Este trabajo fue apoyado por los alimentos para la salud descubrimiento temático en la Universidad Estatal de Ohio y el Departamento de Ciencia y Tecnología de Alimentos de la Universidad Estatal de Ohio. Los autores desean agradecer a las instalaciones de RMN en la Universidad Estatal de Ohio y la facilidad de RMN en la Universidad Estatal de Pensilvania.

<ol>
	<li>Simopoulos, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+importance+of+the+ratio+of+omega-6/omega-3+essential+fatty+acids.">The importance of the ratio of omega-6/omega-3 essential fatty acids.</a> Biomed. Pharmacother. 56 (8), 365-379 (2002).</li><li>Goodnight, S. H., Harris, W. S., Connor, W. 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B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standardless+1H+NMR+determination+of+pharmacologically+active+substances+in+dietary+supplements+and+medicines+that+have+been+illegally+traded+over+the+internet.">Standardless 1H NMR determination of pharmacologically active substances in dietary supplements and medicines that have been illegally traded over the internet.</a> Drug Test. Anal. 5 (6), 400-411 (2013).</li><li>Berger, S., Braun, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> 200 and more NMR experiments: a practical course. , (2004).</li><li>Knothe, G., Kenar, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+the+fatty+acid+profile+by+1H-NMRspectroscopy.">Determination of the fatty acid profile by 1H-NMRspectroscopy.</a> Eur. J. Lipid Sci. Technol. 106, 88-96 (2004).</li><li>Sacchi, R., Medina, J. I., Aubourg, S. P., Paolillo, I. G. L., Addeo, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+High-Resolution+13C+NMR+Analysis+of+Lipids+Extracted+from+the+White+Muscle+of+Atlantic+Tuna+(Thunnus+alalunga).">Quantitative High-Resolution 13C NMR Analysis of Lipids Extracted from the White Muscle of Atlantic Tuna (Thunnus alalunga).</a> J. Agric. Food Chem. 41 (8), 1247-1253 (1993).</li><li>Dais, P., Misiak, M., Hatzakis, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+marine+dietary+supplements+using+NMR+spectroscopy.">Analysis of marine dietary supplements using NMR spectroscopy.</a> Anal. Methods. 7 (12), 5226-5238 (2015).</li><li>Pickova, J., Dutta, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cholesterol+Oxidation+in+Some+Processed+Fish+Products.">Cholesterol Oxidation in Some Processed Fish Products.</a> J. Anal. Oil Chem. Soc. 80 (10), 993-996 (2003).</li><li>Siddiqui, N., Sim, J., Silwood, C. J. L., Toms, H., Iles, R. A., Grootveld, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multicomponent+analysis+of+encapsulated+marine+oil+supplements+using+high-resolution+1H+and+13C+NMR+techniques.">Multicomponent analysis of encapsulated marine oil supplements using high-resolution 1H and 13C NMR techniques.</a> J. of Lipid Rsrch. 44 (12), 2406-2427 (2003).</li><li>Sua&#180;rez, E. R., Mugford, P. F., Rolle, A. J., Burton, I. W., Walter, J. A., Kralovec, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=13C-NMR+Regioisomeric+Analysis+of+EPA+and+DHA+in+Fish+Oil+Derived+Triacylglycerol+Concentrates.">13C-NMR Regioisomeric Analysis of EPA and DHA in Fish Oil Derived Triacylglycerol Concentrates.</a> J. Am. Oil Chem. Soc. 87, 1425-1433 (2010).</li><li>Youlin, X. A., Moran, S., Nikonowiczband, E. P., Gao, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Z-restored+spin-echo+13C+1D+spectrum+of+straight+baseline+free+of+hump,+dip+and+roll.">Z-restored spin-echo 13C 1D spectrum of straight baseline free of hump, dip and roll.</a> Magn. Reson. Chem. 46, 432-435 (2008).</li><li>Tengku-Rozaina, T. M., Birch, E. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Positional+distribution+of+fatty+acids+on+hoki+and+tuna+oil+triglycerides+by+pancreatic+lipase+and+13C+NMR+analysis.">Positional distribution of fatty acids on hoki and tuna oil triglycerides by pancreatic lipase and 13C NMR analysis.</a> Eur. J. Lipid Sci. Technol. 116 (3), 272-281 (2014).</li><li>Berry, S. E. 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Los autores no tienen nada que revelar.

