Pub Date : 2026-02-06DOI: 10.1016/j.cbpb.2026.111205
Xingda Jia, Xiaochen Zhang, Haoyu Zhang, Yijing Han, Xiaotong Wang
Shell color is a vital economic trait of the Pacific oyster (Crassostrea gigas). However, the metabolic regulation underlying melanin deposition remains elusive. Analyses of black shell and white shell oyster strains often reflect systemic physiological differences (e.g., growth variations) that can obscure localized pigmentary signals. To reduce these systemic confounders, this study characterized metabolic profiles of excised black and white mantle tissue regions within the same individuals to identify direct pigment-related metabolic signatures. Untargeted liquid chromatography-mass spectrometry metabolomics was used to identify 527 differential metabolites. This assessment showed that in black mantle regions tyrosine metabolism was altered, and while dopamine concentrations remained stable, catecholamine-related metabolites were downregulated. Concurrently, elevated glutathione concentrations were identified in black mantle regions, which may create a reductive microenvironment that helps maintain redox homeostasis during melanogenesis. Increased spermidine concentrations were also identified in black mantle regions, which may indirectly modulate melanogenesis. Furthermore, in black mantle regions citrate cycle intermediates and lipids were downregulated suggesting a metabolic shift to support high-intensity biosynthesis. These findings provide a novel biochemical perspective on mollusk coloration, highlighting that melanin pigmentation is a highly regulated metabolic process that balances substrate competition, redox regulation, and energy allocation.
{"title":"Region-specific metabolomics reveals the mechanisms underlying melanin synthesis in Pacific oyster (Crassostrea gigas) mantle.","authors":"Xingda Jia, Xiaochen Zhang, Haoyu Zhang, Yijing Han, Xiaotong Wang","doi":"10.1016/j.cbpb.2026.111205","DOIUrl":"https://doi.org/10.1016/j.cbpb.2026.111205","url":null,"abstract":"<p><p>Shell color is a vital economic trait of the Pacific oyster (Crassostrea gigas). However, the metabolic regulation underlying melanin deposition remains elusive. Analyses of black shell and white shell oyster strains often reflect systemic physiological differences (e.g., growth variations) that can obscure localized pigmentary signals. To reduce these systemic confounders, this study characterized metabolic profiles of excised black and white mantle tissue regions within the same individuals to identify direct pigment-related metabolic signatures. Untargeted liquid chromatography-mass spectrometry metabolomics was used to identify 527 differential metabolites. This assessment showed that in black mantle regions tyrosine metabolism was altered, and while dopamine concentrations remained stable, catecholamine-related metabolites were downregulated. Concurrently, elevated glutathione concentrations were identified in black mantle regions, which may create a reductive microenvironment that helps maintain redox homeostasis during melanogenesis. Increased spermidine concentrations were also identified in black mantle regions, which may indirectly modulate melanogenesis. Furthermore, in black mantle regions citrate cycle intermediates and lipids were downregulated suggesting a metabolic shift to support high-intensity biosynthesis. These findings provide a novel biochemical perspective on mollusk coloration, highlighting that melanin pigmentation is a highly regulated metabolic process that balances substrate competition, redox regulation, and energy allocation.</p>","PeriodicalId":55236,"journal":{"name":"Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology","volume":" ","pages":"111205"},"PeriodicalIF":1.8,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146144681","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 : 2026-02-02DOI: 10.1016/j.cbpb.2026.111193
Minglang Chen, Yongtao Liu, Xianyong Bu, Zhiwei Chen, Jinze Zhang, Md Golam Sajed Riar, Yuhang Tang, Jianlong Du, Chuanwei Yao, Changxu Sui, Kangsen Mai, Qinghui Ai
An 8-week experiment was conducted to evaluate the effects of dietary phosphatidylserine (PS) supplementation on juvenile large yellow croaker (Larimichthys crocea) fed high soybean oil (SO) diets. A fish oil control, an SO control, and four SO-based diets supplemented with 0.002%, 0.006%, 0.018%, or 0.054% PS were formulated. Results showed that weight gain exhibited quadratic responses to increasing PS levels. PS supplementation alleviated hepatic lipid deposition and reduced serum and hepatic lipid concentrations. At the molecular level, PS downregulated hepatic lipogenic gene expression including sterol regulatory element-binding protein 1 (srebp1), fatty acid synthase (fas), stearoyl-CoA desaturase 1 (scd1), and acetyl-CoA carboxylase 1 (acc1). Conversely, it upregulated hepatic lipid catabolism genes: peroxisome proliferator-activated receptor a (ppara), lipoprotein lipase (lpl), carnitine palmitoyltransferase 1 (cpt1), and diacylglycerol O-acyltransferase 1 (dgat1). Additionally, PS restored antioxidant enzyme activities and the expression of superoxide dismutase (sod1, sod3), glutathione peroxidase (gpx), and catalase (cat) in the liver. Furthermore, PS reduced hepatic pro-inflammatory cytokine mRNA levels: tumor necrosis factor α(tnf-α), cyclooxygenase 2 (cox-2), and interleukins (il-6, il-1β). In conclusion, dietary inclusion of 0.006%-0.018% PS effectively enhanced growth and antioxidant capacity, altered lipid handling, and affected transcriptional inflammatory responses.
