Search Results (322)

A synthetic methodology of the CuAAC “click” approach was exploited for the construction of 1,2-azolyltriazole quinine derivatives by the reaction of O-propargylquinine with azidomethyl-1,2-azoles in methanol. Quinine–piperidine and quinine–anabasine conjugates were obtained using a chloroacetate linker by reacting quinine chloroacetate with piperidine or anabasine in a diethyl ether medium. Cinchophene ester was obtained by the acylation of quinine with cinchophen acid chloride in methylene chloride. The antibacterial, fungicidal, analgesic and cytotoxic properties of the obtained compounds were examined. Full article

Sea buckthorn is a vital woody oil species valued for its role in soil conservation and its bioactive seed oil, which is rich in unsaturated fatty acids and other compounds. However, low seed oil content and small seed size are the main bottlenecks restricting the development and utilization of sea buckthorn. In this study, we tested the seed oil content and seed size of 12 sea buckthorn cultivars and identified the key genes and transcription factors involved in seed development and lipid biosynthesis via the integration of UID RNA-seq (Unique Identifiers, UID), WGCNA (weighted gene co-expression network analysis) and qRT-PCR (quantitative real-time PCR) analysis. The results revealed five cultivars (CY02, CY11, CY201309, CY18, CY21) with significantly higher oil contents and five cultivars (CY10, CY201309, CY18, CY21, CY27) with significantly heavier seeds. A total of 10,873 genes were significantly differentially expressed between the S1 and S2 seed developmental stages of the 12 cultivars. WGCNA was used to identify five modules related to seed oil content and seed weight/size, and 417 candidate genes were screened from these modules. Among them, multiple hub genes and transcription factors were identified; for instance, ATP synthase, ATP synthase subunit D and Acyl carrier protein 1 were related to seed development; plastid–lipid-associated protein, acyltransferase-like protein, and glycerol-3-phosphate 2-O-acyltransferase 6 were involved in lipid biosynthesis; and transcription factors DOF1.2, BHLH137 and ERF4 were associated with seed enlargement and development. These findings provide crucial insights into the genetic regulation of seed traits in sea buckthorn, offering targets for future breeding efforts aimed at improving oil yield and quality. Full article

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

The mechanism by which quorum sensing (QS) enhances stress resistance in enterohemorrhagic Escherichia coli (E. coli) O157:H7 remains unclear. We employed optimized exogenous QS signal N-acyl-homoserinelactones (AHL) (100 μM 3-oxo-C6-AHL, 2 h) in EHEC O157:H7 strain EDL933, which was validated with endogenous yenI-derived AHL, to investigate QS-mediated protection against acid stress. RNA-seq transcriptomics identified key upregulated genes (e.g., rmf). Functional validation using isogenic rmf knockout mutants generated via λ-Red demonstrated abolished stress resistance and pan-stress vulnerability. Mechanistic studies employing qRT-PCR and stress survival assays established Ribosomal Hibernation Factor (RMF) as a non-redundant executor in a SdiA–RMF–RpoS axis, which activates ribosomal dormancy and SOS response to enhance EHEC survival under diverse stresses. For the first time, we define ribosomal hibernation as the core adaptive strategy linking QS to pathogen resilience, providing crucial mechanistic insights for developing EHEC control measures against foodborne threats. Full article

Quorum quenching (QQ) is of interest for potential application as a sustainable strategy for bacterial disease control via communication interruption. The QQ enzyme can be used as a good alternative antagonist to combat antibiotic abuse and bacterial resistance. Here, genomic DNA sequencing was performed on N-acyl homoserine lactonase from the deep-sea strain Bacillus velezensis DH82 with Cluster of Orthologous Groups of proteins (COGs) annotation. The homologous sequences with β-lactamase domain-containing protein were predicted to be potential QQ enzymes and were cloned and expressed to study their quorum quenching properties by comparing them with the reported enzyme AiiA_3DHB. The experimental results of enzyme activity analysis and steady-state kinetics, as well as enzyme structure and substrate docking simulations and predictions, all consistently demonstrated that YtnP_DH82 presented superior enzyme structural stability and higher degradation efficiency of N-acyl homoserine lactones than AiiA_DH82 under the effects of pH, and temperature, and performed better on short -chain and 3-O-substituted AHSLs. The findings revealed the structural and biochemical characterization of YtnP_DH82 from the deep sea, which provide the capacity for further application in sustainable aquaculture as an alternative to antibiotics. Full article

