Abstract
Acidithiobacillus ferrooxidans is a Gram-negative bacterium that obtains energy from the oxidation of ferrous iron or reduced sulfur compounds. In this bacterium, the proteins encoded by the rus operon are involved in electron transfer from Fe(II) to O2, and the first two proteins in this pathway also participate in the electron transfer pathway from Fe(II) to NAD(P). In this work we analyzed the expression, by real-time PCR, of the eight genes from the rus operon when A. ferrooxidans LR was grown in the presence of iron (control) and then kept in contact with chalcopyrite (CuFeS2) and covellite (CuS). A small decrease in rus operon gene expression was observed in the presence of chalcopyrite, while in the presence of covellite the expression of these genes showed a remarkable decrease. These results can be explained by the absence of ferrous iron in covellite. To explain the expression difference observed between the gene cyc1 and the gene rus, we investigated the information content presented at the Translation Initiation Site (TIS) of both genes. cyc1 showed a highly information content (8.4 bits) that can maximize translation, and rus showed a less favorable context (5.5 bits). Our hypothesis is that the energetic metabolism in A. ferrooxidans may be controlled at the transcriptional and posttranscriptional level by different mechanisms.
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Acknowledgments
This work was supported by a grant from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP 2005/51332-7). L.M.M.O. received a research fellowship from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). C.C. (06/54433-1) and F.C.R. (05/00139-2) received fellowships from FAPESP. D.J.M. (134062/2006-0) received a fellowship from CNPq. The authors thank Dr. O. Garcia Jr., for providing A. ferrooxidans strain LR.
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Carlos, C., Reis, F.C., Vicentini, R. et al. The rus Operon Genes Are Differentially Regulated When Acidithiobacillus ferrooxidans LR is Kept in Contact with Metal Sulfides. Curr Microbiol 57, 375–380 (2008). https://doi.org/10.1007/s00284-008-9208-7
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DOI: https://doi.org/10.1007/s00284-008-9208-7