Search Results (432)

Punicic acid is an uncommon ω-5 conjugated fatty acid with significant biological activity, mainly found in pomegranate seed oil. Due to limited natural availability, heterologous production of punicic acid in oleaginous yeasts offers a sustainable alternative. In this study, Yarrowia lipolytica was engineered for punicic acid biosynthesis by expressing the PgFADX gene from Punica granatum and subsequently modified to evaluate the influence of distinct diacylglycerol acyltransferases on punicic acid accumulation. The effects of seven acyltransferases, originating from P. granatum or Y. lipolytica, were compared under various cultivation conditions. The PgDGAT1 enzyme demonstrated the most favorable balance between total lipid content and punicic acid accumulation. Medium containing crude glycerol as a low-cost carbon source was initially tested in flask experiments with punicic acid accumulation in yeast cells of 129 mg/L. Further optimization of crude glycerol medium and subsequent scale-up experiments confirmed the potential of crude glycerol as an effective substrate, yielding up to 147.8 mg/L of punicic acid. Overall, this work identifies key enzymatic determinants for efficient punicic acid biosynthesis and supports Y. lipolytica as a robust host for the sustainable production of conjugated fatty acids from waste substrates. Full article

The evolution of type I polyketide synthase (T1PKS) assembly lines remains poorly understood. Through systematic mining of polyene biosynthetic gene clusters, we identified a novel eurocidin biosynthetic pathway capable of producing identical compounds with divergent loading module architectures, thereby capturing an evolutionary transitional state. Biochemical analysis revealed unprecedented functional reprogramming of acyltransferase (AT) domains, shifting substrate specificity from extender units (malonyl-CoA) to starter units (acyl-CoA). This paradigm shift enables direct initiation of polyketide chain assembly via AT-mediated loading of starter units, thereby elucidating the origin of extant AT-initiated assembly lines and establishing AT functional plasticity as a novel mechanism for polyketide structural diversification. Parallel evolution of ketosynthase (KS) domains through KSS→KSQ mutations further diversified initiation strategies. Applying this evolutionary insight, we engineered the candicidin pathway by replacing its native aromatic-starting bimodule with a starter-selective monomodule from eurocidin, generating aliphatic-starting analogs. This demonstrates that evolution-inspired AT reprogramming provides a rational framework for modifying polyketide starter units, expanding structural diversity, and enhancing therapeutic potential. Full article

Due to the neuroprotective and antioxidant properties, phenylethanoid glycosides (PhGs) are valuable plant-derived compounds. Traditional extraction methods are constrained by low yields and limited resources, prompting the integration of synthetic biology and enzyme engineering technologies for sustainable production. This review summarizes the advances in the microbial synthesis of PhGs, emphasizing the elucidation of biosynthetic pathways, enzyme engineering modifications of glycosyltransferases and acyltransferases, and strategies for optimizing microbial cell factories in Escherichia coli and Saccharomyces cerevisiae. Significant advancements encompass the efficient synthesis of verbascoside and echinacoside in S. cerevisiae, as well as the comprehensive elucidation of the echinacoside biosynthetic pathway in Cistanche spp., including the identification of key steps catalyzed by a rhamnosyltransferase, a CYP450 hydroxylase, and a terminal glucosyltransferase that enable pathway reconstruction in S. cerevisiae. We conduct a systematic analysis of methods to address the biosynthetic bottlenecks via protein engineering, including rational design and directed evolution, as well as the metabolic engineering strategies such as precursor enhancement and cofactor recycling. Additionally, we investigate the synthesis of non-natural PhG analogues and the prospective integration with AI-assisted design, emphasizing the significant potential of microbial systems in overcoming the supply challenges for medicine-food homologous ingredients. Full article

