Fish & shellfish immunology最新文献

{"title":"Enhanced Six-Month Protection and Immune Responses in Four-Finger Threadfin Following Vaccination with Formalin-Killed Streptococcus iniae.","authors":"Andre Giovanni, Yin-Ze Shi, Atiek Rahmawaty, Pei-Chi Wang, Shih-Chu Chen","doi":"10.1016/j.fsi.2026.111795","DOIUrl":"https://doi.org/10.1016/j.fsi.2026.111795","url":null,"abstract":"<p><p>Streptococcus iniae is a major bacterial pathogen causing severe economic losses in marine and freshwater aquaculture worldwide. This study evaluated the long-term protective efficacy and immunostimulatory effects of a formalin-killed cell (FKC) vaccine, with and without Montanide ISA 763 adjuvant, against S. iniae infection in four-finger threadfin (Eleutheronema tetradactylum). Fish were assigned to three groups: control, FKC, and FKC combined with Montanide ISA 763 (FKC+ISA). Vaccinated fish received 1.5 × 10⁹ CFU/fish and were challenged at 1, 3, and 6 months post-vaccination (mpv) using the virulent S. iniae GSI-111 strain. An additional heterologous challenge using the S. iniae T6 strain was performed at 6 mpv. Immune-related gene expression, including complement component 2 (C2), cluster of differentiation 8, tumor necrosis factor-α, interleukin-10, and interleukin-12 in spleen and kidney tissues, as well as serum lysozyme activity and S. iniae-specific immunoglobulin M (IgM) antibody responses, were evaluated throughout the experimental period. Both vaccinated groups exhibited significantly stronger immune responses than the control group, with the FKC+ISA group demonstrating the greatest and most sustained immunological activation. Elevated serum lysozyme activity and specific IgM antibody levels were maintained for up to 6 mpv. Following homologous challenge with the GSI-111 strain, the FKC+ISA group achieved 100% relative percent survival (RPS) under the present experimental conditions at all challenge time points, whereas the FKC group provided consistently high but slightly lower protection (92.9-97.2% RPS). During the heterologous challenge with the T6 strain at 6 mpv, the FKC+ISA group again achieved 100% RPS under the present experimental conditions, while the FKC group achieved 78.6% RPS. In contrast, the control group experienced high mortality, with survival rates ranging from 50-75%. Re-isolation analysis confirmed the absence or marked reduction of S. iniae in surviving vaccinated fish. These findings demonstrate that the Montanide ISA 763-adjuvanted FKC vaccine elicits robust and durable humoral and cellular immune responses, providing long-term homologous and heterologous protection against S. iniae infection in four-finger threadfin.</p>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":" ","pages":"111795"},"PeriodicalIF":4.2,"publicationDate":"2026-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149215309","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}

{"title":"Ddx1 is essential for zebrafish development to adulthood but has no detectable effect on the response to tilapia lake virus (TiLV) in larvae.","authors":"Niedharsan Pooranachandran, Miriam Mojzesz, Justyna Starzyk, Maria Zawisza, Adam Chromiec, Magdalena Widziolek, Tomasz K Prajsnar, Win Surachetpong, Magdalena Chadzinska, Mikolaj Adamek, Krzysztof Rakus","doi":"10.1016/j.fsi.2026.111785","DOIUrl":"10.1016/j.fsi.2026.111785","url":null,"abstract":"<p><p>DExD/H-box RNA helicases are multifunctional regulators of RNA metabolism and some are associated with host defence against viruses. However, the in vivo roles of individual family members remain insufficiently characterised. Ddx1 is one such example, implicated in antiviral signalling as well as in the replication of several viruses. In this study, we investigated the function of Ddx1 during vertebrate development and viral infection in zebrafish (Danio rerio) model using both loss-of-function and gain-of-function approaches. CRISPR/Cas9-mediated knockout of ddx1 resulted in viable embryos and larvae without overt developmental abnormalities; however, knockouts failed to survive to adulthood, indicating that Ddx1 is required for later stages of development. To assess its role in antiviral defence, ddx1 knockout and wild-type larvae were experimentally infected with tilapia lake virus (TiLV), a virus known to induce a strong type I interferon response in zebrafish. Survival rates, viral loads, and expression of selected type I interferon pathway genes (rig-I, ifnφ1, mxa) were comparable between genotypes, demonstrating that Ddx1 is not essential for the larval antiviral response to TiLV. Consistently, overexpression of ddx1 did not enhance resistance to infection. Together, these findings indicate that while Ddx1 is critical for zebrafish survival to adulthood, it does not play a measurable role in early antiviral immunity against TiLV in zebrafish larvae.