碩士 / 元智大學 / 生物科技與工程研究所 / 99 / High temperature affects microalgae and causes its death. To solve this problem in order to use microalgae in production of biomass energy, an algae model organism,Chlamydomonas reinhardtii, was applied in this study. We use transgenic lines with increased amount of gene expression of ferredoxin (Fdx) to modify the distribution of photosynthetic electron charge. The transgenic algae have an increased level of photosynthesis redox energy storage, so, they can reduce free radicals to increase their survival rate under high temperatures stress. Under optimum temperature, Fdx also can improve the efficiency of photosynthesis.
Three increased PetF (the photosynthetic electron transfer Fdx) transgenic algae lines, showed 1.2 to 1.7 fold more mRNA expression than the non-transformant by Q-PCR analysis. In this study, four transgenic lines overexpressing Fdx5 (a hypoxic induced Fdx isoform) were generated The results showed that 42℃ high temperature is lethal for Chlamydomonas. the survival rate dropped to 48% in wild-type strain when subjected to 42℃ for 30 minutes, but for all transgenic algae under the same heat treatment the survival rate reached nearly 42 ~ 64% after two hours, indicating that the amount of increased Fdx improves the survival under high-temperature. In addition, after subjecting it to 42℃, 40 minutes of heat treatment, the transgenic algae H2O2 content was 46~58% of wild-type strain. Also, observation under confocal microscopy after staining of intracellular H2O2 , it is almost difficult to detect H2O2 issued under the fluorescent dye in the transgenic algae chloroplast in the heat shock condition, whereas wild-type strain contains large fluorescent signals from H2O2 in chloroplasts, suggesting that the amount of increased Fdx level in Chlamydmonas can improve H2O2 reduction of harmful free radicals. Under the normal condition (25℃ 100 μmol s-1m-2 light), starch content of transgenic lines increased 2.7-3 fold when compared to the wild type under the same dry weight, which verifies that the amount of increased Fdx in transgenic lines of algae can increase the ability of carbohydrate assimilation. Unexpectedly, ectopic expression of Fdx5 significantly increased the amount of the expression of PetF by 1.7-2.8 folds, implying that Fdx5 may be able to influence the expression of PetF.
| Identifer | oai:union.ndltd.org:TW/099YZU05111116 |
| Date | January 2011 |
| Creators | Kui-You Pan, 潘奎佑 |
| Contributors | Li-Fen Huang, 黃麗芬 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 75 |
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