{"title":"Effects of phosphatidylserine supplementation on growth performance, lipid metabolism, antioxidant capacity, and inflammatory response of juvenile large yellow croaker (Larimichthys crocea) fed with high soybean oil diets.","authors":"Minglang Chen, Yongtao Liu, Xianyong Bu, Zhiwei Chen, Jinze Zhang, Md Golam Sajed Riar, Yuhang Tang, Jianlong Du, Chuanwei Yao, Changxu Sui, Kangsen Mai, Qinghui Ai","doi":"10.1016/j.cbpb.2026.111193","DOIUrl":"https://doi.org/10.1016/j.cbpb.2026.111193","url":null,"abstract":"<p><p>An 8-week experiment was conducted to evaluate the effects of dietary phosphatidylserine (PS) supplementation on juvenile large yellow croaker (Larimichthys crocea) fed high soybean oil (SO) diets. A fish oil control, an SO control, and four SO-based diets supplemented with 0.002%, 0.006%, 0.018%, or 0.054% PS were formulated. Results showed that weight gain exhibited quadratic responses to increasing PS levels. PS supplementation alleviated hepatic lipid deposition and reduced serum and hepatic lipid concentrations. At the molecular level, PS downregulated hepatic lipogenic gene expression including sterol regulatory element-binding protein 1 (srebp1), fatty acid synthase (fas), stearoyl-CoA desaturase 1 (scd1), and acetyl-CoA carboxylase 1 (acc1). Conversely, it upregulated hepatic lipid catabolism genes: peroxisome proliferator-activated receptor a (ppara), lipoprotein lipase (lpl), carnitine palmitoyltransferase 1 (cpt1), and diacylglycerol O-acyltransferase 1 (dgat1). Additionally, PS restored antioxidant enzyme activities and the expression of superoxide dismutase (sod1, sod3), glutathione peroxidase (gpx), and catalase (cat) in the liver. Furthermore, PS reduced hepatic pro-inflammatory cytokine mRNA levels: tumor necrosis factor α(tnf-α), cyclooxygenase 2 (cox-2), and interleukins (il-6, il-1β). In conclusion, dietary inclusion of 0.006%-0.018% PS effectively enhanced growth and antioxidant capacity, altered lipid handling, and affected transcriptional inflammatory responses.</p>","PeriodicalId":55236,"journal":{"name":"Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology","volume":" ","pages":"111193"},"PeriodicalIF":1.8,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146121215","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 : 2026-01-21DOI: 10.1016/j.cbpb.2026.111204
Zulvikar Syambani Ulhaq , Mitsuyo Kishida
Aromatase, the key enzyme for estrogen biosynthesis, is present in zebrafish as two isoforms: the ovarian form (cyp19a1a; Aromatase A (AroA)) and the brain form (cyp19a1b; Aromatase B (AroB)). Here, we investigated the role of AroA in early cardiac development. RT-PCR and immunostaining demonstrated that only AroA, and not AroB, is expressed in the zebrafish heart, specifically in atrial and ventricular cardiomyocytes and smooth muscle cells of the bulbus arteriosus. Dot blot analysis and whole-mount immunostaining confirmed the reduction of AroA expression in AroA morphants at 2 days post-fertilization (dpf). Phenotypic analysis revealed impaired yolk sac extension and reduced heart size, accompanied by significant downregulation of yolk-associated mRNA expression (vitellogenin 1 (vtg1), ribonuclease-like 2 (rnasel2)) and cardiac development genes (myosin light chain 7 (myl7), natriuretic peptide A (nppa), leucine-rich repeat-containing protein 10 (lrrc10)). Moreover, AroA knockdown suppressed dopamine β-hydroxylase (DBH) protein expression in catecholaminergic cells and significantly reduced heart rate. Morphological assessment using cardiac myosin light chain 2 (cmlc2):GFP and histological staining showed normal cardiac looping but smaller ventricular chambers. Additionally, morphants exhibited reduced end-systolic volume (ESV) and end-diastolic volume (EDV), accompanied by decreases in stroke volume (SV), cardiac output (CO), and ventricular fractional shortening (FS%). Altogether, these findings demonstrate that AroA is an essential regulator of zebrafish heart morphogenesis and function.
