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1.
The hemoglobin-β gene of channel catfish, Ictalurus punctatus, was cloned and sequenced. Total RNA from head kidneys was isolated, reverse transcribed and amplified. The sequence of the channel catfish hemoglobin-β gene consists of 600 nucleotides. Analysis of the nucleotide sequence reveals one open reading frame and 5′- as well as 3′-untranslated regions. The open reading frame of the sequence potentially encodes 148 amino acids with a calculated molecular mass of 16.3 kDa. The pI and charge at pH 7.0 of the deduced hemoglobin-β protein were 7.28 and 0.47, respectively. Overall, 22 amino acid residues were conserved throughout the sequences, including His64 and His93, the sites for heme-binding. Unlike the counterpart of other common cultured fish such as Salmo salar, Oncorhynchus nerka, Oncorhynchus mykiss, Cyprinus carpio and Ctenopharyngodon idella, the hemoglobin-β of channel catfish did not have cysteine. The amino acid sequence of channel catfish hemoglobin-β shows 84% homology with that of Silurus asotus (both are in the order Siluriformes). However, comparison with those of other fish species shows homology ranging from 53 to 68%. Structural analysis by the 3D-PSSM program displays that channel catfish hemoglobin-β has eight α-helices, A–H.  相似文献   

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Skin mucus glycoprotein (RGP) was extracted from the skin mucus of rainbow trout, Salmo gairdneri. Alkaline borohydride treatment of RGP yielded a major oligosaccharide alditol NeuAcα2 to6GalNAc-ol and several minor oligosaccharide alditols. A trisaccharide alditol (OS-I) was purified by Sephadex G-25 gel filtration and high-performance liquid chromatography (HPLC). The amount of OS-I was estimated to be 7% in RGP from the amount of GalNAc-ol. Structural determination of the OS-I was examined. Structure of OS-I was identified to be NeuAcα2 to6 (GalNAcα1 to3) GalNAc-ol by α-N-acetylgalactosaminidase digestion, methylation analysis, and 1H-NMR spectroscopy. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

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Yuki  HAMADA  Yuji  NAGASHIMA  Kazuo  SHIOMI 《Fisheries Science》2004,70(6):1137-1143
ABSTRACT:   Parvalbumin, a calcium-binding sarcoplasmic protein of approximately 12 kDa, represents the cross-reactive, major allergen in fish. In consideration of the fact that parvalbumin is contained at high levels not only in fish muscle but also in frog muscle, the present study was undertaken to clarify whether fish-allergic patients react to two parvalbumins (α- and β-parvalbumins) purified from the bullfrog Rana catesbeiana , which is sometimes consumed as a delicacy in Japan. In enzyme-linked immunosorbent assays (ELISA), sera from 12 of the 14 patients tested reacted equally to both parvalbumins purified from the Pacific mackerel Scomber japonicus and the bigeye tuna Thunnus obesus . Of the 12 sera positive to fish parvalbumins, eight sera also reacted to α- and β-parvalbumins of the bullfrog with different spectra: one serum reacted strongly to α-parvalbumin, six sera reacted strongly to β-parvalbumin and one serum reacted equally to both α- and β-parvalbumins. In addition, inhibition ELISA experiments revealed cross-reactivity between fish and bullfrog parvalbumins. Based on these results, it is proposed that fish-allergic patients should avoid the consumption of frog meat unless they are accurately diagnosed as lacking immunoglobulin E against frog.  相似文献   

7.
Chalcalburnus tarichi is an endemic cyprinid species living in the Lake Van basin, in eastern Anatolia, Turkey. The present study was undertaken to determine which hormones induce oocyte maturation in C. tarichi. The levels of 17α,20β,21-trihydroxyprogesterone (20β-S), progesterone (P), 17α-hydroxyprogesterone (17α-HOP), 11-deoxycortisol (11-DOC), and 17α-hydroxy-20β-dihydroprogesterone (17,20β-P) were measured in fish caught from Lake Van and the Karasu River, and injected with human chorionic hormone (hCG) (1,000 and 1,500 IU/kg). Oocytes of fish caught from the lake were also incubated in vitro with different doses (50, 200, and 1,000 ng/ml) of 20β-S, 17α-HOP, 11-DOC, and 17,20β-P. 11-DOC was found to be the most effective hormone among those measured for inducing oocyte maturation in vivo and in vitro. 17,20β-P could not be determined in the plasma of any fish in vivo (P < 0.05). 1,000 IU/kg dose of hCG given by injection caused a statistically significant increase in all plasma hormone levels (P < 0.05). It was found that there was a significant decrease in the P level only at 1,500 IU/kg dose of hCG injected (P < 0.05), while the level of other hormones increased at this dose (P < 0.05). It was also determined that all the hormones were effective in germinal vesicle breakdown (GVBD) in in vitro oocyte culture (P < 0.05). However, 11-DOC was found to be the most effective hormone in GVBD at a dose of 200 ng/ml (70% GVBD). In conclusion, 11-DOC synthesized during final oocyte maturation in C. tarichi was found to be a potent inducer of GVBD, which shows that 11-DOC may be described as an oocyte maturation steroid in this species.  相似文献   

