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The aim of the work was to synthesize novel heterocyclic compounds derived from camphor with antibacterial activity. The pyridazine, xanthene, pyranothiazole, pyridinothiazole, thiophene and pyrazole derivatives were produced from 4,11,11-trimethyl-9-phenyl-7-(2-phenylhydrazono)-3,4,5,6,7,9-hexahydro-1H-1,4- methanoxanthen-8(2H)-one (1). Thiophene derivatives 6a,b were produced according to the Gewald’s reaction for thiophene synthesis. On the other hand, pyranothiazol derivatives 8a,b were synthesized by the multicomponent reactions between xanthene derivative 5, benzaldehyde and ethylcyanoacetate or malononitrile in ethanol/triethylamine. Whereas, pyridinothiazole derivative 9 was produced in ethanol/ammonium acetate by the multicomponent reaction between xanthene derivative 5, benzaldehyde and malononitrile. The antibacterial activity of the synthesized compounds was evaluated against E. coli bacteria. All synthesized compounds showed moderate activity against E. coli bacteria. [ABSTRACT FROM AUTHOR]

A new method has been proposed for the green and efficient synthesis of xanthenediones and their corresponding open-chain analogs aryl-methylene bis(3-hydroxy-5,5'-dimethyl-2-cyclohexene-1-ones) using natural acid, Lemon juice, as the catalyst. This method involves the use of lemon juice as a surfactant-type bronsted acid, which makes it non-polluting and produces a high-purity product with excellent yield. Additionally, the work-up procedure is clean and straightforward. Dimedone and aldehydes are the starting materials for this process. [ABSTRACT FROM AUTHOR]

Photoacoustic (PA) imaging is a powerful biomedical imaging modality. We designed KeTMR and KeJuR, two xanthene-based dyes that were readily obtained through a 2-step synthetic route. KeJuR has low molecular weight, good aqueous solubility, and superior chemical stability compared to KeTMR. KeJuR shows a robust PA signal under 860 nm excitation and can be paired with traditional PA dyes for multiplex imaging in blood samples under a tissue-mimicking environment.

Porous organic polymers (POPs) – the emergent hydrothermally stable, amorphous and porous materials – have proven to be invaluable for catalytic applications. Through a rational bottom‐up design, we have developed a Carboxy‐POP, a POP that is adorned by Bronsted acid (COOH) functionalities, for heterogeneous catalysis. The Carboxy‐POP has been comprehensively characterized by FT‐IR, solid‐state 13C NMR, SEM, TEM, etc. It exhibits a moderate porosity with a BET surface area of 381 m2 g−1 and acid concentration of 1.67 mmol/g. Its functional utility as an efficient heterogeneous catalyst for one‐pot synthesis of a variety of xanthenes and acridines in excellent isolated yields (up to 98 %) is demonstrated. In contrast to the conventional methods, the advantages of the reported metal‐free catalytic protocol include ease of operation, excellent isolated yields of the products, facile workup, and shorter reaction times. It is shown that the heterogeneous catalyst can be repetitively used with the catalytic activity almost intact even after 16 reaction cycles. [ABSTRACT FROM AUTHOR]

This paper describes the direct synthesis of carboxamide-functionalized nano NaY zeolite (CBA-Ze) to develop a new high-functionality nanocatalyst in one pot process. This surface functionalization was achieved using a four-component Ugi reaction. Afterward, copper ions were coordinated with Ugi-ligands decorated on the nano NaY zeolite surface. To characterize the synthesized catalysts, fourier transform-infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential thermal analysis, scanning electron micrograph, transmission electron microscopy, X‐ray diffraction (XRD), dynamic light scattering, energy dispersive spectroscopy, inductively coupled plasma, and elemental analyses were used. The nature of the supported Ugi-ligand on the zeolite's surface improved the catalyst reactivity of the zeolite, made it more homogeneous, and increased its ability to coordinate with copper ions. The catalytic activity of the synthesized copper-carboxamide complex immobilized on nano NaY zeolite (Cu@CBA-Ze) was investigated in the synthesis of Xanthen derivatives, resulting in product yields of 85–98% Cu@CBA-Ze using only 20 mg in H2O:EtOH (1:1) at room temperature within 30 min. In addition to the ease of recovering and reusing catalyst, and the simple setup procedure, this method is an eco-friendly, benign procedure for synthesizing heterocycles. This study describes a catalytic system with the potential to produce other useful heterocyclic compounds under mild environmental conditions. [ABSTRACT FROM AUTHOR]

Xanthene, chromene, thiazole, thiophene, pyrazole, and isoxazole derivatives were synthesized from camphor-D monoterpene using multi-component reactions. Camphor has anti-bacterial, anti-fungal and antiinflammatory properties. It is also used to mitigate pain, treat skin diseases, and improve respiratory functions. In this research, we focus on the effectiveness of the produced compounds from the biologically active camphor. The produced compounds were formed according to various reactions such as a Knoevenagel condensation, Michael adduct, Gewald reaction, a nucleophilic attack, substitution, addition, elimination and cyclization reactions. Furthermore, the novel produced compounds have been tested towards the six cancer cell lines namely A549, MKN-45, U87MG, HT-29, H460 and SMMC-772. Compounds 5, 11, 15b, 16, 25b and 27b displayed the highest inhibitions compounds toward the mentioned cancer cell lines. In addition, compounds 3, 13, 15a, 22a, 27a and 28 showed moderate inhibitory effects against the cancer cell lines. [ABSTRACT FROM AUTHOR]

D-2-hydroxyglutarate (D2HG) is over-produced as an oncometabolite due to mutations in isocitrate dehydrogenases (IDHs). Accumulation of D2HG can cause the dysfunction of many enzymes and genome-wide epigenetic alterations, which can promote oncogenesis. Quantification of D2HG at single-cell resolution can help understand the phenotypic signatures of IDH-mutant cancers and identify effective therapeutics. In this study, we developed an analytical method to detect D2HG levels in single cancer cells by adapting cascade enzymatic reactions on a resazurin-based fluorescence reporter. The resazurin probe was immobilized to the sensing surface via biotin-streptavidin interaction. This surface chemistry was rationally optimized to translate the D2HG levels to sensitive fluorescence readouts efficiently. This D2HG assay demonstrated good selectivity and high sensitivity toward D2HG, and it was compatible with the previously developed single-cell barcode chip (SCBC) technology. Using the SCBC platform, we performed simultaneous single-cell profiling of D2HG, glucose uptake, and critical oncogenic signaling proteins in single IDH-mutant glioma cells. The results unveiled the complex interplays between metabolic and oncogenic signaling and led to the identification of effective combination targeted therapy against these IDH-mutant glioma cells.

