GPR55 Receptor Activation by the N-Acyl Dopamine Family Lipids Induces Apoptosis in Cancer Cells via the Nitric Oxide Synthase (nNOS) Over-Stimulation

GPR55 is a GPCR of the non-CB1/CB2 cannabinoid receptor family, which is activated by lysophosphatidylinositol (LPI) and stimulates the proliferation of cancer cells. Anandamide, a bioactive lipid endocannabinoid, acts as a biased agonist of GPR55 and induces cancer cell death, but is unstable and psychoactive. We hypothesized that other endocannabinoids and structurally similar compounds, which are more hydrolytically stable, could also induce cancer cell death via GPR55 activation. We chemically synthesized and tested a set of fatty acid amides and esters for cell death induction via GPR55 activation. The most active compounds appeared to be N-acyl dopamines, especially N-docosahexaenoyl dopamine (DHA-DA). Using a panel of cancer cell lines and a set of receptor and intracellular signal transduction machinery inhibitors together with cell viability, Ca²⁺, NO, ROS (reactive oxygen species) and gene expression measurement, we showed for the first time that for these compounds, the mechanism of cell death induction differed from that published for anandamide and included neuronal nitric oxide synthase (nNOS) overstimulation with concomitant oxidative stress induction. The combination of DHA-DA with LPI, which normally stimulates cancer proliferation and is increased in cancer setting, had an increased cytotoxicity for the cancer cells indicating a therapeutic potential.     

Impact of A134 and E218 Amino Acid Residues of Tropomyosin on Its Flexibility and Function

Tropomyosin (Tpm) is one of the major actin-binding proteins that play a crucial role in the regulation of muscle contraction. The flexibility of the Tpm molecule is believed to be vital for its functioning, although its role and significance are under discussion. We choose two sites of the Tpm molecule that presumably have high flexibility and stabilized them with the A134L or E218L substitutions. Applying differential scanning calorimetry (DSC), molecular dynamics (MD), co-sedimentation, trypsin digestion, and in vitro motility assay, we characterized the properties of Tpm molecules with these substitutions. The A134L mutation prevented proteolysis of Tpm molecule by trypsin, and both substitutions increased the thermal stability of Tpm and its bending stiffness estimated from MD simulation. None of these mutations affected the primary binding of Tpm to F-actin; still, both of them increased the thermal stability of the actin-Tpm complex and maximal sliding velocity of regulated thin filaments in vitro at a saturating Ca²⁺ concentration. However, the mutations differently affected the Ca²⁺ sensitivity of the sliding velocity and pulling force produced by myosin heads. The data suggest that both regions of instability are essential for correct regulation and fine-tuning of Ca²⁺-dependent interaction of myosin heads with F-actin.     

Casimir Effect in Optoelectronic Devices Using Ferrofluids

Some of the modern electronic and optoelectronic devices exploit ferrofluids contained in narrow gaps between two material plates. When the width of the gap becomes below a micrometer, the boundary plates are subjected to the Casimir force arising from the zero-point and thermal fluctuations of the electromagnetic field. These forces should be taken into account in microdevices with the dimensions decreased to below a micrometer. In this paper, we review recently performed calculations of the attractive Casimir pressure in three-layer systems containing a ferrofluid. We also find the ferrofluidic system where the Casimir pressure is repulsive. This result is obtained in the framework of the fundamental Lifshitz theory of van der Waals and Casimir forces. The conclusion is made that enhanced repulsion due to the presence of a ferrofluid may prevent from sticking of closely spaced elements of a microdevice.     

The influence of transition metals – Fe,Co, Cu on transformation of organic matters from Domanic rocks in hydrothermal catalytic system

Character of conversion of organic matter from Domanic rocks of Pervomaiskoye field (Tatarstan) of Semiluki horizon of upper Devonian deposits in the hydrothermal-catalytic system at temperature of 300?°C in carbon dioxide medium was studied with the application of complex of oil-soluble precursors of catalysts containing Fe, Co, and Cu. In presence of catalysts complex, content of organic extract increases, in which content of hydrocarbon fractions, saturated and aromatic hydrocarbons, increases 1.5 times, while resins content decreases by two times. As result of kerogen destruction in products of experiments, the content of asphaltenes and carbonaceous substances such as carbenes and carboides increase.     

Fischer–Tropsch synthesis using plug-through contactor membranes based on permeable composite monoliths. Selectivity control by porous structure parameters and membrane geometry

The Fischer–Tropsch synthesis using a contactor membrane reactor was studied varying pore size distribution parameters and membrane geometry. These parameters are responsible for the magnitude of the diffusion constrains and, therefore, correlate with the FTS process productivity and selectivity. The nature of the observed correlations is discussed.     

Macroporous carbon aerogel as a novel adsorbent for immobilized enzymes and a support for the lipase-active heterogeneous biocatalysts for conversion of triglycerides and fatty acids

A macroporous carbon aerogel (MCA) was produced by in situ synthesis of multi-walled carbon nanotubes (CNTs) via catalytic high-temperature decomposition of ethylene over the supported Fe:Co catalyst. A three-dimensional framework of ball-shaped MCA granules was formed by chaotic interlacing of growing CNTs and mechanical strength of the granules was high enough for their promising application in heterogeneous processes, in particular, bioconversion of fatty acids. The macroporous carbon aerogel was investigated as a novel support for adsorptive immobilization of an enzyme—Thermomyces lanuginosus lipase, followed by preparation of the lipase-active heterogeneous biocatalysts. It was found that the efficient and tight adsorption of the lipase on MCA occurred due to hydrophobic interactions. The amount of the lipase adsorbed in one dense adsorptive layer was equal to 110 mg per 1 g of the carbon aerogel. The lipase adsorbed in the 1st adsorptive layer possessed the maximum activity, 700–800 U/mg. The lipase-active heterogeneous biocatalysts were studied in the periodic processes of hydrolysis of emulsified triglycerides (tributyrin), interesterification of vegetable oil with ethyl acetate, and esterification of fatty acids (butyric C4:0, capric C10:0, and stearic C18:0) with isopentanol. It was found that T. lanuginosus lipase lost significantly its enzymatic activity during adsorption on the carbon aerogel; possible causes of the negative effect of such immobilization were discussed. The specific activity of the adsorbed lipase, as well as activity and stability of the biocatalysts depended foremost on the type of the reaction performed. The maximum activities of the biocatalysts were determined to be approximately 75·10³ and 2.5 U/g in tributyrin hydrolysis (aqueous media) and esterification of fatty acid (non-aqueous media), respectively. Stability of the biocatalysts was very high in the esterification reaction due to accumulation of essential water inside MCA. The lipase-active biocatalysts carried out the synthesis of isopentyl caprinate in organic solvents (hexane?+?diethyl ether) for several 100 h at 40 °C.