Dissociation Constant Research Articles

Preparation, characterization, and ex vivo evaluation of isoxanthohumol nanosuspension

This study assessed the equilibrium solubility, oil–water distribution coefficient, and dissociation constant of Isoxanthohumol (IXN), and formulated IXN nanoparticles (IXN-Nps) using a micro media grinding method. The research characterized the particle size, polydispersity index, zeta potential, morphology, and structure of the nanoparticles, and evaluated the optimal cryoprotectant. Additionally, the study examined the toxicity and in vitro and in vivo release of IXN on HT-29 cells. IXN is classified as a Biopharmaceutical Classification System (BCS) II class drug with weak acidity. The average particle size of IXN-Nps is 249.500 nm, with a polydispersity index (PDI) of 0.149 and a zeta potential of −25.210 mV. The research identified 5 % mannitol as the optimal cryoprotectant. Compared to IXN, the half-maximal inhibitory concentration of IXN-Nps decreased to one-third, demonstrating a significant inhibitory effect on HT-29 colon cancer cells. The in vitro cumulative release rate of IXN-Nps within 24 h was 3.5 times higher than that of the IXN solution. In vivo pharmacokinetic results revealed that the oral bioavailability of IXN-Nps increased significantly by 2.8 times compared to the IXN solution. The correlation coefficient (r = 0.9227) exceeded the critical value for significance at the 0.01 (r = 0.834) level, indicating a strong correlation between in vivo and in vitro results. Consequently, the nanosuspension overcame the low solubility limitation of IXN and proved to be an effective method for enhancing the oral bioavailability of IXN

Design, spectral technique, anti-diabetic, anti-inflammatory, antioxidant, and molecular docking investigations of acridine derivatives

A novel acridine derivative was synthesised by conventional method. Every synthesised molecule was analysed by IR, 1H, 13C NMR and mass spectral techniques. Biological studies like anti-inflammatory and anti-oxidant activities with DPPH radical scavenging activity, anti-diabetic properties, and molecular docking were examined. The anti-diabetic properties of acridine derivatives indicate that compounds 2 and 7 exhibit greater activity compared to the typical acarbose one, with IC50 values of 26 and 25, respectively. According to in-vitro investigations on anti-inflammatory effect, compounds 4 and 6 have larger inhibition percentages than the other compounds. The oxidoreductase tuberculosis protein is tightly docked with the synthesised moieties. Compound 7 exhibits the highest inhibition constant of 608.73 μM. The remarkable anti-inflammatory and antioxidant properties, together with its synthesis and characterization, highlight its potential as a viable candidate for more biomedical research and therapeutic development

New Bis 4-Bromobenzene Sulphonate Compound: Synthesis, Characterizaton, DFT study, Antibacterial and Leishmanicidal activity

The new bis 4-bromobenzene sulphonate compound called as ((1E,1'E)-(1,4-phenylenebis(azanylylidene))bis(methanylylidene))bis(4,1-phenylene) bis(4-bromobenzenesulfonate) (I) was synthesized. Fourier transform infrared (FTIR), proton and carbon-13 nuclear magnetic resonance (1H- and 13C-NMR) methods were used to confirm the molecular structure. All calculations were performed at DFT/B3LYP/6-311G(d,p) level. IR and NMR spectral data were compared with experimental ones and the details of molecular structure were investigated. The antimicrobial activity of the synthesized compound (I) was determined by Alamar blue microdilution method against seven different established standard bacteria and one parasite isolate. The compound I exhibited antibacterial activity at different concentrations. Compound I was found to have antimicrobial activity on all bacterial species and L. infantum parasite, albeit at different concentrations. Compound I has the most effective antibacterial activity on S. flexneri and the least effect on S. aureus and E. cloacea bacteria. In order for the synthesized compound to be used as a drug candidate, in vivo control studies in a series of experimental animal models and whether it has toxic effects on human cells should be tested. In silico analysis was conducted on four different proteins using the synthesized compound I to investigate the essential interactions responsible for its antibacterial activity. The docking results of compound I supported its antibacterial activity, revealing high inhibition constants.

Kunitz-type trypsin inhibitor from durian (Durio zibethinus) employs a distinct loop for trypsin inhibition.

