Total Lipid Extracts Research Articles

Macromolecular crowding in solution alters huntingtin interaction and aggregation at interfaces

Huntington’s disease (HD) is a fatal neurodegenerative disease caused by an extended polyglutamine (polyQ) domain within the first exon of the huntingtin protein (htt). PolyQ expansion directly invokes the formation of a heterogenous mixture of toxic htt aggregates, including fibrils and oligomers. While htt is a cytosolic protein, it also associates with numerous membranous surfaces within the cell, leading to altered organelle morphology and dysfunction. Here, the impact of macromolecular crowding on htt aggregation in bulk solution and at solid/liquid or membrane/liquid interfaces was investigated. Dextran, Ficoll, and polyethylene glycol (PEG) were used as crowding agents. In bulk solution, crowding enhanced the heterogeneity of non-fibrillar aggregate species formed in a crowder dependent manner. However, crowding agents interfered with the deposition of htt fibrils on mica, suggesting that a crowded aqueous phase influences the interaction of htt with interfaces. By use of in situ atomic force microcopy (AFM), the aggregation of htt directly at mica and bilayer interfaces was tracked. The predominate aggregates type observed to form at the mica interface was fibrillar, but oligomeric aggregates of various stabilities were also observed. Crowding in the aqueous phase suppressed deposition and formation of htt aggregates on mica. In contrast, the addition of crowders enhanced deposition of htt aggregates onto supported total brain lipid extract (TBLE) bilayers. Different crowding agents led to distinct htt aggregates on supported bilayers with unique morphological impact on bilayer integrity. Collectively, these observations point to the complexity of htt aggregation at interfaces and that crowding in the aqueous phase profoundly influences this process.

Coeval Drying Across the Central Tropical Pacific Over the Last Millennium

AbstractHydroclimatic variability in the tropical Pacific reflects large‐scale ocean‐atmosphere processes that imprint on global climate, but tropical Pacific hydroclimate variability over the last millennium remains uncertain. Here we present a multi‐proxy reconstruction from a lacustrine sediment record on Kiritimati Atoll that spans the last millennium. A lake salinity reconstruction from the δ2H values of total lipid extracts, combined with changes in sediment mineralogy and the stable isotopic composition of inorganic carbonates, indicate the presence of several distinct hydrologic regimes on Kiritimati, including a period of persistent aridity from 960–1030 CE, shorter episodes of aridity from 1030–1370 CE, and extreme aridity throughout the latter half of the last millennium, from 1370–1970 CE, that drove complete evaporation of the lake. A period of wetter, variable conditions defines recent decades. Compound‐specific lipid biomarker δ2H values indicate that shifts in microbial community structure occurred in the past, from a community dominated by photoautotrophic and chemoautotrophic organisms in more arid periods to a more metabolically diverse community in the recent period. Comparison of this record with nearby sediment records from Washington Island reveals a similar pattern of aridity through the last millennium, followed by wetter conditions in the modern period. These coherent changes in hydroclimate in the central Pacific are inconsistent with a migration of the Pacific Intertropical Convergence Zone within these latitudes. Rather, past aridity was caused by reduced El Niño‐Southern Oscillation variability, observed through the low‐pass filter of lacustrine records, or by multidecadal to multi‐century strengthening of the Pacific Walker Circulation.

A rapid NMR-based approach for the direct determination of lipid oxidation metabolites in dry fermented cured Italian sausages containing α-tocopherol

The research investigates and demonstrates the potential of the high resolution NMR analysis as a powerful, simple and rapid analytical method to study the extent of lipid oxidation in Italian dry-cured pork sausages containing α-tocopherol. The inclusion of this natural antioxidant additive in the meat products case of study, at levels of 40 mg/Kg and during the manufacturing, considerably increased the resistance to oxidative processes of the total lipid fraction. The effects of adding the natural antioxidant on the lipid oxidation was investigated by proton high-resolution nuclear magnetic resonance (1H HR-NMR) spectroscopy, in dry-cured sausages during storage under vacuum, at 4 °C for 160 days. Higher inhibition of lipid oxidation was observed on the basis of the determination of fatty acid acyl chain profiles in total lipid extracts (TLEs) obtained from sausages, according to a well-known model previously published. In particular, profiles of primary and secondary lipid oxidation products were established, and related to the variation of n-3 fatty acid acyl chains. Lowering of the initial amount of α-tocopherol was also observed on the basis of the variation of the intensities of detectable peaks generated by the resonances of protons present in the molecular structure of the natural antioxidant. The collected results demonstrated the enormous potential of the 1H HR-NMR spectroscopy in investigating the chemical composition of lipids as a meat product shelf-life parameter. Moreover, the findings showed that the application of the selected amount of α-tocopherol was sufficient to decrease lipid oxidation in dry-cured pork sausages, confirming the known properties of this natural antioxidant as a curing agent, as already proved by its use in other different series of fresh and dry-cured chicken sausages, pork salami and fish meat products, especially if fermentation with a nitrate-reducing starter culture is desired

