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Now showing items 1 - 15 of 15

  • Identification and expression profiling analysis of microRNAs in Nile tilapia (Oreochromis niloticus) in response to Streptococcus agalactiae infection

    Gao, Chengbin   Fu, Qiang   Yang, Ning   Song, Lin   Tan, Fenghua   Zhu, Jiajie   Li, Chao  

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  • Identification and mucosal expression analysis of cathepsin B in channel catfish (Ictalurus punctatus) following bacterial challenge.

    Li, Chao   Song, Lin   Tan, Fenghua   Su, Baofeng   Zhang, Dongdong   Zhao, Honggang   Peatman, Eric  

    The mucosal surfaces of fish (skin, gill and intestine) constitute the primary line of defense against pathogen invasion. Although the importance of fish mucosal surfaces as the first barriers against pathogens cannot be overstated, the knowledge of teleost mucosal immunity are still limited. Cathepsin B, a lysosomal cysteine protease, is involved in multiple levels of physiological and biological processes, and playing crucial roles for host immune defense against pathogen infection. In this regard, we identified the cathepsin B (ctsba) of channel catfish and investigated the expression patterns of the ctsba in mucosal tissues following Edwardsiella ictaluri and Flavobacterium columnare challenge. Here, catfish ctsba gene was widely expressed in all examined tissues with the lowest expression level in muscle, and the highest expression level in trunk kidney, followed by spleen, gill, head kidney, intestine, liver and skin. In addition, the phylogenetic analysis showed the catfish ctsba had the strongest relationship to zebrafish. Moreover, the ctsba showed a general trend of up-regulated in mucosal tissues following both Gram-negative bacterial challenge. Taken together, the increased expression of ctsba in mucosal surfaces indicated the protective function of ctsba against bacterial infection, and the requirement for effective clearance of invading bacteria. Further studies are needed, indeed, to expand functional characterization and examine whether ctsba may play additional physiological and biological roles in catfish mucosal tissues. Copyright =C2=A9 2015 Elsevier Ltd. All rights reserved.
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  • The involvement of cathepsin F gene (CTSF) in turbot (Scophthalmus maximus L.) mucosal immunity

    Gao, Chengbin   Fu, Qiang   Su, Baofeng   Song, Huanhuan   Zhou, Shun   Tan, Fenghua   Li, Chao  

    Cathepsin F (CTSF) is a recently described papain-like cysteine protease and unique among cathepsins due to an elongated N-terminal pro-region, which contains a cystatin domain. CTSF likely plays a regulatory role in processing the invariant chain which is associated with the major histocompatibility complex (MHC) class II. In this regard, we identified the CTSF gene of turbot as well as its protein structure, phylogenetic relationships, and expression patterns in mucosal tissues following Vibrio anguillarum and Streptococcus iniae challenge. We also determined the expression patterns of CTSF in mucosal tissues after vaccinated with the formalin-inactivated V. vulnificus whole-cell vaccine. Briefly, turbot CTSF gene showed the closest relationship with that of Paralichthys olivaceus in phylogenetic analysis. And CTSF was ubiquitously expressed in all tested tissues with the highest expression level in gill. In addition, CTSF gene showed different expression patterns following different bacterial challenge. The significant quick regulation of CTSF in mucosal surfaces against infection indicated its roles in mucosal immunity. Functional studies should further characterize avail utilization of CTSF function to increase the disease resistance of turbot in maintaining the integrity of the mucosal barriers against infection and to facilitate selection of the disease resistant family/strain in turbot. (C) 2017 Elsevier Ltd. All rights reserved.
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  • Identification and expression profiling analysis of microRNAs in Nile tilapia (Oreochromis niloticus) in response to Streptococcus agalactiae infection

    Gao, Chengbin   Fu, Qiang   Yang, Ning   Song, Lin   Tan, Fenghua   Zhu, Jiajie   Li, Chao  

