Pub Date : 2026-01-22DOI: 10.1016/j.fsi.2026.111151
Yilin Zhang , Fan Wu , Kevin WH. Kwok , Yiming Wen , Zhen Gan , Yishan Lu
As key bacterial signaling mechanisms, two-component systems (TCSs) regulate numerous cellular processes, with the BarA/UvrY system particularly important for controlling stress adaptation and virulence. However, the functions of BarA/UvrY in Vibrio harveyi, a major vibriosis-causing pathogen in marine fish, are still unclear. In this study, we analyzed the V. harveyi typical phenotypic alterations following barA and uvrY deletion, and the result indicated that deletion of barA and uvrY decreased maximum growth density and motility, and increased the susceptibility to pH stress, iron limitation, and antibiotics in V. harveyi. Besides, the biofilm formation pattern is a time-dependent process in V. harveyi. In addition, deletion of barA and uvrY reduced bacterial adhesion, intracellular ferrous ion concentration, while also increasing apoptosis and viability in host cell. Furthermore, the mutation impaired the ability of the bacteria to invade and replicate within primary grouper macrophages. Lastly, immunization with ΔbarA and ΔuvrY stimulated host immune responses through upregulation of immune-related genes and increased serum enzyme activity, providing substantial protection against V. harveyi infection in grouper. These results provide crucial insights into BarA/UvrY regulatory system of γ-proteobacteria and reveal novel aspects of pathogenic strategies employed in marine fish hosts.
{"title":"The roles of the BarA-UvrY two-component system in the virulence of Vibrio harveyi and the efficacy evaluation of mutant strains ΔbarA and ΔuvrY as live-attenuated vaccines","authors":"Yilin Zhang , Fan Wu , Kevin WH. Kwok , Yiming Wen , Zhen Gan , Yishan Lu","doi":"10.1016/j.fsi.2026.111151","DOIUrl":"10.1016/j.fsi.2026.111151","url":null,"abstract":"<div><div>As key bacterial signaling mechanisms, two-component systems (TCSs) regulate numerous cellular processes, with the BarA/UvrY system particularly important for controlling stress adaptation and virulence. However, the functions of BarA/UvrY in <em>Vibrio harveyi</em>, a major vibriosis-causing pathogen in marine fish, are still unclear. In this study, we analyzed the <em>V. harveyi</em> typical phenotypic alterations following <em>barA</em> and <em>uvrY</em> deletion, and the result indicated that deletion of <em>barA</em> and <em>uvrY</em> decreased maximum growth density and motility, and increased the susceptibility to pH stress, iron limitation, and antibiotics in <em>V. harveyi</em>. Besides, the biofilm formation pattern is a time-dependent process in <em>V. harveyi</em>. In addition, deletion of <em>barA</em> and <em>uvrY</em> reduced bacterial adhesion, intracellular ferrous ion concentration, while also increasing apoptosis and viability in host cell. Furthermore, the mutation impaired the ability of the bacteria to invade and replicate within primary grouper macrophages. Lastly, immunization with <em>ΔbarA</em> and <em>ΔuvrY</em> stimulated host immune responses through upregulation of immune-related genes and increased serum enzyme activity, providing substantial protection against <em>V. harveyi</em> infection in grouper. These results provide crucial insights into BarA/UvrY regulatory system of γ-proteobacteria and reveal novel aspects of pathogenic strategies employed in marine fish hosts.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"171 ","pages":"Article 111151"},"PeriodicalIF":3.9,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146043820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-22DOI: 10.1016/j.fsi.2026.111152
Yuqing Zeng , Yuhao Jin , Xiaoyu Gu , Yifan Gu , Yiqing Wang , Mengjia Chen , Xue Qiao , Lingling Wang , Linsheng Song
The 2′,5′-oligoadenylate synthetases like (OASL) is a representative member of interferon-stimulated genes (ISGs), which plays a critical role in the innate immune defense against viral infections by sensing dsRNA and assisting RIG-I-like receptors (RLR) mediated antiviral signal. In the present study, an OASL homologue (named CgOASL) with a conserved OAS1_C domain was identified in the Pacific oyster Crassostrea gigas. The mRNA transcripts of CgOASL were widely detected in all the tested tissues with the highest expression level in adductor muscle. The mRNA expression level of CgOASL in haemocytes was significantly upregulated after poly (I:C) and recombinant IFN-like protein (rCgIFNLP) stimulation. After RNAi of CgIFNLP and its receptor CgIFNR-3, the mRNA expression of CgOASL was significantly down-regulated compared to control group after poly (I:C) stimulation. And the recombinant CgOASL (rCgOASL) showed strong in vitro binding affinity for dsRNA. Upon co-transfection of CgOASL and RIG-I-like receptors (RLR) member (CgRIG-I and CgMDA5), the Co-IP assays revealed a specific interaction of CgOASL with CgMDA5, but not with CgRIG-I, which is consistent with the activities of vertebrate OASL proteins. This interaction was further confirmed by pull-down experiments. And transfection of CgOASL also significantly induced the ISG expression in HEK293T cells. Taken together, CgOASL was an ISG regulated by CgIFNLP, capable of recognizing dsRNA and interacting with CgMDA5 to exert antiviral activity. These findings highlight its potential role in oyster antiviral innate immunity and offer new insights into the functional evolution of OASL proteins in invertebrates.