Modificaciones y estrategias para la solución de problemas Calidad espectral. La anchura de línea de la señal de RMN y por lo tanto la resolución del espectro de RMN depende de cuñas, que es un proceso para la optimización de la homogeneidad del campo magnético altamente. Para el análisis de rutina, 1D calce es adecuada y no se requiere un calce 3D, dado que se lleva a cabo por el personal de RMN sobre una base regular. Si este no es el caso, un calce 3D debe realizarse...

El consumo de n -3 ácidos grasos en la dieta ha demostrado ser beneficioso contra varias condiciones tales como trastornos del corazón 1, 2, 3, enfermedades inflamatorias 4 y diabetes 5. La dieta occidental es considerada pobre en ácidos grasos n -3 y por lo tanto se recomienda el consumo de suplementos de aceite de pescado para mejorar la n -6 / n -3 equilibrio en la nutrición de los consumidores 1. A pesar del reciente aumento en el consumo de suplemento de aceite de pescado, sigue habiendo dudas sobre la seguridad, la autenticidad y la calidad de algunos de estos productos. El análisis de la composición rápida y precisa de los suplementos de aceite de pescado es esencial para evaluar adecuadamente la calidad de estos productos comerciales y garantizar la seguridad del consumidor. Las metodologías más comunes para la evaluación de suplemento de aceite de pescados son la cromatografía de gases (GC) y espectroscopia infrarroja (IR). Si bien estos son métodos altamente sensibles, sufren de varios inconvenientes 6. El análisis de GC es que consume tiempo (4-8 h), ya que la separación y la derivatización de compuestos individuales se requiere 7 y la oxidación de lípidos se pueden producir durante el análisis 8, 9. Aunque la espectroscopia de IR puede ser cuantitativa, se requiere un modelo de predicción a ser construido usando regresión de mínimos cuadrados parciales (PLSR), aunque hay excepciones en el que bandas de IR puede ser atribuida a un solo compuesto 10. PLSR requiere el análisis de un gran número de muestras, lo que aumenta el tiempo del análisis 11. Por esta razón, hay un interés creciente en el desarrollo de nuevas metodologías analíticas que permiten un análisis preciso y rápido de un gran número de muestras de aceite de pescado. Organizaciones como la OfiOficina de Suplementos Dietéticos (ODS) de los Institutos Nacionales de Salud (NIH) y la Administración de Alimentos y Medicamentos (FDA) han colaborado con la Asociación de Químicos Analíticos Oficiales (AOAC) para desarrollar estos nuevos métodos 12, 13. Uno de los métodos analíticos más prometedores para la detección y la evaluación de las matrices de múltiples componentes, tales como suplementos dietéticos, es la espectroscopia de resonancia magnética nuclear (RMN) 14, 15. espectroscopía de RMN tiene varias ventajas: es una técnica no destructiva y cuantitativa, se requiere un mínimo o ningún preparación de la muestra, y se caracteriza por una excelente precisión y reproducibilidad. Además, la espectroscopía de RMN es una metodología respetuosa del medio ambiente, ya que utiliza sólo pequeñas cantidades de disolventes. El principal inconveniente de la espectroscopía de RMN es su sensibilidad relativamente baja en comparación con otros analytimétodos Cal, sin embargo, los recientes avances tecnológicos en la instrumentación, como los campos más fuertes magnéticos, sondas criogénicas de varios diámetros, procesamiento de datos avanzado, y secuencias de pulsos versátiles y técnicas han aumentado la sensibilidad hasta el rango de nM. Mientras RMN instrumentación es de alto costo, el tiempo de vida de los espectrómetros de RMN y las muchas aplicaciones de RMN reducir el costo de los análisis en el largo plazo. Este protocolo de vídeo detallada está destinada a ayudar a los nuevos practicantes en el campo evitar los errores asociados con la 1 H y 13 C RMN análisis espectroscópico de suplementos de aceite de pescado.

