Bioactive Metabolites from the Deep Subseafloor Fungus Oidiodendron griseum UBOCC-A-114129.

Marion Navarri,Georges Barbier,Yannick Fleury,Blandine Baratte,Arnaud Bondon,Sandrine Pottier,Camille Jégou,Gaëtan Burgaud,Sandrine Ruchaud,Stéphane Bach

doi:10.3390/md15040111

Abstract

Four bioactive compounds have been isolated from the fungus Oidiodendron griseum UBOCC-A-114129 cultivated from deep subsurface sediment. They were structurally characterized using a combination of LC–MS/MS and NMR analyses as fuscin and its derivatives (dihydrofuscin, dihydrosecofuscin, and secofuscin) and identified as polyketides. Albeit those compounds were already obtained from terrestrial fungi, this is the first report of their production by an Oidiodendron species and by the deepest subseafloor isolate ever studied for biological activities. We report a weak antibacterial activity of dihydrosecofuscin and secofuscin mainly directed against Gram-positive bacteria (Minimum Inhibitory Concentration (MIC) equal to Minimum Bactericidal Concentration (MBC), in the range of 100 μg/mL). The activity on various protein kinases was also analyzed and revealed a significant inhibition of CDC2-like kinase-1 (CLK1) by dihysecofuscin.

Highlights

The ocean harbors a tremendous diversity of habitats, ranging from coastal waters to the deep biosphere, where microorganisms, through their biotic and abiotic interactions, are the major actors of the biogeochemical processes [1,2]
We investigated investigated the antimicrobial activity of secofuscin secofuscin and dihydrosecofuscin since these since these
We characterized four bioactive compounds produced by O. griseum, isolated from a sample collected at 765 m below the sea floor

Summary

Introduction

The ocean harbors a tremendous diversity of habitats, ranging from coastal waters to the deep biosphere, where microorganisms, through their biotic and abiotic interactions, are the major actors of the biogeochemical processes [1,2]. Recent studies strongly support the idea that marine microbial communities host fungi as an important component in different kinds of habitats, including the deep biosphere [3]. Deep subseafloor sediment microbial communities are in constant interactions though the production of a wide array of secondary metabolites, as recently revealed using metatranscriptomics [4,5]. Given that a large number of marine microorganisms can produce a wide array of bioactive metabolites and has received a great amount of attention in the search for natural compounds [6,7,8], the deep biosphere appears to remain an untapped reservoir. An exhaustive culture-based approach allowed us to isolate 183 deep subsurface marine fungi [3]. An antimicrobial screening on 110 of those fungal isolates highlighted that 33% of the

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Discussion

Conclusion