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Yellow catfish (Pelteobagrus fulvidraco) is an important aquaculture fish susceptible to Aeromonas veronii infection, which causes acute death resulting in huge economic losses. Understanding the molecular processes of host immune defense is indispensable to disease control. Here, we conducted the integrated and comparative analyses of the transcriptome and metabolome of yellow catfish in response to A. veronii infection at the invaded stage and recovering stage. The crosstalk between A. veronii-induced genes and metabolites uncovered the key biomarkers and pathways that strongest contribute to different response strategies used by yellow catfish at corresponding defense stages. We found that at the A. veronii invading stage, the immune defense was strengthened by synthesizing lipids with energy consumption to repair the skin defense line and accumulate lipid droplets promoting intracellular defense line; triggering an inflammatory response by elevating cytokine IL-6, IL-10 and IL-1β following PAMP-elicited mitochondrial signaling, which was enhanced by ROS produced by impaired mitochondria; and activating apoptosis by up-regulating caspase 3, 7 and 8 and Prostaglandin F1α, meanwhile down-regulating FoxO3 and BCL6. Apoptosis was further potentiated via oxidative stress caused by mitochondrial dysfunction and exceeding inflammatory response. Additionally, cell cycle arrest was observed. At the fish recovering stage, survival strategies including sugar catabolism with D-mannose decreasing; energy generation through the TCA cycle and Oxidative phosphorylation pathways; antioxidant protection by enhancing Glutathione (oxidized), Anserine, and α-ketoglutarate; cell proliferation by inducing Cyclin G2 and CDKN1B; and autophagy initiated by FoxO3, ATG8 and ATP6V1A were highlighted. This study provides a comprehensive picture of yellow catfish coping with A. veronii infection, which adds new insights for deciphering molecular mechanisms underlying fish immunity and developing stage-specific disease control techniques in aquaculture. [ABSTRACT FROM AUTHOR]

Background: Long non-coding RNAs (lncRNAs) structurally resemble mRNAs and exert crucial effects on host immune defense against pathogen infection. Japanese flounder (Paralichthys olivaceus) is an economically important marine fish susceptible to Vibrio anguillarum infection. To date, study on lncRNAs in flounder is scarce. Results: Here, we reported the first systematic identification and characterization of flounder lncRNAs induced by V. anguillarum infection at different time points. A total of 2,368 lncRNAs were identified, 414 of which were differentially expressed lncRNAs (DElncRNAs) that responded significantly to V. anguillarum infection. For these DElncRNAs, 3,990 target genes (named DETGs) and 42 target miRNAs (named DETmiRs) were identified based on integrated analyses of lncRNA-mRNA and lncRNA-miRNA expressions, respectively. The DETGs were enriched in a cohort of functional pathways associated with immunity. In addition to modulating mRNAs, 36 DElncRNAs were also found to act as competitive endogenous RNAs (ceRNAs) that regulate 37 DETGs through 16 DETmiRs. The DETmiRs, DElncRNAs, and DETGs formed ceRNA regulatory networks consisting of 114 interacting DElncRNAs-DETmiRs-DETGs trinities spanning 10 immune pathways. Conclusions: This study provides a comprehensive picture of lncRNAs involved in V. anguillarum infection. The identified lncRNAs and ceRNA networks add new insights into the anti-bacterial immunity of flounder. [ABSTRACT FROM AUTHOR]

Megalocytivirus is a serious viral pathogen to many farmed fish including Japanese flounder (Paralichthys olivaceus). In this study, in order to systematically identify host immune genes induced by megalocytivirus infection, we examined the transcription profiles of flounder infected by megalocytivirus for 2, 6, and 8 days. Compared with uninfected fish, virus-infected fish exhibited 1242 differentially expressed genes (DEGs), with 225, 275, and 877 DEGs occurring at 2, 6, and 8 days post infection, respectively. Of these DEGs, 728 were upregulated and 659 were downregulated. The majority of DEGs were time-specific and formed four distinct expression profiles well correlated with the time of infection. The DEGs were classified into diverse Gene Ontology (GO) functional terms and enriched in 27 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, approximately one third of which were related to immunity. Weighted co-expression network analysis (WGCNA) was used to identify 16 key immune DEGs belonging to seven immune pathways (RIG-I-like receptor signaling pathway, JAK-STAT signaling pathway, TLR signaling pathway, cytokine-cytokine receptor interaction, phagosome, apoptosis, and p53 signaling pathway). These pathways interacted extensively and formed complicated networks. This study provided a global picture of megalocytivirus-induced gene expression profiles of flounder at the transcriptome level and uncovered a set of key immune genes and pathways closely linked to megalocytivirus infection. These results provided a set of targets for future delineation of the key factors implicated in the anti-megalocytivirus immunity of flounder. • A total of 1242 differentially expressed genes were induced by megalocytivirus. • The expressions of the DEGs were highly time-dependent and clustered into 4 groups. • Sixteen key immune genes forming complex networks with each other were identified. • The interactive key genes belonged to 7 immune pathways vital to antiviral immunity. [ABSTRACT FROM AUTHOR]

