ALBERT

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Xing-Wei Xiang, Jin-Xing Xiao, Yu-Fang Zhou, Bin Zheng, Zheng-Shun Wen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The black seabream (〈em〉Sparus macrocephlus〈/em〉) is an economically pivotal aquaculture species cultured in China and Southeast Asian countries. To understand the molecular immune mechanisms underlying the response to 〈em〉Vibrio parahaemolyticus〈/em〉, a comparative gene transcription analysis were performed with utilized fresh livers of 〈em〉V. parahaemolyticus〈/em〉-immunized 〈em〉Sparus macrocephlus〈/em〉 with a control group through RNA-Seq technology. A total of 256663 contigs were obtained after excluded the low-quality sequences and assembly. The average length of contigs collected from this research is 1066.93 bp. Furthermore, blast analysis indicates 30747 contigs were annotated based on homology with matches in the NT, NR, gene, and string databases. A gene ontology analysis was employed to classify 21598 genes according to three major functional categories: molecular function, cellular component, and biological process. A total of 14470 genes were discovered in 303 KEGG pathways. RSEM and EdgeR were introduced to estimate 3841 genes significantly different expressed (False Discovery Rate〈0.001) which includes 4072 up-regulated genes and 3771 down-regulated genes. A significant enrichment analysis of these differentially expressed genes and isogenes were conducted to reveal the major immune-related pathways which refer to the toll-like receptor, complement, coagulation cascades, and chemokine signaling pathways. In addition, 92175 potential simple sequence repeats (SSRs) and 121912 candidate single nucleotide polymorphisms (SNPs) were detected and identified sequencely in the 〈em〉Sparus macrocephlus〈/em〉 liver transcriptome. This research characterized a gene expression pattern for normal and the 〈em〉V. parahaemolyticus〈/em〉 -immunized 〈em〉Sparus macrocephlus〈/em〉 for the first time and not only sheds new light on the molecular mechanisms underlying the host-〈em〉V. parahaemolyticus〈/em〉 interaction but contribute to facilitate future studies on 〈em〉Sparus macrocephlus〈/em〉 gene expression and functional genomics.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Yi-Hong Chen, Jian-Guo He〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The shrimp aquaculture industry is plagued by disease. Due to the lack of deep understanding of the relationship between innate immune mechanism and environmental adaptation mechanism, it is difficult to prevent and control the diseases of shrimp. The shrimp innate immune system has received much recent attention, and the functions of the humoral immune response and the cellular immune response have been preliminarily characterized. The role of environmental stress in shrimp disease has also been investigated recently, attempting to clarify the interactions among the innate immune response, the environmental stress response, and disease. Both the innate immune response and the environmental stress response have a complex relationship with shrimp diseases. Although these systems are important safeguards, allowing shrimp to adapt to adverse environments and resist infection, some pathogens, such as white spot syndrome virus, hijack these host systems. As shrimp lack an adaptive immune system, immunization therapy cannot be used to prevent and control shrimp disease. However, shrimp diseases can be controlled using ecological techniques. These techniques, which are based on the innate immune response and the environmental stress response, significantly reduce the impact of shrimp diseases. The object of this review is to summarize the recent research on shrimp environmental adaptation mechanisms, innate immune response mechanisms, and the relationship between these systems. We also suggest some directions for future research.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Yinnan Mu, Shimin Zhou, Ning Ding, Jingqun Ao, Xinhua Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Chemokines are a superfamily of structurally related chemotactic cytokines exerting significant roles in regulating cell migration and activation. Currently, five subgroups of fish specific CXC chemokines, named CXCL_F1-CXCL_F5, have been identified in teleost fish. However, understanding of the functions of these fish specific CXC chemokines is still limited. Here, a new member of fish specific CXC chemokines, 〈em〉Lc〈/em〉CXCL_F6, was cloned from large yellow croaker 〈em〉Larimichthys crocea〈/em〉. Its open reading frame (ORF) is 369 nucleotides long, encoding a peptide of 122 amino acids (aa). The deduced 〈em〉Lc〈/em〉CXCL_F6 protein contains a 19-aa signal peptide and a 103-aa mature polypeptide, which has four conserved cysteine residues (C〈sup〉28〈/sup〉, C〈sup〉30〈/sup〉, C〈sup〉56〈/sup〉, and C〈sup〉72〈/sup〉), as found in other known CXC chemokines. Phylogenetic analysis showed 〈em〉Lc〈/em〉CXCL_F6 formed a separate clade with sequences from other fish species, tentatively named CXCL_F6, distinct from the clades formed by fish CXCL_F1-5 and mammalian CXC chemokines. The 〈em〉Lc〈/em〉CXCL_F6 transcripts were constitutively expressed in all examined tissues and significantly up-regulated in the spleen and head kidney tissues by poly (I:C) and 〈em〉Vibrio alginolyticus〈/em〉. Its transcripts were also detected in primary head kidney leukocytes (HKLs), peripheral blood leucocytes (PBLs), and large yellow croaker head kidney (LYCK) cell line, and significantly up-regulated by poly(I:C), lipopolysaccharide (LPS), and peptidoglycan (PGN) in HKLs. Recombinant 〈em〉Lc〈/em〉CXCL_F6 protein (r〈em〉Lc〈/em〉CXCL_F6) could not only chemotactically attract monocytes/macrophages and lymphocytes from PBLs, but also enhance NO release and expression of proinflammatory cytokines (TNF-α, IL-1β, and CXCL8) in monocytes/macrophages. These results indicate that 〈em〉Lc〈/em〉CXCL_F6 plays a role in mediating the inflammatory response.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Jinghua Chen, Lu Zhang, Ning Yang, Mengyu Tian, Qiang Fu, Fenghua Tan, Chao Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Galectins are a family of galactoside-binding proteins with an affinity for β-galactosides, involved in mediating fundamental processes including development, inflammation, cell migration and apoptosis. Galectin-4 is a member of tendem-repeat galectins, plays vital roles in intestinal epithelial barrier. Here, one galectin-4 gene was captured in turbot (〈em〉Sm〈/em〉Lgals4) contains a 1197 bp open reading frame (ORF). In comparison to other species, 〈em〉Sm〈/em〉Lgals4 showed the highest similarity and identity both to large yellow croaker. The genomic structure analysis showed that 〈em〉Sm〈/em〉Lgals4 had conserved exons in the CRD domains compared to other vertebrate species. The syntenic analysis revealed that galectin-4 had the same neighboring genes across all the selected species, which suggested the synteny encompassing galectin-4 region during vertebrate evolution. Subsequently, 〈em〉Sm〈/em〉Lgals4 was widely expressed in all the examined tissues, with the highest expression level in intestine and the lowest expression level in skin. In addition, 〈em〉Sm〈/em〉Lgals4 was significantly down-regulated in intestine following both Gram-negative bacteria 〈em〉Vibrio anguillarum〈/em〉, and Gram-positive bacteria 〈em〉Streptococcus iniae〈/em〉 immersion challenge. Finally, the 〈em〉rSm〈/em〉Lgals4 showed strong binding ability to all the examined microbial ligands. Taken together, our results suggested 〈em〉Sm〈/em〉Lgals4 plays vital roles in fish intestinal immune responses against infection, but the detailed roles of galectin-4 in teleost are still lacking, further studies are needed to be carried out to characterize whether galectin-4 plays similar roles in teleost intestinal immunity.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Yanxiu Mo, Yunpeng Fan, Wen Fu, Wenting Xu, Shujuan Chen, Yuanhui Wen, Shaojun Liu, Liangyue Peng, Yamei Xiao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Previous research has indicated that the small compound, SP600125, could induce polyploidy of fish cells, and has established a stable tetraploid cell line from diploid fish cells. In order to explore how fish cells maintain homeostasis under SP600125-stress 〈em〉in vitro〈/em〉, this study investigates impacts of SP600125-stress on intracellular pathways, as well as on regulation of the cellular homeostasis feedback in fish cells. Transcriptomes are obtained from the SP600125-treated cells. Compared with unigenes expressed in control group (crucial carp fin cells), a total of 2670 and 1846 unigenes are significantly upregulated and downregulated in these cells, respectively. Differentially expressed genes are found, which are involved in innate defense, inflammatory pathways and cell adhesion molecules-related pathways. The SP600125-stress enhances cell-mediated immunity, characterized by significantly increasing expression of multiple immune genes. These enhanced immune genes include the pro-inflammatory cytokines (IL-1β, TNF-ɑ, IL-6R), the adaptor signal transducers (STAT, IκBɑ), and the integrins (ɑ2β1, ɑMβ2). Furthermore, mitochondria are contributed to the cellular homeostasis regulation upon the SP600125-stress. The results show that acute inflammation is an adaptive and controlled response to the SP600125-stress, which is beneficial for alleviating toxicity by SP600125. They provide a potential way of breeding fish polyploidy induced by SP600125 in the future research.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Maciej Woźny, Kazimierz Obremski, Piotr Hliwa, Piotr Gomułka, Rafał Różyński, Paweł Wojtacha, Maciej Florczyk, Helmut Segner, Paweł Brzuzan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To investigate the effects of feed contamination with zearalenone (ZEN) at the current European Commission (EC) guidance value (2 mg⋅kg〈sup〉−1〈/sup〉 feed) on the growth and health of rainbow trout, we performed a long-term feeding trial under aquaculture conditions. It started with the external feeding of the fish larvae, and continued for 96 weeks, at which point the fish had reached market size. To assess the growth of fish and their feeding efficiency throughout this period, the fish were regularly weighed and measured, and their feed consumption was monitored. Additionally, to investigate potential health effects, after 72 weeks of the exposure to ZEN, the fishes' blood was analyzed for major hematological and biochemical indices, and their head kidney, spleen, and liver were examined for morphological, histopathological, cytological, and molecular changes. Finally, to gain insight into the metabolism and distribution of ZEN in fish, the content of free and glucuronidated forms of ZEN and its major metabolites was measured in the intestine, liver, and muscles of the exposed fish. The feed-borne exposure of rainbow trout to ZEN at a dose of 2 mg⋅kg〈sup〉−1〈/sup〉 feed resulted in higher feeding efficiency and growth rate, most probably due to the anabolic properties of the ZEN metabolite. Importantly for the consumers of fish, despite absorption and metabolism of ZEN in the digestive system of the fish that had been exposed for 72 weeks, the residuals of ZEN were not transferred to the fishes’ muscles, which rules out a potential risk to human health related to the consumption of fish meat. However, the increased growth of fish fed with the contaminated feed may come at some cost, as the exposure to ZEN was associated with modulation of key components of the adaptive and innate immune systems. Moreover, the trunk kidney of ZEN-fed fish showed massive inflammation that was likely caused by pathogen infection. These findings raise concerns about fish health under the current recommended EC guidance values.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Xin Cai, Chengbin Gao, Huanhuan Song, Ning Yang, Qiang Fu, Fenghua Tan, Chao Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Cathepsin Z (CTSZ) is a lysosomal cysteine protease of the papain superfamily. It participates in the host immune defense via phagocytosis, signal transduction, cell-cell communication, proliferation, and migration of immune cells such as monocytes, macrophages, and dendritic cells. In this study, we reported the identification of 〈em〉Sm〈/em〉CTSZ, a CTSZ homolog from turbot (〈em〉Scophthalmus maximus〈/em〉 L.). 〈em〉Sm〈/em〉CTSZ was 317 residues in length and contains a Pept-C1 domain. In multiple species comparison, 〈em〉Sm〈/em〉CTSZ shared 65–93% overall sequence identities with the CTSZ counterparts from human, rat, and several fish species. In the phylogenetic analysis, 〈em〉Sm〈/em〉CTSZ showed the closest relationship to 〈em〉Cynoglossus semilaevis〈/em〉. The syntenic analysis revealed the similar neighboring genes of CTSZ across all the selected species, which suggested the synteny encompassing CTSZ region during vertebrate evolution. Subsequently, 〈em〉Sm〈/em〉CTSZ was constitutively expressed in various tissues, with the lowest and highest levels in brain and intestine respectively. In addition, 〈em〉Sm〈/em〉CTSZ was significantly up-regulated in intestine following both Gram-negative bacteria 〈em〉Vibrio anguillarum〈/em〉, and Gram-positive bacteria 〈em〉Streptococcus iniae〈/em〉 immersion challenge. Finally, the 〈em〉rSm〈/em〉CTSZ showed strong binding ability to all the examined microbial ligands, and the agglutination effect to different bacteria. Taken together, these results indicated 〈em〉Sm〈/em〉CTSZ could play important roles in mucosal immune response in the event of bacterial infection in teleost. However, the knowledge of CTSZ are still limited in teleost species, further studies should be carried out to better characterize its detailed roles in teleost mucosal immunity.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Zhi Zhou, Zhaoqun Liu, Lingui Wang, Jian Luo, Hailang Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Giant clams are one of the most important animals in coral reef ecosystem, and its growth and reproduction are being threatened by heat stress due to global warming. In the present study, the symbiont density, the crucial enzyme activities and the transcriptome were investigated in the outer mantle of giant clam 〈em〉Tridacna crocea〈/em〉 after the acute exposure of high temperature. The density of symbiotic zooxanthellae decreased significantly during 12–24 h, with the minimum level (7.75 × 10〈sup〉5〈/sup〉 cell cm〈sup〉−2〈/sup〉, 〈em〉p〈/em〉 〈 0.05) at 12 h after heat stress. The activities of superoxide dismutase in the heat stress group was significantly lower than that in the control group at 24 h after heat stress, while no significant change in the activities of catalase was observed during the entire stress process. The activation level of caspase3 began to increase significantly at 12 h (1.22-fold, 〈em〉p〈/em〉 〈 0.05), and reached the highest level at 24 h (1.38-fold, 〈em〉p〈/em〉 〈 0.05) after heat stress. Six paired-end libraries were sequenced in two groups, including the heat stress and control group at 12 h after heat stress. Through the assembling of 187,116,632 paired-end reads with lengths of 2 × 150 bp, a total of 26,676 genes were obtained which derived from giant clam. Bioinformatics analysis revealed 47 significantly upregulated and 88 significantly downregulated genes at 12 h after the treatment. There were 12 overrepresented GO terms for significantly upregulated genes, mostly related to unfolded protein binding and ATP binding, whereas no GO term was overrepresented for significantly downregulated genes. These results collectively suggest high temperature could induce excessive oxidative stress through the repressed antioxidant ability, the apoptosis activated by the unfolded protein response, and further the collapse of the symbiosis between host and symbiont, which has been threatening the growth and reproduction of the giant clam 〈em〉T. crocea〈/em〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Zhi-qiang Du, Yue Wang, Hong-yu Ma, Xiu-li Shen, Kai Wang, Jie Du, Xiao-dong Yu, Wen-hong Fang, Xin-cang Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Crustins play important roles in defending against bacteria in the innate immunity system of crustaceans. In present study, we identified a crustin gene in 〈em〉Scylla paramamosain〈/em〉, which was named as 〈em〉SpCrus6〈/em〉. The ORF of 〈em〉Sp〈/em〉Crus6 possessed a signal peptide sequence (SPS) at the N-terminus and a WAP domain at the C-terminus. And there were 5 Proline residues, 5 Glycine and 4 Cysteine residues between SPS and WAP domain in 〈em〉Sp〈/em〉Crus6. These features indicated that 〈em〉Sp〈/em〉Crus6 was a new member of crustin family. The 〈em〉SpCrus6〈/em〉 mRNA transcripts were up-regulated obviously after bacteria or virus challenge. These changes showed that 〈em〉SpCrus6〈/em〉 was involved in the antimicrobial and antiviral responses of 〈em〉Scylla paramamosain〈/em〉. Recombinant 〈em〉Sp〈/em〉Crus6 (r〈em〉Sp〈/em〉Crus6) showed strong inhibitory abilities against Gram-positive bacteria (〈em〉Bacillus megaterium〈/em〉, 〈em〉Staphylococcus aureus〈/em〉, and 〈em〉Bacillus subtilis〈/em〉). But the inhibitory abilities against four Gram-negative bacteria (〈em〉Vibrio parahemolyticus〈/em〉, 〈em〉Vibrio alginolyticus〈/em〉, 〈em〉Vibrio harveyi〈/em〉 and 〈em〉Escherichia coli〈/em〉) and two fungi (〈em〉Pichia pastoris〈/em〉 and 〈em〉Candida albicans〈/em〉) were not strong enough. Besides, r〈em〉Sp〈/em〉Crus6 could strongly bind to two Gram-positive bacteria (〈em〉B〈/em〉. 〈em〉subtilis〈/em〉 and 〈em〉B〈/em〉. 〈em〉megaterium〈/em〉) and three Gram-negative bacteria (〈em〉V〈/em〉. 〈em〉alginolyticus〈/em〉, 〈em〉V〈/em〉. 〈em〉parahemolyticus〈/em〉, and 〈em〉V〈/em〉. 〈em〉harveyi〈/em〉). And the binding levels to 〈em〉S. aureus〈/em〉 and two fungi (〈em〉P〈/em〉. 〈em〉pastoris〈/em〉 and 〈em〉C〈/em〉. 〈em〉albicans〈/em〉) were weak. The polysaccharides binding assays’ results showed r〈em〉Sp〈/em〉Crus6 had superior binding activities to LPS, LTA, PGN and 〈em〉β〈/em〉-glucan. Through agglutinating assays, we found r〈em〉Sp〈/em〉Crus6 could agglutinate well three Gram-positive bacteria (〈em〉S〈/em〉. 〈em〉aureus〈/em〉, 〈em〉B〈/em〉. 〈em〉subtilis〈/em〉 and 〈em〉B〈/em〉. 〈em〉megaterium〈/em〉). And the agglutinating activities to Gram-negative bacteria and fungi were not found. In the aspect of antiviral functions, r〈em〉Sp〈/em〉Crus6 could bind specifically to the recombinant envelop protein 26 (rVP26) of white spot syndrome virus (WSSV) but not to recombinant envelop protein 28 (rVP28), whereas GST protein could not bind to rVP26 or rVP28. Besides, r〈em〉Sp〈/em〉Crus6 could suppress WSSV reproduction to some extent. Taken together, 〈em〉Sp〈/em〉Crus6 was a multifunctional immunity effector in the innate immunity defending response of 〈em〉S〈/em〉. 〈em〉paramamosain〈/em〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Yunkun Li, Jiayu Wu, Dong Li, Anqi Huang, Guixian Bu, Fengyan Meng, Fanli Kong, Xiaohan Cao, Xingfa Han, Xiaofu Pan, Wei Fan, Shiyong Yang, Xianyin Zeng, Xiaogang Du〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉〈em〉Schizothorax prenanti〈/em〉 (〈em〉S. prenanti〈/em〉), an important species of economical fish in Southwest China, is susceptible to 〈em〉Aeromonas hydrophila〈/em〉 (Ah). To understand the immune response to Ah, the transcriptome profiling of spleen of 〈em〉S. prenanti〈/em〉 was analyzed after Ah infection. A total of 6, 213 different expression genes (DEGs) were obtained, including 3, 066 up-regulated DEGs and 3, 147 down-regulated DEGs. These DEGs were annotated by KEGG and GO databases, so that the immune-related DEGs (IRDs) can be identified and classified. Then, the interesting IRDs were screened to build heat map, and the reliability of the transcriptome data was validated by qPCR. In order to clarify the mechanism of signal transduction in the anti-bacterial immunity, the signaling pathway initiated by TLRs was predicted. In this pathway, TLR25 and TLR5 mediate the NF-κB and AP-1 signals via MyD88-dependent pathway. Meanwhile, the type I IFN (IFNα/β) induced by IRF1 and IRF3/7 may play an important role in the anti-bacterial immunity. In conclusion, this study preliminarily provides insights into the mechanism of signal transduction after Ah infection in 〈em〉S. prenanti〈/em〉, which contributes to exploring the complex anti-bacterial immunity.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Hongye Jiang, Qing Bian, Weiwei Zeng, Pengli Ren, Hengchang Sun, Zhipeng Lin, Zeli Tang, Xinyi Zhou, Qing Wang, Yingying Wang, Yensheng Wang, Mei X. Wu, Xuerong Li, Xinbing Yu, Yan Huang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Grass carp (〈em〉Ctenopharyngodon idellus〈/em〉) hemorrhagic disease (GCHD), caused by grass carp reovirus (GCRV), has given rise to an enormous loss in grass carp industry during the past years. Up to date, vaccination remained to be the most effective way to protect grass carp from GCHD. Oral vaccination is of major interest due to its advantages of noninvasive, time-saving, and easily-operated. The introduction of oral vaccination has profound impact on aquaculture industry because of its feasibility of extensive application for fish in various size and age. However, the main challenge in developing oral vaccine is that antigens are easily degraded and are easy to induce tolerance. 〈em〉Bacillus subtilis〈/em〉 (〈em〉B. subtilis〈/em〉) spores would be an ideal oral vaccine delivery system for their robust specialty, gene operability, safety and adjuvant property. VP4 protein is the major outer capsid protein encoded by GCRV segment 6 (S6), which plays an important role in viral invasion and replication. In this study, we used 〈em〉B. subtilis〈/em〉 spores as the oral delivery system and successfully constructed the 〈em〉B. subtilis〈/em〉 CotC-VP4 recombinant spores (CotC-VP4 spores) to evaluate its protective efficacy in grass carp. Grass carp orally immunized with CotC-VP4 spores showed a survival rate of 57% and the relative percent survival (RPS) of 47% after the viral challenge. Further, the specific IgM levels in serum and the specific IgZ levels in intestinal mucus were significantly higher in the CotC-VP4 group than those in the Naive group. The immune-related genes including three innate immune-related genes (IL-4/13A, IL-4/13B, CSF1R), four adaptive immune-related genes (BAFF, CD4L, MHC-II, CD8), three inflammation-related genes (IL-1β, TNF-α, TGF-β) and interferon type I (IFN-I) related signaling pathway genes were significantly up-regulated in the CotC-VP4 group. The study demonstrated that the CotC-VP4 spores produced protection in grass carp against GCRV infection, and triggered both innate and adaptive immunity post oral immunization. This work highlighted that 〈em〉Bacillus subtilis〈/em〉 spores were powerful platforms for oral vaccine delivery, and the combination of 〈em〉Bacillus subtilis〈/em〉 spores with GCRV VP4 protein was a promising oral vaccine.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Guang-hua Wang, Jing-jing Wang, Bin Yue, Xue Du, He-he Du, Min Zhang, Yong-hua Hu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉High-mobility group box 2 (HMGB2) is a non-histone chromosomal protein that involved diverse functions such as transcriptional regulation and innate immune responses in mammalian. In teleost, very limited studies on HMGB2 proteins have been documented. Black rockfish (〈em〉Sebastes schlegelii〈/em〉) is an economic fish species and cultured worldwide. However, the study of black rockfish about immunology is very scarce. In the present study, a HMGB2 homologue gene (〈em〉SsHMGB2〈/em〉) was identified and characterized in black rockfish. The open reading frame of 〈em〉SsHMGB2〈/em〉 is 648 bp, and the deduced amino acid sequence of 〈em〉SsHMGB2〈/em〉 shares 74.4%–91.2% overall sequence identities with the HMGB2 proteins of several fish species. In silico analysis identified several conserved features, including two basic HMG boxes and an acidic C-terminal tail composed of 24 Asp/Glu residues. Expression of 〈em〉SsHMGB2〈/em〉 occurred in multiple tissues and was upregulated during pathogens infection. Recombinant SsHMGB2 (rSsHMGB2) exhibited apparent binding activities against DNA. 〈em〉In vivo〈/em〉 studies showed that the expressions of multiple immune-related genes in head kidney were significantly enhanced when black rockfish were treated with rSsHMGB2. Furthermore, rSsHMGB2 reduced pathogen dissemination and replication in fish kidney and spleen. Taken together, these results suggest that SsHMGB2 possesses apparent immunoregulatory properties and played a role in fighting bacterial infection.