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

{"title":"Does cooling affect skeletal muscle glycogen replenishment after an acute bout of fear-induced exertional hyperthermia in blesbok (Damaliscus pygargus phillipsi)?","authors":"Tertius A. Kohn ,&nbsp;Mahmooda Martin ,&nbsp;Kathryn M. van Boom ,&nbsp;Byron Donaldson ,&nbsp;Dee M. Blackhurst ,&nbsp;Agustina Fitte ,&nbsp;Richard Burroughs ,&nbsp;Johan C.A. Steyl ,&nbsp;Amelia Goddard ,&nbsp;Leith C.R. Meyer","doi":"10.1016/j.cbpa.2025.111921","DOIUrl":"10.1016/j.cbpa.2025.111921","url":null,"abstract":"<div><div>Rhabdomyolyses is a clinical sign of capture myopathy in wild animals and may be linked to glycogen metabolism. To study potential mechanisms, 26 wild blesbok were chased for 15 min and immobilised, whereafter 12 of these blesbok were doused with ice-water (<em>n</em> = 14 chased only group; <em>n</em> = 12 chased + cooled group). An additional 12 blesbok served as resting (not chased) uncooled controls. <em>Vastus lateralis</em> biopsies were obtained after immobilisation for biochemical analyses. Biopsies obtained at initial capture, 3- and 16-days post exercise were analysed for glycogen content. Blesbok muscles contained predominantly myosin heavy chain (MHC) IIA (∼50 ± 9 %), followed by IIX (32 ± 10 %) and MHC I (18 ± 5 %), with no difference between groups. Citrate synthase (mean: 87 ± 48), 3-hydroxyacetyl co A dehydrogenase (47 ± 17), lactate dehydrogenase (1567 ± 654), phosphorylase (162 ± 94), phosphofructokinase (250 ± 123) and creatine kinase (12,455 ± 6372) activities (in μmol/min/g prot) were not different between groups. Similarly, superoxide dismutase (7.9 ± 7 U/mg prot), catalase (8.8 ± 5.8 mmol/min/g prot), and overall antioxidant capacity (ORAC: 23055 ± 18,460 μmol/g prot) were not different between groups. Glycogen content was reduced in both chased groups and not replenished by day 3. Glycogen supercompensation was observed on day 16 in both chased groups (∼33 % higher than resting control group). The results confirm that blesbok have high muscle metabolic capacities, and that glycogen resynthesis is slow, which could lead to metabolite deficiency during prolonged chase events (&gt;15 min).</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"309 ","pages":"Article 111921"},"PeriodicalIF":2.2,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144857098","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 expression of ferroptosis-related genes and oxidative stress level between chicken breast and thigh muscles","authors":"Tomonori Nakanishi ,&nbsp;Jun Wakamatsu ,&nbsp;Saki Nemoto ,&nbsp;Akihiro Yamamoto ,&nbsp;Laurie Erickson ,&nbsp;Satoshi Kawahara","doi":"10.1016/j.cbpa.2025.111919","DOIUrl":"10.1016/j.cbpa.2025.111919","url":null,"abstract":"<div><div>Ferroptosis is an iron-dependent regulated cell death characterized by lipid peroxidation. In the skeletal muscle of mammals, where oxidative stress plays an important role in lipid peroxidation, ferroptosis is involved in various diseases and aging. However, the role of ferroptosis in avian skeletal muscle remains underexplored. This study investigated the gene expression of glutathione peroxidase 4 (<em>GPX4</em>) and other ferroptosis-related genes, along with oxidative stress markers in chicken skeletal muscles, focusing on the breast (pectoralis major) and thigh (iliotibialis lateralis) muscles. Gene expression was analyzed using quantitative reverse transcription polymerase chain reaction. Lipid peroxidation and oxidative stress were evaluated by measuring malondialdehyde (MDA), a lipid peroxidation byproduct, and by evaluating the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG). Our results showed that <em>GPX4</em> gene expression was significantly higher in the thigh muscle compared to the breast muscle. Ferroptosis suppressor protein 1 (<em>FSP1</em>) expression was also higher in the thigh muscle, while ferritin heavy chain 1 (<em>FTH1</em>) expression was lower in the thigh muscle than in the breast muscle. In contrast, lipid peroxidation, indicated by MDA levels, was higher in the breast muscle, correlating with a lower GSH/GSSG ratio, indicating that the breast muscle is more susceptible to ferroptosis than the thigh muscle. Additionally, the expression of <em>FSP1</em> and <em>FTH1</em> showed significant correlations with oxidative stress markers, highlighting their roles in regulating ferroptosis in avian skeletal muscle. This study provides insights into the molecular mechanisms of ferroptosis in avian skeletal muscle, suggesting that regulatory processes may vary between muscle types.