Japanese flounder (Paralichthys olivaceus) is one of the most economically important marine fish cultured in north Asia. Vibrio anguillarum is a severe bacterial pathogen to Japanese flounder and many other aquaculture species. In order to understand the immune response of flounder during bacterial infection, we systematically examined the transcriptome profiles of flounder spleen at three time points after V. anguillarum challenge. More than one billion high quality reads were obtained, approximately 80.70% of which were successfully mapped to the reference genome of flounder. A total of 6060, 4688 and 4235 differentially expressed genes (DEGs) were captured at 6, 12 and 24-h post-infection, respectively. The DEGs exhibited dynamic changes in expression and were assigned into four different profiles based on expression trend. GO and KEGG analysis showed that the DEGs were enriched in various immune-related terms, including response to stimulation, immune system and pathways of cytokine-cytokine receptor interaction, Jak-STAT signaling and Toll-like receptor signaling. Furthermore, a network of highly interactive DEGs involved in 11 immune-related pathways was detected by utilizing the weighted co-expressing network analysis (WGCNA). Accordingly, 26 hub genes were discovered that constituted an elaborate immune regulatory network and functioned mainly in pathogen recognition, antigen processing, and molecular signaling. The results of this study provided the first systematical transcriptome profile of flounder in association with V. anguillarum infection and can serve as a valuable resource of target genes for future studies on the molecular mechanisms underlying the immune defense of flounder against bacterial infection. • Vibrio anguillarum -induced transcriptome profiles of flounder were investigated. • A total of 8923 differentially expressed genes (DEGs) were found at 6, 12 and 24 hpi. • Co-expression networks of immune relevant DEGs were constructed. • Twenty-six hub genes with multiple interactions were identified. • The hub genes represented mainly genes involved in immune defense against pathogens. [ABSTRACT FROM AUTHOR]

• Hypoxia induces complicated miRNA responses in crabs. • The lasting of hypoxia exposure increases the dysbiosis in crabs. • Hypoxia responsive miRNAs regulate adaptations via HIF-1, immunity and endocrine. • A miRNA-mRNA network is highly involved in crab hypoxia response. Hypoxia caused by global climate change and human activities has become a growing concern eliciting serious damages to aquatic animals. microRNAs (miRNAs) as non-coding regulatory RNAs exert vital effects on hypoxia responses. Chinese mitten crab (Eriocheir sinensis) with the habitat on the sediment surface or the pond bottom is susceptible to oxygen deficiency. However, whether miRNAs are involved in the response of the crabs to hypoxia stress remains enigmas. In this study, we conducted the whole transcriptome-based miRNA-mRNA integrated analysis of Chinese mitten crab gill under hypoxic condition for 3 h and 24 h We found that the acute hypoxia induces complex miRNA responses with the extensive influences on their target genes that engaged in various bio-processes, especially those associated with immunity, metabolism and endocrine. The impact of hypoxia on crab miRNAs is severer, as the exposure lasts longer. In response to the dissolved oxygen fluctuation, the HIF-1 signaling is activated by miRNAs to cope with the hypoxia stress through strategies including balancing inflammatory and autophagy involved in immunity, changing metabolism to reducing energy consumption, and enhancing oxygen-carrying and delivering capacities. The miRNAs and their corresponding target genes engaged in hypoxia response were intertwined into an intricate network. Moreover, the top hub molecular, miR-998-y and miR-275-z, discovered from the network might serve as biomarkers for hypoxia response in crabs. Our study provides the first systemic miRNA profile of Chinese mitten crab induced by hypoxia stress, and the identified miRNAs and the interactive network add new insights into the mechanism of hypoxia response in crabs. [ABSTRACT FROM AUTHOR]

Background: Skull base osteoradionecrosis is a devastating post-irradiation complication in nasopharyngeal carcinoma patients. We conducted a retrospective analysis to assess the long-term survival and prognostic factors of patients with skull base osteoradionecrosis treated with endoscopic sequestrectomy.Methods: We enrolled 59 nasopharyngeal carcinoma patients with skull base osteoradionecrosis who underwent endoscopic nasopharyngectomy. The clinical characteristics and outcome at the last follow-up visit were collected. The survival curve and univariate and multivariate survival analysis were analyzed by Kaplan-Meier and Cox proportional hazards model to analyze the potential prognostic factors of overall survival, including age, gender, number of radiation, number of operations, extension of disease (local or extensive), whether the ICA is exposed to the procedure (yes or no) and the hypha status (yes or no) at postoperative pathological examination.Results: The predilection sites of skull base osteoradionecrosis in osteoradionecrosis patients are as follows: the base of the sphenoid bone and sphenoid sinus region, the clivus and petrous apex region including the internal carotid canal and the pterygoid process region (including its medial and lateral pterygoid plates). After surgery, clinical symptoms were alleviated in most patients to varying degrees. By the last follow-up visit, 26 patients had died. Most deaths (24) in the study occurred during the first 2 years. Most patients (24) died of sudden severe hemorrhage. The follow-up period ranged from 1 to 108 months, with a median of 27 months. The 2-year overall survival rate was 54.2%. Multivariate Cox regression analysis showed that the number of radiation (P = 0.026) and age (P = 0.002) were independent risk factors for the overall survival.Conclusions: Endoscopic sequestrectomy with minimal complications and clear vision is a valuable option for the therapy of skull base osteoradionecrosis in nasopharyngeal carcinoma patients. [ABSTRACT FROM AUTHOR]

