Two Fluorescent Probes for Recognition of Acetylcholinesterase: Design, Synthesis, and Comparative Evaluation.

In this study, two "on-off" probes (BF2-cur-Ben and BF2-cur-But) recognizing acetylcholinesterase (AChE) were designed and synthesized. The obtained probes can achieve recognition of AChE with good selectivity and pH-independence with a linear range of 0.5~7 U/mL and 0.5~25 U/mL respectively. BF2-cur-Ben has a lower limit of detection (LOD) (0.031 U/mL), higher enzyme affinity (Km = 16 ± 1.6 µM), and higher inhibitor sensitivity. A responsive mechanism of the probes for AChE was proposed based on HPLC and mass spectra (MS) experiments, as well as calculations. In molecular simulation, BF2-cur-Ben forms more hydrogen bonds (seven, while BF2-cur-But has only four) and thus has a more stable enzyme affinity, which is mirrored by the results of the comparison of Km values. These two probes could enable recognition of intracellular AChE and probe BF2-cur-Ben has superior cell membrane penetration due to its higher log p value. These probes can monitor the overexpression of AChE during apoptosis of lung cancer cells. The ability of BF2-cur-Ben to monitor AChE in vivo was confirmed by a zebrafish experiment.

Design, Synthesis, and Biological Evaluation of Novel Tetrahydroacridin Hybrids with Sulfur-Inserted Linkers as Potential Multitarget Agents for Alzheimer's Disease.

Alzheimer's disease (AD) is a complex neurodegenerative disease that can lead to the loss of cognitive function. The progression of AD is regulated by multiple signaling pathways and their associated targets. Therefore, multitarget strategies theoretically have greater potential for treating AD. In this work, a series of new hybrids were designed and synthesized by the hybridization of tacrine (4, AChE: IC50 = 0.223 µM) with pyrimidone compound 5 (GSK-3ß: IC50 = 3 µM) using the cysteamine or cystamine group as the connector. The biological evaluation results demonstrated that most of the compounds exhibited moderate to good inhibitory activities against acetylcholinesterase (AChE) and glycogen synthase kinase 3ß (GSK-3ß). The optimal compound 18a possessed potent dual AChE/GSK-3ß inhibition (AChE: IC50 = 0.047 ± 0.002 µM, GSK-3ß: IC50 = 0.930 ± 0.080 µM). Further molecular docking and enzymatic kinetic studies revealed that this compound could occupy both the catalytic anionic site and the peripheral anionic site of AChE. The results also showed a lack of toxicity to SH-SY5Y neuroblastoma cells at concentrations of up to 25 µM. Collectively, this work explored the structure-activity relationships of novel tetrahydroacridin hybrids with sulfur-inserted linkers, providing a reference for the further research and development of new multitarget anti-AD drugs.

Disentangling the formation, mechanism, and evolvement of the covalent methanesulfonyl fluoride acetylcholinesterase adduct: Insights into an aged-like inactive complex susceptible to reactivation by a combination of nucleophiles.

Chemical warfare nerve agents and pesticides, known as organophosphorus compounds inactivate cholinesterases (ChEs) by phosphorylating the serine hydroxyl group located at the active site of ChEs. Over the course of time, phosphorylation is followed by loss of an organophosphate-leaving group and the bond with ChEs becomes irreversible, a process known as aging. Differently, structurally related irreversible catalytic poisons bearing sulfur instead of phosphorus convert ChEs in its aged form only by covalently binding to the key catalytic serine. Kinetic and crystallographic studies of the interaction between Torpedo californica acetylcholinesterase (TcAChE) and a small organosulfonate, methanesulfonyl fluoride (MSF), indeed revealed irreversibly methylsulfonylated serine 200, to be isosteric with the bound aged sarin/soman analogues. The potent bulky reversible inhibitor 7-bis-tacrine (BTA) adopts, in the active site of the crystal structure of the MSF-enzyme adduct, a location and an orientation that closely resemble the one being found in the crystal structure of the BTA-enzyme complex. Remarkably, the presence of BTA accelerates the rate of methanesulfonylation by a factor of two. This unexpected result can be explained on the basis of two facts: i) the steric hindrance exerted by BTA to MSF in accessing the active site and ii) the acceleration of the MSF-enzyme adduct formation as a consequence of the lowering of the rotational and translational degrees of freedom in the proximity of the catalytic serine. It is well known that pralidoxime (2-Pyridine Aldoxime Methyl chloride, 2-PAM) alone or in the presence of the substrate acetylcholine cannot reactivate the active site serine of the TcAChE-MSF adduct. We show that the simultaneous presence of 2-PAM and the additional neutral oxime, 2-[(hydroxyimino)methyl]-l-methylimidazol (2-HAM), triggers the reactivation process of TcAChE within the hour timescale. Overall, our results pave the way toward the likely use of a cocktail of distinctive oximes as a promising recipe for an effective and fast reactivation of aged cholinesterases.

