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Xu H.,National University of Singapore | Xu H.,Pearl River Fishery Research Institute | Li C.,National University of Singapore | Li Y.,National University of Singapore | And 5 more authors.
Marine Biotechnology

Both dioxins/dioxin-like compounds and polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants and cause multiple adverse health effects on human and wildlife. Cyp1a is the most commonly used biomarker induced by these pollutants through activation of the aryl hydrocarbon receptor (AhR) pathway. Here we generated Tg(cyp1a:gfp) transgenic zebrafish for establishing a convenient in vivo assay for analysing these xenobiotic compounds. The Tg(cyp1a:gfp) larvae at 4 day post-fertilization were tested with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and GFP induction was observed mainly in the kidney, liver and gut. Similar GFP expression was also induced strongly by two dioxin-like chemicals, co-planar polychlorinated biphenyl (PCB126) and polychlorinated dibenzo-p-furan (PeCDF) and relatively weakly by two PAHs, 3-methylcholanthrene (3-MC) and benzo[a]pyrene (BAP). The lowest observed effective concentration (LOEC) of TCDD was estimated to be ∼1 pM and the EC50 (effective concentration to induce GFP in 50 % of Tg(cyp1a:gfp) larvae) was ∼10 pM. PCB126 and PeCDF had ∼10× lower potencies in GFP induction than TCDD, while the potencies for 3-MC and BAP were at least 1000× lower. The sensitivity of Tg(cyp1a:gfp) larvae to respond TCDD was also favourable compared to that of ethoxyresorufin-O-deethylase (EROD) assay in both zebrafish larvae and adult livers. As GFP-based assay in transgenic zebrafish can be easily accommodated in multi-well dishes, the Tg(cyp1a:gfp) zebrafish should provide not only a valuable biomonitoring tool for aquatic contaminants but also a potential high-throughput chemical screening platform for identification of new AhR agonists. © 2015, Springer Science+Business Media New York. Source

Shi Y.,Pearl River Fishery Research Institute | Zhu X.P.,Pearl River Fishery Research Institute | Zhu X.P.,Guangzhou University | Yin J.K.,Pearl River Fishery Research Institute | And 2 more authors.
Molecular Biology Reports

Interferon-regulatory factor 1 (IRF-1) is the first member of IRF family, which is involved in many biological processes such as immune response, antiviral defense, cell growth regulation, and apoptosis. In this study, an IRF-1 gene, EcIRF-1, was isolated and characterized from orange-spotted grouper (Epinephelus coioides). The full-length cDNA of EcIRF-1 is 1,730 bp, including an open reading frame of 906 bp, a 50-terminal untranslated region (50-UTR) of 153 bp, and a 30-UTR of 671 bp. The EcIRF-1 gene consists of 10 exons and 9 introns, spanning over approximate 4.3 kb of genomic sequence. The 50-UTR sequence contains an exon and an intron, and the 30-UTR sequence is included in the last exon. Expression analysis by real-time PCR reveals that the EcIRF-1 gene is ubiquitously expressed in various healthy fish tissues, whereas its expression is upregulated in vivo in response to polyinosinic-polycytidylic acid or lipopolysaccharide stimulation. Subcellular localization analysis shows the EcIRF-1 is an intranuclearly localized and immobile protein in the cultured fish cells. Data presented in this paper provide an important base to further understand EcIRF-1 gene function and its regulation associated with interferon immune system in orange-spotted grouper. © Springer Science+Business Media B.V. 2009. Source

Shi Y.,Pearl River Fishery Research Institute | Zhao Z.,CAS South China Sea Institute of Oceanology | Yin J.-K.,Pearl River Fishery Research Institute | Zhu X.-P.,Pearl River Fishery Research Institute | And 4 more authors.
Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology

