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Fish & Shellfish Immunology
Academic Press
Fish & Shellfish Immunology

Academic Press

1050-4648

Fish & Shellfish Immunology/Journal Fish & Shellfish ImmunologySCIISTP
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    Bioactivity of orange-spotted grouper (Epinephelus coioides) cathepsin L: Proteolysis of bacteria and regulation of the innate immune response

    Chiang Y.-R.Wang L.-C.Lin J.H.-Y.Lin H.-T....
    10页
    查看更多>>摘要:? 2022 Elsevier LtdCathepsin L (CTSL) is a cysteine endopeptidase involved in protein degradation mainly in lysosomes. Following activation in an acidic environment, it plays a key role in a variety of physiological, immunological, and pathological processes. The biological function of CTSL in teleost remains unclear. Immunohistochemical analysis revealed that CTSL was expressed mainly in lymphoid organs, head kidney, trunk kidney, and liver, which particularly was expressed in leukocyte-like cells. We performed two forms of recombinant CTSL (rCTSL and rTCTSL) derived from orange-spotted grouper (Epinephelus coioides) to elucidate the role of CTSL in teleost innate immunity, based on differences in immune-related gene expression. We determined that rCTSL has a proteolytic function whereas rTCTSL does not. Under CTSL activation, we observed increases in IL-1β, IL-6, IL-12, IFNγ, CCL-1, CCL-3, epinecidin-1, lysozyme, and IgM. The bacteriolytic activity of rCTSL was more pronounced against Gram-positive bacteria than Gram-negative bacteria. Our findings indicate CTSL plays multiple roles in the reactions of innate immunity.

    Flow cytometric characterization of the hemocytes of sea hares from tidal pools in Jeju Island off the south coast of Korea

    Kajino N.Choi K.-S.Hong H.-K.
    10页
    查看更多>>摘要:? 2022 Elsevier LtdThe members in the family Aplysidae known as sea hares play a crucial role as a grazer in small tidal pools or shallow subtidal hard bottoms. Like other marine gastropods, hemocyte types and functions of sea hares are limitedly known. This study identified and characterized the hemocytes of common Aplysia species Aplysia kurodai, A. juliana, and A. oculifera in rocky tidal pools in Jeju Island off the south coast of Korea using flow cytometry and light microscopy. The flow cytometry identified three different hemocytes in the hemolymph of the three sea hare species: granulocytes, hyalinocytes, and blast-like cells. The granulocytes exhibited pseudopodia on the cell surface and granules in the cytoplasm. Morphology of the hyalinocyte was similar to that of the granulocytes, while they lack cytoplasmic granules. The blast-like cells were small and round, with very thin cytoplasm. The hyalinocytes were the most abundant in the hemolymph, accounting for 89.8–92.6% of the total hemocytes. Flow cytometry indicated that the granulocytes and blast-like cells were less than 5.6% and 5.4% of the total hemocyte populations. Flow cytometry also revealed that the granulocytes and hyalinocytes are engaged in cellular defensive activities such as intra-cellular lysosomal content, phagocytosis, and ROS production. The mean lysosomal contents of the granulocytes (0.4 × 105–0.2 × 105 A U.) were 2–3 times higher than that of hyalinocytes (0.2 × 105–0.6 × 105 A U.). In addition, the ROS production of the granulocytes (0.98 × 106–1.95 × 106 A U.) was about twice higher than that of the hyalinocytes (0.62 × 106–1.14 × 106 A U.). Of the three species of sea hares, the granulocytes showed comparatively higher phagocytosis capacity (70.4–92.3%) than that of the hyalinocytes (34.8–46.0%). Flow cytometry and microscopy indicated that the hemocyte types and their functions were identical, regardless of the species.

    Polystyrene nanoplastics decrease molting and induce oxidative stress in adult Macrobrachium nipponense

