Assessment of the effects of As(III) treatment on cyanobacteria lipidomic profiles by LC-MS and MCR-ALS

Abstract

Cyanobacteria are a group of photosynthetic, nitrogen-fixing bacteria present in a wide variety of habitats such as freshwater, marine, and terrestrial ecosystems. In this work, the effects of As(III), a major toxic environmental pollutant, on the lipidomic profiles of two cyanobacteria species (Anabaena and Planktothrix agardhii) were assessed by means of a recently proposed method based on the concept of regions of interest (ROI) in liquid chromatography mass spectroscopy (LC-MS) together with multivariate curve resolution alternating least squares (MCR-ALS). Cyanobacteria were exposed to two concentrations of As(III) for a week, and lipid extracts were analyzed by ultrahigh-performance liquid chromatography/time-of-flight mass spectrometry in full scan mode. The data obtained were compressed by means of the ROI strategy, and the resulting LC-MS data sets were analyzed by the MCR-ALS method. Comparison of profile peak areas resolved by MCR-ALS in control and exposed samples allowed the discrimination of lipids whose concentrations were changed due to As(III) treatment. The tentative identification of these lipids revealed an important reduction of the levels of some galactolipids such as monogalactosyldiacylglycerol, the pigment chlorophyll a and its degradation product, pheophytin a, as well as carotene compounds such as 3-hydroxycarotene and carotene-3,3'-dione, all of these compounds being essential in the photosynthetic process. These results suggested that As(III) induced important changes in the composition of lipids of cyanobacteria, which were able to compromise their energy production processes. Graphical abstract Steps of the proposed LC-MS + MCR-ALS procedure.

Phenotypic and lipidomic characterization of primary human epidermal keratinocytes exposed to simulated solar UV radiation

“…First, a data compression step based on the Regions of Interest (ROI) concept [17], and second, the analysis of the compressed data using Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) [18] methodology. This combined approach (ROIMCR) has been successfully used in different untargeted metabolomics investigations on LC-MS data [19][20][21][22].…”

“…In the first compression step, the ROI procedure searches for signals at m/z values with significant intensity MS values, higher than a threshold value (estimated from the instrumental noise level). Apart from having higher values than the threshold value, ROI values have also to be represented by a minimum of consecutive data points in the chromatogram, within a predefined m/z deviation error (related to the MS instrument mass accuracy) [19][20][21][22]. ROI compression step takes advantage of the sparse structure of the measured MS data reducing considerably the computer storage and computation time needed without losing the instrumental mass accuracy and resolution.…”

“…This method allowed the simultaneous resolution of all the elution and MS spectral profiles of the different sample lipid constituents [24,25]. MCR-ALS has been previously applied for the resolution of the elution and spectral profiles of the constituents of complex sample mixtures analysed by LC-MS and it has been extended more recently to omic studies [16,[26][27][28][29][30][31][32].…”

Investigating the Uptake of Arsenate by Chlamydomonas reinhardtii Cells and its Effect on their Lipid Profile using Single Cell ICP–MS and Easy Ambient Sonic-Spray Ionization–MS

“…Among the most common methods for lipid analysis and profiling of cells are mass spectrometric techniques coupled to either liquid (LC–MS) − or gas chromatography (GC–MS). − Despite the high sensitivity and quantitative accuracy of these techniques, lipids must be extracted from cells in a time-consuming sample preparation procedure. Other methods that require fewer sample preparation steps include single cell matrix-assisted laser desorption ionization mass spectrometry (SC-MALDI–MS) and ambient ionization techniques such as desorption electrospray ionization mass spectrometry (DESI–MS), − nano-DESI–MS , and easy ambient sonic-spray ionization mass spectrometry (EASI–MS, also known as desorption sonic-spray ionization mass spectrometry, DeSSI–MS).…”

Stoichiometric gene-to-reaction associations enhance model-driven analysis performance: Metabolic response to chronic exposure to Aldrin in prostate cancer

“…The resulting chromatogram matrix was compressed by applying regio-of-interest (ROI) strategy [33] together with multivariate curve resolution alternating least squares (MCR-ALS) [34], as previously described in Marques A.S. et al 2016 [35]. In brief, ROI approach imposes multiple criteria to compress the data matrix with no loss of information.…”