(中南大學(xué) 資源加工與生物工程學(xué)院 教育部生物冶金重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083)
摘 要: 嗜酸氧化亞鐵硫桿菌(Acidithiobacillus ferrooxidans，At. ferrooxidans)廣泛應(yīng)用于銅、鋅、錳和鎘等金屬離子的生物浸出，浸出液中含有大量的金屬離子。研究At. ferrooxidans DC菌株在金屬離子脅迫下金屬轉(zhuǎn)運(yùn)基因的相對(duì)表達(dá)，測(cè)定At. ferrooxidans DC對(duì)Mn2+、Zn2+和Cd2+的最大耐受濃度。應(yīng)用RT-qPCR技術(shù)分析At. ferrooxidans DC中4個(gè)金屬轉(zhuǎn)運(yùn)基因(afe_0671、afe_0674、afe_1143和afe_1144)在Mn2+、Zn2+和Cd2+脅迫下的差異表達(dá)。利用BLAST等生物學(xué)軟件對(duì)各基因及其編碼的蛋白進(jìn)行生物信息學(xué)分析。結(jié)果表明：At. ferrooxidans DC菌株對(duì)Mn2+、Zn2+和Cd2+的最大耐受濃度分別是0.38、0.18和0.08 mol/L；在Mn2+、Zn2+和Cd2+脅迫下，目標(biāo)基因的表達(dá)均上調(diào)，且隨著金屬離子濃度的增加，上調(diào)倍數(shù)升高；生物信息學(xué)分析表明目標(biāo)基因編碼為與金屬轉(zhuǎn)運(yùn)相關(guān)的膜蛋白；在At. ferrooxidans DC中，目標(biāo)基因編碼的蛋白與Mn2+、Zn2+和Cd2+的轉(zhuǎn)運(yùn)密切相關(guān)。
關(guān)鍵字: 嗜酸氧化亞鐵硫桿菌；金屬轉(zhuǎn)運(yùn)基因；Zn2+；Cd2+；Mn2+；RT-qPCR；差異表達(dá)
（Key Laboratory of Biometallurgy of Ministry, Education, School of Resources Processing and Bioengineering,
Central South University, Changsha 410083, China）
Abstract:At. ferrooxidans were widely used in bioleaching of copper, zinc, manganese, cadmium, and so on. There were large quantities of metal ions in the bioleaching extract. The relative expression of metal transport genes was investigated when At. ferrooxidans were cultured in the presence of metal ions, the foundation for studying the molecular mechanism of At. ferrooxidans tolerated high concentration of metal ions was established. The tolerance levels of At. ferrooxidans DC to Mn2+, Zn2+ and Cd2+ were determined. RT-qPCR were employed to study the differential expression of four metal transport genes (afe_0671, afe_0674, afe_1143 and afe_1144) in At. ferrooxidans strain DC cultured in the presence of Zn2+, Mn2+ and Cd2+. And then, the target genes and proteins encoded by the four genes were analyzed by BLAST bioinformatics software. The results show that the tolerance levels of At. ferrooxidans DC to the stress of Mn2+, Zn2+ and Cd2+ are 0.38, 0.18 and 0.08 mol/L, respectively. The differential expressions of the target genes increase under the stress of Mn2+, Zn2+ and Cd2+. The bioinformatics analysis shows that the proteins encoded by target genes are membrane proteins involving in metal transport. These results suggest that the proteins encoded by target genes may be involved in Mn2+, Zn2+ and Cd2+ transport in At. ferrooxidans DC.
Key words: At. ferrooxidans; metal tranport genes; Zn2+; Mn2+; Cd2+; RT-qPCR; differential expression
