Application of Biolog FF MicroPlate for substrate utilization and metabolite profiling of closely related fungi.

Filamentous fungi are known to have unique biochemical pathways to assimilate a vast array of simple and complex nutrients available to them and to produce a variety of metabolites. Morphological and biochemical uniqueness of these organisms are commonly used for their identification, but differentiation of closely related cultures requires extensive phenotypic and genomic investigations. The Biolog FF MicroPlate was recently introduced for rapid identification of common filamentous fungi based on their abilities to utilize 95 discrete substrates. We used the FF MicroPlate for substrate utilization, growth, secondary metabolite and antimicrobial profiles of some fungal cultures important to our microbial drug discovery program. Culture growth was monitored by change in absorbance in each well, and the presence of secondary metabolites and their corresponding bioactivities was detected by LCMS analyses and antimicrobial assays of the extracts of each well, respectively. Fingerprints were created with Spotfire visualization software, and data were analyzed in various ways. The substrate utilization fingerprints were useful in selecting media components for media optimization of secondary metabolite production for the various cultures. In general, a strong correlation was found among substrate utilization, growth, antimicrobial activity and presence of the responsible secondary metabolites. The method was used for dereplication of isolated fungi and in the differentiation of closely related variants within one species.