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

{"title":"Cell-specific organization and paralog divergence of erythropoietin signaling in Atlantic salmon.","authors":"T Hjemsæter, I B Johansen, P G Fjelldal, D J Macqueen, S F Nørstebø, E O Koppang, H Bjørgen","doi":"10.1016/j.cbpa.2026.112082","DOIUrl":"https://doi.org/10.1016/j.cbpa.2026.112082","url":null,"abstract":"<p><p>Erythropoietin (EPO) is the main hormonal regulator of erythropoiesis in vertebrates and also mediates non-hematopoietic functions. Despite extensive characterization in mammals, the cellular sources and targets of EPO signaling remain poorly defined in non-mammalian vertebrates. The Atlantic salmon provides a valuable model to investigate paralog-specific organization of EPO signaling due to a recent whole genome duplication (WGD). Here, we characterize the tissue- and cell-specific expression of paralogs encoding EPO and the erythropoietin receptor (EPOR) in Atlantic salmon (Salmo salar). Phylogenetic analysis revealed four EPO encoding paralogs retained from the teleost-specific (Ts3R) and salmonid-specific WGD (Ss4R) events, designated epoa1, epoa2, epob1 and epob2, and two Ss4R paralogs encoding EPOR, designated epora1 and epora2. In situ hybridization analysis targeting mRNA revealed that epoa2 was the predominantly expressed paralog in the heart, with cardiomyocytes as the principal source, while epob1 was the most abundant paralog in the kidney with expression mainly in tubular epithelial cells of the trunk kidney. mRNA from the epora genes was most highly expressed in erythropoietic tissues and cells but also detected in non-erythropoietic cell types. Temperature was shown to affect epoa2 mRNA expression in the heart. Collectively, these results identify the cellular sources of epo mRNA in the heart, head kidney and trunk kidney, and demonstrate paralog-specific partitioning of epo expression following the Ss4R WGD in Atlantic salmon. In addition, mRNA for epora genes was detected across a range of hematopoietic and non-hematopoietic cell types. Together, these findings provide a cell-resolved framework for understanding vertebrate EPO signaling, suggesting roles of EPO and EPOR in regulating both erythropoietic and non-hematopoietic processes.</p>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":" ","pages":"112082"},"PeriodicalIF":2.4,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149229086","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":"Early morphological and physiological parameters of survival and mortality in cultured southern flounder (Paralichthys lethostigma) larvae.","authors":"Olivia Thibault, Jennifer Butler, Paul Cason, David Hala, Lene H Petersen","doi":"10.1016/j.cbpa.2026.112081","DOIUrl":"https://doi.org/10.1016/j.cbpa.2026.112081","url":null,"abstract":"<p><p>This study focused on the relation between larval southern flounder (Paralichthys lethostigma) growth, cardiac performance, and metabolic physiology (metabolic rate, hormones). Two-way ANOVAs were performed among larvae groups that successfully survived through metamorphosis (n = 1) vs. those that succumbed to mass mortality early in development (n = 2). Larvae were monitored from 5 to 50 days post hatch (dph). The comparison of morphological and physiological parameters for the three batches for equivalent life-stages from 5 to 12 dph (n = 8-10/dph), showed specific growth rate (SGR) in the surviving larvae to be ~3-fold higher than the two failed batches. Similarly, the absolute oxygen consumption rate (AMO₂) was ~5-fold higher in the surviving batch vs. the two failed batches. In contrast, mass specific oxygen consumption rate (MO₂) and heart rate (HR) were significantly lower in the surviving batch (~3-fold) versus the two failed batches. This mismatch for the surviving batch (a high SGR contrasted with low MO₂ and HR), suggested a reduced cost of growth and likely bioenergetic conservation prior to metamorphosis-an energetically demanding process. The subsequent monitoring of the surviving batch through metamorphosis (~30-40 dph), showed a ~ 10-fold increase in AMO₂ and ~ 2-fold increase in thyroid and corticoid hormones. Lastly, a strong negative correlation of HR vs. MO₂ during early development putatively suggested future batch failure.