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1.
In the present study, the full-length cDNA sequences of leptin (LEP) and its receptor (LEPR) from turbot Scophthalmus maximus were cloned. The cDNA of tLEP was 1126 bp in length encoding 157 amino acids. The amino acid sequence shared low identity with human LEP (18.8 %), but the three-dimensional structures of these two LEPs were strongly conserved. The deduced 1173-amino acid sequence of tLEPR was 28 % identical to human LEPR, and 82 % too range-spotted grouper LEPR, containing all functionally important domains conserved in vertebrate LEPR. Tissue distribution analysis showed that tLEP was abundantly expressed in brain, eyes and liver. The highest level of tLEPR mRNA was found in liver and kidney. After a 9-week feeding trial using diets with different ratios of carbohydrate–lipid (1:6, 1:2, 2:1 and 14:1), it was found that the increase in dietary carbohydrate-to-lipid ratios from 1:6 to 2:1 did not significantly influence tLEP and tLEPR expression in turbot liver (P > 0.05). The hepatic tLEP expression was significantly elevated in treatment with 14:1 dietary carbohydrate-to-lipid ratio (P < 0.05). The hepatic tLEPR mRNA level in group with 14:1 dietary carbohydrate-to-lipid ratio was significantly lower than that in 1:6 group (P < 0.05), but had no significant difference with the other two groups (P > 0.05). These results revealed the important relationship between dietary carbohydrate-to-lipid ratio and LEP expression in turbot.  相似文献   

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为了解金钱鱼促性腺激素受体基因(GtHRs)在金钱鱼性腺发育中的作用,采用反转录PCR(Rt-PCR)与cDNA末端快速克隆(RACE)首次克隆了金钱鱼卵泡刺激素受体(FSHR)和促黄体生成素受体(LHR)的cDNA序列全长。FSHR的cDNA全长2538 bp,编码702个氨基酸,LHR的cDNA全长3315 bp,编码722个氨基酸,它们都含有属于糖蛋白激素受体(GHR)家族的典型跨膜螺旋结构区域(TM helix)。同源性分析显示金钱鱼GtHRs与欧洲鲈的相似性最高,且GtHRs在进化中具有一定的保守性。性腺不同时期表达分析表明,在卵巢Ⅰ期时,FSHR高水平表达,Ⅱ、Ⅲ、Ⅳ期时在较低水平表达。在精巢中,FSHR的表达水平在Ⅰ、Ⅱ、Ⅲ期逐渐升高并在Ⅲ期达到最高,Ⅳ期开始下降。LHR在金钱鱼卵巢和精巢的Ⅰ、Ⅱ、Ⅲ期低水平表达,在Ⅳ期表达水平达到最高。研究表明,FSHR在金钱鱼性腺发育早期扮演重要作用,LHR与卵子和精子的成熟有关。  相似文献   

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AMP-activated protein kinase (AMPK) is a highly conserved and multi-functional protein kinase that plays important roles in both intracellular energy balance and cellular stress response. In the present study, molecular characterization, tissue distribution and gene expression levels of the AMPK α1 and α2 genes from turbot (Scophthalmus maximus) under salinity stress are described. The complete coding regions of the AMPK α1 and α2 genes were isolated from turbot through degenerate primers in combination with RACE using muscle cDNA. The complete coding regions of AMPK α1 (1722 bp) and α2 (1674 bp) encoded 573 and 557 amino acids peptides, respectively. Multiple alignments, structural analysis and phylogenetic tree construction indicated that S. maximus AMPK α1 and α2 shared a high amino acid identity with other species, especially fish. AMPK α1 and α2 genes could be detected in all tested tissues, indicating that they are constitutively expressed. Salinity challenges significantly altered the gene expression levels of AMPK α1 and α2 mRNA in a salinity- and time-dependent manners in S. maximus gill tissues, suggesting that AMPK α1 and α2 played important roles in mediating the salinity stress in S. maximus. The expression levels of AMPK α1 and α2 mRNA were a positive correlation with gill Na+, K+-ATPase activities. These findings will aid our understanding of the molecular mechanism of juvenile turbot in response to environmental salinity changes.  相似文献   

