Pub Date : 2025-11-30DOI: 10.1016/j.cbpc.2025.110419
Camila de Martinez Gaspar Martins , Mariana Basso Jorge , Marina Mussoi Giacomin , Adalto Bianchini , Chris M. Wood
In vivo and in vitro experiments were conducted to test whether copper (Cu) uptake occurs via sodium (Na+) transporters in the gills of Callinectes sapidus acclimated to dilute seawater (2 ppt), a condition in which the species hyper-osmoregulates. Specific inhibitors targeting Na+/H+ exchangers (amiloride, 100 μM) and Na+, K+, 2 Cl− cotransporters (NKCC) (furosemide, 120 μM) were used. In vivo, adult crabs were exposed for 6 h to 1 μM radiolabeled Cu (64Cu) in artificial seawater or Na-free media, both at 2 ppt. In vitro, isolated posterior gills were perfused with hemolymph-like saline and exposed to external solutions containing 64Cu. Na+ uptake was first validated using radiolabeled Na (24Na) and the inhibitors: in vivo Na+ uptake was significantly reduced by amiloride (68 %) and furosemide (23 %) and in vitro amiloride reduced Na+ uptake by 40 %. Cu uptake, however, remained unaffected by the Na+ presence/absence or by the inhibitors in both experimental approaches. The 64Cu accumulated mainly in the carapace (49 %) and posterior gills (22 %), regardless of Na+ availability. The findings clearly demonstrate that Cu uptake, irrespective of the uptake pathway, proceeds independently of Na.
{"title":"Copper uptake in blue crabs is independent of sodium transport under hyposaline conditions","authors":"Camila de Martinez Gaspar Martins , Mariana Basso Jorge , Marina Mussoi Giacomin , Adalto Bianchini , Chris M. Wood","doi":"10.1016/j.cbpc.2025.110419","DOIUrl":"10.1016/j.cbpc.2025.110419","url":null,"abstract":"<div><div><em>In vivo</em> and <em>in vitro</em> experiments were conducted to test whether copper (Cu) uptake occurs <em>via</em> sodium (Na<sup>+</sup>) transporters in the gills of <em>Callinectes sapidus</em> acclimated to dilute seawater (2 ppt), a condition in which the species hyper-osmoregulates. Specific inhibitors targeting Na<sup>+</sup>/H<sup>+</sup> exchangers (amiloride, 100 μM) and Na<sup>+</sup>, K<sup>+</sup>, 2 Cl<sup>−</sup> cotransporters (NKCC) (furosemide, 120 μM) were used. <em>In vivo</em>, adult crabs were exposed for 6 h to 1 μM radiolabeled Cu (<sup>64</sup>Cu) in artificial seawater or Na-free media, both at 2 ppt. <em>In vitro</em>, isolated posterior gills were perfused with hemolymph-like saline and exposed to external solutions containing <sup>64</sup>Cu. Na<sup>+</sup> uptake was first validated using radiolabeled Na (<sup>24</sup>Na) and the inhibitors: <em>in vivo</em> Na<sup>+</sup> uptake was significantly reduced by amiloride (68 %) and furosemide (23 %) and <em>in vitro</em> amiloride reduced Na<sup>+</sup> uptake by 40 %. Cu uptake, however, remained unaffected by the Na<sup>+</sup> presence/absence or by the inhibitors in both experimental approaches. The <sup>64</sup>Cu accumulated mainly in the carapace (49 %) and posterior gills (22 %), regardless of Na<sup>+</sup> availability. The findings clearly demonstrate that Cu uptake, irrespective of the uptake pathway, proceeds independently of Na.</div></div>","PeriodicalId":10602,"journal":{"name":"Comparative Biochemistry and Physiology C-toxicology & Pharmacology","volume":"301 ","pages":"Article 110419"},"PeriodicalIF":4.3,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145658955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-29DOI: 10.1016/j.cbpc.2025.110417
Pius Abraham Tetteh , Zahra Kalvani , Don Stevens , Ravinder Sappal , Collins Kamunde
Fish frequently face fluctuations in food availability and elevated metals levels, which can independently or interactively affect physiological functions. This study examined how nutritional status and zinc (Zn) exposure influence mitochondrial bioenergetics and redox balance in rainbow trout (Oncorhynchus mykiss). Fish were subjected to three nutritional regimes: seven-day satiation, seven-day starvation, or seven-day starvation followed by a 24-h refeeding. Liver and heart mitochondria were isolated and assessed for respiration and H₂O₂ emission during oxidation of glutamate-malate (complex I, CxI) and succinate (complex II; CxII), with and without Zn (0, 25, or 50 μM). Starvation decreased body and organ mass and suppressed CxI- and CxII-linked oxidative phosphorylation (OXPHOS), LEAK respiration, and respiratory control ratio (RCR) in both organs. Refeeding restored liver mitochondrial function but only partially recovered heart function. Zn effects were tissue-, substrate-, and concentration-dependent, with heart more sensitive than liver. In liver, low Zn mitigated starvation-induced OXPHOS suppression, while high Zn impaired respiration across all conditions. Zn elevated H₂O₂ emission in satiated liver mitochondria but reduced it in starved and refed fish. In contrast, heart mitochondria showed Zn-induced respiratory inhibition and a 4–5-fold increase in H₂O₂ emission regardless of nutritional state. Starvation and refeeding alone reduced H₂O₂ emission in heart but not liver. Succinate-supported mitochondria emitted more H₂O₂ than glutamate-malate, likely via enhanced reverse electron transport. Overall, nutritional status and Zn independently and interactively shape mitochondrial function in a tissue-specific manner, highlighting the importance of considering metabolic state in metals toxicity assessments and ecological risk evaluation.