    MicroRNAs (miRNAs) play vital regulatory roles in various biological processes, including in immune responses. Nile tilapia (Oreochromis niloticus) is an important commercial fish species in China. To identify immune-related miRNAs of O. niloticus, 4 libraries from liver during S. agalactiae infection (0 h, 5 h, 50 h, and 7 d) were sequenced by high-throughput sequencing technology in tilapia. We obtained 10,703,531, 11,507,163, 11,180,179 and 13,408,414 clean reads per library, respectively. In our results, a total of 482 miRNAs were identified through bioinformatic analysis, including 220 conserved miRNAs and 262 putative novel miRNAs. Moreover, 21 (4.36%), 50 (10.37%), and 46 (9.54%) miRNAs were significantly differentially expressed at 5 h, 50 h and 7 d, respectively. In addition, 6939 target genes regulated by these differentially expressed miRNAs were predicted, and their functional annotations were predicted by Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, which revealed that a majority of differentially expressed miRNAs were involved in apoptotic process, metabolic process, and immune responses. Finally, Real-time quantitative PCR experiments were performed for 7 miRNAs by stem-loop RT-PCR, and a general agreement was confirmed between the sequencing and RT-qPCR data. To our understanding, this is the first report of comprehensive identification of O. niloticus miRNAs being differentially regulated in liver related to S. agalactiae infection. This work provides an opportunity for further understanding of the molecular mechanisms of miRNA regulation in O. niloticus host-pathogen interactions, and genetic resources for molecular assistant selection for disease resistant breeding program.
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  • Identification and initial functional characterization of lysosomal integral membrane protein type 2 (LIMP-2) in turbot (Scophthalmus maximus L.)

    Tan, Fenghua   Cao, Min   Ge, Xuefeng   Li, Chao   Tian, Mengyu   Zhang, Lu   Fu, Qiang   Song, Lin   Yang, Ning  

    The immune system protects organism from external pathogens, this progress starts with the pathogen recognition by pattern recognition receptors (PRRs). As a group of PRRs, the class B scavenger receptors showed important roles in phagocytosis. Among three class B scavenger receptors, lysosomal integral membrane protein type 2 (LIMP-2) was reported to present in the limiting membranes of lysosomes and late endosomes, but its immune roles in teleost species are still limited in handful species. Here, we characterized LIMP-2 gene in turbot, and its expression patterns in mucosal barriers following different bacterial infection, as well as ligand binding activities to different microbial ligands and agglutination assay with different bacteria. In our results, one SmLIMP2 gene was identified with a 1,593 bp open reading frame (ORF). The multiple species comparison and phylogenetic analysis showed the closest relationship to Paralichthys olivaceus, the genomic structure analysis and syntenic analysis revealed the conservation of LIMP-2 during evolution. In tissue distribution analysis, SmLIMP-2 was expressed in all the examined turbot tissues, with the highest expression level in brain, and the lowest expression level in liver. In addition, SmLIMP-2 was significantly up-regulated in all the mucosal tissues (skin, gill and intestine) following Gram-negative bacteria Vibrio anguillarum infection, and was only up-regulated in gill following Gram-positive bacteria Streptococcus iniae challenge. Finally, the rSmLIMP-2 showed strong binding ability to all the examined microbial ligands, and strong agglutination with Escherichia colt Staphylococcus aureus and V. anguillarum. Taken together, our results suggested SmLIMP-2 played important roles in fish immune response to bacterial infection. However, further functional studies should be carried out to better characterize its detailed roles in teleost immunity.
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  • Expression profiling and functional characterization of galectin-3 of turbot (Scophthalmus maximus L.) in host mucosal immunity

