Acridine orange as a fluorescent probe for lysosomal proton pump.

Lysosomal proton pump activity: supravital cell staining with acridine orange differentiates leukocyte subpopulations.

Prelysosomal acidic vacuoles in Dictyostelium discoideum

We have examined the ameba Dictyostelium discoideum for evidence of a discrete, prelysosomal, acidic receiving compartment in endocytosis. We observed in the cytoplasm abundant round vacuoles with diameters up to 2 microns that concentrated acridine orange by a process inhibited by 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl). They were therefore taken to be acidic. The vacuoles were observ...

Interference with the endosomal acidification by a monoclonal antibody directed toward the 116 (100)-kD subunit of the vacuolar type proton pump

A monoclonal antibody (OSW2) was prepared by using human osteosarcoma cells. OSW2 was found to be directed toward the 116 (also called 100)- kD protein that uniquely associates to the vacuolar-type proton pump. The antibody specifically localized acidic membrane compartments that could be visualized with acridine orange in many types of human cells. It also reacted with the surface and was inte...

Reconstitution of the lysosomal proton pump.

Lysosomal membrane proteins solubilized with octyl beta-D-glucopyranoside were reconstituted into proteoliposomes using acetone/ether-washed phospholipids from Escherichia coli. Assays of the quenching of acridine orange fluorescence showed that addition of both ATP and valinomycin to K+-loaded proteoliposomes led to the formation of a pH gradient that was acidic inside. ATP-driven acidificatio...

Effect of temperature on the plasma membrane and tonoplast ATPases of barley roots : comparison of results obtained with acridine orange and quinacrine.

The effect of temperature on the rate of proton transport and ATP hydrolysis by plasma membrane (PM) and tonoplast (TN) ATPases from barley (Hordeum vulgare L. cv CM 72) roots were compared. Rates of proton transport were estimated using the fluorescent amine dyes quinacrine and acridine orange. The ratio between rate of transport and ATP hydrolysis was found to depend on the dye, the temperatu...