Direct detection of acetylcholinesterase by Fe(HCOO)2.6(OH)0.3. H2O nanosheets with oxidase-like activity on a smartphone platform.

Monitoring acetylcholinesterase (AChE) is crucial in clinical diagnosis and drug screening. Traditional methods for detecting AChE usually require the addition of intermediates like acetylthiocholine, which complicates the detection process and introduces interference risks. Herein, we develop a direct colorimetric assay based on alkaline iron formate nanosheets (Fe(HCOO)2.6(OH)0.3·H2O NSs, Fef NSs) for the detection of AChE without any intermediates. The as-prepared Fef NSs exhibit oxidase-like activity, catalyzing the generation of O2·-, 1O2 and ·OH, which leads to a color change from colorless to blue when exposed to 3,3',5,5'-tetramethylbenzidine. AChE directly inhibits the oxidase-like activity of Fef NSs, resulting in a hindered color reaction, enabling the detection of AChE. The biosensor has a linear detection range of 0.1-30 mU/mL, with a minimum detection limit of 0.0083 mU/mL (S/N = 3), representing a 100-fold improvement in detection sensitivity over the traditional Ellman's method. Satisfactory results were obtained when analyzing real AChE samples. Attractively, a method for the quantitative detection of AChE by a smartphone is established based on the Fef NSs. This method enables instant acquisition of AChE concentrations, achieving real-time visualized detection.

New amide and diterpene alkaloids with anticholinesterase activity from Delphinium cyphoplectrum roots.

BACKGROUND: The cholinergic hypothesis posits a robust correlation between the onset of Alzheimer's disease and a pronounced deficit in acetylcholine, a pivotal neurotransmitter crucial for the central cholinergic nervous system's function, pivotal for memory and learning. Diterpene alkaloids exhibit intricate and distinctive chemical structures that facilitate their passage through the blood-brain barrier. Moreover, their potent pharmacological attributes render them promising candidates for addressing central nervous system disorders. OBJECTIVES: This investigation aims to scrutinize the alkaloidal composition of Delphinium cyphoplectrum (Ranunculaceae) roots, further exploring their anticholinesterase inhibitory activity and mode of inhibition. METHOD: Innovative chromatography techniques were repetitively employed to purify the alkaloids. Acetylcholinesterase (AChE) inhibition assays were conducted using Ellman's tests. The mode of inhibition was meticulously characterized through Michaelis-Menten, and Lineweaver-Burk plots. Conducting molecular docking studies, we employed the AUTO DOCK 4.2 software package. RESULTS: Eight alkaloids were identified including five C19-diterpene alkaloids (6,14,16,18-tetramethoxy-1,7,8-trihydroxy-4-methylaconitane (1), 6,16,18-trimethoxy-1,7,8,14-tetrahydroxy-4-methylaconitane (2), 6,8,16,18-tetramethoxy-1,7,14-trihydroxy-4-methylaconitane (3), 6,14,16-trimethoxy-1,7,8,18-tetrahydroxy-4-methylaconitane (4), and 14-O-acetyl-8,16-dimethoxy-1,6,7,18-tetrahydroxy-4-methylaconitane (5)), an epoxy C18-diterpene alkaloid (6,8,16-trimethoxy-1,7,14-trihydroxy-3,4-epoxyaconitane (6)), a known (pyrrolidin-2-one (7) and an undescribed amide alkaloid (1-(2'-hydroxylethylamine)-3,5,5,-trimethyl-1,5-dihydro-2H-pyrrol-2-one (8). All diterpene alkaloids underwent assessment for acetylcholinesterase (AChE) inhibition assay and displayed noteworthy AChE activity, surpassing that of the reference drug (with IC50 values of 13.7, 21.8, 23.4, 28.2, 40.4, and 23.9 for compounds 1-6, respectively, in comparison to 98.4 for Rivastigmine). Analysis of Michaelis-Menten and Lineweaver-Burk plots represents an uncompetitive mode of inhibition for compound 1 on AChE. Notably, computational docking simulations indicated that all diterpene alkaloids were accommodated within the same enzymatic cleft as the reference ligand, and displaying superior free binding energy values (from - 10.32 to -8.59 Kcal.mol-1) in contrast to Rivastigmine (-6.31 Kcal.mol-1). CONCLUSION: The phytochemical analysis conducted on the roots of Delphinium cyphoplectrum yielded the identification of eight alkaloidal compounds including one C18-diterpene, five C19-diterpene, one pyrrolidine and one amide alkaloids. AChE inhibition assay and molecular simulations unveiled remarkable significant potency attributed to the C19-diterpene alkaloids by the order of 1 > 2 > 3,6 > 4 > 5. Presence of hydroxyl group on C-1, C-7, C-8, C-14, and C-18 increased the effect. The best in vitro activity was recorded for compound 1 able to bind to Asp72 in the narrow region of PAS, while interacting by pi-sigma with Phe330 at the hydrophobic region of the gorge involving the acyl and choline binding site. This observation underscores the substantial promise of this category of natural products in the realm of drug discovery for Alzheimer's Disease, offering a compelling avenue for further research and therapeutic development.

