Title page for etd-0009117-160845


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URN etd-0009117-160845
Author Chia-Sheng Chiu
Author's Email Address No Public.
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Department Department of Oceanography
Year 2016
Semester 1
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Environmental Stress Tolerance of Aerial Microalgae from Dongsha Island and Their Potential Mechnaisms
Date of Defense 2016-10-06
Page Count 48
Keyword
  • drought stress
  • UV stress
  • heat stress
  • low temperature stress
  • microalgae
  • Abstract It has been reported that microalgae can be found in the air, but aerial microalgae have not been investigated seriously. Microalgae lives in watery and moist environments. When dispersed in the air, these cells have to tolerate drought stress, UV radiation, and either high or low temperature in order to survive. For the cells that can survive these environmental stresses, they have a chance to quickly expand their habitats by using wind as a means to spread. To investigate what microalgal species can survive these stresses and what mechanisms they use, four new species of aerial microalgae were isolated on Dongsha Island in South China Sea in the seasonal northeast wind. Based on 18S rDNA and ITS sequences and morphological analyses, the four new species were named Scenedesmus sp. DSA1, Coelastrella sp. DSA2, Coelastrella sp. DSA3 and Desmodesmus sp. DSA6, which are members in the family Scenedesmaceae. Their tolerance to environmental stresses were assessed, and the potential mechanisms were studied. The cell wall thickness of the four species and two controls positively correlates to their UV tolerance. The tolerance to drought and low temperature of DSA1, DSA2 and DSA3 is extremely high. Freeze-drying (lyophilization) could not kill these cells, and this phenomenon could not be explained by water content in the dried cells or their antioxidation capacities in these cells. Thermotolerance of DSA1, DSA2 and DSA6 is among the highest in the literature. These cells in liquid culture could survive at 50 ℃. The carotenoid levels in the stressed DSA2 and DSA3 cells were higher than in the DSA1 cells, followed by that in the DSA6 cells. These carotenoids contained astaxanthin, adonirubin, lutein,canthaxanthin, and -carotene analyzed by using HPLC.
    Advisory Committee
  • Yi-Min Chen - chair
  • Yu-Chi Chen - co-chair
  • Ching-Nen Chen - advisor
  • Files
  • etd-0009117-160845.pdf
  • Indicate in-campus at 5 year and off-campus access at 5 year.
    Date of Submission 2017-01-09

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