BackgroundThe abalone Haliotis diversicolor is a good model for study of the settlement and metamorphosis, which are widespread marine ecological phenomena. However, information on the global gene backgrounds and gene expression profiles for the early development of abalones is lacking.Methodology/Principal FindingsIn this study, eight non-normalized and multiplex barcode-labeled transcriptomes were sequenced using a 454 GS system to cover the early developmental stages of the abalone H. diversicolor. The assembly generated 35,415 unigenes, of which 7,566 were assigned GO terms. A global gene expression profile containing 636 scaffolds/contigs was constructed and was proven reliable using qPCR evaluation. It indicated that there may be existing dramatic phase transitions. Bioprocesses were proposed, including the ‘lock system’ in mature eggs, the collagen shells of the trochophore larvae and the development of chambered extracellular matrix (ECM) structures within the earliest postlarvae.ConclusionThis study globally details the first 454 sequencing data for larval stages of H. diversicolor. A basic analysis of the larval transcriptomes and cluster of the gene expression profile indicates that each stage possesses a batch of specific genes that are indispensable during embryonic development, especially during the two-cell, trochophore and early postlarval stages. These data will provide a fundamental resource for future physiological works on abalones, revealing the mechanisms of settlement and metamorphosis at the molecular level.

The results revealed that the forsythin from Forsythia suspensa leaves has low or no toxicity via oral administration, and therefore is suitable for further development and applications.

Abalone animals are import models for the study of the early development of marine invertebrates. However, systematical evaluations of internal control genes (ICG) have seldomly been performed. In this study, ten candidate genes were cloned and surveyed for their stability throughout the early developmental period of H. diversicolor using qPCR. In a period from fertilized egg to postlarva, three genes, Y-box protein 1 (YB1), ornithine decarboxylase antizyme 1 (OAZ1) and eukaryotic translation initiation factor 5A (EIF5A), were found to be the most stable and could be used as ICGs. It is suggested that using two genes jointly, such as YB1 and OAZ1, could be sufficiently reliable to normalize the temporal dynamics of other genes. Normalized by YB1/OAZ1, some rough features of early development of a small abalone were characterized. This is the first report of the temporal dynamics of metabolic activities and overall mRNA abundance of abalone animals in early stages. It is also the first time the multi-functional gene YB1 has been described as an internal control for early developmental biology studies. Phylogeny and function of YB1 are further discussed.