Thermotropic nematic liquid crystals (LC) are orientationally ordered liquids composed of mesogenic molecules that become isotropic liquids at the nematic-isotropic transition temperature (TNI), at which the order disappears. Dissolving a nonmesogenic substance in an LC usually produces a disruption of the molecular order that leads to a decreasing of the TNI. However, some nonmesogenic substances enhance the molecular order, yielding increments of the TNI. Rigid aromatic carboxylic acids like benzoic acid possess this order-enhancing capacity due to the formation of elongated dimers, which align with the uniaxial nematic environment. In the present research, the thermodynamics of the dimerization of 20 substituted benzoic acids dissolved in the nematic LC 4-n-pentyl-4'-cyanobiphenyl (5CB) and the phase behavior of the mixtures were assessed. The substituents include amino, fluoro, chloro, bromo, iodo, and nitro groups linked to the aromatic ring of the benzoic acid at ortho, meta, and para positions. Both the geometry and the electron-withdrawing or donating effect of the substituent have an influence on the ordering capability of the substituted benzoic acid. In general, electron-donating groups at the para position in benzoic acids have a large order-enhancing power. Electron-withdrawing groups promote the ionization of the substituted benzoic acids, limiting the dimerization capability of these dopants. Regarding the substitution position of the groups, the para substitutions lead to the formation of long and slim calamitic dimers with a large aspect ratio length/diameter. These calamitic dimers align with the nematic solvent and act as scaffolds in the uniaxial solvent. The nematic LC mixtures were analyzed by polarized optical microscopy, differential scanning calorimetry, and infrared spectroscopy. Theoretical calculations aided to ascertain the most probable dimers in amphoteric dopants like aminobenzoic acids. A thermodynamic model was developed to analyze the nematic-isotropic transitions. Two dopants, 4-aminobenzoic acid and 4-N-methylaminobenzoic acid, exhibit extraordinary order-enhancing power, yielding increments of the nematic-isotropic transition temperature up to 12 K with minor concentration of the dopants.

Despite its wide use in the past, the UVB filter p-aminobenzoic acid (PABA) is currently considered unsafe in the cosmetic industry. Among other reasons, there is the claimed formation of photoadducts with the nucleobases in DNA. We provide theoretical evidence showing the spontaneous intercalation of PABA in a (dAdT)6·(dAdT)6 strand. The π-π stacking interactions between PABA and the nucleobases result in an effective coupling of the native excited states of both molecules, altering the optical properties of DNA. Transition density matrix analysis shows that although the absorption spectrum of the DNA-PABA complex is dominated by excitons, the dark charge-separated states, which have been associated with photodamaging radical reactions in the literature, are overall more numerous in the entire absorption energy range. We show that PABA → DNA charge transfer states are more abundant, more energetically accessible, and potentially longer-lived than those across nucleobases, hence explaining the radicallic origin of the photoadducts between the filter and DNA.

3‑Hydroxyanthranilic acid (3‑HAA) and quinolinic acid (QA) are central metabolites of the kynurenine pathway with broad biomedical and industrial relevance, yet their microbial production remains limited by long pathways and rate-limiting enzymes. Here, we report the rational design and validation of a non‑natural shortcut pathway enabling de novo biosynthesis of 3‑HAA and QA in Escherichia coli. The pathway begins from anthranilic acid (AA), a chorismate‑derived intermediate that can be efficiently overproduced. Regioselective 3-hydroxylation of AA was achieved using an FAD-dependent monooxygenase HpaH from Geobacillus thermodenitrificans, supported by a dedicated FAD reductase (GTNG_3158) essential for efficient cofactor regeneration. The resulting 3‑HAA was subsequently converted to QA through oxidative ring cleavage by NbaC from Pseudomonas fluorescens, followed by spontaneous cyclization. Through enzyme expression tuning, precursor availability enhancement, and fermentation optimization, the engineered strains produced 2.17g/L 3‑HAA and 2.04g/L QA from glucose in shake flasks, representing the highest reported microbial 3‑HAA titer and demonstrating the efficient extension of the artificial pathway to QA production. This work establishes a concise and productive biosynthetic strategy, enabling sustainable and high‑level microbial production of 3-HAA‑derived compounds.