</p>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":" ","pages":"112081"},"PeriodicalIF":2.4,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149229153","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":"Mitochondrial-targeted H₂S delivery elicits broad transcriptional responses in sulfide-adapted fish.","authors":"Kara Ryan, Madison Nobrega, Lenin Arias-Rodriguez, Joanna L Kelley, Michael Tobler","doi":"10.1016/j.cbpa.2026.112080","DOIUrl":"https://doi.org/10.1016/j.cbpa.2026.112080","url":null,"abstract":"<p><p>Hydrogen sulfide (H₂S) is an environmental toxicant that inhibits cellular energy production in mitochondria. Despite its toxicity, multiple lineages of the freshwater fish Poecilia mexicana (Poeciliidae) have independently colonized and adapted to H₂S-rich springs. Prior studies indicated that gene expression responses to H₂S exposure in both adapted and non-adapted populations extend beyond traditional toxicity targets and enzymatic detoxification pathways, suggesting a complex molecular response. Here, we investigated whether mitochondrial H₂S exposure is sufficient to generate broad transcriptional responses. We used a mitochondria-targeted H₂S donor, AP39, to assess transcriptional responses to mitochondrial-targeted H₂S delivery in gill and liver tissues. Despite mitochondrial targeting, we found strong transcriptional responses, especially in the liver, that extended beyond mitochondrial processes and included pathways associated with cellular stress, metabolism, and transcriptional regulation. These findings demonstrate that mitochondrial-targeted H₂S is sufficient to elicit broad transcriptional responses, consistent with mitochondrial perturbation contributing to the complex molecular response to H₂S.</p>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":" ","pages":"112080"},"PeriodicalIF":2.4,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149118854","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":"Expression of concern for 'Influence of serotonin on the action of melatonin in MIH-induced meiotic resumption in the oocytes of carp Catla catla' by Saumen Kumar Maitra, Comp Biochem Physiol A Mol Integr Physiol Volume 150, Issue 3, July 2008, Pages 301-306, 10.1016/j.cbpa.2008.03.014.","authors":"","doi":"10.1016/j.cbpa.2026.112071","DOIUrl":"https://doi.org/10.1016/j.cbpa.2026.112071","url":null,"abstract":"","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":" ","pages":"112071"},"PeriodicalIF":2.4,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149139547","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 sleep-wake patterns of plateau zokors (Eospalax baileyi)","authors":"Xing-Wen Yang ,&nbsp;Hai-Lin Chen ,&nbsp;Pei-Lin Hui ,&nbsp;Jun-Fan Xie ,&nbsp;Yi-Ping Hou ,&nbsp;Yu-Feng Shao","doi":"10.1016/j.cbpa.2026.111984","DOIUrl":"10.1016/j.cbpa.2026.111984","url":null,"abstract":"<div><div>Plateau zokors (<em>Eospalax baileyi</em>), endemic to the Qinghai-Tibet Plateau (QTP), are solitary subterranean rodents that spend their lifespan within underground burrows. Although the activity rhythms of the plateau zokors have been slightly documented, their sleep-wake patterns and seasonal variations remain unclear. Here, we investigated the sleep-wake patterns of wild-caught plateau zokors during spring and autumn using polysomnographic (PSG) recordings in the lab, and compared the findings with those of Sprague-Dawley (SD) rats. We found that plateau zokors exhibit three clearly distinguishable brain states: wakefulness (W), non-rapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep. Under complete darkness in spring, they showed rhythmic-like activity. Compared with daytime periods, they spent significantly more time in wakefulness (398.88 ± 15.02 min <em>vs.</em> 320.55 ± 23.69 min, <em>P</em> &lt; 0.05), and less time both in NREM sleep (257.32 ± 11.28 min <em>vs.</em> 312.23 ± 18.18 min, <em>P</em> &lt; 0.05) and REM sleep (63.80 ± 6.63 min <em>vs.