<table><tbody><tr><td>Avance III 850 NMR instrument</td><td>Bruker</td><td></td><td></td></tr><tr><td>Avance III 500 NMR instrument</td><td>Bruker</td><td></td><td></td></tr><tr><td>TCI 5 mm probe</td><td>Bruker</td><td></td><td>Helium cooled inverse (proton deetected) NMR probe featuring three independent channels (&lt;sup&gt;1&lt;/sup&gt;H, &lt;sup&gt;13&lt;/sup&gt;C, &lt;sup&gt;15&lt;/sup&gt;N)</td></tr><tr><td>BBO prodigy 5 mm probe</td><td>Bruker</td><td></td><td>Nitrogen cooled observe (X-nuclei detected) probe, featuring two channels; one for &lt;sup&gt;1&lt;/sup&gt;H and &lt;sup&gt;19&lt;/sup&gt;F detectionand one for X-nuclei (covering from &lt;sup&gt;15&lt;/sup&gt;N to &lt;sup&gt;31&lt;/sup&gt;P)</td></tr><tr><td>Spinner turbin</td><td>Bruker</td><td></td><td>NMR spinners are made by polymer materials and they have a rubber o-ring to hold the NMR tube securely in place</td></tr><tr><td>Topspin 3.5</td><td>Bruker</td><td></td><td></td></tr><tr><td>deuterated chloroform</td><td>Sigma-Aldrich</td><td>&amp;nbsp;865-49-6</td><td>99.8 atom % D, contains 0.03 TMS</td></tr><tr><td>2,6-Di-&lt;em&gt;tert&lt;/em&gt;-butyl-4-methylphenol</td><td>Sigma-Aldrich</td><td>&amp;nbsp;128-37-0</td><td>purity &gt;99%</td></tr><tr><td>Fish oil samples</td><td></td><td></td><td></td></tr><tr><td>NMR tubes</td><td>New Era</td><td>NE-RG5-7</td><td>5mm OD Routine &amp;ldquo;R&amp;rdquo; Series NMR Sample Tube</td></tr><tr><td>BSMS</td><td>Bruker</td><td></td><td>Bruker Systems Management System; control system device</td></tr></tbody></table>

nmr spectroscopy as a robust tool for the rapid evaluation of the lipid profile of fish oil supplements

La dieta occidental es deficiente en n -3 ácidos grasos, por lo tanto, se recomienda el consumo de suplementos de aceite de pescado para aumentar la ingesta de estos nutrientes esenciales. El objetivo de este trabajo es demostrar el análisis cualitativo y cuantitativo de los suplementos de aceite de pescado encapsuladas usando de alta resolución 1 H y 13 C espectroscopía de RMN utilizando dos instrumentos de RMN diferentes; un 500 MHz y un instrumento de 850 MHz. Tanto de protones (1 H) y carbono (13 C) Los espectros de RMN se pueden utilizar para la determinación cuantitativa de los constituyentes principales de los suplementos de aceite de pescado. Cuantificación de los lípidos en los suplementos de aceite de pescado se logra mediante la integración de las señales de RMN correspondientes en los espectros 1D relevante. Los resultados obtenidos por 1 H y 13 C RMN están en buen acuerdo con el uno al otro, a pesar de la diferencia en la resolución y la sensibilidad entre los dos núcleos y los dos instrumentos. Oferta 1 H RMNsa análisis más rápido en comparación con el 13 C RMN, como el espectro se puede grabar en menos de 1 min, en contraste con 13 análisis de RMN de C, que dura de 10 min a una hora. El espectro de RMN 13 C, sin embargo, es mucho más informativo. Puede proporcionar datos cuantitativos para un mayor número de ácidos grasos individuales y se puede utilizar para determinar la distribución posicional de los ácidos grasos en el esqueleto de glicerol. Ambos núcleos pueden proporcionar información cuantitativa en un solo experimento sin la necesidad de purificación o separación pasos. La fuerza del campo magnético afecta principalmente a los espectros de RMN 1 H debido a su menor resolución con respecto a 13 C RMN, sin embargo, los instrumentos de RMN incluso menor costo se pueden aplicar eficientemente como un método estándar por los laboratorios de la industria alimentaria y de control de calidad.

1 H y 13 espectros de RMN C se recogieron para los suplementos de aceite de pescado comercialmente disponibles utilizando dos instrumentos de RMN; un 850 MHz y un espectrómetro de 500 MHz. Estos espectros se pueden utilizar para la determinación cuantitativa de los componentes del aceite de pescado, como el ácido docosahexaenoico (DHA) y ácido eicosapentaenoico (EPA), así como otros compuestos tales como n -1 cadenas de acilo y el índice importante nu...

