台灣地熱區抗輻射嗜熱菌之研究

Studies of Radioresistant Thermophilic Bacteria from Geothermal Areas in Taiwan

許嘉如(Chia-Ju Hsu)

指導教授 ： 蔡珊珊

國立臺灣大學/生命科學院/植物科學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.02997

摘要

台灣地熱區的嗜熱菌種類極為豐富，不同菌種其生活形態及適應環境的能力亦有所區別。從演化的角度來看，最早發現的嗜熱菌 Thermus 與目前研究最多的抗輻射菌種 Deinococcus radiodurans 具高度親緣關係，故在嗜熱菌中是否有抗輻射菌株的存在是一個具潛力且值得探討的課題。先前的研究，在溫泉環境中已發現具有輻射抗性嗜熱菌的存在；本研究是利用台灣各地的溫泉樣本，經初步輻射處理後篩選當中具輻射抗性之嗜熱菌，並利用生理生化形態及遺傳學之分析法，將台灣地熱區所分離出之具輻射抗性的菌種加以鑑定，分別屬於七屬：包括Deioncoccus spp.、Rubrobacter spp.、Meiothermus spp.、Bacillus spp.、Aneurinibacillus spp.、Anoxybacillus spp. 及Paenibacillus spp.。再由七屬共挑選 20 株菌株，分別測試各屬菌株在不同逆境下 ( 迦瑪射線處理、紫外線處理、金屬逆境及過氧化氫逆境 ) 的抗性。結果發現，本研究所分離出的 20 株菌株對迦瑪射線及紫外線均有極高的抗性，且對過氧化氫的抗性也極高；但是在金屬逆境下，對金屬的抗性與可抗輻射的特性並無明顯相關。此外，本實驗所分離出的抗輻射嗜熱菌中，其中四屬包括 Meiothermus spp.、Aneurinibacillus spp.、Anoxybacillus spp. 及 Paenibacillus spp.，在以前的研究中並未發現具輻射抗性的菌株；證明在台灣地熱溫泉區的嗜熱性細菌具有豐富的多樣性，且抗輻射嗜熱菌亦廣泛的存在台灣地熱溫泉區中。

關鍵字

嗜熱菌 ； 輻射抗性

並列摘要

There are many different kinds of thermophilic bacteria living in the geothermal environment around Taiwan. According to the phylogenetic analysis, the well documented radiation resistant Deinococcus radiodurans and thermophilic bacteria Thermus spp. may come from same ancestor. Several thermophilic bacteria with extremely gamma-radiation resistance had been reported from hot spring environment recently. The objective of this study is to investigate thermophilic bacteria also carrying radio-resistant ability from hot springs in Taiwan. Two hundred and three thermophiles were isolated from 72 hot springs in Taiwan after gamma radiation treatment of the samples. According to 16S rDNA sequence analysis, these isolates were grouped into 7 genera: Deioncoccus spp., Rubrobacter spp., Meiothermus spp., Bacillus spp., Aneurinibacillus spp., Anoxybacillus spp. and Paenibacillus spp. Twenty strains were selected for further studies. Besides the morphological, biochemical and genetic analyses of these twenty isolates, the stress conditions including γ and UV radiation, heavy metal ﹝Cd(NO3)2 & HgCl2﹞ as well as hydrogen peroxide treatment are also determined. The results showed that most of the isolates were extremely resistant to γ-radiation, UV light as well as hydrogen peroxide. However, there are no evidence to show that these thermophilic radioresistant bacteria also have the ability to resistant heavy metal. This is the first report that Meiothermus spp., Aneurinibacillus spp., Anoxybacillus spp. and Paenibacillus spp. have the ability to resist radiation.

並列關鍵字

Thermophilic Bacteria ； Radioresistant

參考文獻

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