Search Results (110)

Diacylglycerol-O-acyltransferase 1 (DGAT1, EC 2.3.1.20) is a pivotal enzyme in plant triacylglycerol (TAG) biosynthesis. Previous work identified conserved di-arginine (R) motifs (R-R, R-X-R, and R-X-X-R) in its N-terminal cytoplasmic acyl-CoA binding domain. To elucidate their functional significance, we engineered R-rich sequences in the N-termini of Tropaeolum majus and Zea mays DGAT1s. Comparative analysis with their respective non-mutant constructs showed that deleting or substituting R with glycine in the N-terminal region of DGAT1 markedly reduced lipid accumulation in both Camelina sativa seeds and Saccharomyces cerevisiae cells. Immunofluorescence imaging revealed co-localization of non-mutant and R-substituted DGAT1 with lipid droplets (LDs). However, disruption of an N-terminal di-R motif destabilizes DGAT1, alters LD organization, and impairs recombinant oleosin retention on LDs. Further evidence suggests that the di-R motif mediates DGAT1 retrieval from LDs to the endoplasmic reticulum (ER), implicating its role in dynamic LD–ER protein trafficking. These findings establish the conserved di-R motifs as important regulators of DGAT1 function and LD dynamics, offering insights for the engineering of oil content in diverse biological systems. Full article

Safflower (Carthamus tinctorius L.) seeds, rich in triacylglycerols, have poor fatty acid-to-sugar conversion during storage, affecting longevity and vigor. Previous experiments have shown that the aging of safflower seeds is mainly related to the impairment of energy metabolism pathways such as glycolysis, fatty acid degradation, and the tricarboxylic acid cycle. The treatment with exogenous sucrose can partially promote the germination of aged seeds. However, the specific pathways through which exogenous sucrose promotes the germination of aged safflower seeds have not yet been elucidated. This study aimed to explore the molecular mechanism by which exogenous sucrose enhances the vitality of aged seeds. Phenotypically, it promoted germination and seedling establishment in CDT-aged seeds but not in unaged ones. Biochemical analyses revealed increased soluble sugars and fatty acids in aged seeds with sucrose treatment. Enzyme activity and transcriptome sequencing showed up-regulation of key enzymes and genes in related metabolic pathways in aged seeds, not in unaged ones. qPCR confirmed up-regulation of genes for triacylglycerol and fatty acid-to-sugar conversion. Transmission electron microscopy showed a stronger connection between the glyoxylate recycler and oil bodies, accelerating oil body degradation. In conclusion, our research shows that exogenous sucrose promotes aged safflower seed germination by facilitating triacylglycerol hydrolysis, fatty acid conversion, and glycometabolism, rather than simply serving as a source of energy to supplement the energy deficiency of aged seeds. These findings offer practical insights for aged seeds, especially offering an effective solution to the aging problem of seeds with high oil content. Full article

Alpha/beta hydrolase (ABHs) fold esterase/lipase proteins represent a prominent family within the serine hydrolase (SH) superfamily that includes esterases and lipases and other catalytic and non-catalytic proteins. ABHs play crucial roles in both the fundamental and secondary metabolic pathways, including the synthesis and degradation of triacylglycerols (TAGs), key components of plant oils. Despite their importance in oil production, the ABH gene family in the oil crop Brassica napus has not been comprehensively analyzed. In the present study, we identified 777 BnABH genes in the B. napus cultivar ‘Zhongshuang 11’ (ZS11). Phylogenetic analysis categorized these BnABH genes into 10 distinct groups. Twenty-four BnABHs were identified through esterase activity staining and mass spectrometry, 11 of which were classified into clade C3. Examination of the gene and protein structures, expression patterns, and cis-elements of the BnABHs in clade C3 suggested diverse functional roles across different tissues and in response to various environmental stresses. In particular, BnABH205 was highly induced by high temperatures. Subcellular localization analysis revealed that the BnABH205 protein was localized to the plastid. Further analysis revealed five haplotypes within the coding and 3′ untranslated regions of BnABH205 that were significantly associated with seed oil content (SOC). Overall, this study provides a comprehensive understanding of BnABHs and introduces a robust methodology for identifying potential esterase/lipase genes that regulate seed oil content (SOC) in response to environmental hazards, especially heat waves during seed maturation. Full article