Watch this Scientific Journal Video about NMR Spectroscopy as a Robust Tool for the Rapid Evaluation of the Lipid Profile of Fish Oil Supplements at JoVE.com

NMR Spectroscopy as a Robust Tool for the Rapid Evaluation of the Lipid Profile of Fish Oil Supplements

Aquí, de alta resolución 1 H y 13 C de Resonancia Magnética Nuclear (RMN) se utilizó como una herramienta rápida y fiable para el análisis cuantitativo y cualitativo de suplementos de aceite de pescado encapsuladas.

Espectroscopía de RMN como una herramienta robusta para la Evaluación Rápida del perfil lipídico de los suplementos de aceite de pescado

The western diet is poor in n-3 fatty acids, therefore the consumption of fish oil supplements is recommended to increase the intake of these essential ...

nmr-spectroscopy-as-robust-tool-for-rapid-evaluation-lipid-profile

Research

JoVE Journal

Chemistry

25.9K vistas.  The Ohio State University.  Aquí, de alta resolución 1 H y 13 C de Resonancia Magnética Nuclear (RMN) se utilizó como una herramienta rápida y fiable para el análisis cuantitativo y cualitativo de suplementos de aceite de pescado encapsuladas. 

Video: NMR Spectroscopy as a Robust Tool for the Rapid Evaluation of the Lipid Profile of Fish Oil Supplements

Analysis of Fatty Acid Content and Composition in Microalgae

A method to determine the content and composition of total fatty acids present in microalgae is described. Fatty acids are a major constituent of microalgal biomass. These fatty acids can be present in different acyl-lipid classes. Especially the fatty acids present in triacylglycerol (TAG) are of commercial interest, because they can be used for production of transportation fuels, bulk chemicals, nutraceuticals (&omega;-3 fatty acids), and food commodities. To develop commercial applications, reliable analytical methods for quantification of fatty acid content and composition are needed. Microalgae are single cells surrounded by a rigid cell wall. A fatty acid analysis method should provide sufficient cell disruption to liberate all acyl lipids and the extraction procedure used should be able to extract all acyl lipid classes.
With the method presented here all fatty acids present in microalgae can be accurately and reproducibly identified and quantified using small amounts of sample (5 mg) independent of their chain length, degree of unsaturation, or the lipid class they are part of.
This method does not provide information about the relative abundance of different lipid classes, but can be extended to separate lipid classes from each other.
The method is based on a sequence of mechanical cell disruption, solvent based lipid extraction, transesterification of fatty acids to fatty acid methyl esters (FAMEs), and quantification and identification of FAMEs using gas chromatography (GC-FID). A TAG internal standard (tripentadecanoin) is added prior to the analytical procedure to correct for losses during extraction and incomplete transesterification.

A method for the determination of fatty acid content and composition in microalgae based on mechanical cell disruption, solvent based lipid extraction, transesterification, and quantification and identification of fatty acids using gas chromatography is described. A tripentadecanoin internal standard is used to compensate for the possible losses during extraction and incomplete transesterification.

Análisis de contenido de ácido graso y Composición en microalgas

A method to determine the content and composition of total fatty acids present in microalgae is described. Fatty acids are a major constituent of ...

Investigación

Medio ambiente

A Simple and Rapid Protocol for Measuring Neutral Lipids in Algal Cells Using Fluorescence

Algae are considered excellent candidates for renewable fuel sources due to their natural lipid storage capabilities. Robust monitoring of algal fermentation processes and screening for new oil-rich strains requires a fast and reliable protocol for determination of intracellular lipid content. Current practices rely largely on gravimetric methods to determine oil content, techniques developed decades ago that are time consuming and require large sample volumes. In this paper, Nile Red, a fluorescent dye that has been used to identify the presence of lipid bodies in numerous types of organisms, is incorporated into a simple, fast, and reliable protocol for measuring the neutral lipid content of Auxenochlorella protothecoides, a green alga. The method uses ethanol, a relatively mild solvent, to permeabilize the cell membrane before staining and a 96 well micro-plate to increase sample capacity during fluorescence intensity measurements. It has been designed with the specific application of monitoring bioprocess performance. Previously dried samples or live samples from a growing culture can be used in the assay.

A simple protocol to determine the neutral lipid content of algal cells using a Nile Red staining procedure is described. This time-saving technique offers an alternative to traditional gravimetric-based lipid quantification protocols. It has been designed for the specific application of monitoring bioprocess performance.