Myeloid differentiation factor 88 (MyD88) is a pivotal adaptor in the TLR/IL-1R signaling pathway, which plays an important role in activating the innate immune system. Although MyD88 genes have been identified in a variety of species, they have not been systematically characterized in scallops. In this study, five MyD88 genes were identified in Yesso scallop ( Patinopecten yessoensis ), PyMyD88-1 , PyMyD88-2a , PyMyD88-2b , PyMyD88-3 and PyMyD88-4 , which consisted of two pairs of tandem duplications located on the same chromosome. To our knowledge, this is the largest number of MyD88 genes found in an invertebrate. Phylogenetic and protein structural analyses were carried out to determine the identities and evolutionary relationships of these genes. PyMyD88 s have highly conserved structures compared to MyD88 genes from other invertebrate species, except for PyMyD88-4 , which contains only a DD domain, suggesting the evolutionarily conserved form of this particular gene member. We investigated the expression profiles of PyMyD88 genes at different developmental stages and in healthy adult tissues and hemocytes after Micrococcus luteus and Vibrio anguillarum infection using quantitative real-time PCR (qRT-PCR). The expression of most PyMyD88 s was significantly induced in the acute phase (3–6 h) after infection with both gram-positive ( M. luteus ) and gram-negative ( V. anguillarum ) bacteria, with much more dramatic changes in PyMyD88 expression being observed after V. anguillarum challenge. Collectively, the abundance of MyD88 s and their specific expression patterns provide insight into their versatile roles in the response of the bivalve innate immune system to gram-negative bacterial pathogens. [ABSTRACT FROM AUTHOR]

Carotenoids are a diverse group of red, orange, and yellow pigments that act as vitamin A precursors and antioxidants. Animals can only obtain carotenoids through their diets. Amongst the carotenoids identified in nature, over one third are of marine origin, but current research on carotenoid absorption in marine species is limited. Bivalves possess an adductor muscle, which is normally white in scallops. However, a new variety of Yesso scallop ( Patinopecten yessoensis ), the ‘Haida golden scallop’, can be distinguished by its adductor muscle's orange colour, which is caused by carotenoid accumulation. Studying the genes related to carotenoid accumulation in this scallop could benefit our understanding of the mechanisms underlying carotenoid absorption in marine organisms, and it could further improve scallop breeding for carotenoid content. Stearoyl-CoA desaturase (SCD) is the rate-limiting enzyme in the production of monounsaturated fatty acids, which enhance carotenoid absorption. Here, the full-length cDNA and genomic DNA sequences of the SCD gene from the Yesso scallop ( PySCD ) were obtained. The PySCD gene consisted of four exons and three introns, and it contained a 990-bp open reading frame encoding 329 amino acids. It was ubiquitously expressed in adult tissues, embryos and larvae of both white Yesso scallops and ‘Haida golden’ scallops. Although the expression pattern of PySCD in both types of scallops was similar, significantly more PySCD transcripts were detected in the ‘Haida golden’ scallops than in the white scallops. Elevated PySCD expression was found in tissues including the adductor muscle, digestive gland, and gonad, as well as in veliger larvae. This study represents the first characterisation of an SCD gene from the Mollusca . Our data imply that PySCD functions in multiple biological processes, and it might be involved in carotenoid accumulation. [ABSTRACT FROM AUTHOR]

Circular RNA (circRNA) is a new class of non-coding RNA that is structured into a closed loop without polyadenylation. Recent studies showed that circRNAs are involved in the host immune response to pathogen infection. Japanese flounder (Paralichthys olivaceus), an important economical marine fish cultured in north Asia, is affected by Vibrio anguillarum, a pathogenic bacterium that can infect a large number of fish. In this study, we systematically explored the circRNAs in the spleen of V. anguillarum-infected flounder at different infection time points. A total of 6581 circRNAs were identified, 148 of which showed differential expression patterns after V. anguillarum infection and were named DEcirs. Most of the DEcirs were strongly time-specific. The parental genes of the DEcirs were identified and functionally classified into diverse pathways, including immune-related pathways. Among the immune-related DEcirs, seven were predicted to sponge 18 targeted miRNAs that were differentially expressed during V. anguillarum infection (named DETmiRs). Further analysis showed that the DEcirs and their corresponding DETmiRs intertwined into complicated immune related networks. These results indicate that in flounder, circRNAs are regulated by V. anguillarum and form interactive networks with mRNAs and miRNAs that likely play important roles in the immune defense against pathogen infection. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are non-coding regulatory RNAs that play a vital part in the host immune response to pathogen infection. Japanese flounder (Paralichthys olivaceus) is an important aquaculture fish species that has suffered from bacterial diseases, including that caused by Vibrio anguillarum infection. In a previous study, we examined the messenger RNA (mRNA) expression profiles of flounder during V. anguillarum infection and identified 26 hub genes in the flounder immune response. In this study, we performed the micro-transcriptome analysis of flounder spleen in response to V. anguillarum infection at 3 different time points. Approximately 277 million reads were obtained, from which 1218 miRNAs were identified, including 740 known miRNAs and 478 novel miRNAs. Among the miRNAs, 206 were differentially expressed miRNAs (DEmiRs), and 104 of the 206 DEmiRs are novel miRNAs identified for the first time. Most of the DEmiRs were strongly time-dependent. A total of 1355 putative target genes of the DEmiRs (named DETGs) were identified based on integrated analysis of miRNA-mRNA expressions. The DETGs were enriched in multiple functional categories associated with immunity. Thirteen key DEmiRs and 66 immune DETGs formed an intricate regulatory network constituting 106 pairs of miRNAs and DETGs that span five immune pathways. Furthermore, seven of the previously identified hub genes were found to be targeted by 73 DEmiRs, and together they formed interlinking regulatory networks. These results indicate that V. anguillarum infection induces complicated miRNA response with extensive influences on immune gene expression in Japanese flounder. [ABSTRACT FROM AUTHOR]