Kunitz-type trypsin inhibitors are ubiquitous in plants. They have been proposed to be a part of a defense mechanism against herbivores. Trypsin inhibitors also have potential applications in the biotechnology industry, such as in mammalian cell culture. We discovered that durian (Durio zibethinus) seed contains Kunitz-type trypsin inhibitors as identified by N-terminal sequencing and mass spectrometry. Eleven new trypsin inhibitors were cloned. The D. zibethinus trypsin inhibitors (DzTIs) that are likely expressed in the seed were produced as recombinant proteins and tested for trypsin inhibitory activity. Their inhibitory activity and crystal structures are similar to the soybean trypsin inhibitor. Surprisingly, a crystal structure of the complex between DzTI-4, the DzTI with the lowest inhibitory constant, and bovine trypsin revealed that DzTI-4 utilized a novel tryptophan-containing β1-β2 loop to bind trypsin. Site-direct mutagenesis confirmed the inhibitory role of this loop. DzTI-4 was not toxic to the HEK293 cells and could be used in place of the soybean trypsin inhibitor for culturing the cells under serum-free conditions. DzTI-4 was not toxic to mealworms. However, a mixture of DzTIs extracted from durian seed prevented weight gain in mealworms, suggesting that multiple trypsin inhibitors are required to achieve the antinutritional effect. This study highlights the biochemical diversity of the inhibitory mechanism of Kunitz-type trypsin inhibitors and provides clues for further application of these inhibitors.

An OPRM1-SNAP-tag/CMC method to directly identify drug components in sewage.

The scourge of drug addiction and abuse poses a significant challenge to society. Opioid drugs acting on μ-opioid receptor (OPRM1) make it one of the pivotal targets for drug addiction. In the past decade, sewage analysis has become a prevalent method of drug monitoring. However, traditional methods of detecting drugs in sewage are cumbersome, and rapid detection methods are relatively lacking. To address this, an innovative OPRM1-SNAP-tag/CMC method to directly identify drug components in sewage was established. Cell membrane chromatography (CMC) is an affinity chromatography technique which effectively detects receptor affinity substances. Cells constructed with high expression of specific receptor could be used to screen for compounds acting on the receptor. CMC based on OPRM1 provides a potentially convenient and effective tool for the detection of targeted drug components in sewage. In this study, the selectivity, reproducibility, column lifetime, and carryover of the CMC column had been assessed. Initially, we eluted the collected domestic sewage with methanol and acetonitrile, and the retention peaks were observed on the CMC system. Subsequently, without any preliminary sample preparation, we directly injected filtered samples of suspicious sewage into the OPRM1-SNAP-tag/CMC system, where we observed retention peaks as well. The retained components were further identified as morphine by using UPLC-MS/MS. In conclusion, the OPRM1-SNAP-tag/CMC method stands out as a reliable and robust model for the detection of drug components in sewage. It provides a valuable analytical tool for frontline drug control efforts, enhancing our capacity to monitor and mitigate the impact of drug abuse on society.

Targeting histidinol-phosphate aminotransferase in Acinetobacter baumannii with salvianolic acid B: A structure-based approach to novel antibacterial strategies

Undoubtedly, Acinetobacter baumannii is a major ESKAPE pathogen that poses a significant threat to public health, causing severe nosocomial infections with high mortality rates in healthcare settings. Due to the rapid development of antibiotic resistance, only a limited number of antibiotics remain effective against infections caused by multidrug-resistant (MDR) Acinetobacter baumannii. The discovery of new class of antibiotic molecules still lags behind the rate of growing worldwide burden of antimicrobial resistance (AMR). To expedite the discovery of new therapeutic molecules, we have focused on HisC from A. baumannii (AbHisC), a crucial enzyme involved in the seventh step of histidine biosynthesis. This pathway is absent in humans. We have employed the advanced computational techniques to target this promising drug target. AbHisC was cloned, overexpressed, and purified. Three distinct sets of libraries containing ∼60,000 natural compounds from ZINC database were screened against AbHisC using Schrödinger's glide module software. Based on the docking score and glide energy, top 25 hits were further subjected to induced fit (IF) docking. Top four out of the twenty five compounds from IF docking were subjected to 100ns molecular dynamics simulations, and it was observed that salvianolic acid B (SA-B) (a naturally occurring compound) complex with AbHisC, was found to be extremely stable. The glide energy and docking score of SA-B were −88.59 kcal/mol and −10.4 kcal/mol. SA-B was also found to quench the intrinsic fluorescence of tyrosine indicating its binding to the target. The dissociation constant calculated using Surface Plasmon Resonance was found to be 3.4x10−9 M. Based on these results we can conclude that SA-B can serve as the potential inhibitor of AbHisC that can further form the basis of structure based drug design against this deadly pathogen.