{"title":"The role of ovarian aromatase (cyp19a1a) in zebrafish cardiac formation and function","authors":"Zulvikar Syambani Ulhaq , Mitsuyo Kishida","doi":"10.1016/j.cbpb.2026.111204","DOIUrl":"10.1016/j.cbpb.2026.111204","url":null,"abstract":"<div><div>Aromatase, the key enzyme for estrogen biosynthesis, is present in zebrafish as two isoforms: the ovarian form (<em>cyp19a1a</em>; Aromatase A (AroA)) and the brain form (<em>cyp19a1b</em>; Aromatase B (AroB)). Here, we investigated the role of AroA in early cardiac development. RT-PCR and immunostaining demonstrated that only AroA, and not AroB, is expressed in the zebrafish heart, specifically in atrial and ventricular cardiomyocytes and smooth muscle cells of the bulbus arteriosus. Dot blot analysis and whole-mount immunostaining confirmed the reduction of AroA expression in AroA morphants at 2 days post-fertilization (dpf). Phenotypic analysis revealed impaired yolk sac extension and reduced heart size, accompanied by significant downregulation of yolk-associated mRNA expression (vitellogenin 1 (<em>vtg1</em>), ribonuclease-like 2 (<em>rnasel2</em>)) and cardiac development genes (myosin light chain 7 (<em>myl7</em>), natriuretic peptide A (<em>nppa</em>), leucine-rich repeat-containing protein 10 (<em>lrrc10</em>)). Moreover, AroA knockdown suppressed dopamine β-hydroxylase (DBH) protein expression in catecholaminergic cells and significantly reduced heart rate. Morphological assessment using cardiac myosin light chain 2 (<em>cmlc2</em>)<em>:</em>GFP and histological staining showed normal cardiac looping but smaller ventricular chambers. Additionally, morphants exhibited reduced end-systolic volume (ESV) and end-diastolic volume (EDV), accompanied by decreases in stroke volume (SV), cardiac output (CO), and ventricular fractional shortening (FS%). Altogether, these findings demonstrate that AroA is an essential regulator of zebrafish heart morphogenesis and function.</div></div>","PeriodicalId":55236,"journal":{"name":"Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology","volume":"283 ","pages":"Article 111204"},"PeriodicalIF":1.8,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146042318","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 : 2026-01-13DOI: 10.1016/j.cbpb.2026.111203
Chris N Glover, Alyssa M Weinrauch
{"title":"Understanding molecular and biochemical mechanisms are key to advances in applied dietary physiology.","authors":"Chris N Glover, Alyssa M Weinrauch","doi":"10.1016/j.cbpb.2026.111203","DOIUrl":"https://doi.org/10.1016/j.cbpb.2026.111203","url":null,"abstract":"","PeriodicalId":55236,"journal":{"name":"Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology","volume":" ","pages":"111203"},"PeriodicalIF":1.8,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145991833","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 : 2026-01-06DOI: 10.1016/j.cbpb.2026.111201
Xiudong Guo , Shucheng Zheng , Jiyuan Yin , Yingying Li , Yan Ren , Xubing Mo , Weiwei Zeng , Liping Zhang , Xidong Mu , Qing Wang , Yingying Wang
Hemorrhagic disease in grass carp (Ctenopharyngodon idella) caused by grass carp reovirus genotype II (GCRV-II) threatens sustainable aquaculture. To facilitate virus isolation, characterization, and studies on the pathogenic mechanisms of GCRV-II, we established a new cell line, Ctenopharyngodon idella trunk kidney (CITK). This cell line was developed using a trypsin digestion method and exhibited optimal proliferation at 27 °C in Medium 199/Leibovitz's L-15 medium supplemented with 10 % fetal bovine serum (FBS). Karyotype analysis revealed chromosome numbers of 2n = 48 and 2n = 60 at passages 10 (P10) and 60 (P60), respectively, indicating that the cell line underwent spontaneous immortalization during serial passaging. Species authentication (the mitochondrial cytochrome oxidase subunit I gene (cox1)), along with tissue-specific marker analysis, confirmed that CITK originated from the kidney tissue of grass carp. Mycoplasma testing confirmed the absence of contamination during cultivation. Functional assays demonstrated that CITK cells support efficient transfection with the green fluorescent protein gene plasmid. Notably, CITK exhibited significantly higher susceptibility to GCRV-II HN2407 compared to four other grass carp cell lines, with viral load reaching 6.26 × 105 copies/μL as determined by qRT-PCR. Kinetic analysis of infection revealed that, at 12, 24, and 48 h post-infection, GCRV-II induced time-dependent expression of key genes involved in innate immunity, pattern recognition receptors, signaling transducers, and adaptive immunity. The establishment of the immortalized CITK cell line provides a valuable platform for elucidating the pathogenic mechanisms of GCRV-II, developing antiviral strategies, and advancing studies on host-virus interactions in grass carp.
