Ligand recognition and allosteric regulation of DRD1-Gs signaling complexes.

Dopamine receptors, including D1- and D2-like receptors, are important therapeutic targets in a variety of neurological syndromes, as well as cardiovascular and kidney diseases. Here, we present five cryoelectron microscopy (cryo-EM) structures of the dopamine D1 receptor (DRD1) coupled to Gs heterotrimer in complex with three catechol-based agonists, a non-catechol agonist, and a positive allosteric modulator for endogenous dopamine. These structures revealed that a polar interaction network is essential for catecholamine-like agonist recognition, whereas specific motifs in the extended binding pocket were responsible for discriminating D1- from D2-like receptors. Moreover, allosteric binding at a distinct inner surface pocket improved the activity of DRD1 by stabilizing endogenous dopamine interaction at the orthosteric site. DRD1-Gs interface revealed key features that serve as determinants for G protein coupling. Together, our study provides a structural understanding of the ligand recognition, allosteric regulation, and G protein coupling mechanisms of DRD1.

CD1a on Langerhans cells controls inflammatory skin disease.

CD1a is a lipid-presenting molecule that is abundantly expressed on Langerhans cells. However, the in vivo role of CD1a has remained unclear, principally because CD1a is lacking in mice. Through the use of mice with transgenic expression of CD1a, we found that the plant-derived lipid urushiol triggered CD1a-dependent skin inflammation driven by CD4(+) helper T cells that produced the cytokines IL-17 and IL-22 (TH17 cells). Human subjects with poison-ivy dermatitis had a similar cytokine signature following CD1a-mediated recognition of urushiol. Among various urushiol congeners, we identified diunsaturated pentadecylcatechol (C15:2) as the dominant antigen for CD1a-restricted T cells. We determined the crystal structure of the CD1a-urushiol (C15:2) complex, demonstrating the molecular basis of urushiol interaction with the antigen-binding cleft of CD1a. In a mouse model and in patients with psoriasis, CD1a amplified inflammatory responses that were mediated by TH17 cells that reacted to self lipid antigens. Treatment with blocking antibodies to CD1a alleviated skin inflammation. Thus, we propose CD1a as a potential therapeutic target in inflammatory skin diseases.

A genome assembly of ginger (Zingiber officinale Roscoe) provides insights into genome evolution and 6-gingerol biosynthesis.

Ginger is cultivated in tropical and subtropical regions and is one of the most crucial spices worldwide owing to its special taste and scent. Here, we present a high-quality genome assembly for 'Small Laiwu Ginger', a famous cultivated ginger in northern China. The ginger genome was phased into two haplotypes, haplotype A (1.55Gb), and haplotype B (1.44Gb). Analysis of Ty1/Copia and Ty3/Gypsy LTR retrotransposon families revealed that both have undergone multiple retrotransposon bursts about 0-1 million years ago. In addition to a recent whole-genome duplication event, there has been a lineage-specific expansion of genes involved in stilbenoid, diarylheptanoid, and gingerol biosynthesis, thereby enhancing 6-gingerol biosynthesis. Furthermore, we focused on the biosynthesis of 6-gingerol, the most important gingerol, and screened key transcription factors ZoMYB106 and ZobHLH148 that regulate 6-gingerol synthesis by transcriptomic and metabolomic analysis in the ginger rhizome at four growth stages. The results of yeast one-hybrid, electrophoretic mobility shift, and dual-luciferase reporter gene assays showed that both ZoMYB106 and ZobHLH148 bind to the promoters of the key rate-limiting enzyme genes ZoCCOMT1 and ZoCCOMT2 in the 6-gingerol synthesis pathway and promote their transcriptional activities. The reference genome, transcriptome, and metabolome data pave the way for further research on the molecular mechanism underlying the biosynthesis of 6-gingerol. Furthermore, it provides precious new resources for the study on the biology and molecular breeding of ginger.

The photoprotection mechanism in the black-brown pigment eumelanin.

