Heat treatment did not fully inhibit QQ
activity in all isolates, indicating the production of (a) heat-stable QQ
molecule(s)
Some isolates lose QQ capacity after proteinase K
treatment, while others remain able to quench QS. Therefore, it
seems plausible that some isolates produce and secrete heat-stable,
low molecular weight inhibitory compounds. The results of the SEC
experiments further support this hypothesis. Future research will
have to reveal the chemical structure of these active molecules as well
as their mechanism of action.