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Now showing items 1 - 11 of 11

  • Draft genome of the Peruvian scallop Argopecten purpuratus.

    Li, Chao   Liu, Xiao   Liu, Bo   Ma, Bin   Liu, Fengqiao   Liu, Guilong   Shi, Qiong   Wang, Chunde  

    Background: The Peruvian scallop, Argopecten purpuratus, is mainly cultured in southern Chile and Peru was introduced into China in the last century. Unlike other Argopecten scallops, the Peruvian scallop normally has a long life span of up to 7 to 10 years. Therefore, researchers have been using it to develop hybrid vigor. Here, we performed whole genome sequencing, assembly, and gene annotation of the Peruvian scallop, with an important aim to develop genomic resources for genetic breeding in scallops.; Findings: A total of 463.19-Gb raw DNA reads were sequenced. A draft genome assembly of 724.78 Mb was generated (accounting for 81.87% of the estimated genome size of 885.29 Mb), with a contig N50 size of 80.11 kb and a scaffold N50 size of 1.02 Mb. Repeat sequences were calculated to reach 33.74% of the whole genome, and 26,256 protein-coding genes and 3,057 noncoding RNAs were predicted from the assembly.; Conclusions: We generated a high-quality draft genome assembly of the Peruvian scallop, which will provide a solid resource for further genetic breeding and for the analysis of the evolutionary history of this economically important scallop.=20
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  • Glacier Dynamics and Water Balance in the Qinghai-Tibet Plateau

    Zhang, Mi   Zhao, Yuping   Liu, Fengqiao   Pan, Xubin  

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  • Comment on "Productivity Is a Poor Predictor of Plant Species Richness"

    Pan, Xubin   Liu, Fengqiao   Zhang, Mi  

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  • Selection of a new scallop strain,the Bohai Red,from the hybrid between the bay scallop and the Peruvian scallop

    Wang, Chunde   Liu, Bo   Liu, Xiao   Ma, Bin   Zhao, Yuming   Zhao, Xia   Liu, Fengqiao   Liu, Guilong  

    In our previous studies, inter-specific hybrid F-1 with significant heterosis in growth was produced by hybridizing the bay scallop, Argopecten irradians irradians with the Peruvian scallop, A. purpuratus. However, due to the hermaphroditic nature of the two Argopecten scallops, it is difficult to produce the hybrid seed at large scales. To efficiently utilize the genetic resources of the two scallops, this study aimed to breed a new scallop strain from the hybrids. The key step in the selection was the breeding of the F-1 generation from the hybrid cohort, most of which were both male- and female-sterile. A small cohort of F-1 with normal male- and female-fertility was produced through mass spawning of a large cohort of hybrids. The F-2-F-6 cohorts were reproduced with size- and color-selected brood stocks from the F-1-F-5 cohort, respectively. The results showed that, compared with the control bay scallop cohorts, the average shell height, average whole body weight and average adductor muscle weight were increased by 15.6%, 37.9% and 40.7% in F1, by 14.7%, 33.9% and 43.6% in F-2, by 14.1%, 33.1% and 38.4% in F-3, by 11.7%, 38.8% and 49.3% in F-4, by 12.2%, 37.9% and 53.8% in F-5, by 18.5%, 42.6% and 75% in F-6, respectively. After six generations of selection, the median lethal temperature range was expanded from 3.0-29.0 degrees C in F-1 to 0 degrees C-29.1 degrees C in F-6, suggesting that the selected strain can be reared in most waters of China, especially in Bohai Sea and Yellow Sea. Thus, through continuous selection on size and color, we have obtained a superior strain from the hybrids between the bay scallop and the Peruvian scallop, which is named 'Bohai Red'.
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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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  • 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  

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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, 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  

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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 expression analysis of a peptidoglycan recognition protein gene,SmPGRP2 in mucosal tissues of turbot (Scophthalmus maximus L.) following bacterial challenge

    Zhang, Linan   Gao, Chengbin   Liu, Fengqiao   Song, Lin   Su, Baofeng   Li, Chao  

    Peptidoglycan recognition receptor proteins (PGRPs), a group of pattern recognition receptors (PRRs), can recognize peptidoglycan (PGN) of the bacteria cell wall and play an important role in host immune defense against pathogen infection. They are highly structurally conserved through evolution, but with different function in innate immunity between invertebrates and vertebrates. In teleost fish, several PGRPs have been characterized recently. They have both amidase activity and bactericidal activity and are involved in indirectly killing bacteria and regulating multiple signaling pathways. However, the knowledge of PGRPs in mucosal immunity of teleost fish is still limited. In this study, we identified a PGRPs gene (SmPGRP2) of turbot and investigated its expression patterns in mucosal tissues after challenge with Gram-positive bacteria Streptococcus iniae and Gram-negative bacteria Vibrio anguillarum. Phylogenetic analysis showed the strongest relationship of turbot PGRP to halibut, which was consistent with their phylogenetic relationships. In addition, SmPGRP2 was ubiquitously expressed in turbot tissues, and constitutive expression levels were higher in classical immune tissues (including liver, spleen, and head-kidney) than mucosal tissues (intestine, gill and skin). After bacterial challenge, the expression of SmPGRP2 was induced and showed a general trend of up-regulation in mucosal tissues, except in intestine following V. anguillarum infection. These different expression patterns varied depending on both pathogen and tissue type, suggesting its distinct roles in the host immune response to bacterial pathogen. (C) 2016 Elsevier Ltd. All rights reserved.
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  • SG-II solid state laser ICF system

    Fan, Dianyuan   Wang, Shiji   Lin, Zunqi   Gu, Yuan   Zhu, Jianqiang   Zhen, Yuxia   Zhu, Jian   Liu, Fengqiao   Chen, Shaohe   Chen, Qinghao   Huang, Guanlong  

    "The 8 beam SG-II laser facility with beam size of 245 mm is reported. Single-longitudinal mode oscillator including the temporal-spatial-transform pulse shaping; and a switch free coaxial double pass disk amplifier technology will be described. CCD beam quality diagnostic system is discussed. The two-beam co-line focus and two series coupling targets are in x-ray experiment is also introduced. The goal of the facility is to produce total pulse energy of 2.4 KJ at tripling frequency."
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