Conjugation plasmid transfer

The first example of chemical communication in low-GC Gram-positive bacteria was discovered in 1978 by Dunny, Clewell and their colleagues.93 It was found that conjugative plasmid transfer of Enterococcus faecalis was induced by a chemical substance, termed sex pheromone, which is secreted from plasmid-free recipient cells. Several years later, the structure of the sex pheromone was elucidated to be an oligopeptide by Suzuki et al Since this discovery, a variety of cell-to-cell communication events in Gram-positive bacteria have been found to be mediated by peptidic substances.95-97... 

Figure 8 Structures of nonmodified oligopeptide signal molecules mediating intraspecies cell-to-cell communication in Gram-positive bacteria, (a) Peptide sex pheromones and their inhibitors involved in the regulation of conjugative plasmid transfer in Enterococcus faecalis. (b) Competence- and sporulation-stimulating factors of Bacillus subtilis.

Figure 9 Sex pheromone signaling leading to conjugative plasmid transfer in Enterococcus faecalis. Sex pheromone (cX) is encoded in the N-terminal leader moiety of lipoprotein. The leader peptide is cleaved off after the translocation of lipoprotein and further processed to generate the pheromone, which is eventually excreted. The secreted pheromone is reimported into the plasmid-donor cell and bound to TraA, which is a transcriptional regulator. Eventually, aggregation substance is induced on the donor cell surface, which leads to plasmid transfer to recipient cell.

High-frequency conjugal plasmid transfer from gram-negative Escherichia coli to various gram-positive coryneform bacteria. J. Bacteriol, 172 (3), 1663-1666. 

Williams DR, Young DI, Young M (1990) Conjugative plasmid transfer from Escherichia coli to Clostridium acetobutylicum. J Gen Microbiol 136 819-826... 

Argyle JL, Rapp-Giles BJ, Wall JD. 1992. Plasmid transfer by conjugation in Desulfovibrio desulfuricans. FEMS Microbiol Lett 94 255-62. 

Piper, K.R., Beck vonBodman, S., FarrandS.K. Conjugation factor of Agrobacterium tumefaciens regulates Ti plasmid transfer by autoinduction. Nature 1993 362 448-450. 

S. aureus transposons are small mobile elements that often encode resistance genes (P-lactamase, resistance to erythromycin and tetracycline). All the transposons encode a transposase gene, and the product of this gene catalyses excision and/or replication of the element, as well as integration. Horizontal transfer of transposons to other S. aureus cells is presumably mediated by another MGE that is transferred, most likely a plasmid transferred by transduction or conjugation. Conjugative transposons have also been described in S. aureus. However, it is not clear if native conjugative transposons are found in S. aureus (Novick 1990). 

The expression vehicle, pRKENMut, was first transformed into E.coli SI7-1, which carries the genes necessary for plasmid transfer via conjugation in its genome, and was then mated into ALMl and PUFALMX21 essentially as described in ref. 18. 

A B1 host-vector system consists of a host with low viability in natural conditions. The vector must be dependent on the host and incapable of transfer to other cells. Examples of B1 host-vector systems are EKl (based on the bacterium Escherichia coli K12 and a plasmid which cannot conjugate or transfer to other bacteria), SCI (a laboratory-maintained strain of the yeast Saccharomyces cerevisiae as host and a plasmid or minichromosome as vector) and BSl (the bacterium Bacillus subtilis Marburg 168 as host and a plasmid). B2 host-vector systems consist of a host with especially low viability in natural conditions and a vector which depends on the host completely. The most common example is EK2 (a defective strain of E. coli K12 and the well-characterised plasmid pBR322). 

An F factor gene involved in conjugal DNA transfer. The mutation severely reduces the self-transmissibility of the F factor and plasmid DNA as well... 

Genetic material can be transferred horizontally between bacterial cells either as free DNA by transformation or as plasmid DNA via conjugational... 

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