Neutral Glycolipids Research Articles

Lipid discovery enabled by sequence statistics and machine learning.

Bacterial membranes are complex and dynamic, arising from an array of evolutionary pressures. One enzyme that alters membrane compositions through covalent lipid modification is MprF. We recently identified that Streptococcus agalactiae MprF synthesizes lysyl-phosphatidylglycerol (Lys-PG) from anionic PG, and a novel cationic lipid, lysyl-glucosyl-diacylglycerol (Lys-Glc-DAG), from neutral glycolipid Glc-DAG. This unexpected result prompted us to investigate whether Lys-Glc-DAG occurs in other MprF-containing bacteria, and whether other novel MprF products exist. Here, we studied protein sequence features determining MprF substrate specificity. First, pairwise analyses identified several streptococ-cal MprFs synthesizing Lys-Glc-DAG. Second, a restricted Boltzmann machine-guided approach led us to discover an entirely new substrate for MprF in Enterococcus , diglucosyl-diacylglycerol (Glc 2 -DAG), and an expanded set of organisms that modify glycolipid substrates using MprF. Overall, we combined the wealth of available sequence data with machine learning to model evolutionary constraints on MprF sequences across the bacterial domain, thereby identifying a novel cationic lipid.

Metabolic insights into high-altitude adaptation of Himalayan ‘Horsetails’ [Equisetum diffusum D. Don] with special reference to the fatty acid dynamicity

Equisetum diffusum D. Don, a perennial herb of Equisetaceae, is considered as native to the Himalayan mountain range. This plant has prolific distribution along different altitudes of Eastern Himalayan region. Generally, mountain flora, like E. diffusum, experience a combination of contrasting abiotic stresses and may represent a unique natural model for investigating physiological resilience to address climate change. So, the present study has been framed to compare the metabolic responses in E. diffusum growing at different elevation belts with an aim to understand the underlying basis for their high-altitude adjustment ability. The biochemical profiles of this plant, collected from three different altitudinal transects of Darjeeling hills, were compared. The fatty acid profiles of neutral lipids, membrane phospholipids and glycolipids demonstrated palmitic acid and oleic acid as the predominant fatty acids. The major outcome was the substantial increase of polyunsaturated fatty acids (PUFAs) and unsaturation index in glycolipids of the samples collected from higher altitudes. Major proportion of changes in PUFA content was contributed by arachidonic acid. Therefore, the plants homeostatically control the membrane fluidity by enhancing the unsaturation of glycolipid fatty acids. Moreover, significantly higher antioxidant enzyme activities in higher altitude samples reflect the involvement of these enzymes in coping with the oxidative stress condition and membrane damage. The stress responsive effects may be further augmented by enhanced content of secondary metabolites. Therefore, a combination of biochemical responses along with the changes in membrane plasticity can be predicted as the metabolic adjustment strategies for high-altitude adaptation of E. diffusum.

Characterization of Neutral Lipids of the Oleaginous Alga Micractinum inermum.

An oleaginous microalga Micractinum inermum isolated from Mariana Lake, AB, Canada was cultured in a 1000 L photobioreactor with an f/2 medium to study its lipid content and neutral lipid profile. Algal biomass was collected at the stationary phase contained a significant amount of lipids (44.2%), as determined by Folch's method. The lipid was fractionated into neutral lipid, glycolipid and phospholipid fractions. The neutral lipid constitutes almost 77.3% of the total lipid species and is mainly composed of triacylglycerols (TAGs) determined by a proton NMR study. UHPLC-HRMS analysis allows us for the first time to identify 81 TAGs in the neutral lipid fraction of M. inermum. The fatty acid acyl side chains were identified based on fragment ions observed in MSMS analysis. TAGs with fatty acid acyl chains 18:1/18:1/18:1, 18:1/18:1/16:0, 18:2/18:1/16:0, and 18:2/18:2/18:0 were the major ones among the identified TAGs. Fatty acid analysis further supports the fact that oleic acid was the major fatty acid present in the neutral lipid fraction of M. inermum constituting 41.7%, followed by linoleic acid at 21.5%, and palmitic acid at 21.2%. The saturated and monounsaturated fatty acids were 67.8% or higher in the lipid fraction. Long-chain fatty acids were only present in a minor quantity. The results clearly demonstrate that M. inermum is an excellent source for TAGs.