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Ovarian developmental stages and serum steroid hormone levels were examined at six different times of day (0100, 0600, 1000, 1300, 1600, 2000 h) in a marine teleost, the Japanese whiting Sillago japonica, which has an asynchronous-type ovary containing oocytes at various stages of development and spawns every day during a period ranging up to three months. The largest oocytes in the ovaries at the active vitellogenic or post-vitellogenic stages were found between 0100 and 1300 h. Oocyte maturation indicated by germinal vesicle breakdown (GVBD) occurred at 1600 h, and ovulated oocytes were observed in the ovaries collected at 2000 h. These processes were accompanied by a significant daily change in serum steroid hormone levels. The serum level of estradiol-17β showed a peak in fish with mature oocytes sampled at 1600 h. In these fish, the second-largest oocytes in the ovaries were at the initial stage of vigorous vitellogenesis, the secondary yolk stage. Therefore the highest level of serum estradiol-17β was considered to be due to the second-largest oocytes. Testosterone levels remained low and constant throughout the experimental period. The serum levels of 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-diOHprog) peaked at 1600 h at which time all fish had mature oocytes. These results indicate that the Japanese whiting possesses a diurnal rhythm of oocyte development including vitellogenesis, oocyte maturation and ovulation, and further suggest that daily cycles in oocyte growth and maturation which simultaneously take place in an ovary are regulated by diurnal secretions of estradiol-17β and the maturation-inducing steroid, 17α,20β-diOHprog.  相似文献   

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This article briefly reviews the current status of investigations, mainly based on the amago salmon,Oncorhynchus rhodurus, on the mechanisms of synthesis and action of 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-diOHprog). Pituitary gonadotropin is of primary importance in triggering meiotic maturation in teleost oocytes. However, the maturational action of gonadotropin is not direct, but is mediated by the follicular production of maturation-inducing substance (MIS). It is now well established that 17α,20β-diOHprog is the major MIS of salmonids. Production of this steroid occursvia the interaction of two distinct cell layers, the thecal and granulosa cell layers (2-cell type model). The first step of the stimulating effect of gonadotropin in both layers is the receptor-mediated activation of adenylate cyclase and formation of cAMP. Our findings suggest that the major stimulating action of gonadotropin on 17α,20β-diOHprog biosynthesis is due to the stimulation of 17α-hydroxyprogesterone production by the thecal layer and the selective induction of thede novo synthesis of 20β-hydroxysteroid dehydrogenase in the granulosa layer. 17α,20β-diOHprog acts at the surface of the oocyte. The early steps following 17α,20β-diOHprog action involve the formation of the major cytoplasmic mediator of this steroid, maturation-promoting factor (MPF). It was shown that goldfish MPF induces meiotic maturation inXenopus oocytes andvice versa. The chemical characterization of fish MPF is important for our understanding of the precise mode of maturational action of 17α,20β-diOHprog.  相似文献   

