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1.
Lunar cycles and reproductive activity in reef fishes with particular attention to rabbitfishes 总被引：7，自引：0，他引：7
Akihiro Takemura Md. Saydur Rahman Sigeo Nakamura Young Ju Park & Kazunori Takano 《Fish and Fisheries》2004,5(4):317-328
Cues from the moon influence synchrony in growth, feeding, migration, behaviour and reproduction of many reef fishes. Compared with comprehensive studies on the annual and daily activities of fish, few physiological studies have paid attention to the importance of lunar cues in reproductive activities. We review mutual and interesting relationships between fish reproduction and environmental changes induced by the moon, with particular emphasis on the reproductive activity of the rabbitfishes (Siganidae). Rabbitfish species exhibit, in nature, a definitive reproductive season, which differs among the tropical areas. During the reproductive season, synchronous spawning of rabbitfish is associated with a particular lunar phase. The lunar phase used by the respective species is similar in different regions on the earth. Histological observations revealed that gonads develop synchronously towards a peak around the spawning lunar phase, after which the gonads return to spent condition. Concomitant with gonadal development, sex steroid hormones were produced under the influence of gonadotropin (GtH). Injections of human chronic gonadotropin (hCG) to the fish that are undergoing active spermatogenesis accelerated testicular maturation. These results suggest that hormonal response in maturing the gonads in rabbitfish is under the regulation of GtH, and that pituitary secretion of GtH according to the lunar cycle accounts for the lunar rhythm in gonadal development. We speculate that the cues from the moon can be recognized by the higher parts of the hypothalamus–pituitary–gonadal axis. Possible relationships between exogenous environmental factors and the lunar‐reproductive rhythm are also discussed. 相似文献
2.
J.K. Sundaray K. Ohta A. Yamaguchi K. Suzuki M. Matsuyama 《Fish physiology and biochemistry》2003,28(1-4):193-195
The wrasse, Pseudolabrus sieboldi, is a diandric protogynous labrid fish. Spawning is performed by a terminal phase (TP) male and an initial phase (IP) female between 6:00 and 9:00 h daily during two-month-long spawning season. In the present study, to investigate the roles of steroid hormones in the diurnal spermatogenesis of the P. sieboldi TP male, all steroid hormones produced in the testis were identified and the synthetic pathways of these steroids were determined. Furthermore, the circulating levels of the major steroids produced were analyzed throughout a day at 3-hour intervals during spawning season. In the testis, 11-ketotestosterone (11-KT), estradiol-17β (E2), 17,20β-dihydoxy-4-pregnane-3-one (17,20β-P) and 17,20β,21-trihydroxy-4-pregnen-3-one (20β-S) were synthesized as the major metabolites. In vitro steroid biosynthesis experiments showed similar results to the circulation profiles of the major steroids. This study is the first to clarify the complete steroidogenic pathways in the gonads of a diandric protogynous species throughout its life, when combined with the results of the steroidogenesis in the ovarian follicles. This is also the first report of a clear diurnal rhythm of the steroid production corresponding to the spermatogenic process in the testis of a male teleost. 相似文献
3.
Masaru Nakamura Ramji K. Bhandari Mikihiko Higa 《Fish physiology and biochemistry》2003,28(1-4):113-117
Using genetically controlled all-female and all-male tilapia (Oreochromis niloticus), the role steroid hormones play in the sex differentiation was analyzed histologically, ultrastructurally, immunohistichemically and experimenntally. The results strongly suggest that endogenous estrogen acts as an ovarian inducer, and that the lack of steroid hormone including androgen is important for testicular differentiation. Moreover, the roles of steroid hormones in protogynous sex change of three-spotted wrasse (Halichoeres trimaculatus) and saddleback wrasse (Tharassoma duperrey) were examined. The results strongly support the hypothesis that the endogenous estrogen plays an important role in protogynous sex change. 相似文献
4.