Oxidation of Huntingtin Modulates its Aggregation and Interaction with Membranes

Huntington's disease is an autosomal dominant disease caused by the expansion of a polyglutamine (polyQ) domain within the first exon of the huntingtin (htt) protein. PolyQ expansion promotes htt aggregation into oligomers, b-sheet rich fibrils, and other amorphous species. Htt aggregation is mediated by the first 17 N-terminal amino acids (N17) that directly precede the polyQ domain. In addition, N17 is a membrane binding domain. Both the ability of N17 to enhance htt aggregation and bind lipid membranes are attributed to its ability to form an amphipathic α-helix. N17 also contains several sites for potential posttranslational modifications (PTMs), including oxidation of two methionine residues. Here, the impact of oxidation of methionine residues within N17 on htt aggregation in the presence or absence of lipid membranes comprised of total brain lipid extract (TBLE) was investigated. Two experimental systems were used, a synthetic N-terminal peptide fragment of htt (N17-Q35-P10) and full-length htt-exon1 with 46 repeat glutamines expressed as a GST-fusion protein. For the second system, cleavage of the GST moiety initiates aggregation. To oxidize the methionine residues in N17, the experimental htt systems were treated with hydrogen peroxide. Based on ThT assays, hydrogen peroxide treatment reduced N17-Q35-P10 fibril formation in a dose-dependent manner. Fibrillization of full-length htt-exon1 appeared inhibited with similar hydrogen peroxide treatments as assessed by ex situ atomic force microscopy (AFM) assays. That is, increasing peroxide treatments led to the emergence of shorter and unbranched fibrils while promoting oligomerization. The addition of lipid vesicles generally reduced fibrilization of both experimental systems with and without hydrogen peroxide treatment. However, similar to the trend observed in the absence of lipid, increasing oxidant concentration favored the formation of oligomers. In addition, the aggregation of unoxidized and oxidized htt-exon1 was directly tracked on supported TBLE lipid bilayers using in situ AFM. Both oxidized and unoxidized lipid bilayers were investigated. In general, oxidation of either htt-exon1 alone or both htt and TBLE resulted in reduced membrane damage and disruption. Unoxidized htt deposited quickly and aggressively on TBLE bilayers, forming lumpy amorphous aggregates. With oxidized lipid membranes, htt-exon1 deposited less aggressively on the bilayer, forming a mix of amorphous and smaller grainy oligomeric aggregates over a longer period. In contrast, when both htt-exon1 and TBLE were oxidized, the aggregates formed were mostly grainy oligomeric aggregates. Collectively, these observations suggest that oxidation plays an important role in both the aggregation of htt and its ability to bind lipid membranes, which may ultimately be related to the location of the methionine residues within the amphipathic α-helix of N17.

Direct ethanolic extraction of polar lipids and fractional crystallization from whey protein phospholipid concentrate

Polar lipids, including sphingomyelin (SM) and other sphingolipids, have nutritional implications in many important metabolic pathways. Milk and whey are valuable sources of these bioactive lipids, differing in SM content compared with other plant-based lecithins in the food industry. Dairy lipids were extracted from whey protein phospholipid concentrate powder by direct exposure to a food-grade solvent, ethanol. A total of 20 mass equivalents of solvent was required to completely recover all lipid material of the original whey protein phospholipid concentrate sample. Using a minimal apparatus, absolute ethanol, and heating to a boiling point, a final total lipid extract composed of 37.7% phospholipids (PL) by mass was achieved. The method was developed with potential pilot-scale and industry application in mind. Investigations into fractional crystallization showed limited success at purifying PL from triglyceride content (<1% increase in percent PL by mass). However, the relative percentage of SM was increased in the fractionated sample compared with the total lipid extract. Fatty acid analysis of the PL fraction reported a composition of 33.3% monounsaturated fatty acids and 9.8% polyunsaturated fatty acids. Additional work is needed to investigate different conditions for lipid recovery, PL recovery, and PL purification by fractional crystallization in ethanol.

