Ion trapping model of the ac conductivity in disordered solids.

In this paper, we develop an approach based on ions trapping to describe the conductivity spectra in disordered solids. Applying the multiple trapping model and the diffusion equation for ions, we obtained a new expression for the ac conductivity, which allows us to describe the conductivity spectra in wide ranges of frequencies and temperatures. In the high-temperature region, the new expression for the ac conductivity reproduces the Jonscher behavior, and with decreasing temperatures transforms into an expression of the NCL-type.

Multi-Addressed Fiber Bragg Structures for Microwave-Photonic Sensor Systems.

The new theory and technique of Multi-Addressed Fiber Bragg Structure (MAFBS) usage in Microwave Photonics Sensor Systems (MPSS) is presented. This theory is the logical evolution of the theory of Addressed Fiber Bragg Structure (AFBS) usage as sensors in MPSS. The mathematical model of additive response from a single MAFBS is presented.

Synthesis and anti-cancer activities of glycosides and glycoconjugates of diterpenoid isosteviol.

A series of glycosides and glycoconjugates of diterpenoid isosteviol (16-oxo--beyeran-19-oic acid) with various monosaccharide residues were synthesized and their cytotoxicity against some human cancer and normal cell lines was assayed. Most of the synthesized compounds demonstrated moderate to significant cytotoxicity against human cancer cell lines M-HeLa and MCF-7. Three lead compounds exhibited selective cytotoxic activities against M-HeLa (IC = 10.

Direct interaction of fibrinogen with lipid microparticles modulates clotting kinetics and clot structure.

Extensive studies revealed the role of blood lipid microparticles (liposomes, microvesicles) in activation of coagulation cascade. The direct interaction of fibrinogen/fibrin with lipid surfaces and its consequence for hemostasis received much less attention. We observed pronounced changes in both clot morphology and kinetics of fibrin clotting in the presence of artificial liposomes.

Synthesis and cytotoxicity of the conjugates of diterpenoid isosteviol and -acetyl-D-glucosamine.

A series of conjugates of diterpenoid isosteviol (16-oxo--beyeran-19-oic acid) and -acetyl-D-glucosamine was synthesised and their cytotoxicity against several human cancer cell lines (M-Hela, MCF-7, Hep G2, Panc-1, PC-3), as well as normal human cell lines (WI-38, Chang liver) was assayed. Most of the conjugates were found to be cytotoxic against the mentioned cancer cell lines in the range of IC values 13-89 µM. Two lead compounds and showed selective cytotoxicity against M-Hela (IC 13 and 14 µM) that was two times as high as the cytotoxicity of the anti-cancer drug Tamoxifen in control (IC 28 µM).

Coarse-grained molecular dynamics of membrane semitoroidal pore formation in model lipid-peptide systems.

Transmembrane pores play an important role in various cell processes. However, the detailed structures of these pores and their influence on the membrane properties remain undetermined. We performed microsecond coarse-grained molecular dynamics simulations to study the interaction of cationic β-structural peptides with multicomponent lipid bilayers consisting of two types of anionic (POPS, POPI) and two types of zwitterionic (POPE, POPC) lipids.

The Native Monomer of Bacillus Pumilus Ribonuclease Does Not Exist Extracellularly.

Supported by crystallography studies, secreted ribonuclease of (binase) has long been considered to be monomeric in form. Recent evidence obtained using native polyacrylamide gel electrophoresis and size-exclusion chromatography suggests that binase is in fact dimeric. To eliminate ambiguity and contradictions in the data we have measured conformational changes, hypochromic effect, and hydrodynamic radius of binase.

Molecular structure and properties of κ-carrageenan-gelatin gels.

Rheological studies, FTIR spectroscopy and a molecular docking approach were used to explore the structural basis of the peculiar physicochemical properties of gelatin gels modified with a κ-carrageenan admixture. Mixed gel properties are affected by the polysaccharide-to-gelatin ratio, Z, and can be divided into two categories. At low ratios, the strength of mixed gels varies insignificantly compared to gelatin due to the similar structures of the gels.

Spatial structures of rhamnogalacturonan I in gel and colloidal solution identified by 1D and 2D-FTIR spectroscopy.

Rhamnogalacturonan I (RG-I), a polysaccharide found in different types of plant cell walls, fulfills specific functions, the structural basis of which remains unclear. Generalized 2D correlation FTIR spectroscopy with dehydration was employed to reveal the structure and interactions in flax RG-I solution and microwave treated gel. Varying water content allowed emphasizing a role of solvent in maintaining different structures.

Effect of ergosterol on the fungal membrane properties. All-atom and coarse-grained molecular dynamics study.

Cell membranes are complex multicomponent systems consisting of thousands of different lipids with numerous embedded membrane proteins and many types of sterols. We used all-atom and coarse-grained molecular dynamics simulations to study the structural and dynamical properties of phospholipid bilayers containing four types of phospholipids and different amount of ergosterol, main sterol component in the fungal membranes. To characterize the influence of ergosterol on the membrane properties we analyzed the surface area per lipid, bilayer thickness, area compressibility modulus, mass density profiles, deuterium order parameters, and lateral diffusion coefficients.

NMR structure, conformational dynamics, and biological activity of PsDef1 defensin from Pinus sylvestris.

Plants have developed a complex defense response system against pests and pathogens. Defensins, produced by plants as part of their innate immune response, form the family of small, basic, cysteine-rich proteins with activity primarily directed against fungal pathogens. In addition, plant defensins can show antibacterial activity and protease and insect amylase inhibitory activities.

Interaction of Scots Pine Defensin with Model Membrane by Coarse-Grained Molecular Dynamics.

Plant defensins are a part of the innate immune system of plants that acts against a broad range of pathogens. Many plant defensins, including pine defensins, show strong antifungal activity that is associated with their ability to penetrate into the fungal cell membrane. However, the exact molecular mechanism of their action remains poorly defined.

Macromolecular Crowding Modulates Actomyosin Kinetics.

Actomyosin kinetics is usually studied in dilute solutions, which do not reflect conditions in the cytoplasm. In cells, myosin and actin work in a dense macromolecular environment. High concentrations of macromolecules dramatically reduce the amount of free space available for all solutes, which results in an effective increase of the solutes' chemical potential and protein stabilization.