Allosteric inhibition abrogates dysregulated LFA-1 activation: Structural insight into mechanisms of diminished immunologic disease

Lymphocyte Function Associated antigen-1(LFA-1) has been implicated severely in the pathophysiology of inflammatory and autoimmune diseases. Its active and inactive conformations correlate with its diseased and non-diseased state respectively. This is determined by its degree of affinity for its intrinsic ligand (ICAM) at the active site and accompanying synergistic coordination at the α7 helix. This potentiates the role of inhibitors in disrupting this interaction allosterically. Herein, we present a first account of the structural dynamics which characterizes the inhibitory effect of a novel LFA-1 antagonist, Lifitegrast (SAR1118), upon binding to the I-domain allosteric site (IDAS) using molecular dynamics simulation. Findings from this study revealed that the inhibitor stabilized the closed conformation and reversed the open conformation to a low ICAM-affinity state (closed) as evidenced by the upward movement of the α7 helix and corresponding transitions at the active site. This in both cases favors the formation of the non-disease inactive form. Upon allosteric modulation, the inhibitor significantly restored protein stability, enhanced compactness and decreased residual fluctuation as crucial to its potency in the amelioration of immunological and inflammatory diseases which agrees with experimental studies. These findings could therefore serve as the basis for the exploration of the allosteric domain and its active site affinity modulation to aid the design of more specific and selective inhibitors.     

Emissive Properties and Intramolecular Charge Transfer of Pyrazoloquinoline Derivatives

The fluorescence properties of several pyrazoloquinoline derivatives were performed by stationary as well as by time-resolved spectrosopy. Non-donor-substituted compounds show a high quantum yield; transition dipole moments of absorption and fluorescence as well as experimental and calculated lifetimes are in excellent agreement. The donor-substituted compound DMA-DPPQ exhibits a charge transfer fluorescence in polar solvents. Additionally, dual fluorescence appears in polar protic solvents. The nature of the charge transfer state is discussed with respect to the the TICT model.     

Reactions of carbanions derived from α-substituted-methyl tolyl sulfones with quinone methides as Michael acceptors

Nucleophilic addition of α-halo-4-tolylsulfonyl methyl anions to quinone methides and subsequent reactions were studied. Three kinds of consecutive reaction products were isolated, depending on the substrate structures and reaction conditions. Two of them were identified as rearrangement products and one as the vicarious nucleophilic substitution (VNS) product. An unexpected 1,2-migration of the tosyl group was observed. The mechanism of the reactions is briefly discussed.     

Mitochondrial and peroxisomal population in post-pharyngeal glands of leaf-cutting ants after lipid supplementation

The post-pharyngeal gland (PPG) occurs in ants and some Sphecidae wasps. Among its several roles is the storage of lipids from food. In order to investigate the effect of lipids on the cell, especially on mitochondria and peroxisomes, the present study was aimed at examining the peroxisomal and mitochondrial population in the PPG of Atta sexdens rubropilosa after lipid supplementation by confocal laser scanning microscopy and transmission electron microscopy. Soybean oil provided as lipid supplement was not toxic for A. sexdens rubropilosa workers for the first 48 h and 120 h. However, the ultrastructural cytochemical analysis revealed an accumulation of lipid droplets in the PPGs of ants after lipid supplementation at 48 h and 120 h, and smaller lipid droplets in the basal membrane of the PPG epithelium, showing lipid mobilization from the PPG to the hemolymph. The lipid supplementation reduces the life expectancy of medium workers, probably due to the high lipid metabolism. Most importantly, the PPGs of medium workers of leaf-cutting A. sexdens rubropilosa is probably a specialized gland in the lipid metabolism, due to the increased mitochondrial and peroxisomal population inside cells after lipid supplementation; participation of peroxisomal population in the β-oxidation of long chain fatty acids into smaller chains and participation of mitochondrial population in the β-oxidation of fatty acids for energy, or mobilization of lipid derivatives from the PPG to hemolymph, a process that requires energy. However, the hypothesis that the PPGs convert lipids from food in aldehydes and/or hydrocarbons must be better investigated.     

Application of linear discriminant analysis to the study of dew chemistry on the basis of samples collected in Poland (2004–2005)

This paper presents the results of determination of selected characteristics (anions, cations, formaldehyde, hydrogen peroxide, phenols, TC, TIC, TOC and metals) in dew samples collected in six different sites in Poland. The influence of local parameters (e.g. wind speed, humidity) was investigated. Discriminant analysis was applied to the study of several dew samples collected from different sampling sites covering six agglomerations in Poland. Discriminant function analysis was used not only for classifying samples into different groups with a better than chance accuracy, but also for detecting the most important variables that discern between the groups of samples considered. In this way it was possible to identify which ions or other physicochemical features are responsible for the similarities or differences observed between different groups of dew samples. A good agreement with their origin and location was observed. It is interesting to note that the classification of all samples was dominated by pH, wind direction, pressure and temperature with a significant contribution of Na⁺ and Cl⁻ ions.      

