Ángeles Fernández-Recamales

Investigation of the effect of genotype and agronomic conditions on metabolomic profiles of selected strawberry cultivars with different sensitivity to environmental stress

Strawberry is one of the most economically important and widely cultivated fruit crops across the world, so that there is a growing need to develop new analytical methodologies for the authentication of variety and origin, as well as the assessment of agricultural and processing practices. In this work, an untargeted metabolomic strategy based on gas chromatography mass spectrometry (GC-MS) combined with multivariate statistical techniques was used for the first time to characterize the primary metabolome of different strawberry cultivars and to study metabolite alterations in response to multiple agronomic conditions. For this purpose, we investigated three varieties of strawberries with different sensitivity to environmental stress (Camarosa, Festival and Palomar), cultivated in soilless systems using various electrical conductivities, types of coverage and substrates. Metabolomic analysis revealed significant alterations in primary metabolites between the three strawberry cultivars grown under different crop conditions, including sugars (fructose, glucose), organic acids (malic acid, citric acid) and amino acids (alanine, threonine, aspartic acid), among others. Therefore, it could be concluded that GC-MS based metabolomics is a suitable tool to differentiate strawberry cultivars and characterize metabolomic changes associated with environmental and agronomic conditions.

Metabolomics in Alzheimer’s disease: The need of complementary analytical platforms for the identification of biomarkers to unravel the underlying pathology

Alzheimers disease is a complex neurodegenerative disorder characterized by a multi-factorial etiology, not completely understood to date. In this context, the application of metabolomics is emerging in the last years because of its potential to monitor molecular alterations associated with disease pathogenesis and progression, as well as to discover candidate diagnostic biomarkers. However, the huge heterogeneity and dynamism of the human metabolome makes impossible the simultaneous determination of the entire set of metabolites from complex biological samples. Thus, the most common strategy to get a comprehensive overview of the organisms phenotypic expression is the combined use of complementary metabolomic platforms. In this review, we summarize the advantages and limitations of the most important analytical techniques usually employed in metabolomics, including nuclear magnetic resonance, direct infusion mass spectrometry and hyphenated approaches based on the coupling of orthogonal separation mechanisms (i.e. liquid chromatography, gas chromatography, capillary electrophoresis) with mass spectrometry. Moreover, the suitability of metabolomics to unravel the complex pathology underlying to Alzheimers disease is also presented.

Nutritional and nutraceutical quality of strawberries in relation to harvest time and crop conditions.

Three strawberry varieties cultivated in soilless systems were studied for their content of primary and secondary metabolites in relation to harvest time and crop conditions. The three varieties were chosen based on their sensitivity level to environmental stress: Palomar (very sensitive), Festival (sensitive), and Camarosa (resistant). Throughout the campaign, three samplings were performed: December (extra-early production), January, and March (early production). Differences among cultivars and harvest times were observed based on the contents of sugars, organic acids, phenolic compounds, and antioxidant capacity. The higher levels for total anthocyanins and flavan-3-ols were found in Camarosa and Festival strawberries, both in the January harvest. The Palomar variety showed higher total sugar/total organic acids ratio in the March harvest. The influence of cultivation practices and environmental conditions was assessed by nested ANOVA and PLS-DA. Differences in the sugar and phenolic content were observed depending upon variety and coverage type. TEAC was most influenced by the substrate type.

An Overview on the Importance of Combining Complementary Analytical Platforms in Metabolomic Research

The analytical bias introduced by most of the commonly used techniques in metabolomics considerably hinders the simultaneous detection of all metabolites present in complex biological samples. In order to solve this limitation, the combination of complementary approaches is emerging in recent years as the most suitable strategy in order to maximize metabolite coverage. This review article presents a general overview of the most important analytical techniques usually employed in metabolomics: nuclear magnetic resonance, mass spectrometry and hybrid approaches. Furthermore, we emphasize the potential of integrating various tools in the form of metabolomic multi-platforms in order to get a deeper metabolome characterization, for which a revision of the existing literature in this field is provided. This review is not intended to be exhaustive but, rather, to give a practical and concise guide to readers not familiar with analytical chemistry on the considerations to account for the proper selection of the technique to be used in a metabolomic experiment in biomedical research.

Mass Spectrometry-Based Metabolomic Multiplatform for Alzheimer’s Disease Research

The integration of complementary analytical platforms has emerged as a suitable strategy to perform a comprehensive metabolomic characterization of complex biological systems. In this work, we describe the most important issues to be considered for the application of a mass spectrometry multiplatform in Alzheimers disease research, which combines direct analysis with electrospray and atmospheric pressure photoionization sources, as well as orthogonal hyphenated approaches based on reversed-phase ultrahigh-performance liquid chromatography and gas chromatography. These procedures have been optimized for the analysis of multiple biological samples from human patients and transgenic animal models, including blood serum, various brain regions (e.g., hippocampus, cortex, cerebellum, striatum, olfactory bulbs), and other peripheral organs (e.g., liver, kidney, spleen, thymus). It is noteworthy that the metabolomic pipeline here detailed has demonstrated a great potential for the investigation of metabolic perturbations underlying Alzheimers disease pathogenesis.

