Search Results (30)

Microalgae of the genus Nannochloropsis are known for their ability to accumulate large amounts of lipids, particularly triacylglycerides (TAGs), when exposed to nitrogen-limiting conditions. This trait makes them promising candidates for biofuel production. While previous studies have used transcriptomics and metabolomics to explore how these organisms respond to nutrient stress, the role of post-translational modifications—especially protein phosphorylation—remains poorly understood. To address this gap, we conducted a comprehensive analysis of protein phosphorylation events in Nannochloropsis oceanica under both nitrogen-replete and nitrogen-depleted conditions over a time-course experiment. Using mass spectrometry-based phosphoproteomics, we identified 1371 phosphorylation sites across 884 proteins. Temporal clustering of these phosphorylation events revealed two distinct regulatory phases: an early response aimed at conserving nitrogen resources, and a later phase that promotes lipid accumulation. Notably, we identified 11 phosphorylated proteins associated with the Target of Rapamycin (TOR) signaling pathway, suggesting that this conserved regulatory network plays a key role in coordinating the cellular response to nitrogen deficiency. By integrating our phosphoproteomic result with previously published transcriptomic and metabolomic datasets, we provide a more complete view of how N. oceanica adapts to nitrogen stress at the molecular level. This systems-level approach highlights the importance of protein phosphorylation in regulating metabolic shifts and offers new insights into engineering strategies for enhancing lipid production in microalgae. Full article

Background/Objectives: Metabolic dysfunction-associated steatotic liver disease (MASLD) is a sexually dimorphic condition, with higher prevalence in men than in women. Sex differences in hepatic lipid metabolism and the modulatory role of sex hormones have been described but are still insufficiently understood. The aim of this study was to introduce the variables sex and sex hormones into a human in vitro model of hepatic steatosis. Methods: Primary human hepatocytes (PHHs) were isolated from male and female donors, treated with free fatty acids (FFA) to induce steatosis, and further exposed to physiological concentrations of estrogen, progesterone, or testosterone. Intracellular triacylglyceride (TAG) content, lipid droplet (LD) formation, FFA uptake, and very-low-density lipoprotein (VLDL) excretion were assessed. In parallel, the expression of lipid metabolism-related genes was quantified by qPCR. Results: FFA treatment induced comparable uptake and intracellular TAG storage in both sexes. However, female PHHs secreted approximately twice as many VLDL particles as male cells. Steatosis significantly increased expression of LDLR, CPT2, and PLA1A only in male PHHs. Sex hormones exerted distinct, sex-specific effects: estrogen reduced TAG accumulation in female PHHs; whereas testosterone reduced TAG in male but increased it in female PHHs after prolonged treatment. LD characterization confirmed sex- and hormone-dependent differences in lipid storage patterns. In male PHHs, progesterone promoted lipid storage and increased apoB-100 secretion, accompanied by reduced LDLR and APOA5 expression, and testosterone increased the FFA-mediated CPT2 even further. Conclusions: Sex and sex hormones distinctly shape hepatocellular lipid handling under steatotic conditions. While female PHHs demonstrated greater lipid excretion capacity, male PHHs exhibited stronger transcriptional responses. Sex-specific responses to estrogen and testosterone resembled clinical observations on sex hormone effects. These findings highlight the need to account for sex-specific differences in MASLD pathophysiology and therapeutic strategies. Full article

The aim of this study was to investigate the combined effects of temperature and light on the photosynthetic parameters and lipid accumulation in the diatom Phaeodactylum tricornutum, a model organism widely used for studies on diatom physiology, ecology, and biotechnology. Our results highlight the importance of the interaction between temperature and light intensity in influencing growth rates, pigments and active photosystems content, photosynthetic efficiency, lipid production and fatty acid composition in P. tricornutum. Measurements of the maximum electron transport rate (rETR_max) and rETR at maximum PAR (830 µmol m⁻² s⁻¹) confirmed that P. tricornutum exhibits significantly higher light sensitivity as growth temperature increases under light/dark cycles at two light intensities (25–60 µmol m⁻² s⁻¹). However, this trend was reversed under continuous light (25 µmol m⁻² s⁻¹). Moreover, higher rETR_max values (up to double) were observed at higher irradiance, either in intensity or under continuous light regimes, at the two temperatures tested. On the other hand, increasing light intensity amplified the observed effect of temperature on photosystem I (PSI) activity under light/dark regimes, but not under continuous light conditions. This resulted in a greater deficiency in PSI activity, likely due to limitations in electron supply to this photosystem. Furthermore, increasing the culture temperature from 20 °C to 25 °C triggered an increase in the number and size of cytoplasmic lipid droplets under conditions of increased light intensity, with an even more pronounced effect under continuous illumination. Notably, the combination of 25 °C and continuous illumination resulted in a more than twofold increase in triacylglyceride (TAG) content, reaching approximately 17 mg L⁻¹. This condition also caused a substantial rise (up to ≈90%) in the proportions of palmitoleic and palmitic acids in the TAG fatty acid profile. Full article