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"309 ","pages":"Article 111919"},"PeriodicalIF":2.2,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144857097","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":"Comparison of redox metabolism during hibernation in the apple snail Pomacea canaliculata under natural and laboratory-controlled conditions","authors":"Maximiliano Giraud-Billoud ,&nbsp;Marcelo Hermes-Lima","doi":"10.1016/j.cbpa.2025.111918","DOIUrl":"10.1016/j.cbpa.2025.111918","url":null,"abstract":"<div><div>Preparation for oxidative stress (POS) is an adaptive strategy for tolerating adverse environmental conditions. It has been demonstrated in over one hundred animals, but the vast majority of the work was done under controlled-laboratory conditions and not in nature. There are no studies evaluating this strategy in the same species comparing laboratory and natural conditions. This study aimed to determine whether POS happens in <em>Pomacea canaliculata</em> snails both in the laboratory (controls versus 7-day hibernation) and in animals collected in the wild (summer versus cold-winter hibernation). The activity of antioxidant enzymes, antioxidant capacity (ABTS), lipid peroxidation levels (TBARS), uric acid, and expression of redox-sensitive transcription factors were determined in foot muscle. Hibernating wild-snails presented increased TBARS compared to summer ones, as well as the activities of SOD and catalase and levels of uric acid; ABTS decreased in winter animals. In laboratory conditions, hibernating snails also exhibited increased TBARS, catalase and glutathione S-transferase and a decrease in ABTS levels. Gene expression of Nrf2 increased in laboratory-hibernation whereas HIF-1α decreased in field-hibernation. Our study shows for the first time that the POS phenotype is similar in lab and wild conditions—hibernating snails exhibit higher lipid peroxidation and antioxidant protection in both.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"309 ","pages":"Article 111918"},"PeriodicalIF":2.2,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144828868","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":"An energetic conundrum: contradictory relationship between energetic state and heat tolerance during progressive air exposure in a tropical high-shore gastropod","authors":"M Akram Ullah ,&nbsp;Cristián J. Monaco ,&nbsp;David J. Marshall","doi":"10.1016/j.cbpa.2025.111917","DOIUrl":"10.1016/j.cbpa.2025.111917","url":null,"abstract":"<div><div>High-shore intertidal gastropods experience energy-demanding thermo-dehydrative stressful conditions during air emersion, related to their vertical position and the habitat heterogeneity. Simultaneously, these gastropods are forced to downregulate metabolism when resting in air to limit dehydration and ensure energetic homeostasis under conditions of constrained food (energy) intake, due to prolonged inactivity. We investigated this apparent conundrum by studying the temporal patterning of metabolic depression and the influence of depressed metabolism on heat tolerance of the tropical high-shore snail, <em>Planaxis sulcatus,</em> during progressive air emersion. We compared cardiac thermal performance (a proxy for metabolic performance) of snails pre-exposed to different periods of air emersion (field fresh, 5 d and 10 d) and different levels of dehydration and heat stress, mimicking naturally sunned or shaded resting habitats. Compared to early air emersion, long resting periods under benign (shaded) conditions suppressed cardiac thermal performance and elevated heat tolerance, responses mostly not modified by dehydration or heat stress. Cardiac (energetic) suppression was temporally idiosyncratic among individuals, becoming more uniform with longer air emersion. Reanalyzed data comparing higher and lower metabolic (energetic) states across the treatments showed greater heat tolerance in lower-energetic snails. The apparent energetic conundrum of simultaneously needing to support energetically-demanding protective heat tolerance and energetically-conserving metabolic depression can be explained by an early highly energy-demanding preparatory stage, which hardens snails for the duration of aestivation, irrespective of the resting habitat conditions. Our observed temporal patterning of metabolism provides an excellent framework for molecular and cellular investigation of high-shore snails.