Osmotic stress in viable Escherichia coli as the basis for the antibiotic response by polymyxin B.
Cationic antimicrobial peptides, such as polymyxin B (PxB), below growth inhibitory concentration induce expression of osmY gene in viable E. coli without leakage of solutes and protons. osmY expression is also a locus of hyperosmotic stress response induced by common food preservatives, such as hypertonic NaCl or sucrose. High selectivity of PxB against Gram-negative organisms and the basis for the hyperosmotic stress response at sublethal PxB concentrations is attributed to PxB-induced mixing of anionic phospholipid between the outer layer of the cytoplasmic membrane with phospholipids in the inner layer of the outer membrane. This explanation is supported by PxB-mediated rapid and direct exchange of anionic phospholipid between vesicles. This mechanism is consistent with the observation that genetically stable resistance against PxB could not be induced by mutagenesis.
Oh
J T
JT
Department of Chemistry, University of Delaware, Newark 19716, USA.
Van Dyk
T K
TK
Cajal
Y
Y
Dhurjati
P S
PS
Sasser
M
M
Jain
M K
MK
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000096:biosynthesis*; D002352:Carrier Proteins / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects*; D029968:Escherichia coli Proteins; D015870:Gene Expression; D008826:Microbial Sensitivity Tests; D009997:Osmotic Pressure; D033902:Periplasmic Binding Proteins; D011112:Polymyxin B / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D033902:Periplasmic Binding Proteins; C074783:osmY protein, E coli; D011112:Polymyxin B