Environmental exposure to glyphosate does not inhibit human acetylcholinesterase and butyrylcholinesterase.

Glyphosate has remained the leading herbicide on the global market to date, despite the continuous debate between consumers, scientific community, and regulatory agencies over its carcinogenicity, genotoxicity, environmental persistence, and the role in the development of neurodegenerative disorders. Chemically, glyphosate belongs to a large family of organophosphorus pesticides, which exert a neurotoxic effect by inhibiting acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), enzymes of the cholinergic system essential for maintaining neurotransmission. Although research shows that glyphosate is a weak cholinesterase inhibitor in fish and mammals compared to other OP compounds, no conclusive data exist concerning the inhibition of human AChE and BChE. In our study we analysed its inhibitory potency on human AChE and BChE, by establishing its IC50 and reversible inhibition in terms of dissociation inhibition constants. Glyphosate concentration of 40 mmol/L caused near total inhibition of enzyme activity (approx. 10 % activity remaining). Inhibition dissociation constants (K i) of glyphosate-AChE and -BChE complexes were 28.4±2.7 mmol/L and 19.3±1.8 mmol/L, respectively. In conclusion, glyphosate shows a slight binding preference for BChE but exhibits inhibition only in a high concentration range. Our results are in line with studies reporting that its neurotoxic effect is not primarily linked to the cholinergic system.

Acetylcholine triggered enzymatic cascade reaction based on Fe7S8 nanoflakes catalysis for organophosphorus pesticides visual detection.

BACKGROUND: Organophosphorus pesticides (OPs) play important roles in the natural environment, agricultural fields, and biological prevention. The development of OPs detection has gradually become an effective strategy to avoid the dangers of pesticides abuse and solve the severe environmental and health problems in humans. Although conventional assays for OPs analysis such as the bulky instrument required analytical methods have been well-developed, it still remains the limitation of inconvenient, inefficient and lab-dependence analysis in real samples. Hence, there is an urgent demand to develop efficient detection methods for OPs analysis in real scenarios. RESULTS: Here, by virtue of the highly efficient catalytic performance in Fe7S8 nanoflakes (Fe7S8 NFs), we propose an OPs detection method that rationally integrated Fe7S8 NFs into the acetylcholine (ACh) triggered enzymatic cascade reaction (ATECR) for proceeding better detection performances. In this method, OPs serve as the enzyme inhibitors for inhibiting ATECR among ACh, acetylcholinesterase (AChE), and choline oxidase (CHO), then reduce the generation of H2O2 to suppress the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) that catalyzed by Fe7S8 NFs. Benefiting from the integration of Fe7S8 NFs and ATECR, it enables a sensitive detection for OPs (e.g. dimethoate). The proposed method has presented good linear ranges of OPs detection ranging from 0.1 to 10 µg mL-1. Compared to the other methods, the comparable limits of detection (LOD) of OPs are as low as 0.05 µg mL-1. SIGNIFICANCE: Furthermore, the proposed method has also achieved a favorable visual detection performance of revealing OPs analysis in real samples. The visual signals of OPs can be transformed into RGB values and gathered by using smartphones, indicating the great potential in simple, sensitive, instrument-free and on-site analysis of pesticide residues in environmental monitoring and biosecurity research.

