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1.
Cytochrome P450c17 (CYP17, 17α‐hydroxylase/17,20‐lyase) is a critical enzyme in the production of androgens and estrogens in vertebrates. A 2102 bp full‐length cDNA of P450c17‐II (CYP17A2) has been isolated from the ovary of half‐smooth tongue sole, Cynoglossus semilaevis which encodes 524 amino acids. The putative P450c17‐II enzyme shares higher sequence identity with those of teleosts than with P450c17‐I of vertebrate. The similarity between the two types of tongue sole P450c17 was 48%.Semi‐quantitative RT‐PCR analysis of spatial expression showed the enzyme was specifically expressed in the ovary and the head kidney. However, temporal expression shows that P450c17‐II can be found in the brain. Furthermore, temporal expression pattern of P450c17‐II in ovary and brain revealed developmental stage‐dependency, and ovary P450c17‐II expressed remarkably throughout the whole reproductive cycle. Otherwise, the expression pattern of P450c17‐II in head kidney indicated negative ovary development‐dependence. In addition, combined with our data on P450c17‐I, T and E2 levels, the results further endorse the critical role of P450c17‐II during shift in steroidogenesis, suggesting that P450c17‐I and ‐II may act together to this physiological process. Based on the present study, we indicate an important role for P450c17‐II during ovarian development. 相似文献
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Shigeho Ijiri Norio Takei Shinji Andachi Kohei Yamauchi 《Fish physiology and biochemistry》2003,28(1-4):209-210
Antibodies against P450scc, P450c17 and P450arom were generated using recombinant proteins. In eel testis, P450scc and P450c17 were immunolocalized as clusters in Leydig cells. In vitellogenic eel ovary, P450scc and P450c17 immunoreactive cells were localized as clusters in the outer layer of the ovarian follicle. In contrast, P450arom seemed to be immunolocalized in the innermost follicle layer. 相似文献