A series of rhodol‐; fluorescein‐ and rhodamines‐based spirolactam compounds, bearing electron donor amines have been prepared. For this purpose we have redesigned the synthesis of the rhodol scaffold using 2‐(2,4‐dihydroxybenzoyl)benzoic acid obtaining one example rhodol methyl ester in good yields (25–30 %) Thus, one set of non‐cytotoxic rhodamine‐based compounds has been prepared using thermal and microwave assisted synthesis (40–78 %) and tested as high affinity ATP chemo‐sensors. [ABSTRACT FROM AUTHOR]

β-Enaminones derived from cyclohexane-1,3-diones reveal a vast variety of bioactivities including anticonvulsant, anti-inflammatory, analgesic, etc. Further, these β-Enaminones are versatile precursors for the synthesis of several other important heterocycles that illustrates antimicrobial, antibacterial, antifungal, antitumor, calcium channel antagonist, cardiovascular, antiviral activities, etc. Recently, reactions of various β-enaminones with their counterpart for example aldehydes, Meldrum's acid, N-arylitaconimides, malononitriles, cyanoacetamide, arylglyoxals, ortho-hydroxybenzyl alcohols, o-hydroxystyrenes, and acenaphthoquinone have been recognized for the synthesis of different nitrogen and oxygen heterocycles involving 2-quinolone, 1,4-dihydropyridine, acridine-1,8-dione, indoles, xanthenes, chromenones, etc. These significances of β-enaminones enthused us to assemble all newly developed methods for the creation of important nitrogen and oxygen-containing heterocycles, which are the chief attraction of this review article. [ABSTRACT FROM AUTHOR]

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In this study, glycine-based ionic liquid ([Gly-H][OTs]) was synthesized through a reaction of glycine with ρ-toluenesulfonic acid in water. The synthesized IL was utilized for the one-pot, multi-component synthesis of 3,4-dihydropyrimidin-2(1H)-ones, 14-aryl-14H-dibenzo[a,j]xanthenes and 12-aryl-8,9,10,12-tetrahydrobenzo [a]xanthene-11-ones under solvent-free condition. The prepared IL indicates desirable catalytic activity in organic reactions under solvent-free conditions with the high reusability of four runs. The proposed protocol's main advantages are the originality of prepared [Gly-H][OTs], organic green synthesis under solvent-free conditions, high product yields, and less reaction times. [ABSTRACT FROM AUTHOR]

Recently, the combined application of synergistic therapies for photodynamic antimicrobial chemotherapy has become important to obtain more efficient results. The synergism between two sensitizers, rose bengal (RB) and chlorin e6 (Ce6), excited by two different methods, was evaluated as a novel approach to both photodynamic and sonodynamic therapy against methicillin-resistant Staphylococcus aureus. The sonostability and singlet oxygen generation (with 1,3-diphenylisobenzofuran for RB and tetrathiafulvalene for Ce6) were measured under sonication (1 MHz, 3 W) using a spectrophotometer. RB and Ce6 remained stable during sonication. RB was a more efficient sonosensitizer than Ce6. The dual synergism between RB and Ce6 was noticed, achieving a >3 log reduction for molar ratios RB:Ce6 of 1:1 and 1:3, while, alone, the sensitizers excited with ultrasound and light, respectively, achieved only ca. a 1 log reduction. [ABSTRACT FROM AUTHOR]

Arylmethylenebis(3-hydroxy-2-cyclohexen-1-ones) were obtained by condensation of 1,2-azole- and pyridine-substituted aromatic aldehydes of the vanillin series with 1,3-cyclohexanedione in methanol in the presence of trimethylamine. Catalytic cyclization using fibrous sulfocationite FIBAN K-1 gave corresponding 1,8-dioxooctahydroxanthenes. [ABSTRACT FROM AUTHOR]

An efficient and environmentally benign one-pot condensation of cyclic diketones, aldehydes and naphthols was achieved with 1,4-diazabicyclo[2-2-2]octane supported on Amberlyst-15 as a novel catalyst, producing a variety of benzoxanthenones in good to excellent yields. The advantages of this multicomponent reaction include the use of a heterogeneous catalyst, solventless conditions and a simple methodology that is atom-economical and results in low E-factor values. A total of 17 xanthene derivatives, including two novel molecules, were synthesized and then characterized. Aromatic aldehydes carrying an electron-withdrawing group provided excellent yields. Appreciable results were also obtained using aliphatic aldehydes. The catalyst is fully recyclable and can be reused up to six times. [ABSTRACT FROM AUTHOR]

G protein-coupled receptors (GPCRs) are membrane proteins that play important roles in biology. However, our understanding of their function in complex living systems is limited because we lack tools that can target individual receptors with sufficient precision. State-of-the-art approaches, including DREADDs, optoXRs, and PORTL gated-receptors, control GPCR signaling with molecular, cell type, and temporal specificity. Nonetheless, these tools are based on engineered non-native proteins that may (i) express at nonphysiological levels, (ii) localize and turnover incorrectly, and/or (iii) fail to interact with endogenous partners. Alternatively, membrane-anchored ligands (t-toxins, DARTs) target endogenous receptors with molecular and cell type specificity but cannot be turned on and off. In this study, we used a combination of chemistry, biology, and light to control endogenous metabotropic glutamate receptor 2 (mGluR2), a Family C GPCR, in primary cortical neurons. mGluR2 was rapidly, reversibly, and selectively activated with photoswitchable glutamate tethered to a genetically targeted-plasma membrane anchor (membrane anchored Photoswitchable Orthogonal Remotely Tethered Ligand; maPORTL). Photoactivation was tuned by adjusting the length of the PORTL as well as the expression level and geometry of the membrane anchor. Our findings provide a template for controlling endogenous GPCRs with cell type specificity and high spatiotemporal precision.

