| Abstract |
The freshwater cyanobacterium Microcystis aeruginosa NIES‐88, which can produce microcystins, micropeptins, and argicyclamides, was subjected to a one strain many compounds (OSMAC) analysis. We report its response to two environmental stressors, temperature and iron limitation, by means of untargeted and targeted metabolomics. The results demonstrated a slower specific growth rate of 0.20 per day and 0.16 per day in adverse conditions of 37°C and iron limitation, respectively. The metabolic signature of M. aeruginosa was highly dependent on incubation temperatures. Production of microcystins LR and RR was severely downregulated while that of argicyclamide B was significantly upregulated, with a highest 10‐fold increase on day 14 of heat shock treatment. M. aeruginosa NIES‐88 was found to produce a new compound, argicyclamide D (1), in iron limited medium, which has the same macrocyclic structure as the previously reported analogs. Hence, it is proposed that acclimation of M. aeruginosa to environmental stressors might be mediated by a change in the metabolic pathways as well as modulation of the levels of their expressed metabolites.
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