Heavy metal cadmium (Cd) traces are able to promote growth (growth promoter) and induce early maturation in Oreochromis mossambicus fries of both sexes, whereas, in the adults, they degenerate the gonads and their function. The gathered data on length–weight relation, gonado-somatic index, hepato-somatic index, egg numbers and reproductive hormones such as gonadotropins (GtH-I and GtH-II) and gonadial hormones such as progesterone, testosterone and estradiol levels all prove Cd as an endocrine disruptor. 相似文献
5.
Chengcheng Feng Shihong Xu Yifan Liu Yanfeng Wang Wenqi Wang Jingkun Yang Chunyan Zhao Qinghua Liu Jun Li 《Fish physiology and biochemistry》2018,44(1):35-48
In teleost, sex steroid hormones are critical for reproduction. Progestin is known to promote spermiation. To further understand the functions of progestin via its receptors during the annual reproductive cycle in male turbot (Scophthalmus maximus), we observed testicular development, quantified several sex steroid hormones, detected the expression of progestin receptors, and measured various sperm parameters. Results showed that the turbot testicular structure was of the lobular type. During breeding season, a number of spermatocytes (stage III) developed into spermatids (stage IV), then differentiated into sperm during spermiogenesis (stage V), and finally regressed to spermatocytes (stage VI). Concomitant with testicular development, serum progesterone (P4) and 17α,20β-dihydroxy-4-pregnen-3-one (DHP) exhibited higher levels from stage IV to V than other stages. Furthermore, males with higher motility sperm showed higher levels of P4 and DHP compared with fish with lower motility sperm. These results indicated that P4 and DHP might induce spermatogenesis due to seasonal changes. Concurrently, in testes, the nuclear progesterone receptor (pgr) was expressed throughout the reproductive cycle and its level peaked during spermiogenesis while expression of membrane progestin receptor alpha (mPRα) did not change significantly. However, in sperm, mPRα expression was higher than in testes and had a significant positive correlation with curvilinear velocities (VCL), sperm motility, and motility duration. In conclusion, progestin appears to exert a direct pgr-mediated effect on spermiogenesis and improve sperm motility characteristics depending on the abundance of mPRα protein in sperm during spermiation. 相似文献
6.
B. Lal 《Fish physiology and biochemistry》2007,33(4):455-462
Numerous studies are available reporting the effects of pesticides on reproductive activity in Indian fishes. The majority
of these reports deals with histopathological changes in gonads and endocrine glands involved in the regulation of reproduction
following treatment with different pesticides. Pesticides are reported to cause degenerative changes in gonads and arrest
gametogenic processes either by acting directly on the gonads or by interfering with the secretory activity of the hypothalamo-hypophyseal-gonadal/thyroid
axis that regulates various reproductive events. Secretion of hormones such as gonadotropin-releasing hormone (GnRH), gonadotropin,
growth hormone, adrenocorticotropic hormone (ACTH), testosterone, estrogens, 17,20β-dihydroxyprogesterone and thyroid hormones
are in general lowered, leading to cessation of gametogenesis, vitellogenesis, oocyte maturation, ovulation, spermiation,
etc. Adverse effects of pesticides have also been demonstrated on fecundity, fertilization, hatching, and postembryonic development.
The effects are highly variable and depend on the nature, dose, and mode of application of the pesticides. 相似文献
7.
8.
The seasonal gonadal changes in the edible clam, Paphia laterisulca, from the Kalbadevi Estuary at Ratnagiri were studied for the period from May 1972 to April 1973 with the help of fresh gonad smears and histological study. The observations of gonad smears revealed the probable commencement of spawning between September and April from the occurrence of spent gonads. Male and female clams were present in almost equal numbers throughout the year.Histological details revealed that the clam P. laterisulca has a prolonged spawning period extending from mid-September to the end of March with two peaks, the first in October–November and the second in February–March. Lysis of the ripe gametes in both sexes for 2.5 months preceding spawning was observed. The second spawning peak was followed by regression in the gonads.Active gametogenesis was observed in May and June (33.5°C and 30.0°C), and again in December and January (21.5°C and 26.0°C) in clams that had spawned during the first spawning peak.The spawning stimulus in Paphia laterisulca appeared to be the sudden increase in salinity (from 4.1 to 22.5‰) in September in the Kalbadevi Estuary. 相似文献
9.