{"title":"Nutritional status modulates mitochondrial bioenergetic and redox responses to zinc exposure in rainbow trout","authors":"Pius Abraham Tetteh , Zahra Kalvani , Don Stevens , Ravinder Sappal , Collins Kamunde","doi":"10.1016/j.cbpc.2025.110417","DOIUrl":"10.1016/j.cbpc.2025.110417","url":null,"abstract":"<div><div>Fish frequently face fluctuations in food availability and elevated metals levels, which can independently or interactively affect physiological functions. This study examined how nutritional status and zinc (Zn) exposure influence mitochondrial bioenergetics and redox balance in rainbow trout (<em>Oncorhynchus mykiss</em>). Fish were subjected to three nutritional regimes: seven-day satiation, seven-day starvation, or seven-day starvation followed by a 24-h refeeding. Liver and heart mitochondria were isolated and assessed for respiration and H₂O₂ emission during oxidation of glutamate-malate (complex I, CxI) and succinate (complex II; CxII), with and without Zn (0, 25, or 50 μM). Starvation decreased body and organ mass and suppressed CxI- and CxII-linked oxidative phosphorylation (OXPHOS), LEAK respiration, and respiratory control ratio (RCR) in both organs. Refeeding restored liver mitochondrial function but only partially recovered heart function. Zn effects were tissue-, substrate-, and concentration-dependent, with heart more sensitive than liver. In liver, low Zn mitigated starvation-induced OXPHOS suppression, while high Zn impaired respiration across all conditions. Zn elevated H₂O₂ emission in satiated liver mitochondria but reduced it in starved and refed fish. In contrast, heart mitochondria showed Zn-induced respiratory inhibition and a 4–5-fold increase in H₂O₂ emission regardless of nutritional state. Starvation and refeeding alone reduced H₂O₂ emission in heart but not liver. Succinate-supported mitochondria emitted more H₂O₂ than glutamate-malate, likely <em>via</em> enhanced reverse electron transport. Overall, nutritional status and Zn independently and interactively shape mitochondrial function in a tissue-specific manner, highlighting the importance of considering metabolic state in metals toxicity assessments and ecological risk evaluation.</div></div>","PeriodicalId":10602,"journal":{"name":"Comparative Biochemistry and Physiology C-toxicology & Pharmacology","volume":"301 ","pages":"Article 110417"},"PeriodicalIF":4.3,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145647439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-29DOI: 10.1016/j.cbpc.2025.110418
Katie A. Edwards , Dennis Kleiner , Banshika M. Mangal , Bhavna S. Sonare
Thiamine (vitamin B1) deficiency is causative of reproductive failures and population declines in lake trout, Atlantic salmon, and other predatory fish species. Transketolase (TKT) is the rate-limiting enzyme of the non-oxidative phase of the pentose-phosphate pathway. TKT is critical for mediating the availability of sugars to return to glycolysis and for synthesizing NADPH and R5P, which are needed to maintain the cellular oxidation state and to produce biomolecules necessary for successful growth and reproduction. TKT activity provides a measure of functional thiamine availability since it requires thiamine diphosphate (TDP) as a coenzyme. Its activity is usually analyzed via a coupled enzyme reaction, including ribose-5-phosphate (R5P) and xylulose-5-phosphate (X5P) as substrates to permit the kinetic monitoring of the depletion of exogenous NADH. We developed a simplified, cost-effective procedure for quantifying TKT activity in fish liver to probe thiamine utilization and magnesium (Mg2+) dependence. Unlike previous protocols, the method omits costly X5P, relying instead on endogenous enzyme activity for in situ substrate generation. In two lake trout strains, TKT-specific activity correlated with TDP concentration while maximal activity reflected enzyme abundance and holoenzyme stability. By running samples with and without Mg2+ and over a range of TDP concentrations, the assay framework allows for distinguishing a Mg2+ limitation from a thiamine limitation and defines apparent EC50 and Vmax values. This simplified and tunable assay provides a tool for evaluation of thiamine-related metabolic resistance under dietary or environmental stress across fish populations and species.