The experimental and theoretical studies of the reactions of 5,5-dimethylcyclohexane-1,3-dione (dimedone) with trimethyl- and triethyl orthoformates under various conditions were carried out. It was demonstrated that in the absence of activators the reactions of substrate with ortho esters proceed exclusively as C-C coupling, and in the presence of Brønsted (H2SO4) or Lewis (BF3·Et2O) acids the formation of both C-C and C-O coupling products is observed. The energy consumptions of all reactions in accordance with proposed mechanisms were estimated using quantum chemical calculations by the B3LYP/6-311++G(d,p) method in terms of PCM/MeCN. [ABSTRACT FROM AUTHOR]

Agar-coated Fe3O4 nanoparticles (Fe3O4@agar) were prepared simply through in situ co-precipitation of Fe2+ and Fe3+ ions via NH4OH in an aqueous solution of Agar. Coating of Ag+ ions on the surface of the latter followed by mild reduction of Ag+ with NaBH4 gives Fe3O4@Agar-Ag NPs. The magnetic Fe3O4@Agar-Ag nanocatalyst was characterized thoroughly by FT‐IR, XRD, SEM, TEM, VSM, EDX, TGA, and ICP analyses. Its catalytic activity was assessed in the synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthene-11-one, 14-aryl-14H-dibenzo[a,j]xanthenes, and 1,8-dioxo-octahydroxanthene derivatives through a one-pot condensation of dimedone, 2-naphthol, and aryl aldehydes in EtOH. This novel method represents lots of advantages compared to the previous researches, such as avoiding the toxic catalysts, easy method for isolation of the products, satisfying yields, totally clean conditions, and simplicity of the methodology. This catalytic system is attributed to an eco-friendly process, high catalytic activity, and facility of recovery using an external magnet. A novel and magnetically recyclable catalyst known as Fe3O4@Agar-Ag NPs as a heterogeneous catalyst were synthesized by a simple method. Using this facile, efficient, and eco-friendly Nanocomposite, for the different models of xanthene reaction was represented. [ABSTRACT FROM AUTHOR]

Ten biologically active derivatives of 2,6,7-trihydroxyxanthen-3-one, previously synthesized and characterised, were investigated for their in vitro antimicrobial and antiproliferative activity. Compounds were tested on three bacteria, Staphylococcus aureus, Bacillus subtilis and Escherichia coli, and two fungi strains, Candida albicans, and Saccharomyces cerevisiae. The best activity against E. coli showed non-substituted compound 1. The most potent against fungi strains was compound 7 with ortho methoxy substituent. Compound 4 exerted the most potent antiproliferative activity in the micromolar range (0.1–10 µM) on tested tumour cell lines except on SW620. Additional Western blot analyses showed increased cyclin B1 levels in HeLa cells treated with compound 4, which is a major mitotic catastrophe’s marker and decreased levels of Wee1 and Erk ½ kinases involved in regulation of the mitotic process. The most potent compounds after in vitro tests were subjected to molecular docking simulations to evaluate enzyme binding affinity, and provide further evidence for experimentally observed biological effects in vitro.

A new heterogeneous catalyst, nanodiatomite@melamine-SO3H, was introduced for synthesizing 1,8‐dioxo-octahydroxanthenes via multicomponent reactions of aldehydes and dimedone. The prepared catalyst was characterized by employing several techniques, including FT-IR, XRD, TGA, EDX, BET, SEM, and TEM. The products were obtained under solvent-free conditions, with high yields in short reaction times. The nanodiatomite@melamine-SO3H was reused five times without substantial activity loss. Nanodiatomite@melamine-SO3H as a novel heterogeneous catalyst was successfully developed and defined through several techniques. The catalyst showed excellent catalytic activity in the xanthene synthesis. The good points of this methodology are ease of product isolation, catalyst efficiency and recycling, cleaner reaction profile, and the procedure agreement with the green chemistry. [ABSTRACT FROM AUTHOR]

Herein, we first report an electrochemical methodology for the site-selective alkylation of azobenzenes with (thio)xanthenes in the absence of any transition metal catalyst or external oxidant. A variety of groups are compatible with this electrochemical alkylation, which furnishes the products in moderate to good yields. [ABSTRACT FROM AUTHOR]

Deep eutectic solvent (DES) catalyzed, Microwave-assisted one-pot conjugate Michael addition followed by annulation of nucleophiles, 4-hydroxy coumarin, 1,3-diketone with α,β-unsaturated carbonyl compounds (chalcones) toward benzopyran, pyranocoumarin, xanthene, dihydrofuran, 4-hydroxy-coumarin (warfarin analogs) derivatives has been achieved. It is a one-pot, solvent, metal-free, and green chemical approach with a clean reaction pathway, in high regio, stereo selectivities, and yields under milder MW-irradiation. The easily recoverable DES catalyst and eco-friendly reaction strategy are notable advantages of the current procedure. [ABSTRACT FROM AUTHOR]