Aptamer-Based Detection of Foot-and-Mouth Disease Virus Using Single-Stranded DNA Probe.

Foot-and-mouth disease (FMD) is known for its highly contagious properties among cloven-hoofed animals resulting in significant morbidity rates. Incursions of this disease have caused significant losses in affected countries in Southeast Asia and Africa, even within EU countries which resulted in significant financial losses.This study is aimed at addressing existing limitations by creating a diagnostic method using aptamer-based assay. Three DNA aptamers were engineered to target the VP2 region of the FMD viral capsid protein. Since VP2 demonstrates a highly conserved amino acid sequence across serotypes, the specifically designed aptamers can detect different serotypes of the virus. Aptamers were evaluated against VP2 capsid protein, which was synthesized based on sequences from serotypes A, O, and Asia 1 of the FMD virus. After the recombinant VP2 capsid protein was developed, expressed, and refined, it was applied using enzyme-linked aptamer sorbent assay (ELASA) to determine aptamers' binding capability. A similar test was further conducted with purified FMD virus from serotype A and serotype O. The ELASA results displayed a notable sensitivity in identifying the FMDV. Under optimized conditions, the aptamers have LOD as low as 0.11ng/mL with LOQ as low as 0.34ng/mL. The binding strength analyzed using the equilibrium dissociation constant (Kd) showed strong binding affinity at 3.092 ± 0.05nM. Based on these findings, the method shows significant potential with high sensitivity and specificity for FMD virus detection assay.

Assessing the effects of 5-HT2A and 5-HT5A receptor antagonists on DOI-induced head-twitch response in male rats using marker-less deep learning algorithms.

Serotonergic psychedelics, which display a high affinity and specificity for 5-HT2A receptors like 2,5-dimethoxy-4-iodoamphetamine (DOI), reliably induce a head-twitch response in rodents characterized by paroxysmal, high-frequency head rotations. Traditionally, this behavior is manually counted by a trained observer. Although automation could simplify and facilitate data collection, current techniques require the surgical implantation of magnetic markers into the rodent's skull or ear. This study aimed to assess the feasibility of a marker-less workflow for detecting head-twitch responses using deep learning algorithms. High-speed videos were analyzed using the DeepLabCut neural network to track head movements, and the Simple Behavioral Analysis (SimBA) toolkit was employed to build models identifying specific head-twitch responses. In studying DOI (0.3125-2.5mg/kg) effects, the deep learning algorithm workflow demonstrated a significant correlation with human observations. As expected, the preferential 5-HT2A receptor antagonist ketanserin (0.625mg/kg) attenuated DOI (1.25mg/kg)-induced head-twitch responses. In contrast, the 5-HT5A receptor antagonists SB 699,551 (3 and 10mg/kg), and ASP 5736 (0.01 and 0.03mg/kg) failed to do so. Previous drug discrimination studies demonstrated that the 5-HT5A receptor antagonists attenuated the interoceptive cue of a potent hallucinogen LSD, suggesting their anti-hallucinatory effects. Nonetheless, the present results were not surprising and support the head-twitch response as selective for 5-HT2A and not 5-HT5A receptor activation. We conclude that the DeepLabCut and SimBA toolkits offer a high level of objectivity and can accurately and efficiently identify compounds that induce or inhibit head-twitch responses, making them valuable tools for high-throughput research.

Comparison of Orthogonal Determination Methods of Acid/Base Constants with Meta-Analysis

The accurate determination of acid/base constants (proton dissociation constants—pKa, or equivalently protonation constants—logK) is essential for the physicochemical characterization of new molecules, especially in drug design and development, as these parameters thoroughly influence the pharmacokinetics and pharmacodynamics of drug action. While pH/potentiometric titration remains the gold standard method for determining acid/base constants, spectroscopic techniques—particularly nuclear magnetic resonance spectroscopy (as NMR/pH titrations)—have emerged as powerful alternatives for specific challenges in analytical chemistry, providing also information on the structure and site of protonation. In this study, we performed a comprehensive meta-analysis of protonation constants reported in the literature, measured using both potentiometry and NMR titrations. Our analysis compiled the available literature data and assessed the agreement between the two methods, taking into consideration various experimental conditions, such as temperature and ionic strength. The results provide insights into the reliability and applicability of NMR titrations compared with potentiometry, offering guidance for selecting appropriate methodologies in drug design.