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Transferrin (Tf) plays an important function in iron homeostasis and metabolism of organisms. In this study, we identified and characterized the Tf gene in Megalobrama amblycephala and evaluated its expression in basal conditions as well as after iron overload and experimental infection with Aeromonas hydrophila. Furthermore, we studied the iron binding properties of recombinant Tf. The full-length M. amblycephala Tf complementary DNA (cDNA) (GenBank accession no.: KX698308) of 2245 bp was cloned and contained a 1953 bp open reading frame (ORF) encoding 650 amino acid residues and flanked by a 68 bp 5′ and a 204 bp 3′ untranslated regions (UTR). Predicted conservative structure illustrated that M. amblycephala Tf consisted of two conservative Tf domains. Amino acid sequence alignment revealed that M. amblycephala Tf had high similarity with that of cyprinids deposited in Genbank, and phylogenetic analysis showed that M. amblycephala Tf clustered with Ctenopharyngodon idella and Hypophthalmichthys molitrix. Tissue expression pattern analyses demonstrated that the liver was the main Tf mRNA expressing organ, being significantly higher than other tissues (p < 0.05). In the liver, Tf mRNA expression in fish artificially injected with the pathogenic bacteria A. hydrophila was significantly upregulated, reaching a peak at 12 h post injection (hpi) and then decreasing afterward. The expression in FeCl3-injected fish showed a similar tendency, but reached a peak at 8 hpi. Meanwhile, fish serum iron significantly decreased following A. hydrophila injection, but increased to peak at 4 hpi and then decreased in FeCl3-injected fish. The recombinant M. amblycephala Tf showed iron binding capacity using CAS analysis. These results are helpful to understand the structure and regulation of expression of Tf, as well as the specific function of Tf for both immune responses and iron homeostasis.  相似文献   

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Spexin (SPX), a novel neuropeptide discovered by the bioinformatics approach, has been shown to exert pleiotropic functions in mammals. However, little information regarding the physiological role of SPX is available in teleosts. As a first step, we cloned the spexin gene from a flatfish, the half-smooth tongue sole. The open reading frame (ORF) of tongue sole spexin contained 363 nucleotides encoding a 120 amino acid (aa) preprohormone with a calculated molecular mass and isoelectric point of 14.06 kDa and 5.86, respectively. The tongue sole SPX precursor contained a 27 aa signal peptide and a 14 aa mature peptide flanked by two dibasic protein cleavage sites (RR and GRR). Tissue distribution analysis showed that spexin mRNA could be detected in various tissues, notably in the brain. In addition, fasting stimulated the hypothalamic expression of spexin mRNA. Intraperitoneal injection of SPX increased gnih and gnrh3 mRNA levels in the hypothalamus; however, SPX inhibited the pituitary expression of gh, fshβ, and gthα mRNAs. Overall, our results reveal the existence of a functional SPX in the tongue sole, which could represent an important factor in the neuroendocrine control of flatfish reproduction and growth, and the spexin mRNA expression is regulated by feeding status.  相似文献   

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Multidomain proapoptotic Bcl-2-associated X (Bax) protein is an essential effector responsible for mitochondrial outer membrane permeabilization, resulting in cell death via apoptosis. In this study, two Bax genes of grass carp (Ctenopharyngodon idellus), designated as CiBax1 and CiBax2, were isolated and analyzed. The obtained CiBax1 cDNA is 2058 bp long, with a 579 bp open reading frame (ORF) coding a protein of 192 amino acid residues. The full-length cDNA of CiBax2 is 1161 bp, with a 618 bp ORF coding 205 amino acids. Both CiBax1 and CiBax2 are typical members of Bcl-2 family containing conserved Bcl and C-terminal domains, and they share conserved synteny with zebrafish Bax genes despite the grass carp Bax mapping to different linkage groups. Phylogenetic analysis showed that CiBax1 was clustered with Bax from most teleost fish, and CiBax2 was close to Bax2 from teleost fish but far separated from that of Salmo salar. Quantitative real-time PCR analysis revealed broad expression of CiBax1 and CiBax2 in tissues from healthy grass carp, but the relative expression level differed. The mRNA expression of CiBax1 and CiBax2 was both upregulated significantly and peaked in all examined tissues at days 5 or 6 post-infection with grass carp reovirus. Subcellular localization indicated that CiBax1 protein was localized in both nucleus and cytosol, while CiBax2 protein only in cytosol. Moreover, CiBax2, but not CiBax1 was colocalized with mitochondrion under normal condition. Taken together, the findings would be helpful for further understanding of the function of Bax in teleost fish.  相似文献   