Background: Neem seed oil (Azadirachta indica A. Juss) is widely used in the pharmaceutical, agricultural, and food industries due to its antiseptic, fungicidal, pesticidal, and antioxidant properties, attributed to over 300 bioactive compounds and a high content of unsaturated fatty acids. Methods: This study aimed to characterize a commercial sample of neem oil regarding its physicochemical properties and identity profile, using official methodologies from the American Oil Chemists’ Society (AOCS), and to compare the results with literature data. Results: The sample exhibited the following parameters: free fatty acids (2.0 ± 0.02%), acidity index (3.9 ± 0.04 mg KOH/g), peroxide value (3.2 ± 0.1 mEq/kg), iodine value (116 ± 12 g I₂/100 g), and saponification index (198 ± 8 mg KOH/g). The predominant coloration was yellowish, with total chlorophyll and carotenoid levels below the equipment’s quantification limits. Fatty acid composition was mainly long-chain (C16–C18), with notable levels of linoleic acid (46%), oleic acid (28%), palmitic acid (12%), linolenic acid (5.5%), and stearic acid (4.1%). The triacylglycerol profile showed a predominance of triunsaturated (51%) and diunsaturated species (41%). Differential scanning calorimetry (DSC) analysis revealed crystallization events between −6 °C and −57 °C and fusion events between −44 °C and −1 °C, consistent with the high unsaturation level of the lipids. Conclusions: The analyzed neem oil sample meets quality and identity criteria, making it suitable for various industrial applications. The characterization confirms its potential and aligns with literature data, emphasizing its relevance for industrial use. Full article

Background/Objectives: Regiospecificity in triacylglycerols (TAGs) influences absorption/bioavailability of dietary fatty acids. We evaluated whether sn1,3 located DHA (22:6ω3) of a transgenic higher plant (DHA-Canola^®) preferentially facilitates its tissue incorporation as compared to sn2 positioned DHA (DHASCO^® of algal origin). Methods: Sprague Dawley rats were fed diets (12 weeks) containing DHA-Canola or DHA-Control (a blend of DHASCO^® and high oleic sunflower seed oil (HOSO)) at 0.3%, 1%, 3%, and 6% (w/w), or 7% HOSO prior to determination of tissue fatty acids. Results: At 0.3 and 1% w/w supplementation, plasma, liver and cardiac tissue DHA incorporation was higher in the plant-based oil (DHA-Canola vs. DHA-Control; p < 0.05), whilst sn2 enriched algal oil yielded better outcomes at higher doses (at 3% inclusion, plasma values were 7.8 vs. 5.9%, and at 6% supplementation, 10.0 vs. 7.9 in favor of DHA-Control, p < 0.05) At lower intakes, sn1,3 regiospecificity (DHA-Canola) increased the omega-3 index, a clinically relevant biomarker, compared to DHA-Control (p < 0.05). Similarly, a build-up of 20:5ω3 and 22:5ω3 occurred with DHA-Canola. Consequently, total omega3s were higher in this latter group. Conclusions: At lower intakes, sn1,3 regiospecificity of DHA leads to its preferential tissue incorporation compared to sn2 DHA. Full article

Background/Objectives: Sunflower (Helianthus annuus L.) is one of the four major global oilseed crops. Understanding the molecular mechanisms regulating fatty acid synthesis and triacylglycerol (TAG) accumulation is crucial for improving oil yield and quality. In this study, the oilseed sunflower cultivar ‘T302’, which was wild-cultivated in the northwestern region of China, was analyzed for fatty acid content by targeted lipidomic analysis. RNA sequencing (RNA-seq) was performed on 15 cDNA libraries from sunflower embryos at five developmental stages (10, 17, 24, 31, and 38 days after flowering) to investigate gene expression patterns during oil accumulation. Differentially expressed genes (DEGs) related to fatty acid and triacylglycerol accumulation in developing sunflower seeds were identified. WGCNA was used to gain deeper insights into the mechanisms underlying lipid metabolism. Results: The oil composition of ‘T302’ consisted of 86.61% unsaturated fatty acids (UFA), mainly linoleic acid (48.47%) and oleic acid (37.25%). Saturated fatty acids (SFAs) accounted for 13.39%, with palmitic acid (7.46%) and stearic acid (5.04%) being the most abundant. A total of 81,676 unigenes were generated from RNA-seq data, and 91 DEGs associated with lipid metabolism were identified, including key enzymes such as FAD2-1, SAD, FATA, LACS, PDAT2, and DGAT2. In addition, we identified several novel candidate transcription factor genes, including WRI1, LEC1, FUS3, and ABI3, which were found to regulate TAG synthesis during seed maturation and are worthy of further investigation. This study provides valuable insights into the molecular mechanisms of seed oil biosynthesis in oilseed sunflower. The identified key genes and transcription factors provide potential targets for molecular breeding strategies to increase oil content and modify fatty acid compositions in sunflower and other oilseed crops. Full article