Floridoside (2-O-D-glycerol-α-D-galactopyranoside) is a natural product typically found in red algae. It serves as the algae’s carbon reserve and is produced as a protective response against osmotic and heat stress. Both floridoside and its acylated derivatives have been associated with modulating redox homeostasis and inflammatory responses. Therefore, we aimed to evaluate whether the newly synthesized floridoside phosphotriesters (1b–1d, 1f–1h) and acylated floridoside derivative (1e) can modulate the oxidative burst in stimulated human neutrophils. Synthetic strategies included the glycosylation of the thioglycoside donor with glycerol derivatives, having NIS/TfOH as the promoter. Phosphorylation was achieved with POCl₃ in the presence of pyridine. The compounds were analysed for their cytotoxicity, with 1b and 1h being cytotoxic at 50 μM, while the others showed no cytotoxicity in the tested concentrations. The detection of the neutrophils’ oxidative burst was performed using multiple probes [luminol, aminophenyl fluorescein (APF), and Amplex Red (AR)] to evaluate reactive species levels. Compound 1e prevented the oxidative burst in activated human neutrophils (IC₅₀ = 83 ± 7 μM). All the other tested compounds were ineffective in inhibiting APF and AR oxidation under the present experimental conditions. These findings highlight the potential of floridoside-based derivatives as candidates for targeting inflammatory pathways. Full article

Aminosteroid derivative RM-581 stands out as an anticancer agent, supported by positive in vitro and in vivo studies on resistant cancers of the breast, prostate, and pancreas. A synthetic route has already been developed to obtain aminosteroid RM-581 in small quantities (scale of milligrams to a few grams). However, this route has significant limitations in view of its transposition to scaling up to larger quantities to support late preclinical and clinical trials. Among the problems are the use of toxic reagents, the moderate overall yield, and the need for multiple purifications through chromatographic columns. The development of a new synthetic route has therefore been explored. Starting from commercially available estrone, 2,4-dibromo-estrone was rapidly formed, followed by the regioselective introduction of a nitro group at the C2 position and by the methylation of phenol at the C3 position. The 4-bromo-2-nitro-3-O-methylestrone was then reduced to 2-amino-3-O-methylestrone and the primary amine was used to form the piperazine ring. Once the cyclization step was carried out, the last two steps were identical to the first synthetic route previously reported, i.e., introducing an ethynyl group at the C-17α position and then adding the quinoline-proline side chain with an N-acylation, assisted by a peptide coupling reagent. Importantly, no purification by chromatography was necessary during the whole sequence of reactions and only a final silica gel filtration, followed by recrystallization, led to RM-581 at a very high level of purity. The structure was also fully characterized by 2D NMR analysis. Full article

Background/Objectives: Nucleoside precursors and derivatives play pivotal roles in the development of antimicrobial and antiviral therapeutics. The 2022 global outbreak of monkeypox (Mpox) across more than 100 nonendemic countries underscores the urgent need for novel antiviral agents. This study aimed to synthesize and evaluate a series of 5′-O-(palmitoyl) derivatives (compounds 2–6), incorporating various aliphatic and aromatic acyl groups, for their potential antimicrobial activities. Methods: The structures of the synthesized derivatives were confirmed through physicochemical, elemental, and spectroscopic techniques. In vitro antibacterial efficacy was assessed, including minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) determinations for the most active compounds (4 and 5). The antifungal activity was evaluated based on mycelial growth inhibition. Density functional theory (DFT) calculations were employed to investigate the electronic and structural properties, including the global reactivity, frontier molecular orbital (FMO), natural bond orbital (NBO), and molecular electrostatic potential (MEP). Molecular docking studies were conducted against the monkeypox virus and the Marburg virus. The top-performing compounds (3, 5, and 6) were further evaluated via 200 ns molecular dynamics (MD) simulations. ADMET predictions were performed to assess drug-likeness and pharmacokinetic properties. Results: Compounds 4 and 5 demonstrated remarkable antibacterial activity compared with the precursor molecule, while most derivatives inhibited fungal mycelial growth by up to 79%. Structure-activity relationship (SAR) analysis highlighted the enhanced antibacterial/antifungal efficacy with CH₃(CH₂)₁₀CO– and CH₃(CH₂)₁₂CO–acyl chains. In silico docking revealed that compounds 3, 5, and 6 had higher binding affinities than the other derivatives. MD simulations confirmed the stability of the protein-ligand complexes. ADMET analyses revealed favorable drug-like profiles for all the lead compounds. Conclusions: The synthesized compounds 3, 5, and 6 exhibit promising antimicrobial and antiviral activities. Supported by both in vitro assays and comprehensive in silico analyses, these derivatives have emerged as potential candidates for the development of novel therapeutics against bacterial, fungal, and viral infections, including monkeypox and Marburg viruses. Full article