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Sai-Wei Chen, Chun-Hung Liu, Shao-Yang Hu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bacteria-induced diseases are a major cause of mortality in aquaculture. Probiotics have commonly been used to replace antibiotics for prophylactic biocontrol in aquaculture. In the present study, 〈em〉Paenibacillus ehimensis〈/em〉 NPUST1 was isolated from a tilapia culture pond. This probiotic has bacteriocin-like activities against 〈em〉Aeromonas hydrophila〈/em〉 and was characterized by biochemical analysis and 16S rDNA sequencing. The physiochemical properties of a crude extract of the bacteriocin-like substance revealed low pH and high thermal tolerance. The substance exhibited broad-spectrum antimicrobial activity against diverse aquatic pathogens, food spoilage, clinical pathogens, and plant pathogens. The effect of dietary supplementation with 〈em〉P. ehimensis〈/em〉 NPUST1 was evaluated in regard to the growth of Nile tilapia (〈em〉Oreochromis niloticus〈/em〉) and immunity against pathogenic infection. The results showed significantly increased weight gain (WG), feed conversion ratio (FCR), and feed efficiency (FE) in Nile tilapia fed 〈em〉P. ehimensis〈/em〉 NPUST1 for 2 months compared with fish fed a control diet. When challenged with 〈em〉A. hydrophila〈/em〉 and 〈em〉S. iniae,〈/em〉 the fish fed 〈em〉P. ehimensis〈/em〉 NPUST1 also exhibited a higher survival rate than fish fed the control diet. The immune parameters revealed that the 〈em〉P. ehimensis〈/em〉 NPUST1-fed fish had significantly higher phagocytic activity, respiratory burst, and superoxide dismutase (SOD) of the head kidney leukocytes, as well as higher serum lysozyme activity and expression of cytokines TNF-α and IL-1β than the fish fed the control diet. These results indicate that dietary supplementation with 〈em〉P. ehimensis〈/em〉 NPUST1 improved the growth performance, immunity, and disease resistance in Nile tilapia.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Cheng-cai Zheng, Xin-yi Cai, Meng-meng Huang, Idefonce Mkingule, Cong Sun, Shi-Chao Qian, Zhen-ju Wu, Bing-nan Han, Hui Fei〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Japanese eel (〈em〉Anguilla japonica〈/em〉) has become a commercially important fish species all over the world. High-density aquaculture has led to congestion and contributed to bacterial infection outbreaks that have caused high mortality. Therefore a 56-days feeding trial was conducted to determine the effects of dietary 〈em〉Bacillus amyloliquefaciens〈/em〉 (GB-9) and 〈em〉Yarrowia lipolytica〈/em〉 lipase2 (YLL2) on growth performance, digestive enzymes activity, innate immunity and resistance to pathogens of 〈em〉A. japonica〈/em〉. Fish growth performance was significantly affected by dietary YLL2 supplementation but not by GB-9. Fish fed diets with YLL2 at 2.0 g/kg diet in combination of high and low levels of GB-9 (5.0 g/kg and 2.0 g/kg) produced the highest growth. For digestive enzyme, lipase and trypsin activities was promoted by dietary containing YLL2, while amylase activities was increased by dietary containing YLL2, GB-9 single or combination. For innate immunity, the mucus lysozyme activity, leukocytes phagocytosis activity and reactive oxygen species level of skin, peroxidase and lysozyme activity of serum were enhanced in fish fed with GB-9 compared to those in control group (p 〈 0.05). The highest resistance to 〈em〉Vibrio anguillarum〈/em〉 and 〈em〉Aeromonas hydrophila〈/em〉 was determined in fish fed with 5.0 g kg〈sup〉−1〈/sup〉 GB-9 + 2.0 g/kg YLL2. This study demonstrated that GB-9 and YLL2 enhanced non-specific immune defense system of 〈em〉A. japonica〈/em〉, providing them with higher resistance to pathogens. The present results suggested that the combination of these supplements could be considered as potential biological additives for aquaculture farmed fish.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Xianyong Bu, Xuqiu Lian, Yi Wang, Chengzeng Luo, Shengqiang Tao, Yilu Liao, Jiaming Yang, Aijing Chen, Yuhong Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The aim of the present study was to investigate effects of dietary yeast culture on immune response related to TLR2-MyD88-NF-kβ signaling pathway, antioxidant capability and disease resistance against 〈em〉Aeromonas hydrophila〈/em〉 for Ussuri catfish (〈em〉Pseudobagrus ussuriensis〈/em〉). A total of 240 Ussuri catfish (mean weight of 7.39 ± 0.32 g) were randomly distributed into four groups that fed diets containing 0 (Y0), 10 (Y1), 20 (Y2) and 30 (Y3) g kg〈sup〉−1〈/sup〉 yeast culture for 8 weeks. The results indicated that dietary 10 g kg〈sup〉−1〈/sup〉 yeast culture supplementation significantly down-regulated mRNA levels of TLR2, MyD88, NF-kβ p65, IL-1β and IL-8 in the liver tissue compared with the control group (〈em〉P〈/em〉 〈 0.05). Simultaneously, serum lysozyme (LZM) activity, respiratory burst activity (RBA) of phagocytes, plasma alkaline phosphatase (AKP) activity and immunoglobulin M (IgM) content were significantly improved in fish fed Y1 diet (〈em〉P〈/em〉 〈 0.05). Fish fed Y1 diet had significantly higher serum alternative complement pathway activity (ACH50) and plasma complement 3 (C3) content than the Y3 group (〈em〉P〈/em〉 〈 0.05). However, no significant differences were observed in plasma acid phosphatase (ACP) activity and complement 4 (C4) content among the groups (〈em〉P〈/em〉 〉 0.05). Fish cumulative mortality rate (CMR) in the Y1 and Y2 groups were significantly lower than that in Y0 and Y3 groups (〈em〉P〈/em〉 〈 0.05), and the lowest CMR was observed in the Y1 group after challenge by 〈em〉A. hydrophila〈/em〉. The highest hepatic superoxide dismutase and glutathione peroxidase activities, total antioxidant capacity and the lowest malondialdehyde content were found in Y1 group, but no significant difference was found in hepatic catalase activity among the groups (〈em〉P〈/em〉 〉 0.05). These results demonstrate that dietary 10 g kg〈sup〉−1〈/sup〉 yeast culture could effectively improve the immunity, antioxidant capability and disease resistance against 〈em〉A. hydrophila〈/em〉 for Ussuri catfish and could down-regulate the mRNA expression levels of pro-inflammatory cytokines modulated by TLR2-MyD88-NF-kβ signaling pathway.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Tao Wang, Xin Wen, Yadong Hu, Xinyu Zhang, Dan Wang, Shaowu Yin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Copper nanoparticles (Cu NPs) are a new pollutant in aquaculture, representing a hazard to aquatic organisms. We investigated the effects of Cu NPs exposure on oxidative stress, apoptosis and immune response in an economically important model species, 〈em〉Takifugu fasciatus〈/em〉. The juvenile fish were exposed to control, 20 or 100 μg Cu NPs/L for 30 days. The growth of 〈em〉T. fasciatus〈/em〉 was inhibited after Cu NPs exposure. Copper accumulation in liver increased with increasing Cu NPs dose. Oxidative stress indicators [malondialdehyde (MDA), total superoxide dismutase (T-SOD), catalase (CAT) and glutathione (GSH)], apoptosis index and activities of caspases (caspase-3, caspase-9) were all increased with the increase of Cu NPs concentration in liver. With an increase in Cu NPs dose, the activities of succinate dehydrogenase (SDH) and Na〈sup〉+〈/sup〉-K〈sup〉+〈/sup〉-ATPase as well as cytochrome c (Cyt-c) concentration in mitochondria decreased, accompanied by increased Cyt-c concentration in cytosol. Apoptosis-related gene expressions of 〈em〉p53〈/em〉, 〈em〉caspase-3〈/em〉, 〈em〉caspase-9〈/em〉 and 〈em〉Bax〈/em〉 were increased with the increase of Cu NPs dose. However, the opposite result was found in 〈em〉Bcl2〈/em〉 expression. The physiological indicators of immune response [heat shock protein 70 (HSP70), heat shock protein 90 (HSP90), immunoglobulin M (IgM) and lysozyme (LZM)] as well as the mRNA levels of 〈em〉HSP70〈/em〉, 〈em〉HSP90〈/em〉, 〈em〉IgM〈/em〉 and 〈em〉C-LZM〈/em〉 were all increased after Cu NPs exposure〈em〉.〈/em〉 Our results will be helpful in understanding the mechanism of Cu NPs toxicity in 〈em〉T. fasciatus〈/em〉.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1050464818306867-fx1.jpg" width="278" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Junguo Ma, Xi Chen, Guangyuan Xin, Xiaoyu Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present study aimed to determine the chronic toxicity of 1-methyl-3-octylimidazolium bromide ([C〈sub〉8〈/sub〉mim]Br) on the silver carp to further reveal the toxicological mechanisms of ionic liquids. Chronic exposure of silver carp to [C〈sub〉8〈/sub〉mim]Br at concentrations of 1.095 and 4.380 mg/L for 60 d was conducted under laboratory conditions. The results revealed that chronic exposure to [C〈sub〉8〈/sub〉mim]Br inhibited the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) and reduced glutathione (GSH) levels while markedly increasing malondialdehyde (MDA) and protein carbonyl (PC) levels in fish spleen, indicating that [C〈sub〉8〈/sub〉mim]Br treatment induced oxidative stress. Additionally, long-term exposure to [C〈sub〉8〈/sub〉mim]Br markedly upregulated the expressions of nuclear factor-κB (NF-κB), inducible nitric oxide synthase (iNOS), interleukin-1β (IL-1β), IL-6, tumour necrosis factor-α (TNF-α), and interferon-γ (IFN-γ); altered the levels of transforming growth factor-β (TGF-β); and increased the mRNA levels of p38MAPK, c-fos, c-jun, and c-myc, suggesting that long-term exposure to [C〈sub〉8〈/sub〉mim]Br might promote the inflammatory response in fish spleen and that p38MAPK/NF-κB signalling may potentially be involved in this process. Moreover, [C〈sub〉8〈/sub〉mim]Br-exposure altered lysozyme activity and complement 3 (C3) and immunoglobulin M (IgM) content, indicating that chronic [C〈sub〉8〈/sub〉mim]Br exposure also has immunotoxic effects on silver carp. Furthermore, we also found that [C〈sub〉8〈/sub〉mim]Br exposure reduced miR-125b levels, altered miR-143 levels, and upregulated miR-155 and miR-21 levels, suggesting that these miRNAs may be involved in the [C〈sub〉8〈/sub〉mim]Br-induced inflammatory response in fish spleen. In summary, the present study indicates that chronic exposure to [C〈sub〉8〈/sub〉mim]Br induces inflammation in fish spleen and that oxidative stress-mediated p38MAPK/NF-κB signalling and miRNAs may play a key role in this process.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Chaozheng Li, Shaoping Weng, Jianguo He〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As invertebrates, shrimps rely on multiple innate defense reactions, including humoral immunity and cellular immunity to recognize and eliminate various invaders, such as viruses. White spot syndrome virus (WSSV) causes the most prevalent and devastating viral disease in penaeid shrimps, which are the most widely cultured species in the coastal waters worldwide. In the last couple of decades, studies about WSSV implicate a dual role of the immune system in protecting shrimps against the infection; these studies also explore on the pathogenesis of WSSV infection. Herein, we review our current knowledge of the innate immune responses of shrimps to WSSV, as well as the molecular mechanisms used by this virus to evade host immune responses or actively subvert them for its own benefit. Deciphering the interactions between WSSV and the shrimp host is paramount to understanding the mechanisms that regulate the balance between immune-mediated protection and pathogenesis during viral infection and to the development of a safe and effective WSSV defensive strategy.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Xin Zhang, Jialong Shi, Yulong Sun, Yusuf Jibril Habib, Huiping Yang, Ziping Zhang, Yilei Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In recent years, the abalone aquaculture industry has been threatened by the deteriorating environmental conditions, such as hypoxia and thermal stress in the hot summers. It is necessary to investigate the molecular mechanism in response to these environmental challenges, and subsequently understand the immune defense system. In this study, the transcriptome profiles by RNA-seq of hemocytes from the small abalone 〈em〉Haliotis diversicolor〈/em〉 after exposure to hypoxia, thermal stress, and hypoxia plus thermal stress were established. A total of 103,703,074 clean reads were obtained and 99,774 unigenes were assembled. Of the 99,774 unigenes, 47,154 and 20,455 had homologous sequences in the Nr and Swiss-Prot protein databases, while 16,944 and 10,840 unigenes could be classified by COG or KEGG databases, respectively. RNAseq analysis revealed that the differentially expressed genes (DEGs) after challenges of hypoxia, thermal stress, or hypoxia plus thermal stress were 24,189, 29,165 and 23,665, among which more than 3000 genes involved in at least 230 pathways, including several classical immune-related pathways. The genes and pathways that were involved in immune response to hypoxia/thermal challenges were identified by transcriptome analysis and further validated by quantitative real-time PCR and RNAi technology. The findings in this study can provide information on 〈em〉H. diversicolor〈/em〉 innate immunity to improve the abalone aquaculture industry, and the analysis of the potential immune-related genes in innate immunity signaling pathways and the obtained transcriptome data can provide an invaluable genetic resource for the study of the genome and functional genes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Thanthrige Thiunuwan Priyathilaka, S.D.N.K. Bathige, Seongdo Lee, Bo-Hye Nam, Jehee Lee〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Toll-like receptors (TLRs) are well-known pattern recognition receptors that play key immunological roles in a diverse range of organisms. In this study, two novel invertebrate TLRs from disk abalone (designated as AbTLR-A and AbTLR-B) were identified and functionally characterized for the first time. AbTLR-A and AbTLR-B comprised the typical TLR domain architecture containing an extracellular leucine-rich repeat domain, transmembrane domain, and Toll/interleukin-1 receptor domain. Expressional analysis revealed that both TLRs were constitutively expressed at all the early embryonic stages of disk abalone analyzed, with the highest level of 〈em〉AbTLR-A〈/em〉 found at the 16-cell stage and 〈em〉AbTLR-B〈/em〉 at the trochophore stage. According to tissue distribution analysis, prominent mRNA expression of 〈em〉AbTLR-A〈/em〉 and 〈em〉AbTLR-B〈/em〉 was detected in the hemocytes and gills, respectively. 〈em〉AbTLR-A〈/em〉 and 〈em〉AbTLR-B〈/em〉 mRNAs were significantly up-regulated in response to Gram-negative 〈em〉Vibrio parahemolyticus〈/em〉, Gram-positive 〈em〉Listeria monocytogenes〈/em〉, and viral hemorrhagic septicemia virus injections in abalone hemocytes and gills. Overexpression of AbTLR-A and AbTLR-B in HEK293T cells directly activated nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) responsive reporters. Neither TLRs showed a high response to pathogen-associated molecular patterns 〈em〉in vitro〈/em〉. Co-expression of AbTLR-A and AbTLR-B with AbMyD88-2 and AbMyD88-X activated NF-κB-responsive reporters in a synergetic manner. These findings demonstrate the involvement of AbTLR-A and AbTLR-B in abalone innate immunity.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Mona Saleh, Gokhlesh Kumar, Abdel-Azeem S. Abdel-Baki, Mohamed A. Dkhil, Mansour El-Matbouli, Saleh Al-Quraishy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉〈em〉Ichthyophthirius multifiliis〈/em〉, a ciliated protozoan parasite, causes ichthyophthiriasis and leads to considerable economic losses to the aquaculture industry. Understanding the fish immune response and host-parasite interactions could support developing novel strategies for better disease management and control. Fish skin mucus is the first line of defence against infections through the epidermis. Yet, the common carp, 〈em〉Cyprinus carpio〈/em〉, protein-based defence strategies against infection with 〈em〉I. multifiliis〈/em〉 at this barrier remain elusive. The skin mucus proteome of common carp was investigated at 1 day and 9 days post-exposure with 〈em〉I. multifiliis〈/em〉. Using nano-LC ESI MS/MS and statistical analysis, the abundance of 19 immune related and signal transduction proteins was found to be differentially regulated in skin mucus of common carp in response to 〈em〉I. multifiliis〈/em〉. The analysis revealed increased abundance values of epithelial chloride channel protein, galactose-specific lectin nattection, high choriolytic enzyme 1 (nephrosin), lysozyme C, granulin and protein-glutamine gamma-glutamyltransferase 2 in 〈em〉I. multifiliis-〈/em〉exposed carp skin mucus. Multiple lectins and a diverse array of distinct serpins with protease inhibitor activity were identified likely implicated in lectin pathway activation and regulation of proteolysis, indicating that these proteins contribute to the carp innate immune system and the protective properties of skin mucus. The results obtained from this proteomic analysis enables a better understanding of fish host response to parasitic infection and gives insights into the key role skin mucus plays in protecting fish against deleterious effects of 〈em〉I. multifiliis〈/em〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Fufa Qu, Jianzhou Tang, Jinting Liao, Bei Chen, Peng Song, Wenjie Luo, Ding Xiong, Tianting Liu, Qianting Gao, Shuangqing Lu, Zhen Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mitogen-activated protein kinase kinase 6 (MKK6) is an essential component of the p38MAPK signaling pathway, which is involved in the modulation of inflammation, cell apoptosis and survival responses in mammals. However, the function of MKK6s in teleosts is still unclear. In this study, a fish MKK6 homolog (〈em〉Ci〈/em〉MKK6) was first identified from the grass carp (〈em〉Ctenopharyngodon idella〈/em〉), a freshwater fish. 〈em〉Ci〈/em〉MKK6 cDNA encodes a putative protein of 357 amino acids that contains conserved structural characteristics of the MKK6 family, including the S_TKc domain, SVAKT motif and DVD site. The deduced 〈em〉Ci〈/em〉MKK6 protein exhibits high sequence homology with other reported fish MKK6s and shares the closest relationship with MKK6 from 〈em〉Danio rerio〈/em〉. Quantitative real-time PCR (qRT-PCR) analysis revealed that 〈em〉Ci〈/em〉MKK6 mRNA was widely expressed in all tested tissues and stages of embryonic development. Additionally, the transcript levels of 〈em〉Ci〈/em〉MKK6 in the intestine were significantly upregulated in response to bacterial muramyl dipeptide (MDP) and L-Ala-γ-D-Glu-meso-diaminopimelic acid (Tri-DAP) stimulation. Moreover, subcellular localization analysis indicated that 〈em〉Ci〈/em〉MKK6 was distributed in both the cytoplasm and the nucleus of HEK293T cells. Finally, overexpression of 〈em〉Ci〈/em〉MKK6 significantly enhanced the transcriptional activity of the AP-1 reporter gene in HEK293T cells. Overall, these findings may help better clarify the immune function of teleost MKK6s and provide new insight into the immune defense mechanisms of grass carp.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Liting Wu, Shengli Fu, Xiaoxue Yin, Wenna Leng, Zheng Guo, Anli Wang, Jianmin Ye〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Affinity maturation of the antibody response, a process of antibody affinity increasing over response, is one of the key features of the mammalian immune system. However, the process is incompletely understood in teleost, including channel catfish (〈em〉Ictalurus punctaus〈/em〉). In this study, IgM affinity maturation in channel catfish was investigated by estimating the kinetics of antibody affinity using ELISA and ELISPOT assays. Fish were immunized with a T-cell dependent antigen (TNP-KLH), and individual serum IgM antibody titers and affinities, and IgM〈sup〉+〈/sup〉 antibody-secreting cells (ASCs) in peripheral blood were analyzed over a period of 14 weeks. A detectable serum anti-TNP response developed by 2-weeks post-immunization, and the maximal antibody production was observed by 6-weeks post-immunization. The average affinity of anti-TNP serum antibody increased consistently and reached the maximum by 10-weeks post-immunization. The increase of antibody affinity beyond the point of optimal antibody titer revealed that the affinity maturation of IgM antibody response occurred in channel catfish. Dissection of dynamics of individual affinity subpopulations indicated that a significant proportion of low affinity subpopulations appeared at early response, and high affinity subpopulations appeared predominantly at later, resulting in a 100-fold increase in affinity over response. Additional, TNP〈sup〉+〈/sup〉 IgM〈sup〉+〈/sup〉 ASCs was detected by 2-weeks post-immunization and achieved the maximal number by 6-weeks post-immunization. Using an inhibition ELISPOT assay, the findings of a consistent increase in the average affinity of secreted IgM antibody by peripheral blood ASCs, as the immune response progressed, confirmed the occurrence of the affinity maturation. Taken together, the results of this study indicated that affinity maturation occurred in channel catfish following immunization with a TD antigen TNP-KLH.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Weihua Gao, Shuai Li, Qiaoqing Xu, Dashi Zhu, Qin Zhang, Kai Luo, Wenbing Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The CXC chemokine receptors (CXCRs) play critical roles in innate and adaptive immune systems. In this study, six Asian swamp eel (〈em〉Monopterus albus〈/em〉) CXCRs (〈em〉Ma〈/em〉CXCR1–4) were identified and their molecular characterization and expression patterns were analyzed. The open reading frames (ORFs) of 〈em〉Ma〈/em〉CXCR1a, 〈em〉Ma〈/em〉CXCR1b, 〈em〉Ma〈/em〉CXCR2, 〈em〉Ma〈/em〉CXCR3a, 〈em〉Ma〈/em〉CXCR3b, and 〈em〉Ma〈/em〉CXCR4 were 1074 bp (base pairs), 1080 bp, 1125 bp, 1146 bp, 1083 bp, and 1140 bp, and encoded proteins of 357 aa (amino acids), 359 aa, 374 aa, 381 aa, 360 aa, and 379 aa, respectively. All these CXCRs have seven conserved transmembrane domains and four cysteines (with the exception of 〈em〉Ma〈/em〉CXCR3b). Multiple sequence alignment revealed that the 〈em〉Ma〈/em〉CXCRs possess a typical G-protein receptor family 1 signature and a DRY motif. There are also one to four potential N-glycosylation sites in the extracellular regions of the 〈em〉Ma〈/em〉CXCRs, mainly distributed in the N-terminus and extracellular hydrophilic loop (ECL) 2 region. Phylogenetic analysis demonstrated that the 〈em〉Ma〈/em〉CXCRs were clustered together with homologous proteins from other fish. Taken together with the amino acid identity and similarity analysis, these results suggested that the 〈em〉Ma〈/em〉CXCRs are conserved with other homologous genes, in which CXCR4 is more conserved than CXCR1–3. The 〈em〉Ma〈/em〉CXCRs loci showed conserved synteny among teleost fish, and we found that human CXCR1 shares a common ancestor with fish CXCR1a. 〈em〉Ma〈/em〉CXCRs were constitutively expressed in a wide range of tissues (especially in immune-related tissues) with different expression levels, suggesting that the 〈em〉Ma〈/em〉CXCRs have different roles in un-stimulated tissues, and may play vital roles under normal conditions. 〈em〉Ma〈/em〉CXCRs showed different fold changes in the spleen after 〈em〉Aeromonas veronii〈/em〉 and polyinosinic-polycytidylic acid (poly I:C) challenge, which suggested that 〈em〉Ma〈/em〉CXCR1a and 〈em〉Ma〈/em〉CXCR3a have longer antiviral activities compared with their antibacterial functions, and that 〈em〉Ma〈/em〉CXCR1b possesses stronger antiviral than antibacterial activity. 〈em〉Ma〈/em〉CXCR4 may play vital roles during bacterial and viral infection; however, 〈em〉Ma〈/em〉CXCR2 has relatively small effect in antibacterial and antiviral responses. The differential responses of these genes to bacteria and poly I:C implied the differences in the mechanisms of defense against viruses and bacteria.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Ye Yuan, Min Jin, Jia Xiong, Qicun Zhou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The experiment was conducted to evaluate the effects of different dietary dosage forms of copper supplementation on growth performance, hematological characteristics, antioxidant capacity, immune responses and gene expressions related to innate immune of juvenile Pacific white shrimp 〈em〉Litopenaeus vannamei〈/em〉. Three isonitrogenous and isolipidic diets were formulated to contain three dosage forms of copper: copper sulfate (Diet I-Cu), copper sulfate + copper amino acid complex (1: 1, Diet M-Cu) and copper amino acid complex from Availa〈sup〉®〈/sup〉Cu100 (Diet Availa-Cu), respectively. 