{"title":"An updated transketolase activity assay to probe thiamine utilization in fish","authors":"Katie A. Edwards , Dennis Kleiner , Banshika M. Mangal , Bhavna S. Sonare","doi":"10.1016/j.cbpc.2025.110418","DOIUrl":"10.1016/j.cbpc.2025.110418","url":null,"abstract":"<div><div>Thiamine (vitamin B1) deficiency is causative of reproductive failures and population declines in lake trout, Atlantic salmon, and other predatory fish species. Transketolase (TKT) is the rate-limiting enzyme of the non-oxidative phase of the pentose-phosphate pathway. TKT is critical for mediating the availability of sugars to return to glycolysis and for synthesizing NADPH and R5P, which are needed to maintain the cellular oxidation state and to produce biomolecules necessary for successful growth and reproduction. TKT activity provides a measure of functional thiamine availability since it requires thiamine diphosphate (TDP) as a coenzyme. Its activity is usually analyzed via a coupled enzyme reaction, including ribose-5-phosphate (R5P) and xylulose-5-phosphate (X5P) as substrates to permit the kinetic monitoring of the depletion of exogenous NADH. We developed a simplified, cost-effective procedure for quantifying TKT activity in fish liver to probe thiamine utilization and magnesium (Mg<sup>2+</sup>) dependence. Unlike previous protocols, the method omits costly X5P, relying instead on endogenous enzyme activity for in situ substrate generation. In two lake trout strains, TKT-specific activity correlated with TDP concentration while maximal activity reflected enzyme abundance and holoenzyme stability. By running samples with and without Mg<sup>2+</sup> and over a range of TDP concentrations, the assay framework allows for distinguishing a Mg<sup>2+</sup> limitation from a thiamine limitation and defines apparent <em>EC</em><sub><em>50</em></sub> and <em>V</em><sub><em>max</em></sub> values. This simplified and tunable assay provides a tool for evaluation of thiamine-related metabolic resistance under dietary or environmental stress across fish populations and species.</div></div>","PeriodicalId":10602,"journal":{"name":"Comparative Biochemistry and Physiology C-toxicology & Pharmacology","volume":"300 ","pages":"Article 110418"},"PeriodicalIF":4.3,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145647480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-28DOI: 10.1016/j.cbpc.2025.110415
Laura E. Hernández-Aguirre , Laura Camacho-Jiménez , Alma B. Peregrino-Uriarte , Gloria Yepiz-Plascencia
Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants that pose a significant risk to aquatic ecosystems. This study evaluated metabolic responses in hepatopancreas, focusing on key enzymes of glycolysis and anaerobic glycolysis in the shrimp Penaeus vannamei exposed for 24 and 96 h to phenanthrene (PHE) and naphthalene (NAP). We analyzed the expression of two hexokinase genes (HK1 and HK2), and lactate dehydrogenase (LDH1 and LDH2 subunits), total enzymatic activity of HK and LDH, and intracellular glucose and lactate. NAP significantly induced the expression of HKs and LDHs at 96 h, while PHE had no significant effect. LDH2 expression was detected only in response to NAP, suggesting that this PAH enhances anaerobic metabolism, possibly due to a higher oxygen demand for NAP detoxification. Although no significant differences were detected in the total activities of HK and LDH due to exposure to the selected PAHs, a decreasing trend was detected in HK activity under NAP treatment at 24 h. Additionally, glucose decreased over time. In contrast, lactate levels increased at 24 h in response to NAP and PHE, suggesting an early shift toward anaerobic metabolism, and then returned to initial levels by 96 h. These findings highlight the effects of PAHs on energy metabolism disruption in shrimp and provide insights into the molecular responses of aquatic invertebrates to metabolic stress induced by organic pollutants.
{"title":"The polycyclic aromatic hydrocarbons phenanthrene and naphthalene affect differentially key glycolytic enzymes in the whiteleg shrimp Penaeus vannamei","authors":"Laura E. Hernández-Aguirre , Laura Camacho-Jiménez , Alma B. Peregrino-Uriarte , Gloria Yepiz-Plascencia","doi":"10.1016/j.cbpc.2025.110415","DOIUrl":"10.1016/j.cbpc.2025.110415","url":null,"abstract":"<div><div>Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants that pose a significant risk to aquatic ecosystems. This study evaluated metabolic responses in hepatopancreas, focusing on key enzymes of glycolysis and anaerobic glycolysis in the shrimp <em>Penaeus vannamei</em> exposed for 24 and 96 h to phenanthrene (PHE) and naphthalene (NAP). We analyzed the expression of two hexokinase genes (HK1 and HK2), and lactate dehydrogenase (LDH1 and LDH2 subunits), total enzymatic activity of HK and LDH, and intracellular glucose and lactate. NAP significantly induced the expression of HKs and LDHs at 96 h, while PHE had no significant effect. LDH2 expression was detected only in response to NAP, suggesting that this PAH enhances anaerobic metabolism, possibly due to a higher oxygen demand for NAP detoxification. Although no significant differences were detected in the total activities of HK and LDH due to exposure to the selected PAHs, a decreasing trend was detected in HK activity under NAP treatment at 24 h. Additionally, glucose decreased over time. In contrast, lactate levels increased at 24 h in response to NAP and PHE, suggesting an early shift toward anaerobic metabolism, and then returned to initial levels by 96 h. These findings highlight the effects of PAHs on energy metabolism disruption in shrimp and provide insights into the molecular responses of aquatic invertebrates to metabolic stress induced by organic pollutants.</div></div>","PeriodicalId":10602,"journal":{"name":"Comparative Biochemistry and Physiology C-toxicology & Pharmacology","volume":"300 ","pages":"Article 110415"},"PeriodicalIF":4.3,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145647473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-28DOI: 10.1016/j.cbpc.2025.110416
Jennifer S. Jensen , Peyman Owrang , Avery Sherffius , Claire Selby , Nathaniel R. Fleming , Logan Ouellette , Matthew Hartings , Victoria P. Connaughton