    Yang P.Su M.Zhang G.Fan W....
    7页
    查看更多>>摘要:? 2022 Elsevier LtdThe widespread occurrence and accumulation of plastic waste have been globally recognized as a critical issue. However, few researches have evaluated the adverse effects of nanoplastics to freshwater organisms. Thus, here, the effects of polystyrene nanoplastics (PS-NP) on the physiological changes (i.e., molting) and enzyme activity of oxidative stress were investigated in the adult freshwater prawn Macrobrachium nipponense. Based on a previous study and environmental microplastic concentrations, the prawn was exposed to 0, 0.04, 0.4, 4, and 40 mg/L waterborne PS-NP for 21 days. The results showed that growth and survival-related parameters were not affected by all PS-NP groups, while the molting rate were significantly decreased in the 4 and 40 mg/L PS-NP group. Meanwhile, the expression of molting-related gene (calcium–calmodulin-dependent protein kinase I, ecdysteroid receptor, and leucine-rich repeat-containing G-protein-coupled receptor 2) were significantly decreased. H2O2 content was significantly increased in all PS-NP groups relative to the control. Lower concentrations of PS-NP increased the activity of superoxide dismutase (SOD), glutathione S-transferase (GST), and glutathione peroxidase (GSH-Px), whereas increased concentrations, decreased SOD, GST, and GSH-Px activity. These results suggest that chronic exposure to PS-NP at an environmental concentration impaired molting and induced oxidative stress in the adult river prawn Macrobrachium nipponense. The findings provided basic information for assessing the risk assessment of nanoplastics and revealing the molecular mechanisms of nanoplastics toxicity.

    Expression of Interleukin-2 receptor subunit gamma (IL-2Rγ) and its binding with IL-2 induced activation of CD4 T lymphocytes in flounder (Paralichthys olivaceus)

    Zhao M.Xing J.Tang X.Sheng X....
    11页
    查看更多>>摘要:? 2022 Elsevier LtdInterleukin-2 receptor (IL-2R), as the specific ligand of interleukin-2 (IL-2), binds to IL-2 and transmits signals and then can induce the proliferation of T lymphocytes in mammals. In this paper, the subunit of IL-2R in flounder (Paralichthys olivaceus), interleukin-2 receptor subunit gamma (IL-2Rγ) was cloned, and polyclonal antibodies (Abs) against its extracellular region were produced, then the expression of flounder IL-2Rγ (fIL-2Rγ) at transcriptional and cellular levels were characterized. Moreover, the interaction of flounder IL-2 (fIL-2) with fIL-2Rγ was investigated, and the variations on CD4+/IL-2Rγ+ cells in flounder after treatment with recombinant IL-2 (rIL-2), anti-IL-2Rγ Abs were detected, respectively. The results showed that fIL-2Rγ protein had a typical fibronectin type III (FN3) domain. The Abs could specifically recognize native fIL-2Rγ molecules at 39.9 kDa. FIL-2Rγ was localized on both T and B lymphocytes, and the percentages of CD4+/IL-2Rγ+ and IgM+/IL-2Rγ+ lymphocytes were high in spleen. In addition, pBiFC-VN173-IL-2Rγ plasmids could bind to pBiFC-VC155-IL-2 plasmids. The percentage of CD4+/IL-2Rγ+ lymphocytes was significantly decreased after blocking with anti-IL-2Rγ Abs both in vivo and in vitro. In the meantime, four T cell markers genes and six IL-2-IL-2R pathway genes were down-regulated in anti-IL-2Rγ Abs group. These results first demonstrated that fIL-2Rγ molecules were expressed on both T and B lymphocytes in flounder, and the bond between fIL-2Rγ and fIL-2 activated the CD4 T lymphocytes. This study gave a new sight into the exploration of IL-2R function on T lymphocytes proliferation in fish.

    Size-dependent resistance to amoebic gill disease in na?ve Atlantic salmon (Salmo salar)

    Smith A.J.Adams M.B.Crosbie P.B.B.Nowak B.F....
    9页
    查看更多>>摘要:? 2022 Elsevier LtdAmoebic gill disease, caused by the protozoan ectoparasite Neoparamoeba perurans, remains a significant threat to commercial Atlantic salmon aquaculture operations worldwide, despite partial control afforded by selective breeding and therapeutic intervention. Anecdotal reports from commercial producers suggest that historically, smaller Atlantic salmon smolts are more susceptible to AGD than larger smolts. Here, large (>350 g) and small (<200 g) commercially sourced, AGD-na?ve Atlantic salmon cohorts were experimentally exposed to 50 N. perurans trophozoites L?1 without intervention. Progression and severity of AGD in challenged cohorts was evaluated through gill pathology, using gill score and histological examination, and quantification of gill-associated amoebae burden using qPCR. To determine the potential basis for differences in AGD susceptibility between cohorts, transcriptome analysis was conducted using RNA extracted from whole gill arches. Overall, the large Atlantic salmon cohort had significantly lower gill parasite burdens and reduced AGD-related gross pathology compared to the small cohort. Relative gill load of N. perurans appeared to be proportional to gill score in both size classes, with larger smolts typically observed to have comparatively reduced parasite burdens at a given gill score. Moreover, comparison between gene expression profiles of large and small smolts highlighted upregulation of genes consistent with elevated immune activity in large smolts. Combined, the results presented here provide strong evidence of size-dependent resistance to AGD in AGD-na?ve Atlantic salmon.

