Feature-based molecular networking-guided discovery of siderophores from a marine mesophotic zone Axinellida sponge-associated actinomycete Streptomyces diastaticus NBU2966

Flavan-3-ol B-ring fission derivatives (FBRFDs) are secondary metabolites that contribute to the unique properties of fermented dark teas. However, the FBRFD precursors and biochemistry are unclear. Fungal strains cultured from Fuzhuan brick tea (FBT) were incubated in an in vitro solid-state fermentation system containing β-cyclodextrin-embedded epigallocatechin gallate (EGCG), a potential precursor of FBRFDs. The produced metabolites were analyzed through a combination of targeted chromatographic isolation, non-targeted spectroscopic identification, and Feature-based Molecular Networking (FBMN) in the Global Natural Products Social Molecular Networking (GNPS) platform. Dihydromyricetin was identified for the first time, indicating that fungi possess a flavan-3-ol C-ring oxidation pathway. EGCG was verified as the precursor of dihydromyricetin and FBRFDs such as teadenol A and fuzhuanin A. The conversion was driven by the fungi rather than a hygrothermal effect. Isolates from Pezizomycotina showed much stronger abilities to convert EGCG to the B-/C-ring oxidation products than those from Saccharomycotina or Basidiomycota.

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Feature-based molecular networking in the GNPS analysis environment

Nature Methods ◽

10.1038/s41592-020-0933-6 ◽

2020 ◽

Vol 17 (9) ◽

pp. 905-908 ◽

Cited By ~ 22

Author(s):

Louis-Félix Nothias ◽

Daniel Petras ◽

Robin Schmid ◽

Kai Dührkop ◽

Johannes Rainer ◽

...

Keyword(s):

Molecular Networking ◽

Feature Based ◽

Analysis Environment

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Feature-Based Molecular Networking to Target the Isolation of New Caffeic Acid Esters from Yacon (Smallanthus sonchifolius, Asteraceae)

Metabolites ◽

10.3390/metabo10100407 ◽

2020 ◽

Vol 10 (10) ◽

pp. 407

Author(s):

Guillermo F. Padilla-González ◽

Nicholas J. Sadgrove ◽

Gari V. Ccana-Ccapatinta ◽

Olga Leuner ◽

Eloy Fernandez-Cusimamani

Keyword(s):

Mass Spectrometry ◽

Caffeic Acid ◽

High Resolution Mass Spectrometry ◽

Chemical Diversity ◽

Bioactive Metabolites ◽

Molecular Networking ◽

Smallanthus Sonchifolius ◽

Feature Based ◽

Caffeic Acid Esters ◽

Acid Esters

Smallanthus sonchifolius (yacon) is an edible tuberous Andean shrub that has been included in the diet of indigenous people since before recorded history. The nutraceutical and medicinal properties of yacon are widely recognized, especially for the improvement of hyperglycemic disorders. However, the chemical diversity of the main bioactive series of caffeic acid esters has not been explored in detail. In this metabolomics study, we applied the latest tools to facilitate the targeted isolation of new caffeic acid esters. Using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), we analyzed extracts from different organs (roots, vascular tissues of the stems, stem epidermis, leaves, bracts, and ray flowers) and followed a feature-based molecular networking approach to characterize the structural diversity of caffeic acid esters and recognize new compounds. The analysis identified three potentially new metabolites, one of them confirmed by isolation and full spectroscopic/spectrometric assignment using nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HRMS), and MS/MS. This metabolite (5-O-caffeoyl-2,7-anhydro-d-glycero-β-d-galacto-oct-2-ulopyranosonic acid), along with eight known caffeic acid esters, was isolated from the roots and stems. Furthermore, based on detailed tandem MS analyses, we suggest that the two isomeric monocaffeoyl-2,7-anhydro-2-octulopyranosonic acids found in yacon can be reliably distinguished based on their characteristic MS2 and MS3 spectra. The outcome of the current study confirms the utility of feature-based molecular networking as a tool for targeted isolation of previously undescribed metabolites and reveals the full diversity of potentially bioactive metabolites from S. sonchifolius.