Sequential Contrastive and Deep Learning Models to Identify Selective Butyrylcholinesterase Inhibitors.

Butyrylcholinesterase (BChE) is a target of interest in late-stage Alzheimer's Disease (AD) where selective BChE inhibitors (BIs) may offer symptomatic treatment without the harsh side effects of acetylcholinesterase (AChE) inhibitors. In this study, we explore multiple machine learning strategies to identify BIs in silico, optimizing for precision over all other metrics. We compare state-of-the-art supervised contrastive learning (CL) with deep learning (DL) and Random Forest (RF) machine learning, across single and sequential modeling configurations, to identify the best models for BChE selectivity. We used these models to virtually screen a vendor library of 5 million compounds for BIs and tested 20 of these compounds in vitro. Seven of the 20 compounds displayed selectivity for BChE over AChE, reflecting a hit rate of 35% for our model predictions, suggesting a highly efficient strategy for modeling selective inhibition.

Interactions between forsythoside E and two cholinesterases at the different conditions: fluorescence sections.

Forsythoside E is one secondary metabolite ofForsythia suspensa(Thunb.) Vahl. In the study, the interactions between forsythoside E and two types of cholinesterases, acetylcholinesterase and butyrylcholinesterase were investigated in the different conditions. Forsythoside E increased the fluorescence intensity of acetylcholinesterase but quenched the fluorescence of butyrylcholinesterase. Aß25-35used in the study may not form complexes with cholinesterases, and did not affect the interaction between forsythoside E and cholinesterases. The charged quaternary group of AsCh interacted with the 'anionic' subsite in acetylcholinesterase, which did not affect the interaction between forsythoside E and acetylcholinesterase. The enhancement rate of forsythoside E to acetylcholinesterase fluorescence from high to low was acid solution (pH 6.4), neutral solution (pH 7.4) and alkaline solution (pH 8.0), while the reduction rate of forsythoside E to butyrylcholinesterase fluorescence was in reverse order. Metal ions may interact with cholinesterases, and increased the effects of forsythoside E to cholinesterases fluorescence, in order that Fe3+was the highest, followed by Cu2+, and Mg2+. A forsythoside E-butyrylcholinesterase complex at stoichiometric ratio of 1:1 was spontaneously formed, and the static quenching was the main quenching mode in the process of forsythoside E binding with butyrylcholinesterase. TheKvalues of two complexes were pretty much the same, suggesting that the interaction between cholinesterases and forsythoside E was almost unaffected by acid-base environment and metal ions. Thennumbers of two cholinesterases approximately equaled to one, indicating that there was only one site on each cholinesterase applicable for forsythoside E to bind to.

Pnictogen bond-driven control of the molecular interaction between organophosphorus and acetylcholinesterase enzyme.

This study addresses a comprehensive assessment of the interaction between chemical warfare agents (CWA) and acetylcholinesterase (AChE) systems, focus on the intriguing pnictogen-bond interaction (PnB). Utilizing the crystallographic data from the Protein Data Bank pertaining to the AChE-CWA complex involving Sarin (GB), Cyclosarin (GF), 2-[fluoro(methyl)phosphoryl]oxy-1,1-dimethylcyclopentane (GP) and venomous agent X (VX) agents, the CWA is systematically displaced by increments of 0.1 Å along the PO bond axis, extending its distance by 4 Å from the original position. The AIM analysis was carried out and consistently revealed the presence of a significant interaction along the PO bond. Investigating the intrinsic nature of the PnB, the NBO and the EDA analysis unearthed the contribution of orbital factors to the overall energy of the system. Strikingly, this observation challenges the conventional σ-hole explanation commonly associated with such interactions. This finding adds a layer of complexity to understanding of PnB, encouraging further exploration into the underlying mechanisms governing these intriguing chemical phenomena.

Design, synthesis and biological evaluation of bakuchiol derivatives as multi-target agents for the treatment of Alzheimer's disease.

