Dataset Information

D-Tryptophan enhances the reproductive organ-specific expression of the amino acid transporter homolog Dr-SLC38A9 involved in the sexual induction of planarian Dugesia ryukyuensis.

ABSTRACT:

Background

Many animals switch between asexual and sexual reproduction in nature. We previously established a system for the sexual induction of planarian Dugesia ryukyuensis by feeding asexual planarians with minced sexual planarians. We identified DL-tryptophan (Trp) as one of the sex-inducing substances. DL-Trp can induce ovarian development, the first and essential step of sexual induction. D-Trp must act as a principal bioactive compound in terms of ovarian development, because the ovary-inducing activity of D-Trp was 500 times more potent than that of L-Trp. However, how Trp controls sexual induction is still unknown.

Results

In this study, qRT-PCR analyses suggested that the putative amino acid transporter gene Dr-SLC38A9 is highly expressed in sexual worms, especially in the yolk glands. In situ hybridization analyses showed that Dr-SLC38A9 is expressed in the ovarian primordia of asexual worms and in the mature ovaries, testes, and yolk glands of sexual worms. In addition, Dr-SLC38A9 RNA interference during sexual induction resulted in the suppression of the development of reproductive organs. These results suggest that Dr-SLC38A9 is involved in the development of these organs. Moreover, we demonstrated that the reproductive organ-specific expression of Dr-SLC38A9 is enhanced by the addition of D-Trp.

Conclusion

We propose that D-Trp activates the expression of Dr-SLC38A9 to promote sexual induction in the planarian D. ryukyuensis.

SUBMITTER: Maezawa T

PROVIDER: S-EPMC7981857 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature

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Publications

D-Tryptophan enhances the reproductive organ-specific expression of the amino acid transporter homolog Dr-SLC38A9 involved in the sexual induction of planarian Dugesia ryukyuensis.

Maezawa Takanobu T Ishikawa Masaki M Sekii Kiyono K Nagamatsu Go G Furukawa Ryohei R Kobayashi Kazuya K

Zoological letters 20210320 1

<h4>Background</h4>Many animals switch between asexual and sexual reproduction in nature. We previously established a system for the sexual induction of planarian Dugesia ryukyuensis by feeding asexual planarians with minced sexual planarians. We identified DL-tryptophan (Trp) as one of the sex-inducing substances. DL-Trp can induce ovarian development, the first and essential step of sexual induction. D-Trp must act as a principal bioactive compound in terms of ovarian development, because the ...[more]

PMID: 33743841

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Project description:BackgroundDugesia sicula is the only species of its genus not presenting an endemic or restricted distribution within the Mediterranean area. It mostly comprises fissiparous populations (asexual reproduction by body division and regeneration), most likely sexually sterile, and characterized by an extremely low genetic diversity interpreted as the consequence of a recent anthropic expansion. However, its fissiparous reproduction can result in an apparent lack of diversity within the species, since genetic variation within individuals can be as large as between them because most individuals within a population are clones. We have estimated haplotype and nucleotide diversity of cytochrome oxidase I within and among individuals along the species distribution of a broad sample of D. sicula, including asexual and the two only sexual populations known today; and predicted its potential distribution based on climatic variables. Our aim was to determine the centre of colonisation origin, whether the populations are recent, and whether the species is expanding.ResultsThe species presents 3 most frequent haplotypes, differing in a maximum of 11 base pairs. As expected from their fissiparous mode of reproduction, in half of all the analysed localities many individuals have multiple heteroplasmic haplotypes. The distribution of haplotypes is not geographically structured; however, the distribution of haplotypes and heteroplasmic populations shows higher diversity in the central Mediterranean region. The potential distribution predicted by climatic variables based modelling shows a preference for coastal areas and fits well with the observed data.ConclusionsThe distribution and frequency of the most frequent haplotypes and the presence of heteroplasmic individuals allow us to gain an understanding of the recent history of the species, together with previous knowledge on its phylogenetic relationships and age: The species most probably originated in Africa and dispersed through the central Mediterranean. After one or multiple populations became triploid and fissiparous, the species colonized the Mediterranean basin, likely both by its own means and helped by human activities. Its present distribution practically fulfils its potential distribution as modelled with climatic variables. Its prevalence in coastal regions with higher water temperatures predicts a likely future expansion to northern and more interior areas following the increase in temperatures due to climate change.

Project description:BACKGROUND: Planarians are considered to be among the extant animals close to one of the earliest groups of organisms that acquired a central nervous system (CNS) during evolution. Planarians have a bilobed brain with nine lateral branches from which a variety of external signals are projected into different portions of the main lobes. Various interneurons process different signals to regulate behavior and learning/memory. Furthermore, planarians have robust regenerative ability and are attracting attention as a new model organism for the study of regeneration. Here we conducted large-scale EST analysis of the head region of the planarian Dugesia japonica to construct a database of the head-region transcriptome, and then performed comparative analyses among related species. RESULTS: A total of 54,752 high-quality EST reads were obtained from a head library of the planarian Dugesia japonica, and 13,167 unigene sequences were produced by de novo assembly. A new method devised here revealed that proteins related to metabolism and defense mechanisms have high flexibility of amino-acid substitutions within the planarian family. Eight-two CNS-development genes were found in the planarian (cf. C. elegans 3; chicken 129). Comparative analysis revealed that 91% of the planarian CNS-development genes could be mapped onto the schistosome genome, but one-third of these shared genes were not expressed in the schistosome. CONCLUSIONS: We constructed a database that is a useful resource for comparative planarian transcriptome studies. Analysis comparing homologous genes between two planarian species showed that the potential of genes is important for accumulation of amino-acid substitutions. The presence of many CNS-development genes in our database supports the notion that the planarian has a fundamental brain with regard to evolution and development at not only the morphological/functional, but also the genomic, level. In addition, our results indicate that the planarian CNS-development genes already existed before the divergence of planarians and schistosomes from their common ancestor.

Dataset Information

D-Tryptophan enhances the reproductive organ-specific expression of the amino acid transporter homolog Dr-SLC38A9 involved in the sexual induction of planarian Dugesia ryukyuensis.

Background

Results

Conclusion

Publications

D-Tryptophan enhances the reproductive organ-specific expression of the amino acid transporter homolog Dr-SLC38A9 involved in the sexual induction of planarian Dugesia ryukyuensis.

Similar Datasets

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