The Carrot Phytoene Synthase 2 (DcPSY2) Promotes Salt Stress Tolerance through a Positive Regulation of Abscisic Acid and Abiotic-Related Genes in Nicotiana tabacum.

Background: Carotenoids, which are secondary metabolites derived from isoprenoids, play a crucial role in photo-protection and photosynthesis, and act as precursors for abscisic acid, a hormone that plays a significant role in plant abiotic stress responses. The biosynthesis of carotenoids in higher plants initiates with the production of phytoene from two geranylgeranyl pyrophosphate molecules. Phytoene synthase (PSY), an essential catalytic enzyme in the process, regulates this crucial step in the pathway. In Daucus carota L. (carrot), two PSY genes (DcPSY1 and DcPSY2) have been identified but only DcPSY2 expression is induced by ABA. Here we show that the ectopic expression of DcPSY2 in Nicotiana tabacum L. (tobacco) produces in L3 and L6 a significant increase in total carotenoids and chlorophyll a, and a significant increment in phytoene in the T1L6 line. Tobacco transgenic T1L3 and T1L6 lines subjected to chronic NaCl stress showed an increase of between 2 and 3- and 6-fold in survival rate relative to control lines, which correlates directly with an increase in the expression of endogenous carotenogenic and abiotic-related genes, and with ABA levels. Conclusions: These results provide evidence of the functionality of DcPSY2 in conferring salt stress tolerance in transgenic tobacco T1L3 and T1L6 lines.

SELEX based aptamers with diagnostic and entry inhibitor therapeutic potential for SARS-CoV-2.

Frequent mutation and variable immunological protection against vaccination is a common feature for COVID-19 pandemic. Early detection and confinement remain key to controlling further spread of infection. In response, we have developed an aptamer-based system that possesses both diagnostic and therapeutic potential towards the virus. A random aptamer library (~ 1017 molecules) was screened using systematic evolution of ligands by exponential enrichment (SELEX) and aptamer R was identified as a potent binder for the SARS-CoV-2 spike receptor binding domain (RBD) using in vitro binding assay. Using a pseudotyped viral entry assay we have shown that aptamer R specifically inhibited the entry of a SARS-CoV-2 pseudotyped virus in HEK293T-ACE2 cells but did not inhibit the entry of a Vesicular Stomatitis Virus (VSV) glycoprotein (G) pseudotyped virus, hence establishing its specificity towards SARS-CoV-2 spike protein. The antiviral potential of aptamers R and J (same central sequence as R but lacking flanked primer regions) was tested and showed 95.4% and 82.5% inhibition, respectively, against the SARS-CoV-2 virus. Finally, intermolecular interactions between the aptamers and the RBD domain were analyzed using in silico docking and molecular dynamics simulations that provided additional insight into the binding and inhibitory action of aptamers R and J.

ABA Biosynthesis- and Signaling-Related Gene Expression Differences between Sweet Cherry Fruits Suggest Attenuation of ABA Pathway in Bicolored Cultivars.

Fruit development involves exocarp color evolution. However, signals that control this process are still elusive. Differences between dark-red and bicolored sweet cherry cultivars rely on MYB factor gene mutations. Color evolution in bicolored fruits only occurs on the face receiving sunlight, suggesting the perception or response to color-inducing signals is affected. These color differences may be related to synthesis, perception or response to abscisic acid (ABA), a phytohormone responsible for non-climacteric fruit coloring. This work aimed to determine the involvement of ABA in the coloring process of color-contrasting varieties. Several phenolic accumulation patterns differed between bicolored 'Royal Rainier' and dark-red 'Lapins'. Transcript abundance of ABA biosynthetic genes (PavPSY, PavZEP and PavNCED1) decreased dramatically from the Pink to Red stage in 'Royal Rainier' but increased in 'Lapins', which correlated with a higher ABA content in this dark-red cultivar. Transcripts coding for ABA signaling (PavPP2Cs, PavSnRKs and PavMYB44.1) were almost undetectable at the Red stage in 'Royal Rainier'. Field trials revealed that 'Royal Rainier' color development was insensitive to exogenous ABA, whereas it increased in 'Lapins'. Furthermore, ABA treatment only increased transcript levels of signaling genes in 'Lapins'. Further studies may address if the ABA pathway is attenuated in bicolor cultivars.