The global change toward sustainable manufacturing has intensified the development of alternatives to petrochemical-based surfactants, which are environmentally recalcitrant and fossil dependent. Biosurfactants have emerged as the most promising petrochemical-based surfactant substitutes, due to their biodegradability, low toxicity, and robust performance under extreme conditions; however, their industrial use is hindered by high production costs, limited productivity, and complex downstream processing, for instance high protein content can make the ultrafiltration (downstream strategy) unfeasible. This review critically examines recent advances in integrated bioprocess design to overcoming these constraints, with particular emphasis on the convergence of enzymatic catalysis and microbial fermentation. Comparative assessment across key biosurfactant classes demonstrates that tailored enzymatic transformations, enabled by lipases, glycosyltransferases, acyltransferases, and oxidoreductases, offer precision in structural modification unattainable through fermentation alone, enabling programmable amphiphilicity and improved functional performance. Thus, the translation of enzymatic and hybrid routes to industry remains restricted by enzyme stability, cofactor regeneration, and process engineering challenges. Emerging strategies such as continuous fermentation, in situ product recovery, and machine learning-based process control show strong potential to enhance productivity and reduce energy demands. By integrating molecular design, metabolic engineering, and intensified bioprocessing, this review delineates a strategic framework for advancing next-generation biosurfactants toward commercial viability within circular and sustainable value chains. Full article

This study evaluated the protective effects of naringin (NG) against intestinal injury in 7-day-old piglets infected with porcine epidemic diarrhea virus (PEDV). Eighteen piglets (Duroc × Landrace × Large, body weight = 2.58 ± 0.05 kg) were divided into three treatment groups based on similar body weights and equal numbers of males and females: the blank control group (CON group), the PEDV infection group (PEDV group), and the NG intervention + PEDV infection group (NG + PEDV group) (n = 6 per group). The experiment lasted for 11 days, comprising a pre-feeding period from days 0 to 3 and a formal experimental period from days 4 to 10. On days 4–10 of the experiment, piglets in the NG + PEDV group were orally administered NG (10 mg/kg). On Day 8 of the experiment, piglets in the PEDV and NG + PEDV groups were inoculated with PEDV (3 mL, 10⁶ 50% tissue culture infective dose (TCID₅₀) per milliliter). On day 11 of the experiment, piglets were euthanized for sample collection. PEDV infection caused significant intestinal damage, including a decreased (p < 0.05) villus height in the duodenum and ileum and an increased (p < 0.05) crypt depth in all intestinal segments. This intestinal damage was accompanied by an impaired absorptive function, as indicated by reduced (p < 0.05) serum D-xylose. Further results showed that PEDV compromised the intestinal antioxidant capacity by decreasing (p < 0.05) glutathione peroxidase and catalase activities, and it stimulated the intestinal inflammatory response by upregulating (p < 0.05) the expression of key inflammatory genes, including regenerating family member 3 gamma (REG3G; duodenum, jejunum, colon), S100 calcium binding protein A9 (S100A9; ileum, colon), interleukin 1 beta (IL-1β; ileum, colon), and S100 calcium binding protein A8 (S100A8; colon). PEDV also suppressed the intestinal lipid metabolism pathway by downregulating (p < 0.05) the ileal expression of Solute Carrier Family 27 Member 4 (SLC27A4), Microsomal Triglyceride Transfer Protein (MTTP), Apolipoprotein A4 (APOA4), Apolipoprotein C3 (APOC3), Diacylglycerol O-Acyltransferase 1 (DGAT1), and Cytochrome P450 Family 2 Subfamily J Member 34 (CYP2J34). Moreover, PEDV suppressed the intestinal antiviral ability by downregulating (p < 0.05) interferon (IFN) signaling pathway genes, including MX dynamin like GTPase 1 (MX1) and ISG15 ubiquitin like modifier (ISG15) in the duodenum; weakened intestinal water and ion transport by downregulating (p < 0.05) aquaporin 10 (AQP10) and potassium inwardly rectifying channel subfamily J member 13 (KCNJ13) in the duodenum, aquaporin 7 (AQP7) and transient receptor potential cation channel subfamily V member 6 (TRPV6) in the ileum, and TRPV6 and transient receptor potential cation channel subfamily M member 6 (TRPM6) in the colon; and inhibited intestinal digestive and absorptive function by downregulating (p < 0.05) phosphoenolpyruvate carboxykinase 1 (PCK1) in the duodenum and sucrase-isomaltase (SI) in the ileum. Notably, NG effectively counteracted these detrimental effects. Moreover, NG activated the IFN signaling pathway in the jejunum and suppressed PEDV replication in the colon. In conclusion, NG alleviates PEDV-induced intestinal injury by enhancing the antioxidant capacity, suppressing inflammation, normalizing the expression of metabolic and transport genes, and improving the antiviral ability. Full article

