title: Antimicrobial Activity of Monoramnholipids Produced by Bacterial Strains Isolated from the Ross Sea (Antarctica).
abstract: Microorganisms living in extreme environments represent a huge reservoir of novel antimicrobial compounds and possibly of novel chemical families. Antarctica is one of the most extraordinary places on Earth and exhibits many distinctive features. Antarctic microorganisms are well known producers of valuable secondary metabolites. Specifically, several Antarctic strains have been reported to inhibit opportunistic human pathogens strains belonging to Burkholderia cepacia complex (Bcc). Herein, we applied a biodiscovery pipeline for the identification of anti-Bcc compounds. Antarctic sub-sea sediments were collected from the Ross Sea, and used to isolate 25 microorganisms, which were phylogenetically affiliated to three bacterial genera (Psychrobacter, Arthrobacter, and Pseudomonas) via sequencing and analysis of 16S rRNA genes. They were then subjected to a primary cell-based screening to determine their bioactivity against Bcc strains. Positive isolates were used to produce crude extracts from microbial spent culture media, to perform the secondary screening. Strain Pseudomonas BNT1 was then selected for bioassay-guided purification employing SPE and HPLC. Finally, LC-MS and NMR structurally resolved the purified bioactive compounds. With this strategy, we achieved the isolation of three rhamnolipids, two of which were new, endowed with high (MIC < 1 μg/mL) and unreported antimicrobial activity against Bcc strains.
authors.affiliation: Institute of Protein Biochemistry, National Research Council, Via P. Castellino, 111, I-80131 Naples, Italy. p.tedesco@ibp.cnr.it.
authors.forename: Pietro
authors.initials: P
authors.lastname: Tedesco
authors.affiliation: Department of Biology, University of Florence, Via Madonna del Piano 6, I-50019 Sesto Fiorentino (FI), Italy. isabel.maida@unifi.it.
authors.forename: Isabel
authors.initials: I
authors.lastname: Maida
authors.affiliation: Institute of Protein Biochemistry, National Research Council, Via P. Castellino, 111, I-80131 Naples, Italy. f.palma@ibp.cnr.it.
authors.forename: Fortunato
authors.initials: F
authors.lastname: Palma Esposito
authors.affiliation: Institute of Protein Biochemistry, National Research Council, Via P. Castellino, 111, I-80131 Naples, Italy. e.tortorella@ibp.cnr.it.
authors.forename: Emiliana
authors.initials: E
authors.lastname: Tortorella
authors.affiliation: Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Old Aberdeen, AB24 3UE Scotland, UK. k.subko.11@aberdeen.ac.uk.
authors.forename: Karolina
authors.initials: K
authors.lastname: Subko
authors.affiliation: Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Old Aberdeen, AB24 3UE Scotland, UK. chidinma.christiana.ezeofor.14@aberdeen.ac.uk.
authors.forename: Chidinma Christiana
authors.initials: CC
authors.lastname: Ezeofor
authors.affiliation: Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Old Aberdeen, AB24 3UE Scotland, UK. ying.zhang.14@aberdeen.ac.uk.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Old Aberdeen, AB24 3UE Scotland, UK. j.tabudravu@abdn.ac.uk.
authors.forename: Jioji
authors.initials: J
authors.lastname: Tabudravu
authors.affiliation: Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Old Aberdeen, AB24 3UE Scotland, UK. m.jaspars@abdn.ac.uk.
authors.forename: Marcel
authors.initials: M
authors.lastname: Jaspars
authors.affiliation: Department of Biology, University of Florence, Via Madonna del Piano 6, I-50019 Sesto Fiorentino (FI), Italy. renato.fani@unifi.it.
authors.forename: Renato
authors.initials: R
authors.lastname: Fani
authors.affiliation: Institute of Protein Biochemistry, National Research Council, Via P. Castellino, 111, I-80131 Naples, Italy. d.depascale@ibp.cnr.it.
authors.forename: Donatella
authors.initials: D
authors.lastname: de Pascale
mesh_terms: D000864:Antarctic Regions; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D001173:Arthrobacter / Q000737:chemistry / Q000235:genetics; D042602:Burkholderia cepacia complex / Q000737:chemistry / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics; D008055:Lipids / Q000737:chemistry* / Q000494:pharmacology*; D010802:Phylogeny; D011549:Pseudomonas / Q000737:chemistry / Q000235:genetics; D044096:Psychrobacter / Q000737:chemistry / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D008055:Lipids; D012336:RNA, Ribosomal, 16S
keywords: Antarctic; Bcc; antimicrobials; microorganisms; ramnholipids