A GDSL motif-containing lipase modulates Sclerotinia sclerotiorum resistance in Brassica napus.

Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum (Lib.) De Bary is a devastating disease infecting hundreds of plant species. It also restricts the yield, quality, and safe production of rapeseed (Brassica napus) worldwide. However, the lack of resistance sources and genes to S. sclerotiorum has greatly restricted rapeseed SSR-resistance breeding. In this study, a previously identified GDSL motif-containing lipase gene, Brassica napus GDSL LIPASE-LIKE 1 (BnaC07.GLIP1), encoding a protein localized to the intercellular space, was characterized as functioning in plant immunity to S. sclerotiorum. The BnaC07.GLIP1 promoter is S. sclerotiorum-inducible and the expression of BnaC07.GLIP1 is substantially enhanced after S. sclerotiorum infection. Arabidopsis (Arabidopsis thaliana) heterologously expressing and rapeseed lines overexpressing BnaC07.GLIP1 showed enhanced resistance to S. sclerotiorum, whereas RNAi suppression and CRISPR/Cas9 knockout B. napus lines were hyper-susceptible to S. sclerotiorum. Moreover, BnaC07.GLIP1 affected the lipid composition and induced the production of phospholipid molecules, such as phosphatidylethanolamine, phosphatidylcholine and phosphatidic acid, which were correlated with decreased levels of reactive oxygen species (ROS) and enhanced expression of defense-related genes. A B. napus bZIP44 transcription factor specifically binds the CGTCA motif of the BnaC07.GLIP1 promoter to positively regulate its expression. BnbZIP44 responded to S. sclerotiorum infection, and its heterologous expression inhibited ROS accumulation, thereby enhancing S. sclerotiorum resistance in Arabidopsis. Thus, BnaC07.GLIP1 functions downstream of BnbZIP44 and is involved in S. sclerotiorum resistance by modulating the production of phospholipid molecules and ROS homeostasis in B. napus, providing insights into the potential roles and functional mechanisms of BnaC07.GLIP1 in plant immunity and for improving rapeseed SSR disease-resistance breeding.

Site-Selective Biofunctionalization of 3D Microstructures Via Direct Ink Writing.

Two-photon lithography has revolutionized multi-photon 3D laser printing, enabling precise fabrication of micro- and nanoscale structures. Despite many advancements, challenges still persist, particularly in biofunctionalization of 3D microstructures. This study introduces a novel approach combining two-photon lithography with scanning probe lithography for post-functionalization of 3D microstructures overcoming limitations in achieving spatially controlled biomolecule distribution. The method utilizes a diverse range of biomolecule inks, including phospholipids, and two different proteins, introducing high spatial resolution and distinct functionalization on separate areas of the same microstructure. The surfaces of 3D microstructures are treated using bovine serum albumin and/or 3-(Glycidyloxypropyl)trimethoxysilane (GPTMS) to enhance ink retention. The study further demonstrates different strategies to create binding sites for cells by integrating different biomolecules, showcasing the potential for customized 3D cell microenvironments. Specific cell adhesion onto functionalized 3D microscaffolds is demonstrated, which paves the way for diverse applications in tissue engineering, biointerfacing with electronic devices and biomimetic modeling.

De Novo Synthesis of Perdeuterated Phosphoinositide by Installing a Non-native Phospholipid Biopathway in E. coli.

Phosphatidylinositol (PI) and its phosphorylated derivatives are of paramount importance in cellular functions and diseases. Understanding their diverse roles is, however, challenged by difficulties in synthesis and labeling techniques. In this proof-of-concept study, we demonstrate that PI can be straightforwardly de novo-synthesized and deuterium (2H)-labeled in Escherichia coli by genomic insertion of PI synthase from Trypanosoma brucei under constitutive synthetic promoter proD. Insertion into loci atpi-gidB and ybb revealed PI accumulation of 41% and 34% (mol/mol), respectively, when cultivated with glycerol as the sole carbon source. Growth of the atpi-gidB-PIS strain in deuterium-labeled (2H) substrates D2O, D8-glycerol, and D6-myo-inositol achieved PI deuteration of 90%, PE deuteration of 95%, and total fatty acids|fatty acid (FA) deuteration of 97%. This study offers an alternative convenient route to chemical and enzymatic labeling synthesis of PI; more excitingly, this work also, in principle, opens a door for tailoring the FA profile of deuterated PI/PE for task-specific application by repurposing FA biosynthesis pathways.

