碩士 / 國立屏東科技大學 / 水產養殖系所 / 106 / The most common forms of inorganic arsenic (iAs) in natural waters are arsenite (As3+) and arsenate (As5+). It is reported that marine algae are able to accumulate arsenic at higher levels than in the surrounding water. Therefore, marine algae can be used as the ecological indicators for arsenic contaminant in environment. In this study, in order to investigate the effect of iAs toxicity to macroalgae, Sarcodia suieae was treated with different concentrations of As3+ and As5+ for 5 days. Results showed that, the poor growth of S. suieae was detected when being exposed for 5 days to As3+ and As5+ with half inhibitory concentrations (IC50 value) of 401.5 ± 9.4 μg L-1 and 975.8 ± 13 μg L-1, respectively. Treatment of S. suieae with As3+and As5+significantly increased malondialdehyde (MDA) accumulation in a dose-dependent manner with the EC50 values of 146.4 and 249.1 μg L-1, respectively. On the other hand, to compare the toxicity of As3+ and As5+, S. suieae was treated at IC50 for 0, 1, 3, 6, 9, 12, 24, 72 and 120 h. In the As3+ treatment, the base of the S. suieae turned green at the 24 h, and finally the color of the S. suieae turned chartreuse on the 72 and 120 h. Results revealed that total chlorophyll、chlorophyll a、phycocyanin and phycoerythrin content were decreased in the thalli that being exposed to IC50 of As3+ and As5+ after 24 h. The contents of MDA and superoxide radical significantly increased after 12 h, whereas H2O2 content was significantly increased after 3 and 6 h. The antioxidative activity of superoxide dismutase (SOD) enzyme significantly increased after 12, 24, 72, and 120 h in the As3+ treatment, whereas increased catalase activity (CAT) was observed after 120 h of treatment. In the As5+ treatment, the activity of ascorbate peroxidase (APX) was significantly higher than that in the As3+ treatment after 120 h. In addition, glutathione (GSH) in the As3+ treatment was significantly higher than that in the As5+ treatment after 72 and 120 h. However, the ascorbic acid (AsA) content of S. suieae in the As5+ treatment was significantly higher than that in As3+ treatment after 9, 12, 24, 72 and 120 h. At the time points of 12, 24, 72 and 120 hours, As3+ treatment’s As3+ and As5+ content accounted for 80 %、85 %、91 %、90 % and 19 %、14 %、8 %、10 % of total inorganic arsenic; As5+ treatment’s As3+ and As5+ content accounted for 8 %、22 %、33 %、32 % and 91 %、77 %、66 %、67 % of the total inorganic arsenic, respectively. Obtained results indicated that among inorganic arsenic forms, S. suieae could accumulate As3+ higher than As5+ form when being exposed at the IC50. It is therefore concluded that As3+ may be more toxic than As5+, and S. suieae could modulate the antioxidant defense system to alleviate iAs-induced oxidative stress.
| Identifer | oai:union.ndltd.org:TW/106NPUS5086004 |
| Date | January 2018 |
| Creators | Lee, Po-Yi, 李勃毅 |
| Contributors | Wu, Tsung-Meng, 吳宗孟 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 101 |
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