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1.
The full-length cDNA, encoding the orange-spotted grouper β-actin and spanning 1920 bp including a poly (A) tail, was cloned
from its brain cDNA library. The open reading frame encodes a protein of 375 amino acids. Sequence analysis indicated that
it contained the typical structural features of cytoplasmic actins, and showed higher homology with other vertebrate β-actin
than any other members of the actin family. The partial genomic sequence indicated that the organization of the β-actin gene
in the orange-spotted grouper might also be conserved. Northern blot analysis indicated that it was expressed at high levels
in the brain, spleen, adipose tissue, ovary, and liver, but at low levels in the gill filament and heart, and at a very low
level in the kidney. The expression of β-actin gene in the skeletal muscle was barely detectable. These results indicated
that the expression of the orange-spotted grouper β-actin gene showed significant variation in different tissues. Therefore,
caution should be taken when using β-actin gene as an internal control in the normalization of gene expression among tissues.
Whereas, semi-quantitative RT-PCR analysis indicated that treatment with 17α–methyltestosterone (MT) had little effect on
the mRNA expression of β-actin gene in the in vitro incubated hypothalamus, pituitary, and ovary fragments of the orange-spotted grouper, suggesting β-actin can be used as an
internal control for RT-PCR analysis of MT effects on gene expression in these tissues. 相似文献
2.
C. Pelissero J. Nunez-Rodriguez F. Le Menn O. Kah 《Fish physiology and biochemistry》1988,5(3):109-119
An immunohistochemical study of the sturgeon (Acipenser baeri) pituitary was undertaken using antisera directed against hormones from various classes of vertebrates, including the only pituitary hormone available from sturgeon, gonadotrophin. A positive reaction was obtained after application of antisera towards the following hormones 1–24 synthetic ACTH (1-24 ACTH), melanophore stimulating hormone (MSH), ovine prolactin (oPRL), ovine growth hormone (oGH), salmon growth hormone (sGH), carp gonadotrophin (cGTH) and its beta subunit (cGTH), sturgeon gonadotrophin (aciGTH), carp thyrotrophin (cTSH) and subunit of the human thyrotrophin (hTSH). The results demonstrate that, in general, the sturgeon pituitary resembles that of teleosts as regards the distribution of the different cell types: ACTH and PRL cells in the rostral pars distalis, GTH, TSH and GH cells in the proximal pars distalis and MSH and PAS-cells in pars intermedia. In addition to the topographical organization of the sturgeon pituitary, this study provides data on the immunological relationships between sturgeon pituitary hormones and those of other vertebrates. 相似文献
3.
The adenohypophysis (AH) of juvenile pirarucu (Arapaima gigas), a representative species of the Osteoglossomorpha (bonytongue fishes, one of the oldest living groups of the teleosts),
was studied using histochemical and immunocytochemical methods. The AH is comprised of the pars distalis (PD), without a clear
distinction between rostral pars distalis (RPD) and proximal pars distalis (PPD), and the pars intermedia (PI). The neurohypophysis
(NH) is positioned on top of the PD and penetrates and branches into the PI. In the most rostral dorsal portion of the PD,
adrenocorticotropic cells and fusiform gonadotropic cells were found. In the central PD, scarce prolactin-producing cells
and growth-hormone-producing cells were located mainly in the dorsal part, whereas round gonadotropic cells were abundant
in the ventral portion of this region. Human thyrotropin immunoreactive cells were not found in the entire AH. In the PI,
melanotropic, some adrenocorticotropic, and somatolactin-producing cells were located intermingled surrounding the neurohypophyseal
branches. Our results showed that the A. gigas pituitary has some basal characteristics between the ancient Actinopterygii and the more derived teleosts. 相似文献
4.
