Differential proteome analysis of a selected bacterial strain isolated from a high background radiation area in response to radium stress

The present study describes the response of a bacterial strain, isolated from a hot spring in an area with the highest levels of natural radiation, under radium (Ra-226) stress. The bacterium has been characterized as a novel and efficient radium biosorbent and identified as a variant of Serratia marcescens by biochemical tests and molecular recognition. In order to gain insights into key cellular events that allow this strain to survive and undergo Ra-226 adaptation and biosorption, the strain was tested under two experimental conditions of 1000 and 6000 Bq Ra-226 stress. A proteomic approach involving two-dimensional polyacrylamide gel electrophoresis and mass spectrometry was used to identify the differentially expressed proteins under Ra-226 stress. Functional assessment of identified proteins with significantly altered expression levels revealed several mechanisms thought to be involved in Ra-226 adaptation and conferring resistant phenotype to the isolate, including general stress adaptation, anti-oxidative stress, protein and nucleic acid synthesis, energy metabolism, efflux and transport proteins. It suggests that this strain through evolution is particularly well adapted to the high background radiation environment and could represent an alternative source to remove Ra-226 from such areas as well as industrial radionuclide polluted wastewaters. (C) 2012 Elsevier B.V. All rights reserved.