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PLoS Computational Biology Oct 2022Calmodulin (CaM) is a calcium sensor which binds and regulates a wide range of target-proteins. This implicitly enables the concentration of calcium to influence many...
Calmodulin (CaM) is a calcium sensor which binds and regulates a wide range of target-proteins. This implicitly enables the concentration of calcium to influence many downstream physiological responses, including muscle contraction, learning and depression. The antipsychotic drug trifluoperazine (TFP) is a known CaM inhibitor. By binding to various sites, TFP prevents CaM from associating to target-proteins. However, the molecular and state-dependent mechanisms behind CaM inhibition by drugs such as TFP are largely unknown. Here, we build a Markov state model (MSM) from adaptively sampled molecular dynamics simulations and reveal the structural and dynamical features behind the inhibitory mechanism of TFP-binding to the C-terminal domain of CaM. We specifically identify three major TFP binding-modes from the MSM macrostates, and distinguish their effect on CaM conformation by using a systematic analysis protocol based on biophysical descriptors and tools from machine learning. The results show that depending on the binding orientation, TFP effectively stabilizes features of the calcium-unbound CaM, either affecting the CaM hydrophobic binding pocket, the calcium binding sites or the secondary structure content in the bound domain. The conclusions drawn from this work may in the future serve to formulate a complete model of pharmacological modulation of CaM, which furthers our understanding of how these drugs affect signaling pathways as well as associated diseases.
Topics: Calmodulin; Trifluoperazine; Antipsychotic Agents; Calcium; Protein Binding; Binding Sites
PubMed: 36206305
DOI: 10.1371/journal.pcbi.1010583 -
Methylene blue as adjunctive therapy in septic shock: correct drug diluent derives optimal efficacy.Critical Care (London, England) Aug 2023
Topics: Humans; Methylene Blue; Shock, Septic; Dental Care; Patients
PubMed: 37644588
DOI: 10.1186/s13054-023-04615-2 -
Biotechnic & Histochemistry : Official... Nov 2024Romanowsky staining was an important methodological breakthrough in diagnostic hematology and cytopathology during the late 19 and early 20 centuries; it has facilitated... (Review)
Review
Romanowsky staining was an important methodological breakthrough in diagnostic hematology and cytopathology during the late 19 and early 20 centuries; it has facilitated for decades the work of biologists, hematologists and pathologists working with blood cells. Despite more than a century of studying Romanowsky staining, no systematic review has been published that explains the chemical processes that produce the "Romanowsky effect" or "Romanowsky-Giemsa effect" (RGE), i.e., a purple coloration arising from the interaction of an azure dye with eosin and not due merely to their simultaneous presence. Our review is an attempt to build a bridge between chemists and biomedical scientists and to summarize the available data on methylene blue (MB) demethylation as well as the related reduction and decomposition of MB to simpler compounds by both light and enzyme systems and microorganisms. To do this, we analyze modern data on the mechanisms of MB demethylation both in the presence of acids and bases and by disproportionation due to the action of light. We also offer an explanation for why the RGE occurs only when azure B, or to a lesser extent, azure A is present by applying experimental and calculated physicochemical parameters including dye-DNA binding constants and electron density distributions in the molecules of these ligands. Finally, we discuss modern techniques for obtaining new varieties of Romanowsky dyes by modifying previously known ones. We hope that our critical literature study will help scientists understand better the chemical and physicochemical processes and mechanisms of cell staining with such dyes.
Topics: Azure Stains; Staining and Labeling; Coloring Agents; Methylene Blue; Eosine Yellowish-(YS)
PubMed: 37929609
DOI: 10.1080/10520295.2023.2273860 -
Sensors (Basel, Switzerland) Nov 2023This paper describes the development of a simple voltammetric biosensor for the stereoselective discrimination of myo-inositol (myo-Ins) and D-chiro-inositol...
