Electrostatic interaction between merocyanine 540 and liposomal and mitochondrial membranes

Summary The fluorescence of merocyanine 540 (MC) in liposomal and mitochondrial suspensions was measured under various conditions. Under a given condition, both the amount of dye bound to the membrane and the zeta potential were determined simultaneously. It was found that the fluorescence intensity was proportional to the amount of bound dye and correlated with the zeta potential of particles. The fluorescence intensity was represented quantitatively in terms of the Langmuir adsorption isotherm, when the electrostatic interaction acting between MC and membrane surface was properly taken into account. It was concluded that the changes in MC fluorescence in the liposomal and mitochondrial suspensions are mainly attributed to the changes in the surface potential of the membranes.     

Studies of Viable T4 Bacteriophage Containing Cytosine-substituted DNA (T4dC Phage). III. Advantage of T4dC DNA as Substrate for Assay of Restriction Endonucleases

Cytosine-substituted phage T4 DNA (T4dC DNA) was demonstrated to be a splendid substrate for the assay of restriction endonucleases by agarose gel electrophoresis. For preparing those which cleave lambda phage DNA at few sites, T4dC DNA having appreciable number of cleavage sites was especially useful. As typical examples SalI and XbaI restriction endonucleases were chosen and an advantage of T4dC DNA for the enzyme unit determination was described. Screening of new restriction endonucleases from Streptomyces strains was facilitated by using T4dC DNA as a substrate for the assay.