Response of moderately halophilic bacterium Salinicola socius strain SMB35^T cells to oxidative stress induced by the action of hydrogen peroxide

¹ Institute of Ecology and Genetics of Microorganisms UB RAS – branch of the Perm Federal Research Center of the UB RAS, 614081 Perm, Russia
² Institute of Technical Chemistry UB RAS – branch of the Perm Federal Research Center of the UB RAS, 614013 Perm, Russia

¹ Corresponding author: ludaananyina@mail.ru

Abstract

The aim of the present study was to investigate the response of Salinicola socius strain SMB35^T cells to oxidative stress modelled by the introduction of hydrogen peroxide into the medium. It was found that when hydrogen peroxide was added to the cell suspension to a final concentration of 25 μM, a slight decrease in biomass was observed, while the addition of hydrogen peroxide to a concentration of 25 mM resulted in a significant decrease in biomass. Since a statistically significant decrease in biomass was noted upon exposure to hydrogen peroxide at a concentration of 25 mM, the amount of compatible solutes in cells of Salinicola socius strain SMB35^T after exposure to hydrogen peroxide was evaluated. Cell extracts were studied by proton magnetic resonance spectroscopy. Under conditions of oxidative stress, a trend towards a decrease in the amount of ectoine was observed, and the pool of its precursor – N(4)-acetyl-L-2,4-diaminobutyrate - decreased by a factor of 2.1. Oxidative stress significantly affected the intracellular amount of glutamate; its content decreased by 5.6 times. It was found that after incubation with H₂O₂, the amount of alanine and valine in the cells reduced. In response to oxidative stress, a trend towards increasing trehalose content in cells was observed, but its amount was 8.7 times less than that of ectoine.