Objective: Solute transport in the brain is essential for maintaining cerebral homeostasis. Recent studies have shown that neuronal activity enhances the transport of cerebrospinal fluid solutes, but its impact on interstitial solute transport has not been established. In this study, we investigated whether neuronal activity affects the transport of interstitial solutes., Methods: Fluorescent Texas Red ovalbumin was injected intracortically into the unilateral sensorimotor area of the Sprague-Dawley rats. Regional neuronal activity around the injection site was elicited by transdermal electrical stimulation of a corresponding forelimb for 90 min ( n  = 6). The control group of rats ( n  = 6) did not receive any electrical stimulation. Subsequently, the spatial distributions of the tracer over the cortical surface and from the brain sections were imaged and compared between two groups. The ovalbumin fluorescence from the cervical lymph nodes was also compared between the groups to evaluate the effect of neuronal activity on solute clearance from the brain., Results: Tracer distribution over the brain surface/sections revealed a significantly higher uptake of ovalbumin in the hemisphere ipsilateral to the injection among the stimulated animals compared to the unstimulated group. This difference, however, was not seen in the hemisphere contralateral to injection. A trace amount of ovalbumin in the lymph nodes was equivalent between the groups, which indicated a considerable time needed for interstitial solutes to be drained from the brain., Conclusion: The results suggest that neuronal activity enhances interstitial solute transport, calling for further examination of ultimate routes and mechanisms for brain solute clearance., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Xanthene derivatives have broad applications in medicines, fluorescent probes, dyes, food additives, etc. Therefore, much attention was focused on developing the synthetic methods to prepare these compounds. Binaphthyl‐based xanthene derivatives were prepared through the oxidation of BINOLs promoted by the hypervalent iodine reagent iodosylbenzene (PhIO). Nine‐membered lactones were obtained through a similar oxidative reaction when iodoxybenzene (PhIO2) was used. Additionally, one‐pot reactions of BINOLs, PhIO and nucleophiles such as alcohols and amines were also investigated to provide alkoxylated products and amides in good to excellent yields. [ABSTRACT FROM AUTHOR]

Spontaneous calcium (Ca) waves in cardiac myocytes underlie delayed afterdepolarizations (DADs) that trigger cardiac arrhythmias. How these subcellular/cellular events overcome source-sink factors in cardiac tissue to generate DADs of sufficient amplitude to trigger action potentials is not fully understood. Here, we evaluate quantitatively how factors at the subcellular scale (number of Ca wave initiation sites), cellular scale (sarcoplasmic reticulum (SR) Ca load), and tissue scale (synchrony of Ca release in populations of myocytes) determine DAD features in cardiac tissue using a combined experimental and computational modeling approach. Isolated patch-clamped rabbit ventricular myocytes loaded with Fluo-4 to image intracellular Ca were rapidly paced during exposure to elevated extracellular Ca (2.7 mmol/L) and isoproterenol (0.25 μmol/L) to induce diastolic Ca waves and subthreshold DADs. As the number of paced beats increased from 1 to 5, SR Ca content (assessed with caffeine pulses) increased, the number of Ca wave initiation sites increased, integrated Ca transients and DADs became larger and shorter in duration, and the latency period to the onset of Ca waves shortened with reduced variance. In silico analysis using a computer model of ventricular tissue incorporating these experimental measurements revealed that whereas all of these factors promoted larger DADs with higher probability of generating triggered activity, the latency period variance and SR Ca load had the greatest influences. Therefore, incorporating quantitative experimental data into tissue level simulations reveals that increased intracellular Ca promotes DAD-mediated triggered activity in tissue predominantly by increasing both the synchrony (decreasing latency variance) of Ca waves in nearby myocytes and SR Ca load, whereas the number of Ca wave initiation sites per myocyte is less important.

Recently, the combined application of synergistic therapies for photodynamic antimicrobial chemotherapy has become important to obtain more efficient results. The synergism between two sensitizers, rose bengal (RB) and chlorin e6 (Ce6), excited by two different methods, was evaluated as a novel approach to both photodynamic and sonodynamic therapy against methicillin-resistant Staphylococcus aureus. The sonostability and singlet oxygen generation (with 1,3-diphenylisobenzofuran for RB and tetrathiafulvalene for Ce6) were measured under sonication (1 MHz, 3 W) using a spectrophotometer. RB and Ce6 remained stable during sonication. RB was a more efficient sonosensitizer than Ce6. The dual synergism between RB and Ce6 was noticed, achieving a >3 log reduction for molar ratios RB:Ce6 of 1:1 and 1:3, while, alone, the sensitizers excited with ultrasound and light, respectively, achieved only ca. a 1 log reduction.

An efficient and environmentally benign one-pot condensation of cyclic diketones, aldehydes and naphthols was achieved with 1,4-diazabicyclo[2-2-2]octane supported on Amberlyst-15 as a novel catalyst, producing a variety of benzoxanthenones in good to excellent yields. The advantages of this multicomponent reaction include the use of a heterogeneous catalyst, solventless conditions and a simple methodology that is atom-economical and results in low E-factor values. A total of 17 xanthene derivatives, including two novel molecules, were synthesized and then characterized. Aromatic aldehydes carrying an electron-withdrawing group provided excellent yields. Appreciable results were also obtained using aliphatic aldehydes. The catalyst is fully recyclable and can be reused up to six times.

Ten biologically active derivatives of 2,6,7-trihydroxyxanthen-3-one, previously synthesized and characterised, were investigated for their in vitro antimicrobial and antiproliferative activity. Compounds were tested on three bacteria, Staphylococcus aureus, Bacillus subtilis and Escherichia coli, and two fungi strains, Candida albicans, and Saccharomyces cerevisiae. The best activity against E. coli showed non-substituted compound 1. The most potent against fungi strains was compound 7 with ortho methoxy substituent. Compound 4 exerted the most potent antiproliferative activity in the micromolar range (0.1–10 μM) on tested tumour cell lines except on SW620. Additional Western blot analyses showed increased cyclin B1 levels in HeLa cells treated with compound 4, which is a major mitotic catastrophe’s marker and decreased levels of Wee1 and Erk ½ kinases involved in regulation of the mitotic process. The most potent compounds after in vitro tests were subjected to molecular docking simulations to evaluate enzyme binding affinity, and provide further evidence for experimentally observed biological effects in vitro. [ABSTRACT FROM AUTHOR]