</em> 87.22 ± 7.27 min, <em>P</em> &lt; 0.05) during the nocturnal period (local time). Although the plateau zokors in autumn did not exhibit significant rhythmic-like activity, they showed higher levels of wakefulness in the awake state and shallower sleep during sleep. Notably, plateau zokors had longer and more stable REM sleep compared to SD rats. These findings provide new empirical evidence for adaptive strategies in sleep ecophysiology and help reveal the functions and evolutionary strategies of sleep.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"314 ","pages":"Article 111984"},"PeriodicalIF":2.2,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146159236","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":"Metabolomics investigation of energy metabolism adaptation strategies of liver in female rainbow trout under critical thermal minimum conditions","authors":"Zixuan Zhong,&nbsp;Yujun Kang,&nbsp;Chunmei Zhang,&nbsp;Shuangcheng Chang,&nbsp;Jichang Liu,&nbsp;Yueqing Wang,&nbsp;Jinlian Wu,&nbsp;Jianfu Wang,&nbsp;Jinqiang Huang,&nbsp;Zhe Liu","doi":"10.1016/j.cbpa.2026.111985","DOIUrl":"10.1016/j.cbpa.2026.111985","url":null,"abstract":"<div><div>Temperature is a fundamental environmental determinant in fish physiology. Rainbow trout (<em>Oncorhynchus mykiss</em>), a globally farmed cold-water economic fish and a model in environmental physiology, faces severe acute cold stress during farming and transportation, which threatens its survival and the sustainability of the industry. When exposed to temperatures close to its critical thermal minimum (CT_min), this poses a significant physiological challenge for the species. This study elucidates the systemic hepatic metabolic response of female rainbow trout to acute CT_min stress. We determined the CT_min of the experimental cohort at 0.2 °C through gradient cooling. Non-targeted metabolomics of liver tissue revealed 113 differentially abundant metabolites between the CT_min treatment group (TG, <em>n</em> = 6, 0.2 °C) and control group (CG, n = 6, 12 °C). Statistical filtering (VIP &gt; 1, <em>P</em> &lt; 0.05, FC ≥ 1.5 or ≤ 0.667) identified eight key metabolites—including arginine and phenylalanine—that were significantly enriched in pathways central to amino acid biosynthesis and glycerophospholipid metabolism. Concomitant enzyme activity assays demonstrated that CT_min exposure triggered a coordinated hepatic response characterized by downregulated energy and amino acid metabolism, compromised cell membrane integrity associated with phospholipid dysregulation, and attenuated antioxidant capacity. Our results define a clear metabolic reprogramming in the rainbow trout liver during critical low-temperature stress, providing a mechanistic framework for understanding cold adaptation in teleosts and revealing potential metabolic markers for thermal limit assessment.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"314 ","pages":"Article 111985"},"PeriodicalIF":2.2,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146183618","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":"Is oxidative stress in the brain correlated with plasma markers of oxidative stress?","authors":"Caleb N. Zimmerman ,&nbsp;Ryan Y. Wong ,&nbsp;Peter D. Dijkstra","doi":"10.1016/j.cbpa.2026.111979","DOIUrl":"10.1016/j.cbpa.2026.111979","url":null,"abstract":"<div><div>Oxidative stress in the brain may contribute to the onset and progression of mental health disorders. Markers of oxidative stress in serum or blood plasma have been used to predict cognitive decline or identify subjects at risk of developing neurodegenerative disease. However, plasma markers of oxidative stress are rarely directly linked to patterns of oxidative stress in the brain in the same study. Here, we assessed whether peripheral markers of oxidative stress were positively linked to oxidative stress measurements from several macrodissected brain divisions in a highly social cichlid fish, <em>Astatotilapia burtoni</em>. We generated composite measures of brain oxidative stress marker variation by performing principal component analysis on brain markers including oxidative DNA damage (8-OHdG), total antioxidant capacity (TAC), and glutathione levels measured across four brain divisions in dominant and subordinate