Analysis Of Phospholipids Research Articles

A rapid method for the extraction and analysis of carotenoids and other hydrophobic substances suitable for systems biology studies with photosynthetic bacteria.

A simple, rapid, and inexpensive extraction method for carotenoids and other non-polar compounds present in phototrophic bacteria has been developed. The method, which has been extensively tested on the phototrophic purple non-sulphur bacterium Rhodospirillum rubrum, is suitable for extracting large numbers of samples, which is common in systems biology studies, and yields material suitable for subsequent analysis using HPLC and mass spectroscopy. The procedure is particularly suitable for carotenoids and other terpenoids, including quinones, bacteriochlorophyll a and bacteriopheophytin a, and is also useful for the analysis of polar phospholipids. The extraction procedure requires only a single step extraction with a hexane/methanol/water mixture, followed by HPLC using a Spherisorb C18 column, with a mobile phase consisting of acetone-water and a non-linear gradient of 50%–100% acetone. The method was employed for examining the carotenoid composition observed during microaerophilic growth of R. rubrum strains, and was able to determine 18 carotenoids, 4 isoprenoid-quinones, bacteriochlorophyll a and bacteriopheophytin a as well as four different phosphatidylglycerol species of different acyl chain compositions. The analytical procedure was used to examine the dynamics of carotenoid biosynthesis in the major and minor pathways operating simultaneously in a carotenoid biosynthesis mutant of R. rubrum.

Lipidomic study of olive fruit and oil using TiO2 nanoparticle based matrix solid-phase dispersion and MALDI-TOF/MS

A matrix solid-phase dispersion (MSPD) procedure, using titanium dioxide (TiO2) nanoparticle (NP) as sorbent, combined with a matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS) method was developed for selective extraction, fast visualization and qualitative analysis of phospholipids from olive fruit and oil samples. The protocol was optimized by testing different sorbents and washing and eluting solvents. The results indicated that clean MS spectrum could be obtained when TiO2 NP was utilized as MSPD sorbent, acidified water (pH5) was used for washing the matrix and enhancing the binding ability, and chloroform and methanol (1/2, v/v) were selected as eluting solvent. In addition, the efficiency of this method was compared with that of the classic Bligh & Dyer method which produced high abundance peaks of glycerides and suppressed the signals of phospholipids. Based on the optimum conditions, olive fruit and oil samples were successfully analyzed in both positive and negative ion modes. The whole method demonstrated to be promising for selective separation of phospholipids from non-phospholipids, and has great potential in fast lipidomic fingerprinting of olive fruits and oils for quality control.

Improved sensitivity of sedimentary phospholipid analysis resulting from a novel extract cleanup strategy

The detection of intact phospholipids (PLs) in sedimentary extracts using liquid chromatography–electrospray ionization-mass spectrometry (LC–ESI-MS) is commonly limited by ion suppression caused by complex matrices; the effect typically cannot be satisfactorily reduced using traditional column chromatographic cleanup procedures. We therefore implemented a cleanup strategy recently introduced for serum and plasma samples and adapted it for sedimentary lipid extracts. It involves selective retention of PLs on a zirconia-coated silica phase, available as a HybridSPE®-Phospholipid cartridge. Compared with conventional silica gel liquid chromatography, the HybridSPE-based protocol strongly enhances the detection of PLs using LC–ESI-MS as a result of more effective removal of complex environmental matrices, with negligible PL loss. The strength of the protocol was demonstrated by analysis of marine sediment samples from various depths and of different total organic carbon (TOC) content, for which we observed 1.2–2.7 times more intense signals from sedimentary PLs compared with the untreated reference. This new cleanup protocol significantly improves PL fingerprinting of microbial communities in sediments.

Lipid profiling of mammalian cells with in situ matrix-assisted laser desorption ionization-mass spectrometry

The analysis of cellular lipids and phospholipids has been of continuously increasing research interest due to the importance of these molecules in psychological process. In this work, a mass spectrometry-based method for direct, in situ analysis of lipids in cells was reported. Mammalian cells were directly cultured on ITO-coated glass and then analyzed by matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS). The matrix application process was achieved by electrospray coating, which produced a homogenous layer of matrix crystal on the sample. The detection results and reproducibility are satisfactory. With this method, a profile of abundant membrane lipids is generated, which is characteristic of cell type. In conclusion, this in situ MALDI-MS cellular lipid analysis method provides a platform for sensitive and robust molecular profiling of mammalian cells.