Triacylglycerides (TAGs) produced via the syngas fermentation of biogenic residues and wastes were evaluated as a potential feedstock for advanced road transportation, aviation, and maritime drop-in fuels via hydroprocessing technology. Due to the limited availability of TAGs, a simulated feedstock (SM TAGs) was utilized by blending various commercial oils, simulating the fatty acid composition of TAGs. At first, the simulated feedstock and the real TAGs were hydrotreated on a TRL 4 (technology readiness level) pilot plant to evaluate the potential of the SM feedstock to simulate the TAGs based on product quality. The hydrotreatment technology was evaluated and optimized on a TRL 4 plant. The research was further extended to a TRL 5 hydrotreatment plant with the optimum operating window for scaling up the technology. The resulting product was fractionated on a batch fractionation unit under vacuum to separate the jet and diesel fractions. The produced fuels were analyzed and evaluated based on the aviation Jet A1, EN590, EN15940, and marine diesel DMA specifications. The results show that the TAG composition was successfully simulated via a blend of vegetable oils. In addition, the hydrotreatment of the real TAGs and simulated feedstock resulted in similar-quality liquid products. The technology was successfully scaled up on a TRL 5 unit, leading to advanced, high-quality aviation and diesel drop-in fuels from TAGs, while the reaction pathways of hydrotreating can be controlled via the operating parameters of pressure, temperature, and H₂/oil ratio. The hydrotreatment process’s optimum conditions were 13.8 MPa pressure, 643 K temperature, 1 h⁻¹ liquid hourly space velocity (LHSV), and 5000 scfb hydrogen-to-oil ratio. Finally, a storage stability study of the hydrotreated liquid product showed that it can be stored for more than 6 months at ambient conditions without any noticeable changes to its properties. Full article

In the recent past, various microalgae have been considered a renewable energy source for biofuel production, and their amount and extent can be enhanced by applying certain types of stress including salinity. Although microalgae growing under salinity stress result in a higher lipid content, they simultaneously reduce in growth and biomass output. To resolve this issue, the physiochemical changes in microalgae Scenedesmus sp. BHU1 have been assessed through two-stage cultivation. In stage-I, the maximum carbohydrate and lipid contents (39.55 and 34.10%) were found at a 0.4 M NaCl concentration, while in stage-II, the maximum carbohydrate and lipid contents (42.16 and 38.10%) were obtained in the 8-day-old culture. However, under increased salinity, Scenedesmus sp. BHU1 exhibited a decrease in photosynthetic attributes, including Chl-a, Chl-b, Fv/Fm, Y(II), Y(NPQ), NPQ, qP, qL, qN, and ETRmax but increased Y(NO) and carotenoids content. Apart from physiological attributes, osmoprotectants, stress biomarkers, and nonenzymatic antioxidants were also studied to elucidate the role of reactive oxygen species (ROS) facilitated lipid synthesis. Furthermore, elemental and mineral ion analysis of microalgal biomass was performed to evaluate the biomass quality for biofuel and cell homeostasis. Based on fluorometry analysis, we found the maximum neutral lipids in the 8-day-old grown culture at stage-II in Scenedesmus sp. BHU1. Furthermore, the use of Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy analyses confirmed the presence of higher levels of hydrocarbons and triacylglycerides (TAGs) composed of saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) in the 8-day-old culture. Therefore, Scenedesmus sp. BHU1 can be a promising microalga for potential biodiesel feedstock. Full article

Acid sphingomyelinase deficiency (ASMD) or Niemann–Pick disease type A (NPA), type B (NPB) and type A/B (NPA/B), is a rare lysosomal storage disease characterized by progressive accumulation of sphingomyelin (SM) in the liver, lungs, bone marrow and, in severe cases, neurons. A disease model was established by generating liver organoids from a NPB patient carrying the p.Arg610del variant in the SMPD1 gene. Liver organoids were characterized by transcriptomic and lipidomic analysis. We observed altered lipid homeostasis in the patient-derived organoids showing the predictable increase in sphingomyelin (SM), together with cholesterol esters (CE) and triacylglycerides (TAG), and a reduction in phosphatidylcholine (PC) and cardiolipins (CL). Analysis of lysosomal gene expression pointed to 24 downregulated genes, including SMPD1, and 26 upregulated genes that reflect the lysosomal stress typical of the disease. Altered genes revealed reduced expression of enzymes that could be involved in the accumulation in the hepatocytes of sphyngoglycolipids and glycoproteins, as well as upregulated genes coding for different glycosidases and cathepsins. Lipidic and transcriptome changes support the use of hepatic organoids as ideal models for ASMD investigation. Full article