{"title":"An OASL homologue involved in IFN-like antiviral signal by binding MDA5 in the Pacific oyster Crassostrea gigas","authors":"Yuqing Zeng , Yuhao Jin , Xiaoyu Gu , Yifan Gu , Yiqing Wang , Mengjia Chen , Xue Qiao , Lingling Wang , Linsheng Song","doi":"10.1016/j.fsi.2026.111152","DOIUrl":"10.1016/j.fsi.2026.111152","url":null,"abstract":"<div><div>The 2′,5′-oligoadenylate synthetases like (OASL) is a representative member of interferon-stimulated genes (ISGs), which plays a critical role in the innate immune defense against viral infections by sensing dsRNA and assisting RIG-I-like receptors (RLR) mediated antiviral signal. In the present study, an OASL homologue (named <em>Cg</em>OASL) with a conserved OAS1_C domain was identified in the Pacific oyster <em>Crassostrea gigas</em>. The mRNA transcripts of <em>Cg</em>OASL were widely detected in all the tested tissues with the highest expression level in adductor muscle. The mRNA expression level of <em>Cg</em>OASL in haemocytes was significantly upregulated after poly (I:C) and recombinant IFN-like protein (r<em>Cg</em>IFNLP) stimulation. After RNAi of <em>Cg</em>IFNLP and its receptor <em>Cg</em>IFNR-3, the mRNA expression of <em>Cg</em>OASL was significantly down-regulated compared to control group after poly (I:C) stimulation. And the recombinant <em>Cg</em>OASL (r<em>Cg</em>OASL) showed strong <em>in vitro</em> binding affinity for dsRNA. Upon co-transfection of <em>Cg</em>OASL and RIG-I-like receptors (RLR) member (<em>Cg</em>RIG-I and <em>Cg</em>MDA5), the Co-IP assays revealed a specific interaction of <em>Cg</em>OASL with <em>Cg</em>MDA5, but not with <em>Cg</em>RIG-I, which is consistent with the activities of vertebrate OASL proteins. This interaction was further confirmed by pull-down experiments. And transfection of <em>Cg</em>OASL also significantly induced the ISG expression in HEK293T cells. Taken together, <em>Cg</em>OASL was an ISG regulated by <em>Cg</em>IFNLP, capable of recognizing dsRNA and interacting with <em>Cg</em>MDA5 to exert antiviral activity. These findings highlight its potential role in oyster antiviral innate immunity and offer new insights into the functional evolution of OASL proteins in invertebrates.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"171 ","pages":"Article 111152"},"PeriodicalIF":3.9,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146043599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-22DOI: 10.1016/j.fsi.2026.111143
Yibo Jia , Lu Cao , Tongyao Li , Haiyan Zhao , Gen Chen , Zijun Xiong , Weiya Rong , Qing Liu , Weiwei Wang , Jing Song , Xianzong Wang , Yu Liu , Shao-Zhen Liu
This study investigated the individual and combined effects of Polystyrene microplastics (PS) and 17α-methyltestosterone (MT) on the gill and liver of Gobiocypris rarus.Exposure to PS (0.5 mg/L) and MT (50 ng/L) induced significant histopathological alterations and immunotoxicity. Tissues exhibited inflammatory infiltration, nuclear dissolution, and cytoplasmic vacuolation, with the most severe lesions observed under combined exposure. Gene expression analysis revealed significant upregulation of immune and oxidative stress-related genes, including caspase 6 (CASP6), interleukin-1 receptor type I (IL-1RI), NADPH oxidase 1 (NOX1), Toll-like receptor 2 (TLR-2), and C-C motif chemokine receptor 7 (CCR7), while antioxidant enzyme activities and malondialdehyde (MDA) levels were disrupted, indicating enhanced oxidative stress. Transcriptomic analysis of gills further revealed enrichment of ECM-receptor interaction, cell adhesion molecules, and leukocyte transendothelial migration pathways, suggesting that PS and MT may compromise immune function by interfering with extracellular matrix-related signaling, thereby exacerbating tissue damage and posing combined ecological risks in aquatic organisms.