RationaleCardiac myocyte contraction is caused by Ca(2+) binding to troponin C, which triggers the cross-bridge power stroke and myofilament sliding in sarcomeres. Synchronized Ca(2+) release causes whole cell contraction and is readily observable with current microscopy techniques. However, it is unknown whether localized Ca(2+) release, such as Ca(2+) sparks and waves, can cause local sarcomere contraction. Contemporary imaging methods fall short of measuring microdomain Ca(2+)-contraction coupling in live cardiac myocytes.ObjectiveTo develop a method for imaging sarcomere level Ca(2+)-contraction coupling in healthy and disease model cardiac myocytes.Methods and resultsFreshly isolated cardiac myocytes were loaded with the Ca(2+)-indicator fluo-4. A confocal microscope equipped with a femtosecond-pulsed near-infrared laser was used to simultaneously excite second harmonic generation from A-bands of myofibrils and 2-photon fluorescence from fluo-4. Ca(2+) signals and sarcomere strain correlated in space and time with short delays. Furthermore, Ca(2+) sparks and waves caused contractions in subcellular microdomains, revealing a previously underappreciated role for these events in generating subcellular strain during diastole. Ca(2+) activity and sarcomere strain were also imaged in paced cardiac myocytes under mechanical load, revealing spontaneous Ca(2+) waves and correlated local contraction in pressure-overload-induced cardiomyopathy.ConclusionsMultimodal second harmonic generation 2-photon fluorescence microscopy enables the simultaneous observation of Ca(2+) release and mechanical strain at the subsarcomere level in living cardiac myocytes. The method benefits from the label-free nature of second harmonic generation, which allows A-bands to be imaged independently of T-tubule morphology and simultaneously with Ca(2+) indicators. Second harmonic generation 2-photon fluorescence imaging is widely applicable to the study of Ca(2+)-contraction coupling and mechanochemotransduction in both health and disease.

We report, a novel, green, nano-sized particles as a sandwich nano-capsule multilayer catalyst (SNC@MC) [Fe3O4@Al2O3@SiO2@Fe2O3] for the efficacious one-pot synthesis of 14-aryl-14H- dibenzo[a-j]xanthenes in high yields, under mild and solvent-free conditions at room temperature. The catalyst structure characterized by using various analytical techniques such as SEM, EDS, FT-IR, thermogravimetric analysis (TGA) and UV-visible spectroscopy. Environmentally friendly, availability, high catalytic activity, high efficiency, mild reaction conditions and ease of separation are the main reasons in using this green sandwich nano-capsule multilayer catalyst. [ABSTRACT FROM AUTHOR]

Opioid analgesics are widely used as a treatment option for pain management and relief. However, the misuse of opioid analgesics has contributed to the current opioid epidemic in the United States. Prescribed opioids such as morphine, codeine, oxycodone, and fentanyl are mu-opioid receptor (MOR) agonists primarily used in the clinic to treat pain or during medical procedures, but development of tolerance limits their utility for treatment of chronic pain. Here we explored the effects of biasing G βγ signaling on tolerance development after chronic morphine treatment in vivo. We hypothesized that biasing G βγ signaling with gallein could prevent activation of regulatory signaling pathways that result in tolerance to antinociceptive effects of MOR agonists. Gallein has been shown to bind to G βγ and inhibit interactions of G βγ with phospholipase-C β 3 (PLC β 3) or G-protein-coupled receptor kinase 2 (GRK2) but not G-protein inwardly rectifying potassium (GIRK) channels. In mice, morphine-induced antinociception was evaluated in the 55°C warm water tail withdrawal assay. We used two paradigms for gallein treatment: administration during and after three times-daily morphine administration. Our results show that gallein cotreatment during repeated administration of morphine decreased opioid tolerance development and that gallein treatment in an opioid-tolerant state enhanced the potency of morphine. Mechanistically, our data suggest that PLC β 3 is necessary for potentiating effects of gallein in an opioid-tolerant state but not in preventing the development of tolerance. These studies demonstrate that small molecules that target G βγ signaling could reduce the need for large doses of opioid analgesics to treat pain by producing an opioid-sparing effect. SIGNIFICANCE STATEMENT: Biasing G βγ signaling prevents tolerance to repeated morphine administration in vivo and potentiates the antinociceptive effects of morphine in an opioid-tolerant state. Mechanistically, phospholipase-C β is necessary for potentiating effects of gallein in an opioid-tolerant state but not in preventing the development of tolerance. This study identifies a novel treatment strategy to decrease the development of tolerance to the analgesic effects of mu-opioid receptor agonists, which are necessary to improve pain treatment and decrease the incidence of opioid use disorder., (Copyright © 2024 by The American Society for Pharmacology and Experimental Therapeutics.)

N 2 H 4 is a common raw material used in the production of pesticides and has good water solubility, so it may contaminate water sources and eventually enter living organisms, causing serious health problems. Viscosity is an important indicator of the cellular microenvironment and an early warning signal for many diseases. The high reactivity of hydrazine depletes glutathione (GSH) in hepatocytes, causing oxidative stress ultimately leading to significant changes in intracellular viscosity and even death. Therefore, it is particularly important to develop an effective method to detect N 2 H 4 and viscosity in environmental and biological systems. On this basis, we developed two fluorescent probes, BDD and BHD, based on xanthene and 2-benzothiazole acetonitrile. The experimental results show that BHD and BDD have good imaging capabilities for N 2 H 4 in cells, zebrafish and Arabidopsis. BHD and BDD also showed sensitive detection and fluorescence enhancement in the near-infrared region when the intracellular viscosity was changed. Notably, the probe BDD has also successfully imaged N 2 H 4 in a variety of real water samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

