Ether Lipids Research Articles

Determining the double-bond positions of monounsaturated compounds in the alcohol fraction in seep carbonate

The unsaturation patterns of molecular fossils are critical in distinguishing their biological precursors and diagenetic processes. However, questions regarding the determination of double-bond positions of unsaturated dialkyl glycerol ethers (DAGEs) in submarine hydrocarbon seep ecosystems remain unsolved. To address this problem, a protocol for dimethyl disulfide (DMDS) derivative analysis using gas chromatography (GC)-mass spectrometry was optimised. Herein, the double-bond positions of monounsaturated short-chain alcohols, monoalkyl glycerol ethers (MAGEs), and DAGEs in seep carbonates were analysed. Among these compounds, the double-bond positions of trimethylsilyl (TMS) derivatives of the monounsaturated DAGE-DMDS adducts were determined for the first time, with mass spectra characterized by molecular ions (M+·) and two major diagnostic ions (ω+ and Δ+) cleaved at the double bonds. For both the MAGEs and DAGEs, the double-bond positions of the monounsaturated n-C16:1-alkyl moieties were identified at ω5 and ω7. Compared to monounsaturated short-chain alcohols and MAGEs, both ionization efficiency and relative sensitivity for the TMS derivatives of DAGE-DMDS adducts were low as indicated by the high limit of detection at a signal-to-noise ratio of 3. In addition, the appropriate injection parameters and oven temperature program during GC analyses may be crucial in determining the double-bond positions within monounsaturated DAGEs.

Improved Hydrotropic Extraction of Carnosic Acid from Rosemary and Sage with Short-Chain Monoalkyl Glycerol Ethers

Hydrotropic extraction in water with biobased amphiphiles is considered as an interesting alternative to conventional extraction with organic solvents. In this study, butyl, isoamyl, and pentyl glycerol ethers (C4Gly, iC5Gly, and C5Gly, respectively) are investigated for the extraction from rosemary (Rosmarinus officinalis) and sage (Salvia officinalis) of carnosic acid (CA), a powerful natural antioxidant used as an alternative to synthetic ones in food and cosmetic industries. First, interactions between CA and hydrotropes are studied to set the extraction conditions, resulting in the measurement of the solubility curves and miscibility of CA in the hydrotropic solutions. Then, C5Gly is shown to have the highest efficiency to extract CA, which is rationalized with a molecular model previously established for an alkyl polyethylene glycol ether (CiEj) series of amphiphiles based on their log P and molecular volume. Additionally, measurement of the contact angles of the hydrotropic solutions on rosemary leaves indicates that the efficiency of the hydrotrope is also dependent on the interfacial tension.

Seminal lipid profiling and antioxidant capacity: A species comparison.

On their way to the oocyte, sperm cells are subjected to oxidative stress, which may trigger the oxidation of phospholipids (PL). Applying MALDI-TOF MS, HPTLC and ESI-IT MS, we comparatively analyzed the PL compositions of semen and blood of species differing in their reproductive systems and types of nutrition (bull, boar, stallion, lion and man) with regard to the sensitivity to oxidation as well as the accumulation of harmful lyso-PL (LPL), transient products of lipid oxidation. In addition, the protective capacity of seminal fluid (SF) was also examined. The PL composition of erythrocytes and blood plasma is similar across the species, while pronounced differences exist for sperm and SF. Since the blood function is largely conserved across mammalian species, but the reproductive systems may vary in many aspects, the obtained results suggest that the PL composition is not determined by the type of nutrition, but by the relatedness of species and by functional requirements of cell membranes such as fluidity. Sperm motion and fertilization of oocytes require a rather flexible membrane, which is accomplished by significant moieties of unsaturated fatty acyl residues in sperm lipids of most species, but implies a higher risk of oxidation. Due to a high content of plasmalogens (alkenyl ether lipids), bull sperm are most susceptible to oxidation. Our data indicate that bull sperm possess the most effective protective power in SF. Obviously, a co-evolution of PL composition and protective mechanisms has occurred in semen and is related to the reproductive characteristics. Although the protective capacity in human SF seems well developed, we recorded the most pronounced individual contaminations with LPL in human semen. Probably, massive oxidative challenges related to lifestyle factors interfere with natural conditions.

