Comparative study of redox stress response in the acidophilic bacteria Leptospirillum ferriphilum and Acidithiobacillus ferrooxidans
Leptospirillum ferriphilum and Acidithiobacillus ferrooxidans are chemolithoautotrophic bacteria that obtain their energy from the oxidation of ferrous ion. Both microorganisms are important for bioleaching of sulphide ores. Acid bioleaching environments contain high levels of iron and heavy metals, which can increase the generation of reactive oxygen species (ROS) and induce oxidative stress in these microorganisms. Additionally, ferrousoxidizing bacteria have high respiratory rates that could also stimulate the generation of ROS. In this work, we compared the tolerance of L. ferriphilum and A. ferrooxidans to Fe + and the oxidizing agents H2O2 , K2Cr04 and paraquat. We evaluated growth, survival, ROS generation and oxidative damage of membranes (lipoperoxidation) after the cells were treated with different concentrations of these compounds. In addition, by means of a bioinformatic approach with the genomic sequences available in public databases we predicted and compared the molecular mechanisms involved in the oxidative stress response of both microorganisms. We observed that L. ferriphilum has higher tolerance to Fe3+ compared to that of A. ferrooxidans. However, tolerance of each bacterium to H2 02, K2 CrO4 and paraquat was similar. However, after the treatment with the oxidizing agents the intracellular levels of generated ROS were significantly higher in L. ferriphilum than in that A. ferrooxidans. Interestingly, in L. ferriphilum the levels of lipoperoxidation were significantly lower than that in A. ferrooxidans for all the tested compounds. Altogether, these results suggest that the antioxidant protection systems from L. ferriphilum could be focused on repair the cellular damage rather than the degradation of ROS. These finding are in agreement with bioinformatic predictions that suggest that a differential set of antioxidant functions should be present in these bacteria.
Leptospirillum ferriphilum Acidithiobacillus ferrooxidans oxidative stress, bioleaching
Andres Cortes Rodrigo Flores Javiera Norambuena Juan Pablo Cardenas Raquel Quatrini Renato Chavez Omar Orellana Gloria Levican
Departamento de Biologfa, Fac. de Quimica y Biologia, Universidad de Santiago de Chile, Chile Centra de Bioinformdtica y Biologfa Genomica, Fundacion Ciencia para la Vida. Santiago, Chile Programa de Biologia Celular y Molecular, ICBM, Fac. de Medicina, Universidad de Chile, Chile
国际会议
The 19th International Biohydrometallurgy Symposium(第19届国际生物湿法冶金大会 IBS2011)
长沙
英文
354-357
2011-09-18（万方平台首次上网日期，不代表论文的发表时间）