Rapid Detection of Viral Envelope Lipids Using Lithium Adducts and AP-MALDI High-Resolution Mass Spectrometry.

There is an unmet need to develop analytical strategies that not only characterize the lipid composition of the viral envelope but also do so on a time scale that would allow for high-throughput analysis. With that in mind, we report the use of atmospheric pressure (AP) matrix-assisted laser desorption/ionization (MALDI) high-resolution mass spectrometry (HRMS) combined with lithium adduct consolidation to profile total lipid extracts rapidly and confidently from enveloped viruses. The use of AP-MALDI reduced the dependency of using a dedicated MALDI mass spectrometer and allowed for interfacing the MALDI source to a mass spectrometer with the desired features, which included high mass resolving power (>100000) and tandem mass spectrometry. AP-MALDI combined with an optimized MALDI matrix system, featuring 2',4',6'-trihydroxyacetophenone spiked with lithium salt, resulted in a robust and high-throughput lipid detection platform, specifically geared to sphingolipid detection. Application of the developed workflow included the structural characterization of prominent sphingolipids and detection of over 130 lipid structures from Influenza A virions. Overall, we demonstrate a high-throughput workflow for the detection and structural characterization of total lipid extracts from enveloped viruses using AP-MALDI HRMS and lithium adduct consolidation.

Lipid composition of the microbial mat from a hypersaline environment (Vermelha Lagoon, Rio de Janeiro, Brazil)

ABSTRACTThis study determines organic-matter (OM) composition in the different color layers of a stratified hypersaline microbial mat and verifies the hypothesis that each layer includes a distinct group of lipids. The relation of precursor lipids from the microbial mat to the hydrocarbon composition in fossil records was also evaluated. To that end, the composition was studied of glycolipids (GLs), phospholipids (PLs), and “neutral” lipids (NLs, including hydrocarbons, n-alkanols, sterols, hopanols, free fatty acids, and wax esters) in four different color layers (A–D; depth intervals: up to 0.5 cm, 0.5–1.0 cm, 1.5–3.0 cm, and 3.0–6.0 cm, respectively) of a stratified hypersaline mat from the Vermelha Lagoon, Rio de Janeiro, Brazil.Microscopic characterization revealed the presence of 16 cyanobacterial morphospecies, with predominance of Microcoleus chthonoplastes. The notable prevalence of saturated straight-chain fatty acids (FAs), n-16:0 and n-18:0 and their monounsaturated counterparts, n-16:1 and n-18:1 in all three lipid fractions (GLs, PLs, and NLs), associated with the domination of n-C17 alkane and n-C17:1 alkene among the hydrocarbons confirmed the main imprint of cyanobacteria. The composition of the studied lipid classes implies the contribution of sulfate-reducing bacteria such as Desulfomicrobium sp. strain, purple sulfur bacteria, as well as the possible input of Geobacter spp. and Desulfovibrio spp., particularly in the deeper layers.The notable decrease in total extractable lipids (TELs) yield from layers A to D indicates that lipid synthesis is far more intense by photosynthesizing cyanobacteria than by anaerobic microorganisms. The content of PLs was uniform and low (&amp;lt; 5%) in all layers, implying their extremely quick degradation. GLs, followed by NLs, were the most abundant in all layers indicating the medium, which is characterized by carbon source excess and limited nitrogen source, which regulates microorganism growth. The upper layers, A (green) and B (reddish-brown) differ from those lower, C (dark brown greenish) and D (brown) according to the NLs/GLs ratio, which is higher in the former.The lipid compositions reveal distinctions between the individual layers in the microbial mat. The observed layers clearly differ according to the amount of high-molecular-weight (C22–C31) n-alkanes and long-chain (C21–C30) n-alkanols, the content of phytol, bishomohopanol, tetrahymanol, C27–C29 sterols, the stanol/stenol ratio in the neutral lipid fraction, as well as the content of branched (iso and anteiso) FAs and w9/w7 FA ratio in the GLs fraction. The mentioned parameters imply a greater contribution of sulfate-reducing and purple sulfur bacteria to layer B, higher impact of photosynthetic red algae in upper layers A and B, the elevated contribution of marine ciliate species, feeding on bacteria to layers B and C, as well as the increment of anoxygenic phototrophic and heterotrophic bacteria to layer D. The greatest capability for the synthesis of hydrocarbons is observed in layer B.The composition of lipid classes in the microbial mat showed a significant relationship with the most important biomarkers' fingerprints in the source rocks extracts and petroleum derived from the carbonate hypersaline environments, including the distribution of n-alkanes, a high abundance of phytane and gammacerane, as well as a distribution of C27–C29 regular steranes. Therefore, these results offer an insight into the transformation of microbial OM during the sedimentation processes in a hypersaline environment and its contribution to the fossil record.

