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FRIMEDBIO-Fri prosj.st. med.,helse,biol


Tildelt: kr 6,3 mill.

In this proposal we set out to test alternative hypotheses for the evolution and maintenance of natural competence for transformation, as well as cannibalism and martyrdom in bacteria. These two processes are fascinating strategies for bacterial adaptatio n and survival. An increased understanding of the selective pressures responsible for the maintenance of competence and cannibalism is not only interesting from a basic research point of view, it may also lead to new clues as how to deal with the evolutio n and spread of pathogenic and antibiotic resistant bacteria. Horizontal gene transfer (HGT) and incorporation of DNA from other organisms, enables bacteria to sample the entire prokaryotic, archeal and even eukaryotic DNA sequence space. It is clear tha t this capacity for horizontal DNA transfer has played and continues to play a prominent role in bacterial evolution by providing bacteria with a source of genetic variation required for adaptive evolution as well as genes needed for habitat- and niche- e xpansion. Not so clear is how this capacity evolved and is maintained. We recently proposed a novel hypothesis for the maintenance of competence and transformation in Bacillus subtilis. We showed theoretically and experimentally that competence induced gr owth arrest can provide a selective advantage during episodes of antibiotic selection when compared to non competent isogenic mutants. Here we set out to test the generality of these results. We also test another hypothesis for the maintenance and evoluti on of competence and transformation; the DNA repair hypotheses. We also want to study the population dynamics of bacterial cannibalism recently described in B. subtilis, and further test the possibility that it is maintained and potentially has evolved as an anti invasion strategy rather than an elaborate and potentially costly mechanism for postponing sporulation.


FRIMEDBIO-Fri prosj.st. med.,helse,biol