males. We found that plasma oxidative damage, measured as derivatives of reactive oxygen metabolites (d-ROMs), was not significantly associated with the first two principal components representing brain oxidative stress marker patterns. The link between plasma total antioxidant capacity and brain oxidative stress patterns (PC1 and PC2) varied between dominant and subordinate individuals, but within these social states there were no significant associations between plasma TAC and brain oxidative stress marker patterns. Our study suggests that plasma markers of oxidative stress are poor predictors of individual oxidative stress levels in specific brain divisions.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"314 ","pages":"Article 111979"},"PeriodicalIF":2.2,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146159291","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":"Time- and dose-dependent effects of bacterial infection on iron metabolism, inflammation, and oxidative stress in the juvenile soft-shelled turtle Pelodiscus sinensis","authors":"Yang Lu,&nbsp;Yu Zhang,&nbsp;Cuijuan Niu","doi":"10.1016/j.cbpa.2026.111977","DOIUrl":"10.1016/j.cbpa.2026.111977","url":null,"abstract":"<div><div>Pathogen-induced high mortality is a severe problem in turtle cultures. Increasing evidence indicates that pathogenic infection may disrupt iron homeostasis, thereby creating a vicious cycle of iron imbalance–inflammation–oxidative stress. However, the effects of infection on iron metabolism and related physiological traits in turtles remain unclear. This study aimed to investigate the response of iron metabolism in juvenile soft-shelled turtles (<em>Pelodiscus sinensis</em>) under acute bacterial challenge and its association with inflammation and oxidative stress. We intraperitoneally injected juvenile <em>P. sinensis</em> (108 ± 2.5 g) with the recently identified pathogen <em>Elizabethkingia anophelis</em> at concentrations of 0, 3.24 × 10⁷, 8.10 × 10⁷, and 1.62 × 10⁸ colony-forming units per millilitre (CFU/mL) in a volume of 0.2 mL. We sampled at 6, 24, and 120 h postinjection to assess the physiological responses to bacterial invasion. The results revealed that haemolysis developed as time progressed and the bacterial dose increased, accompanied by a decrease in plasma iron concentration. Moreover, the expression levels of iron metabolism–related genes in the liver and spleen—<em>hepcidin</em>, <em>transferrin</em>, <em>TFR1</em>, and <em>FTH1</em>—increased, whereas <em>FPN1</em> expression decreased, concurrent with elevated tissue iron levels. Oxidative stress levels and the expression of proinflammatory cytokine genes were positively correlated with tissue iron accumulation. Overall, acute <em>E. anophelis</em> infection disrupts iron homeostasis in <em>P. sinensis</em> in a dose- and time-dependent manner, promotes the redistribution of iron from the circulation to storage tissues, exacerbates tissue inflammatory responses, and reduces antioxidant capacity. These findings indicate that dysregulated iron homeostasis plays a central role in infection-associated tissue injury and that restoring iron balance may aid in the treatment of bacterial infections in <em>P. sinensis</em>.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"314 ","pages":"Article 111977"},"PeriodicalIF":2.2,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146097665","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":"Cold-inducible RNA-binding protein as an indicator for acute hypothermal and salinity stresses in euryhaline milkfish (Chanos chanos)","authors":"Yu-Ting Lin ,&nbsp;Tsung-Han Lee ,&nbsp;Liang-Chun Wang ,&nbsp;Chuan-Mu Chen","doi":"10.1016/j.cbpa.2026.111978","DOIUrl":"10.1016/j.cbpa.2026.111978","url":null,"abstract":"<div><div>Climate change increases fluctuations in water salinity and temperature, which affects osmoregulation, energy metabolism, and the immune response in milkfish (<em>Chanos chanos</em>). Milkfish, an important economic species in Southeast Asia, can tolerate a wide range of salinity levels. However, sudden winter cold snaps often result in high mortality among cultured milkfish. Cold-inducible