Dimethyl Group Research Articles

LSD1 Conditional Myeloid Cell Knockout Mice have Decreased Osteoclast Differentiation Due to Increased IFN-β Gene Expression

Abstract Osteoclasts are large multinucleated cells that degrade bone mineral and extracellular matrix. Investigating the epigenetic mechanisms orchestrating osteoclast differentiation is key to our understanding of the pathogenesis of skeletal related diseases such as periodontitis and osteoporosis. Lysine specific demethylase 1 (LSD1/KDM1A) is a member of the histone demethylase family that mediates the removal of mono- and dimethyl groups from H3K4 and H3K9 to elicit dichotomous effects on gene expression. Prior to our study, little was known about the contributions of LSD1 to skeletal development and osteoclast differentiation. Here we show that conditional deletion of Lsd1 within the myeloid lineage or macrophage/osteoclast precursors results in enhanced bone mass of male and female mice accompanied by diminished osteoclast size in vivo. Furthermore, Lsd1 deletion decreased osteoclast differentiation and activity within in vitro assays. Our bulk RNA-SEQ data suggests Lsd1 ablation in male and female mice inhibits osteoclast differentiation due to enhanced expression of IFN-β target genes. Lastly, we demonstrate that LSD1 forms an immune complex with HDAC1 and HDAC2. These data suggest that the combination of methylation and acetylation of histone residues, facilitated by LSD1, mechanistically promotes osteoclast gene expression.

Efficient Energy Transfer from Quantum Dots to Closely‐Bound Dye Molecules without Spectral Overlap

Quantum dots (QDs) are semiconductor nanocrystals whose optical properties can be tuned by altering their size. By combining QDs with dyes we can make hybrid QD‐dye systems exhibiting energy transfer (ET) between QDs and dyes, which is important in sensing and lighting applications. In conventional QDs that need a shell to passivate surface defects, ET usually proceeds through Förster resonance energy transfer (FRET) that requires significant spectral overlap between QD emission and dye absorbance, as well as large oscillator strengths of those transitions. This considerably limits the choice of dyes. In contrast, perovskite QDs do not require passivating shells for bright emission, which makes ET mechanisms beyond FRET accessible. This work explores the design of a CsPbBr3 QD‐dye system to achieve efficient ET from CsPbBr3 QDs to dyes with dimethyl iminium binding groups where the close binding of dyes surface facilitates spatial wavefunction overlap. Using steady‐state and time‐resolved photoluminescence experiments, we demonstrate that efficient ET from CsPbBr3 to dyes with minimal spectral overlap proceeds via the Dexter exchange‐type mechanism, which overcomes the conventional restriction of spectral overlap that severely limits the tunability of these systems. This approach opens new avenues for QD‐molecule hybrids for a wide range of applications.

Efficient Energy Transfer from Quantum Dots to Closely-Bound Dye Molecules without Spectral Overlap.

Quantum dots (QDs) are semiconductor nanocrystals whose optical properties can be tuned by altering their size. By combining QDs with dyes we can make hybrid QD-dye systems exhibiting energy transfer (ET) between QDs and dyes, which is important in sensing and lighting applications. In conventional QDs that need a shell to passivate surface defects, ET usually proceeds through Förster resonance energy transfer (FRET) that requires significant spectral overlap between QD emission and dye absorbance, as well as large oscillator strengths of those transitions. This considerably limits the choice of dyes. In contrast, perovskite QDs do not require passivating shells for bright emission, which makes ET mechanisms beyond FRET accessible. This work explores the design of a CsPbBr3 QD-dye system to achieve efficient ET from CsPbBr3 QDs to dyes with dimethyl iminium binding groups where the close binding of dyes surface facilitates spatial wavefunction overlap. Using steady-state and time-resolved photoluminescence experiments, we demonstrate that efficient ET from CsPbBr3 to dyes with minimal spectral overlap proceeds via the Dexter exchange-type mechanism, which overcomes the conventional restriction of spectral overlap that severely limits the tunability of these systems. This approach opens new avenues for QD-molecule hybrids for a wide range of applications.

