碩士 / 國立彰化師範大學 / 生物學系 / 93 / Molt-inhibiting hormone (MIH) is considered an important neuro-hormone for the regulation of molting process in crustaceans. Two MIH-like genes, Pev-SGP1 and Pev-SGP2 have been cloned and sequenced from eyestalks of white shrimp, Litopenaeus vannamei. They contain a 315 and 309 bp open-reading frame, and their conceptually translated peptides consist of a 28 amino acid signal peptide, and a 77 and 75 amino acid mature peptide, respectively. Both genes share highest similarity with other known MIH sequences (70~90%). The genes are both composed of three exons and two introns. Besides, the intron insertion site of Pev-SGP1 and Pev-SGP2 are conversed with other known MIH gene: the first intron locates between positions 6 and 7 in the signal peptide, and the second one locates between positions 41 and 42 in the mature peptide. The transcripts of these two genes are only detected in eyestalks, but not in brain, thorathic ganglia, abdominal nerve cord or non-neural tissues. Furthermore, the RNA levels of both genes decrease in the late premolt stage as measured by a real-time quantitative PCR. Concomitantly, the ecdysteriods level in hemolymph measured by radioimmuno assay at defined molt stages shows a significantly increase at late premolt stage. Together, these results suggest that molting process of P. vannamei might be regulated by Pev-SGP1 and Pev-SGP2. Finally, Pev-SGP1 and Pev-SGP2 are sub-cloned into a His-tagged expression vector and the recombinant proteins are expressed in E. coli BL21 (DE3). SDS-PAGE analysis shows that purity of the recombinant proteins fractions is low after affinity column purification and most recombinant proteins are retained inclusion body.
| Identifer | oai:union.ndltd.org:TW/093NCUE5112005 |
| Date | January 2005 |
| Creators | 陳香吟 |
| Contributors | 李奇英 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 114 |
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