The natural black-brown pigment eumelanin protects humans from high-energy UV photons by absorbing and rapidly dissipating their energy before proteins and DNA are damaged. The extremely weak fluorescence of eumelanin points toward nonradiative relaxation on the timescale of picoseconds or shorter. However, the extreme chemical and physical complexity of eumelanin masks its photoprotection mechanism. We sought to determine the electronic and structural relaxation pathways in eumelanin using three complementary ultrafast optical spectroscopy methods: fluorescence, transient absorption, and stimulated Raman spectroscopies. We show that photoexcitation of chromophores across the UV-visible spectrum rapidly generates a distribution of visible excitation energies via ultrafast internal conversion among neighboring coupled chromophores, and then all these excitations relax on a timescale of ∼4 ps without transferring their energy to other chromophores. Moreover, these picosecond dynamics are shared by the monomeric building block, 5,6-dihydroxyindole-2-carboxylic acid. Through a series of solvent and pH-dependent measurements complemented by quantum chemical modeling, we show that these ultrafast dynamics are consistent with the partial excited-state proton transfer from the catechol hydroxy groups to the solvent. The use of this multispectroscopic approach allows the minimal functional unit in eumelanin and the role of exciton coupling and excited-state proton transfer to be determined, and ultimately reveals the mechanism of photoprotection in eumelanin. This knowledge has potential for use in the design of new soft optical components and organic sunscreens.

Eukaryotic catecholamine hormones influence the chemotactic control of Vibrio campbellii by binding to the coupling protein CheW.

SignificanceHost-emitted stress hormones significantly influence the growth and behavior of various bacterial species; however, their cellular targets have so far remained elusive. Here, we used customized probes and quantitative proteomics to identify the target of epinephrine and the α-adrenoceptor agonist phenylephrine in live cells of the aquatic pathogen Vibrio campbellii. Consequently, we have discovered the coupling protein CheW, which is in the center of the chemotaxis signaling network, as a target of both molecules. We not only demonstrate direct ligand binding to CheW but also elucidate how this affects chemotactic control. These findings are pivotal for further research on hormone-specific effects on bacterial behavior.

Comparing in planta accumulation with microbial routes to set targets for a cost-competitive bioeconomy.

Plants and microbes share common metabolic pathways for producing a range of bioproducts that are potentially foundational to the future bioeconomy. However, in planta accumulation and microbial production of bioproducts have never been systematically compared on an economic basis to identify optimal routes of production. A detailed technoeconomic analysis of four exemplar compounds (4-hydroxybenzoic acid [4-HBA], catechol, muconic acid, and 2-pyrone-4,6-dicarboxylic acid [PDC]) is conducted with the highest reported yields and accumulation rates to identify economically advantaged platforms and breakeven targets for plants and microbes. The results indicate that in planta mass accumulation ranging from 0.1 to 0.3 dry weight % (dwt%) can achieve costs comparable to microbial routes operating at 40 to 55% of maximum theoretical yields. These yields and accumulation rates are sufficient to be cost competitive if the products are sold at market prices consistent with specialty chemicals ($20 to $50/kg). Prices consistent with commodity chemicals will require an order-of-magnitude-greater accumulation rate for plants and/or yields nearing theoretical maxima for microbial production platforms. This comparative analysis revealed that the demonstrated accumulation rates of 4-HBA (3.2 dwt%) and PDC (3.0 dwt%) in engineered plants vastly outperform microbial routes, even if microbial platforms were to reach theoretical maximum yields. Their recovery and sale as part of a lignocellulosic biorefinery could enable biofuel prices to be competitive with petroleum. Muconic acid and catechol, in contrast, are currently more attractive when produced microbially using a sugar feedstock. Ultimately, both platforms can play an important role in replacing fossil-derived products.

[6]-Shogaol Induces Apoptosis of Murine Bladder Cancer Cells.

