Search Results (606)

4′-Hydroxymethoxychalcones represent structurally diverse chalcone derivatives that are attractive substrates for microbial functionalization; however, the impact of methoxy substitution position on their cascade biotransformation by fungi remains poorly understood. In this study, three regioisomeric 4′-hydroxymethoxychalcones, featuring ortho-, meta-, or para-methoxy groups on ring B, were transformed using eight entomopathogenic fungal strains belonging to the genera Beauveria, Isaria, and Metarhizium. Metabolic profiles were monitored over a 10-day period using ultra-high-performance liquid chromatography coupled with diode-array detection (UHPLC-DAD), and the structures of the major products were elucidated primarily by one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and further supported by high-resolution electrospray ionization quadrupole time-of-flight mass spectrometry (HR-ESI-QTOF-MS). The investigated microorganisms catalyzed multistep transformations encompassing the reduction of the α,β-unsaturated carbonyl system, methylglucosylation, O-demethylation, and the formation of secondary polar metabolites. Although ene-reduction constituted the predominant initial reaction for all substrates, the relative distribution of subsequent metabolites varied depending on both the fungal strain and, to a lesser extent, the position of the methoxy group. The ortho-methoxy derivative exhibited the highest propensity for O-demethylation; the meta-substituted substrate generated the most heterogeneous secondary metabolite profiles, whereas the para-methoxy analogue showed the most consistent accumulation of methylglucosylated dihydrochalcones. These findings indicate that methoxy substitution position does not alter the common core biotransformation pathway, but can modulate the relative efficiency of individual steps and the extent of secondary metabolism. Full article

Microbial extracellular pigments are renewable colorants for sustainable textile dyeing. A yellow-pigment-producing fungal strain, H-1, isolated from spalted wood, was identified as Chaetomium globosum and evaluated for pigment production, characterization, stability, bioactivity, and wool dyeing. Stepwise single-factor screening indicated suitable culture conditions of initial pH 7, 25 °C, 10 d, 25 g/L glucose, 7 g/L fish peptone, and 0.25 g/L K₂HPO₄. Fourier-transform infrared spectroscopy (FTIR) revealed hydroxyl, aromatic, and C-O-C groups, and ultra-high-performance liquid chromatography-high-resolution tandem mass spectrometry (UHPLC-HRMS/MS) putatively annotated representative components including Chaetomugilin D and Armochaetoglobin G. The crude pigment produced preliminary inhibition zones of 14.30 ± 0.04 and 10.01 ± 0.17 mm against Staphylococcus aureus and Escherichia coli, respectively, while crude fermentation filtrates showed measurable hydroxyl and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacities under fixed assay conditions. The pigment was more stable under neutral to alkaline pH and short-term heating at 40–100 °C. Wool showed higher dye affinity than cotton, linen, and silk. Response surface methodology (RSM) optimized wool dyeing at pH 2.35, 91 °C, 80 min, and 2.04 g/L potassium aluminum sulfate, yielding a color strength (K/S) value of 11.65. After three dye-bath reuse cycles, K/S decreased by 16.28%, and washing/rubbing fastness remained above grade 3 under GB/T tests. These results support further development of Chaetomium globosum H-1 extracellular pigments for natural wool coloration and dye-bath reuse. Full article

Selenium is an essential trace element in the body, and supplementing it in production can improve egg quality. Sixty healthy 48-week-old Hy-Line Brown laying hens were randomly assigned to two groups. In this study, the effects of dietary selenomethionine (SeMet) supplementation on the multi-dimensional characteristics of eggshell, egg white, and egg yolk were investigated, including their mechanical properties, mineral distribution, amino acid composition, microstructure, secondary structure, fatty acid composition, and lipidomic profiles. The results showed that compared with the control group (C-group), the air chamber height and egg shape index of the SeMet group (Se-group) were decreased by 21.51% and 1.54%, respectively, after 42 days of feeding. The Haugh units, eggshell strength, and eggshell color of the Se-group were increased by 10.21%, 29.24%, and 31.26%, respectively. This work leverages advanced analytical techniques for systematic sample characterization, including Fourier-transform infrared (FTIR) spectroscopy, cryogenic scanning electron microscopy (Cryo-SEM), and high-resolution tandem mass spectrometry-based lipidomics. Adding SeMet can increase the essential amino acid content and the total content of saturated and unsaturated fatty acids in egg yolk and egg white, thereby maintaining excellent protein patterns and reducing lipid hydrolysis in egg yolk. However, the addition of SeMet did not significantly affect the protein secondary structure or microstructure of egg yolk and egg white. Full article

