Pub Date : 2025-07-28DOI: 10.1016/j.cbpa.2025.111913
Siyu Ding , Yahui Feng , Loic Kemmadzong Foning , Jie Chen , Guodong Zheng , Shuming Zou
Despite its significant economic value, the blunt snout bream (Megalobrama amblycephala) is extremely sensitive to hypoxia. Derived from blunt snout bream gill filament cell lines, Megalobrama amblycephala gill (MAG) cells are closely linked to hypoxia, making them suitable for identifying related genes' hypoxia tolerance. This study explores the roles of the Bcl-2 interacting mediator of cell death gene (Bim) in the gill tissues and MAG cells under hypoxic conditions. Bim expression increased significantly (P < 0.05) after 24 h of hypoxia but decreased following reoxygenation. Overexpression of Bim significantly (P < 0.05) upregulated the expression of pro-apoptotic genes Bax and Caspase 3, while downregulating the expression of the anti-apoptotic gene Bcl-2. Conversely, Bim 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 Bim. In contrast, Bim interference attenuated apoptosis and prevented the decrease in MMP. ROS levels significantly (P < 0.05) increased under hypoxic conditions, and Bim overexpression further elevated ROS production, whereas Bim interference reduced ROS levels. Antioxidant enzyme (SOD, CAT) activity decreased after hypoxia, which was exacerbated by Bim overexpression, while Bim interference slowed the decline of enzyme activity. The dual-luciferase reporter assay confirmed that the transcription factor c-Ets-2 regulates the expression of Bim by binding to the -GAGGAA site of the Bim promoter. This study highlights Bim's key role in hypoxic stress and offers new insights into the hypoxic adaptation mechanisms of blunt snout bream.
{"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 , Yahui Feng , Loic Kemmadzong Foning , Jie Chen , Guodong Zheng , 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> < 0.05) after 24 h of hypoxia but decreased following reoxygenation. Overexpression of <em>Bim</em> significantly (P < 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> < 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}
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 (Fukomys damarensis), 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.
{"title":"Short communication: Elevated testosterone correlates with enhanced innate immune function in a cooperatively breeding rodent","authors":"K.M.E. Wallace , S.N. Venter , N.C. Bennett , 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}
Pub Date : 2025-07-26DOI: 10.1016/j.cbpa.2025.111910
Joshua Lonthair , Andrew J. Esbaugh
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 (Sciaenops ocellatus), 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 nhe2 and nhe3 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.
{"title":"The development and plasticity of acid excretion mechanisms in early life stage red drum, Sciaenops ocellatus","authors":"Joshua Lonthair , 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 CO<sub>2</sub>, 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]<sup>+</sup>, an indicator of proton efflux, showed that by 72 hpf larvae had CO<sub>2</sub>-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 CO<sub>2</sub>, which coincided with the absence of further survival effects relative to lower dose CO<sub>2</sub>. 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}
Pub Date : 2025-07-26DOI: 10.1016/j.cbpa.2025.111909
Julia Cacace , Guido Fernández Marinone , Fabricio Damián Cid , Juan Gabriel Chediack
Heatwaves and warm spells occurring worldwide as a result of climate change disrupt the homeostasis of animals, leading to heat stress. Consequently, animals must respond to these alterations in order to ensure their survival. The response involves several physiological changes, such as releasing of glucocorticoids and catecholamines, to restore homeostasis. Due to the lack of knowledge on this subject in wild birds, the objective of the present work was to study the effect of heat stress on body condition and digestive system in house sparrows (Passer domesticus). In addition, since capsaicin is used as additive in poultry to mitigate heat stress and it is a common additive in seeds for house birdfeeders to prevent squirrels from eating their food, the second objective of this study was a possible role of capsaicin as a dietary additive in mitigating heat stress and to check the effect of capsaicin in digestive system. In this work, we measured heterophil/lymphocytes ratio (H/L ratio) as a proxy of stress; body mass, hematocrit, uric acid and digestive enzymes (intestinal and pancreatic) under stress conditions at 32 ± 2 °C and under normal conditions at 22 ± 2 °C. In addition, we evaluated the effect of capsaicin in both situations (heat stress at 32 °C and normal condition 22 °C). We found an increase of H/L ratio under heat stress, and decrease of H/L ratio with capsaicin on animals exposed to heat stress. Although a loss of intestinal mass was observed in animals exposed at 32 °C, digestive enzyme activity does not change under heat stress or under capsaicin administration. Improving knowledge in this field is relevant at the level of animal nutrition and veterinary medicine, while also bearing relevance for wild birds, where it becomes crucial to explore potential mitigation strategies for future global warming scenarios.
