Publications by authors named "Mei-Qin Zhuo"

Information on transgenerational effects of cadmium (Cd) and zinc (Zn) within hour of exposure is scarce. To the end, larvae of marine medaka Oryzias melastigma at 0 day-post-hatching (dph) were subjected to LC for 96-h of Cd or Zn for 0.5 and 6 h, and then transferred into clear water for 95 days until the generation of offspring larvae at 25 dph.

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In this study, the transcriptional regulation of PI3KC3 by three transcription factors (PPARγ, PPARα, and STAT3) and the potential role of PI3KC3 in mediating lipid accumulation were determined in yellow catfish Pelteobagrus fulvidraco. The 5'-deletion assay, overexpression assay, site-mutation assay, and electrophoretic mobility shift assay suggested that PPARα, PPARγ, and STAT3 negatively regulated the promoter activity of pi3kc3. Moreover, the transcriptional inactivation of pi3kc3 was directly mediated by PPARα and PPARγ under fatty acid (FA) treatment.

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In the present study, two new SLC34 family members, named slc34a1b and slc34a2a, were isolated and characterized from grass carp Ctenopharyngodon idella. Topology, tissue distribution, and transcriptional response to phosphorus (Pi) and pH were compared among three members of SLC34 family (slc34a1b, slc34a2a, and slc34a2b) in grass carp. The length of validated cDNAs of grass carp slc34a1b and slc34a2a was 1494 bp and 1902 bp, and these two cDNAs encoded 497 and 633 amino acid residues, respectively.

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The present study was performed to clone and characterize the structures and functions of steroidogenic factor 1 (sf-1) and 17α-hydroxylase/lyase (cyp17α) promoters in yellow catfish , a widely distributed freshwater teleost. We successfully obtained 1981 and 2034 bp sequences of sf-1 and cyp17α promoters, and predicted the putative binding sites of several transcription factors, such as Peroxisome proliferator-activated receptor alpha (PPARα), Peroxisome proliferator-activated receptor gamma (PPARγ) and Signal transducer and activator of transcription 3 (STAT3), on sf-1 and cyp17α promoter regions, respectively. Overexpression of PPARγ significantly increased the activities of sf-1 and cyp17α promoters, but overexpression of PPARα significantly decreased the promoter activities of sf-1 and cyp17α.

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It is important to explore the regulatory mechanism of phosphorus homeostasis in fish, which help avoid the risk of P toxicity and prevent P pollution in aquatic environment. The present study obtained the full-length cDNA sequences and the promoters of three SLC20 members (, and ) from grass carp , and explored their responses to inorganic phosphorus (Pi). Grass carp SLC20s proteins possessed conservative domains and amino acid sites relevant with phosphorus transport.

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Early molecular events after the exposure of heavy metals, such as aberrant DNA methylation, suggest that DNA methylation was important in regulating physiological processes for animals and accordingly could be used as environmental biomarkers. In the present study, we found that copper (Cu) exposure increased lipid content and induced the DNA hypermethylation at the whole genome level. Especially, Cu induced hypermethylation of glucose-regulated protein 78 (grp78) and peroxisome proliferator-activated receptor gamma coactivator-1α (pgc1α).

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Excessive fat deposition in the hepatocytes, associated with excess dietary fat intake, was related to the occurrence of fatty livers in fish. miR-101b plays the important roles in controlling lipid metabolism, but the underlying mechanism at the post-transcriptional level remains unclear. The purpose of this study is to explore the roles and mechanism of miR-101b-mediating lipid deposition and metabolism in yellow catfish .

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The present study was conducted to explore the mechanism of nano-Zn absorption and its influence on lipid metabolism in the intestine of yellow catfish . Compared to ZnSO, dietary nano-Zn addition increased the triglyceride (TG) content, enzymatic activities of malic enzyme (ME) and fatty acid synthase (FAS), and up-regulated mRNA levels of , , , , , and . Using primary intestinal epithelial cells of yellow catfish, compared to the ZnSO group, nano-Zn incubation increased the contents of TG and free fatty acids (FFA), the activities of glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6GPD), ME, and FAS, up-regulated mRNA levels of lipogenic genes (, , , , and ), genes of lipid transport ( and ), and Zn transport genes ( and ), and increased the protein expression of fatty acid transport protein 4 (FATP4) and peroxisome proliferator activated receptor gamma (PPARγ).

