| Abstract: | Neuropeptides play an important role of regulation for the silkworm, Bombyx mori. To fully comprehend the regulation of neuropeptides in the growth of B. mori and to get more neuropeptides in B. mori, the online program tblastn of BLAST and the search program of OpenOffice software were used to screen genes encoding putative neuropeptide precursors in the databases of silkworm genome and theoretical proteins based on the homology and the structure of the neuropeptides conserved in other insects and invertebrates. Several online programs were used to analyze the structures of the genes and the theoretical proteins to predict the mature peptides. As results, 31 neuropeptide gene families with 37 gene subfamilies including allatostatin-A (AST-A), allatostatin-B (AST-B), allatostatin-C (AST-C), allatropin (AT), bombyxin, ecdysis-triggering hormone (ETH), crustacean cardioactive peptide (CCAP), and FMRFamide were identified. A total of 44 neuropeptide genes and 193 mature peptides were predicted. Among them, 73 neuropeptides are amidated at the C-terminal, six neuropeptides are cyclized at the N- terminal, and nine neuropeptides are sulfated. Most of the mature peptides share the similarity because they belong to the same family. But compared with that of other insects, mature peptides of proctolin, CCAP and CAPA-PK are more advanced in the structure. The results suggest that the neuropeptide precursors, which are possessed by almost all the insects, are produced by nerve and endocrine cells of B. mori, and in the course of evolution, differences in the amino acid sequences for most mature peptides formed among different insect species, but the motifs for the same family are highly conserved. This study provided useful information for future research on functions of neuropeptides, which will give us novel insights into the regulation of developmental process, especially at the pupal stage, in the silkworm. |