Lipidomic analysis of non-esterified furan fatty acids and fatty acid compositions in dietary shellfish and salmon by UHPLC/LTQ-Orbitrap-MS

Lipids such as furan fatty acids (F-acids) are the valuable minor bioactive components of food such as fatty fish and plants. They are reported to have positive health benefits, including antioxidant and anti-inflammatory activities. Despite their importance, limited studies are focusing on F-acid determination in dietary seafood. This study aimed to identify and profile non-esterified F-acids and free fatty acids in total lipid extract of seafood such as shellfish and salmon. The lipidomic analysis using liquid chromatography-linear trap quadrupole-orbitrap mass spectrometry led to identifying seven types of free F-acids in shellfish (n = 5) and salmon (n = 4). The identified F-acids were confirmed by their high-resolution masses and acquired mass spectra. The relative concentrations of F-acids in shellfish range from 0.01 to 10.93 mg/100 g of the fillet, and in salmon, 0.01 to 14.21 mg/100 g of the fillet. The results revealed the highest abundance of F-acids in Sakhalin surf clam, Japanese scallop, and a fatty salmon trout. Besides, relative levels of saturated, monounsaturated, and polyunsaturated fatty acids (PUFAs) in these seafoods were compared with each other, suggesting basket clams and salmon trout to have significantly higher levels of PUFAs. The dietary seafoods enriched with F-acids and PUFAs may have possible health benefits. Hence, the applied technique could be a promising tool for rapid detection and analysis of non-esterified fatty acids in food.

ExoMars Mars Organic Molecule Analyzer (MOMA) Laser Desorption/Ionization Mass Spectrometry (LDI-MS) Analysis of Phototrophic Communities from a Silica-Depositing Hot Spring in Yellowstone National Park, USA.

The Mars Organic Molecule Analyzer (MOMA) is a key scientific instrument on the ExoMars Rover mission. MOMA is designed to detect and characterize organic compounds, over a wide range of volatility and molecular weight, in samples obtained from up to 2 m below the martian surface. Thorough analog sample studies are required to best prepare to interpret MOMA data collected on Mars. We present here the MOMA characterization of Mars analog samples, microbial streamer communities composed primarily of oxygenic and anoxygenic phototrophs, collected from an alkaline silica-depositing hot spring in Yellowstone National Park, Wyoming, USA. Samples of partly mineralized microbial streamers and their total lipid extract (TLE) were measured on a MOMA Engineering Test Unit (ETU) instrument by using its laser desorption/ionization mass spectrometry (LDI-MS) mode. MOMA LDI-MS detected a variety of lipids and pigments such as chlorophyll a, monogalactosyldiacylglycerol, digalactosyldiacylglycerol, diacylglycerols, and β-carotene in the TLE sample. Only chlorophyll a was detected in the untreated streamer samples when using mass isolation, which was likely due to the higher background signal of this sample and the relative high ionization potential of the chlorophyll a compared with other compounds in unextracted samples. The results add to the LDI-MS sample characterization database and demonstrate the benefit of using mass isolation on the MOMA instrument to reveal the presence of complex organics and potential biomarkers preserved in a natural sample. This will also provide guidance to in situ analysis of surface samples during Mars operations.

Filopodium-derived vesicles produced by MIM enhance the migration of recipient cells.