360 Pacific white shrimp juveniles (initial weight 1.86 ± 0.03 g) were randomly allocated in 12 tanks corresponding to quadruplicate tanks of the three dietary treatments, and the 8-week feeding trail was conducted. The results indicated that percent weight gain (PWG) and specific growth rate (SGR) in shrimp fed M-Cu diet were significantly higher than that fed I-Cu diet. Survival, feed efficiency (FE), protein efficiency ratio (PER) of shrimp were not significantly different between all treatment groups. High contents of total protein (TP) and glucose (GLU) were found in shrimp fed the diet containing M-Cu, whereas contents of cholesterol (CHOL) and triacylglycerol (TAG) in shrimp fed M-Cu diet were significantly lower than that in I-Cu diet group. In hemolymph, shrimp fed M-Cu diet had high activities of phenoloxidase (PO), alkaline phosphatase (ALP) and acid phosphatase (ACP). While, Cu/Zn superoxide dismutase (Cu/Zn SOD), ceruloplasmin (CP) and lysozyme (LZM) in hemolymph were not significantly affected by different dietary dosage forms of copper. High activities of Cu/Zn SOD, ALP, ACP and LZM in hepatopancreas were observed in shrimp fed M-Cu diet. Shrimp fed diet supplemented with Availa-Cu showed a significantly higher gene expression levels of Cu/Zn 〈em〉sod〈/em〉, 〈em〉alp〈/em〉, 〈em〉acp〈/em〉 and 〈em〉lzm〈/em〉 in hepatopancreas than that fed I-Cu diet. This study indicated that copper amino acid complex was more effective than copper sulfate to improve growth performance and enhance antioxidant ability and innate immune system.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Ze-Quan Mo, Rui Han, Jiu-Le Wang, Lu-Yun Ni, Yu-Ling Su, Xue-Li Lai, Zhi-Chang He, Hong-Ping Chen, Yan-Wei Li, Hong-Yan Sun, Xiao-Chun Luo, Xue-Ming Dan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉MEK dual-specificity protein kinases are a group of mitogen-activated protein kinase kinases, which act as an integration point by transferring extracellular signals to the nucleus. To investigate the function of MEK in teleost fish, we cloned MEK1 and MEK2 cDNA sequences from the orange-spotted grouper (〈em〉Epinephelus coioides〈/em〉). EcMEK1 and EcMEK2 shared 80% amino acid identity with each other. EcMEK1 had 89–99% amino acid identity with teleosts or mammals, whereas EcMEK2 shared 85–97% amino acid identity. The exon structures of the grouper MEK1/2 genes were conserved with zebrafish and human MEK1/2. Tissue distribution analysis showed that 〈em〉EcMEK1〈/em〉 and 〈em〉EcMEK2〈/em〉 had a similar expression pattern in grouper tissues and was mainly transcribe in systemic immune organs. Both EcMEK1 and EcMEK2 were distributed throughout the cytoplasm of transfected GS or HEK293T cells. Overexpression of EcMEK1 or EcMEK2 activated Activator protein 1 dependent luciferase. The phosphorylation levels of EcMEK1/2 and EcERK1/2 were significantly increased in head kidney leukocytes by stimulation with PMA treatment. The grouper MEK1/2-ERK1/2 axis was activated in 〈em〉Cryptocaryon irritans〈/em〉 infection and showed an enhanced phosphorylation after immunization.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Sheng Zhou, Deli Song, Xiaofeng Zhou, Xinliang Mao, Xuefeng Zhou, Sunli Wang, Jingguang Wei, Youhua Huang, Wenxiong Wang, Su-Mei Xiao, Qiwei Qin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Probiotics are widely used for the improvement of animals' growth and health. However, few marine aquatic probiotics are applied and licensed in China. In this study, a 〈em〉Bacillus〈/em〉 spp. strain was isolated from the Hulong grouper gastrointestinal tract, which was identified as a new strain of 〈em〉Bacillus subtilis〈/em〉 and was named as 7k〈em〉. B. subtilis〈/em〉 7k showed desirable capability of sporulation and resistance to heat, simulated gastric juice and simulated duodenum juice, indicating its potential as probiotics. Seven antimicrobial chemicals were found in the secretion of the 〈em〉B. subtilis〈/em〉 7k. 〈em〉B. subtilis〈/em〉 7k addition in diet promoted the growth rate of Hulong groupers. Moreover, 〈em〉B. subtilis〈/em〉 7k can inhibit infection by iridovirus, making 〈em〉B. subtilis〈/em〉 7k a suitable kind of probiotic for maintaining fishes’ health. Our results also revealed that 〈em〉B. subtilis〈/em〉 7k induced non-specific immune response in Hulong grouper under virus infection. Hulong grouper fed by diets containing 〈em〉B. subtilis〈/em〉 7k at 10〈sup〉8〈/sup〉 and 10〈sup〉10〈/sup〉 cfu g〈sup〉−1〈/sup〉 for 4–8 weeks were significantly strengthened in serum lysozyme activity, serum alternative complement activity (ACH50), serum bactericidal activity, respiratory burst, superoxide dismutase activity (SOD), and phagocytic activity of head kidney leucocytes when compared with those fed by control diets. In conclusion, 〈em〉B. subtilis〈/em〉 7k was isolated and characterized to be a kind of process enduring, growth stimulating, immunity enhancing and health promoting probiotic using in grouper culture.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): D.C.M. Kulatunga, S.H.S. Dananjaya, Chamilani Nikapitiya, G.I. Godahewa, Jongki Cho, Cheol-Hee Kim, Jehee Lee, Mahanama De Zoysa〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Proteins with dithiol-disulfide oxidoreductase catalytic domain are well known for their capacity in the cellular redox homeostasis. In this study, we characterized the zebrafish thioredoxin domain containing 12 (Zf〈em〉txndc12〈/em〉) gene, analyzed the transcriptional responses and studied the functional properties of its recombinant protein. Full-length cDNA of Zf〈em〉txndc12〈/em〉 consists 519 bp coding region encoding 172 amino acids (AA) including the signal peptide. Highly consensus active motif (〈sup〉65〈/sup〉WCGAC〈sup〉69〈/sup〉) and probable ER retrieval motif (〈sup〉169〈/sup〉GDEL〈sup〉172〈/sup〉) were identified. Ubiquitous expression of Zf〈em〉txndc1〈/em〉2 mRNA was observed from one cell to juvenile stage as well as different organs of adult zebrafish. Moreover, whole mount 〈em〉in situ〈/em〉 hybridization (WISH) results showed a higher expression of Zf〈em〉txndc12〈/em〉 in primordial gills, central nerves system and eye. The tissue specific expression analysis (by qRT-PCR) also showed the highest expression in gills followed by brain in adult zebrafish. In larvae, up-regulated Zf〈em〉txndc1〈/em〉2 mRNA expression upon exposure to H〈sub〉2〈/sub〉O〈sub〉2,〈/sub〉〈em〉Edwardsiella tarda〈/em〉 and 〈em〉Saprolegnia parasitica〈/em〉 suggests that it may involve in both stress and immune responses. Moreover, transcriptional expression of Zf〈em〉txndc12〈/em〉 was up-regulated upon 〈em〉Streptococcus iniae〈/em〉 challenge in gills of adult zebrafish〈em〉.〈/em〉 The recombinant ZfTxndc12 (rZfTxndc12) was overexpressed, purified and tested for its biological activities. Results revealed that rZfTxndc12 is able to reduce the DNA damage and detoxify the H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 toxicity in concentration dependent manner. Overall results suggest that Zf〈em〉txndc12〈/em〉 is important antioxidant and immune functional member of the host defense system in zebrafish.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1050464818306855-fx1.jpg" width="469" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Yongliang Zhao, Qiang Lin, Ningqiu Li, V. Sarath Babu, Xiaozhe Fu, Lihui Liu, Hongru Liang, Xiaoling Liu, Li Lin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉MicroRNAs are non-coding RNAs, which widely participate in biological processes. In recent years, 〈em〉Siniperca chuatsi〈/em〉 rhabdovirus (SCRV) has caused mass mortality in Chinese perch (〈em〉Siniperca chuatsi〈/em〉). To identify specific miRNAs involved in SCRV infection, deep sequencing of microRNA on Chinese perch brain cell line (CPB) with or without SCRV infection were performed at 6 and 12 h post of infection (hpi). Totally 382 miRNAs were identified, including 217 known miRNA aligned with zebrafish miRNAs and 165 novel miRNAs by MiRDeep2 program. Of which 15 and 35 differentially-expressed miRNAs were determined respectively to 6 and 12 hpi. Nine miRNAs were selected randomly from the differentially-expressed miRNAs and validated by quantitative real-time PCR (qRT-PCR). These results were consistent with the microRNA sequencing results. Besides, target genes of 98 differentially-expressed miRNAs were predicted. Three of miRNAs (miR-122, miR-214, miR-135a) were selected, and its effects were analyzed in CPC cells transfected with appropriate miRNA mimics/inhibitors to evaluate its regulation effects by qRT-PCR and western blot. The results demonstrated that miR-214 inhibited the replication of SCRV, while miR-122 promoted the replication of SCRV and there was no correlation between the miR-135a and SCRV replication. These results will pave a new way for the development of effective strategies against the SCRV infection.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Yu-Chu Wang, Shao-Yang Hu, Chiu-Shia Chiu, Chun-Hung Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The probiotic efficiencies of the mixed probiotics containing 〈em〉Lactobacillus pentosus〈/em〉 BD6, 〈em〉Lac. fermentum〈/em〉 LW2, 〈em〉Bacillus subtilis〈/em〉 E20, and 〈em〉Saccharomyces cerevisiae〈/em〉 P13 for shrimp growth and health status improvement were better than those when using single probiotics. The probiotic mixture at a level of 10〈sup〉8〈/sup〉 colony-forming units (cfu) (kg diet)〈sup〉−1〈/sup〉 and the diets containing BD6 and E20 at 10〈sup〉9〈/sup〉 cfu (kg diet)〈sup〉−1〈/sup〉 significantly improved the growth and health status of shrimp, whereas the diets containing P13 or LW2 did not significantly affect the growth of shrimp. No significant difference in the carcass composition was recorded among the control and treatments. After 56 days of feeding, shrimp fed the diet containing the probiotic mixture (10〈sup〉7〈/sup〉∼10〈sup〉9〈/sup〉 cfu (kg diet)〈sup〉−1〈/sup〉) had higher survival after injection with the 〈em〉V. alginolyticus〈/em〉, but 10〈sup〉9〈/sup〉 cfu (kg diet)〈sup〉−1〈/sup〉 of single probiotics (except for 〈em〉S. cerevisiae〈/em〉 P13) had to be administered to improve shrimp survival. The better disease resistance of shrimp in groups fed the probiotic mixture might have been due to increased phenoloxidase activity, respiratory bursts, and lysozyme activity of hemocytes. Therefore, we considered that the probiotic mixture could adequately provide probiotic efficiency for white shrimp, and a diet containing 10〈sup〉8〈/sup〉 cfu (kg diet)〈sup〉−1〈/sup〉 probiotic mixture is recommended.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Alba R. Ochoa-Meza, Ana R. Álvarez-Sánchez, Carlos R. Romo-Quiñonez, Aarón Barraza, Francisco J. Magallón-Barajas, Alexis Chávez-Sánchez, Juan Carlos García-Ramos, Yanis Toledano-Magaña, Nina Bogdanchikova, Alexey Pestryakov, Claudio Humberto Mejía-Ruiz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The global aquaculture has shown an impressive growth in the last decades contributing with a major part of total food fish supply. However, it also helps in the spread of diseases that in turn, causes great economic losses. The White Spot Syndrome Virus (WSSV) is one of the major viral pathogen for the shrimp aquaculture industry. Several attempts to eliminate the virus in the shrimp have been addressed without achieving a long-term effectiveness. In this work, we determine the capacity of the commercial non-toxic PVP-coated silver nanoparticles to promote the response of the immune system of WSSV-infected shrimps with or without an excess of iron ions. Our results showed that a single dose of metallic silver in the nanomolar range (111 nmol/shrimp), which is equivalent to 12 ng/mL of silver nanoparticles, produces 20% survival of treated infected shrimps. The same concentration administered in healthy shrimps do not show histological evidence of damage. The observed survival rate could be associated with the increase of almost 2-fold of LGBP expression levels compared with non-treated infected shrimps. LGBP is a key gene of shrimp immunological response and its up-regulation is most probably induced by the recognition of silver nanoparticles coating by specific pathogen-associated molecular pattern recognition proteins (PAMPs) of shrimp. Increased LGBP expression levels was observed even with a 10-fold lower dose of silver nanoparticles (1.2 ng/shrimp, 0.011 nmol of metallic silver/shrimp). The increase in LGBP expression levels was also observed even in the presence of iron ion excess, a condition that favors virus proliferation. Those results showed that a single dose of a slight amount of silver nanoparticles were capable to enhance the response of shrimp immune system without toxic effects in healthy shrimps. This response could be enhanced by administration of other doses and might represent an important alternative for the treatment of a disease that has still no cure, white spot syndrome virus.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Kwang-Min Choi, Min-Soo Joo, Dong Hee Cho, Jin-Sol Bae, Ji-Min Jung, Jee Youn Hwang, Mun-Gyeong Kwon, Jung Soo Seo, Seong Don Hwang, Bo-Yeong Jee, Do-Hyung Kim, Chan-Il Park〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Peptidoglycan recognition protein 2 (PGRP2) is a Zn〈sup〉2+〈/sup〉-dependent peptidase that plays important roles in binding to microbial components of the cell membrane, inducing phagocytosis and antimicrobial activity. Rock bream (〈em〉Oplegnathus fasciatus〈/em〉) PGRP2 (RbPGRP2) was identified in the intestine by next generation sequencing (NGS) analysis. The open reading frame (ORF) the RbPGRP2 cDNA (470 amino acid residues) contains a peptidoglycan recognition protein domain (residues 300 to 446). Alignment analysis revealed that RbPGRP2 shares 37.6–53.5% overall sequence identity with the PGRP2s of other species. Phylogenetic analysis revealed that RbPGRP2 clustered together with PGRP2s from teleosts. In healthy rock bream, RbPGRP2 was found to be ubiquitously expressed in all of the examined tissues, especially in the liver. RbPGRP2 expression was significantly upregulated in all of the examined tissues of rock bream after infection with 〈em〉Edwardsiella piscicida〈/em〉, 〈em〉Streptococcus iniae〈/em〉 and red sea bream iridovirus (RSIV) compared with the control. Purified rRbPGRP2 interactions with bacteria and inhibited the growth of bacteria in the presence of Zn〈sup〉2+〈/sup〉. These results indicate that RbPGRP2 plays an important role in the innate immune response against bacterial infection.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Chih-Chung Wu, Chia-Ling Lin, Chun-Yung Huang, Shuchen Hsieh, Chun-Hung Liu, Shu-Ling Hsieh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Innate immunity and resistance against 〈em〉Vibrio alginolyticus〈/em〉 in white shrimp, 〈em〉Litopenaeus vannamei〈/em〉, that received α-phellandrene were examined. The results indicated that the percent survival of shrimp receiving 4, 8, and 12 μg g〈sup〉−1〈/sup〉 α-phellandrene was significantly higher than that of control shrimp after 72 h (p 〈 0.05). In a separate experiment, the phenoloxidase (PO), respiratory bursts, superoxide dismutase (SOD), and phagocytic and lysozyme activity of 〈em〉L. vannamei〈/em〉 receiving 8 and 12 μg g〈sup〉−1〈/sup〉 α-phellandrene were significantly higher than those of the other groups upon challenge with 〈em〉V. alginolyticus〈/em〉 at 24–60, 36–60, 12–60, 12–72 and 48–72 h, respectively. However, no significant differences in the total haemocyte counts (THC) of 〈em〉L. vannamei〈/em〉 receiving any dose of α-phellandrene and of control shrimp were observed at 12–72 h. The expression (mRNA transcripts) of the immune genes prophenoloxidase (proPO), LPS- and β-1,3-glucan-binding protein (LGBP) and peroxinectin (PE) of shrimp receiving α-phellandrene at 8 and 12 μg g〈sup〉−1〈/sup〉 significantly increased after challenge with 〈em〉V. alginolyticus〈/em〉 for 72 h (p 〈 0.05). We conclude that the immune ability and resistance against 〈em〉V. alginolyticus〈/em〉 infection increased in 〈em〉L. vannamei〈/em〉 receiving 〉4 μg g〈sup〉−1〈/sup〉 α-phellandrene. These results indicated that α-phellandrene plays an important role in the innate immunity of white shrimp.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Min Wang, Xueyang Zhang, Shicui Zhang, Zhenhui Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉GPR84 was identified as a receptor for medium-chain fatty acids with carbon chain lengths of 9–14. It has previously been reported that lipopolysaccharide (LPS) induces significantly up-regulation of zebrafish 〈em〉gpr84〈/em〉, and zebrafish 〈em〉gpr84〈/em〉 overexpression markedly increased the LPS-stimulated production of the cytokine 〈em〉IL-12〈/em〉. Here we expanded on these studies to further investigate the roles of zebrafish Gpr84 in immune reaction. Flow cytometric assay was used to assess the effects of zebrafish Gpr84 on the phagocytosis of bacteria by macrophages. It was found that overexpression of zebrafish 〈em〉gpr84〈/em〉 significantly increased both the phagocytic ability (PA) and phagocytic index (PI) values of the macrophages engulfing the bacteria, suggesting that zebrafish Gpr84 was able to promote the phagocytosis of bacteria by the macrophages. The data proves the direct effect of Gpr84 in immune reaction.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Zhi-long Chen, Bei-Ni Gong, Qi-long Wang, Zhi-hui Xiao, Chong Deng, Wen-qian Wang, Yingqiu Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A primitive adaptive immune system has recently been suggested to be present in a basal chordate amphioxus (〈em〉Branchiostoma belcheri,〈/em〉 Bb), making it an ideal model for studying the origin of adaptive immune. The novel protein kinase C isoform PKC-θ, but not its closest isoform PKC-δ, plays a critical role for mammalian T-cell activation via translocation to immunological synapse (IS) mediated by a unique PKC-θ V3 domain containing one PxxP motif. To understand the evolution of this unique PKC-θ V3 domain and the primitive adaptive immune system in amphioxus, we comparatively studied the orthologs of PKC-δ and -θ from amphioxus and other species. Phylogenetic analysis showed BbPKC-δ/θ to be the common ancestor of vertebrate PKC-δ and PKC-θ, with a V3 domain containing two PxxP motifs. One motif is conserved in both zebrafish and mammalian PKC-θ but is absent in PKC-δ V3 domain of these species, and has already emerged in drosophila PKC-δ. The other non-conserved motif emerged in BbPKC-δ/θ, and only retained in 〈em〉Danio rerio〈/em〉 PKC-δ (DrPKC-δ) but lost in mammalian PKC-δ and -θ. Comparative analyses of the sequence and function of BbPKC-δ/θ, DrPKC-δ, DrPKC-θ and 〈em〉Homo sapiens〈/em〉 PKC-θ (HsPKC-θ) in IS translocation and T-cell receptor (TCR)-induced NF-κB activation revealed that retention of the conserved PxxP motif and loss of the non-conserved PxxP motif in mammalian PKC-θ and loss of both PxxP motifs in mammalian PKC-δ accomplish the unique function of PKC-θ in T cells. Together, this study suggests an evolutionary mechanism for PKC-θ unique V3 and reveals BbPKC-δ/θ is the common ancestor of PKC-δ and -θ with a functional proto-V3 domain, supplying new evidence for the existence of primitive adaptive immune system in amphioxus.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Matthieu Paiola, Catarina Moreira, Aurélie Duflot, Thomas Knigge, Tiphaine Monsinjon〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Besides their obvious role in sex determination and reproduction, oestrogens display a prominent and complex immunomodulatory role across all vertebrates. To date, our knowledge on the oestrogenic immunomodulation in non-mammalian species is, however, scarce. In both teleosts and mammals, the direct immunomodulatory function of oestrogen is underscored by the presence of multiple oestrogen receptor subtypes in the various immune cells. For a better understanding of the regulatory processes, we investigated the oestrogen receptor expression in two major lymphoid organs of European sea bass: the head-kidney and the spleen. All oestrogen receptor subtypes, including nuclear and membrane oestrogen receptors, were present in both immune organs as well as in the isolated leucocytes. The same findings have been previously made for the thymus. To determine the oestrogen responsiveness of the different immune cell populations and to evaluate the importance of non-genomic and genomic pathways, we assessed the kinetics and the concentration dependent effects of 17β-oestradiol on isolated leucocytes from the head-kidney, the spleen and the thymus 〈em〉in vitro〈/em〉. Given the importance of reactive oxygen species as signalling and defence components in mammalian immune cells, the oxidative burst capacity, the redox status and the viability of both lymphoid and myeloid cells were measured by flow cytometry. The treatment with 17β-oestradiol specifically modulated these parameters depending on (1) the time kinetic, (2) the concentration of 17β-oestradiol, (3) the immune cell population (lymphoid and myeloid cells) as well as (4) the lymphoid organs from which they originated. The observed 〈em〉in vitro〈/em〉 oestrogenic effects as well the presence of various oestrogen receptor subtypes in the immune cells of sea bass suggest a complex and direct oestrogenic action 〈em〉via〈/em〉 multiple interconnected oestrogen-signalling pathways. Additionally, our study suggests that the oestrogenic regulation of the sea bass immune function involves a direct and tissue specific modulation of the immune cell redox biology comprising redox signalling, NADPH-oxidase activity and H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉-permeability, thus changing oxidative burst capacity and immature T cell fate because oestrogen impacted thymocyte viability. Importantly, immune cells from both primary and secondary lymphoid organs have shown specific 〈em〉in vitro〈/em〉 oestrogen-responsiveness. As established in mammals, oestrogen is likely to be specifically and directly involved in immature T cell differentiation and mature immunocompetent cell function in sea bass too.