Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology最新文献

{"title":"Dealing with the heat: Assessing heat stress in an Arctic seabird using 3D-printed thermal models","authors":"Fred Tremblay ,&nbsp;Emily S. Choy ,&nbsp;David A. Fifield ,&nbsp;Glenn J. Tattersall ,&nbsp;François Vézina ,&nbsp;Ryan O'Connor ,&nbsp;Oliver P. Love ,&nbsp;Grant H. Gilchrist ,&nbsp;Kyle H. Elliott","doi":"10.1016/j.cbpa.2025.111880","DOIUrl":"10.1016/j.cbpa.2025.111880","url":null,"abstract":"<div><div>The Arctic is warming at four times the global average rate and most studies have focused on the indirect (e.g., changes in food web) rather than the direct effects of climate change. However, as Arctic animals often have low capacity to dissipate heat, the direct effect of warming could impact them significantly (heat stress). To study heat stress, biophysical models have been used in many species to estimate operative temperature (Te, integrated temperature of the thermal environment experienced by an individual). Here, we developed biophysical models of an Arctic seabird, the thick-billed murre (<em>Uria lomvia</em>). We demonstrated that 3D-printed painted models perform similarly to the more traditionally used feather-covered models. We deployed our models on Coats Island, Nunavut, Canada to study heat stress, which occurs in murres when operative temperature is above 21.2 °C (the temperature at which evaporative water loss (EWL) rates increase to maintain a constant body temperatures). Murre operative temperatures ranged from 5.5 °C to 46.5 °C despite ambient temperatures never exceeding 24.7 °C (range: 3.4–24.7 °C), and murres experienced heat stress on 61 % of the days during the breeding season (range: 24–85 %). Using known equations of EWL as a function of temperature, we estimated that murres lost 3.79 % to 4.61 % of their body mass in water daily. Our study confirms the physiological challenges faced by Arctic seabirds during the breeding season, while also demonstrating the value of biophysical models as non-invasive tools to study the effects of heat stress on seabirds.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"306 ","pages":"Article 111880"},"PeriodicalIF":2.1,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144113110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metabolic responses to thermal ramping in two endemic eurybathic amphipods of the genus Ommatogammarus from ancient Lake Baikal","authors":"Yulia Shirokova ,&nbsp;Ekaterina Telnes (Madyarova) ,&nbsp;Andrey Mutin ,&nbsp;Yaroslav Rzhechitskiy ,&nbsp;Zhanna Shatilina ,&nbsp;Inna Sokolova ,&nbsp;Maxim Timofeyev","doi":"10.1016/j.cbpa.2025.111881","DOIUrl":"10.1016/j.cbpa.2025.111881","url":null,"abstract":"<div><div>Lake Baikal harbors freshwater profundal amphipods, including the eurybathic species <em>Ommatogammarus flavus</em> and <em>O. albinus</em>. <em>O. flavus</em> occupies shallower habitats, including the littoral zone, which is subject to greater temperature variability. Consequently, <em>O. flavus</em> may demonstrate a higher degree of tolerance to temperature fluctuations in comparison with <em>O. albinus</em>. We compared the metabolic responses of these two amphipod species to thermal ramping. Specimens were collected from a range of depths and acclimated to a temperature of 4 °C. They were then subjected to controlled temperature up- and downshifts to assess the parameters of tissue energy status, antioxidant enzyme activity, and survival. <em>O. flavus</em> showed a higher degree of tolerance to warming than the deeper-dwelling <em>O. albinus</em>, while both species were resilient to temperature decreases. The depth of sampling had a minor effect on glycogen levels in <em>O. flavus</em> as well as catalase and glutathione S-transferase activity in <em>O. albinus</em> but had no effect on survival during experimental warming. Glucose level was shown to be the most sensitive biochemical marker to temperature variations, indicating that it could be used as a stress indicator for Baikal deep-water amphipods. This finding might provide insight into their adaptability to ambient temperature fluctuations.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"306 ","pages":"Article 111881"},"PeriodicalIF":2.