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Abstracts - Gabriela T. de Paula

Streptomyces chartreusis ICBG323 ASSOCIATED WITH WINGED MALES OF Mycocepurus goeldii ANTS INHIBITS THE SPECIFIC CULTIVAR PATHOGEN

Gabriela T. de Paula1*, Ana Lígia L. de Oliveira1,2, Weilan G. P. Melo1, and Mônica T. Pupo1

1 Faculdade de Ciências Farmacêuticas de Ribeirão Preto, USP, Brazil;

2 Present address: Faculdade de Ciências Farmacêuticas - Universidade Federal do Amazonas (FCF-UFAM); Brazil

* Correspondence: mtpupo@fcfrp.usp.br

The Attini ants stand out as an interesting example of symbiotic interaction with microorganisms.1 The parasite fungi of the genus Escovopsis can compromise the viability of ant nests, thus these ants associated with actinobacteria that are able to biosynthesize antimicrobials against the Escovopsis sp.2 Bioactive metabolites produced by microbiota associated with Mycocepurus goeldii ants, mainly related to the winged males, are rare in the literature. As part of an ongoing International Cooperative Biodiversity Group (ICBG) project between Brazil and the US,3 the main objective of this project is the chemical-ecological study of the actinobacteria encoded ICBG323, isolated from Mycocepurus goeldii ants. The strain ICBG323 was isolated from M. goeldii winged males collected before the nuptial flight and it was identified as Streptomyces chartreusis by sequencing the 16S rRNA gene. Streptomyces chartreusis ICBG323 was screened against Escovopsis fungi (EM150618-2, WM151001-4, AB150620-3 and CC150618-2) in Petri dish antagonism assays and showed good inhibition, as can be seen in the figure below. However, the ethyl acetate extract and the SPE fractions of these actinobacteria have not displayed satisfactory inhibitory activities. The Petri dish bioassay to verify the possible antifungal activity mediated by VOCs (volatile organic compounds) indicated these compounds are not involved in the antagonistic activity. Therefore, the compounds involved in the antifungal activity exhibited by the actinobacterium are neither VOCs nor extracted by EtOAc. Currently, other extraction methods are being tested and the metabolism of S. chartreusis ICBG323 in single culture is being studied.

Refs.

1. Currie, C.R. et al., Nature 398, 701-704, 1999.

2. Currie, C.R. et al., Proc. Natl. Acad. Sci. -USA 96, 7998-8002, 1999.

3. Pupo et. al., J. Braz. Chem. Soc. 28, 393-401, 2017.