The concept of multi-target-directed ligands offers fresh perspectives for the creation of brand-new Alzheimer's disease medications. To explore their potential as multi-targeted anti-Alzheimer's drugs, eighteen new bakuchiol derivatives were designed, synthesized, and evaluated. The structures of the new compounds were elucidated by IR, NMR, and HRMS. Eighteen compounds were assayed for acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in vitro using Ellman's method. It was shown that most of the compounds inhibited AChE and BuChE to varying degrees, but the inhibitory effect on AChE was relatively strong, with fourteen compounds showing inhibition of >50% at the concentration of 200 µM. Among them, compound 3g (IC50 = 32.07 ± 2.00 µM) and compound 3n (IC50 = 34.78 ± 0.34 µM) showed potent AChE inhibitory activities. Molecular docking studies and molecular dynamics simulation showed that compound 3g interacts with key amino acids at the catalytically active site (CAS) and peripheral anionic site (PAS) of acetylcholinesterase and binds stably to acetylcholinesterase. On the other hand, compounds 3n and 3q significantly reduced the pro-inflammatory cytokines TNF-α and IL-6 released from LPS-induced RAW 264.7 macrophages. Compound 3n possessed both anti-acetylcholinesterase activity and anti-inflammatory properties. Therefore, an in-depth study of compound 3n is expected to be a multi-targeted anti-AD drug.

Lycopodium Alkaloids from Huperzia goebelii.

One new fawcettimine-type Lycopodium alkaloid, hupertimine F (1), together with five known (2-6) Lycopodium alkaloids were isolated from Huperzia goebelii. The structure of 1 was elucidated by 1D and 2D NMR spectra, HRESIMS, and X-ray diffraction. Structurally, 1 represents the fourth example of Lycopodium alkaloids characterized by a 5/5/5/5/6 pentacyclic ring system with a 1-aza-7-oxabicyclo[2.2.1]heptane moiety. These known compounds 2, 3, 5, and 6 were isolated from H. goebelii for the first time. Compounds 1-6 were evaluated for acetylcholinesterase, butyrylcholinesterase and monoamine oxidase B inhibitory activities in vitro.

Binding interactions and in silico ADME prediction of isoconessimine derivatives as potent acetylcholinesterase inhibitors.

In pursuit of new acetylcholinesterase (AChE) inhibitors for treating Alzheimer's disease (AD), a series of ten previously synthesized isoconessimine compounds (7a-7j) was in silico investigated for their binding interactions with AChE and pharmacokinetics based on absorption, distribution, metabolism, and excretion (ADME) properties using molecular docking, ONIOM (Our own N-layered Integrated molecular Orbital and molecular Mechanics) method and SwissADME tools. Docking experiments showed that all compounds bind within the active site gorge of AChE (PDB entry 1C2B), posing its aryloxy-substitutional ethyl group to catalytic site and conessine skeleton to peripheral anionic site. ONIOM interaction energy was used as an ONIOM score to improve docking score, and it ranked 7b as the most potent AChE inhibitor, in agreement with previous experiment. Residues, ASP74, TRP86, GLY122, GLU202, TRP286, GLU292, SER293, ILE294, TYR337, TYR341, and HIS447 were identified as important for the binding of the AChE-isoconessimine complex. The SwissADME investigation suggested that four compounds (7a, 7c, 7d and 7f) agree with the rules of drug-likeness. The steric and electronic effects on the aryloxy-substitutional ethyl group as important factors in the AChE inhibition were also discussed, which brings a better understanding of Alzheimer's disease drug development.

Smartphone-assisted colorimetric biosensor for the determination of organophosphorus pesticides on the peel of fruits.

Nowadays, the widespread use of organophosphorus pesticides (OPs) in agricultural production leads to varying degrees of residues in crops, which pose a potential threat to human health. Conventional methods used in national standard for the detection of OPs in fruits and vegetables require expensive instruments or cumbersome sample pretreatment steps for the analysis. To address these challenges, in this work, we took advantage of the peroxidase-like activity of PtCu3 alloy nanocrystals (NCs) for a colorimetric and smartphone assisted sensitive detection of OPs. With the assist of a smartphone, the concentration of OPs on the peel of fruits could be obtained by comparing the B/RG value (the brightness value of blue divided by those of red and green) of a test strip with a calibration curve. This work not only provides a facile and cost-effective method to detect pesticides but also makes a positive contribution to food safety warning.