Serum Metabolome and Lipidome Changes in Adult Patients with Primary Dengue Infection

BackgroundDengue virus (DENV) is the most widespread arbovirus with an estimated 100 million infections occurring every year. Endemic in the tropical and subtropical areas of the world, dengue fever/dengue hemorrhagic fever (DF/DHF) is emerging as a major public health concern. The complex array of concurrent host physiologic changes has hampered a complete understanding of underlying molecular mechanisms of dengue pathogenesis.Methodology/Principle FindingsSystems level characterization of serum metabolome and lipidome of adult DF patients at early febrile, defervescence, and convalescent stages of DENV infection was performed using liquid chromatography- and gas chromatography-mass spectrometry. The tractability of following metabolite and lipid changes in a relatively large sample size (n = 44) across three prominent infection stages allowed the identification of critical physiologic changes that coincided with the different stages. Sixty differential metabolites were identified in our metabolomics analysis and the main metabolite classes were free fatty acids, acylcarnitines, phospholipids, and amino acids. Major perturbed metabolic pathways included fatty acid biosynthesis and β-oxidation, phospholipid catabolism, steroid hormone pathway, etc., suggesting the multifactorial nature of human host responses. Analysis of phospholipids and sphingolipids verified the temporal trends and revealed association with lymphocytes and platelets numbers. These metabolites were significantly perturbed during the early stages, and normalized to control levels at convalescent stage, suggesting their potential utility as prognostic markers.Conclusions/SignificanceDENV infection causes temporally distinct serum metabolome and lipidome changes, and many of the differential metabolites are involved in acute inflammatory responses. Our global analyses revealed early anti-inflammatory responses working in concert to modulate early pro-inflammatory processes, thus preventing the host from development of pathologies by excessive or prolonged inflammation. This study is the first example of how an omic- approach can divulge the extensive, concurrent, and dynamic host responses elicited by DENV and offers plausible physiological insights to why DF is self limiting.

High‐resolution imaging mass spectrometry reveals detailed spatial distribution of phosphatidylinositols in human breast cancer

High-resolution matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) is an emerging application for lipid research that provides a comprehensive and detailed spatial distribution of ionized molecules. Recent lipidomic approach has identified several phospholipids and phosphatidylinositols (PIs) are accumulated in breast cancer tissues and are therefore novel biomarker candidates. Because their distribution and significance remain unclear, we investigated the precise spatial distribution of PIs in human breast cancer tissues using high-resolution MALDI IMS. We evaluated tissues from nine human breast cancers and one normal mammary gland by negative ion MALDI IMS at a resolution of 10 μm. We detected 10 PIs with different fatty acid compositions, and their proportions were remarkably variable in the malignant epithelial regions. High-resolution imaging enabled us to discriminate cancer cell clusters from the adjacent stromal tissue within epithelial regions; moreover, this technique revealed that several PIs were specifically localized to cancer cell clusters. These PIs were heterogeneously distributed within cancer cell clusters, allowing us to identify two different populations of cancer cells that predominantly expressed either PI(18:0/18:1) or PI(18:0/20:3). Tracing the expression level of PIs during cancer cell progression suggested that the latter population is associated with the invasion. Our study documents a novel model for phospholipid analysis of breast cancer tissues by using high-resolution MALDI IMS and identifies candidate PIs that can describe a specific phenotype of cancer cells.

The Cause for Heart Disease and Strokes

There has been no solution to heart disease to date. I obtained discarded veins from bypass (CABG) surgeries and subjected them to phospholipid analysis. We also obtained arterial cells from human umbilical cords and cultured them with a decreasing concentration of either cholesterol or oxidized cholesterol. Patients undergoing CABG surgery and aging swine had significantly higher levels of sphingomyelin in their arterial cells than arterial cells from human umbilical cords. Oxidized low-density lipoprotein (OxLDL) and oxysterols further contribute to atherosclerosis by increasing the synthesis of thromboxane in platelets, a clotting factor. When we incubated arterial cells with cholesterol that had not been oxidized, even at twelve times the concentration of the oxidized cholesterols we used, there was no effect on sphingomyelin content, this shows that cholesterol itself is not the reason for heart disease, and has to be oxidized in order to cause harm. My study indicated that atherosclerosis is due to a diet that contains a high level of oxysterols. Normal levels of oxysterols in the plasma will not increase sphingomyelin levels. Removing oxidized fat from the diet should be considered as a therapeutic measure for atherosclerosis. Ancel Keys, who some consider the father of the cholesterol-heart disease hypothesis said in 1997: "There's no connection whatsoever between the cholesterol in food and cholesterol in the blood."