Immune Enhancement Effects of Neutral Lipids, Glycolipids, Phospholipids from Halocynthia aurantium Tunic on RAW264.7 Macrophages.

Fractionated lipids of Halocynthia aurantium (Pyuridae) have been demonstrated to possess anti-inflammatory properties. However, their modulatory properties have not been reported yet. Thus, the objective of this study was to determine immune enhancing effects of fractionated lipids from H. aurantium tunic on macrophage cells. The tunic of H. aurantium was used to isolate total lipids, which were then subsequently separated into neutral lipids, glycolipids, and phospholipids. RAW264.7 cells were stimulated with different concentrations (0.5, 1.0, 2.0, and 4.0%) of each fractionated lipid. Cytotoxicity, production of NO, expression levels of immune-associated genes, and signaling pathways were then determined. Neutral lipids and glycolipids significantly stimulated NO and PGE2 production and expression levels of IL-1β, IL-6, TNF-α, and COX-2 in a dose-dependent manner, while phospholipids ineffectively induced NO production and mRNA expression. Furthermore, it was found that both neutral lipids and glycolipids increased NF-κB p-65, p38, ERK1/2, and JNK phosphorylation, suggesting that these lipids might enhance immunity by activating NF-κB and MAPK signaling pathways. In addition, H. aurantium lipids-induced TNF-α expression was decreased by blocking MAPK or NF-κB signaling pathways. Phagocytic activity of RAW 264.7 cells was also significantly enhanced by neutral lipids and glycolipids. These results suggest that neutral lipids and glycolipids from H. aurantium tunic have potential as immune-enhancing materials.

Beyond PLFA: Concurrent extraction of neutral and glycolipid fatty acids provides new insights into soil microbial communities

The analysis of phospholipid fatty acids (PLFAs) is one of the most common methods used to quantify the abundance, and analyse the community structure, of soil microbes. The PLFA extraction method can yield two additional lipid fractions—neutral lipids and glycolipids—which potentially hold additional, valuable information on soil microbial communities. Yet its quantitative sensitivity on complete neutral lipid (NLFA) and glycolipid fatty acid (GLFA) profiles has never been validated. In this study we tested (i) if the high-throughput PLFA method can be expanded to concurrently extract complete NLFA and GLFA profiles, as well as sterols, (ii) whether taxonomic specificities of signature fatty acids are retained across the three lipid fractions in pure culture strains, and (iii) whether NLFAs and GLFAs allow soil-specific fingerprinting to the same extent as PLFA analysis. By adjusting the polarity of chloroform with 2% ethanol for solid phase extraction, pure lipid standards were fully fractionated into neutral lipids, glycolipids, and phospholipids. Sterols eluted in the neutral lipid fraction, and a betaine lipid co-eluted with phospholipids. We found consistent taxonomic specificities of fatty acid markers across the three lipid fractions by analysing pure culture extracts representative of soil microbes. Fatty acid profiles from soil extracts, however, showed stronger differences between PLFAs, NLFAs, and GLFAs than between soil types. This indicates that PLFAs and NLFAs signify different community properties (biomass vs. carbon storage, putatively), and that GLFAs are sensitive markers for community traits which behave differently than PLFAs. Although we consistently found high abundances of characteristic sterols in fungal extracts, the PLFA extraction method only yielded miniscule amounts of ergosterol from soil extracts. We argue that concomitant measurement of fatty acid profiles from all three lipid fractions is a low-effort and potentially information-rich addition to the PLFA method, and discuss its applicability for soil microbial community analyses.

Auxin supplementation under nitrogen limitation enhanced oleic acid and MUFA content in Eustigmatos calaminaris biomass with potential for biodiesel production

Due to their lipid accumulation potential, microalgae are widely studied in terms of their use in the production of biodiesel. The present study was focused on determination of changes in the biomass production, biochemical composition, accumulation and distribution of fatty acids in neutral lipids, glycolipids, phospholipids and biodiesel properties of soil microalga Eustigmatos calaminaris in response to various levels of nitrogen stress and indole-3-acetic acid supplementation. The highest growth rate, the highest lipid content and daily lipid productivity were noted at the nitrogen limitation up to 25% with IAA supplementation. The increase in NL was associated with nutrient stress. An increase in the level of GL and PL were recorded upon the reduction of the nitrogen content (25% N) and the addition of IAA. The gas chromatography/mass spectrometry analysis demonstrated that C16:0, C16:1, and C18:1 were the main fatty acids in E. calaminaris lipids. As shown by the lipidomic analysis, the IAA supplementation in the nitrogen limitation variants enhanced the content of TAGs in C18:1 and monounsaturated fatty acids. The current findings indicated a potential strategy to improve the fatty acid profile in neutral lipids and high potential of E. calaminaris for biodiesel applications.