Certain limitations exist for animals to modify fatty acid changes. Besides the role of arachidonic acid (AA), docosahexaenoic acid (DHA) and other 20-carbon long-chain polyunsaturated fatty acids (LCPUFAs) for the synthesis of inflammatory mediators as eicosanoids, different LCPUFAs have many other effects, including their abilities to regulate gene expression and downstream events. LCPUFAs are susceptible to autoxidation, which is prevented by the action of antioxidants in the form of enzymes like superoxide dismutases, catalases and peroxidases, as well as antioxidant compounds that protect against oxidation or repair the damage caused. Under normal conditions, the fetus needs both essential fatty acids (EFAs) and LCPUFAs, which are obtained from its mother by placental transfer. In early pregnancy, dietary derived fatty acids are accumulated in maternal adipose tissue. However, during late pregnancy, corresponding to the period of the highest fetal growth, maternal adipose tissue becomes catabolic and LCPUFAs are released into the circulation by adipose lipolytic activity. The released LCPUFAs are taken up by maternal liver to be esterified and released back to the circulation as triacylglycerides (TAGs) in very-low-density lipoprotein (VLDL) that become available to the placenta to be transferred to the fetus in the form of non-esterified fatty acids (NEFAs). An enhanced adipose tissue lipolysis is maintained around parturition and esterified LCPUFAs are diverted to mammary glands thanks to an increased activity of lipoprotein lipase for milk production. Throughout this process, LCPUFAs become available to the newborn during suckling. The important role of both DHA and AA for the development of the nervous system and for growth has motivated their dietary supplement during different postnatal stages. This has been especially important in preterm infants both because under normal conditions, the fetus acquires most of these fatty acids during late pregnancy, and because the immaturity of the enzyme systems for the synthesis of AA and DHA from their respective EFAs. Full article

Oleaginous red yeast species are colourful (usually having orange-pink-red hues) single cell microorganisms capable of producing valuable bioproducts including triacylglycerides (TAGs) for biodiesel and carotenoids for nutraceuticals. The name “oleaginous yeasts” is conferred based on their ability to synthesize and accumulate TAGs to over 20% of their dry cell weight. Their colours are indicative of the presence of the major carotenoids present in them. Full article

Recently, there has been great interest in the lipidomic of marine lipids and their potential health benefits. Processing of seafood products can potentially modify the characteristics and composition of lipids. The present study investigated the effect of processing methods (salting and fermentation) on the positional distribution of fatty acids of Chinook salmon roe using ¹³C nuclear magnetic resonance spectroscopy (NMR). The NMR analysis provided information on the carbonyl atom, double bond/olefinic, glycerol backbone, aliphatic group, and chain ending methyl group regions. The obtained data showed that docosahexaenoic acid (DHA) is the main fatty acid esterified at the sn-2 position of the triacylglycerides (TAGs), while other fatty acids, such as eicosapentaenoic acid (EPA) and stearidonic acid (SDA), were randomly distributed or preferentially esterified at the sn-1 and sn-3 positions. Fermentation of salmon roe was found to enrich the level of DHA at the sn-2 position of the TAG. The processing of roe by both salt drying and fermentation did not appear to affect the proportion of EPA at the sn-2 position. This present study demonstrated that fish roe processing can enhance the proportion of DHA at the sn-2 position and potentially improve its bioavailability. Full article

Lipid metabolism is a complex process and it is extremely helpful to simulate its performance with different models that explain all the biological processes that comprise it, which then enables its better understanding as well as understanding the kinetics of the process itself. Typically, kinetic parameters are obtained from a number of sources under specific experimental conditions, and they are a source of uncertainty. Sensitivity analysis is a useful technique for controlling the uncertainty of model parameters. It evaluates a model’s dependence on its input variables. In this work, hepatic lipid metabolism was mathematically simulated and analyzed. Simulations of the model were performed using different initial plasma glucose (G_B) and plasma triacylglyceride (TAG) concentrations according to proposed menus for different meals (breakfast, lunch, snack and dinner). A non-stationary Fourier amplitude sensitivity test (FAST) was applied to analyze the effect of 78 kinetic parameters on 24 metabolite concentrations and 45 reaction rates of the biological part of the hepatic lipid metabolism model at five time points (t_f = 10, 50, 100, 250 and 500 min). This study examined the total influence of input parameter uncertainty on the variance of metabolic model predictions. The majority of the propagated uncertainty is due to the interactions of numerous factors rather than being linear from one parameter to one result. Obtained results showed differences in the model control regarding the different initial concentrations and also the changes in the model control over time. The aforementioned knowledge enables dietitians and physicians, working with patients who need to regulate fat metabolism due to illness and/or excessive body mass, to better understand the problem. Full article