Design of experiments optimization of N,N,N-trimethyl chitosan synthesis using N,N-diisopropylethylamine base

This study presents a novel synthesis method of N,N,N-trimethyl chitosan (TMC) by using a non-nucleophilic base and optimizing the solvent system for enhanced scalability, while addressing critical factors such as viscosity management and stirring efficiency. The study objectives also included achieving high N,N,N-trimethylation without O-methylation while minimizing reagent use. Eight bases, three solvent systems, and varying levels of dilution were explored to mitigate viscosity challenges and gas evolution. 1H NMR spectroscopy was used to characterize the TMC products. The integral values of the peaks at 3.3, 3.0, and 2.8 ppm, corresponding to trimethyl, dimethyl, and monomethyl groups, were used to quantify the methylation degrees. The most promising initial results were obtained with N,N-diisopropylethylamine (DIPEA) base, and DMF as solvent. Using 6 eq methyl iodide (MeI) relative to chitosan and DIPEA as base, up to 68 % DTM was achieved. Applying Design of Experiments (DoE), the method was further optimized under diluted conditions, crucial for industrial scalability and viscosity control. Results from a full factorial design (32) revealed that diluted medium effectively prevented viscosity concerns, achieving a notably low viscosity of 5.9 cP in the reaction mixture, a 16-fold decrease in viscosity, compared to initial experiments. It was also established that both the MeI reagent and the base addition are significant factors for the DTM response, with both factors showing quadratic effects. The DoE model demonstrated high significance (R = 0.97), high precision for future prediction (Q2 = 0.87), good model validity (0.84) and excellent reproducibility (0.96). The results mark a notable advancement in TMC synthesis, offering an efficient and practical method with significant implications for industrial applications.

A polymeric structural approach to improving proton-blocking performance in anion exchange membranes for electrochemical systems

Anion exchange membranes are crucial in processes involving acids and bases, yet they often suffer from proton leakage, which diminishes system efficiency and membrane durability. To tackle this challenge, a novel polymeric structural approach was assessed to enhance proton-blocking performance. This approach scrutinized the interaction between protons and proton-attracting chemical species in the presence or absence of dimethyl (DM) groups within the poly(phenylene oxide) structure, and compared with the commercially available poly(aryl piperidinium) (PiperION) membrane containing strongly hydrophobic -CF3 groups. The findings revealed proton-blocking efficiencies of 60 % for PiperION, 62 % for PPO, and 72 % for DMPPO, with corresponding proton permeabilities of 36.71 × 10−6 cm2·s−1, 17.30 × 10−6 cm2·s−1, and 7.58 × 10−6 cm2·s−1, respectively. These results suggest enhanced proton-blocking performance with DM groups, while -CF3 groups do not provide a substantial improvement. Moreover, PPO-based membranes, when reinforced as composites, demonstrated superior proton-blocking capabilities compared to non-reinforced counterparts. These findings underscore the significance of designing anion exchange membranes with reduced proton interactions to achieve optimal proton-blocking performance in electrochemical systems.

Antimicrobial Hydrogels Based on Cationic Curdlan Derivatives for Biomedical Applications.

Hydrogels based on biocompatible polysaccharides with biological activity that can slowly release an active principle at the wound site represent promising alternatives to traditional wound dressing materials. In this respect, new hydrogels based on curdlan derivative with 2-hydroxypropyl dimethyl octyl ammonium groups (QCurd) and native curdlan (Curd) were obtained at room temperature by covalent cross-linking using a diepoxy cross-linking agent. The chemical structure of the QCurd/Curd hydrogels was investigated by Fourier transform infrared spectroscopy (FTIR) spectroscopy. Scanning electron microscopy (SEM) revealed well-defined regulated pores with an average diameter between 50 and 75 μm, and hydrophobic micro-domains of about 5 μm on the pore walls. The high swelling rate (21-24 gwater/ghydrogel) and low elastic modulus values (7-14 kPa) make them ideal for medical applications as wound dressings. To evaluate the possible use of the curdlan-based hydrogels as active dressings, the loading capacity and release kinetics of diclofenac, taken as a model drug, were studied under simulated physiological skin conditions. Several mathematical models have been applied to evaluate drug transport processes and to calculate the diffusion coefficients. The prepared QCurd/Curd hydrogels were found to have good antibacterial properties, showing a bacteriostatic effect after 48 h against S. aureus, MRSA, E. coli, and P. aeruginosa. The retarded drug delivery and antimicrobial properties of the new hydrogels support our hypothesis that they are candidates for the manufacture of wound dressings.