This paper describes the development of a simple voltammetric biosensor for the stereoselective discrimination of myo-inositol (myo-Ins) and D-chiro-inositol (D-chiro-Ins) by means of bovine serum albumin (BSA) adsorption onto a multi-walled carbon nanotube (MWCNT) graphite screen-printed electrode (MWCNT-GSPE), previously functionalized by the electropolymerization of methylene blue (MB). After a morphological characterization, the enantioselective biosensor platform was electrochemically characterized after each modification step by differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The results show that the binding affinity between myo-Ins and BSA was higher than that between D-chiro-Ins and BSA, confirming the different interactions exhibited by the novel BSA/MB/MWCNT/GSPE platform towards the two diastereoisomers. The biosensor showed a linear response towards both stereoisomers in the range of 2-100 μM, with LODs of 0.5 and 1 μM for myo-Ins and D-chiro-Ins, respectively. Moreover, a stereoselectivity coefficient α of 1.6 was found, with association constants of 0.90 and 0.79, for the two stereoisomers, respectively. Lastly, the proposed biosensor allowed for the determination of the stereoisomeric composition of myo-/D-chiro-Ins mixtures in commercial pharmaceutical preparations, and thus, it is expected to be successfully applied in the chiral analysis of pharmaceuticals and illicit drugs of forensic interest.
Topics: Inositol; Methylene Blue; Stereoisomerism
PubMed: 38005597
DOI: 10.3390/s23229211 -
Viruses Dec 2023Coronaviruses (CoVs) belong to the group of enveloped positive-sense single-strand RNA viruses and are causative agents of respiratory, gastro-intestinal, and central...
Coronaviruses (CoVs) belong to the group of enveloped positive-sense single-strand RNA viruses and are causative agents of respiratory, gastro-intestinal, and central nervous systems diseases in many host species, i.e., birds, mammals, and humans. Beta-CoVs revealed a great potential to cross the barrier between species by causing three epidemics/pandemics among humans in the 21st century. Considering the urgent need for powerful antiviral agents for decontamination, prevention, and treatment of BCoV infections, we turned our attention to the possibility of photodynamic inactivation with photosensitizers in combination with light irradiation. In the present study, we evaluated, for the first time, the antiviral activity of toluidine blue O (TBO) against Beta-coronavirus 1 (BCoV) in comparison to methylene blue (MB). First, we determined the in vitro cytotoxicity of MB and TBO on the Madin-Darby bovine kidney (MDBK) cell line with ISO10993-5/Annex C. Thereafter, BCoV was propagated in MDBK cells, and the virus titer was measured with digital droplet PCR, TCID assay and plaque assay. The antiviral activity of non-toxic concentrations of TBO was estimated using the direct inactivation approach. All effects were calculated in MAPLE 15 mathematical software by developing programs for non-linear modeling and response surface analysis. The median inhibitory concentration () of TBO after 72 h of incubation in MDBK cells was 0.85 µM. The antiviral activity of TBO after the direct inactivation of BCoV ( = 1) was significantly stronger than that of MB. The median effective concentration (EC) of TBO was 0.005 µM. The cytopathic effect decreased in a concentration-dependent manner, from 0.0025 to 0.01 µM, and disappeared fully at concentrations between 0.02 and 0.3 µM of TBO. The number of virus particles also decreased, depending on the concentration applied, as proven by ddPCR analysis. In conclusion, TBO exhibits significant potential for direct inactivation of BCoV in vitro, with a very high selectivity index, and should be subjected to further investigation, aiming at its application in veterinary and/or human medical practice.
Topics: Humans; Cattle; Animals; Coronavirus, Bovine; Photosensitizing Agents; Tolonium Chloride; Coronavirus; Coronavirus Infections; Methylene Blue; Pandemics; Antiviral Agents; Mammals
PubMed: 38257748
DOI: 10.3390/v16010048 -
Journal of Biomolecular Structure &... Jul 2023Theoretical analyses of two phenothiazine derivatives, 10-[3-(dimethylamino)-2-methylpropyl]phenothiazine-2-carbonitrile (CYM) and...
DFT and MD investigations of the biomolecules of phenothiazine derivatives: interactions with gold and water molecules and investigations in search of effective drug for SARS-CoV-2.
