Explore the vast range of titles available.

Vicinal diamines are a common structural motif in bioactive natural products, therapeutic agents, and molecular catalysts, motivating the continuing development of efficient, selective, and sustainable technologies for their preparation. We report an operationally simple and environmentally friendly protocol that converts alkenes and sodium azide—both readily available feedstocks—to 1,2-diazides. Powered by electricity and catalyzed by Earth-abundant manganese, this transformation proceeds under mild conditions and exhibits exceptional substrate generality and functional group compatibility. Using standard protocols, the resultant 1,2-diazides can be smoothly reduced to vicinal diamines in a single step, with high chemoselectivity. Mechanistic studies are consistent with metal-mediated azidyl radical transfer as the predominant pathway, enabling dual carbon-nitrogen bond formation.

Multidrug-resistant (MDR) pathogens represent a major global health challenge, underscoring the urgent need for new antimicrobial strategies that can effectively target both planktonic cells and biofilm-associated infections. This study integrated in vitro antimicrobial and antibiofilm assays with comprehensive in silico analyses to evaluate the repurposing potential of thymol (TM), sodium azide (SA), and sodium lauryl sulfate (SLS) against 17 bacterial and two fungal strains, including methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates. TM showed the strongest overall antimicrobial activity, with low MIC/MBC values (0.10–0.20 mg/mL) and potent antibiofilm effects (MBIC: 0.20–0.39 mg/mL; MBEC: 0.39–0.78 mg/mL). In contrast, SA exhibited similar MICs (0.10–0.78 mg/mL) but required much higher concentrations for bactericidal and antibiofilm endpoints (MBC/MBIC/MBEC 6.25–100 mg/mL), whereas SLS displayed variable activity, with low MICs against most Gram-positive bacteria (0.10–0.20 mg/mL) but high MBC/MBIC/MBEC values (50–100 mg/mL), especially for Gram-negative biofilms. Molecular docking and 300 ns molecular dynamics (MD) simulations revealed that TM forms stable complexes with key microbial targets, most notably FtsZ ( ΔG = –11.0 kcal/mol; K d = 3.2 × 10 ⁻ ¹⁰ M), supported by favorable MM/GBSA binding energies and restrained motions in principal component analysis/free-energy landscape (PCA/FEL) analyses. SA and SLS were primarily used as mechanistic comparators (respiratory inhibitors and membrane disruptors, respectively). In contrast, their non-ionic analogs, phenyl azide (PA) and lauryl sulfate (LS), were explored as potential scaffolds. LS showed a very high predicted affinity for UDP-3-O-acyl- N -acetylglucosamine deacetylase (LpxC) ( ΔG = –19.9 kcal/mol; K d = 1.7 × 10 ⁻ ¹¹ M), indicating promise for future optimization. In silico ADMET profiling identified TM as the most balanced candidate, combining broad-spectrum antibiofilm efficacy with a comparatively favorable predicted safety profile. Overall, TM emerges as a viable repurposable antimicrobial agent, whereas LS-based derivatives represent computationally prioritized scaffolds that warrant further experimental validation.

The nature and effect of mutations are of fundamental importance to the evolutionary process. The generation of mutations with mutagens has also played important roles in genetics. Applications of mutagens include dissecting the genetic basis of trait variation, inducing desirable traits in crops, and understanding the nature of genetic load. Previous studies of sodium azide-induced mutations have reported single nucleotide variants (SNVs) found in individual genes. To characterize the nature of mutations induced by sodium azide, we analyze whole-genome sequencing (WGS) of 11 barley lines derived from sodium azide mutagenesis, where all lines were selected for diminution of plant fitness owing to induced mutations. We contrast observed mutagen-induced variants with those found in standing variation in WGS of 13 barley landraces. Here, we report indels that are two orders of magnitude more abundant than expected based on nominal mutation rates. We found induced SNVs are very specific, with C → T changes occurring in a context followed by another C on the same strand (or the reverse complement). The codons most affected by the mutagen include the sodium azide-specific CC motif (or the reverse complement), resulting in a handful of amino acid changes and few stop codons. The specific nature of induced mutations suggests that mutagens could be chosen based on experimental goals. Sodium azide would not be ideal for gene knockouts but will create many missense mutations with more subtle effects on protein function.