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Feature-Based Molecular Networking—An Exciting Tool to Spot Species of the Genus Cortinarius with Hidden Photosensitizers

Metabolites ◽

10.3390/metabo11110791 ◽

2021 ◽

Vol 11 (11) ◽

pp. 791

Author(s):

Fabian Hammerle ◽

Luis Quirós-Guerrero ◽

Adriano Rutz ◽

Jean-Luc Wolfender ◽

Harald Schöbel ◽

...

Keyword(s):

Mass Spectrometry ◽

High Resolution ◽

Tandem Mass ◽

Molecular Networking ◽

Defense Strategies ◽

Feature Based ◽

Phylogenetic Lineages ◽

Promising Source ◽

Fungal Extracts

Fungi have developed a wide array of defense strategies to overcome mechanical injuries and pathogen infections. Recently, photoactivity has been discovered by showing that pigments isolated from Cortinarius uliginosus produce singlet oxygen under irradiation. To test if this phenomenon is limited to dermocyboid Cortinarii, six colourful Cortinarius species belonging to different classical subgenera (i.e., Dermocybe, Leprocybe, Myxacium, Phlegmacium, and Telamonia) were investigated. Fungal extracts were explored by the combination of in vitro photobiological methods, UHPLC coupled to high-resolution tandem mass spectrometry (UHPLC-HRMS2), feature-based molecular networking (FBMN), and metabolite dereplication techniques. The fungi C. rubrophyllus (Dermocybe) and C. xanthophyllus (Phlegmacium) exhibited promising photobiological activity in a low concentration range (1–7 µg/mL). Using UHPLC-HRMS2-based metabolomic tools, the underlying photoactive principle was investigated. Several monomeric and dimeric anthraquinones were annotated as compounds responsible for the photoactivity. Furthermore, the results showed that light-induced activity is not restricted to a single subgenus, but rather is a trait of Cortinarius species of different phylogenetic lineages and is linked to the presence of fungal anthraquinones. This study highlights the genus Cortinarius as a promising source for novel photopharmaceuticals. Additionally, we showed that putative dereplication of natural photosensitizers can be done by FBMN.

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Assessing soil organic matter features under drought and normal conditions using direct infusion high resolution mass spectrometry and LC-MS/MS feature based molecular networking

10.7185/gold2021.8181 ◽

2021 ◽

Author(s):

Nicole DiDonato ◽

Noah Sokol ◽

Albert Rivas Ubach ◽

Chaevien Clendinen ◽

Nikola Tolic ◽

...

Keyword(s):

Mass Spectrometry ◽

Organic Matter ◽

Soil Organic Matter ◽

High Resolution ◽

High Resolution Mass Spectrometry ◽

Direct Infusion ◽

Molecular Networking ◽

High Resolution Mass ◽

Feature Based ◽

Resolution Mass

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New Tricks with an Old Sponge: Feature-Based Molecular Networking Led to Fast Identification of New Stylissamide L from Stylissa caribica

Marine Drugs ◽

10.3390/md18090443 ◽

2020 ◽

Vol 18 (9) ◽

pp. 443

Author(s):

Silvia Scarpato ◽

Roberta Teta ◽

Gerardo Della Sala ◽

Joseph R. Pawlik ◽

Valeria Costantino ◽

...

Keyword(s):

Cyclic Peptides ◽

Growth Inhibitor ◽

Significant Activity ◽

Amino Acid Residues ◽

Nmr Studies ◽

Molecular Networking ◽

A Cell ◽

Feature Based ◽

The Right ◽

New Compounds

Feature-based molecular networking was used to re-examine the secondary metabolites in extracts of a very well studied marine sponge, Stylissa caribica, known to contain a large array of cyclic peptides and brominated alkaloids. The analysis revealed the presence of 13 cyclic peptides in the sponge that had never been detected in previous work and appeared to be new compounds. The most abundant one was isolated and shown to be a new proline-rich cyclic heptapetide that was called stylissamide L (1). Structure of compound 1, including the cis/trans geometry of the three proline residues, was determined by extensive NMR studies; the l configuration of the seven amino acid residues was determined using Marfey’s method. Stylissamide L was tested for activity as a cell growth inhibitor and cell migration inhibitor on two cancer cell lines but, unlike other members of the stylissamide family, it showed no significant activity. This approach showed that even a thoroughly studied species such as S. caribica may contain new chemistry that can be revealed if studied with the right tools.

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