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology〈/p〉 〈p〉Author(s): Fei Ke, Qi-Ya Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Viruses are important and lethal pathogens that hamper aquatic animals. The result of the battle between host and virus would determine the occurrence of diseases. The host will fight against virus infection with various responses such as innate immunity, adaptive immunity, apoptosis, and so on. On the other hand, the virus also develops numerous strategies such as immune evasion to antagonize host antiviral responses. Here, We review the research advances on virus mediated immune evasions to host responses containing interferon response, NF-κB signaling, apoptosis, and adaptive response, which are executed by viral genes, proteins, and miRNAs from different aquatic animal viruses including 〈em〉Alloherpesviridae〈/em〉, 〈em〉Iridoviridae〈/em〉, 〈em〉Nimaviridae〈/em〉, 〈em〉Birnaviridae〈/em〉, 〈em〉Reoviridae〈/em〉, and 〈em〉Rhabdoviridae〈/em〉. Thus, it will facilitate the understanding of aquatic animal virus mediated immune evasion and potentially benefit the development of novel antiviral applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Yanyan Chen, Shuanghu Cai, Jichang Jian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉〈em〉Vibrio alginolyticus〈/em〉 is well-known as an opportunistic Gram-negative pathogen, which endangers the development of global aquaculture as well as human health. In this study, a Δ〈em〉acfA〈/em〉 mutant strain and complementation of the Δ〈em〉acfA〈/em〉 mutant (C-〈em〉acfA〈/em〉) were constructed. The Δ〈em〉acfA〈/em〉 mutant was tested in pearl gentian grouper (♀〈em〉Epinephelus fuscoguttatus〈/em〉 × ♂〈em〉Epinephelus lanceolatu〈/em〉) to observe the changes in virulence and evaluate its potential as an attenuated live vaccine. The results showed that the Δ〈em〉acfA〈/em〉 mutant caused a high antibody titer and a significant reduction in the ability to colonize the intestine of pearl gentian grouper. Grouper vaccinated with Δ〈em〉acfA〈/em〉 mutant were more tolerant of the infection by virulent 〈em〉V. alginolyticus〈/em〉 HY9901 without inducing clinical symptoms and obvious pathological changes. The relative percent survival value of pearl gentian grouper vaccinated with 〈em〉ΔacfA〈/em〉 mutant intraperitoneal injection reached 81.1% after challenging with 〈em〉V. alginolyticus〈/em〉 HY9901. The specific antibody titers immunized with Δ〈em〉acfA〈/em〉 was significantly higher than that in the PBS group. The antibody titer of Δ〈em〉acfA〈/em〉 group displayed the tendency of rising up from the first to fourth week and declining from fifth to eighth week and reached the peak at the fourth week. In the meanwhile, the expression level of genes associated with immunity, including IL-1β, TNF-α, IL-16, IgM, CD8α and MHC-Iα, was up-regulated after vaccination, indicating that the Δ〈em〉acfA〈/em〉 can induce effective and durable immune response in pearl gentian grouper and it may be an effective attenuated live vaccine candidate for the prevention of infections by 〈em〉V. alginolyticus〈/em〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Xinyan Wang, Yafei Guo, Chao Wen, Mengyuan Lv, Ning Gan, Hong Zhou, Anying Zhang, Kun Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Interleukin (IL)-6 receptor (IL-6R) can specifically bind to IL-6 and the complex subsequently recruits a transmembrane signal transducer, gp130, to trigger the intracellular signal transduction. IL-6R exists in two forms, a transmembrane IL-6R and a soluble IL-6R (sIL-6R), leading to different signal transduction mechanisms as classic signaling and trans-signaling, respectively. There is now a general consensus that these two modes of signal transduction can mediate anti-inflammatory and pro-inflammatory activities of IL-6. The study on Il-6r is limited although Il-6 has been well studied in teleost. In the present study, a cDNA encoding grass carp Il-6r (gcIl-6r) was isolated. An 〈em〉in〈/em〉-〈em〉silico〈/em〉 analysis showed that gcIl-6r shared the same functional domains and conserved gene synteny at its loci with mouse homologue, and its amino acid sequence was conserved in fish species. A tissue distribution assay demonstrated that gc〈em〉il6r〈/em〉 mRNA was expressed with high levels in immune tissues including spleen and head kidney, and its expression was induced by LPS and Poly I:C in grass carp head kidney leucocytes (HKLs). An 〈em〉in vitro〈/em〉 binding assay showed that recombinant soluble gcIl-6r (rgcsIl-6r) could specifically bind to recombinant gcIl-6 (rgcIl-6) protein. Moreover, rgcIl-6 stimulated 〈em〉suppressor of cytokine signaling 3〈/em〉 (〈em〉socs3〈/em〉)'s mRNA expression in grass carp HKLs and it combined with rgcsIl-6r increased 〈em〉socs3〈/em〉 mRNA expression in CIK cells with gp130 but without Il-6r expression. In HKLs, rgcIl-6 stimulated the mRNA levels of both pro-inflammatory (〈em〉tnfa〈/em〉 and 〈em〉il1b〈/em〉) and anti-inflammatory (〈em〉il10〈/em〉) cytokines, and rgcsIl-6r could augment these stimulatory effects of gcIl-6. Taken these data together, gcsIl-6r can mediate the immuno-regulatory functions of gcIl-6 and has an agonistic property in these actions of Il-6 in grass carp.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Fanxing Meng, Yuanyuan Zhang, Jianbo Zhou, Ming Li, Ge Shi, Rixin Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Unlike the normal anadromous lifestyle, Chinese native Dolly Varden char (〈em〉Salvelinus malma〈/em〉) is locked in land and lives in fresh water lifetime. To explore the effect of freshwater adaption on its immune system, we constructed a pooled cDNA library of hepatopancreas and spleen of Chinese freshwater Dolly Varden char (〈em〉S. malma〈/em〉). A total of 27,829 unigenes were generated from 31,233 high-quality transcripts and 17,670 complete open reading frames (ORF) were identified. Totally 25,809 unigenes were successfully annotated and it classified more native than adaptive immunity-associated genes, and more genes involved in toll-like receptor signal pathway than those in complement and coagulation cascades (51 vs 3), implying the relative more important role of toll-like receptors than the complement system under bacterial injection for the freshwater Dolly Varden char. These huge different numbers of TLR and complement system identified in freshwater Dolly Varden char probably caused by distinct evolution pressure patterns between fish TLR and complement system, representative by 〈em〉TLR3〈/em〉 and 〈em〉TLR5〈/em〉 as well as 〈em〉C4〈/em〉 and 〈em〉C6〈/em〉, respectively, which were under purifying and positively selecting pressure, respectively. Further seawater adaptation experiment and the comparison study with our library will no doubt be helpful to elucidate the effect of freshwater adaption of Chinese native Dolly Varden char on its immune system.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Haiyang Yu, Xin Xu, Quanqi Zhang, Xubo Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Cystatins are natural tight-binding reversible inhibitors of cysteine proteases found in a wide arrange of organisms. Studies have shown that cystatins play important roles under both physiological and pathological conditions in mammals. However, much less is known about fish cystatins. In this study, we described the identification and analysis of the gene encoding cystatin C in Japanese flounder (〈em〉Paralichthys olivaceus〈/em〉). This gene had a high homology with the sequence of cystatin C in many fish species and had a signal peptide and three conserved functional sites. The results of qRT-PCR showed that the gene was highly expressed in the liver. Lipopolysaccharide, peptidoglycan and polyinosinic-polycytidylic acid all increased its expression after stimulation. Functional analysis showed that the recombinant 〈em〉P. olivaceus〈/em〉 cystatin C purified from 〈em〉Escherichia coli〈/em〉 had cysteine protease inhibitory activity and could inhibit bacterial growth by binding to bacteria. Meanwhile, rPocystatin C could up-regulate the expression of cytokines tumor necrosis factor α and interleukin 10. These results indicated that cystatin C of 〈em〉P. olivaceus〈/em〉 might be considered to have the similar immunomodulatory function to mammalian cystatin.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Ronghui Li, Suhua Bai, Decui Yang, Chaohua Dong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Temperature is an important environmental factor influencing crustacean resistance to pathogen infection. However, the mechanism underlying immune regulation by temperature remains unclear in crustacean. Here, we report a 〈em〉Ras〈/em〉 gene of crayfish (designated as 〈em〉PcRAS1〈/em〉) which is involved in immune regulation of crayfish under high temperature. 〈em〉PcRAS1〈/em〉 is induced by both high temperature and bacterial infection and the induction by bacterial infection is associated with temperature. Significant changes of 〈em〉PcRAS1〈/em〉 expression was observed at 32 °C and 24 °C after infection with 〈em〉Aeromonas hydrophila〈/em〉, but relative moderate alternation was found at 16 °C after challenged with 〈em〉A. hydrophila. PcRAS1〈/em〉 silencing significantly reduced crayfish survival from high temperature (32 °C and 24 °C) or bacterial infection at 32 °C, but there was no significant effect on survival from bacterial infection at 24 °C or 16 °C. Further analysis reveals that PO activity is reduced by high temperature or enhanced by bacterial infection. Moreover, both the decreased PO activity and the enhanced PO activity are affected by 〈em〉PcRAS1〈/em〉 expression. 〈em〉PcRAS1〈/em〉 silencing further reduces PO activity under high temperature and compromises the enhanced PO activity by bacterial infection. Lipid peroxidation (LPO) and total antioxidant capacity (TAC) are also involved in the responses to high temperature. LPO is enhanced by lower temperature. TAC is reduced by high temperature and TAC change resulting from high temperature is amplified by 〈em〉PcRAS1〈/em〉 silencing. These results collectively indicate that 〈em〉PcRAS1〈/em〉 is involved in immune regulation against bacterial infection mediated by temperature.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Pei-Hua Zheng, Lei Wang, An-Li Wang, Xiu-Xia Zhang, Jian-Min Ye, Dong-Mei Wang, Jing-Feng Sun, Jun-Tao Li, Yao-Peng Lu, Jian-An Xian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Glutaredoxin (Grx) is a class molecule oxidoreductase, which can regulate the redox state of proteins and plays a key role in antioxidant defense. However, the informations of Grx cDNA sequences and their functions are lack in decapod crustacea. In the present study, the cDNA of LvGrx 2 was cloned from the Pacific white shrimp, 〈em〉Litopenaeus vannamei〈/em〉. The open reading frame (ORF) of LvGrx 2 was 360 bp, which encoded a polypeptide of 119 amino acids. The molecular mass of the predicted protein is 12.87 kDa with an estimated pI of 8.22. Sequence alignment showed that the amino acid sequence of LvGrx 2 shares 59%, 59% and 58% identity with that of the coelacanth 〈em〉Latimeria chalumnae,〈/em〉 the plateau frog 〈em〉Nanorana parkeri〈/em〉 and the half-smooth tongue sole 〈em〉Cynoglossus semilaevis〈/em〉, respectively. Quantitative real-time PCR analysis revealed that LvGrx 2 were detected in a wide range of tissues, with highest expression in gill, hepatopancrea and intestine, and weakest expression in muscle. The expression responses of LvGrx 2 were analyzed in hepatopancrea and gill after ammonia-N stress or lipopolysaccharide (LPS) injection. During ammonia-N exposure, the LvGrx 2 transcriptions in hepatopancrea and gill significantly up-regulated, and the peak value appeared after 12 h and 24 h exposure respectively. After LPS injection, expression levels of LvGrx 2 in hepatopancrea obviously increased in the early and late stages, while LvGrx 2 transcription in gill sharply up-regulated in the middle period. These results suggest that LvGrx 2 may play a vital role in shrimp defense system against environmental stress and pathogen infection. RNA interference experiment was designed to further probe roles of LvGrx 2 during ammonia-N exposure. Ammonia-N induced obvious improvement in expression levels of LvGrx 2, LvGrx 3, GPx, GST and Trx, accompanied by increases of protein carbonyl and malondialdehyde (MDA) contents. However, transcription of GPx and GST were much weaker in LvGrx 2 interfered-shrimp, and oxidative damage in both lipid and protein were more serious. These results further suggest that LvGrx 2 in shrimp participates in oxidative defence and regulation of antioxidant system.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Ying Huang, Jianlin Pan, Xuguang Li, Qian Ren, Zhe Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Peptidoglycan (PGN) is an important target of recognition in invertebrate innate immunity. PGN recognition proteins (PGRPs) are responsible for PGN recognition. In this study, we cloned and functionally analyzed a short PGRP (〈em〉HcPGRP2〈/em〉) from the triangle-shell pearl mussel 〈em〉Hyriopsis cumingii〈/em〉. The full-length cDNA sequence of 〈em〉HcPGRP2〈/em〉 gene was 1185 bp containing an open reading frame of 882 bp encoding a 293 amino acid protein. HcPGRP2 was predicted to have two SH3b domains and a conserved C-terminal PGRP domain. Quantitative real-time RT-PCR showed that 〈em〉HcPGRP2〈/em〉 was expressed in all examined tissues and its expression was induced most significantly by 〈em〉Staphylococcus aureus〈/em〉 and 〈em〉Vibrio parahaemolyticus〈/em〉 in the hepatopancreas and gills. RNA interference by siRNA results revealed that 〈em〉HcPGRP2〈/em〉 was involved in the regulation of whey acidic protein, theromacin, and defensin expression. As a pattern-recognition receptor, recombinant HcPGRP2 (rHcPGRP2) protein can bind and agglutinate (Ca〈sup〉2+〈/sup〉 dependent) all tested bacteria. rHcPGRP2 exhibited specific binding to PGN but not to lipopolysaccharide. Moreover, rHcPGRP2 inhibited the growth activities of 〈em〉S. aureus〈/em〉 and 〈em〉V. parahaemolyticus in vitro〈/em〉 and accelerated the clearance of 〈em〉V. parahaemolyticus in vivo〈/em〉. Overall, our results indicated that HcPGRP2 may play an important role in the antibacterial immune mechanisms of 〈em〉H. cumingii〈/em〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Sirikorn Kitiyodom, Somrudee Kaewmalun, Naiyaphat Nittayasut, Kunat Suktham, Suvimol Surassmo, Katawut Namdee, Channarong Rodkhum, Nopadon Pirarat, Teerapong Yata〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Vaccination is the most effective approach for prevention of infectious diseases in aquaculture. Although immersion vaccination is more applicable compared to in-feed/oral administration and injection, this method suffers from low potency as the efficiency of uptake of antigens through mucosal membranes is limited. In this study, we have successfully developed a mucoadhesive vaccine delivery system to enhance the efficacy of direct immersion vaccination against 〈em〉Flavobacterium columnare〈/em〉, the causative agent of columnaris disease in red tilapia. A formalin-killed negatively charged, bacterial cell suspension was used to prepare a mucoadhesive vaccine by electrostatic coating with positively charged chitosan. Our results demonstrate that the chitosan-complexed vaccine greatly increases its mucoadhesiveness, thus increasing the chances of vaccine uptake by the gill mucosa and improving the protection obtained against columnaris infection. The surface charge of the chitosan-complexed vaccine was altered from anionic to cationic after chitosan modification. Tilapia were vaccinated with the prepared chitosan-complexed vaccine by immersion. The challenge test was then carried out 30 and 60 days post vaccination, which resulted in a high level of mortalities in the non-vaccinated and uncomplexed vaccine groups. A high relative percentage survival (RPS) of vaccinated fish was noted with the mucoadhesive vaccine. Our results indicated that the naked vaccine failed to protect the fish from columnaris infection, which is consistent with the mucoadhesive assays performed during the study showing that the naked vaccine was unable to bind to mucosal surfaces. This system is therefore an effective method for immersion vaccination in order to deliver the antigen preparation to the mucosal surface membrane of the fish.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1050464818308040-fx1.jpg" width="446" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Xiumei Wei, Tianyu Zhao, Kete Ai, Yu Zhang, Huiying Li, Jialong Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉RAF proto-oncogene serine/threonine-protein kinase (c-Raf) is a MAP kinase kinase kinase (MAPKKK) that participates in the Erk1/2 pathway and plays an important role in lymphocyte activation. However, the study on how c-Raf regulates adaptive immunity in non-mammal is still limited. In present study, based on analysis of sequence characteristics of c-Raf from 〈em〉Oreochromis niloticus〈/em〉 (On-c-Raf), we investigated its regulation roles on teleost lymphocyte activation. The On-c-Raf was highly conserved during evolution, which was composed of a Raf-like Ras-binding domain (RBD), a protein kinase C conserved region 1 (C1) domain and a serine/threonine protein kinase catalytic (S_TKc) domain. Its mRNA showed a wide distribution in tissues of 〈em〉O. niloticus〈/em〉 and with the highest expression in gill. After 〈em〉Aeromonas hydrophila〈/em〉 infection, during the adaptive immune stage transcription level of On-c-Raf was significantly upregulated on day 8, but came back to original level on day 16 and 30, suggesting the potential involvement of On-c-Raf in primary response but not memory formation. Furthermore, On-c-Raf mRNA in leukocytes of Nile tilapias was obviously induced by in vitro stimulation of T cell mitogen PHA. More importantly, in vitro stimulation of lymphocytes agonist PMA augmented phosphorylation level of On-c-Raf in leukocytes detected by western-blot and immunofluorescent. Thus, c-Raf regulated lymphocyte activation of Nile tilapia on both mRNA and phosphorylation level. Together, our results revealed that the c-Raf from teleost Nile tilapia engaged in adaptive immune response by regulating lymphocytes activation. Since the regulatory mechanism of lymphocyte-mediated adaptive immunity is largely unknown in teleost, our study provided important evidences to understand teleost adaptive immunity, and also shed a novel perspective for the evolution of adaptive immune system.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Ali Reza Khansari, Joan Carles Balasch, Eva Vallejos-Vidal, Mariana Teles, Camino Fierro-Castro, Lluis Tort, Felipe E. Reyes-López〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The stress and immune-related effects of short-term (1, 6 and 24 h) air exposure stress (1 min), bath vaccination with 〈em〉Vibrio anguillarum〈/em〉 bacterin, and both stressors combined were evaluated in liver and spleen of 〈em〉Sparus aurata〈/em〉, 〈em〉Danio rerio〈/em〉 and 〈em〉Onchorhynchus mykiss〈/em〉. Expression profiles of immune (〈em〉interleukin 1 beta〈/em〉: 〈em〉il1β〈/em〉; 〈em〉tumor necrosis factor alpha〈/em〉: 〈em〉tnfα〈/em〉; 〈em〉interleukin 10〈/em〉: 〈em〉il10〈/em〉; 〈em〉tumor growth factor beta〈/em〉: 〈em〉tgfβ1〈/em〉; 〈em〉immunoglobulin M〈/em〉: 〈em〉igm〈/em〉; lysozyme: 〈em〉lys〈/em〉; 〈em〉complement protein c3〈/em〉: 〈em〉c3〈/em〉) and stress-related genes (〈em〉glucocorticoid receptor〈/em〉: 〈em〉gr〈/em〉; 〈em〉heat shock protein 70〈/em〉: hsp70; and 〈em〉enolase〈/em〉) were analysed by RT-qPCR. Cortisol level was assessed by radioimmunoassay. The gene expression patterns in liver and spleen were found to be differentially regulated in a time- and organ-dependent manner among species. In seabream, a higher 〈em〉il1β〈/em〉-driven inflammatory response was recorded. In zebrafish, air exposure stress but not bath vaccination alone modulated most of the changes in liver and spleen immune transcripts. Stressed and vaccinated trout showed an intermediate pattern of gene expression, with a lower upregulation of immune-related genes in liver and the absence of changes in the expression of hsp70 and enolase in spleen (as it was observed in seabream but not in zebrafish). Following air exposure, cortisol levels increased in plasma 1 h post-stress (hps) and then decreased at 6 hps in 〈em〉O. mykiss〈/em〉 and 〈em〉D. rerio〈/em〉. By contrast, in 〈em〉S.aurata〈/em〉 the cortisol level remained higher at 6 hps suggesting a greater degree of responsiveness to this stressor. When fish were exposed to combined air exposure plus bath vaccination cortisol levels were also augmented at 1 and 6 hps in 〈em〉O. mykiss〈/em〉 and 〈em〉S.aurata〈/em〉 and restored to basal level at 24 hps, whereas in 〈em〉D. rerio〈/em〉 the response was higher in response to the combination of both stressors. In addition, 〈em〉V. anguillarum〈/em〉 bacterin vaccination triggered cortisol secretion only in 〈em〉D. rerio,〈/em〉 suggesting a greater responsiveness of 〈em〉D. rerio〈/em〉 hypothalamic-pituitary-interrenal axis. Overall, comparing the tissue transcription responsiveness, liver was found to be more implicated in the response to handling stress compared to spleen. These results also indicate that a species-specific response accounts for the deviations of stress and immune onset in the liver and spleen in these fish species.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Irene Cano, Nick GH. Taylor, Amanda Bayley, Susie Gunning, Robin McCullough, Kelly Bateman, Barbara F. Nowak, Richard K. Paley〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An 〈em〉in vitro〈/em〉 model to study the host response to 〈em〉Neoparamoeba perurans〈/em〉, the causative agent of amoebic gill disease (AGD), was evaluated. The rainbow trout gill derived cell line, RTgill-W1, was seeded onto permeable cell culture supports and maintained asymmetrically with apical seawater. Cells were inoculated with either a passage attenuated or a recent wild clone of 〈em〉N. perurans〈/em〉. Amoebae, loaded with phagocytosed fluorescent beads, were observed associated with host cells within 20 min post inoculation (pi). By 6 h small foci of cytopathic effect appeared and at 72 h cytolysis was observed, with total disruption of the cell monolayer at 96 h pi. Due to cell monolayer disruption, the platform could not support proliferation of amoebae, which showed a 3-log reduction in parasite 18S rRNA mRNA after 72 h (10〈sup〉6〈/sup〉 copies at 1 h to 10〈sup〉3〈/sup〉 at 72 h pi). SEM observations showed amoebae-like cells with either short pseudopodia and a malleiform shape, or, long pseudopodia embedded within the gill cells and erosion of the cell monolayer. To study the host immune response, inoculated gill cells were harvested from triplicate inserts at 0, 1, 3, 6, 24 and 48 h pi, and expression of 12 genes involved in the Atlantic salmon response to AGD was compared between infected and uninfected cells and between amoebic clones. Both clones induced similar host inmate immune responses, with the up-regulation of proinflammatory cytokine IL1β, complement C3 and cell receptor MHC-1. The Th2 pathway was up-regulated, with increased gene expression of the transcription factor GATA3, and Th2 cytokines IL10, IL6 and IL4/13A. PCNA and AG-2 were also up-regulated. The wild clone induced significantly higher up-regulation of IL1β, MHC-1, PCNA, lysozyme and IL10 than the attenuated clone for at least some exposure times, but AG-2 gene expression was higher in cells inoculated with the attenuated one. A principal component analysis showed that AG-2 and IL10 were key genes in the 〈em〉in vitro〈/em〉 host response to 〈em〉N. perurans〈/em〉. This 〈em〉in vitro〈/em〉 model has proved to be a promising tool to study host responses to amoebae and may therefore reduce the requirement for in 〈em〉vivo〈/em〉 studies when evaluating alternative therapeutants to AGD control.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Mu-Yang Li, Li Sun, Xiao-Tian Niu, Xiu-Mei Chen, Jia-Xin Tian, Yi-Di Kong, Gui-Qin Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present study was conducted to evaluate the protective effects of astaxanthin against lipopolysaccharide (LPS)-induced inflammatory responses in 〈em〉Channa argus〈/em〉 in vivo and ex vivo. Primary hepatocytes were exposed to different concentrations of LPS for 24 h to induce an inflammatory response, and the protective effects of astaxanthin against LPS-induced inflammation were studied ex vivo and in vivo. Hepatocytes exposed to LPS (5–20 μg mL〈sup〉−1〈/sup〉) alone for 24 h resulted in a significant increase in lactate dehydrogenase release (LDH), Nitric oxide (NO) production and Malondialdehyde (MDA) content, 10 μg mL〈sup〉−1〈/sup〉 LPS could induced inflammatory response in hepatocytes. Gene expression of TLR4, NFkBp65, MAPKp38, TNF-α, IL-6 and IL-1β mRNA expression were also enhanced ex vivo (p 〈 0.05). In vivo test demonstrated that pretreatment with astaxanthin prevented the LPS-induced upregulation of pro-inflammatory cytokines TNF-α, IL-6 and IL-1β. Besides, astaxanthin blocked the expression of Toll-like receptor 4 (TLR4) and then suppressed the phosphorylation of nuclear transcription factor-kappa B (NF-κB) p65 and degradation inhibitor of NF-κBα (IκBα). Further study showed that astaxanthin could suppress the phosphorylation of p38, extracellular signal-regulated kinase (ERK) and c-jun NH2-terminal kinase (JNK) in mitogen-activated protein kinase (MAPK) signal pathway. In conclusion, our results suggest that astaxanthin played an anti-inflammatory role by regulating TLR4 and the NF-κB and MAPK signaling pathways in 〈em〉C. argus〈/em〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Tiantian Gu, Lu Lu, Chen An, Bowen Chen, Wenzhi Wei, Xinsheng Wu, Qi Xu, Guohong Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉RIG-I-like receptors (RLRs), as key cytoplasmic sensors of viral pathogen-associated molecular patterns, can recognise viral RNA and enhance the antiviral response. Some investigations have focused on the roles of RLRs in the innate immune response in grass carp, large yellow croaker, and rainbow trout. However, little is known about the function of RLRs in mandarinfish (〈em〉Siniperca chuatsi〈/em〉), an important economic fish in Perciformes. Here, we functionally characterized the RLRs involved in the immune responses of mandarinfish (〈em〉Siniperca chuatsi〈/em〉), by evaluating three RLRs, namely, 〈em〉RIG-I〈/em〉, 〈em〉MDA5〈/em〉, and 〈em〉LGP2〈/em〉. The results revealed that 〈em〉MDA5〈/em〉 and 〈em〉LGP2〈/em〉 were present in mandarinfish, whereas 〈em〉RIG-I〈/em〉 was absent. The 〈em〉MDA5〈/em〉 and 〈em〉LGP2〈/em〉 cDNA sequences contained 2976 and 2046 bp and encoded 991 and 681 amino acids, respectively. Multiple sequence alignments showed that 〈em〉MDA5〈/em〉 and 〈em〉LGP2〈/em〉 of mandarinfish were clustered together with their homologs from other teleost fishes and shared high similarities with those from other vertebrates, and 〈em〉RIG-I〈/em〉 of mandarinfish was absent. Moreover, quantitative real-time PCR (qPCR) analysis suggested that 〈em〉MDA5〈/em〉 and 〈em〉LGP2〈/em〉 were constitutively expressed in all tissues tested, and 〈em〉MDA5〈/em〉 mRNA expression was relatively high in the gill, and spleen, whereas 〈em〉LGP2〈/em〉 mRNA expression was high in the liver, gill, and head kidney. After stimulation with lipopolysaccharide or poly I:C, the expression of 〈em〉MDA5〈/em〉 and 〈em〉LGP2〈/em〉 was upregulated in spleen, gill and head kidney, but the pattern was not exactly the same, 〈em〉MDA5〈/em〉 transcripts generally increased and then declined with the prolonged infection, while 〈em〉LGP2〈/em〉 transcripts went up continuously, which showed that mandarinfish MDA5 and LGP2 may play independent roles in antiviral response. Besides, it is further revealed that the 〈em〉MDA5〈/em〉 could activate NF-κB and IRF3 to inducing the production of IFN-β by constructing tet-on stable strain of 293T cell, however over-expression of LGP2 resulted in decreased NF-κB, IRF3 and IFN-β production in cells challenged with LPS and polyI:C Taken together, our results demonstrated that 〈em〉MDA5〈/em〉 and 〈em〉LGP2〈/em〉, as a positive and negative regulator, respectively, played an important role in modulating antibacterial andantiviral immune responses though activating NF-κB and IRF3 in RLRs signaling of mandarinfish.