</p>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":" ","pages":"111785"},"PeriodicalIF":4.2,"publicationDate":"2026-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149206763","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}

{"title":"Visualizing the 3D morphological structure and dynamic defensive characteristics of teleost mucus barrier through an ex vivo approach in flounder (Paralichthys olivaceus).","authors":"Jincheng Wang, Ziyi Zhang, Yanrui Xu, Xiuzhen Sheng, Ningge Zhang, Xiaoqian Tang, Jing Xing, Heng Chi, Wenbin Zhan","doi":"10.1016/j.fsi.2026.111784","DOIUrl":"10.1016/j.fsi.2026.111784","url":null,"abstract":"<p><p>The fish mucus barrier serves as the first line of defense against pathogen invasion, and its structural and functional changes are key indicators for assessing fish health. However, due to limitations in situ observation techniques, the three-dimensional (3D) architecture and dynamic barrier functions of the fish mucus layer have long remained poorly understood. In this study, using teleost flounder (Paralichthys olivaceus) as a model, we established an integrated approach combining ex vivo tissue culture with lectin fluorescence labeling and confocal laser scanning microscopy, which maintained high cell viability within 6 h, achieving high-fidelity 3D reconstruction of the mucus layer on the gills, hindgut, and skin, and revealed tissue-specific differences in mucus layer thickness, surface area, ultrastructure, and 3D morphology. Using fluorescent microbeads (FMBs) of varying diameters, we demonstrated that the mucus layer functions as a size-dependent sieving barrier. By simulating immersion exposure to inactivated and live Edwardsiella tarda, and 1 μm FMBs, we further elucidated the differential handling of distinct particles by the mucus layer during 1 h: inactivated bacteria were partially retained within the mucus network, partially penetrated to the epithelial surface, and partially cleared via shedding of mucus clumps; live bacteria, although partially captured, progressively traversed to the epithelial surface while triggering mucus layer elevation and shedding of bacteria-containing mucus clumps; while 1 μm microbeads rapidly penetrated but subsequently became anchored within the mesh, showing minimal further displacement and rarely undergoing clearance. These results demonstrated that the mucus layer acted as a dynamic barrier system, exerting its defensive function through the synergistic action of physical entrapment and active clearance and at the same time promoting the adhesion of the biotic/abiotic particles. This study provides new insights into the structural and dynamic defensive functions of the teleost mucus barrier.</p>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":" ","pages":"111784"},"PeriodicalIF":4.2,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149192241","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}

{"title":"Immune responses and seasonal red sea bream iridovirus dynamics following formalin-inactivated vaccination in farmed rock bream (Oplegnathus fasciatus).","authors":"Sung-Bin Moon, Min Jae Kim, Woo Ju Kwon, Min-Young Sohn, Chan-Il Park, Kyung-Ho Kim","doi":"10.1016/j.fsi.2026.111781","DOIUrl":"https://doi.org/10.1016/j.fsi.2026.111781","url":null,"abstract":"<p><p>Red sea bream iridovirus (RSIV) remains a major constraint on rock bream aquaculture, but vaccine-associated immune responses during natural field exposure are poorly understood. We monitored formalin-inactivated RSIV-vaccinated and unvaccinated rock bream from post-vaccination land-based rearing through a seasonal RSIV episode in commercial marine net