Drawing upon the citizenship motives framework and voice research, this study theorizes that both organizational concern (OC) and impression management (IM) motives are key predictors of employee promotive and prohibitive voice. This study further explores the moderating effect of perceived voice level in the work context on the relationships between motives and voice. The results of 140 pairings of supervisor-subordinate dyads indicate that both OC and IM motives are determinants of promotive and prohibitive voice. Moreover, perceived voice level in the work context plays distinct roles in moderating the main effects of motives on voice. Specifically, perceived voice level in the work context mitigates the influence of OC motives on promotive and prohibitive voice, whereas it strengthens the impact of IM motives on promotive and prohibitive voice. This study provides implications for both theory and practice. Limitations and future directions are also discussed. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) act as competing endogenous RNAs, which are involved in the regulation of many types of cancers. They primarily function by sponging microRNAs (miRNAs) and influencing the expression of miRNA by target messenger RNA. However, the role of circRNAs in the progression of nasopharyngeal carcinoma (NPC) remains largely unclear. In this study, differentially expressed miRNAs associated with NPC were screened using microarray analyses, from which miR-107 was identified. Increased miR-107 expression was associated with poor prognosis in NPC, and miR-107 promoted the proliferation and migration of NPC cells. TGFBR2 was identified as the direct target of miR-107, which could reverse its effect on NPC cells. Furthermore, the expression of circTGFBR2 was downregulated in NPC tissue samples, while circTGFBR2 overexpression correlated with favorable prognosis in NPC. Functionally, circTGFBR2 overexpression inhibited the proliferation and migration of NPC cells both in vitro and in vivo. Further analysis showed that circTGFBR2 sponged miR-107, leading to the upregulation of TGFBR2 expression and suppression of NPC progression. Therefore, circTGFBR2 may serve as a novel tumor suppressive factor and potential target for new therapies in NPC patients. [ABSTRACT FROM AUTHOR]

• Ribosome profiling was used to study response to environmental stress in fish. • Hypoxia led to profound effect on transcription, translation and protein level in brain. • HIF signaling, autophagy and glycolysis/gluconeogenesis were activated by hypoxia. • Hypoxia disturbed brain function via dysregulated autophagy in yellow catfish. Brain plays a central role in adapting to environmental changes and is highly sensitive to the oxygen level. Although previous studies investigated the molecular response of brain exposure to acute hypoxia in fish, the lack of studies at the translational level hinders further understanding of the regulatory mechanism response to hypoxia from multi-omics levels. Yellow catfish (Pelteobagrus fulvidraco) is an important freshwater aquaculture species; however, hypoxia severely restricts the sustainable development of its breeding industry. In the present study, the transcriptome, translatome, and proteome were integrated to study the global landscapes of yellow catfish brain response to hypoxia. The evidently increased amount of cerebral cortical cells with oedema and pyknotic nuclei has been observed in hypoxia group of yellow catfish. A total of 2750 genes were significantly changed at the translational level. Comparative transcriptional and translational analysis suggested the HIF-1 signaling pathway, autophagy and glycolysis/gluconeogenesis were up-regulated after hypoxia exposure. KEGG enrichment of translational efficiency (TE) differential genes suggested that the lysosome and autophagy were highly enriched. Our result showed that yellow catfish tends to inhibit the TE of genes by increasing the translation of uORFs to adapt to hypoxia. Correlation analysis showed that transcriptome and translatome exhibit higher correlation. In summary, this study demonstrated that hypoxia dysregulated the cerebral function of yellow catfish at the transcriptome, translatome, and proteome, which provides a better understanding of hypoxia adaptation in teleost. [ABSTRACT FROM AUTHOR]

Unlike mammalian red blood cells (RBCs), fish RBCs are nucleated and thus capable of gene expression. Japanese flounder (Paralichthys olivaceus) is a species of marine fish with important economic values. Flounder are susceptible to Edwardsiella tarda, a severe bacterial pathogen that is able to infect and survive in flounder phagocytes. However, the infectivity of and the immune response induced by E. tarda in flounder RBCs are unclear. In the present research, we found that E. tarda was able to invade and replicate inside flounder RBCs in both in vitro and in vivo infections. To investigate the immune response induced by E. tarda in RBCs, transcriptome analysis of the spleen RBCs of flounder challenged with E. tarda was performed. Six sequencing libraries were constructed, and an average of 43 million clean reads per library were obtained, with 85% of the reads being successfully mapped to the genome of flounder. A total of 1720 differentially expressed genes (DEGs) were identified in E. tarda-infected fish. The DEGs were significantly enriched in diverse Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, especially those associated with immunity, disease, and infection. Ninety-one key DEGs involved in 12 immune-related pathways were found to form extensive interaction networks. Twenty-one genes that constituted the hub of the networks were further identified, which were highly regulated by E. tarda and involved in a number of immune processes, notably pathogen recognition and signal transduction, antigen processing and presentation, inflammation, and splicing. These results provide new insights into the immune role of flounder RBCs during bacterial infection. [ABSTRACT FROM AUTHOR]