Un simple y protocolo Rapid para Medir lípidos neutros en las células de algas Utilizando Fluorescencia

Algae are considered excellent candidates for renewable fuel sources due to their natural lipid storage capabilities. Robust monitoring of algal ...

Química

Fatty Acid 13C Isotopologue Profiling Provides Insight into Trophic Carbon Transfer and Lipid Metabolism of Invertebrate Consumers

Fatty acids (FAs) are useful biomarkers in food web ecology because they are typically assimilated as a complete molecule and transferred into consumer tissue with minor or no modification, allowing the dietary routing between different trophic levels. However, the FA trophic marker approach is still hampered by the limited knowledge in lipid metabolism of the soil fauna. This study used entirely labelled palmitic acid (13C16:0, 99 atom%) as a tracer in fatty acid metabolism pathways of two widespread soil Collembola, Protaphorura fimata and Heteromurus nitidus. In order to investigate the fate and metabolic modifications of this precursor, a method of isotopologue profiling is presented, performed by mass spectrometry using single ion monitoring. Moreover, the upstream laboratory feeding experiment is described, as well as the extraction and methylation of dominant lipid fractions (neutral lipids, phospholipids) and the related formula and calculations. Isotopologue profiling does not only yield the overall 13C enrichment in fatty acids derived from the 13C labeled precursor but also produces the pattern of isotopologues exceeding the mass of the parent ion (i.e., the FA molecular ion M+) of each labeled FA by one or more mass units (M+1, M+2, M+3, etc.). This knowledge allows conclusions on the ratio of dietary routing of an entirely consumed FA in comparison to de novo biosynthesis. The isotopologue profiling is suggested as a useful tool for evaluation of fatty acid metabolism in soil animals to disentangle trophic interactions.

Fatty Acid 13C Isotopologue Profiling Provides Insight into Trophic Carbon Transfer and Lipid Metabolism of Invertebrate Consumers

The fatty acid trophic marker approach, i.e., the assimilation of fatty acids as entire molecule and transfer into consumer tissue with no or minor modification, is hampered by knowledge gaps in fatty acid metabolism of small soil invertebrates. Isotopologue profiling is provided as a valuable tool to disentangle trophic interactions.

Perfiles de ácidos grasos 13C Isotopologue proporciona una idea de la transferencia trófica de carbono y metabolismo de los lípidos de los consumidores invertebrados

Fatty acids (FAs) are useful biomarkers in food web ecology because they are typically assimilated as a complete molecule and transferred into consumer ...

Bioquímica

Single-throughput Complementary High-resolution Analytical Techniques for Characterizing Complex Natural Organic Matter Mixtures

Natural organic matter (NOM) is composed of a highly complex mixture of thousands of organic compounds which, historically, proved difficult to characterize. However, to understand the thermodynamic and kinetic controls on greenhouse gas (carbon dioxide [CO2] and methane [CH4]) production resulting from the decomposition of NOM, a molecular-level characterization coupled with microbial proteome analyses is necessary. Further, climate and environmental changes are expected to perturb natural ecosystems, potentially upsetting complex interactions that influence both the supply of organic matter substrates and the microorganisms performing the transformations. A detailed molecular characterization of the organic matter, microbial proteomics, and the pathways and transformations by which organic matter is decomposed will be necessary to predict the direction and magnitude of the effects of environmental changes. This article describes a methodological throughput for comprehensive metabolite characterization in a single sample by direct injection Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), gas chromatography mass spectrometry (GC-MS), nuclear magnetic resonance (NMR) spectroscopy, liquid chromatography mass spectrometry (LC-MS), and proteomics analysis. This approach results in a fully-paired dataset which improves statistical confidence for inferring pathways of organic matter decomposition, the resulting CO2 and CH4 production rates, and their responses to environmental perturbation. Herein we present results of applying this method to NOM samples collected from peatlands; however, the protocol is applicable to any NOM sample (e.g., peat, forested soils, marine sediments, etc.).

This protocol describes a single throughput for complementary analytical and omics techniques culminating in a fully-paired characterization of natural organic matter and microbial proteomics in different ecosystems. This approach permits robust comparisons for identifying metabolic pathways and transformations important for describing greenhouse gas production and predicting responses to environmental change.

Técnicas analíticas de alta resolución complementarias solo rendimiento para caracterizar mezclas complejas de materia orgánica Natural

Natural organic matter (NOM) is composed of a highly complex mixture of thousands of organic compounds which, historically, proved difficult to ...