Molecular and isotopic signatures of oil-driven bacterial sulfate reduction at seeps in the southern Gulf of Mexico

Oil seepage is widespread in the Gulf of Mexico, which also applies to the Bay of Campeche in the southern Gulf. The ascension of crude oil and oil-derived hydrocarbons poses a challenge to most seep-dwelling organisms. On the other hand, short- and long-chain hydrocarbons have been shown to be potentially degraded by a range of heterotrophic sulfate-reducing bacteria. Here we present lipid biomarker and carbon isotope data from authigenic carbonates from the Campeche Knolls in the southern Gulf of Mexico and use methane-seep carbonates from the Makran convergent margin (southern Pakistan and Iran) for comparison. The Campeche Knolls and Makran were selected for such comparison as endmember types for oil versus methane seepage in an attempt to identify molecular signatures of oil seepage. The Campeche carbonates yielded on average higher δ13C values (−31.3‰ to −21.9‰) than the Makran methane-seep carbonates (−54.3‰ to −39.8‰) and revealed a particularly high content of ether lipids. The Campeche carbonates revealed a greater variety of alkyl chains in non-isoprenoidal dialkyl glycerol diether lipids (DAGE) and a higher relative proportion of long alkyl chains (DAGEs >C36) compared with the Makran methane-seep carbonates. Bacterial biomarkers showed an on average distinctively heavier δ13C signature than at the studied methane seeps, indicating bacterial oxidation of oil-derived hydrocarbons. Mixing calculations indicate that up to 73% of the local sulfate reduction is coupled to the oxidation of non-methane hydrocarbons at the oil seeps, contributing as much as 40% to carbonate precipitation. These data imply that oil-seep carbonates can be discriminated from methane-seep carbonates by their respective biomarker inventories in modern and, in cases of moderate to good biomarker preservation, ancient environments, setting the stage for the reconstruction of the influence of fluid composition on the compositions of chemosynthesis-based communities at seeps.

Elucidation of the Mechanisms and Effective Substances of Paeoniae Radix Rubra Against Toxic Heat and Blood Stasis Syndrome With a Stage-Oriented Strategy.

In the clinical practice of traditional Chinese medicine, toxic heat and blood stasis syndrome (THBSS) is a common syndrome observed in various critical diseases. Paeoniae Radix Rubra (PRR) has known therapeutic effects on THBSS. However, its pharmacodynamic mechanisms and effective substances in the treatment of THBSS still need further elucidation. Our previous study indicated that THBSS had three stages of progression, and the abnormal biochemical indices of each stage were different. Therefore, this study aimed to elucidate the pharmacodynamic mechanisms and effective substances of PRR for the treatment of THBSS with a stage-oriented strategy. Specifically, research was performed separately in two stable stages of THBSS: the excessive heat and little blood stasis (EHLBS) and blood stasis (BS) stages. THBSS model rats, at different time periods after syndrome initiation (first 5 h for EHLBS and 24 h later for BS), were used to conduct the two-stage investigation. Targeted metabonomics analysis was performed to elucidate the pharmacodynamic mechanisms of PRR in the treatment of EHLBS or BS. Based on the relationship between the individual differences in blood drug concentrations and pharmacodynamic effects, partial least squares regression analysis was employed to screen for the effective substances from the original constituents and metabolites of PRR. We found that PRR could upregulate primary bile acid biosynthesis, glycerophospholipid metabolism, ether lipid metabolism, and five amino acid metabolic pathways (e.g., arginine and proline metabolism) to treat EHLBS. Meanwhile, PRR alleviated BS by upregulating primary bile acid biosynthesis and downregulating glycerophospholipid metabolism. But PRR had no obvious effects on ether lipid metabolism and amino acid metabolism in this stage. In total, 17 and 9 potential effective substances were found in the EHLBS and BS stages, respectively, among which there were only five common compounds between the two stages. To our knowledge, sixteen compounds were regarded as potential effective substances of PRR for the first time. Therefore, the pharmacodynamic mechanisms and effective substances of PRR in the treatment of EHLBS and BS were partly different. Overall, this stage-oriented strategy provides a new way to study the pharmacodynamic mechanisms and effective substances of traditional Chinese drugs.

Ether Lipids in Obesity: From Cells to Population Studies.