Comparison of Vinyldimethylaniline and Indolizine Donor Groups on Si‐Substituted Xanthene Core Shortwave Infrared Fluorophores

AbstractSmall organic molecules absorbing and emitting in the shortwave infrared (SWIR, 1000–2000 nm) region are desirable for biological imaging applications due to low auto‐fluorescence, reduce photon scattering, and good tissue penetration depth of photons which allows for in vivo imaging with high resolution and sensitivity. Si‐substituted xanthene‐based fluorophores with indolizine donors have demonstrated some of the longest wavelengths of absorption and emission from organic dyes. This work seeks to compare an indolizine heterocyclic nitrogen with dimethyl aniline nitrogen donors on otherwise identical Si‐substituted xanthene fluorophores via optical spectroscopy, computational chemistry and electrochemistry. Three donors are compared including an indolizine donor, a ubiquitous dimethyl aniline donor, and a vinyl dimethyl aniline group that keeps the number of π‐bonds consistent with indolizine. Significantly higher quantum yields and molar absorptivity are observed in these studies for a dimethylamine‐based donor relative to a simple indolizine donor absorbing and emitting at similar wavelengths (~1312 nm emission). Substantially longer wavelengths are obtainable by appending aniline‐based groups to the indolizine donor (~1700 nm) indicating longer wavelengths can be accessed with indolizine donors while stronger emitters can be accessed with anilines in place of indolizine.

Isosorbide-based Poly(arylene ether) biopolymer membranes for gas separation

Efforts to utilize biopolymer membranes to diminish the carbon footprint of separation processes are ongoing. Herein, we report the fabrication of isosorbide (ISB)-based poly(arylene ether) biopolymer membranes, including ISB-based poly(arylene ether sulfone) (I-PAES) and ISB-based poly(arylene ether ketone) (I-PAEK) for gas separation. The robust mechanical properties and amorphous nature of ISB-based biopolymers allow for their application to gas separations. Both positron annihilation lifetime spectroscopy (PALS) and free volume analysis using density measurements reveal that replacing bisphenol A (BPA) in polysulfone (PSF) with ISB results in a significant reduction in free volume owing to the absence of bulky dimethyl groups and the presence of polar aliphatic ether groups. Substituting the sulfone group for a ketone group further decreased free volume. Solid-state CP/MAS 13C NMR analysis discloses that substituting ISB and replacing sulfonyl moieties with carbonyl groups restricts the rotational motion of internal rings, resulting in inhibited gas diffusion. Consequently, the I-PAEK membrane exhibited H2/CO2 and H2/CH4 selectivities more than three times and five times higher, respectively, compared to the PSF counterpart. Our present study demonstrates the feasibility of ISB-based poly(arylene ether) biopolymer membranes for gas separation.

Discovery of Potent DAG-Lactone Derivatives as HIV Latency Reversing Agents.

Toward human immunodeficiency virus type-1 (HIV-1) cure, cells latently infected with HIV-1 must be eliminated from people living with HIV-1. We previously developed a protein kinase C (PKC) activator, diacylglycerol (DAG)-lactone derivative 3, with high HIV-1 latency-reversing activity, based on YSE028 (2) as a lead compound and found that the activity was correlated with binding affinity for PKC and stability against esterase-mediated hydrolysis. Here, we synthesized new DAG-lactone derivatives not only containing a tertiary ester group or an isoxazole surrogate but also several symmetric alkylidene moieties to improve HIV-1 latency reversing activity. Compound 9a, with a dimethyl group at the α-position of the ester group, exerted twice higher HIV-1 latency reversing activity than compound 3, and compound 26, with the isoxazole moiety, was significantly active. In addition, DAG-lactone derivatives with moderate hydrophobicity and potent biostability showed high biological activity.

Syntheses, characterizations, crystal structures and Hirshfeld surface analyses of methyl 4-[4-(di-fluorometh-oxy)phen-yl]-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate, isopropyl 4-[4-(di-fluoro-meth-oxy)phen-yl]-2,6,6-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate and tert-butyl 4-[4-(di-fluoro-meth-oxy)phen-yl]-2,6,6-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate.

