Roberto G. S. Berlinck

rgsberlinck@iqsc.usp.br

Instituto de Química de São Carlos, Universidade de São Paulo, CP 780, CEP 13560-970, São Carlos, SP, Brazil

Living organisms present defense traits against predators and pathogenic agents. The production and/or accumulation of defensive chemical substances derived from secondary metabolism represents one of the most successful forms of adaptation in virtually all organisms that do have an immune system. Increasing evidences show that microorganisms are often the actual source of many of these substances. Recent studies clearly indicate that secondary metabolites originally isolated from marine invertebrates are, in fact, produced by associated microorganisms, whether symbionts or those in mutualistic relationships.

Although research aimed at establishing the true origin of secondary metabolites accumulated by marine invertebrates had considerably advanced, much less progress has been made in understanding the true microbial diversity associated with marine invertebrates and vertebrates. The investigation of microorganisms associated with non-filter-feeding marine organisms has been far less explored, possibly due to the assumption that many of these organisms lack chemical defenses. However, this is a questionable premise, since microorganisms associated with non-filtering macro-organisms can significantly contribute to their survival success.

Marine and marine-derived fungi, bacteria, and cyanobacteria associated with diverse macro-organisms have been the most investigated groups due to their metabolic diversity expressed under cultivation conditions. Among the metabolite groups of our interest, we have investigated the biosynthetic origin of aminopyrones produced by a fungus of the genus Aspergillus, and terpenes produced by the Biatriospora sp. CBMAI 1333 sp. strain, non-ribosomal peptides produced by a bacterium of the genus Pseudovibrio, and alkaloids produced by a Penicillium sp. strain. More recently, a series of polyketides produced by a Peroneutypa fungal strain were isolated, whose biosynthesis appears to involve a cyclization through a [4+2] cycloaddition reaction, in addition to the production of additional polyketides with singular chemical structures. These investigations demonstrate the chemical diversity of microorganisms originating from the marine environment, with unique biosynthetic pathways.

Keywords: marine microbes, marine organisms, biosynthesis, polyketides, alkaloids, NRPS

Acknowledgements: to FAPESP, CAPES and CNPq for the financial support.

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