{"title":"Impacts of heat stress and its mitigation by capsaicin in health status and digestive enzymes in house sparrows (Passer domesticus)","authors":"Julia Cacace , Guido Fernández Marinone , Fabricio Damián Cid , Juan Gabriel Chediack","doi":"10.1016/j.cbpa.2025.111909","DOIUrl":"10.1016/j.cbpa.2025.111909","url":null,"abstract":"<div><div>Heatwaves and warm spells occurring worldwide as a result of climate change disrupt the homeostasis of animals, leading to heat stress. Consequently, animals must respond to these alterations in order to ensure their survival. The response involves several physiological changes, such as releasing of glucocorticoids and catecholamines, to restore homeostasis. Due to the lack of knowledge on this subject in wild birds, the objective of the present work was to study the effect of heat stress on body condition and digestive system in house sparrows (<em>Passer domesticus</em>). In addition, since capsaicin is used as additive in poultry to mitigate heat stress and it is a common additive in seeds for house birdfeeders to prevent squirrels from eating their food, the second objective of this study was a possible role of capsaicin as a dietary additive in mitigating heat stress and to check the effect of capsaicin in digestive system. In this work, we measured heterophil/lymphocytes ratio (H/L ratio) as a proxy of stress; body mass, hematocrit, uric acid and digestive enzymes (intestinal and pancreatic) under stress conditions at 32 ± 2 °C and under normal conditions at 22 ± 2 °C. In addition, we evaluated the effect of capsaicin in both situations (heat stress at 32 °C and normal condition 22 °C). We found an increase of H/L ratio under heat stress, and decrease of H/L ratio with capsaicin on animals exposed to heat stress. Although a loss of intestinal mass was observed in animals exposed at 32 °C, digestive enzyme activity does not change under heat stress or under capsaicin administration. Improving knowledge in this field is relevant at the level of animal nutrition and veterinary medicine, while also bearing relevance for wild birds, where it becomes crucial to explore potential mitigation strategies for future global warming scenarios.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111909"},"PeriodicalIF":2.2,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144725137","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}
Pub Date : 2025-07-25DOI: 10.1016/j.cbpa.2025.111908
Jun-Hwan Byun , Seung-Ju Oh , Yeo-Reum Kim , Chae-Eun Yu , Jihun Kim , Hyo-Jeong Kim , Minjae Kim , Byeong-Hoon Kim , Sung-Pyo Hur , Jong-Myoung Kim
Fish inhabiting diverse photic environments, from the deep sea to shallow freshwater, offer a valuable model for studying visual receptor characteristics and spectral adaptation mechanisms. This study investigated changes in visual opsin transcript levels in Japanese eels (Anguilla japonica) during sexual development and exposure to light conditions simulating their life cycle. Tissue-specific expression analysis revealed the predominance of four opsin genes (dso, fwo, rh2, and sws2) in the eyes. Sexual maturation using human chorionic gonadotropin was confirmed by increased gonadosomatic index values and histological changes in the testis. Upon confirming dynamic day/night shifts in the retinal pigment epithelium layer, the effects of sexual maturation and light on opsin gene expression were analyzed via exposure to light-emitting diodes of different wavelengths. Immature eels showed increased sws2 expression under blue and green light during the day, with dominant dso, fwo, rh2, and sws2 expression in darkness and green light during the night. Conversely, mature eels showed elevated expression levels of dso and rh2 under white light and dark conditions, implicating their broad-spectrum and blue-shifted adaptation to deep-sea migration. Notably, cortisol levels in sexually mature eels were significantly lower under dark conditions, underscoring the ecological significance of low light during reproductive migration. Overall, these findings highlight the developmental plasticity of opsin expression and stress responses driven by ecological requirements and life cycle changes, enhancing our understanding of visual and physiological adaptations in migratory fish and providing insights into the evolutionary mechanisms shaping aquatic sensory systems.