RNA-binding protein (Cirp), a well-known multi-stress indicator in mammals, is inducible by environmental stressors. However, studies on Cirp in teleost fish remain scarce, and most existing work has focused primarily on transcriptomic analyses. This study aimed to assess Cirp expression as a potential indicator of acute environmental stress in milkfish. Two <em>cirp</em> genes, <em>cirpa</em> and <em>cirpb</em>, were previously identified in milkfish; and both are widely distributed among tissues; notably, <em>cirpa</em> expression in the gills is approximately 3-fold higher in fresh water (FW)- than in seawater (SW)-acclimated milkfish. Quantitative real-time PCR revealed that <em>cirpa</em> expression in the gills was upregulated approximately 2-fold, while <em>cirpb</em> expression increased more than 2-fold in the liver and gills of milkfish at 24 h of hypothermal stress across salinity conditions. Furthermore, <em>cirpb</em> expression in the gills increased (approximately 1.8-fold) at 12 and 24 h after exposure to a hyperosmotic challenge and at 6 h after transferring to a hypoosmotic environment, whereas <em>cirpa</em> expression was induced about 2-fold only after hypothermal challenge at 12 h. Overall, <em>cirpb</em> expression was consistently upregulated by both salinity and hypothermal stress in the gills and liver of milkfish, whereas <em>cirpa</em> showed a more limited response, indicating that <em>cirpb</em> is a more sensitive molecular indicator of hypothermal and osmotic stress.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"314 ","pages":"Article 111978"},"PeriodicalIF":2.2,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146133658","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":"Thermal adaptation strategies in congeneric lizards: Cold tolerance in high-altitude Phrynocephalus erythrurus and overheat-avoidance in low-altitude P. przewalskii","authors":"Shengkang Men ,&nbsp;Yonggang Niu ,&nbsp;Xuejing Zhang ,&nbsp;Yuxia Feng ,&nbsp;Xiangtao Li ,&nbsp;Yucheng Bai ,&nbsp;Huihui Wang ,&nbsp;Xiaolong Tang ,&nbsp;Qiang Chen","doi":"10.1016/j.cbpa.2026.111981","DOIUrl":"10.1016/j.cbpa.2026.111981","url":null,"abstract":"<div><div>Altitudinal gradients drive divergent thermal adaptations in ectotherms, but the integrated behavioral-physiological mechanisms underlying such specialization remain unclear. We tested adaptive strategies in two congeneric lizards: high-altitude <em>Phrynocephalus erythrurus</em> (4500–5300 m) and low-altitude desert-dwelling <em>P. przewalskii</em> (1000–1700 m). Hypothesizing cold tolerance in the former and heat avoidance in the latter, we combined field thermal profiling and laboratory assays to quantify key thermal traits. Results showed <em>P. erythrurus</em> occupies a colder habitat with shorter activity windows, exhibiting a lower critical thermal minimum (CTₘᵢₙ = −0.20 ± 0.58 °C) and upper escape temperature (UETₐ) for cold adaptation. <em>P. przewalskii</em> displayed a larger high-temperature thermal safety margin (TSMwarm = 4.40 °C) and greater ambient-body temperature difference at escape (ΔUET), reflecting specialized heat avoidance. Behaviorally, <em>P. erythrurus</em> relied on microhabitat selection for precise thermoregulation, while <em>P. przewalskii</em> used frequent shuttling. Both warmed faster than cooled, with a novel finding of heart rate hysteresis—cardiovascular performance depends on thermal change sequence, not absolute temperature. This study reveals divergent evolutionary pathways (cold endurance vs. heat avoidance) shaped by altitude, providing a mechanistic framework for predicting species-specific vulnerabilities to climate change. Our findings advance understanding of ectotherm adaptive radiation and inform conservation strategies amid global warming, highlighting that low-altitude species face imminent thermal safety margin compression while high-altitude specialists confront unprecedented heat extremes.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"314 ","pages":"Article 111981"},"PeriodicalIF":2.2,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146159251","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}