{"title":"Establishment of an immortalized renal epithelial cell line derived from grass carp and its susceptibility to grass carp Reovirus genotype II","authors":"Xiudong Guo , Shucheng Zheng , Jiyuan Yin , Yingying Li , Yan Ren , Xubing Mo , Weiwei Zeng , Liping Zhang , Xidong Mu , Qing Wang , Yingying Wang","doi":"10.1016/j.cbpb.2026.111201","DOIUrl":"10.1016/j.cbpb.2026.111201","url":null,"abstract":"<div><div>Hemorrhagic disease in grass carp (<em>Ctenopharyngodon idella</em>) caused by grass carp reovirus genotype II (GCRV-II) threatens sustainable aquaculture. To facilitate virus isolation, characterization, and studies on the pathogenic mechanisms of GCRV-II, we established a new cell line, <em>Ctenopharyngodon idella</em> trunk kidney (CITK). This cell line was developed using a trypsin digestion method and exhibited optimal proliferation at 27 °C in Medium 199/Leibovitz's L-15 medium supplemented with 10 % fetal bovine serum (FBS). Karyotype analysis revealed chromosome numbers of 2n = 48 and 2n = 60 at passages 10 (P10) and 60 (P60), respectively, indicating that the cell line underwent spontaneous immortalization during serial passaging. Species authentication (the mitochondrial cytochrome oxidase subunit I gene (<em>cox1</em>)), along with tissue-specific marker analysis, confirmed that CITK originated from the kidney tissue of grass carp. <em>Mycoplasma</em> testing confirmed the absence of contamination during cultivation. Functional assays demonstrated that CITK cells support efficient transfection with the green fluorescent protein gene plasmid. Notably, CITK exhibited significantly higher susceptibility to GCRV-II HN2407 compared to four other grass carp cell lines, with viral load reaching 6.26 × 10<sup>5</sup> copies/μL as determined by qRT-PCR. Kinetic analysis of infection revealed that, at 12, 24, and 48 h post-infection, GCRV-II induced time-dependent expression of key genes involved in innate immunity, pattern recognition receptors, signaling transducers, and adaptive immunity. The establishment of the immortalized CITK cell line provides a valuable platform for elucidating the pathogenic mechanisms of GCRV-II, developing antiviral strategies, and advancing studies on host-virus interactions in grass carp.</div></div>","PeriodicalId":55236,"journal":{"name":"Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology","volume":"283 ","pages":"Article 111201"},"PeriodicalIF":1.8,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928231","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 : 2026-01-05DOI: 10.1016/j.cbpb.2026.111200
Nguyen Van Thao , Andrea C. Alfaro , Nguyen Thao Suong , Le Viet Dung , Phan Nguyen Trang
Taurine, a β-amino sulfonic acid, is among the most abundant free amino acids in marine molluscs and functions as a dominant osmoprotectant critical for maintaining cellular homeostasis under fluctuating salinity. Beyond its osmoregulatory role, taurine exerts multifunctional cytoprotective, antioxidant, and immunomodulatory effects, positioning it as a key molecule in molluscan stress physiology. This commentary synthesises our current understanding of taurine dynamics in marine molluscs, highlighting recent advances in taurine transport, metabolism, and stress-responsive regulation. Particular attention is given to the taurine transporter (TauT) and its function in coordinating uptake and efflux during osmotic challenges, as well as the emerging evidence linking taurine to antioxidant defence and innate immunity. By integrating findings from molecular, biochemical, and cellular studies, this commentary underscores taurine as a multifunctional molecule fundamental to molluscan stress tolerance and identifies promising directions for future research, including omics-driven analyses of taurine regulatory pathways and their ecological relevance in rapidly changing marine ecosystems.