Therapeutic Monoclonal Antibody─Antidrug Antibody Affinity Constant Determination Using Capillary Electrophoresis-Tandem Mass Spectrometry.

Monoclonal antibody (mAbs) therapeutics cannot evade the occurrence of adverse effects. Thus, mAbs are commonly triggering immune responses corresponding to the expression of antidrug antibodies. Antidrug antibodies can neutralize mAbs, leading to their inhibition and hasten clearance, which dramatically hampers their therapeutic effects. Therefore, studies concerning the affinity between a mAbs and the corresponding antidrug antibody are demonstrating a growing interest to further understand the outcome of biotherapeutics after administration. We describe a novel analytical approach for the determination of the dissociation constant (Kd) between a mAb and an antidrug antibody using capillary electrophoresis coupled to mass spectrometry (CE-MS/MS). The CE-MS/MS method employs a competitive assay, followed by the quantification of the residual amount of the active mAbs. The methodology allowed for the measurement of Kd using serum samples without the implementation of immobilization to achieve protein-protein interaction. This characteristic enabled us to generate the interaction in conditions reflecting the physiological environment. A mathematical treatment was developed to calculate Kd from MS/MS data, taking into account the stoichiometry of the mAbs/antidrug antibody complex and the bivalent properties of the two immunoglobulins. Prior to CE-MS/MS analysis, the interaction of the two proteins was studied by using mass photometry (MP) to determine equilibrium conditions and complexation stoichiometry. CE-MS/MS was used to investigate the interaction between infliximab and a neutralizing anti-infliximab antibody. Results allowed to measure a Kd of 14.4 ± 2.9 nM. MS instrumentation sensitivity and specificity showed to be relevant to achieve accurate and robust Kd measurements for strong interactions in the nanomolar range.

Unraveling GPCRs Allosteric Modulation. Cannabinoid 1 Receptor as a Case Study.

G-protein-coupled receptors (GPCRs) constitute one of the most prominent families of integral membrane receptor proteins that mediate most transmembrane signaling processes. Malfunction of these signal transduction processes is one of the underlying causes of many human pathologies (Parkinson's, Huntington's, heart diseases, etc), provoking that GPCRs are the largest family of druggable proteins. However, these receptors have been targeted traditionally by orthosteric ligands, which usually causes side effects due to the simultaneous targeting of homologous receptor subtypes. Allosteric modulation offers a promising alternative approach to circumvent this problematic and, thus, comprehending its details is a most important task. Here we use the Cannabinoid type-1 receptor (CB1R) in trying to shed light on this issue, focusing on positive allosteric modulation. This is done by using the protein-dipole Langevin-dipole (PDLD) within the linear response approximation (LRA) framework (PDLD/S-2000) along with our coarse-grained (CG) model of membrane proteins to evaluate the dissociation constants (KBs) and cooperativity factors (αs) for a diverse series of CB1R positive allosteric modulators belonging to the 2-phenylindole structural class, considering CP55940 as an agonist. The agreement with the experimental data evinces that significantly populated allosteric modulator:CB1R and allosteric modulator:CP55940:CB1R complexes have been identified and characterized successfully. Analyzing them, it has been determined that CB1R positive allosteric modulation lies in an outwards displacement of transmembrane α helix (TM) 4 extracellular end and in the regulation of the range of motion of a compound TM7 movement for binary and ternary complexes, respectively. In this respect, we achieved a better comprehension of the molecular architecture of CB1R positive allosteric site, identifying Lys1923.28 and Gly1943.30 as key residues regarding electrostatic interactions inside this cavity, and to rationalize (at both structural and molecular level) the exhibited stereoselectivity in relation to positive allosteric modulation activity by considered CB1R allosteric modulators. Additionally, putative/postulated allosteric binding sites have been screened successfully, identifying the real CB1R positive allosteric site, and most structure-activity relationship (SAR) studies of CB1R 2-phenylindole allosteric modulators have been rationalized. All these findings point out towards the predictive value of the methodology used in the current work, which can be applied to other biophysical systems of interest. The results presented in this study contribute significantly to understand GPCRs allosteric modulation and, hopefully, will encourage a more thorough exploration of the topic.

