Journal of Comparative Physiology B-Biochemical Systems and Environmental Physiology最新文献

{"title":"Seasonal indices of nutrition and stress in a northern population of snowshoe hares.","authors":"Claire Montgomerie, Marianne Lian, Greg Breed, Mandy Keogh, Knut Kielland","doi":"10.1007/s00360-025-01617-0","DOIUrl":"https://doi.org/10.1007/s00360-025-01617-0","url":null,"abstract":"<p><p>Cyclic changes in snowshoe hare (Lepus americanus) fecundity have been attributed to changes in winter forage availability and predation pressure. Disentangling how nutrition and predation pressure affect snowshoe hare physiology is complex. As an herbivore of the northern boreal forests, snowshoe hares cope with extreme seasonal changes in diet, ambient temperature, and energy demands. We examined seasonal variation in the body condition index, blood biomarkers indicative of nutritional status, and fecal cortisol metabolite concentrations, in snowshoe hares across five ecologically distinct times of year in relation to adult survival rates. Snowshoe hares sampled from a high-density population in northern Alaska during 2018 showed decreases in survival and in plasma concentrations of total protein (TP), blood urea nitrogen (BUN), hematocrit (Hct), Chloride (Cl) and glucose during March and October. Increased survival and concentrations of Cl, TP, BUN, Hct, sodium (Na) and glucose were observed during August. Decreases in mass and survival from August to October suggest limited forage. Increases in TP, BUN, Hct and glucose in December suggest higher metabolic turnover. Fecal cortisol concentrations were not significantly associated with seasonal nutritional condition. A two-fold increase in mean cortisol was observed during August, potentially associated with energetically costly processes such as increased movement and reproduction. This work provides seasonal observations of snowshoe hare plasma biochemical values (N = 164) indicative of nutritional status, and supports the idea of using a collective biomarker approach to advance our understanding of how seasonality may play a role in snowshoe hare physiology.</p>","PeriodicalId":56033,"journal":{"name":"Journal of Comparative Physiology B-Biochemical Systems and Environmental Physiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144053477","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":"Cardiac mitochondria function in embryonic and 1-year old American alligators, Alligator mississippiensis, is not altered by hypoxic incubation or an acute anoxic challenge.","authors":"Janna Crossley, Jessica D Rippamonti, Dane A Crossley, Edward M Dzialowski","doi":"10.1007/s00360-025-01618-z","DOIUrl":"https://doi.org/10.1007/s00360-025-01618-z","url":null,"abstract":"<p><p>Hypoxic conditions naturally occur in nests of egg laying reptiles including the American alligator, Alligator mississippiensis. The effects of developmental hypoxia have been delineated in several studies of this species, with changes in cardiovascular function persisting into juvenile life. However, several questions regarding the effects of developmental hypoxia remain. In this study we designed a series of experiments to quantify the effects of developmental hypoxia on permeabilized cardiac muscle fiber mitochondrial respiration, reactive oxygen species production, and response to acute anoxia in American alligators. Alligator eggs were incubated in 21% O₂ (normoxia) or 10% O₂ (hypoxia) at 30 °C beginning on day 14 of a 72-day incubation period through hatching. Animals were studied at two ages, at 90% of incubation and 1-year post hatching. Mitochondrial respiration and ROS production under leak and oxidative phosphorylation states were measured in permeabilized cardiac muscle fibers with high-resolution respirometry coupled with fluorometry. To examine the response of mitochondria to acute anoxia and subsequent reoxygenation, permeabilized cardiac muscle fibers were exposed to 20 min of anoxia, followed by reoxygenation during measurement of mitochondria respiration and ROS production. Hypoxic incubation resulted in a decrease in embryos mass which was maintained through the first year of juvenile life. Hypoxic incubation had no effect on cardiac mitochondria respiration or ROS production at either 90% of incubation or 1-year post hatching. After exposure to anoxia for 20 min, the rate of mitochondria respiration did not differ between the pre-anoxia respiration levels for all animals tested. There was no change in ROS production observed upon reoxygenation of the permeabilized cardiac muscle. Our results suggest that hypoxic incubation has little influence on cardiac myocyte mitochondrial physiology in the developing alligator and the cardiac mitochondria are resistant to acute bouts of anoxic exposure.