Fluorine Atoms on C6H5-Corrole Affect the Interaction with Mpro and PLpro Proteases of SARS-CoV-2: Molecular Docking and 2D-QSAR Approaches

The chymotrypsin-like cysteine protease (3CL^pro, also known as main protease—M^pro) and papain-like protease (PL^pro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been used as the main targets for screening potential synthetic inhibitors for posterior in vitro evaluation of the most promising compounds. In this sense, the present work reports for the first time the evaluation of the interaction between M^pro/PL^pro with a series of 17 porphyrin analogues-corrole (C1), meso-aryl-corrole (C2), and 15 fluorinated-meso-aryl-corrole derivatives (C3–C17) via molecular docking calculations. The impact of fluorine atoms on meso-aryl-corrole structure was also evaluated in terms of binding affinity and physical-chemical properties by two-dimensional quantitative structure–activity relationship (2D-QSAR). The presence of phenyl moieties increased the binding capacity of corrole for both proteases and depending on the position of fluorine atoms might impact positively or negatively the binding capacity. For M^pro the para-fluorine atoms might decrease drastically the binding capacity, while for PL^pro there was a certain increase in the binding affinity of fluorinated-corroles with the increase of fluorine atoms into meso-aryl-corrole structure mainly from tri-fluorinated insertions. The 2D-QSAR models indicated two separated regions of higher and lower affinity for M^pro:C1–C17 based on dual electronic parameters (σ_I and σ_R), as well as one model was obtained with a correlation between the docking score value of M^pro:C2–C17 and the corresponding ¹³C nuclear magnetic resonance (NMR) chemical shifts of the sp² carbon atoms (δ_C-1 and δ_C-2) of C2–C17. Overall, the fluorinated-meso-aryl-corrole derivatives showed favorable in silico parameters as potential synthetic compounds for future in vitro assays on the inhibition of SARS-CoV-2 replication.     

Photochemical Synthesis of Silver Hydrosol Stabilized by Carbonate Ions and Study of Its Bactericidal Impact on Escherichia coli: Direct and Indirect Effects

The great attention paid to silver nanoparticles is largely related to their antibacterial and antiviral effects and their possible use as efficient biocidal agents. Silver nanoparticles are being widely introduced into various areas of life, including industry, medicine, and agriculture. This leads to their spreading and entering the environment, which generates the potential risk of toxic effect on humans and other biological organisms. Proposed paper describes the preparation of silver hydrosols containing spherical metal nanoparticles by photochemical reduction of Ag⁺ ions with oxalate ions. In deaerated solutions, this gives ~10 nm particles, while in aerated solutions, ~20 nm particles with inclusion of the oxide Ag₂O are obtained. Nanoparticles inhibit the bacterium Escherichia coli and suppress the cell growth at concentrations of ~1 × 10⁻⁶–1 × 10⁻⁴ mol L⁻¹. Silver particles cause the loss of pili and deformation and destruction of cell membranes. A mechanism of antibacterial action was proposed, taking into account indirect suppressing action of Ag⁺ ions released upon the oxidative metal dissolution and direct (contact) action of nanoparticles on bacterial cells, resulting in a change in the shape and destruction of the bacteria.     

The Therapeutic Role of Exercise and Probiotics in Stressful Brain Conditions

Oxidative stress has been recognized as a contributing factor in aging and in the progression of multiple neurological disorders such as Parkinson’s disease, Alzheimer’s dementia, ischemic stroke, and head and spinal cord injury. The increased production of reactive oxygen species (ROS) has been associated with mitochondrial dysfunction, altered metal homeostasis, and compromised brain antioxidant defence. All these changes have been reported to directly affect synaptic activity and neurotransmission in neurons, leading to cognitive dysfunction. In this context two non-invasive strategies could be employed in an attempt to improve the aforementioned stressful brain status. In this regard, it has been shown that exercise could increase the resistance against oxidative stress, thus providing enhanced neuroprotection. Indeed, there is evidence suggesting that regular physical exercise diminishes BBB permeability as it reinforces antioxidative capacity, reduces oxidative stress, and has anti-inflammatory effects. However, the differential effects of different types of exercise (aerobic exhausted exercise, anaerobic exercise, or the combination of both types) and the duration of physical activity will be also addressed in this review as likely determinants of therapeutic efficacy. The second proposed strategy is related to the use of probiotics, which can also reduce some biomarkers of oxidative stress and inflammatory cytokines, although their underlying mechanisms of action remain unclear. Moreover, various probiotics produce neuroactive molecules that directly or indirectly impact signalling in the brain. In this review, we will discuss how physical activity can be incorporated as a component of therapeutic strategies in oxidative stress-based neurological disorders along with the augmentation of probiotics intake.     

A hash-based index for processing frequent updates and continuous location-based range queries

Knowledge and Information Systems - Wide range of location-based services and sensors in GIS have to manage moving objects that change their position with respect to time. These applications...     

苯甲酰脲类杀虫剂研究进展

从生物学的观点结合化学的知识介绍了苯甲酰脲类几丁质合成抑制剂类杀虫剂的发展概况、作用机制、致毒方式、毒性和代表性品种,分析了其应用中存在的主要问题及解决途径,并对其发展趋势及前景进行了讨论和对策思考.     