Thermodynamic Study on Biomimetic Legionella gormanii Bacterial Membranes.

The presented studies were aimed at determining the interactions in model membranes (Langmuir monolayers) created of phospholipids (PL) isolated from Legionella gormanii bacteria cultured with (PL + choline) or without (PL - choline) choline and to describe the impact of an antimicrobial peptide, human cathelicidin LL-37, on PL's monolayer behavior. The addition of choline to the growth medium influenced the mutual proportions of phospholipids extracted from L. gormanii. Four classes of phospholipids-phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), cardiolipin (CL), and their mixtures-were used to register compression isotherms with or without the LL-37 peptide in the subphase. Based on them the excess area (Ae), excess (ΔGe), and total (ΔGm) Gibbs energy of mixing were determined. The thermodynamic analyses revealed that the PL - choline monolayer showed greater repulsive forces between molecules in comparison to the ideal system, while the PL + choline monolayer was characterized by greater attraction. The LL-37 peptide affected the strength of interactions between phospholipids' molecules and reduced the monolayers stability. Accordingly, the changes in interactions in the model membranes allowed us to determine the difference in their susceptibility to the LL-37 peptide depending on the choline supplementation of bacterial culture.

Phospholipid-derived lysophospholipids in (patho)physiology.

Phospholipids (PL) are major components of cellular membranes and changes in PL metabolism have been associated with the pathogenesis of numerous diseases. Lysophosphatidylcholine (LPC) in particular, is a comparably abundant component of oxidatively damaged tissues. LPC originates from the cleavage of phosphatidylcholine (PC) by phospholipase A2 or the reaction of lipids with reactive oxygen species (ROS) such as HOCl. Another explanation of increased LPC concentration is the decreased re-acylation of LPC into PC. While there are also several other lysophospholipids, LPC is the most abundant lysophospholipid in mammals and will therefore be the focus of this review. LPC is involved in many physiological processes. It induces the migration of lymphocytes, fostering the production of pro-inflammatory compounds by inducing oxidative stress. LPC also "signals" via G protein-coupled and Toll-like receptors and has been implicated in the development of different diseases. However, LPCs are not purely "bad": this is reflected by the fact that the concentration and fatty acyl composition of LPC varies under different conditions, in plasma of healthy and diseased individuals, in tissues and different tumors. Targeting LPC and lipid metabolism and restoring homeostasis might be a potential therapeutic method for inflammation-related diseases.

Lipidomic analyses reveal distinctive variations in homeoviscous adaptation among clinical strains of Acinetobacter baumannii, providing insights from an environmental adaptation perspective.

Acinetobacter baumannii is known for its antibiotic resistance and is increasingly found outside of healthcare settings. To survive colder temperatures, bacteria, including A. baumannii, adapt by modifying glycerophospholipids (GPL) to maintain membrane flexibility. This study examines the lipid composition of six clinical A. baumannii strains, including the virulent AB5075, at two temperatures. At 18°C, five strains consistently show an increase in palmitoleic acid (C16:1), while ABVal2 uniquely shows an increase in oleic acid (C18:1). LC-HRMS2 analysis identifies shifts in GPL and glycerolipid composition between 18°C and 37°C, highlighting variations in phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) lipids. ABVal2 shows increased PE with C18:1 and C16:1 at 18°C, but no change in PG, in contrast to other strains that show increased PE and PG with C16:1. Notably, although A. baumannii typically lacks FabA, a key enzyme for unsaturated fatty acid synthesis, this enzyme was found in both ABVal2 and ABVal3. In addition, ABVal2 contains five candidate desaturases that may contribute to its lipid profile. The study also reveals variations in strain motility and biofilm formation over temperature. These findings enhance our understanding of A. baumannii's physiological adaptations, survival strategies and ecological fitness in different environments.IMPORTANCEAcinetobacter baumannii, a bacterium known for its resistance to antibiotics, is a concern in healthcare settings. This study focused on understanding how this bacterium adapts to different temperatures and how its lipid composition changes. Lipids are the building blocks of cell membranes. By studying these changes, scientists can gain insights into how the bacterium survives and behaves in various environments. This understanding improves our understanding of its global dissemination capabilities. The results of the study contribute to our broader understanding of how Acinetobacter baumannii works, which is important for developing strategies to combat its impact on patient health.

