THESIS
2012
xii, 117 p. : ill. (some col.) ; 30 cm
Abstract
Neuropeptides are small peptides that can be released from neurons as signaling molecules which constitute the largest class of intercellular messenger molecules in metazoans. Secreted neuropeptides can have autocrine, paracrine and hormonal effects and play key roles in plenty of physiological processes in both vertebrates and invertebrates. Many sessile marine invertebrates exhibit a complex life history, and the life style transition from planktonic larvae to sessile juveniles (referred as “settlement”) is critical for their population recruitment and development. Reccent researches suggested that larval settlement is under nervous regulation, and neuropeptides/peptide hormones exhibit modulatory functions in this process. Recently, large scale transcriptome sequencing of two marine...[
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Neuropeptides are small peptides that can be released from neurons as signaling molecules which constitute the largest class of intercellular messenger molecules in metazoans. Secreted neuropeptides can have autocrine, paracrine and hormonal effects and play key roles in plenty of physiological processes in both vertebrates and invertebrates. Many sessile marine invertebrates exhibit a complex life history, and the life style transition from planktonic larvae to sessile juveniles (referred as “settlement”) is critical for their population recruitment and development. Reccent researches suggested that larval settlement is under nervous regulation, and neuropeptides/peptide hormones exhibit modulatory functions in this process. Recently, large scale transcriptome sequencing of two marine sessile species, Balanus amphitrite and Hydroides elegans, have been completed, which provided a rich source for peptide discovery. To better characterize neuropeptidome and its potential role in larval settlement and development, in silico transcriptome mining of neuropeptides and peptide hormones in B. amphitrite and H. elegans was conducted, generating around 100 putative mature peptides, most of which were described for the first time in these two species. Comprehensive sequence analysis revealed that in term of neuropeptide evolution, barnacle was placed in an intermediate position between decapod and insect groups, while most of the neuropeptides of H. elegans tended to be “lophotrochozoan specific”. Altogether these discoveries provide an important new source of information with aspect of neuropeptidome evolution of metazoa. Developmental expression profiling of predicted neuropeptide genes were further conducted. Several genes were found to be specifically up-regulated in larval competent stage and down-regulated after settlement, which were subsequently regarded as candidates that might have been involved in regulating larval settlement. In addition, in B. amphitrite, an inhibitor of proprotein convertase related with peptide maturation effectively delayed cyprid metamorphosis. Altogether, new insight into neuropeptides/peptide hormones characterized in this study shall provide a solid foundation for future molecular and physiological investigations of peptidergic control of larval development and settlement process of marine sessile species.
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