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Pieces of skin of male and female rainbow trout (Oncorhynchus mykiss) were incubated with testosterone and 11-ketotestosterone as substrates. In immature fish the conversion rate was low. In non-spawning adult males 11-ketotestosterone was reduced to 5α-11KDHT (up to 5.2%). In the fish in spawning condition the 5α-reduction rate was only about 1 to 2%. In the same specimens incubated with testosterone a high 11β-hydroxylase activity (23.8-25% in the male and 13% in the female skin) was found. Similar sex specific differences were observed for the occurence of 5α-reduced metabolites (about 20% in the male and 13% in the female tissue).
Résumé Des fragments de peau de truites arc en ciel (Oncorhynchus mykiss, males ou femelles, ont été incubés avec de la testostérone ou de la 11-cétotestostérone, utilisées comme substrats. Chez les poissons immatures, les taux de conversion restent faibles. Chez les males adultes ne donnant pas de sperme, la 11-cétotestostérone est réduite en 5α-androstane-17β-ol-3,11-dione (jusqu'à 5.2%). Chezles poissons en conditions de fraie, le taux de 5α-réduction est seulement de l'ordre de 1 à 2%. Pour ce derniers individus, les incubations de peau en présence de testostérone montrent l'existence d'une forte activité 11β-hydroxylase (23.8-25% pour le male, et 13% pour la femelle). Des différences liées au sexe sont observées de la même manière dans la production de métabolites 5α-réduits (environ 20% avec le tissu male et 13% avect le tissu femelle).
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Specific binding of [3H]17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-DP) to plasma membranes prepared from defolliculated oocytes of rainbow trout (Onchorhynchus mykiss) was identified and characterized. Binding was rapid and reached equilibrium in 30 min. 17α,20β-DP strongly inhibited [3H] 17α,20β-DP binding in a competitive manner. Scatchard analysis revealed two different binding sites: a high affinity binding site with a Kd of 18 nM and a Bmax of 0.2 pmoles/mg protein; and a low affinity binding site with a Kd of 0.5 μM and a Bmax of 1 pmoles/mg protein. This binding activity was successfully solubilized with n-heptyl-β-D-thioglucoside. [3H]17α,20β-DP binding to solubilized preparations reached equilibrium in 1h, and was competitively inhibited with 17α,20β-DP and 17α,20β,21-trihydroxy-4-pregnen-3-one. However, Scatchard analysis showed a single binding site with a Kd of 0.3 μM. The reason for the disappearance of the high affinity binding site in solubilized preparations remains unclear. These results demonstrate that a specific binding site for 17α,20β-DP exists in the plasma membrane of rainbow trout oocytes.
Résumé Une liaison spécifique de le [3H]17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-DP), avec des membranes plasmiques d'ovocytes défollicularisés de truite arc-en-ciel (Onchorhynchus mykiss), a été identifiée et caractérisée. Sa cinétique est rapide et atteint son équilibre en 30 minutes. Le 17α,20β-DP inhibe fortement, et de manière compétitive, la liaison de la [3H] 17α,20β-DP. Une étude de Scatchard a mis en évidence deux sites diffŕents de liaison: un site de forte affinité, de Kd 18 nM et de Bmax 0,2 pmoles/mg de protéine; et un site de faible affinité, de Kd 0,5 μM et de Bmax 1 pmoles/mg de protéine. L'activité de liaison a été solubilisée, avec succés, par le n-heptyl-β-D-thioglucoside. Dans la fraction soluble, la liaison de le [3H]17α,20β-DP atteint un équilibre en 1h.; et elle est complétement inhibiée par la 17α,20β-DP et le 17α,20β,21-trihydroxy-4-pregnen-3-one. Cependant, une étude de Scatchard ne permet de déceler qu'un seul site de liaison, de Kd 0,3 μM. La disparition du site de liaison de forte affinité dans la fraction soluble reste inexpliquée. Ces résultats démontrent l'existence d'un site spécifique de liaison du 17α,20β-DP dans les membranes plasmiques des ovocytes de truite arc-en-ciel.
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Ovarian steroidogenesis during final oocyte maturation (FOM) in the spotted seatrout (Cynoscion nebulosus) was investigated by incubating ovarian fragments with tritiated pregnenolone, followed by chromatographic separation of the radioactive products. The major tritiated steroid produced during FOM comigrated with 17α,20β,21-trihydroxy-4-pregnen-3-one (20β-dihydro-11-deoxycortisol, 20β-S) on HPLC and TLC. Only minor amounts of radioactive material coeluted with 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-P), 11-deoxycorticosterone (DOC), estradiol-17β and testosterone standards in the HPLC system. Additional chromatography by TLC confirmed the presence of radioactive estradiol-17β and testosterone but not 17α,20β-P and DOC. All the ovarian steroids producedin vitro during FOM were assayed for their ability to induce germinal vesicle breakdown (GVBD) of spotted seatrout oocytes. Twenty grams of ovarian tissue were incubated with human chorionic gonadotropin and exogenous pregnenolone. The steroidal products were purified by HPLC and TLC. Most of the maturation-inducing activity was confined to steroidal material which comigrated in these systems with 20β-S. This material was active at a concentration of 1 ng steroid/ml medium in the GVBD assay. Smaller amounts of material which coeluted with 11-deoxycortisol, DOC, 17α,20β-P and several minor unidentified fractions induced GVBD at concentrations of 10 ng steroid(s)/ml. The structure-activity relationships of authentic steroids in inducing GVBD of spotted seatrout oocytes was investigated. Hydroxylation at the 17α, 20β or 21 positions increased potency to induce GVBD. Steroids with multiple hydroxyl groups at the 17α and 20β positions (17α, 20β-P) and at the 17α, 20β, and 21 positions (20β-S) had maximum biological activity in the GVBD bioassay. The results suggest that 20β-S is a major maturation-inducing steroid in spotted seatrout.  相似文献   