{"title":"Synergistic effects of polystyrene microplastics and 17α-methyltestosterone on immune and oxidative stress responses in the gill and liver of Gobiocypris rarus","authors":"Yibo Jia , Lu Cao , Tongyao Li , Haiyan Zhao , Gen Chen , Zijun Xiong , Weiya Rong , Qing Liu , Weiwei Wang , Jing Song , Xianzong Wang , Yu Liu , Shao-Zhen Liu","doi":"10.1016/j.fsi.2026.111143","DOIUrl":"10.1016/j.fsi.2026.111143","url":null,"abstract":"<div><div>This study investigated the individual and combined effects of Polystyrene microplastics (PS) and 17α-methyltestosterone (MT) on the gill and liver of <em>Gobiocypris rarus</em>.Exposure to PS (0.5 mg/L) and MT (50 ng/L) induced significant histopathological alterations and immunotoxicity. Tissues exhibited inflammatory infiltration, nuclear dissolution, and cytoplasmic vacuolation, with the most severe lesions observed under combined exposure. Gene expression analysis revealed significant upregulation of immune and oxidative stress-related genes, including caspase 6 (<em>CASP6</em>), interleukin-1 receptor type I (<em>IL-1RI</em>), NADPH oxidase 1 (<em>NOX1</em>), Toll-like receptor 2 (<em>TLR-2</em>), and C-C motif chemokine receptor 7 (<em>CCR7</em>), while antioxidant enzyme activities and malondialdehyde (MDA) levels were disrupted, indicating enhanced oxidative stress. Transcriptomic analysis of gills further revealed enrichment of ECM-receptor interaction, cell adhesion molecules, and leukocyte transendothelial migration pathways, suggesting that PS and MT may compromise immune function by interfering with extracellular matrix-related signaling, thereby exacerbating tissue damage and posing combined ecological risks in aquatic organisms.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"171 ","pages":"Article 111143"},"PeriodicalIF":3.9,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146043532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","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.fsi.2026.111145
Bo Tang , Gaofeng Cheng , Yizhong Lu , Wenxing Li , Yuezong Xu , Chunrong Yang , Zhen Xu , Weiguang Kong , Jianguo Su
Grass carp reovirus (GCRV) poses a serious economic threat to grass carp aquaculture and oral vaccination has become the strategy of choice for its control. In this study, multiple sequence alignment was conducted on the sequences of the VP56 of seven GCRV-II strains. The most frequent amino acid at each site was assigned to the fusion sequence to obtain the sequences of GCRV-FUSION (VP561-512). Through antigenic index analysis, the full-length sequence (VP561-512) was truncated, thereby obtaining five truncated antigen fragments: VP561-210, VP56100-209, VP56210-310, VP56310-500, and VP56410-500. Then, using flagellin C (FlaC) from Aeromonas hydrophila as an adjuvant, recombinant Pichia pastoris expressing VP561-512-FlaC, VP561-210-FlaC, VP56100-209-FlaC, VP56210-310-FlaC, VP56310-500-FlaC and VP56410-500-FlaC were constructed, and recombinant proteins were examined by SDS-PAGE and WB assays. The experimental fish was divided into 8 groups (blank control, P-pPIC3.5K, P-VP561-512-FlaC, P-VP561-210-FlaC, P-VP56100-209-FlaC, P-VP56210-310-FlaC, P-VP56310-500-FlaC, P-VP56410-500-FlaC) to evaluate the protective effect. The survival rate of the P-VP56310-500-FlaC group (54 %) was significantly higher than that of the blank control group (18 %). Oral P-VP56310-500-FlaC vaccine can effectively increase serum enzyme activities (lysozyme, total antioxidant capacity and complement component 3). The mRNA expressions of immune genes (TLR5a, IL-6, IFN1, Mx2, IL-1β, MHCII, IgM, IgT) in the P-VP56310-500-FlaC group were significantly increased. The vaccine P-VP56310-500-FlaC significantly inhibited the replication of GCRV in the spleen, head kidney and midgut, and reduced the degree of damage to the spleen. The above results indicate that oral P-VP56310-500-FlaC vaccine can effectively control GCRV infection, providing an effective strategy for the prevention of viral diseases in aquaculture.
{"title":"An oral multivalent fusion vaccine based on antigenic fragment VP56310-500 and FlaC adjuvant confers effective protection against grass carp reovirus","authors":"Bo Tang , Gaofeng Cheng , Yizhong Lu , Wenxing Li , Yuezong Xu , Chunrong Yang , Zhen Xu , Weiguang Kong , Jianguo Su","doi":"10.1016/j.fsi.2026.111145","DOIUrl":"10.1016/j.fsi.2026.111145","url":null,"abstract":"<div><div>Grass carp reovirus (GCRV) poses a serious economic threat to grass carp aquaculture and oral vaccination has become the strategy of choice for its control. In this study, multiple sequence alignment was conducted on the sequences of the VP56 of seven GCRV-II strains. The most frequent amino acid at each site was assigned to the fusion sequence to obtain the sequences of GCRV-FUSION (VP56<sub>1-512</sub>). Through antigenic index analysis, the full-length sequence (VP56<sub>1-512</sub>) was truncated, thereby obtaining five truncated antigen fragments: VP56<sub>1-210</sub>, VP56<sub>100-209</sub>, VP56<sub>210-310</sub>, VP56<sub>310-500</sub>, and VP56<sub>410-500</sub>. Then, using flagellin C (FlaC) from <em>Aeromonas hydrophila</em> as