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Journal of Biomedical Optics

Mitochondrial respiratory complex I probed by delayed luminescence spectroscopy
Author(s): Irina Baran; Diana N. Ionescue; Simona S. Privitera; Agata A. Scordino; Maria M. Mocanu; Francesco F. Musumeci; Rosaria Grasso; Marisa Gulino; Adrian Iftime; Ioana T. Tofolean; Alexandru Garaiman; Alexandru Goicea; Ruxandra Irimia; Alexandru Dimancea; Constanta Ganea
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Paper Abstract

The role of mitochondrial complex I in ultraweak photon-induced delayed photon emission [delayed luminescence (DL)] of human leukemia Jurkat T cells was probed by using complex I targeting agents like rotenone, menadione, and quercetin. Rotenone, a complex I-specific inhibitor, dose-dependently increased the mitochondrial level of reduced nicotinamide adenine dinucleotide (NADH), decreased clonogenic survival, and induced apoptosis. A strong correlation was found between the mitochondrial levels of NADH and oxidized flavin mononucleotide (FMNox ) in rotenone-, menadione- and quercetin-treated cells. Rotenone enhanced DL dose-dependently, whereas quercetin and menadione inhibited DL as well as NADH or FMNox . Collectively, the data suggest that DL of Jurkat cells originates mainly from mitochondrial complex I, which functions predominantly as a dimer and less frequently as a tetramer. In individual monomers, both pairs of pyridine nucleotide (NADH/reduced nicotinamide adenine dinucleotide phosphate) sites and flavin (FMN-a/FMN-b) sites appear to bind cooperatively their specific ligands. Enhancement of delayed red-light emission by rotenone suggests that the mean time for one-electron reduction of ubiquinone or FMN-a by the terminal Fe/S center (N2) is 20 or 284 μs, respectively. All these findings suggest that DL spectroscopy could be used as a reliable, sensitive, and robust technique to probe electron flow within complex I in situ.

Paper Details

Date Published: 23 December 2013
PDF: 22 pages
J. Biomed. Opt. 18(12) 127006 doi: 10.1117/1.JBO.18.12.127006
Published in: Journal of Biomedical Optics Volume 18, Issue 12
Show Author Affiliations
Irina Baran, "Carol Davila" Univ. of Medicine and Pharmacy (Romania)
Diana N. Ionescue, "Carol Davila" Univ. of Medicine and Pharmacy (Romania)
Simona S. Privitera, Istituto Nazionale di Fisica Nucleare (Italy)
Agata A. Scordino, Istituto Nazionale di Fisica Nucleare (Italy)
Maria M. Mocanu, "Carol Davila" Univ. of Medicine and Pharmacy (Romania)
Francesco F. Musumeci, Univ. degli Studi di Catania (Italy)
Rosaria Grasso, Istituto Nazionale di Fisica Nucleare (Italy)
Marisa Gulino, Istituto Nazionale di Fisica Nucleare (Italy)
Adrian Iftime, "Carol Davila" Univ. of Medicine and Pharmacy (Romania)
Ioana T. Tofolean, "Carol Davila" Univ. of Medicine and Pharmacy (Romania)
Alexandru Garaiman, "Carol Davila" Univ. of Medicine and Pharmacy (Romania)
Alexandru Goicea, "Carol Davila" Univ. of Medicine and Pharmacy (Romania)
Ruxandra Irimia, "Carol Davila" Univ. of Medicine and Pharmacy (Romania)
Alexandru Dimancea, "Carol Davila" Univ. of Medicine and Pharmacy (Romania)
Constanta Ganea, "Carol Davila" Univ. of Medicine and Pharmacy (Romania)


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