Effect of protonophore on growth of Escherichia coli

Abstract

When 20 microM of carbonyl cyanide-m-chlorophenyl hydrazone (CCCP) were added to a M medium containing glucose as an energy source at pH 7.6, the Escherichia coli K12 strain 3301 was able to grow, whereas on the medium containing NaCl above 200 mM, the growth was remarkably suppressed by the addition of 20 microM CCCP. Furthermore, when glucose was replaced by either glycerol or lactate as an energy source, no growth occurred in the presence of 20 microM of CCCP. When glycerol was used as a substrate, O2 consumption by whole cells was observed in the presence of 20 microM of CCCP, but not in the case of lactate. We found that 14C-lactate uptake was completely inhibited by the addition of 20 microM of CCCP. The cells, which were incubated for 24 h on a M medium containing glucose in the presence of 20 microM of CCCP produced many more organic acids (mainly, acetate and lactate) than was the case in its absence. It appears that the influx process of external lactate when this was added as an energy source, was completely inhibited by addition of CCCP (20 microM), but the efflux process of lactate that was produced by glycolysis, was not influenced by this protonophore. On the other hand, it is suggested that on the hyposalts medium, a proton motive force (pmf) is not necessary for the growth of the strain 3301, whereas pmf is necessary for growth to occur.

Compensatory role of PspA, a member of the phage shock protein operon, in rpoE mutant Salmonella enterica serovar Typhimurium

“…Interestingly, despite a significant reduction in Δψ, rpoE mutant Salmonella remains capable of growth. Under some laboratory conditions, even CCCP‐induced dissipation of PMF does not necessarily inhibit E. coli growth (Kinoshita et al ., 1984; Nakano and Onoda, 1989), although we found CCCP to be lethal for rpoE or pspA mutant Salmonella .…”

Xylan Deconstruction by Environmental Bacterium Caulobacter crescentus

“…This effect was not observed for CB15 xylose minimal media culture induced with CCCP, which might be due to the presence of OprB protein on the outer membrane of CB15 that allows diffusion of xylose into the cell across the outer membrane as OprB has been shown to transport wide range of hydrophilic molecules including different monosaccharides [15,43]. Presence of CCCP in bacterial cultures has been shown to slow down the growth [44]. For larger substrate transportation, C. crescentus may rely heavily on TBDTs and impairment of proton motive force that is necessary for the function of CBM thus upon cleavage of glycosidic linkage it may be released into the environment as shown in that study [15].…”

Uncoupler-resistant mutants of bacteria.

“…Under certain conditions, E. coli can grow in the presence of an uncoupler and in the apparent absence of a AIxH+ (56,75). A fermentable carbon source and an extracellular pH close to 7.5 are generally required.…”