    Tian, Mengyu   Yang, Ning   Zhang, Lu   Fu, Qiang   Tan, Fenghua   Li, Chao  

    Galectins, a family of evolutionary conserved beta-galactoside-binding proteins, have been characterized in a wide range of species. Galectin-3 is the only member in the chimera type, which is a monomeric lectin with one CRD domain. A growing body of evidence have indicated vital roles of galectin-3 in innate immune responses against infection. Here, one galectin-3 gene was captured in turbot (SmLgals3) with a 1203 bp open reading frame (ORF). In comparison to other species, SmLgals3 showed the highest similarity and identity to large yellow croaker and medaka, respectively. The genomic structure analysis showed that Sragals3 had 5 exons similar to other vertebrate species. The syntenic analysis revealed that galectin-3 had the same neighboring genes across all the selected species, which suggested the synteny encompassing galectin-3 region during vertebrate evolution. Subsequently, SmLgals3 was widely expressed in all the examined tissues, with the highest expression level in brain and the lowest expression level in skin. In addition, SmLgals3 was significantly down-regulated in intestine following both Gram-negative bacteria Vtbrio angdlIcrrum, and Gram-positive bacteria Streptococcus iniae immersion challenge. Finally, the rSmLgals3 showed strong binding ability to all the examined microbial ligands. Taken together, our results suggested SmLgals3 played vital roles in fish innate immune responses against infection. However, the knowledge of SmLgals3 are still limited in teleost species, further studies should be carried out to better characterize its detailed roles in teleost mucosal immunity.
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  • Characterization of a novel lncRNA (SETD3-OT) in turbot (Scophthalmus maximus L.)

    Yang, Ning   Wang, Beibei   Yu, Zhouxin   Liu, Xiaoli   Fu, Qiang   Cao, Min   Xue, Ting   Ren, Yichao   Tan, Fenghua   Li, Chao  

    LncRNAs have been demonstrated to play pivotal roles in virous biological processes, especially the gene expression regulation, including transcriptional regulation, posttranscriptional control and epigenetic processes. However, most of the current studies of lncRNAs are still limited in mammalian species, the investigations of functional roles of lncRNAs in teleost species are still lacking. In current study, we identified a novel lncRNA (SETD3-OT) in turbot, with 2,504 bp full-length obtained by 5' and 3' RACE, located in turbot chromosome 17, ranged from 20,933,835 to 20,936,302 bp. In addition, 8 neighboring genes of SETD3-OT were identified within 100 kbp in genome location. From the annotation of the neighboring adjacent genes, SETD3-OT might involve in regulation of cell apoptosis and cycle, the immune cell development, and the immune response against infection, and its expression pattern is similar to majority of the neighboring genes following Aeromonas salmonicida challenge. Intriguingly, SETD3-OT showed significant high expression levels in mucosal surfaces (intestine, gill and skin), and was dramatically down-regulated in these mucosal tissues following Vibrio anguillarum challenge, especially in gill and skin. In addition, SETD3-OT was distributed in nucleus, it might regulate the neighboring genes in cis or in trans. Taken together, our results provide insights for lncRNA in fish innate immunity, further studies should be conduct to explore the detailed molecular mechanism of the gene regulation between SETD3OT and its neighboring genes.
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  • A robust strategy of homogeneously hybridizing silica and Cu-3(BTC)(2) to in situ synthesize highly dispersed copper catalyst for furfural hydrogenation

    Yang, Xu   Liu, Wu   Tan, Fenghua   Zhang, Zhaoxia   Chen, Xindi   Liang, Tengda   Wu, Chuande  

    Catalyst deactivation caused by the metal sintering/leaching is still a great challenge confronted by the scientists. Herein, we report a robust strategy to in situ synthesize mesoporous silica supported highly dispersed copper catalyst by homogeneously hybridizing the silica and metal-organic framework (MOF) copper benzene-1,3,5-tricarboxylate (Cu-3(BTC)(2)). We find the introducing silica is the key to the formation of homogeneous hybridization by regulating the growth of Cu-BTC crystallite, yielding various metal dispersion and reducibility during calcination; while the added BTC ligands acts as porous initiator, promoting the accessibility of copper centers for reactants. The optimized CuO#SiO2-s1 with molar ratio Cu/Si of 0.23, exhibits excellent catalytic performance towards the furfural hydrogenation, showing a high activity as 9.2 mol(FF) mol(cu)(-1) h(-1), nearly 100 % furfural alcohol selectivity and minimized activity decline (< 5%) after 5 repeated run. This work could open up a new avenue for the synthesis of mesoporous silica supported highly dispersed metal catalyst for hydrogenation.
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  • Identification,characterization and expression analysis of TLR5 in the mucosal tissues of turbot (Scophthalmus maximus L.) following bacterial challenge

