Conjugation transfers plasmids between bacteria and spreads antibiotic resistance genes. We study how the type-IV secretion system (T4SS) translocates DNA.
Conjugative plasmids encode a T4SS and a pilus. The T4SS transfers single-stranded plasmid DNA from the donor to the recipient cell. The structural changes of the T4SS during DNA translocation are unresolved.
Together with the Lesterlin group, we used live-cell microscopy and fluorescent reporters of DNA transfer. DNA transfer occurred between cells in direct contact and between physically distant cells that were connected by an extended F pilus.
Together with the Nadell group, we followed transfer of the plasmid pED208 in E. coli biofilms. Conjugative pili enabled matrix-deficient cells to form dense biofilms with increased antibiotic and phage tolerance. Plasmid-carrying cells dispersed less than plasmid-free cells.
Together with the group of Debnath Ghosal at the University of Melbourne, we develop transcriptional and translational reporters for the F-like T4SS in its DNA-transfer state. We combine these reporters with fluorescence microscopy and cryo-electron tomography to resolve the structural transitions during DNA translocation.
Contact: Mario Delgadillo-Guevara, E-mail
