In the present study, we investigated the effect of exposure to A static magnetic field (SMF) on cell growth, viability, and gene expression of Salmonella enterica subsp. enterica serovar Hadar. Our results indicated that SMF exposure (200 mT, 13 hours) failed to alter cellular growth but induced a decrease of colony-forming units (CFU) between 3 and 6 hours followed by an increase from 6 to 9 hours. The analysis of the differential expression of rpoA, dnaK, katN, and 16S rRNA genes under SMF exposure (200 mT, 10 hours) showed that the expression level of the 16S rRNA mRNA remained stable during the exposure and can thus be used as a reference gene for the analysis on the differential gene expression of Salmonella Hadar. Interestingly, mRNAs of rpoA, katN, and dnaK genes were over-expressed following 10 hours of SMF exposure (200 mT). These data suggest a possible stress response of Salmonella Hadar to static magnetic field.
BackgroundSalmonella enterica serovar Hadar (S. Hadar) is a highly prevalent foodborne pathogen and therefore a major cause of human gastroenteritis worldwide. Outer membrane proteins whose production is often regulated by environmental conditions also play important roles in the adaptability of bacterial pathogens to various environments.ResultsThe present study investigated the adaptation of S. Hadar under the effect of acute static magnetic field exposure (200 mT, 9 h) and the impact on the outer membrane protein pattern. Via two-dimensional electrophoresis (2-DE) and LC-MS/MS spectrometry, we compared the proteome of enriched-outer membrane fraction before and after exposure to a magnetic field. A total of 11 proteins, displaying more than a two-fold change, were differentially expressed in exposed cells, among which 7 were up-regulated and 4 down-regulated. These proteins were involved in the integrity of cell envelope (TolB, Pal), in the response to oxidative stress (OmpW, dihydrolipoamide dehydrogenase, UspF), in the oxidative stress status (bacterioferritin), in virulence (OmpX, Yfgl) or in motility (FlgE and UspF). Complementary experiments associated the down-regulation of FlgE and UspF with an alteration of swarming, a flagella-driven motility, under SMF. Furthermore, the antibiotic disc diffusion method confirmed a decrease of gentamicin susceptibility in exposed cells. This decrease could be partly associated with the up-regulation of TolC, outer membrane component of an efflux pump. OmpA, a multifunctional protein, was up-regulated.ConclusionsSMF (200 mT) seems to maintain the cell envelope integrity and to submit the exposed cells to an oxidative stress. Some alterations suggest an increase of the ability of exposed cells to form biofilms.
The present study investigated the adaptation of Salmonella enterica subsp. enterica serovar Hadar to static magnetic field (SMF) exposure (200 mT, 9 h). The proteomic analysis provides an overview of potentially important cytosolic proteins that Salmonella needs to regulate to survive and adapt to magnetic stress. Via 2-dimensional electrophoresis and liquid chromatography tandem mass spectrometry, we compared cytosolic proteomes before and after exposure to magnetic field. A total of 35 proteins displaying more than a 2-fold change were differentially expressed in exposed cells, among which 25 were upregulated and 10 were downregulated. These proteins can be classified mainly into 6 categories: (i) proteins involved in metabolic pathways of carbohydrates, (ii) chaperones and proteins produced in response to oxidative stress, (iii) proteins involved in energy homeostasis, (iv) elongation factors (EF-Tu and EF-Ts), (v) proteins involved in motility, and (vi) proteins involved in molecules transport. Many of the presented observations could be explained, while some represent still-unknown mechanisms. In addition, this study reveals 5 hypothetical proteins. It seems that the stress response to SMF (200 mT) is essentially set up to avoid oxidative damages, with the overexpression of proteins directly involved in oxidative stress response and metabolic switches to counteract oxidative stress. Interestingly, several proteins induced under SMF exposure are found to overlap with those induced by other stresses, such as heat shock and starvation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.