Spontaneous olfactory neuroepithelioma in a domestic medaka (Oryzias latipes).

The medaka (Oryzias latipes) Full Life-Cycle Test Guideline

Expression of guanylyl cyclase genes in medaka hybrids (Oryzias curvinotus x Oryzias latipes).

The Hong Kong-originated medaka fish Oryzias curvinotus expresses nine genes (OcGC1 approximately OcGC8 and OcGC-R2) for membrane guanylyl cyclases (membrane GCs) and three genes (OcGCS-alpha(1), OcGCS-alpha(2), and OcGCS-beta(1)) for soluble GC subunits. The deduced amino acid sequences of membrane GCs expressed in O. curvinotus were quite similar to those expressed in the Japanese medaka Oryz...

Occurrence of thymic lymphoma in carcinogenesis bioassay specimens of the Japanese medaka (Oryzias latipes).

Multiple cases of thymic lymphoma were diagnosed in bioassay specimens of Japanese medaka (Oryzias latipes), a small fish species. Lymphoma in chemically exposed specimens was not clearly related to specific compounds, dose, or sex. Multiple cases of lymphoma occurred in three specimens held in one aquarium and in two specimens in two other aquaria, suggesting the possibility of horizontal tran...

Identification of two teleost homologs of the Drosophila sex determination factor, transformer-2 in medaka (Oryzias latipes)

Transformer-2 (Tra2), an RNA-binding protein, is an important regulator in Drosophila sex determination. In vertebrates, however, the role of Tra2 homologues is not known. We identified two teleost homologues of Tra2, which we named Tra2a and Tra2b, in medaka (Oryzias latipes). Furthermore, we demonstrated that both Tra2 mRNAs were predominantly expressed in germ cells of both sexes before the ...

Developmentally regulated and non-sex-specific expression of autosomal dmrt genes in embryos of the Medaka fish (Oryzias latipes)

The dmrtgene family of vertebrates comprises several transcription factors that share a highly conserved DNA-binding domain, the DM domain. Like some of their invertebrate counterparts, e.g. Drosophila doublesex (dsx) and the Caenorhabditis elegans Mab3, several are implicated in sex determination and differentiation. Thus far, dmrt genes represent the only factors involved in sexual developmen...