Tributyltin (TBT) is an antiestrogenic endocrine disrupting compound used in the production of plastic, timber, and aquatic antifouling paints. Previous studies focusing on short-term effects of TBT exposure have identified immediate detrimental effects. Here, we evaluate whether a transient (24 h) exposure to TBT during development can cause persistent effects that remain after removal from treatment. Zebrafish (Danio rerio) larvae were exposed to environmentally relevant concentrations of TBT (0.04 and 0.4 μg/L) when they were either 3- or 7-days post-fertilization (dpf). After exposure, larvae were returned to recovery conditions and assessed 2-weeks, 4-weeks, or > 5 months postexposure. Exposure to 0.4 μg/L TBT at 3 dpf decreased total and distal retinal thicknesses. Adult (>5 month) photopic electroretinograms revealed physiological changes to photoreceptor a-wave and ON-bipolar cell b-wave components, with greater deficits in the 0.4 μg/L group. TBT exposure at 7 dpf significantly increased retinal inner plexiform layer thickness at 2-weeks, an effect that persisted to adulthood. Adult electroretinograms were also altered, with 0.04 μg/L TBT increasing and delaying a-wave and OFF-bipolar d-wave responses and increasing b-wave amplitude. Thus, the impact of TBT exposure depends on both concentration and exposure age, with retinal sequelae characterized by early anatomical and later physiological deficits. These data suggest that TBT exposure during critical periods of visual system development causes persistent age- and concentration-dependent deficits that are specific to the retina, revealing a previously unknown effect of this compound.
{"title":"Early life tributyltin exposure has long term physiological effects on the zebrafish (Danio rerio) visual system","authors":"Jennifer S. Jensen , Peyman Owrang , Avery Sherffius , Claire Selby , Nathaniel R. Fleming , Logan Ouellette , Matthew Hartings , Victoria P. Connaughton","doi":"10.1016/j.cbpc.2025.110416","DOIUrl":"10.1016/j.cbpc.2025.110416","url":null,"abstract":"<div><div>Tributyltin (TBT) is an antiestrogenic endocrine disrupting compound used in the production of plastic, timber, and aquatic antifouling paints. Previous studies focusing on short-term effects of TBT exposure have identified immediate detrimental effects. Here, we evaluate whether a transient (24 h) exposure to TBT during development can cause persistent effects that remain after removal from treatment. Zebrafish (<em>Danio rerio</em>) larvae were exposed to environmentally relevant concentrations of TBT (0.04 and 0.4 μg/L) when they were either 3- or 7-days post-fertilization (dpf). After exposure, larvae were returned to recovery conditions and assessed 2-weeks, 4-weeks, or > 5 months postexposure. Exposure to 0.4 μg/L TBT at 3 dpf decreased total and distal retinal thicknesses. Adult (>5 month) photopic electroretinograms revealed physiological changes to photoreceptor a-wave and ON-bipolar cell b-wave components, with greater deficits in the 0.4 μg/L group. TBT exposure at 7 dpf significantly increased retinal inner plexiform layer thickness at 2-weeks, an effect that persisted to adulthood. Adult electroretinograms were also altered, with 0.04 μg/L TBT increasing and delaying a-wave and OFF-bipolar d-wave responses and increasing b-wave amplitude. Thus, the impact of TBT exposure depends on both concentration and exposure age, with retinal sequelae characterized by early anatomical and later physiological deficits. These data suggest that TBT exposure during critical periods of visual system development causes persistent age- and concentration-dependent deficits that are specific to the retina, revealing a previously unknown effect of this compound.</div></div>","PeriodicalId":10602,"journal":{"name":"Comparative Biochemistry and Physiology C-toxicology & Pharmacology","volume":"301 ","pages":"Article 110416"},"PeriodicalIF":4.3,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145647435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-23DOI: 10.1016/j.cbpc.2025.110402
Abdul Haleem Khan , Muhammad Jawad , Sana Nasir , Haijing Xu , Mengzhou Wu , Junqiang Qiu , Mingyou Li
Copper (Cu2+), though essential as a micronutrient, can pose significant ecotoxicological risks when introduced into aquatic environments at elevated levels, primarily due to anthropogenic sources such as industrial discharge, agricultural runoff, and urban effluents. This study investigated the long-term effects of environmentally relevant copper concentrations (0, 5, 10, and 20 μg/L) on Japanese medaka (Oryzias latipes) over a six-month exposure period, focusing on reproductive toxicity, oxidative stress, immune response, and gut microbiota alterations. Histopathological analysis revealed gonadal impairments, including disrupted testicular and ovarian structures, impaired spermatogenesis, and reduced oocyte maturation. Additionally, hormonal changes revealed elevated levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol (E2), alongside reduced testosterone (T) levels, indicating interference with the hypothalamic–pituitary–gonadal (HPG) axis. Copper exposure also altered antioxidant enzyme activities, including sex-dependent modulation of superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) levels, indicating oxidative imbalance and compensatory defense responses, along with upregulation of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α). Gut microbiota analysis via 16S rRNA sequencing revealed significant dysbiosis, characterized by marked reductions in alpha diversity indices and distinct beta diversity clustering. Taxonomic profiling showed a sharp decline in beneficial phyla such as Fusobacteriota, Firmicutes, and Actinobacteriota, coupled with an enrichment of potentially opportunistic Proteobacteria and shifts in Bacteroidota and Verrucomicrobiota, indicating compromised intestinal homeostasis. Collectively, these findings demonstrate that chronic exposure to copper ions induces multi-systemic toxicity in O. latipes, impairing reproductive function, provoking oxidative and inflammatory responses, and reshaping gut microbial communities in ways that may exacerbate host physiological stress.