BACKGROUND/AIMS: Bladder cancer is considered one of the most aggressive neoplasms due to its recurrence and progression profile, and even with the improvement in diagnosis and treatment methods, the mortality rate has not shown a declining trend in recent decades. From this perspective, the search and development of more effective and safer therapeutic alternatives are necessary. Phytochemicals are excellent sources of active principles with therapeutic potential. [6]-Shogaol is a phenolic compound extracted from the ginger rhizomes that has shown antitumor effects in a wide variety of cancer models. However, there is no record in the literature of studies reporting these effects in models of bladder cancer. Thus, this study aimed to investigate the in vitro cytotoxic and pro-apoptotic potential of [6]-Shogaol against murine bladder cancer urothelial cells (MB49). METHODS: The cytotoxic effects of [6]-Shogaol on cell viability (MTT method), cell morphology (light microscopy), alteration of proliferative processes (clonogenic assay), oxidative stress pathway (levels of reactive oxygen species) and the induction of apoptotic events (flow cytometry and high-resolution epifluorescence imaging) were evaluated in murine urothelial bladder cancer cell lines (MB49), relative to non-tumor murine fibroblasts (L929). RESULTS: The results showed that [6]-Shogaol was able to induce concentration-dependent cytotoxic effects, which compromised cell viability, exhibiting an inhibitory concentration of 50% of cells (IC50) of 146.8 µM for MB49 tumor cells and 236.0 µM for L929 non-tumor fibroblasts. In addition to inhibiting and altering the proliferative processes if colony formation, it presented pro-apoptotic activity identified through a quantitative analysis and the observation of apoptotic phenotypes, events apparently mediated by the induction of nuclear fragmentation. CONCLUSION: The data presented suggest that [6]-Shogaol has a higher concentration-dependent cytotoxic and apoptosis-inducing potential in MB49 cells than in L929 fibroblasts. These results may contribute to the development of therapeutic alternatives for bladder cancer.

Metabolism of toxic benzonitrile and hydroxybenzonitrile isomers via several distinct central pathway intermediates in a catabolically robust Burkholderia sp.

Aromatic nitriles are of considerable environmental concern, because of their hazardous impacts on the health of both humans and wildlife. In the present study, Burkholderia sp. strain BC1 was observed to be capable of utilizing toxic benzonitrile and hydroxybenzonitrile isomers singly, as sole carbon and energy sources. The results of chromatographic and spectrometric analyses in combination with oxygen uptake and enzyme activity studies, revealed the metabolism of benzonitrile as well as 2-, 3-, and 4-hydroxybenzonitriles by nitrile hydratase-amidase to the corresponding carboxylates. These carboxylates were further metabolized via central pathways, namely benzoate-catechol, salicylate-catechol, 3-hydroxybenzoate-gentisate and 4-hydroxybenzoate-protocatechute pathways in strain BC1, ultimately leading to the TCA cycle intermediates. Studies also evaluated substrate specificity profiles of both nitrile hydratase and amidase(s) involved in the denitrification of the nitriles. In addition, a few metabolic crosstalk events due to the induction of multiple operons by central metabolites were appraised in strain BC1. The present study illustrates the broad degradative potential of strain BC1, harboring diverse catabolic machinery of biotechnological importance, elucidating pathways for the assimilation of benzonitrile and that of hydroxybenzonitrile isomers for the first time.

6-Gingerol alleviates ectopic lipid deposition in skeletal muscle by regulating CD36 translocation and mitochondrial function.

Ectopic lipid deposition (ELD) and mitochondrial dysfunction are common causes of metabolic disorders in humans. Consuming too much fructose can result in mitochondrial dysfunction and metabolic disorders. 6-Gingerol, the main component of ginger (Zingiber officinale Roscoe), has been proven to alleviate metabolic disorders. This study seeks to examine the effects of 6-gingerol on metabolic disorders caused by fructose and uncover the underlying molecular mechanisms. In this study, the results showed that 6-Gingerol ameliorated high-fructose-induced metabolic disorders. Moreover, it inhibited CD36 membrane translocation, increased CD36 expression in the mitochondria, and decreased the O-GlcNAc modification of CD36 and OGT expression in vitro and vivo. In addition, 6-Gingerol enhanced the performance of mitochondria in the skeletal muscle and boosted the respiratory capability of L6 myotubes. This study provides a theoretical basis and new insights for the development of lipid-lowering drugs in clinical practice.