The photocatalytic degradation of Acid Orange 7 (AO7) in aqueous solution in the presence of exfoliated C₃N₄ (n-C₃N₄) as a photocatalyst was investigated under simulated solar light irradiation. The n-C₃N₄ photocatalyst was synthesized by polymerization of urea as a precursor and characterized by UV/Vis and FTIR spectroscopy, and transmission electron microscopy. Degradation products were identified by high-performance liquid chromatography with high-resolution mass spectrometry (LC–HRMS). It was found that AO7 undergoes a series of oxidation steps mediated by radicals generated during light absorption by n-C₃N₄, as well as through a photosensitization process initiated by light absorption by AO7. This results in decolorization and the formation of aromatic and aliphatic intermediates, which undergo further oxidation to simpler compounds. Full article

In contrast to honeybees, the Australian stingless bee Tetragonula carbonaria appears to be robust against microbial pathogens. Streptomyces sp. 127Q, isolated from T. carbonaria, inhibited the growth of Lysinibacillus sphaericus, which is the only microorganism reported to affect T. carbonaria. The antimicrobials were purified from Streptomyces sp. 127Q by bioassay-guided isolation using ethyl acetate extraction and Diaion HP20 chromatography, followed by reverse phase HPLC fractionation. The antimicrobial compounds were identified by high-resolution mass spectrometry, UV-Vis-spectroscopy, nuclear magnetic resonance spectroscopy, and genome mining as new members of the trioxacarcin/gutingimycin family having a 1,2-dihydroxyanthraquinone aromatic core structure. A closely related gutingimycin with a 1,2-dihydroxyanthraquinone moiety was previously observed in a crystallisation experiment of trioxacarcin A with an oligonucleotide. Streptomyces sp. 127Q produces a wide range of trioxacarcins/gutingimycins. At the onset of trioxacarcins production, Streptomyces sp. 127Q appeared to rapidly convert trioxacarcin epoxides with water, guanine, and nicotinic acid. The 1,2-dihydroxyanthraquinone trioxacarcins, trioxacarcin 692 and trioxacarcin 780, inhibited L. sphaericus with minimal inhibitory concentrations (MICs) of 37.5 μM and 75 μM, respectively. The MIC against Escherichia coli and Staphylococcus aureus was 75 μM and 150 μM, respectively. In the photoantimicrobial screening, the MIC for trioxacarcin 692 against E. coli and S. aureus decreased by 8-fold, and for trioxacarcin 780 by 4-fold. Following light pretreatment, trioxacarcin 692 (9.4 μM) inhibited E. coli and S. aureus at concentrations comparable to those of the established antibiotics ciprofloxacin and vancomycin. Neisseria gonorrhoeae was only inhibited at an MIC of ca. 18.8 μM after light preincubation. The 1,2-dihydroxyanthraquinone trioxacarcins constitute powerful antimicrobial compounds belonging to the trioxacarcin/gutingimycin family. Full article

To fully explore the metabolites of the mangrove endophytic fungus Penicillium janthinellum HDN13-309, which can produce Epipolythiodioxopiperazine (ETP) compounds with noteworthy anti-tumor activities, HPLC-MS analysis was applied, and five new gliovirin-like alkaloids, penicisulfuranols G–K (1–5), were target-directed acquired. Furthermore, penicisulfuranols G (1) and H (2) were distinguished by a double bond between C-5/C-6 and ortho-hydroxylation of C-7/C-8 on the 1,2-oxazadecaline moiety. Their structures, including absolute configurations, were elucidated based on NMR spectroscopy, ECD measurements, and high-resolution mass spectrometry, as well as by comparison with the literature. Penicisulfuranols I–K (3–5) showed promising cytotoxicity against four tumor cell lines (HCT116, HeLa, HL-60, and K562) with IC₅₀ values ranging from 0.1 to 9.9 μM. Full article