    Liu, Fengqiao   Su, Baofeng   Fu, Qiang   Shang, Mei   Gao, Chengbin   Tan, Fenghua   Li, Chao  

    TLRs (Toll-like receptors) are very important pathogen pattern recognition receptors, which control the host immune responses against pathogens through recognition of molecular patterns specific to microorganisms. In this regard, investigation of the turbot TLRs could help to understand the immune responses for pathogen recognition. Here, transcripts of two TLR5 (TLR5a and TLR5b) were captured, and their protein structures were also predicted. Meanwhile, we characterized their expression patterns with emphasis on mucosal barriers following different bacterial infection. The phylogenetic analysis revealed the turbot TLR5 genes showed the closest relationship to Paralichthys olivaceus. These two TLR5 genes were ubiquitously expressed in healthy tissues although expression levels varied among the tested tissues. In addition, the two copies of turbot TLR5 showed different expression patterns after bacterial infections. After Vibrio anguillarum infection, TLR5a was generally up-regulated in intestine and skin while down-regulated in gill, while TLR5b showed a general down-regulation in mucosal tissues. After Streptococcus iniae infection, the TLR5a was down-regulated at 2 h while generally up-regulated after 4 h in mucosal tissues. Interestingly, the TLR5b was up-regulated in intestine while down-regulated in skin and gill after Streptococcus iniae infection. These findings suggested a possible irreplaceable role of TLR5 in the immune responses to the infections of a broad range of pathogens that include Gram-negative and Gram-positive bacteria. Future studies should apply the bacteriological and immune-histochemical techniques to study the main sites on the mucosal tissue for bacteria entry and identify the ligand specificity of the turbot TLRs after challenge. (C) 2017 Elsevier Ltd. All rights reserved.
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  • Identification and expression analysis of toll-like receptor genes (TLR8 and TLR9) in mucosal tissues of turbot (Scophthalmus maximus L.) following bacterial challenge

    Dong, Xiaoyu   Su, Baofeng   Zhou, Shun   Shang, Mei   Yan, Hao   Liu, Fengqiao   Gao, Chengbin   Tan, Fenghua   Li, Chao  

    Mucosal immune system is one of the most important components in the innate immunity and constitutes the front line of host defense against infection, especially for teleost, which are living in the pathogen-rich aquatic environment. The pathogen recognition receptors (PRRs), which can recognize the conserved pathogen-associated molecular patterns (PAMPs) of bacteria, are considered as one of the most important component for pathogen recognition and immune signaling pathways activation in mucosal immunity. In this regard, we sought to identify TLR8 and TLR9 in turbot (Scophthalmus maximus), as well as their mucosal expression patterns following different bacterial infection in mucosal tissues for the first time. The full-length TLR8 transcript consists of an open reading frame (ORF) of 3108 bp encoding the putative peptide of 1035 amino acids. While the TLR9 was 6730 bp long, containing a 3168 bp ORF that encodes 1055 amino acids. The phylogenetic analysis revealed both TLR8 and TLR9 showed the closest relationship to large yellow croaker. Moreover, both TLR8 and TLR9 could be detected in all examined healthy turbot tissues, with the lowest expression level in liver and a relatively moderate expression pattern in healthy mucosal tissues. Distinct expression patterns of TLR8 and TLR9 were comparatively observed in the mucosal tissues (intestine, gill and sldn) following Vibrio anguillarum and Streptococcus iniae infection, suggesting their different roles for mucosal immunity. Further functional studies are needed to better characterize TLR8 and TLR9 and their family members, to better understand the ligand specificity and to identify their roles in different mucosal tissues in protecting fish from the pathogenically hostile environment. (C) 2016 Elsevier Ltd. All rights reserved.
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  • Characterization and initial functional analysis of cathepsin K in turbot (Scophthalmus maximus L.)