Disposable biosensor based on nanodiamond particles, ionic liquid and poly-l-lysine for determination of phenolic compounds.

This study describes the development of a highly sensitive amperometric biosensor for the analysis of phenolic compounds such as catechol. The biosensor architecture is based on the immobilization of tyrosinase (Tyr) on a screen-printed carbon electrode (SPE) modified with nanodiamond particles (ND), 1-butyl-3-methylimidazolium hexafluorophosphate (IL) and poly-l-lysine (PLL). Surface morphologies of the electrodes during the modification process were evaluated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical characteristics of the modified electrodes. Owing to the synergistic effect of the modification materials, the Tyr/PLL/ND-IL/SPE exhibited high sensitivity (328.2 µA mM-1) towards catechol with a wide linear range (5.0 × 10-8 - 1.2 × 10-5 M) and low detection limit (1.1 × 10-8 M). Furthermore, the method demonstrated good reproducibility and stability. The amperometric response of the biosensor towards other phenolic compounds such as bisphenol A, phenol, p-nitrophenol, m-cresol, p-cresol and o-cresol was also investigated. The analytical applicability of the biosensor was tested by the analysis of catechol in tap water. The results of the tap water analysis showed that the Tyr/PLL/ND-IL/SPE can be used as a practical and effective method for catechol determination.

Biodegradation of chloroethene compounds under microoxic conditions.

The biodegradation of chloroethene compounds under oxic and anoxic conditions is well established. However, the biological reactions that take place under microoxic conditions are unknown. Here, we report the biostimulated (BIOST: addition of lactate) and natural attenuated (NAT) degradation of chloroethene compounds under microoxic conditions by bacterial communities from chloroethene compounds-contaminated groundwater. The degradation of tetrachloroethene was significantly higher in NAT (15.14% on average) than in BIOST (10.13% on average) conditions at the end of the experiment (90 days). Sporomusa, Paracoccus, Sedimentibacter, Pseudomonas, and Desulfosporosinus were overrepresented in NAT and BIOST compared to the source groundwater. The NAT metagenome contains phenol hydrolase P1 oxygenase (dmpL), catechol-1,2-dioxygenase (catA), catechol-2,3-dioxygenases (dmpB, todE, and xylE) genes, which could be involved in the cometabolic degradation of chloroethene compounds; and chlorate reductase (clrA), that could be associated with partial reductive dechlorination of chloroethene compounds. Our data provide a better understanding of the bacterial communities, genes, and pathways potentially implicated in the reductive and cometabolic degradation of chloroethene compounds under microoxic conditions.

Stabilization and Reduced Cytotoxicity of Amyloid Beta Aggregates in the Presence of Catechol Neurotransmitters.

Oligomeric aggregates of the amyloid-beta (Aß) peptide have been implicated as the toxic species for Alzheimer's disease by contributing to oxidative cytotoxicity and physical disruption in cell membranes in the brain. Recent evidence points to the ability of the catecholamine neurotransmitter dopamine in the presence of copper ions to both stabilize oligomers and decrease the toxic effects of these oligomers. Based on these results, physical characterization of aggregates and subsequent cell studies with a neuroblastoma line were performed that show both dopamine and the related neurotransmitter, norepinephrine, can stabilize oligomers and decrease toxicity of Aß aggregates without copper present. To investigate this reduction of toxicity, structural characterization of oligomers in the presence of neurotransmitters was compared to aggregates formed with Aß alone. Gel electrophoresis and transmission electron microscopy show higher levels of oligomers in the presence of dopamine and norepinephrine, yet the oligomer structure is largely amorphous. Aß aggregated alone forms the predicted highly organized fibrillar species, with increased levels of dityrosine covalent linkages, which are largely absent in the presence of the neurotransmitters. A proposed mechanism for the observed decrease in cell death by Aß in the presence of dopamine and norepinephrine suggests the neurotransmitters both block the formation of organized oligomer structures and dityrosine stabilizing linkages while also behaving as antioxidants, providing a dual mechanism for increased cell viability.