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本研究克隆了仿刺参(Apostichopus japonicus)P450c17基因的全长cDNA,结果表明其cDNA的5′端UTR为256 bp,3′端UTR为250 bp,ORF为1 530 bp。在3′端有特殊序列ATTTA、终止密码子TAA和polyA加尾。其全长cDNA编码509个氨基酸的前体蛋白,预测蛋白分子量57.6 kD,理论等电点5.5。P450c17的氨基酸序列存在长度为25个氨基酸的信号肽,1个长度为22个氨基酸的跨膜区,1个糖基结合位点NHS,1个P450特有的结构域,其氨基酸序列具有明显的细胞色素P450基因家族的特征。结构域中亚铁血红素结合域中的精氨酸R和发挥活性所必须的半胱氨酸C都是保守的。这些结构组成了血红素结合环、质子传递槽和K螺旋及绝对保守EXXR基序。蛋白前体二级结构中无规则卷曲占41.22%,延伸链占12.77%,α–螺旋占46.01%,不含–折叠。氨基酸序列与其他物种氨基酸序列的同源性在35%～41%之间。系统进化树表明仿刺参与长牡蛎(Crassostrea gigas)及文昌鱼(Branchiostoma belcheri)聚为一支,黄颡鱼(Pelteobagrus fulvidraco)、鲇(Clarias gariepinus)、日本鳗鲡(Anguillajaponica)及白斑角鲨(Squalus acanthias)聚为一支,三刺鱼(Gasterosteus aculeatus)、金眼门齿鲷(Stenotomus chrysops)、斑马鱼(Danio rerio)、鲤(Cyprinus carpio)、虹鳟(Oncorhynchus mykiss)、牙鲆及青鳉(Fundulus heteroclitus)聚为一支。研究结果为进一步探讨仿刺参P450c17在性激素调控性别分化方面的功能提供参考。 相似文献
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The effects of water temperature on the development of hermaphroditic gonads in red seabream (Pagrus major) and on mRNA expression of cytochrome P450 aromatase (P450arom) and 11β-hydroxylase were examined. High water temperature suppressed both expression of P450arom and 11β-hydroxylase and the development of oocytes in ovarian portion of hermaphroditic gonads. 相似文献
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在水温分别为20(常温对照组)、25、30℃条件下,采用RT-PCR方法,研究性腺成熟期雄性黄颡鱼组织中P450芳香化酶(P450aromA和P450aromB)的mRNA表达水平,同时测定性腺成熟系数(GSI)、肝重指数(HSI)、肥满度(CF)和血浆睾酮(T),雌二醇(E2)含量。结果表明,P450aromA在性腺发育成熟期雄性黄颡鱼心脏、肝、脾、胃、肾脏、精巢、鳃、脑、头肾、肠管组织中均无表达,P450aromB只在脑和肠中有表达,在脑中表达量高于肠,表达量随着水温升高而显著下降;各组实验鱼血浆T和E2含量与芳香化酶基因表达量存在相关关系。该实验结果表明,P450aromA可能与精子发生相关,可能不参与黄颡鱼精子排放过程;P450aromB在雄鱼脑中高度表达,可能参与性腺成熟期精子活力保持与排放过程,且应激温度越高,对性腺成熟期精子活力保持与排放过程影响越大。 相似文献
8.
饲料中花生四烯酸对发育前期大菱鲆亲鱼性类固醇激素合成的影响 总被引：4，自引：2，他引：2
为研究饲料中不同水平的花生四烯酸(arachidonic acid,ARA)对发育前期的大菱鲆亲鱼性类固醇激素合成量及合成过程的影响,配制3种等氮等脂(脂肪含量13%)的实验饲料,分别含有不同梯度水平的花生四烯酸:0.72%(不添加花生四烯酸精制油的对照组,C),5.63%(添加低水平ARA的处理组,ARA-L)及15.03%(添加高水平ARA的处理组,ARA-H)(各数值均为占总脂肪酸的比例)。每组饲料投喂3个实验桶,每桶放25尾3龄大菱鲆亲鱼(雌雄比例约为1:1)。养殖实验在室内流水系统内进行,每天饱食投喂2次,养殖周期为5个月。养殖结束后,分别取性腺发育前期的雌雄鱼测血清雌二醇和睾酮的含量并检测性腺中性类固醇激素合成相关蛋白质的基因表达量。结果显示:与对照组相比,饲料中高水平的花生四烯酸显著降低了雌鱼血清中雌二醇的含量,而雄鱼血清中睾酮的含量在低水平花生四烯酸处理组显著降低。在卵巢中,饲料中高水平的花生四烯酸显著降低了促卵泡激素受体mRNA的表达量,但是饲料中低水平的花生四烯酸显著提高了17α羟化酶的mRNA表达量。在精巢中,饲料中低水平的花生四烯酸显著降低了固醇合成急性调节蛋白以及17α羟化酶的mRNA表达量,但显著升高了芳香化酶的mRNA表达量。饲料中花生四烯酸提高了性腺、肝脏和肌肉组织中花生四烯酸的含量,但降低了二十碳五烯酸(EPA)的含量,卵巢中的花生四烯酸累积量高于精巢。综上所述,饲料中添加一定量的花生四烯酸抑制了发育前期大菱鲆亲鱼雌二醇和睾酮的合成,在卵巢中,这种抑制作用可能是通过抑制促卵泡激素受体的表达来实现,而在精巢中,可能是通过抑制固醇合成急性调节蛋白以及17α羟化酶来实现。 相似文献
9.