{"title":"Analysis of visual opsin gene expression in Japanese eels upon sexual maturation and exposure to different wavelengths of light","authors":"Jun-Hwan Byun , Seung-Ju Oh , Yeo-Reum Kim , Chae-Eun Yu , Jihun Kim , Hyo-Jeong Kim , Minjae Kim , Byeong-Hoon Kim , Sung-Pyo Hur , Jong-Myoung Kim","doi":"10.1016/j.cbpa.2025.111908","DOIUrl":"10.1016/j.cbpa.2025.111908","url":null,"abstract":"<div><div>Fish inhabiting diverse photic environments, from the deep sea to shallow freshwater, offer a valuable model for studying visual receptor characteristics and spectral adaptation mechanisms. This study investigated changes in visual opsin transcript levels in Japanese eels (<em>Anguilla japonica</em>) during sexual development and exposure to light conditions simulating their life cycle. Tissue-specific expression analysis revealed the predominance of four opsin genes (<em>dso</em>, <em>fwo</em>, <em>rh2</em>, and <em>sws2</em>) in the eyes. Sexual maturation using human chorionic gonadotropin was confirmed by increased gonadosomatic index values and histological changes in the testis. Upon confirming dynamic day/night shifts in the retinal pigment epithelium layer, the effects of sexual maturation and light on opsin gene expression were analyzed via exposure to light-emitting diodes of different wavelengths. Immature eels showed increased <em>sws2</em> expression under blue and green light during the day, with dominant <em>dso</em>, <em>fwo</em>, <em>rh2</em>, and <em>sws2</em> expression in darkness and green light during the night. Conversely, mature eels showed elevated expression levels of <em>dso</em> and <em>rh2</em> under white light and dark conditions, implicating their broad-spectrum and blue-shifted adaptation to deep-sea migration. Notably, cortisol levels in sexually mature eels were significantly lower under dark conditions, underscoring the ecological significance of low light during reproductive migration. Overall, these findings highlight the developmental plasticity of opsin expression and stress responses driven by ecological requirements and life cycle changes, enhancing our understanding of visual and physiological adaptations in migratory fish and providing insights into the evolutionary mechanisms shaping aquatic sensory systems.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111908"},"PeriodicalIF":2.2,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144720915","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}
Pub Date : 2025-07-16DOI: 10.1016/j.cbpa.2025.111907
Marie Koch , Sylke Wohlrab , Reinhard Saborowski
The digestive system of sea urchins is well-described, but the biochemical properties of the individual organs are only insufficiently characterized. The digestive tract begins in the buccal cavity, surrounded by a biting apparatus called Aristoteles' lantern. It then forms a tubular structure, which runs two times around the body wall, ending at the aboral side of the animal. This main part of the digestive tube has been described histologically as the stomach (first loop, anticlockwise) and the intestine (second loop, clockwise). We characterized the enzymatic profile as well as the microbial composition of the stomach and the intestine of the green sea urchin Strongylocentrotus droebachiensis, an ecological and economical important arctic-boreal grazer. Using qualitative and quantitative enzyme activity assays on tissue of the stomach and intestine, we identified differences in the biochemical processes, primarily concerning the protein and lipid metabolism. The stomach expressed higher esterase and esterase/lipase activity, while the intestine showed predominantly high exopeptidase activity. Low carbohydrate degrading enzyme activity suggests that polysaccharide digestion, despite their abundance in the species' diet, may primarily occur extracellularly in the lumen of the digestive tube. Our enzymatic findings are complimented by metabarcoding of the microbial community and analysis of functional properties: We found microbial taxa possibly associated with nitrogen fixation and carbohydrate degradation. Nevertheless, the composition and potential functional genes of the microbial community were similar between the two organs, suggesting that they do not play an organ-specific role in digestive processes.