Theoretical analyses of two phenothiazine derivatives, 10-[3-(dimethylamino)-2-methylpropyl]phenothiazine-2-carbonitrile (CYM) and 2-[4-[3-(2-chlorophenothiazin-10-yl)propyl]piperazin-1-yl]ethanol (PAZ) are reported using density functional theory (DFT) and molecular dynamics (MD) simulations. Spectroscopic studies, different electronic and chemical parameters are predicted. Red and yellow in electrostatic potential plot is in rings and oxygen atom in PAZ and C≡N and rings in CYM are sensitive to nucleophilic attacks. The blue in hydrogen atoms refer to electrophilic attack in both PAZ and CYM. Stability of the protein-ligand complex formed with these derivatives and angiotensin-converting enzyme 2 (ACE2) was investigated using MD simulation. Radius of gyration of C-alpha atom of 6VW1 displayed the conformational convergence toward a compact structure leading to stable 6VW1-ligand complex which are also in agreement with root mean square fluctuation (RMSF) values. Localized area predicts reactive sites for Au and HO molecules interaction with these compounds for further practical applications. Charge density is localized on both molecules and also tries to move toward Au-Au dimer and water molecule and such they are expected to contribute to the sensing performance.Communicated by Ramaswamy H. Sarma.
Topics: Humans; SARS-CoV-2; Gold; Ligands; COVID-19; Antipsychotic Agents; Phenothiazines; Molecular Dynamics Simulation; Molecular Docking Simulation
PubMed: 35470781
DOI: 10.1080/07391102.2022.2068649 -
Advanced Healthcare Materials Oct 2023Photothermal therapy (PTT) is a promising approach to cancer treatment. Heptamethine cyanine (Cy7) is an attractive photothermal reagent because of its large molar...
Photothermal therapy (PTT) is a promising approach to cancer treatment. Heptamethine cyanine (Cy7) is an attractive photothermal reagent because of its large molar absorption coefficient, good biocompatibility, and absorption of near-infrared irradiation. However, the photothermal conversion efficiency (PCE) of Cy7 is limited without ingenious excitation-state regulation. In this study, the photothermal conversion ability of Cy7 is efficiently enhanced based on photo-induced electron transfer (PET)-triggered structural deformation. Three Cy7 derivatives, whose Cl is replaced by carbazole, phenoxazine, and phenothiazine at the meso-position (CZ-Cy7, PXZ-Cy7, and PTZ-Cy7), are presented as examples to demonstrate the regulation of the energy release of the excited states. Because the phenothiazine moiety exhibits an obvious PET-induced structural deformation in the excited state, which quenches the fluorescence and inhibits intersystem crossing of S →T , PTZ-Cy7 exhibits a PCE as high as 77.5%. As a control, only PET occurs in PXZ-Cy7, with a PCE of 43.5%. Furthermore, the PCE of CZ-Cy7 is only 13.0% because there is no PET process. Interestingly, PTZ-Cy7 self-assembles into homogeneous nanoparticles exhibiting passive tumor-targeting properties. This study provides a new strategy for excited-state regulation for photoacoustic imaging-guided PTT with high efficiency.
Topics: Humans; Electrons; Phototherapy; Nanoparticles; Neoplasms; Phenothiazines; Photoacoustic Techniques
PubMed: 37321560
DOI: 10.1002/adhm.202301091 -
Molecules (Basel, Switzerland) Feb 2023Antipsychotics have narrow therapeutic windows, and their monitoring in biological fluids is therefore important; consequently, stability in those fluids must be...
Antipsychotics have narrow therapeutic windows, and their monitoring in biological fluids is therefore important; consequently, stability in those fluids must be investigated during method development and validation. This work evaluates the stability of chlorpromazine, levomepromazine, cyamemazine, clozapine, haloperidol, and quetiapine in oral fluid (OF) samples, using the dried saliva spots (DSS) sampling approach and gas chromatography coupled to tandem mass spectrometry. Since many parameters can influence the stability of the target analytes, design of experiments was adopted to check the crucial factors that affect that stability in a multivariate fashion. The studied parameters were the presence of preservatives at different concentrations, temperature, light, and time. It was possible to observe that antipsychotic stability improved when OF samples in DSS were stored at 4 °C, with a low ascorbic acid concentration, and in the absence of light. With these conditions, chlorpromazine and quetiapine were stable for 14 days, clozapine and haloperidol were stable for 28 days, levomepromazine remained stable for 44 days, and cyamemazine was stable for the entire monitored period (146 days). This is the first study that evaluates the stability of these antipsychotics in OF samples after application to DSS cards.
