title: Ion trap MS(n) for identification of gliotoxin as the cytotoxic factor of a marine strain of Aspergillus fumigatus Fresenius.
abstract: When cultured in a marine solid medium, a strain of Aspergillus fumigatus (Fresenius) isolated from a shellfish-farming area in the Loire estuary (France) produced a highly cytotoxic exudate. To identify the origin of this activity, a cytotoxicity test on KB cells was used to monitor the purification of the exudate, together with electrospray/ion trap/mass spectrometry (ESI/IT/MS(n)) to detect and identify the toxic compound. After three purification stages, a comparison of fullscan analyses of the last six fractions showed that a monocharged compound at m/z 349 was present only in the active fraction, corresponding to the sodium adduct of gliotoxin [C(13)H(14)N(2)O(4)S(2)+Na](+). Isotopic distribution determination showed that the m/z 349 product possessed two sulphur atoms and multi-stage fragmentation confirmed the hypothesis. MS/MS analysis exhibited the characteristic gliotoxin loss of the disulphide intracyclic bridge. MS(3) analysis revealed four main ions and confirmed the identity of the m/z 349 ion. This study points out that the combined use of a KB cells bioassay and ESI/IT/MS(n) allows a fast and very specific detection and elucidation of unidentified cytotoxic products in natural samples. This method does not require total purification, and it allowed us to report the first detection of gliotoxin production in marine conditions.
authors.affiliation: S.M.A.B.-URM 11, ISOMer-Faculté de Pharmacie, Université de Nantes, BP53508-44035 Nantes cedex 01, France.
authors.forename: O
authors.initials: O
authors.lastname: Grovel
authors.forename: Yves  François
authors.initials: Y
authors.lastname: Pouchus
authors.forename: Thibaut
authors.initials: T
authors.lastname: Robiou du Pont
authors.forename: M
authors.initials: M
authors.lastname: Montagu
authors.forename: Z
authors.initials: Z
authors.lastname: Amzil
authors.forename: Jean- François
authors.initials: J
authors.lastname: Verbist
mesh_terms: D000818:Animals; D001232:Aspergillus fumigatus / Q000737:chemistry* / Q000472:pathogenicity; D002851:Chromatography, High Pressure Liquid; D005912:Gliotoxin / Q000032:analysis* / Q000633:toxicity; D006801:Humans; D007624:KB Cells; D013058:Mass Spectrometry; D012758:Shellfish; D014871:Water Microbiology
chemical_list: D005912:Gliotoxin