{"title":"Functional enzymatic characterisation and microbiome analysis of the digestive tract of the green sea urchin Strongylocentrotus droebachiensis","authors":"Marie Koch , Sylke Wohlrab , Reinhard Saborowski","doi":"10.1016/j.cbpa.2025.111907","DOIUrl":"10.1016/j.cbpa.2025.111907","url":null,"abstract":"<div><div>The digestive system of sea urchins is well-described, but the biochemical properties of the individual organs are only insufficiently characterized. The digestive tract begins in the buccal cavity, surrounded by a biting apparatus called Aristoteles' lantern. It then forms a tubular structure, which runs two times around the body wall, ending at the aboral side of the animal. This main part of the digestive tube has been described histologically as the stomach (first loop, anticlockwise) and the intestine (second loop, clockwise). We characterized the enzymatic profile as well as the microbial composition of the stomach and the intestine of the green sea urchin <em>Strongylocentrotus droebachiensis</em>, an ecological and economical important arctic-boreal grazer. Using qualitative and quantitative enzyme activity assays on tissue of the stomach and intestine, we identified differences in the biochemical processes, primarily concerning the protein and lipid metabolism. The stomach expressed higher esterase and esterase/lipase activity, while the intestine showed predominantly high exopeptidase activity. Low carbohydrate degrading enzyme activity suggests that polysaccharide digestion, despite their abundance in the species' diet, may primarily occur extracellularly in the lumen of the digestive tube. Our enzymatic findings are complimented by metabarcoding of the microbial community and analysis of functional properties: We found microbial taxa possibly associated with nitrogen fixation and carbohydrate degradation. Nevertheless, the composition and potential functional genes of the microbial community were similar between the two organs, suggesting that they do not play an organ-specific role in digestive processes.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111907"},"PeriodicalIF":2.1,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144668978","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}
Pub Date : 2025-07-11DOI: 10.1016/j.cbpa.2025.111905
Zhu Zhu , Shengjie Li , Caixia Lei , Tao Zhu , Jing Tian , Jinxing Du , Shina Wei , Hongmei Song
Inland saline waters, widely distributed globally, impose stringent constraints on aquaculture owing to their high osmotic pressure, preventing most aquatic organisms from surviving. As the most extensively farmed freshwater fish worldwide, the grass carp (Ctenopharyngodon idella) is confined to freshwater habitats. The adaptation of this species to saline aquaculture holds significant ecological and economic potential; however, the mechanisms underlying its osmotic regulation in hypersaline environments remain poorly understood. In this study, juvenile grass carp with a mean body weight of 15.42 ± 0.96 g were subjected to acute salinity tolerance tests across six gradients (0, 4, 7, 10, 13, and 16 ppt). The 96 h median lethal salinity concentration (LC50) was first determined, followed by the evaluation of osmoregulatory dynamics through physiological-biochemical profiling and targeted quantification of salinity-responsive gene expression under acute stress conditions. Results showed mortality exhibited salinity-dependent escalation, and the LC50–96 h was 10.58 ppt. Under 24 h salinity exposure (0, 4, 7, and 10 ppt), grass carp exhibited salinity-dependent increases in serum electrolytes (Na+, Cl−, K+) and cortisol (P < 0.05). Serum osmolality remained stable at 4 ppt and 7 ppt but increased significantly at 10 ppt. Serum prolactin showed progressive decline from 7 ppt. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the liver, kidney, and gills showed salinity-stimulated upregulation (significant at 7 and 10 ppt). Immune-related enzymes, acid phosphatase (ACP) and alkaline phosphatase (AKP), increased at 4 and 7 ppt, whereas AKP activity declined at 10 ppt. Gill Na+/K+-ATPase (NKA) activity was significantly elevated at 10 ppt (P < 0.01). Moreover, both gill and kidney structures exhibited significant alterations under 7 ppt and 10 ppt salinity stress. Specifically, the gill showed cracks in the filaments, chloride cell hyperplasia, and detachment of flattened epithelial cells; renal tubules were atrophic. The expression of ion transport-related genes NKA and solute carrier family 12 member 2 (SLC12A2) in the gills increased with increasing salinity; both genes showed significant differences at 7 ppt and 10 ppt, indicating their role in regulating osmotic pressure balance. This study provides a theoretical basis for the saline aquaculture technology and salt-tolerant variety development in grass carp.
