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Shi Y.,Sun Yat Sen University | Shi Y.,CAS South China Sea Institute of Oceanology | Liu X.,Sun Yat Sen University | Zhang H.,Guangdong Daya Bay Fishery Development Center | And 4 more authors.
Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology | Year: 2012

Androgens play a crucial role in sex differentiation, sexual maturation, and spermatogenesis in vertebrates. The action of androgens is mediated via androgen receptors (ARs). The present study reports the cloning of the cDNA sequence of the ar in the orange-spotted grouper, with high expression in testis and relatively low in subdivision of brain areas. The cDNA sequence of ar was 2358. bp, encoding a protein of 759 amino acids (aa). Phylogenetic analysis showed that the ar cDNA sequence was closely related to that of threespot wrasse (Halichoeres trimaculatus) and medaka (Oryzias latipes) arβ. As deduced from the phylogenetic tree and the high amino acid identity with the ARβ subtype of other teleosts, grouper ar seems to be more closely related to the beta than the alpha subtype cloned to date. In the first week after 17α-methyltestosterone (MT) implantation, the transcript levels of ar in the hypothalamus declined significantly, and consistently stayed at low level expression to the second week, but increased back to the control levels in the third and fourth week. In the gonad, the mRNA expression of ar was not changed in the first week compared with the control, but increased significantly in the second week, consistently reached the highest level in the third week, dropped slightly but still higher than that of the control in the fourth week. The expression pattern of ar in hypothalamus and gonad during MT-induced sex reversal suggests the involvement of ar in regulating this process in the orange-spotted grouper. The present study provides the data of the changes in the mRNA levels of ar during MT-induced sex reversal in detail to help understand the complicated signals under sex reversal. © 2012 Elsevier Inc. Source


Hu X.,Sun Yat Sen University | Hu X.,Chinese Academy of Fishery Sciences | Liu X.,Sun Yat Sen University | Zhang H.,Guangdong Daya Bay Fishery Development Center | And 10 more authors.
Molecular Reproduction and Development | Year: 2011

It is known that the hypothalamic-pituitary-gonadal axis participates in the sex change of hermaphrodite teleosts, and gonadal steroid hormones mediate this physiological process. The secretion of gonadal steroids is directly regulated by signaling pathways involving gonadotropins (GtHs) and gonadotropin receptors (GtHRs) in teleosts. To gain insight into the involvement of GtH/GtHR systems in the sex change process, cDNAs encoding follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) were firstly isolated from gonads of orange-spotted grouper (Epinephelus coioides), a protogynous hermaphrodite fish. Reverse transcription-PCR (RT-PCR) analysis demonstrated that the expression of the FSHR was confined to the brain, pituitary gland, ovary, and testis, while the LHR was expressed only in the brain, ovary, and testis. Furthermore, the expression profiles of GtH subunits (FSHβ and LHβ) and their receptors were analyzed in parallel with the serum levels of estradiol-17β (E 2), testosterone (T), and 11-ketotestosterone (11-KT) during 17α-methyltestosterone (MT)-induced sex change. Quantitative real-time PCR determined that the abundances of FSHβ and FSHR were significantly inhibited after MT treatment for 2 and 4 weeks, but subsequently returned to the control level after 6 weeks. In contrast, the mRNA levels of LHβ and LHR were significantly elevated throughout the sex change process. During MT-induced sex change, serum concentrations of E 2 remained constant while T and 11-KT levels were significantly increased. Taken together, our results suggest that GtH/GtHR systems are involved in MT-induced sex change, and two signaling pathways may have distinct roles in modulating the variations of the corresponding steroid hormones in the orange-spotted grouper. © 2011 Wiley-Liss, Inc. Source


You X.,Sun Yat Sen University | You X.,Marine and Fisheries Institute | You X.,State Key Laboratory of Agricultural Genomics | Shu L.,State Key Laboratory of Agricultural Genomics | And 19 more authors.
BMC Genetics | Year: 2013

Background: Orange-spotted grouper, Epinephelus coioides, is one of the most valuable fish species in China. Commercial production of orange-spotted grouper could be increased by developing higher growth rates and improving commercially important traits. Information on genetic markers associated with quantitative trait loci (QTL) can be used in breeding programs to identify and select individuals carrying desired traits. A high-density genetic linkage map is the basis for QTL study, and multiplexed shotgun genotyping (MSG) facilitates the development of single nucleotide polymorphisms (SNPs) and genotyping. In this study, the first high-density genetic linkage maps for groupers were generated on the basis of the MSG method.Results: The sex-averaged map contained a total of 4,608 SNPs, which spanned 1581.7 cM, with a mean distance between SNPs of 0.34 cM. The 4,608 SNPs were located in 2,849 unique locations on the linkage map, with an average inter-location space at 0.56 cM. There were 2,516 SNPs on the female map, and the number of unique locus was 1,902. However, the male map contained more numbers of SNP (2,939) and unique locations (2,005). The total length of the female and male maps was 1,370.9 and 1,335.5 cM, respectively.Conclusions: The high-resolution genetic linkage maps will be very useful for QTL analyses and marker-assisted selection (MAS) for economically important traits in molecular breeding of the orange-spotted grouper. © 2013 You et al.; licensee BioMed Central Ltd. Source


Cui M.,Jinan University | Zhang Q.,Jinan University | Yao Z.,Jinan University | Zhang Z.,Jinan University | And 2 more authors.
Fish and Shellfish Immunology | Year: 2010

The present study aimed to examine the expression of immunoglobulin M (IgM) gene in orange-spotted grouper (Epinephelus coioides) following thermal stress, bacterial infection, and immunization with formalin-killed Vibrio alginolyticus, a kind of bacterial pathogen that causes septicemia. In heat shock experiments, twenty-five healthy orange-spotted grouper were kept in tanks with seawater at 37±0.5°C for one hour heat-shock treatment, and then returned to 27±0.5°C seawater tanks. In bacterial challenge experiments, two hundred healthy orange-spotted grouper were infected or immunized intraperitoneally with 0.1mL V. alginolyticus resuspended in PBS at 5×104cellsmL-1. Blood and organ samples (head kidney, spleen, and thymus gland) were collected and frozen immediately in liquid nitrogen for subsequent real-time PCR analyses at various times. IgM mRNA expression decreased significantly in gill, head kidney, spleen, intestine, and thymus gland from the 3rd hour after heat stress (37°C), and consistently declined until the 48th hour, but increased in blood cells from the 3rd hour to 48th hour. There was a significant increase of IgM gene transcripts in head kidney, spleen, thymus gland and blood cells of the infected and immunized grouper. There was a clear time-dependent expression pattern of IgM mRNA expression after V. alginolyticus infection and vaccination, with a significant increase at 2 weeks post-challenge and a peak at 4 weeks or 5 weeks for the infection or vaccination group, respectively. The level of IgM mRNA expression in the infected grouper was not only higher, but also earlier than that of the immunized group. These data demonstrated that IgM mRNA expression of the grouper was influenced by acute thermal stress and V. alginolyticus challenge. © 2010 Elsevier Ltd. Source

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