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"309 ","pages":"Article 111917"},"PeriodicalIF":2.2,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144849694","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":"Group size influences feeding behavior and the expression of appetite, stress, and neurotransmitter-related transcript expression in tiger barb (Puntigrus tetrazona)","authors":"Julianne M.D. King,&nbsp;Helene Volkoff","doi":"10.1016/j.cbpa.2025.111915","DOIUrl":"10.1016/j.cbpa.2025.111915","url":null,"abstract":"<div><div>Tiger barbs (<em>Puntigrus tetrazona)</em> are typical shoaling fish that can become stressed and aggressive when kept in small groups. To examine whether group size affects feeding, fish were housed in groups of 1, 2, 4, or 8 individuals per tank and monitored over a 10-day period. Overall feeding behavior, latency to feed, and the amount of food consumed were assessed daily. After 10 days under these conditions, fish were sampled for intestine and brain for transcript expression analyses. Genes examined included appetite regulators such as neuropeptide Y-<em>npy</em>, <em>orexin</em> and melanin-concentrating hormone-<em>mch</em> in the brain and cholecystokinin-<em>cck</em> and <em>ghrelin</em> in the intestine. We also analyzed brain expression of hormones related to social behavior and stress (oxytocin-<em>oxt</em>, corticotrophin-releasing factor-<em>crf</em> and thyrotropin-releasing hormone-<em>trh</em>) and genes related to the synthesis of serotonin (tryptophan hydroxylase-<em>tph</em>) and dopamine (tyrosine hydroxylase-<em>th</em>) and epinephrine (dopamine-β-hydroxylase- <em>dbh</em>). Isolated fish consumed significantly less food and exhibited longer latency to feed compared to all other groups. Fish housed in pairs also showed reduced intake and longer feeding latency relative to those in groups of 4. In the intestine, <em>ghrelin</em> expression was elevated in isolated fish relative to those in larger groups, while no differences were observed in <em>ccka</em> or <em>cckb</em> expression. In the brain, expression of orexigenic neuropeptides (<em>npy</em>, <em>mch</em>, and <em>orexin</em>) was higher in isolated and pair-housed fish compared to those in groups of 4 or 8. Expression of stress- and neurotransmitter-related genes (<em>crf</em>, <em>trh</em>, <em>th</em>, and <em>tph1</em>) was also significantly elevated in isolated fish. No significant group-size effects were found for <em>oxt</em>, <em>tph2</em>, <em>dbh</em>, or <em>cart</em> expression. Overall, our results suggest that small group sizes, particularly isolation, impair feeding behavior and upregulate orexigenic and stress-related gene expression, highlighting the importance of social environment in regulating physiological and behavioral responses in shoaling fish.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111915"},"PeriodicalIF":2.2,"publicationDate":"2025-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144763739","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":"Identification and functional characterization of a novel ovarian-specific Kelch domain-containing gene involved in the ecdysteroid signaling pathway of Penaeus monodon","authors":"Jakkapong Kluebsoongnoen ,&nbsp;Duangrudee Tanramluk ,&nbsp;Maryam Jozghorbani ,&nbsp;Jutarop Phetcharaburanin ,&nbsp;Tomasz J. Sarnowski ,&nbsp;Apinunt Udomkit","doi":"10.1016/j.cbpa.2025.111914","DOIUrl":"10.1016/j.cbpa.2025.111914","url":null,"abstract":"<div><div>In crustaceans, vitellogenin (Vg) synthesis is regulated by complex hormonal and molecular networks. This study investigates the role of the ecdysone receptor (PmEcR) in regulating <em>Vg</em> expression and identifies downstream effectors in <em>Penaeus monodon</em>. Silencing of <em>PmEcR</em> using RNA interference resulted in a two-fold increase in <em>Vg</em> expression and a significant rise in the gonadosomatic index (GSI), suggesting <em>PmEcR</em> acts as a suppressor of vitellogenesis.</div><div>Through a suppression subtractive hybridization (SSH) technique, an uncharacterized <em>LOC 113805388</em> gene, was identified as being downregulated upon <em>PmEcR</em> silencing. Functional and structural characterization revealed this transcript as an ovarian-specific protein with a β-propeller structure (Kelch-like domain-containing protein; PmKel), suggesting that it belongs to a Kelch-like protein family generally involved in protein-protein interactions in cellular regulation. LC-MS/MS analysis of the ovarian proteome confirmed the presence of the PmKel protein, verifying its expression in the ovary. <em>PmKel</em> expression displayed an inverse pattern to that of <em>Vg</em> during ovarian development, and its knockdown was associated with increased <em>Vg</em> transcript levels, suggesting a possible role in the regulation of <em>Vg</em> gene expression. In addition, a recombinant PmKel protein was produced and used as a bait to identify its partners in ovarian