Acute myeloid leukemia (AML) exhibits metabolic reprogramming that supports immune evasion and treatment resistance. The kynurenine pathway (KP) is a key regulator of tumor-immune interactions, yet its downstream organization and clinical relevance in AML remain unclear. Here, we combined in vitro models with patient serum profiling to determine whether KP branching patterns are associated with treatment response. Extracellular KP metabolites were quantified in AML cell lines (HL-60 and MOLM-14) following induction regimens, and quantified circulating KP metabolites in patient serum samples collected from AML patients before and after induction therapy. Treatment was associated with normalization of tryptophan depletion and kynurenine accumulation in responders, indicating partial restoration of systemic KP homeostasis. Notably, baseline (pre-treatment) samples from patients who were later classified as non-responders exhibited a distinct metabolic phenotype characterized by persistent kynurenine elevation, increased anthranilic and kynurenic acid levels, and enrichment of 3-hydroxykynurenine flux, suggesting preferential engagement of oxidative and immunomodulatory KP branches. Among evaluated metabolic indices, the 3-hydroxykynurenine-to-kynurenine ratio demonstrated the strongest discriminatory capacity for distinguishing response to induction therapy (DA: daunorubicin + cytarabine; DAC: daunorubicin + cytarabine + cladribine), outperforming individual metabolite measurements and highlighting functional pathway flux rather than absolute metabolite abundance as a determinant of clinical outcome.

Catalytic synthesis of dihydroavenanthramide D by lipase RWL

Carbon quantum dots (CQDs) have emerged as a versatile nanoplatform for biomedical application owing to their tunable physicochemical properties. In this context, microwave strategy was applied for the first time to synthesize N-CQDs under uniform dielectric heating of 360 W, using readily available organic molecules, namely meta-toluidine, meta-aminophenol and meta-aminobenzoic acid. The novelty of the work was to study the effect of variation of single functional-group at the meta-positions on the surface polarity and charge density for the production of N-CQDs. Out of three precursors, the meta-aminobenzoic acid-derived CQDs manifested the highest degree of aqueous dispersibility with average particle size of around 4–6 nm, and were thus selected for further study. The as synthesized CQDs from meta-aminobenzoic acid was conjugated to doxorubicin at different drug concentrations and MTT assay was carried out using HeLa cells to assess the effectiveness of the CQD-doxorubicin conjugate and free drug. MTT assay revealed 74.47 ± 2.45% and 65.73 ± 4.61% cytotoxicity of the CQD-doxorubicin conjugate and the free drug, respectively against HeLa cells at the highest drug concentration of 12 µg/ml, presumably owing to facilitated endocytic uptake of the conjugate over the free drug by the HeLa cells.

The present study engineered a bioactive seed coating based on molecularly optimized chitosan-salicylic acid (SA-CS) networks to fortify folate biosynthesis in wheat seedlings. Among tested phytohormones, salicylic acid (SA) promoted seedling growth, folate accumulation, and antioxidant capacity. Composite coatings were fabricated using chitosan of varying molecular weights; films formulated with 0.3% medium molecular weight chitosan and 0.1% SA (SA-MCS) exhibited moderate water vapor permeability and sustained release, creating a favorable microenvironment for germination. SA-MCS coatings significantly increased total folates from 569.87 to 702.75 μg 100 g-1 DW. Mechanistically, controlled SA delivery upregulated GTP cyclohydrolase 1 (GCH1) and aminodeoxychorismate synthase (ADCS), accelerating metabolic flux into the pterin and para-aminobenzoic acid (pABA) branches. Multiomics analysis revealed coordinated mobilization of carbon units from histidine catabolism and glutamate into one-carbon metabolism, providing structural backbones and methyl groups for folate enrichment. These findings demonstrate SA-CS coatings as an efficient, biodegradable seed delivery platform for eco-friendly folate biofortification.

Carbon quantum dots (CQDs) were synthesized via a green, bottom-up approach from tomato biomass, using stems and fruits as distinct carbon precursors. To tailor their surface chemistry and optical response, m-aminobenzoic acid was used as a nitrogen-containing dopant during synthesis. The resulting CQDs form colloidally stable, nanoscale aggregates in aqueous media and exhibit strong excitation-dependent photoluminescence, with maximum emission under excitation at 300 and 370nm. Comprehensive structural and surface analyses reveal that precursor origin significantly influences defect density, hybridization states, and functional group distribution, directly governing luminescent behavior. Both fruit-derived and stem-derived CQDs display efficient fluorescence quenching upon coordination with Cu²⁺ ions, enabling sensitive detection with limits of detection of 0.059 µM and 0.048 µM, respectively. The enhanced sensing performance is attributed to surface-accessible oxygen- and nitrogen-containing functional groups that promote strong metal-ligand interactions. This work demonstrates a sustainable and low-cost strategy for converting agricultural waste into functional nanomaterials, while highlighting the critical role of biomass composition and surface chemistry in tuning CQD photophysics and metal-ion sensing capabilities.