Ether lipids are a unique class of glycero- and glycerophospho-lipid that carry an ether or vinyl ether linked fatty alcohol at the sn-1 position of the glycerol backbone. These specialised lipids are important endogenous anti-oxidants with additional roles in regulating membrane fluidity and dynamics, intracellular signalling, immunomodulation and cholesterol metabolism. Lipidomic profiling of human population cohorts has identified new associations between reduced circulatory plasmalogen levels, an abundant and biologically active sub-class of ether lipids, with obesity and body-mass index. These findings align with the growing body of work exploring novel roles for ether lipids within adipose tissue. In this regard, ether lipids have now been linked to facilitating lipid droplet formation, regulating thermogenesis and mediating beiging of white adipose tissue in early life. This review will assess recent findings in both population studies and studies using cell and animal models to delineate the functional and protective roles of ether lipids in the setting of obesity. We will also discuss the therapeutic potential of ether lipid supplementation to attenuate diet-induced obesity.

Electrostatic spraying synthesis of energetic RDX@NGEC nanocomposites

It displays a favorable spherical morphology of the energetic RDX@NGEC nanocomposites and the 3D distribution of Raman mapping images, as well as the gas products detected by IR, and the mechanism of the desensitization. • Electrospray technology is utilized to assemble a novel energetic RDX@NGEC nanocomposites successfully. • The obtained RDX@NGEC composites exhibit favorable thermal decomposition and significant reduced sensitivity. • The mechanism of coating process, thermal decomposition and desensitization was proposed and discussed. • This construction strategy of novel energetic binder NGEC-based composites provides an application potential in propellants. Recently, an emerging category of thermal plastic energetic binder: nitrate glycerol ether cellulose (NGEC) exhibits promising application in propellants with extraordinary mechanical performance, and can be considered for using in military system instead (or partial) of traditional nitrocellulose (NC). In this paper, the electrostatic spraying technology is performed to synthesis a novel kind of nanocomposites energetic materials (nEMs) (hexahydro-1,3,5-trinitro-1,3,5-triazine) RDX@NGEC by adjusting the mass ratio of NGEC:RDX (0:5 ∼ 2.5:2.5). The results demonstrate that the NGEC patches with content of 30% were coated relatively uniformly on the surface of RDX crystal, and an ideal spherical structure, with dramatically reduced particle size (100 ∼ 800 nm) was obtained. Most importantly, the thermal decomposition properties are investigated systematically by traditional DSC (differential scanning calorimeter) analysis, DSC-TG-IR (DSC-thermogravimetric analysis-fourier-transform infrared spectroscopy) combining technology, where the kinetic parameters of thermal decomposition reaction are also calculated by two traditional methods: the Kissinger and Ozawa methods. It reveals that the process of the decomposition is mainly controlled by RDX when content of NGEC is low (10%∼20%), and the decomposition peak of NGEC is gradually appearing with the increasing content of NGEC (30%∼50%). Furthermore, the impact and friction sensitivities are tested and have been reduced about 1 ∼ 3 times. The mechanism of the sensitivity reduction, coating process and decomposition are also discussed detailly. Hence, this preparation and properties strategy of novel energetic RDX@NGEC nanocomposites may provide foundational theory research and exhibits application potential in propellants and explosives.

Acidity and Stability of Brønsted Acid Sites in Green Clinoptilolite Catalysts and Catalytic Performance in the Etherification of Glycerol

