We grew three independent biological replicates of a wild type (630Derm) or Clostron-generated spo0A mutant (CT::spo0A -a kind gift of the Minton lab) in glucose-free TTY medium. We harvested culture supernatant at late-exponential phase (approximately 7 hours post inoculation), the transition phase between exponential and stationary growth phase (approximately 9 hours post inoculation), as well as two time points in stationary phase (24 and 48 hours post inoculation) and determined the toxin endpoint titres (see Materials and Methods). In contrast to previous findings, we observed a small (#4-fold) increase in the toxicity of supernatants derived from spo0A mutant cells compared to wild type, but in all cases this difference was not statistically significant (p.0.05, independent sample t-test). In other medium (BHIS), we observed no differences at all (data not shown).