Chemical Screening and Antibacterial Testing of Fungal Endophytes

Endophytes are bacteria or fungi that live within a host plant. The plant host provides a home for endophytes, and in return endophytes produce primary and secondary metabolites, of which many of the secondary metabolites possess biological activities. When microorganisms are grown under various media conditions, they produce different natural products as gene regulation is affected by environmental clues. Biologically active natural products are of huge biomedical interest as they can improve human health: over 50% of FDA approved clinically used drugs are natural products or natural products derived.\ud \ud We have been working with endophytic fungi isolated from marine algae. We tested their metabolic expression of natural products under various culture conditions and tested their extracts against common human pathogens like Bacillius subtilis, P. aeruginosa, Candida albicans and Staphlacoccus aureus. This chemical screening allows us to select strains for further purification of the secondary fungal metabolites as drug leads.\ud The use of High-Performance Liquid Chromatography (HPLC), Liquid Chromatography-Mass Spectrometry (LCMS) and Nuclear Magnetic Resonance (NMR) allows us to first purify a compound, determine its molecular weight and then elucidate its chemical structure