We proposed a new methodology, the microelution ATM/CZA (mATM/CZA), based on the antibiotic disc elution and the use of resazurin, for rapid (<4h) determination of in vitro susceptibility to aztreonam combined with ceftazidime-avibactam among Enterobacterales. The mATM/CZA presented excellent accuracy with 1.9 %, 98.1 % and 100 % of major error, specificity and sensitivity, respectively. Furthermore, we assessed synergism between aztreonam and ceftazidime-avibactam in Enterobacterales and Pseudomonas aeruginosa, which was observed in 37/55 Enterobacterales and 31/56 P. aeruginosa. As reference methodologies (checkerboard, time-kill curve) are not compatible with the routine of the clinical microbiology laboratories, mATM/CZA is an important alternative to evaluate susceptibility of the combination in a scenario where its clinical use is increasingly important., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Mitochondria are important organelles that provide energy for cellular physiological activities. Changes in their structures may indicate the occurrence of diseases, and the super-resolution imaging of mitochondria is of great significance. However, developing fluorescent probes for mitochondrial super-resolution visualization still remains challenging due to insufficient fluorescence brightness and poor stability. Herein, we rationally synthesized an ultrabright xanthene fluorescence probe Me-hNR for mitochondria-specific super-resolution imaging using structured illumination microscopy (SIM). The rigid structure of Me-hNR provided its ultrahigh fluorescence quantum yield of up to 0.92 and ultrahigh brightness of up to 16,000. Occupying the para -position of the O atom in the xanthene skeleton by utilizing the smallest methyl group ensured its excellent stability. The study of the photophysical process indicated that Me-hNR mainly emitted fluorescence via radiative decay, and nonradiative decay and inter-system crossing were rare due to the slow nonradiative decay rate and large energy gap (Δ E s t = 0.55 eV). Owing to these excellent merits, Me-hNR can specifically light up mitochondria at ultralow concentrations down to 5 nM. The unprecedented spatial resolution for mitochondria with an fwhm of 174 nm was also achieved. Therefore, this ultrabright xanthene fluorescence probe has great potential in visualizing the structural changes of mitochondria and revealing the pathogenesis of related diseases using SIM.

Background: Vascular dementia (VaD) is a prevalent neurodegenerative disease characterized by cognitive impairment due to cerebrovascular factors, affecting a significant portion of the aging population and highlighting the critical need to understand specific targets and mechanisms for effective prevention and treatment strategies. We aimed to identify pathways and crucial genes involved in the progression of VaD through bioinformatics analysis and subsequently validate these findings., Methods: We conducted differential expression analysis, Weighted Gene Co-expression Network Analysis (WGCNA), Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and Protein-Protein Interaction (PPI) analysis. We utilized pheochromocytoma 12 (PC12) cells to create an in vitro oxygen-glucose deprivation (OGD) model. We investigated the impact of overexpression and interference of adrenoceptor alpha 1D (ADRA1D) on OGD PC12 cells using TdT-mediated dUTP nick-end labeling (TUNEL), reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blot (WB), and Fluo-3-pentaacetoxymethyl ester (Fluo-3 AM) analysis., Results: We found 187 differentially expressed genes (DEGs) in the red module that were strongly associated with VaD and were primarily enriched in vasoconstriction, G protein-coupled amine receptor activity, and neuroactive ligand-receptor interaction, mitogen-activated protein kinase (MAPK) signaling pathway, and cell adhesion. Among these pathways, we identified ADRA1D as a gene shared by vasoconstriction, G protein-coupled amine receptor activity, and neuroactive ligand-receptor interaction. The TUNEL assay revealed a significant decrease in PC12 cell apoptosis with ADRA1D overexpression (p < 0.01) and a significant increase in apoptosis upon silencing ADRA1D (p < 0.01). RT-qPCR and WB analysis revealed elevated ADRA1D expression (p < 0.001) and decreased phospholipase C beta (PLCβ) and inositol 1,4,5-trisphosphate receptor (IP3R) expression (p < 0.05) with ADRA1D overexpression. Moreover, the Fluo-3 AM assessment indicated significantly lower intracellular Ca2+ levels with ADRA1D overexpression (p < 0.001). Conversely, interference with ADRA1D yielded opposite results., Conclusion: Our study provides a new perspective on the pathogenic mechanisms of VaD and potential avenues for therapeutic intervention. The results highlight the role of ADRA1D in modulating cellular responses to OGD and VaD, suggesting its potential as a target for VaD treatment.

A novel class of rosamine dyes bearing a 7‐substituted 4‐hydroxycoumarin unit as meso‐heteroaryl ring is presented. The latent C‐nucleophilic character of 4‐hydroxycoumarin derivatives (i. e. their C‐3 position as a nucleophilic center) has been drawn on in the design of two unprecedented synthetic routes towards these atypical xanthene dyes. The syntheses are based on an effective formal Knoevenagel condensation with either pyronin derivatives or a mixed bis‐aryl ether bearing both an aldehyde and a masked phenylogous amine, possibly applicable to a wide range of latent cyclic C‐nucleophiles. We also report experimental and theoretical photophysical investigations of these unique coumarin‐pyronin hybrid structures and particularly they form low‐lying quenching states, some dark and demonstrating a twisted intramolecular charge transfer (TICT) nature, depending on the medium (CHCl3 and water). Furthermore, two fluorophore compounds have been applied for imaging in paraformaldehyde‐fixed A549 cells to gain insights into their permeation and localization. [ABSTRACT FROM AUTHOR]

The reaction mechanisms of cyclic 1,3-diketones with trialkyl orthoformates and trimethyl orthoacetate in the absence of activators were theoretically and experimentally studied. The reactions proceed via C-C-coupling of the ionized forms of the reactants giving dialkyl acetals, which further transform into vinyl ethers. The reactions of the latter with ortho esters afford aldehydes (ketones). Related 2-acetylcyclopentanone reacts with trimethyl orthoacetate under argon to form a mixture of methyl enol ethers, whereas in the presence of air oxygen dimethyl glutarate is formed. [ABSTRACT FROM AUTHOR]