nuclear extract by affinity purification mass spectrometry (AP-MS). The isolated set of interacting proteins highlighted functional enrichment in mRNA and protein metabolic processes involved in developmental pathways. Also, these proteins could interact with a Kelch-like domain predicted on PmKel 3D protein structure by protein network analysis and protein-protein docking. These findings suggest that PmKel is a novel ovarian specific Kelch-containing protein that plays a key role in the vitellogenesis regulatory network via the EcR pathway. Collectively, these results add to the current knowledge of shrimp reproduction and may suggest future direction for improving reproductive performance in aquaculture.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111914"},"PeriodicalIF":2.2,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144769383","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":"Assessing metabolite profiles of wild Swainson's thrushes (Catharus ustulatus) in different moult stages using a veterinary point of care device","authors":"Elena Tranze-Drabinia ,&nbsp;Vanessa Poirier ,&nbsp;Barbara Frei ,&nbsp;Kyle H. Elliott","doi":"10.1016/j.cbpa.2025.111912","DOIUrl":"10.1016/j.cbpa.2025.111912","url":null,"abstract":"<div><div>Migration and moult are both energetically demanding and have conflicting physiological requirements, therefore usually separated in time. In some species, individuals may interrupt their migration to moult at discrete stopover locations outside of their breeding grounds (i.e., moult-migration) leading to competing physiological demands for moult and migration as protein is needed both for feather regeneration and efficient migration. Here, we examine the plasma metabolite profiles between moulting and post-moulting migrants by using a point-of-care analyzer providing real-time data in the field. Post-moulting birds, who were on shorter migration stopovers, had significantly higher concentrations of aspartate aminotransferase, calcium, sodium, phosphorous, and total protein than moulting birds, which is consistent with higher metabolic demands during migration and depletion of protein due to feather regeneration during moult. Additionally, uric acid, creatine kinase, total protein, aspartate aminotransferase, and potassium – all indicative of protein catabolism, muscle damage, and dehydration – were higher in lighter birds (below a scaled mass index of 7–7.5) regardless of moult status, which is consistent with lower energy reserves reflecting nutritional stress. Together, these metabolite profiles, measured in situ at a banding station, provide real-time insight into how birds mitigate the physiologically competing demands of moult and migration at a peri-urban stopover.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111912"},"PeriodicalIF":2.2,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144755173","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":"Bim gene regulation in hypoxic stress response of blunt snout bream (Megalobrama amblycephala): Mechanisms of apoptosis, oxidative stress, and transcriptional control by c-Ets-2","authors":"Siyu Ding ,&nbsp;Yahui Feng ,&nbsp;Loic Kemmadzong Foning ,&nbsp;Jie Chen ,&nbsp;Guodong Zheng ,&nbsp;Shuming Zou","doi":"10.1016/j.cbpa.2025.111913","DOIUrl":"10.1016/j.cbpa.2025.111913","url":null,"abstract":"<div><div>Despite its significant economic value, the blunt snout bream (<em>Megalobrama amblycephala</em>) is extremely sensitive to hypoxia. Derived from blunt snout bream gill filament cell lines, <em>Megalobrama amblycephala</em> gill (MAG) cells are closely linked to hypoxia, making them suitable for identifying related genes' hypoxia tolerance. This study explores the roles of the <em>Bcl-2</em> interacting mediator of cell death gene (<em>Bim</em>) in the gill tissues and MAG cells under hypoxic conditions. <em>Bim</em> expression increased significantly (<em>P</em> &lt; 0.05) after 24 h of hypoxia but decreased following reoxygenation. Overexpression of <em>Bim</em> significantly (P &lt; 0.05) upregulated the expression of pro-apoptotic genes <em>Bax</em> and <em>Caspase 3</em>, while downregulating the expression of the anti-apoptotic gene <em>Bcl-2</em>. Conversely, <em>Bim</em> interference exhibited an opposite trend. Hypoxia led to increased apoptosis and decreased mitochondrial membrane potential (MMP) in MAG cells, which was exacerbated by overexpression of <em>Bim</em>. In contrast, <em>Bim</em> interference attenuated apoptosis and prevented the decrease in MMP. ROS levels significantly (<em>P</em> &lt; 0.05) increased under hypoxic conditions, and <em>Bim</em> overexpression further elevated ROS production, whereas <em>Bim</em> interference reduced ROS levels. Antioxidant enzyme (SOD, CAT) activity decreased after hypoxia, which was exacerbated by <em>Bim</em> overexpression, while <em>Bim</em> interference slowed the decline of enzyme activity. The dual-luciferase reporter assay confirmed that the transcription factor c-Ets-2 regulates the expression of <em>Bim</em> by binding to the -GAGGAA site of the <em>Bim</em> promoter. This study highlights <em>Bim</em>'s key role in hypoxic stress and offers new insights into the hypoxic adaptation mechanisms of blunt snout bream.