Antimicrobial activity of bis(4-carboxyanilinium) selenate and its interaction with synthetic liposomes: A biophysical, molecular docking and molecular dynamics study.

Brinzolamide (BRZ) is a selective carbonic anhydrase inhibitor recommended for the topical treatment of primary open-angle glaucoma. Despite its promising therapeutic characteristics, BRZ has significant limitations of low water solubility and poor dissolution. To address these challenges, we developed a BRZ co-crystals with p-aminobenzoic acid (PABA). A synthesized BRZ-PABA binary system was characterized by FTIR, Powder XRD, SEM and thermogravimetric analysis. Spectroscopic characterization suggests the presence of intermolecular interactions indicative of a potential new solid phase BRZ-PABA cocrystal. Saturation solubility results revelled that F7 showed a 115.35% and 208.45% improvement in solubility in water and STF, respectively. Similarly, the improvement in dissolution (80.30 % improvement in T50) is shown. The ex vivo permeability showed enhanced permeation rate of BRZ through F7 (411.3 ± 12.72 μg/h) compared to the marketed formulation (364.12 ± 9.26 μg/h) and free drug (313.89 ± 6.35 μg/h). Also, the co-crystals of BRZ showed a good ocular tolerability and comparatively stronger IOP-reducing effect and a faster recovery toward normal values. Thus, the reported co-crystals have significant implications for employing a co-crystallization strategy to enhance BRZ permeability and efficacy in the pharmaceutical domain. Additionally, findings underscored the growing significance of pharmaceutical co-crystals in drug development.

Deeper understanding of advanced oxidation processes: identification/quantification of different oxidants in mono and binary mixtures using an orthogonal luminescent/optical approach.

Sodium-glucose cotransporter 2 inhibitors, such as empagliflozin (EMPA), have been increasingly investigated for their potential neuroprotective properties, but their overall metabolic impact in Parkinson's disease (PD) remains incompletely understood. Using a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD, we investigated the effect of EMPA on tryptophan (TRP) metabolism, neurotransmitter levels and antioxidant markers in the striatum. Targeted ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was used for metabolite quantification. Pairwise group differences were assessed using Welch's two-sample t-test, with false discovery rate correction, and multivariate analyses were applied for exploratory pattern recognition. EMPA treatment significantly enhanced the neuroprotective arm of the kynurenine pathway (KP), increasing kynurenic acid (KA), anthranilic acid (AA), xanthurenic acid (XA) and the corresponding enzymatic activity ratios in MPTP-induced PD animals. The selective elevation of the KA/TRP ratio without a corresponding change in KYN/TRP suggests that EMPA acts specifically on the KAT-mediated neuroprotective branch, potentially through restoration of astrocytic redox state in the striatum, rather than through generalized modulation of IDO/TDO-driven TRP catabolism. In Sirtuin3 knock-out (S3KO) mice, EMPA reduced 3-hydroxykynurenine (3OHK) levels and the Oxidative Stress Index (3OHK/(KA + AA + XA)), and improved glutathione redox status, as reflected by reduced GSSG levels and an improved GSH/GSSG ratio. These results demonstrate that EMPA exerts significant neurometabolic effects in a mouse model of PD, shifting KP flux towards neuroprotective metabolites and improving redox homeostasis-particularly in the context of mitochondrial dysfunction modelled by Sirtuin3 deficiency. Future studies extending these findings to additional experimental models and clinical settings will be essential to fully elucidate the translational potential of EMPA in neurodegeneration.

Syntheses, crystal structures, theoretical insights and DNA (1BNA) docking studies of 3-(3-oxo-1,3-dihydroisobenzofuran-1-yl)aminobenzoic acid and its metal complexes

Dual-driven magnetic nanocomposites enabling universal adsorption of perfluorocarboxylic acids (PFCAs) across ultrashort to long chains.

