Uncoupling protein mediates electrophoretic transport of protons and anions across the inner membrane brown adipose tissue mitochondria. The mechanism site proton transport, by which fatty acids activate relationship between anion are unknown. We used fluorescent probes to measure H+ in vesicles reconstituted with purified uncoupling carried out a comparative study effects laurate its close analogue, undecanesulfonate. Undecanesulfonate was transported Km value similar that observed for as...

Silybin and related flavonolignans form a major part of the Silybum marianum extract, silymarin, which has been used to treat liver diseases for hundreds years. Although regarded as safe, many extract constituents remain thus far untested their possible effects on biotransformation enzymes. Cytochromes P450 (CYP) are very important in this regard. We tested effect four flavonolignans: silybin, its hemisynthetic derivative dehydrosilybin, silydianin, silycristin three specific CYP activities:...

Resolution of inflammation requires clearance activated neutrophils by phagocytes in a manner that protects adjacent tissues from injury. Mechanisms governing apoptosis and inflamed areas are still poorly understood. We used dimethylsulfoxide-differentiated HL-60 cells showing inducible oxidase activity to study NADPH oxidase-induced pathways typical neutrophils. Activation the phorbol myristate acetate caused oxidative stress as shown production superoxide hydrogen peroxide, depletion...

The uncoupling protein generates heat by catalyzing electrophoretic proton transport across the inner membrane of brown adipose tissue mitochondria. It also transports Cl- and other monovalent anions, both anion are inhibited purine nucleotides. Several long-standing hypotheses bear on specific aspects transport, H+ nucleotide gating mechanisms in protein. We reevaluated these mitochondria liposomes reconstituted with purified protein; GDP inhibition is strictly noncompetitive unaffected...

The xenobiotic-mediated induction of three major human liver cytochrome P450 genes, CYP2B6, CYP2C9, and CYP3A4, is known to be regulated by the constitutive androstane receptor (CAR) pregnane X (PXR). CAR PXR are regulated, at least in part, glucocorticoid (GR) hypothesis a signal transduction cascade GR-[CAR/PXR]-P450 has been proposed. This study was aimed testing this primary hepatocytes using tubulin network disrupting agent colchicine. Colchicine (COL) decreased both basal rifampicin-...

Primary regulation of uncoupling protein is mediated by purine nucleotides, which bind to the and allosterically inhibit fatty acid-induced proton transport. To gain increased understanding nucleotide regulation, we evaluated role basic amino acid residues using site-directed mutagenesis. Mutant wild-type proteins were expressed in yeast, purified, reconstituted into liposomes. We studied binding as well inhibition transport six mutant proteins. None mutations interfered with Two lysine...

Osmotic changes represent a burden for the body and their limitation would be beneficial. We hypothesized that ubiquitous natural compounds could guard against cytotoxic effects of osmotic stress. evaluated anti-hypertonic mechanism quercetin 2,3-dehydrosilybin in H9c2 cells vitro.

Fatty acid (FA) uniport via mitochondrial uncoupling protein (UcP) was detected fluorometrically with PBFI, potassium‐binding benzofuran phthalate and SPQ, 6‐methoxy‐ N ‐(3‐sulfopropyl)‐quinolinium, indicating K + H , respectively. The FA structural patterns required for flip‐flop, UcP‐mediated uniport, activation of transport in proteoliposomes, inhibition Cl − by FA, were identical. Positive responses found exclusively which able to flip‐flop a protonated form across the membrane no...

Free fatty acids (FA) were found which did not acidify liposome interior. This is interpreted as their inability to rapidly flip‐flop across the lipid bilayer. However, they able partition in lipids detected directly using HPLC or from shift of equilibrium binding acrylodated intestinal protein (ADIFAB) presence vesicles. Various bipolar FA, such 12‐hydroxylauric acid, dicarboxylic acids, FA with benzene ring at tail be inactive this way. A phenomenon shielding, where an additional alkyl...

MicroRNA hsa-miR-29 was connected to a number of malignancies. Its target genes are many, among them Mcl-1 that is expressed in three possible isoforms, one which anti-apoptotic and another pro-apoptotic. Ratio these two isoforms appears affect cell response external stimuli. We have demonstrated miR-29b enhanced etoposide toxicity HeLa line by modulating this ratio isoforms. However, it not known whether the described miR-29 effect common various cancer types or even opposite effect. This...

Ischemic postconditioning and remote conditioning are potentially useful tools for protecting ischemic myocardium. This study tested the hypothesis that 2,3-dehydrosilybin (DHS), a flavonolignan component of Silybum marianum, could attenuate cardiomyocyte damage following hypoxia/reoxygenation by decreasing generation reactive oxygen species (ROS). After 5-6 days cell culture in normoxic conditions rat neonatal cardiomyocytes were divided into four groups. Control group (9 h at conditions),...

The development of new methods and strategies for the investigation membrane proteins is limited by poor solubility these in an aqueous environment hindered a number other problems linked to instability outside lipid bilayers. Therefore, current research focuses on analysis incorporated into model membrane, most frequently liposomes. In this work, we introduce electrochemical methodology transmembrane reconstituted liposomal system. proposed analytical approach based proteoliposomal sample...

The uncoupling protein is one of a family mitochondrial transport proteins involved in energy metabolism. It dissipates oxidative to generate heat, either by catalyzing proton directly or fatty acid anion transport, thus enabling acids act as cycling protonophores. This process tightly regulated purine nucleotides. We have expressed yeast and examined its activity after reconstitution into proteoliposomes. A directed change Arg276 Leu Gln completely abolished nucleotide inhibition...