In recent years there has been a surge in the development of methods for the synthesis of organofluorine compounds. However, enzymatic methods for C-F bond formation have been limited to nucleophilic fluoride substitution. Here, we report the incorporation of iron-catalysed radical fluorine transfer, a reaction mechanism that is not used in naturally occurring enzymes, into enzymatic catalysis for the development of biocatalytic enantioselective C( )-F bond formation. Using this strategy, we repurposed ( )-2-hydroxypropylphosphonate epoxidase from ( HppE) to catalyse an -fluoroamide directed C( )-H fluorination. Directed evolution has enabled HppE to be optimized, forming diverse chiral benzylic fluoride products with turnover numbers of up to 180 and with excellent enantiocontrol (up to 94% e.e.). Mechanistic investigations showed that the N-F bond activation is the rate-determining step, and the strong preference for fluorination in the presence of excess NaN can be attributed to the spatial proximity of the carbon-centered radical to the iron-bound fluoride.

Conjugation is a type of horizontal gene transfer (HGT) that serves as the primary mechanism responsible for accelerating the spread of antibiotic resistance genes in Gram-negative bacteria. The present study aimed to elucidate the mechanisms underlying the conjugation-mediated gene transfer from the extensively drug-resistant Acinetobacter baumannii (XDR-AB) and New Delhi Metallo-beta-lactamase-1-producing Acinetobacter baumannii (NDM-AB) to environmental isolates of Acinetobacter spp. Conjugation experiments demonstrated that resistance to ticarcillin and kanamycin could be transferred from four donors to two sodium azide-resistant A. baumannii strains, namely, NU013R and NU015R. No transconjugants were detected on Mueller-Hinton Agar (MHA) plates containing tetracycline. Plasmids obtained from donors as well as successful transconjugants were characterized by PCR-based replicon typing and S1-nuclease pulsed-field gel electrophoresis (S1-PFGE). Detection of antibiotic resistance genes and integrase genes (int) was performed using PCR. Results revealed that the donor AB364 strain can transfer the blaOXA-23 and blaPER-1 genes to both recipients in association with int1. A 240-kb plasmid was successfully transferred from the donor AB364 to recipients. In addition, the aphA6 and blaPER-1 genes were co-transferred with the int1 gene from the donor strains AB352 and AB405. The transfer of a 220-kb plasmid from the donors to recipient was detected. The GR6 plasmid containing the kanamycin resistance gene (aphA6) was successfully transferred from the donor strain AB140 to both recipient strains. However, the blaNDM-1 and tet(B) genes were not detected in all transconjugants. Our study is the first to demonstrate successful in vitro conjugation, which indicated that XDR-AB contained combination mechanisms of the co-transfer of antimicrobial resistance elements with integron cassettes or with the plasmid group GR6. Thus, conjugation could be responsible for the emergence of new types of antibiotic-resistant strains.

Chromosomal loci jiggle in place between segregation events in prokaryotic cells and during interphase in eukaryotic nuclei. This motion seems random and is often attributed to Brownian motion. However, we show here that locus dynamics in live bacteria and yeast are sensitive to metabolic activity. When ATP synthesis is inhibited, the apparent diffusion coefficient decreases, whereas the subdiffusive scaling exponent remains constant. Furthermore, the magnitude of locus motion increases more steeply with temperature in untreated cells than in ATP-depleted cells. This \"superthermal\" response suggests that untreated cells have an additional source of molecular agitation, beyond thermal motion, that increases sharply with temperature. Such ATP-dependent fluctuations are likely mechanical, because the heat dissipated from metabolic processes is insufficient to account for the difference in locus motion between untreated and ATP-depleted cells. Our data indicate that ATP-dependent enzymatic activity, in addition to thermal fluctuations, contributes to the molecular agitation driving random (sub)diffusive motion in the living cell.

Aqueous microdroplets have fascinated scientists with unique properties that deviate from bulk solutions. Understanding microdroplet chemistry has been limited by few spectroscopic measurements on single well-defined microdroplets. Here we present a new technique to record an IR spectrum of a single droplet called Single Droplet Displacement Infrared Action Spectroscopy (SiDDIRAS) with potential broad applications in physical, analytical, and environmental chemistry. The droplet was trapped in a linear quadrupole electrodynamic balance. When IR radiation at resonant frequency was introduced, mass loss from IR-induced evaporation caused the droplet to displace upwards. Mapping the displacement as a function of IR frequency yields an IR spectrum of a single microdroplet. As a demonstration, the SiDDIRA spectrum of an ~8 µm droplet containing NaCl and NaN 3 shows that the azide asymmetric stretch blueshifts by 5 cm -1 relative to bulk with significant peak broadening, evidence that this droplet is supersaturated with salts compared to bulk solutions. Single Droplet Displacement IR Action Spectroscopy is a new technique to obtain IR spectra of substrate-free single droplets held in an electrodynamic balance by mapping the droplet’s IR-induced displacement as a function of IR frequency.