BackgroundCivet-digested coffee originates from the feces of civets that consume coffee cherries, where microbial fermentation in the gastrointestinal tract imparts distinctive flavor attributes, thereby enhancing its global reputation and market value. Gut microbiota is considered important drivers of coffee-bean fermentation, potentially shaping the unique and region-specific flavor characteristics of civet-digested coffee. To address this context, the present study integrated metagenomic and metabolomic analyses to compare the gut microbiota and secondary metabolites involved in coffee-bean fermentation inside Vietnamese civets.MethodsFecal samples were collected under two dietary conditions: a standardized one containing 20% protein, 6% fiber, and 0.4–1.5% lysine, and the same diet supplemented with coffee cherries. Metagenomic 16S rRNA sequencing and untargeted ultra-performance liquid chromatography quadrupole time-of-flight (UPLC-QTOF) revealed clear differences between the two groups.ResultsIntegrated metagenomic and metabolomic analyses revealed clear distinctions between the two groups. Civets on the coffee-cherry diet exhibited higher microbial diversity at the family and genus levels. Specifically, among 31 classified bacterial genera showing a trend toward significant differences in abundance, Enterococcus and Escherichia/Shigella decreased, whereas Gluconobacter, and Pseudomonas increased following the diet shift. Metabolomic profiling identified 46 metabolites across both ionization modes, and strong correlations were observed between microbial genera and metabolite profiles. Specifically, 6-hydroxyangolensic acid methyl ester, 4-aminobenzoic acid and caffeine were more abundant in civets on a coffee-cherry diet, meanwhile the other nine metabolites were more prevalent in the normal diet. Overall, the findings demonstrate that civet gut microbiota and metabolic output were highly responsive to dietary inputs, and that coffee cherries promoted a unique fermentation environment. This represents the first integrative metagenomic and metabolomic study of civets consuming coffee in Vietnam, providing valuable insights into microbial contributions to coffee fermentation.

The clubroot pathogen Plasmodiophora brassicae has an effector protein that can methylate the plant defense compound salicylic acid (SA), and the protein sequence is highly conserved in different isolates worldwide. Sequencing the full-length cDNA of P. brassicae Benzoic acid/Salicylic acid Methyltransferase (PbBSMT) from a small collection of clubs indicated the occurrence of a natural variation that differs by 18 amino acids, which was also found within the worldwide data collection for P. brassicae isolates. A search for more possible substrates including defense-inducing compounds revealed that PbBSMT was also able to convert a recently reported inductor of systemic defense, N-hydroxy pipecolic acid (NHP), to its methyl ester. PbBSMT showed much lower Km values for the substrates SA and NHP compared with the other two natural compounds previously identified to be methylated with high activities (benzoic and anthranilic acids), suggesting they are the most favored substrates in vitro. The two variants showed no difference in terms of being able to accept the four naturally occurring substrates. Mature clubs incubated for 21 d after inoculation with NHP or SA showed in vivo conversion to their respective methyl esters. The methyl ester of NHP was specifically detected in transgenic plants overexpressing PbBSMT under inductive conditions. Transgenic Arabidopsis with elevated NHP levels had reduced club weights, but no reduction in infection rate or disease severity was seen in these plants, or in mutants with decreased NHP levels. Treatment of infected plants with NHP did not reduce disease severity, and therefore a major function for NHP in defense against the clubroot pathogen is not apparent.

Study on the behavioral and metabolic response mechanisms of Peronia verruculata to marine heatwaves.

The rapid emergence of antimicrobial resistance (AMR) has become a global threat, limiting the clinical effectiveness of the drugs against microbial infections. As Methicillin-resistant Staphylococcus aureus (MRSA) and Extensively drug-resistant (XDR) Escherichia coli continue to evolve rapidly, it is critical to develop novel therapeutic agents and structurally unique antibacterial medicines. The selective bacterial folate biosynthesis pathway, which includes dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR), represents an attractive therapeutic target; however, the alarming rise of microbial sulfonamides necessitates the development of novel inhibitors. Sulphonamide antibiotics are analogues of p-aminobenzoic acid (PABA), which serves as a substrate for folate biosynthesis. Taking this into account, we developed novel PABA-imidazole analogues to combat antimicrobial resistance. In this study we designed and synthesized seven novel PABA analogues and characterized them by various spectroscopy techniques. These synthesized PABA analogues show comparatively better efficiency against both the Gram-positive (S. aureus and S. pyogenes) and Gram-negative (E. coli and P. aeruginosa) strains. Furthermore, they also show potential activity against MRSA and XDR E. coli. The DHPS/DHFR enzyme assay demonstrated that the SB2 compound suppresses the sulfamethoxazole (SUL) in DHPS inhibition, and the SB5 compound shows comparatively increased DHFR inhibitory activity compared to the trimethoprim (TMP). These results have been validated by molecular dynamics simulations and free energy analyses. In addition, the lead compounds also showed strong antioxidant activity, low cytotoxicity, and good DNA nicking behaviour, which supports their therapeutic potential.

Screening and application of high-folate-producing lactic acid bacteria in yogurt products.

Long-term trends and patterns of legacy and emerging cosmetic UV filters in German waters.