Induction of diverse secondary metabolites in Aspergillus fumigatus by microbial co-culture

An established culture of Aspergillus fumigatus MBC-F1-10 proved to be very receptive to external stimuli
and reacted with the production of secondary metabolites which were undetectable when the fungus was
grown under standard conditions. Firstly, co-cultivation with the type strain of Streptomyces bullii, an
isolate from hyper-arid Atacama desert soil, led to the isolation of ergosterol 1, seven metabolites
belonging to the diketopiperazine alkaloids; brevianamide F 2, spirotryprostatin A 3, 6-methoxy
spirotryprostatin B 4, fumitremorgin C and its 12,13-dihydroxy derivative (5–6), fumitremorgin B 7, and
verruculogen 8, in addition to 11-O-methylpseurotin A 9 and its new isomer 11-O-methylpseurotin A2 10.
In an independent experiment, addition of N-butyryl-DL-homoserine lactone to the culture medium led to
the production of emestrins A and B (11–12). Neither microbe produced these compounds when cultured
alone. The structures of all compounds were elucidated using NMR spectroscopic techniques and mass
spectrometric analysis. The isolated compounds were tested for their potential antibacterial and
antiprotozoal activities.