Phospholipid:Diacylglycerol Acyltransferase (PDAT) catalyzes the final step of the acyl-CoA-independent triacylglycerol (TAG) biosynthesis pathway and plays an important role in lipid metabolism and abiotic stress responses in plants. Oat (Avena sativa L.) possesses the highest lipid content among cereal crops, yet the functions of PDAT genes in this species remain largely unexplored. In this study, we identified and characterized three AsPDAT genes in oat, which form a homeologous triplet evenly distributed across the three subgenomes and show high conservation in sequence and gene structure. Phylogenetic analysis indicated a clear divergence between monocot and dicot PDATs. Expression profiling revealed that the three AsPDAT genes share similar organ-specific and stress-responsive expression patterns, suggesting functional conservation following polyploidization, with AsPDAT-5C showing relatively higher transcript levels. The enzymatic activity of AsPDAT-5C was confirmed by complementation of the TAG-deficient yeast quadruple mutant H1246. Transient expression in Nicotiana benthamiana epidermal cells demonstrated that AsPDAT-5C localizes to the endoplasmic reticulum. Stable overexpression of AsPDAT-5C in Nicotiana tabacum significantly increased lipid content in both leaves and seeds without compromising plant growth and enhanced tolerance to cold and phosphorus-deficiency stresses. Our results provide new insights into the AsPDAT gene family and underscore the potential of AsPDAT-5C in engineering lipid biosynthesis and improving stress resilience in plants. Full article

Nonylphenol (NP) bioremediation is constrained by the scarcity of efficient and non-pathogenic degrading strains. To clarify the role of acetyl-CoA C-acetyltransferase (AtoB) in NP degradation, we generated an atoB-overexpressed strain (LY-OE) from the environmentally tolerant Bacillus cereus LY and compared its degradation rate with the wild type using HPLC. Untargeted lipidomics was conducted to characterize metabolic responses under NP stress, and key differential lipid metabolites (DELMs) were further validated by ELISA. Additionally, AtoB concentration and ATP content were quantified using commercial assay kits in Bacillus cereus. LY-OE showed a markedly higher NP degradation rate (96%) than LY (85%). Lipidomic analysis identified 34 significant DELMs (VIP > 1, p < 0.05), including elevated cardiolipin (CL) and phosphatidylglycerol (PG), and reduced phosphatidylcholine (PC) and triglycerides (TG). ELISA confirmed these changes (p < 0.01 or p < 0.001), consistent with lipidomic findings. LY-OE showed significantly higher AtoB concentration during the logarithmic growth phase and exhibited higher ATP content during NP degradation. These findings suggest that atoB overexpression enhances NP degradation by both boosting energy supply and remodeling lipid metabolism. This work identifies atoB as a key factor for NP biodegradation and provides a promising strategy for developing high-performance bioremediation strains. Full article