Unveiling the neurolipidome of obsessive-compulsive disorder: A scoping review navigating future diagnostic and therapeutic applications.

Obsessive-Compulsive Disorder (OCD) poses a multifaceted challenge in psychiatry, with various subtypes and severities greatly impacting well-being. Recent scientific attention has turned towards lipid metabolism, particularly the neurolipidome, in response to clinical demands for cost-effective diagnostics and therapies. This scoping review integrates recent animal, translational, and clinical studies to explore impaired neurolipid metabolism mechanisms in OCD's pathogenesis, aiming to enhance future diagnostics and therapeutics. Five key neurolipids - endocannabinoids, lipid peroxidation, phospholipids, cholesterol, and fatty acids - were identified as relevant. While the endocannabinoid system shows promise in animal models, its clinical application remains limited. Conversely, lipid peroxidation and disruptions in phospholipid metabolism exhibit significant impacts on OCD's pathophysiology based on robust clinical data. However, the role of cholesterol and fatty acids remains inconclusive. The review emphasises the importance of translational research in linking preclinical findings to real-world applications, highlighting the potential of the neurolipidome as a potential biomarker for OCD detection and monitoring. Further research is essential for advancing OCD understanding and treatment modalities.

Metabolomics study of serum from patients with type 2 diabetes: Peripheral neuropathy could be associated with sphingosine and phospholipid molecules.

Abnormal lipid metabolism is one of the risk factors for type 2 diabetes mellitus peripheral neuropathy (DPN). This study aimed to determine the differences in lipid metabolism in patients with type 2 diabetes and DPN and the possible pathogenesis caused by this difference. The participants comprised type 2 diabetes mellitus patients with DPN (N = 60) and healthy controls (N = 20). Blood samples were drawn from the participants in the morning in the fasting state, and then changes in serum lipids were explored using targeted metabolomics on the liquid chromatography-electrospray ionization-tandem mass spectrometry platform. Among the 1768 differentially abundant lipid metabolites, the results of orthogonal partial least squares-discriminant analysis combined with random forest analysis showed that the levels of sphingosine (SPH) (d18:0), carnitine 22:1, lysophosphatidylethanolamine (LPE) (18:0/0:0), LPC (16:0/0:0), lysophosphatidylcholine (LPC) (18:1/0:0), LPC (0:0/18:0) and LPE (0:0/18:1) were significantly different between the two groups. Spearman correlation analysis showed that SPH (d18:0), carnitine 22:1, LPE (18:0/0:0), and LPC (0:0/18:0) levels correlated highly with the patients' electromyography results. Kyoto Encyclopedia of Genes and Genomes pathway annotation and enrichment analysis of 538 differentially abundant lipid metabolites revealed that type 2 diabetes mellitus DPN was related to glycerophospholipid metabolism and glycerol metabolism. Our results further identified the dangerous lipid metabolites associated with DPN and abnormal lipid metabolism. The influence of lipid metabolites such as SPH and phospholipid molecules on DPN development in patients with type 2 diabetes mellitus were suggested and the possible pathogenic pathways were clarified, providing new insights into the clinical risk of DPN in patients with type 2 diabetes mellitus.

A novel strategy of bloom forming cyanobacteria Microcystis sp. in response to phosphorus deficiency: Using non-phosphorus lipids substitute phospholipids.