{"title":"Commentary: Taurine as a central osmoprotectant in marine molluscs – Roles in osmoregulation, oxidative balance and immune homeostasis","authors":"Nguyen Van Thao , Andrea C. Alfaro , Nguyen Thao Suong , Le Viet Dung , Phan Nguyen Trang","doi":"10.1016/j.cbpb.2026.111200","DOIUrl":"10.1016/j.cbpb.2026.111200","url":null,"abstract":"<div><div>Taurine, a β-amino sulfonic acid, is among the most abundant free amino acids in marine molluscs and functions as a dominant osmoprotectant critical for maintaining cellular homeostasis under fluctuating salinity. Beyond its osmoregulatory role, taurine exerts multifunctional cytoprotective, antioxidant, and immunomodulatory effects, positioning it as a key molecule in molluscan stress physiology. This commentary synthesises our current understanding of taurine dynamics in marine molluscs, highlighting recent advances in taurine transport, metabolism, and stress-responsive regulation. Particular attention is given to the taurine transporter (TauT) and its function in coordinating uptake and efflux during osmotic challenges, as well as the emerging evidence linking taurine to antioxidant defence and innate immunity. By integrating findings from molecular, biochemical, and cellular studies, this commentary underscores taurine as a multifunctional molecule fundamental to molluscan stress tolerance and identifies promising directions for future research, including omics-driven analyses of taurine regulatory pathways and their ecological relevance in rapidly changing marine ecosystems.</div></div>","PeriodicalId":55236,"journal":{"name":"Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology","volume":"283 ","pages":"Article 111200"},"PeriodicalIF":1.8,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145919100","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 : 2025-12-31DOI: 10.1016/j.cbpb.2025.111192
Danhong Cheng , Manjie Sun , Jinqian Huang , Shan Luo , Haotian Chen , Shengzhen Jin , Yanpeng Zhang , Xiaochen Yuan
In mammals, glucose-dependent insulinotropic polypeptide (GIP) exerts a potent hypoglycemic effect, whereas its role in fish remains controversial. In this study, synthetic grass carp GIP was administered via intraperitoneal injection, and its effects were evaluated over 24 h. GIP significantly elevated blood glucose levels at 0.5 h post-injection compared to the saline control. This hyperglycemia was accompanied by increased hepatic expression of the gluconeogenic genes glucose-6-phosphatase (g6pc) and phosphoenolpyruvate carboxykinase 1 (pck1) and decreased expression of the glycolytic gene pyruvate kinase (pk). Postprandial expression of the gip gene was also significantly upregulated in the foregut at 6 h. Furthermore, GIP administration modulated central appetite regulators within 1 h, increasing expression of the anorexigenic cocaine- and amphetamine-regulated transcript (cart) and decreasing expression of the orexigenic neuropeptide Y (npy) and agouti related neuropeptide (agrp). Collectively, these results indicate that in grass carp, GIP functions primarily as an appetite regulator rather than as a hypoglycemic incretin, highlighting its potential as a target for studies on appetite control in fish.
