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Identification And Analysis Of Four ABC Transport Genes In Acidithiobacillus Ferrooxidans

Posted on:2012-01-05Degree:MasterType:Thesis
Country:ChinaCandidate:D M HouFull Text:PDF
GTID:2131330335989878Subject:Microbiology
Abstract/Summary:PDF Full Text Request
As an important bioleaching microorganism, Acidithiobacillus ferrooxidans have high resistance-capacities to many metal ions. It is very meaningful to study the resistance mechanisms in this extremophilic microorganism, and the results will be useful for lay a theoretical foundation to improve bioleaching ability of microorganism and upgrade the bioleaching technique.In our study, the tolerance on five heavy metal ions (Ni24\Mn2+ A13+,Zn2+,Cd2+)of the A. ferrooxidans DC were studied firstly. And four cation ATP-binding cassette (ABC) transporter genes of Acidithiobacillus ferrooxidans DC(At. ferrooxidans DC) were identified for the first time. After that, differential transcription of these genes during zinc ion stress were investigated by Reverse Transcription quantitative real-time PCR (RT-qPCR), and co-transcription of Afe2'435, Afe2436, Afe2437, Afe2438 were investigated by Reverse transcriptase PCR. At last, the further analyses of genes were analyzed by bioinformatics software.The results showed that:the tolerance on Ni2+, Mn2+,Al3+,Zn2+,Cd2+of At. ferrooxidans DC were 0.7 mol/L,0.4 mol/L,0.4 mol/L,0.6 mol/L, 0.75 mol/L, respectively.After blast by NCBI, the sequence of Afe2435, Afe2436, Afe2437, Afe2438 in At. ferrooxidans DC are the same as the sequence in At. ferrooxidans ATCC 23270.The expressions of the four ABC transporter genes were increased differently under zinc ion stress, and the expression of these genes up regulated higher while zinc ion concentration increasing. These results indicating that genes Afe2435, Afe2436, Afe2437, and Afe2438 were sensitive to zinc levels.With Reverse transcriptase PCR, it is known that genes Afe2435, Afe2436, Afe2437, Afe2438 were cotranscribed with each other, and probably they were in a single transcripton.Bioinformatics analysis showed that the proteins encode by Afe2435, Afe2436 were predicted to be permease proteins, whereas the protein encode by Afe2437 was a putative ATP-binding protein and Afe2438 encoded a putative periplasmic cation-binding protein.In conclusion, genes Afe2435, Afe2436, Afe2437, and Afe2438 constitute an ABC transporter in At. ferrooxidans DC, and this mechanism might be directly involved in zinc transport in Acidithiobacillus ferrooxidans DC. It is very important to zinc homeostasis in At. ferrooxidans DC.
Keywords/Search Tags:Acidithiobacillus ferrooxidans, ABC transporter, RT-qPCR, zinc stress, co-transcription
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