    Characterization of scavenger receptor MARCO in orange-spotted grouper, Epinephelus coioides

    Xu S.Wang S.Yang M.Han C....
    9页
    查看更多>>摘要:? 2022Macrophage receptor with collagenous structure (MARCO) is a scavenger receptor that plays a crucial role in the immune response against microbial infections. To clarify the roles of fish MARCO in Singapore grouper iridovirus (SGIV) infection, we identified and characterized Ec-MARCO in the orange-spotted grouper (Epinephelus coioides). The Ec-MARCO encoded a 370-amino acid protein with transmembrane region, coiled coil region and SR domain, which shared high identities with reported MARCO. The abundant transcriptional level of Ec-MARCO was found in spleen, head kidney and blood. And the Ec-MARCO expression was significantly up-regulated in grouper spleen (GS) cells after infection with SGIV in vitro. Subcellular localization analysis revealed that Ec-MARCO was mainly distributed in the cytoplasm and on the cell membrane. Ec-MARCO knockdown in vitro significantly inhibited SGIV infection in GS cells, as evidenced by reduced decreased SGIV major capsid protein (MCP) transcription and MCP protein expression. Further studies showed that Ec-MARCO knockdown positively regulated proinflammatory cytokines and interferon-stimulated genes, and enhanced IFN and ISRE promoter activities. However, overexpression of Ec-MARCO did not affect SGIV entry into host cells. In summary, our results suggested that Ec-MARCO affected SGIV infection by regulating antiviral innate immune response.

    Cold stress after swimming fatigue decreases immunity-related gene expression in the spleen of the Chinese sucker

    Qin C.Xie J.Shi X.Tan J....
    10页
    查看更多>>摘要:? 2022For migratory fish, passing through the cold, fast flowing water of a dam causes stress, leading to disease and even death. To determine the immune response to cold stress in a dam-lake after swimming fatigue in Chinese sucker (Myxocyprinus asiaticus), the spleen mRNA expression profiles in response to cold stress (CS) after fatigue stress (FS) were compared with that of the control (SS). We identified 40,952 differentially expressed genes (DEGs) in the spleen for at least one comparison among 211,397 unigenes. We identified 11,869 DEGs (4,968 upregulated and 6,901 downregulated), 17,803 DEGs (10,610 upregulated and 7,193 downregulated), and 30,579 DEGs (20,652 upregulated and 9,927 downregulated) in the SS vs. FS, SS vs. CS, and FS vs. CS comparisons, respectively. Enrichment analysis indicated the involvement of the immune system and infectious diseases, including the toll-like receptor pathway, the complement and coagulation cascade, and the natural killer cell-mediated cytotoxicity pathway. There were 2,991 DEGs (271 upregulated and 2,720 downregulated), and 2,878 DEGs (873 upregulated and 2,005 downregulated) associated with these pathways in the SS vs. FS and SS vs. CS comparisons, respectively. In the cold stress after fatigue group, the expression levels of heat shock protein (HSP) 70 and HSP90 genes were significantly upregulated; however, more immune response genes showed significantly downregulated expression in SS vs. CS compared with that in SS vs. FS, including those encoding tumor necrosis factor, C–C motif chemokines (3, 8, and 13), complement components (C3, C4, C6, and C7), immunoglobulin, and cathepsins. Overall, cold stress combined with swimming fatigue from passing the dam resulted in the downregulation of many immune genes, suggesting that the Chinese sucker might have experienced serious immune suppression.

    Functional characterization of BAG3 in orange-spotted grouper (Epinephelus coioides) during viral infection

    Liang Z.Zhang S.Zou Z.Li J....
    11页
    查看更多>>摘要:? 2022 Elsevier LtdBcl-2-associated athanogene 3 (BAG3) is a cochaperone protein that interacts with Bcl-2 and mediate cell death. However, little is known about the roles of fish BAG3 during viral infection. In this study, we characterized a BAG3 homolog from orange-spotted grouper (Epinephelus coioides) (EcBAG3) and investigated its roles during viral infection. The EcBAG3 protein encoded 579 amino acids with typical WW, PXXP and BAG domains, which shared high identities with reported fish BAG3. Quantitative real-time PCR (qRT-PCR) analysis revealed that EcBAG3 was highly expressed in brain and heart. And the expression of EcBAG3 was significantly up-regulated after red-spotted grouper nervous necrosis virus (RGNNV) stimulation in vitro. EcBAG3 overexpression could promoted the expression of viral genes (coat protein (CP) and RNA-dependent RNA polymerase (RdRp)), which was enhanced by co-transfection with Hsp70 and Hsp22. Also, EcBAG3 overexpression up-regulated the expression of LC3-Ⅱ and down-regulated the expression of Bax and BNIP3, the IFN- (IRF1, IRF3, IRF7, IFP35, Mx1) or inflammation-related (IL-1β and TNFα) factors, as well as decreased the activities of NF-κB, ISRE and IFN-3. While knockdown of EcBAG3 decreased the transcripts of RGNNV CP gene and RdRp gene. Further studies showed that EcBAG3 knockdown impaired the expression level of autophagy factor LC3-Ⅱ, and promoted the expression level of Bax and BNIP3, inflammatory factors and interferon factors. These data indicate that EcBAG3 can affect viral infection through modulating virus-induced cell death, regulating the expression of IFN- and inflammation-related factors, which will be helpful to further explore the immune response of fish during viral infection.