This article represents the first consideration of the peculiarities of the fatty acid (FAs) composition and structure of storage triacylglycerols (TAGs) of the relict plant Lunaria rediviva L. The composition of storage TAGs was found to comprise 21 individual FAs, with an unsaturated FA content of 96.8%. Additionally, monounsaturated acids with a very long chain (VLCFAs), specifically C20:1–C24:1, constituted over 60% of the total FAs. The ethylene bond position isomers of unsaturated FAs were accurately identified and the presence of unusual isomers, including 20:1$\Delta$13, 22:1$\Delta$15, and 24:1$\Delta$17 acids. Furthermore, the unusual minor 24:2$\Delta$15,18 acid was identified and characterised for the first time. The pathways of the mentioned VLCFA’s biosynthesis have been proposed. The distribution of FA acyls between the sn positions of triacylglycerols was found to be highly specific. Thus, VLCFAs exclusively acylate the $\alpha$ positions of the carbon atoms of the glycerol residue of the TAG molecule (sn-1 and sn-3 positions), while unsaturated C18 acids exclusively acylate the $\beta$-carbon atom (sn-2 position). The composition of the molecular species of TAGs was analysed using a calculation method based on the Vander Wal model and by RP-HPLC-ESI-MS. A significant discrepancy from the statistical model was observed, indicating a preference for the formation of symmetrical TAGs, such as sn-1,3-dierucoyl-2-oleoyl-glycerol and related molecular species. This observation led to the formulation of a hypothesis regarding the potential existence of at least two specialised enzyme isoforms involved in the biosynthesis of such TAGs via the Kennedy pathway, exhibiting unusual substrate specificity. Consequently, this plant can be regarded not only as a producer of unusual molecular types of triacylglycerols but also as a source of genetic material for the search of genes encoding the aforementioned enzymes with unusual substrate specificity. Full article

The seeds of Corema album are considered a by-product in fruit processing. This study aimed to determine the oil contents in seeds and characterize their triacylglycerol contents through a comparative analysis using three extraction solvent systems: hexane (Soxhlet method), hexane–isopropanol (Hara–Radin method), and methanol–chloroform–water (Bligh–Dyer method). The extracts were analyzed by gas chromatography/mass spectrometry and HPLC. The composition of fatty acids and triacylglycerols was determined, as were the allocation of fatty acids across the sn-2 and sn-1,3 positions, tocopherol and tocotrienol profile, and melting behavior through differential scanning calorimetry. Furthermore, the atherogenicity (IA) and thrombogenicity (IT) cardiovascular health indices were also calculated. The oil predominantly contained unsaturated fatty acids, and α-linolenic acid made up 45.8% of the total, along with a reduced n-6/n-3 fatty acid ratio (0.75). The α-linolenoyl chain primarily occupied the sn-1,3 (45.9%) and sn-2 (39.1%) positions. γ-tocotrienol was the most abundant tocochromanol. The melting curve of oil suggests the presence of fractions with a low melting point, composed of triacylglycerols containing polyunsaturated fatty acids. The oil exhibits low values for IA and IT of 0.05 and 0.04, respectively. Corema seed oil has potential health benefits thanks to its rich composition in the essential fatty acid, α-linolenic acid, the low proportion of n-6/n-3 fatty acids, and the low values of IA and IT. Full article

Mangosteen seed fat (MSF), a novel tropical seed fat, predominantly comprises 1,3-distearoyl-2-linoleoyl-glycerol (StLSt) and 1,3-distearoyl-2-oleoyl-glycerol (StOSt). The fat was blended with cocoa butter (CB) in proportions of 5%, 25% and 60% in the present study, and the binary blends achieved acceptable miscibility. It was indicated that StLSt could be mixed well with the symmetrical monounsaturated triacylglycerols in CB, especially StOSt, 1-palmitoyl-2-oleoyl-3-stearoyl-glycerol (POSt) and 1,3-dipalmitoyl-2-oleoyl-glycerol (POP). Although the solid fat contents of the binary blends gradually decreased with the addition of MSF, which resulted from low-melting triacylglycerols in MSF, the well-compatible fat matrix contributed to keeping their desirable melting behaviors and hardness at hot temperatures. A chocolate fat bloom test showed that replacing CB with 25–60% MSF improved fat-bloom-resistant stabilities effectively. The effective steric hindrance of StLSt crystals may improve fat compatibilities and further delay liquid–oil migration and recrystallization in chocolates during temperature fluctuations. Full article