{"title":"Chronic copper exposure induces multi-systemic toxicity in Japanese medaka (Oryzias latipes) via reproductive disruption, and gut microbiota dysbiosis","authors":"Abdul Haleem Khan , Muhammad Jawad , Sana Nasir , Haijing Xu , Mengzhou Wu , Junqiang Qiu , Mingyou Li","doi":"10.1016/j.cbpc.2025.110402","DOIUrl":"10.1016/j.cbpc.2025.110402","url":null,"abstract":"<div><div>Copper (Cu<sup>2+</sup>), though essential as a micronutrient, can pose significant ecotoxicological risks when introduced into aquatic environments at elevated levels, primarily due to anthropogenic sources such as industrial discharge, agricultural runoff, and urban effluents. This study investigated the long-term effects of environmentally relevant copper concentrations (0, 5, 10, and 20 μg/L) on Japanese medaka (<em>Oryzias latipes</em>) over a six-month exposure period, focusing on reproductive toxicity, oxidative stress, immune response, and gut microbiota alterations. Histopathological analysis revealed gonadal impairments, including disrupted testicular and ovarian structures, impaired spermatogenesis, and reduced oocyte maturation. Additionally, hormonal changes revealed elevated levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol (E2), alongside reduced testosterone (T) levels, indicating interference with the hypothalamic–pituitary–gonadal (HPG) axis. Copper exposure also altered antioxidant enzyme activities, including sex-dependent modulation of superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) levels, indicating oxidative imbalance and compensatory defense responses, along with upregulation of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α). Gut microbiota analysis via 16S rRNA sequencing revealed significant dysbiosis, characterized by marked reductions in alpha diversity indices and distinct beta diversity clustering. Taxonomic profiling showed a sharp decline in beneficial phyla such as Fusobacteriota, Firmicutes, and Actinobacteriota, coupled with an enrichment of potentially opportunistic <em>Proteobacteria</em> and shifts in <em>Bacteroidota</em> and <em>Verrucomicrobiota</em>, indicating compromised intestinal homeostasis. Collectively, these findings demonstrate that chronic exposure to copper ions induces multi-systemic toxicity in <em>O. latipes</em>, impairing reproductive function, provoking oxidative and inflammatory responses, and reshaping gut microbial communities in ways that may exacerbate host physiological stress.</div></div>","PeriodicalId":10602,"journal":{"name":"Comparative Biochemistry and Physiology C-toxicology & Pharmacology","volume":"300 ","pages":"Article 110402"},"PeriodicalIF":4.3,"publicationDate":"2025-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145602794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-23DOI: 10.1016/j.cbpc.2025.110403
Yuanhua Wang , Jie Ren , Siling Zhang , Hao Xu
The tire-derived antioxidant 6PPD (N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine), a ubiquitous environmental contaminant, poses significant risks to aquatic ecosystems, yet its sex-specific physiological impacts remain underexplored. This study investigated the effects of environmentally relevant 6PPD concentrations (20 μg/L) on feeding, digestion, absorption, and reproduction in adult zebrafish over 28 days. Results revealed pronounced male-specific impairments: 6PPD-exposed males exhibited reduced feeding speed and maximum food intake, alongside suppressed locomotor responses to food stimuli. Mechanistically, upregulation of intestinal cholecystokinin b (cckb) and delayed intestinal content emptying were identified as potential drivers of feeding inhibition in males. Concurrently, 6PPD induced intestinal oxidative stress in males, manifested through decreased activities of catalase (CAT) and superoxide dismutase (SOD), alongside elevated malondialdehyde (MDA) levels, and activated ferroptosis via dysregulation of critical genes (gpx4a, cybb, slc7a11, hmox1a, tfr1b and trf2). These disruptions correlated with shortened intestinal villi, goblet cell loss, and impaired nutrient absorption, leading to increased fecal output and diminished growth performance in males. In contrast, females displayed no significant structural damage to intestinal epithelium or declines in digestive and absorptive capacities. Notably, 6PPD caused no gonadal histopathological changes, hormonal dysregulation, reduced fertilization and hatching rates, nor transgenerational effects such as developmental abnormalities or locomotor deficits in offspring. This study provides the first evidence of male-selective feeding suppression and intestinal toxicity induced by 6PPD, highlighting sex-dependent vulnerability in aquatic species and underscoring the need for gender-specific risk assessments of tire-derived pollutants.
