Related Experiment Video
Updated: May 3, 2026

Planarian Ovary Dissection for Ultrastructural Analysis and Antibody Staining
Published on: September 10, 2021
Planarian D-amino acid oxidase is involved in ovarian development during sexual induction
Takanobu Maezawa1, Hiroyuki Tanaka2, Haruka Nakagawa3
1Division of General Education and Research, Tsuyama National College of Technology, 624-1 Numa, Tsuyama, Okayama 708-8509, Japan.
Abstract:
To elucidate the molecular mechanisms underlying switching from asexual to sexual reproduction, namely sexual induction, we developed an assay system for sexual induction in the hermaphroditic planarian species Dugesia ryukyuensis. Ovarian development is the initial and essential step in sexual induction, and it is followed by the formation of other reproductive organs, including the testes. Here, we report a function of a planarian D-amino acid oxidase, Dr-DAO, in the control of ovarian development in planarians. Asexual worms showed significantly more widespread expression of Dr-DAO in the parenchymal space than did sexual worms. Inhibition of Dr-DAO by RNAi caused the formation of immature ovaries. In addition, we found that feeding asexual worms 5 specific D-amino acids could induce the formation of immature ovaries that are similar to those observed in Dr-DAO knockdown worms, suggesting that Dr-DAO inhibits the formation of immature ovaries by degrading these D-amino acids. Following sexual induction, Dr-DAO expression was observed in the ovaries. The knockdown of Dr-DAO during sexual induction delayed the maturation of the other reproductive organs, as well as ovary. These findings suggest that Dr-DAO acts to promote ovarian maturation and that complete sexual induction depends on the production of mature ovaries. We propose that Dr-DAO produced in somatic cells prevents the onset of sexual induction in the asexual state, and then after sexual induction, the female germ cells specifically produce Dr-DAO to induce full maturation. Therefore, Dr-DAO produced in somatic and female germline cells may play different roles in sexual induction.
More Related Videos
12:11Analysis of Chromosome Segregation, Histone Acetylation, and Spindle Morphology in Horse Oocytes
Published on: May 11, 2017
08:35Ex vivo Culture of Drosophila Pupal Testis and Single Male Germ-line Cysts: Dissection, Imaging, and Pharmacological Treatment
Published on: September 11, 2014
Related Concept Videos
Oogenesis
Each primary oocyte is surrounded by a layer of pre-granulosa cells, forming what is...
Oogenesis
Ovarian Cycle
Folliculogenesis
Development of the Sexual Organs in the Embryo and Fetus
Near the gonadal ridges, two duct systems are present: the mesonephric ducts (Wolffian ducts) and paramesonephric ducts (Müllerian ducts). These ducts form the basis for the...
Hormonal Control of the Ovarian Cycle
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...