Fatty Acids Composition and Biofilm Production of Attenuated Salmonella typhimurium dam and seqA Mutants After Exposure to UV-C

Abstract

The goal of this work was the investigation of correlation between some peculiarities of membrane fatty acids composition, biofilm formation, and motility of dam and/or seqA mutants in Salmonella typhimurium bacterial cells and UV-C radiations. The exposure changed the fatty acids composition of dam and seqA/dam strains. Significant increase of unsaturated fatty acids was observed. Swarming and swimming were enhanced only in dam mutant and biofilm formation increased significantly in all tested strains after UV-C exposure. These results suggest that increased sensitivity toward UV-C rays in dam strains might be due to fatty acid alteration.

Effects of dam and seqA genes on biofilm and pellicle formation in Salmonella

“…In both dam and seqA mutants, the Dam methylase and SeqA proteins encoded by the respective genes probably perform these activities by altering the activity of the RNA polymerase or transcription factors in the promoter regions. It was previously determined that SeqA and Dam proteins might regulate fatty acid biosynthesis of Salmonella Typhimurium and membrane fluidity might cause changes in flagella and exopolysaccharide which are involved in the biofilm formation [23]. In our work, the changes observed in the biofilm formation of dam and seqA mutants may also lead to changes in the composition of the cell membranes due to these mutations.…”

“…It was shown in certain bacteria, such as Salmonella typhimurium, Escherichia coli and Acinetobacter baumannii, that biofilm formation is under epigenetic regulation [14,19,45]. However, there are a few articles describing the effect of dam methylation on biofilm formation in Salmonella [19,23]. Aya Castaneda et al [19] have found that DNA methylation in S. enteritidis upregulates the expression of biofilm production factors such as cellulose and curli by modifying the csgD expression.…”

“…Aya Castaneda et al [19] have found that DNA methylation in S. enteritidis upregulates the expression of biofilm production factors such as cellulose and curli by modifying the csgD expression. But, it was determined that seqA genes not be effective in biofilm formation [23].…”

“…Verification tests carried out using pBAD24 vector, mentioned above, yielded the same results when carried out with the seqA mutants. Several researchers determined the effect of dam and/or seqA mutations on the membrane composition of Salmonella Typhimurium [23,46]. In both dam and seqA mutants, the Dam methylase and SeqA proteins encoded by the respective genes probably perform these activities by altering the activity of the RNA polymerase or transcription factors in the promoter regions.…”

“…Chatti et al [22] have determined that virulence reduced significantly in the seqA mutants of S. typhimurium regarding wild type strain. In another study, conducted by the same investigators using S. typhimurium with dam and seqA mutants, it was determined that the membrane phospholipids undergo structural changes and the ability to produce biofilm in dam mutants, but wild-type and seqA mutants did not show significant alteration of Fatty acids (FAs) profile after UV-C treatment [23]. Authors concluded that the alteration in FAs composition of membrane leads to changes in several characteristics of strains, such as changes in the levels of biofilm formation and the motility of S. typhimurium strains.…”