A common feature of neuronal nicotinic acetylcholine receptors (nAChRs) is that they conduct inward current at negative membrane potentials but little outward current at positive membrane potentials, a property referred to as inward rectification. Physiologically, inward rectification serves important functions, and the main goal of our study was to investigate the mechanisms underlying the rec...

Molecular mechanics calculations of the binding of spermine to a number of solvated DNA helices have led to the development of a new model for spermine complexation. The structural details of the complexes formed with d(GCGCGCGCGC)2 and d(ATATATATAT)2 decamers allowed a rationalization of the observed experimental differences for binding to these two helices. For d(ATATATATAT)2 it was concluded...

proteomics concerns itself with the characterization and function of all cellular proteins, the ultimate determinants of cellular function. mass spectrometry has emerged as the preferred method for in-depth characterization of the protein components of biological systems. using mass spectrometry, key insights into the composition, regulation and function of molecular complexes and pathways have...

Activation of the caspase proteases represents a central point in apoptosis. The requirement for spermine for the processes leading to caspase activation has been studied in transformed embryonic fibroblasts obtained from gyro (Gy) mutant male mice. These cells lack spermine synthase activity and thus provide a valuable model to study the role of spermine in cell processes. Gy fibroblasts do no...

Cationic polymeric nanoparticles have great potential for developing drug delivery systemswith limited side effects for tumor medication. The goal of this research is investigation ofcationic dextran-spermine polymer (DS) efficacy for improvement of hydrophilic drug deliveryto negatively charged cancerous cells. Capecitabine (as a hydrophilic antineoplastic drug) wasloaded into the magnetic dex...

Recent pharmacological studies have led to the hypothesis that aminoglycoside-induced ototoxicity is an excitotoxic process mediated, at least in part, by a polyamine-like modulation of N-methyl-D-aspartate (NMDA) receptors. To explore this hypothesis, we compared the effects of several aminoglycosides (neomycin B, kanamycin A, streptomycin, and dihydrostreptomycin) with spermine on recombinant...

Our data suggest a novel mechanism whereby pathological-length polyglutamine (polyQ) proteins promote the spermine synthetic pathway, increasing polyQ-aggregation and cell death. As detected in a cell-free turbidity assay, spermine promotes aggregation of thio-polyQ62 in a dose-dependent manner. Using a stable neuronal cell line expressing pathological-length [polyQ57-yellow fluorescent protein...

dcAdoMet (decarboxylated S-adenosylmethionine) is an essential intermediate in the synthesis of polyamines. Its content is normally very low, amounting to less than 5% of that of S-adenosylmethionine itself. It was found that in mice lacking spermine synthase there was a large increase in dcAdoMet and that overexpression of spermine synthase reduced the amount of this nucleoside. There was also...

Vitamin B12-dependent methionine synthase is an important enzyme for sulphur amino acid, folate polyamine metabolism, S-adenosylmethionine metabolism and also in the methylation pathway of DNA, RNA, proteins and lipids. Consequently, studies aiming at exploring the control and regulation of methionine synthase are of particular interest. Here we report the modulation of enzyme activity in vitro...

Polyamine synthesis and accumulation was studied in several species of developing sea urchins. Most striking is the presence in the gametes of a large amount of spermine, with low amounts of putrescine and spermidine. This contrasts with the pattern of polyamines present in both micro-organisms and mammals. Micro-organisms contain mainly putrescine and spermidine and adult mammalian tissues usu...