title: Effect of combined long-term starvation and γ-irradiation on membrane fatty acids and cell surface hydrophobicity of Salmonella enterica serovar Typhimurium.
abstract: This study was carried out to explore the adaptive mechanisms of Salmonella enterica serovar Typhimurium, in particular the implication of fatty acids (FA) in the remodeling of membrane lipid composition to overcome the combined effects of long-term starvation and γ-irradiation stresses. In addition, cell surface hydrophobicity was also evaluated. The bacterial strains (control and starved) were treated with a nonlethal γ-irradiation dose of 0.5 kGy and sublethal doses of 1 kGy. Gas chromatography analysis showed that the FA composition of starved and γ-irradiated cells was modified. However starvation combined with γ-irradiation induced more modifications in the FA composition than γ-irradiation or starvation alone. Indeed, the unsaturated FA-to-saturated FA ratio decreased significantly for both strains compared with γ-irradiated cells, as main consequence of the cyclic FA formation. Our results showed that starvation, irradiation, or combined stresses significantly influenced the hydrophobicity, and this may have affected the virulence state of Salmonella Typhimurium cells. This study represents one of the few to demonstrate the modifications on bacterial membrane as a cellular response to survive to the ionizing radiation combined with long-term starvation stress.
authors.affiliation: Laboratory of Genetic, Biodiversity and Valorization of Bio-Resources, Higher Institute of Biotechnology, Monastir 5000, Tunisia.
authors.forename: Rihab
authors.initials: R
authors.lastname: Lagha
authors.affiliation: Laboratory of Genetic, Biodiversity and Valorization of Bio-Resources, Higher Institute of Biotechnology, Monastir 5000, Tunisia. Electronic address: fetyben@yahoo.fr.
authors.forename: Fethi
authors.initials: F
authors.lastname: Ben Abdallah
authors.affiliation: Higher Institute of Biotechnology, Sidi Thabet 2020, Tunisia.
authors.forename: Ahmed Salaheddine
authors.initials: AS
authors.lastname: Masmoudi
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000737:chemistry; D002849:Chromatography, Gas; D005227:Fatty Acids / Q000032:analysis*; D005720:Gamma Rays; D057927:Hydrophobic and Hydrophilic Interactions; D008563:Membrane Lipids / Q000032:analysis* / Q000502:physiology / Q000528:radiation effects; D012486:Salmonella typhimurium / Q000737:chemistry* / Q000502:physiology* / Q000528:radiation effects; D065288:Serogroup
chemical_list: D005227:Fatty Acids; D008563:Membrane Lipids
keywords: Salmonella Typhimurium; fatty acids; hydrophobicity; long-term starvation; γ-irradiation