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Updated: Sep 20, 2026

Isolation and Chemical Characterization of Lipid A from Gram-negative Bacteria
Published on: September 16, 2013
Effect of EDTA on Salmonella enterica serovar Typhimurium involves a component not assignable to lipopolysaccharide
H-L Alakomi1, M Saarela1, I M Helander2,1
1VTT Biotechnology, PO Box 1500, FIN-02044 VTT, Espoo, Finland.
Abstract:
The effect of EDTA on Salmonella enterica serovar Typhimurium was studied in different growth phases with cells grown with or without Ca(2+) and Mg(2+) supplementation. EDTA affected the outer membrane much more strongly in the early exponential phase than in the mid- or late exponential phase, as indicated by uptake of 1-N-phenylnaphthylamine (a nonpolar hydrophobic probe, M(r) 219), and detergent (SDS) susceptibility. This effect was, however, not paralleled by LPS release (determined by measuring LPS-specific fatty acids or 14C-labelled LPS in cell-free supernatants, per a standardized cell density), which remained unchanged as a function of the growth curve. The conclusion from these results is that in the early exponential phase the effect of EDTA in S. enterica involves a component that is independent of LPS release.
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