Despite significant reductions in phosphorus (P) loads, lakes still experience cyanobacterial blooms. Little is known regarding cellular P regulation in response to P deficiency in widely distributed bloom causing species such as Microcystis. In this study, we investigated changes in P containing and non-P lipids contents and their ratios concomitantly with the determinations of expression levels of genes encoding these lipids in cultural and field Microcystis samples. In the culture, the content of phosphatidylglycerol (PG) decreased from 2.1 µg g-1 in P replete control to 1.2 µg g-1 in P-deficient treatment, while non-P lipids, like sulfoquinovosyldiacylglycerol (SQDG) and monogalactosyldiacylglycerol (MGDG), increased dramatically from 13.6 µg g-1 to 142.3 µg g-1, and from 0.9 µg g-1 to 16.74 µg g-1, respectively. The expression of the MGDG synthesis gene, mgdE, also increased under low P conditions. Significant positive relationships between soluble reactive phosphorus (SRP) and ratios of P-containing lipids (PG) to non-P lipids, including SQDG, MGDG and digalactosyldiacylglycerol (DGDG) (P < 0.05) were observed in the field investigations. Both cultural and field data indicated that Microcystis sp. might increase non-P lipids proportion to lower P demand when suffering from P deficiency. Furthermore, despite lipid remodeling, photosynthetic activity remained stable, as indicated by comparable chlorophyll fluorescence and Fv/Fm ratios among cultural treatments. These findings suggested that Microcystis sp. may dominate in P-limited environments by substituting glycolipids and sulfolipids for phospholipids to reduce P demand without compromising the photosynthetic activity. This effective strategy in response to P deficiency meant a stricter P reduction threshold is needed in terms of Microcystis bloom control.

Milk Fat Globule Membrane Is Associated with Lower Blood Lipid Levels in Adults: A Meta-Analysis of Randomized Controlled Trials.

Cardiovascular diseases (CVDs) are the leading cause of mortality worldwide, with dyslipidemia being a significant risk factor. This meta-analysis provides a comprehensive evaluation of the impact of bovine dairy-derived milk fat globule membrane (MFGM) supplementation on blood lipid profiles in adults. A systematic search was conducted across various databases up until March 2024, resulting in the inclusion of 6 trials with a total of 464 participants. The findings indicated that MFGM phospholipid supplementation may significantly reduce total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol levels. A combined analysis of the effects on TC, LDL, and triglycerides (TG) revealed a significant overall reduction in these markers. However, no significant increase or reduction was observed on high-density lipoprotein (HDL) and TG levels. Overall, MFGM phospholipid intake may significantly decrease the level of TC and LDL, while no significant changes in TG and HDL were observed. These results suggest that MFGM supplementation could be a promising dietary intervention for improving lipid profiles in adults. Nonetheless, further research is warranted to confirm these results and to better understand the potential variability in the impact of MFGM on blood lipid levels.

LC-HRMS analysis of phospholipids bearing oxylipins.

BACKGROUND: Several oxylipins including hydroxy- and epoxy-polyunsaturated fatty acids act as lipid mediators. In biological samples they can be present as non-esterified form, but the major part occurs esterified in phospholipids (PL) or other lipids. Esterified oxylipins are quantified indirectly after alkaline hydrolysis as non-esterified oxylipins. However, in this indirect analysis the information in which lipid class oxylipins are bound is lost. In this work, an untargeted liquid chromatography high-resolution mass spectrometry (LC-HRMS) method for the direct analysis of PL bearing oxylipins was developed. RESULTS: Optimized reversed-phase LC separation achieved a sufficient separation of isobaric and isomeric PL from different lipid classes bearing oxylipin positional isomers. Individual PL species bearing oxylipins were identified based on retention time, precursor ion and characteristic product ions. The bound oxylipin could be characterized based on product ions resulting from the α-cleavage occurring at the hydroxy/epoxy group. PL sn-1/sn-2 isomers were identified based on the neutral loss of the fatty acyl in the sn-2 position. A total of 422 individual oxPL species from 7 different lipid classes i.e., PI, PS, PC, PE, PC-P, PC-O, and PE-P were detected in human serum and cells. This method enabled to determine in which PL class supplemented oxylipins are incorporated in HEK293 cells: 20:4;15OH, 20:4;14Ep, and 20:5;14Ep were mostly bound to PI. 20:4;8Ep and 20:5;8Ep were esterified to PC and PE while other oxylipins were mainly found in PC. SIGNIFICANCE: The developed LC-HRMS method enables the comprehensive detection as well as the semi-quantification of isobaric and isomeric PL species bearing oxylipins. With this method, we show that the position of the oxidation has a great impact and directs the incorporation of oxylipins into the different PL classes in human cells.

Setting the curve: the biophysical properties of lipids in mitochondrial form and function.