Determination of Total Lipid and Lipid Classes in Marine Samples

Lipids are largely composed of carbon and hydrogen and, therefore, provide a greater specific energy than other organic macromolecules in the sea. Being carbon- and hydrogen-rich they are also hydrophobic and can act as a solvent and absorption carrier for organic contaminants and thus can be drivers of pollutant bioaccumulation in marine ecosystems. Their hydrophobic nature facilitates their isolation from seawater or biological specimens: marine lipid analysis begins with sampling and then extraction in non-polar organic solvents, providing a convenient method for their separation from other substances in an aquatic matrix.
If seawater has been sampled, the first step usually involves separation into operationally defined &#39;dissolved&#39; and &#39;particulate&#39; factions by filtration. Samples are collected and lipids isolated from the sample matrix typically with chloroform for truly dissolved matter and colloids, and with mixtures of chloroform and methanol for solids and biological specimens. Such extracts may contain several classes from biogenic and anthropogenic sources. At this time, total lipids and lipid classes may be determined. Total lipid can be measured by summing individually determined lipid classes which customarily have been chromatographically separated. Thin-layer chromatography (TLC) with flame ionization detection (FID) is regularly used for the quantitative analysis of lipids from marine samples. TLC-FID furnishes synoptic lipid class information and, by summing classes, a total lipid measurement.
Lipid class information is especially useful when combined with measurements of individual components e.g., fatty acids and/or sterols, after their release from lipid extracts. The wide variety of lipid structures and functions means they are used broadly in ecological and biogeochemical research assessing ecosystem health and the degree of influence by anthropogenic impacts. They have been employed to measure substances of dietary value to marine fauna (e.g., aquafeeds and/or prey), and as an indicator of water quality (e.g., hydrocarbons).

This protocol is for the determination of lipids in seawater and biological specimens. Lipids in filtrates are extracted with chloroform or mixtures of chloroform and methanol in the case of solids. Lipid classes are measured by rod thin-layer chromatography with flame ionization detection and their sum gives the total lipid content.

Determinación de clases totales de lípidos y lípidos en muestras marinas

Lipids are largely composed of carbon and hydrogen and, therefore, provide a greater specific energy than other organic macromolecules in the sea. Being ...

A Quantitative Assessment of The Yeast Lipidome using Electrospray Ionization Mass Spectrometry

Lipids are one of the major classes of biomolecules and play important roles membrane dynamics, energy storage, and signalling1-4. The budding yeast Saccharomyces cerevisiae, a genetically and biochemically manipulable unicellular eukaryote with annotated genome and very simple lipidome, is a valuable model for studying biological functions of various lipid species in multicellular eukaryotes2,3,5. S. cerevisiae has 10 major classes of lipids with chain lengths mainly of 16 or 18 carbon atoms and either zero or one degree of unsaturation6,7. Existing methods for lipid identification and quantification - such as high performance liquid chromatography, thin-layer chromatography, fluorescence microscopy, and gas chromatography followed by MS - are well established but have low sensitivity, insufficiently separate various molecular forms of lipids, require lipid derivitization prior to analysis, or can be quite time consuming. Here we present a detailed description of our experimental approach to solve these inherent limitations by using survey-scan ESI/MS for the identification and quantification of the entire complement of lipids in yeast cells. The described method does not require chromatographic separation of complex lipid mixtures recovered from yeast cells, thereby greatly accelerating the process of data acquisition. This method enables lipid identification and quantification at the concentrations as low as g/ml and has been successfully applied to assessing lipidomes of whole yeast cells and their purified organelles. Lipids extraction from whole yeast cells for using this method of lipid analysis takes two to three hours. It takes only five to ten minutes to run each sample of extracted and dried lipids on a Q-TOF mass spectrometer equipped with a nano-electrospray source.

We describe a new quantitative lipidomics method for identifying numerous lipid species in yeast using survey-scan electrospray ionization mass spectrometry (ESI/MS). This method exceeds currently available methods for lipid identification and quantification in the ability to resolve various molecular forms of lipids, sensitivity, and speed.

Una evaluación cuantitativa de la Lipidome levadura utilizando la espectrometría de masas de ionización por electrospray

Lipids are one of the major classes of biomolecules and play important roles membrane dynamics, energy storage, and signalling1-4. The budding yeast ...