The study analyzes the dynamics in the lipid profile of the Endomyces magnusii yeast during the long-lasting cultivation using the substrates of “enzymatic” or “oxidative” type. Moreover, we studied its changes upon calorie restriction (CR) (0.5% glucose) and glucose depletion (0.2% glucose). Di-(DAGs), triacylglycerides (TAGs) and free fatty acids (FFAs) dominate in the storage lipid fractions. The TAG level was high in all the cultures tested and reached 80% of the total lipid amount. While being cultured on 2% substrates, the level of storage lipids decreased at the four-week stage, whereas upon CR their initially low amount doubled. Phosphatidylethanolamines (PE), sterols (St) (up to 62% of total lipids), phosphatidylcholines (PC), and phosphatidic acids (PA) (more than 40% of total lipids) were dominating in the membrane lipids of E magnusii. Upon CR at the late stationary growth stages (3–4 weeks), the total level of membrane lipid was two-fold higher than those on glycerol and 2% glucose. The palmitic acid C16:0 (from 10 to 23%), the palmitoleic acid C16:1 (from 4.3 to 15.9%), the oleic acid C18:1 (from 23.4 to 59.2%), and the linoleic acid C18:2 (from 10.8 to 49.2%) were the dominant fatty acids (FAs) of phospholipids. Upon glucose depletion (0.2% glucose), the total amount of storage and membrane lipids in the cells was comparable to that in the cells both on 2% and 0.5% glucose. High levels of PC and sphingolipids (SL) at the late stationary growth stages and an increased PA level throughout the whole experiment were typical for the membrane lipids composition upon the substrate depletion. There was shown a crucial role of St, PA, and a high share of the unsaturated FAs in the membrane phospholipids upon the adaptation of the E. magnusii yeast to the long-lasting cultivation upon the substrate restriction is shown. The autophagic processes in some fractions of the cell population provide the support of high level of lipid components at the late stages of cultivation upon substrate depletion under the CR conditions. CR is supposed to play the key role in regulating the lipid synthesis and risen resistance to oxidative stress, as well as its possible biotechnological application. Full article

Intrauterine growth restriction (IUGR) due to fetal exposure to glucocorticoid excess results in metabolic inflexibility and hepatic steatosis upon nutritional stress during adulthood. We previously demonstrated that rats born to dexamethasone (DEX)-treated mothers developed hepatic steatosis when exposed to 10% fructose solution during adult life. Persistent triacylglyceride (TAG) accumulation in the liver, in turn, is a feature of non-alcoholic fatty liver disease (NAFLD), which serves as a risk factor for non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC). In the present study, we demonstrate that the combination of IUGR and fructose treatment during adulthood also results in increased hepatic myeloperoxidase (MPO) activity, AKT phosphorylation and serum aspartate transaminase. Growth-restricted rats also presented reduced hepatic TRIB3 and GADD45a after fructose treatment. Other markers of cell proliferation, such as Cyclin D, PCNA, Hgf and Hspa4/Hsp70 expression and the number of Ki-67 positive cells, were all increased in the liver of growth- restricted rats treated with fructose. On the other hand, the combination of IUGR and fructose treatment during adult life reduced the levels of IGF-1. In conclusion, our data indicate that after exposure to fructose, adult rats subjected to dexamethasone-induced IUGR display exacerbated molecular changes in markers of NASH and HCC. Full article

