Natural Genetic Transformation: A Direct Route to Easy Insertion of Chimeric Genes into the Pneumococcal Chromosome

Author(s):  
Isabelle Mortier-Barrière ◽  
Nathalie Campo ◽  
Mathieu A. Bergé ◽  
Marc Prudhomme ◽  
Patrice Polard
1990 ◽  
Vol 154 (4) ◽  
pp. 380-385 ◽  
Author(s):  
Michael G. Lorenz ◽  
Wilfried Wackernagel

PLoS Genetics ◽  
2013 ◽  
Vol 9 (9) ◽  
pp. e1003819 ◽  
Author(s):  
Calum Johnston ◽  
Stéphanie Caymaris ◽  
Aldert Zomer ◽  
Hester J. Bootsma ◽  
Marc Prudhomme ◽  
...  

2003 ◽  
Vol 69 (3) ◽  
pp. 1721-1727 ◽  
Author(s):  
Larissa Hendrickx ◽  
Martina Hausner ◽  
Stefan Wuertz

ABSTRACT Horizontal gene transfer by natural genetic transformation in Acinetobacter sp. strain BD413 was investigated by using gfp carried by the autonomously replicating plasmid pGAR1 in a model monoculture biofilm. Biofilm age, DNA concentration, and biofilm mode of growth were evaluated to determine their effects on natural genetic transformation. The highest transfer frequencies were obtained in young and actively growing biofilms when high DNA concentrations were used and when the biofilm developed during continuous exposure to fresh medium without the presence of a significant amount of cells in the suspended fraction. Biofilms were highly amenable to natural transformation. They did not need to advance to an optimal growth phase which ensured the presence of optimally competent biofilm cells. An exposure time of only 15 min was adequate for transformation, and the addition of minute amounts of DNA (2.4 fg of pGAR1 per h) was enough to obtain detectable transfer frequencies. The transformability of biofilms lacking competent cells due to growth in the presence of cells in the bulk phase could be reestablished by starving the noncompetent biofilm prior to DNA exposure. Overall, the evidence suggests that biofilms offer no barrier against effective natural genetic transformation of Acinetobacter sp. strain BD413.


2001 ◽  
Vol 12 (3) ◽  
pp. 217-243 ◽  
Author(s):  
D.G. Cvitkovitch

The oral streptococci are normally non-pathogenic residents of the human microflora. There is substantial evidence that these bacteria can, however, act as "genetic reservoirs" and transfer genetic information to transient bacteria as they make their way through the mouth, the principal entry point for a wide variety of bacteria. Examples that are of particular concern include the transfer of antibiotic resistance from oral streptococci to Streptococcus pneumoniae. The mechanisms that are used by oral streptococci to exchange genetic information are not well-understood, although several species are known to enter a physiological state of genetic competence. This state permits them to become capable of natural genetic transformation, facilitating the acquisition of foreign DNA from the external environment. The oral streptococci share many similarities with two closely related Gram-positive bacteria. S. pneumoniae and Bacillus subtilis. In these bacteria, the mechanisms of quorum-sensing, the development of competence, and DNA uptake and integration are well-charaterized. Using this knowledge and the data available in genome databases allowed us to identify putative genes involved in these processes in the oral organism Streptococcus mutans. Models of competence development and genetic transformation in the oral streptococci and strategies to confirm these models are discussed. Future studies of competence in oral biofilms, the natural environment of oral streptococci, will be discussed.


2007 ◽  
Vol 158 (10) ◽  
pp. 767-778 ◽  
Author(s):  
Ola Johnsborg ◽  
Vegard Eldholm ◽  
Leiv Sigve Håvarstein

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Matthieu J. Bergé ◽  
Chryslène Mercy ◽  
Isabelle Mortier-Barrière ◽  
Michael S. VanNieuwenhze ◽  
Yves V. Brun ◽  
...  

1999 ◽  
Vol 179 (2) ◽  
pp. 485-490 ◽  
Author(s):  
Derry K Mercer ◽  
Claire M Melville ◽  
Karen P Scott ◽  
Harry J Flint

2006 ◽  
Vol 188 (14) ◽  
pp. 5177-5186 ◽  
Author(s):  
Bhushan V. Desai ◽  
Donald A. Morrison

ABSTRACT Natural genetic transformation in Streptococcus pneumoniae entails transcriptional activation of at least two sets of genes. One set of genes, activated by the competence-specific response regulator ComE, is involved in initiating competence, whereas a second set is activated by the competence-specific alternative sigma factor ComX and functions in DNA uptake and recombination. Here we report an initial characterization of CoiA, a ComX-dependent gene product that is induced during competence and is required for transformation. CoiA is widely conserved among gram-positive bacteria, and in streptococci, the entire coiA locus composed of four genes is conserved. By use of immunoblot assay, we show that, similar to its message, CoiA protein is transient, appearing at 10 min and largely disappearing by 30 min post-competence induction. Using complementation analysis, we establish that coiA is the only gene of this induced locus needed for transformability. We find no indication of CoiA having a role in regulating competence. Finally, using 32P- and 3H-labeled donor DNA, we demonstrate that a coiA mutant can internalize normal amounts of donor DNA compared to the wild-type strain but is unable to process it into viable transformants, suggesting a role for CoiA after DNA uptake, either in DNA processing or recombination.


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