Determination of azaarenes in oils using the LC‐APCI‐MS/MS technique: New environmental toxicant in food oils

A novel method to determine of azaarenes in refined and cold‐pressed vegetable oils and animal fats is reported. The method may be used to determine eight most important acridine derivatives (benz[a]acridine, dibenz[a,i]acridine, benz[c]acridine, dibenz[a,j]acridine, 7,9‐dimethylbenz[c]acridine, dibenz[a,h]acridine, dibenz[a,c]acridine, dibenz[c,h]acridine) at a high sensitivity (LOQ in the 2–25 ng kg^?1 range), high analyte recovery rates (70.7–98.7%), sufficient linearity within the studied concentration range (r > 0.97). The method is fast, simple, and needs no expensive clean‐up procedures to successfully determine the analytes. Azaarene concentration in the studied oil samples ranged from 2 to 250 ng kg^?1. Benz[a]acridine and dibenz[a,j]acridine were the compounds found most commonly and at the highest concentrations. The observed concentrations most probably reflected levels of environmental contamination of raw materials used to produce the analyzed oil/fat samples.     

Acrosome reaction in Octopus tankahkeei induced by calcium ionophore A23187 and a possible role of the acrosomal screw

The octopod sperm is unique especially in two aspects: the screw-shaped acrosome and its inner layered substructure (striation). The present study aims to investigate morphological changes of Octopus tankahkeei spermatozoa during the acrosome reaction (AR) and to pursue functions of the internal substructures revealed by inducing AR with the calcium ionophore A23187. Gradual changes of the spermatozoa were traced using fluorescence and electron microscopy. The AR process included the bulging, vesiculation, and dehiscence of the plasma membrane around the acrosome and the nucleus, as well as the vesiculation of the mitochondrial sheath. Membrane vesiculation outside the nucleus has never been reported in the order Octopoda. The rigid screw and the inner striation of the acrosome remained intact surmounting the nucleus, suggesting that these two structures have potential functions during fertilization. In addition, the detachment of the sperm head and the tail was commonly observed in this study, both in intact and acrosome-reacted sperm. Fluorescence microscopy revealed that the detached mitochondrial sheath usually gave weaker and more dispersive signals than the joint ones. This phenomenon implied that the intense energy release might promote the detachment of the mitochondrial sheath.     

Existence for dynamic contact of a stochastic viscoelastic Gao Beam

This work presents and analyzes a model for the vibrations of a viscoelastic Gao Beam, which may come in contact with a deformable random foundation and allows for stochastic inputs. The body force involves a stochastic integral that includes Brownian motion. In addition, the gap between the beam and the foundation is a stochastic process, which is one of the novelties in the paper, and contact is described with the normal compliance condition. The existence and uniqueness of strong solutions to the model is established and it is shown that the solutions are adapted to the filtration determined by a given Wiener process for the stochastic force noise term.     

Synthesis,physical, and thermodynamic properties of 1-alkyl-cyanopyridinium bis{(trifluoromethyl)sulfonyl}imide ionic liquids

Synthesis of new ionic liquids (ILs) viz. 1-butyl-3-cyanopyridinium bis{(trifluoromethyl)sulfonyl}imide, [BCN³Py][NTf₂], 1-hexyl-3-cyanopyridinium bis{(trifluoromethyl)sulfonyl}imide, [HCN³Py][NTf₂], 1-hexyl-4-cyanopyridinium bis{(trifluoromethyl)sulfonyl}imide, [HCN⁴Py][NTf₂], and 1-octyl-3-cyanopyridinium bis{(trifluoromethyl)sulfonyl}imide, [OCN³Py][NTf₂] were performed. The specific basic characterization of new compounds by NMR spectra, elementary analysis, water content and glass transition temperature as well as melting temperature, enthalpy of fusion and decomposition of compounds TG/DTA determined by the differential scanning calorimetry, DSC is presented. The heat capacity was measured at three temperatures (298.15, 323.15, and 353.15) K and at pressure 0.1 MPa. The effect of temperature on the density and viscosity is reported over the temperature range from (293.15 to 363.15) K and at 0.1 MPa. The density and viscosity correlation for these systems was provided by an empirical polynomial. From the density–temperature dependence, the isothermal expansion coefficient (volume expansivity), α, was calculated. The surface tension of pure ionic liquids was measured at 0.1 MPa at five temperatures (298.15, 308.15, 318.15, 328.15, and 338.15) K. The surface thermodynamic functions such as surface entropy and enthalpy, critical temperatures according to the Eötvös and Guggenheim definition and the total surface energy of the ILs studied were derived from the temperature dependence of the surface tension values. The parachor and speed of sound for pure ionic liquids were described within a range of temperature from (298.15 to 338.15) K. A qualitative analysis on these quantities in terms of molecular interactions is reported.     

Application of molecularly imprinted polymers to determine B1, B2, and B3 fumonisins in cereal products

The aim of this study was to develop an analytical method for qualitative and quantitative determination of the B₁, B_2, and B₃ fumonisins in cereal products. A LC coupled to an IT‐MS was used as the analytical instrument. The AFFINIMIP FumoZON Molecularly Imprinted Polymer SPE cartridges (Polyintell) were used to isolate fumonisins from the analyzed samples and the clean‐up step. Statistical parameters evaluated in some validation experiments were as follows: mean recovery 95–106%, precision <17% (expressed as recovery RSD). The developed method was used to determine fumonisins in 49 cereals (42 maize‐based and seven wheat‐based products). In most cases, concentrations of the studied compounds found in the analyzed samples were low. The highest total concentration of the B₁, B₂, and B₃ fumonisins was found in maize flour samples (range, 26–1102 μg/kg, mean 498 μg/kg).