{"title":"Sex-specific effects of 6PPD on adult zebrafish: male-selective feeding inhibition, nutrient malabsorption, intestinal epithelial damage, and absence of reproductive toxicity","authors":"Yuanhua Wang , Jie Ren , Siling Zhang , Hao Xu","doi":"10.1016/j.cbpc.2025.110403","DOIUrl":"10.1016/j.cbpc.2025.110403","url":null,"abstract":"<div><div>The tire-derived antioxidant 6PPD (N-(1,3-dimethylbutyl)-<em>N</em>′-phenyl-<em>p</em>-phenylenediamine), a ubiquitous environmental contaminant, poses significant risks to aquatic ecosystems, yet its sex-specific physiological impacts remain underexplored. This study investigated the effects of environmentally relevant 6PPD concentrations (20 μg/L) on feeding, digestion, absorption, and reproduction in adult zebrafish over 28 days. Results revealed pronounced male-specific impairments: 6PPD-exposed males exhibited reduced feeding speed and maximum food intake, alongside suppressed locomotor responses to food stimuli. Mechanistically, upregulation of intestinal cholecystokinin b (<em>cckb</em>) and delayed intestinal content emptying were identified as potential drivers of feeding inhibition in males. Concurrently, 6PPD induced intestinal oxidative stress in males, manifested through decreased activities of catalase (CAT) and superoxide dismutase (SOD), alongside elevated malondialdehyde (MDA) levels, and activated ferroptosis via dysregulation of critical genes (<em>gpx4a</em>, <em>cybb</em>, <em>slc7a11</em>, <em>hmox1a</em>, <em>tfr1b</em> and <em>trf2</em>). These disruptions correlated with shortened intestinal villi, goblet cell loss, and impaired nutrient absorption, leading to increased fecal output and diminished growth performance in males. In contrast, females displayed no significant structural damage to intestinal epithelium or declines in digestive and absorptive capacities. Notably, 6PPD caused no gonadal histopathological changes, hormonal dysregulation, reduced fertilization and hatching rates, nor transgenerational effects such as developmental abnormalities or locomotor deficits in offspring. This study provides the first evidence of male-selective feeding suppression and intestinal toxicity induced by 6PPD, highlighting sex-dependent vulnerability in aquatic species and underscoring the need for gender-specific risk assessments of tire-derived pollutants.</div></div>","PeriodicalId":10602,"journal":{"name":"Comparative Biochemistry and Physiology C-toxicology & Pharmacology","volume":"300 ","pages":"Article 110403"},"PeriodicalIF":4.3,"publicationDate":"2025-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145602782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-22DOI: 10.1016/j.cbpc.2025.110395
Ruo-Yu Zhou , Lu Chen , Meng-Yang Hu, Mu-Xi Li, Yu-Xuan Fei, Mei Huang, Yun-Long Zhang
Ammonia is a common environmental pollutant that is extremely toxic to aquatic animals. Therefore, there is an urgent need to increase ammonia tolerance in aquaculture animals to achieve high-quality development of the industry. Three treatments were designed to examine the effects of taurine on the large-scale loach (Paramisgurnus dabryanus). These were a control group (exposed to water and injected with physiological saline), an ammonia treatment group (exposed to 30 mmol/L NH4Cl solution and injected with physiological saline), and a taurine treatment group (exposed to 30 mmol/L NH4Cl solution and injected with taurine). Immune- and ammonia metabolism-related markers were measured at 12 h, 24 h, 48 h, and 96 h after treatment. The results showed that ammonia exposure significantly increased T-SOD activity and the level of IL-1β, significantly decreased IgM, C3, and TNF-α levels, and induced significantly high expression of immune-related genes (lyz, hsp70, tlr5, and myd88) in tissues. Intraperitoneal injection of taurine mitigated ammonia-induced disturbances in plasma glucose and osmotic pressure by regulating glucose metabolism and osmotic pressure balance. The results suggest that ammonia stress causes significant immune stimulation in large-scale loaches, and that taurine could alleviate this effect. Exposure to ammonia increases the concentration of ammonia in the gut, liver, kidneys, and gills of large-scale loach, significantly increases GDH and GS activity, and upregulates the expression levels of ammonia transporter-related genes such as aqps and rh. After taurine treatment, the concentration of ammonia in the somatic tissues of large-scale loaches significantly decreased, while the expression of ammonia transporter-related genes was inhibited, and the activities of GS was further enhanced. This indicates that large-scale loach initiate glutamine synthesis and upregulate ammonia transporter proteins to cope with the stress of highly concentrated ammonia, and that taurine can promote glutamine synthesis to decrease the in vivo ammonia concentration. The results can deepen our understanding of the toxicological effects of ammonia and the mechanisms by which taurine promotes ammonia tolerance in fishes, offering a basis for taurine application in aquaculture.