A pilot study assessing sphingolipids and glycolipids dysmetabolism in idiopathic normal pressure hydrocephalus

Idiopathic normal pressure hydrocephalus usually exhibits triad of symptoms including gait disturbance, urinary incontinence, and dementia with ventriculomegaly. Currently, its pathogenesis remains to be fully elucidated.To provide a better understanding of this order, we examined whether dysmetabolism of sphingolipids as major lipid components in the brain present in cerebrospinal fluid (CSF) of the patients. Here, we measured various sphingolipidsincluding ceramide and sphingomyelin and glycolipids by electrospray ionization-tandem mass spectrometry in the cerebrospinal fluid of 19 consecutive idiopathic normal pressure hydrocephalus patients, 49 Parkinson's disease patients, and 17 neurologically normal controls.The data showed that there was a significant and specific reduction of all galactosylceramide subspecies levels in idiopathic normal pressure hydrocephalus patients compared with other groups, whereas ceramide and sphingomyelin levels as well as other neutral glycolipids such as glucosylceramide and lactosylceramide were similar in both disease states. Multiple regression analysis of sex and age did not show any correlation with galactosylceramide levels. We also examined whether MMSE scores are correlated with sphingolipid levels in iNPH patients. A specific subspecies of sphingomyelin (d18:1/18:0) only exhibited a statistically significant negative correlation (p = 0.0473, R = −0.4604) with MMSE scores but no other sphingolipids in iNPH patients. These data strongly suggest that myelin-rich galactosylceramide metabolism is severely impaired in idiopathic normal pressure hydrocephalus patients and might serve as the basis of biomarker for this disorder.

Langmuir monolayers as models of the lipid matrix of cyanobacterial thylakoid membranes

Cyanobacteria are omnipresent photosynthetic microorganisms that are crucial for the proper functioning of multiple environmental niches. Recently, these organisms have found various applications in soil remediation, waste utilization, and the production of biodegradable polymers. A significant volume of the cyanobacterial cell is occupied by thylakoid membranes, where the photosynthesis process is localized. These membranes are inhomogeneous and highly compartmentalized; however, the stimuli and forces leading to such a high degree of self-organization are not entirely understood. In our study, we apply Langmuir monolayers formed by the main lipids of cyanobacterial membranes: monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulfoquinovosyldiacylglycerol (SQDG), and phosphatidylglycerol (PG), as versatile models of thylakoid membranes. Special attention was paid to the binary system formed by the two neutral glycolipids MGDG and DGDG, as these two substances are most abundant in the membrane. Then the effects implied by the incorporation of anionic lipids were investigated. The morphology of the monolayers was studied by Brewster angle microscopy, while the ordering of the monolayer-forming molecules on the molecular scale was investigated with the Grazing incidence X-ray diffraction technique. It was proved that the inhomogeneous structure of cyanobacterial membrane is an intrinsic property of the applied structural lipids. It was also proved that the increase in anionic lipid content, frequently applied by cyanobacteria as a response to unfavorable environmental conditions, leads to significant changes in the morphology of the model membranes.

Anti-inflammatory properties of neutral lipids, glycolipids, and phospholipids isolated from Ammodytes personatus eggs in LPS-stimulated RAW264.7 cells