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We characterized the promoters of target genes of the signal transducer and activator of transcription 3, STAT3 (carnitine palmitoyltransferase I, , acetyl-CoA carboxylase alpha, ; fatty acid synthase, ; and peroxisome proliferator-activated receptor gamma, ) in a teleost . Binding sites of STAT3 were predicted on these promoters, indicating that STAT3 probably mediated their transcriptional activities. Leptin had no effect on the activity of and promoters, but increased promoter activity and decreased promoter activity.

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In the present study, the length of 360, 1848 and 367 bp sequences of promoters from three subtypes of PI3K family (PI3KCa, PI3KC2b and PI3KC3) of yellow catfish were cloned and characterized. Bioinformatics analysis revealed that , and had different structures in their core promoter regions. The promoter regions of and had CpG islands but no CAAT and TATA box.

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The present working hypothesis is that absorption of dietary Cu is related to mRNA expressions of genes involved in Cu uptake and transport of the intestine in fish. To this end, the full-length cDNA sequences of eight Cu uptake related genes, including two isoforms of copper transporter genes (ctr1 and ctr2), three copper chaperone genes (atox1, ccs and cox17), two Cu-ATPase genes (atp7a and atp7b) and divalent metal ion transporter 1 (dmt1), were cloned and characterized in yellow catfish P. fulvidraco, respectively.

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In the present study, seven phosphoinositide 3-kinase (PI3K) members (PI3KCa, PI3KCb, PI3KCd, PI3KCg, PI3KC2a, PI3KC2b and PI3KC3, respectively) were isolated and characterized from yellow catfish Pelteobagrus fulvidraco, and their roles in insulin-induced changes of protein metabolism were determined. These seven PI3Ks can be divided into three classes, class I (including PI3KCa, PI3KCb, PI3KCd and PI3KCg), class II (including PI3KC2a and PI3KC2b) and class III (only including PI3KC3). Compared with mammals, all of these members share similar domain structure.

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In the present study, four AKT isoforms termed AKT1, AKT2, AKT3a and AKT3b were isolated and characterized from yellow catfish. Their molecular characterizations, tissue expressions and transcriptional responses to insulin and/or wortmannin were determined. The validated complementary DNA (cDNA) of yellow catfish AKT1, AKT2, AKT3a and AKT3b were 1422, 1431, 1389 and 1440 bp in length, encoding the peptide of 472, 475, 462 and 479 amino acid residues, respectively.

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The insulin receptor substrate (IRS) proteins, in particular, IRS1 and IRS2, are the key downstream players of insulin signaling pathway and the regulation of lipid metabolism. In the present study, two genes of IRS (IRS1 and IRS2) were isolated and characterized from yellow catfish Pelteobagrus fulvidraco. Their molecular characterizations, tissue expressions, and transcriptional levels by insulin both in vivo and in vitro were determined.

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Signal transducers and activators of transcription proteins (STATs) act as important mediators in multiple biological processes induced by a large number of cytokines. In the present study, full-length cDNA sequences of seven STAT members, including some splicing variants different from those in mammals, were obtained from Synechogobius hasta. The phylogenetic analysis revealed that the seven STAT members were derived from paralogous genes that might have arisen by whole genome duplication (WGD) events during vertebrate evolution.

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Liver X Receptor (LXR) plays a pivotal role in metabolic regulation in mammals, but little is known about its function in fish. In this study, two lxra isoforms, namely lxra1 and lxra2, were isolated. Their molecular characterization, tissues distribution and transcriptional regulation by insulin in vivo and in vitro were determined.