Interferon regulatory factor 2 (IRF-2) is a multifunctional transcription factor which exhibits both transcriptional activating and repressing activities in the IRF family. In this study, we report an IRF-2 gene isolated from orange-spotted grouper (Epinephelus coioides). The 1854 bp full-length cDNA sequence of EcIRF-2 has been cloned, encoding a putative peptide of 336 amino acids which is highly consistent with the feature of IRF family members. The genomic fragment of EcIRF-2 contains nine exons and eight introns, spanning over approximate 8.8 kb. The expression of EcIRF-2 gene was detected in various tissues of healthy orange-spotted grouper and in four tissues after being challenged with poly I:C or LPS. EcIRF-2 gene is ubiquitously expressed in various healthy fish tissues and is up-regulated in vivo in response to poly I:C or LPS. Subcellular localization analysis of EcIRF-2 suggests it is an intranuclear protein in the fish cells. We believe this research is the first report of fish IRF-2 protein localization. The results in this research establish the base for further study of function mechanism of IRF family members in orange-spotted grouper. © 2009 Elsevier Inc. All rights reserved. Source

Ye X.,Pearl River Fishery Research Institute | Li J.,Pearl River Fishery Research Institute | Li J.,Shanghai Ocean University | Lu M.,Pearl River Fishery Research Institute | And 5 more authors.
Fisheries Science

Bacteria strains with strong virulence were isolated from pond-cultured tilapia in China. They were identified as Streptococcus agalactiae by biochemical assays, and confirmed by 16S ribosomal RNA (rRNA) and group B Streptococcus (GBS)-specific gene cfb analyses. Multiplex polymerase chain reaction (PCR) assay of the alpha C protein (ACP) gene and capsular polysaccharide antigen (cps) gene was employed to identify their molecular serotype (MS). Amplification of the ACP gene produced a 400-bp C alpha protein gene (bca) fragment, suggesting that these isolates belong to MS Ia, Ib or II; amplification of cps produced a 790-bp amplicon, indicating that they belong to MS Ia/III-3. An additional PCR based on nucleotide difference in the cps H-I region of MS Ia and III further suggested that the isolates belong to serotype MS Ia. Moreover, multi-locus sequence typing (MLST) indicated that these strains were of sequence type 7 (ST-7). These results showed that isolates from different regions of China shared the same MS and ST. However, none of the isolated ST-7 GBS corresponded to the capsular serotype, suggesting that these fish GBS possessed specific molecular characteristics not present in human or other animals. Data from this study will facilitate the understanding of epidemiology and nosogenesis of tilapia GBS and the establishment of effective disease prevention methods. © 2011 The Japanese Society of Fisheries Science. Source

Tan X.,Pearl River Fishery Research Institute | Kang M.,Myriax Software Pty Ltd | Tao J.,Chinese Academy of Sciences | Li X.,Pearl River Fishery Research Institute | Huang D.,Chinese Academy of Sciences
Fisheries Science

Hydroacoustic surveys were conducted to understand the relationship between fish density, spatial distribution, and behavior upstream and downstream of the Changzhou Dam on the Pearl River, China, and the condition (open/closed) of the spillways. When the spillways were open on 24 June 2010, numerous fish were observed to be densely distributed in the forebay upstream of the dam, with an average fish density was 0.22 fish m-3. When the spillways were closed on 25 June 2010, the fish upstream of the dam dispersed, and the average fish density decreased to 0.007 fish m-3. Prior to operating the spillways on 24 May 2010, the average fish density downstream of the dam was 0.28 fish m-3; in comparison, on 26 June, immediately following closure of the spillways, the average fish density downstream of the dam was 0. 08 fish m-3. Fish were more active on June 24 than on 25 June: they swam faster and their positions in the water column varied greatly. On 26 June, fish did not to swim as freely in the water column as those measured on 24 May. Based on these observations, we conclude that a large number of fish are able to swim to the upstream side of the dam while the spillways are open. © 2011 The Japanese Society of Fisheries Science. Source

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