The crystal structures and Hirshfeld surface analyses of three similar compounds are reported. Methyl 4-[4-(di-fluoro-meth-oxy)phen-yl]-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate, (C21H23F2NO4), (I), crystallizes in the monoclinic space group C2/c with Z = 8, while isopropyl 4-[4-(di-fluoro-meth-oxy)phen-yl]-2,6,6-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carb-oxyl-ate, (C23H27F2NO4), (II) and tert-butyl 4-[4-(di-fluoro-meth-oxy)phen-yl]-2,6,6-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate, (C24H29F2NO4), (III) crystallize in the ortho-rhom-bic space group Pbca with Z = 8. In the crystal structure of (I), mol-ecules are linked by N-H⋯O and C-H⋯O inter-actions, forming a tri-periodic network, while mol-ecules of (II) and (III) are linked by N-H⋯O, C-H⋯F and C-H⋯π inter-actions, forming layers parallel to (002). The cohesion of the mol-ecular packing is ensured by van der Waals forces between these layers. In (I), the atoms of the 4-di-fluoro-meth-oxy-phenyl group are disordered over two sets of sites in a 0.647 (3): 0.353 (3) ratio. In (III), the atoms of the dimethyl group attached to the cyclo-hexane ring, and the two carbon atoms of the cyclo-hexane ring are disordered over two sets of sites in a 0.646 (3):0.354 (3) ratio.

Exploring the staining potential of 1 GSK-3 inhibitors in bovine teeth: 2 a one-year laboratory investigation.

GSK-3 inhibitors, such as Tideglusib (TG) and CHIR-99021 (CHIR), show promise in stimulating reparative dentin formation. The aim of this study was to assess the discoloration potential of TG and CHIR in an established in vitro model. Enamel-dentin specimens made from bovine incisors were randomly allocated to five groups (n=15 each): group bovine blood (BB), group dimethyl sulfoxide (DMSO), group TG, group CHIR, and group mineral trioxide aggregate (MTA). Each specimen had a central cavity in which the respective material was applied and sealed with resin-based luting material. Color determination was conducted using a dental spectrophotometer at t0 (before filling), t1 (immediately after filling), t2 (after one week), t3 (after one month), t4 (after three months), t5 (after six months), and t6 (after one year). Statistical analysis involved descriptive statistics, Kruskal-Wallis tests, and analysis of variance (α=0.05). Group BB and group CHIR exhibited the most significant decrease in lightness (ΔL*) after one year (ΔL*-4.7 and ΔL* -5.7, respectively), whereas groups DMSO, TG, and MTA showed minimal changes (DMSO ΔL*: -0.3; TG ΔL*: 1.4; MTA ΔL*: -0.5). Group BB and CHIR exhibited the highest ΔE values (6.4Å}0.6 and 6.5Å}0.8, respectively). Unlike CHIR, TG did not result in discoloration exceeding the threshold of visual perception, defined by a ΔE value of 5.5, during the one-year observation period. This laboratory study therefore suggests that TG could be utilized for indirect or direct pulp capping without major discoloration concerns. However, additional research is required to corroborate these findings.

Dimethyl Sulfide Emissions From a Peatland Result More From Organic Matter Degradation Than Sulfate Reduction

AbstractVolatile sulfur compounds (VSCs) contribute to acid rain, cloud formation, and albedo, and thus influence the climate. Their global emissions are quite uncertain, especially contributions from freshwater wetlands. We investigated the processes leading to hydrogen sulfide (H2S), methanethiol (MeSH), and dimethyl sulfide (Me2S) emissions in a slightly acidic peatland and found multiple indications that organic matter degradation rather than sulfate reduction is the main driver for Me2S emissions in this system. Evidence includes: the lack of labeled Me234S production after addition of Na234SO4 despite high emissions of Me34SH and H234S, and increased emission rates when soils were amended with organic substrates containing thiol groups (H2S emissions), methylthiols (MeSH), and dimethyl sulfonio groups (Me2S). VSC precursors were identified from an Untargeted Metabolomics data set from the same soil. The abundance of sulfur cycling microbes like Acidobacteria SD 1 and Desulfosporosinus correlated with VSC emissions. We conclude that organic matter degradation is more important than sulfate reduction as a source of Me2S in our peatland system, and potentially also in other organic and wetland soils.

Antitubercular evaluation of dihydropyridine-triazole conjugates: design, synthesis, in vitro screening, SAR and in silico ADME predictions.

