Chemotaxonomic Fingerprinting of Chilean Lichens Through Maldi and Electrospray Ionization Mass Spectrometry

Abstract

The aim of this work was to study a fast, new, sensitive, and simple method for the chemotaxonomic classification of Chilean lichens (Teloschistes chrysophthalmus, Ramalina farinacea, Usnea pusilla, Ramalina chilensis and Stereocaulon ramulosum) using MALDI-TOF-MS and UPLC-ESI(-)-MS data. Lichens soluble proteins fingerprints were acquired by MALDI-TOF-MS and they were analyzed by chemometric (PCA). Lichens organic extracts fingerprints were obtained by UPLC-ESI(-)-MS. MALDI-TOF-MS associated with chemometric analysis was used to detect new m/z patterns of soluble proteins that were compared with Protein Data Bank of UnitPro. These data also permitted the satisfactory distinction among the families and species. UPLC-ESI(-)-MS fingerprints analyses of the organic extracts showed the presence of five major lichen compounds (atranorin, parietin, teloschistin, ramalinolic and usnic acids). In contrast to other techniques, MALDI-TOF-MS associated with chemometric analysis and UPLC-ESI(-)-MS provided a new, fast and sensitive method for chemotaxonomic characterization of lichens.

Matrix-Free UV-Laser Desorption Ionization Mass Spectrometry as a Versatile Approach for Accelerating Dereplication Studies on Lichens

“…To the best of the authors' knowledge, the only application of laser-desorption ionization mass spectrometry on lichens is a MALDI experiment on Chilean lichens targeting the analysis of soluble proteins. 8 Many lichen compounds show close structural similarity to known MALDI matrices and may therefore exhibit similar ionization properties as recently shown for usnic acid. 7 Independently from their potential matrix effects, phenolic compounds should exhibit autoionization upon laser light exposure.…”

“…In this respect, the direct detection of lichen compounds by laser desorption ionization (LDI) represents an interesting approach that has not been studied so far. To the best of the authors’ knowledge, the only application of laser-desorption ionization mass spectrometry on lichens is a MALDI experiment on Chilean lichens targeting the analysis of soluble proteins …”

Identification of freshwater zooplankton species using protein profiling and principal component analysis

“…It is a scale‐sensitive method that often requires the use of data normalization to prevent the preference of samples with higher signal intensities. This method is commonly used in many scientific fields, such as the microbiological analyses of food (Kim et al ), the identification of intact bacteria (Santos et al 2015 b ; Bunesova et al ; Svobodova et al ), the chemotaxonomic classification of lichens (Santos et al ), and the study of ageing processes and pigment influence on binder identification in artwork (Romero‐Pastor et al ; Kuckova et al ).…”