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采用文献调研、实地调查与专家咨询相结合的方法对天津市海水养殖外来物种进行了调查研究,目前天津市海水养殖外来物种共计25种,其中鱼类18种,甲壳类4种,双壳类3种,分析了外来海水物种的影响,归纳海水养殖外来物种存在问题,并有针对性的进行探讨分析。  相似文献   

15.
Hormonal and pheromonal control of spawning behavior in the goldfish   总被引:6,自引:0,他引:6  
Species that employ sexual reproduction must synchronize gamete maturity with behavior within and between genders. Teleost fishes solve this challenge by using reproductive hormones both as endogenous signals to synchronize sexual behavior with gamete maturation, and as exogenous signals (pheromones) to synchronize spawning interactions between fish. This dual role of hormonal products is best understood in the goldfish, an external fertilizer with a promiscuous mating system. Female gonadal growth and vitellogenesis is stimulated by 17β-estradiol (E2) which also evokes release of a recrudescent pheromone. At the completion of vitellogenesis, ovarian E2 production drops and plasma testosterone increases, sensitizing the female gonadotropin II (luteinizing hormone; LH) system to environmental cues (temperature, spawning substrate, pheromones). These cues eventually trigger a LH surge that alters steroidogenesic pathways to favor the production of progestins including 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P). Plasma 17,20β-P stimulates oocyte maturation but is also released to the water along with sulfated 17,20β-P and androstenedione to serve as a preovulatory pheromone. This pheromone stimulates male behavior, LH release, and sperm production. At the time of ovulation, females become sexually active in response to prostaglandin F2α (PGF2α) synthesized in the oviduct. PGF2α and its metabolites are released as a postovulatory pheromone that induces male spawning behavior which further increases male LH and sperm production. Androgenic hormones are required for male behavior and LH release. Although goldfish are gonochorists, hormone treatments can induce heterotypical functions in adults. Similar findings in other fish demonstrate that a sexually bipotential brain is not restricted to hermaphroditic fishes. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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The role of gonadotropin (GTH) in the reproduction of the Japanese flounder, Paralichthys olivaceus, was studied by assessing the changes in the apparent activity of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in the pituitary gland during gonadal maturation by immunohistochemical analyses. Corresponding changes in plasma levels of testosterone (T), estradiol-17β (E2), and 17α,20β-dihydroxy-4–pregnen-3-one (DHP) were also studied. Reared fish at the early spawning to termination stages were sampled from May to August and wild fish at the previtellogenic to termination stages were caught at 3- to 4-week intervals between April and September offshore from the northern mainland of Japan by gill nets. The gonadosomatic index of the reared fish decreased from the early spawning stage to the termination stage, while that of the wild fish increased significantly from the previtellogenic stage to the early spawning stage and decreased thereafter. In the reared fish, the immunostaining intensities of FSH and LH were high during the spawning period, accompanied by high plasma levels of T, E2, and DHP. In the wild fish, the immunostaining intensities of FSH and LH were low during the previtellogenic stage but increased during the maturing and spawning stages. These results indicate that both FSH and LH are likely associated with oocyte maturation in the Japanese flounder.  相似文献   