Mitochondrial membranes are defined by their diverse functions, complex geometries, and unique lipidomes. In the inner mitochondrial membrane (IMM), highly-curved membrane folds known as cristae house the electron transport chain and are the primary sites of cellular energy production. The outer mitochondrial membrane (OMM) is flat by contrast, but is critical for the initiation and mediation of processes key to mitochondrial physiology: mitophagy, inter-organelle contacts, fission and fusion dynamics and metabolite transport. While the lipid composition of both the IMM and OMM have been characterized across a variety of cell types, a mechanistic understanding for how individual lipid classes contribute to mitochondrial structure and function remains nebulous. In this review, we address the biophysical properties of mitochondrial lipids and their related functional roles. We highlight the intrinsic curvature of the bulk mitochondrial phospholipid pool, with an emphasis on the nuances surrounding the mitochondrially-synthesized cardiolipin. We also outline emerging questions about other lipid classes, ether lipids and sterols, with potential roles in mitochondrial physiology. We propose that further investigation is warranted to elucidate the specific properties of these lipids and their influence on mitochondrial architecture and function.

Lack of Arabidopsis chloroplastic glucose-6-phosphate dehydrogenase 1 (G6PD1) affects lipid synthesis during cold stress response.

Cold stress represents one of the major constraints for agricultural systems and crops productivity, inducing a wide range of negative effects. Particularly, long-term cold stress affects lipid metabolism, modifying the lipids/proteins ratio, the levels of phospholipids and glycolipids, and increasing lipids' unsaturation in bio-membranes. Glucose-6-phosphate dehydrogenase (G6PDH) reported prominent roles as NADPH suppliers in response to oxidative perturbations. Cytosolic G6PDH was suggested as the main isoform involved in cold stress response, while a down-regulation of the chloroplastic P1-G6PDH was observed. We thus investigated an Arabidopsis mutant defective for the P1-G6PDH (KO-P1) using integrated approaches to verify a possible role of this isoform in low temperature tolerance. KO-P1 genotype showed an improved tolerance to cold stress, highlighting a better photosynthetic efficiency, a reduction in stress markers content and a different regulation of genes involved in stress response. Intriguingly, the lack of P1-G6PDH induced modification in the levels of the main fatty acid and lipid species affecting the morphology of chloroplasts and mitochondria, which was restored under cold. Globally, these results indicate a priming effect induced by the absence of P1-G6PDH able to improve the tolerance to abiotic stress. Our results suggest novel and specific abilities of P1-G6PDH, highlighting its central role in different aspects of plant physiology and metabolism.

The Role of Serum Albumin and Secretory Phospholipase A2 in Sepsis.

Sepsis is caused by a dysregulated host response to an infection that leads to cascading cell death and eventually organ failure. In this study, the role of inflammatory response serum secretory phospholipase A2 (sPLA2) and albumin in sepsis was investigated by determining the activities of the two proteins in serial serum samples collected on different days from patients with sepsis after enrollment in the permissive underfeeding versus standard enteral feeding protocols in an intensive care unit. Serum sPLA2 and albumin showed an inverse relationship with increasing sPLA2 activity and decreasing albumin membrane-binding activity in patients with evolving complications of sepsis. The activities of sPLA2 and albumin returned to normal values more rapidly in the permissive underfeeding group than in the standard enteral feeding group. The inverse sPLA2-albumin activity relationship suggests a complex interplay between these two proteins and a regulatory mechanism underlying cell membrane phospholipid homeostasis in sepsis. The decreased albumin-membrane binding activity in patients' serum was due to its fatty acid-binding sites occupied by pre-bound fatty acids that might alter albumin's structure, binding capacities, and essential functions. The sPLA2-albumin dual serum assays may be useful in determining whether nutritional intervention effectively supports the more rapid recovery of appropriate immune responses in critically ill patients with sepsis.

Dynamic Membrane Lipid Changes in Physcomitrium patens Reveal Developmental and Environmental Adaptations.

