Changes of ROS and mitochondria biogenesis during zebrafish embryonic development

• Main Authors: Jen-Kuei Chiu, 邱仁奎
• Other Authors: Chin-Hwa Hu
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/89588419417985314711

碩士 === 國立臺灣海洋大學 === 生物科技研究所 === 100 === Free radicals are formed with an atom or molecule containing unpaired electron. The most abundant free radical species is reactive oxygen species (ROS) that are produced during anaerobic metabolism. The free radical theory of development hypothesizes that an adequate ROS production make cell toward differentiation, but excess ROS production threatens cell surviving. Here I have examined the ROS accumulation and mitochondria biogenesis in zebrafish embryos by CM-H2DCFDA and mitoTracker staining, respectively. I have revealed that ROS is produced and accumulated in the liver and intestine whereas the mitochondria biogenesis is increased in the epidermal ionocytes during development. Mitochondria-enriched ionocytes appear in the epidermis at 2 dpf stage, where massive amount of ATP are required for ion exchange. Surprisingly, no ROS accumalation was observed in these mitochondria-enriched ionocytes, suggesting that ionocytes probably are equipped with specific system to cleanup exceeded ROS production during aerobic respiration. Oxidative stress in hydrogen peroxide solution only slightly increased ROS accumulation, but promoted massive mitochondria biogenesis. Conversely, reductive stress in N-acetyl cysteine did not change ROS accumalation and mitochondria biogenesis, but only delayed ROS accumulation in gastrointestinal tract. Knockdown superoxide dismutase 1 (sod1) and catalase (cat) only mildly increased ROS production, but induced enormous mitochondria biogenesis. In summary, this study revealed that ROS accumulation and mitochondria biogenesis are not correlated to each other in the developing embryos. Oxidative stress or knockdown of sod1, cat prompted massive mitohondira biogenesis in the embryos, but did not caused ROS accumalation. The influence and mechanism of ROS production and mitochondria biogenesis during embryonic development need further investigation in the future.