Transcriptomic, mutational and structural bioinformatics approaches to explore the therapeutic role of FAP in predominant cancer types

Fibroblast activating protein (FAP) is a cell surface marker of cancer-associated fibroblasts with a distinct pro-tumorigenic role. The present study analyzed the pan-cancer expression; and clinical and mutational profiles of the FAP coding gene. Molecular dynamics simulation (MDS) deciphered the backbone dynamics and energetics of FAP. Virtual screening and subsequent pharmacokinetic-profiling (PK) filtered lead molecules, which were subjected to molecular docking. MDS projected a stable trajectory for the protein, as dynamics evidenced by low residue-level fluctuations, stable backbone dynamics, and energetics. Around five stabilization and deleterious mutations in the catalytic domain were identified. The low binding energy (BE) profiles from molecular docking studies screened the top five lead molecules for site-specific intermolecular interaction studies. Lead-16 (ZINC000245289699) exhibited a significant BE and inhibition constant of −6.87 kcal/mol and 12.27 μM, respectively, across FAP and its mutants. Interestingly, the docked complexes of Lead-16 interacted with the catalytic triad residues (S624, D702, and H734). The docked complexes of Lead-16 with FAP showed lower average root-mean-square fluctuations compared to the unbound protein, suggesting a stable ligand–protein complex. The tumor-specific expression and its critical overall survival suggest the inhibitors of FAP for potential cancer therapeutic intervention and hindering tumor microenvironment-driven cancer progression.

Chemical extension and glycodendrimer formation of the matriglycan decasaccharide, -(3Xylα1-3GlcAβ1)5- and its affinity for laminin

Muscle tissue is stabilized by the strong interaction between laminin and matriglycan. Matriglycan is a polysaccharide composed of the repeating disaccharide, -3Xylα1-3GlcAβ1-, and is a pivotal part of the core M3 O-mannosyl glycan. Patients with muscular dystrophy cannot synthesize matriglycan or the core M3 O-mannosyl glycan due to a defect in or the lack of glycosyltransferases owing to glycan synthesis. Therefore, a supply of matriglycan may be a powerful tool for reconstructing muscle tissue in these patients. We herein report the synthesis of a matriglycan-repeating decasaccharide and a dendrimer comprising three branches of the decasaccharide. The glycan was regio- and stereoselectively synthesized by the stepwise addition of the corresponding disaccharide unit. The immobilized decasaccharide and glycodendrimer bound to laminin-G-like domains 4 and 5 of laminin-α2. The dissociation constants of the decasaccharide and dendrimer obtained from bio-layer interferometry were estimated to be 4.4 × 10−8 M and 6.8 × 10−8 M, respectively, showing higher affinity than those of a matriglycan-repeating hexasaccharide (1.6 × 10−7 M) and the dendrimer (1.8 × 10−7 M).

Affinity-tuned mesothelin CAR T cells demonstrate enhanced targeting specificity and reduced off-tumor toxicity.

The application of chimeric antigen receptor (CAR) T cell therapy in solid tumors is hindered by life-threatening toxicities resulting from on-target, off-tumor killing of nonmalignant cells that express low levels of the target antigen. Mesothelin (MSLN) has been identified as a target antigen for CAR T cell treatment of mesothelioma, lung, ovarian, and other cancers because of its high expression on tumor cells and limited expression on mesothelial cells. However, fatal off-tumor toxicity of high-affinity MSLN-targeting CAR T cells has been reported in multiple clinical trials. In this study, we constructed CARs using mutant variants of a single-domain nanobody that bind both human and mouse MSLN with a wide range of affinities and examined tumor responses and their toxicities from on-target, off-tumor interactions in mouse models. CAR T cells with low nanomolar affinity (equilibrium dissociation constant, KD) exhibited profound systemic expansion with no apparent infiltration into the tumor. With a gradual reduction of CAR affinity toward the micromolar KD, the expansion of CAR T cells became more restricted to tumors. Our preclinical studies demonstrated that high-affinity MSLN CARs were associated with fatal on-target, off-tumor toxicity and that affinity-tuned CARs rendered T cells more selective for MSLN-high tumors.

A Biolayer Interferometry-Based SARS-COV-2 Mpro-Targeted Active Ingredients Recognition System: Construction and Application in Ligand Screening From Herbal Medicines.

