Two unrelated putative membrane-bound progestin receptors, progesterone membrane receptor component 1 (PGMRC1) and membrane progestin receptor (mPR) beta, are expressed in the rainbow trout oocyte and exhibit similar ovarian expression patterns

BACKGROUND: In lower vertebrates, steroid-induced oocyte maturation is considered to involve membrane-bound progestin receptors. Two totally distinct classes of putative membrane-bound progestin receptors have been reported in vertebrates. A first class of receptors, now termed progesterone membrane receptor component (PGMRC; subtypes 1 and 2) has been studied since 1996 but never studied in a fish species nor in the oocyte of any animal species. A second class of receptors, termed membrane progestin receptors (mPR; subtypes alpha, beta and gamma), was recently described in vertebrates and implicated in the progestin-initiated induction of oocyte maturation in fish. METHODS: In the present study, we report the characterization of the full coding sequence of rainbow trout PGMRC1 and mPR beta cDNAs, their tissue distribution, their ovarian expression profiles during oogenesis, their hormonal regulation in the full grown ovary and the in situ localization of PGMRC1 mRNA in the ovary. RESULTS: Our results clearly show, for the first time in any animal species, that rainbow trout PGMRC1 mRNA is present in the oocyte and has a strong expression in ovarian tissue. In addition, we show that both mPR beta and PGMRC1, two members of distinct membrane-bound progestin receptor classes, exhibit highly similar ovarian expression profiles during the reproductive cycle with maximum levels during vitellogenesis and a down-expression during late vitellogenesis. In addition, the mRNA abundance of both genes is not increased after in vitro hormonal stimulation of full grown follicles by maturation inducing hormones. CONCLUSION: Together, our findings suggest that PGMRC1 is a new possible participant in the progestin-induced oocyte maturation in fish. However, its participation in the process of oocyte maturation, which remains to be confirmed, would occur at post-transcriptional levels

Directional bias of illusory stream caused by relative motion adaptation

AbstractEnigma is an op-art painting that elicits an illusion of rotational streaming motion. In the present study, we tested whether adaptation to various motion configurations that included relative motion components could be reflected in the directional bias of the illusory stream. First, participants viewed the center of a rotating Enigma stimulus for adaptation. There was no physical motion on the ring area. During the adaptation period, the illusory stream on the ring was mainly seen in the direction opposite to that of the physical rotation. After the physical rotation stopped, the illusory stream on the ring was mainly seen in the same direction as that of the preceding physical rotation. Moreover, adapting to strong relative motion induced a strong bias in the illusory motion direction in the subsequently presented static Enigma stimulus. The results suggest that relative motion detectors corresponding to the ring area may produce the illusory stream of Enigma

Enzyme-linked immunosorbent assay (ELISA) for rainbow trout (Oncorhynchus mykiss) vitellogenin

International audienc

Enzyme-linked immunosorbent assay (ELISA) for rainbow trout (Oncorhynchus mykiss) vitellogenin

International audienc

Psalm 23

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<em>In vitro</em> culture of rainbow trout, <em>Oncorhynchus mykiss</em>, gonads during sex differentiation and gonadogenesis

National audienceThe histological features, steroidogenic activities (aromatase, I I P-hydroxylase) and gene expressions (cyp19A1, cyp11b1, amh, ddx4, gcl, fst) of trout embryonic gonads have been compared before and after 7 days of in vitro culture at 12 degrees C in three different media. MCDB 105 gave the best results and was used to analyse the effect of 50 nM 17 beta-estradiol on testicular cyp11b1 expression. A significant six-fold decrease has been observed for cyp11b1, while amh, ddx4 and gcl did not change

Disrupted sexual cycles in female grass carp (Ctenopharyngodon idella) raised in tropical condition

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<em>In vitro</em> culture of rainbow trout, <em>Oncorhynchus mykiss</em>, gonads during sex differentiation and gonadogenesis

National audienceThe histological features, steroidogenic activities (aromatase, I I P-hydroxylase) and gene expressions (cyp19A1, cyp11b1, amh, ddx4, gcl, fst) of trout embryonic gonads have been compared before and after 7 days of in vitro culture at 12 degrees C in three different media. MCDB 105 gave the best results and was used to analyse the effect of 50 nM 17 beta-estradiol on testicular cyp11b1 expression. A significant six-fold decrease has been observed for cyp11b1, while amh, ddx4 and gcl did not change

Disrupted sexual cycles in female grass carp (Ctenopharyngodon idella) raised in tropical condition

International audienc

Application of a sensitive radioimmunoassay for the measurement of growth hormone in gilthead sea bream (Sparus aurata) and other sparid fish

Ce travail décrit la mise au point d'un dosage radio-immunologique (RIA) de l'hormone de croissance de la Daurade (sbGH). La sensibilité du dosage est de 0,4 ng/mL avec une ED50 de 1,74 ± 0,05 ng/mL. Les coefficients de variation intra- et inter-dosages sont respectivement de 3,4 et 8,8% à la dose de 1,7 ng/mL. Ni les hormones de croissance (GH) de mammifères, ni les gonadotrophines de la Carpe ou du Saumon chinook, ni la prolactine ovine, ni celle du Tilapia ne provoquent de réaction croisée. Les courbes de déplacement obtenues à partir de dilutions sériées de plasma et d'homogénats d'hypophyses de Sparidés (Daurade, Oblade, Sar commun, Pagre, Marbré) sont parallèles à la courbe standard (sbGH). Les homogénats hypophysaires des autres espèces de Perciformes (Serran chevrette, Mulet à grosse tête, Rouget de roche, Brochet de mer) produisent aussi des courbes de déplacement parallèles à la courbe standard. Par contre, les homogénats hypophysaires de la Sole, de la Rascasse rouge, de la Mostelle de roche, du Poisson rouge, de la Truite arc-en-ciel et de l'Anguille européenne, présentent peu ou ne présentent pas de réactivité croisée en fonction du dosage. Ces résultats semblent indiquer que les GH des Perciformes ont de nombreuses similarités de structure. Le dosage RIA de la GH de la Daurade peut donc être utilisé pour quantifier la GH des autres espèces de Sparidés, voire pour quantifier la GH des autres Perciformes si l'on prend soin de le valider pour chaque nouvelle espèce étudiée