K. Ohta J.K. Sundaray T. Okida M. Sakai T. Kitano A. Yamaguchi T. Takeda M. Matsuyama 《Fish physiology and biochemistry》2003,28(1-4):173-174
The protogynous wrasse, Pseudolabrus sieboldi, is a good model for studying the physiological mechanism of sex change in teleosts. We established a way to induce sex change bidirectionally by controlling the social conditions in captivity. This is the first report of a reversed sex change in a promiscuous species. After identifying all the steroid hormones produced in the ovarian follicles and testis, and clarifying their synthetic pathways, we examined the function of the sex steroids in the sex change of P. sieboldi. We concluded that the activation of 17β-HSD-III is the first step in inducing morphological and functional change from an ovary to a testis. 相似文献
10.
During the critical time of sex determination, fish gonads are liable to chemicals and environmental factors that can disrupt the normal course of sex differentiation. This study was conducted to examine the possibility of a combined effect of water temperature and an exogenous steroid hormone (estradiol-17β, E2) on the process of sex differentiation of Japanese medaka (Oryzias latipes) of the d-rR strain. Sex reversal experiments conducted at different temperatures (14, 18, 22, 26, 30, and 34 °C) and E2 concentrations (0, 1 and 10 ppb) showed that the percentage of feminization of genotypic males into phenotypic females decreased with increasing temperature for both E2 concentrations, suggesting a marked synergism between the two factors. 相似文献
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12.
J. G. D. Lambert R. van den Hurk W. G. E. J. Schoonen J. W. Resink P. G. W. J. van Oordt 《Fish physiology and biochemistry》1986,2(1-4):101-107
In general, female zebrafish,Brachydanio rerio, ovulate only in the presence of males. The stimulant must be pheromonal as even male holding water is capable of inducing ovulation. After ovulation the mating phase begins. During this phase the male follows the female and oviposition as well as fertilization takes place. Both the ovulation and the mating are controlled by pheromones synthesized by the gonads. Ovulation can be induced by testicular homogenates. After the lipid material has been extracted from the testicular homogenates, the remaining aqueous phase can still induce ovulation. However, when the aqueous phase is treated with the enzyme-glucuronidase, it loses the ability to induce ovulation. This is an indication that glucuronides, probably steroid glucuronides, are the compounds responsible.During the mating phase, ovulated female zebrafish become attractive to males. It was found that, after ovulation, ovarian extracts contain the compounds responsible for attracting males. The attractant consists of a mixture of steroid glucuronides.After incubation of the gonads with3H-precursors seven steroid glucuronides have been identified in the testis and five in the ovary.Under fish culture conditions the African catfish,Clarias gariepinus, can produce postivitellogenic oocytes throughout the year. However, in capitivity neither males nor females spawn. In female catfish maturation and ovulation can be induced by treatment with gonadotropins. It might be possible that, analogous to the zebrafish, some reproductive processes in the catfish have to be induced by pheromones. It has been demonstrated that pheromonal compounds released by the seminal vesicles are involved in the attraction of female conspecifics. The steroid glucuronide synthesizing capability of the testes and the seminal vesicles of the male catfish are examined, as well as that of the ovary before and after ovulation of the female catfish. Both testes and seminal vesicles appear to be capable of steroid biosynthesis but only the latter synthesizes steroid glucuronides. Six of these conjugates have been isolated and identified. In the female catfish the ovaries are capable of synthesizing seven steroid glucuronides, but only after ovulation. 相似文献
13.
Wen-Hung Twan Hua-Fang Wu Jiang-Shiou Hwang Yan-Horn Lee Ching-Fong Chang 《Fish physiology and biochemistry》2005,31(2-3):111-115
Most broadcast spawning scleractinian corals synchronously release gametes during a brief annual spawning period. In southern
Taiwan, the mass spawning of scleractinians occurs in lunar mid-March. Endocrine system has been proposed to play important
roles in this annual phenomenon. A scleractinian coral, Euphyllia ancora has been selected as a model for the hormones and reproduction studies. We detected the presence of estradiol (E2), testosterone
(T), glucuronided E2, glucuronided T, aromatase, immunoreactive (ir)GnRH in coral polyps E. ancora. Annual profiles of sex steroids, aromatase, and irGnRH have also been characterized. We found the parallel increases in
irGnRH concentrations, aromatase activity and free E2 and glucuronided E2 concentrations at the time of coral mass spawning.