Headspace Volatile Oxylipins of Eastern Himalayan Moss Cyathophorella adiantum Extracted by Sample Enrichment Probe

Cyathophorella adiantum (Griff.) M. Fleisch. (Division-Bryophyta, Family-Daltoniaceae), an Eastern Himalayan moss was studied for the first time to identify the volatiles derived from cellular and membrane bound fatty acids. A high capacity sample enrichment probe (SEP) was used for extraction of headspace volatile (HSV) molecules followed by GC-MS analysis. Different short-chain oxylipins like alkenes, alkanes, saturated and unsaturated alcohols, saturated and unsaturated aldehydes, ketones were identified along with free and esterified fatty acids, cyclo compounds and some by-products of secondary metabolites. Fatty acid analysis of neutral lipids (NL) and phospholipids (PL) of this plant exhibits the predominance of C16 and C18 fatty acids. It also reveals some interesting information that might indicate the possible fatty acid precursors for volatile generation and their sources in this plant.

Role of PTEN in modulation of ADP-dependent signaling pathways in vascular endothelial cells

ADP plays critical signaling roles in the vascular endothelium. ADP receptors are targeted by several cardiovascular drugs, yet the intracellular pathways modulated by ADP are incompletely understood. These studies have identified important roles for the phosphatase PTEN in ADP-dependent modulation of the endothelial isoform of nitric oxide synthase (eNOS) as well as of lipid and protein kinase pathways in endothelial cells. We find that ADP-promoted eNOS activation as well as phosphorylation of p38 MAPK are enhanced by siRNA-mediated PTEN knockdown. However, the increase in ADP-dependent eNOS activation promoted by PTEN knockdown is abrogated by siRNA-mediated knockdown of p38 MAPK. These findings indicate that PTEN tonically suppresses both p38 phosphorylation as well as ADP-stimulated eNOS activity. A key enzymatic activity of PTEN is its role as a lipid phosphatase, catalyzing the dephosphorylation of phosphoinositol-3,4,5-trisphosphate (PIP3) to phosphoinositol-4,5-bisphosphate (PIP2). We performed biochemical analyses of cellular phospholipids in endothelial cells to show that siRNA-mediated PTEN knockdown leads to a marked increase in PIP3. Because these complex lipids activate the small GTPase Rac1, we explored the role of PTEN in ADP-modulated Rac1 activation. We used a FRET biosensor for Rac1 to show that ADP-dependent Rac1 activation is blocked by siRNA-mediated PTEN knockdown. We then exploited a FRET biosensor for PIP3 to show that the striking ADP-dependent increase in intracellular PIP3 is entirely blocked by PTEN knockdown. These studies identify a key role for PTEN in the modulation of lipid mediators involved in ADP receptor-regulated endothelial signaling pathways involving eNOS activation in vascular endothelial cells.

Surface modified BaTiO3 nanoparticles as the matrix for phospholipids and as extracting probes for LLME of hydrophobic proteins in Escherichia coli by MALDI–MS

In this paper, we report the dual function of 12-hydroxy octadecanoic acid (HOA)-modified barium titanate nanoparticles (BaTiO3 NPs) as the matrix for phospholipids (PLs) and as hydrophobic affinity probes for liquid–liquid microextraction (LLME) of hydrophobic proteins in Escherichia coli prior to their identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI–MS). FT-IR, SEM and TEM were used for the characterization of the HOA-modified BaTiO3 NPs. The surface modified BaTiO3 NPs acted as multifunctional probes (as extracting probes and as the matrix) for the analysis of PLs by MALDI–MS. Compared to 2,5-dihydroxybenzoic acid (2,5-DHB), the HOA-modified BaTiO3 NPs provided good PLs mass spectra with similar or improved signal-to-noise (S/N) ratio, which demonstrated the potentiality of HOA-modified BaTiO3 NPs as a PLs purpose matrix. This method was found to be linear in concentration ranges of 1.0–5.0μM and 1.0–10.0μM for L-A-phosphatidyl-l-serine (PS) and L-A-phsophatidic acid sodium (PA) with correlation coefficient (R2) values from 0.9905 to 0.9987. The detection limits were 0.20–0.35μM and 0.25–0.40μM for PS and PA, respectively. We also demonstrated the HOA-modified BaTiO3 NPs as extracting and as preconcentrating probes for the LLME of hydrophobic proteins in E. coli prior to their identification by MALDI–MS. Thus, the surface modified BaTiO3 NPs-assisted LLME coupled with MALDI–MS provides a simple methodology for the efficient extraction and determination of hydrophobic molecules in biological samples.

