title: Chemical and biological characterization of sclerosin, an antifungal lipopeptide.
abstract: Pseudomonas  sp. strain DF41 produces a lipopeptide, called sclerosin that inhibits the fungal pathogen  Sclerotinia sclerotiorum . The aim of the current study was to deduce the chemical structure of this lipopeptide and further characterize its bioactivity. Mass spectrometry analysis determined the structure of sclerosin to be CH(3)-(CH(2))(6)-CH(OH)-CH(2)-CO-Dhb-Pro-Ala-Leu/Ile-Ala-Val-Val-Dhb-Thr-Val-Leu/Ile-Dhp-Ala-Ala-Ala-Val-Dhb-Dhb-Ala-Dab-Ser-Val-OH, similar to corpeptins A and B of the tolaasin group, differing by only 3 amino acids in the peptide chain. Subjecting sclerosin to various ring opening procedures revealed no new ions, suggesting that this molecule is linear. As such, sclerosin represents a new member of the tolaasin lipopeptide group. Incubation of S. sclerotinia ascospores and sclerotia in the presence of sclerosin inhibited the germination of both cell types. Sclerosin also exhibited antimicrobial activity against  Bacillus  species. Conversely, this lipopeptide demonstrated no zoosporicidal activity against the oomycete pathogen  Phytophthora infestans . Next, we assessed the effect of DF41 and a lipopeptide-deficient mutant on the growth and development of  Caenorhabditis elegans  larvae. We discovered that sclerosin did not protect DF41 from ingestion by and degradation in the C. elegans digestive tract. However, another metabolite produced by this bacterium appeared to shorten the life-span of the nematode compared to C. elegans growing on Escherichia coli OP50.
authors: Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
authors: Chrystal L
authors: CL
authors: Berry
authors: Ann Karen C
authors: AK
authors: Brassinga
authors: Lynda J
authors: LJ
authors: Donald
authors: W G Dilantha
authors: WG
authors: Fernando
authors: Peter C
authors: PC
authors: Loewen
authors: Teresa R
authors: TR
authors: de Kievit
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology; D000935:Antifungal Agents / Q000737:chemistry*; D001407:Bacillus / Q000187:drug effects; D017173:Caenorhabditis elegans / Q000187:drug effects; D007814:Larva / Q000187:drug effects; D055666:Lipopeptides / Q000737:chemistry* / Q000494:pharmacology*; D013058:Mass Spectrometry; D011549:Pseudomonas / Q000737:chemistry
chemical_list: D000890:Anti-Infective Agents; D000935:Antifungal Agents; D055666:Lipopeptides