Uncovering the Critical Factors that Enable Extractive Desulfurization of Fuels in Ionic Liquids and Deep Eutectic Solvents from Simulations.

Environmental regulatory agencies have implemented stringent restrictions on the permissible levels of sulfur compounds in fuel to reduce harmful emissions and improve air quality. Problematically, traditional desulfurization methods have shown low effectiveness in the removal of refractory sulfur compounds, e.g., thiophene (TS), dibenzothiophene (DBT), and 4-methyldibenzothiophene (MDBT). In this work, molecular dynamics (MD) simulations and free energy perturbation (FEP) have been applied to investigate the use of ionic liquids (ILs) and deep eutectic solvents (DESs) as efficient TS/DBT/MDBT extractants. For the IL simulations, the selected cation was 1-butyl-3-methylimidazolium [BMIM] and the anions included chloride [Cl], thiocyanate [SCN], tetrafluoroborate [BF4], hexafluorophosphate [PF6], and bis(trifluoromethylsulfonyl)amide [NTf2]. The DESs were composed of choline chloride with ethylene glycol (CCEtg) or with glycerol (CCGly). Calculation of excess chemical potentials predicted the ILs to be more promising extractants with energies lower by 1-3 kcal/mol compared to DESs. Increasing IL anion size was positively correlated to enhanced solvation of S-compounds, which was influenced by energetically dominant solute-anion interactions and favorable solute-[BMIM] π-π stacking. For the DESs, the solvent components offered a range of synergistic, yet comparatively weaker, electrostatic interactions that included hydrogen bonding and cation-π interactions. An in-depth analysis of the structure of IL and DES systems is presented, along with a discussion of the critical factors behind experimental trends of S-compound extraction efficiency.

Free Energy Calculations and Conformational Analysis of Dibenzo-30-crown-10 with Sm2+, Eu2+, and Three Halide Salts in THF Using the AMOEBA Force Field.

Crown ether complexes have been tailored for use in industrial separations of lanthanides (Ln) as a part of rare earth mining and refining. Dibenzo-30-crown-10 (DB30C10) is one of the most efficient complexants for the separation of rare earth mixtures based on the cation size. To understand the origin of this complexation, molecular dynamics (MD) simulations of DB30C10 have been performed using different combinations of divalent Sm and Eu and three halide salts Cl-, Br-, and I- in tetrahydrofuran (THF) solvent. DB30C10 was parameterized here for the polarizable atomic multipole optimized energetics for biomolecular simulation (AMOEBA) force field, and the existing parameters of THF, Sm2+, and Eu2+ were employed from our previous efforts. The large conformational fluctuations present in the DB30C10 systems were found to be dependent both on the identity of the lanthanide and halide complexes. For Cl- and Br- systems, there were no observed conformational changes at 200 ns, while in I- systems, there were two conformational changes with Sm2+ and one with Eu2+ within that same timeframe. In SmI2-DB30C10, there were three stages of conformational changes. In the first stage, the molecule is unfolded, in the second stage, the molecule is partly folded, and finally, in the third stage, the molecule is completely folded. Lastly, the Gibbs binding free energies of DB30C10 with SmBr2 and EuBr2 have been computed, which resulted in nearly identical ΔGcomp values for each lanthanide with Sm2+ being slightly more favorable. Considering the folding mechanism of the SmI2 system with DB30C10, the Gibbs binding free energies of DB30C10 and dicyclohexano-18-crown-6 (DCH18C6) with SmI2 were calculated separately and compared to probe their complexation affinities, in which the former was found to be more favorable.

Shorter Alkanesulfonate Carbon Chains Destabilize the Active Site Architecture of SsuD for Desulfonation.

