碩士 / 國立屏東科技大學 / 水產養殖系 / 92 / Prophenoloxidase activation system which plays an important role in non-self recognition and immune response, is considered as a major defense mechanism in invertebrates especially in insect and crustacean. A close relationship between the proPO activation system expression and the immunity in shrimps has been reported in the past. We have cloned prophenoloxidase gene from the white shrimp (Litopenaeus vannamei) using reverse transcription polymerase chain reaction (RT-PCR) by degenerate primer. Two types of proPO genes (proPO-I, proPO-II) were found in the white shrimp according to sequence similarity search and alignment of nuclecotide sequences. The full-length cDNAs of proPO-I and proPO-II consisted of 2471 and 2504 bp with are 2058 and 2073 bp open reading frame encode 686 and 691 amino acids with predicted molecular mass of 78.1 and 78.8 kDa, respectively. Deduced amino acid sequence identity between the two white shrimp proPOs are 73% whereas the identity against other crustacean proPOs ranged from about 60 to 89%. Furthermore, like other arthropod proPOs, hydrophobic signal peptide sequences were absent in the deduced proPOs from white shrimp. Both types of proPO contain six histidine residues that two copper binding sites, which are evolutionarily the most conserved amino acid residues among all arthropod proPOs. Tissue expression of two types proPO of L. vannamei were only detected in haemocytes. To evaluate exogenous and endogenous factors that affect expressions of two proPO genes by quantitative real-time PCR, the results were showed: In different moult stages of proPO-I gene expression at A stage were significantly higher than B stage, but the proPO-II gene expression is the highest at D0/1 the stage. Two type proPO genes expression after fed content the sodium alginate (1000 mg/kg) for a week, compares has the obvious increase to the control group. In the injection pathogenic bacterium (Vibrio alginolyticus) and the foreign matter aspect, expression of
proPO-I gene expression were significantly higher in V. alginolyticus injection treatments than that in saline injection treatments at 6 and 12 hrs after injections; expression of proPO-II gene expression was significantly lower in V. alginolyticus injection treatments than that in saline injection treatments at 3 hr after injections, but proPO-II gene expression was significantly higher in V. alginolyticus injection treatments than that in saline injection treatments at 12 hr after injections.
| Identifer | oai:union.ndltd.org:TW/092NPUST086006 |
| Date | January 2004 |
| Creators | Ching-Yi Lai, 賴靜怡 |
| Contributors | Winton Cheng, Ching-Ming Kuo, 鄭文騰, 郭欽明 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 129 |
Page generated in 0.0016 seconds