    Toxic effects of waterborne cadmium exposure on hematological parameters, oxidative stress, neurotoxicity, and heat shock protein 70 in juvenile olive flounder, Paralichthys olivaceus

    Lee D.-C.Choi Y.J.Kim J.-H.
    8页
    查看更多>>摘要:? 2022 The AuthorsCadmium-induced toxicity can affect fish embryo development, ion homeostasis regulation, energy metabolism, maturation and growth, stress response, and immunity. However, studies on the toxic effects of cadmium exposure to aquatic animals, particularly olive flounder (Paralichthys olivaceus), are limited. In this study, juvenile P. olivaceus (mean length, 12.9 ± 1.3 cm; mean weight, 23.1 ± 3.2 g) was exposed to waterborne cadmium (0, 50, 100, 200, and 400 μg/L) for 10 d. Hematological parameters, including hematocrit value and hemoglobin level, in P. olivaceus were significantly decreased after waterborne cadmium exposure. Plasma components such as calcium, glucose, cholesterol, glutamic-oxaloacetic transaminase, and glutamic-pyruvic transaminase were significantly altered via cadmium exposure. The activities of antioxidant enzymes, such as superoxide dismutase, catalase, and glutathione S-transferase, were significantly altered in P. olivaceus after cadmium exposure. Acetylcholinesterase activity was significantly inhibited upon waterborne cadmium exposure. Hepatic heat shock protein 70 was significantly upregulated in P. olivaceus after waterborne cadmium exposure. Therefore, waterborne cadmium at concentrations of >100 or 200 μg/L can induce physiological toxicity in P. olivaceus via changes in hematological parameters, antioxidant enzymes, neurotransmitters, and stress indicators.

    EDCs trigger immune-neurotransmitter related gene expression, and cause histological damage in sensitive mud crab Macrophthalmus japonicus gills and hepatopancreas

    Kim W.-S.Kwak I.-S.
    11页
    查看更多>>摘要:? 2022 Elsevier LtdEndocrine-disrupting chemicals (EDCs), distributed at various concentrations in freshwater and marine ecosystems, affect the survival, reproduction, and behavior of wide ranges organisms. Most toxicology studies on EDCs have focused on the endocrine system of invertebrates, and research on invertebrate neurotransmitters is limited. In the present study, we investigated the expression of Macrophthalmus japonicus genes encoding γ-aminobutyric acid transporter subtype 2 (GAT-2) and glutamine synthetase (GS), which play important roles as neurotransmitters at synapses. We observed differences in the mRNA expression levels of GAT-2 and GS as well as histological changes in various tissues after exposure to bisphenol-A (BPA) and di-(2-ethylhexyl) phthalate (DEHP). The amino acid sequences of M. japonicus GAT-2 and GS formed separate branches in crustaceans, fish, insects, and mammals. M. japonicus GAT-2 and GS expression levels were highest in the gills, hepatopancreas, and stomach, and showed different between DEHP or BPA treatments. In particular, hepatopancreas GS expression on Day 1, the first step in the presynaptic process, was upregulated after BPA and DEHP exposure, while GAT-2, sequential step in the presynaptic process, was significantly elevated only in DEHP. After BPA treatments, gill GS expression was increased at all concentrations, whereas GAT-2 expression was overall down regulations. In contrast, in DEHP treatment groups hepatopancreatic GS and GAT-2 expression at Day 1 was only significantly higher and all groups including gill GS and GAT-2 expression were downregulation. Histological changes in the gills and hepatopancreas were observed in a concentration-dependent manner. Accordingly, BPA and DEHP exposure in crabs could be stimulate neurotransmitter gene expression and alter the morphological structure of gill and hepatopancreas.