pens. Splenic RSIV load and the mRNA expression of MyD88, IL-1β, IRF3, Mx, PKR, membrane-bound IgT (mIgT), and secretory IgT (sIgT) were assessed longitudinally. Full-length major capsid protein sequences obtained from RSIV-positive fish in both cohorts were identical and clustered within the broad RSIV-type lineage represented by the vaccine antigen. Vaccinated fish maintained lower splenic viral loads than unvaccinated fish throughout field sampling and showed a coordinated immune-gene mRNA response during natural exposure. MyD88, IRF3, Mx, and PKR remained elevated at the final sampling, although the broadest response, involving all seven genes, occurred earlier during the main field-response period. Duration-normalized area-under-the-curve analysis identified positive field-phase responses across the complete gene panel; principal component analysis and two-way hierarchical clustering identified coordinated vaccination- and phase-associated multigene profiles. These findings link formalin-inactivated vaccination with lower late-stage RSIV load and a temporally organized immune response under commercial net-pen conditions.</p>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":" ","pages":"111781"},"PeriodicalIF":4.2,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149180299","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}

{"title":"Combined amino acid mutations in the glycoprotein of infectious hematopoietic necrosis virus attenuate virulence and confer strong immunogenicity in rainbow trout.","authors":"Rui Ao, Mingzhe Li, Zhongyu Zhang, Guangqing Wu, Shuaibo Li, Yulu Ma, Xueting Guan, Gefeng Xu, Xinjia Lv, Min Liu","doi":"10.1016/j.fsi.2026.111782","DOIUrl":"https://doi.org/10.1016/j.fsi.2026.111782","url":null,"abstract":"<p><p>Infectious hematopoietic necrosis virus (IHNV) is a major threat to the salmonid aquaculture industry, causing mortality rates exceeding 90% in juvenile salmonids. Our previous study showed that single-site mutations at amino acid residues 67, 107, 221 or 256 of the IHNV G protein reduced IHNV virulence, and immunization of rainbow trout with attenuated mutants improved survival after challenge with wild-type (wt) IHNV-HLJ09. To investigate the effects of combining these G-protein substitutions on IHNV virulence and protective efficacy, we employed a reverse genetics system to construct four recombinant viruses (rIHNVs) carrying combined mutations in the G protein, designated rIHNV-_G67-107, rIHNV-G_67-256, rIHNV-G_67-107-221, and rIHNV-G_67-107-256. Pathogenicity assays showed that survival rates in fish inoculated with triple mutants rIHNV-G_67-107-221 and rIHNV-G_67-107-256 reached 86.67%, exceeding those of double mutants and the wtIHNV-HLJ09 group (13.33%). In vivo viral copy numbers were significantly lower in fish infected with the rIHNVs, with rIHNV-G_67-107-221 showing the lowest viral load. Notably, vaccination with rIHNV-G_67-107-221 provided significant protection against challenge with wtIHNV-HLJ09, achieving an 88.75% relative percent survival (RPS). Moreover, compared with wtIHNV-HLJ09, rIHNV-G_67-107-221 induced higher expression levels of TLR3, IFN-I, and IL-1β, together with reduced IL-10 expression, and elicited earlier and higher levels of IHNV-specific IgM. In conclusion, these results suggest that combined mutations at sites 67, 107, and 221 of IHNV G protein effectively attenuate virulence and enhance immunogenicity. These findings indicate that rIHNV-G_67-107-221 offer a favorable balance between attenuation and immunogenicity, supporting its further evaluation as a promising live-attenuated vaccine candidate against IHNV.</p>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":" ","pages":"111782"},"PeriodicalIF":4.2,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149180269","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}