Drug discovery research targeting SARS-CoV-2 and other emerging pathogens remains critically important. Active compounds derived from plants frequently serve as lead compounds for further drug discovery; however, numerous unrelated chemical constituents in crude extracts may obscure the effective ingredients in LC-MS analysis. The aim of this study is to construct a biolayer interferometry (BLI)-based system for recognizing active ingredients that inhibit the main protease (Mpro) of SARS-CoV-2 and to identify the active chemical components binding to Mpro from herbal medicines. We developed a novel FRET fluorogenic probe by linking the amino acid sequences of the fluorescent proteins Lssmorange and mKate2 (Ls-mK). The interaction between traditional Chinese medicine and Mpro was analyzed using BLI. Ultrahigh performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) was employed to analyze the composition of herbal medicines. Fluorescence detection and spectroscopy confirmed the successful construction of an Mpro inhibitor screening system. Lanqin Oral Liquid (LQL) and Gardeniae fructus exhibited strong inhibitory effects on Mpro. Ten compounds were identified from G. fructus extracts; among them, deacetyl asperulosidic acid methyl ester (DAAME) and Gardoside were found to strongly bind to Mpro, with dissociation constants (KD) of 3.41 μM and 801 nM, respectively. The half-maximal inhibitory concentrations (IC50) of DAAME and Gardoside for Mpro were 27.46 and 13.7 μM, respectively. This study established a functional Mpro inhibitor screening system. Among the 10 components identified from G. fructus that bind to Mpro, DAAME and Gardoside displayed strong binding and inhibitory activity, indicating their potential as lead compounds for inhibiting SARS-CoV-2 viral replication.

Preclinical characterization of the Omicron XBB.1.5-adapted BNT162b2 COVID-19 vaccine

As SARS-CoV-2 evolves, increasing in potential for greater transmissibility and immune escape, updated vaccines are needed to boost adaptive immunity to protect against COVID-19 caused by circulating strains. Here, we report features of the monovalent Omicron XBB.1.5-adapted BNT162b2 vaccine, which contains XBB.1.5-specific sequence changes, relative to the original BNT162b2 backbone, in the encoded prefusion-stabilized SARS-CoV-2 spike protein (S(P2)). Biophysical characterization of Omicron XBB.1.5 S(P2) demonstrated that it maintains a prefusion conformation and adopts a flexible, predominantly open, state, with high affinity for the human ACE-2 receptor. When administered as a 4th dose in BNT162b2-experienced mice, the monovalent Omicron XBB.1.5 vaccine elicited substantially higher serum neutralizing titers against pseudotyped viruses of Omicron XBB.1.5, XBB.1.16, XBB.1.16.1, XBB.2.3, EG.5.1 and HV.1 sublineages and phylogenetically distant BA.2.86 lineage than the bivalent Wild Type + Omicron BA.4/5 vaccine. Similar trends were observed against Omicron XBB sublineage pseudoviruses when the vaccine was administered as a 2-dose series in naive mice. Strong S-specific Th1 CD4+ and IFNγ+ CD8+ T cell responses were also observed. These findings, together with real world performance of the XBB.1.5-adapted vaccine, suggest that preclinical data for the monovalent Omicron XBB.1.5-adapted BNT162b2 was predictive of protective immunity against dominant SARS-CoV-2 strains.

Glia-related Acute Effects of Risperidone and Haloperidol in Hippocampal Slices and Astrocyte Cultures from Adult Wistar Rats: A Focus on Inflammatory and Trophic Factor Release.

Antipsychotics are drugs commonly prescribed to treat a variety of psychiatric conditions. They are classified as typical and atypical, depending on their affinity for dopaminergic and serotonergic receptors. Although neurons have been assumed to be the major mediators of the antipsychotic pharmacological effects, glia, particularly astrocytes, have emerged as important cellular targets for these drugs. In the present study, we investigated the effects of acute treatments with the antipsychotics risperidone and haloperidol of hippocampal slices and astrocyte cultures, focusing on neuron-glia communication and how antipsychotics act in astrocytes. For this, we obtained hippocampal slices and primary astrocyte cultures from 30-day-old Wistar rats and incubated them with risperidone or haloperidol (1 and 10μM) for 30min and 24h, respectively. We evaluated metabolic and enzymatic activities, the glutathione level, the release of inflammatory and trophic factors, as well as the gene expression of signaling proteins. Haloperidol increased glucose metabolism; however, neither of the tested antipsychotics altered the glutathione content or glutamine synthetase and Na+K+-ATPase activities. Haloperidol induced a pro-inflammatory response and risperidone promoted an anti-inflammatory response, while both antipsychotics seemed to decrease trophic support. Haloperidol and risperidone increased Nrf2 and HO-1 gene expression, but only haloperidol upregulated NFκB and AMPK gene expression. Finally, astrocyte cultures confirmed the predominant effect of the tested antipsychotics on glia and their opposite effects on astrocytes. Therefore, antipsychotics cause functional alterations in the hippocampus. This information is important to drive future research for strategies to attenuate antipsychotics-induced neural dysfunction, focusing on glia.