an adjuvant, recombinant <em>Pichia pastoris</em> expressing VP56<sub>1-512</sub>-FlaC, VP56<sub>1-210</sub>-FlaC, VP56<sub>100-209</sub>-FlaC, VP56<sub>210-310</sub>-FlaC, VP56<sub>310-500</sub>-FlaC and VP56<sub>410-500</sub>-FlaC were constructed, and recombinant proteins were examined by SDS-PAGE and WB assays. The experimental fish was divided into 8 groups (blank control, <em>P</em>-pPIC3.5K, <em>P</em>-VP56<sub>1-512</sub>-FlaC, <em>P</em>-VP56<sub>1-210</sub>-FlaC, <em>P</em>-VP56<sub>100-209</sub>-FlaC, <em>P</em>-VP56<sub>210-310</sub>-FlaC, <em>P</em>-VP56<sub>310-500</sub>-FlaC, <em>P</em>-VP56<sub>410-500</sub>-FlaC) to evaluate the protective effect. The survival rate of the <em>P</em>-VP56<sub>310-500</sub>-FlaC group (54 %) was significantly higher than that of the blank control group (18 %). Oral <em>P</em>-VP56<sub>310-500</sub>-FlaC vaccine can effectively increase serum enzyme activities (lysozyme, total antioxidant capacity and complement component 3). The mRNA expressions of immune genes (<em>TLR5a, IL-6, IFN1, Mx2, IL-1β, MHCII, IgM, IgT</em>) in the <em>P</em>-VP56<sub>310-500</sub>-FlaC group were significantly increased. The vaccine <em>P</em>-VP56<sub>310-500</sub>-FlaC significantly inhibited the replication of GCRV in the spleen, head kidney and midgut, and reduced the degree of damage to the spleen. The above results indicate that oral <em>P</em>-VP56<sub>310-500</sub>-FlaC vaccine can effectively control GCRV infection, providing an effective strategy for the prevention of viral diseases in aquaculture.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111145"},"PeriodicalIF":3.9,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146028922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","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.fsi.2026.111146
Andre Giovanni , Yin-Ze Shi , Pei-Chi Wang , Ming-An Tsai , Shih-Chu Chen
Streptococcus iniae is a highly virulent pathogen causing severe streptococcosis outbreaks and high mortality in cultured fish, including four-finger threadfin fish in Taiwan. This study evaluated the immunogenicity and protective efficacy of recombinant enolase, surface immunogenic protein (SIP), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), administered individually and in combination, as subunit vaccines against S. iniae infection. Recombinant proteins were expressed in Escherichia coli, purified, and emulsified in an oil-based adjuvant before intraperitoneal vaccination of threadfin fish. Immune responses were assessed through serum IgM levels, lysozyme activity, immune gene expression, serum bactericidal activity, and relative percent survival (RPS) after challenge with virulent S. iniae. The results demonstrated successful expression of target proteins and significant elevation of antigen-specific IgM antibody level, particularly in the combination vaccine group. Enhanced lysozyme activity and upregulation of complement component C2, T cell marker CD8, and cytokines (TNF-α, IL-12, IL-10) indicated robust innate and adaptive immune activation. Serum bactericidal assays revealed the highest bacterial killing in fish vaccinated with the combination formulation. Post-challenge survival was greatest in fish receiving formalin-killed cell vaccine (RPS 86.2 %), followed by moderate protection conferred by recombinant SIP (rSIP) (72.4 %) and the combination vaccine (52.7 %). Recombinant enolase and GAPDH provided lower protection levels. These findings highlight the potential of rSIP and multivalent subunit vaccines as promising strategies for controlling S. iniae infections in aquaculture.
{"title":"Evaluation of recombinant SIP, enolase, and GAPDH as subunit vaccine candidates against Streptococcus iniae in four-finger threadfin (Eleutheronema tetradactylum): Immunogenicity, protective efficacy, and multivalent potential","authors":"Andre Giovanni , Yin-Ze Shi , Pei-Chi Wang , Ming-An Tsai , Shih-Chu Chen","doi":"10.1016/j.fsi.2026.111146","DOIUrl":"10.1016/j.fsi.2026.111146","url":null,"abstract":"<div><div><em>Streptococcus iniae</em> is a highly virulent pathogen causing severe streptococcosis outbreaks and high mortality in cultured fish, including four-finger threadfin fish in Taiwan. This study evaluated the immunogenicity and protective efficacy of recombinant enolase, surface immunogenic protein (SIP), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), administered individually and in combination, as subunit vaccines against <em>S. iniae</em> infection. Recombinant proteins were expressed in <em>Escherichia coli</em>, purified, and emulsified in an oil-based adjuvant before intraperitoneal vaccination of threadfin fish. Immune responses were assessed through serum IgM levels, lysozyme activity, immune gene expression, serum bactericidal activity, and relative percent survival (RPS) after challenge with virulent <em>S. iniae</em>. The results demonstrated successful expression of target proteins and significant elevation of antigen-specific IgM antibody level, particularly in the combination vaccine group. Enhanced lysozyme activity and upregulation of complement component C2, T cell marker CD8, and cytokines (TNF-α, IL-12, IL-10) indicated robust innate and adaptive immune activation. Serum bactericidal assays revealed the highest bacterial killing in fish vaccinated with the combination formulation. Post-challenge survival was greatest in fish receiving formalin-killed cell vaccine (RPS 86.2 %), followed by moderate protection conferred by recombinant SIP (<em>r</em>SIP) (72.4 %) and the combination vaccine (52.7 %). Recombinant enolase and GAPDH provided lower protection levels. These findings highlight the potential of <em>r</em>SIP and multivalent subunit vaccines as promising strategies for controlling <em>S. iniae</em> infections in aquaculture.