{"title":"Survival and acute osmoregulatory response of grass carp under salinity stress","authors":"Zhu Zhu , Shengjie Li , Caixia Lei , Tao Zhu , Jing Tian , Jinxing Du , Shina Wei , Hongmei Song","doi":"10.1016/j.cbpa.2025.111905","DOIUrl":"10.1016/j.cbpa.2025.111905","url":null,"abstract":"<div><div>Inland saline waters, widely distributed globally, impose stringent constraints on aquaculture owing to their high osmotic pressure, preventing most aquatic organisms from surviving. As the most extensively farmed freshwater fish worldwide, the grass carp (<em>Ctenopharyngodon idella</em>) is confined to freshwater habitats. The adaptation of this species to saline aquaculture holds significant ecological and economic potential; however, the mechanisms underlying its osmotic regulation in hypersaline environments remain poorly understood. In this study, juvenile grass carp with a mean body weight of 15.42 ± 0.96 g were subjected to acute salinity tolerance tests across six gradients (0, 4, 7, 10, 13, and 16 ppt). The 96 h median lethal salinity concentration (LC50) was first determined, followed by the evaluation of osmoregulatory dynamics through physiological-biochemical profiling and targeted quantification of salinity-responsive gene expression under acute stress conditions. Results showed mortality exhibited salinity-dependent escalation, and the LC50–96 h was 10.58 ppt. Under 24 h salinity exposure (0, 4, 7, and 10 ppt), grass carp exhibited salinity-dependent increases in serum electrolytes (Na<sup>+</sup>, Cl<sup>−</sup>, K<sup>+</sup>) and cortisol (<em>P</em> < 0.05). Serum osmolality remained stable at 4 ppt and 7 ppt but increased significantly at 10 ppt. Serum prolactin showed progressive decline from 7 ppt. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the liver, kidney, and gills showed salinity-stimulated upregulation (significant at 7 and 10 ppt). Immune-related enzymes, acid phosphatase (ACP) and alkaline phosphatase (AKP), increased at 4 and 7 ppt, whereas AKP activity declined at 10 ppt. Gill Na<sup>+</sup>/K<sup>+</sup>-ATPase (NKA) activity was significantly elevated at 10 ppt (<em>P</em> < 0.01). Moreover, both gill and kidney structures exhibited significant alterations under 7 ppt and 10 ppt salinity stress. Specifically, the gill showed cracks in the filaments, chloride cell hyperplasia, and detachment of flattened epithelial cells; renal tubules were atrophic. The expression of ion transport-related genes <em>NKA</em> and solute carrier family 12 member 2 (<em>SLC12A2</em>) in the gills increased with increasing salinity; both genes showed significant differences at 7 ppt and 10 ppt, indicating their role in regulating osmotic pressure balance. This study provides a theoretical basis for the saline aquaculture technology and salt-tolerant variety development in grass carp.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111905"},"PeriodicalIF":2.1,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144627724","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}
Pub Date : 2025-07-10DOI: 10.1016/j.cbpa.2025.111904
Sandra Martins , Jaquelino Varela , Rute Felix , Catarina Pereira Santos , José Ricardo Paula , Deborah M. Power , Rui Rosa
The global oxygen inventory has been declining worldwide, primarily due to climate change. The importance of oxygen for aerobic respiration and its homeostasis makes declining oxygen levels a concern, particularly during energy demanding lifecycle stages. The effects of low oxygen levels on neuroendocrine responses and immune competence of developing sharks were studied in the head and trunk tissues of early (EE; before pre-hatching) and late embryos (LE) of small-spotted catshark (Scyliorhinus canicula) under six days of deoxygenation (93 % O2 of air saturation) and hypoxic conditions (26 % O2). Catshark embryos were resilient to deoxygenation, with only a 10 % decline in survival compared to the control, and only the gene expression of melanotransferrin changed. Under hypoxia, growth was unaffected, but survival decreased by 31 % compared to the control in LE, highlighting an inadequate physiological response. Developmental stage affected the expression of hypoxia-inducible factor 1 alpha (hif1a), iron metabolism and immune-related genes, pointing to critical response mechanisms. The EE stage had an optimised stress response under hypoxia compared to LE, with the upregulation of the hif1a gene. The lack of a protective response and compromised immune-related functions under hypoxia in LE raise concerns about species survival under climate change. These findings highlight the need for further research on the likely resilience of sharks to environmental challenges.