The study of milk fat composition is a priority topic at the international level; however, there are few studies on the composition of triacylglycerides (TAG) and sterols in cow’s milk produced in organic production systems. The objective of this study was to determine the profile of TAG, cholesterol, and other sterols in the fat of raw cow’s milk produced under organic conditions in the municipality of Tecpatán, Chiapas. Every month for one year, milk samples were obtained from three production units (PU 1, 2 and 3) and from the collecting tank (CT) of the municipality (12 months × 4 = 48 samples), in accordance with Mexican regulations. Milk fat was extracted by detergent solution and TAG and sterol analyses were performed by gas chromatography with a flame ionization detector and capillary columns. Chromatographic analyses identified and quantified 15 TAG in all milk fats, from C26 to C54, with a bimodal behavior; the maximum value (% w/w) for the first mode was located at C38 (14.48) and, for the second mode, C50 and C52 were considered with values of 11.55 and 11.60, respectively. Analysis of variance (ANOVA) followed by Tukey’s test only yielded significance (p < 0.05) for C26; most TAG values over time showed homogeneous variability. Cholesterol, brassicasterol, and campesterol were also determined; ANOVA did not show statistical significance (p ≥ 0.05) between them in the production units and collecting tank. Cholesterol had the highest percentage of the sterols with a mean value of 96.41%. The TAG and cholesterol profiles found in this study were similar to those reported in other countries. Full article

1,3-Dipalmitoyl-2-oleoylglycerol (POP) is a triacylglyceride found in oils from various natural sources, including palm kernels, sunflower seeds, and rice bran. In the current study, the neuroprotective effects and the specific mechanism of POP derived from rice bran oil were investigated for the first time using the middle cerebral artery occlusion/reperfusion (MCAO/R) model in rats. Orally administered POP at 1, 3, or 5 mg/kg (three times: 0.5 h before MCAO, after 1 h of MCAO, and after 1 h of reperfusion) markedly reduced the MCAO/R-induced infarct/edema volume and neurobehavioral deficits. Glutathione depletion and the oxidative degradation of lipids in the rat brain induced by MCAO/R were prevented by POP administration. The upregulation of phosphorylated p38 MAPKs, inflammatory factors (inducible nitric oxide synthase (i-NOS) and cyclooxygenase-2 (COX-2)), and pro-apoptotic proteins (B-cell lymphoma-2 (Bcl-2) associated X protein (Bax) and cleaved caspase-3) and the downregulation of the anti-apoptotic protein (Bcl-2) in the ischemic brain were significantly inhibited by POP administration. In addition, downregulation of phosphatidylinositol 3′-kinase (PI3K), phosphorylated protein kinase B (Akt), and phosphorylated cyclic (adenosine monophosphate) AMP responsive element-binding protein (CREB) expression in the ischemic brain was inhibited by POP administration. These results suggest that POP might exert neuroprotective effects by inhibition of p38 MAPK and activation of PI3K/Akt/CREB pathway, which is associated with anti-oxidant, anti-apoptotic, and anti-inflammatory action. From the above results, the present study provides evidence that POP might be effectively applied for the management of cerebral ischemia-related diseases. Full article

Overcoming obstacles to commercialization of algal-based processes for biofuels and co-products requires not just piecemeal incremental improvements, but rather a comprehensive and fundamental re-consideration starting with the selected algae and its associated cultivation, harvesting, biomass conversion, and refinement. A novel two-stage process designed to address challenges of mass outdoor microalgal cultivation for biofuels and co-products was previously demonstrated using an oleaginous, haloalkaline-tolerant, and multi-trophic green Chlorella vulgaris. ALP2 from a soda lake. This involved cultivating the microalgae in a fermenter heterotrophically or photobioreactor mixotrophically (first-stage) to rapidly obtain high cell densities and inoculate an open-pond phototrophic culture (second-stage) featuring high levels of NaHCO₃, pH, and salinity. An improved two-stage cultivation that instead sustainably used as more cheap and sustainable inputs the organic carbon, nitrogen, and phosphorous from fractionation of waste was here demonstrated in a small-scale biorefinery process. The first cultivation stage consisted of two simultaneous batch flask cultures featuring (1) mixotrophic cell productivity of 7.25 × 10⁷ cells mL⁻¹ day⁻¹ on BG-11₀ medium supplemented with 1.587 g L⁻¹ urea and an enzymatic hydrolysate of pre-treated (torrefaction + grinding + ozonolysis + soaking ammonia) wheat-straw that corresponded to 10 g L⁻¹ glucose, and (2) mixotrophic cell productivity of 2.25 × 10⁷ cells mL⁻¹ day⁻¹ on BG-11₀ medium supplemented with 1.587 g L⁻¹ urea and a purified and de-toxified condensate of pre-treated (torrefaction + grinding) wheat straw that corresponded to 0.350 g L⁻¹ of potassium acetate. The second cultivation stage featured ¹H NMR-determined phototrophic lipid productivity of 0.045 g triacylglycerides (TAG) L⁻¹ day⁻¹ on BG-11₀ medium supplemented with 16.8 g L⁻¹ NaHCO₃ and fed batch-added 22% (v/v) anaerobically digested food waste effluent at HCl-mediated pH 9. Full article