The cold-pressed oil from Japanese quince seeds (JQSO) is notable for its favorable fatty acid profile, low oxidation rate, and bioactive compounds like antioxidants, sterols, and carotenoids. This study offers a detailed molecular-level physical characterization of JQSO and its minor components using differential scanning calorimetry (DSC), Langmuir monolayer studies, and various spectroscopic methods, including UV–vis absorption, fluorescence, and FTIR. DSC analysis identified five peaks related to triglyceride (TG) fractions and provided insights into the melting and crystallization behavior of JQSO. The Langmuir monolayer studies revealed high compressibility, indicative of superior emulsification properties. Viscoelastic modulus measurements suggested strong intermolecular interactions, contributing to the oil’s resilience under stress—an attribute typical of oils high in saturated or monounsaturated fatty acids. Spectroscopic methods confirmed the presence of phenolic acids, tocopherols, carotenoids, and their derivatives. The total fluorescence spectra highlighted prominent peaks at 290 nm/330 nm and 360 nm/440 nm, while the total synchronous fluorescence spectra revealed key excitation–emission regions (10–50 nm/300 nm and 40–140 nm/360 nm), corroborating the presence of tocopherols, phenols, polyphenols, flavones, and carotenoids. No evidence of chlorophyll was detected. The ATR-FTIR spectra validated the presence of fatty acids and triacylglycerols, emphasizing a high degree of esterification and the dominance of unsaturated fatty acids in oil structures. The methods used provided the opportunity to perform a label-free, fast, and reliable determination of the properties of JQSO. The findings confirmed that crude, cold-pressed JQSO retains its valuable bioactive components, aligning with previous research on its chemical and physical properties. Full article

Oil cakes are biomass wastes created by pressing oil from oilseeds. Their chemical composition (including high fat or protein content, a favorable fatty acid profile, and a high proportion of unsaturated acids) makes them valuable raw materials not only in animal feeding but are increasingly gaining popularity in biotechnological processes. This article examines the possibility of valorizing oil cakes using the lipid fraction extracted from them or their raw form in a two-pot biosynthesis process of GDDL—a cyclic ester with a creamy-peach aroma. This study tested five types of oil cakes (hemp seeds, rapeseed, safflower, camelina, and flax), analyzing their physicochemical composition and the fatty acid profile of their lipid fraction. Due to the high content of oleic acid (over 62% lipid fraction) and the wide availability, rapeseed cake was used in the biotransformation process. The synthesis of GDDL involved a three-step process: hydrolysis of triacylglycerols, hydration of oleic acid (via lactic acid bacteria in anaerobic conditions), and β-oxidation (via Yarrowia yeast, aerobic process). The analysis showed that it is possible to produce because of the two-pot biotransformation of approximately 1.7 g of GDDL/dm³. These results highlight the process’s potential and justify the feasibility of waste valorization. The proposed biotransformation requires optimization and is a good example of the application of the circular economy in food processing and waste management. Full article

This study characterized the quality of hemp oil (HO) and pumpkin seed oil (PO) and their blends before and after 2 and 4 months of storage at refrigerated and room temperature, without access to light and oxygen. The analyses included determining the acid value, peroxide value, fatty acid (FA) composition, and FA distribution in triacylglycerol (TAG) molecules. Pressure differential scanning calorimetry (PDSC) was used to assess the oxidative stability of oils and their blends. This study also evaluated the nutritional potential of hemp oil and pumpkin seed oil blends, as atherogenicity, thrombogenicity, and health-promoting indices and hypocholesterolaemic/hypercholesterolaemic ratio were calculated. The tested samples differed in properties depending on the storage time and temperature. The optimal choice was a blend of 50% hemp oil (HO) and 50% pumpkin oil (PO). This mixture demonstrated the desired fatty acid composition, satisfactory acid and peroxide values, and a relatively good oxidation induction time during storage. Despite the unfavorable distribution of FAs in TAG molecules, it was characterized by a balanced ratio of n-3 to n-6 acids. It was also concluded that research on HO and PO mixtures should be continued due to the potential synergistic effect of their bioactive substances. Full article

