Chemical and biological studies of symbiotic bacteria isolated from Atta sexdens rubropilosa

Abstract

The leaf-cutting ants provide fresh plant material for fungi that they cultivate for food in gardens inside their nests. These ants have associated with bacteria that produce antibiotics to protect their colonies against invaders. The natural products produced by these bacteria were selected by ants during thousands of years of evolution and may be useful for drug discovery. In this ongoing PhD project, we have found that the leaf-cutting ants Atta sexdens rubropilosa are associated with symbiotic bacteria of the genus Burkholderia sp. that produces unidentified antibiotics. Beyond that, Serratia marcescens 3FLB2 strains isolated from ants' bodies produce pyrazines similar with A. sexdens rubropilosa's trail pheromone. These bacteria can produce compounds involved in the chemical communication between these ants in a new kind of symbiosis. The main objectives of the sandwich doctorate at Jon Clardy's laboratory at Harvard Medical School will be: the isolation of bacterial antibiotics and the study of the biosynthetic pathways involved in the production of pyrazines in order to elucidate the biosynthesis of the trail pheromone. For this, the metabolites produced by Burkholderia sp. will be isolated, its antibiotic activities will be evaluated, and the genome of S. marcescens 3FLB2 will be sequenced. The internship at Harvard Medical School is in concordance to FAPESP PhD project. It will be important to further explore the PhD student results obtained in Brazil and to learn chemical biology methodologies. (AU)