Edwardsiella tarda is a Gram-negative bacterial pathogen with a broad host range, including fish, reptiles, and mammals. One prominent virulence feature of E. tarda is its ability to survive and replicate in host phagocytes, but the relevant molecular mechanism is largely unknown. In this study, we examined the transcriptome profiles of RAW264.7 cells, a murine macrophage cell line, infected with live E. tarda or stimulated with dead E. tarda for 4 h and 8 h. Eighteen libraries were constructed, and an average of 69 million clean reads per library were obtained, with ~81.63% of the reads being successfully mapped to the reference genome. In total, 208 and 232 differentially expressed genes (DEGs) were identified between live and dead E. tarda-treated cells at 4 h and 8 h post-infection, respectively. The DEGs were markedly enriched in the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways associated with immunity. Live E. tarda differed strikingly from dead E. tarda in the regulation of immune related genes. Compared with dead E. tarda-treated cells, live E. tarda-treated cells exhibited marked and significant suppression in the induction of a large amount of immune genes, including RIG-I-like receptors, cytokines, and interferon-related genes. Furthermore, some of the immune genes highly regulated by live E. tarda formed complicated interaction networks with each other. Together, the results of this study revealed a transcriptome profile specifically induced by the active virulence elements of live E. tarda during the infection process, thus adding new insights into the intracellular infection mechanism of E. tarda. This study also provided a valuable set of target genes for further study of the immune evasion strategy of E. tarda. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of chronic exposure to copper nanoparticles (Cu-NPs) and waterborne copper (CuSO 4) on the reproductive system of yellow catfish (Pelteobagrus fulvidraco). Juvenile yellow catfish were exposed to 100 and 200 μg Cu/L Cu-NPs and 100 μg Cu/L CuSO 4 for 42 days. The results showed clear reproductive defects in both female and male yellow catfish in the 200 μg Cu/L Cu-NPs and 100 μg Cu/L CuSO 4 groups. Exposure to Cu-NPs or CuSO 4 inhibited folliculogenesis and vitellogenesis in the ovaries, and spermatogenesis in the testes, accompanied by elevation of the apoptotic signal. Ultrastructural observations also revealed damaged organelles of gonadal cells in both testes and ovaries. Most of the hypothalamic-pituitary-gonadal (HPG) axis genes examined and serum sex steroid hormones tended to be downregulated after Cu exposure. Metabolomic analysis suggested that gonadal estradiol level is sensitive to Cu-NPs or CuSO 4. The heat map of gonadal metabolomics suggested a similar effect of 200 μg Cu/L Cu-NPs and 100 μg Cu/L CuSO4 in both the ovaries and testes. Additionally, metabolomics data showed that the reproductive toxicity due to Cu-NPs and CuSO 4 may occur via different metabolic pathways. Cu-NPs tend to dysregulate the metabolic pathways of sphingolipid and linoleic acid metabolism in the ovary and the biosynthesis of amino acids and pantothenate and CoA in the testis. Overall, these findings revealed the toxicological effects of Cu-NPs and CuSO 4 on the HPG axis and gonadal metabolism in yellow catfish. [Display omitted] • The HPG axis and gonadal metabolites was dysregulated by Cu-NPs and CuSO 4. • Cu-NPs and CuSO 4 suppressed the gonadal development and gametogenesis. • Ultrastructure of gonadal cells was disrupted by accumulated Cu ions and/or Cu-NPs. • Reproductive system may have different metabolic response to Cu-NPs and CuSO 4. [ABSTRACT FROM AUTHOR]

• Hypoxia stress damaged intestinal morphology and barrier in Eriocheir sinensis. • Hypoxia stress induced antioxidant and immune response, and apoptosis in intestine of Chinese mitten crab. • The diversity and composition of gut microbiota were perturbed by hypoxia stress and reoxygenation. • Hypoxia stress and reoxygenation induced changes in gut microbiota were closely related with hepatopancreas and gut health. Hypoxia causes irreversible damage to aquatic animals. However, few reports have explored the effect of hypoxia stress and reoxygenation on intestinal homeostatic imbalance and consequent hepatopancreas-intestine axis health in crustacean. Herein, 180 Chinese mitten crabs (Eriocheir sinensis) were equally divided into control (DO 7.0 ± 0.2 mg/L) and treatment groups. The treatment group was exposed with continuous hypoxic stress (DO 3.0 ± 0.1 mg/L) for 96 h and then reoxygenated (DO 6.9 ± 0.1 mg/L) for 96 h. The effects on intestines and hepatopancreas of Chinese mitten crab were investigated, and the role of gut microbiota in hypoxia induced damages was explored. Hypoxia impaired intestinal tissue structure, and decreased swelling and the number of goblet cells, which are features that did not significantly improve after reoxygenation. With prolonged hypoxic stress, the activities of antioxidant enzymes (LDH, SOD and CAT) and MDA content in intestine were significantly elevated. Moreover, the level of oxidative stress increased, which led to upregulated apoptosis rate and expression of apoptosis-related genes (Caspase 3, Caspase 8 and BAX). In addition, the expression of immune related genes (MyD88, ALF1, Relish and Crustin) in hepatopancreas and intestine was both significantly induced under hypoxia, which activated the immune defense mechanism of Chinese mitten crab to adapt to the hypoxic environment. Furthermore, diversity and relative abundance of gut microbiota decreased noticeably during hypoxic stress; the number of beneficial bacteria downregulated. Finally, KEGG pathway analysis revealed that nine pathways were significantly enriched in intestinal microorganisms, including autoimmune disease and environmental adaptation. Collectively, these results suggested that hypoxia negatively affected E. sinensis health by triggering oxidative stress, altering the composition of the gut microbiota and inhibiting the immune response. [ABSTRACT FROM AUTHOR]