Astaxanthin is a high-value metabolite with substantial market demand, owing to its potent antioxidant activity and diverse health benefits. Microalgae are considered the primary producers of esterified astaxanthin, yet their industrial-scale cultivation is constrained by low productivity, stress-dependent induction, and challenges in metabolic engineering. This review examines strategies to enhance microalgae-derived esterified astaxanthin production through nanoformulation and modulation of metabolic pathways. We highlight that precise, efficient, and multiplexed genetic modifications of the carotenoid biosynthetic pathway can significantly increase astaxanthin accumulation. Downregulation of competing metabolic routes further improves astaxanthin yields. Additionally, targeted engineering of acyltransferases and lipid metabolism regulators enhances astaxanthin esterification, thereby improving its intracellular stability against oxidative degradation. Modifying lipid metabolism also redirects metabolic fluxes toward altered fatty acid saturation in stored lipids, which increases the bioavailability of esterified astaxanthin. The integration of nanoparticles into cultivation systems represents another promising approach, facilitating improved nutrient delivery and light management, and consequently boosting astaxanthin production. However, the application of genetic engineering and nanotechnology faces challenges such as biosafety legislation, regulatory approval processes, and potential ecological impacts. A synergistic combination of both approaches may help overcome these limitations and maximize astaxanthin production from microalgae. Full article

Our understanding of Ghrelin, an endogenous ligand of the growth hormone secretagogue receptor 1a (GHSR1a), has expanded from considering it to be a “hunger hormone” to a pleiotropic regulator of whole-body physiology. This review synthesizes the current advances spanning ghrelin biogenesis, signaling, and systems biology. Physiologically, preproghrelin processing and O-acylation by ghrelin O-acyltransferase (GOAT) generate acyl-ghrelin, a high-potency GHSR1a agonist; des-acyl ghrelin predominates in circulation and exerts context-dependent, GHSR1a-independent, or low-potency effects, while truncated “mini-ghrelins” can act as competitive antagonists. The emergence of synthetic ligands, agonists, antagonists, and reverse-agonists has provided the necessary tools to decipher GHSR1a activity. Recent cryo-EM structures of GHSR1a with peptide and small-molecule ligands reveal a bipartite binding pocket and provide a framework for biased signaling, constitutive activity, and receptor partner selectivity. Beyond the regulation of feeding and growth-hormone release, ghrelin modulates glucose homeostasis, gastric secretion and motility, cardiovascular tone, bone remodeling, renal hemodynamics, and innate immunity. Ghrelin broadly dampens pro-inflammatory responses and promotes reparative macrophage phenotypes. In the emerging scholarship on ghrelin’s activity in the central nervous system, ghrelin has been found to influence neuroprotection, stress reactivity, and sleep architecture, and has also been implicated in depression, Alzheimer’s disease, and substance-abuse disorders. Practical and transitional aspects are also highlighted in the literature: approaches for ghrelin stabilization; recent GHSR1a agonists/antagonists and inverse agonists findings; LEAP-2-based strategies; and emerging GOAT inhibitors. Together, structural insights and pathway selectivity position the ghrelin system as a druggable axis for the management of inflammatory diseases, neuropsychiatric and addiction conditions, and for obesity treatment in the post-GLP-1 receptor agonist era. Full article

Microsomal fractions from yeast Δale1 cells harbouring the empty plasmid pYES2/CT and from yeast cells overexpressing PtATS2a (Phatr3_J11916) or PtATS2b (Phatr3_J43099) were used in the studies. When sn-1-18:1-LPA and [¹⁴C]16:0-CoA were used as exogenous substrates, both PtATS2a and PtATS2b showed the highest activity at 23 °C in the range of temperatures tested from 10 to 60 °C. Both enzymes showed the highest activity in alkaline pH. For PtATS2a, it was pH 10 while for PtATS2b, it was pH 11. At pH 6 and pH 12, the activities of both enzymes were very low. The calcium ions at concentrations of 0.05–1 mM drastically decreased the activity of both enzymes. The magnesium ions at a concentration of 0.05 mM had a little effect on the activity of both enzymes, while higher concentrations (0.5 mM and 1 mM) significantly inhibited their activity. To study the substrate specificity, seventeen different acyl-CoAs in combinations with sn-1-[¹⁴C]18:1-LPA were used. PtATS2a showed the highest preference for 18:4-CoA n-3 while PtATS2b for 18:1-CoA. The pattern of utilisation of other acyl-CoAs tested also differed between the two enzymes. The presented studies, for the first time, characterised LPAAT type enzymes from diatoms, organisms that naturally produced very-long-chain polyunsaturated fatty acids (VLC-PUFA). Full article

