title: Metal resistance-related genes are differently expressed in response to copper and zinc ion in six Acidithiobacillus ferrooxidans strains.
abstract: Metal resistance of acidophilic bacteria is very significant during bioleaching of copper ores since high concentration of metal is harmful to the growth of microorganisms. The resistance levels of six Acidithiobacillus ferrooxidans strains to 0.15 M copper and 0.2 M zinc were investigated, and eight metal resistance-related genes (afe-0022, afe-0326, afe-0329, afe-1143, afe-0602, afe-0603, afe-0604, and afe-1788) were sequenced and analyzed. The transcriptional expression levels of eight possible metal tolerance genes in six A. ferrooxidans strains exposed to 0.15 M Cu(2+) and 0.2 M Zn(2+) were determined by real-time quantitative PCR (RT-qPCR), respectively. The copper resistance levels of six A. ferrooxidans strains declined followed by DY26, DX5, DY15, GD-B, GD-0, and YTW. The zinc tolerance levels of six A. ferrooxidans strains exposed to 0.2 M Zn(2+) from high to low were YTW > GD-B > DY26 > GD-0 > DX5 > DY15. Seven metal tolerance-related genes all presented in the genome of six strains, except afe-0604. The metal resistance-related genes showed different transcriptional expression patterns in six A. ferrooxidans strains. The expression of gene afe-0326 and afe-0022 in six A. ferrooxidans strains in response to 0.15 M Cu(2+) showed the same trend with the resistance levels. The expression levels of genes afe-0602, afe-0603, afe-0604, and afe-1788 in six strains response to 0.2 M Zn(2+) did not show a clear correlation between the zinc tolerance levels of six strains. According to the results of RT-qPCR and bioinformatics analysis, the proteins encoded by afe-0022, afe-0326, afe-0329, and afe-1143 were related to Cu(2+) transport of A. ferrooxidans strains.
authors.affiliation: Key Lab of Biometallurgy of Ministry of Education of China, School of Minerals Processing and Bioengineering, Central South University, No. 932 Lushan South Road, Yuelu District, Changsha, 410083, Hunan Province, People's Republic of China.
authors.forename: Xueling
authors.initials: X
authors.lastname: Wu
authors.forename: Zhenzhen
authors.initials: Z
authors.lastname: Zhang
authors.forename: Lili
authors.initials: L
authors.lastname: Liu
authors.forename: Fanfan
authors.initials: F
authors.lastname: Deng
authors.forename: Xinxing
authors.initials: X
authors.lastname: Liu
authors.forename: Guanzhou
authors.initials: G
authors.lastname: Qiu
mesh_terms: D042763:Acidithiobacillus / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000235:genetics; D003300:Copper / Q000633:toxicity*; D024881:Drug Resistance, Bacterial; D020869:Gene Expression Profiling; D007477:Ions / Q000633:toxicity; D026901:Membrane Transport Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D015032:Zinc / Q000633:toxicity*
chemical_list: D001426:Bacterial Proteins; D007477:Ions; D026901:Membrane Transport Proteins; D003300:Copper; D015032:Zinc