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Thavasimuthu Citarasu, Chinnadurai Lelin, Mariavincent Michael Babu, Setty Balakrishnan Anand, Abel Arul Nathan, Vikram N. Vakharia〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉White Tail Disease (WTD) is one of the important viral diseases of fresh water giant prawn 〈em〉Macrobrachium rosenbergii,〈/em〉 which is caused by 〈em〉Macrobrachium rosenbergii〈/em〉 nodavirus (〈em〉Mr〈/em〉NV). In the present study, the capsid protein gene of 〈em〉Mr〈/em〉NV containing a His-tag was cloned into a baculovirus vector pVL1393 and expressed the recombinant 〈em〉Mr〈/em〉NV protein in insect cells, using a baculovirus expression system. A band corresponding to the 〈em〉Mr〈/em〉NV protein of 43 kDa was characterized after fractionating the proteins of baculovirus-infected cell lysates by SDS-polyacrylamide gel, and immunostaining with His-tag monoclonal antibody. Furthermore, purified 〈em〉Mr〈/em〉NV capsid protein assembled into virus-like particles (VLPs) of ∼30 nm in diameter, when examined by transmission electron microscopy (TEM). To vaccinate the larvae by oral route, the recombinant 〈em〉Mr〈/em〉NV (r-〈em〉Mr〈/em〉NV) protein was coated with artificial prawn feed and fed to 〈em〉M. rosenbergii〈/em〉 larvae (90 ± 10 mg) for 60 days. After 30 and 60 days of vaccine treatment, group of prawns were challenged with virulent 〈em〉Mr〈/em〉NV orally. Samples were collected at different time intervals to evaluate the survival of larvae and to analyze the presence of 〈em〉Mr〈/em〉NV by double-step PCR and expression of immune/ toll-like receptor (TLR) genes. Non-vaccinated group of 〈em〉M. rosenbergii〈/em〉 larvae succumbed to death and had 90% mortality, whereas the r-〈em〉Mr〈/em〉NV protein treated groups exhibited 65 and 80% survival (P  ≤  0.001) for 30 and 60 days post-vaccination (dpv), respectively. Double-step PCR diagnosis revealed that there was 100% positive signals observed in non-vaccinated prawn group, whereas the infection was reduced significantly (P 〈 0.001) to 32 and 17% respectively in 30 and 60 dpv. Among the four different immune/ TLR genes such as antimicrobial peptide (〈em〉Mr〈/em〉amp), lysozyme (〈em〉Mr〈/em〉LY), proPhenol Oxidase (〈em〉Mr〈/em〉PPO) and Toll-Like Receptor (〈em〉Mr〈/em〉Toll) expression screening, 〈em〉Mr〈/em〉amp was successfully expressed in the 〈em〉Mr〈/em〉NV subunit protein vaccinated prawns, whereas the non-vaccinated prawn had no immune/TLR gene expression. Taken together, our results demonstrate that oral vaccination of 〈em〉M. rosenbergii〈/em〉 larvae with baculovirus-expressed 〈em〉Mr〈/em〉NV capsid protein confer up to 78% protection against 〈em〉Mr〈/em〉NV infection.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S105046481830809X-fx1.jpg" width="269" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Gunapathy Devi, Ramasamy Harikrishnan, Bilal Ahmad Paray, Mohammad K. Al-Sadoon, Seyed Hossein Hoseinifar, Chellam Balasundaram〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In aquaculture and human health care probiotics and prebiotics have been widely used due to their important role in enhancing beneficial gut microbiota, promoting growth, increasing disease resistance, and positively modulating the host immune system. This study reports for the first time a comparative analysis on the effect of the probiotics and prebiotics on growth, digestive enzymes activity, antioxidant activity, and immune response in 〈em〉Channa punctatus〈/em〉 against 〈em〉Aphanomyces invadans〈/em〉. Among the diets enriched with 〈em〉Saccharomyces cerevisiae〈/em〉 (〈em〉S. cerevisiae〈/em〉) and Galactooligosaccharide (GOS) in 〈em〉C. punctatus,〈/em〉 feeding 2.5 g kg〈sup〉−1〈/sup〉 diet did not significantly influence the mean weight gain (MWG) between weeks 2 and 4 in both the infected and control groups; however the increase in MWG became significant from weeks 6–8. Similarly, during this period the protein efficiency ratio (PER), feed conversion ratio (FCR) and protein intake (PI) did not increase significantly. The intestinal protease, lipase, and amylase enzyme activities also did not increase significantly between weeks 2 and 4, whereas the values increased significantly after 6 weeks in both groups when fed with dietary supplementation of 〈em〉S. cerevisiae〈/em〉 and GOS. The total 〈em〉S. cerevisiae〈/em〉 count significantly increased in the gut of infected and non-infected fish fed with 〈em〉S. cerevisiae〈/em〉 and GOS diets while the total bacterial (TB) count decreased between weeks 6 and 8. The total superoxide dismutase (t-SOD) activity and the malonaldehyde (MDA) concentration increased significantly in the non-infected fish fed with 〈em〉S. cerevisiae〈/em〉 and GOS supplementation diets between weeks 6 and 8 whereas the catalase (CAT) and glutathione peroxidase (GPx) activities increased significantly only on week 8. The innate immune parameters such as plasma lysozyme, acid phosphatase (ACP), and myeloperoxidase (MPO) activities increased significantly in the infected and non-infected fish fed with 〈em〉S. cerevisiae〈/em〉 and GOS containing diets after 6 weeks. Similarly, the plasma nitric oxide (NO) level and total protein (TP) content significantly increased in the non-infected fish fed with 〈em〉S. cerevisiae〈/em〉 and GOS containing diets between weeks 6 and 8. In the control and the non-infected fish fed with 〈em〉S. cerevisiae〈/em〉 and GOS enriched diets caused no mortality whereas 15% and 10% mortality was observed in the infected fish fed with 〈em〉S. cerevisiae〈/em〉 and GOS diets, respectively. This study indicates that the infected and non-infected 〈em〉C. punctatus〈/em〉 fed with dietary supplementation of GOS diet at 2.5 g kg〈sup〉−1〈/sup〉 had exhibited better growth performance, digestive enzyme activities, gut microbiota composition, and immune response than that of 〈em〉S. cerevisiae〈/em〉 diet.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Qi-Lin Zhang, Xin-Yu Ji, Hong-Wei Li, Jun Guo, Feng Wang, Xian-Yu Deng, Jun-Yuan Chen, Lian-Bing Lin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Amphioxus is a key model for studying comparative immunity of vertebrates. Circular RNA (circRNA), as RNAs with a circular structure, has received little attention until recently, where several studies have reported that circRNA expression changes are involved in the immune response in animals. However, circRNA and its immune role in amphioxus have not been previously studied. Here, circRNAs in Chinese amphioxus (〈em〉Branchiostoma belcheri〈/em〉) were sequenced, and 1859 circRNAs were identified using two algorithms (find_circ and CIRI). The analysis of miRNA target sites on circRNAs showed that 332 circRNAs may function as miRNA sponges. Furthermore, we identified circRNAs that were conserved between 〈em〉B. belcheri〈/em〉 and vertebrates, tracing the origin of these circRNAs within chordates. Additionally, in combination with several key antiviral immune (poly(I:C), pIC) pathways identified in our previous 〈em〉B. belcheri〈/em〉 studies, nine circRNAs potentially involved in these pathways were identified using bioinformatic predictions. Among these nine circRNAs, eight were selected to examine their expression response in 〈em〉B. belcheri〈/em〉 challenged by pIC in comparison to control using real-time quantitative PCR. The results showed that four circRNAs were induced as part of the antiviral response against pIC, while expression of two circRNAs was decreased, and the expression levels of the remaining two were not significantly altered after pIC challenge. This work is the first to identify circRNAs and reveal their antiviral role in amphioxus. Therefore, it opens a new window to explore the comparative immunology of circRNAs in chordates and the regulatory roles of circRNAs in antiviral immunity in amphioxus.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Xiazi Huang, Bochao Hu, Xiaodong Yang, Licai Gong, Jingyun Tan, Li Deng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Piscidins are important components in protecting microbial infections in teleost. The present study purified and identified a truncated peptide, whose sequence was very close to that of putative mature peptide of epinecidin-1 (piscidin-1) in orange-spotted grouper (〈em〉Epinephelus coioides〈/em〉), Epi-1 (also named as short form of ecPis-1, ecPis-1S). The immunomodulatory effects of ecPis-1S on splenic lymphocytes of orange-spotted grouper were explored 〈em〉in vitro〈/em〉. The transcriptome study was carried out by 〈em〉De novo〈/em〉 transcriptome sequencing (RNA-Seq) in splenic lymphocytes of orange-spotted grouper. Regarding the profiles of gene expressions, 2994 genes were up-regulated and 2679 genes were down-regulated in the splenic lymphocytes stimulated by ecPis-1S. In the case of differential expression genes, 330 genes were involved in immune related pathways. Among them, 34 genes were involved in T cell receptor signaling pathway, 31 genes in natural killer cell mediated cytotoxicity and 23 genes in leukocyte transendothelial migration, respectively. Immune-related genes selected for qRT-PCR verification, such as interleukin-1β (〈em〉il-1b〈/em〉), tumor necrosis factor α (〈em〉tnfa〈/em〉), T cell antigen receptor (〈em〉tcr〈/em〉), major histocompatibility complex class I (〈em〉mhc I〈/em〉), and 〈em〉mhc II〈/em〉 were significantly up-regulated by ecPis-1S (p 〈 0.05). ecPis-1S could significantly enhance the proliferation of splenic lymphocytes of orange-spotted grouper 〈em〉in vitro〈/em〉 (p 〈 0.05). In addition, the result of qRT-PCR revealed that ecPis-1S also significantly up-regulated cell cycle-related genes, including cyclin A (〈em〉cyca〈/em〉), cyclin-dependent kinase 2 (〈em〉cdk2〈/em〉), 〈em〉cdk4〈/em〉, cell division cycle protein 6 (〈em〉cdc6〈/em〉), and transforming growth factor β (〈em〉tgfb〈/em〉) (p 〈 0.05), which suggested that ecPis-1S promoted the proliferation of lymphocytes by activating cell division cycle. In conclusion, the results indicated that the mature peptide of piscidin-1 in orange-spotted grouper could act as immune modulator and play an important role in regulation of the immune response in fish.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Yuxiong Lai, Min Liang, La Hu, Zicheng Zeng, Hai Lin, Gao Yi, Ming Li, Zhaoyu Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉RIG-I-like receptors (RLRs) play a key role in antiviral and inflammatory responses. Increasing evidence indicates that ubiquitination is crucial for regulation of RIG-I signaling pathway. Several ubiquitin ligases were reported to be involved in RIG-I-mediated signal transduction. In the present study, we demonstrated zebrafish RING finger protein 135 (zbRNF135) was a critical player in the regulation of RIG-I signaling pathway. 〈em〉zbRNF1〈/em〉35 mRNA was widely expressed in different tissues of zebrafish. The expression of 〈em〉zbRNF135〈/em〉 was up-regulated post poly(I:C) treatment 〈em〉in vivo〈/em〉 and in 〈em〉vitro〈/em〉. Furthermore, the expression profiles of RIG-I signaling pathway related genes (〈em〉LGP2〈/em〉, 〈em〉MDA5〈/em〉, 〈em〉RIG-I〈/em〉, 〈em〉MAVS〈/em〉, 〈em〉TRAF3〈/em〉, 〈em〉IRF3〈/em〉 and 〈em〉IRF7〈/em〉), together with its downstream molecules (〈em〉IFN1〈/em〉, 〈em〉ISG15〈/em〉, 〈em〉Mx〈/em〉 and 〈em〉PKR〈/em〉), were up-regulated by overexpression of zbRNF135 in ZF4 cells. Luciferase and ubiquitination assays revealed that overexpression of zbRNF135 facilitated zebrafish RIG-I (zbRIG-I)-mediated IFN1 promoter activation by mediating K63-linked ubiquitination of zbRIG-I. The co-immunoprecipitation assay showed that zbRNF135 specifically interacted with zbRIG-I. Our study indicated that zbRNF135 participated in innate immune response through modulating RIG-I signaling pathway.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Yu-Ling Su, Guo Chen, Liang-Shi Chen, Jia-Zhou Li, Gang Wang, Jia-Yang He, Tian-Yong Zhan, Yan-Wei Li, Mu-Ting Yan, You-Hua Huang, Qi-Wei Qin, Xue-Ming Dan, Hong-Yan Sun〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Antimicrobial peptides (AMPs) are small proteins showing broad-spectrum antimicrobial activity that have been known to be powerful agents against a variety of pathogens (bacteria, fungi and viruses). In this study, the effects of AMPs from 〈em〉Bacillus subtilis〈/em〉 on 〈em〉Epinephelus coioides〈/em〉 were examined. 〈em〉E. coioides〈/em〉 were fed with diets containing AMPs (0, 100, 200, 400 or 800 mg/kg) for four weeks. Results showed that the levels of total protein (TP), albumin (ALB), alanine aminotransferase (ALT), aspartate aminotransferase (AST), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and blood glucose (GLU) and lipopolysaccharide (LPS) in the serum of 〈em〉E. coioides〈/em〉 changed than those of the control group; compared to the control group, the levels of total antioxidant capacity (T-AOC), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and lysozyme (LZM) levels in 〈em〉E. coioides〈/em〉 fed with different dosages AMP diets were also different; in addition, the mRNA expression of tumor necrosis factor alpha (TNF-α), interleukin-1-beta (IL-1β), and heat shock protein 90 (Hsp90) in the tissues of 〈em〉E. coioides〈/em〉 were measured, the three genes in the tissues examined were significantly upregulated. The results demonstrated that diets containing AMPs can enhance the antioxidant capacity and innate immune ability of 〈em〉E. coioides〈/em〉, indicating that AMPs might be a potential alternative to antibiotics in 〈em〉E. coioides〈/em〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Cheng Li, Lindan Sun, Hanzuo Lin, Zhendong Qin, Jiagang Tu, Jun Li, Keping Chen, Sarath Babu V, Li Lin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Autophagy is a degradation cellular process which also plays an important role in virus infection. Glutamine is an essential substrate for the synthesis of glutathione which is the most abundant thiol-containing compound within the cells and plays a key role in the antioxidant defense and intracellular signaling. There is an endogenous cellular glutathione pool which consists of two forms of glutathione, i.e. the reduced form (GSH) and the oxidized form (GSSG). GSH serves as an intracellular antioxidant to maintain cellular redox homeostasis by scavenging free radicals and other reactive oxygen species (ROS) which can lead to autophagy. Under physiological conditions, the concentration of GSSG is only about 1% of total glutathione, while stress condition can result in a transient increase of GSSG. In our previous report, we showed that the replication of snakehead fish vesiculovirus (SHVV) was significant inhibited in SSN-1 cells cultured in the glutamine-starvation medium, however the underlying mechanism remains enigmatic. Here, we revealed that the addition of L-Buthionine-sulfoximine (BSO), a specific inhibitor of the GSH synthesis, could decrease the 〈em〉γ-〈/em〉glutamate-cysteine ligase (GCL) activity and GSH levels, resulting in autophagy and significantly inhibition of the replication of SHVV in SSN-1 cells cultured in the complete medium. On the other hand, the replication of SHVV was rescued and the autophagy was inhibited in the SSN-1 cells cultured in the glutamine-starvation medium supplemented with additional GSH. Furthermore, the inhibition of the synthesis of GSH had not significantly affected the generation of reactive oxygen species (ROS). However, it significantly decreased level of GSH and enhanced the level of GSSG, resulting in the decrease of the value of GSH/GSSG, indicating that it promoted the cellular oxidative stress. Overall, the present study demonstrated that glutamine starvation impaired the replication of SHVV in SSN-1 cells via inducing autophagy associated with the disturbance of the endogenous glutathione pool.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Han-Mei Ye, Tao Zhao, Li-Xiang Wu, Jie Cheng, Xiao-Ying Tan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Suppressors of cytokine signaling (SOCS) are important molecules that mediates the regulation of glucose homeostasis. Here, we cloned and characterized the full-length cDNA sequences of nine genes of the SOCS family (SOCS1, 2, 3, 3b, 5, 5b, 6, 7 and CISH) from yellow catfish 〈em〉P. fulvidraco〈/em〉, explored their mRNA abundance across the tissues and their mRNA changes to dietary carbohydrate levels. Structural analysis indicated that the nine members shared conserved functional domains to the orthologues of the mammalian SOCS members, such as SRC homology 2 and the SOCS domains. Their mRNAs were constitutively expressed in various tissues but changed among the tissues〈em〉.〈/em〉 Their mRNA expression in response to dietary carbohydrate levels were explored in the liver, muscle, intestine, testis and ovary. Dietary carbohydrate addition showed significant effects on the mRNA levels of the nine SOCS members. Moreover, their mRNA expressions in response to dietary carbohydrate levels were also tissue-dependent. These indicated that SOCS members potentially mediated the utilization of dietary carbohydrate in yellow catfish.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Regla Medina-Gali, Melissa Belló-Pérez, Sergio Ciordia, María Carmen Mena, Julio Coll, Beatriz Novoa, María del Mar Ortega-Villaizán, Luis Perez〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To better understand spring viremia of carp virus (SVCV) pathogenesis in zebrafish proteomic analysis was used to examine the plasma protein profile in SVCV-infected zebrafish. A total of 3062 proteins were identified. Of those 137, 63 and 31 proteins were enriched in blood samples harvested at 1, 2 and 5 days post SVCV infection, respectively. These altered host proteins were classified based on their biological function: 23 proteins under the response to stimulus term were identified. Interestingly, at the top of the up-regulated proteins during SVCV infection were the proteins of the vitellogenin family (Vtg) and the grass carp reovirus-induced gene (Gig) proteins. Real-time RT-PCR evaluation of samples from internal organs verified that SVCV infection induced 〈em〉vtg〈/em〉 and 〈em〉gig2〈/em〉 gene expression already at day 1 post-infection. Western blot analysis revealed the presence of Vtg protein only in blood of SVCV-infected fish. This is the first proteomic study to reveal the involvement of Vtg proteins in adult fish response to viral challenge. It also highlights the role of Gig proteins as important factors in antiviral response in fish. This work provides valuable relevant insight into virus-host interaction and the identification of molecular markers of fish response to virus.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1050464818308416-fx1.jpg" width="291" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Patrick C. Blaufuss, T. Gibson Gaylord, Wendy M. Sealey, Madison S. Powell〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The current study examines expression of S100 genes, a group of calcium-sensing proteins poorly characterized in fishes. In mammals, these proteins are known to play roles beyond calcium-signaling, including mediation of inflammatory processes. Some S100 proteins also serve as biomarkers for a variety of autoinflammatory conditions. It is well known that salmonids exhibit varying degrees of intestinal enteritis when exposed to alternative feed ingredients containing antinutritional factors, with soybean meal (SBM) being one of the best characterized. The etiology of soy-caused distal enteritis isn't entirely understood but displays similar histopathological alterations to the gut observed in human mucosal inflammatory bowel diseases. We sought to determine if teleost S100 genes show a concomitant response like that observed in mammals, utilizing rainbow trout fed high-soy diets as a model for intestinal inflammation. We examined expression of fourteen known salmonid S100 genes in the liver, first segment of the mid-intestine (proximal intestine), and second segment of the mid-intestine (distal intestine). After 12 weeks on a high-soy diet containing 40% SBM, we observed upregulation of several S100 genes in the distal intestine (S100I2, A10a, V1, V2, and W), no changes in the proximal intestine, and downregulation of S100V2 in the liver. Overall, our results provide further knowledge of the expression of S100 genes and provide targets for future research regarding inflammatory processes in the rainbow trout gut.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Geng Chen, Lv Xiong, Yumeng Wang, Libo He, Rong Huang, Lanjie Liao, Zuoyan Zhu, Yaping Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Grass carp is an important fish species in Chinese aquaculture, and can be afflicted by a hemorrhagic disease caused by the grass carp reovirus (GCRV). Interestingly, the affects of GCRV infection of grass carp are age-restricted, meaning that one-year-old grass carp can be infected and can suffer hemorrhagic disease, but three-year-old carp are not so afflicted. In this study, we investigated the mechanism responsible for this age-restricted pathology. We evaluated the relative copy number of GCRV RNA, the expression levels of proteins in blood, and changes in DNA methylation in carp from the two age groups after infection with GCRV. After GCRV infection, the relative copy number of GCRV RNA in three-year-old grass carp was significantly lower than in one-year-old carp. The differences in circulating protein levels mainly occurred in concentrated in complement and coagulation proteins, and the expression levels of these proteins were significantly higher in three-year-old grass carp than in one-year-old carp. Moreover, the expression levels of DNA methylation-related genes in the liver and spleen of one-year-old grass carp were significantly higher than those of three-year-old carp. These results suggested that as age of grass carp increases, faster and more efficient response of the immune system after viral infection, especially the complement system, and differences in DNA methylation may be important factors that affect the age restriction observed in GCRV infection. Our study provides new insights into the mechanisms underlying age restriction of GCRV infection.