探討hflC及相關基因在Pseudomonas sp.TeU 還原亞碲酸鹽之關聯性

微生物在金屬環境中常常能夠發展出抵抗這些有毒元素的機制，藉由從環境分離培養篩選出Pseudomonas sp. TeU，對於重金屬鎘及類金屬碲具有相當之耐受性，且具有還原碲之能力之菌株。在先前實驗中，利用跳躍子突變法我們得到一株較不具碲還原能力之突變株 (strain AU08)以及一株對鎘不具耐受性的突變株 (strain BU21)，並且鑑定出此兩株突變株被跳耀子Tn5破壞之基因分別為hflC以及金屬胜肽酶(metallopeptidase)之基因。本研究進一步將此菌株完整之hflC與metallopeptidase基因選殖並定序，進行蛋白質表現；並探討金屬胜肽酶對重金屬鎘耐受性之測試；另外以穿透式電子顯微鏡(TEM)觀察菌體與類金屬碲之作用累積情形。

關鍵字

還原碲；抗重金屬；假單胞菌屬

並列摘要

A Pseudomonas strain TeU resistant to tellurite (TeO32-) and cadmium (Cd2+) ions was isolated from heavy-metal contaminated sediments by enrichment. Transposon mutagenesis of strain TeU resulted in mutants exhibiting Cd2+ sensitivity (Strain BU21) and one with decreased ability to reduce tellurite (strain AU08). Genes encoding an HflKC complex and an putative metallopeptidase were identified to be associated with the bacterium’s ability for tellurite reduction and cadmium resistance, respectively. We have cloned and sequenced the hflC and metallopeptidase gene of strain TeU. Metallopeptidase gene of strain TeU was cloned and expressed in E. coli in order to investigate if the protein could improve the bacterium’s ability to resist cadmium.Transmission electron microcopy was also employed for to observe metal precipoitation when strain TeU grown in the medium containing tellurite.

並列關鍵字

Tellurite reduction ； heavy metal resistance ； Environmental Pseudomonas sp.

參考文獻

1.Guo H, L.S., Chen L, Xiao X, Xi Q, Wei W, Zeng G, Liu C, Wan Y, Chen J, He Y., Bioremediation of heavy metals by growing hyperaccumulaor endophytic bacterium Bacillus sp. L14. Bioresource Technology, 2010. 101(22): p. 8599-8605.

2.Fei Wanga, J.Y., Yang Sia, Huilun Chena, Mohammad Russela, Ke Chena, Yiguang Qiana, Gyula Zarayb and Emilia Bramantic, Short-time effect of heavy metals upon microbial community activity Journal of Hazardous Materials, 2009. 173(1-3): p. 7.

4.Romany N. N. Abskharon, S.H.A.H., Mohammad Humayun Kabir, Syed Abdul Qadir, Sanaa M. F. Gad El-Rab and Myeong-Hyeon Wang, The role of antioxidants enzymes of E. coli ASU3, a tolerant strain to heavy metals toxicity, in combating oxidative stress of copper microbology and biotechnology, 2010. 26(2): p. 241-247.

5.Avery, Simon V., Review,Molecular targets of oxidative stress. Biochemical Journal, 2011. 434(2): p. 201-210.

6.Xiao Xiao, S.L., Guangming Zeng, Wanzhi Wei, Yong Wan, Biosorption of cadmium by endophytic fungus (EF) Microsphaeropsis sp. LSE10 isolated from cadmium hyperaccumulator Solanum nigrum L. Bioresour Technol, 2010. 101(6): p. 1668-74.

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