M.L. Pinillos A.I. Guijarro M.J. Delgado P.C. Hubbard A.V.M. Canário A.P. Scott 《Fish physiology and biochemistry》2002,26(2):197-210
The present study is concerned with pheromone communication in tench (Tinca tinca L.), establishing firstly whether males have a high olfactory sensitivity to some typical teleost sex steroids and prostaglandins;
and secondly whether males and females might be able to synthesise and release some of these steroids into the water. The
C21 steroid, 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P) was found to give large electro-olfactogram responses with an estimated
threshold of detection of 10−12 M. The male tench were equally sensitive to glucuronidated 17,20β-P (10−11.6 M) but 100 times less sensitive to sulphated 17,20β-P (11−9.7 M). Preliminary data from cross-adaptation studies suggest that both the free and conjugated forms are detected by the same
olfactory receptor(s). Male tench also had high olfactory sensitivity to prostaglandin F2α (PGF2α) and 15-keto PGF2α (11−11.5 and 10−11.4 M). They were relatively insensitive, however, to testosterone (T), androstenedione (AD), 11-ketotestosterone (11-KT), 17β-oestradiol
(E2), 17,20β,21-trihydroxy-4-pregnen-3-one (17,20β,21-P) and 17,20α-dihydroxy-4-pregnen-3-one (17,20α-P). Radioimmunoassays were
used to measure the steroids in plasma and water and all samples were processed for the measurement of free, sulphated and
glucuronidated fractions. In females, free 17,20β-P, 17,20α-P, free and glucuronidated T, and AD in plasma showed the largest
increases in response to injection with mammalian gonadotropin-releasing hormone analogue (GnRHa) or Ovaprim (a mixture of
GnRHa and a dopamine inhibitor). Free 17,20β-P was released into the water at the greatest rate. Plasma concentrations of
the two conjugated forms of 17,20β-P were also elevated 18 h after the administration of GnRHa, but not by as much as the
free steroid. In males, AD and 11-KT showed the greatest increase in response to GnRHa and were moreover released into the
water at a higher rate in the treated group than in the control. The data support a possible pheromonal role for free and
glucuronidated 17,20β-P.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
Mitsuo Nyuji Tetsuro Shiraishi Sethu Selvaraj Vu Van In Hajime Kitano Akihiko Yamaguchi Kumiko Okamoto Shizumasa Onoue Akio Shimizu Michiya Matsuyama 《Fisheries Science》2011,77(5):731-739
The physiological functions of pituitary gonadotropins (GtHs) are well established in higher vertebrates, whereas those in
teleosts are still poorly understood. To describe the role of GtHs during gonadal development of female chub mackerel Scomber japonicus, changes in follicle-stimulating hormone (FSH) and luteinizing hormone (LH) cells were investigated immunohistochemically
during the seasonal reproductive and spawning cycles. FSH and LH cells were identified in the different cell types of the
proximal pars distalis (PPD); FSH cells were located in the central PPD, whereas LH cells were localized along the border
of the pars intermedia. To examine changes in FSH and LH cells, the percentage of FSH or LH cell-occupying area in the PPD
was evaluated and represented as FSHβ-immunoreactive (ir) or LHβ-ir levels, respectively. FSHβ-ir levels increased significantly
from immature to the completion of vitellogenesis, whereas LHβ-ir levels were maintained at high levels from early vitellogenesis
to post-spawning. During the spawning cycle, which consisted of four stages from just after spawning to the next oocyte maturation,
both FSHβ-ir and LHβ-ir levels showed no significant changes among different stages; however, LHβ-ir levels remained relatively
high, and FSHβ-ir levels were constantly low. These results suggest that both FSH and LH may be involved in vitellogenesis
and LH may act at final oocyte maturation in female chub mackerel, although the role of FSH during the spawning cycle is still
unclear. 相似文献
6.
7.
