Cellular damage associated with multiple mating inE. coli

Abstract

In crosses in which the ratio of Hfr to F- cells was varied it was found that with one group of Hfr strains the yield of recombinants increased linearly with donor concentration until the number of donor and recipient cells were approximately equal. With other Hfr strains marked deviations from linearity were observed at Hfr: F−ratios greater than 1:5 and in crosses with one particular F−strain the yield of recombinants actually decreased progressively as the Hfr concentration was raised beyond this value. The deviations from linearity observed with this group of strains have been shown to be due to damage to F−cells which mate simultaneously with several Hfr cells.

Conditionally lethal genes associated with bacterial plasmids

“…Two further lethal phenomena are connected with conjugative plasmids: lethal zygosis (Gross, 1963) and zygotic induction (Hayes, 1965) are associated with plasmid transfer by conjugation. Lethal zygosis was first observed as reduced viability of the recipients under conditions where F − bacteria were used in matings with an excess of Hfr donor cells (carrying F factor integrated into their chromosome).…”

Colicinogeny and related phenomena.

“…Recipients are killed only when mated with large numbers of donors (with a donor-to-recipient ratio of about 20:1), although there are bacteriostatic effects at lower multiplicities. The lethal effects of a high multiplicity of donors have been reported several times (5,85,213,421), and the mechanism has recently been investigated in detail by Skurray and Reeves (529,530,531).…”

Characterization of Lethal Zygosis Associated with Conjugation in Escherichia coli K-12

“…As the Hfr concentration was increased, the yield of recombinants (24) and the survival of F-cells (8) decreased. These observations led to the suggestion that the lethality observed could result from multiple conjugation involving simultaneous mating between one Fcell and several Hfr cells (8,24).…”

“…As the Hfr concentration was increased, the yield of recombinants (24) and the survival of F-cells (8) decreased. These observations led to the suggestion that the lethality observed could result from multiple conjugation involving simultaneous mating between one Fcell and several Hfr cells (8,24). There have been comments on the phenomenon in a number of reviews and reports (25,27,32,37,41), but no further detailed studies have been reported, and as a preliminary to examining recipient cells for metabolic changes associated with the lethal event, the phenomenon was characterized.…”