</p>","PeriodicalId":56033,"journal":{"name":"Journal of Comparative Physiology B-Biochemical Systems and Environmental Physiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144036289","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":"Differences in fur cortisol levels of three migratory bats.","authors":"Dana M Green, Christine Gilman, Gabriela Mastromonaco, Erin F Baerwald, R Mark Brigham","doi":"10.1007/s00360-025-01609-0","DOIUrl":"https://doi.org/10.1007/s00360-025-01609-0","url":null,"abstract":"<p><p>Understanding how organisms respond to their environments is challenging, especially due to the complex processes related to metabolism, energetics, and reproduction. Glucocorticoids (GCs) are metabolic hormones that provide insight into internal process and may trigger a variety of behaviors. To understand how changes to the environment influence wildlife, we must ideally measure levels of GCs in wildlife populations that are relatively undisturbed by anthropogenic change or natural disaster. In free-ranging mammals, cortisol is a primary GC hormone and can be measured in fur. Bats are the only mammalian order to have evolved true flight and, in North America, most species of bats are in the family Vespertilionidae. By measuring cortisol levels during energetically expensive periods of an animal's life history, we can document 'baseline levels' related to different life stages, sexes, and ages. We collected fur from hoary (Lasiurus cinereus), silver-haired (Lasionycteris noctivagans), and little-brown Myotis (Myotis lucifugus) bats from southern Alberta and Saskatchewan. Herein we report their baseline levels of fur cortisol, noting interspecific differences between species. We found that bats known to migrate longer distances had higher levels compared to bats that migrate shorter distances, and then hibernate. Interestingly, we found no differences in levels between the reproductive stages for any species. Finally, both silver-haired and hoary bats show a strong difference in fur cortisol levels between adults and juveniles. We suggest that the elevated levels are likely associated with events for mothers during lactation which are then incorporated into the pups' fur while nursing.</p>","PeriodicalId":56033,"journal":{"name":"Journal of Comparative Physiology B-Biochemical Systems and Environmental Physiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144043357","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":"Prolonged 5-week and 12-week chronic stress differentially modulates CNS expression of pro- and anti-neuroinflammatory biomarkers, brain monoamines and affective behavior in adult zebrafish.","authors":"Maria M Kotova, Sahil V Amikishiev, Kirill V Apukhtin, David S Galstyan, Murilo S de Abreu, Adam Michael Stewart, Longen Yang, Allan V Kalueff","doi":"10.1007/s00360-025-01613-4","DOIUrl":"https://doi.org/10.1007/s00360-025-01613-4","url":null,"abstract":"<p><p>Chronic stress is a major cause of affective pathogenesis, such as anxiety and depression. Experimental animal models, including rodents and zebrafish, are a valuable tool for translational neuroscience research focusing on stress-related brain disorders. Here, we examined the effects of 5- and 12-week chronic unpredictable stress (CUS5 and CUS12) on zebrafish behavior, whole-body cortisol and neuroinflammation-related biomarker gene expression, including markers of pro-inflammatory microglia (NOS2a, COX2, P75NTR) and astroglia (C3, GBP), and markers of anti-inflammatory microglia (ARG-1, CD206) and astroglia (S100a10, PTX). We also assessed stress-induced changes in brain monoamine levels and brain-blood-barrier permeability. Overall, CUS5 induced anxiety-like behavior, accompanied by elevated CNS pro-inflammatory marker gene expression, cortisol signaling and norepinephrine levels. In contrast, CUS12 induced depression-like behavior, accompanied by lowered cortisol levels, impaired serotonin turnover and activated anti-inflammatory biomarker gene expression, as well as upregulated histone deacetylase 4 gene (suggesting the involvement of epigenetic regulation). Collectively, this confirms the importance of stress duration as a key factor in the development of stress-related disorders in zebrafish models, and further implicates pro- and inti-inflammatory neuroglia in affective pathogenesis.</p>","PeriodicalId":56033,"journal":{"name":"Journal of Comparative Physiology B-Biochemical Systems and Environmental Physiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144029693","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":"Mammalian birth versus arousal from hibernation: thyroid hormones, common regulators of metabolic transition?","authors":"Melanie Heidkamp, Annika Herwig, Dominique Singer","doi":"10.1007/s00360-025-01611-6","DOIUrl":"https://doi.org/10.1007/s00360-025-01611-6","url":null,"abstract":"<p><p>Mammalian birth and arousal from hibernation are both endogenously regulated transitional events, characterized by an increase in metabolic rate (MR) and onset of thermogenesis. Thyroid hormones (THs) are known to be key regulators of metabolic and thermogenic activity. To explore the similarities and differences in the role of THs during mammalian birth as opposed to arousal from hibernation, a comprehensive review is given of the levels and kinetics of serum thyrotropin-releasing hormone (TRH), thyroid stimulating hormone (TSH), thyroxine (T₄), triiodothyronine (T₃), and reverse triiodothyronine (rT₃) in hibernating mammals upon arousal and in mammalian neonates at birth. The results for arousal are more heterogeneous than those for birth, reflecting different hibernation patterns between species as well as varying sampling times and methods. Overall, serum TRH concentrations were found to be decreased, TSH unchanged, and T₄, T₃, and rT₃ mostly increased. In contrast, the data for mammalian birth show a marked increase in serum levels of TRH, TSH, T₄, and T₃, particularly in human neonates, with inconsistent results for rT₃. In conclusion, both during arousal from hibernation and mammalian birth, THs play a critical yet not exclusive role in metabolic transition. In hibernators, the metabolic effects of THs appear to be mediated by the conversion rates in target tissues rather than by their serum levels alone, suggesting a sustained readiness for arousal. This contrasts with mammalian newborns, who at the beginning of their autonomous life experience the first activation of their thyroid gland, resulting in a transitory \"hyperthyroid\" state.