This study investigates the potential of click chemistry for the development of novel anti-tuberculosis agents. A targeted library of 1,4-dihydropyridine-1,2,3-triazole conjugates was synthesized and evaluated for their in vitro activity against Mycobacterium tuberculosis H37Ra using the resazurin microtiter assay (REMA). Among the synthesized derivatives, compounds J10, J11, J14, J22 and J23 demonstrated significant antimycobacterial activity. These compounds exhibited low MIC values ranging from 6.24 to 6.64 μg mL-1, highlighting their promising potential as lead compounds for further developing novel tuberculosis therapeutics. In addition to the promising in vitro activity, structure-activity relationship (SAR) analysis revealed that electron-withdrawing groups on the aryl-substituted ring of the dihydropyridines (J10-J24), a triazole with an unsubstituted aryl ring or with electron-donating groups (methyl or methoxy), and a geminal dimethyl group are essential structural features for the observed antitubercular activity. Furthermore, in silico ADME (absorption, distribution, metabolism, and excretion) parameters and pharmacokinetic studies supported the potential of these conjugates for oral bioavailability. These findings collectively highlight the 1,4-dihydropyridine-1,2,3-triazole scaffold as a promising platform for developing novel orally active anti-tuberculosis drugs.

Zirconium based metal-organic framework as highly efficient and acid-stable adsorbent for the rapid removal of Sr2+ and Cs+ from solution

Herein we present acid stable [Zr6(µ3-O)4(µ3-OH)4(OBA)4(OH)3(H2O)3(Me2NH2)]n (OBA = 4,4-oxy bis(benzoic acid)) (Zr(OBA) MOF) with the presence of cationic dimethyl ammonium groups were charge balanced with anionic Zr(OBA)nn– that is effective for removing Sr2+ and Cs+. This MOF shows distribution coefficients and record-high absorption capacities (Qm) of 353 mg/g for Sr2+ and 432.91 mg/g for Cs+ at pH 4, 112.75 mg/g for Sr2+ and 141.24 mg/g for Cs+ under 4 M HNO3 circumstances, and 221.5 mg/g for Sr2+ and 253.77 mg/g for Cs+ from simulated seawater. It was demonstrated that a significant excess of complex cations had no substantial influence on the removal of Sr2+ and Cs+ from simulated seawater and nuclear waste, which have been included with Sr2+ and Cs+. The Langmuir isotherm was well suited for Sr2+ and Cs+ adsorption onto MOF, confirming the existence of monolayer adsorption. This finding was made possible by investigating the Langmuir, Freundlich, and Temkin adsorption isotherms. The results of the experiments agree very well with pseudo-second-order kinetic studies, which leads one to believe that chemisorption is the primary mechanism. The measurement of zeta potential has indicated an electrostatic connection between the negatively charged surface of the MOF and positively charged Sr2+/Cs+ at various pH values. This interaction demonstrates that the adsorption capacity is relatively high. SEM-EDS elemental mapping, IR, and XPS analysis confirm the presence of Sr2+ and Cs+ on MOF - of Zr(OBA)@Sr and Zr(OBA)@Cs MOF after adsorption studies. Sr2+/Cs+ exchanged MOF were improved in order to get a clear image of the ion exchange process, and the binding energies of −87.31 for Zr(OBA)@Sr and −113.75 kJ/mol for Zr(OBA)@Cs, respectively. The dose, initial concentration of metal ions, pH solution, contact time, and other ions of Na+, K+, Ca2+, and Mg2+ that were already present affected the adsorption of Sr2+ and Cs+. Recycle studies of Zr(OBA) MOF show 80 % recovery of Sr2+ and Cs+ even after eight cycles.

Biosynthesis, characterization, and biodegradation of elastomeric polyhydroxyalkanoates consisting of α-dimethylated monomer units

