Colicin E1 blocks proline accumulation by membrane vesicles prepared from wild-type sensitive Escherichia coli. Two classes of mutant cells are unaffected by colicin. Vesicles from colicin-resistant strains are sensitive to colicin E1, whereas vesicles from colicin-tolerant strains are unaffected by colicin El. These results suggest that the colicin E1 receptor is on the cell membrane and that colicin-tolerant strains have altered membranes while colicin-resistant strains have altered cell walls.

Biological Transport↗

PubMed1970

Mechanism of colicin action: early events.

The kinetics and the temperature dependence of potassium loss from Escherichia coli cells treated with colicin K have been examined. At 37 C, after a single lethal hit, essentially all of the intracellular potassium is lost within the first few minutes of treatment. The initial rate of loss is linearly related to colicin concentration up to a multiplicity of 30. As the temperature is decreased over the range from 37 to 1 C, an increasing delay is seen in the initiation of potassium loss after colicin adsorption. This delay can be overcome by increasing colicin multiplicity and probably reflects an alteration of the cell membrane at these temperatures. A comparison of this effect with an apparently related effect of temperature on the action of irehdiamine A indicates that the delay may represent the inhibition of a transmission process occurring in the membrane.

Journal Article↗

PubMed1969

Evidence for two states of F pili.

The addition of phenethyl alcohol (PEA) to cultures of male strains of Escherichia coli rapidly prevents the adsorption of the male-specific bacteriophages f1 and f2 to the donor cells. The adsorption of f2 to F pili in cell-free preparations is unaffected by PEA. In a mating system, PEA alters the kinetics of gene transfer in minimal medium but not in broth. Sodium cyanide, azide, and iodoacetate also apparently inhibit f2 adsorption to cells but not to detached F pili. The phage adsorption inhibitory action of PEA is completely reversible in the presence of 100 mug of chloramphenicol per ml.

Adsorption↗

PubMed1967

Mechanism of action of phenethyl alcohol: breakdown of the cellular permeability barrier.

Phenethyl alcohol (PEA) caused Escherichia coli to take up greatly increased amounts of acriflavine, a compound to which healthy growing cells are impermeable. PEA also caused an increased rate of efflux (leakage) of cellular potassium under conditions which do not greatly alter the influx of potassium via the energy-dependent potassium pump. We therefore propose that the primary effect of PEA is a limited breakdown of the cell membrane. The inhibition of deoxyribonucleic acid synthesis and other cellular functions would then be secondary consequences of the alteration in the membrane structure.

Acridines↗