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Aquaculture, particularly marine‐based production, is one of the fastest growing industries in Indonesia. Indonesia's competitiveness in the trade of aquaculture products is constrained by a lack of research and development (R&D) of new aquaculture species candidates. Mariculture has the greatest potential due to Indonesia's vast marine resources and archipelagic geography. Although there are over 3,000 species of marine fish in Indonesia, only 14 species have been widely cultured, largely finfish. Production is dominated by shrimp, groupers and milkfish. Traditionally, candidate species for mariculture in Indonesia and elsewhere have often been selected on their market value before their biological suitability for culture has been established leading to partially successful R&D efforts or even failure. The present study developed a framework for selecting marine fish species to support mariculture R&D in Indonesia based on an improved analytic hierarchy process (AHP). The approach combined various quantitative and qualitative data and involved different R&D stakeholder groups in the selection process. Ten species that had not been previously researched for their aquaculture potential were identified. The modified approach addressed the interaction complexity of criteria and different preferences across the stakeholders. The involvement of different stakeholders in the selection process not only ensured acceptance of the selected species for further research, but also tested the validity and consistency of the method used in this study. The methodology has relevance for mariculture globally given that efficient candidate selection can help focus efforts and investment in mariculture R&D.  相似文献   

18.
Abstract. Eleven wild-caught dolphin fish ( Coryphaena hippurus L.) from Florida waters and 16 of the same species from an experimental mariculture facility were examined for evidence of parasitic disease. Thirteen (48–1%) were found to be infected with parasites of the digestive tract. Adults of the digenean trematode Dinurus rornatus were present in the stomach and intestine. Invasive metacercarial stages of the same species were found encysted in the somatic musculature, pericardium and stomach wall. Metacercaria were associated with mild inflammatory cell infiltration of the musculature and gastric submucosa and, in one case, focal degeneration of the muscle fibres. In addition, invasive plerocercoidsof an unidentified cestode species occurred in the stomach and intestine of a moribund juvenile fish; the associated lesions included degeneration and ulceration of the gastric and intestinal mucosa, with haemorrhage and granuloma formation in submucosal tissues. These findings indicate that parasitic infection of the digestive tract can be a significant cause of disease in dolphin fish in Florida waters.  相似文献   

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海水养殖业合理的结构与良好的发展趋势有利于促进福建省经济的长远发展。本文基于福建省1983—2012年的海产品产量与海水养殖产量数据,研究了福建省鱼类、虾蟹类、贝类、藻类等海产品和海水养殖产品的产量结构特征,结果表明福建省海水养殖主要以贝类、藻类为主,海洋捕捞主要以鱼类、虾蟹类为主;分析了福建省海水养殖的养殖比、面积、单产等的发展趋势,得出鱼类、虾蟹类增加趋势较大,增产潜力大;针对福建省海水养殖产量结构特征和发展趋势,进行成因分析并提出对策。研究结果可以为渔业部门指导福建省海水养殖业的发展提供参考。  相似文献   

20.
The relationship between plasma and ovarian levels of gonadal steroids was examined in two New Zealand fish species with multiple spawning cycles of differing length. Snapper (Pagrus auratus) have a daily cycle of oocyte development, ovulation and spawning, whereas demoiselles (Chromis dispilus) spawn over 2–3 days during a repeat spawning cycle of 7–9 days. Ovarian and plasma levels of the gonadal steroids 17β-estradiol (E2), testosterone (T), 17-hydroxyprogesterone (17P) and 17,20β-dihydroxy-4-pregnen-3-one (17,20βP) were measured in reproductively active fish captured from the wild. Ovarian levels of E2, T and 17P changed in relation to spawning cycle and gonad stage in both snapper and demoiselles. E2 and T levels were detectable at all times, but highest during vitellogenesis in both species. Cyclic changes of 17P occurred in both species, and levels appeared to depend on the rate of conversion of 17P to other hormones. No changes in ovarian levels of 17,20βP were detected in relation to stage of the spawning cycle in snapper; however, ovarian levels of 17,20βP were highest in demoiselles before spawning when fish undergoing final oocyte maturation predominated. Plasma levels of E2 and T were strongly correlated with ovarian concentrations (r=0.850 and r=0.819 for E2 and T respectively) in demoiselles but there was poor correlation between ovarian and plasma levels of 17P and 17,20βP (r=0.004 and 0.273 respectively), or between ovarian and plasma levels of E2, T, 17P or 17,20βP of snapper (r=0.135, 0.277, 0.131 and 0.279). The poor correlation between plasma and ovarian levels of some steroid hormones suggests that plasma concentrations of steroids may not adequately reflect the reproductive status of the fish during short-term cyclic ovarian changes. It is suggested that this disparity is likely to be most marked in species with ovulatory periodicity of short duration.  相似文献   

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