Raman spectroscopy is one of the best techniques for obtaining information concerning the physical–chemical interactions between a lipid and a solvent. Phospholipids in water are the main elements of cell membranes and, by means of their chemical and physical structures, their cells can interact with other biological molecules (i.e., proteins and vitamins) and express their own biological functions. Phospholipids, due to their amphiphilic structure, form biomimetic membranes which are useful for studying cellular interactions and drug delivery. Synthetic systems such as DPhPC-based liposomes replicate the key properties of biological membranes. Among the different models, phospholipid mimetic membrane models of lamellar vesicles have been greatly supported. In this work, a biomimetic system, a deuterium solution (50 mM) of the synthetic phospholipid 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhDC), is studied using μ-Raman spectroscopy in a wide temperature range from −181.15 °C up to 22.15 °C, including the following temperatures: −181.15 °C, −146.15 °C, −111.15 °C, −76.15 °C, −61.15 °C, −46.15 °C, −31.15 °C, −16.15 °C, −1.15 °C, 14.15 °C, and 22.15 °C. Based on the Raman evidence, phase transitions as a function of temperature are shown and grouped into five classes, where the corresponding Raman modes describe the stretching of the (C−N) bond in the choline head group (gauche) and the asymmetric stretching of the (O−P−O) bond. The acquisition temperature of each Raman spectrum characterizes the rocking mode of the methylene of the acyl chain. These findings enhance our understanding of the role of artificial biomimetic lipids in complex phospholipid membranes and provide valuable insights for optimizing their use in biosensing applications. Although the phase stability of DPhPC is known, the collected Raman data suggest subtle molecular rearrangements, possibly due to hydration and second-order transitions, which are relevant for membrane modeling and biosensing applications. Full article

Methoxycamalexins are close structural derivatives of the indolic phytoalexin Camalexin, which is a well-known drug lead with an antiproliferative and antioxidant profile. 6-methoxycamalexin, 7-methoxycamalexin, and 6,7-dimethoxycamalexin are natural bioactive products, and there is significant interest in the development of efficient methods for the synthesis of structurally related analogues. Herein, we describe an efficient and high-yielding method for the synthesis of variously substituted hydroxy-, bezyloxy, and methoxycamalexins. A set of methoxy-, hydroxy-, and benzyloxy-indoles were successfully amidoalkylated with N-acyliminium reagents derived in situ from the reaction of thiazole or methylthiazoles with Troc chloride. Eleven novel N-acylated analogues were synthesized, with yields ranging from 77% to 98%. Subsequent oxidative reactions with o-chloranil or DDQ led to 10 novel oxy-camalexins in 62–98% yield. This two-step approach allowed the synthesis of two 4,6-dimethoxy camalexins, which are difficult to obtain using published methods. The structure of the obtained products was unequivocally determined by ¹H-, ¹³C{¹H}-, HSQC-NMR, FTIR, and HRMS spectral analyses. An in silico assay was carried out on the obtained products to assess their general toxicity and physicochemical properties, including their compliance with Lipinski’s rule of five. The results indicate that all compounds have good potential to be developed as drugs or agrochemicals. Full article

Cyanidin-3-O-glucoside (C3G) was used as a substrate for enzymatic acylation, and different compounds (methyl n-octanoate and methyl salicylate) were selected as acyl donors. Structural analysis (UV–Vis, FTIR, and HPLC) revealed the successful integration of methyl ester compounds into the structural units of C3G. The thermostability and photostability of acylated C3Gs, particularly those with methyl salicylate as the acyl donor, exhibited significant improvements. The molecular geometries of the different anthocyanins were optimized using computational chemistry, and energy level calculations were performed by using Density Functional Theory (DFT) to identify the antioxidant active site. Then, the antioxidant properties of C3G and acylated C3Gs (O-C3G and S-C3G) were studied in both aqueous and lipid systems. In aqueous systems, acylated C3Gs exhibited higher antioxidant properties than C3G in DPPH radical scavenging and hydroxyl radical scavenging assays, with cyanidin-3-O-glucoside salicyl acyl product (S-C3G) demonstrating the highest activity. However, the antioxidant properties varied in lipid systems. In lipid systems, acylated C3Gs displayed better antioxidant properties than C3G in POV and TBARS assays, with cyanidin-3-O-glucoside n-octanoate acid acyl product (O-C3G) showing better antioxidant properties compared to that in aqueous systems. Full article