{"title":"Glucose-dependent insulinotropic polypeptide (GIP) acts as an appetite regulator rather than as a hypoglycemic incretin in grass carp","authors":"Danhong Cheng , Manjie Sun , Jinqian Huang , Shan Luo , Haotian Chen , Shengzhen Jin , Yanpeng Zhang , Xiaochen Yuan","doi":"10.1016/j.cbpb.2025.111192","DOIUrl":"10.1016/j.cbpb.2025.111192","url":null,"abstract":"<div><div>In mammals, glucose-dependent insulinotropic polypeptide (GIP) exerts a potent hypoglycemic effect, whereas its role in fish remains controversial. In this study, synthetic grass carp GIP was administered via intraperitoneal injection, and its effects were evaluated over 24 h. GIP significantly elevated blood glucose levels at 0.5 h post-injection compared to the saline control. This hyperglycemia was accompanied by increased hepatic expression of the gluconeogenic genes glucose-6-phosphatase (<em>g6pc</em>) and phosphoenolpyruvate carboxykinase 1 (<em>pck1</em>) and decreased expression of the glycolytic gene pyruvate kinase (<em>pk</em>). Postprandial expression of the <em>gip</em> gene was also significantly upregulated in the foregut at 6 h. Furthermore, GIP administration modulated central appetite regulators within 1 h, increasing expression of the anorexigenic cocaine- and amphetamine-regulated transcript (<em>cart</em>) and decreasing expression of the orexigenic neuropeptide Y (<em>npy)</em> and agouti related neuropeptide <em>(agrp</em>). Collectively, these results indicate that in grass carp, GIP functions primarily as an appetite regulator rather than as a hypoglycemic incretin, highlighting its potential as a target for studies on appetite control in fish.</div></div>","PeriodicalId":55236,"journal":{"name":"Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology","volume":"283 ","pages":"Article 111192"},"PeriodicalIF":1.8,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145891158","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 : 2025-12-20DOI: 10.1016/j.cbpb.2025.111191
Ayumi Nagashima, Akira Kato
Aquaglyceroporins are water channels that are permeable to uncharged, low-molecular-weight compounds such as glycerol. Aquaglyceroporins are conserved across many species. However, our knowledge of aquaglyceroporins in cartilaginous fish is limited, particularly regarding the functional differences in cartilaginous fish-specific paralogs. We analyzed the evolutionary relationship between Aqp10 paralogs in two elasmobranchs and one holocephalan and compared their solute permeabilities. Molecular phylogenetic and synteny analyses confirmed that the elasmobranch Aqp10 paralogs, Aqp10C1 and Aqp10C2, arose from a cartilaginous-fish-specific tandem gene duplication. The holocephalan lacks Aqp10C1 and possesses two paralogs (Aqp10C2a and Aqp10C2b) probably derived from Aqp10C2. Swelling assays showed that Aqp10C2 maintained glycerol permeability when expressed in Xenopus oocytes. However, the glycerol permeability of Aqp10C1s were lower than those of other paralogs and the activity was similar to those of water-specific aquaporins. Aqp10 function is highly differentiated in elasmobranchs, and Aqp10C1 may have lost its glycerol permeability during a unique evolution through tandem gene duplication and sub/neofunctionalization.
