Search results for "Membrane Transport Proteins"
showing 10 items of 145 documents
Therapeutic-like properties of a dopamine uptake inhibitor in animal models of amphetamine addiction.
2010
N-substituted benztropine (BZT) analogs are molecules that display high affinity for the dopamine transporter (DAT), therapeutic-like effects in animal models of cocaine abuse, and psychopharmacological characteristics consistent with those of a substitute medication for cocaine addiction. Since amphetamine (Amph) and cocaine share mechanisms of action at the DAT, we evaluated the effectiveness of a BZT analog in animal models of Amph addiction. We tested in mice and rats the effects of the BZT derivative, 3α-[bis(4-fluorophenyl)methoxy]-tropane (AHN-1055), on Amph-induced conditioned place preference (CPP), locomotor activity, sensitization, self-administration and ΔFosB accumulation in th…
Transcriptional expression of selected genes associated with excretion of carboxylic acids from aci mutants of Saccharomyces cerevisiae
2013
Introduction: Saccharomyces cerevisiae is an excellent model organism for studies of transcriptional regulation of metabolic processes in other eukaryotic cells including human cells. Cellular acid-base balance can be disturbed in pathologic situations such as renal acidosis or cancer. The extracellular pH of malignant solid tumors is acidic in the range of 6.5-6.9. EG07 and EG37 aci mutants of Saccharomyces cerevisiae excessively excrete carboxylic acids to glucose-containing media or distilled water. The excreted acids are Krebs and/or glyoxylate cycle intermediates. The genes restoring the wild-type phenotype have function that does not easily explain theAci phenotype.Material/Methods: I…
Redox signaling (cross-talk) from and to mitochondria involves mitochondrial pores and reactive oxygen species
2010
This review highlights the important role of redox signaling between mitochondria and NADPH oxidases. Besides the definition and general importance of redox signaling, the cross-talk between mitochondrial and Nox-derived reactive oxygen species (ROS) is discussed on the basis of 4 different examples. In the first model, angiotensin-II is discussed as a trigger for NADPH oxidase activation with subsequent ROS-dependent opening of mitochondrial ATP-sensitive potassium channels leading to depolarization of mitochondrial membrane potential followed by mitochondrial ROS formation and respiratory dysfunction. This concept was supported by observations that ethidium bromide-induced mitochondrial d…
Nitroglycerine causes mitochondrial reactive oxygen species production: In vitro mechanistic insights
2007
Background Nitroglycerine (GTN) is an organic nitrate that has been used for more than 100 years. Despite its widespread clinical use, several aspects of the pharmacology of GTN remain elusive. In a recent study, the authors of the present study showed that GTN causes opening of the mitochondrial permeability transition pore (mPTP) and mitochondrial production of reactive oxygen species (ROS). Objective In the present study, it was tested whether GTN-induced ROS production depends on mitochondrial potassium ATP-dependent channel or mPTP opening, and/or GTN biotransformation. Methods and results Isolated rat heart mitochondria were incubated with succinate (a substrate for complex II) and GT…
When two turn into one: evolution of membrane transporters from half modules
2014
Abstract The recently increasing number of atomic structures for active transporters has not only revealed strong conservation in the architecture of sequence-unrelated transporter families, but also identified a unifying element called the ‘inverted repeat topology,’ which is found in nearly all transporter folds to date. Indeed, most membrane transporters consist of two or more domains with similar structure, so-called repeats. It is tempting to speculate that transporters have evolved by duplication of one repeat followed by gene fusion and modification events. An intriguing question is, whether recent genes encoding such a ‘half-transporter’ still exist as independent folding units. Alt…
Coordinate overexpression of two RND efflux systems, ParXY and TtgABC , is responsible for multidrug resistance in Pseudomonas putida
2020
Resistance Nodulation cell Division (RND) efflux pumps are known to contribute to the tolerance of Pseudomonas putida to aromatic hydrocarbons, but their role in antibiotic resistance has not been fully elucidated. In this study, two types of single-step multidrug-resistant (MDR) mutants were selected in vitro from reference strain KT2440. Mutants of the first type were more resistant to fluoroquinolones and β-lactams except imipenem, and overproduced the efflux system TtgABC as a result of mutations occurring in regulator TtgR. In addition to TtgABC, mutants of the second type such as HPG-5 were found to upregulate a novel RND pump, dubbed ParXY/TtgC, which accommodates cefepim, fluoroquin…
Distribution of the vesicular acetylcholine transporter (VAChT) in the central and peripheral nervous systems of the rat.
1994
Expression of the acetylcholine biosynthetic enzyme choline acetyltransferase (ChAT), the vesicular acetylcholine transporter (VAChT), and the high-affinity plasma membrane choline transporter uniquely defines the cholinergic phenotype in the mammalian central (CNS) and peripheral (PNS) nervous systems. The distribution of cells expressing the messenger RNA encoding the recently cloned VAChT in the rat CNS and PNS is described here. The pattern of expression of VAChT mRNA is consistent with anatomical, pharmacological, and histochemical information on the distribution of functional cholinergic neurons in the brain and peripheral tissues of the rat. VAChT mRNA-containing cells are present in…
New methods to improve the safety assessment of cryopreserved ovarian tissue for fertility preservation in breast cancer patients
2015
Objective To develop a novel molecular panel of markers to detect breast cancer (BC) disseminated malignant cells in ovarian tissue, and to improve the safety of ovarian tissue transplantation. Design Experimental study. Setting University hospital. Patient(s) Ten ovarian biopsies from healthy patients, 13 biopsies with diagnosed BC metastasis, and 4 biopsies from primary BC tumor for designing a diagnostic panel of BC cell contamination; 60 ovarian biopsies from BC patients undergoing fertility preservation for validating the panel. Animal(s) Female nude mice. Intervention(s) A novel panel for BC malignant cell detection by reverse-transcription polymerase chain reaction (RT-PCR), inmmunoh…
The stability and functional properties of proteoliposomes mixed with dextran derivatives bearing hydrophobic anchor groups
1992
Liposomes composed of Escherichia coli phospholipid were coated with polysaccharides bearing hydrophobic palmitoyl anchors. The effect on the stability of liposomes without or with integral membrane proteins was investigated. A high concentration of hydrophobized dextrans protected the liposomes against detergent degradation, decreased the fluidity of the membranes, prevented fusion of the liposomes and enhanced their stability. Proteoliposomes containing beef heart cytochrome-c oxidase and the lactose transport carrier of E. coli were similarly affected by coating with the dextrans. Under these conditions both membrane proteins were still active. Long-term stability of the coated liposomes…
The Arabidopsis COPT6 Transport Protein Functions in Copper Distribution Under Copper-Deficient Conditions
2013
Copper (Cu), an essential redox active cofactor, participates in fundamental biological processes, but it becomes highly cytotoxic when present in excess. Therefore, living organisms have established suitable mechanisms to balance cellular and systemic Cu levels. An important strategy to maintain Cu homeostasis consists of regulating uptake and mobilization via the conserved family of CTR/COPT Cu transport proteins. In the model plant Arabidopsis thaliana, COPT1 protein mediates root Cu acquisition, whereas COPT5 protein functions in Cu mobilization from intracellular storage organelles. The function of these transporters becomes critical when environmental Cu bioavailability diminishes. Ho…