Biología

Metabolomic Analysis of Rat Brain by High Resolution Nuclear Magnetic Resonance Spectroscopy of Tissue Extracts

Studies of gene expression on the RNA and protein levels have long been used to explore biological processes underlying disease. More recently, genomics and proteomics have been complemented by comprehensive quantitative analysis of the metabolite pool present in biological systems. This strategy, termed metabolomics, strives to provide a global characterization of the small-molecule complement involved in metabolism. While the genome and the proteome define the tasks cells can perform, the metabolome is part of the actual phenotype. Among the methods currently used in metabolomics, spectroscopic techniques are of special interest because they allow one to simultaneously analyze a large number of metabolites without prior selection for specific biochemical pathways, thus enabling a broad unbiased approach. Here, an optimized experimental protocol for metabolomic analysis by high-resolution NMR spectroscopy is presented, which is the method of choice for efficient quantification of tissue metabolites. Important strengths of this method are (i) the use of crude extracts, without the need to purify the sample and/or separate metabolites; (ii) the intrinsically quantitative nature of NMR, permitting quantitation of all metabolites represented by an NMR spectrum with one reference compound only; and (iii) the nondestructive nature of NMR enabling repeated use of the same sample for multiple measurements. The dynamic range of metabolite concentrations that can be covered is considerable due to the linear response of NMR signals, although metabolites occurring at extremely low concentrations may be difficult to detect. For the least abundant compounds, the highly sensitive mass spectrometry method may be advantageous although this technique requires more intricate sample preparation and quantification procedures than NMR spectroscopy. We present here an NMR protocol adjusted to rat brain analysis; however, the same protocol can be applied to other tissues with minor modifications.

The neurochemistry of mammalian brain is changed in many neurological and systemic diseases. Characteristic profiles of cerebral metabolites can be efficiently obtained based on crude extracts of brain tissue. To this end, high-resolution NMR spectroscopy is employed, enabling detailed quantitative analysis of metabolite concentrations (metabolomics).

Análisis de Metabolómica de cerebro de rata por Alta Resolución Nuclear Espectroscopía de Resonancia Magnética de Extractos de Tejidos

Studies of gene expression on the RNA and protein levels have long been used to explore biological processes underlying disease. More recently, genomics ...

Neurociencias

Shotgun Lipidomics of Rodent Tissues

Lipids play a vital role as essential components of all prokaryotic and eukaryotic cells. Constant technological improvements in mass spectrometry have made lipidomics a powerful analytical tool for monitoring tissue lipidome compositions in homeostatic as well as disease states. This paper presents a step-by-step protocol for a shotgun lipid analysis method that supports the simultaneous detection and quantification of a few hundred molecular lipid species in different tissue and biofluid samples at high throughput. This method leverages automated nano-flow direct injection of a total lipid extract spiked with labeled internal standards without chromatographic separation into a high-resolution mass spectrometry instrument. Starting from sub-microgram amounts of rodent tissue, the MS analysis takes 10 min per sample and covers up to 400 lipids from 14 lipid classes in mouse lung tissue. The method presented here is well suited for studying disease mechanisms and identifying and quantifying biomarkers that indicate early toxicity or beneficial effects within rodent tissues.

Shotgun mass spectrometry-based lipidomics delivers a sensitive quantitative snapshot of a broad spectrum of lipid classes simultaneously in a single measurement from various rodent tissues.

Lipidómica de escopeta de tejidos de roedores

Lipids play a vital role as essential components of all prokaryotic and eukaryotic cells. Constant technological improvements in mass spectrometry have ...

Concentration of Metabolites from Low-density Planktonic Communities for Environmental Metabolomics using Nuclear Magnetic Resonance Spectroscopy