Natural zeolite clinoptilolite CLIN with a framework ratio of Si/Al ≥ 4 containing mainly potassium and calcium ions in its internal channel system was used as a starting material. The acidic HCLIN catalysts were prepared under soft conditions avoiding the use of environmental less-benign mineral acids. The starting material was ion exchanged using a 0.2 M aqueous ammonium nitrate solution at a temperature 80 °C for 2 h. The obtained NH4CLIN was converted into the acid HCLIN catalyst by calcination at 300–600 °C. The obtained samples were characterized by XRD, FTIR, SEM/TEM, AAS, and EDX element mapping. The state of aluminium and silicon was studied by 27Al- and 29SiMAS NMR spectroscopy. The textural properties of the catalysts were investigated by nitrogen adsorption and desorption measurements. The Brønsted acidity of the HCLIN catalysts was studied by temperature-programmed decomposition of the exchanged ammonium ions releasing ammonia as well as 1H MAS NMR, {1H–27Al} Trapdor, and {1H–27Al} Redor experiments. The strongly agglomerated samples were crystalline and thermally stable up to >500 °C. Although a part of the clinoptilolite framework is maintained up to 600 °C, a loss of crystallinity is already observed starting from 450 °C. The specific surface areas of the starting CLIN and ammonium exchanged NH4CLIN are low with ca. 26 m2/g. The pores are nearly blocked by the exchangeable cations located in the zeolite pores. The thermal decomposition of the ammonium ions by calcination at 400 °C causes an opening of the pore entrances and a markable increase in the specific micropore area and micropore volume to ca. 163 m2/g and 0.07 cm3/g, respectively. It decreases with further rising calcination temperature indicating some structural loss. The catalysts show a broad distribution of Brønsted acid sites (BS) ranging from weak to strong sites as indicated the thermal decomposition of exchanged ammonium ions (TPDA). The ammonium ion decomposition leaving BS, i.e., H+ located at Al–O–Si framework bridges, starts at ≥250 °C. A part of the Brønsted sites is lost after calcination specifically at 500 °C. It is related to the formation of penta-coordinated aluminium at the expense of tetrahedral framework aluminium. The Brønsted sites are partially recreated after repeated ammonium ion exchange. The catalytic performance of the acidic HCLIN catalysts was tested in the etherification of glycerol as a green renewable resource with different C1-C4 alcohols. The catalysts are highly active in the etherification of glycerol, especially with alcohols containing the branched, tertiary alkyl groups. Highest activity is observed with the soft activated catalyst HCLIN300 (300 °C, temperature holding time: 1 min). A total of 78% conversion of glycerol to mono and di ether were achieved with tert-butanol at 140 °C after 4 h of reaction. The mono- and di-ether selectivity were 75% and 25%, respectively. The catalyst can be reused.

The Inorganic Perovskite-Catalyzed Transfer Hydrogenation of Cinnamaldehyde Using Glycerol as a Hydrogen Donor

Catalytic transfer hydrogenation reactions (CTHs) produce value-added chemicals in the most economical, safe, green, and sustainable way. However, understanding the reaction mechanism and developing stable, selective, and cheap catalysts has been a significant challenge. Herein, we report on the hydrogenation of cinnamaldehyde utilizing glycerol as a hydrogen donor and metal-oxides (SnO2, LaFeO3, and LaSnO3) as heterogeneous catalysts. The perovskite types were used because they are easy to synthesize, the metal components are readily available, and they are good alternatives to noble metals. The catalysts were synthesized through the nanocasting (hard-template) method with SiO2 (KIT-6) as a template. The template was synthesized using the soft-template (sol-gel) method resulting in a high surface area of 624 m2/g. Furthermore, catalytic evaluations gave high cinnamaldehyde percentage conversions of up to 99%. Interestingly, these catalysts were also found to catalyze the etherification of glycerol in one pot. Therefore, we propose competitive surface catalytic reactions driven by the transition metal cations as the binding sites for the cinnamaldehyde and the sacrificial glycerol.

Mice with a deficiency in Peroxisomal Membrane Protein 4 (PXMP4) display mild changes in hepatic lipid metabolism

Peroxisomes play an important role in the metabolism of a variety of biomolecules, including lipids and bile acids. Peroxisomal Membrane Protein 4 (PXMP4) is a ubiquitously expressed peroxisomal membrane protein that is transcriptionally regulated by peroxisome proliferator-activated receptor α (PPARα), but its function is still unknown. To investigate the physiological function of PXMP4, we generated a Pxmp4 knockout (Pxmp4−/−) mouse model using CRISPR/Cas9-mediated gene editing. Peroxisome function was studied under standard chow-fed conditions and after stimulation of peroxisomal activity using the PPARα ligand fenofibrate or by using phytol, a metabolite of chlorophyll that undergoes peroxisomal oxidation. Pxmp4−/− mice were viable, fertile, and displayed no changes in peroxisome numbers or morphology under standard conditions. Also, no differences were observed in the plasma levels of products from major peroxisomal pathways, including very long-chain fatty acids (VLCFAs), bile acids (BAs), and BA intermediates di- and trihydroxycholestanoic acid. Although elevated levels of the phytol metabolites phytanic and pristanic acid in Pxmp4−/− mice pointed towards an impairment in peroxisomal α-oxidation capacity, treatment of Pxmp4−/− mice with a phytol-enriched diet did not further increase phytanic/pristanic acid levels. Finally, lipidomic analysis revealed that loss of Pxmp4 decreased hepatic levels of the alkyldiacylglycerol class of neutral ether lipids, particularly those containing polyunsaturated fatty acids. Together, our data show that while PXMP4 is not critical for overall peroxisome function under the conditions tested, it may have a role in the metabolism of (ether)lipids.