Widespread Misinterpretation of pKa Terminology for Zwitterionic Compounds and Its Consequences.

The acid dissociation constant (pKa), which quantifies the propensity for a solute to donate a proton to its solvent, is crucial for drug design and synthesis, environmental fate studies, chemical manufacturing, and many other fields. Unfortunately, the terminology used for describing acid-base phenomena is sometimes inconsistent, causing large potential for misinterpretation. In this work, we examine a systematic confusion underlying the definition of "acidic" and "basic" pKa values for zwitterionic compounds. Due to this confusion, some pKa data are misrepresented in data repositories, including the widely used and highly trusted ChEMBL database. Such datasets are frequently used to supply training data for pKa prediction models, and hence, confusion and errors in the data make the model performance worse. Herein, we discuss the intricacies of this issue. We make suggestions for describing acid-base phenomena, training pKa prediction models, and stewarding pKa datasets, given the high potential for confusion and potentially high impact in downstream applications.

Functional characterization of four antenna-enriched odorant binding proteins in Rhaphuma horsfieldi reveals the importance of RhorOBP1 in odorant recognition and insecticide resistance

The cerambycid beetles are key players for the sustenance of biodiversity in the forest ecosystem, but in most cases are well known due to their harmfulness to agricultural and forest plants. Here, we characterized the odorant binding protein (OBP) gene family in Rhaphuma horsfieldi, emphasizing the roles of RhorOBP1 in odorant reception and insecticide sequestering. A homology-based search led to the identification of 35 RhorOBP genes with a major distribution in the Minus-C OBPs clade (21/35 genes). Expression profiles showed that RhorOBP1–RhorOBP4 had the abundant expression in antennae. Binding assays revealed that the four RhorOBPs exhibited diverse odorant response profiles tuned differentially to various classes of plant odorants, comprising walnut-derived host volatiles and ordinary floral scents. Two broadly tuned RhorOBP1 and RhorOBP2 exhibited different chain length-dependent binding properties to 10C12C alcohols, aldehydes or acetates. Compared with other three proteins, RhorOBP1 reduced the binding to ligands with high affinities at pH 5.0 (1.27–6.72-fold differences relative to pH 7.4). Molecular docking and point-mutation experiments confirmed that Ser107, Tyr118, Tyr119 and Phe120 situated in the binding pocket of RhorOBP1 were critical determinants for the recognition of 14, 15, 10 and 10 compounds, respectively. On the other hand, RhorOBP1 could strongly bind six insecticides, particularly chlorpyrifos (dissociation constant, Ki = 3.69 ± 0.74 μM). This study has provided insights into different binding properties of four antenna-enriched RhorOBPs in R. horsfieldi and identifies a dual role of RhorOBP1 in the binding of odorants and insecticides.

Enhanced opto-chemical sensing of phenolphthalein using thermally stable au-supported Titania-silica nanocomposites

Detecting acidic and basic species at a dynamic pH range with rapid response is crucial in the analytical field. Sol-gel-based thermally stable titania nanoparticles (TNPs), TNPs doped silica nanocomposite (TSNC), and Au-supported TSNC (ATS-NC) are synthesized for phenolphthalein sensing. ATS-NC possessed porous nanostructure, uniform particles distribution, and crystallite size of 4 nm, roughness of around 19 nm, and thickness ∼ 76 nm. ATS-NC exhibited large surface area ∼ 251 m2/g and a pore volume around 0.2 cm3/g. ATS-NC displayed a larger pKa (negative log of the acid dissociation constant) ∼ 10.3 compared to TSNC (∼ 10) and TNPs (∼ 9.8) at 553 nm. The rapid response time of ATS-NC is observed around 0.3 s against pH 12 compared to 0.36 s (TSNC) and 0.39 s (TNPs). Experimental findings suggested that ATS-NC has potential for quick and efficient pH sensing in various applications such as environmental monitoring and food science.