Environmental metabolomics is an emerging field that is promoting new understanding in how organisms respond to and interact with the environment and each other at the biochemical level1. Nuclear magnetic resonance (NMR) spectroscopy is one of several technologies, including gas chromatography&#x2013;mass spectrometry (GC-MS), with considerable promise for such studies. Advantages of NMR are that it is suitable for untargeted analyses, provides structural information and spectra can be queried in quantitative and statistical manners against recently available databases of individual metabolite spectra2,3. In addition, NMR spectral data can be combined with data from other omics levels (e.g. transcriptomics, genomics) to provide a more comprehensive understanding of the physiological responses of taxa to each other and the environment4,5,6. However, NMR is less sensitive than other metabolomic techniques, making it difficult to apply to natural microbial systems where sample populations can be low-density and metabolite concentrations low compared to metabolites from well-defined and readily extractable sources such as whole tissues, biofluids or cell-cultures. Consequently, the few direct environmental metabolomic studies of microbes performed to date have been limited to culture-based or easily defined high-density ecosystems such as host-symbiont systems, constructed co-cultures or manipulations of the gut environment where stable isotope labeling can be additionally used to enhance NMR signals7,8,9,10,11,12. Methods that facilitate the concentration and collection of environmental metabolites at concentrations suitable for NMR are lacking. Since recent attention has been given to the environmental metabolomics of organisms within the aquatic environment, where much of the energy and material flow is mediated by the planktonic community13,14, we have developed a method for the concentration and extraction of whole-community metabolites from planktonic microbial systems by filtration. Commercially available hydrophilic poly-1,1-difluoroethene (PVDF) filters are specially treated to completely remove extractables, which can otherwise appear as contaminants in subsequent analyses. These treated filters are then used to filter environmental or experimental samples of interest. Filters containing the wet sample material are lyophilized and aqueous-soluble metabolites are extracted directly for conventional NMR spectroscopy using a standardized potassium phosphate extraction buffer2. Data derived from these methods can be analyzed statistically to identify meaningful patterns, or integrated with other omics levels for comprehensive understanding of community and ecosystem function.

A method for metabolite extraction from microbial planktonic communities is presented. Whole community sampling is achieved by filtration onto specially prepared filters. After lyophilization, aqueous-soluble metabolites are extracted. This approach allows for application of environmental metabolomics to trans-omics investigations of natural or experimental microbial communities.

La concentración de los metabolitos de las comunidades planctónicas de baja densidad para la metabolómica ambiental utilizando espectroscopia de Resonancia Magnética Nuclear

Environmental metabolomics is an emerging field that is promoting new understanding in how organisms respond to and interact with the environment and each ...

Lipidomics and Transcriptomics in Neurological Diseases

Lipids serve as the primary interface to brain insults or stimuli conducive to neurological diseases and are a reservoir for the synthesis of lipids with various signaling or ligand function that can underscore the onset and progression of diseases. Often changing at the presymptomatic level, lipids are an emerging source of drug targets and biomarkers. Many neurological diseases exhibit neuroinflammation, neurodegeneration, and neuronal excitability as common hallmarks, partly modulated by specific lipid signaling systems. The interdependence and interrelation of synthesis of various lipids prompts a multilipid, multienzyme, and multireceptor analysis in order to derive the commonalities and specificities of neurological contexts and to expedite the unravelling of mechanistic aspects of disease onset and progression. Ascribing lipid roles to distinct brain regions advances the determination of lipid molecular phenotype and morphology associated with a neurological disease.
Presented here is a modular protocol suitable for the analysis of membrane lipids and downstream lipid signals along with mRNA of enzymes and mediators underlying their functionality, extracted from discrete brain regions that are relevant for a particular neurological disease and/or condition. To ensure accurate comparative lipidomic profiling, the workflows and operating criteria were optimized and standardized for: i) brain sampling and dissection of regions of interest, ii) co-extraction of multiple lipid signals and membrane lipids, iii) dual lipid/mRNA extraction, iv) quantification by liquid chromatography multiple reaction monitoring (LC/MRM), and v) standard mRNA profiling. This workflow is amenable for the low tissue amounts obtained by sampling of the functionally discrete brain subregions (i.e. by brain punching), thus preventing bias in multimolecular analysis due to tissue heterogeneity and/or animal variability. To reveal peripheral consequences of neurological diseases and establish translational molecular readouts of neurological disease states, peripheral organ sampling, processing, and their subsequent lipidomic analysis, as well as plasma lipidomics, are also pursued and described. The protocol is demonstrated on an acute epilepsy mouse model.

This article presents a modular protocol for tissue lipidomics and transcriptomics, and plasma lipidomics in neurological disease mouse models targeting lipids underlying inflammation and neuronal activity, membrane lipids, downstream messengers, and mRNA-encoding enzymes/receptors underlying lipid function. Sampling, sample processing, extraction, and quantification procedures are outlined.

Lipidómica y Transcriptómica en Enfermedades Neurológicas

Lipids serve as the primary interface to brain insults or stimuli conducive to neurological diseases and are a reservoir for the synthesis of lipids with ...