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Yanxian Li, Trond M. Kortner, Elvis M. Chikwati, Hetron Mweemba Munang'andu, Erik-Jan Lock, Åshild Krogdahl〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Limited availability of sustainable feed ingredients is a serious concern in salmon aquaculture. Insects may become an important, sustainable resource for expanding the raw material repertoire. Herein, we present data from an 8-week feeding trial with pre-smolt Atlantic salmon (initial body weight 49 ± 1.5 g) fed either a reference diet containing fish meal, soy protein concentrate and wheat gluten as protein sources, or a test diet wherein 85% of the protein was supplied by black soldier fly larvae meal. Possible diet effect on the systemic immune response was evaluated by measuring plasma antibody titers after vaccination against infectious pancreatic necrosis virus (IPNV). The gut health of fish was evaluated using endpoints including organ and tissue indices, histopathological parameters and gene expression. Both diets induced the same level of antibody responses against IPNV. In fish fed the reference diet, the histological examination of the pyloric caeca mucosa showed clear hyper-vacuolization suggestive of lipid accumulation in enterocytes, whereas this was less pronounced in the insect meal fed fish. Expression of genes relevant to lipid metabolism confirmed these histological findings. Immune and barrier-function gene expression profiles were both generally not affected by diet. However, the fish fed insect meal showed increased expression of genes indicative of stress response, immune tolerance and increased detoxification activity. In summary, our results showed no indications that dietary inclusion of insect meal affected the gut health of Atlantic salmon negatively. The insect meal based diet seemed to reduce excessive lipid deposition in the pyloric caeca and stimulate xenobiotic metabolism.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Dongdong Li, Hongtao Nie, Shasha Dong, Zhongming Huo, Xiwu Yan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Manila clam, 〈em〉Ruditapes philippinarum〈/em〉, is one of the most commercially important marine bivalves. C-type lectins (CTLs) are pattern recognition receptors (PRRs) that play important roles in the identification and elimination of pathogens by the innate immune system. In this study, a new CTL (RpCTL) was identified in the Manila clam, 〈em〉R. philippinarum〈/em〉. The full-length RpCTL cDNA is 802 bp, with an open reading frame of 591 bp, encoding 196 amino acids, including an N-terminal signal peptide and a carbohydrate recognition domain (CRD). RpCTL contains conserved CRD disulfide bonds involving four cysteine residues (Cys〈sup〉30〈/sup〉–Cys〈sup〉104〈/sup〉, Cys〈sup〉124〈/sup〉, and Cys〈sup〉132〈/sup〉), and the EPN (Glu〈sup〉94〈/sup〉–Pro〈sup〉95〈/sup〉–Asn〈sup〉96〈/sup〉) and WND (Trp〈sup〉119〈/sup〉–Asn〈sup〉120〈/sup〉–Asp〈sup〉121〈/sup〉) motifs. Quantitative reverse transcription (RT)–PCR detected 〈em〉RpCTL〈/em〉 transcripts mainly in the gill, siphon, and hepatopancreas in three shell-color strains (zebra, white, and white–zebra strains) and two unselected populations of 〈em〉R. philippinarum〈/em〉, and the gene was highly expressed in the hepatopancreas after lipopolysaccharide treatment. Antimicrobial activity assays of recombinant RpCTL against both Gram-positive and Gram-negative bacteria showed that RpCTL inhibits microorganismal growth. In a survival test, RpCTL inhibited and killed 〈em〉Vibrio anguillarum〈/em〉 in 〈em〉R. philippinarum〈/em〉. These results suggest that RpCTL participates in the pathogen identification process of 〈em〉R. philippinarum〈/em〉 as a PRR and in its immune defense system.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Jiajie Zhu, Min Wei, Quanhe wang, Qiuwei Ao, Yun Tan, Yongju Luo, Hui Wang, Hesheng Jiang, Qiaomu Hu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In mammals, Galectin-3 has been revealed to be widely expressed in immune cells and played important role in immune reactions. However, Galectin-3 is frequently less reported in teleost. In the present study, a molecular characterization and expression analysis of 〈em〉galectin-3〈/em〉 were conducted in GIFT strain Nile tilapia. The full-length cDNA is 1034 bp with 690 bp of protein coding sequences. The result of qRT-PCR showed that the mRNA of 〈em〉galectin-3〈/em〉 was widely expressed in various tissues (heart, liver, spleen, gill, kidney, brain, intestine, skin, muscle, and ovary), and the higher expression was observed in immune-related tissues (liver and spleen). The time-course expression analysis revealed that 〈em〉galectin-3〈/em〉 was significantly up-regulated in intestine (5 h, 50 h, and 7 d), liver (5 h, 50 h, and 7 d), spleen (5 and 50 h), head-kidney (5 and 50 h), gill (5 h and 7 d) after 〈em〉Streptococcus agalactiae〈/em〉 challenge, and significantly up-regulated in intestine (18, 24, 36, 72, and 96 h), liver (6, 18, 24, 96 h, and 6 d), spleen (18, 24, 36, 72, and 96 h), head-kidney (6, 12, 18, 24, 36, 72, and 96 h), and gill (12, 18, 24, and 36 h) after 〈em〉Aeromonas hydrophila〈/em〉 challenge. Taken together, these data suggest that 〈em〉galectin-3〈/em〉 plays a role in immune responses in Nile tilapia after bacterial challenge.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Shengming Sun, Ying Wu, Han Yu, Yanli Su, Mingchun Ren, Jian Zhu, Xianping Ge〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Dietary protein plays a major role in determining the rate of fish growth and overall health. Given that the liver is an important organ for metabolism and detoxification, we hypothesized that optimal dietary protein levels may benefit liver function. Herein, we investigated the effects of dietary protein level on serum biochemistry, liver histology and transcriptome profiling of juvenile bighead carp 〈em〉Aristichthys nobilis〈/em〉 fed for 8 weeks on a diet supplemented with high protein (HP, 40%), low protein (LP, 24%) or optimal protein (OP, 32%; controls). The results revealed a significant change in liver morphology in LP and HP groups compared with the OP group, coupled with increased serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity. RNA sequencing (RNA-Seq) analysis of the liver transcriptome yielded 47 million high-quality reads using an Illumina platform, which were 〈em〉de novo〈/em〉 assembled into 80,777 unique transcript fragments (unigenes) with an average length of 1021 bp. Subsequent bioinformatics analysis identified 878 and 733 differentially expressed unigenes (DEGs) in liver in response to LP and HP diets, respectively. KEGG enrichment analysis of DEGs identified immune and metabolism-related pathways, including Toll-like receptor signaling, PI3K-Akt signaling, NF-κB signaling, complement and coagulation, peroxisome, nitrogen metabolism, PPAR signaling, and glycolysis and gluconeogenesis pathways. Transcriptome profiling results were validated by quantitative real-time PCR for 16 selected DEGs. The findings expand our understanding of the molecular mechanisms underlying the effects of dietary protein level on liver function in bighead carp.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): M.A. Rahman, S. Henderson, P. Miller-Ezzy, X.X. Li, J.G. Qin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Summer mortality of some bivalve species is often associated with the change of environmental temperature. This study compares the response of immunological parameters to temperature change in three marine bivalves: Pacific oyster 〈em〉Crassostrea gigas〈/em〉, Mediterranean mussel 〈em〉Mytilus galloprovincialis〈/em〉 and mud cockle 〈em〉Katelysia rhytiphora〈/em〉. Each species was exposed to three temperatures, 15 °C, 20 °C and 25 °C for 14 days. The total haemocyte count (THC), phagocytosis, reactive oxygen species (ROS) and the activity of antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT) were used as indicators to measure the response of each species to different temperatures. The highest temperature (25 °C) significantly increased the THC and phagocysis of haemocytes in all species. The SOD and CAT activities in the haemocytes of 〈em〉M. galloprovincialis〈/em〉 and 〈em〉K. rhytiphora〈/em〉 rapidly increased with temperature elevation, concomitantly with the increase of ROS ions. In contrast, the increases of ROS and SOD in 〈em〉C. gigas〈/em〉 only occurred from 20 °C to 25 °C, suggesting that this intertidal species is more adaptive to different temperature levels. This study indicates that the activities of antioxidant enzymes can reflect the immune response of marine bivalves to thermal stress. Intertidal species such as Pacific oysters have a greater tolerance to thermal stress than subtidal species (e.g. Mediterranean mussel) and demersal species buried in sand (e.g. cockle).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Jingliang Huang, Liping Xie, Rongqing Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The pearl oyster 〈em〉Pinctada fucata〈/em〉 is famous for producing luxurious pearls. As filter feeders, they are confronted with various infectious microorganisms. Despite a long history of aquaculture, diseases in 〈em〉P. fucata〈/em〉 are not well studied, which limits the development of the pearl industry. We report here a shell disease in 〈em〉P. fucata〈/em〉 and a study of the shell repair processes. Scanning electron microscopy (SEM) revealed that the nacreous layer gradually recovered from disordered CaCO〈sub〉3〈/sub〉 deposition, accompanied by a polymorphic transition from a calcite-aragonite mixture to an aragonite-dominant composition, as revealed by X-ray diffraction analysis. SEM also showed that numerous microbes were embedded in the abnormal shell layers. Similar indications were induced by a high concentration of microbes injected into the extrapallial space, suggesting the potential pathogenic effect of uncontrolled microbes. Furthermore, hemocytes were found to participate in pathogens resistance and might promote shell repair. These results further our understanding of pathogen-host interactions in pearl oysters and have implications for biotic control in pearl aquaculture.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Dong-Liang Lu, Samwel Mchele Limbu, Hong-Bo Lv, Qiang Ma, Li-Qiao Chen, Mei-Ling Zhang, Zhen-Yu Du〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Dietary α-lipoic acid (LA), β-glucan (Gluc) and 〈span〉l〈/span〉-carnitine (L-Ca) are commonly used additives to promote fish growth and stress resistance in aquaculture production. However their mechanisms and efficiencies in helping fish to resist diseases have not been compared before. In this study, we fed Nile tilapia (〈em〉Oreochromis niloticus〈/em〉) with diets containing appropriate doses of LA, Gluc and L-Ca for five weeks and further intraperitoneally injected the fish with 〈em〉Aeromonas hydrophila〈/em〉. After dietary treatment, none of the additives affected the fish growth, but dietary Gluc and L-Ca reduced protein and lipid body contents in fish, respectively. After 〈em〉A. hydrophila〈/em〉 challenge, all fish treated with the three dietary additives showed higher survival rate, but those fed on dietary L-Ca had lower survival than those fed on LA and Gluc diets, indicating high protection efficiency of LA and Gluc. The protective mechanisms of the three feed additives were quite different under 〈em〉A. hydrophila〈/em〉 infection. Dietary LA induced higher total antioxidant capacity and higher mRNA expression of anti-oxidative genes than other additives in liver and also activated partly the immune function in serum and spleen. Gluc largely increased the immune function by activating the immunity enzymes in serum, inducing inflammation in liver and increasing the expression of immune genes in spleen and head kidney. Gluc also increased partly the antioxidant capacity in serum and liver and lipid catabolism in liver. L-Ca largely increased lipid catabolism in liver while it increased partly the antioxidant capacities in serum and liver. Taken together, these results indicate that, dietary LA, Gluc and L-Ca have various protective mechanisms and differ in their efficiencies on resisting 〈em〉A. hydrophila〈/em〉 infection in Nile tilapia.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Bin Shen, Ke Wei, Shaoyu Guo, Cheng Liu, Jianshe Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, we sequenced and characterized two homologues of interferon-stimulated gene ISG15, termed as LcISG15-1 and LcISG15-2, from the large yellow croaker (〈em〉Larimichthys crocea〈/em〉). The LcISG15-1 encodes 159 amino acids and the LcISG15-2 encodes 155 amino acids, both of which contain two tandem ubiquitin-like domains and the conserved C-terminal LRGG conjugation motif. The sequence analyses showed that both the LcISG15-1 and LcISG15-2 exhibit high similarity with ISG15 from other fishes. A putative IFN-stimulatory response element (ISRE) was detected in promoter regions of both the LcISG15-1 and LcISG15-2. Phylogenetic analyses revealed a close evolutionary relationship of both the LcISG15-1 and LcISG15-2 with other teleostean ISG15. Molecular evolutionary analyses suggested a gene duplication event of ISG15 in the ancestor of the Sciaenidae, with a signature of positive selection was found in the ISG15-2 gene copy of sciaenid fishes. The Real-time PCR analyses showed that the LcISG15-1 and LcISG15-2 were both found to be ubiquitously expressed in ten examined organs in large yellow croaker, with predominant expressions both in peripheral blood. Expression analyses showed that both the LcISG15-1 and LcISG15-2 were rapidly and significantly upregulated 〈em〉in vivo〈/em〉 after poly (I:C) challenge in liver and spleen organs. However, the LcISG15-1 and LcISG15-2 were both significantly induced after pathogen 〈em〉Vibrio parahemolyticus〈/em〉 infection only in the liver but not in the spleen. These results indicated that there are two ISG15 homologues in the large yellow croaker, both of which are likely to be involved in host immune defense against viral and bacterial infection.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Yuhang Hong, Yi Huang, Guangwen Yan, Chao Pan, Jilei Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As a broad-spectrum herbicide, glyphosate was extensively utilised in China for several decades. The contradiction between glyphosate spraying and crab breeding in the rice-crab co-culture system has become more obvious. In this study, the antioxidative status and immunological responses of Chinese mitten crab, 〈em〉Eriocheir sinensis,〈/em〉 under sublethal exposure of glyphosate were investigated by detecting the antioxidative and immune-related enzyme activity, acetylcholinesterase (AChE) activity and relative mRNA expression of heat shock proteins (HSPs) in hepatopancreas. The results showed that high concentrations of glyphosate (44 and 98 mg/L) could induce significant alteration of superoxide dismutase (SOD), peroxidase (POD), acid phosphatase (ACP), alkaline phosphatase (AKP), and phenoloxidase (PO) activities by first rising then falling during the exposure. However, AChE activity in all treatments including 4.4 mg/L was inhibited markedly after 6 h of exposure. In addition, the relative mRNA expression of HSP 60, HSP 70, and HSP 90 was significantly upregulated at both 48 h and 96 h. These results revealed that glyphosate has a prominent toxic effect on 〈em〉E. sinensis〈/em〉 based on antioxidative and immunological response inhibition and AChE activity reduction even at the lowest concentration of 4.4 mg/L, and a protective response by upregulation of HSPs was carried out by the species to ease the environmental stress.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Hongquan Wang, Chunhua Ding, Jing'an Wang, Xin Zhao, Shengzhen Jin, Jian Liang, Hong Luo, Dongfang Li, Rui Li, Yaoguo Li, Tiaoyi Xiao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The grass carp reovirus (GCRV) has been shown to cause lethal infections in the grass carp 〈em〉Ctenopharyngodon idella〈/em〉 (〈em〉C. idella〈/em〉). In order to investigate the immune response to GCRV infection, the full-length cDNA sequences of 〈em〉coagulation factor VIII〈/em〉 (〈em〉CiFVIII〈/em〉) and 〈em〉plasminogen〈/em〉 (〈em〉CiPLG〈/em〉) from 〈em〉C〈/em〉. 〈em〉idella〈/em〉 were cloned and their involvement in the immune response was studied. The immunity factor levels in 〈em〉C〈/em〉. 〈em〉idella〈/em〉 with different GCRV resistances were also analyzed. The full-length 2478 bp cDNA of 〈em〉CiFVIII〈/em〉 contained an open reading frame of 1965 bp and encoded a putative polypeptide of 654 amino acid residues. The full-length 2907 bp cDNA of 〈em〉CiPLG〈/em〉 contained an open reading frame of 2133 bp and encoded a putative polypeptide of 710 amino acid residues. 〈em〉CiFVIII〈/em〉 was closely clustered with that of 〈em〉Clupea harengus〈/em〉. 〈em〉CiPLG〈/em〉 was first clustered with those of 〈em〉Cyprinus carpio〈/em〉 and 〈em〉Danio rerio〈/em〉. 〈em〉CiFVIII〈/em〉 transcripts were most abundant in the liver and least in the skin. The highest expression level of 〈em〉CiPLG〈/em〉 was observed in liver and the lowest in muscle. Expression levels of 〈em〉CiFVIII〈/em〉 in gill, head kidney and spleen, and expression levels of 〈em〉CiPLG〈/em〉 in gill, intestine and liver all reached the maximum at 72 h post GCRV infection. In spleen, expression levels of 〈em〉CiFVIII〈/em〉 and 〈em〉CiPLG〈/em〉 were significantly positively correlated. The activities of T-AOC, LSZ and IgM in R〈em〉♂〈/em〉 were significantly higher than those in O〈em〉♂〈/em〉. Likewise, T-AOC and LSZ activities in F1 were significantly higher than f1 individuals (〈em〉P〈/em〉 〈 0.01). These results indicated that 〈em〉CiFVIII〈/em〉 and 〈em〉CiPLG〈/em〉 may play important roles in the immune response to GCRV infection. In addition, antioxidant ability and serum immune factor activity may confer a different viral resistance to 〈em〉C〈/em〉. 〈em〉idella〈/em〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Zhuanzhuan Li, Xiaomei Wang, Chengxun Chen, Jinwei Gao, Aijun Lv〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The African catfish, 〈em〉Clarias gariepinus〈/em〉, an important cultured freshwater species in many countries, possess the characteristic of high disease resistance. However, little genomic information for this character of the fish is available up to now. To address the shortfall and to better understand 〈em〉C. gariepinus〈/em〉 immune response to pathogen infection at molecular level, 〈em〉C. gariepinus〈/em〉 were challenged with potent 〈em〉A. veronii〈/em〉 and the high-throughput RNA sequencing (RNA-seq) technology were employed to produce transcriptomes from spleen. In total, an average of 46,073,372 clean reads obtained were 〈em〉de novo〈/em〉 assembled into 156,955 unigenes with an average length of 1082 bp. All of unigenes were annotated to seven public databases. Three comparisons were separately conducted between the infected groups at 3 h, 24 h, 48 h post-challenge and control group. A total of 2482 differentially expressed unigenes (DEGs) were identified. Among these, 114 immune-related DEGs were captured, including 88, 42, and 31 genes at 3 h, 24 h and 48 h after infection respectively, for analysis of expression pattern and enrichment. The 114 DEGs displayed four expression patterns by cluster analysis and they were significantly enriched in 38 pathways (q 〈 0.01) related to the immune or disease, five of which were NF-kappa B, TNF, NLR, TLR and RLR pathways. Finally, the expression levels of twelve selected immune-related DEGs involved in above five pathways were scrutinized. Seven of which were up-regulated at 3 h after infection, afterward, their expression dropped to control level. In summary, this study provides valuable transcriptome resource for understanding the defense mechanisms of 〈em〉C. gariepinus〈/em〉 in resistance to pathogens from the gene expression viewpoint, which also open up the possibility to study the immune complexity and to better comprehend the interrelationships between some immune pathways in 〈em〉C. gariepinus〈/em〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Huan Wang, Wei Tang, Rui Zhang, Shaoxiong Ding〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recently, mucosal surfaces, especially fish skin and its secreted mucus, have attracted significant interest from immunologists. 〈em〉Amphiprion clarkii〈/em〉, a member of the family Pomacentridae, lives symbiosis with sea anemones and has a good resistance to common seawater bacterial diseases and parasites owing to the protection from its abundant skin mucus. In the present work, the activity of immune-related enzymes (lysozyme, protease, antiprotease, cathepsin B, alkaline phosphatase and peroxidase), the antibacterial activity against two Gram-positive bacteria and five Gram-negative bacteria, the antiparasitic activity against the pathogen of marine white spot disease (〈em〉Cryptocaryon irritans〈/em〉 theronts) and the physico-chemical stability (to pH and heat) of the skin mucus of 〈em〉A. clarkii〈/em〉 were analysed. The results showed that the levels of lysozyme and peroxidase were very similar (from 2 to 4 U mg〈sup〉−1〈/sup〉 protein). However, cathepsin B was detected of 63.32 U mg〈sup〉−1〈/sup〉 protein and alkaline phosphatase was only 0.12 U mg〈sup〉−1〈/sup〉 protein. Moreover, protease showed a higher percentage of activity than antiprotease. 〈em〉A. clarkii〈/em〉 skin mucus showed a strong antibacterial activity against Gram-negative bacteria, particularly against 〈em〉Aeromonas hydrophila〈/em〉 and 〈em〉Vibrio parahaemolyticus〈/em〉 but showed no effect on Gram-positive bacteria at the tested concentrations. The bactericidal activity functioned within a short time in a distinct time- and dose-dependent manner. SEM showed that after treated with 〈em〉A. clarkii〈/em〉 skin mucus, the 〈em〉V. parahaemolyticus〈/em〉 cells distorted and piled together, and the filaments appeared and became into cotton-shaped or quasi-honeycomb texture to adhere cells. Meanwhile, 〈em〉A. clarkii〈/em〉 skin mucus showed an apparent antiparasitic activity against 〈em〉C. irritans〈/em〉 theronts with a distinct dose- and time-dependent relationship. LM and SEM observation showed that after treated with skin mucus, the theronts quickly stopped their swimming and cilia movement, cells became rounded, cilia shed, small bubbles formed on the surface, cell nucleolus enlarged, cytoskeleton deformed, cell membranes ruptured and cell content leaked out. Antibacterial activity was not affected by 30–90 °C heat treatment but was slightly suppressed by 100 °C. In the pH treatment groups, antibacterial activity was not affected by the moderate pH treatment of 5.0–8.0, but slightly suppressed by weak acid and weak base. Therefore, we speculated that the skin mucus of 〈em〉A. clarkii〈/em〉 might be a potential source of novel antibacterial and antiparasitic components for fish or human health-related applications. This study broadened our understanding of the role of skin mucus in the innate immune system and provided a basis for the further isolation and purification of active substances.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Christelle Langevin, Jean-Pierre Levraud, Pierre Boudinot〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tripartite motif (TRIM) family or RBCC proteins comprises characteristic zinc‐binding domains (a RING (R), a B‐box type 1 (B1) and a B‐box type 2 (B2)) and coiled‐coil (CC) domain followed by a C-terminus variable domain. There are about 80 different TRIM proteins in human, but more than 200 in zebrafish with several large gene expansions (〈em〉ftr〈/em〉 〉70 genes; 〈em〉btr〈/em〉 〉30 genes; 〈em〉trim35〈/em〉 〉 30 genes). Repertoires of 〈em〉trim〈/em〉 genes in fish are variable across fishes, but they have been remarkably diversified independently in a number of species. In mammals, TRIM proteins are involved in antiviral immunity through an astonishing diversity of mechanisms, from direct viral restriction to modulation of immune signaling and more recently autophagy. In fish, the antiviral role of TRIM proteins remains poorly understood. In zebrafish, fish specific TRIMs so called 〈em〉fintrims〈/em〉 show a signature of positive selection in the C terminus SPRY domain, reminding features of mammalian antiviral trims such as TRIM5. Expression studies show that a number of trim genes, including many 〈em〉fintrims〈/em〉, can be induced during viral infections, and may play a role in antiviral defence. Some of them trigger antiviral activity 〈em〉in vitro〈/em〉 against DNA and RNA viruses, such as FTR83 that also up-regulates the expression of type I IFN in zebrafish larvae. The tissue distribution of TRIM expression suggests that they may be involved in the regionalization of antiviral immunity, providing a particular protection to sensitive areas exposed to invading pathogens.