Transcriptomic signatures associated with underlying rapid changes in the early phase brain of bi-directional sex change in .

Teleost fish exhibit remarkable sexual plasticity and divergent developmental systems, including sequential hermaphroditism. One of the more fascinating models of sexual plasticity is socially controlled sex change, which is often observed in coral reef fish. The Okinawa rubble goby, is a bi-directional sex-changing fish.

Bidirectional sex change and plasticity of gonadal phases in the goby Lubricogobius exiguus.

Of the ca. 500 known hermaphroditic fish species, bidirectional sex change and simultaneous hermaphroditism are currently known in 69 and 57 species, respectively. Both bidirectional sex change and simultaneous hermaphroditism are predicted to evolve when mating opportunities are limited, such as in cases of low-density distribution and low mobility of individuals.

Basic Methods for the Study of Reproductive Ecology of Fish in Aquaria.

Captive-rearing observations are valuable for revealing aspects of fish behavior and ecology when continuous field investigations are impossible. Here, a series of basic techniques are described to enable observations of the reproductive behavior of a wild-caught gobiid fish, as a model, kept in an aquarium. The method focuses on three steps: collection, transport, and observations of reproductive ecology of a substrate spawner.

Evolution of bidirectional sex change and gonochorism in fishes of the gobiid genera Trimma, Priolepis, and Trimmatom.

Size-advantage and low-density models have been used to explain how mating systems favor hermaphroditism or gonochorism. However, these models do not indicate historical transitions in sexuality. Here, we investigate the evolution of bidirectional sex change and gonochorism by phylogenetic analysis using the mitochondrial gene of the gobiids Trimma (31 species), Priolepis (eight species), and Trimmatom (two species).

Accumulation of organotins in wharf roach (Ligia exotica Roux) and its ability to serve as a biomonitoring species for coastal pollution.

In this study, we measured the accumulation of tributyltin (TBT) in wharf roach (Ligia exotica Roux) and examined the species' ability to be used for TBT biomonitoring in coastal environments. In an exposure test, wharf roach were exposed to TBT via diet for 2d. TBT was accumulated in wharf roach, and its metabolite dibutyltin was detected.

Histological observation of the urogenital papillae in the bi-directional sex-changing gobiid fish, Trimma okinawae.

The gobiid fish Trimma okinawae changes its sex bi-directionally according to its social status. Morphological changes in the urinogenital papillae (UGP) of this fish have been reported during sex change. However, there have been no detailed observations of such changes.

Sex change in the Gobiid fish is mediated through rapid switching of gonadotropin receptors from ovarian to testicular portion or vice versa.

Sex-changing fish Trimma okinawae can change its sex back and forth from male to female and then to male serially, depending on the social status in the harem. T. okinawae is well equipped to respond to its social status by possessing both ovarian and testicular tissues even though only one gonad remains active at one time.

Molecular cloning and expression of Ad4BP/SF-1 in the serial sex changing gobiid fish, Trimma okinawae.

Involvement of Ad4BP/SF-1 was investigated using the serial sex changing goby Trimma okinawae. First, a cDNA encoding Ad4BP/SF-1 was cloned from ovarian follicles. The open reading frame of goby Ad4BP/SF-1 encodes a protein of 489 amino acids.

Aromatase immunoreactivity and the role of enzymes in steroid pathways for inducing sex change in the hermaphrodite gobiid fish Trimma okinawae.

The role of aromatase (Arom) in the process of bi-directional sex change in the gobiid fish Trimma okinawae was investigated by immunohistochemical methods. Irrespective of sexual phase, gonads comprised both ovarian and testicular tissues. In each sexual phase of females, the 2nd (2DF-M) and 4th (4DF-M) days after initiation of sex change to male, males, and the 2nd (2DM-F), 4th (4DM-F) and 6th (6DM-F) days after the initiation of reversion from male to female, ovarian and testicular histological observations were made.

Gonadal structure of the serial-sex changing gobiid fish Trimma okinawae.

In order to obtain basic information about the role played by endogenous sex hormones in bringing about sex changes in the serial-sex changing gobiid fish Trimma okinawae, the gonadal structure of male and female phases were observed histologically. Steroid-producing cells (SPC; Leydig cells in a testis) were observed ultrastructurally in the ovaries and testes of both female-phase and male-phase fish. In addition, gonadal expression of P450 cholesterol side-chain-cleavage (scc) was examined immunohistochemically.

Characterization of two types of cytochrome P450 aromatase in the serial-sex changing gobiid fish, Trimma okinawae.

To investigate the role of estrogen in the serial-sex changing fish Trimma okinawae, we isolated complementary DNAs encoding two distinct cytochrome P450 aromatase isoforms from adult ovary and brain (termed P450aromA and P450aromB, respectively). Sequence and phylogenic analyses showed that the goby P450arom forms belong to two separate CYP19 subfamilies. Transient expression of these cDNAs in HEK293 cells caused conversion of exogenous testosterone to estradiol-17beta.