Bacteria have evolved to utilize alternative organosulfur sources when sulfur is limiting. The SsuE/SsuD and MsuE/MsuD enzymes expressed when sulfur sources are restricted, are responsible for providing specific bacteria with sulfur in the form of alkanesulfonates. In this study, we evaluated why two structurally and functionally similar FMNH2-dependent monooxygenase enzymes (MsuD and SsuD) are needed for the acquisition of alkanesulfonates in some bacteria. In desulfonation assays, MsuD was able to utilize the entire range of alkanesulfonates (C1-C10). However, SsuD was not able to utilize smaller alkanesulfonate substrates. Interestingly, SsuD had a similar binding affinity for methanesulfonate (MES) (15 ± 1 µM) as MsuD (12 ± 1 µM) even though SsuD was not able to catalyze the desulfonation of the MES substrate. SsuD and MsuD showed decreased proteolytic susceptibility in the presence of FMNH2 with MES and octanesulfonate (OCS). Tighter loop closure was observed for the MsuD/FMNH2 complex with MES and OCS compared to SsuD under comparable conditions. Analysis of the SsuD/FMNH2/MES structure using accelerated molecular dynamics simulations found three different conformations for MES, demonstrating the instability of the bound structure. Even when MES was bound in a similar fashion to OCS within the active site, the smaller alkane chain resulted in a shift of FMNH2 so that it was no longer in a position to catalyze the desulfonation of MES. The active site of SsuD requires a longer alkane chain to maintain the appropriate architecture for desulfonation.

Molecular Dynamics and Free Energy Calculations of Dicyclohexano-18-crown-6 Diastereoisomers with Sm2+, Eu2+, Dy2+, Yb2+, Cf2+, and Three Halide Salts in Tetrahydrofuran and Acetonitrile Using the AMOEBA Force Field.

With the continual development of lanthanides (Ln) in current technological devices, an efficient separation process is needed that can recover greater amounts of these rare elements. Dicyclohexano-18-crown-6 (DCH18C6) is a crown ether that may be a promising candidate for Ln separation, but additional research is required. As such, molecular dynamics (MD) simulations have been performed on four divalent lanthanide halide salts (Sm2+, Eu2+, Dy2+, and Yb2+) and one divalent actinide halide salt (Cf2+) bound to three diastereoisomers of DCH18C6. Dy2+, Yb2+, Cf2+, DCH18C6, and tetrahydrofuran (THF) solvent were parameterized for the AMOEBA polarizable force field for the first time, whereas existing parameters for Sm2+ and Eu2+ were utilized from our previous efforts. A coordination number (CN) of six for Ln2+/An2+-O solvated in THF indicated that the cations interacted almost entirely with the oxygens of the polyether ring. A CN of one for Ln2+/An2+-N solvated in acetonitrile for systems containing iodide suggested that the N atom of acetonitrile was competitive with I- for cation interactions. Fluctuation between five and six CNs for Dy2+ and Yb2+ suggested that although the cations remained in the polyether ring, the size of the ring may not be an ideal fit as these cations possess comparatively smaller ionic radii. Gibbs binding free energies of Sm2+ in all DCH18C6 diastereoisomers solvated in THF were calculated. The binding free energy of the cis-syn-cis diastereoisomer was the most favorable, followed by cis-anti-cis, and then trans-anti-trans. Finally, two major types of conformation were observed for each diastereoisomer that were related to the electrostatic interactions and charge density of the cations.

Hydration of divalent lanthanides, Sm2+ and Eu2+ : A molecular dynamics study with polarizable AMOEBA force field.

The chemistry of divalent lanthanides, Ln2+ , is a growing sub-field of heavy element chemistry owing to new synthetic approaches. However, some theoretical aspects of these unusual cations are currently underdeveloped, especially as they relate to their dynamic properties in solution. In this work, we address the hydration of two of the classical Ln2+ cations, Sm2+ and Eu2+ , using atomic multipole optimized energetic for biomolecular applications (AMOEBA) force fields. These cations have not been parameterized to date with AMOEBA, and few studies are available because of their instability with respect to oxidation in aqueous media. Coordination numbers (CN's) of 8.2 and 8.1 respectively for Sm2+ and Eu2+ , and 8.8 for both Sm3+ and Eu3+ have been obtained and are in good agreement with the few available AIMD and X-ray absorption fine structures studies. The decreased CN of Ln2+ compared with Ln3+ arises from progressive water exchange events that indicates the gradual stabilization of 8-coordinate structures with respect to 9-coordinate geometries. Moreover, the effects of the chloride counter anions on the coordination of Ln2+ cations have been studied at different chloride concentrations in this work. Lastly, water exchange times of Ln2+ cations have been calculated to provide a comprehensive understanding of the behavior of Eu2+ and Sm2+ in aqueous chloride media.

