Differential Expression Of Energy Metabolism Genes In Acidithiobacillus Ferrooxidans Under Different Energy Substance Cultures

Acidithiobacillus ferrooxidans, which are intensely studied as the type strain, have wide application such as mine leaching, enviromental remediation and coal biodesulfurizaiton. It obatains energy from mine leaching to drive the fixation of CO2and N2in atomosphere boosting itself to grow, which in reverse enhance the mine leaching. Acidithiobacillus ferrooxidans displays multiple pathways of energy metalbolism and have a strong adaptibility to extreme enviroment. Morever, flexiable and branched repiratory pathways and various reductant electron transport components have been found througth genome-wide bioinformatic screening. The research on the differential expression of the energy metabolism genes in Acidithiobacillus ferrooxidans under different energy substance cultures is proceeded.The research work mainly include three parts:the first part is about the growth discriptiopn of Acidithiobacillus ferrooxidans under ferrous iron, elmental sulfure, thiosulfate, sulfure coupled with ferric iron reduction under O2-limited condition and pyrite culture condition. The second part is differential gene transcription of25energy metalbolism genes conducted by the SYBR Green-based RT-qPCR. The third part is bioinformatic analysis of two proteins encoded by afe₁130and afe2408.The conclusion showed that Acidithiobacillus ferrooxidans with ferrous iron, elmental sulfure and pyrite culturing growed very well with relative high density, while it became dull and its shape became longer with the thiosulfate culturing. Under the O2-limited condition, the growth had seemly stopped, including energy metalbolism. Differential gene transcription indicated that AFE₁130, CycA2, Cycl_like, bo3complex, AFE₂761, AFE₁293and Mrp might play a role in RISC oxidation, while AFE₀652, Cyc2_like, Cyc2, CycAl, Cycl and Acop might play a role in ferrous oxidation.The fixation of carbon and nitrogen and biosynthesis metalbolsim was suggested more active in sulfur culturing than in ferrous. The terminal oxidase aa3and bd complex participated in the electron transfer both in ferrous and sulfure oxidation metalbolism. Potential NADH-quinol oxidoreductase and ATP synthase genes were both expressed with sulfure and ferrous culturing, but it transcribed more in sulfure culture condition, which would be furturer investigated. Bioinformatic analysis indicated that AFE₁130was an instable hydrophilic protein with a molecular weight10KDa, and belongs to the subclass ID of Class I of cytochorme c. AFE₁130was supposed to compose of5helixes with coil and to be achored on the inner membrane playing a role of electron transferring with a big raised hydrophobic area. while CyoA was predicted to be a stable protein with molecular weight36kDa and be composed of7helixes and11strands, which was devided into two domains, the N-terminal transmembrane and the C-terminal extrinsic domains, and to play a role in electron transfering between ubiquinol and O2as the potential cytochrome o oxidase subunit Ⅱ.