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Peiyu Zhang, Lele Fu, Haokun Liu, Noor-Ul Huda, Xiaoming Zhu, Dong Han, Junyan Jin, Yunxia Yang, Yang-Su Kim, Shouqi Xie〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present study was conducted to evaluate dietary inosine 5′-monophosphate (5′-IMP) on growth, immune genes expression and disease resistance against 〈em〉Aeromonas hydrophila〈/em〉 in juvenile gibel carp (〈em〉Carassius auratus gibelio〈/em〉 var. CAS Ⅲ) (initial body weight: 7.48 g). Six diets were formulated containing exogenous 5′-IMP at three gradient levels (0, 0.1% and 0.2%) in the high dietary fishmeal group (15% fishmeal: D1, D2, D3) and in the high dietary soybean meal group (33% soybean meal: D4, D5, D6). Each diet was randomly allotted to triplicate tanks in a recirculating system. After the feeding trial, fish were exposed to 〈em〉Aeromonas hydrophila〈/em〉 challenge. Hematological and immunological responses were analyzed before and after challenge. The results indicated that feeding rate in all 5′-IMP supplemented treatments (D2, D3, D5 and D6) and daily growth coefficient in D5 and D6 were reduced compared with those of respective control treatments (D1 and D4) without 5′-IMP addition (〈em〉P〈/em〉 〈 0.05). The cumulative survival rates were numerically improved by dietary 5′-IMP supplementation (〈em〉P〈/em〉 〉 0.05). Compared with the respective control treatment, in the high fishmeal group, plasma SOD and MPO were significantly elevated in D3 at the end of feeding trial (〈em〉P〈/em〉 〈 0.05), plasma SOD and lysozyme were significantly increased in D3 after bacterial challenge (〈em〉P〈/em〉 〈 0.05); in high soybean meal group, plasma lysozyme activity was significantly elevated in D5 post bacterial challenge (〈em〉P〈/em〉 〈 0.05). Most of the expression of immune related genes (intelectin, major histocompatibility complex class II β (MHC II β), Complement 3 (C3), Complement component C7-1 (ccC7), lysozyme C, Interleukin 1β (IL-1β), Tumor necrosis factor α1 (TNF-α1), Transforming growth factor-beta (TGF-β) and Interleukin 8 (IL-8)) in spleen, kidney and liver of the fish were significantly affected by supplementation of 5′-IMP at the end of feeding trial and post bacterial challenge. Additionally, adding 5′-IMP in high soybean meal diets exerted further effects of promoting immunity than counterparts in high fishmeal diets. Considering enhanced disease resistance, the immunopotentiation of 5′-IMP was manifested when the addition level was 0.1% in high soybean meal diets and 0.2% in high fishmeal diets.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Kai-Zhuo Wang, Lin Feng, Wei-Dan Jiang, Pei Wu, Yang Liu, Jun Jiang, Sheng-Yao Kuang, Ling Tang, Yong-An Zhang, Xiao-Qiu Zhou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present study explored the effects of dietary gossypol on the gut health of on-growing grass carp. The fish were fed six diets containing different levels of free gossypol (0, 121.38, 243.94, 363.89, 759.93 and 1162.06 mg/kg diet) from gossypol-acetic acid for 60 days and then challenged with 〈em〉Aeromonas hydrophila〈/em〉 for 14 days. The results showed that dietary gossypol (1) could aggravate enteritis and damage the structure of intestinal epithelial cells, (2) decreased the lysozyme (LZ) and Acid phosphatase (ACP) activities, complement 3 (C3), C4 and immunoglobulin M (IgM) contents, and it down-regulated the Hepcidin (rather than distal intestine (DI)), immunoglobulin Z (IgZ), liver-expressed antimicrobial peptide (LEAP)-2B, Mucin2 and β-defensin-1 mRNA levels in the proximal intestine (PI), mid intestine (MI) and DI, (3) up-regulated intestinal pro-inflammatory cytokines tumor necrosis factor α (TNF-α), interferon γ2 (IFN-γ2), interleukin 1β (IL-1β), IL-6 (only in PI), IL-8 and IL-12p35 mRNA levels partly related to nuclear factor kappa B (NF-κB) signalling, and (4) down-regulated the mRNA levels of anti-inflammatory cytokines such as transforming growth factor (TGF)-β1, TGF-β2, interleukin 4/13A (IL-4/13A) (except IL-4/13B), IL-10 and IL-11 partly relating to target of rapamycin (TOR) signalling in the intestines of on-growing grass carp. Moreover, the dietary gossypol had no impact on the LEAP-2A, IL-12P40, IL-17D, IL-10, NF-κBp52, IKKα and eIF4E-binding proteins 2 (4E-BP2) mRNA levels in the intestines. Finally, based on the intestinal histopathological results, enteritis morbidity, LZ activity and IgM content, the safe dose of gossypol in the diets for on-growing grass carp should be less than 103.42 mg/kg diet.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Zhenzhen Zhou, Ke Wei, Jianshe Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, we identified and characterized a tripartite motif containing 25 (TRIM25) gene homologue, LcTRIM25, from large yellow croaker (〈em〉Larimichthys crocea〈/em〉). Two isoforms of LcTRIM25, which were generated via alternative splicing, were identified via a molecular analysis of cDNA clones. The long isoform of LcTRIM25 (termed as LcTRIM25-L) contained the full open reading frame of the gene, encoded a protein of 698 amino acid residues, and possessed 11 exons. The short isoform of LcTRIM25 (termed as LcTRIM25-S) contained 9 exons and encoded a protein of 665 amino acid residues. The two LcTRIM25 isoforms contained a conserved Really Interesting New Gene (RING) domain, a B-box2 domain, a Coiled-coil domain (CCD), and variable C-terminal PRY/SPRY domains. Phylogenetic analysis showed that the two LcTRIM25 isoforms of the large yellow croaker was clustered together with their counterparts from other teleost fish. The Real-time PCR analysis showed that the LcTRIM25-L and LcTRIM25-S isoforms were both ubiquitously expressed in nine examined tissues in the large yellow croaker, with predominant expressions in the liver. The expression levels of the two isoforms of LcTRIM25 were rapidly and significantly upregulated 〈em〉in vivo〈/em〉 after poly (I:C) stimulation in peripheral blood, head kidney, spleen and liver. Moreover, LcTRIM25-L and LcTRIM25-S showed differential expression post poly(I:C) stimulation. LcTRIM25 may have a dual role in innate immunity via alternative gene splicing. These results indicated that LcTRIM25 is likely to be involved in antiviral immune responses.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Guanghua Xiong, Lufang Zou, Yunyun Deng, Yunlong Meng, Xinjun Liao, Huiqiang Lu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Clethodim is one of the most widely used herbicides in agriculture, but its potential negative effects on aquatic organisms are still poorly understood. This study examined the effects of clethodim on zebrafish at aspects of early stage embryonic development, immune toxicity, cell apoptosis and locomotor behavior. Firstly, clethodim exposure markedly decreased the survival rate, body length, and heart rate and resulted in a series of morphological abnormalities, primarily spinal deformities (SD) and yolk sac edema, in zebrafish larvae. Secondly, the number of immune cells was substantially reduced but the levels of apoptosis and oxidative stress were significantly increased in a dose-dependent manner upon clethodim exposure. Thirdly, we evaluated the expression of some key genes in TLR signaling including 〈em〉TLR4〈/em〉, 〈em〉MyD88〈/em〉, and 〈em〉NF-κB p65〈/em〉 and they were all up-regulated by exposure to 300 μg/L clethodim. Meanwhile, some proinflammatory cytokines such as 〈em〉TNF-α〈/em〉, 〈em〉IL-1β〈/em〉, 〈em〉IL8,〈/em〉 and 〈em〉IFN-γ〈/em〉 were also activated in both the mock and the 〈em〉TLR4-KD〈/em〉 conditions. Moreover, the locomotor behaviors and the enzymatic activities of AChE were obviously inhibited but the levels of acetylated histone H3 were greatly increased by clethodim exposure. In addition, incubation of zebrafish larvae with acetylcholine receptor (AChR) agonist carbachol can partially rescue the clethodim-modulated locomotor behavior. Taken together, our results suggest that clethodim has the potential to induce developmental immunotoxicity and cause behavioral alterations in zebrafish larvae. The information presented in this study will help to elucidate the molecular mechanisms underlying clethodim exposure in aquatic ecosystems.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Zan Pang, Yao Zhang, Liqin Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Interferon-γ-inducible lysosomal thiol reductase (GILT) is a pivotal enzyme involved in the histocompatibility complex (MHC) class II-restricted antigen processing whereby it catalyzes the disulfide bond reduction in the endocytic pathway. Here, a novel GILT homologue termed as 〈em〉SjGILT〈/em〉 firstly identified from common Chinese cuttlefish 〈em〉Sepiella japonica.〈/em〉 SjGILT shared domain topology containing a signal peptide, a signature sequence CQHGX〈sub〉2〈/sub〉ECX〈sub〉2〈/sub〉NX〈sub〉4〈/sub〉C, an activate-site CXXC motif, two potential N-glycosylation sites and six conserved cysteins with its counterparts in other animals. 〈em〉SjGILT〈/em〉 transcripts were constitutively expressed in all examined tissues in 〈em〉S. japonica〈/em〉, with the higher expression levels in immune-related tissues such as pancreas, intestines, liver and gills. Upon lipopolysaccharide (LPS) challenge, 〈em〉SjGILT〈/em〉 transcripts were significantly induced in liver and gill tissues, and 〈em〉SjGILT〈/em〉 protein transferred to late endosomes and lysosomes in HeLa cells. Further study showed that recombinant 〈em〉SjGILT〈/em〉 had obvious thiol reductase activity demonstrated by reducing the interchain disulfide bonds of IgG under acidic conditions. Taken together, these results suggested that 〈em〉SjGILT〈/em〉 may be involved in the immune response to bacteria challenge, and then might play an important role in the processing of MHC class II-restricted antigens in 〈em〉S. japonica〈/em〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Yao-Wu Fu, Cheng-Ke Zhu, Qi-Zhong Zhang, Ting-Long Hou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The complement system plays an important role in host defense against invading microorganisms. Complement component C9 is the last component that is involved in the formation of the membrane attack complex (MAC) on the surface of target cells. In the present study, the full length C9 cDNA sequence of 1984 bp with an open reading frame (ORF) of 1809 bp was cloned from southern catfish (〈em〉Silurus meridionalis〈/em〉). The deduced amino acid sequence showed similarity with other teleost fish. The mRNA expression of C9 was detected in the liver, spleen, stomach, intestine, and head kidney, with highest levels detected in the liver. The mRNA of C9 was first detected in the yolk syncytial layer at 34 h post fertilization (hpf) with whole mount 〈em〉in situ〈/em〉 hybridization, followed by the liver at 36 h post hatching (hph). The mRNA expression of C9 was upregulated significantly in the liver, spleen, and intestine following the injection with 〈em〉Aeromonas hydrophila〈/em〉, suggesting that C9 played an important role in defense against invading pathogens in southern catfish. Therefore, these results provide important information to understand the functions of C9 during fish early development in fish.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Sarah J. Poynter, Eric M. Leis, Stephanie J. DeWitte-Orr〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The farming of baitfish, fish used by anglers to catch predatory species, is of economic and ecological importance in North America. Baitfish, including the fathead minnow (〈em〉Pimephales promelas),〈/em〉 are susceptible to infection from aquatic viruses, such as viral hemorrhagic septicemia virus (VHSV). VHSV infections can cause mass mortality events and have the potential to be spread to novel water bodies through baitfish as a vector. In this study, a novel skin cell line derived from fathead minnow (FHMskin) is described and its use as a tool to study innate antiviral immune responses and possible therapies is introduced. FHMskin grows optimally in 10% fetal bovine serum and at warmer temperatures, 25–30 °C. FHMskin is susceptible and permissive to VHSV-IVb infection, producing high viral titres of 7.35 × 10〈sup〉7〈/sup〉 TCID〈sub〉50〈/sub〉/mL after only 2 days. FHMskin cells do not experience significant dsRNA-induced death after treatment with 50–500 ng/mL of 〈em〉in vitro〈/em〉 transcribed dsRNA for 48 h and respond to dsRNA treatment by expressing high levels of three innate immune genes, viperin, ISG15, and Mx1. Pretreatment with dsRNA for 24 h significantly protected cells from VHSV-induced cell death, 500 ng/mL of dsRNA reduced cell death from 70% to less than 15% at a multiplicity of infection of 0.1. Thus, the novel cell line, FHMskin, represents a new method for producing high tires of VHSV-IVb in culture, and for studying dsRNA-induced innate antiviral responses, with future applications in dsRNA-based antiviral therapeutics.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Ning-ning Guo, Xue-jun Sun, Ya-kai Xie, Gui-wen Yang, Cui-jie Kang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As an important disulfide reductase of the intracellular antioxidant system, Thioredoxin (Trx) plays an important role in maintaining oxidative stress balance and protecting cells from oxidative damage. In recent years, there is increasing evidence that Trx is a key molecule in the pathogenesis of various diseases and a potential therapeutic target for major diseases including lung, colon, cervical, gastric and pancreatic cancer. However, few knowledge is known about the function of Trx in virus infection. In this study, we reported the cloning and functional investigation of a Trx homologue gene, named 〈em〉MjTrx〈/em〉, in shrimp 〈em〉Marsupenaeus japonicus〈/em〉 suffered white spot syndrome virus (WSSV) infection. 〈em〉Mj〈/em〉Trx is a 105-amino acid polypeptide with a conservative Cys-Gly-Pro-Cys motif in the catalytic center. Phylogenetic trees analysis showed that 〈em〉Mj〈/em〉Trx has a higher relationship with Trx from other invertebrate and clustered with Trx1 from arthropod. 〈em〉MjTrx〈/em〉 transcripts is abundant in the gill and intestine tissues and can be detected in the hemocytes, heart, stomach, and hepatopancreas tissues. The transcription levels of 〈em〉MjTrx〈/em〉 in hemocytes, gills and intestine tissues of shrimp were significantly up-regulated after white spot syndrome virus infection. 〈em〉Mj〈/em〉Trx was recombinant expressed in vitro and exhibited obvious disulfide reductase activity. In addition, overexpression 〈em〉Mj〈/em〉Trx in shrimp resulted in the increase of hydrogen peroxide (H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉) concentration in vivo. All these results strongly suggested that 〈em〉Mj〈/em〉Trx functioned in redox homeostasis regulating and played an important role in shrimp antiviral immunity.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Chi Zhang, Ningqiu Li, Xiaozhe Fu, Qiang Lin, Li Lin, Jiagang Tu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉MicroRNAs (miRNAs) are small noncoding RNAs that have been reported to play important roles in virus replication. Snakehead vesiculovirus (SHVV) is a new rhabdovirus isolated from diseased hybrid snakehead and has caused heavy economical losses in cultured snakehead fish in China. Our previous study has revealed that miR-214 inhibited SHVV replication, but the underline mechanism was not completely understood. In this study, glycogen synthase (GS) gene was identified as a target gene of miR-214. Overexpression of miR-214 reduced cellular GS gene expression. Knockdown of GS by siRNA, similar to the overexpression of miR-214, inhibited SHVV replication. Moreover, we found that siGS-mediated inhibition of SHVV replication could be restored by reducing cellular miR-214 level via using miR-214 inhibitor, indicating that miR-214 inhibited SHVV replication at least partially via targeting GS. This study provided information for understanding the molecular mechanism of SHVV pathogenicity and a potential antiviral strategy against SHVV infection.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Hidehiro Kondo, Seangmin Chung, Eriko Hirosawa, Ikuo Hirono〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We evaluated the effects of Freund's adjuvants (FCA/FIA) on protection and immune response of Japanese flounder 〈em〉Paralichthys olivaceus〈/em〉 immunized by the formalin-killed cell (FKC) of 〈em〉Edwardsiella tarda〈/em〉. Combination of FKC and FCA/FIA did not confer protection against the challenge, while they significantly induced higher antibody titers than that of FKC only. The suppression of FKC-dependent induction of interferon γ (IFNγ) mRNA levels by FCA/FIA was observed by gene expression profiling. Similarly, interleukin (IL)-12 p35 mRNA levels were not detected after FKC+FCA or +FIA. These results suggest that the mineral oil in Freund's adjuvants might suppress the signaling pathway(s) that induce IFNγ and IL-12 gene expression.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 83〈/p〉 〈p〉Author(s): Shengzhen Jin, Xin Zhao, Hongquan Wang, Jianming Su, Jing'an Wang, Chunhua Ding, Yaoguo Li, Tiaoyi Xiao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The barbel chub (〈em〉Squaliobarbus curriculus〈/em〉) is a kind of small size commercial fish species that is widely spread in Asia and has shown significant resistance to disease. In this study, the full-length cDNA sequences of 〈em〉Toll-like receptor〈/em〉 (〈em〉TLR〈/em〉) 〈em〉7〈/em〉 and 〈em〉8〈/em〉 from 〈em〉S. curriculus〈/em〉, designated as 〈em〉ScTLR7〈/em〉 and 〈em〉ScTLR8〈/em〉, were cloned, and their differences in the structure and the responses to the grass carp (GCRV) infection and lipopolysaccharide stimulation were investigated. The full-length 3715 base pair (bp) cDNA of 〈em〉ScTLR7〈/em〉 contained a complete open reading frame of 3162 bp and encoded a putative polypeptide of 1053 amino acid residues. The full-length 4624 base pair (bp) cDNA of 〈em〉ScTLR8〈/em〉 contained a complete open reading frame of 3072 bp and encoded a putative polypeptide of 1023 amino acid residues. 〈em〉ScTLR7〈/em〉 and 〈em〉ScTLR8〈/em〉 consisted of N-terminal signal peptide, leucine-rich repeats (LRRs), and Toll/IL-1 Receptors domain. LRR motifs of 〈em〉ScTLR7〈/em〉 and 〈em〉ScTLR8〈/em〉 bend into horseshoe-like solenoid structure, while the number of LRRs between the two genes is different. Phylogenetic analysis showed that both the 〈em〉ScTLR7〈/em〉 and 〈em〉ScTLR8〈/em〉 were closely clustered with 〈em〉Ctenopharyngodon idellus〈/em〉 and 〈em〉Megalobrama amblycephala〈/em〉. Quantitative real-time polymerase chain reaction analysis showed that the expression levels of 〈em〉ScTLR7〈/em〉 in 〈em〉S. curriculus〈/em〉 were most abundant in the brain followed by the spleen and heart, and the lowest in the intestine. The highest expression level of 〈em〉ScTLR8〈/em〉 was observed in spleen and the lowest in the liver. After LPS stimulation, the relative expression levels of both 〈em〉ScTLR7〈/em〉 and 〈em〉ScTLR8〈/em〉 exhibited an overall trend of up-regulation. The expression levels of 〈em〉type I-IFN〈/em〉 showed an overall trend of down-regulation at time points of 12, 24, 72 and 168 h compared to that of 6 h after LPS stimulation. Compared to 6 h post GCRV infection, the transcription level of 〈em〉ScTLR7〈/em〉 was up-regulated from 12 to 168 h, and transcription levels of 〈em〉ScTLR8〈/em〉, 〈em〉MyD88〈/em〉, and 〈em〉type I-IFN〈/em〉 were firstly up-regulated from 12 to 72 h, and then down-regulated from 72 to 168 h. Correlation analysis showed that expression level of 〈em〉ScTLR7〈/em〉 in the spleen was significantly positively correlated with that of 〈em〉MyD88〈/em〉 (Pearson correlation coefficient: 0.909, 〈em〉P〈/em〉: 0.033), and a significantly positive correlation was also observed between expression levels of 〈em〉MyD88〈/em〉 and 〈em〉type I IFN〈/em〉 (Pearson correlation coefficient: 0.962, 〈em〉P〈/em〉: 0.009), after GCRV stimulation. These results indicate that 〈em〉ScTLR7〈/em〉 and 〈em〉ScTLR8〈/em〉 may play important roles in the responses to the grass carp (GCRV) infection and lipopolysaccharide stimulation and trigger different downstream immune signal pathways.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Liqing Zhou, Dan Zhao, Biao Wu, Xiujun Sun, Zhihong Liu, Feng Zhao, Zhenming Lv, Aiguo Yang, Qing Zhao, Gaowei Zhang, Chunyan Ma〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉〈em〉Scapharca broughtonii〈/em〉 is one of the most important Arcidae aquaculture species in the Asia-Pacific region. We aimed to investigate the immune responses of hemocytes from ark shell 〈em〉S. broughtonii〈/em〉 hemolymph against pathogens. Hemocyte ultrastructure and immunological activity in response to 〈em〉Vibrio anguillarum〈/em〉 challenge were observed by scanning and transmission electron microscopy. Before ultrastructure observation, we used the API ZYM semi-quantitative kit to evaluate the levels of hydrolytic enzymes in the plasma and hemocytes following 〈em〉V. anguillarum〈/em〉 infection. An enzyme-linked immunosorbent assay kit was used to investigate the variation in the lysozyme activity and hemocytes following bacterial infection. The results showed that hemocytes were the main defense cells against bacterial infection, whereas plasma played a role in the transport and support of hemocytes. It was presumed that an important function of lysozymes and hydrolytic enzymes in lysosomes was for bacterial digestion. Three major types of hemocytes were observed, namely, red blood cells (RBCs), white blood cells (WBCs), and thrombocytes (TCs). Scanning electron microscopy showed that the normal RBCs appeared pie-shaped with 10 μm diameter and 4 μm central thickness, whereas WBCs were spherical in shape with varying sizes, 4–8 μm diameter, and included small lymphocytes. TCs were long, spindle-shaped, and 12–20 μm in length. The cell membrane surface was smooth and even for all cells before pathogen challenge. Under transmission electron microscopy, RBCs displayed a limited ability to devour and digest bacteria adherent to the cell surface following infection. Many hemoglobin particles were observed in the RBC cytoplasm. WBCs were very active against bacterial invasion and showed a strong ability to digest and decompose infected and wrapped 〈em〉V. anguillarum〈/em〉 through phagocytosis and lysosome fusion. Digestive vacuoles rapidly became transparent and were thought to contain increasing quantities of pathogen-induced lysozymes. WBCs that devoured pathogenic bacteria were prone to deformation as well as adhesion to each other. TCs were rich in endoplasmic reticulum (ER) content in their cytoplasm and were widely connected in a net-shaped structure. Mitochondria in TCs formed clusters upon invasion of 〈em〉V. anguillarum〈/em〉 in the hemolymph. TCs disintegrated to release the ER into the plasma to form a mesh that facilitated clotting. The ability of circulating hemocytes to quickly modify their morphologies and stainability suggests that 〈em〉S. broughtonii〈/em〉 is endowed with highly dynamic hemocyte populations capable of coping with environmental changes and rapidly growing pathogens.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 83〈/p〉 〈p〉Author(s): Min Sun Kim, Min Jun Shin, Ki Hong Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Viral hemorrhagic septicemia virus (VHSV) has been a notorious pathogen in freshwater and marine fish. Due to the lack of effective treatment measures against VHSV disease, the development of prophylactic vaccines has been required, and methods that can produce high-titered viruses would be advantageous in producing cost-effective vaccines. Type I interferon (IFN) responses are the key elements of vertebrates' antiviral activities, and IFN-stimulated gene factor 3 (ISGF3) complex formed through type I IFNs up-regulates the expression of IFN-stimulated genes (ISGs). IFN regulatory factor 9 (IRF9) is a key component of ISGF3, so the inhibition of IRF9 would compromise host's type I IFN responses, which would weaken host antiviral activity. In this study, to increase the replication of VHSV, we generated IRF9 knockout Epithelioma papulosum cyprini (EPC) cells using a CRISPR/Cas9 vector that contains an EPC cell's U6 promoter-driven guide RNA cassette (targeting IRF9 gene) and a Cas9 expressing cassette. In the clones of IRF9 knockout EPC cells, there were no increase in ISG15 gene by poly I:C, and in Mx1 gene by both poly I:C and VHSV. Interestingly, although the increased folds were conspicuously lower than control EPC cells, the expression of ISG 15 gene in all the IRF9 knockout clones was significantly increased by VHSV infection. Control EPC cells pre-treated with poly I:C did not show any CPE when infected with VHSV, however, IRF9 knockout EPC cells showed CPE by VHSV infection in spite of being pretreated with poly I:C. The replication of VHSV in IRF9 knockout EPC cells was significantly faster and higher than that in control EPC cells indicating that the IRF9 knockout-mediated decrease of type I IFN responses allowed VHSV to replicate efficiently. Considering an economical aspect for the production of fish vaccines, the present IRF9 knockout EPC cells can be used to get higher-titered VHSV.