Combination of complementary data mining methods for geographical characterization of extra virgin olive oils based on mineral composition

This work explores the potential of multi-element fingerprinting in combination with advanced data mining strategies to assess the geographical origin of extra virgin olive oil samples. For this purpose, the concentrations of 55 elements were determined in 125 oil samples from multiple Spanish geographic areas. Several unsupervised and supervised multivariate statistical techniques were used to build classification models and investigate the relationship between mineral composition of olive oils and their provenance. Results showed that Spanish extra virgin olive oils exhibit characteristic element profiles, which can be differentiated on the basis of their origin in accordance with three geographical areas: Atlantic coast (Huelva province), Mediterranean coast and inland regions. Furthermore, statistical modelling yielded high sensitivity and specificity, principally when random forest and support vector machines were employed, thus demonstrating the utility of these techniques in food traceability and authenticity research.

High-Throughput Direct Mass Spectrometry-Based Metabolomics to Characterize Metabolite Fingerprints Associated with Alzheimer’s Disease Pathogenesis

Direct mass spectrometry-based metabolomics has been widely employed in recent years to characterize the metabolic alterations underlying Alzheimer’s disease development and progression. This high-throughput approach presents great potential for fast and simultaneous fingerprinting of a vast number of metabolites, which can be applied to multiple biological matrices including serum/plasma, urine, cerebrospinal fluid and tissues. In this review article, we present the main advantages and drawbacks of metabolomics based on direct mass spectrometry compared with conventional analytical techniques, and provide a comprehensive revision of the literature on the use of these tools in the investigation of Alzheimer’s disease.

Optimization of Growth and Carotenoid Production by Haloferax mediterranei Using Response Surface Methodology

Haloferax mediterranei produces C50 carotenoids that have strong antioxidant properties. The response surface methodology (RSM) tool helps to accurately analyze the most suitable conditions to maximize C50 carotenoids production by haloarchaea. The effects of temperature (15–50 °C), pH (4−10), and salinity (5–28% NaCl (w/v)) on the growth and carotenoid content of H. mediterranei were analyzed using the RSM approach. Growth was determined by measuring the turbidity at 600 nm. To determine the carotenoid content, harvested cells were lysed by freeze/thawing, then re-suspended in acetone and the total carotenoid content determined by measuring the absorbance at 494 nm. The analysis of carotenoids was performed by an HPLC system coupled with mass spectrometry. The results indicated the theoretical optimal conditions of 36.51 or 36.81 °C, pH of 8.20 or 8.96, and 15.01% or 12.03% (w/v) salinity for the growth of haloarchaea (OD600 = 12.5 ± 0.64) and production of total carotenoids (3.34 ± 0.29 mg/L), respectively. These conditions were validated experimentally for growth (OD600 = 13.72 ± 0.98) and carotenoid production (3.74 ± 0.20 mg/L). The carotenoid profile showed four isomers of bacterioruberin (89.13%). Our findings suggest that the RSM approach is highly useful for determining optimal conditions for large-scale production of bacterioruberin by haloarchaea.

NMR Fingerprint to Classify Spanish Olive Varieties

Traditionally the analysis of vegetable oils has been carried out by classic procedures such as gas chromatography, which requires previous derivatization of the sample. This, involves the consumption of reagents and, sometimes, the composition of the sample could be altered with the corresponding error in the measurement. Therefore, it is desirable to use faster and environmental friendly techniques that do not require manipulation of the sample. In this sense, the spectroscopic techniques are an alternative. Specifically, nuclear magnetic resonance (NMR) spectroscopy can be used in the field of olive oil to measure some of its characteristics (eg fatty acids, phenols, hydrocarbons, etc.). The aim of this work have been to study the difference between samples of extra virgin olive oil of different varieties (picual, arbequina and verdial), based on the information provided by the 1H and 13C spectra. The chemical shifts of the spectra were referenced with respect to tetramethylsilane, using the deuterated solvent signal as internal reference. The data obtained have been treated by multivariate statistical analysis procedures (Multiple Analysis of Variance (MANOVA) and Principal Component Analysis (PCA)) to establish relations that have been interpreted from a chemical point of view and have allowed the discrimination of samples according to their variety.

TARGET METABOLOMIC APPROACH LOOKING FOR BETTER STRAWBERRY GROWING CONDITIONS TO ENHANCE BIOACTIVE CONTENT.

In recent years, interest in phenolic compounds has been increased due mainly to the numerous evidences of its beneficial health effects and their impact on food quality. Numerous efforts have been made in order to increase the knowledge about phenolic compounds, with an especial focus on characterization of new food sources rich in polyphenols. There has been studied the influence of different factors such as variety, pedoclimatic conditions, geographical origin, authenticity and traceability, among others on their contents, as a tool for enhancing nutritional and nutraceutical quality of plant derived foods in breeding programs.The objective of the present study was to assess whether growth under controlled condition could be used for cultivation of strawberry to enhance bioactive polyphenols content. For this purpose, 54 samples of strawberries belonging to three varieties with different sensitivity to environmental conditions (Camarosa, Festival, Palomar) were grown in soilless system with different agronomic conditions (electrical conductivity, substrate type and coverage).UHPLC-ESI-MS / MS analysis of polyphenolic compounds combined with chemometric methods revealed that benzoic acids, cinnamic acids, flavan-3-ol and antioxidant activity were significantly influenced (p <0.001) by coverage and variety. In addition, it was observed that the substrate has a significant effect on flavonols, whereas the variety affects the content of ellagic acid and its derivatives as well as in anthocyanins.