Competitive endogenous RNAs (ceRNAs) have emerged as essential immune regulators bridging the non-coding RNAs (ncRNAs) and mRNAs in mammals, generating interactive networks across the transcriptome as a whole. In fish immunity, ceRNA trinities, consisted of long ncRNAs (lncRNAs), microRNAs (miRNAs) and mRNAs, are reported sporadically. To date, the involvement of ceRNAs in yellow catfish (Pelteobagrus fulvidraco) is unknown. Here, we reported the first lncRNA-mediated ceRNA network in yellow catfish infected with Aeromonas veronii (A. veronii) for different time points. The linear ncRNAs, including miRNAs and lncRNAs, were systematically identified and characterized, especially those were differentially expressed induced by A. veronii stimulation (named DEmiRs and DElncs). These DEmiRs and DElncs extensively influenced the expression of immune genes as well as lipid metabolic genes by direct interaction. In particular, DElncs in yellow catfish were found to act as ceRNAs that modulate target genes (ceDETGs) through sponging corresponding DEmiRs. Accordingly, a key ceRNA network was constructed based on the results of functional enrichment and the connectivity of ceDETGs. This ceRNA network consisted of 44 DElncs, 6 DEmiRs and 15 ceDETGs, regulating a dual function of immunity and lipid remodeling in response to A. veronii infection. The results of this study provide a comprehensive picture of the ceRNA regulatory network engaged in yellow catfish defense response. The obtained ncRNAs and dual-function ceRNA network add new insights into the anti-bacterial immunity of teleost fish. • A. veronii infection induced complicated miRNA and lncRNA responses. • The A. veronii induced ncRNAs affected both immune and lipid metabolic genes. • ceRNA crosstalk occurred in yellow catfish during bacterial infection. • A key dual-function ceRNA network was highly involved in fish defense response. [ABSTRACT FROM AUTHOR]

• The first study on blood redistribution in P. vachelli under hypoxic stress. • P. vachelli preferentially protect vital organs under hypoxic stress. • The brain, liver, and muscle of P. vachelli are severely damaged under severe hypoxi. Blood redistribution occurs in mammals under hypoxia but has not been reported in fish. This study investigated the tissue damage, hypoxia-inducible factor (HIF) activation level, and blood flow changes in the brain, liver, and muscle of Pelteobagrus vachelli during the hypoxia process for normoxia-hypoxia-asphyxia. The results showed that P. vachelli has tissue specificity in response to hypoxic stress. Cerebral blood flow increased with less damage than in the liver and muscle, suggesting that P. vachelli may also have a blood redistribution mechanism in response to hypoxia. It is worth noting that severe hypoxia can lead to a sudden increase in the degree of brain tissue damage. In addition, higher dissolved oxygen levels activate HIF and may have contributed to the reduced damage observed in the brain. This study provides basic data for investigating hypoxic stress in fish. [ABSTRACT FROM AUTHOR]

Nasopharyngeal carcinoma (NPC) is a common cancer occurring primarily in East Asia and Africa. The high rate of recurrence and metastasis of NPC continuously endangers the health of patients. The present study aimed to identify the underlying mechanisms involved in the progression of NPC and provide experimental basis to develop a novel and efficient agent against NPC. The present study measured the expression level of tripartite motif containing 24 (TRIM24) in tumor tissues from NPC patients using reverse transcription quantitative polymerase chain reaction. Subsequently, Cell Counting kit-8 and flow cytometry were used to detect the cell proliferation and apoptosis of NPC cell lines HONE1 and CNE1 cells where the TRIM24 gene was knocked-down with small interfering RNA (siRNA). Further, caspase kits and western blot analysis were used to detect the expression of apoptosis and angiogenesis-associated proteins. The present study detected a higher expression level of TRIM24 in tumor tissues and NPC cell lines and lower cell viability and higher apoptotic rate were observed when TRIM24 was silenced. Meanwhile, upregulated caspase-3 and caspase-9 indicated induced cell apoptosis in HONE1 and CNE1 cells following the treatment with TRIM24 siRNA. Additionally, the downregulated expression level of vascular endothelial growth factor (VEGF) and VEGF receptor 2 suggested inhibited angiogenesis of NPC cells. Additionally, the reduced levels of janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) indicated a blocked JAK2/STAT3 signaling pathway. However, there was no direct evidence that inactivation of the JAK2/STAT3 signaling pathway was involved in regulation of siTRIM24, these results suggested that TRIM24 has an important role in the growth of NPC. Additionally, silenced TRIM24 may lead to inhibited cell proliferation and induced cell apoptosis in NPC cells. The limitation of this study was that HONE1, CNE1 and CNE2 cells may have been contaminated with other cells. Further experiments with validated NPC cells may be needed. [ABSTRACT FROM AUTHOR]