In the present study, total lipids were extracted from Ammodytes personatus eggs and separated into neutral lipids, glycolipids, and phospholipids. The anti-inflammatory activity of the neutral lipids, glycolipids, and phospholipids was investigated in macrophages, as well as the fatty acid profiles of the lipids. Palmitic acid, oleic acid, docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) were the primary fatty acids in the three fractionated lipids. Among the lipids, the phospholipids contained the highest concentration of polyunsaturated fatty acids (PUFAs), particularly DHA and EPA (31.89 and 16.93% of the total fatty acids, respectively). The anti-inflammatory effects of the three lipids isolated from A. personatus eggs were analyzed in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The three lipids significantly reduced nitric oxide (NO) production and the mRNA expression of immune-associated genes in a dose-dependent manner. All lipids down-regulated the protein expression of phosphorylated NF-κB-p65 and MAPK (p38, JNK, and ERK1/2) signaling pathways, suggesting that they could inhibit cell signaling pathways by activating NF-κB and MAPK. The expression of CD40 and CD86 in LPS-stimulated RAW264.7 cells was also significantly decreased by A. personatus lipids. Consequently, the neutral lipids, glycolipids, and phospholipids from A. personatus eggs could serve as anti-inflammatory agents.

Anti-inflammatory effects of neutral lipids, glycolipids, phospholipids from Halocynthia aurantium tunic by suppressing the activation of NF-κB and MAPKs in LPS-stimulated RAW264.7 macrophages.

Halocynthia aurantium is a marine organism that has been considered a promising source for bio-functional materials. Total lipids were extracted from H. aurantium tunic, and then they were separated into neutral lipids, glycolipids, and phospholipids. In the present study, fatty acid profiles of three lipids and their anti-inflammatory effects in RAW264.7 cells were investigated. Among the lipid classes, phospholipids showed the diversity of fatty acid constituents, compared with the glycolipids and neutral lipids. Three lipids contain different contents of fatty acids depending on the kinds of lipids. The most contents were saturated fatty acids (SFAs, 53-69% of the fatty acids) and monounsaturated fatty acids (MUFAs, 15-17% of fatty acids) and polyunsaturated fatty acids (PUFAs, 14-32% of fatty acids) are followed. H. aurantium lipids not only dose-dependently inhibited nitric oxide production but also reduced the expression of inflammatory cytokine genes such as TNF-α, IL-1β, and IL-6 in LPS-stimulated macrophages. It was also demonstrated that the expression of COX-2 was dose-dependently suppressed. Moreover, H. aurantium lipids decreased phosphorylation of NF-κB p-65, p38, ERK1/2, and JNK, suggesting that three lipids from H. aurantium tunic provide anti-inflammatory effects through NF-κB and MAPK signaling. These results indicate that H. aurantium is a potential source for anti-inflammation.

Response Surface Optimization of Enzyme Pretreatment Improves Yield of Ethanol‐Extracted Lipids from Nannochloropsis oceanica

AbstractNannochloropsis oceanica are marine microalgae that are rich in eicosapentaenoic acid (EPA); in the future, they may become one of the most effective sources of EPA. The cell walls of N. oceanica contain a three‐layered dense structure called algaenan, which hinders the extraction of intracellular lipids. Here, the main variables for the enzyme pretreatment of N. oceanica are optimized using response surface methodology. Under the optimal variables for enzyme pretreatment, the lipid yield and EPA content are increased to 26.9% and 20.7 g/100 g, respectively. Furthermore, lipidomics analysis is carried out utilizing ultra‐high performance liquid‐quadrupole‐time‐of‐flight mass spectrometry to identify the obtained lipids. After enzyme treatment, the betaine lipids (BL) content significantly increases, probably due to laccase and cellulase promoting the release of BL from membrane structure. In comparison, the hydrolysis of neutral lipids, glycolipids, and phospholipids during the enzyme treatment reduces their respective contents. The results of this study suggest that using compound enzymes to pretreat N. oceanica can effectively increase lipids extraction yields by ethanol and improve the EPA contents in lipids.Practical applications: This study indicates that enzyme pretreatment can promote the extraction of lipids, especially lipids with EPA, from N. oceanica or other marine microalgae.

Identification of a novel cationic glycolipid in Streptococcus agalactiae that contributes to brain entry and meningitis.

