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Analysis of bacterial lipodepsipeptides by matrix‐assisted laser desorption/ionisation time‐of‐flight and high‐performance liquid chromatography with electrospray mass spectrometry
Author(s) -
Monti Simona Maria,
Gallo Monica,
Ferracane Rosalia,
Borrelli Rosa Cinzia,
Ritieni Alberto,
Greco Maria Luigia,
Graniti Antonio,
Fogliano Vincenzo
Publication year - 2001
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.277
Subject(s) - chemistry , mass spectrometry , pseudomonas syringae , chromatography , electrospray , metabolite , pseudomonas , electrospray ionization , bacteria , time of flight mass spectrometry , high performance liquid chromatography , ion , ionization , biochemistry , biology , organic chemistry , genetics , gene
Abstract Strains of certain plant pathogenic bacteria, in particular several pathovars of Pseudomonas syringae , are known to produce cyclic lipodepsipeptides (LDPs) endowed with peculiar structural features and noticeable biological activities. In this study, a mass spectrometry procedure is proposed for screening LDP‐producing bacterial strains and for identifying and assessing individual LDPs. After matrix‐assisted laser desorption/ionisation time‐of‐flight (MALDI‐TOF) screening of thirteen P. syringae strains for LDP production, the extracts from culture filtrates of eight positive strains were subjected to electrospray mass spectrometry for the identification of LDPs. Five strains were found to produce two forms of syringomycins (SR‐E and SR‐G) and two forms of syringopeptin 25 (SP 25A and SP 25B ); two strains produced SR‐E, SR‐G and a new form of SP 22 ; one strain produced syringotoxin (ST) and syringostatin A (SS‐A) in addition to SP 25A and SP 25B . The yield in culture of two major LPDs: SR‐G (3.2–13.8 mg L −1 ) and SP 25A (41.6–231.5 mg L −1 ) was assessed by and high‐performance liquid chromatography with electrospray mass spectrometry (HPLC/ESI‐MS) in both scan and single ion monitoring (SIM) modes. Results of this investigation showed that the mass spectrometry protocol developed here is a precise and reliable method for screening bacterial strains for LDP production and for assessing the amount of each metabolite under various culture conditions. This could be of practical value in view of potential applications, e.g. biocontrol of post‐harvest fungal diseases. Copyright © 2001 John Wiley & Sons, Ltd.