The detection of microplastics (MPs) and nanoplastics (NPLs) in biological samples is critical for understanding their environmental distribution and investigating human exposure, bioaccumulation and their potential health effects. This review provides an overview of current approaches used to detect plastic particles in in vitro and in vivo studies, focusing on microscopic, spectroscopic, spectrometric, chromatographic and flow-cytometry-based methods. Microscopy techniques, including optical, confocal, fluorescence, scanning electron (SEM), transmission electron (TEM), cryogenic electron (cryo-EM), and atomic force microscopy (AFM), enable the visualization and characterization of MPs and NPLs. Spectroscopic approaches, such as Fourier transform infrared (FT-IR) and Raman spectroscopy, are widely employed for polymer identification through characteristic molecular fingerprints. Spectrometric techniques, including single-cell inductively coupled plasma mass spectrometry (scICP-MS) and single-cell inductively coupled plasma time-of-flight mass spectrometry (scICP-TOFMS), provide sensitive elemental analyses, while flow cytometry offers high-throughput particle detection. Chromatographic approaches, particularly double-shot gas chromatography–mass spectrometry (Py-GC/MS), enable sensitive and specific polymer characterizations. Recent technological advances, including automated and high-resolution analytical approaches, are also discussed together with practical considerations for selecting appropriate methods according to the sample type and analytical objective. Collectively, these methods contribute to the assessment of plastic particle occurrence, bioaccumulation, and biological effects, supporting future environmental monitoring, human biomonitoring and risk assessment. Full article

Background: Biotrauma from invasive mechanical ventilation (IMV) and extracorporeal membrane oxygenation (ECMO) drives systemic inflammation, metabolic dysregulation, and organ dysfunction in critically ill patients. Therefore, this study aimed to identify clinical and metabolomic features associated with ICU mortality in patients receiving IMV or ECMO, as these remain incompletely characterized. Methods: The retrospective analysis included 30 ICU patients on IMV and 22 on ECMO. Metabolomic and proteomic profiling were performed using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-HRMS), and serum spectral analysis by Fourier-transform infrared spectroscopy (FTIRS). Significant variables were incorporated into multivariate logistic regression models, ranked by AIC, AUC, and statistical significance. Model performance was evaluated using stratified 5-fold cross-validation. Final models were adjusted for relevant demographic and clinical covariates. Results: The IMV cohort showed discriminatory FTIRS wavenumbers across all preprocessings, and 155 metabolites plus 14 proteins were significantly altered, with unadjusted models achieving mean AUCs above 0.9. The ECMO cohort showed discriminatory FTIRS wavenumbers in one preprocessing, and 15 metabolites plus 3 proteins were highlighted. FTIRS, metabolomic, and proteomic models reached mean AUCs of 0.967, 0.867, and 0.783, respectively, with lower stability during cross-validation. Adjustment for demographic and clinical covariates reduced model robustness. Conclusions: Stronger and more reproducible molecular signatures related to ICU mortality were observed in the IMV cohort, whereas the ECMO cohort showed reduced model stability, likely reflecting increased biological heterogeneity and small sample size. These findings support the utility of integrated omics for characterizing critical illness and outcome stratification, while reinforcing the need for validation in larger and independent cohorts. Full article