Bacterial membrane lipids are critical for membrane bilayer formation, cell division, protein localization, stress responses, and pathogenesis. Despite their critical roles, membrane lipids have not been fully elucidated for many pathogens. Here, we report the discovery of a novel cationic glycolipid, lysyl-glucosyl-diacylglycerol (Lys-Glc-DAG), which is synthesized in high abundance by the bacterium Streptococcus agalactiae (Group B Streptococcus, GBS). To our knowledge, Lys-Glc-DAG is more positively charged than any other known lipids. Lys-Glc-DAG carries 2 positive net charges per molecule, distinct from the widely described lysylated phospholipid lysyl-phosphatidylglycerol (Lys-PG) that carries one positive net charge due to the presence of a negatively charged phosphate moiety. We use normal phase liquid chromatography (NPLC) coupled with electrospray ionization (ESI) high-resolution tandem mass spectrometry (HRMS/MS) and genetic approaches to determine that Lys-Glc-DAG is synthesized by the enzyme MprF in GBS, which covalently modifies the neutral glycolipid Glc-DAG with the cationic amino acid lysine. GBS is a leading cause of neonatal meningitis, which requires traversal of the endothelial blood–brain barrier (BBB). We demonstrate that GBS strains lacking mprF exhibit a significant decrease in the ability to invade BBB endothelial cells. Further, mice challenged with a GBSΔmprF mutant developed bacteremia comparably to wild-type (WT) infected mice yet had less recovered bacteria from brain tissue and a lower incidence of meningitis. Thus, our data suggest that Lys-Glc-DAG may contribute to bacterial uptake into host cells and disease progression. Importantly, our discovery provides a platform for further study of cationic lipids at the host–pathogen interface.

Tilapia nilotica Head Lipids Improved Bone Loss by Regulating Inflammation and Serum Metabolism Through Gut Microbiota in Ovariectomized Rats.

Osteoporosis is a global health problem, and it is of great significance to replace the drugs with natural functional factors. In this study, we investigated the antiosteoporotic activity of lipids prepared from Tilapia nilotica fish head lipids (THLs) in the ovariectomized osteoporosis rats. THLs are composed of neutral lipids (NL, 77.84%), phospholipids (PL, 11.86%), and glycolipids (GL, 6.47%). There were apparent differences in the fatty acid composition of disparate components, and PL contains the most abundant Ω-3 polyunsaturated fatty acids. The results proved that THLs could improve bone microstructure, increase bone mineral density, and decrease bone resorption. To illustrate the antiosteoporotic mechanism, we analyzed the changes in gut microbial communities, proinflammation factors, serum metabolites, and metabolic pathways. Further study on gut microbiota showed that THLs significantly decreased the content of Alistipes in the gut and dramatically increased the beneficial bacteria such as Oscillospira, Roseburia, and Dubosiella. Meanwhile, proinflammation factors of serum in OVX rats decreased significantly, and metabolites were changed. Therefore, we speculated that THLs improved bone loss through reducing inflammation and changing the metabolites and metabolic pathways such as arachidonic acid metabolism and primary bile acid metabolism, etc., by altering gut microbiota. The results indicated that THLs could be a functional factor with antiosteoporotic activity.

Перспективы разработки хлебобулочных изделий, обогащённых липидными фракциями морских водорослей

The paper presents the results of studying the lipid composition of bakery products (HBI) with the addition of new ingredients to its formulation - water-ethanol extracts, four types of seaweed: green algae – Ulva lactuca; two types of brown algae – Sargassum pallidum and Japanese saccharin; red algae – Anfeltia tobuchinskaya, containing the main lipids – neutral lipids and glycolipids. The data obtained showed a change in the lipid composition of the developed bread. A statistically significant increase in all fractions of neutral lipids was registered in the developed CBI, a decrease in the amount of cholesterol and its cholesterol esters, compared with those in control samples. An increase in the amount of phosphatidylcholine (lecithin) in bread with the addition of kelp and anfeltia extracts was noted; a significant increase in phosphatidylethanolamine in bread with the introduction of all algal extracts. The revealed facts demonstrate the stability of lipid fractions in the composition of CBI with the addition of algae extracts and are positive in terms of giving them preventive properties. Particularly indicative is the appearance of the phosphatidylglycerol fraction in bread, which is the basis for the synthesis of other phospholipid compounds from it, which are essential substances that enter the human body exclusively through food, reducing the risks and consequences of adverse environmental factors affecting the body.