Heat stress induces metabolic adaptations in fish, including the regulation of triglyceride (TG) synthesis/degradation to preserve cellular lipid balance and energy homeostasis. Diacylglycerol acyltransferase (DGAT) catalyzes the final step in TG synthesis. However, the molecular mechanisms by which DGAT regulates TG metabolism in heat-stressed fish remain unexplored. Our previous study suggested that miR-10c regulates dgat2 expression in genetically improved farmed tilapia (GIFT, Oreochromis niloticus) under heat stress. Here, we characterized the GIFT miR-10c precursor as a 65-nucleotide transcript yielding a 22 nt mature miRNA (oni-miR-10c). A phylogenetic analysis revealed a high level of miR-10c sequence conservation across species. A dual-luciferase reporter assay confirmed dgat2 as a direct target of miR-10c. Overexpression of miR-10c in vivo down-regulated dgat2 transcripts and DGAT2 protein. SiRNA-knockdown of dgat2 resulted in upregulation of cpt1α, fas, and lpl and downregulation of hsl, thereby reprogramming lipid metabolism in GIFT hepatocytes. Thus, the miR-10c-dgat2 regulatory axis facilitates TG hydrolysis and promotes fatty acid metabolism under heat stress. Our findings highlight miR-10c’s potential as a dgat2 inhibitor and its function in regulating lipid metabolism in heat-stressed GIFT. Our study reveals a key molecular pathway mediating thermal adaptation of energy metabolism in fish, providing novel targets for preventing heat-induced metabolic disorders. Full article

Evidence indicates that light can trigger an increase in triacylglycerol (TAG) accumulation in eukaryotic microalgae without reducing cell division. In connection with this, we have recently reported that the expression of the chloroplast enzyme diacylglycerol acyltransferase 3 (DGAT3) is induced by light in concert with TAG accumulation in Chlamydomonas reinhardtii. In this work, we report the identification of two phytyl ester synthases (PES) in C. reinhardtii, named PESα and PESβ. These are homologous to chloroplast PES1 and PES2 of Arabidopsis thaliana, which play a role in the synthesis of fatty acid phytyl esters (FAPEs) and TAGs. We demonstrate that PESα and PESβ transcript levels are transiently induced upon transferring cell cultures from a growth condition of low light to high light, and this occurs in parallel to an increase in TAG levels. In a pesα knockdown mutant, DGAT3 transcripts and TAG levels are significantly higher than in the parental strain at the end of the low-light period, and remain elevated after shifting pesα cells to the high-light condition. On the contrary, in a pesβ knockdown mutant, TAG levels, as well as DGAT3 expression, are similar to those of the control strain. These results suggest that PESα and PESβ are non-redundant in TAG metabolism and that PESα is functionally related to DGAT3. Full article

Glycerol-3-phosphate acyltransferases (GPATs) catalyze the initial and rate-limiting step of glycerolipid biosynthesis, yet their contribution to salt tolerance in the soybean (Glycine max (L.) Merr.) plants remains largely uncharacterized. In this study, a total of 27 GmGPAT genes were identified, and their evolutionary relationships, chromosomal distribution, conserved motifs, and cis-regulatory elements were comprehensively analyzed. Through transcriptomic and qPCR analyses, many GmGPATs were found to be predominantly expressed in roots, with GmGPAT1, a plastid-targeted isoform, displaying the most rapid and pronounced transcriptional activation under salt stress. GFP-fusion experiments in transient expression assays confirmed plastid localization of GmGPAT1. Heterologous expression in Escherichia coli together with enzyme kinetics analyses validated its enzymatic function as a GPAT family member. The soybean hairy-root lines overexpressing GmGPAT1 exhibited enhanced root elongation, increased biomass, and improved photosynthetic efficiency under 120 mM NaCl stress, while CRISPR/Cas9 knockout mutants showed pronounced growth inhibition. Physiological assays demonstrated that GmGPAT1 overexpression mitigated oxidative damage by limiting reactive oxygen species (ROS) accumulation and lipid peroxidation, increasing antioxidant enzyme activities (CAT, SOD, POD), and elevating the ratios of AsA/DHA and GSH/GSSG. These changes contributed to redox homeostasis and improved Na⁺ extrusion capacity. A genome-wide association study (GWAS) involving 288 soybean accessions identified a single nucleotide polymorphism in the GmGPAT1 promoter that was significantly correlated with salt tolerance, and the beneficial Hap1 allele emerged as a promising molecular marker for breeding. Together, these analyses emphasize the status of GmGPAT1 as a major regulator of salt stress adaptation through the coordinated modulation of lipid metabolism and redox balance, extend the functional annotation of the soybean GPAT family, and highlight new genetic resources that can be leveraged to enhance tolerance to salt stress in soybean cultivars. Full article

