碩士 / 國立臺南大學 / 生物科技學系碩士班 / 106 / This thesis comprises two parts to study two proteins responsible for redox reactions:
The first part describes the biotransformation of a commercially available rude extract of soy isoflavones by recombinant Escherichia coli expressing a tyrosinase from Bacillus megaterium. The original crude soy extracts contains significant amounts of the isoflavone glycosides daidzin and genistin. After biotransformation, two major products were isolated and identified as 3'-hydroxydaidzin and 3'-hydroxygenistin, respectively. The free radical scavenging activities of the two 3'-hydroxyisoflavone glycosides were, respectively, higher than the activity of their precursors. This is the first demonstration of the bio-production and potential antioxidant applications of both 3'-hydroxydaidzin and 3'-hydroxygenistin.
In the second part, the unicellular organism Chlamydomonas reinhardtii was used to analyze the function of nucleoredoxin (NRX) genes. There are three members in the NRX family in Chlamydomonas, but their physiological roles and functional differentiation remains unclear. An exogenous DNA insertion was mapped to the 3’UTR of the NRX2 gene in a flagellum-defected mutant HKCW19, but RT-qPCR showed that the NRX2 transcript was not affected. In another nrx2-1 mutant, the NRX2 expression was abolished, but it contained normal flagella and can swim. Therefore, the disruption of NRX2 does not affect flagellar growth. The nrx2-1 mutant contained a higher ratio of large cells and was more sensitive to H2O2 treatment. The absence of NRX2 does not affect the transcript and protein levels of catalase (CAT), an enzyme responsible for H2O2 clearance. However, the activity of CAT is severely reduced in nrx2-1. Interestingly, loss of NRX2 caused the increase of NRX3 mRNA expression while NRX1 was not affected. Both NRX2 and NRX3 mRNA were induced after pH-shock treatment while NRX1 was not. These expression analyses suggest that NRX2 and NRX3 share similar functions or are involved in the same pathway.
| Identifer | oai:union.ndltd.org:TW/106NTNT0111002 |
| Date | January 2018 |
| Creators | WANG, DONG-SHENG, 王東生 |
| Contributors | CHANG, TE-SHENG, TSAO, CHE-CHIA, 張德生, 曹哲嘉 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 127 |
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