Antibiotics

Biography

Biography: Karol Rodríguez-Peña

Abstract

Endophytes are microorganisms that inhabit plants without causing apparent damage. It has been found that the interaction between the host plant and endophyte is based on both physical and chemical mechanisms. The secondary metabolism of these microorganisms which allows them to defend themselves or communicate with their host, as well as their unique habitat make them a very interesting source of new molecules with biological activity. Actinomycetes are a group of Grampositive bacteria that have been extensively studied for their ability to produce a variety of secondary metabolites, especially the genus Streptomyces. However, it has recently been found by genome mining studies among some others, that other genera of actinomycetes that have hardly been studied are also capable of producing a large number of compounds. In this study, endophyte isolation was made from the medicinal plant Amphipterygium adstringens. Four actinomycetes were isolated: one of the genus Streptomyces and three others closest to the genus Actinoplanes. Phylogenetic studies place the latter three strains as potential new species. Sequential extracts were conducted, first with dichloromethane (DCM) and then with ethyl acetate (EtAc). The minimum inhibitory concentration was determined with Gram-positive, Gram-negative and a yeast. Extracts from the strain NF3 showed significant activity against the Gram-positive bacteria tested at 0.1μg/mL with DCM and 6.3 μg/ mL with EtAc, making it a very attractive strain for further elucidation of bioactive molecules. The extracts from strain TFC3 meanwhile, showed activity against Bacillus subtilis with 200 μg/mL in both DCM and EtAc. These same extracts were tested against cancer cell lines MCF7 and HeLa, as well as with with HaCaT as a healthy cell line. The extract from the NF3 strain produced mortality higher than 80% with 0.4 μg/mL in MCF7, 0.8 μg /mL for HeLa and 1.6 μg/mL for HaCaT. The putative Actinoplanes extracts had moderate activity only at 200 μg/mL with different cell lines. However, genomic studies of closely related strains indicate that these strains have enormous potential due to the large number of clusters that encode various cryptic secondary metabolite pathways.