{"title":"Effects of taurine on immunity and ammonia metabolism in large-scale loach under ammonia stress","authors":"Ruo-Yu Zhou , Lu Chen , Meng-Yang Hu, Mu-Xi Li, Yu-Xuan Fei, Mei Huang, Yun-Long Zhang","doi":"10.1016/j.cbpc.2025.110395","DOIUrl":"10.1016/j.cbpc.2025.110395","url":null,"abstract":"<div><div>Ammonia is a common environmental pollutant that is extremely toxic to aquatic animals. Therefore, there is an urgent need to increase ammonia tolerance in aquaculture animals to achieve high-quality development of the industry. Three treatments were designed to examine the effects of taurine on the large-scale loach (<em>Paramisgurnus dabryanus</em>). These were a control group (exposed to water and injected with physiological saline), an ammonia treatment group (exposed to 30 mmol/L NH<sub>4</sub>Cl solution and injected with physiological saline), and a taurine treatment group (exposed to 30 mmol/L NH<sub>4</sub>Cl solution and injected with taurine). Immune- and ammonia metabolism-related markers were measured at 12 h, 24 h, 48 h, and 96 h after treatment. The results showed that ammonia exposure significantly increased T-SOD activity and the level of IL-1β, significantly decreased IgM, C3, and TNF-α levels, and induced significantly high expression of immune-related genes (<em>lyz</em>, <em>hsp70</em>, <em>tlr5</em>, and <em>myd88</em>) in tissues. Intraperitoneal injection of taurine mitigated ammonia-induced disturbances in plasma glucose and osmotic pressure by regulating glucose metabolism and osmotic pressure balance. The results suggest that ammonia stress causes significant immune stimulation in large-scale loaches, and that taurine could alleviate this effect. Exposure to ammonia increases the concentration of ammonia in the gut, liver, kidneys, and gills of large-scale loach, significantly increases GDH and GS activity, and upregulates the expression levels of ammonia transporter-related genes such as <em>aqps</em> and <em>rh</em>. After taurine treatment, the concentration of ammonia in the somatic tissues of large-scale loaches significantly decreased, while the expression of ammonia transporter-related genes was inhibited, and the activities of GS was further enhanced. This indicates that large-scale loach initiate glutamine synthesis and upregulate ammonia transporter proteins to cope with the stress of highly concentrated ammonia, and that taurine can promote glutamine synthesis to decrease the in vivo ammonia concentration. The results can deepen our understanding of the toxicological effects of ammonia and the mechanisms by which taurine promotes ammonia tolerance in fishes, offering a basis for taurine application in aquaculture.</div></div>","PeriodicalId":10602,"journal":{"name":"Comparative Biochemistry and Physiology C-toxicology & Pharmacology","volume":"300 ","pages":"Article 110395"},"PeriodicalIF":4.3,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145596069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-22DOI: 10.1016/j.cbpc.2025.110401
Cameron M. Emadi , Fabio Dos Santos Neto , Jason R. Bohenek , Breana Smithers , Miguel F. Acevedo , Edward M. Mager
Macrobrachium rosenbergii, the giant freshwater prawn, is an important aquaculture species cultivated worldwide. As a catadromous species, it requires brackish water for early development (larval stages) and grows optimally under low-salinity conditions. This tolerance enables production using brackish groundwater or desalination concentrate, helping reduce disposal costs. However, aquaculture systems often accumulate nitrogenous waste such as ammonia, which can negatively affect growth, survival, and health. The interactive effects of ammonia and salinity on M. rosenbergii remained understudied, particularly during juvenile stages that coincide with the transition to brackish water. Therefore, we first determined the 3, 6, 24, and 48 h median lethal concentrations (LC50) of total ammonia nitrogen (TAN) across three salinities (1, 5, and 10 ppt) at pH 8.2. Toxicity increased with both salinity and exposure time, with LC50 values ranging from 5.6 mg/L (95 % CI: 4.9–6.3) to 42 mg/L (95 % CI: 37–48) TAN. Based on these LC50 values, we tested how increasing waterborne ammonia concentrations affect the routine metabolic rate (RMR) of juvenile M. rosenbergii using static intermittent respirometry. Analysis by a linear mixed-effects model revealed a significant salinity × ammonia interaction where the positive relationship between ammonia concentration and RMR became steeper at higher salinities. The model also identified a significant main effect of ammonia, with RMR increasing as ammonia concentration rose, but no significant main effect of salinity. These findings inform aquaculture management of M. rosenbergii and demonstrate the potential for sentinel respirometry systems to detect real-time water quality changes by monitoring metabolic rates.
