Lipids of two species of brown algae of the genusLaminaria

Mass spectrometric characterization of aminophospholipids containing N-(2-hydroxyethyl)glycine in kombu algae extracts

RATIONALE

1,2-Diacyl-sn-glycero-3-phospho-O-[N-(2-hydroxyethyl)glycines] (PHEGs) are a class of rare aminophospholipids found specifically in brown algae, including kombu seaweed. Despite their potential importance in algal physiology, a comprehensive mass spectrometry (MS) characterization, useful to understand their biological behaviour, is still lacking.

METHODS

To establish the structural regiochemical features of PHEGs, we employed hydrophilic interaction liquid chromatography (HILIC). Following separation, the isolated band of PHEGs was analyzed using MS techniques. This included multistage tandem MS experiments, performed in both positive and negative electrospray ionization modes at low and high resolution.

RESULTS

By comparing MS/MS and MS3 spectra acquired in negative ion mode, the regiochemical rules for PHEG identification were established. The most abundant PHEG species in kombu seaweed, from both Laminaria ochroleuca (European Atlantic) and Laminaria longissima (Japan), was identified as PHEG 20:4/20:4. Less abundant species included PHEG 20:4/20:5 and hydroxylated forms of both PHEG 20:4/20:4 (i.e. 40:8;O) and 20:4/20:5 (40:9;O). The presence of a lyso PHEG 20:4 was consistently detected but at very low levels.

CONCLUSIONS

This study employed MS analysis to elucidate the regiochemical patterns of PHEGs in kombu seaweed. We identified PHEG 20:4/20:4 as the dominant species, along with several less abundant variants, including hydroxylated forms. These findings provide valuable insights into the potential roles and metabolism of PHEGs in brown algae, paving the way for further investigation into their biological functions.

Bioprospecting of Marine Macrophytes Using MS-Based Lipidomics as a New Approach

The marine environment supports a remarkable diversity of organisms which are a potential source of natural products with biological activities. These organisms include a wide variety of marine plants (from micro- to macrophytes), which have been used in the food and pharmaceutical industry. However, the biochemistry and biological activities of many of these macrophytes (namely macroalgae and halophytes, including seagrasses) are still far from being fully explored. Most popular bioactive components include polysaccharides, peptides, phenolics and fatty acids (FAs). Polar lipids (glycolipids, phospholipids and betaine lipids) are emerging as novel value-added bioactive phytochemicals, rich in n-3 FA, with high nutritional value and health beneficial effects for the prevention of chronic diseases. Polar lipids account various combinations of polar groups, fatty acyl chains and backbone structures. The polar lipidome of macrophytes is remarkably diverse, and its screening represents a significant analytical challenge. Modern research platforms, particularly mass spectrometry (MS)-based lipidomic approaches, have been recently used to address this challenge and are here reviewed. The application of lipidomics to address lipid composition of marine macrophytes will contribute to the stimulation of further research on this group and foster the exploration of novel applications.

Release of volatile aldehydes by the brown algal kelp Laminaria digitata in response to both biotic and abiotic stress

With a little kelp from my friends: In response to biotic and abiotic stress, the brown algal kelp Laminaria digitata releases volatile fatty acid aldehydes under laboratory conditions and in its natural environment (red). In response to 4-HHE treatment, L. digitata releases (13S)-HOTrE (green). These results support the hypothesis that these compounds may mediate kelp responses to stress.