Primer for Designing Main Protease (Mpro) Inhibitors of SARS-CoV-2.

The COVID-19 outbreak has been devastating, with hundreds of millions of infections and millions of deaths reported worldwide. In response, the application of structure-activity relationships (SAR) upon experimentally validated inhibitors of SARS-CoV-2 main protease (Mpro) may provide an avenue for the identification of new lead compounds active against COVID-19. Upon the basis of information gleaned from a combination of reported crystal structures and the docking of experimentally validated inhibitors, four "rules" for designing potent Mpro inhibitors have been proposed. The aim here is to guide medicinal chemists toward the most probable hits and to provide guidance on repurposing available structures as Mpro inhibitors. Experimental examination of our own previously reported inhibitors using the four "rules" identified a potential lead compound, the cathepsin inhibitor GB111-NH2, that was 2.3 times more potent than SARS-CoV-2 Mpro inhibitor N3.

Comparison between Ab Initio Molecular Dynamics and OPLS-Based Force Fields for Ionic Liquid Solvent Organization.

OPLS-based force fields (FFs) have been shown to provide accurate bulk-phase properties for a wide variety of imidazolium-based ionic liquids (ILs). However, the ability of OPLS to reproduce an IL solvent structure is not as well-validated given the relative lack of high-level theoretical or experimental data available for comparison. In this study, ab initio molecular dynamics (AIMD) simulations were performed for three widely used ILs: the 1-butyl-3-methylimidazolium cation with chloride, tetrafluoroborate, or hexafluorophosphate anions, that is, [BMIM][Cl], [BMIM][BF4], and [BMIM][PF6], respectively, as a basis for further assessment of two unique IL FFs: the ±0.8 charge-scaled OPLS-2009IL FF and the OPLS-VSIL FF. The OPLS-2009IL FF employs a traditional all-atom functional form, whereas the OPLS-VSIL FF was developed using a virtual site that offloads negative charge to inside the plane of the ring with careful attention given to reproducing hydrogen bonding. Detailed comparisons between AIMD and the OPLS FFs were made based on radial distribution functions (RDFs), combined distribution functions (CDFs), and spatial distribution functions (SDFs) to examine cation-anion interactions and π+-π+ stacking between the imidazolium rings. While both FFs were able to correctly capture the general solvent structure of these popular ILs, the OPLS-VSIL FF quantitatively reproduced interaction distances more accurately. In addition, this work provides further insights into the different short- and long-range structure patterns of these popular ILs.

Role of Extracellular Trap Release During Bacterial and Viral Infection.

Neutrophils are innate immune cells that play an essential role during the clearance of pathogens that can release chromatin structures coated by several cytoplasmatic and granular antibacterial proteins, called neutrophil extracellular traps (NETs). These supra-molecular structures are produced to kill or immobilize several types of microorganisms, including bacteria and viruses. The contribution of the NET release process (or NETosis) to acute inflammation or the prevention of pathogen spreading depends on the specific microorganism involved in triggering this response. Furthermore, studies highlight the role of innate cells different from neutrophils in triggering the release of extracellular traps during bacterial infection. This review summarizes the contribution of NETs during bacterial and viral infections, explaining the molecular mechanisms involved in their formation and the relationship with different components of such pathogens.

Molecular and Cellular Mechanisms Modulating Trained Immunity by Various Cell Types in Response to Pathogen Encounter.