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Hongliang Zuo, Jia Yuan, Linwei Yang, Zhiwei Liang, Shaoping Weng, Jianguo He, Xiaopeng Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The thioredoxin (Trx) system plays essential roles in maintenance and regulation of the redox state of cysteine residues in cellular proteins. The Trx-interacting protein (TXNIP) is a TRX inhibitory protein that works as a negative regulator in the TRX system. The function of TXNIP in invertebrates, in particular in immunity, remains unclear to date. In the current study, a novel TXNIP from Pacific white shrimp 〈em〉Litopenaeus vannamei〈/em〉 was identified and characterized and its roles in immune responses was investigated. TXNIP could interact with Trx and inhibit its redox regulatory activity, suggesting that TXNIP was involved in regulation of the cellular redox state in shrimp. The expression of TXNIP was high in the stomach, gill, scape, eyestalk, epithelium, pyloric and muscle and low in the hepatopancreas, intestine, nerve, hemocytes and heart. Stimulations with pathogens white spot syndrome virus (WSSV) and 〈em〉Vibrio parahaemolyticus〈/em〉 and immune stimulants poly (I:C) and LPS could significantly increase the expression of TXNIP 〈em〉in vivo〈/em〉. Silencing of TXNIP using RNAi strategy significantly facilitated the infection of 〈em〉V. parahaemolyticus〈/em〉 but inhibited the infection of WSSV in shrimp. These indicated that TXNIP could be positively involved in antibacterial responses but negatively involved in antiviral responses in shrimp. Moreover, knockdown of TXNIP 〈em〉in vivo〈/em〉 exerted opposite effects on expression of antimicrobial peptides anti-lipopolysaccharide factors and penaeidins and enhanced the phagocytic activity of hemocytes against bacteria. These suggested that TXNIP could play a complex role in regulation of humoral and cellular immune responses in shrimp.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 83〈/p〉 〈p〉Author(s): Hang Su, Jianguo Su〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the past decades, global freshwater fish production has been rapidly growing, while cyprinid takes the largest portion. Along with the rapid rise of novel forms of intensive aquaculture, increased global aquatic animal movement and various anthropogenic stress to aquatic ecosystems during the past century, freshwater fish farming industry encounter the emergence and breakout of many diseases, especially viral diseases. Because of the ability to safely and effectively prevent aquaculture diseases, vaccines have become the mainstream technology for prevention and control of aquatic diseases in the world. In this review, authors summarized six major cyprinid viral diseases, including koi herpesvirus disease (KHVD), spring viraemia of carp (SVC), grass carp hemorrhagic disease (GCHD), koi sleepy disease (KSD), carp pox disease (CPD) and herpesviral haematopoietic necrosis (HPHN). The present review described the characteristics of these diseases from epidemiology, pathology, etiology and diagnostics. Furthermore, the development of specific vaccines respective to these diseases is stated according to preparation methods and immunization approaches. It is hoped that the review could contribute to aquaculture in prevention and controlling of cyprinid viral diseases, and serve the healthy and sustainable development of aquaculture industry.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Zhao Lv, Xiaorui Song, Jiachao Xu, Zhihao Jia, Bin Yang, Yunke Jia, Limei Qiu, Lingling Wang, Linsheng Song〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The mitochondrial pathway of apoptosis is well studied as the major mechanism of physiological cell death in vertebrates. In the present study, a second mitochondria-derived activator of caspases (Smac)/direct inhibitor of apoptosis-binding protein (IAP) with low pI protein (DIABLO) (designated as 〈em〉Cg〈/em〉Smac) was identified from oyster 〈em〉Crassostrea gigas〈/em〉. The open reading frame of 〈em〉Cg〈/em〉Smac was of 966 bp nucleotides encoding a predicted polypeptide of 321 amino acids with a conserved Smac/DIABLO domain containing a potential IAP-binding motif of VMPV. 〈em〉Cg〈/em〉Smac proteins were distributed in hemocytes and co-localized with mitochondria. Western blotting analysis revealed that 〈em〉Cg〈/em〉Smac proteins mainly existed in the dimer form in hemocytes, and the monomeric precursors and mature monomers were also detected. After lipopolysaccharide (LPS) stimulation, the mRNA expression of 〈em〉Cg〈/em〉Smac in hemocytes was significantly up-regulated and peaked at 6 h (12.26-fold, 〈em〉p〈/em〉 〈 0.05), and the protein level of its dimers was significantly up-regulated at 6 h, 12 h, 24 h, and 48 h, while that of 〈em〉Cg〈/em〉Smac monomers was up-regulated at 6 h, 12 h and down-regulated at 24 h, 48 h. The decrease of mitochondrial membrane potential indicated that the occurrence of early stage of apoptosis in primary cultured hemocytes was induced by LPS, and RNA interference (RNAi) of 〈em〉Cg〈/em〉Smac could not rescue this decrease. The caspase-3 activity in primary cultured hemocytes was significantly suppressed after RNAi of 〈em〉Cg〈/em〉Smac. Correspondingly, the total apoptotic rate of primary cultured hemocytes was also significantly suppressed in ds〈em〉Cg〈/em〉Smac + LPS group (31.57%) compared to dsEGFP + LPS group (40.27%, 〈em〉p〈/em〉 〈 0.05), which in turn demonstrated the conserved pro-apoptotic function of 〈em〉Cg〈/em〉Smac. Furthermore, the early apoptotic rate (10.4% vs. 8.5%, 〈em〉p〈/em〉 〈 0.05) was significantly higher in dsCgSmac + LPS group than that of dsEGFP + LPS group, while the necrosis (7.7% vs. 10.0%, 〈em〉p〈/em〉 〈 0.05) and late apoptotic rates (13.4% vs. 21.9%, 〈em〉p〈/em〉 〈 0.05) were lower in ds〈em〉Cg〈/em〉Smac + LPS group than those of dsEGFP + LPS group. Collectively, 〈em〉Cg〈/em〉Smac could activate mitochondrial apoptosis pathway by promoting caspase-3 activity in oyster hemocytes against exogenous LPS invasion. These results provided new insights on oyster apoptosis and the immune defense mechanisms in invertebrates.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Patrycja Schulz, Stanisław Robak, Jarosław Dastych, Andrzej Krzysztof Siwicki〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Inland fishery belongs to those branches of animal production that use very large amounts of chemotherapeutics, in particular antibiotics. The accumulation of chemotherapeutic agents in bottom sediments is a direct threat to the aquatic environment and directly affects the condition and health of the fish. Finding a preparation that could be used both prophylactically to increase the resistance of fish and therapeutically in case of infection with pathogenic bacteria, without side effects for fish and aquatic environment could be a great solution to this problem. Our aim was to determine influence of BAFADOR〈sup〉®〈/sup〉 the new bacteriophage-based preparation on European eel immunity and survival after experimental challenge. Application of BAFADOR〈sup〉®〈/sup〉 increased total protein level, immunoglobulin level, lysozyme activity and ceruloplasmin level in European eel serum. Potential killing activity and metabolic activity of spleen phagocytes as well as pronephros lymphocyte proliferation of was higher compared to control. The preparation also reduced mortality after experimental infections with the pathogenic bacteria 〈em〉Aeromonas hydrophila〈/em〉 and 〈em〉Pseudomonas fluorescens〈/em〉. Our results showed that preparation BAFADOR〈sup〉®〈/sup〉 is well tolerated by the fish organism causing stimulation of cellular and humoral immunity parameters and reduces the mortality of the European eel after experimental challenge.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 83〈/p〉 〈p〉Author(s): Lingjie Luo, Juan Lu, Qin Wang, Shangwu Chen, Anlong Xu, Shaochun Yuan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Autophagy is a homeostatic process which degrades cytoplasmic constituents to maintain the balance of organs when they were challenged with nutrient stress. It also participates in cancer, neurodegenerative disorders, aging and innate immune defense. In order to reveal how autophagy participates in innate immune response when invertebrates evolved into vertebrates. Firstly, we performed a systematic analysis of 〈em〉Atg〈/em〉 genes and found that they are highly conserved among lancelet, lamprey and zebrafish. Then, we observed autophagosomes upon starvation by TEM in lancelet, lamprey and zebrafish and found that the morphology of autophagosome is similar to that was observed in yeast and mammals. In addition, rapamycin can induce autophagy in lamprey leukocytes and the deficiency of human Beclin1 protein can be rescued by lancelet and lamprey Beclin1 proteins. When lamprey leukocytes were treated with polyI:C and LPS, autophagy was induced. Moreover, when lamprey leukocytes were challenged with live 〈em〉E. coli〈/em〉, phagocytosis along with autophagy was triggered to degrade pathogenic bacteria. In all, our study here indicated that autophagy is highly conserved during evolution and plays a key role in innate defense when invertebrates evolved into vertebrates.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Wenting Xu, Chenglong Jiao, Pengcheng Bao, Qin Liu, Pengbo Wang, Ruilin Zhang, Xiaohong Liu, Yuanxing Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Turbot (〈em〉Scophthalmus maximus〈/em〉 L.) is a commercially important fish species in China. Despite of its great economic potential, fish farms often suffer severe economic losses due to certain fish diseases. Vaccination has become a common strategy to prevent diseases caused by pathogens in aquaculture industry. However, no inactivated vaccine against 〈em〉Vibrio harveyi〈/em〉 of turbot has been reported so far. In this study, we developed an inactivated vaccine using formalin-killed cells of 〈em〉V. harveyi〈/em〉 and the efficacy of a commercial adjuvant Montanide™ ISA 763 A VG on the inactivated vaccine was evaluated. We found that with an optimum vaccine dosage at 1.0 × 10〈sup〉8〈/sup〉 CFU/fish, a high relative percent survival (RPS) more than 75% was observed at 4 weeks post vaccination (w.p.v.). Moreover, enhanced antibody titer, lysozyme activity, total serum protein and antibacterial property in sera of vaccinated fish were observed at 4, 8, 12 and 16 w.p.v. In conclusion, we developed an efficient inactivated vaccine against 〈em〉V. harveyi〈/em〉 in turbot, which not only induced humoral immunity, but also enhanced initial innate immune response for long-term protection.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 83〈/p〉 〈p〉Author(s): M.J. Peixoto, A. Domingues, S. Batista, J.F.M. Gonçalves, A.M. Gomes, S. Cunha, L.M.P. Valente, B. Costas, R.O.A. Ozório〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉This study aimed to evaluate the protective effects of four autochthonous bacteria isolated from juvenile sole (〈em〉Solea senegalensis〈/em〉) intestine as dietary probiotic supplement against bacterial pathogen infection and handling/transport stressors. Growth performance and immune responses were evaluated after 85 days of feeding trial. Sole (IBW = 16.07 ± 0.11 g) were fed six experimental diets, a control diet (CTRL, without the dietary probiotic supplementation), and five diets supplemented with probiotic bacteria: PB1 (〈em〉Shewanella hafniensis〈/em〉), PB2 (〈em〉Enterococcus raffinosus〈/em〉), PB3 (〈em〉Shewanella hafniensis〈/em〉 + 〈em〉Arthrobacter soli〈/em〉), PB4 (〈em〉Pseudomonas protegens〈/em〉 + 〈em〉Arthrobacter soli〈/em〉) and PB5 (〈em〉Shewanella hafniensis〈/em〉 + 〈em〉Arthrobacter soli〈/em〉 + 〈em〉Enterococcus raffinosus〈/em〉). All bacteria were selected based on their 〈em〉in vitro〈/em〉 antimicrobial activity. After the growth trial, fish were submitted to a stress factor (transport) and then each dietary group was divided in two additional groups: non-infected (placebo) and infected with 〈em〉Photobacterium damselae〈/em〉 subsp. 〈em〉piscicida〈/em〉. Immune and antioxidant responses were evaluated at day 10 post-infection. In infection trial A, fish were infected on the same day of transport, whereas in trial B fish were infected after a 7-day recovery from the transport stress. At the end of the feeding trial, fish fed with PB2 and PB4 showed lower final body weight when compared with the other dietary groups. Respiratory burst activity and nitric oxide production were not affected by probiotic supplementation. Fish fed with PB5 presented lower peroxidase activity compared to CTRL. Lysozyme and alternative complement pathway activity (ACH50) showed no significant differences between treatments. The innate immune responses were significantly affected after handling stress and bacterial infection. In trial A, the ACH50 levels of infected fish were significantly lower than the placebo groups. On the other hand, in trial B fish infected with 〈em〉Pdp〈/em〉 demonstrated higher ACH50 levels when compared to placebos. Peroxidase levels were strongly modulated by bacterial infection and handling stress. In trials A and B, infection had a clear downgrade effect in peroxidase levels. Lipid peroxidation, catalase, glutathione S-transferase and glutathione reductase were altered by both bacterial infection and transport.〈/p〉 〈p〉Overall, dietary probiotic supplementation did not influence growth performance of sole. The immune and oxidative defenses of sole responded differently to infection depending on the probiotic and the synergy between pathogen infection and transport.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 83〈/p〉 〈p〉Author(s): Di Huang, Xue-Li Qiao, Qing-jian Liang, Wei Wei, Jing-Rong Kong, Chang-sheng Zhao Huan Kang, Yuan Liu, Wei-Na Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nucleotide excision repair (NER) removes many different types of DNA lesions, and NER related host factors are reported to aid recovery steps during viral integration. Here, we report the identification and characterization of a DNA repair gene Rad23 from 〈em〉Litopenaeus vannamei〈/em〉 and explore its role in innate immunity of crustaceans. 〈em〉Lv〈/em〉Rad23 contains a1149 bp open reading frame (ORF) which encodes a 382 amino acids protein with predicted theoretical isoelectric point of 4.21. 〈em〉Lv〈/em〉Rad23 was ubiquitously expressed in the muscle, eyestalk, gill, stomach, heart, legs, intestine, and hepatopancreas in order from high to low and 〈em〉Lv〈/em〉Rad23 protein was showed to be located in the cytoplasm of Drosophila S2 cells. The homology analysis showed that it has a high sequence homology with Rad23 protein from 〈em〉Marsupenaeus japonicus〈/em〉. 〈em〉Vibrio alginolyticus〈/em〉 challenge induced a remarkable up-regulation of 〈em〉Lv〈/em〉Rad23 mRNA in hepatopancreas. Knocking down 〈em〉Lv〈/em〉Rad23can interfere the NER pathway by down regulating the expression of replication protein A (RPA) and proliferating cell nuclear antigen (PCNA). However it didn't cause any significant difference on total hemocyte count (THC) between 〈em〉Lv〈/em〉Rad23-silenced and non-silenced group.〈em〉Lv〈/em〉Rad23-silenced then challenge with 〈em〉V. alginolyticus〈/em〉 inducing high level of reactive oxygen species (ROS) and DNA damage in hemolymph. As well as decreased THC, which seriously diminished the innate immune system of 〈em〉L. vannamei〈/em〉. Meanwhile, the NER pathway was reactived by enhancing the expression of 〈em〉Lv〈/em〉Rad23 and promoting the production of 〈em〉Lv〈/em〉PCNA to resist apoptosis and maintain proliferation of hemolymph cells in the later stage. Our results suggest that 〈em〉Lv〈/em〉Rad23 plays a vital role in shrimp specific immune response to 〈em〉V. alginolytcus〈/em〉 through its participation in NER pathway.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 83〈/p〉 〈p〉Author(s): Qi Zheng, Huasong Ji, Shina Wei, Jufen Tang, Yishan Lu, Jia Cai, Jichang Jian, Qiwei Qin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bcl-2 family proteins play essential roles in modulating immune response and controlling cells’ fate. Bcl-xL is one of anti-apoptotic protein in this family. In this study, a new Bcl-xL homolog (EcBcl-xL) was identified and characterized from orange-spotted grouper, 〈em〉Epinephelus coioides〈/em〉. EcBcl-xL encoded a 221 amino acid peptides that shared 86% identity to 〈em〉Larimichthys crocea〈/em〉 Bcl-xL protein, contained four conserved BH domains and one transmembrane region. The predicted three-dimensional structure of EcBcl-xL was similar with 〈em〉Homo sapiens〈/em〉 Bcl-xL. EcBcl-xL widely expressed in all tested tissues with highest expression in head kidney. Its expression level was significantly up-regulated after SGIV infection 〈em〉in vivo〈/em〉. Furthermore, overexpression of EcBcl-xL could inhibit SGIV-induced nonapoptotic cell death and suppressed viral genes transcriptions in GS cells. Our findings suggested that EcBcl-xL might play a role during virus infection through modulating SGIV-induced nonapoptotic cell death.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Zibo Wei, Wanwei Sun, Ngoc Tuan Tran, Yi Gong, Hongyu Ma, Huaiping Zheng, Yueling Zhang, Shengkang Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Serine proteases (SPs) are important in various immune responses, including prophenoloxidase (proPO) activation, antimicrobial peptides (AMPs) synthesis, and hemolymph coagulation in invertebrates. In this study, SP3 and SP5 of mud crab (〈em〉Scylla paramamosain〈/em〉) were studied. SP3 and SP5 were expressed in all examined tissues (mainly in hemocytes), and are associated with the immune responses of mud crab to 〈em〉Vibrio parahemolyticus〈/em〉 and 〈em〉Staphylococcus aureus〈/em〉, as well as interacted with TRAF6, and are involved in the activation of anti-lipopolysaccharide factors (ALFs) probably through the TLR/NF-κB pathway. Depletion of SP3 inhibited the expression of ALF1, ALF2, ALF3, and ALF6, while knockdown of SP5 significantly decreased ALF5, and ALF6. Furthermore, both SP5 and TRAF6 regulated the PO activity in the hemolymph of mud crab. Overexpression assay showed that both SP3 and SP5 could enhance the promoter activities of ALFs in mud crab. Taken together, the results of this study indicate that SP3 and SP5 might play important roles in the immune system of mud crab against pathogen invasion.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 83〈/p〉 〈p〉Author(s): Kexin Duan, Xiaojing Hua, Yuting Wang, Yanxue Wang, Yaping Chen, Wen Shi, Lijie Tang, Yijing Li, Min Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Infectious pancreatic necrosis virus (IPNV) infects wild and cultured salmonid fish causing high mortality with serious economic losses to salmonid aquaculture. Ideally, the method of oral immunization should prevent the infection of rainbow trout juveniles with IPNV. In the present study, genetically engineered 〈em〉Lactobacillus casei〈/em〉 393 pPG-612-VP2/〈em〉L. casei〈/em〉 393 and pPG-612-CK6-VP2/〈em〉L. casei〈/em〉 393 constitutively expressing VP2 protein of IPNV were constructed. The recombinant strains pPG-612-CK6-VP2/〈em〉L. casei〈/em〉 393 and pPG-612-VP2/〈em〉L. casei〈/em〉 393 were orally administrated to juvenile rainbow trouts, and significant titers of IgM and IgT of pPG-612-CK6-VP2/〈em〉L. casei〈/em〉 393 were observed. The results demonstrate that the recombinants could elicit both local mucosal and systemic immune responses. The proliferation of spleen lymphocytes in trouts immunized with pPG-612-CK6-VP2/〈em〉L. casei〈/em〉 393 showed that the recombinant strain could induce a strong cellular immune response. The IL-1β, IL-8, CK6, MHC-II, Mx, β-defensin, and TNF-1α levels in the spleen and gut suggest that the target molecular chemokine has the ability to attract relevant immune cells to participate in the inflammatory response and enhance the function of the innate immune response. Additionally, the pPG-612-CK6-VP2/〈em〉L. casei〈/em〉 393 induced the expression of cytokines, which have the effect of promoting inflammation to drive the differentiation of macrophages and clear target cells. After challenging with IPNV, the reduction in viral load caused by pPG-612-CK6-VP2/〈em〉L. casei〈/em〉 393 was significantly higher than that of the other groups. Thus, the recombinant pPG-612-CK6-VP2/〈em〉L. casei〈/em〉 393 is a promising candidate for the development of an oral vaccine against IPNV.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 83〈/p〉 〈p〉Author(s): Nan Chen, Jingjing Jiang, Xiaojian Gao, Xixi Li, Yue Zhang, Xiaodan Liu, Hui Yang, Xuwen Bing, Xiaojun Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hemorrhagic septicemia of mandarin fish (〈em〉Siniperca chuatsi〈/em〉) was mainly caused by 〈em〉Aeromonas hydrophila〈/em〉 which was an opportunistic pathogen. In recent years, the disease has caused tremendous economic loss with high morbidity and mass mortality in the mandarin fish breeding industry. Histopathological analysis and the immune related gene expression profiles of mandarin fish (〈em〉S. chuatsi〈/em〉) infected with 〈em〉A. hydrophila〈/em〉 were investigated in this study. Transmission electron microscopy (TEM) images showed that the cells of 〈em〉A. hydrophila〈/em〉 densely covered with a mass of fimbriae. Histopathological analysis revealed that inflammation, vacuolization and extensive necrosis existed in the gill, liver, spleen and head kidney of the diseased fish. Quantitative real-time PCR was performed to measure mRNA expression levels for six immune related genes in mandarin fish after 〈em〉A. hydrophila〈/em〉 infection. The transcriptional analysis of these immune related genes demonstrated that the expression levels of major histocompatibility complex class II (MHC II), T cell receptor α (TCRα), tumor necrosis factor α (TNFα), CC chemokine 3, interleukin 8 (IL-8) and Hepcidin were strongly up-regulated in spleen and head kidney of mandarin fish post-infection. These results will contribute to further study on the pathogenesis and host defensive system in 〈em〉A. hydrophila〈/em〉 infection.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 86〈/p〉 〈p〉Author(s): Fan-Bin Zhan, Ivan Jakovlić, Wei-Min Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Interferon regulatory factor (Irf) family represents one of the most important transcription factor families, with multiple biological roles. In this study, we characterized five Irf family members (〈em〉irf4a, irf4b, irf6, irf8 and irf10〈/em〉) in 〈em〉Megalobrama amblycephala〈/em〉 at the cDNA and (predicted) amino acid levels, analyzed them phylogenetically, and developed gene-specific primers for qPCR analysis. All five 〈em〉irfs〈/em〉 were constitutively expressed in all examined tissues, but their transcription was significantly higher in lymphoid organs and tissues, such as kidney, spleen and intestine. Exceptions were 〈em〉irf8〈/em〉, which was expressed at a high level in heart and brain tissues, and 〈em〉irf6〈/em〉, expressed at low levels in most tissues. After a bacterial immune challenge with 〈em〉Aeromonas hydrophila,〈/em〉 the expression of 〈em〉irfs〈/em〉 in liver was up-regulated: 〈em〉mairf4a〈/em〉 8.12-fold〈em〉, mairf4b〈/em〉 29.9-fold〈em〉, mairf6〈/em〉 1.38-fold and 〈em〉mairf10〈/em〉 1.65-fold (〈em〉mairf8〈/em〉 was an exception: 0.07-fold). In spleen, kidney, intestine and gills, transcript levels of studied 〈em〉irfs〈/em〉 increased only at specific time-points. The results suggested that irfs are involved in the immune response to bacterial infection in 〈em〉M. amblycephala〈/em〉, which will help elucidate the biological functions of irfs in the immune system of teleost fish.〈/p〉〈/div〉 〈/div〉