{"title":"Elasmobranch Aqp10 paralogs differ in glycerol permeability","authors":"Ayumi Nagashima, Akira Kato","doi":"10.1016/j.cbpb.2025.111191","DOIUrl":"10.1016/j.cbpb.2025.111191","url":null,"abstract":"<div><div>Aquaglyceroporins are water channels that are permeable to uncharged, low-molecular-weight compounds such as glycerol. Aquaglyceroporins are conserved across many species. However, our knowledge of aquaglyceroporins in cartilaginous fish is limited, particularly regarding the functional differences in cartilaginous fish-specific paralogs. We analyzed the evolutionary relationship between Aqp10 paralogs in two elasmobranchs and one holocephalan and compared their solute permeabilities. Molecular phylogenetic and synteny analyses confirmed that the elasmobranch Aqp10 paralogs, Aqp10C1 and Aqp10C2, arose from a cartilaginous-fish-specific tandem gene duplication. The holocephalan lacks Aqp10C1 and possesses two paralogs (Aqp10C2a and Aqp10C2b) probably derived from Aqp10C2. Swelling assays showed that Aqp10C2 maintained glycerol permeability when expressed in <em>Xenopus</em> oocytes. However, the glycerol permeability of Aqp10C1s were lower than those of other paralogs and the activity was similar to those of water-specific aquaporins. Aqp10 function is highly differentiated in elasmobranchs, and Aqp10C1 may have lost its glycerol permeability during a unique evolution through tandem gene duplication and sub/neofunctionalization.</div></div>","PeriodicalId":55236,"journal":{"name":"Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology","volume":"282 ","pages":"Article 111191"},"PeriodicalIF":1.8,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145812419","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 : 2025-12-18DOI: 10.1016/j.cbpb.2025.111190
Tessa S. Blanchard , Madison L. Earhart , Leah Campbell , Adam Harman , Ben Staples , Will Bugg , Patricia M. Schulte
Temperature varies in aquatic environments across many temporal scales, but relatively few studies have studied the effects of stable versus variable temperatures in fishes, particularly during early development. The goal of our study was to compare the lasting effects of varying extents of diel thermal fluctuation during embryonic development on whole-animal phenotypes and to examine underlying molecular mechanisms. To address this, we used Fundulus heteroclitus, a species of topminnow that inhabits intertidal saltmarshes along the Atlantic coast of North America that experience daily tidal fluctuations. We developed embryos under four different levels of diel thermal fluctuation (26 ± 0 °C, 26 ± 3 °C, 26 ± 5 °C, 26 ± 7 °C) from fertilization to hatch. Once hatched, larvae were raised at a common constant temperature of 26 °C for up to 6 months to test for lasting effects on phenotype due to developmental plasticity. We found evidence of developmental plasticity at our early sampling timepoints (1 and 3 months), as thermal tolerance (Critical thermal maximum (CTmax) and agitation temperature) and hypoxia tolerance decreased in response to fluctuating temperatures, whereas length was greater. By 6 months, length and metabolic rate did not differ between groups. Changes in physiological phenotypes were accompanied by altered mRNA levels of key regulatory genes such as insulin-like growth factors (igfs), heat-shock proteins (hsps), and hypoxia-inducible factor (hif1α). Together, these data demonstrate exposure to fluctuating temperature during early development has lasting effects for several months at both the physiological and molecular levels, which has implications for predicting the responses of fishes to climate change.
{"title":"Diel thermal fluctuations during embryonic development affect molecular and physiological phenotypes in later life stages of Fundulus heteroclitus","authors":"Tessa S. Blanchard , Madison L. Earhart , Leah Campbell , Adam Harman , Ben Staples , Will Bugg , Patricia M. Schulte","doi":"10.1016/j.cbpb.2025.111190","DOIUrl":"10.1016/j.cbpb.2025.111190","url":null,"abstract":"<div><div>Temperature varies in aquatic environments across many temporal scales, but relatively few studies have studied the effects of stable versus variable temperatures in fishes, particularly during early development. The goal of our study was to compare the lasting effects of varying extents of diel thermal fluctuation during embryonic development on whole-animal phenotypes and to examine underlying molecular mechanisms. To address this, we used <em>Fundulus heteroclitus</em>, a species of topminnow that inhabits intertidal saltmarshes along the Atlantic coast of North America that experience daily tidal fluctuations. We developed embryos under four different levels of diel thermal fluctuation (26 ± 0 °C, 26 ± 3 °C, 26 ± 5 °C, 26 ± 7 °C) from fertilization to hatch. Once hatched, larvae were raised at a common constant temperature of 26 °C for up to 6 months to test for lasting effects on phenotype due to developmental plasticity. We found evidence of developmental plasticity at our early sampling timepoints (1 and 3 months), as thermal tolerance (Critical thermal maximum (CT<sub>max</sub>) and agitation temperature) and hypoxia tolerance decreased in response to fluctuating temperatures, whereas length was greater. By 6 months, length and metabolic rate did not differ between groups. Changes in physiological phenotypes were accompanied by altered mRNA levels of key regulatory genes such as insulin-like growth factors <em>(igfs),</em> heat-shock proteins <em>(hsps),</em> and hypoxia-inducible factor (<em>hif1α)</em>. Together, these data demonstrate exposure to fluctuating temperature during early development has lasting effects for several months at both the physiological and molecular levels, which has implications for predicting the responses of fishes to climate change.