The induction of trained immunity represents an emerging concept defined as the ability of innate immune cells to acquire a memory phenotype, which is a typical hallmark of the adaptive response. Key points modulated during the establishment of trained immunity include epigenetic, metabolic and functional changes in different innate-immune and non-immune cells. Regarding to epigenetic changes, it has been described that long non-coding RNAs (LncRNAs) act as molecular scaffolds to allow the assembly of chromatin-remodeling complexes that catalyze epigenetic changes on chromatin. On the other hand, relevant metabolic changes that occur during this process include increased glycolytic rate and the accumulation of metabolites from the tricarboxylic acid (TCA) cycle, which subsequently regulate the activity of histone-modifying enzymes that ultimately drive epigenetic changes. Functional consequences of established trained immunity include enhanced cytokine production, increased antigen presentation and augmented antimicrobial responses. In this article, we will discuss the current knowledge regarding the ability of different cell subsets to acquire a trained immune phenotype and the molecular mechanisms involved in triggering such a response. This knowledge will be helpful for the development of broad-spectrum therapies against infectious diseases based on the modulation of epigenetic and metabolic cues regulating the development of trained immunity.

Naturally occurring cancer-associated mutations disrupt oligomerization and activity of protein arginine methyltransferase 1 (PRMT1).

Protein arginine methylation is a posttranslational modification catalyzed by the protein arginine methyltransferase (PRMT) enzyme family. Dysregulated protein arginine methylation is linked to cancer and a variety of other human diseases. PRMT1 is the predominant PRMT isoform in mammalian cells and acts in pathways regulating transcription, DNA repair, apoptosis, and cell proliferation. PRMT1 dimer formation, which is required for methyltransferase activity, is mediated by interactions between a structure called the dimerization arm on one monomer and a surface of the Rossman Fold of the other monomer. Given the link between PRMT1 dysregulation and disease and the link between PRMT1 dimerization and activity, we searched the Catalogue of Somatic Mutations in Cancer (COSMIC) database to identify potential inactivating mutations occurring in the PRMT1 dimerization arm. We identified three mutations that correspond to W215L, Y220N, and M224V substitutions in human PRMT1V2 (isoform 1) (W197L, Y202N, M206V in rat PRMT1V1). Using a combination of site-directed mutagenesis, analytical ultracentrifugation, native PAGE, and activity assays, we found that these conservative substitutions surprisingly disrupt oligomer formation and substantially impair both S-adenosyl-L-methionine (AdoMet) binding and methyltransferase activity. Molecular dynamics simulations suggest that these substitutions introduce novel interactions within the dimerization arm that lock it in a conformation not conducive to dimer formation. These findings provide a clear, if putative, rationale for the contribution of these mutations to impaired arginine methylation in cells and corresponding health consequences.

Non-carboxylic acid inhibitors of aldose reductase based on N-substituted thiazolidinedione derivatives.

In search of dually active PPAR-modulators/aldose reductase (ALR2) inhibitors, 16 benzylidene thiazolidinedione derivatives, previously reported as partial PPARγ agonists, together with additional 18 structural congeners, were studied for aldose reductase inhibitory activity. While no compounds had dual property, our efforts led to the identification of promising inhibitors of ALR2. Eight compounds (11, 15-16, 20-24, 30) from the library of 33 compounds were identified as potent and selective inhibitors of ALR2. Compound 21 was the most effective and selective inhibitor with an IC50 value of 0.95 ± 0.11 and 13.52 ± 0.81 µM against ALR2 and aldehyde reductase (ALR1) enzymes, respectively. Molecular docking and dynamics studies were performed to understand inhibitor-enzyme interactions at the molecular level that determine the potency and selectivity. Compound 21 was further subjected to in silico and in vitro studies to evaluate the pharmacokinetic profile. Being less acidic (pKa = 9.8), the compound might have a superior plasma membrane permeability and reach the cytosolic ALR2. This fact together with excellent drug-likeness criteria points to improved bioavailability compared to the clinically used compound Epalrestat. The designed compounds represent a novel group of non-carboxylate inhibitors of aldose reductase with an improved physicochemical profile.

Partial Charges Optimized by Genetic Algorithms for Deep Eutectic Solvent Simulations.