In this study we examined the endocrine mediation between environmental factors (temperature and photoperiod) and the brain–pituitary–gonadal
axis in females of pejerrey Odontesthes bonariensis. Changes in the expression of brain gonadotropin-releasing hormones (GnRHs) and gonadotropin (GtH) subunit [follicle stimulating-β
(FSH-β), luteinizing hormone-β (LH-β), glycoprotein hormone-α (GPH-α)] genes, plasma gonadal steroids [estradiol (E2) and testosterone (T)], gonadal histology, and gonadosomatic index (GSI) in adult females exposed to combinations of short-day
(8 h) or long-day (16 h) photoperiods and low (12°C) or high (20°C) temperatures after winter conditions (8 h light, 12°C)
were analyzed. Pejerrey females kept under the short photoperiod had low GSIs, and their ovaries contained only previtellogenic
oocytes regardless of the experimental temperature. In contrast, females exposed to the long photoperiod had high GSIs and
ovaries with vitellogenic oocytes at both temperatures. These fish also showed a significantly higher expression of sGnRH,
pjGnRH, cGnRH-II (the three different GnRH variants found to date in the pejerrey brain), FSH-β, LH-β and GPH-α genes and
plasma E2 levels than those at the shorter photoperiod. No significant changes were observed in plasma T levels. Based on these results,
we concluded that the increase in day length but not that of temperature triggers the maturation of pejerrey females after
the winter period of gonadal rest and that this occurs by an integrated stimulation of the various components of the brain–pituitary–gonad
axis. 相似文献
8.
Follicle-stimulating hormone beta subunit (FSHβ) and luteinizing hormone beta subunit (LHβ) have been cloned and characterized
from the pituitary of grass carp (Ctenopharyngodon idella). The full length of FSHβ and LHβ cDNA was 393 bp and 441 bp, with open reading frame encoding proteins of 130 and 146 amino
acids, respectively. Phylogenetic analysis of the proteins of FSHβ and LHβ showed a high homology with other fishes. Homology
analysis also indicated that LHβ has higher conservation than FSHβ. The expression analysis of grass carp FSHβ and LHβ by
RT-PCR suggested that they were only expressed in the pituitary. Real-time quantitative PCR protocols were developed and validated
to measure FSHβ and LHβ mRNAs during ovarian development. The FSHβ and LHβ mRNA level was very low in the pituitaries of early-pubertal
fish and significantly increased during the ovulation period. These results suggested that in grass carp the gonadotropins
synthesized synchronously in order for asynchronous oogenesis to take place. 相似文献
9.
10.
11.
Michiyasu Yoshikuni Naoki Shibata Yoshitaka Nagahama 《Fish physiology and biochemistry》1993,11(1-6):15-24
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.相似文献
12.
Specific binding sites for testosterone have been detected in three compartments of olfactory tissue from brown and rainbow
trout. Binding of3H-testosterone to the membrane fraction of olfactory tissue is of high affinity (Kd = 0.5–1.9 nM) and limited capacity (Nmax = 30–60 fmol mg+1 protein). Binding is reversible, and is eliminated by protease treatment. The membrane binding site exhibits a high degree
of ligand specificity; 11β-hydroxytestosterone, 11-ketotestosterone, 17α-hydroxyprogesterone, 17α,20β-dihydroxy-4-pregnen-3-one,
cortisol, and estradiol-17β all fail to displace testosterone at 20-fold excess while testosterone itself competes successfully.
These attributes are consistent with the presence of specific steroid receptor proteins. Binding of testosterone within the
cytosol is of moderate affinity (Kd = 9.0–23.0 nM) and high capacity (Nmax = 0.5–2.9 pmol mg+1 protein) and is more readily displaced by a number of steroid competitors than is the case for the membrane site. The rate
of association and dissociation of testosterone from the cytosolic binding site is markedly more rapid than the equivalent
processes in the membrane fraction. Binding of testosterone to the nuclear extract is of high affinity (Kd ∼3.0 nM) and limited capacity (Nmax ∼50 fmol mg+1 protein).
There are no substantial differences between species or between sexes in the affinity or capacity of testosterone-binding
sites in nuclear extract or membrane fraction. However, cytosolic testosterone-binding sites are three- to four-fold more
abundant in rainbow trout than in brown trout, and female rainbow trout have more cytosolic binding sites than male rainbow
trout, but a lower affinity for testosterone than male sites.