Membrane lipid composition is critical for an organism's growth, adaptation, and functionality. Mosses, as early non-vascular land colonizers, show significant adaptations and changes, but their dynamic membrane lipid alterations remain unexplored. Here, we investigated the temporal changes in membrane lipid composition of the moss Physcomitrium patens during five developmental stages and analyzed the acyl content and composition of the lipids. We observed a gradual decrease in total lipid content from the filamentous protonema stage to the reproductive sporophytes. Notably, we found significant levels of very long-chain polyunsaturated fatty acids, particularly arachidonic acid (C20:4), which are not reported in vascular plants and may aid mosses in cold and abiotic stress adaptation. During vegetative stages, we noted high levels of galactolipids, especially monogalactosyldiacylglycerol, associated with chloroplast biogenesis. In contrast, sporophytes displayed reduced galactolipids and elevated phosphatidylcholine and phosphatidic acid, which are linked to membrane integrity and environmental stress protection. Additionally, we observed a gradual decline in the average double bond index across all lipid classes from the protonema stage to the gametophyte stage. Overall, our findings highlight the dynamic nature of membrane lipid composition during moss development, which might contribute to its adaptation to diverse growth conditions, reproductive processes, and environmental challenges.

Three separate pathways in Rhizobium leguminosarum maintain phosphatidylcholine biosynthesis, which is required for symbiotic nitrogen fixation with clover.

Phosphatidylcholine (PC) is critical for the nitrogen-fixing symbiosis between rhizobia and legumes. We characterized three PC biosynthesis pathways in Rhizobium leguminosarum and evaluated their impact on nitrogen fixation in clover nodules. In the presence of choline, a PC synthase catalyzes the condensation of cytidine diphosphate-diacylglycerol with choline to produce PC. In the presence of lyso-PC, acyltransferases acylate this mono-acylated phospholipid to PC. The third pathway relies on phospholipid N-methyltransferases (Pmts), which sequentially methylate phosphatidylethanolamine (PE) through three rounds of methylation, yielding PC via the intermediates monomethyl-PE and dimethyl-PE. In R. leguminosarum, at least three Pmts participate in this methylation cascade. To elucidate the functions of these enzymes, we recombinantly produced and biochemically characterized them. We moved on to determine the phospholipid profiles of R. leguminosarum mutant strains harboring single and combinatorial deletions of PC biosynthesis genes. The cumulative results show that PC production occurs through the combined action of multiple enzymes, each with distinct substrate and product specificities. The methylation pathway emerges as the dominant PC biosynthesis route, and we pinpoint PmtS2, which catalyzes all three methylation steps, as the enzyme responsible for providing adequate PC amounts for a functional nitrogen-fixing symbiosis with clover. IMPORTANCE: Understanding the molecular mechanisms of symbiotic nitrogen fixation has important implications for sustainable agriculture. The presence of the phospholipid phosphatidylcholine (PC) in the membrane of rhizobia is critical for the establishment of productive nitrogen-fixing root nodules on legume plants. The reasons for the PC requirement are unknown. Here, we employed Rhizobium leguminosarum and clover as model system for a beneficial plant-microbe interaction. We found that R. leguminosarum produces PC by three distinct pathways. The relative contribution of these pathways to PC formation was determined in an array of single, double, and triple mutant strains. Several of the PC biosynthesis enzymes were purified and biochemically characterized. Most importantly, we demonstrated the essential role of PC formation by R. leguminosarum in nitrogen fixation and pinpointed a specific enzyme indispensable for plant-microbe interaction. Our study offers profound insights into bacterial PC biosynthesis and its pivotal role in biological nitrogen fixation.

The sphingosine kinase 2 inhibitors ABC294640 and K145 elevate (dihydro)sphingosine 1-phosphate levels in various cells.

Sphingosine kinases (SphKs), enzymes that produce the bioactive lipids dihydrosphingosine 1-phosphate (dhS1P) and sphingosine 1-phosphate (S1P), are associated with various diseases, including cancer and infections. For this reason, a number of SphK inhibitors have been developed. Although off-target effects have been described for selected agents, SphK inhibitors are mostly used in research without monitoring the effects on the sphingolipidome. We have now investigated the effects of seven commonly used SphK inhibitors (5c, ABC294640 (opaganib), N,N-dimethylsphingosine, K145, PF-543, SLM6031434, and SKI-II) on profiles of selected sphingolipids in Chang, HepG2, and human umbilical vein endothelial cells. While we observed the expected (dh)S1P reduction for N,N-dimethylsphingosine, PF-543, SKI-II, and SLM6031434, 5c showed hardly any effect. Remarkably, for K145 and ABC294640, both reported to be specific for SphK2, we observed dose-dependent strong increases in dhS1P and S1P across cell lines. Compensatory effects of SphK1 could be excluded, as this observation was also made in SphK1-deficient HK-2 cells. Furthermore, we observed effects on dihydroceramide desaturase activity for all inhibitors tested, as has been previously noted for ABC294640 and SKI-II. In additional mechanistic studies, we investigated the massive increase of dhS1P and S1P after short-term cell treatment with ABC294640 and K145 in more detail. We found that both compounds affect sphingolipid de novo synthesis, with 3-ketodihydrosphingosine reductase and dihydroceramide desaturase as their targets. Our study indicates that none of the seven SphK inhibitors tested was free of unexpected on-target and/or off-target effects. Therefore, it is important to monitor cellular sphingolipid profiles when SphK inhibitors are used in mechanistic studies.