Oxidation of dopamine and related catechols in dopaminergic brain regions in Parkinson's disease and during ageing in non-Parkinsonian subjects.

The present study was performed to examine if catechol oxidation is higher in brains from patients with Parkinson's disease compared to age-matched controls, and if catechol oxidation increases with age. Brain tissue from Parkinson patients and age-matched controls was examined for oxidation of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and 3,4-dihydroxyphenylalanine (DOPA) to corresponding quinones, by measurement of 5-S-cysteinyl-dopamine, 5-S-cysteinyl-DOPAC and 5-S-cysteinyl-DOPA. The cysteinyl catechols are assumed to be biomarkers for DA, DOPAC and DOPA autoxidation and part of the biosynthetic pathway of neuromelanin. The concentrations of the 5-S-cysteinyl catechols were lower, whereas the 5-S-cysteinyl-DA/DA and 5-S-cysteinyl-DOPAC/DOPAC ratios tended to be higher in the Parkinson group compared to controls, which was interpreted as a higher degree of oxidation. High 5-S-cysteinyl-DA/DA ratios were found in the substantia nigra of a sub-population of the Parkinson group. Based on 5-S-cysteinyl-DA/DA ratios, dopamine oxidation was found to increase statistically significantly with age in the caudate nucleus, and non-significantly in the substantia nigra. In conclusion, the occurrence of 5-S-cysteinyl-DA, 5-S-cysteinyl-DOPAC and 5-S-cysteinyl-DOPA was demonstrated in dopaminergic brain areas of humans, a tendency for higher oxidation of DA in the Parkinson group compared to controls was observed as well as a statistically significant increase in DA oxidation with age. Possibly, autoxidation of DA and other catechols are involved in both normal and pathological ageing of the brain. This study confirms one earlier but small study, as well as complements one study on non-PD cases and one study on both PD cases and controls on NM bound or integrated markers or catechols.

Novel Type of Slowly Digested Starch Complex with Antioxidant Properties.

With the increasing number of diabetic patients in the world, there is an urgent requirement to reduce the incidence of diabetes. It is considered that a viable prophylactic treatment for type 2 diabetes mellitus is to reduce starch digestibility and oxidative stress. In this study, a novel type of slowly digested starch [pea starch (PS)-gingerol complex] was fabricated to evaluate its in vitro enzymatic digestibility and antioxidant activities. Theoretical and experimental analyses showed that PS can encapsulate gingerols with long alkyl chains to form starch-gingerol complexes, which are further stacked into a mixture of V6- and V7-crystallites. These complexes, in particular the PS-10-gingerol complex, showed high resistance to amylolysis and good antioxidant activities. This study demonstrates that these novel starch-gingerol complexes have the potential to deliver antioxidants encapsulated in starch with slow-digesting properties and reduce oxidative stress. Moreover, this new type of slowly digested starch with antioxidant properties showed great potential in the prevention of type 2 diabetes.

Robust Chemical Synthesis of "Difficult Peptides" via 2-Hydroxyphenol-pseudoproline (ψ2-hydroxyphenolpro) Modifications.

The challenging preparation of "difficult peptides" has always hindered the development of peptide-active pharmaceutical ingredients. Pseudoproline (ψpro) building blocks have been proven effective and powerful tools for the synthesis of "difficult peptides". In this paper, we efficiently prepared a set of novel 2-(oxazolidin-2-yl)phenol compounds as proline surrogates (2-hydroxyphenol-pseudoprolines, ψ2-hydroxyphenolpro) and applied it in the synthesis of many well-known "difficult peptides", including human thymosin α1, amylin, and ß-amyloid (1-42) (Aß42).

o-Semiquinone Radical and o-Benzoquinone Selectively Degrade Aniline Contaminants in the Periodate-Mediated Advanced Oxidation Process.