X-ray reflection spectroscopy provides one of the most effective electromagnetic routes to measuring the dimensionless spin parameter of accreting black holes. The method has produced spin constraints for both stellar-mass black holes in X-ray binaries and supermassive black holes in active galactic nuclei, and it is central to the science objectives of present and future X-ray telescopes. At the same time, this method is vulnerable to a set of coupled observational and modeling systematics: continuum-reflection degeneracy, insufficient passband, unresolved distant reflection or absorption, detector effects, source variability, accretion-state dependence, and assumptions built into the reflection model itself. This article synthesizes the talks and discussions held at the 2025 Wake Forest workshop Recent Progress on Black Hole Spin Measurements Across the Electromagnetic and Gravitational Spectra; motivated by them, we propose a practical quality-control framework for assessing whether a published reflection-based spin measurement should be treated as robust, provisional, or not assessable from the published information alone. We organize the problem around three pillars: detectability, meaning that the relativistic reflection signal is unambiguously present in the data; uniqueness, meaning that the relativistic component can be separated from the continuum, from distant reflection, absorption, and instrumental effects; and robustness, meaning that the inferred spin is stable against plausible changes in model assumptions, data selection, and accretion-state treatment. We then translate these principles into applicable criteria, a tiered quality-classification scheme, and a reporting checklist for future analyses. The quantitative calibration of each criterion requires a dedicated campaign of simulations over realistic scenarios, which we outline here and defer to a future publication. We aim to define a reproducible path toward a curated, community-maintained compilation of reliable spin constraints and to guide the implementation of reflection spectroscopy in the high-throughput, high-resolution era. Full article

A new benzimidazole–6β-acetoxyvouacapane (4aS,5R,6aS,7R,11aS,11bR)-9-(1-benzyl-1H-benzo[d]imidazol-2-yl)-4,4,7,11b-tetramethyl-1,2,3,4,4a,5,6,6a,7,11,11a,11b-dodecahydrophenanthro[3,2-b]furan-5-yl acetate was synthesized through the semisynthetic functionalization of the natural product 6β-acetoxyvouacapane. The target compound was obtained via a liquid-assisted mechanochemical condensation of aldehyde 6β-acetoxyvouacapane with N-benzyl-o-phenylenediamine, followed by cyclization and oxidative aromatization under mild reaction conditions. The structure of the new compound was established by FT-IR, 1D and 2D NMR spectroscopy (COSY, HSQC, and HMBC), and high-resolution mass spectrometry (HRMS). Full article

A 9-methylacridinium salt, 10-(3,5-di-tert-butylphenyl)-9-methylacridin-10-ium tetrafluoroborate (2), was synthesized from the corresponding acridone by treatment with methylmagnesium bromide followed by tetrafluoroboric acid. Compound 2 was obtained as a yellow solid in 95% yield and characterized by NMR spectroscopy and high-resolution mass spectrometry. Electrochemical measurements revealed irreversible reduction behavior, with a reduction potential of −0.52 V vs. SCE determined by second-harmonic alternating-current voltammetry. Compound 2 exhibited absorption extending into the visible region and fluorescence at 492 nm with a lifetime of 4.6 ns. Unlike the previously reported 9-mesityl analogue, compound 2 was fluorescent, a difference that may reflect the absence of the high-lying donor orbital associated with the 9-mesityl group. Its singlet excited-state reduction potential was estimated to be +2.21 V vs. SCE, indicating substantial photooxidizing ability. DFT and TD-DFT calculations provided complementary insight into its frontier molecular orbital distributions and principal electronic transitions. These findings highlight the influence of the 9-substituent on the electronic and emissive properties of acridinium-based photoactive molecules. Full article