Hypoxia has become a significant issue both in open aquatic environment and closed aquaculture system. Development of hypoxia-tolerant breeds is one of the practical strategies in further fish farming. In present study, the hybrid Pelteobagrus fulvidraco (PF) × Leiocassis longirostris (LL) was generated by artificial insemination. Both PF ♀ × LL ♂ and LL ♀ × PF ♂ could produce F 1 offspring, assigned as hybrid PL and hybrid LP, respectively. The hybrid PL exhibited higher hatching rate, expectant morphological traits, and an improved trait on hypoxia-tolerance compared to hybrid LP. However, the growth trait was not strengthened at early development stage until 90 dpf compared to hybrid LP and LL. To further examine the hypoxia-tolerant machinery of the hybrid PL strain, we systematically investigated the tissues morphology, hypoxia inducible factor (HIF)-related genes expression, and oxidative stress enzymes activity of gill, liver, and intestine under acute hypoxia and reoxygenation. The histological results showed that the interlamellar cell mass was expanded in the gill, obvious vacuolation and swell of hepatocytes was found in the liver, and expanded submucosa was observed in the intestine, suggesting the tissues remodeling was evidenced in hybrid PL responding to hypoxia. A rapid HIF-related genes response (Hif-1α , Hif-2α , Vhl , Fih-1 , Phd3 , and Vegf-a) and activation of anti-oxidant enzymes activity (T-SOD, CAT, and GPx) among three tissues were patently illustrated. Our results indicated that the complex combination of morphological, molecular, and biochemical adjustments might contribute jointly to the hypoxia-tolerance of hybrid PL. This study provided an alternative and possible method for hypoxia-tolerant fish strain generation using hybridization breeding in aquaculture. • Hybrid PL showed desirable morphologies and progressive traits on hypoxia-tolerance but not on early growth. • Hybrid PL displayed tissues remodeling, rapid HIF-related genes expression, and anti-oxidant defense during acute hypoxia. • Hybridization breeding would be a highly practical strategy for superior traits assembly in future aquaculture. [ABSTRACT FROM AUTHOR]

Tumor necrosis factors receptors (TNFRs) comprise a superfamily of proteins characterized by a unique cysteine-rich domain (CRD) and play important roles in diverse physiological and pathological processes in the innate immune system, including inflammation, apoptosis, autoimmunity and organogenesis. Although significant effects of TNFRs on immunity have been reported in most vertebrates as well as some invertebrates, the complete TNFR superfamily has not been systematically characterized in scallops. In this study, two different types of TNFR-like genes, including PyTNFR1 and PyTNFR2 g enes were identified from Yesso scallop ( Patinopecten yessoensis , Jay, 1857) through whole-genome scanning. Phylogenetic and protein structural analyses were carried out to determine the identities and evolutionary relationships of the two genes. The expression profiling of PyTNFRs was performed at different development stages, in healthy adult tissues and in hemocytes after bacterial infection and heat stress. Expression analysis revealed that both PyTNFRs were significantly induced during the acute phase (3 h) after infection with Gram-positive ( Micrococcus luteus ) and Gram-negative ( Vibrio anguillarum ) bacteria, though much more dramatic chronic-phase (24 h) changes were observed after V. anguillarum challenge. For heat stress, only PyTNFR2 displayed significant elevation at 12 h and 24 h, which suggests a functional difference in the two PyTNFRs. Collectively, this study provides novel insight into the PyTNFRs and the specific role and response of TNFR-involved pathways in host immune responses against different bacterial pathogens and heat stress in bivalves. [ABSTRACT FROM AUTHOR]

Mitogen-activated protein kinase kinases (MKK) are the essential components of the evolutionarily conserved MAPK signaling cascade, which regulates a variety of cellular activities and innate immune responses. Although MKK genes have been extensively studied in various vertebrate and invertebrate species, they have not been systematically characterized in bivalves. In this study, we identified and characterized five MKK genes ( PyMKK1/2 , PyMKK4 , PyMKK5 , PyMKK3/6 and PyMKK7 ) in the Yesso scallop ( Patinopecten yessoensis ). Phylogenetic and protein structural analyses were conducted to determine their identities and evolutionary relationships. To gain insights into the possible roles of MKK genes during scallop innate immune responses, quantitative real-time PCR (qRT-PCR) was used to investigate their expression profiles during different developmental stages in samples taken from healthy adult tissues and hemocytes after Micrococcus luteus and Vibrio anguillarum bacterial infections. The Yesso scallop MKK s ( PyMKK s) were found to have highly conserved structural features compared to the MKK genes from other invertebrate species. Using qRT-PCR analysis, three distinct expression patterns were detected among the PyMKK s over the course of ten different developmental stages. In adult scallops, the majority of the PyMKK s were highly expressed in mantle, gill, muscle and hemocytes. The differential expression patterns of the five PyMKK s after M. luteus (Gram-positive) and V. anguillarum (Gram-negative) bacterial infections suggested their possible involvement in the innate immune response and provide the foundation and resource for the further study on innate immune response of MAPK signal pathway in mollusk. [ABSTRACT FROM AUTHOR]

