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Lookup NU author(s): Dr Leendert Hamoen
Natural isolates of Bacillus subtilis are often difficult to transform due to their low genetic competence levels. Here we describe two methods that stimulate natural transformation. The first method uses plasmid pGSP12, which expresses the competence transcription factor ComK and stimulates competence development about 100-fold. The second method stimulates Campbell-type recombination of DNA ligation mixtures in B. subtilis by the addition of polyethylene glycol. We employed these novel methods to study the regulation of the synthetases for the lipopeptide antibiotics mycosubtilin (myc) and surfactin (srfA) in B. subtilis strain ATCC 6633. By means of lacZ reporter fusions, it was shown that the expression of srfA is >100 times lower in strain ATCC 6633 than in the laboratory strain B. subtilis 168. Expression of the myc operon was highest in rich medium, whereas srfA expression reached maximal levels in minimal medium. Further genetic analyses showed that the srfA operon is mainly regulated by the response regulator ComA, while the myc operon is primarily regulated by the transition-state regulator AbrB. Although there is in vitro evidence for a synergistic activity of mycosubtilin and surfactin, the expression of both lipopeptide antibiotics is clearly not coordinated. Copyright © 2007, American Society for Microbiology. All Rights Reserved.
Author(s): Duitman EH, Wyczawski D, Boven LG, Venema G, Kuipers OP, Hamoen LW
Publication type: Article
Publication status: Published
Journal: Applied and Environmental Microbiology
Year: 2007
Volume: 73
Issue: 11
Pages: 3490-3496
Print publication date: 01/06/2007
Date deposited: 18/06/2010
ISSN (print): 0099-2240
ISSN (electronic): 1098-5336
Publisher: American Society for Microbiology
URL: http://dx.doi.org/10.1128/AEM.02751-06
DOI: 10.1128/AEM.02751-06
PubMed id: 17416694
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