DNA mediated attachment in biofilms

One questioner after my CIfAR talk asked whether competence genes might have some other function for the cell.  When I raised this at lab meeting yesterday, the post-doc pointed out that competent cells are able to attach to and pull on the DNA that's a major component of biofilms, and we considered whether this might help cells to establish biofilms, to move within biofilms, or to avoid being displaced from biofilms.

We then started considering experiments we might do.  My idea was to precoat glass surfaces with DNA, incubate them with cultures of cells that can form biofilms, and then measure whether the DNA increased the initial steps of biofilm formation.  The lab down the hall studies, among other things, biofilm formation by Campylobacter, which is naturally competent, so we might work with them to test this in both H. influenzae and Campylobacter. 

What controls would we want?  We'd certainly need to test cells that can and cannot express their competence genes.  Competent cells express type IV pili, and these might allow attachment and pulling. independent of their involvement in DNA uptake, but I think doing the experiment with and without DNaseI would control for DNA-independent effects of pili.

The basic assay for biofilm formation is very simple, and the Research Associate's extensive experience turns out to include doing lots of these.  I think it's time to talk to my colleague down the hall, to see if she's interested.