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Article Synopsis
  • - The study investigates how insulin affects lipid metabolism in yellow catfish (Pelteobagrus fulvidraco), focusing on hepatic lipid accumulation and the activity of key enzymes and transcription factors involved in this process.
  • - Insulin seems to boost liver lipid levels and increase lipogenic enzyme activity, particularly affecting mRNA levels of PPARα and PPARγ, while also showing that specific activators and inhibitors can modulate these insulin effects via different signaling pathways.
  • - The findings enhance our understanding of insulin's role in fish hepatic metabolism, highlighting the involvement of PPARα and PPARγ pathways in regulating lipid accumulation influenced by insulin.
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The present study was conducted to determine the effect of waterborne copper (Cu) exposure on carnitine concentration, carnitine palmitoyltransferases I (CPT I) kinetics, and expression levels of four CPT I isoforms in the liver, muscle and heart of yellow catfish Pelteobagrus fulvidraco. Yellow catfish were exposed to four waterborne copper (Cu) concentrations (2 (control), 24 (low), 71 (medium), 198 (high) μg Cu/l, respectively) for 6weeks. Waterborne Cu exposure increased maximal reaction rates (Vmax) in the liver and muscle, but not in the heart.

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The present study was conducted to determine the effect of leptin on lipid metabolism in ovarian follicle cells of yellow catfish Pelteobagrus fulvidraco. For that purpose, primary ovarian follicle cells were isolated from yellow catfish, cultured and subjected to different treatments (control, 0.1% DMSO, 500ng/ml leptin, 500ng/ml leptin plus 100μM wortmannin, 500ng/ml leptin plus 50nM AG490, respectively) for 48h.

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The present study was conducted to investigate the effects and mechanisms of hypothyroidism, induced by administration of 0.2% methimazole through the food, on lipid metabolism in the liver of juvenile yellow catfish Pelteobagrus fulvidraco. To this end, yellow catfish were fed diets containing either 0 or 2g methimazole per kg of diet for 8weeks, respectively.

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The present study was conducted to investigate the effects and mechanism of dietary Cu deficiency and excess on lipid metabolism in the liver, muscle and VAT of juvenile Pelteobagrus fulvidraco. To this end, yellow catfish were fed 0.76 (Cu deficiency), 4.

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Peroxisome proliferator-activated receptor alpha1 (PPARα1) cDNA was isolated from liver of yellow catfish Pelteobagrus fulvidraco by RT-PCR and RACE. Its molecular characterization, tissue expression and transcriptional regulation by insulin in vitro and in vivo were determined. PPARα1 mRNA covered 1879 bp, with an open reading frame (ORF) of 1410 bp encoding 469 amino acid residues, a 5'-untranslated region (UTR) of 49 bp, and a 3'-UTR of 421 bp.

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The present study was conducted to investigate the effects and mechanism of leptin influencing lipid metabolism in yellow catfish Pelteobagrus fulvidraco. To this end, hepatic lipid (in vivo experiment) and intracellular triglyceride (TG) (in vitro experiment) content, the activities and/or expression level of several enzymes (CPT-1, 6PGD, G6PD, FAS, ME and ICDH) as well as the mRNA expression of transcription factors (PPARα, PPARγ and SREBP-1) involved in lipid metabolism were determined. Using the primary hepatocytes of yellow catfish, specific inhibitors AG490 (JAK-STAT inhibitor) and wortmannin (IRS-PI3K inhibitor) were used to explore the signaling pathways of leptin effects on lipid metabolism.

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Peroxisome proliferator-activated receptor gamma (PPARγ) is ligand-inducible transcription factor and has important roles in lipid metabolism, cell proliferation and inflammation. In the present study, yellow catfish Pelteobagrus fulvidraco PPARγ cDNA was isolated from liver by RT-PCR and RACE, and its molecular characterization and transcriptional regulation by insulin in vivo and in vitro were determined. The generation of PPARγ1 and PPARγ2 was due to alternative promoter of PPARγ gene.

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Although the metabolic actions of insulin in fish have been investigated widely in the past years, the regulatory effect of insulin on lipid metabolism has received little attention, especially in primary hepatocytes of fish. In the present study, freshly hepatocytes were isolated from yellow catfish, cultured and subjected to different insulin levels (0, 10, 100 and 1000nM) for 0h, 24h and 48h. Triglyceride (TG) content, activity and expression of several key enzymes involved in lipid metabolism, as well as mRNA levels of key transcription factors related to lipid metabolism, were assessed at 0h, 24h and 48h, respectively.

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