{"title":"Hypoxia impairs survival and alters immune and iron metabolism gene expression during shark early ontogeny","authors":"Sandra Martins , Jaquelino Varela , Rute Felix , Catarina Pereira Santos , José Ricardo Paula , Deborah M. Power , Rui Rosa","doi":"10.1016/j.cbpa.2025.111904","DOIUrl":"10.1016/j.cbpa.2025.111904","url":null,"abstract":"<div><div>The global oxygen inventory has been declining worldwide, primarily due to climate change. The importance of oxygen for aerobic respiration and its homeostasis makes declining oxygen levels a concern, particularly during energy demanding lifecycle stages. The effects of low oxygen levels on neuroendocrine responses and immune competence of developing sharks were studied in the head and trunk tissues of early (EE; before pre-hatching) and late embryos (LE) of small-spotted catshark (<em>Scyliorhinus canicula</em>) under six days of deoxygenation (93 % O<sub>2</sub> of air saturation) and hypoxic conditions (26 % O<sub>2</sub>). Catshark embryos were resilient to deoxygenation, with only a 10 % decline in survival compared to the control, and only the gene expression of melanotransferrin changed. Under hypoxia, growth was unaffected, but survival decreased by 31 % compared to the control in LE, highlighting an inadequate physiological response. Developmental stage affected the expression of hypoxia-inducible factor 1 alpha (<em>hif1a</em>), iron metabolism and immune-related genes, pointing to critical response mechanisms. The EE stage had an optimised stress response under hypoxia compared to LE, with the upregulation of the <em>hif1a</em> gene. The lack of a protective response and compromised immune-related functions under hypoxia in LE raise concerns about species survival under climate change. These findings highlight the need for further research on the likely resilience of sharks to environmental challenges.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111904"},"PeriodicalIF":2.1,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144621215","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}
Pub Date : 2025-07-08DOI: 10.1016/j.cbpa.2025.111903
Yang Yang , Yingjie Liu , Wenzhi Liu , Lin Han , Fangying Yuan , Jing Wang , Song Wu , Yanchun Sun , Shicheng Han
Global warming poses a critical survival challenge for cold-water economic fish, necessitating elucidation of their physiological and metabolic responses to heat stress. This study established a rainbow trout heat stress model using a gradual temperature increase protocol (from 16 °C to 20 °C over 8 days, followed by maintenance at 20 °C for 22 days) and investigated the adverse effects and adaptive strategies of rainbow trout under heat stress. Extensive congestion and steatosis observed in liver tissues suggested that heat stress induced inflammatory responses and dysregulation of lipid metabolism. Significant increases in antioxidant enzyme activities and reactive oxygen species levels (1.29-fold) indicated activation of the antioxidant defense system, and this response was insufficient to alleviate oxidative damage. Integrative transcriptomic and metabolomic analyses revealed that lipid metabolism was the most significantly altered biological process. Elevated prostaglandin D2 (1.64-fold change), driven by disruption of arachidonic acid metabolism, triggered inflammatory responses. Adaptive upregulation of linoleic acid and α-linolenic acid metabolism likely maintained membrane fluidity, enhancing the capacity for heat stress adaptation. Concurrently, adaptive activation of both GPX4A (6.73-fold change) and the heat shock proteins (LOC118938277 and hsp47) likely mitigated oxidative damage associated with heat stress in the liver. Overall, this study advances the understanding of pathological injuries and adaptive strategies in rainbow trout under heat stress and identifies candidate genes for breeding heat-tolerant strains.
{"title":"Multi-omics-based study on metabolic-physiological response to heat stress in rainbow trout (Oncorhynchus mykiss)","authors":"Yang Yang , Yingjie Liu , Wenzhi Liu , Lin Han , Fangying Yuan , Jing Wang , Song Wu , Yanchun Sun , Shicheng Han","doi":"10.1016/j.cbpa.2025.111903","DOIUrl":"10.1016/j.cbpa.2025.111903","url":null,"abstract":"<div><div>Global warming poses a critical survival challenge for cold-water economic fish, necessitating elucidation of their physiological and metabolic responses to heat stress. This study established a rainbow trout heat stress model using a gradual temperature increase protocol (from 16 °C to 20 °C over 8 days, followed by maintenance at 20 °C for 22 days) and investigated the adverse effects and adaptive strategies of rainbow trout under heat stress. Extensive congestion and steatosis observed in liver tissues suggested that heat stress induced inflammatory responses and dysregulation of lipid metabolism. Significant increases in antioxidant enzyme activities and reactive oxygen species levels (1.29-fold) indicated activation of the antioxidant defense system, and this response was insufficient to alleviate oxidative damage. Integrative transcriptomic and metabolomic analyses revealed that lipid metabolism was the most significantly altered biological process. Elevated prostaglandin D2 (1.64-fold change), driven by disruption of arachidonic acid metabolism, triggered inflammatory responses. Adaptive upregulation of linoleic acid and α-linolenic acid metabolism likely maintained membrane fluidity, enhancing the capacity for heat stress adaptation. Concurrently, adaptive activation of both <em>GPX4A</em> (6.73-fold change) and the heat shock proteins (<em>LOC118938277</em> and <em>hsp47</em>) likely mitigated oxidative damage associated with heat stress in the liver. Overall, this study advances the understanding of pathological injuries and adaptive strategies in rainbow trout under heat stress and identifies candidate genes for breeding heat-tolerant strains.