Extracellular vesicles (EVs) are classified as large EVs (l-EVs, or microvesicles) and small EVs (s-EVs, or exosomes). S-EVs are thought to be generated from endosomes through a process that mainly depends on the ESCRT protein complex, including ALG-2 interacting protein X (ALIX). However, the mechanisms of l-EV generation from the plasma membrane have not been identified. Membrane curvatures are generated by the bin-amphiphysin-rvs (BAR) family proteins, among which the inverse BAR (I-BAR) proteins are involved in filopodial protrusions. Here, we show that the I-BAR proteins, including missing in metastasis (MIM), generate l-EVs by scission of filopodia. Interestingly, MIM-containing l-EV production was promoted by invivo equivalent external forces and by the suppression of ALIX, suggesting an alternative mechanism of vesicle formation to s-EVs. The MIM-dependent l-EVs contained lysophospholipids and proteins, including IRS4 and Rac1, which stimulated the migration of recipient cells through lamellipodia formation. Thus, these filopodia-dependent l-EVs, which we named as filopodia-derived vesicles (FDVs), modify cellular behavior.

Effects of the Flanking polyQ Regions and Membrane Physical Properties on Huntingtin Binding to Lipid Vesicles

The pathological expansion of the polyglutamine (polyQ) repeat within the first exon of huntingtin (HTTex1) protein is a hallmark of Huntington’s disease (HD). Multiple evidences support that the membrane interaction of huntingtin is critical for its misfolding and aggregation in HD. Here, we focus on obtaining a detailed understanding of the initial steps of HTTex1-lipid interaction. This characterization has been exceptionally challenging using traditional ensemble methods due to its heterogeneous nature and the high propensity of HTTex1 to aggregate. To overcome these limitations, we used single-molecule approaches based mainly on fluorescence correlation spectroscopy (FCS) to monitor the binding of HTTex1 to synthetic lipid vesicles. The dependence on membrane curvature and lipid composition was studied, considering as models anionic lipids, raft-mimicking mixtures, and total brain lipid extract. The FCS results show a preferential binding of HTTex1 towards POPS (anionic lipid)-containing vesicles of small curvature. Moreover, time-resolved anisotropy measurements reveal distinct conformational dynamics of the adjacent polyQ regions in the HTTex1 membrane-bound state. Notably, the proline-rich domain remains highly flexible and solvent exposed even upon membrane binding. instead, the N17 segment converts into a less dynamic state. Our findings provide unique insight into how membrane curvature/composition and flanking polyQ sequences modulate the early stages of HTTex1 aggregation at the membrane surface. Work supported by FCT-Portugal (PTDC/BIA-BFS/30959/2017 grant and CEECIND/00884/2017 contract to AMM, and UIDB/04565/2020 funding to iBB-IST).

Application of an Improved Chloroform-Free Lipid Extraction Method to Staghorn Coral (Acropora cervicornis) Lipidomics Assessments.

Lipids are excellent biomarkers for assessing coral stress, although staghorn coral data (Acropora cervicornis) is lacking. Lipid extraction is the most critical step in lipidomic assessments, usually performed using carcinogenic solvents. Efficient alternative using less toxic methods, such as the BUME method using butanol and methanol as extraction solvents, have not been applied to coral lipidomics evaluations. Thus, we aimed to develop a lipidomic approach to identify important coral health biomarkers by comparing different solvent mixtures in staghorn corals. Total lipid extraction was equivalent for both tested methods, but due to its efficiency in extracting polar lipids, the BUME method was chosen. It was then applied to different coral masses (0.33-1.00g), resulting in non-significant differences concerning number of lipid classes and compounds. Therefore, this method can be successfully applied to coral assessments in a climate change context, with the added benefit of low sample masses, lessening coral sampling impacts.

Analysis of Free and Esterified Sterol Content and Composition in Seeds Using GC and ESI-MS/MS.

Total sterol content and composition in plant tissues can be easily determined by gas chromatography (GC) after saponification of the total lipid extract. However, in oleogenic tissues a significant proportion of the sterol is esterified to fatty acids, with GC methodologies unable to provide information about the proportion and the molecular species composition of intact steryl esters (SEs). Here we describe an electrospray ionization-tandem mass spectrometry (ESI-MS/MS) and Multiple Reaction Monitoring (MRM) method which, in parallel with GC analysis, allows for the accurate determination of both free and esterified sterol content and composition in seeds. After extraction of seed oil with hexane, free sterols are derivatized with undecanoyl chloride, total steryl esters are then purified from triacylglycerol (TAG) by liquid chromatography, infused and ionized as ammonium adducts, with molecular species identified and quantified by fragmentation in the presence of internal standards.