Thermodynamic equilibrium analysis on the dehydration of glycerol with monohydric alcohols to alkyl glyceryl ethers

AbstractUnder the conditions of the feed of 400 moles of alcohol + 100 moles of glycerol, 313–573 K and 0.1 MPa, based on Gibbs free energy global minimization, an improved genetic algorithm was used for the thermodynamic equilibrium analysis on the synthesis processes of alkyl glyceryl ethers, respectively, from methanol + glycerol, ethanol + glycerol, isobutanol + glycerol, and tert‐butanol + glycerol. The columnar stacking charts and three‐dimensional contour graphs were used to compare the effects of temperature, pressure, and the feed ratio to the equilibrium conversion, product selectivity, and equilibrium composition. The basic laws of the synthesis processes of alkyl glycerol ethers in homogeneous and heterogeneous states were investigated in a wide temperature range. Through comparison, it was found that the isopropanol + glycerol system is easier to convert into alkyl glycerol ethers, followed by the ethanol + glycerol system. The methanol + glycerol system and tert‐butanol + glycerol system are greatly affected by pressure and temperature, and their conversions and selectivities are relatively low.

Investigating the role of membrane dipole potential in liquid-liquid phase separation: ether lipids influence domain size

Lateral lipid heterogeneity is thought to play an important role in the functioning of cell membranes. Parameters such as the shape, size, and composition of domains are not well-understood in biological membranes, in part because of their chemical complexity. Factors including line tension, dipole repulsions, and thermal fluctuations contribute to these parameters. To elucidate the impact of these factors, we use simple three- or four- component model membranes. Liquid-liquid phase separation in these systems have provided numerous insights into the behavior of domains in biological membranes.

Peroxisomal Stress Response and Inter-Organelle Communication in Cellular Homeostasis and Aging.

Peroxisomes are key regulators of cellular and metabolic homeostasis. These organelles play important roles in redox metabolism, the oxidation of very-long-chain fatty acids (VLCFAs), and the biosynthesis of ether phospholipids. Given the essential role of peroxisomes in cellular homeostasis, peroxisomal dysfunction has been linked to various pathological conditions, tissue functional decline, and aging. In the past few decades, a variety of cellular signaling and metabolic changes have been reported to be associated with defective peroxisomes, suggesting that many cellular processes and functions depend on peroxisomes. Peroxisomes communicate with other subcellular organelles, such as the nucleus, mitochondria, endoplasmic reticulum (ER), and lysosomes. These inter-organelle communications are highly linked to the key mechanisms by which cells surveil defective peroxisomes and mount adaptive responses to protect them from damages. In this review, we highlight the major cellular changes that accompany peroxisomal dysfunction and peroxisomal inter-organelle communication through membrane contact sites, metabolic signaling, and retrograde signaling. We also discuss the age-related decline of peroxisomal protein import and its role in animal aging and age-related diseases. Unlike other organelle stress response pathways, such as the unfolded protein response (UPR) in the ER and mitochondria, the cellular signaling pathways that mediate stress responses to malfunctioning peroxisomes have not been systematically studied and investigated. Here, we coin these signaling pathways as “peroxisomal stress response pathways”. Understanding peroxisomal stress response pathways and how peroxisomes communicate with other organelles are important and emerging areas of peroxisome research.

THEM6‐mediated reprogramming of lipid metabolism supports treatment resistance in prostate cancer

Despite the clinical benefit of androgen‐deprivation therapy (ADT), the majority of patients with advanced prostate cancer (PCa) ultimately develop lethal castration‐resistant prostate cancer (CRPC). In this study, we identified thioesterase superfamily member 6 (THEM6) as a marker of ADT resistance in PCa. THEM6 deletion reduces in vivo tumour growth and restores castration sensitivity in orthograft models of CRPC. Mechanistically, we show that the ER membrane‐associated protein THEM6 regulates intracellular levels of ether lipids and is essential to trigger the induction of the ER stress response (UPR). Consequently, THEM6 loss in CRPC cells significantly alters ER function, reducing de novo sterol biosynthesis and preventing lipid‐mediated activation of ATF4. Finally, we demonstrate that high THEM6 expression is associated with poor survival and correlates with high levels of UPR activation in PCa patients. Altogether, our results highlight THEM6 as a novel driver of therapy resistance in PCa as well as a promising target for the treatment of CRPC.