Species-specific accumulation of ceramides in cerebrospinal fluid from encephalomyeloradiculoneurpathy patients associated with peripheral complement activation: A pilot study

Glycolipids are now known to be rapidly converted to mediators for inflammatory reactions or to signaling molecules that control inflammatory events in the nervous system. The present study aimed to explore whether disturbed glycolipids metabolism in the nervous system is present in patients with a neuroinflammatory disorder, encephalo-myelo-radiculo-neuropathy (EMRN), because most EMRN patients have been reported to exhibit autoantibodies against neutral glycolipids. Although molecular pathogenesis of this disorder remains unknown, we tried to search the immunochemical abnormalities in this disorder. ELISA for activated peripheral C5 complement and mass spectrometry analysis of cerebrospinal fluid clearly disclosed a significant upregulation of active C5 complement, C5a levels in sera as well as a significant accumulation of species-specific ceramides but not sphingomyelin in cerebrospinal fluid from EMRN patients. Furthermore, we confirmed the occurrence of anti-neutral glycolipids antibodies in all EMRN patients.Thus, the present study might indicate the pathophysiology of this disorder is the dysregulation of glycolipids metabolism and abnormal production of autoantibodies against neutral glycolipids resulting in the abnormal complement activation, although molecular basis for these sphingolipids dysregulation and the occurrence of autoantibodies against glycolipids remains to be elucidated at present. The present study implicates a new therapeutic strategy employing anti-ceramide and/or anti-complement therapy for this disorder.

Enzymatic production of isopropyl and 2-ethylhexyl esters using γ-linolenic acid rich fungal oil produced from spent sulphite liquor

The enzymatic production of isopropyl and 2-ethylhexyl esters was investigated using fungal oil produced via fermentation of nanofiltrated spent sulphite liquor (SSL). Screening of five oleaginous fungi showed that Cunninghmamella echinulata could accumulate lipids with 12 % (w/w) γ-linolenic acid content in shake flask cultures. Ester formation by the commercial lipase Novozym 435 was favored when transesterifications of fungal oil with isopropyl and 2-ethylhexyl alcohols were performed at 60 °C, 1:3 microbial oil to alcohol molar ratio and 10 % biocatalyst concentration. Transesterifications of individual neutral lipids (NL), glycolipids and sphingolipids (GL + SL) and phospholipids (PL), with isopropanol and 2-ethyl-hexanol showed that the presence of GL + SL and PL in fungal oil hindered ester production. Transesterification of the NL fraction alone with isopropanol and 2-ethylhexanol led to the highest conversion yield of 80.2 % and 73.8 %, respectively. Conversion yields to isopropyl and 2-ethylhexyl esters reached up to 90 % and 80 % (w/w), respectively, when hydrolyzed fungal oil was used. The biocatalyst showed good stability in 5 repeated enzymatic reactions. The physicochemical properties and the ICP-MS analysis of esters demonstrated their potential utilization in cosmetic formulations. This study showed a perspective of valorizing SSL towards the production of value-added fatty acid esters for chemical, cosmetic and pharmaceutical applications.

Analysis of Phosphoinositides from Complex Plant Samples by Solid-Phase Adsorption Chromatography and Subsequent Quantification via Thin-Layer and Gas Chromatography.

The determination of phosphoinositide molecular species in plant material is challenging because of their low abundance concurrent with a very high abundance of other membrane lipids, such as plastidial glycolipids. Phosphoinositides harbor an inositol headgroup which carries one or more phosphate groups at different positions of the inositol, linked to diacylglycerol via a phosphodiester. Thus, a further analytical challenge is to distinguish the different inositol-phosphate headgroups as well as the fatty acids of the diacylglycerol backbone. The method presented in this chapter expands on previous protocols for phosphoinositide analysis by employing chromatographic enrichment of phospholipids and their separation from other, more abundant lipid classes, before analysis. Lipids extracted from plant material are first separated by solid-phase adsorption chromatography into fractions containing neutral lipids, glycolipids, or phospholipids. Lipids from the phospholipid fraction are then separated by thin-layer chromatography (TLC) according to their characteristic head groups, and the individual phosphatidylinositol-monophosphates and phosphatidylinositol-bisphosphates are isolated. Finally, the fatty acids associated with each isolated phosphatidylinositol-monophosphate or phosphatidylinositol-bisphosphate are analyzed in a quantitative fashion using gas chromatography (GC). The analysis of phosphoinositides by this combination of methods provides a cost-efficient and reliable alternative to lipidomics approaches requiring more extensive instrumentation.

