Hydrogen peroxide as an effective disinfectant for Pasteurella multocida.

Pasteurella multocida (P. multocida) infections vary widely, from local infections resulting from animal bites and scratches to general infections. As of yet, no vaccine against P. multocida has been developed, and the most effective way to prevent pathogenic transmission is to clean the host environment using disinfectants. In this study, we identified which disinfectants most effectively inhibited environmental isolates of P. multocida. Three readily available disinfectants were compared: 3% hydrogen peroxide (HP), 70% isopropyl alcohol, and synthetic phenol. In suspension tests and zone inhibition tests, 3% HP was the most promising disinfectant against P. multocida.

Single channel function of inositol 1,4,5-trisphosphate receptor type-1 and -2 isoform domain-swap chimeras.

The InsP3R proteins have three recognized domains, the InsP3-binding, regulatory/coupling, and channel domains (Mignery, G.A., and T.C. Südhof. 1990. EMBO J. 9:3893-3898). The InsP3 binding domain and the channel-forming domain are at opposite ends of the protein. Ligand regulation of the channel must involve communication between these different regions of the protein. This communication likely involves the interceding sequence (i.e., the regulatory/coupling domain). The single channel functional attributes of the full-length recombinant type-1, -2, and -3 InsP3R channels have been defined. Here, two type-1/type-2 InsP3R regulatory/coupling domain chimeras were created and their single channel function defined. One chimera (1-2-1) contained the type-2 regulatory/coupling domain in a type-1 backbone. The other chimera (2-1-2) contained the type-1 regulatory/coupling domain in a type-2 backbone. These chimeric proteins were expressed in COS cells, isolated, and then reconstituted in proteoliposomes. The proteoliposomes were incorporated into artificial planar lipid bilayers and the single-channel function of the chimeras defined. The chimeras had permeation properties like that of wild-type channels. The ligand regulatory properties of the chimeras were altered. The InsP3 and Ca2+ regulation had some unique features but also had features in common with wild-type channels. These results suggest that different independent structural determinants govern InsP3R permeation and ligand regulation. It also suggests that ligand regulation is a multideterminant process that involves several different regions of the protein. This study also demonstrates that a chimera approach can be applied to define InsP3R structure-function.

Glutathione potentiates cloned rat brain large conductance Ca(2+)-activated K(+) channels (rSlo).

We have investigated the modulation of a cloned rat brain alpha-subunit of large conductance Ca(2+)-activated K(+) channels (rSlo K(+) channels) by glutathione (GSH), a physiological sulfhydryl-specific reducing reagent. The application of GSH to the intracellular side of excised inside-out macroscopic patches of rslo-transfected HEK293 cells reversibly activated the currents. The activation rate constants of the current were increased while the deactivation rate constants were decreased by GSH at all voltages tested without any change in the voltage dependence of the rate constants. GSH induced a leftward shift of the steady state conductance-voltage relationship curve of the current with no change in the slope of the curve. These results suggest that modulation by GSH may constitute an important regulatory mechanism of neuronal large conductance Ca(2+)-activated K(+) channels.