Tales of conjugation and sex pheromones

Abstract

REVIEW REVIEW use of a technique that had recently been reported by Godson and Sinsheimer 6 that utilized a detergent mixture of Brij 58 (a neutral detergent) and deoxycholate for lysis of phageinfected E. coli. During a relatively low-speed centrifugation step, the vast majority of chromosomal DNA pelleted leaving the supernatant greatly enriched in plasmid DNA. Sucrose gradient analyses of these "cleared lysates" revealed a ColE1-protein complex sedimenting slightly faster (24S) than the 23S protein-free supercoiled DNA. Surprisingly, when the 24S complex was exposed to conditions expected to affect protein structure such as proteases, strong ionic detergents or heat, the 24S complex converted to a 17S relaxed (open circular) configuration. The relaxation event involved the introduction of a strand-specific nick in the supercoiled plasmid; we therefore called the 24S entity a "relaxation complex". 7,8 The percentage of plasmid DNA that was present in the complexed state varied from less than 30%, when glucose was in the growth medium, to more than 80% when glucose was absent.

Mobility of the Native Bacillus subtilis Conjugative Plasmid pLS20 Is Regulated by Intercellular Signaling

“…Examples of these are (i) the broad host-range plasmid pIP501, originally isolated from Streptococcus agalactiae [10], [11, and references therein], pCW3 of Clostridium perfringens [12], the Staphylococcal aureus plasmids pGO1 and pSK41 [13], [14], and the Enterococcus faecalis plasmids pAD1 and pCF10. For the latter plasmids their transcriptional regulation has also been studied (for review see, [15]–[17]). A characteristic feature of these latter plasmids is that conjugation is induced by pheromones that are produced by plasmid-free recipient cells.…”

Pheromone peptide cOB1 from native Enterococcus faecalis forms amyloid‐like structures: A new paradigm for peptide pheromones

“…In the case of E. faecalis , the peptide sex pheromones are evolved as part of the pheromone‐based conjugation system . The donor cell in the conjugation system specifically recognizes a unique pheromone and induces the conjugative mating response by producing aggregation substance that helps in effective mating pair formation and subsequent plasmid transfer . In most of the cases, the subsequent mobile element transfer is mainly responsible for the generation of virulent and drug‐resistant strains.…”

pGIAK1, a Heavy Metal Resistant Plasmid from an Obligate Alkaliphilic and Halotolerant Bacterium Isolated from the Antarctic Concordia Station Confined Environment

“…Gene pGIAK1_7 encode a putative lipoprotein. In the case of pheromone-inducible conjugative plasmid pAD1 of E. faecalis , the pheromone sequences appeared within the carboxyl termini of signal sequences of lipoprotein precursors [71]. Moreover, pGIAK1_8 encodes a putative membrane protein and pGIAK1_9 encodes a potential cell wall hydrolase protein.…”