Background/Objectives: Plant secondary metabolites remain an invaluable source of novel antibacterial phytochemicals in the fight against antibiotic resistance. The medicinal plant Solidago gigantea Ait. (giant goldenrod) is an invasive species in Europe and represents an abundant, yet largely underexplored reservoir of such bioactive compounds. The primary aim of this study was to perform a non-targeted, effect-directed screening, detection, bioassay-guided isolation, structure elucidation, and microbiological assessment of the antibacterial constituents present in the inflorescences of S. gigantea. Methods: Thin-layer chromatography coupled with direct bioautography (TLC–DB) assay using Bacillus subtilis was utilized for the non-targeted, effect-directed analysis of antibacterial components and the evaluation of in vitro antibacterial activity. Successive preparative flash column chromatography, semi-preparative reversed-phase high-performance liquid chromatography (RP-HPLC), and thin-layer chromatography–mass spectrometry (TLC–MS) were employed for the bioassay-guided fractionation and isolation. The structures of the isolated compounds were elucidated using one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and high-resolution tandem mass spectrometry (HRMS/MS). The presence of known antibacterial compounds was established via reversed-phase ultra-high-performance liquid chromatography coupled with high-resolution electrospray ionization tandem mass spectrometry (RP-UHPLC–HR-ESI-MS/MS). Results: Two previously undescribed cis-clerodane diterpenoids, the isomeric solidagoic acid L (1) and solidagoic acid M (2), were isolated, identified, and characterized from the ethyl acetate extract of S. gigantea inflorescences. Both compounds exhibited in vitro antibacterial activity against the Gram-positive B. subtilis, confirmed via TLC–DB. In addition, 23 known compounds with antibacterial activity, including 17 clerodane diterpenes, four hydroxylated polyunsaturated fatty acids, and two unsaturated monoacylglycerols, were detected. All of these are reported for the first time in the inflorescences of this plant species. Conclusions: With further optimization, the isolated compounds may represent promising leads for antibacterial drug development. Our findings demonstrate the potential of non-targeted, bioassay-guided approaches for the discovery of novel plant-derived bioactive natural products. Full article

Nitric oxide (NO) is a small, highly reactive gaseous signaling molecule that plays diverse and context-dependent roles in microbial physiology and host–microbe interactions. Over the past decade, increasing evidence has revealed the dual nature of NO as both an antimicrobial effector and a signaling mediator involved in microbial stress responses, metabolism, biofilm dynamics, quorum sensing, virulence regulation, and symbiotic interactions. In microbial systems, NO influences adaptation to environmental stress and contributes to mechanisms associated with persistence and antimicrobial resistance. In host organisms, NO functions as a key component of innate immunity while also participating in beneficial interactions involving rhizobia, mycorrhizal fungi, and probiotic microorganisms. Despite its biological significance, accurate detection and quantification of NO remain challenging because of its transient nature, high reactivity, low physiological concentrations, and interference from related reactive oxygen and nitrogen species. Recent advances in biosensing technologies have substantially improved NO detection capabilities through the development of electrochemical, optical, enzyme-based, microfluidic, wearable, and implantable sensing platforms. These innovations are complemented by analytical techniques including electron paramagnetic resonance spectroscopy, mass spectrometry, fluorescence-based imaging, and advanced microscopy, which enhance sensitivity, specificity, and spatiotemporal resolution in complex biological environments. Concurrently, statistical and computational approaches—including sensor calibration models, multivariate analyses, machine learning algorithms, and bioinformatics pipelines—have become increasingly important for extracting biologically meaningful information from NO-related datasets. Unlike previous reviews that primarily focus on either NO biology or sensing technologies, this review integrates current knowledge of NO-mediated microbial physiology and host–microbe interactions with recent developments in biosensor engineering, analytical methodologies, statistical frameworks, and emerging artificial intelligence (AI)-driven data interpretation. We further highlight applications of NO detection in infectious disease diagnostics, antimicrobial screening, probiotic and biofertilizer evaluation, environmental microbiome monitoring, and real-time studies of symbiosis and infection. Finally, future directions including miniaturized sensing platforms, multi-omics integration, AI-assisted analytics, and sensor standardization are discussed. By unifying molecular, analytical, and computational perspectives, this review provides a multidisciplinary framework and roadmap for advancing NO-based research and translational applications across microbial, environmental, and host-associated systems. Full article

In this study, a compound with a novel chemical skeleton was isolated and purified from the fermentation broth of Streptomyces canarius SN0246. Its structure was elucidated using nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HRMS), and the compound was named canakingmycin. The in vitro antifungal activity of canakingmycin was evaluated against common crop pathogenic fungi, Rhizoctonia solani. The bioassay results showed that canakingmycin exhibited notable inhibitory effects on the mycelial growth of the phytopathogen, with the EC₅₀ value of 76.13 μg/mL. This study enriches the structural diversity of secondary metabolites from Streptomyces and provides a promising lead molecule and scientific basis for the development of new bio-based fungicides. Full article