Advanced oxidation processes (AOPs) often employ strong oxidizing inorganic radicals (e.g., hydroxyl and sulfate radicals) to oxidize contaminants in water treatment. However, the water matrix could scavenge the strong oxidizing radicals, significantly deteriorating the treatment efficiency. Here, we report a periodate/catechol process in which reactive quinone species (RQS) including the o-semiquinone radical (o-SQ•-) and o-benzoquinone (o-Q) were dominant to effectively degrade anilines within 60 s. The second-order reaction rate constants of o-SQ•- and o-Q with aniline were determined to be 1.0 × 108 and 4.0 × 103 M-1 s-1, respectively, at pH 7.0, which accounted for 21% and 79% of the degradation of aniline with a periodate-to-catechol molar ratio of 1:1. The major byproducts were generated via addition or polymerization. The RQS-based process exhibited excellent anti-interference performance in the degradation of aniline-containing contaminants in real water samples in the presence of diverse inorganic ions and organics. Subsequently, we extended the RQS-based process by employing tea extract and dissolved organic matter as catechol replacements as well as metal ions [e.g., Fe(III) or Cu(II)] as periodate replacements, which also exhibited good performance in aniline degradation. This study provides a novel strategy to develop RQS-based AOPs for the highly selective degradation of aniline-containing emerging contaminants.

Levodopa-Carbidopa-Entacapone Intestinal Gel in Advanced Parkinson Disease: A Multicenter Real-Life Experience.

BACKGROUND: For Parkinson disease (PD) patients who have been diagnosed with advanced disease that can no longer be effectively controlled with optimized oral or transdermal medications, a range of device-aided therapies (DAT) are available, comprising either deep brain stimulation or infusion therapies providing continuous dopaminergic stimulation. Levodopa-entacapone-carbidopa intestinal gel (LECIG) infusion is the latest DAT for advanced PD (APD) that was approved in Romania in 2021. STUDY QUESTION: What is the experience to date in real-world clinical practice in Romania regarding the efficacy and tolerability of LECIG in APD? STUDY DESIGN: A retrospective evaluation of 74 APD patients treated with LECIG at 12 specialized APD centers in Romania. MEASURES AND OUTCOMES: Demographic data and various clinical parameters were recorded, including Mini Mental State Evaluation score or Montreal Cognitive Assessment Test score. Levodopa-equivalent daily dose and the administered doses of levodopa and other PD medications were evaluated at baseline and after starting LECIG treatment. The efficacy of LECIG in reducing daily hours of off time, motor fluctuations, and dyskinesias were assessed. Any percutaneous endoscopic gastrojejunostomy system or device complications after starting LECIG treatment were noted. RESULTS: At baseline, patients were taking oral levodopa for a mean of 5.3 times per day, with a high proportion also taking concomitant add-on therapies (dopamine agonists, 86%, monoamine oxidase type-B inhibitors, 53%; catechol-O-methyltransferase inhibitors, 64%). LECIG treatment significantly reduced daily off time versus baseline from 5.7 h/d to 1.7 hours per day ( P < 0.01). Duration and severity of dyskinesias was also significantly reduced versus baseline, and improvements were observed in Hoehn and Yahr Scale scores. LECIG treatment also allowed a significant reduction in the use of concomitant oral medications. CONCLUSIONS: These findings suggest that LECIG treatment is an effective DAT option in APD that can simplify the treatment regimen.

Structural modification of natural axinelline A: Achieving reduced colitis side effects through balanced COX inhibition.

