title: De Novo Assembly of the Whole Transcriptome of the Wild Embryo, Preleptocephalus, Leptocephalus, and Glass Eel of Anguilla japonica and Deciphering the Digestive and Absorptive Capacities during Early Development.
abstract: Natural stocks of Japanese eel (Anguilla japonica) have decreased drastically because of overfishing, habitat destruction, and changes in the ocean environment over the past few decades. However, to date, artificial mass production of glass eels is far from reality because of the lack of appropriate feed for the eel larvae. In this study, wild glass eel, leptocephali, preleptocephali, and embryos were collected to conduct RNA-seq. Approximately 279 million reads were generated and assembled into 224,043 transcripts. The transcript levels of genes coding for digestive enzymes and nutrient transporters were investigated to estimate the capacities for nutrient digestion and absorption during early development. The results showed that the transcript levels of protein digestion enzymes were higher than those of carbohydrate and lipid digestion enzymes in the preleptocephali and leptocephali, and the transcript levels of amino acid transporters were also higher than those of glucose and fructose transporters and the cholesterol transporter. In addition, the transcript levels of glucose and fructose transporters were significantly raising in the leptocephali. Moreover, the transcript levels of protein, carbohydrate, and lipid digestion enzymes were balanced in the glass eel, but the transcript levels of amino acid transporters were higher than those of glucose and cholesterol transporters. These findings implied that preleptocephali and leptocephali prefer high-protein food, and the nutritional requirements of monosaccharides and lipids for the eel larvae vary with growth. An online database (http://molas.iis.sinica.edu.tw/jpeel/) that will provide the sequences and the annotated results of assembled transcripts was established for the eel research community.
authors.affiliation: Institute of Fisheries Science, College of Life Science, National Taiwan University, Taipei, Taiwan.
authors.forename: Hsiang-Yi
authors.initials: HY
authors.lastname: Hsu
authors.affiliation: Institute of Information Science, Academia Sinica, Taipei, Taiwan.
authors.forename: Shu-Hwa
authors.initials: SH
authors.lastname: Chen
authors.affiliation: Institute of Fisheries Science, College of Life Science, National Taiwan University, Taipei, Taiwan.
authors.forename: Yuh-Ru
authors.initials: YR
authors.lastname: Cha
authors.affiliation: Department of Marine Science and Resources, College of Bioresource Sciences, Nihon University, Fujisawa, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Tsukamoto
authors.affiliation: Institute of Information Science, Academia Sinica, Taipei, Taiwan.
authors.forename: Chung-Yen
authors.initials: CY
authors.lastname: Lin
authors.affiliation: Institute of Fisheries Science, College of Life Science, National Taiwan University, Taipei, Taiwan.
authors.forename: Yu-San
authors.initials: YS
authors.lastname: Han
mesh_terms: D065567:Absorption, Physiological / Q000235:genetics*; D000811:Anguilla / Q000196:embryology* / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D030541:Databases, Genetic; D004063:Digestion / Q000235:genetics*; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D020895:Enterocytes / Q000187:drug effects / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D063990:Gene Ontology; D007814:Larva / Q000235:genetics; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D053858:Metabolic Networks and Pathways / Q000187:drug effects / Q000235:genetics; D058977:Molecular Sequence Annotation; D016366:Open Reading Frames / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017423:Sequence Analysis, RNA / Q000379:methods*; D059467:Transcriptome / Q000235:genetics*
chemical_list: D026901:Membrane Transport Proteins; D012333:RNA, Messenger