Showing papers on "Polyamine binding published in 2016"

Effect of N1-dansylspermine and Ro25,6981 on locomotor activity in naive mice and in the reserpinized mouse model of Parkinson's disease.

Abstract: The effect of N1-dansylspermine, a polyamine analogue and competitive polyamine antagonist, and Ro25,6981, a noncompetitive polyamine antagonist with good affinity and selectivity for the GluN2B subunit, on locomotor activity in naive mice was investigated. Furthermore, the ability of the polyamine antagonists to reverse reserpine-induced hypokinesia was assessed, 24 h after injection of a catecholamine-depleting dose of reserpine (5 mg/kg, subcutaneous), to investigate the therapeutic potential of polyamine antagonists in Parkinson's disease. N1-dansylspermine significantly decreased locomotor activity in naive animals (P<0.001) but caused a mild, but significant increase in locomotor activity in reserpinized mice at the highest dose tested (P<0.05). Ro25,6981 significantly stimulated locomotor activity in naive animals (P<0.001) and had a slight significant stimulatory effect on reserpine-induced hypokinesia (P=0.05). N1-dansylspermine and Ro25,6981 had opposite effects on locomotor activity in naive mice, but both had a mild antiparkinsonian effect in the reserpine model. These findings suggest that antagonism of the polyamine binding site on the GluN2B subunit can reduce hypokinesia, albeit to a limited extent.

Characterization of the NspS-MbaA signaling system controlling biofilm formation from polyamine input to phenotypic output

Abstract: Biofilm formation plays a critical role in the infectious cycle of the bacterial pathogen, Vibrio cholerae. The polyamine, norspermidine, has a positive influence on biofilm formation while spermidine has the opposite effect. These influences occur through a signaling system comprised of the periplasmic polyamine binding protein, NspS, and the transmembrane phosphodiesterase, MbaA. In the absence of NspS, MbaA acts as a phosphodiesterase cleaving the pro-biofilm second messenger, cyclic di-GMP, indicating that NspS may interact with and inhibit phosphodiesterase activity and biofilm repression by MbaA. In this study, I have shown that several nspS ligand-binding pocket mutants have altered sensitivity to norspermidine and spermidine as indicated by vps transcription and biofilm assays. I have also shown using thermal shift assays that these mutants are capable of binding both polyamines. LC-MS/MS analyses indicate that the NspS-MbaA signaling pathway is a high specificity c-di-GMP signaling system. Additionally, a system for reproducible demonstration of the NspS-MbaA interaction was developed which may subsequently be used in future experiments to study the NspS and MbaA interaction. Altogether, this study provides a thorough investigation of the steps involved in polyamine signal input to phenotypic output for a novel polyamine responsive signaling system controlling V. cholerae biofilm formation.