A Multienzyme Reaction-Mediated Electrochemical Biosensor for Sensitive Detection of Organophosphorus Pesticides.

Ethephon (ETH), a commonly employed growth regulator, poses potential health risks due to its residue in fruits and vegetables, leading to both acute and subchronic toxicity. However, the detection accuracy of ETH is compromised by the color effects of the samples during the detection process. In this work, a multienzyme reaction-mediated electrochemical biosensor (MRMEC) was developed for the sensitive, rapid, and color-interference-resistant determination of ETH. Nanozymes Fe3O4@Au-Pt and graphene nanocomplexes (GN-Au NPs) were prepared as catalysts and signal amplifiers for MRMEC. Acetylcholinesterase (AChE), acetylcholine (ACh), and choline oxidase (CHOx) form a cascade enzyme reaction to produce H2O2 in an electrolytic cell. Fe3O4@Au-Pt has excellent peroxidase-like activity and can catalyze the oxidation of 3,3',5,5'-tetramethvlbenzidine (TMB) in the presence of H2O2, resulting in a decrease in the characteristic peak current of TMB. Based on the inhibitory effect of ETH on AChE, the differential pulse voltammetry (DPV) current signal of TMB was used to detect ETH, offering the limit of detection (LOD) of 2.01 nmol L-1. The MRMEC method effectively analyzed ETH levels in mangoes, showing satisfactory precision (coefficient of variations, 2.88-15.97%) and recovery rate (92.18-110.72%). This biosensor holds promise for detecting various organophosphorus pesticides in food samples.

Organophosphate Detoxification and Acetylcholinesterase Reactivation Triggered by Zeolitic Imidazolate Framework Structural Degradation.

Organophosphate (OP) toxicity is related to inhibition of acetylcholinesterase (AChE) activity, which plays a key role in the neurotransmission process. In this work, we report the ability of different zinc zeolitic imidazolate frameworks (ZIFs) to behave as potential antidotes against OP poisoning. The Zn-L coordination bond (L = purine, benzimidazole, imidazole, or 2-methylimidazole) is sensitive to the G-type nerve agent model compounds diisopropylfluorophosphate (DIFP) and diisopropylchlorophosphate, leading to P-X (X = F or Cl) bond breakdown into nontoxic diisopropylphosphate. P-X hydrolysis is accompanied by ZIF structural degradation (Zn-imidazolate bond hydrolysis), with the concomitant release of the imidazolate linkers and zinc ions representing up to 95% of ZIF particle dissolution. The delivered imidazolate nucleophilic attack on the OP@AChE adduct gives rise to the recovery of AChE enzymatic function. P-X bond breakdown, ZIF structural degradation, and AChE reactivation are dependent on imidazolate linker nucleophilicity, framework topology, and particle size. The best performance is obtained for 20 nm nanoparticles (NPs) of Zn(2-methylimidazolate)2 (sod ZIF-8) exhibiting a DIFP degradation half-life of 2.6 min and full recovery of AChE activity within 1 h. 20 nm sod ZIF-8 NPs are not neurotoxic, as proven by in vitro neuroblastoma cell culture viability tests.

Highly Sensitive and Rapid Screening Technique for the Detection of Organophosphate Pesticides and Copper Compounds Using Bifunctional Recombinant TrxA-PvCarE1.

Enabling the detection of organophosphate pesticide (OP) residues through enzyme inhibition-based technology is crucial for ensuring food safety and human health. However, the use of acetylcholinesterase, the primary target enzyme for OPs, isolated from animals in practical production poses challenges in terms of sensitivity and batch stability. To address this issue, we identified a highly sensitive and reproducible biorecognition element, TrxA-PvCarE1, derived from red kidney beans and successfully overexpressed it in Escherichia coli. The resulting recombinant TrxA-PvCarE1 exhibited remarkable sensitivity toward 10 OPs, surpassing that of commercial acetylcholinesterase. Additionally, this approach demonstrated the capability to simultaneously detect copper compounds with high sensitivity, expanding the range of pesticides detectable using the traditional enzyme inhibition method. Spiking recovery tests conducted on cowpea and carrot samples verified the suitability of the TrxA-PvCarE1-based technique for real-life sample analysis. In summary, this study highlights a promising comprehensive candidate for the rapid detection of pesticide residues.