Mass spectrometry based phospholipidomics of mammalian thymus and leukemia patients: implication for function of iNKT cells

In previous studies phospholipids have been proved to be involved in biochemical, physiological, and pathological processes. As a special class of phospholipids, peroxisome-derived lipids (PDLs) have been proved to be potential ligands of invariant natural killer T (iNKT) cells in recent studies. Here, on the basis of phospholipidomics, we focused on the relative quantity of PDLs extracted from mammalian thymus or bone marrow using electrospray ionization mass spectrometry (MS). In phospholipid analysis, we identified 12 classes of phospholipids and accounted for their relative quantities by comparing their relative abundances in the MS(1) map. Our results show that PDLs are present in mammalian thymus as well as mouse spleen and liver. Interestingly, the relative quantity of PDLs extracted from human acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) bone marrows is higher than that extracted from bone marrow of healthy donors. Our results may help to explain the close correlation between PDLs and iNKT cell function in thymus, spleen, liver, and especially in leukemia patients. We think that our phospholipidomics work may reveal a function of iNKT cells.

Phospholipid analyses by MALDI-TOF/TOF mass spectrometry using 1,5-diaminonaphthalene as matrix

Phospholipids (PLs) are the major components of cellular membranes and play important biological roles. To effectively identify PL species and avoid chemical background interferences, 1,5-diaminonaphthalene (DAN) was introduced as a matrix in this study. A systematic evaluation of three established matrix substances, especially 2,5-dihydroxybenzoic acid (DHB) and 9-aminoacridine hemihydrate (9AA) as reference compounds, for phospholipid (PL) analysis was performed. Spectra of all analytes (phosphocholine (PC) in positive ion mode, the rest in negative ion mode) using DAN as the matrix showed only protonated/deprotonated analyte signals. Moreover, the spectra were totally devoid of any matrix related signals. In addition, ionization efficiency of PLs using DAN as matrix was evaluated, and improved signal intensities of analytes with low laser energy were produced, making DAN a versatile and sensitive reagent for PL analysis. DAN was also successfully applied to the PLs identification of Geobacillus stearothermophilus, in which phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) were found to be the major classes. All the results indicate that DAN is a promising matrix for high-speed and effective lipidomics study by MALDI-TOF/TOF-MS.

Simple and Efficient Profiling of Phospholipids in Phospholipase D‐modified Soy Lecithin by HPLC with Charged Aerosol Detection

AbstractDietary phosphatidylinositol (PI) can be synthesized via phospholipase D (PLD)‐catalyzed transphosphatidylation of phosphatidylcholine (PC), abundant in soy lecithin, with myo‐inositol. However, a generated mixture of phospholipid (PL) classes poses a challenge for analysis. Our current work on Streptomyces PLD engineering requires a robust analytical method for profiling of PI and related PLs derived from the transphosphatidylation reactions. Therefore, we optimized an HPLC‐based method with charged aerosol detector (CAD) for PL quantification. PLs were separated on a normal phase silica column by a gradient elution system using two solvents containing chloroform/methanol/1 M formic acid–triethylamine buffer in different ratios. Retention times of the PL standards and LC–MS under identical conditions were used to identity PL classes. PL standards gave linear response in 100‐ and 10‐fold (lyso‐PI) concentration range. The method provided a simple, sensitive, repeatable, and precise analysis of PI, PC, phosphatidylethanolamine, phosphatidic acid, and lyso forms of PC and PI. Compared to the similar existing method, introduction of CAD provided a three‐ to fivefold decrease at the lower end and a two‐ to fivefold increase at the upper end of the dynamic range. High precision, high sensitivity, and low limits of detection and quantification further underline the benefits of CAD in PL analysis.

