Discovery of bioactive secondary metabolites produced by microbial strains from isolated environments and study of the biosynthesis of alpha-aminopyrones produced by Aspergillus sp. DLM38

Abstract

Microorganisms obtained from isolated environments may present a highly differentiated metabolic potential, producing in bio culture bioactive substances of interest from the medical point of view, as well as of interest for the investigation of their biosynthesis routes. This project aims to investigate the metabolism of microorganisms from endophytic and Antarctic environments, aiming the discovery of bioactive natural products. Using HPLC-ELSD-UV-MS for the dereplication of microorganisms culture medium extracts, it is proposed to isolate and identify bioactive secondary metabolites produced by endophytic actinobacteria strains isolated from plants of the island of Alcatrazes, as well as fungi from the Antarctic continent. In addition, we intend to investigate the biosynthesis of ±-aminopyrones, a class of bioactive compounds quite unusual which biosynthesis is still unknown, produced only by fungi of the genus Aspergillus. The skeletal ±-aminopyrones indicate these are of mixed biosynthetic origin, PKS-NRPS. The genome of Aspergillus sp. DLM38 was sequenced and analyzed by bioinformatics prioritizing the 5 gene clusters, which can be responsible for the biosynthesis of ±-aminopyrones. This project also proposes using Genetic Engineering tools for the inactivation of these key genes to verify if the production of ±-aminopyrones is discontinued in their absence. Mutants will be constructed by homologous recombination and evaluated by diagnostic PCR. The chemical profile produced in the culture medium by the wild-type strain and mutants will be compared by HPLC-UV-MS and UPLC-HRMS/MS with previously isolated standards, isoprofen and naphthoquinoneimine. If successful, this project will deepen the knowledge in the enzymatic machinery necessary for the production of this class of metabolites. (AU)