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111146"},"PeriodicalIF":3.9,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146040780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","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.fsi.2026.111150
Seok-Ju Lee , Su-Mi Shin , Jae-Hyun Sim , Da-Jeong Yoo , Eunju Kim , Myung-Hwa Jung
Water temperature profoundly shapes the physiology and immunity of poikilothermic fish, yet gradual thermal transitions remain poorly characterized. This study examined hematological, biochemical, and gene-expression responses derived entirely from whole blood of black seabream (Acanthopagrus schlegelii) exposed to progressive warming (30 °C) and cooling (8 °C). Short-term thermal response proceeded through reversible phases of activation, remodeling, and stabilization as reflected in hematological, biochemical, and molecular indices. Moderate cooling (20–18 °C) induced the most dynamic reorganization, including transient increases in monocytes and granulocytes, elevated alanine aminotransferase activity, and lipid depletion indicating early innate immune deployment and metabolic redistribution preceding deep cold suppression. Several hematological parameters exhibited nonlinear, compensatory trends: mean corpuscular hemoglobin concentration (MCHC) increased under cold exposure, whereas red cell distribution width (RDW) expanded at both thermal extremes, revealing alternative strategies for maintaining oxygen transport and erythrocyte stability. Gene expression showed selective and pathway-specific regulation, with interleukin1beta (IL1β) up-regulated at both water temperature extremes, heat shock protein 90 (HSP90) elevated under heat stress, and glutathione peroxidase 1 (GPX1) down-regulated under cold exposure, reflecting flexible and individualized physiological adjustments. Taken together, these findings establish a blood-centered model of short-term thermal response, in which whole-blood physiology functions as a regulatory hub integrating oxygen transport, immune modulation, and metabolic balance. These findings highlight blood parameters as sensitive, non-invasive biomarkers of short-term thermal response, particularly revealing a previously underappreciated moderate-cooling phase that drives immune and metabolic reorganization.
水温深刻地塑造了变热鱼类的生理和免疫，但逐渐的热转变仍然很不清楚。本研究检测了暴露于逐渐升温（30°C）和冷却（8°C）的黑海鲷（棘海鲷）全血的血液学、生化和基因表达反应。短期热反应经历了激活、重塑和稳定的可逆阶段，这反映在血液学、生化和分子指标上。适度冷却（20-18°C）诱导了最动态的重组，包括单核细胞和粒细胞的短暂增加，丙氨酸转氨酶活性升高，脂质消耗表明在深度冷抑制之前早期先天免疫部署和代谢重新分配。几个血液学参数表现出非线性的补偿趋势：平均红细胞血红蛋白浓度（MCHC）在冷暴露下增加，而红细胞分布宽度（RDW）在两个极端温度下都扩大，揭示了维持氧运输和红细胞稳定性的替代策略。基因表达表现出选择性和途径特异性调控，白介素1β (il - 1β)在两种极端水温条件下均上调，热休克蛋白90 （HSP90）在热应激条件下升高，谷胱甘肽过氧化物酶1 （GPX1）在冷暴露条件下下调，反映出灵活和个性化的生理调节。综上所述，这些发现建立了一个以血液为中心的短期热反应模型，其中全血生理学作为一个整合氧运输、免疫调节和代谢平衡的调节枢纽。这些发现强调了血液参数是短期热反应的敏感、非侵入性生物标志物，特别是揭示了以前未被重视的驱动免疫和代谢重组的中度冷却阶段。
{"title":"Hematology-centered physiological remodeling of black seabream (Acanthopagrus schlegelii) under gradual water temperature fluctuations","authors":"Seok-Ju Lee , Su-Mi Shin , Jae-Hyun Sim , Da-Jeong Yoo , Eunju Kim , Myung-Hwa Jung","doi":"10.1016/j.fsi.2026.111150","DOIUrl":"10.1016/j.fsi.2026.111150","url":null,"abstract":"<div><div>Water temperature profoundly shapes the physiology and immunity of poikilothermic fish, yet gradual thermal transitions remain poorly characterized. This study examined hematological, biochemical, and gene-expression responses derived entirely from whole blood of black seabream (<em>Acanthopagrus schlegelii</em>) exposed to progressive warming (30 °C) and cooling (8 °C). Short-term thermal response proceeded through reversible phases of activation, remodeling, and stabilization as reflected in hematological, biochemical, and molecular indices. Moderate cooling (20–18 °C) induced the most dynamic reorganization, including transient increases in monocytes and granulocytes, elevated alanine aminotransferase activity, and lipid depletion indicating early innate immune deployment and metabolic redistribution preceding deep cold suppression. Several hematological parameters exhibited nonlinear, compensatory trends: mean corpuscular hemoglobin concentration (MCHC) increased under cold exposure, whereas red cell distribution width (RDW) expanded at both thermal extremes, revealing alternative strategies for maintaining oxygen transport and erythrocyte stability. Gene expression showed selective and pathway-specific regulation, with <em>interleukin1beta (IL1β)</em> up-regulated at both water temperature extremes, <em>heat shock protein 90</em> (<em>HSP90</em>) elevated under heat stress, and <em>glutathione peroxidase 1</em> (<em>GPX1</em>) down-regulated under cold exposure, reflecting flexible and individualized physiological adjustments. Taken together, these findings establish a blood-centered model of short-term thermal response, in which whole-blood physiology functions as a regulatory hub integrating oxygen transport, immune modulation, and metabolic balance. These findings highlight blood parameters as sensitive, non-invasive biomarkers of short-term thermal response, particularly revealing a previously underappreciated moderate-cooling phase that drives immune and metabolic reorganization.