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111913"},"PeriodicalIF":2.2,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144755186","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":"Short communication: Elevated testosterone correlates with enhanced innate immune function in a cooperatively breeding rodent","authors":"K.M.E. Wallace ,&nbsp;S.N. Venter ,&nbsp;N.C. Bennett ,&nbsp;D.W. Hart","doi":"10.1016/j.cbpa.2025.111911","DOIUrl":"10.1016/j.cbpa.2025.111911","url":null,"abstract":"<div><div>In many vertebrates, elevated testosterone is believed to compromise the immune function, reflecting a trade-off between reproduction and survival. However, such trade-offs may potentially be relaxed in cooperative breeders, where social conflict and sexual selection are reduced. We investigated the relationship between testosterone, cortisol, and innate immunity in captive male Damaraland mole-rats (<em>Fukomys damarensis</em>), a eusocial rodent with minimal aggression-driven reproductive competition. Using microbial killing assays (MKAs) and white blood cell counts as proxies of immune function, we found that urinary testosterone concentration was positively correlated with immune strength. Males with higher urinary testosterone concentrations exhibited significantly greater antimicrobial capacity and elevated total white blood cell counts. However, urinary testosterone was unrelated to independent immune cell differentials. While, reproductive status, age, body mass, and urinary cortisol concentrations had a limited effect on any immune metric. These findings, while correlative, challenge traditional endocrine-immune trade-off models and infer that, in this species, testosterone may signal condition rather than impose immunosuppressive costs.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111911"},"PeriodicalIF":2.2,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739300","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 development and plasticity of acid excretion mechanisms in early life stage red drum, Sciaenops ocellatus","authors":"Joshua Lonthair ,&nbsp;Andrew J. Esbaugh","doi":"10.1016/j.cbpa.2025.111910","DOIUrl":"10.1016/j.cbpa.2025.111910","url":null,"abstract":"<div><div>Ocean acidification (OA) has been shown to affect early life stage fishes in a variety of ways, including reduced survival and growth, and increased tissue damage. Yet, there is also substantial interspecies variability in the sensitivity of early life stage fishes to high CO₂, and it has been theorized that this may relate to the ontogeny of systemic acid-base regulatory pathways; an area that has been surprisingly understudied in obligate marine species. Here, we used an integrative set of approaches to describe the development and plasticity of acid excretion pathways in developing red drum (<em>Sciaenops ocellatus</em>), a marine fish native to the Gulf of Mexico. We observed mRNA expression of relevant transporters and ionocytes immediately post-hatch (36 h post-fertilization, hpf) with relatively stable abundance throughout the pre-metamorphic stages. Consistent with work in adults and seawater acclimated euryhaline larvae, we demonstrate strong co-localization of acid excretion proteins within a single epithelial ionocyte cell-type. Measurements of epithelial Δ[H]⁺, an indicator of proton efflux, showed that by 72 hpf larvae had CO₂-responsive EIPA-sensitive acid excretion, confirming the presence of sodium proton exchanger (NHE)-mediated acid excretion. Elevated mRNA expression of <em>nhe2</em> and <em>nhe3</em> was induced following exposure to 5500 and 12,000 μatm CO₂, which coincided with the absence of further survival effects relative to lower dose CO₂. Overall, these data confirm that red drum have fully functional epithelial acid excretion pathways in early life, and that plasticity in these pathways may offer survival benefits.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111910"},"PeriodicalIF":2.2,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144735493","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}