Background: We have previously demonstrated that the function and expression of the Na⁺/taurocholate cotransporting polypeptide (NTCP) and the organic cation transporter 1 (OCT1) are affected by increasing free or unesterified cholesterol in the plasma membrane by an acute incubation with cholesterol for 30 min. In the current study we wanted to extend these findings to a more chronic condition to mimic what would be seen in obese patients. Methods: We incubated HEK293 cells that stably express NTCP or OCT1 for 24 h with 0.05 mM cholesterol and determined their function by measuring uptake of radioactive taurocholate or MPP⁺. Expression at the plasma membrane was quantified with a biotinylation assay combined with Western blots. Results: Incubation with cholesterol increased the cholesterol content of the cells by about 2-fold. Transport mediated by NTCP and OCT1 was decreased. Membrane expression for both transporters showed a slight decrease, and when kinetics were normalized for the membrane expression, the V_max for NTCP-mediated taurocholate uptake slightly decreased, but the V_max and the capacity (V_max/K_m) for OCT1-mediated MPP⁺ uptake increased by 2.5-fold and 3-fold, respectively. Acyl-Coenzyme A acyltransferase inhibitors enhanced the decrease in transport function, potentially due to retention of more free cholesterol in the plasma membrane. Conclusions: Chronic increases in free cholesterol in the plasma membrane can result in increased or decreased transporter function and expression. In the case of OCT1, which is involved in the uptake of the anti-diabetic drug metformin into hepatocytes, the 3-fold increase in transport capacity might affect drug therapy. Full article

Background/Objectives: Neonatal respiratory distress syndrome (NRDS) is a heterogenous respiratory illness that mainly affects preterm neonates. It is characterized by insufficient production of pulmonary surfactant and impaired lung compliance. The lysophosphatidylcholine acyltransferase 1 (LPCAT1) enzyme has a crucial function in lipid remodeling through the conversion of lysophosphatidylcholine to phosphatidylcholine, the major component of pulmonary surfactant. In this research, we aimed to investigate the association of the LPCAT1*rs9728 variant with NRDS susceptibility using hereditary analysis and bioinformatic approaches. Methods: The LPCAT1 (rs9728; c.*1668T>C) variant was characterized among 100 preterm neonates with RDS and 100 non-RDS neonates utilizing the TaqMan SNP genotyping assay. Logistic regression analysis was performed to identify the risk factors of respiratory distress syndrome. The functional mechanism of the LPCAT1 gene was elucidated using bioinformatic approaches. Results: The LPCAT1*rs9728 C/C genotype was significantly associated with a 78% reduced risk of NRDS (OR = 0.22, p = 0.027), although the minor C allele did not attain a significant finding (OR = 0.83, p = 0.416). Apgar score and Silverman–Andersen respiratory severity score (RSS) were statistically significant with prematurity classes (p < 0.05). Additionally, gestational age and birth weight were considered independent risk factors in the progression of RDS among preterm neonates. Conclusions: This research exhibited a significant difference between the LPCAT1 (rs9728; c.*1668T>C) variant and reduced risk against the development of RDS among preterm neonates. The rs9728*C/C genotype revealed a significant association with decreased risk of NRDS compared to non-RDS neonates. Full article