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111150"},"PeriodicalIF":3.9,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-20DOI: 10.1016/j.fsi.2026.111139
Young-Bin Yu , A-Hyun Jo , Cheol Young Choi , Ju-Chan Kang , Jun-Hwan Kim
Crucian carp (Carassius carassius) were exposed to polyethylene microplastics (PE-MPs) at concentrations of 0, 4, 8, 16, 32, and 64 mg/L for two weeks. The experimental fish had a mean weight of 23.2 ± 3.1 g and a mean length of 12.1 ± 0.9 cm. Exposure to ≥32 mg/L PE-MPs caused significant increases in cortisol and HSP70 levels, indicating activation of endocrine and cellular stress responses. In contrast, immune parameters such as lysozyme activity and IgM concentrations were significantly reduced, demonstrating suppression of both innate and adaptive immune functions. Moreover, acetylcholinesterase (AChE) activity was significantly inhibited, reflecting impaired cholinergic neurotransmission and neurotoxicity. Integrated biomarker response (IBR) analysis revealed concentration-dependent alterations, while heatmap and principal component analyses (PCA) confirmed that PE-MPs predominantly induced stress-related physiological responses. Collectively, these findings demonstrate that exposure to ≥32 mg/L PE-MPs poses significant physiological and neuro-immunotoxic risks to C. carassius.
{"title":"Toxic effects of microplastic (polyethylene) exposure: Stress, immune responses and neurotoxicity in crucian carp, Carassius carassius","authors":"Young-Bin Yu , A-Hyun Jo , Cheol Young Choi , Ju-Chan Kang , Jun-Hwan Kim","doi":"10.1016/j.fsi.2026.111139","DOIUrl":"10.1016/j.fsi.2026.111139","url":null,"abstract":"<div><div>Crucian carp (<em>Carassius carassius</em>) were exposed to polyethylene microplastics (PE-MPs) at concentrations of 0, 4, 8, 16, 32, and 64 mg/L for two weeks. The experimental fish had a mean weight of 23.2 ± 3.1 g and a mean length of 12.1 ± 0.9 cm. Exposure to ≥32 mg/L PE-MPs caused significant increases in cortisol and HSP70 levels, indicating activation of endocrine and cellular stress responses. In contrast, immune parameters such as lysozyme activity and IgM concentrations were significantly reduced, demonstrating suppression of both innate and adaptive immune functions. Moreover, acetylcholinesterase (AChE) activity was significantly inhibited, reflecting impaired cholinergic neurotransmission and neurotoxicity. Integrated biomarker response (IBR) analysis revealed concentration-dependent alterations, while heatmap and principal component analyses (PCA) confirmed that PE-MPs predominantly induced stress-related physiological responses. Collectively, these findings demonstrate that exposure to ≥32 mg/L PE-MPs poses significant physiological and neuro-immunotoxic risks to <em>C. carassius</em>.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111139"},"PeriodicalIF":3.9,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146028937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-20DOI: 10.1016/j.fsi.2026.111134
Yuan Feng , Wenxing Li , Jiamei Liu , Huazhi Chen , Pan Qin , Jingqun Ao , Xinhua Chen
Midnolin has recently been shown to mediate ubiquitin-independent proteasomal degradation of nuclear substrates, yet its evolutionary origin and function in non-mammalian immunity remain largely unexplored. Here, we identify a Midnolin homolog in large yellow croaker (Larimichthys crocea). A key finding is that the origin of Midnolin can be traced back to placozoans, the simplest known animals whose emergence predates that of sponges. In L. crocea, Lcmidnolin expression was significantly upregulated in immune-related tissues upon stimulation with poly(I:C), a viral mimic, suggesting its responsiveness to viral-like signals. Confocal microscopy revealed nuclear localization of LcMidnolin. Functionally, overexpression of LcMidnolin suppressed poly(I:C)-induced activation of type I interferon (IFN) promoters and diminished antiviral gene expression. Consistent with this inhibitory effect, LcMidnolin overexpression impaired the cellular antiviral response, as reflected by increased viral gene expression and exacerbated cytopathic effects in cells infected with spring viremia of carp virus (SVCV). Our findings provide the first evolutionary and functional insights into Midnolin in a non-mammalian vertebrate, revealing its previously unrecognized role as a regulator of the type I IFN signaling pathway.
