Induced production of cytochalasans in co-culture of marine fungus Aspergillus flavipes and actinomycete Streptomyces sp.

Secondary metabolites profiles of co-culture of Aspergillus flavipes and Streptomyces sp. that isolated from the same habitat showed an induced production of a series of cytochalasans (five aspochalasins and rosellichalasin, determined by MS and NMR analysis). These cytochalasans were found to be produced by A. flavipes in LC–MS comparison analysis, and biological activity assays revealed that they were able to cause cytotoxic effects against Streptomyces sp. within a wide range of concentrations without causing any effect to the producer A. flavipes, which favoured the producer in competition. Further induction mechanism study applying membrane-separated culture and morphology study with scanning electron microscopy (SEM) suggested that the successful induction of active secondary metabolites required microbial physical contact.