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The luteinizing hormone receptor (LHR) plays a crucial role in female reproduction. In the present study, full-length sequence coding for the LHR was obtained from female turbot (Scophthalmus maximus) by homology cloning and a strategy based on rapid amplification of cDNA end-polymerase chain reaction. The full-length LHR cDNA was 3,184 bp long and contained a 2,058-bp open reading frame which encoded a protein of 685 amino acids. Multiple sequence alignments of the turbot LHR manifested high homologies with the corresponding sequences of available teleosts and representative vertebrates, and significant homology with that of Hippoglossus hippoglossus. In addition, the turbot LHR showed typical characteristics of glycoprotein receptors, including a long N-terminal extracellular domain, seven transmembrane domains, and a short C-terminal intracellular domain. LHR mRNA was abundant in the ovary, but was deficient in extra-ovarian tissues. Furthermore, LHR mRNA gradually developed from previtellogenesis to migratory nucleus stage, with the highest values observed in migratory nucleus stage during reproductive cycle. However, LHR mRNA sharply decreased in atresia stage. These results suggested that LHR is a typical G protein-coupled receptor that is involved in the promotion of turbot ovarian development and may be related to the final maturation and ovulation of oocyte. These findings contribute to the understanding of the potential roles of LHR in controlling the fish reproductive cycle.  相似文献   

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Spermatogenesis is a highly ordered process in the differentiation of male germ cells. Nuclear morphogenesis is one of the most fundamental cellular transformations to take place during spermatogenesis. These striking transformations from spermatogonia to spermatozoa are a result of phase-specific adaption of the cytoskeleton and its association with molecular motor proteins. KIFC1 is a C-terminal kinesin motor protein that plays an essential role in acrosome formation and nuclear reshaping during spermiogenesis in mammals. To explore its functions during the same process in Larimichthys crocea, we cloned and characterized the cDNA of a mammalian KIFC1 homolog (termed lc-KIFC1) from the total RNA of the testis. The 2481 bp complete lc-KIFC1 cDNA contained a 53 bp 5′ untranslated region, a 535 bp 3′ untranslated region, and a 1893 bp open reading frame that encoded a special protein of 630 amino acids. The predicted lc-KIFC1 protein possesses a divergent tail region, stalk region, and conserved carboxyl motor region. Protein alignment demonstrated that lc-KIFC1 had 73.2, 49.8, 49.3, 54.6, 56.5, 53.1, and 52.1% identity with its homologs in Danio rerio, Eriocheir sinensis, Octopus tankahkeei, Gallus gallus, Xenopus laevis, Mus musculus, and Homo sapiens, respectively. Tissue expression analysis revealed that lc-kifc1 mRNA was mainly expressed in the testis. The trend of lc-kifc1 mRNA expression at different growth stages of the testis showed that the expression increased first and then decreased, in the stage IV of testis, its expression quantity achieved the highest level. In situ hybridization and immunofluorescence results showed that KIFC1 was localized around the nucleus in early spermatids. As spermatid development progressed, the signals increased substantially. These signals peaked and were concentrated at one end of the nucleus when the spermatids began to undergo dramatic changes. In the mature sperm, the signal for KIFC1 gradually became weak and was mainly localized in the tail. In summary, evaluation of the expression pattern for lc-KIFC1 at specific stages of spermiogenesis has shed light on the potential functions of this motor protein in major cytological transformations. In addition, this study may provide a model for researching the molecular mechanisms involved in spermatogenesis in other teleost species, which will lead to a better understanding of the teleost fertilization process.  相似文献   

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Prohibitin (PHB) is an evolutionarily conserved mitochondrial membrane protein. It plays a vital role in cell proteolysis, senescence, and apoptosis and is associated with spermatogenesis and sperm quality control in mammals. To study the characteristics of the PHB gene and its potential roles during spermatogenesis in Boleophthalmus pectinirostris, we cloned a 1153-bp full-length cDNA from the testis of B. pectinirostris with an open reading frame of 816 bp, which encodes 272 amino acid residues. Real-time quantitative PCR (qPCR) analysis revealed the presence of phb mRNA in all the tissues examined, with higher expression levels found in the testis, kidney, intestine, and muscle tissues. We examined the localization of phb mRNA during spermatogenesis by in situ hybridization (ISH), showing that phb mRNA was distributed in the periphery of the nucleus in primary and secondary spermatocytes. In spermatid and mature sperm, the phb mRNA gradually moved toward one side, where the flagellum is formed. Immunofluorescence (IF) results showed co-localization of the PHB and mitochondria at different stages during spermatogenesis of B. pectinirostris. The signals obtained for PHB decreased as spermatogenesis proceeded; the strongest detection signal was found in secondary spermatocytes, with lower levels of staining in other stages. Additionally, in the mature germ cells, the PHB signals were weak and aggregate in the midpiece of the flagellum.  相似文献   