Enrichment of n-3 containing ether phospholipids in plasma after 30 days of krill oil compared with fish oil supplementation.

There are conflicting findings over the bioavailability of long-chain n-3 polyunsaturated fatty acids (n-3 PUFA) from krill oil (KO) compared with fish oil (FO) in short- and long-term studies. The aim of this study was to compare the effects of KO versus FO on the enrichment of molecular species of plasma phospholipids in young women following a 30-day consumption of the n-3 oils. Eleven healthy women aged 18-45 years consumed seven capsules of KO per day (containing a total of 1.27 g n-3 PUFA) or five capsules of FO per day (total of 1.44 g n-3 PUFA) for 30 days in a randomized crossover study, separated by at least a 30-day washout period. Fasting blood samples were collected at day zero (baseline), day 15 and day 30 and analyzed by HPLC-MS/MS for molecular species of phospholipids. Supplementation increased n-3 PUFA in main phospholipids classes in both groups. After 30 days of supplementation, 35 out of 70 molecular species containing eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPAn-3) had a significantly greater concentration in KO group compared with the FO treated group. The majority (89%) of the differentiated molecular species were choline and ethanolamine ether-phospholipids. These data reveal that analysis of plasma phospholipids following 30 days of consumption of KO (a marine oil rich in phospholipids, including ether phospholipids) resulted in an enrichment of n-3 PUFA in molecular species of ether-phospholipids compared with FO (a triacylglycerol-rich marine oil).

Heterogeneous thermodynamic comparison of the tert-butyl glycerol ether synthesis from glycerol via olefin etherification or alcohol dehydration

On the basis of the principle of Gibbs free energy minimization, a genetic algorithm was used to carry out a comparative study on the heterogeneous thermodynamics of the glycerol etherification with isobutanol, and the glycerol dehydration with tert-butanol to butyl glycerol ethers. Under the conditions in the temperature range of 40-300 °C, the pressure range of 0.1-0.7 MPa, the feed of 100 mol of glycerol + 600 mol of other reactant, the effects of temperature and pressure on the equilibrium conversions, product selectivities and gas-liquid equilibrium composition were investigated. The results show that for the etherification process, low temperature is conducive to the generation of tri-tert-butyl glycerol ether, while high temperature is conducive to the generation of di-tert-butyl glycerol ether and mono-tert-butyl glycerol ether. The elevated pressures promote the formation of tri-tert-butyl glycerol, while inhibit the production of di-tert-butyl glycerol ether and mono-tert-butyl glycerol ether. For the dehydration process, the equilibrium conversion of glycerol is close to 100%, the selectivity of tri-tert-butyl glycerol ether is more than 90%, the selectivity of di-tert-butyl glycerol ether is less than 10%, and mono-tert-butyl glycerol ether is efficiently converted. The results also show that for the dehydration process, increasing the pressure moves the heterogeneous temperature range to the right, and the liquid phase composition can be adjusted by changing the pressure.

Quantitative analysis of the serum proteome during early pregnancy in mares.

Equine pregnancy is currently diagnosed by rectal palpation, ultrasonographic examination, or by measuring changes in hormones in the blood. In the present study, we identified proteins that are differentially expressed in the sera of early pregnant and non-pregnant mares in order to develop a novel method for diagnosing equine pregnancy. Serum samples were obtained from 18 adult mares, pregnancy at day 32 after ovulation (n = 9) and in diestrus (n = 9). Proteomic analysis of the samples was conducted using liquid chromatography-electrospray ionization-tandem mass spectrometry. We identified 467 proteins from a total of 3514 peptides. Thirty-two proteins (15 upregulated and 17 downregulated) were significantly differentially expressed between the two groups. The Gene Ontology enrichment analysis revealed that they are related to extracellular matrix assembly, blood coagulation, and hemostasis, and the prominent molecular functions were integrin binding, cell adhesion molecule binding, and glycine C-acetyltransferase activity. The pathway analysis of Kyoto Encyclopaedia of Genes and Genomes showed that the top three pathways identified were glycine, serine, and threonine metabolism; cysteine and methionine metabolism; and ether lipid metabolism. The selected five serum proteins were newly potential candidates for pregnancy diagnosis in mares.