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144087090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of Transient Receptor Potential Cation Channel subfamily Vanilloid 4 (TRPV4) in chub mackerel: Role in low-salinity acclimation and reproductive implications","authors":"Kyle Dominic Barnuevo ,&nbsp;Nguyen The Vuong ,&nbsp;Sipra Mohapatra ,&nbsp;Oga Sato ,&nbsp;Hironori Katoh ,&nbsp;Takehiko Itoh ,&nbsp;Naoki Nagano ,&nbsp;Michiya Matsuyama ,&nbsp;Tapas Chakraborty ,&nbsp;Kohei Ohta","doi":"10.1016/j.cbpa.2025.111879","DOIUrl":"10.1016/j.cbpa.2025.111879","url":null,"abstract":"<div><div>Salinity plays a crucial role in fish physiology, including osmoregulation, metabolism, growth, reproduction, and disease resistance. In this study, we characterized the Transient Receptor Potential Cation Channel Subfamily Vanilloid 4 (<em>trpv4</em>) gene and investigated the effects of low-salinity conditions on its expression in various tissues of chub mackerel (<em>Scomber japonicus</em>), an economically important aquaculture species. The <em>trpv4</em> open reading frame (ORF) consists of 2616 nucleotides and encodes an 872-amino acid protein. It shares up to 94.01 % phylogenetic similarity with <em>Thunnus maccoyii</em> and possesses 6 transmembrane domains highly conserved with human TRPV4. <em>Trpv4</em> was widely distributed across most organs and showed significant sex-biased expression. <em>In situ</em> hybridization data showed that <em>trpv4</em> was explicitly expressed in various parts of the pituitary, from <em>pars intermedia</em> (PI) to <em>rostral pars distalis</em> (RPD) where it colocalized with <em>prolactin 1</em> (<em>prl1</em>) in RPD. Furthermore, exposure to decreasing salinity from 35 ppt to 10 ppt demonstrated a significant upregulation of <em>trpv4</em> transcription in the pituitary, gill, skin, and gonad under low-salinity conditions. Although <em>prl1</em> was upregulated, <em>follicle-stimulating hormone beta subunit</em> (<em>fshb</em>) expression was decreased in the pituitaries of low-salinity groups. These findings suggest that <em>trpv4</em> is regulated by salinity in chub mackerel and may play a role in reproductive responses to salinity changes. Overall, these results highlight the characterization of <em>trpv4</em> in marine fish and its potential roles in osmoregulation, as well as in transmitting low-salinity signals to reproduction-related organs. The involvement of the brain–pituitary–gonad axis in this response warrants further investigation.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"306 ","pages":"Article 111879"},"PeriodicalIF":2.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144087088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal regulation and PIP2 dependence of inwardly rectifying potassium channels (Kir) in retinal horizontal cells of goldfish (Carassius auratus)","authors":"Shilo L. Rousseau ,&nbsp;Michael G. Jonz","doi":"10.1016/j.cbpa.2025.111877","DOIUrl":"10.1016/j.cbpa.2025.111877","url":null,"abstract":"<div><div>Many species face extreme changes in their environment throughout the year, during which time they must modify their neuronal activity to survive. Horizontal cells (HCs) are interneurons in the goldfish (<em>Carassius auratus</em>) retina that demonstrate seasonal changes in membrane structure and excitability. Excitability in neurons is strongly influenced by inwardly rectifying potassium channels (K_ir), suggesting that K_ir in HCs may be a candidate for modulating seasonal changes. K_ir channel function depends on the plasma membrane phospholipid, PIP₂, to which it is bound. However, it remains unclear whether the PIP₂-K_ir channel interaction contributes to regulation of K_ir in goldfish HCs. Using perforated patch voltage-clamp recording, we identified K_ir current by inhibition with cesium (Cs⁺) and compared peak inward K_ir current density in goldfish HCs isolated during the summer and winter months. Significantly more current was inhibited by Cs⁺ in winter HCs, suggesting more open K_ir channels. To examine the role of PIP₂ in regulating K_ir, tamoxifen or activation of phospholipase C by m-3M3FBS were used to disrupt the PIP₂-K_ir channel interaction and subsequently reduced K_ir current. Spermine, through strengthening the PIP₂-K_ir interaction, reduced the inhibitory effects of tamoxifen. Additionally, in current-clamp recordings, HCs treated with m-3M3FBS displayed a depolarized membrane potential (V_m) and a decrease in spontaneous Ca²⁺-based action potentials. We demonstrate that K_ir activity is seasonally regulated in goldfish HCs and that K_ir is dependent upon PIP₂. Our results suggest PIP₂ as a potential target for coordinating seasonal changes in the activity of neurons in the goldfish retina.