Marine natural products continue to hold great promise as potential candidates for the discovery of anti-inflammatory drug. In our previous investigation, we successfully synthesized axinelline A, a naturally occurring cyclooxygenase-2 (COX-2) inhibitor, as a promising anti-inflammatory lead compound. This study was to discover novel COX inhibitors with balanced inhibition, aiming to mitigate the severe adverse effects through further structural modification of axinelline A. Of the synthetic derivatives, compound 5e showed highest COX-2 inhibitory activity and balanced COX inhibition (IC50 = 1.74 µM; selectivity ((IC50 (COX-1)/IC50(COX-2) = 16.32). The in vitro anti-inflammatory results indicated that 5e effectively suppressed the expression of pro-inflammatory mediators via the NF-κB signaling pathway rather than the MAPK signaling pathway. The in vivo ulcerative colitis assay demonstrated 5e significantly ameliorated the histological damages and showed strong protection against DSS-induced acute colitis. Therefore, our findings suggest that compound 5e exhibits potential as a promising anti-inflammatory agent with attenuated colitis-related adverse effects.

Microbial synthesis of antimony sulfide to prepare catechol and hydroquinone electrochemical sensor by pyrolysis and carbonization.

The application of antimony sulfide sensors, characterized by their exceptional stability and selectivity, is of emerging interest in detection research, and the integration of graphitized carbon materials is expected to further enhance their electrochemical performance. This study represents a pioneering effort in the synthesis of carbon-doped antimony sulfide materials through the pyrolysis of the mixture of microorganisms and their synthetic antimony sulfide. The prepared materials are subsequently applied to electrochemical sensors for monitoring the highly toxic compounds catechol (CC) and hydroquinone (HQ) in the environment. Via cyclic voltammetry (CV) and impedance testing, we concluded that the pyrolytic product at 700 °C (Sb-700) demonstrated the best electrochemical properties. Differential pulse voltammetry (DPV) revealed impressive separation when utilizing Sb-700/GCE for simultaneous detection of CC and HQ, exhibiting good linearity within the concentration range of 0.1-140 µM. The achieved sensitivities of 24.62 µA µM-1 cm-2 and 22.10 µA µM-1 cm-2 surpassed those of most CC and HQ electrochemical sensors. Meanwhile, the detection limits for CC and HQ were as low as 0.18 µM and 0.16 µM (S/N = 3), respectively. Additional tests confirmed the good selectivity, reproducibility, and long-term stability of Sb-700/GCE, which was effective in detecting CC and HQ in tap water and river water, with recovery rates of 100.7%-104.5% and 96.5%-101.4%, respectively. It provides a method that combines green microbial synthesis and simple pyrolysis for the preparation of electrode materials in CC and HQ electrochemical sensors, and also offers a new perspective for the application of microbial synthesized materials.

Spasmolytic Effect of Flopropione Does Not Involve Catechol-O- methyltransferase (COMT) Inhibition.

Flopropione (Flo) has been used for gallstone and urolithiasis as a spasmolytic agent almost exclusively in Japan. According to the package insert, its main mechanism is catechol-O-methyltransferase (COMT) inhibition and anti-serotonergic effect. This is obviously contrary to pharmacological common sense, but it is described that way in pharmacology textbooks and occurs in questions in the National Examination for Pharmacists in Japan. As this is a serious problem in education, we re-examined the action of Flo. The guinea pig ureter was hardly contracted by serotonin, but noradrenaline (NA) elicited repetitive twitch contraction, which was inhibited by Flo. The sphincter of Oddi (SO) exhibited a spontaneous repetitive twitch contraction, which was inhibited by NA and Flo. The inhibitory effect of NA was reversed by α- and ß-blockers, whereas that of Flo was not. Entacapone, a representative COMT inhibitor, did not affect the movement of the ureter and the SO. Nifedipine suppressed carbachol-induced contraction of the taenia coli, spontaneous movement of the SO, and NA-induced contraction of the ureter to almost the same extent, whereas Flo did not inhibit the taenia coli, but inhibited the contraction of the SO and the ureter. The inhibitory pattern of Flo resembled that of the ryanodine receptor agonist 4-chloro-m-cresol and the inositol 1,4,5-trisphosphate (IP3) receptor antagonist 2-aminoethoxydiphenyl borate. It is concluded that COMT inhibition or serotonin inhibition is not involved in the spasmolytic action of Flo. Flo might act on ryanodine receptors and/or IP3 receptors, which are responsible for periodic Ca release from Ca stores, to disrupt coordinated Ca dynamics.