Agonist stimulation of G protein-coupled receptors (GPCRs) can transactivate epidermal growth factor receptors (EGFRs), but the precise mechanisms for this transactivation have not been defined. Key to this process is the protease-mediated "shedding" of membrane-tethered ligands, which then activate EGFRs. The specific proteases and the events involved in GPCR-EGFR transactivation are not fully understood. We have tested the hypothesis that transactivation can occur by a membrane-delimited process: direct increase in the activity of membrane type-1 matrix metalloprotease (MMP14, MT1-MMP) by heterotrimeric G proteins, and in turn, the generation of heparin-binding epidermal growth factor (HB-EGF) and activation of EGFR. Using membranes prepared from adult rat cardiac myocytes and fibroblasts, we found that MMP14 activity is increased by angiotensin II, phenylephrine, GTP, and guanosine 5'-O-[γ-thio]triphosphate (GTPγS). MMP14 activation by GTPγS occurs in a concentration- and time-dependent manner, does not occur in response to GMP or adenosine 5'-[γ-thio]triphosphate (ATPγS), and is not blunted by inhibitors of Src, PKC, phospholipase C (PLC), PI3K, or soluble MMPs. This activation is specific to MMP14 as it is inhibited by a specific MMP14 peptide inhibitor and siRNA knockdown. MMP14 activation by GTPγS is pertussis toxin-sensitive. A role for heterotrimeric G protein βγ subunits was shown by using the Gβγ inhibitor gallein and the direct activation of recombinant MMP14 by purified βγ subunits. GTPγS-stimulated activation of MMP14 also results in membrane release of HB-EGF and the activation of EGFR. These results define a previously unrecognized, membrane-delimited mechanism for EGFR transactivation via direct G protein activation of MMP14 and identify MMP14 as a heterotrimeric G protein-regulated effector.

Loperamide is a peripheral opiate agonist that can cause apoptosis and G2/M arrest in human cancer cell lines and may sensitize cells to chemotherapy. The objectives of this study were to investigate the effects of loperamide on viability, apoptosis and cell cycle kinetics in canine cancer cells and to establish whether the drug sensitizes cells to doxorubicin. Cell viability was assessed using Alamar Blue. Cell death and cell cycle were studied using flow cytometry with 7-Aminoactinomycin-D (7-AAD) and propidium iodide (PI), respectively. Loperamide decreased cell viability in a dose-dependent fashion and was most effective against canine osteosarcoma cells. In all cell lines, it induced a dose and time dependent apoptosis and resulted in accumulation in G0/G1. When co-incubated with doxorubicin, loperamide induced a synergistic cell kill in canine carcinoma cells. Investigation is warranted into the role of loperamide in the treatment of canine cancer.

Herein, we first report an electrochemical methodology for the site-selective alkylation of azobenzenes with (thio)xanthenes in the absence of any transition metal catalyst or external oxidant. A variety of groups are compatible with this electrochemical alkylation, which furnishes the products in moderate to good yields.

The efficacy of photodynamic therapy (PDT) depends on the combination of light and a photosensitizer for inactivation of microorganisms. However, finding the ideal conditions for the factors involved in this technique is time and cost-consuming. The rotational composite central design (RCCD) is a tool that can be allied with PDT to achieve precise results within a shorter working time. This study used the response surface methodology to optimize the parameters of PDT mediated by Erythrosine (ERY) and green light-emitting diodes (LED) in different Escherichia coli strains by applying RCCD. The RCCD predicted optimum values of ERY and light exposure on PDT. According to the experimental results, the light exposure time showed the most significant influence on the inactivation of the evaluated bacteria. The optimized operating conditions were validated in laboratory tests, and no viable cells were recovered with ERY at 116 µmol L−1 and 30 min of light (33.34 J cm2) for E. coli ATCC 25922, 108 µmol L−1 and 40 min (44.38 J cm2) for E. coli ATCC 35218, and 108 µmol L−1 and 29.3 min (32.5 J cm2) for E. coli O157:H7 EDL 933. The adjusted polynomial models provided accurate information on the combined effects of ERY and lighting time with green LED on PDT. The application of the RCCD, in addition to reducing the number of experiments, also allows for increased quantity and quality of the results. Therefore, surface response methodology combined with PDT is a promising approach to inactivate E. coli. [ABSTRACT FROM AUTHOR]

The first near-infrared fluorescent turn-on sensor for the detection of nitroxyl (HNO), the one-electron reduced form of nitric oxide (NO), is reported. The new copper-based probe, CuDHX1, contains a dihydroxanthene (DHX) fluorophore and a cyclam derivative as a Cu(II) binding site. Upon reaction with HNO, CuDHX1 displays a five-fold fluorescence turn-on in cuvettes and is selective for HNO over thiols and reactive nitrogen and oxygen species. CuDHX1 can detect exogenously applied HNO in live mammalian cells and in conjunction with the zinc-specific, green-fluorescent sensor ZP1 can perform multicolor/multianalyte microscopic imaging. These studies reveal that HNO treatment elicits an increase in the concentration of intracellular mobile zinc.

IntroductionAlthough adenosine triphosphate (ATP) has often been reported to relax the corpus cavernosum, this may be mediated by indirect effects, such as release of nitric oxide from the endothelium. Recent data suggest that P2X(1) receptors may be up-regulated in diabetes, and these exert an anti-erectile effect by causing the corpus cavernosum smooth muscle cells (CCSMCs) to contract. However, to date, there is no functional evidence that ATP can directly stimulate CCSMC.AimsThis study aims to (i) to directly examine the effect of ATP on membrane currents in freshly isolated CCSMC, where influences of endothelium and other cells are absent; and (ii) to determine the receptor subtypes, ionic currents, and Ca(2+) signals stimulated by ATP.MethodsCCSMCs were enzymatically dispersed from male New Zealand White rabbits for patch clamp recording and measurement of intracellular Ca(2+) in fluo-4-loaded cells using spinning disk confocal microscopy.Main outcome measuresPatch clamp recordings were made of ATP-evoked membrane currents and spontaneous membrane currents. Spinning disk confocal imaging of intracellular Ca(2+) was performed, and the response to ATP was recorded.ResultsATP evoked repeatable inward currents in CCSMC (1st application: -675 ± 101 pA; 2nd application: -694 ± 120 pA, N = 9, P = 0.77). ATP-induced currents were reduced by suramin from -380 ± 121 to -124 ± 37 pA (N = 8, P