{"title":"Genome-wide characterization of Pm-Rel DNA-binding landscape in pearl oyster Pinctada fucata martensii.","authors":"Li Zhang, Yujia Cao, Chaojun Liu, Xiaowen Huang, Zhihao Chen, Xiaowen Lu, Yu Jiao, Qingheng Wang, Chuangye Yang, Yuewen Deng","doi":"10.1016/j.fsi.2026.111774","DOIUrl":"10.1016/j.fsi.2026.111774","url":null,"abstract":"<p><p>Pm-Rel, a key member of the NF-κB family, has been implicated in transplantation-induced immune responses in Pinctada fucata martensii; however, its genome-wide DNA-binding profile and associated regulatory features remain poorly characterized. Here, we generated a Pm-Rel-specific antibody and performed chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) in pearl oyster hemocytes and identified 4894 Pm-Rel-associated binding peaks and annotated 3711 nearby genes. Functional enrichment analyses showed that these genes were significantly enriched in apoptosis and immune-associated pathways, including the tumor necrosis factor (TNF), apoptosis, and JAK-STAT signaling pathway. Motif analysis identified a highly enriched κB-like motif together with additional enriched sequence elements within Pm-Rel-associated regions. Representative sequences, including GGGGAATTCC, CTAAAAATAG, and AGTCGGAATT, were subsequently evaluated using dual-luciferase reporter assays. Combined expression of Pm-Rel and Pm-NF-κB activated reporter constructs containing the selected sequences, with the AGTCGGAATT-containing reporter showing the highest activity under the tested conditions. Collectively, this study provides a genome-wide characterization of Pm-Rel DNA-binding features in P. f. martensii, offering genomic insights into NF-κB-mediated immune and cellular regulatory processes in mollusks.</p>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":" ","pages":"111774"},"PeriodicalIF":4.2,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149166263","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}

{"title":"Functional characterization of grass carp OXR1 in response to GCRV infection.","authors":"Yanxia Jiang, Li Wu, Zhen Gan, Jing Liu, Liang Hu, Yang He, Yingqi Gao, Junhua Li, Xinyu Liang","doi":"10.1016/j.fsi.2026.111773","DOIUrl":"10.1016/j.fsi.2026.111773","url":null,"abstract":"<p><p>Oxidation resistance protein 1 (OXR1) protects cells from oxidative injury in several vertebrate systems, but its role during viral infection in teleosts is unknown. We cloned and characterized grass carp OXR1 (Ctenopharyngodon idella; CiOXR1) and examined its response to grass carp reovirus (GCRV). The 959-bp CiOXR1 cDNA contains a 774-bp open reading frame encoding a 257-amino-acid TLDc-domain protein. CiOXR1 transcripts were detected in all tissues examined in healthy grass carp, with the highest basal abundance in brain, followed by heart. Following genotype II GCRV-HZ08 challenge in grass carp, CiOXR1 transcript abundance increased in brain and heart. In vitro, treatment with LPS, poly(I:C), or H₂O₂ increased CiOXR1 transcript abundance in grass carp ovary (GCO) cells. GFP-CiOXR1 localized mainly to the cytoplasm of GCRV-infected GCO cells. Cell-based localization and functional assays used genotype I GCRV-873, which increased DCFH-probe fluorescence. Infected cells transfected with 3HA-CiOXR1 showed lower DCFH fluorescence, lower SOD1 and SOD2 transcript abundance, and reduced accumulation of viral RNA and viral proteins. TCID₅₀ assays further supported inhibition of infectious-virus production by CiOXR1. Total caspase-3 and caspase-9 protein abundance, their transcript levels, and selected innate immune-response markers were also reduced, whereas no significant difference in STING transcript abundance was detected. Cas13d-mediated knockdown of CiOXR1 yielded reciprocal transcript-level changes. Together, the complementary expression and knockdown results show that CiOXR1 expression is inversely related to GCRV molecular-marker accumulation and accompanies coordinated changes in intracellular oxidation, total caspase abundance, and selected innate immune-response markers. These findings further support an antiviral role for CiOXR1 and provide a foundation for research on the prevention and control of grass carp haemorrhagic disease.</p>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":" ","pages":"111773"},"PeriodicalIF":4.2,"publicationDate":"2026-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149166627","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}

