Effect of bile on the cell surface permeability barrier and efflux system of Vibrio cholerae.
Gram-negative bacteria are inherently impermeable to hydrophobic compounds, due to the synergistic activity of the permeability barrier imposed by the outer membrane and energy dependent efflux systems. The gram-negative, enteric pathogen Vibrio cholerae appears to be deficient in both these activities; the outer membrane is not an effective barrier to hydrophobic permeants, presumably due to the presence of exposed phospholipids on the outer leaflet of the outer membrane, and efflux systems are at best only partially active. When V. cholerae was grown in the presence of bile, entry of hydrophobic compounds into the cells was significantly reduced. No difference was detected in the extent of exposed phospholipids on the outer leaflet of the outer membrane between cells grown in the presence or absence of bile. However, in the presence of energy uncouplers, uptake of hydrophobic probes was comparable between cells grown in the presence or absence of bile, indicating that energy-dependent efflux processes may be involved in restricting the entry of hydrophobic permeants into bile grown cells. Indeed, an efflux system(s) is essential for survival of V. cholerae in the presence of bile. Expression of acrAB, encoding an RND family efflux pump, was significantly increased in V. cholerae cells grown in vitro in the presence of bile and also in cells grown in rabbit intestine.
Biophysics Division, Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Calcutta 700 032, India.
Arpita
A
Chatterjee
Sohini
S
Chaudhuri
Gargi
G
Saha
Satadeepa
S
Gupta
Rukhsana
R
Chowdhury
D015057:1-Naphthylamine / Q000031:analogs & derivatives* / Q000378:metabolism; D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism; D001647:Bile Acids and Salts / Q000494:pharmacology*; D001692:Biological Transport; D002463:Cell Membrane Permeability / Q000187:drug effects*; D003470:Culture Media; D005456:Fluorescent Dyes / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D007082:Ileum / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D009675:Novobiocin / Q000378:metabolism / Q000494:pharmacology; D011817:Rabbits; D014734:Vibrio cholerae / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology
D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D001647:Bile Acids and Salts; D003470:Culture Media; D005456:Fluorescent Dyes; D009675:Novobiocin; C005444:N-phenyl-1-naphthylamine; D015057:1-Naphthylamine