    Tian, Mengyu   Cao, Min   Zhang, Lu   Fu, Qiang   Yang, Ning   Tan, Fenghua   Song, Lin   Su, Baofeng   Li, Chao  

    Cathepsins are the best-known group of proteases in lysosomes, playing a significant role in immune responses. Cathepsin K (CTSK) is abundantly and selectively expressed in osteoclasts, dendritic cells and monocyte-derived macrophages, where it is involved in ECM degradation and bone remodeling. A growing body of evidences have indicated the vital roles of cathepsin K in innate immune responses. Here, one CTSK gene was captured in turbot (SmCTSK) with a 993 bp open reading frame (ORF). The genomic structure analysis showed that SmCTSK had 7 exons similar to other vertebrate species. The syntenic analysis revealed that CTSK had the same neighboring genes across all the selected species, which suggested the synteny encompassing CTSK region was conserved during vertebrate evolution. Subsequently, SmCTSK was widely expressed in all the examined tissues, with the highest expression level in spleen and the lowest expression level in liver. In addition, SmCTSK was significantly down-regulated in intestine following Gram-negative bacteria Vibrio anguillarum immersion challenge, but upregulated in three tissues (gill, skin and intestine) following Gram-positive bacteria Streptococcus iniae immersion challenge. Finally, the rSmCTSK showed strong binding ability to all the examined microbial ligands. Taken together, our results suggested SmCTSK played vital roles in fish innate immune responses against infection. However, the knowledge of SmCTSK is still limited in teleost species, further studies should be carried out to better characterize its comprehensive roles in teleost mucosal immunity.
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  • Identification and expression analysis of TLR2 in mucosal tissues of turbot (Scophthalmus maximus L.) following bacterial challenge

    Liu, Fengqiao   Su, Baofeng   Gao, Chengbin   Zhou, Shun   Song, Lin   Tan, Fenghua   Dong, Xiaoyu   Ren, Yichao   Li, Chao  

    The pathogen recognition receptors (PRRs), which can recognize the conserved pathogen-associated molecular patterns (PAMPs) of the bacteria, play key roles in the mucosal surfaces for pathogen recognition and activation of immune signaling pathways. However, our understanding of the PRRs and their activities in mucosal surfaces in the critical early time points during pathogen infection is still limited. Towards to this end, here, we sought to identify the Toll-like receptor 2 (TLR2) in turbot as well as its expression profiles in mucosal barriers following bacterial infection in the early time points. The fulllength TLR2 transcript consists of open reading frame (ORF) of 2451 bp encoding the putative peptide of 816 amino acids. The phylogenetic analysis revealed the turbot TLR2 showed the closest relationship to Paralichthys olivaceus. The TLR2 mRNA expression could be detected in all examined tissues, with the most abundant expression level in liver, and the lowest expression level in skin. In addition, TLR2 showed different expression patterns following Vibrio anguillarum and Streptococcus iniae infection, but was up regulated following both challenge, especially post S. iniae challenge. Characterization of TLR2 will probably contribute to understanding of a number of infectious diseases and broaden the knowledge of interactions between host and pathogen, which will eventually help in the development of novel intervention strategies for farming turbot. (C) 2016 Elsevier Ltd. All rights reserved.
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  • Mesoporous Carbon Shell Encapsulated Co/Co2P Composite for Electrocatalytic Hydrogen Evolution Reaction:The Effect of Cd Initiator on its Catalytic Performance

    Liang, Huagen   Yang, Chen   Jia, Linhui   Jiang, Ningyi   Tan, Fenghua   Wu, Liangpeng   Yang, Xu   Chen, Fu  