{"title":"Midnolin has an ancient origin and negatively regulates type I IFN response in teleost fish","authors":"Yuan Feng , Wenxing Li , Jiamei Liu , Huazhi Chen , Pan Qin , Jingqun Ao , Xinhua Chen","doi":"10.1016/j.fsi.2026.111134","DOIUrl":"10.1016/j.fsi.2026.111134","url":null,"abstract":"<div><div>Midnolin has recently been shown to mediate ubiquitin-independent proteasomal degradation of nuclear substrates, yet its evolutionary origin and function in non-mammalian immunity remain largely unexplored. Here, we identify a Midnolin homolog in large yellow croaker (<em>Larimichthys crocea</em>). A key finding is that the origin of Midnolin can be traced back to placozoans, the simplest known animals whose emergence predates that of sponges. In <em>L. crocea</em>, <em>Lcmidnolin</em> expression was significantly upregulated in immune-related tissues upon stimulation with poly(I:C), a viral mimic, suggesting its responsiveness to viral-like signals. Confocal microscopy revealed nuclear localization of <em>Lc</em>Midnolin. Functionally, overexpression of <em>Lc</em>Midnolin suppressed poly(I:C)-induced activation of type I interferon (IFN) promoters and diminished antiviral gene expression. Consistent with this inhibitory effect, <em>Lc</em>Midnolin overexpression impaired the cellular antiviral response, as reflected by increased viral gene expression and exacerbated cytopathic effects in cells infected with spring viremia of carp virus (SVCV). Our findings provide the first evolutionary and functional insights into Midnolin in a non-mammalian vertebrate, revealing its previously unrecognized role as a regulator of the type I IFN signaling pathway.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111134"},"PeriodicalIF":3.9,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146028954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-20DOI: 10.1016/j.fsi.2026.111144
Han Wang , Chun Liu , Anicet Philippe Mane Sany , Ziquan Yang , Jie Chen , Guodong Zheng , Shuming Zou
The blunt snout bream (Megalobrama amblycephala) is an economically important freshwater fish species. However, it is highly susceptible to Aeromonas hydrophila infection, especially in intensive pond aquaculture in China. Molecular marker-assisted selection provides an efficient approach for breeding disease-resistant varieties; however, the key genes or molecular markers linked to A. hydrophila resistance remain scarce in this species. A 436 differential SNP sites with disease-resistant were screened on basis of whole-genome resequencing. Then, a high-throughput genomic KASP genotyping technique was utilized to discover favorable genes and SNP sites associated with A. hydrophila resistance. A total of 46 KASP markers were successfully developed with an accuracy of 92 %. These markers were used to genotyping 120 blunt snout bream individuals. Through trait correlation analysis and general linear models (GLM), five SNPs significantly (P < 0.05) associated with resistance to A. hydrophila were identified and mapped to five candidate genes (btnl2, cfhr2, slc47a1, neu3, nlrp1). Survival rate of individuals carrying the dominant genotype demonstrated an average survival rate of 81.39 %, which represents a 69.35 % increase in comparison with that of 48 % in total population. This effect was validated in an external population of 100 fish. These findings identify key genetic markers associated with A. hydrophila resistance and provide a direction for elucidating the underlying molecular immune mechanisms, thus establishing a genetic foundation for future breeding strategies.
{"title":"Development and identification of KASP-SNP markers correlated with Aeromonas hydrophila resistance traits in blunt snout bream (Megalobrama amblycephala)","authors":"Han Wang , Chun Liu , Anicet Philippe Mane Sany , Ziquan Yang , Jie Chen , Guodong Zheng , Shuming Zou","doi":"10.1016/j.fsi.2026.111144","DOIUrl":"10.1016/j.fsi.2026.111144","url":null,"abstract":"<div><div>The blunt snout bream (<em>Megalobrama amblycephala</em>) is an economically important freshwater fish species. However, it is highly susceptible to <em>Aeromonas hydrophila</em> infection, especially in intensive pond aquaculture in China. Molecular marker-assisted selection provides an efficient approach for breeding disease-resistant varieties; however, the key genes or molecular markers linked to <em>A. hydrophila</em> resistance remain scarce in this species. A 436 differential SNP sites with disease-resistant were screened on basis of whole-genome resequencing. Then, a high-throughput genomic KASP genotyping technique was utilized to discover favorable genes and SNP sites associated with <em>A</em>. <em>hydrophila</em> resistance. A total of 46 KASP markers were successfully developed with an accuracy of 92 %. These markers were used to genotyping 120 blunt snout bream individuals. Through trait correlation analysis and general linear models (GLM), five SNPs significantly (<em>P</em> < 0.05) associated with resistance to <em>A</em>. <em>hydrophila</em> were identified and mapped to five candidate genes (<em>btnl2, cfhr2, slc47a1, neu3, nlrp1</em>). Survival rate of individuals carrying the dominant genotype demonstrated an average survival rate of 81.39 %, which represents a 69.35 % increase in comparison with that of 48 % in total population. This effect was validated in an external population of 100 fish. These findings identify key genetic markers associated with <em>A. hydrophila</em> resistance and provide a direction for elucidating the underlying molecular immune mechanisms, thus establishing a genetic foundation for future breeding strategies.