IntroductionAlthough adenosine triphosphate (ATP) has often been reported to relax the corpus cavernosum, this may be mediated by indirect effects, such as release of nitric oxide from the endothelium. Recent data suggest that P2X(1) receptors may be up-regulated in diabetes, and these exert an anti-erectile effect by causing the corpus cavernosum smooth muscle cells (CCSMCs) to contract. However, to date, there is no functional evidence that ATP can directly stimulate CCSMC.AimsThis study aims to (i) to directly examine the effect of ATP on membrane currents in freshly isolated CCSMC, where influences of endothelium and other cells are absent; and (ii) to determine the receptor subtypes, ionic currents, and Ca(2+) signals stimulated by ATP.MethodsCCSMCs were enzymatically dispersed from male New Zealand White rabbits for patch clamp recording and measurement of intracellular Ca(2+) in fluo-4-loaded cells using spinning disk confocal microscopy.Main outcome measuresPatch clamp recordings were made of ATP-evoked membrane currents and spontaneous membrane currents. Spinning disk confocal imaging of intracellular Ca(2+) was performed, and the response to ATP was recorded.ResultsATP evoked repeatable inward currents in CCSMC (1st application: -675 ± 101 pA; 2nd application: -694 ± 120 pA, N = 9, P = 0.77). ATP-induced currents were reduced by suramin from -380 ± 121 to -124 ± 37 pA (N = 8, P

Islet amyloid polypeptide (IAPP) is responsible for amyloid formation in type 2 diabetes and contributes to the failure of islet cell transplants, however the mechanisms of IAPP-induced cytotoxicity are not known. Interactions with model anionic membranes are known to catalyze IAPP amyloid formation in vitro. Human IAPP damages anionic membranes, promoting vesicle leakage, but the features that control IAPP-membrane interactions and the connection with cellular toxicity are not clear. Kinetic studies with wild-type IAPP and IAPP mutants demonstrate that membrane leakage is induced by prefibrillar IAPP species and continues over the course of amyloid formation, correlating additional membrane disruption with fibril growth. Analyses of a set of designed mutants reveal that membrane leakage does not require the formation of β-sheet or α-helical structures. A His-18 to Arg substitution enhances leakage, whereas replacement of all of the aromatic residues via a triple leucine mutant has no effect. Biophysical measurements in conjunction with cytotoxicity studies show that nonamyloidogenic rat IAPP is as effective as human IAPP at disrupting standard anionic model membranes under conditions where rat IAPP does not induce cellular toxicity. Similar results are obtained with more complex model membranes, including ternary systems that contain cholesterol and are capable of forming lipid rafts. A designed point mutant, I26P-IAPP; a designed double mutant, G24P, I26P-IAPP; a double N-methylated variant; and pramlintide, a US Food and Drug Administration-approved IAPP variant all induce membrane leakage, but are not cytotoxic, showing that there is no one-to-one relationship between disruption of model membranes and induction of cellular toxicity.

Simple and green procedure was developed for the synthesis of various xanthene and coumarin derivatives using beta-cyclodextrin (β-CD) as reusable catalyst at 70 °C in water. Condensation of salicylaldehyde (1 mmol) and dimedone (2 mmol) or 1,3 cyclohexadione (2 mmol) gave corresponding xanthene derivatives, while condensation of salicylaldehyde (1 mmol) with Meldrum's acid (1 mmol) or 4-Hydroxy-6-methyl-2H-pyran-2-one (1 mmol) gave respective coumarin derivatives in impressive yields. Involvement of β-CD as catalyst was ascertained by inclusion complex evaluation of β-CD-salicylaldehyde with 1H NMR analysis at 70 °C. [ABSTRACT FROM AUTHOR]

An efficient CAN‐mediated C−C bond formation in the oxidative reactions of xanthenes with enaminones under mild reaction conditions are described. A variety of 9H‐xanthene‐9‐ylidene aldehydes could be synthesized in up to 90% yield via one‐pot manner with good functional group compatibility, which achieved the simultaneous construction of carbon‐carbon double bond and carbon‐oxygen double bond. [ABSTRACT FROM AUTHOR]

Nowadays, leishmaniasis constitutes a public health issue in more than 88 countries, affecting mainly people from the tropics, subtropics, and the Mediterranean area. Every year, the prevalence of this infectious disease increases, with the appearance of 1.5–2 million new cases of cutaneous leishmaniasis and 500,000 cases of visceral leishmaniasis, endangering approximately 350 million people worldwide. Therefore, the absence of a vaccine or effective treatment makes the discovery and development of new antileishmanial therapies one of the focuses for the scientific community that, in association with WHO, hopes to eradicate this disease shortly. This paper is intended to highlight the relevance of nitrogen- and oxygen-containing tricyclic heterocycles, particularly acridine and xanthene derivatives, for the development of treatments against leishmaniasis. Thus, in this review, a thorough compilation of the most promising antileishmanial acridine and xanthene derivatives is performed from both natural and synthetic origins. Additionally, some structure–activity relationship studies are also depicted and discussed to provide insight into the optimal structural features responsible for these compounds’ antileishmanial activity.

The resazurin assay, also known as the Alamar Blue assay, stands as a cornerstone technique in cell biology, microbiology, and drug development. It assesses the viability of cells through the conversion of resazurin into highly fluorescent resorufin. The resulting fluorescence intensity provides a reliable estimate of viable cell numbers. Cytotoxicity assays, such as the resazurin-based method, play a crucial role in the screening of potential drug candidates and in the assessment of pharmaceutical and chemical toxicity. In recent years, inconsistencies have arisen in pharmacogenomic studies, often due to poorly optimized laboratory protocols. These inconsistencies hinder progress in understanding how substances affect cell health, leading to unreliable findings. Thus, the need for standardized and rigorously optimized protocols is evident to ensure consistent and accurate results in cytotoxicity studies. This manuscript describes a standardized procedure for optimizing resazurin-based viability assays to improve the reliability of cytotoxicity data. This optimization approach focuses on critical experimental parameters and data quality, aiming to achieve a level of measurement imprecision of less than 20%. In conclusion, to address the critical issues of reproducibility and reliability, protocol standardization, such as the one described in this manuscript, can greatly enhance the credibility of cytotoxicity studies, ultimately advancing drug safety assessments.