose transporter 1), Brush Border Membrane (BBM) enzymes activity (alkaline phosphatase, leucine aminopeptidase, maltase, saccharase) and blood biochemistry (triglycerides, cholesterol, protein, albumin, glucose, amino acids) through NMR spectroscopy, were investigated in rainbow trout (Oncorhynchus mykiss) fed a commercial aquafeed...