</p>","PeriodicalId":56033,"journal":{"name":"Journal of Comparative Physiology B-Biochemical Systems and Environmental Physiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144045455","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":"Environmental temperature and immune activation during development: effects on organ growth in juvenile degus.","authors":"Natalia Ramirez-Otarola, Bernardita Riquelme, Pablo Sabat","doi":"10.1007/s00360-025-01614-3","DOIUrl":"https://doi.org/10.1007/s00360-025-01614-3","url":null,"abstract":"<p><p>In this study, we investigated the influence of environmental temperature and immune challenge on organ and body mass in juvenile degus (Octodon degus). Using an experimental design with two temperature treatments (15 °C and 30 °C) and a lipopolysaccharide (LPS)-induced immune challenge, we measured the mass of key organs (kidney, heart, liver, spleen, lung) as well as body mass. Our results showed that temperature alone significantly affected kidney, heart, lung, and body mass, with individuals reared at 30 °C exhibiting larger organs and greater body mass, consistent with thermoneutral conditions. Immune challenge with LPS primarily affected lung mass, with challenged individuals showing larger lungs regardless of temperature. However, no significant changes were observed in spleen or liver mass, and no interactions between temperature and immune challenge were detected. These findings suggest that temperature-driven developmental plasticity plays a dominant role in shaping organ and body traits, while immune activation induces organ-specific responses. Our results highlight the importance of environmental temperature in shaping physiological traits and raise questions about the long-term effects of immune challenges and temperature interactions on wildlife health and fitness.</p>","PeriodicalId":56033,"journal":{"name":"Journal of Comparative Physiology B-Biochemical Systems and Environmental Physiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144046866","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":"Electrophysiological evidence for the right atrioventricular pacemaker ring in the reptile heart.","authors":"Valentina Prosheva, Vladimir Vityazev, Elena Lebedeva","doi":"10.1007/s00360-025-01612-5","DOIUrl":"10.1007/s00360-025-01612-5","url":null,"abstract":"<p><p>Pacemaker atrioventricular (AV) rings, continuous with the AV node, have been shown to be present in the mammalian and avian hearts. There is conspicuous lack of electrophysiological data on the cardiac pacemakers in reptiles. We aimed to characterize the AV ring in the common lizard heart for the first time using conventional microelectrode technique. Detaching the sinoatrial (SA) area unmasked pacemaking in the AV junction. In all seven studied isolated AV ring preparations, we could record action potentials (APs) with characteristic diastolic depolarization, with a slow upstroke (dV/dt _max) of 3.5 ± 0.3 V s^-1 and a low amplitude of 57.8 ± 1.3 mV. The cells with pacemaking potentiality were found to surround the atrial orifice of the right AV valve. We identified some commonalities between phenotype of right AV ring pacemaker APs and SA dominant pacemaker ones. Thus, the AV ring in the reptile heart demonstrates pacemaking activity and contains cells that resemble the electrophysiological characteristics of mammalian and avian pacemaker myocytes in AV rings surrounded the atrial orifices of AV valves.</p>","PeriodicalId":56033,"journal":{"name":"Journal of Comparative Physiology B-Biochemical Systems and Environmental Physiology","volume":" ","pages":"181-190"},"PeriodicalIF":1.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143736179","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":"Intraspecific variation in metabolic responses to diverse environmental conditions in the Malagasy bat Triaenops menamena.","authors":"Sina Remmers, K Dausmann, M Schoroth, H Rabarison, S Reher","doi":"10.1007/s00360-025-01608-1","DOIUrl":"https://doi.org/10.1007/s00360-025-01608-1","url":null,"abstract":"<p><p>Widespread species often display traits of generalists, yet local adaptations may limit their ability to cope with diverse environmental conditions. With climate change being a pressing issue, distinguishing between the general ecological and physiological capacities of a species and those of individual populations is vital for assessing the capability to adapt rapidly to changing habitats. Despite its importance, physiological variation across broad range distributions, particularly among free-ranging bats in natural environments, has rarely been assessed. Studies focusing on physiological variation among different populations across seasons are even more limited. We investigated physiological variation in the Malagasy Trident Bat Triaenops menamena across three different roost types in Madagascar during the wet and dry season, examining aspects such as energy regimes, body temperature, and roost microclimates. We focused on patterns of torpor in relation to roosting conditions. We hypothesized that torpor occurrence would be higher during the colder, more demanding dry season. We predicted that populations roosting in more variable microclimates would