P.H. Strobl-Mazzulla G.C. López L.A. Miranda G.M. Somoza 《Fish physiology and biochemistry》2003,28(1-4):51-52
The molecular cloning of a cDNA encoding the pejerrey brain cytochrome P450 aromatase (P450aromB) is described. This form shares higher identity to other brain aromatases than with their respective ovarian counterparts and the self ovarian aromatase. Tissue-specific expression of both aromatases was examined in pejerrey by RT-PCR. The immunocytochemical distribution of P450aromB was described. 相似文献
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Steroids are known to play a crucial role in gonadal sex differentiation in many non-mammalian vertebrates, but also in the
gonadal sex change of hermaphroditic teleosts. We investigated the expression of two genes encoding key steroidogenic enzymes,
i.e., cytochrome P450 aromatase (P450arom) and cytochrome P45011β-hydroxylase (P45011β), during the sex change of the protogynous
rice field eel, Monopterus albus. Using RT-PCR with degenerate primers, we cloned rice field eel homologous fragments for both genes (rcP450arom and rcP45011β)
as indicated by the high level of homology with P450arom and P45011β sequences from various vertebrates. Gonadal expression
of rcP450arom and rcP45011β mRNA levels were then assessed during the sex change by semi-quantitative RT-PCR and a real-time
RT-PCR. rcP450arom was predominantly expressed in ovary, much less in ovotestis, and barely in testis. Conversely, P45011β
was markedly up-regulated at the onset of testicular development. These findings underline that regulation of steroidogenesis
is an important process in the sex change of protogynous rice field eel, and they clearly indicate that the concomitant down-regulation
of P450arom and up-regulation of P45011β are of pivotal importance to the sex change of this species. 相似文献
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In the present study, we implanted 2‐year‐old female red‐spotted grouper, Epinephelus akaara, with a non‐steroidal aromatase inhibitor (AI), fadrozole, in the breeding season and examined changes in gonadal histology, serum sex steroids, aromatase activities and P450 aromatase (P450arom) gene expression in gonads after AI implantation. Aromatase inhibitor at doses from 0.1 to 10.0 mg kg?1 BW induced a sex inversion and completion of spermatogenesis up to the functional male phase, but doses of 1.0 and 10.0 mg kg?1 BW AI produced more males than 0.1 mg kg?1 BW AI. Serum estradiol‐17β (E2) levels decreased, but 11‐ketotestosterone (11‐KT) levels increased significantly in all the AI‐implanted groups, whereas testosterone (T) levels increased significantly only in the 1.0 mg kg?1 BW AI‐implanted group. Aromatase activities and P450arom gene expression in gonads were inhibited significantly in the AI‐implanted groups, which was in accordance with the decrease in serum E2 levels. These results suggested the optimal dose of AI to induce sex inversion to be 1.0 mg kg?1 BW. Furthermore, the sex inversion induced by AI may be attributed to the inhibition of P450arom gene expression and aromatase activity and the resultant decrease in the biosynthesis of endogenous E2. Meanwhile, the elevated 11‐KT levels were also associated closely with the occurrence of sex inversion in protogynous red‐spotted grouper. 相似文献
13.
异源精子诱导条斑星鲽雌核发育 总被引：1，自引：0，他引：1
用冷冻保存的花鲈精子作为异源精子,采用紫外线（UV）对精子进行照射使其遗传物质失活,然后与卵子进行授精,可以刺激条斑星鲽鱼卵进行雌核发育,在受精后一定时间采用冷休克处理“受精”卵,抑制第二极体排出成功获得了条斑星鲽雌核发育二倍体鱼苗。实验表明,花鲈精子只有经过紫外线照射遗传失活后,才能诱导产生条斑星鲽雌核发育二倍体鱼苗。经过大量实验筛选出诱导条斑星鲽雌核发育的最佳条件为花鲈冷冻精子采用80 MJ/cm2 的紫外线照射,然后与条斑星鲽卵子进行授精,在受精后7~9 min,将受精卵放在-1.0~1.5 ℃海水中进行冷休克处理,持续时间为60~90 min,在此条件下,获得的雌核发育二倍体的相对诱导率达40.68%±7.24%。由于不失活精子与条斑星鲽卵形成的杂交胚只能存活到原肠期,而染色体未被成功加倍的胚胎会由于单倍体的致死效应在孵化前后死亡,所以存活的仔鱼全部为条斑星鲽雌核发育二倍体。采用微卫星标记技术对雌核发育鱼苗进行了分析,证明了雌核发育鱼苗为雌核发育二倍体。首次报道了采用异源冷冻精子诱导条斑星鲽鱼卵进行雌核发育的技术方法,为条斑星鲽性别控制和遗传改良提供了技术手段。 相似文献
14.
