博士 / 國立臺灣海洋大學 / 水產養殖學系 / 93 / Abstract
Shrimp disease caused serious economic losses in world shrimp culture industry. These may be relevant in the control of infectious disease in imtensive farming of economically important shrimp. However, it is important to understand the immune mechanism of shrimp for prevent disease. In this project, white shrimp Litopenaeus vannamei was selected as a model species. The study is to focus on the cell adhesion protein, peroxinectin, which regulates and amplifies the immune response of shrimp. The paper is to deals with the purification of peroxinectin and analysis of its immune function, cloning of peroxinectin cDNA and its expression sites, expression of peroxinection under different molt stages, foreign intruders and under different environmental stressors including water temperature, salinity, ammonia-N and nitrite-N.
Peroxinectin-like is a glycoprotein with molecular mass of 83 kDa. The cell adhesive protein was a multifunctional protein with several biological activities including cell adhesion, opsonin, peroxidase and encapsulation. Peroxinectin-like lost its activity under pH 4-2 and heated in 80 oC for 10 min. The cell adhesive activity was calcium-dependent, and it activity increased by sodium alginate and β-1, 3-glucan. The cell adhesive activity of peroxinectin was not associated with proPO system.
The full-length cDNA of peroxinectin was 2,415 bp. The open reading frame encodes 805 amino acids, which contained a 20 amino acid signal peptide. The predicted molecular mass of mature protein was 89.1 kDa with a pI of 7.5. Sequence comparison showed that peroxinection deduced amino acid of L. vannamei had an overall similarity of 92 % and 60 % to that of P. monodon and P. leniusculus, respectively. The 432 bp fragment (partial cDNA) and 1016 bp fragment (genomic DNA) were obtained using specific primers PE2F and PE2R. There were three introns in the 1016 bp (genomic DNA) fragment. RT-PCR and in situ hybridisation indicated that peroxinectin mRNA synthesized in granular cell and semi-granular cell. The sequence of peroxinectin contained a peroxidase domain (~500 amion acid) and amino acids residues necessary for catalytic activity of peroxidase were conserved in white shrimp peroxinectin. Two putative integrin binding motifs, RGD (Arg-Gly-Asp) and KGD (Lys-Gly-Asp) were observed in white shrimp peroxinectin The assay of cell adhesive activity indicated that integrin-binding site was KGD motif, but not RGD motif. Peroxinectin transcript up-regulated significantly after 6 h post Vibrio alginolyticus-injection. The cell adhesive activity and peroxinectin transcript increased significantly for the shrimp exposed to 5 and 10 mg l-1 ammonia-N and nitrite-N. The cell adhesive activity and peroxinectin transcript were decreased significantly for the shrimp under high temperature (34oC) and low salinity (10 ‰). There was no significant difference in peroxinectin transcript under different molt stages, fed with/without 1 g kg-1 sodium alginate, and injected with saline solution, carbon, zymosan and dead V. alginolyticus.
| Identifer | oai:union.ndltd.org:TW/093NTOU5086003 |
| Date | January 2005 |
| Creators | Chun-Hung Liu, 劉俊宏 |
| Contributors | Jiann-Chu Chen, 陳建初 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 145 |
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