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"306 ","pages":"Article 111877"},"PeriodicalIF":2.1,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144060367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anorexigenic and anxiogenic effects of the plasticiser DEHP (di-2-ethylhexyl phthalate) in goldfish: Involvement of PPAR signalling and feeding-related neuropeptides","authors":"Lisbeth Herrera-Castillo,&nbsp;Claudia Hernández-Villasevil,&nbsp;André Barany,&nbsp;Miguel Gómez-Boronat,&nbsp;Esther Isorna,&nbsp;Nuria de Pedro","doi":"10.1016/j.cbpa.2025.111878","DOIUrl":"10.1016/j.cbpa.2025.111878","url":null,"abstract":"<div><div>Di-2-ethylhexyl phthalate (DEHP), a widely used plasticiser, is a pervasive environmental contaminant with potential detrimental effects on aquatic organisms. The objective of this study was to provide an integrative analysis of how DEHP alters energy balance, temporal homeostasis and fish welfare — interrelated aspects critical to animal survival — to address critical gaps in our understanding of its toxicological effects. Goldfish (<em>Carassius auratus</em>) were chronically (14 days) treated with DEHP. Energy balance was assessed through locomotor activity, metabolic rate, feed intake, and growth indices. Daily of locomotor and metabolic rate rhythms were examined to explore potential circadian disruptions. Anxiety-like behaviours were also examined to assess welfare. DEHP decreased feed intake and food-anticipatory activity (FAA), suggesting an anorexigenic effect, which may have been mediated by increased expression of anorexigenic genes in the hypothalamus and liver, along with decreased expression of orexigenic <em>npy</em> (neuropeptide Y) gene in the hypothalamus. Growth parameters remained unchanged, probably due to compensatory reductions in energy expenditure, as indicated by decreased locomotor activity and metabolic rate. Daily rhythms in these two parameters were preserved, suggesting no disruption in temporal homeostasis. DEHP increased hepatic expression of peroxisome proliferator-activated receptor (PPAR)-related genes, suggesting that PPARs activation is a potential mode of action for DEHP in fish. Anxiety levels were elevated, as evidenced by increased thigmotaxis and scototaxis in behavioural tests, which may be mediated by changes in hypothalamic neuropeptides. These findings highlight the adverse effects of DEHP on energy regulation and animal welfare, providing novel insights into its broader physiological consequences in fish.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"306 ","pages":"Article 111878"},"PeriodicalIF":2.1,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Complementary DNA (cDNA) cloning and expression analysis of selenium glutathione peroxidase (Se-GPx) and glutathione S-transferases (GST) 1 in red claw crayfish (Cherax quadricarinatus)","authors":"Jia-Han Liu ,&nbsp;Jun-Tao Li ,&nbsp;Yao-Peng Lu ,&nbsp;Pei-Hua Zheng ,&nbsp;Ze-Long Zhang ,&nbsp;Xiu-Xia Zhang ,&nbsp;Chi Xu ,&nbsp;Zi-Hang Yu ,&nbsp;Xiu-Ying Yang ,&nbsp;Hui Guo ,&nbsp;Jian-An Xian","doi":"10.1016/j.cbpa.2025.111876","DOIUrl":"10.1016/j.cbpa.2025.111876","url":null,"abstract":"<div><div>Selenium glutathione peroxidase (Se-GPx) and Glutathione S-transferases (GST) are crucial parts of cellular detoxification systems that protect cells from reactive oxygen species (ROS). In this study, cDNA sequences of CqGST1 and CqSe-GPx were cloned from red claw crayfish (<em>Cherax quadricarinatus</em>). The molecular masses of the predicted protein are 25.36 and 21.49 kDa, respectively. CqGST1 and CqSe-GPx have open reading frames (ORFs) of 657 bp and 570 bp and encode peptides of 218 and 189 amino acids, respectively. Sequence alignment showed that the amino acid sequence of CqSe-GPx identity with that of the <em>Exopalaemon carinicauda</em>, <em>Penaeus japonicus</em>, <em>Macrobrachium rosenbergii</em>, <em>Penaeus monodon</em>, <em>Litopenaeus vannamei</em>, <em>Macrobrachium nipponense</em> and <em>Scylla paramamosai</em>. The amino acid sequence of CqGST1 identity with <em>Procambarus clarkii</em>, <em>Stegastes partitus</em>, <em>Gavialis gangeticus</em>, <em>Alligator mississippiensis,</em> and L. <em>vannamei</em>. The qRT-PCR results showed that CqSe-GPx and CqGST1 were found in a variety of tissues, with the highest hemolymph expression and the weakest expression in muscle, eye stalk, and heart. The expression levels of CqSe-GPx and CqGST1 in the hepatopancreas and gills of crayfish were detected under ammonia-N and microcystins-LR stresses. The expression of CqSe-GPx was induced in the hepatopancreas of crayfish during MC-LR stress, and gill CqSe-GPx expression levels were induced at 6 and 12 h. Hepatopancreas and gill CqSe-GPx expression levels were significantly up-regulated during ammonia-N at 24 and 48 h, respectively. The CqGST1 expression levels were significantly elevated in the hepatopancreas and gill during MC-LR or ammonia-N stress. Under ammonia stress, hepatopancreas and gill GST expression levels of crayfish showed a decreasing and then increasing trend. Hepatopancreas and gill CqGST1 expression levels of crayfish were significantly up-regulated at 12, 24, and 48 h of ammonia-N stress. These results suggest that CqSe-GPx and CqGST1 play an important role in protecting <em>C. quadricarinatus</em> from ammonia-N and MC-LR stress and provide a theoretical basis for further study on the molecular mechanism of response to environmental stress on crayfish.