Conjugation follows a type II Functional response [Dataset]

<b>A)</b> Scheme showing the conjugative transmission of a plasmid (red circle) in a population of susceptible cells under Density-Dependent Transmission (DDT). In this regime, conjugation (black arrows) occurs when a plasmid containing cell contacts a plasmid-free one. The number of transconjugant cells formed is thus equivalent to the number of Donor:Recipient encounters. The conjugation frequency thus increases linearly with increasingly available recipients. <b>B)</b> Scheme showing the conjugative transmission of a plasmid (red circle) in the same population of susceptible cells as in A), but under Frequency-Dependent Transmission (FDT). In this regime, conjugation (black arrows) is limited by the time required to complete the transfer event, thus not all Donor:Recipient contacts result in successful Transconjugant formation. The conjugation frequency is thus constant, regardless of the number of available recipients. <b>C)</b> Ideal number of transconjugants obtained per donor (y axis, T/D) as a function of the total cell concentration (x axis, N). In a Holling´s Type II functional response there is a density-dependent region where transconjugant formation increases proportionally with N (leftwards from the blue line). When N becomes saturating the formation of transconjugants does not scale any further with cell density and becomes frequency-limited (rightwards from the blue line). <b>D, E, F)</b> Transconjugants per donor ([T]/[D], y axis) obtained at different cell densities ([N], x axis) in conjugations using E. coli BW27783, on solid LB-agar surfaces matings and 1 h. conjugation time. Each graph corresponds to plasmids R388 (D), pKM101 (E) and RP4 (F). The black line represents the ideal DDT dynamics, while the red line represents the FDT.