title: Linear and cyclic peptides from the entomopathogenic bacterium Xenorhabdus nematophilus.
abstract: Three new peptides, xenortides A and B and xenematide, were isolated from a culture of the nematode-associated entomopathogenic bacterium Xenorhabdus nematophilus. Their structures were elucidated using NMR, MS, and chemical derivatization methods. Xenortides A and B are the N-phenethylamide and tryptamide derivatives, respectively, of the dipeptide (NMe-L-Leu-NMe-L-Phe). The cyclodepsipeptide xenematide has the sequence (Thr-Trp-Trp-Gly), with a 2-phenylacetamide substituent at the threonine residue and one d-tryptophan. The new peptides and the two known compounds xenocoumacin II and nematophin were tested for antibacterial, antifungal, insecticidal, and anti-Artemia salina activities. Xenematide and xenocoumacin II showed moderate antibacterial activities. Xenocoumacin II, nematophin, and the two xenortides were active in the Artemia salina assay, and xenematide acted weakly insecticidal.
authors.affiliation: Kieler Wirkstoffzentrum am IFM-GEOMAR, Am Kiel-Kanal 44, 24106 Kiel, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Lang
authors.forename: Tim
authors.initials: T
authors.lastname: Kalvelage
authors.forename: Arne
authors.initials: A
authors.lastname: Peters
authors.forename: Jutta
authors.initials: J
authors.lastname: Wiese
authors.forename: Johannes F
authors.initials: JF
authors.lastname: Imhoff
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001156:Artemia / Q000187:drug effects; D047630:Depsipeptides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D004151:Dipeptides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D007306:Insecticides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D009536:Niacinamide / Q000031:analogs & derivatives; D014363:Tryptamines; D020593:Xenorhabdus / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D047630:Depsipeptides; D004151:Dipeptides; D007306:Insecticides; D014363:Tryptamines; C531271:xenematide; C531269:xenortide A; C531270:xenortide B; D009536:Niacinamide; C057564:tryptamide