Preliminary evidence supports the involvement of the membrane-associated testosterone-binding site in olfactory processes.
Rainbow trout display an EOG response to testosterone at a concentration (≥ 10+9 M) which is consistent with the equilibrium dissociation constant (Kd) of the membrane-associated testosterone-binding site. Binding of3H-testosterone to the membrane-associated site shows a pH dependency which is comparable to the effects of pH on the EOG response
to testosterone in intact fish. The attributes of the intracellular testosterone-binding sites are common to testosterone
receptors in other fish tissues which are known androgen target tissues. This suggests that the development and/or function
of salmonid olfactory tissue may be susceptible to influence by endogenous testosterone. 相似文献
13.
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
14.
The potential for predation by the sea stars Asterias rubens and Marthasterias glacialis on seed-size (41 ± 3 mm shell height) juvenile scallops (Pecten maximus), ready for seeding in sea ranching areas, was investigated in a 30-day laboratory predation experiment. There was no significant
difference (P > 0.05) in predation rate of large A. rubens (95–115 mm radium) and large M. glacialis (120–164 mm radius), which averaged 0.88 and 0.71 scallops individual−1 day−1, respectively. Maximum rates of predation were 2.44 scallops individual−1 day−1 for large A. rubens and 3.00 scallops individual−1 day−1 for large M. glacialis. Small M. glacialis (76–87 mm radius) had a significantly lower predation rate than large individuals of either species (average 0.13 scallops
individual−1 day−1, P < 0.05). Small A. rubens (50–80 mm radius) only began to prey on scallops when average scallop size was reduced to 35 mm. Based on estimated density
of sea stars at a Norwegian sea ranching site and average predation rates, a population of scallops seeded at 10 m−2 would be reduced by between 0.5 and 11% in 1 month. Furthermore, using the highest observed predation rate, the degree of
loss of scallops indicated that scallop culture via sea ranching would not be economically viable and thus methods for reducing
scallop predation by sea stars are necessary. 相似文献
15.
16.
B. Piros J. Glogowski R. Kolman A. Rzemieniecki J. Domagala Á. Horváth B. Urbanyi A. Ciereszko 《Fish physiology and biochemistry》2002,26(3):289-295
This paper provides data concerning biochemical composition of milt of two sturgeon species, Siberian sturgeon bred in aquaculture
facility of Inland Fisheries Institute in North Poland and sterlet (from two different populations from Danube and Odra).
Milt plasma of Siberian sturgeon and sterlet, when compared to teleost fish, is characterized by much lower osmolality (up
70 to 96 mOsm kg−1) and protein concentration (0.24–0.58 g l−1). In spite of the presence of an acrosome and acrosin the antiproteinase activity of seminal plasma was low (12.79–25.40 U l−1). Activities of arylsulfatase and β-N-acetylglucosaminidase were found in spermatozoa. This agrees with the presence of an
acrosome in sturgeons sperm. Similarly to mammals, these enzymes are also present in milt plasma. We determined a range of
enzymatic activities from the minimal (seminal plasma) to the maximal damage (supernatants obtained after freezing-thawing
without cryoprotectant). Activities of arylsulfatase, β-N-acetylglucosaminidase, lactic dehydrogenase and acid phosphatase
were released from spermatozoa after freezing-thawing. For this reason they are good potential candidates as a markers of
cryoinjury to sperm acrosome and midpiece.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
17.