Deep eutectic solvents (DESs) are a class of solvents often composed of ammonium-based chloride salts and a neutral hydrogen bond donor (HBD) at specific ratios. These cost-effective and environmentally friendly solvents have seen significant growth in multiple fields, including organic synthesis, and in materials and extractions because of their desirable properties. In the present work, a new software called genetic algorithm machine learning (GAML) was developed that utilizes a genetic algorithm (GA) approach to facilitate the development of optimized potentials for liquid simulation (OPLS)-based force field (FF) parameters for eight unique DESs based on three ammonium-based salts and five HBDs at multiple salt:HBD ratios. As an initial test of GAML, partial charges were created for 86 conventional solvents based on neutral organic molecules that yielded excellent overall mean absolute deviations (MADs) of 0.021 g/cm3, 0.63 kcal/mol, and 0.20 kcal/mol compared to experimental densities, heats of vaporization (ΔHvap), and free energies of hydration (ΔGhyd), respectively. FFs for DESs constructed from ethylammonium, N,N-diethylethanolammonium, and N-ethyl-N,N-dimethylethanolammonium chloride salts were then parameterized using GAML with exceptional agreement achieved at multiple temperatures for experimental densities, surface tensions, and viscosities with MADs of 0.024 g/cm3, 4.2 mN/m, and 5.3 cP, respectively.

Kobophenol A Inhibits Binding of Host ACE2 Receptor with Spike RBD Domain of SARS-CoV-2, a Lead Compound for Blocking COVID-19.

In the search for inhibitors of COVID-19, we have targeted the interaction between the human angiotensin-converting enzyme 2 (ACE2) receptor and the spike receptor binding domain (S1-RBD) of SARS-CoV-2. Virtual screening of a library of natural compounds identified Kobophenol A as a potential inhibitor. Kobophenol A was then found to block the interaction between the ACE2 receptor and S1-RBD in vitro with an IC50 of 1.81 ± 0.04 µM and inhibit SARS-CoV-2 viral infection in cells with an EC50 of 71.6 µM. Blind docking calculations identified two potential binding sites, and molecular dynamics simulations predicted binding free energies of -19.0 ± 4.3 and -24.9 ± 6.9 kcal/mol for Kobophenol A to the spike/ACE2 interface and the ACE2 hydrophobic pocket, respectively. In summary, Kobophenol A, identified through docking studies, is the first compound that inhibits SARS-CoV-2 binding to cells through blocking S1-RBD to the host ACE2 receptor and thus may serve as a good lead compound against COVID-19.

Substrate-Dependent Mobile Loop Conformational Changes in Alkanesulfonate Monooxygenase from Accelerated Molecular Dynamics.

Substrate-induced conformational changes present in alkanesulfonate monooxygenase (SsuD) are crucial to catalysis and lead to distinct interactions between a dynamic loop region and the active site. Accelerated molecular dynamics (aMD) simulations have been carried out to examine this potential correlation by studying wild-type SsuD and variant enzymes bound with different combinations of reduced flavin (FMNH2), C4a-peroxyflavin intermediate (FMNOO-), and octanesulfonate (OCS). Three distinct mobile loop conformations were identified: "open", "closed", and "semiclosed". The substrate-free SsuD system possessed a wide opening capable of providing full access for substrates to enter the active site. Upon binding FMNH2, SsuD adopts a closed conformation that would prevent unproductive oxidation reactions in the absence of OCS. Two salt bridges, Asp111-Arg263 and Glu205-Arg271, were identified as particularly important in maintaining the closed conformation. Experimental substitution of Arg271 to Ala did not alter the catalytic activity, but the variant in the presence of reduced flavin was more susceptible to proteolytic digestion compared to wild-type. With both FMNH2 and OCS bound in SsuD, a second conformation was formed dependent upon a favorable π-π interaction between His124 and Phe261. Accordingly, there was no observed activity with the F261W SsuD variant in steady-state kinetic assays. This semiclosed conformation may be more appropriate for accepting O2 into the binding pocket and/or may properly orient the active site for the ensuing oxygenolytic cleavage. Finally, simulations of SsuD simultaneously bound with FMNOO- and OCS found an open mobile loop region that suggests alternative flavin intermediates may participate in the reaction mechanism.

c-Phycocyanin primed silver nano conjugates: Studies on red blood cell stress resilience mechanism.

