Li Xiong

Southwest University, Kenner, Louisiana, United States

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Publications (4)1.68 Total impact

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    ABSTRACT: Heat-shock protein 90 (HSP90) is an abundant and highly conserved molecular chaperone, and it fulfills a housekeeping function in contributing to the folding, maintenance of structural integrity, and proper regulation of a subset of cytosolic proteins. In this study, the full-length 2693-bp cDNA of HSP90 was cloned by rapid amplification of cDNA ends (RACE) technique from the liver of rare minnow (Gobiocypris rarus) for the first time, designated as GrHSP90. The complete coding sequence of GrHSP90 is 2181 bp in length, which encodes a polypeptide of 726 amino acids with a predicted molecular mass of 83.4 kDa and a theoretical isoelectric point of 4.90. Phylogenetic tree analysis indicated that deduced protein GrHSP90 had extensive sequence similarities to other fish HSP90s. Tissue distribution showed that GrHSP90 was constitutively expressed in a wide range of tissues including gill, blood, brain, fin, gonad, heart, intestine, kidney, liver, muscle, spleen, skin, and swim bladder. The highest expression was found in the gonad. Furthermore, significant increase in GrHSP90 mRNA in the liver was observed after exposure to pentachlorophenol ≥8 µg/L (p < 0.05). Our results suggest that GrHSP90 is indeed an ortholog of the HSP90 family and may be act as a biomarker to assess the effect of environmental contaminant.
    Fish Physiology and Biochemistry 06/2015; DOI:10.1007/s10695-015-0085-2 · 1.68 Impact Factor
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    ABSTRACT: 3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) is the first rate-limiting enzyme in the mevalonate (MVA) pathway. The full-length cDNA of HMGR was cloned from Gobiocypris rarus, and HMGR expression profiles in different tissues and in response to different treatments of pentachlorophenol (PCP) were analyzed by real-time PCR, to investigate the endocrine disruption mechanism of PCP, which altered steroid hormone precursors (cholesterol) levels by modulating gene transcription profiles of HMGR. Based on the homologous clone strategy and rapid-amplification of cDNA ends (RACE) technology, the full-length 3 101-base-pair (bp) cDNA of HMGR was isolated from the livers of rare minnow (Gobiocypris rarus) for the first time, and was designated as GrHMGR (GenBank accession number KF885724). GrHMGR encoded a protein of 884 amino acids and phylogenetic tree analysis indicated that the deduced protein GrHMGR had extensive sequence similarities to other fish HMGRs. Real-time PCR analyses indicated that GrHMGR mRNA expression was tightly controlled in a tissue-specific fashion, with the sites of expression being brain, gonads and liver, and the highest site of expression being gonads. After male rare minnows were exposed to different concentrations of PCP, significant decrease in GrHMGR gene expression with increased PCP concentration in the brain and gonads were observed, together with the differential gene expression trend in the liver. Furthermore, it was found that the decrease of HMGR could reduce the synthesis of cholesterol. This proved that PCP might disrupt the pathway of cholesterol synthesis and then influenced the endocrine system of rare minnow.
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    ABSTRACT: Pentachlorophenol (PCP), a typical organic pollutant and environmental endocrine disruptor, has been extensively used as a pesticide and biocide worldwide. In this study, the effects of PCP on the histological and hepatic system of the rare minnow (Gobiocypris rarus) were evaluated. Vitellogenin (VTG) was used as a biomarker to evaluate the estrogen effect of PCP. The results revealed that VTG was highly expressed and PCP exposure had histopathological effects on the rare minnow. Plasma and hepatic VTG concentrations increased when female rare minnows were exposed to ≥80 μg/L PCP and male rare minnows were exposed to 40 μg/L PCP (p < 0.05), which suggested that the VTG expression was evoked by PCP exposure. The results indicated that