Conformation-specific perturbation of membrane dynamics by structurally distinct oligomers of Alzheimer's amyloid-β peptide.

The accumulation of toxic soluble oligomers of the amyloid-β peptide (Aβ) is a key step in the pathogenesis of Alzheimer's disease. There are mainly two conformationally distinct oligomers, namely, prefibrillar and fibrillar oligomers, that are recognized by conformation-specific antibodies, anti-amyloid oligomer antibody (A11) and anti-amyloid fibrillar antibody (OC), respectively. Previous studies have shown that the interaction of Aβ oligomers with the lipid membrane is one of the key mechanisms of toxicity produced by Aβ oligomers. However, the mechanism by which structurally distinct Aβ oligomers interact with the lipid membrane remains elusive. In this work, we dissect the molecular mechanism underlying the interaction of structurally distinct Aβ42 oligomers with the lipid membrane derived from the brain total lipid extract. Using picosecond time-resolved fluorescence spectroscopy, we show that the A11-positive Aβ42 oligomers undergo a membrane-induced conformational change that promotes the deeper immersion of these oligomers into the lipid hydrocarbon region and results in an increase in the membrane micro-viscosity. In sharp contrast, OC-positive Aβ42 oligomers interact with the lipid membrane via electrostatic interactions between the negatively-charged lipid headgroup and positively-charged residues of Aβ42 without perturbing the membrane dynamics. We show that the two structurally distinct Aβ42 oligomers demonstrating different interaction mechanisms with the lipid membrane eventually lead to the formation of typical amyloid fibrils. Our findings provide the mechanistic underpinning of the perturbation of lipid membranes by two conformationally distinct Aβ42 oligomers and can be of prime importance in designing anti-Alzheimer's therapeutic agents targeting Aβ-membrane interactions.

Yeast Lipid Extraction and Analysis by HPTLC.

The diversity of lipid structures, properties, and combinations in biological tissues makes their extraction and analysis an experimental challenge. Accordingly, even for one of the simplest single-cellular fungi, the budding yeast (Saccharomyces cerevisiae), numerous extraction and analysis protocols have been developed to separate and quantitate the different molecular lipid species. Among them, most are quite sophisticated and tricky to follow. Herein, we describe a yeast total lipids extraction procedure with a relatively good yield, which is appropriate for subsequent thin-layer chromatography (TLC) or liquid chromatography-mass (LC-MS) analysis. We then discuss the most widely used solvent systems to separate yeast phospholipids and neutral lipids by TLC. Finally, we describe an easy and rapid method for silica gel staining by a Coomassie Brilliant Blue-methanol mixture. The stained lipid species can then be quantitated using imaging software such as ImageJ. Overall, the methods described in this protocol are time-saving and novice-friendly.

Preparation and Characterisation of Biodiesel from Marine Macro-algae Chaetomorpha spp.

The petition for substitute energies has increased in the past numerous years. Several substitutes have come into existence in recent years, and many more are on their way to get established as a sustainable fuel substitute. In the present investigation, we carried out the extraction of total lipids and production of biodiesel from Chetomarpha spp., The algae were collected from the natural habitat of Karwar shoreline region. Different pre-treatment was adopted to dry the collected sample for lipid extraction. The solvent Method was followed to obtain biodiesel at laboratory conditions. GC-MS technique was followed to evaluate the composition of fatty acids in Extracted biodiesel. Quantity of total fatty acid (TFAs) accounted nearly normal in its lipid content composition as in many previous reports. Biofuel experiments have shown promising results towards biodiesel application. The same results have been explained in the appropriate form as given below.

Effect of Milk-Based Infant Formula Fortified with PUFAs on Lipid Profile, Growth and Micronutrient Status of Young Children: A Randomized Double-Blind Clinical Trial.