Background: Scallops represent economically important aquaculture shellfish. The identification of genes and genetic variants related to scallop growth could benefit high-yielding scallop breeding. The insulin-like growth factor (IGF) system is essential for growth and development, with IGF binding proteins (IGFBPs) serving as the major regulators of IGF actions. Although an effect of IGF on growth was detected in bivalve, IGFBP has not been reported, and members of the IGF system have not been characterized in scallop. Results: We cloned and characterized an IGFBP (PyIGFBP) gene from the aquaculture bivalve species, Yesso scallop (Patinopecten yessoensis, Jay, 1857). Its full-length cDNA sequence was 1,445 bp, with an open reading frame of 378 bp, encoding 125 amino acids, and its genomic sequence was 10,193 bp, consisting of three exons and two introns. The amino acid sequence exhibited the characteristics of IGFBPs, including multiple cysteine residues and relatively conserved motifs in the N-terminal and C-terminal domains. Expression analysis indicated that PyIGFBP was expressed in all the tissues and developmental stages examined, with a significantly higher level in the mantle than in other tissues and a significantly higher level in gastrulae and trochophore larvae than in other stages. Furthermore, three single nucleotide polymorphisms (SNPs) were identified in this gene. SNP c.1054A>G was significantly associated with both shell and soft body traits in two populations, with the highest trait values in GG type scallops and lowest in AG type ones. Conclusion: We cloned and characterized an IGFBP gene in a bivalve, and this report also represents the first characterizing an IGF system gene in scallops. A SNP associated with scallop growth for both the shell and soft body was identified in this gene. In addition to providing a candidate marker for scallop breeding, our results also suggest the role of PyIGFBP in scallop growth. [ABSTRACT FROM AUTHOR]

• Carotenoids accumulation in scallop was tissue- and gender- biased. • 'Haida golden scallop' contains more carotenoids than normal scallop in most tissues. • The ratio of pectenolone to pectenoxanthin differs among scallop tissues. • Carotenoids content in muscle of 'Haida golden scallop' peaks in spawning season. Carotenoids are colored compounds with important physiological functions. The Haida golden scallop, which has an orange adductor muscle, is a carotenoid-enriched variety of scallop Mizuhopecten yessoensis , an important aquaculture shellfish. In this study, we investigated the tissue distribution of the carotenoids, pectenolone and pectenoxanthin, in both Haida golden scallop and normal Yesso scallop. Both carotenoids were detected in all the sampled tissues of the two scallops, except in the adductor muscle of normal scallop. There were significantly more carotenoids in Haida golden scallop than in normal scallop, in the tissues of the mantle, female gonad, kidney, and adductor muscle. Increased carotenoid concentrations were detected in Haida golden scallop adductor muscle during the spring spawning season, indicating the effects of reproduction on muscle carotenoids accumulation. This study was the first systematic investigation of carotenoid distribution in Yesso scallop tissues and will benefit future research on carotenoid accumulation and function in scallops. [ABSTRACT FROM AUTHOR]

Background:Bivalves comprise around 30,000 extant species and have received much attention for their importance in ecosystems, aquaculture and evolutionary studies. Despite the increasing application of real-time quantitative reverse transcription PCR (qRT-PCR) in gene expression studies on bivalve species, little research has been conducted on reference gene selection which is critical for reliable and accurate qRT-PCR analysis. For scallops, systematic evaluation of reference genes that can be used among tissues or embryo/larva stages is lacking, and β-actin (ACT) is most frequently used as qRT-PCR reference gene without validation. Results:In this study, 12 commonly used candidate reference genes were selected from the transcriptome data of Yesso scallop (Patinopecten yessoensis) for suitable qRT-PCR reference genes identification. The expression of these genes in 36 tissue samples and 15 embryo/larva samples under normal physiological conditions was examined by qRT-PCR, and their expression stabilities were evaluated using three statistic algorithms, geNorm, NormFinder, and comparative ∆Ct method. Similar results were obtained by the three approaches for the most and the least stably expressed genes. Final comprehensive ranking for the 12 genes combing the results from the three programs showed that, for different tissues, DEAD-box RNA helicase (HELI), ubiquitin (UBQ), and 60S ribosomal protein L16 (RPL16) were the optimal reference genes combination, while for different embryo/larva stages, gene set containing Cytochrome B (CB), Cytochrome C (CC), Histone H3.3 (His3.3), and Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were recommended for qRT-PCR normalization. ACT was among the least stable genes for both adult tissues and embryos/larvae. Conclusions:This work constitutes the first systematic analysis on reference genes selection for qRT-PCR normalization in scallop under normal conditions. The suitable reference genes we recommended will be useful for the identification of genes related to biological processes in Yesso scallop, and also in the reference gene selection for other scallop or bivalve species. [ABSTRACT FROM AUTHOR]