Please use this identifier to cite or link to this item: https://hdl.handle.net/2440/11650
Citations
Scopus Web of ScienceĀ® Altmetric
?
?
Type: Journal article
Title: The Salmonella typhi melittin resistance gene pqaB affects intracellular growth in PMA-differentiated U937 cells, polymyxin B resistance, and lipopolysaccharide.
Author: Baker, S.
Gunn, J.
Morona, R.
Citation: Microbiology, 1999; 145(2):367-378
Publisher: MICROBIOLOGY SOC
Issue Date: 1999
ISSN: 1350-0872
1465-2080
Abstract: Salmonella typhi is the causative agent of typhoid fever in humans. A cell-culture based assay involving the human monocyte macrophage cell line U937 has been developed to examine S. typhi invasion and survival. An S. typhi PhoP- (null) mutant was shown to be restricted in net growth in phorbol myristate acetate (PMA) differentiated U937 (PMA-U937) cells, and an S. typhi PhoPc (constitutive) mutant showed a defect in invasion. Neither of the phoP/Q mutants were growth impaired in HeLa cells, however the PhoPc mutant was impaired in invasion. As opposed to what was found for S. typhi, Salmonella typhimurium wild-type, PhoP- and PhoPc mutants grew equally well in PMA-U937 cells, indicating that the PhoP(-)-mediated net growth restriction in the PMA-U937 cells was S. typhi specific. An S. typhi mutation, pqaB::MudJ, recently shown to be a PhoP-activated locus, was shown to have a net growth defect in PMA-U937 cells. Sequencing of the S. typhipqaB gene revealed it had 98% identity to the fifth gene in a S. typhimurium PmrA/B regulated operon necessary for 4-aminoarabinose lipid A modification and polymyxin B resistance. The pqaB locus was regulated by PmrA/B (whose activity is modulated by PhoP-PhoQ) and the pqaB transposon mutant was sensitive to polymyxin B. The lipopolysaccharides (LPS) of S. typhi and S. typhimurium wild-type, PhoP- and PhoPc mutants, were compared by SDS-PAGE and silver staining. Differences in the LPS profile between the two Salmonella species were observed, and shown to be affected differently by the PhoPc mutation. Additionally, the pqaB::MudJ mutation affected S. typhi LPS. The effects on LPS may have ramifications for the difference between S. typhi and S. typhimurium infection of hosts.
Keywords: Hela Cells
U937 Cells
Macrophages
Humans
Salmonella typhi
Salmonella typhimurium
Tetradecanoylphorbol Acetate
Polymyxin B
L-Lactate Dehydrogenase
Lipopolysaccharides
Arabinose
Lipid A
DNA Transposable Elements
Melitten
Anti-Bacterial Agents
Drug Resistance, Microbial
Virulence
Gene Expression Regulation, Bacterial
Molecular Sequence Data
DOI: 10.1099/13500872-145-2-367
Appears in Collections:Aurora harvest 7
Microbiology and Immunology publications

Files in This Item:
There are no files associated with this item.


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.