</div></div>","PeriodicalId":55236,"journal":{"name":"Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology","volume":"283 ","pages":"Article 111190"},"PeriodicalIF":1.8,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145800876","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 : 2025-12-15DOI: 10.1016/j.cbpb.2025.111189
Peizhen Ma , Shuangli Zhang , Xiangyu Wu , Shaojing Yan , Chenxia Zuo , Zhen Zhang
Siphonariid limpets are a group of intertidal pulmonate snails that have undergone aquatic-terrestrial evolution followed by secondary recolonization of the marine environment. To elucidate the responses of Siphonaria japonica to extended aerial exposure and seawater immersion, we conducted comparative transcriptome analysis of three tissues (foot, gill, and mantle) using both next-generation RNA sequencing (RNA-seq) and full-length isoform sequencing (Iso-seq) methods. For Iso-seq, 448,457 reads representing a total length of 14,622,086 bp were obtained, which were assembled into 8072 unigenes. For RNA-seq, 867,101,624 clean reads were obtained with a total length of 130,390,993,290 bp. The Iso-seq and RNA-seq data were integrated to construct a comprehensive gene annotation across three tissues. Results showed that gill displayed the most extensive response with 252 differentially expressed genes (DEGs), whereas mantle exhibited the least with 121 DEGs. Gene Ontology enrichment analysis showed that the gill, mantle, and foot exhibited distinct gene regulatory profiles. The gill was involved in osmoregulatory and cell adhesion pathways, the mantle was implicated in metabolic processes, whereas in the foot transcripts associated with pathways related to epidermal cell differentiation, as well as serine-type endopeptidase inhibitor activity were prominent. Collectively, these findings suggest that S. japonica mounted a coordinated multi-tissue response, integrating metabolic modulation, osmoregulatory fine-tuning, and structural remodeling to optimize energy allocation under aquatic and terrestrial conditions.
{"title":"Aerial exposure and seawater immersion induce distinct transcriptomic responses of the marine pulmonate gastropod, Siphonaria japonica (Donovan, 1824), as determined by Iso-seq and RNA-seq analysis","authors":"Peizhen Ma , Shuangli Zhang , Xiangyu Wu , Shaojing Yan , Chenxia Zuo , Zhen Zhang","doi":"10.1016/j.cbpb.2025.111189","DOIUrl":"10.1016/j.cbpb.2025.111189","url":null,"abstract":"<div><div>Siphonariid limpets are a group of intertidal pulmonate snails that have undergone aquatic-terrestrial evolution followed by secondary recolonization of the marine environment. To elucidate the responses of <em>Siphonaria japonica</em> to extended aerial exposure and seawater immersion, we conducted comparative transcriptome analysis of three tissues (foot, gill, and mantle) using both next-generation RNA sequencing (RNA-seq) and full-length isoform sequencing (Iso-seq) methods. For Iso-seq, 448,457 reads representing a total length of 14,622,086 bp were obtained, which were assembled into 8072 unigenes. For RNA-seq, 867,101,624 clean reads were obtained with a total length of 130,390,993,290 bp. The Iso-seq and RNA-seq data were integrated to construct a comprehensive gene annotation across three tissues. Results showed that gill displayed the most extensive response with 252 differentially expressed genes (DEGs), whereas mantle exhibited the least with 121 DEGs. Gene Ontology enrichment analysis showed that the gill, mantle, and foot exhibited distinct gene regulatory profiles. The gill was involved in osmoregulatory and cell adhesion pathways, the mantle was implicated in metabolic processes, whereas in the foot transcripts associated with pathways related to epidermal cell differentiation, as well as serine-type endopeptidase inhibitor activity were prominent. Collectively, these findings suggest that <em>S. japonica</em> mounted a coordinated multi-tissue response, integrating metabolic modulation, osmoregulatory fine-tuning, and structural remodeling to optimize energy allocation under aquatic and terrestrial conditions.</div></div>","PeriodicalId":55236,"journal":{"name":"Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology","volume":"282 ","pages":"Article 111189"},"PeriodicalIF":1.8,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145776575","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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