Background: Polyunsaturated fatty acids (PUFAs) are essential to child growth and development. Objective: To assess the effect of PUFAs-fortified infant formula on lipid profile, growth and micronutrient status in children 12 to 30 months old. Methods: This study is a double-blind randomized controlled clinical trial. Two study groups were assessed: (a) milk-based infant formula with micronutrients and PUFAs (PUFAs) and (b) milk-based infant formula with micronutrients, no PUFAs added (Non-PUFAs). Children received prepared formula (240 mL) twice a day, according to the color-code assigned to each infant. Anthropometric measurements and venous blood samples were taken at each day-care center at baseline, and again after four months. Total serum lipid extraction was 0.5 mL. Samples were treated and modified by the Folch method and analyzed with gas chromatography. Results: Changes in serum lipid profile (expressed as % FA) between baseline and four months showed a statistically significant increase in docosahexaenoic acid (DHA) (0.22 vs. −0.07, p < 0.05) and Alpha-Linoleic acid (0.08 vs. 0.02, p < 0.05) in infants who consumed PUFAs-fortified formula compared to Non-PUFAs-fortified formula. Infants increased their length/height-for-age Z-score: median change for the PUFAs group was 0.16 (95% CI = 0.08, 0.28) and 0.23 (95% CI = 0.14, 0.33) for Non-PUFAs, with no differences between groups. Median folate level was significantly higher among the PUFAs group compared to Non-PUFAs: −0.87 (95% CI = −1.38, −0.44) and −3.83 (95% CI = −4.65, −3.03) respectively. Consumption of both supplements was adequate and stable during the intervention. Conclusion: A significant improvement was observed in the lipid profile of children who received the PUFAs-fortified milk-based formula.

Hydrocarbon transformations in sediments from the Cathedral Hill hydrothermal vent complex at Guaymas Basin, Gulf of California – A chemometric study of shallow seep architecture

Guaymas Basin isa submarine depression in the Gulf of California marking the northern end of the East Pacific Rise mid-oceanic spreading ridge.The basin receives high input of sedimentary organic matter (SOM) from elevated productivity in the overlying surface waters and runoff from the surrounding continent. This, coupled with high sedimentation rates, produces near-uniform compositions of SOM.Various hydrothermal vent complexes occur along this margin. One of these is Cathedral Hill, a hydrothermal mound with sulfide chimneys surrounded by mats dominated by sulfide-oxidizing Beggiatoa, covering sediments stained by locally produced oil. We collected four push cores along a transect at this site (4 m × 0.21 m) extending from near the vent center to the ambient sediment just outside the microbial mat cover. Porewater temperatures near the mound center were projected to reach 155 °C by 21 cm below the sea floor (cmbsf). Within these conditions, a kinetic model based on vitrinite reflectance equivalence (%Re) predicts petroleum formation as shallow as 15–18 cmbsf, with metagenesis commencing at <60 cmbsf. Bulk extract data (total lipid extracts as well as polar and apolar fractions), solvent-extracted sediment TOC (herein referred to as protokerogen TOC), and molecular thermal maturation parameters support these generation estimates. In recent years, the application of chemometric techniques tocomprehensive two-dimensional gas chromatographic (GC × GC) analyses has allowed comparison of thousands of unique hydrocarbons within oils. Here we reconstruct the shallow subsurface petroleum system by applying multiway principal component analysis (MPCA) and hierarchical cluster analysis (HCA)directly to GC × GC chromatograms. We then compare the resulting multivariate models to a systematic survey of subtracted GC × GC chromatograms, a transect heat map of sample hydrocarbon compound diversities, and profiles of various thermal maturation parameters to elucidate how these hydrocarbon matrices are attenuated by production, migration, and/or thermochemical oxidation. Sample matrices have up to 5800 unique compounds spanning a range ofnormal and branched alkanes, saturated and unsaturated biomarkers, substituted and unsubstituted polycyclic aromatic hydrocarbons (PAHs), perhydro-PAHs, and benzothiopheneswith up to six ring-cycles (i.e., benzoperylenes, dibenzopyrenes, dibenzochrysenes, and indenopyrenes). These matrices display systematic temperature-dependent trends. Generation likely begins in 6–10 and 15–18 cmbsf where sediments are exposed to ∼115 °C vent porewater temperatures, which is shallower than predictions based on our kinetic model. Independent of these sites of generation is ubiquitous staining of the sediments from advected oil that is heavily dominated by PAHs as well as two stratigraphic bandsof migrated oil that extend horizontally across the transect at 0–2 and ∼6–10 cmbsf, respectively.The MPCA models along with non-statistical validation techniques show evidence of decreasingdiversities and concentrations of alkylated aromatic hydrocarbons concomitant with elevated abundances of dealkylated PAHs and/or the migration of unsubstituted PAHs from deeper basin depths as sediments become exposed to more severe hydrothermal conditions. These results indicate that even at relatively small spatial scales, the petroliferous sediments at hydrothermal vent sites can be highly complex.