Insight into the effects of large yellow croaker roe (Larimichthys Crocea) phospholipids on the conformational and functional properties of pork myofibrillar protein.

The large yellow croaker roe phospholipids (LYPLs), rich in polyunsaturated fatty acids, is a potential phospholipid additive for meat products. In this work, the effects of LYPLs on the structural and functional properties of myofibrillar protein (MP) were determined, and compared with egg yolk phospholipids (EYPLs) and soybean phospholipids (SBPLs). The results revealed that LYPLs, similar to SBPLs and EYPLs, induced a transformation in the secondary structure of MP from α-helix to ß-sheets and random coils, while also inhibited the formation of carbonyl and disulfide bonds within MP. All three phospholipids induced MP tertiary structure unfolding, with the greatest degree of unfolding observed in MP containing LYPLs. The MP with LYPLs had the highest surface hydrophobicity, emulsification properties and gel strength. In addition, MP with LYPLs added also demonstrated superior rheological properties and water-holding capacity compared with SBPLs and EYPLs. In conclusion, adding LYPLs endowed MP with improved functional properties.

A lipidomic and volatilomic approach to map the lipid profile and related volatile compounds in roasted quail meat using circulating non-fried roast technology.

Lipids play a significant role in aroma formation. However, lipid variations and their impact on aroma during the processing of quail meat remain unknown. Therefore, a comprehensive analysis of lipids and aroma compounds was conducted in circulating non-fried roasted quail meat. Nineteen odorants were identified as key aroma compounds in the roasted quail meat at 40 min with OAVs of >1. The concentrations of most key odorants significantly increased in circulating non-fried roasted (CNR) quail meat within the first 30 min of roasting, reaching maximum values at 40 min. Phospholipids, neutral lipids, and sphingolipids emerged as potential markers for distinguishing different samples. Neutral lipids had the highest peak areas and significantly contributed to the aroma retention. Phospholipids and neutral lipids with unsaturated fatty acids, particularly C18 acyl groups, played a crucial role in aroma formation. This study provides valuable insights into the role of lipids in determining aroma quality.

Dietary modulation of lung lipids influences inflammatory responses to inhaled ozone.

The pulmonary system represents a unique lipidomic environment as it contains cellular membrane-bound lipid species and a specialized reservoir of lipids in the airway epithelial lining fluid. As a major initial point of defense, airway lipids react to inhaled contaminants such as volatile organic compounds, oxides of nitrogen, or ozone (O3), creating lipokine signaling that is crucial for both the initiation and resolution of inflammation within the lung. Dietary modulation of eicosanoids has gained increased attention in recent years for improvements to cardiovascular health. The current study sought to examine how dietary supplementation with eicosanoid precursors (i.e, oils rich in saturated or polyunsaturated fatty acids) might alter the lung lipid composition and subsequently modify the inflammatory response to ozone inhalation. Our study demonstrated that mice fed a diet high in saturated fatty acids resulted in diet-specific changes to lung lipid profiles and increased cellular recruitment to the lung following ozone inhalation. Bioinformatic analysis revealed an ozone-dependent upregulation of several lipid species, including phosphoserine 37:5. Pathway analysis of lipid species revealed the process of lateral diffusion of lipids within membranes to be significantly altered due to ozone exposure. These results show promising data for influencing pulmonary lipidomic profiles via diet, which may provide a pragmatic therapeutic approach to protect against lung inflammation and damage following pulmonary insult.