Topics: Antipsychotic Agents; Clozapine; Quetiapine Fumarate; Haloperidol; Chlorpromazine; Methotrimeprazine; Gas Chromatography-Mass Spectrometry
PubMed: 36903275
DOI: 10.3390/molecules28052030 -
Molecular Neurobiology May 2021To demonstrate the role of the rate-limiting and ATP-dependent gluconeogenic enzyme phosphoenolpyruvate carboxykinase (PCK) in oxidative and lactic stress and the effect...
To demonstrate the role of the rate-limiting and ATP-dependent gluconeogenic enzyme phosphoenolpyruvate carboxykinase (PCK) in oxidative and lactic stress and the effect of phenothiazine on PCK after stroke, a total of 168 adult male Sprague Dawley rats (3 months old, 280-300 g) underwent 2-h intraluminal middle cerebral artery occlusion (MCAO) and reperfusion for 6, 24, 48 h, or 7 days. Phenothiazine (chlorpromazine and promethazine (C+P)) (8 mg/kg) and 3-mercaptopicolinic acid (3-MPA, a PCK inhibitor, 100 μM) were administered at reperfusion onset. The effects of phosphoenolpyruvate, 3-MPA, or PCK knockdown were studied in neuronal cultures subjected to oxygen/glucose deprivation. Reactive oxygen species, lactate, phosphoenolpyruvate (PEP; a gluconeogenic product), mRNA, and protein of total PCK, PCK-1, and PCK-2 increased after MCAO and oxygen-glucose deprivation (OGD). Oxaloacetate (a gluconeogenic substrate) decreased, while PEP and glucose were increased, suggesting reactive gluconeogenesis. These changes were attenuated by phenothiazine, 3-MPA, or PCK shRNA. PCK-1 and -2 existed primarily in neurons, while the effects of ischemic stroke on the PCK expression were seen predominately in astrocytes. Thus, phenothiazine reduced infarction and oxidative/lactic stress by inhibiting PCKs, leading to functional recovery.
Topics: Animals; Brain; Gluconeogenesis; Male; Neurons; Oxidative Stress; Phenothiazines; Phosphoenolpyruvate Carboxykinase (ATP); Picolinic Acids; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Stroke
PubMed: 33417227
DOI: 10.1007/s12035-020-02251-3 -
Water Research Dec 2023Two-dimensional materials are widely used in membrane separation, but the loose distribution and severe expansion between graphene oxide (GO) nanosheets limit its...
Two-dimensional materials are widely used in membrane separation, but the loose distribution and severe expansion between graphene oxide (GO) nanosheets limit its application. Here, we introduce a two-dimensional MOF material into the GO membrane to enhance its water permeance and separation performance. The MOF/GO composite membrane was prepared by vacuum filtration. The MOF and GO nanosheets were tightly stacked through the π-π effect, and the shortened transmission path and enhanced pore structure greatly improved the water permeance of the composite membrane. The MOF/GO membrane exhibited a high water permeance of 56.94 L m h bar. The rejection rates of methylene blue and was as methyl orange dyes were as high as 99.79% and 99.11%, respectively. At increased dye concentration, the rejection rate of methylene blue was still maintained greater than 99%. Dye rejection after 18 h of continuous operation remains above 90%. This work provides new ideas for improving membrane separation materials. The combination of two-dimensional heterogeneous materials can result in synergistic advantages for the development of composite membranes with high water permeance and high rejection rate.
Topics: Methylene Blue; Coloring Agents; Filtration; Water
PubMed: 37976627
DOI: 10.1016/j.watres.2023.120693