黄鳝脑芳香化酶基因cDNA的克隆及组织表达特异性分析 总被引：1，自引：0，他引：1
根据NCBI数据库报道的黄鳝芳香化酶基因的gDNA序列,设计了一对特异性引物.用Trizol试剂盒提取黄鳝脑总RNA,反转录获得cDNA第一条链,进行PCR扩增.扩增产物经过回收、连接、测序后得到了一条长1514 bp的芳香化酶基因cDNA序列.同源性比较表明该基因属于脑型P450aromB,与其他鱼类脑型P450aromB的同源性较高(>70%),与性腺型P450aromA的同源性较低(<60%),与自身性腺型芳香化酶同源性为59.5%.采用RT-PCR的方法对该基因在雄性黄鳝的各组织表达情况进行了分析,结果表明,该基因的转录本较高的表达于脑和精巢中,较低的在皮肤中表达,而在肝脏、心脏、小肠、肌肉等组织中没有检测到该基因的表达. 相似文献
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The effects of aromatizable 17α-methyltestosterone (MT) and non-aromatizable 17α-methyldihydrotestosterone (MDHT) on sex inversion
in red-spotted grouper, Epinephelus akaara, were investigated. Fish were implanted with MT, MDHT and MT+AI (aromatase inhibitor, AI) respectively for one month. The
results showed that the three treated groups turned into transitional stage with intersex gonads, which contained atretic
oocytes and spermatogenic germ cells at all stages of spermatogenesis. The controls did not change sex. The gonads of more
than half MT-implanted fish were in early transitional stages of sex inversion, whereas those of more than half MDHT and MT+AI-implanted
fish were in late transitional stages of sex inversion. No difference in serum estradiol-17β (E2) levels between the controls and the treated groups were observed, whereas 11-ketotestosterone (11-KT) and testosterone (T)
levels increased in all treated groups. Significantly lower gonadosomatic index (GSI) and gonadal aromatase activity were
observed in the treated groups, which were in accordance with the lower mRNA expression of P450aromA. However, P450aromB mRNA
expression increased in the MT group, while it did not change in the MDHT group. These results suggest that the sex inversion
of red-spotted grouper by MT and MDHT implantation might be due to the suppression of P450aromA gene expression, and resulting
in both the decrease of the ovarian estrogen –secretion, as well as the increase in the 11-KT levels. Furthermore, the main
reason for MT being less effective than MDHT might be due to partial aromatization of MT to estrogen. 相似文献
16.