The stimulation of mammalian (m)GnRH agonist in the increased aromatase activity and sex steroid concentrations was also observed
in corals. Coral extracts (irGnRH) and mGnRH agonist had a similar dose-dependent effect on luteinizing hormone release in
black porgy fish pituitary cells (in vitro). In conclusion, our data suggest that irGnRH and glucuronided E2 may play important
roles in the control of reproduction and mass spawning in corals. Corals already evolved the vertebrate-type hormone system
in the sexual reproduction. 相似文献
14.
Various endocrinological and immunological parameters involved with the seasonal changes of immunocompetence in common carp, Cyprinus carpio reared under natural conditions were investigated. Plasma concentrations of steroid hormones, IgM levels, IgM-secreting cell (IgMSC) numbers, and water temperature were considered as major parameters. Testosterone, 11-ketotestosterone in males and estradiol-17β in females detected by RIA, increased simultaneously with gonadal maturation, but no significant correlation was found with IgM production measured by ELISA. IgM levels were very high during the spawning season, but did not fluctuate much during the other seasons even at high water temperatures. These changes of IgM are certainly related to sexual maturation. In addition, IgMSC numbers were also high during the spawning season. This positive interaction between endocrine and immune parameters could contribute to the immune systems of common carp being more effective during spawning season. Interestingly, cortisol levels increased with the water temperature and were high during the spawning season, but had no suppressive effect on the IgM levels and IgMSC numbers. 相似文献
15.
P. Mark Lokman Kataraina A.N. George Graham Young 《Fish physiology and biochemistry》2003,28(1-4):283-285
To investigate the hormonal control of previtellogenic oocyte growth in eel, Anguilla australis, ovarian explants were incubated with or without different doses of steroid (11-ketotestosterone, estradiol-17β) or peptide hormones (ovine growth hormone, human insulin-like growth factor-I, human chorionic gonadotropin, porcine insulin) for 18 days. 11-Ketotestosterone, but not estradiol-17β, significantly increased oocyte diameters at physiological doses (30–100 ng/mL). Similarly, incubation with insulin-like growth factor-I, but not any of the other peptide hormones tested, resulted in increased oocyte diameters at high physiological doses (≥30 ng/mL). These data implicate androgens and hormones from the metabolic axis in mediating growth of previtellogenic oocytes in eel. 相似文献
16.
SOX9基因在脊椎动物性别决定和性腺分化中扮演重要的调控作用。从mRNA和蛋白水平分析中华鳖SOX9基因在不同组织中的差异性表达、在胚胎性腺和成年睾丸中的细胞定位以及在性逆转中的表达变化,研究SOX9基因在中华鳖性别分化中的调控作用。Real-time PCR结果显示,SOX9基因在中华鳖雄性性腺中特异性表达。免疫荧光染色分析显示,SOX9蛋白在雄性18期胚胎性腺中开始表达,随着性腺的发育,SOX9蛋白定位于性腺Sertoli前体细胞细胞核中;而在雌性胚胎性腺并未见其表达。此外,在雌激素诱导的雄性向雌性性逆转胚胎中,SOX9基因显著下调,而在芳香化酶抑制剂诱导的雌性向雄性性逆转胚胎中,SOX9基因表达则显著上升。研究表明,SOX9基因为中华鳖雄性特异性基因,参与雄性性腺的发育过程,可能在中华鳖早期性别分化过程中起调控作用。 相似文献
17.