Application of Choline and Glycine Betaine Alters Levels of Total Phosholipids in Olea europaea L. Related to Cold Hardiness

Many plants accumulate cryoprotectant compounds in response to low temperatures such as Glycine betaine (GB). GB is synthesized by a simple two‐step pathway from the primary metabolite choline (Cho). Exogenous applications can improve the growth and survival of numerous species under several abiotic stresses. Although GB and Cho are studied in various plants, only a small number of studies investigated their roles during abiotic stress in the Olea europaea L. In addition, no study has yet investigated effects of GB and Cho application on phospholipid levels. Hence, the aim of the present study was to elucidate whether accumulation and the alterations in the phospholipids were related to GB and Cho applications in cold‐tolerant (Domat) and cold‐sensitive (Manzanilla) cultivars in non‐acclimated stages. For this purpose, 50 mM of GB and Cho solutions were applied as a foliar spray on leaves of two year‐old olive genotypes for three weeks. Leaf samples were collected for evaluations of freezing tolerance and phospholipid analysis. Results revealed that total phospolipids were greater in cv. Domat than those in cv. Manzanilla parallelling to their cold hardiness. In addition, total phospholipid content was greater in GB‐applied samples than that in Cho‐applied samples. Consequently, Cho and GB applications may protect olive leaves by altering cellular phospholipid content.

Abstract P038: Associations of Plasma Phospholipid and Dietary Alpha Linolenic Acid with Mortality, Coronary Heart Disease and Stroke in Older Adults: The Cardiovascular Health Study

Objective: To examine the association of α-linolenic acid (ALA 18:3n-3), an essential n-3 fatty acid derived from plants and vegetable oils, with mortality, coronary heart disease, and stroke among older adults. Due to the low correlation between dietary and circulating ALA that may reflect differences in diet and metabolism, we evaluated plasma phospholipid ALA and dietary ALA separately. Methods: The study population included participants from the Cardiovascular Health Study, a community-based longitudinal cohort of adults aged 65 or older, free of prevalent coronary heart disease and stroke. A total of 2,709 participants comprised the plasma phospholipid analysis group and 4,214 participants comprised the dietary analysis group. Plasma phospholipid ALA, an objective measure of circulating levels of ALA over the past 4-8 weeks, was measured using stored samples from 1992-1993. Dietary fatty acid intake was ascertained using food frequency questionnaires administered in 1989 and 1996. ALA was expressed as percent of total fatty acids and percent of total dietary fat for the plasma phospholipid and dietary analyses, respectively. Cox regression was used to assess the associations of plasma phospholipid and dietary ALA with mortality, and incident coronary heart disease or stroke. Results: Dietary ALA and plasma phospholipid ALA were modestly correlated (r=0.18). We found no statistically significant associations of plasma phospholipid ALA with mortality, incident CHD or stroke (table). After adjustment for potential confounders, dietary intake of ALA was associated with a lower risk of total and non-CVD mortality. We found no statistically significant associations of dietary ALA with CVD mortality, incident CHD or stroke (table). Conclusions: Results from this prospective cohort study of older adults suggest that dietary, but not plasma phospholipid ALA, is associated with a lower risk of total and non-CVD mortality in older adults.

Egg Consumption Modulates HDL Lipid Composition and Increases the Cholesterol‐Accepting Capacity of Serum in Metabolic Syndrome

We recently demonstrated that daily whole egg consumption during moderate carbohydrate restriction leads to greater increases in plasma HDL-cholesterol (HDL-C) and improvements in HDL profiles in metabolic syndrome (MetS) when compared to intake of a yolk-free egg substitute. We further investigated the effects of this intervention on HDL composition and function, hypothesizing that the phospholipid species present in egg yolk modulate HDL lipid composition to increase the cholesterol-accepting capacity of subject serum. Men and women classified with MetS were randomly assigned to consume either three whole eggs (EGG, n=20) per day or the equivalent amount of egg substitute (SUB, n=17) throughout a 12-week moderate carbohydrate-restricted (25-30% of energy) diet. Relative to other HDL lipids, HDL-cholesteryl ester content increased in all subjects, with greater increases in the SUB group. Further, HDL-triacylglycerol content was reduced in EGG group subjects with normal baseline plasma HDL-C, resulting in increases in HDL-CE/TAG ratios in both groups. Phospholipid analysis by mass spectrometry revealed that HDL became enriched in phosphatidylethanolamine in the EGG group, and that EGG group HDL better reflected sphingomyelin species present in the whole egg product at week 12 compared to baseline. Further, macrophage cholesterol efflux to EGG subject serum increased from baseline to week 12, whereas no changes were observed in the SUB group. Together, these findings suggest that daily egg consumption promotes favorable shifts in HDL lipid composition and function beyond increasing plasma HDL-C in MetS.