{"title":"PtCdc42 is involved in hemocyte mediated immune responses of Portunus trituberculatus under Vibrio parahaemolyticus stimulation","authors":"Xiaona Zhang,&nbsp;Fei Wu,&nbsp;Hui Chen,&nbsp;Mengting Zhen,&nbsp;Chang Sun,&nbsp;Yaomin Wang,&nbsp;Ce Shi,&nbsp;Ronghua Li,&nbsp;Yangfang Ye,&nbsp;Weiwei Song,&nbsp;Chunlin Wang,&nbsp;Changkao Mu","doi":"10.1016/j.fsi.2026.111757","DOIUrl":"10.1016/j.fsi.2026.111757","url":null,"abstract":"&lt;div&gt;&lt;ul&gt;&lt;li&gt;&lt;span&gt;•&lt;/span&gt;&lt;span&gt;&lt;div&gt;Treatment with &lt;em&gt;Vibrio parahaemolyticus&lt;/em&gt; triggers significant up regulation of Cdc42 expression in hemocytes of &lt;em&gt;Portunus trituberculatus.&lt;/em&gt;&lt;/div&gt;&lt;/span&gt;&lt;/li&gt;&lt;li&gt;&lt;span&gt;•&lt;/span&gt;&lt;span&gt;&lt;div&gt;&lt;em&gt;Pt&lt;/em&gt;Cdc42 may positively regulates hemocyte migration under &lt;em&gt;V. parahaemolyticus&lt;/em&gt; and LPS stimulation.&lt;/div&gt;&lt;/span&gt;&lt;/li&gt;&lt;li&gt;&lt;span&gt;•&lt;/span&gt;&lt;span&gt;&lt;div&gt;&lt;em&gt;Pt&lt;/em&gt;Cdc42 may contribute to the hemocyte phagocytic capacity of crabs against &lt;em&gt;V. parahaemolyticus.&lt;/em&gt;&lt;/div&gt;&lt;/span&gt;&lt;/li&gt;&lt;li&gt;&lt;span&gt;•&lt;/span&gt;&lt;span&gt;&lt;div&gt;&lt;em&gt;Pt&lt;/em&gt;Cdc42 modulates the transcriptional levels of multiple antimicrobial peptides.&lt;/div&gt;&lt;/span&gt;&lt;/li&gt;&lt;/ul&gt;&lt;/div&gt;&lt;div&gt;&lt;div&gt;Rho family small GTPases operate as core molecular switches to modulate vertebrate immune responses, among which cell division cycle 42 (Cdc42) acts as an important member. Although several studies have explored its roles in cellular immunity and pathogen defense in invertebrates, the specific functions and regulatory mechanisms of Cdc42 underlying hemocyte mediated immune responses of &lt;em&gt;Portunus trituberculatus&lt;/em&gt; remain to be further elucidated. In the current work, the Cdc42 gene designated &lt;em&gt;Pt&lt;/em&gt;Cdc42 was cloned from &lt;em&gt;P. trituberculatus&lt;/em&gt;. Tissue expression profiling demonstrated ubiquitous transcription of &lt;em&gt;Pt&lt;/em&gt;Cdc42 in major immune related tissues, including intestines, hepatopancreas, hemocytes and gill. Treatment with &lt;em&gt;Vibrio parahaemolyticus&lt;/em&gt; markedly upregulated &lt;em&gt;Pt&lt;/em&gt;Cdc42 expression. RNAi mediated knockdown of &lt;em&gt;Pt&lt;/em&gt;Cdc42 significantly suppressed the mRNA levels of multiple antimicrobial peptide genes induced by &lt;em&gt;V. parahaemolyticus&lt;/em&gt;. Meanwhile, the results indicate that &lt;em&gt;Pt&lt;/em&gt;Cdc42 may participate in hemocyte migration triggered by &lt;em&gt;V. parahaemolyticus&lt;/em&gt; and LPS, as well as &lt;em&gt;V. parahaemolyticus&lt;/em&gt; stimulated hemocyte phagocytosis.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;Rho family small GTPases operate as core molecular switches to modulate vertebrate immune responses, among which cell division cycle 42 (Cdc42) acts as an important member. Although several studies have explored its roles in cellular immunity and pathogen defense in invertebrates, the specific functions and regulatory mechanisms of Cdc42 underlying hemocyte mediated immune responses of &lt;em&gt;Portunus trituberculatus&lt;/em&gt; remain to be further elucidated. In the current work, the Cdc42 gene designated &lt;em&gt;Pt&lt;/em&gt;Cdc42 was cloned from &lt;em&gt;P. trituberculatus&lt;/em&gt;. Tissue expression profiling demonstrated ubiquitous transcription of &lt;em&gt;Pt&lt;/em&gt;Cdc42 in major immune related tissues, including intestines, hepatopancreas, hemocytes and gill. Treatment with &lt;em&gt;Vibrio parahaemolyticus&lt;/em&gt; markedly upregulated &lt;em&gt;Pt&lt;/em&gt;Cdc42 expression. RNAi mediated knockdown of &lt;em&gt;Pt&lt;/em&gt;Cdc42 significantly suppressed the mRNA levels of multiple antimicrobial peptide genes induced by &lt;em&gt;V. parahaemolyticus&lt;/em&gt;. Meanwhile, the results indicate that &lt;em&gt;Pt&lt;/em&gt;Cdc42 may partici","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"180 ","pages":"Article 111757"},"PeriodicalIF":4.2,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149135562","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}