Fatty Acid Composition in Fractions of Total Lipids from the Buds of Plants of the Betula L. Genus by the Opening Phases

The fatty acid composition (FAC) of fractions of organic compounds isolated from total lipids (TL) by successive solvents—chloroform, acetone, and methanol, taken as neutral lipids (NL), glycolipids (GL), and phospholipids (PL)—was studied by the phases of the opening of buds in plants of the Betula L. genus [1]. It was found that the FAC of the TL fractions of opening buds of trees with morphological features of Betula pubescens Ehrh., Betula pendula Roth, and Betula pendula Roth var. carelica (Mercklin) Hamet-Ahti is represented mainly by unsaturated fatty acids (USFAs) (up to 88% of the total fatty acids). Linolenic and linoleic acids (up to 55 and 47% of the total fatty acids, respectively) constituted the main share of USFAs. Palmitic acid predominated quantitatively among saturated fatty acids (SFAs) (up to 42%). The content of linoleic acid in all SL fractions decreased with the development of buds in all three birches, while the content of linolenic acid in the composition of the GL and PL fractions increased. In birches differing in morphological characteristics, the specific features of the FAC from the SL fractions of the buds were studied by the opening phases.

Neutral Lipids, Glycolipids, and Phospholipids, Isolated from Sandfish (Arctoscopus japonicus) Eggs, Exhibit Anti-Inflammatory Activity in LPS-Stimulated RAW264.7 Cells through NF-κB and MAPKs Pathways.

Total lipids were extracted from sandfish (Arctoscopus japonicus), and then they were separated into the following three lipid fractions: neutral lipids, glycolipids, and phospholipids. In this study, we analyzed the lipid fractions of A. japonicus eggs and we determined their anti-inflammatory activity in RAW264.7 macrophage cells. In these three lipid-fractions, the main fatty acids were as follows: palmitic acid (16:0), oleic acid (18:1n-9), docosahexaenoic acid (DHA, 22:6n-3), and eicosapentaenoic acid (EPA, 20:5n-3). Among the lipid fractions, phospholipids showed the highest concentration of DHA and EPA (21.70 ± 1.92 and 18.96 ± 1.27, respectively). The three lipid fractions of A. japonicus significantly suppressed the production of NO in macrophages. Moreover, they also significantly inhibited the expression of iNOS, COX-2, IL-6, IL-1β, and TNF-α, in a dose-dependent manner. Furthermore, the lipid fractions of A. japonicus suppressed the nuclear translocation of NF-κB p65 subunits in a dose-dependent manner. In addition, they attenuated the activation of MAPKs (p38, ERK1/2, and JNK) phosphorylation in LPS-stimulated RAW264.7 cells. These results indicate that all the lipid fractions of A. japonicus exert anti-inflammatory activity by suppressing the activation of NF-κB and MAPK pathways. Therefore, the lipid fractions of A. japonicus might be potentially used as anti-inflammatory agents.

Obtaining highly pure EPA-rich lipids from dry and wet Nannochloropsis gaditana microalgal biomass using ethanol, hexane and acetone

Saponifiable lipids (SLs), rich in eicosapentaenoic acid (EPA), were extracted and purified from Nannochloropsis gaditana biomass. Firstly, the SLs were extracted using ethanol (96% v/v). The influence of the following operational variables was studied: water content of the wet biomass, solvent/biomass ratio, homogenization pressure and temperature. SL yields of 92–99 wt% and 80–90 wt% were achieved from dry and wet biomass, respectively, under various operational conditions from batches with different SL contents and lipid profiles. These SLs were extracted with only a 20–22 wt% purity, which was increased to 42% (100 wt% yield) by extracting the SLs with hexane. In this hexane extraction step, it was important to extract the SLs from a highly concentrated hydroethanolic solution. The SL purity was further increased to 95 wt% by acetone crystallization. Throughout this extraction-purification process, SLs were fractionated into neutral lipids, glycolipids and phospholipids - neutral lipids were recovered with higher yields than were glycolipids and phospholipids. The energy consumption per unit mass of extracted lipids was estimated, along with the solvent recovery, and compared for the dry and wet methods. When wet biomass was used, the presence of water significantly increased the energy required for ethanol. However, when cost and capacity of the main equipment (freeze-dryer, homogenizer and centrifuge) were considered, SL extraction from high pressure homogenized wet biomass resulted in a lower economic cost.