The genes for DNA uptake and recombination in Bacilli are commonly regulated by the transcriptional factor ComK. We have identified a ComK homologue in Bacillus coagulans, an industrial relevant organism that is recalcitrant for transformation. Introduction of B. coagulans comK gene under its own promoter region into Bacillus subtilis comK strain results in low transcriptional induction of the ...

The obligate human pathogen Neisseria gonorrhoeae is the sole aetiologic agent of the sexually transmitted infection, gonorrhea. Required for gonococcal infection, Type IV pili (Tfp) mediate many functions including adherence, twitching motility, defense against neutrophil killing, and natural transformation. Critical for immune escape, the gonococcal Tfp undergoes antigenic variation, a recomb...

To study whether the capability of horizontal DNA transfer is associated with metronidazole resistance in Helicobacter pylori, a total of 81 clinical isolates were tested for MICs of metronidazole (MTZ). The MIC assays were performed by using the E-test and reconfirmed by the agar dilution method. Natural competence assays were performed by transferring a chloramphenicol acetyltransferase casse...

Competence for genetic transformation in Streptococcus pneumoniae has previously been described as a quorum-sensing trait regulated by a secreted peptide pheromone. Recently we demonstrated that competence is also activated by reduction in the accuracy of protein biosynthesis. We have now investigated whether errors upstream of translation in the form of random genomic mutations can provide a s...

Plant surfaces, colonized by numerous and diverse bacterial species, are often considered hot spots for horizontal gene transfer (HGT) between plants and bacteria. Plant DNA released during the degradation of plant tissues can persist and remain biologically active for significant periods of time, suggesting that soil or plant-associated bacteria could be in direct contact with plant DNA. In ad...

DNA processing chain A (DprA) is a DNA-binding protein that is ubiquitous in bacteria and expressed in some archaea. DprA is active in many bacterial species that are competent for transformation of DNA, but its role in Neisseriameningitidis (Nm) is not well characterized. An Nm mutant lacking DprA was constructed, and the phenotypes of the wild-type and ΔdprA mutant were compared. The salient ...

ClpC of Bacillus subtilis, controlling competence gene expression and survival under stress conditions, is encoded by the fourth gene of a six-gene operon. The product of orf1 contains a potential helix-turn-helix motif, but shows no significant similarities with known protein sequences. The second and third genes encode proteins with similarities to zinc-finger proteins (orf2) and arginine kin...

We have found that two DNA repair/recombination proteins localize differentially to the cell poles in competent Bacillus subtilis cells. RecA protein colocalized with competence protein ComGA, and its polar localization largely depended on ComGA and ComK activity, while RecN oscillated between the poles in a minute time frame, independent of any competence factor. Oscillation of RecN arrested u...

Perry, Dennis (Northwestern University Medical School, Chicago, Ill.) and Hutton D. Slade. Optimal conditions for the transformation of streptococci. J. Bacteriol. 85:636-642. 1963.-A study of the properties of the streptococcal transforming system, employing streptomycin resistance as a marker, resulted in a 1,000- to 10,000-fold increase in the rate of transformation. In some cases, as high a...

Although Escherichia coli does not have a natural transformation process, strains of E. coli can incorporate extracellular plasmids into cytoplasm 'naturally' at low frequencies. A standard method was developed in which stationary phase cells were concentrated, mixed with plasmids, and then plated on agar plates with nutrients which allowed cells to grow. Transformed cells could then be selecte...