ABSTRACT: To evaluate the aquaculture performance of triploid barfin flounder Verasper moseri , the sex ratio, maturation, growth and the relative proportion of body parts were examined. The sex ratio of triploids was similar to diploids under communal rearing conditions, but the proportion of female diploids was higher than that of triploids under separate rearing conditions. The gonadosomatic index of triploid females was very low even during the spawning season, and the ovaries were rudimentary. These results suggest that triploid barfin flounder females were sterile. In addition, triploid males produced a small quantity of milt containing very few spermatozoa with abnormal shapes. Spermatozoa obtained from triploids were aneuploidies. When normal eggs were fertilized with sperm from triploid males, no fry developed. These results suggest that triploid barfin flounder males were functionally sterile. Triploid males grew more slowly than diploid males, and triploid females showed similar or slower growth than diploid females, whether reared separately (23 months) or communally (35 months). The ratios of visceral weight to the edible parts for triploid males were similar to those for diploid males, but ratios for triploid females were higher than for diploid females during the spawning period. In conclusion, a significant improvement of growth was not found in triploid barfin flounders. 相似文献
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Koichiro Gen Sonoko Yamaguchi Koichi Okuzawa Naoki Kumakura Hideki Tanaka Hirohiko Kagawa 《Fish physiology and biochemistry》2003,28(1-4):77-80
The duality of gonadotropins (GTHs), follicle-stimulating hormone (FSH) and luteinizing hormone (LH), has been confirmed in most teleost species, but very little is known about their biological functions. To elucidate the physiological roles of FSH and LH in fish reproduction, the expression profiles of GTH subunit genes during gonadal development were analyzed in both male and female red seabream. Furthermore, in vitro studies were carried out to examine the effects of GTHs on steroid hormone production and cytochrome P450 aromatase (P450arom) expression in red seabream gonads. In both sexes, LHβ mRNA was maintained at high levels from the early gametogenesis until spawning season, and declined with gonadal regression. Interestingly, FSHβ mRNA levels in males increased in parallel with testicular development, whereas those in female were remained low throughout oocyte development. From in vitro studies using purified red seabream FSH and LH, both GTHs had a similar potency in stimulating 11-ketotestosterone production by testicular slices, while the biological activity of FSH was much lower than that of LH in stimulating production of estradiol-17β by vitellogenic follicles. Moreover, expression of P450arom mRNA was induced by LH, but not FSH, in ovarian follicles in vitro. FSH was also ineffective in inducing maturational competence and final oocyte maturation. These results suggest that, unlike salmonids, FSH may play an important role during gametogenesis in male, but not female, red seabream, whereas LH may be involved in regulation of both early and late gametogenesis in both sexes. 相似文献
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C.C. Sudhakumari B. Senthilkumaran T. Kobayashi D.S. Wang X.T. Chang Y. Nagahama 《Fish physiology and biochemistry》2003,28(1-4):177-178
Present study revealed the expression of ovarian (oP450arom) and brain (bP450arom) type cytochrome P-450 aromatases in the gonads and brains of sex reversed Nile tilapia. 相似文献
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A group of Atlantic salmon (Salmo salar) was followed through their first year of maturation and spawning. At monthly intervals, starting with juvenile fish in December, 5–7 fish of each sex were killed, and liver and plasma were sampled. The last sampling point was of spawning fish in November a year later. Variables in the cytochrome P450 (P450) system were studied in hepatic microsomes, and estradiol 17 was measured in the plasma of females to assess the maturational status. The P450 1A1-mediated 7-ethoxyresorufin O-deethylase (EROD) started at high levels in winter, but decreased to non-detectable activities in pre-spawning females. Decreases, but not to the same extent, were also observed during this period in total cytochrome P450, cytochrome b5, NADPH-cytochrome P450 reductase, and in the content of two immunochemically determined P450 isozymes. At the same time, LSI levels increased in maturing females (starting in July), and GSI levels increased in both sexes (starting in May). Sex specific differences were observed in pre-spawning fish in September and October, with levels of total P450, b5, NADPH-cytochrome P450 reductase, EROD and P450 isozymes significantly lower in females. At the same time, plasma estradiol-17 levels reached peak values in females. The results point to the important role of sex steroids such as estradiol-17 as major factors in the regulation of final sexual maturation. However, this study also indicates that there may be estradiol-17 independent events of equal importance in the early stages of gonadal maturation that may involve the P450 system. The changes observed in the P450 system (as a major drug and steroid metabolizing system) of Atlantic salmon during sexual maturation may be of importance both in the endogenous transduction of hormonal signals, and as a pharmacological basis for designing therapeutic treatment of diseases in the aquaculture industry.Parts of this work were presented at the 5th International Symposium on Responses of Marine Organisms to Pollutants, April 1989 in Plymouth, United Kingdom (Larsen and Goks\/oyr 1989). 相似文献