Ageladine A, a pyrrole-imidazole alkaloid from marine sponges, is a pH sensitive membrane permeable dye.
The alkaloid ageladine A, a pyrrole-imidazole alkaloid isolated from marine Agelas sponges shows fluorescence in the blue-green range during excitation with UV light with the highest absorption at 370 nm. The fluorescence of this alkaloid is pH dependent. Highest fluorescence is observed at pH 4, lowest at pH 9 with the largest fluorescence changes between pH 6 and 7. Ageladine A is brominated, which facilitates membrane permeation and therefore allows for easy staining of living cells and even whole transparent animal staining. To calculate the exact pH in solutions, cells, and tissues, the actual concentration of the alkaloid has to be known. A ratiometric measurement at the commonly used excitation wavelengths at 340/380 nm allows pH measurements in living tissues with an attenuated influence of the ageladine A concentration on calculated values. The fluorescence changes report small intracellular pH changes induced by extracellular acidification and alkalization as well as intracellular alkalization induced by ammonium chloride.
Bickmeyer
Ulf
U
Alfred-Wegener-Institut für Polar- und Meeresforschung in der Helmholtz-Gemeinschaft, Biologische Anstalt Helgoland, Kurpromenade 201, D-27498 Helgoland, Germany. Ulf.Bickmeyer@awi.de
Grube
Achim
A
Klings
Karl-Walter
KW
Köck
Matthias
M
D047230:Agelas / Q000737:chemistry*; D000470:Alkaloids / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000737:chemistry / Q000378:metabolism; D016716:PC12 Cells; D010539:Permeability; D011758:Pyrroles / Q000737:chemistry / Q000378:metabolism*; D051381:Rats
C482289:Ageladine A; D000470:Alkaloids; D005456:Fluorescent Dyes; D007093:Imidazoles; D011758:Pyrroles; C029899:imidazole