Studies of Membrane Topology of Mitochondrial Cholesterol Hydroxylases CYPs 27A1 and 11A1

Mitochondrial cytochrome P450 enzymes (CYP or P450, EC 1.14.13.15) play an important role in metabolism of cholesterol. CYP27A1 hydroxylates cholesterol at position 27 and, thus, initiates cholesterol removal from many extrahepatic tissues. CYP11A1 is a steroidogenic P450 that converts cholesterol to pregnenolone, the first step in the biosynthesis of all steroid hormones. We utilized a new approach to study membrane topology of CYPs 27A1 and 11A1. This approach involves heterologous expression of membrane-bound P450 in E. coli, isolation of the P450-containing E. coli membranes, treatment of the membranes with protease, removal of the digested soluble portion and extraction of the membrane-associated peptides, which are then identified by mass spectrometry. By using this approach, we found four membrane-interacting peptides in CYP27A1, and two peptides in CYP11A1. Peptides in CYP27A1 represent a contiguous portion of the polypeptide chain (residues 210–251) corresponding to the putative F-G loop and adjacent portions of the F and G helices. Peptides in CYP11A1 are from the putative F-G loop (residues 218–225) and the C-terminal portion of the G helix (residues 238–250). This data is consistent with those obtained previously by us and others and provide new information about the membrane topology of CYPs 27A1 and 11A1.     

Physico-Chemical Characterisation of Lipids from <Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis> (L.) and <Emphasis Type="Italic">Rapana venosa</Emphasis> and their Healing Properties on Skin Burns

Black Sea molluscs and gastropods are the most studied organisms from the Romanian littoral zone. In particular, those from the Mytilidae species are of great interest because biochemical investigations have shown that they can be sources of biological active substances which can have different applications (e.g. food additives). We report here the extraction of lipids from two different species of molluscs (Mytilus galloprovincialis L., Mediterranean mussel) and gastropods (Rapana venosa, hard-shell clam). The extracts were evaluated in terms of antioxidant and composition properties and their healing properties were tested on skin burns in Wistar rats. Our studies proved that the two lipid extracts contained a relatively complex distribution of compounds, in terms of characteristic indices, polyunsaturated fatty acids (PUFA) and vitamins E and D. The presence of such compounds rendered the extracts very efficient in healing induced skin burns in Wistar rats. The histological analysis showed a reduction in the time of healing (12-13 and 13-15 days for the Mytilus galloprovincialis (L.) Rapana venosa extracts, respectively) compared to 20-22 for untreated animals, based on results from tissues and blood samples. Our investigations have been proved to be promising in terms of future potential applications of the extracts as skin-care products, cosmetics and/or pharmaceutical preparations owing to their dermorestitutive properties.     

Polyaniline–silver composites prepared by the oxidation of aniline with silver nitrate in acetic acid solutions

The reaction between two non‐conducting chemicals, aniline and silver nitrate, yields a composite of two conducting components, polyaniline and metallic silver. Such conducting polymer composites combine the electrical properties of metals and the materials properties of polymers. In the present study, aniline was oxidized with silver nitrate in solutions of acetic acid; in this context, aniline oligomers are often a major component of the oxidation products. An insoluble precipitate of silver acetate is also present in the samples. The optimization of reaction conditions with respect to aniline and acetic acid concentrations leads to a conductivity of the composite as high as 8000 S cm^?1 at ca 70 wt% (ca 21 vol%) of silver. A sufficient concentration of acetic acid, as well as a time extending to several weeks, has to be provided for the successful polymerization of aniline. Polyaniline is present as nanotubes or nanobrushes composed of thin nanowires. The average size of the silver nanoparticles is 30–50 nm; silver nanowires are also observed. Copyright © 2009 Society of Chemical Industry     

Electromagnetic radiation shielding by composites of conducting polymers and wood

Polyaniline or polypyrrole composites with fir or oak wood have been prepared by in situ polymerization of the corresponding monomers in an aqueous suspension of wood sawdust. The percolation threshold of compressed coated particles is located below 5 wt % of the conducting component and, above this limit, the conductivity of most composites was higher than 10^?3 S cm^?1. The conductivity of composites containing ca 30 wt % of conducting polymer was of the order of 10^?1 S cm^?1, an order of magnitude lower than that of the corresponding homopolymers, polyaniline and polypyrrole. The conductivity stability has been tested at 175°C. The polypyrrole‐based composites generally lasted for a longer time than pyrrole homopolymers, also on account of the improved mechanical integrity of the samples provided by the presence of wood. The reverse order was found with polyaniline composites. The dielectric properties of the composites were determined in the range of 100 MHz–3 GHz, indicating that thick layers of composite material, ～ 100 mm, are needed for the screening of the electromagnetic radiation below ?10 dB level in this frequency range. Nevertheless, considering the potential production cost of composites and their low weight, such composite materials could be of practical interest in the shielding of electromagnetic interference. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 807–814, 2005