{"title":"Acute toxicity assessment and real-time metabolic rate responses of early life stage Macrobrachium rosenbergii to ammonia exposures at different salinities","authors":"Cameron M. Emadi , Fabio Dos Santos Neto , Jason R. Bohenek , Breana Smithers , Miguel F. Acevedo , Edward M. Mager","doi":"10.1016/j.cbpc.2025.110401","DOIUrl":"10.1016/j.cbpc.2025.110401","url":null,"abstract":"<div><div><em>Macrobrachium rosenbergii</em>, the giant freshwater prawn, is an important aquaculture species cultivated worldwide. As a catadromous species, it requires brackish water for early development (larval stages) and grows optimally under low-salinity conditions. This tolerance enables production using brackish groundwater or desalination concentrate, helping reduce disposal costs. However, aquaculture systems often accumulate nitrogenous waste such as ammonia, which can negatively affect growth, survival, and health. The interactive effects of ammonia and salinity on <em>M. rosenbergii</em> remained understudied, particularly during juvenile stages that coincide with the transition to brackish water. Therefore, we first determined the 3, 6, 24, and 48 h median lethal concentrations (LC<sub>50</sub>) of total ammonia nitrogen (TAN) across three salinities (1, 5, and 10 ppt) at pH 8.2. Toxicity increased with both salinity and exposure time, with LC<sub>50</sub> values ranging from 5.6 mg/L (95 % CI: 4.9–6.3) to 42 mg/L (95 % CI: 37–48) TAN. Based on these LC<sub>50</sub> values, we tested how increasing waterborne ammonia concentrations affect the routine metabolic rate (RMR) of juvenile <em>M. rosenbergii</em> using static intermittent respirometry. Analysis by a linear mixed-effects model revealed a significant salinity × ammonia interaction where the positive relationship between ammonia concentration and RMR became steeper at higher salinities. The model also identified a significant main effect of ammonia, with RMR increasing as ammonia concentration rose, but no significant main effect of salinity. These findings inform aquaculture management of <em>M. rosenbergii</em> and demonstrate the potential for sentinel respirometry systems to detect real-time water quality changes by monitoring metabolic rates.</div></div>","PeriodicalId":10602,"journal":{"name":"Comparative Biochemistry and Physiology C-toxicology & Pharmacology","volume":"300 ","pages":"Article 110401"},"PeriodicalIF":4.3,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145596032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-20DOI: 10.1016/j.cbpc.2025.110400
Duck-Hyun Kim , Jin-Sol Lee , Min-Sub Kim , Zhou Yang , Atsushi Hagiwara , Jae-Seong Lee
Diaphanosoma celebensis, a marine water flea, has gained recognition as a valuable model organism in marine ecotoxicology, ecophysiology, and epigenetics. This review highlights the significance of D. celebensis in environmental research, emphasizing its high-quality genomic and transcriptomic resources, adaptability to environmental stressors, and sensitivity to pollutants. The species' utility in studying molecular responses to contaminants such as microplastics, heavy metals, and endocrine disruptors is underscored by its ability to provide insights into detoxification pathways, stress response mechanisms, and epigenetic modifications. Diaphanosoma celebensis serves as a critical tool for advancing our understanding of the ecological impacts of pollution and the adaptive capacities of marine invertebrates. This review synthesizes existing research, explores the species' strengths as a research model, and identifies future research directions. All evidence suggests D. celebensis can complement traditional freshwater models and enhance our capacity to monitor and protect marine health.
{"title":"The marine water flea Diaphanosoma celebensis as an emerging model for ocean health research: A review","authors":"Duck-Hyun Kim , Jin-Sol Lee , Min-Sub Kim , Zhou Yang , Atsushi Hagiwara , Jae-Seong Lee","doi":"10.1016/j.cbpc.2025.110400","DOIUrl":"10.1016/j.cbpc.2025.110400","url":null,"abstract":"<div><div><em>Diaphanosoma celebensis</em>, a marine water flea, has gained recognition as a valuable model organism in marine ecotoxicology, ecophysiology, and epigenetics. This review highlights the significance of <em>D. celebensis</em> in environmental research, emphasizing its high-quality genomic and transcriptomic resources, adaptability to environmental stressors, and sensitivity to pollutants. The species' utility in studying molecular responses to contaminants such as microplastics, heavy metals, and endocrine disruptors is underscored by its ability to provide insights into detoxification pathways, stress response mechanisms, and epigenetic modifications. <em>Diaphanosoma celebensis</em> serves as a critical tool for advancing our understanding of the ecological impacts of pollution and the adaptive capacities of marine invertebrates. This review synthesizes existing research, explores the species' strengths as a research model, and identifies future research directions. All evidence suggests <em>D. celebensis</em> can complement traditional freshwater models and enhance our capacity to monitor and protect marine health.</div></div>","PeriodicalId":10602,"journal":{"name":"Comparative Biochemistry and Physiology C-toxicology & Pharmacology","volume":"300 ","pages":"Article 110400"},"PeriodicalIF":4.3,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145581979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号