Translating metabolic exchange with imaging mass spectrometry.

Metabolic exchange between an organism and the environment, including interactions with neighboring organisms, is important for processes of organismal development. Here we develop and use thin-layer agar natural product MALDI-TOF imaging mass spectrometry of intact bacterial colonies grown on top of the MALDI target plate to study an interaction between two species of bacteria and provide direct evidence that Bacillus subtilis silences the defensive arsenal of Streptomyces coelicolor.