Green synthesis of metal-encased nutraceutical nano-hybrids has been a target for research over the last few years. In the present investigation, we have reported temperature dependent facile synthesis of silver nanoparticles using FDA approved c phycocyanin (cPC). The cPC conjugated silver nanoparticles (AgcPCNPs) were characterized by TEM, Zeta Potential, UV-vis, XPS, FTIR, and CD Spectroscopy. The temperature optimization studies suggested the synthesis of stable AgcPCNPs at 40 °C while at higher temperature system shows aggregated appearance. Molecular docking studies predicted the exclusive interaction of C, D, I, and J chains of cPC with the surface of AgNPs. Moreover, AgcPCNPs significantly (p < 0.1 %) counteract the toxic nature of AgNPs on red blood cell by measuring parameters like total RBC count, % hemolysis, % hematocrit, coagulation time, pH, electrolyte concentrations and degree of blood cell lipid peroxidation by the anti-oxidation mechanism. Skin fibroblast in vitro cell migration result suggeststhat AgcPCNPs enhanced the degree of cell movement towards the wound area. Data obtained collectively demonstrate that AgcPCNPs can be a better agent in the dermal wound healing with reduced toxicity with the bi-phasic advantage of cPC as a wound healer and Ag nano-metal as an anti-bacterial agent.

Accurate Diels-Alder Energies and Endo Selectivity in Ionic Liquids Using the OPLS-VSIL Force Field.

Our recently developed optimized potentials for liquid simulations-virtual site ionic liquid (OPLS-VSIL) force field has been shown to provide accurate bulk phase properties and local ion-ion interactions for a wide variety of imidazolium-based ionic liquids. The force field features a virtual site that offloads negative charge to inside the plane of the ring with careful attention given to hydrogen bonding interactions. In this study, the Diels-Alder reaction between cyclopentadiene and methyl acrylate was computationally investigated in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate, [BMIM][PF6], as a basis for the validation of the OPLS-VSIL to properly reproduce a reaction medium environment. Mixed ab initio quantum mechanics and molecular mechanics (QM/MM) calculations coupled to free energy perturbation and Monte Carlo sampling (FEP/MC) that utilized M06-2X/6-31G(d) and OPLS-VSIL gave activation free energy barriers of 14.9 and 16.0 kcal/mol for the endo-cis and exo-cis Diels-Alder reaction pathways, respectively (exptl. ΔH‡ of 14.6 kcal/mol). The endo selectivity trend was correctly predicted with a calculated 73% endo preference. The rate and selectivity enhancements present in the endo conformation were found to arise from preferential hydrogen bonding with the exposed C4 ring hydrogen on the BMIM cation. Weaker electronic stabilization of the exo transition state was predicted. For comparison, our earlier ±0.8 charge-scaled OPLS-2009IL force field also yielded a ΔG‡ of 14.9 kcal/mol for the favorable endo reaction pathway but did not adequately capture the highly organized solvent interactions present between the cation and Diels-Alder transition state.

Expression of estrogen receptor beta (ERß) and its prognostic value in pleural mesothelioma.

BACKGROUND: Overexpression of estrogen receptors in malignant pleural mesothelioma has shown an independent relation with a better prognosis of survival, and the use of selective estrogen receptor beta (ERß) agonists increases the susceptibility to antitumor treatment. METHODS: This was a retrospective single center study that analyzed the response of malignant pleural mesothelioma with an expression of ERß to first-line chemotherapy. The study included patients with pleural mesothelioma pathologically confirmed between 2013 and 2016 at the National Institute for Respiratory Disease (INER), who underwent an immunohistochemistry assay for ERß (mouse monoclonal antibody PPG5/10). The primary endpoint was the response to chemotherapy based on RECIST 1.1 according to the ERß expression; secondary outcomes were the overall survival (OS) and progression-free survival (PFS). RESULTS: We included 22 patients, regarding the expression of ERß, 17 (77.2%) patients had high or moderate degree, while 5 (22.7%) had low degree or null expression. The response to treatment as by RECIST 1.1, 12 (54.5%) had partial response, 5 (22.7%) had stable disease, and 3 (13.6%) had progression. None of the patients had a complete response. Of those who had a partial response, 9 (75%) had a high or moderate degree of ERß expression in tumor cells, and 3 (25%) had a low or null degree of expression. CONCLUSIONS: High and moderate expression of ERß group with advanced clinical stage malignant pleural mesothelioma was associated with a tendency of higher OS and better response to chemotherapy treatment resulting in longer PFS although statistical significance was not achieved.