Reversible excitation light-induced enhancement of fluorescence of live mammalian mitochondria.
During continuous irradiation with near-ultraviolet light (l = 36510 nm; 16 mW/mm(2)) for 2-3 min, live mammalian cells increased reversibly the intensity of one or more peaks of their autofluorescence spectrum from an initial ('ground') level to a two- to threefold higher ('active') level. The effect is characterized by the existence of two states of quantum efficiency and a mechanism of transition that expresses a threshold and a refractory period. It appears that mitochondria are the principal sources of the rising autofluorescence intensity; however, not all mitochondria are capable of expressing it. Studying cells from various organisms that belong to various branches of the phylogenetic tree, we found the rapid increase of autofluorescence only in placental mammalian cells. We speculate that the effect may point to the ability of placental mammalian mitochondria to generate pulsating light signals.
Albrecht-Buehler
G
G
Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA.
D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D002478:Cells, Cultured; D005453:Fluorescence; D008027:Light; D008322:Mammals; D008928:Mitochondria / Q000502:physiology* / Q000528:radiation effects