Phospholipid: diacylglycerol acyltransferase (PDAT) is crucial in triacylglycerol (TAG) synthesis as it represents the final rate-limiting step of the acyl-CoA-independent acylation reaction. PDAT not only regulates lipid synthesis in plants, but also plays an important function in improving stress tolerance. In this study, the full-length coding sequence (CDS) of XsPDAT1, totaling 2022 base pairs and encoding 673 amino acids, was cloned from Xanthoceras sorbifolium. The relative expression of XsPDAT1 was significantly and positively correlated with oil accumulation during seed kernel development; there were some differences in the expression patterns under different abiotic stresses. Transgenic Arabidopsis thaliana plants overexpressing XsPDAT1 were obtained using the Agrobacterium-mediated method. Under low-temperature stress, the transgenic plants exhibited a smaller decrease in chlorophyll content, a smaller increase in relative conductivity, and a larger increase in POD enzyme activity and proline content in the leaves compared with the wild type. Additionally, lipid composition analysis revealed a significant increase in unsaturated fatty acids, such as oleic (C18:1) and linoleic (C18:2), in the seeds of transgenic plants compared to the wild type. These results suggest that XsPDAT1 plays a dual role in regulating the ratio of fatty acid composition and low-temperature stress in plants. Full article

Punicic acid (PuA) is a conjugated fatty acid with a wide range of nutraceutical properties naturally present in pomegranate seed oil. To meet the rising demand for pomegranate seed oil, a single-cell oil enriched in PuA provides a sustainable biomass-derived alternative. This study describes the production of a PuA-enriched single-cell oil through the engineering of the red yeast Rhodotorula toruloides grown in glucose and a low-cost substrate, crude glycerol. The gene for Punica granatum fatty acid conjugase, PgFADX, was randomly integrated into the genome of R. toruloides without disrupting the carotenoid synthesis. In shake flask studies, the effects of three promoters (P_PGI1, P_NAR1, and P_PMA1) on PuA production were evaluated. PuA titers of 105.77 mg/L and 72.81 mg/L were obtained from engineered cells expressing PgFADX from the P_PMA1 promoter cultivated for 72 h in glucose and for 168 h in crude glycerol, respectively. Furthermore, the detailed lipid analysis revealed a high enrichment PuA in the triacylglycerol lipid structures, even without substantial modifications to the metabolic pathways. This report demonstrates the high potential of R. toruloides in the upcycling of a low-cost substrate, crude glycerol, into a value-added product such as PuA. The findings support the feasibility of using engineered R. toruloides for sustainable production of PuA-enriched single-cell oil. Full article

The interesterification process allows structured lipids (SLs) to be obtained with a modified triacylglycerol (TAG) structure, in which the unfavorable saturated fatty acids (SFAs) are replaced with nutritionally significant fatty acids (FAs) such as monounsaturated (MUFAs) and polyunsaturated (PUFAs). Oxidative stability is crucial for the quality of SLs. This study aimed to characterize and evaluate the FA profile and oxidative stability of SLs synthesized by the enzymatic interesterification of hemp seed oil (HO) and coconut oil (CO) blends. Blends were prepared in three ratios (75% HO:25% CO, 50% HO:50% CO, and 25% HO:75% CO) and interesterified using sn-1,3 regiospecific lipase for 2 or 6 h. FA composition, the FA distribution of TAGs, acid value (AV), peroxide value (PV), and oxidation time were analyzed and compared to non-interesterified blends. Results showed no significant difference in the SFA:MUFA ratios between interesterified and non-interesterified blends with the same proportions. Lauric acid predominantly occupied the sn-2 position in all blends. Interesterified blends had higher AVs, exceeding codex standards, while PVs remained within the acceptable limits. Blends with 75% HO had lower oxidation times compared to those with 75% CO, with no significant difference between interesterified and non-interesterified blends. In the interesterification process of the studied blends, new TAGs with a modified structure were created, which may affect their physical and nutritional properties. This process also had a significant effect on the AV and PV levels, but not on the oxidation time of the modified blends. Therefore, it is necessary to remove free FAs after the enzymatic process to produce SLs characterized by improved hydrolytic stability. This will lead to better technological properties compared to the original oils. Further research is also necessary to enhance the oxidation stability of SLs obtained from blends of CO and HO to improve their storage stability. Full article