Changes in Membrane Fatty Acid Composition of Pseudomonas aeruginosa in Response to UV-C Radiations

The changes in lipid composition enable the micro-organisms to maintain membrane functions in the face of environmental fluctuations. The relationship between membrane fatty acid composition and UV-C stress was determined for mid-exponential phase and stationary phase Pseudomonas aeruginosa. The total lipids were obtained by dichloromethane/methanol (3:1) and were quantified by GC. The TLC analysis of phospholipids showed the presence of three major fractions phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin. Significant modifications, as manifested by an increase of UFA, were obtained. Interestingly, this microorganism showed a remarkable capacity for recovery from the stressful effects of UV-C.

Enhanced activities of reproductive system in male rat treated with male silkworm pupae extract

AbstractA male silkworm pupae extract with herbal mixtures such as Rubus coreanus Miquel, Chinese matrimony vine Acanthopanax senticosus and tocopherol can be effectively used to recover or boost stamina. In this study, the effect of the male silkworm pupae extract on the reproductive system of Sprague–Dawley male rats was investigated. No clinical symptoms, and no dying or dead animals were found among experimental male silkworm larvae extract, male silkworm pupae extract and control rat groups during the study. No significant differences were found in body weights, feed or water consumption, or macroscopic examination among the three groups. No lesion was found upon necropsy. However, sperm in the group treated with male silkworm pupae extract were significantly more active than sperm in the control group. Sperm counts in both male groups treated with male silkworm larvae extract and male silkworm pupae extract were significantly higher than sperm counts in the control group. Analysis of phospholipid–hydroperoxide glutathione peroxidase (PHGPx) gene expression showed that the male silkworm pupae extract increased expression in testes by 26.7%. This study shows that the male silkworm pupae extract has potential to be used to enhance the function of the human reproductive system.

Isolation of Sarcolemmal Plasma Membranes by Mechanically Skinning Rat Skeletal Muscle Fibers for Phospholipid Analysis

Membrane phospholipid (PL) composition has been shown to affect cellular function by altering membrane physical structure. The sarcolemma plasma membrane (SLpm) is integral to skeletal muscle function and health. Previous studies assessing SLpm PL composition have demonstrated contamination from transverse (t)-tubule, sarcoplasmic reticulum, and nuclear membranes. This study assessed the possibility of isolating SL by mechanically skinning skeletal muscle fiber segments for the analysis of SLpm PL composition. Mechanically skinned SLpm from rat extensor digitorum longus (EDL) muscle fibers underwent Western blot analysis to assess contamination from t-tubule, sarcoplasmic reticulum, nuclear and mitochondrial membranes. The results indicate that isolated SLpm had minimal nuclear and mitochondrial membrane contamination and was void of contamination from sarcoplasmic reticulum and t-tubule membranes. After performing both high-performance thin layer chromatography and gas chromatography, we found that the SLpm obtained by mechanical skinning had higher sphingomyelin and total fatty acid saturation and lower phosphatidylcholine when compared to previous literature. Thus, by avoiding the use of various chemical treatments and membrane fractionation, we present data that may truly represent the SLpm and future studies can use this technique to assess potential changes under various perturbations and disease conditions such as insulin resistance and muscular dystrophy.

Cancer biomarkers and mass spectrometry-based analyses of phospholipids in body fluids

The lipid profiles of body fluids reflect the general condition of the whole organism and can indicate the existence of certain diseases such as cancer. Qualitative and quantitative assessment of lipids in blood and other body fluids could reveal novel biomarkers for early detection and prognosis of cancer; in addition, it may be useful in monitoring the efficacy and toxicity of anticancer treatment. Consequently, lipidomics is an emerging approach in cancer research. Phospholipids make up an important lipid class, which is particularly suitable for analyses by mass spectrometry. Mass spectrometry methods involving ‘soft’ ionization techniques, such as electrospray ionization and matrix-assisted laser desorption ionization, which are well established in the proteomics field, have also been implemented in analyses of lipids. This review focuses on the application of electrospray ionization and matrix-assisted laser desorption ionization mass spectrometry in the characterization of structure and composition of phospholipids present in biofluids, and their importance for cancer-related problems.