Phosphomimetic Mutations Impact Huntingtin Aggregation in the Presence of a Variety of Lipid Systems.

Huntington's disease (HD) is a neurodegenerative disorder caused by the abnormal expansion of a polyglutamine (polyQ) tract in the first exon of the htt protein (htt). PolyQ expansion triggers the aggregation of htt into a variety of structures, including oligomers and fibrils. This aggregation is impacted by the first 17 N-terminal amino acids (Nt17) of htt that directly precedes the polyQ domain. Beyond impacting aggregation, Nt17 associates with lipid membranes by forming an amphipathic α-helix. Post-translational modifications within Nt17 are known to modify HD pathology, and in particular, phosphorylation at T3, S13, and/or S16 retards fibrillization and ameliorates the phenotype in HD models. Due to Nt17's propensity to interact with lipid membranes, the impact of introducing phosphomimetic mutations (T3D, S13D, and S16D) into htt-exon1 on aggregation in the presence of a variety of model lipid membranes (total brain lipid extract, 1-palmitoyl-2-oleoyl-glycero-3-phosphatidylcholine, and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-1'-rac-glycerol) was investigated. Phosphomimetic mutations altered htt's interaction with and aggregation in the presence of lipids; however, this was dependent on the lipid system.

Cholestasis impairs hepatic lipid storage via AMPK and CREB signaling in hepatitis B virus surface protein transgenic mice

AbstractClinical studies demonstrated that nonalcoholic steatohepatitis is associated with liver-related outcomes in chronic hepatitis B. Furthermore, primary biliary fibrosis and biliary atresia occurred in patients with HBV infection. Interestingly, hepatitis B virus surface protein (HBs) transgenic mice spontaneously develop hepatic steatosis. Our aim is to investigate the effect of Abcb4 knockout-induced cholestasis on liver steatosis in HBs transgenic mice. Hybrids of HBs transgenic and Abcb4−/− mice were bred on the BALB/c genetic background. Lipid synthesis, storage, and catabolism as well as proteins and genes that control lipid metabolism were analyzed using HPTLC, qPCR, western blot, electrophoretic mobility shift assay (EMSA), lipid staining, and immunohistochemistry. Hepatic neutral lipid depots were increased in HBs transgenic mice and remarkably reduced in Abcb4−/− and HBs/Abcb4−/− mice. Similarly, HPTLC-based quantification analyses of total hepatic lipid extracts revealed a significant reduction in the amount of triacylglycerols (TAG), while the amount of free fatty acids (FFA) was increased in Abcb4−/− and HBs/Abcb4−/− in comparison to wild-type and HBs mice. PLIN2, a lipid droplet-associated protein, was less expressed in Abcb4−/− and HBs/Abcb4−/−. The expression of genes-encoding proteins involved in TAG synthesis and de novo lipogenesis (Agpat1, Gpat1, Mgat1, Dgat1, Dgat2, Fasn, Hmgcs1, Acc1, Srebp1-c, and Pparγ) was suppressed, and AMPK and CREB were activated in Abcb4−/− and HBs/Abcb4−/− compared to wild-type and HBs mice. Simulating cholestatic conditions in cell culture resulted in AMPK and CREB activation while FASN and PLIN2 were reduced. A concurrent inhibition of AMPK signaling revealed normal expression level of FASN and PLIN2, suggesting that activation of AMPK–CREB signaling regulates hepatic lipid metabolism, i.e. synthesis and storage, under cholestatic condition. In conclusions, in vivo and mechanistic in vitro data suggest that cholestasis reduces hepatic lipid storage via AMPK and CREB signaling. The results of the current study could be the basis for novel therapeutic strategies as NASH is a crucial factor that can aggravate chronic liver diseases.The authors demonstrate that cholestasis impairs hepatic lipid storage via AMP-activated protein kinase (AMPK) and CREB signaling in hepatitis B virus surface protein transgenic mice. The pharmacological modulation of AMPK and CREB signaling might be a promising therapeutic concept for the treatment of fatty liver diseases.