    Herein, a novel cadmium nitrite initiated mesoporous carbon shell encapsulated binary cobalt/cobalt phosphide (Co/Co2P@MC-(Cdx)) composites were first prepared by a facile solvothermal reaction following a phosphorization procedure. The Co/Co2P@MC-(Cd0.5), with molar ratio of Cd/Co =3D 0.5 in the initial feeding stock, exhibited overpotentials of as low as 99 mV at 10 mA cm(-2) and small Tafel slopes of 53 mV dec(-1) under 0.5 M H2SO4 conditions. Various techniques further demonstrated that the superior activity of Co/Co2P@MC-(Cd0.5) was attributed to the introduction of Cd initiator, which resulted in the mesoporisity on carbon shell and the modified electron state between the Co and Co2P. This novel Cd initiated mesoporous carbon encapsulated Co/Co2P composites hold promising potential for utilization in the hydrogen evolution from electrocatalytic water splitting. Graphic Abstract A novel cadmium nitrite initiated mesoporous carbon shell encapsulated binary cobalt/cobalt phosphide (Co/Co2P@MC-(Cdx)) composites were first prepared. The Co/Co2P@MC-(Cd0.5), with molar ratio of Cd/Co =3D 0.5 in the initial feeding stock, exhibited overpotentials of as low as 99 mV at 10 mA cm(-2) and small Tafel slopes of 53 mV dec(-1) under 0.5 M H2SO4 conditions. The superior activity of Co/Co2P@MC-(Cd0.5) was attributed to the introduction of Cd initiator, which resulted in the mesoporisity on carbon shell and the modified electron state between the Co and Co2P. [GRAPHICS] .
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  • Periodic solutions for second-order difference equations with resonance at infinity

    Tan, Fenghua   Guo, Zhiming  

    By using the critical point theory and a Z(p) geometrical index theory, some sufficient conditions are obtained for the existence and multiplicity of periodic solutions to the following non-linear second-order difference equation Delta(2) x(n-1) + f(x(n)) = 0, where f is an element of C(R, R) is resonant at infinity.
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  • Dynamics of MiRNA Transcriptome in Turbot (Scophthalmus maximus L.) Intestine Following Vibrio anguillarum Infection

    Gao, Chengbin   Cai, Xin   Fu, Qiang   Yang, Ning   Song, Lin   Su, Baofeng   Tan, Fenghua   Liu, Baining   Li, Chao  

    MicroRNAs (miRNAs) are a group of small non-coding RNAs, which could bind to the 3 '-untranslated regions of their target mRNAs to regulate gene expression in various biological processes, including immune-regulated signaling pathways. Turbot (Scophthalmus maximus L.), an important commercial fish species in China, has been suffering with Vibrio anguillarum infection resulted in dramatic economic loss. Therefore, we investigated the expression profiles of miRNAs, as well as the immune-related miRNA-mRNA pairs in turbot intestine at 1 h, 4 h, and 12 h following V. anguillarum infection. As a result, 266 predicted novel miRNAs and 283 conserved miRNAs belonging to 92 miRNA families were detected. A total of 44 miRNAs were differentially expressed in the intestine following V. anguillarum infection. Following prediction, the potential target genes of differentially expressed miRNAs were grouped into a wide range of functional categories, including immune defense/evasion, inflammatory responses, RIG-I signaling pathway, and Toll-like receptor signaling pathway. Moreover, we selected 15 differentially expressed immune genes and their related differentially expressed miRNAs to construct an interaction network for V. anguillarum infection in turbot. These results suggested that in teleost, as in higher vertebrates, miRNAs prominently contribute to immune responses, protecting the host against infection. In addition, this is the first report of comprehensive identification of turbot miRNAs being differentially regulated in the intestine related to V. anguillarum infection. Our results provided an opportunity for further understanding of the molecular mechanisms of miRNA regulation in turbot host-pathogen interactions.
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