Ionome analysis of of Salmonella mutants by Inductively coupled plasma mass spectrometry (ICP-MS)

In many Gram-negative bacteria, the stress sigma factor of RNA polymerase, σS/RpoS, remodels global gene expression to reshape the physiology of quiescent cells and ensure their survival under non-optimal growth conditions. In the foodborne pathogen Salmonella enterica serovar Typhimurium, σS is also required for biofilm formation and virulence.

We have previously shown that a ΔrpoS mutation affects the Salmonella ionome. Indeed, inductively coupled plasma mass spectrometry analyses have unraveled a significant effect of the ΔrpoS mutation on the cellular concentration of manganese, magnesium, cobalt and potassium, suggesting that σS controls fluxes of ions that might be important for the fitness of quiescent cells (Metaane et al. 2022, PLoS ONE 17(3): e0265511).

Study: These findings prompted us to evaluate the impact on the Salmonella ionome of deletions of genes encoding  the Salmonella Mn2+ transporters (sitABCD and mntH), the Co2+ transporter (cbiMNQO operon) and small proteins of unkown function (yqaE and yqjDEK) that accumulate in quiescent Salmonella under the tight control of σS (Levi-Meyrueis et al. PloS one. 2014; 9(5):e96918, Lago et al. Scientific reports. 2017; 7(1):2127 and Metaane et al. 2022, PLoS ONE 17(3): e0265511).

Material and Methods: Cell-associated contents of several elements were measured by inductively coupled plasma mass spectrometry (ICP-MS) as previously described in Metaane et al 2022 PLoS ONE 17(3): e0265511.Dried cell pellets were prepared by V. Monteil and F. Norel (Institut Pasteur, Université de Paris, CNRS UMR3528, Biochimie des Interactions Macromoléculaires, F-75015, Paris, France). Cell-associated contents of several elements were measured by S. Ayrault and L. Bordier (ICP-MS platform, Laboratoire des Sciences du Climat et de l’Environnement, LSCE/IPSL, CEA-CNRSUVSQ,Université Paris-Saclay, 91191, Gif-sur-Yvette, France)