E. coli competence

[Tom Schneider]

In article <35urfl$juf at charm.magnus.acs.ohio-state.edu>
aottolen at magnus.acs.ohio-state.edu (Abramo C Ottolenghi) writes:

| Although the idea of cell to cell communication is interesting I do not believe
| it is relevant to the discussion relating to E. coli competence as described in
| the paper in question.  If competence is due to cell to cell communication how 
| can the drop in competence that is seen when cell densities increase from 0.94 
| to 1.0 be explained?

One would also have to explain the valley between the two peaks.  A simple
explanation is that there are two different mechanisms that operate at
different concentrations of cells or communication molecule.  Each peaks at a
different concentration (for some physiological/evolutionary reason).  One
could imagine that there was originally only one mechanism and that there was a
gene duplication and drift.  Why there are two is mysterious.

Of course one might imagine more complex explanations based on, for example,
differential equations that come out to a sine wave.

  Tom Schneider
  National Cancer Institute
  Laboratory of Mathematical Biology
  Frederick, Maryland  21702-1201
  toms at ncifcrf.gov
  http://fconvx.ncifcrf.gov:2001/~toms/info.html