Background/Objectives: Seminolipid (sulfogalactosylglycerolipid (SGG)) is abundantly present on the sperm surface and its roles in sperm–egg interaction are well-documented. SGG liposomes have direct affinity for the zona pellucida (ZP), the egg extracellular matrix. SGG is also integral to the formation of sperm lipid rafts, which are platforms on the sperm surface for ZP binding. Our objective was to chemically synthesize a short-chain analog of SGG (SC-SGG with a C6 acyl chain instead of C16 in the natural lipid), which is solubilized in an aqueous environment, and to determine the inhibitory effects of SC-SGG in mouse sperm–egg interaction, and thus fertilization. Methods: SC-SGG was synthesized from a 3-O-galactopyranosyl-sn-glycerol intermediate protected on the sugar moiety through the acylation of glycerol with caproic acid, deprotection and regioselective 3-O-sulfation of the galactose residue. SC-SGG solubilized in a medium was used to treat sperm–egg co-incubates or to pretreat sperm or eggs before co-incubating sperm with eggs or vice versa. Sperm–ZP binding and fertilization (scoring eggs with two pronuclei) were microscopically assessed. Results: SC-SGG was efficiently synthesized with a 78% overall yield. SC-SGG inhibited sperm–ZP binding and fertilization of mouse gametes in a concentration-dependent manner, and at 6 µM SC-SGG, the mouse fertilization was zero. SC-SGG inhibited the fertilizing ability of both sperm and eggs, as shown in the pretreatment experiments. Conclusions: SC-SGG was an effective inhibitor of mouse fertilization in vitro. It warrants development to be a non-hormonal contraceptive. Full article

The enhancement of enzyme activity has garnered significant attention in biotransformation processes and applications. This enhancement is achieved through the use of specific nanomaterials (NMs) with unique physicochemical characteristics responsive to external stimuli. In this study, an enzyme–Fe₃O₄ nano-biocatalytic system (NBS) was developed to enable real-time activation of enzymatic catalysis under alternating magnetic field (AMF) and near-infrared (NIR) irradiation using dual-functional Fe₃O₄ magnetic nanoparticles (MNPs). When exposed to an AMF, Fe₃O₄ MNPs generate molecular vibrations through mechanisms such as Néel or Brown relaxation while acting as a photothermal agent in response to NIR irradiation. The synergistic effect of AMF and NIR irradiation significantly enhanced energy transfer between the enzyme and Fe₃O₄ MNPs, resulting in a maximum 4.3-fold increase in enzyme activity. Furthermore, the system reduced aldol reaction time by 66% (from 4 h to 1.5 h) while achieving 90% product yield. Additionally, factors such as nanoparticle size and NIR power were found to play a critical role in the efficiency of this real-time regulation strategy. The results also demonstrate that the enzyme–Fe₃O₄ nanocomposites (NCs) significantly enhanced catalytic efficiency and reduced the reaction time for aldol reactions. This study demonstrates an efficient NBS controlled via the synergistic effects of AMF and NIR irradiation, enabling spatiotemporal control of biochemical reactions. This work also provides a breakthrough strategy for dynamic biocatalysis, with potential applications in industrial biomanufacturing, on-demand drug synthesis, and precision nanomedicine. Full article

The knowledge of the routes of excretion of the toxins accumulated by molluscs is a key step in designing methods that accelerate depuration. In this work, the excretion route, in mussels and cockles, of the main diarrhetic shellfish poisoning (DSP) toxins in Europe (okadaic acid and dinophysistoxin-2) after natural intoxication were studied. During depuration, the amounts of free toxins and their derivatives were quantified in bivalves, faeces, and water. Most toxins (>98%) were excreted through faeces as acyl derivatives (most likely 7-O-acyl esters), independent of the ratio between these derivatives and free toxins in soft tissues. The small proportion of toxins excreted into water mostly constituted the free forms of the toxins. Both species shared the same route even though they contained very different proportions of free toxins in their soft tissues. No substantial changes in this general pattern were observed during the experiment. The esters of fatty acids with 16 carbon atoms were the most abundant in both soft tissues and faeces, but they were not the same in mussels and cockles. Most of the variability in ester proportions can be attributed to the species more than to their differential excretion (water or faeces) suggesting that there are not large differences in the depuration of the different esters. Full article

Ghrelin is a 28 amino acid peptide hormone that impacts a wide range of biological processes, including appetite regulation, glucose metabolism, growth hormone regulation, and cognitive function. To bind and activate its cognate receptor, ghrelin must be acylated on a serine residue in a post-translational modification performed by ghrelin O-acyltransferase (GOAT). GOAT is a membrane-bound O-acyltransferase (MBOAT) responsible for the catalysis of the addition of an octanoyl fatty acid to the third serine of desacyl ghrelin. Beyond its canonical role for ghrelin maturation in endocrine cells within the stomach, GOAT was recently reported to be overexpressed in prostate cancer (PCa) cells and detected at increased levels in the serum and urine of PCa patients. This suggests GOAT can serve as a potential route for the detection and therapeutic targeting of PCa and other diseases that exhibit GOAT overexpression. Building upon a ghrelin mimetic peptide with nanomolar affinity for GOAT, we developed an antibody-conjugate-inspired system for customizable ligand-conjugate (LC) synthesis allowing for the attachment of a wide range of cargoes. The developed synthetic scheme allows for the easy synthesis of the desired LCs and demonstrates that our ligand system tolerates an extensive palette of cargoes while maintaining nanomolar affinity against GOAT. Full article