Although poly[(R)-3-hydroxybutyrate)] [P(3HB)] is a microbial polyester that can be used as a sustainable and biodegradable plastic, its use has been limited because of poor material properties due to its stiff and brittle nature. To overcome this issue, it is critical to diversify the monomeric composition of 3HB-based polymers through the introduction of new repeating units that can improve material properties. In this study, a new 3HB-based copolymer was biosynthesized with 3-hydroxypivalate (3HPi) units containing signature dimethyl groups on the α-carbon. To biosynthesize poly[(R)-3-hydroxybutyrate-co-3-hydroxypivalate] {P(3HB-co-3HPi)}, recombinant Escherichia coli LSBJ was cultured with glucose and 3-hydroxypivalic acid (3HPiA) as the carbon source and 3HPi precursor, respectively. This resulted in the successful synthesis of P(3HB-co-3HPi) copolymers with a 3HPi fraction in the range of 2–50 mol% by adjusting the precursor concentration to the microbial catalyst. Interestingly, the biosynthesized polymers exhibited an increasing molecular weight with increasing 3HPi fractions, up to 424 × 104 in weight average molecular weight. The thermal properties of P(3HB-co-3HPi) were similar to those of conventional 3HB-based copolymers, but the copolymers displayed extraordinary mechanical performance compared to other 3HB homo- and copolymers. P(3HB-co-32 mol% 3HPi) displayed an elongation at break of 1919 %, the highest value ever reported for bacterial polyesters. Given its high flexibility, P(3HB-co-3HPi) copolymers exhibited reversible deformation during tension testing, unlike other 3HB-based copolymers. Furthermore, P(3HB-co-3HPi) copolymers and monomeric 3HPiA were both biodegradable. This study has demonstrated that the incorporation of 3HPi monomers into 3HB-based copolymers results in superior mechanical properties and has introduced a promising new class of materials for use as sustainable and biodegradable plastics.

Synthetic approach to spiropyranocoumarins and their oxime derivatives

This study explores the synthesis of a diverse series of linear (spiro)pyranocoumarins and their corresponding oximes, compounds known for their promising biological activities. Building on previous work, the authors expand the array of target compounds, adding structural features such as dimethyl groups and various cycloaliphatic rings. The novel synthetic procedure applied herein couples o-hydroxyacetyl coumarins with respective ketones via Kabbe condensation, yielding 16 derivatives, including 12 new compounds. A further step engages these (spiro)pyranocoumarins with hydroxylamine hydrochloride, leading to oximes, selectively at the exocyclic oxygen atom of the chroman-4-one fragment. Optimizing synthesis conditions has increased product yields and reduced reaction times. Acidic hydrolysis of select compounds introduces additional carbonyl groups and facilitates deprotection, while the subsequent reaction with hydroxylamine hydrochloride produces dual-oxime compounds. These findings contribute to the ongoing development of pyranocoumarin and oxime-based therapeutics, with potential applications in treating various diseases

The Disorazole Z Family of Highly Potent Anticancer Natural Products from Sorangium cellulosum: Structure, Bioactivity, Biosynthesis, and Heterologous Expression.

Myxobacteria serve as a treasure trove of secondary metabolites. During our ongoing search for bioactive natural products, a novel subclass of disorazoles termed disorazole Z was discovered. Ten disorazole Z family members were purified from a large-scale fermentation of the myxobacterium Sorangium cellulosum So ce1875 and characterized by electrospray ionization-high-resolution mass spectrometry (ESI-HRMS), X-ray, nuclear magnetic resonance (NMR), and Mosher ester analysis. Disorazole Z compounds are characterized by the lack of one polyketide extension cycle, resulting in a shortened monomer in comparison to disorazole A, which finally forms a dimer in the bis-lactone core structure. In addition, an unprecedented modification of a geminal dimethyl group takes place to form a carboxylic acid methyl ester. The main component disorazole Z1 shows comparable activity in effectively killing cancer cells to disorazole A1 via binding to tubulin, which we show induces microtubule depolymerization, endoplasmic reticulum delocalization, and eventually apoptosis. The disorazole Z biosynthetic gene cluster (BGC) was identified and characterized from the alternative producer S. cellulosum So ce427 and compared to the known disorazole A BGC, followed by heterologous expression in the host Myxococcus xanthus DK1622. Pathway engineering by promoter substitution and gene deletion paves the way for detailed biosynthesis studies and efficient heterologous production of disorazole Z congeners. IMPORTANCE Microbial secondary metabolites are a prolific reservoir for the discovery of bioactive compounds, which prove to be privileged scaffolds for the development of new drugs such as antibacterial and small-molecule anticancer drugs. Consequently, the continuous discovery of novel bioactive natural products is of great importance for pharmaceutical research. Myxobacteria, especially Sorangium spp., which are known for their large genomes with yet-underexploited biosynthetic potential, are proficient producers of such secondary metabolites. From the fermentation broth of Sorangium cellulosum strain So ce1875, we isolated and characterized a family of natural products named disorazole Z, which showed potent anticancer activity. Further, we report on the biosynthesis and heterologous production of disorazole Z. These results can be stepping stones toward pharmaceutical development of the disorazole family of anticancer natural products for (pre)clinical studies.

