Validated method for phytohormone quantification in plants.

Phytohormones are long time known as important components of signaling cascades in plant development and plant responses to various abiotic and biotic challenges. Quantifications of phytohormone levels in plants are typically carried out using GC or LC-MS/MS systems, due to their high sensitivity, specificity, and the fact that not much sample preparation is needed. However, mass spectrometer-based analyses are often affected by the particular sample type (different matrices), extraction procedure, and experimental setups, i.

Identification of Alternaria alternata mycotoxins by LC-SPE-NMR and their cytotoxic effects to soybean (Glycine max) cell suspension culture.

This present work describes the application of liquid chromatography-solid phase extraction-nuclear magnetic resonance spectroscopy to analyse Alternaria alternata crude extracts. Altenusin (1), alternariol (2), 3'-hydroxyalternariol monomethyl ether (3), and alternariol monomethyl ether (4), were separated and identified. High-resolution mass spectrometry confirmed the proposed structures.

Methyl angolensate changes in Khaya ivorensis after fungal infection.

Khaya ivorensis with and without symptoms of stem and branch cankers, caused by Botryosphaeria rhodina were examined in order to determine whether the secondary metabolites in this plant were associated with a chemical defense response. This study provides evidence that the limonoid methyl angolensate (MA) is present at higher concentrations in K. ivorensis with symptoms of stem cankers rather than in the plants without symptoms.

Analysis of alternariol and alternariol monomethyl ether on flavedo and albedo tissues of tangerines (Citrus reticulata) with symptoms of alternaria brown spot.

A method was developed for the quantification of alternariol and alternariol monomethyl ether on tangerines with and without symptoms of Alternaria brown spot disease. The method employs solid-phase extraction for cleanup, followed by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) for detection. This method was validated on flavedo (exocarp or epicarp, exterior yellow peel) and on albedo tissue (mesocarp, interior white peel).

Tandem mass spectrometry of coprogen and deferoxamine hydroxamic siderophores.

Mechanisms of fragmentation of hydroxamic siderophores are proposed comparing deuterated and nondeuterated samples. Standard siderophores (e.g.