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111903"},"PeriodicalIF":2.1,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144610364","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}
Pub Date : 2025-07-03DOI: 10.1016/j.cbpa.2025.111902
Subu Yatung, Amit Kumar Trivedi
Anthropogenic factors, particularly urbanization, have immense implications for the natural light-dark cycle of the species. The present study deliberates on the effects of dim light at night on the transcript expression of reproductive, steroidogenic, and metabolic gene markers in adult male tree sparrows (Passer montanus). Adult male birds were procured locally and were divided into two groups (n = 6 birds/group). Both groups were exposed to 12 h of light and 12 h of darkness, but group two (dLAN group) with a constant dim light (10 lx) during the dark hours. The experiment was run for 2 weeks. After that, birds were sampled, and the hypothalamus, liver, and gonads were harvested and used for gene expression analysis. Blood plasma was used for hormonal and biochemical assays. The findings suggest that 2 weeks of exposure did not significantly change the body mass, cholesterol, glucose, and testosterone assay. However, an increase in testicular volume was observed in dLAN-treated birds. Furthermore, elevation in hypothalamic transcripts (Tshβ, Dio2, GnRH, and Eya3) involved in the seasonal reproduction, along with an increase in steroidogenic transcripts (StAr, Scp2, Srd5a1, Hsd11b2, and Er) in the testis was observed; besides, liver metabolic transcript levels (Acaca, Fasn, Hmcg, Idh2, Sdhaf4, Sdhaf2, Sdhc, Fh, Mdh, Foxo1, and Vip) were also elevated in the dLAN-treated group compared to the control group. Overall, the study shows that even a short-term exposure to the lower intensity of dim light at night of 2 weeks of duration can stimulate the hypothalamic gonadal axis and liver metabolism in tree sparrows. These results could play a role in understanding the effect of light at night on the physiology of diurnal avian species.
{"title":"Short-term exposure to dim light at night affects reproduction and metabolism-linked processes in adult male tree sparrows (Passer montanus)","authors":"Subu Yatung, Amit Kumar Trivedi","doi":"10.1016/j.cbpa.2025.111902","DOIUrl":"10.1016/j.cbpa.2025.111902","url":null,"abstract":"<div><div>Anthropogenic factors, particularly urbanization, have immense implications for the natural light-dark cycle of the species. The present study deliberates on the effects of dim light at night on the transcript expression of reproductive, steroidogenic, and metabolic gene markers in adult male tree sparrows (<em>Passer montanus</em>). Adult male birds were procured locally and were divided into two groups (<em>n</em> = 6 birds/group). Both groups were exposed to 12 h of light and 12 h of darkness, but group two (dLAN group) with a constant dim light (10 lx) during the dark hours. The experiment was run for 2 weeks. After that, birds were sampled, and the hypothalamus, liver, and gonads were harvested and used for gene expression analysis. Blood plasma was used for hormonal and biochemical assays. The findings suggest that 2 weeks of exposure did not significantly change the body mass, cholesterol, glucose, and testosterone assay. However, an increase in testicular volume was observed in dLAN-treated birds. Furthermore, elevation in hypothalamic transcripts (<em>Tshβ</em>, <em>Dio2</em>, <em>GnRH</em>, and <em>Eya3)</em> involved in the seasonal reproduction, along with an increase in steroidogenic transcripts (<em>StAr</em>, <em>Scp2</em>, <em>Srd5a1</em>, <em>Hsd11b2</em>, and <em>Er</em>) in the testis was observed; besides, liver metabolic transcript levels (<em>Acaca</em>, <em>Fasn</em>, <em>Hmcg</em>, <em>Idh2</em>, <em>Sdhaf4</em>, <em>Sdhaf2</em>, <em>Sdhc</em>, <em>Fh</em>, <em>Mdh</em>, <em>Foxo1</em>, and <em>Vip</em>) were also elevated in the dLAN-treated group compared to the control group. Overall, the study shows that even a short-term exposure to the lower intensity of dim light at night of 2 weeks of duration can stimulate the hypothalamic gonadal axis and liver metabolism in tree sparrows. These results could play a role in understanding the effect of light at night on the physiology of diurnal avian species.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"307 ","pages":"Article 111902"},"PeriodicalIF":2.1,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144549430","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}
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