Exploiting common ion addition to accelerate zolpidem hemitartrate release from Eudragit EPO extrudates

The current study aimed at optimizing a previously developed non-clinical formulation for use in zolpidem deprescribing. The formulation under investigation consists of extruded zolpidem hemitartrate (30% w/w) and Eudragit EPO (70% w/w) mixtures which display unsatisfactory dissolution behavior. Both milled extrudates and physical mixtures were compressed to produce tablets with identical target weight and solid fraction. First, the susceptibility of zolpidem hemitartrate towards heat and shear degradation was identified utilizing thermal and HPLC-DAD analysis. The drug salt proved prone to thermally induced disproportionation. Moreover, the impurity content increased after applying hot melt extrusion although ICH guidelines were still attained. Secondly, extrudates and physical mixtures were subjected to FTIR analysis. As a result, interaction and protonation of the dimethyl aminoethyl group from Eudragit EPO resulting from zolpidem disproportionation was elucidated. As such, the formulations’ slow dissolution kinetics in comparison to formulations containing non-ionizable polymers (e.g. Kollidon 12PF and Kollidon VA64) is explained. Finally, addition of tartaric acid, a microenvironmental pH modulator and common ion, proved a successful method to increase dissolution kinetics. The amount of drug released after 15 min increased drastically from 10 to 40% upon the addition of 5% tartaric acid. Immediate release behavior (80% within 15 min) was however not yet attained.

Nifuroxazide induces the apoptosis of human non‑small cell lung cancer cells through the endoplasmic reticulum stress PERK signaling pathway.

The aim of the present study was to investigate the molecular mechanism of nifuroxazide (NFZ) in the induction of apoptosis of NCI-H1299 human non-small cell lung cancer (NSCLC) cells through the reactive oxygen species (ROS)/Ca2+/protein kinase R-like ER kinase (PERK)-activating transcription factor 4 (ATF4)-DNA damage inducible transcript 3 (CHOP) signaling pathway. Morphological changes of cells were observed by microscopy, and the apoptosis and intracellular ROS levels of cells were observed by inverted fluorescence microscopy. Cell viability after the addition of the PERK inhibitor, GSK2606414, were detected by Cell Counting Kit-8 assay. Annexin V-FITC was used to detect cell apoptosis, Brite 670 was used to detect intracellular ROS and Fura Red AM was used to detect Ca2+ content. Western blotting was used to detect PERK, phosphorylated (P)-PERK, ATF4, CHOP, P-Janus kinase 2 and P-signal transducer and activator of transcription 3 expression levels. Compared with the dimethyl sulfoxide control group, NFZ inhibited the survival activity in the H1299 NSCLC cell line, in a time- and dose-dependent manner. However, GSK2606414 inhibited the NFZ-induced apoptosis of H1299 cells. GSK2606414 also inhibited the increase in ROS and Ca2+ in H1299 cells induced by NFZ. Western blotting results demonstrated that NFZ significantly increased the expression levels of P-PERK, ATF4 and CHOP, whereas GSK2606414 significantly reduced the NFZ-induced increase in these protein expression levels. In conclusion, NFZ may induce the apoptosis of H1299 NSCLC cells through the ROS/Ca2+/PERK-ATF4-CHOP signaling pathway.

Infrared spectroscopy of isolated molecules having a dimethyl group in CCl4

The in-situ inclusion of acetone, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), and 2-propanol into carbon tetrachloride (CCl4) were investigated by infrared vibrational spectroscopy. IR spectra in the CH stretch region were very different although the dimethyl group responsible for this region of the spectra is common for all these molecules. The difference between the spectra was explained in terms of the DFT calculations of the monomer molecules. The spectra changed appreciably in the in-situ inclusion process for acetone and 2-propanol, while did not change for DMSO and DMF, aside from an increase proportional to increased concentration. The structures of the molecules in the time series were verified by quantum chemical calculations of monomers and dimers for these molecules, and their vibrational spectra were also calculated. The results indicate that DMSO and DMF having large molecular dipole moments are included as a dimer (or multimer) into the CCl4 matrix due to the strong dipole interaction, while the other molecules first enter the CCl4 phase as monomers and take multimer structures afterwards.