G. J. Vermeulen J. G. D. Lambert M. J. P. Lenczowski H. J. Th. Goos 《Fish physiology and biochemistry》1993,12(1):21-30
With the final aim of identifying the testicular steroids involved in the feedback mechanism of the hypothalamus-pituitary-gonad
axis, steroid secretion by the testis of African catfish, Clarias gariepinus, was studied in vitro, by means of gas chromatography followed by mass spectrometry. Testicular fragments of sexually mature catfish raised in
captivity were incubated in L-15 medium with and without catfish pituitary extract (cfPE). Without adding cfPE, 22 steroids
could be identified, amongst which 11β-hydroxyandrostenedione, 11β-hydroxytestosterone, 11-ketotestosterone and 11-ketoandrostenedione
were dominating. After incubation in the presence of cfPE, the concentrations of the four 11-oxygenated steroids were increased
about 4-fold. The amounts of pregnane derivatives in the incubation medium showed the largest increases in the presence of
cfPE. 5β-Pregnane-triol levels, for example, were 60-fold higher than in the medium from control incubations. The secretion
of 5α- and 5β-androstanes was also stimulated by cfPE.
The stimulation was not equal for all steroids, indicating that cfPE not only stimulates total steroidogenesis by increasing
the availability of cholesterol, but also by influencing specific steroid converting enzyme activities.
Part of this work was presented at the IVth International Symposium on the Reproductive Physiology of Fish, 7–12 July 1991, Norwich, U.K. 相似文献
18.
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
19.
Kyoko Suzuki Tomoyasu Yoshitomi Yoichi Kawaguchi Masaki Ichimura Kaneaki Edo Tsuguo Otake 《Fisheries Science》2011,77(3):313-320
Sakhalin taimen Hucho perryi populations have decreased drastically to near extinction. It is urgent to establish an effective conservation strategy based
on an understanding of the characteristics of migration and habitat use of this species. We examined the migration history
of anadromous Sakhalin taimen captured off the Sarufutsu coast, northern Hokkaido, Japan, using otolith Sr:Ca ratios and also
examined the relationship between their otolith Sr:Ca ratios during freshwater and seawater residence in a rearing experiment.
Otolith Sr:Ca ratios of some fish from the Sarufutsu coast showed freshwater levels (0.5–4.0 × 10−3) near the core, which thereafter increased to brackish water levels (4.0–6.0 × 10−3), and then to seawater levels (6.0–10.0 × 10−3) in the outermost regions. Those findings indicate that specimens from the Sarufutsu coast migrated to the brackish water
region or the sea and spent most of their lives there. The anadromous migration pattern including the timing of downstream
migration seems to be flexible among individuals in the species. They migrate between freshwater and seawater or brackish
water several times during their lives, showing extensive habitat use. It is essential to secure the continuity among the
freshwater, brackish water, and seawater areas for their effective conservation. 相似文献
20.
An 8-week feeding trial was conducted in a flow-through system (1–1.5 L min−1) at 27°C to determine dietary protein requirement for Channa punctatus fingerlings (4.58 ± 0.29 g) by feeding six isocaloric diets (18.39 kJ g−1, gross energy). Diets containing graded levels of protein (300, 350, 400, 450, 500 and 550 g kg−1) were fed to triplicate groups of fish to apparent satiation at 09:00 and 16:00 h. Maximum absolute weight gain (AWG; 8.11 g
fish−1), specific growth rate (SGR; 1.82%) and best feed conversion ratio (FCR; 1.48) were recorded in fish fed diet containing
450 g kg−1 protein, whereas protein efficiency ratio (PER; 1.52), protein retention efficiency (PRE; 25%), energy retention efficiency
(ERE; 78%) and RNA/DNA ratio (3.01) were maximum for the group fed dietary protein at 400 g kg−1. Second-degree polynomial regression analysis of AWG, SGR and FCR data against varying levels of dietary protein yielded
optimum dietary protein requirement of fingerling between 462.24 and 476.72 g kg−1, whereas the regression analysis of PER, PRE, ERE and RNA/DNA ratio data showed a lower protein requirement of 438.28–444.43 g kg−1 of the diet. Considering the PER, PRE, ERE and RNA/DNA ratio as more reliable indicators, this protein requirement is recommended
for developing quality protein commercial feeds for C. punctatus fingerlings. 相似文献