The long-sought cubic gauche phase of polymeric nitrogen (cg-PN) with nitrogen-nitrogen single bonds has been synthesized together with a related phase by a radio-frequency plasma reaction under near-ambient conditions. Here, we report the synthesis of polymeric nitrogen using a mixture of nitrogen and argon flowing over bulk β-sodium azide or β-sodium azide dispersed on 100 nm long multiwall carbon nanotubes. The cg-PN phase is identified by Raman and attenuated total reflection-Fourier transform infrared spectroscopy, and powder X-ray diffraction. The synthesis of the cubic gauche allotrope of high energy density polymeric nitrogen under near-ambient conditions should therefore enable its optimized production and applications as a “green” energetic material and a potential catalyst for different chemical reactions. Polymeric phases of nitrogen are promising as environmentally-friendly, high energy-density materials, but are inherently unstable. Here, the authors report the synthesis and stabilization of polymeric nitrogen in its cubic gauche phase under near-ambient conditions, via plasma-enhanced chemical vapour deposition.

Trigonella , commonly known as Fenugreek, is among the most promising medicinal herbs consumed worldwide due its protein rich dietary contributions. This study involved induced mutagenesis on two Trigonella species ( Trigonella foenum-graecum var. PEB and Trigonella corniculata var. Pusa kasuri) using caffeine and sodium azide as mutagens, resulting in the identification of nine high-yielding mutant lines in the M 3 generation. Molecular characterization using SCoT markers revealed a high polymorphism of 28.3% and 46.7% in PEB and Pusa kasuri, respectively, facilitating the investigation of genetic divergence among the control and mutant lines. Similarity correlation analysis indicated a high similarity between mutant A and mutant C (0.97) and between mutant J and mutant O (0.88), while the lowest similarity was observed between mutant B and mutant F (0.74) and between control and mutant L (0.58). Mutant F and Mutant J displayed the highest seed yield and its attributing traits, and seed protein content in PEB and Pusa kasuri, respectively. Physiological parameters, including chlorophyll content (Mutants A and N) and carotenoids (mutant A and J), exhibited improvements. Assessment of stomatal and seed characteristics using scanning electron microscopy may lead to improved physiological processes and distinction at the interspecific level, respectively. Methanolic extracts of the control and the mutant lines of both species were subjected to GC-MS analysis, revealing 24 major phytocompounds known for their pharmacological activities (antioxidant, anti-inflammatory, anticancer, etc.). Statistical methods such as Pearson correlation heatmap and pairwise scatter plot matrix provided insights into the correlations and linear associations among parameters for both PEB and Pusa kasuri. The strong correlation between iron content and seeds per pod in the mutant lines suggests a promising avenue for further research. Continued research and breeding efforts using these mutants can lead to significant advancements in agriculture and medicine, benefiting farmers, consumers, and industries alike.

A novel extracellular thermo-alkali-stable laccase from Bacillus tequilensis SN4 (SN4LAC) was purified to homogeneity. The laccase was a monomeric protein of molecular weight 32 KDa. UV-visible spectrum and peptide mass fingerprinting results showed that SN4LAC is a multicopper oxidase. Laccase was active in broad range of phenolic and non-phenolic substrates. Catalytic efficiency (kcat/Km) showed that 2, 6-dimethoxyphenol was most efficiently oxidized by the enzyme. The enzyme was inhibited by conventional inhibitors of laccase like sodium azide, cysteine, dithiothreitol and β-mercaptoethanol. SN4LAC was found to be highly thermostable, having temperature optimum at 85°C and could retain more than 80% activity at 70°C for 24 h. The optimum pH of activity for 2, 6-dimethoxyphenol, 2, 2'-azino bis[3-ethylbenzthiazoline-6-sulfonate], syringaldazine and guaiacol was 8.0, 5.5, 6.5 and 8.0 respectively. Enzyme was alkali-stable as it retained more than 75% activity at pH 9.0 for 24 h. Activity of the enzyme was significantly enhanced by Cu2+, Co2+, SDS and CTAB, while it was stable in the presence of halides, most of the other metal ions and surfactants. The extracellular nature and stability of SN4LAC in extreme conditions such as high temperature, pH, heavy metals, halides and detergents makes it a highly suitable candidate for biotechnological and industrial applications.