expend less energy than those in mores stable ones due to more frequent use of torpor and greater metabolic rate reductions. Our findings highlight complex thermoregulatory strategies, with varying torpor expression across seasons and roosts. We observed an overall higher energy expenditure during the wet season but also greater energy savings during torpor in that season, regardless of roost type. We found that reductions in metabolic rate were positively correlated with greater fluctuations in ambient conditions, demonstrating these bats' adaptability to dynamic environments. Notably, we observed diverse torpor patterns, indicating the species' ability to use prolonged torpor under extreme conditions. This individual-level variation is crucial for adaptation to changing environmental conditions. Moreover, the flexibility in body temperature during torpor suggests caution in relying solely on it as an indicator for torpor use. Our study emphasizes the necessity to investigate thermoregulatory responses across different populations in their respective habitats to fully understand a species' adaptive potential.</p>","PeriodicalId":56033,"journal":{"name":"Journal of Comparative Physiology B-Biochemical Systems and Environmental Physiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143671622","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":"The impact of melatonin and its agonist on blood pressure and serum endothelin-1 in continuous light and pinealectomized rats.","authors":"Evan B Othman, Ismail M Maulood, Nazar M Shareef Mahmood","doi":"10.1007/s00360-025-01610-7","DOIUrl":"https://doi.org/10.1007/s00360-025-01610-7","url":null,"abstract":"<p><p>The present study investigates the roles of melatonin (MEL) and its agonist ramelteon (RAM) on blood pressure regulation, nitric oxide (NO), and oxidative stress and plasma endothelin-1(ET-1) levels in continuous light exposure and pinealectomized conditions. This study includes two experiments. The first experiment involved control, continuous light emitting diode (LED) exposure, continuous LED + MEL administration, and continuous LED + RAM. The second experiment included control, pinealectomy, pinealectomy + MEL administration, pinealectomy + RAM administration, and pinealectomy + continuous LED exposure. The present results showed significant increase of systolic blood pressure (SBP) of continuous LED exposure group, pinealectomy, and pinealectomy with continuous LED exposure. On the contrary, MEL and RAM both decreased SBP. Additionally, the continuous LED exposure considerably increased malondialdehyde (MDA). However, MEL increased both plasma ET-1 slightly and ET-1 significantly but RAM dramatically increased ET-1. While, both of MEL and RAM decreased MDA. In the second experiment, while MDA dramatically increased after pinealectomy and pinealectomy with LED illumination, ET-1 and NO were only a little reduced. Melatonin elevated plasma ET-1 and NO significantly. While, MDA was greatly reduced by MEL but not by RAM. The results suggested that MEL and RAM could attenuate SBP mostly via increasing NO generation and oxidative stress reduction.</p>","PeriodicalId":56033,"journal":{"name":"Journal of Comparative Physiology B-Biochemical Systems and Environmental Physiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631085","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":"Transcriptomic insights into the low-salinity tolerance of the sea louse Caligus elongatus.","authors":"Andreas Borchel, Frank Nilsen","doi":"10.1007/s00360-025-01606-3","DOIUrl":"10.1007/s00360-025-01606-3","url":null,"abstract":"<p><p>Caligus elongatus is a marine copepod ectoparasite on a wide variety of fish species. It has also been observed on fish farms cultivating Atlantic salmon and reports shows that this parasite can be a problem for the industry and for the fish's welfare. Freshwater is used as one of the non-medical treatment methods against the salmon louse (Lepeophtheirus salmonis). However, the efficacy of freshwater treatment against C. elongatus is still unknown. This study aims to fill this gap by examining the salinity tolerance limits of both adult and copepodid life stages of C. elongatus. Our findings reveal that detached adult C. elongatus exhibit low tolerance to reduced salinity, with mortality occurring within hours at salinities below 20 ppt. In contrast, copepodid stages demonstrated a slightly higher tolerance, surviving at salinities as low as 15 ppt for one day. Adult lice attached to a host quickly detached from the fish as soon as the salinity was lower than 20 ppt, suggesting that freshwater delousing might be effective in this species. To further understand the genetic basis of acclimation to reduced salinities, we performed RNA-sequencing to assemble the first transcriptome of this species and identify differentially expressed genes. Several genes regulated upon low-salinity transfer were identified. These include genes involved in proline metabolism, energy metabolism, and the transport of various ions and betaine, an osmolyte. The potential roles of these genes in salinity acclimation are discussed within an evolutionary context, providing valuable insights into the survival mechanisms of C. elongatus under low-salinity conditions.</p>","PeriodicalId":56033,"journal":{"name":"Journal of Comparative Physiology B-Biochemical Systems and Environmental Physiology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143525326","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}