{"title":"Salt-inducible kinase 2b (Sik2b) promotes liver inflammation by phosphorylating BHLHE41 in zebrafish (Danio rerio).","authors":"Lin Ou, Shangzhe Han, Tingting Hao, Geye Ding, Kangsen Mai, Qinghui Ai","doi":"10.1016/j.fsi.2026.111763","DOIUrl":"https://doi.org/10.1016/j.fsi.2026.111763","url":null,"abstract":"<p><p>Long-term feeding of palm oil-based diets readily induces inflammatory response in farmed fish, compromising aquaculture efficiency and food safety. Salt-inducible kinase 2 (SIK2), an energy-sensing kinase that orchestrates immunometabolic crosstalk in mammals, may participate in this process. However, little attention has been given to the function of its ortholog in fish. Here, using sik2b knockout zebrafish models together with sik2b knockdown and overexpression experiments in ZFL cells, we found that loss of sik2b induced an anti-inflammatory phenotype in zebrafish hepatocytes, whereas its overexpression elicited inflammatory response. In the feeding trial, sik2b knockout alleviated hepatic injury in zebrafish induced by the complete replacement of fish oil with palm oil. Similarly, in cultured ZFL cells, sik2b knockdown effectively inhibited the expression of inflammatory mediators induced by palmitic acid (PA). Mechanistically, Sik2b interacted with BHLHE41 and phosphorylated it, leading to the cytoplasmic accumulation of BHLHE41, which relieved its transcriptional repression of tnfa, ultimately enhancing tnfa promoter activity. In conclusion, this study uncovered a previously unidentified regulatory role of Sik2b-BHLHE41 signaling axis in hepatic inflammatory response in fish, providing a scientific rationale for the future design of anti-inflammatory targets in aquaculture.</p>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":" ","pages":"111763"},"PeriodicalIF":4.2,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149126959","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}

{"title":"Histopathological and functional evidence of intestinal mucosal disruption in emaciated olive flounder (Paralichthys olivaceus) infected with Enteromyxum leei","authors":"Hyobin Lee,&nbsp;Han-Kyu Lim,&nbsp;Jeong-Hyeon Cho","doi":"10.1016/j.fsi.2026.111657","DOIUrl":"10.1016/j.fsi.2026.111657","url":null,"abstract":"<div><div>Emaciation disease associated with <em>Enteromyxum leei</em> infection is a major health concern in olive flounder (<em>Paralichthys olivaceus</em>) aquaculture, but the structure–function basis underlying this condition remains incompletely understood. In this study, we investigated whether emaciation in <em>E. leei</em>-infected olive flounder is linked to intestinal mucosal disruption and impaired digestive and absorptive function. Fish were classified based on external appearance, relative condition factor, and polymerase chain reaction-based detection of <em>E. leei</em>. Infected fish exhibited markedly lower relative condition factor, hepatosomatic index, and viscerosomatic index, accompanied by increased gastrointestinal tract length. Histopathological profiling revealed region-specific parasite distribution from the pyloric caeca to the distal intestine, accompanied by mucosal fold shortening, epithelial disruption, goblet/mucous cell depletion, altered Alcian blue–periodic acid–Schiff staining characteristics, and reduced cholecystokinin-positive enteroendocrine cell density. In the anterior intestine, alkaline phosphatase, amylase, and trypsin levels were significantly lower in infected fish, whereas chymotrypsin and lipoprotein lipase did not differ between groups. At the transcriptional level, <em>FABP2</em> and <em>ApoA-IV</em> were downregulated in infected fish, whereas <em>HSL</em>, <em>LPL</em>, <em>SREBF1</em>, and <em>TRP2</em> were upregulated. Correlation analysis showed positive association between <em>FABP2</em> expression and both amylase and trypsin levels, whereas the marked upregulation of <em>TRP2</em> was not associated with a corresponding increase in trypsin levels. These findings indicate that <em>E. leei</em>-associated emaciation is characterized by intestinal mucosal failure, disruption of the digestion–absorption axis, and incomplete transcriptional compensation, supporting its interpretation as a maldigestion–malabsorption syndrome.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"178 ","pages":"Article 111657"},"PeriodicalIF":4.2,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148773075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}