title: Deep Subseafloor Fungi as an Untapped Reservoir of Amphipathic Antimicrobial Compounds.
abstract: The evolving global threat of antimicrobial resistance requires a deep renewal of the antibiotic arsenal including the isolation and characterization of new drugs. Underexplored marine ecosystems may represent an untapped reservoir of novel bioactive molecules. Deep-sea fungi isolated from a record-depth sediment core of almost 2000 m below the seafloor were investigated for antimicrobial activities. This antimicrobial screening, using 16 microbial targets, revealed 33% of filamentous fungi synthesizing bioactive compounds with activities against pathogenic bacteria and fungi. Interestingly, occurrence of antimicrobial producing isolates was well correlated with the complexity of the habitat (in term of microbial richness), as higher antimicrobial activities were obtained at specific layers of the sediment core. It clearly highlights complex deep-sea habitats as chemical battlefields where synthesis of numerous bioactive compounds appears critical for microbial competition. The six most promising deep subseafloor fungal isolates were selected for the production and extraction of bioactive compounds. Depending on the fungal isolates, antimicrobial compounds were only biosynthesized in semi-liquid or solid-state conditions as no antimicrobial activities were ever detected using liquid fermentation. An exception was made for one fungal isolate, and the extraction procedure designed to extract amphipathic compounds was successful and highlighted the amphiphilic profile of the bioactive metabolites.
authors.affiliation: Laboratoire de Biodiversité et d'Ecologie Microbienne (EA 3882), Université de Brest, Technopole Brest Iroise, 29280 Plouzané, France. marion.navarri@univ-brest.fr.
authors.forename: Marion
authors.initials: M
authors.lastname: Navarri
authors.affiliation: Laboratoire de Biodiversité et d'Ecologie Microbienne (EA 3882), Université de Brest, Technopole Brest Iroise, 29280 Plouzané, France. camille.jegou@univ-brest.fr.
authors.forename: Camille
authors.initials: C
authors.lastname: Jégou
authors.affiliation: Laboratoire de Biodiversité et d'Ecologie Microbienne (EA 3882), Université de Brest, Technopole Brest Iroise, 29280 Plouzané, France. laurence.meslet@univ-brest.fr.
authors.forename: Laurence
authors.initials: L
authors.lastname: Meslet-Cladière
authors.affiliation: Laboratoire de Biodiversité et d'Ecologie Microbienne (EA 3882), Université de Brest, Technopole Brest Iroise, 29280 Plouzané, France. benjamin.brillet@univ-brest.fr.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Brillet
authors.affiliation: Laboratoire de Biodiversité et d'Ecologie Microbienne (EA 3882), Université de Brest, Technopole Brest Iroise, 29280 Plouzané, France. georges.barbier@univ-brest.fr.
authors.forename: Georges
authors.initials: G
authors.lastname: Barbier
authors.affiliation: Laboratoire de Biodiversité et d'Ecologie Microbienne (EA 3882), Université de Brest, Technopole Brest Iroise, 29280 Plouzané, France. gaetan.burgaud@univ-brest.fr.
authors.forename: Gaëtan
authors.initials: G
authors.lastname: Burgaud
authors.affiliation: Laboratoire de Biodiversité et d'Ecologie Microbienne (EA 3882), Université de Brest, Technopole Brest Iroise, 29280 Plouzané, France. yannick.fleury@univ-brest.fr.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Fleury
mesh_terms: D000900:Anti-Bacterial Agents / Q000302:isolation & purification* / Q000494:pharmacology; D000935:Antifungal Agents / Q000302:isolation & purification* / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D005658:Fungi / Q000187:drug effects / Q000302:isolation & purification* / Q000378:metabolism; D019015:Geologic Sediments / Q000382:microbiology*; D012623:Seawater / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents
keywords: amphipathic compounds; antimicrobial metabolites; deep subseafloor fungi; solid-state fermentation