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"306 ","pages":"Article 111876"},"PeriodicalIF":2.1,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144029701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acidification affects the early development of Colombian endemic fish Prochilodus magdalenae","authors":"Villamizar Natalia ,&nbsp;Guardiola Jose Luis ,&nbsp;Cruz-Botto Sara ,&nbsp;Rodríguez Hector Alejandro ,&nbsp;Reyes-Bermúdez Alejandro ,&nbsp;Noisette Fanny","doi":"10.1016/j.cbpa.2025.111875","DOIUrl":"10.1016/j.cbpa.2025.111875","url":null,"abstract":"<div><div>There is a significant knowledge gap regarding the acidification of freshwater ecosystems and its effects on biological systems. The bocachico (<em>Prochilodus magdalenae</em>), an endemic and migratory species vital to Colombia's inland fisheries, is currently classified as vulnerable. This study evaluated the impact of different pH levels (6.2, 7.2, and 7.6), previously recorded in the species' natural habitat, on its early development. Using an automated IKS Aquastar system, embryo incubation and larval maintenance were monitored from 0 to 5 days post-fertilization, assessing development, hatching, and survival at both organismal and transcriptional levels. Embryos exposed to pH 6.2 showed delayed development within 4 h post-fertilization, the lowest hatching rate (68.33 ± 3.13 %), and survival (23.88 ± 4.53 %), along with the highest incidence of malformations (37.80 ± 4.4 %). The pH 7.6 group also showed adverse effects, but to a lesser extent. Transcriptome analysis revealed a distinct molecular response in the pH 6.2 group, identifying 1214 differentially expressed genes related to early development, ossification, organ formation, sensory systems, and cellular processes. The findings indicate that pH fluctuations previously observed in the species' natural environment significantly affect <em>P. magdalenae</em> during early life stages, which raises serious concerns about the long-term viability of this endemic species and the sustainability of the artisanal fisheries that depend on it.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"306 ","pages":"Article 111875"},"PeriodicalIF":2.1,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143935966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Response of Atlantic salmon to long-term sustained aerobic training at suboptimum elevated temperature: Cardiac anatomy, aerobic performance, and growth implications","authors":"Marco Foddai ,&nbsp;Chris G. Carter ,&nbsp;Andrew T. Wood ,&nbsp;Kelli C. Anderson ,&nbsp;Jayson M. Semmens","doi":"10.1016/j.cbpa.2025.111874","DOIUrl":"10.1016/j.cbpa.2025.111874","url":null,"abstract":"<div><div>Sustained aerobic training is suggested to enhance cardiac performance and growth in farmed salmonids, but its effects under suboptimum elevated temperatures remain unclear. This study examined whether continuous training at different temperatures could improve growth and whether it influenced cardiac performance at a suboptimum elevated temperature in a context relevant to offshore aquaculture. Atlantic salmon were reared for 90 days at 15 °C (control temperature) and 20 °C (suboptimum elevated temperature), with either continuous aerobic swimming (trained: 0.45 m.s⁻¹) or standard conditions (untrained: 0.18 m.s⁻¹). Growth and feed intake were assessed at both temperatures, while cardiac and metabolic parameters were measured only at 20 °C.</div><div>At 15 °C, trained fish exhibited increased feed intake, but this did not translate into improved growth. At 20 °C, neither feed intake nor growth improved with training. Swim-tunnel respirometry at 20 °C revealed no significant differences in aerobic performance between trained and untrained fish, although trained fish exhibited lower interindividual variability in metabolic and swimming parameters. While training increased relative ventricular mass (RVM), indicating potential cardiac remodelling, this did not result in improved metabolic performance.