Julio Berbejillo Anabel Martinez-Bengochea Gabriela Bedó Denise Vizziano-Cantonnet 《Fish physiology and biochemistry》2013,39(1):91-94
The sex differentiation period of the Siberian sturgeon was investigated through expression profiling of two testicular markers (dmrt1 and sox9). At the molecular level, a clear sexual dimorphism of dmrt1 and sox9 was observed in 3-year-old fish with immature gonads, in which males showed higher expression of these genes. Among 16-month-old sturgeons cultured in Uruguay, gonad morphology analyses showed one group of fish with undifferentiated gonads and a second group which had started their histological differentiation into ovaries or testes. dmrt1 showed a significantly higher expression in testes of recently differentiated fish, but this was not the case for sox9. In undifferentiated fish, we observed two clearly different groups in terms of expression: one group of fish over-expressing male markers (dmrt1, sox9) and another group of fish showing very low expression of these genes. This suggests that fish undergoing male differentiation can be identified by their profiles of gene expression before they undergo morphological differentiation. 相似文献
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19.
《Fisheries Research》2008,89(1-3):15-23
Catch-per-unit-of-effort (CPUE) data were collected from anglers participating in gamefish tournaments off the coast of New South Wales, Australia, over nine consecutive years (1994–2003). Mean catch rates for 381 tournament days were aggregated by “lunar phase day” in order to analyse relationships between CPUE and lunar phase for eight primary gamefish species. Circular–linear correlation analysis identified significant relationships between moon phase and CPUE for black marlin (Makaira indica), blue shark (Prionace glauca), shortfin mako shark (Isurus oxyrinchus), dolphin fish (Coryphaena hippurus), and yellowfin tuna (Thunnus albacares) while no significant relationship was evident for blue marlin (Makaira mazara), striped marlin (Tetrapterus audax) and tiger shark (Galeocerdo cuvier). Periodic regression was used to identify the nature of the relationship between lunar phases and catch rates for these species. A consistent pattern of catch rates peaking over the period from the new moon to the first quarter was observed for blue shark, mako shark, dolphin fish and yellowfin tuna. Results for black marlin differed, with catch rates increasing to a peak between the full moon and the last quarter. We suggest that the observed variability in CPUE maybe a result of the movement of prey species in association with lunar phase. Further, we hypothesise that the observed species-specific differences in CPUE of gamefish are primarily mediated by physiological adaptations and limitations, which directly affect the ability of these predators to maintain access to their prey. 相似文献
20.
Yixue Li Zhi He Shuxia Shi Yize Zhang Dong Chen Weimin Zhang Lihong Zhang 《Fish physiology and biochemistry》2016,42(6):1609-1619
Synaptonemal complex protein 3 (Scp3), which is encoded by scp3, is a meiotic marker commonly used to trace the timing of gonadal differentiation in vertebrates. In the present study, the ricefield eel scp3 cDNA was cloned, and a fragment encoding amino acids 49 to 244 was overexpressed. The recombinant Scp3 polypeptide was purified and used to generate a rabbit anti-Scp3 polyclonal antiserum. In adult ricefield eels, scp3 mRNA was predominantly detected in the gonads and faintly detected in discrete brain areas. In the gonads, Scp3 immunoreactivities were shown to be localized to the germ cells, including meiotic primary growth oocytes, spermatocytes, and pre-meiotic spermatogonia. During early ovarian differentiation, immunoreactive Scp3 was not detected in the gonads of ricefield eels at 6 days post-hatching (dph) but was found to be abundantly localized in the cytoplasm of some oogonia at 7 dph, coinciding with the appearance of the ovarian cavity and ovarian differentiation. At 14 dph, strong Scp3 immunostaining was detected on one side of the nucleus with a distinct polarity in some germ cells, presumably at the leptotene stage. Consistent with these results, the expression of scp3 mRNA was faintly detected in the gonads of ricefield eels at 6 dph, increased at 8 dph, and then remained relatively high thereafter. Taken together, these results suggest that the appearance of immunoreactive Scp3 in oogonia could be a marker for early ovarian differentiation in ricefield eels. The translocation of the Scp3 protein from the cytoplasm to the nucleus in the oogonium of ricefield eels appears to be a controlled process that warrants further study. 相似文献