Proteomic Approach of Adaptive Response to Arsenic Stress in Exiguobacterium sp. S17. An Extremophile Strain Isolate from High Altitude Andean Lake Stromatolite

Abstract

North West of Argentina is particularly rich in wetlands located in the Puna in a range of altitude of 3,600 to 4,600 m above sea level. Most of these high-altitude Andean lakes are inhospitable areas suffering from extreme conditions such as high content of toxic elements particularly Arsenic. Exiguobacterium sp. S17, isolated from stromatolite in Laguna Socompa, showed tolerance to high arsenic concentration. The assays revealed that this strain was able to growth in presence of 10mM and 150mM of As(III) and As(V) respectively. To understand the mechanisms implicated in Exiguobacterium sp. S17 tolerance arsenic to proteomic approach was conducted. Comparative proteomic analyses of S17 arsenic exposed and unexposed to reveal that 25 spots were differentially expressed. Identification of proteins was performed by MALDI-TOF/MS, and the results obtained revealed that proteins involved in energy-metabolism, stress, transport, and in proteins synthesis were expressed under arsenic stress. To our knowledge, this work represents the first proteomic study of arsenic tolerance in an Exiguobacterium strain.