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111144"},"PeriodicalIF":3.9,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146028982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-19DOI: 10.1016/j.fsi.2026.111125
Lu Wang , Bingke Wang , Jiaxiang Zhu , Qi Zhang , Yuxuan Cui , Huajuan Shi , Chunnuan Zhang
High-fat diets (HFD) exacerbate intestinal health risks in aquaculture. This study evaluated effects of dietary sulforaphane (SFN) supplementation on intestinal morphology, biochemistry, microbiota, and metabolism in Yellow River carp (Cyprinus carpio haematopterus) fed HFD. Five isoprotein diets diets were formulated: control (CN, 6 % lipid), HFD (12.29 % lipid), and HFD with 10 (HS10), 15 (HS15), or 20 (HS20) mg/kg SFN. Results demonstrated that HFD induced marked intestinal inflammation featuring villi deformation, oxidative stress, epithelial exfoliation, mitochondrial swelling, significantly elevated pro-inflammatory cytokines (TNF-α/IL-1β/IL-6; p < 0.05), and downregulated tight junction protein genes (Occludin/ZO-1/Claudin-3; p < 0.05), concomitant with microbial dysbiosis (Proteobacteria dominance>70 %, reduced Cetobacterium) and disrupted metabolic pathways (amino acid imbalance). SFN supplementation significantly enhanced antioxidant enzyme activities (SOD/CAT/GSH-Px, p < 0.05), peaking in HS15, which also exhibited minimized pro-inflammatory cytokines and maximized tight junction expression (p < 0.05). Furthermore, 16S rRNA gene sequencing of the gut microbiota indicated that SFN restored microbial homeostasis, notably by increasing the abundance of Cetobacterium. Metabolomic analysis based on KEGG enrichment revealed that these beneficial effects were associated with the activation of FoxO signaling, enhanced lysosomal function, and upregulation of coenzyme A biosynthesis. Critically, HS15 demonstrated optimal efficacy across all parameters. Therefore, 15 mg/kg SFN is identified as the optimal dose to ameliorate intestinal health in Yellow River carp, providing a theoretical basis for functional aquafeed development.
{"title":"Sulforaphane attenuates HFD-induced enteritis in yellow river carp by restoring immune homeostasis, repairing intestinal barrier, and modulating gut microbiota","authors":"Lu Wang , Bingke Wang , Jiaxiang Zhu , Qi Zhang , Yuxuan Cui , Huajuan Shi , Chunnuan Zhang","doi":"10.1016/j.fsi.2026.111125","DOIUrl":"10.1016/j.fsi.2026.111125","url":null,"abstract":"<div><div>High-fat diets (HFD) exacerbate intestinal health risks in aquaculture. This study evaluated effects of dietary sulforaphane (SFN) supplementation on intestinal morphology, biochemistry, microbiota, and metabolism in Yellow River carp (<em>Cyprinus carpio haematopterus</em>) fed HFD. Five isoprotein diets diets were formulated: control (CN, 6 % lipid), HFD (12.29 % lipid), and HFD with 10 (HS10), 15 (HS15), or 20 (HS20) mg/kg SFN. Results demonstrated that HFD induced marked intestinal inflammation featuring villi deformation, oxidative stress, epithelial exfoliation, mitochondrial swelling, significantly elevated pro-inflammatory cytokines (<em>TNF-α/IL-1β/IL-6</em>; <em>p</em> < 0.05), and downregulated tight junction protein genes (<em>Occludin/ZO-1/Claudin-3</em>; <em>p</em> < 0.05), concomitant with microbial dysbiosis (Proteobacteria dominance>70 %, reduced <em>Cetobacterium</em>) and disrupted metabolic pathways (amino acid imbalance). SFN supplementation significantly enhanced antioxidant enzyme activities (SOD/CAT/GSH-Px, <em>p</em> < 0.05), peaking in HS15, which also exhibited minimized pro-inflammatory cytokines and maximized tight junction expression (<em>p</em> < 0.05). Furthermore, 16S rRNA gene sequencing of the gut microbiota indicated that SFN restored microbial homeostasis, notably by increasing the abundance of <em>Cetobacterium</em>. Metabolomic analysis based on KEGG enrichment revealed that these beneficial effects were associated with the activation of FoxO signaling, enhanced lysosomal function, and upregulation of coenzyme A biosynthesis. Critically, HS15 demonstrated optimal efficacy across all parameters. Therefore, 15 mg/kg SFN is identified as the optimal dose to ameliorate intestinal health in Yellow River carp, providing a theoretical basis for functional aquafeed development.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"170 ","pages":"Article 111125"},"PeriodicalIF":3.9,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146017896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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