Natural Escherichia coli strains undergo cell-to-cell plasmid transformation.
Horizontal gene transfer is a strong tool that allows bacteria to adapt to various environments. Although three conventional mechanisms of horizontal gene transfer (transformation, transduction, and conjugation) are well known, new variations of these mechanisms have also been observed. We recently reported that DNase-sensitive cell-to-cell transfer of nonconjugative plasmids occurs between laboratory strains of Escherichia coli in co-culture. We termed this phenomenon "cell-to-cell transformation." In this report, we found that several combinations of Escherichia coli collection of reference (ECOR) strains, which were co-cultured in liquid media, resulted in DNase-sensitive cell-to-cell transfer of antibiotic resistance genes. Plasmid isolation of these new transformants demonstrated cell-to-cell plasmid transfer between the ECOR strains. Natural transformation experiments, using a combination of purified plasmid DNA and the same ECOR strains, revealed that cell-to-cell transformation occurs much more frequently than natural transformation under the same culture conditions. Thus, cell-to-cell transformation is both unique and effective. In conclusion, this study is the first to demonstrate cell-to-cell plasmid transformation in natural E. coli strains.
Graduate School of Humanities and Sciences, Nara Women's University, 630-8506 Kitauoya-nishimachi, Nara, Japan.
Akiko
A
Matsumoto
Graduate School of Humanities and Sciences, Nara Women's University, 630-8506 Kitauoya-nishimachi, Nara, Japan.
Ayuka
A
Sekoguchi
Faculty of Human Life and Environment, Nara Women's University, 630-8506 Kitauoya-nishimachi, Nara, Japan.
Junko
J
Imai
Graduate School of Humanities and Sciences, Nara Women's University, 630-8506 Kitauoya-nishimachi, Nara, Japan.
Kumiko
K
Kondo
Graduate School of Humanities and Sciences, Nara Women's University, 630-8506 Kitauoya-nishimachi, Nara, Japan.
Yuka
Y
Shibata
Graduate School of Humanities and Sciences, Nara Women's University, 630-8506 Kitauoya-nishimachi, Nara, Japan; Faculty of Human Life and Environment, Nara Women's University, 630-8506 Kitauoya-nishimachi, Nara, Japan. Electronic address: smaeda@cc.nara-wu.ac.jp.
Sumio
S
Maeda
D002450:Cell Communication / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000145:classification / Q000166:cytology* / Q000235:genetics*; D022761:Gene Transfer, Horizontal / Q000235:genetics*; D010957:Plasmids / Q000235:genetics*; D013045:Species Specificity; D014169:Transformation, Bacterial / Q000235:genetics*
D004269:DNA, Bacterial
E. coli; ECOR; Horizontal gene transfer; Transformation