New Azo Derivative of ß-Diketones and Its Cu(II), Co(II) Complexes: Synthesis, Theoretical Study and Biological Activity.

The paper is focused on biological activity and theoretical study of the structure and properties of a new azo derivative of ß-diketones and its complexes with some metals. The aim of our work was to study the structure and properties of the newly synthesized compound as well as to theoretically determine the possibility of complex formation with the Cu(II) or Co(II) ions. A compound with the same substituents R1=R2=CH3 was chosen for the study. A synthesized azo compound based on 4-amino antipyrine and its complexes with Cu(II), Co(II) in solution and solid phase is reported. The structures of these compounds have been testified by X-ray, IR and  NMR spectroscopy. The combined experimental and theoretical approach was used. To study the structure and properties of the synthesized compound, as well as its possible complex formation with the Cu(II), quantum-chemical calculations were carried out the 6-31G basis set and the electron density functional theory (DFT) method. These 3-(1-phenyl-2,3-dimethyl-pyrazolone-5) azopentadione-2,4 (PDPA) with Cu(II) and Co(II) complexes had effective inhibition against butyrylcholinesterase and acetylcholinesterase. IC50 values were found as 19.03, 3.64 µM for AChE and 28.47, 8.01 µM for BChE, respectively. Cholinesterase inhibitors work to slow down the acetylcholine's deterioration.

Iontronic Photoelectrochemical Biorecognition Probing.

Herein, the first iontronic photoelectrochemical (PEC) biorecognition probing is devised by rational engineering of a dual-functional bioconjugate, i.e., a light-sensitive intercalated structural DNA, as a smart gating module confined within a nanotip, which could respond to both the incident light and biotargets of interest. Light stimulation of the bioconjugate could intensify the negative charge at the nano-orifice to sustain enhanced ionic current. The presence of proteins (e.g., acetylcholinesterase, AChE) or nucleic acids (e.g., microRNA (miR)-10b) could lead to bioconjugate release with altered ionic signaling. The practical applicability of the methodology is confirmed by AChE detection in human serum and miR-10b detection in single cells.

A single post-exposure oxime RS194B treatment rapidly reactivates acetylcholinesterase and reverses acute symptoms in macaques exposed to diethylphosphorothioate parathion and chlorpyrifos insecticides.

Millions of individuals globally suffer from inadvertent, occupational or self-harm exposures from organophosphate (OP) insecticides, significantly impacting human health. Similar to nerve agents, insecticides are neurotoxins that target and inhibit acetylcholinesterase (AChE) in central and peripheral synapses in the cholinergic nervous system. Post-exposure therapeutic countermeasures generally include administration of atropine with an oxime to reactivate the OP-inhibited AChE. However, animal model studies and recent clinical trials using insecticide-poisoned individuals have shown minimal clinical benefits of the currently approved oximes and their efficacy as antidotes has been debated. Currently used oximes either reactivate poorly, do not readily cross the blood-brain barrier (BBB), or are rapidly cleared from the circulation and must be repeatedly administered. Zwitterionic oximes of unbranched and simplified structure, for example RS194B, have been developed that efficiently cross the BBB resulting in reactivation of OP-inhibited AChE and dramatic reversal of severe clinical symptoms in mice and macaques exposed to OP insecticides or nerve agents. Thus, a single IM injection of RS194B has been shown to rapidly restore blood AChE and butyrylcholinesterase (BChE) activity, reverse cholinergic symptoms, and prevent death in macaques following lethal inhaled sarin and paraoxon exposure. The present macaque studies extend these findings and assess the ability of post-exposure RS194B treatment to counteract oral poisoning by highly toxic diethylphosphorothioate insecticides such as parathion and chlorpyrifos. These OPs require conversion by P450 in the liver of the inactive thions to the active toxic oxon forms, and once again demonstrated RS194B efficacy to reactivate and alleviate clinical symptoms within 60 mins of a single IM administration. Furthermore, when delivered orally, the Tmax of RS194B at 1-2 h was in the same range as those administered IM but were maintained in the circulation for longer periods greatly facilitating the use of RS194B as a non-invasive treatment, especially in isolated rural settings.