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In this study, a selenoprotein W cDNA was cloned from topmouth culter (Erythroculter ilishaeformis), and it was designated as EISelW. The EISelW open reading frame was composed of 261 base pairs (bp), encoding 86-amino-acid protein. The 5′ untranslated region (UTR) consisted of 104 bp, and the 3′-UTR was composed of 365 bp. A selenocysteine insertion sequence (SECIS) element was found in the 3′-UTR of EISelW mRNA. The SECIS element was classified as form II because of a small additional apical loop presented in SECIS element of EISelW mRNA. Bioinformatic approaches showed that the secondary structure of EISelW was a β1-α1-β2-β3-β4-α2 pattern from amino-terminal to carboxy-terminal. Real-time PCR analysis of EISelW mRNAs expression in 17 tissues showed that the EISelW mRNA was predominantly expressed in liver, ovary, pituitary, various regions of the brain, spinal cord and head kidney. Study of intraperitoneal injection showed that the levels of EISelW mRNA in brain, liver, ovary and spleen were regulated by somatostatin 14 (SS14), 17β-estradiol (E2), cysteamine hydrochloride (CSH) and a binary mixture of E2 and CSH, dependent on the dosage. These results suggest that E2, SS14 and CSH status may affect tissues of selenium metabolism by regulating the expression of SelW mRNA, as SelW plays a central role in selenium metabolism.  相似文献   

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Alkaline phosphatases (Alps) belong to a class of phosphate transferases that dephosphorylate lipopolysaccharide (LPS), adenosine triphosphate, and nucleotides. In this study, a 1874-base pair (bp) intestinal alp cDNA sequence was cloned from Lateolabrax maculatus and designated as Lm-alpi. It contained a 1611 bp open reading frame which encoded a protein with 537 amino acids. Protein sequence alignment showed that Lm-AlpI shared 29.8–79.8% identity with its homologs. Lm-AlpI catalytic sites contained three metal ion sites (two Zn2+ and one Mg2+), referring to D73, H184, D348, H349, H352, H464, D389, and H390 residues, which are essential for enzymatic activity and conservation in different organisms. Two predicted disulfide bonds in Lm-AlpI were composed of four cysteines (C152–C214 and C499–C506), which were homologous to those of mammals. Immunohistochemical staining revealed that Lm-AlpI was mainly expressed on the mucosal surface of the gastrointestinal tract, including stomach, intestine, and gastric cecum. Lm-AlpI was mainly located on the plasma membrane of transiently transfected HeLa cells. The mRNA of Lm-alpi was mainly expressed in the intestine, and its expression levels gradually increased after LPS treatment and further increased by 1.81-fold after 48 h. After desalting culture, the relative mRNA expression level of Lm-alpi decreased at 30 and 50 days after hatching (DAH) and then returned to normal levels at 70 DAH. Further experiments demonstrated that the enzyme activity of Lm-AlpI exhibited an expression pattern similar to that of the mRNA expression of Lm-alpi after LPS treatment and desalting culture. This study provided valuable information on the Lm-AlpI functions associated with the mucosal immunity and salinity adaptation of L. maculatus.  相似文献   

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采用同源克隆、生物信息学方法及荧光定量PCR(Real-time PCR)对缩骨鲫(Carassius auratus sogu var.)肌肉生长抑制素(myostatin,MSTN)基因进行克隆,分析和组织表达状况研究。结果显示:缩骨鲫基因组MSTN基因全长4 737 bp,含有两个内含子和三个外显子;编码区长度为1 128 bp,编码375个氨基酸,包括信号肽(1aa~23aa),TGF-β前肽保守区域(34aa~256aa),TGF-β功能区(281aa~375aa),保守的RXXR蛋白酶酶切位点以及C-端活性区域9个保守的半胱氨酸残基,这与其他物种MSTN相似。此外,缩骨鲫与鲫鱼(Carassius auratus)的MSTN氨基酸序列同源性最高,达到96.1%。以β-actin为内参基因,荧光定量PCR分析表明,MSTN在肌肉中表达量最高;脑、眼、心脏中次之;在肝胰脏、卵巢、肠和肾脏中微量表达。  相似文献   

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