both plasma and liver tissue were suitable for VTG quantification. A significant decrease in the mRNA level of hepatic estrogen receptor-α (ERα) in male or juvenile was observed after exposure to ≥80 or ≥8 μg/L PCP, respectively; in contrast, increased mRNA levels of ERβ1, ERβ2, VTGI, and VTGII in male or juvenile were detected after exposure to ≥80 or ≥8 μg/L PCP, respectively. These results suggested that PCP has an estrogen effect and exists within different endocrine-disrupting pathways from other environmental contaminants. As such, VTG mRNA expression in the rare minnow may require transcription of the ERβ1 and ERβ2 genes.
    Fish Physiology and Biochemistry 11/2013; 40(3). DOI:10.1007/s10695-013-9887-2 · 1.68 Impact Factor
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    ABSTRACT: Taking the Chinese rare minnow (Gobiocypris rarus) as the test animal, the studies were designed to investigate induction effects of pentachlorophenol (PCP) on vitellogenin (VTG) protein, VTG gene and tumor suppressor p53 gene in the liver of Gobiocypris rarus. The endocrine disrupting of PCP was evaluated by detecting VTG, and sensitive biomarkers of PCP were screened at both protein and mRNA levels. Gobiocypris rarus were exposed to PCP at 1.5, 15, 40, 80, 120, 150, 160 microg x L(-1) respectively, while setting blank, solvent control and 17alpha-ethynylestradiol (EE2) as positive control. Using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), enzyme-linked immunosorbent assay (ELISA), VTG protein expression differences were detected in the liver of Gobiocypris rarus after exposure to PCP. Cloning the VTG and p53 gene new fragments of Gobiocypris rarus based on conserved regions, mRNA expression levels of VTG and p53 gene in the liver of Gobiocypris rarus were determined by quantitative real-time PCR assay after PCP treatment. The results showed that 40, 80, 120, 160 microg x L(-1) PCP induced the liver of male and female Gobiocypris rarus to produce VTG protein, and had a significant concentration effect. VTG and p53 mRNA levels significantly increased in the liver of Gobiocypris rarus after exposure to 1.5, 15, 150 microg x L(-1) PCP, and had remarkable concentration and time effects. The studies suggested that PCP had estrogenic effects, and VTG protein, VTG and p53 gene in the liver of Gobiocypris rarus could be used as candidate sensitive biomarkers for detecting PCP.
    Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 06/2012; 33(6):1858-64.
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    ABSTRACT: Using human cervical carcinoma HeLa cells, the cell viability was determined by MTT assay after pentachlorophenol (PCP) treatment, the cytotoxicity of PCP was evaluated by detecting lactate dehydrogenase (LDH) leakage rate and total superoxide dismutase (SOD) activity in cell culture medium; DNA damage was detected by comet assay. The results indicated that HeLa cells proliferation was inhibited by PCP and the median inhibitory concentration (IC50) was 66.59 micromol x L(-1); PCP did not induce DNA damage in the concentration range from 6.25 micromol x L(-1) to 50 micromol L(-1); LDH leakage rate increased gradually with the increasing of exposure time when HeLa cells were treated by PCP in the concentration range from 12.5 micromol x L(-1) to 200 micromol x L(-1); SOD activity decreased gradually as the increasing of exposure time when HeLa cells were treated by PCP at lower concentration of 12.25 micromol x L(-1), 17.5 micromol x L(-1), 25 micromol x L(-1) respectively, LDH leakage rate increased significantly at 25 micromol x L(-1) and activity of SOD decreased markedly at 12.25 micromol x L(-1) in HeLa cells following PCP-treatment respectively. Results suggested that SOD and LDH might be regarded as candidate sensitive biomarkers for evaluating toxicity of PCP at low concentration on human and wildlife.
    Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 02/2012; 33(2):658-64.

Publication Stats

1 Citation
1.68 Total Impact Points

Institutions

  • 2013
    • Southwest University
      Kenner, Louisiana, United States
  • 2012
    • Southwest University in Chongqing
      Pehpei, Chongqing Shi, China