</div><div>These findings underscore the complexity of physiological responses to exercise and temperature in salmon aquaculture. While continuous aerobic training induced minor cardiac adaptations, its impact on growth and performance was limited, particularly at suboptimum elevated temperatures. This research provides valuable insights into how Atlantic salmon may respond to offshore farming environments, with specific relevance to Tasmania's aquaculture industry.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"306 ","pages":"Article 111874"},"PeriodicalIF":2.1,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143906312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cutaneous water loss and epidermal lipid content in lanceheads (Crotalinae: Bothrops)","authors":"Clara Carrero C. Casetta ,&nbsp;Yanca A. Salomoni ,&nbsp;Nathie M. Batista ,&nbsp;Sávio S. Sant' Anna ,&nbsp;Daniel R. Stuginski","doi":"10.1016/j.cbpa.2025.111872","DOIUrl":"10.1016/j.cbpa.2025.111872","url":null,"abstract":"<div><div>Cutaneous evaporation is the primary route of water loss in snakes. Species from arid environments typically show lower cutaneous water loss (CWL) rates due in part to higher epidermal lipid content. However, past comparative studies have used distantly related taxa or lacked phylogenetic comparative methods, limiting their conclusions. We measured CWL and lipid content (LC) in shed skins of eight lancehead species (<em>Bothrops</em>) from habitats with varying canopy coverage. Using phylogenetic comparative methods, we examined the effects of canopy coverage, snout-vent length (SVL), sex, and species on CWL and assessed its correlation with LC. Our results show that canopy coverage significantly influences CWL, independent of phylogeny. Snakes from open habitats exhibited lower CWL rates than those restricted to forests, which showed greater individual variation. Species from the most xeric habitat (Caatinga) displayed the lowest CWL. Neither sex nor SVL affected CWL, and phylogenetic signal was negligible (λ ≈ 0), suggesting weak phylogenetic constraints. CWL and LC were inversely correlated, with LC higher in open-habitat species. These findings indicate that habitat type, particularly canopy coverage, drives interspecific variation in CWL among closely related species, while phylogenetic effects are more relevant at higher taxonomic levels. Lipid content in the epidermis plays a critical role in regulating CWL, though differences in lipid composition may also contribute.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"306 ","pages":"Article 111872"},"PeriodicalIF":2.1,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fasting elicits immune modulation and leukocyte redistribution in bullfrogs (Lithobates catesbeianus)","authors":"Aymam C. de Figueiredo ,&nbsp;Débora M.A. Prado ,&nbsp;Felipe R. Floreste ,&nbsp;Patrício G. Garcia Neto ,&nbsp;Fernando R. Gomes ,&nbsp;José E. de Carvalho","doi":"10.1016/j.cbpa.2025.111873","DOIUrl":"10.1016/j.cbpa.2025.111873","url":null,"abstract":"<div><div>An integrated range of behavioral, physiological, and biochemical adjustments reduces metabolic expenditure and energy utilization during fasting to maintain homeostasis. In order to cope with these adjustments, several vertebrates can modulate immune function and corticosterone secretion while fasting to save energy. However, in ectothermic animals that can fast for longer periods due to their low metabolic rate, the underlying corticosterone and immune modulation is still not well understood. This study aimed to investigate corticosterone and immune modulation during fasting in the bullfrog (<em>Lithobates catesbeianus</em>). Bullfrogs were divided into two treatments: a ‘control group’, fed twice a week with fish feed for 31 days; and a ‘fasting group’, which remained fasting for 31 days. On the 31st day of experiment, blood was collected to measure corticosterone plasma levels and immune function (neutrophil/lymphocyte ratio, plasma bacterial killing ability - BKA, and hemagglutination) variables. Fasting did not affect corticosterone plasma levels but increased neutrophil/lymphocyte ratio and hemagglutination, while BKA was decreased. In this way, fasting modulates the innate immune function in male bullfrogs by increasing the NL ratio and hemagglutination activity while reducing BKA, without affecting plasma CORT levels or fat body mass content. Thus, 31 days of fasting induces blood immune cell redistribution and an immunomodulatory response without significant activation of the HPI axis or depletion of energy stores.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"306 ","pages":"Article 111873"},"PeriodicalIF":2.1,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143896101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}