Serum metabolomics analysis reveals amelioration effects of sea cucumber ether phospholipids on oxidative stress and inflammation in high-fat diet-fed mice.

Emerging evidence suggests that sea cucumber ether phospholipids (ether-PLs) can modulate high-fat diet (HFD)-induced metabolic disorders. However, whether this modulation is associated with metabolic pathways related to oxidative stress and inflammation remains unclear. This study aimed to investigate the antioxidative and anti-inflammatory effects on HFD-fed mice and the associated metabolism pathways in response to administration with sea cucumber ether-PLs using integrated biochemistry and a metabolomics approach. Biochemistry analysis and histological examinations showed that sea cucumber ether-PLs significantly decreased body weight gain and fat deposition in tissues. PE-P was superior to PC-O in alleviating reactive oxygen species (ROS), malondialdehyde (MDA) and inflammatory responses (IL-6, TNF-α and MCP-1) in the HFD-induced mouse model. Serum metabolomics analysis revealed that it upregulated four metabolites and downregulated twenty-four metabolites compared to those in HFD mice after ether-PL administration. Pathway analysis indicated that sea cucumber ether-PLs alleviate the HFD-induced inflammation and oxidative stress by three main metabolic pathways, namely fatty acid metabolism, branched-chain amino acid (BCAA) metabolism, and trichloroacetic acid (TCA) metabolism. Taken together, sea cucumber ether-PLs showed great potential to become a natural functional food against oxidative stress and inflammation caused by HFD.

Phosphatidic acid phosphatase 1 impairs SARS-CoV-2 replication by affecting the glycerophospholipid metabolism pathway.

Viruses exploit the host lipid metabolism machinery to achieve efficient replication. We herein characterize the lipids profile reprogramming in vitro and in vivo using liquid chromatography-mass spectrometry-based untargeted lipidomics. The lipidome of SARS-CoV-2-infected Caco-2 cells was markedly different from that of mock-infected samples, with most of the changes involving downregulation of ceramides. In COVID-19 patients' plasma samples, a total of 54 lipids belonging to 12 lipid classes that were significantly perturbed compared to non-infected control subjects' plasma samples were identified. Among these 12 lipid classes, ether-linked phosphatidylcholines, ether-linked phosphatidylethanolamines, phosphatidylcholines, and ceramides were the four most perturbed. Pathway analysis revealed that the glycerophospholipid, sphingolipid, and ether lipid metabolisms pathway were the most significantly perturbed host pathways. Phosphatidic acid phosphatases (PAP) were involved in all three pathways and PAP-1 deficiency significantly suppressed SARS-CoV-2 replication. siRNA knockdown of LPIN2 and LPIN3 resulted in significant reduction of SARS-CoV-2 load. In summary, these findings characterized the host lipidomic changes upon SARS-CoV-2 infection and identified PAP-1 as a potential target for intervention for COVID-19.

Sulfonated organosilica-aluminum phosphates as useful catalysts for acid-catalyzed reactions: Insights into the effect of synthesis parameters on the final catalyst

The synthesis, by a sol-gel method, of organosilica-aluminum phosphates, (X)-AlPO(Y)-(Z), using three different silica precursors (X) 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane (C), 3-(mercaptopropyl)trimethoxysilane (MPTMS) or Bis[3-(triethoxysilyl)propyl]tetrasulfide (B), with varying Al/P molar ratio (Y = 3–10) and pH of the final gel (Z = 3–9), maintaining an Al/Si= 3 molar ratio, has been carried out. Materials were characterized by XRF, SEM-EDX, XRD, 1H–29Si CP, 27Al and 31P MAS NMR and nitrogen adsorption. The acidity of the solids was evaluated by TGA, XRF and XPS and their catalytic behavior in the etherification of glycerol with tert-butyl alcohol, under microwave irradiation. The solids with an Al/P molar ratio between 3 and 6, synthesized at a pH value over 3 with precursor C, exhibiting the highest values of acidity and predominantly a mesoporous character, showed the best catalytic behavior.