title: Oxygen consumption rates and oxygen concentration in molt-4 cells and their mtDNA depleted (rho0) mutants.
abstract: Respiratory deficient cell lines are being increasingly used to elucidate the role of mitochondria and to understand the pathophysiology of mitochondrial genetic disease. We have investigated the oxygen consumption rates and oxygen concentration in wild-type (WT) and mitochondrial DNA (mtDNA) depleted (rho(0)) Molt-4 cells. Wild-type Molt-4 cells have moderate oxygen consumption rates, which were significantly reduced in the rho(0) cells. PCMB (p-chloromercurobenzoate) inhibited the oxygen consumption rates in both WT and rho(0) cells, whereas potassium cyanide decreased the oxygen consumption rates only in WT Molt-4 cells. Menadione sodium bisulfite (MSB) increased the oxygen consumption rates in both cell lines, whereas CCCP (carbonyl cyanide m-chlorophenylhydrazone) stimulated the oxygen consumption rates only in WT Molt-4 cells. Superoxide radical adducts were observed in both WT and rho(0) cells when stimulated with MSB. The formation of this adduct was inhibited by PCMB but not by potassium cyanide. These results suggest that the reactive oxygen species (ROS) induced by MSB were at least in part produced via a mitochondrial independent pathway. An oxygen gradient between the extra- and intracellular compartments was observed in WT Molt-4 cells, which further increased when cells were stimulated by CCCP and MSB. The results are consistent with our earlier findings suggesting that such oxygen gradients may be a general phenomenon found in most or all cell systems under appropriate conditions.
authors.affiliation: EPR Center, Department of Diagnostic Radiology, Dartmouth Medical School, Hanover, New Hampshire 03755, USA.
authors.forename: Jiangang
authors.initials: J
authors.lastname: Shen
authors.forename: Nadeem
authors.initials: N
authors.lastname: Khan
authors.forename: Lionel D
authors.initials: LD
authors.lastname: Lewis
authors.forename: Ray
authors.initials: R
authors.lastname: Armand
authors.forename: Oleg
authors.initials: O
authors.lastname: Grinberg
authors.forename: Eugene
authors.initials: E
authors.lastname: Demidenko
authors.forename: Harold
authors.initials: H
authors.lastname: Swartz
mesh_terms: D001565:Benzoates / Q000494:pharmacology; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D019069:Cell Respiration / Q000187:drug effects / Q000502:physiology*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D005110:Extracellular Space / Q000378:metabolism; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism; D007938:Leukemia / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000032:analysis / Q000378:metabolism*; D010101:Oxygen Consumption; D011190:Potassium Cyanide / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D019097:Spin Trapping; D013388:Succinimides / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D020245:p-Chloromercuribenzoic Acid / Q000494:pharmacology
chemical_list: D001565:Benzoates; C467959:Methyl 2-((succinimidooxy)carbonyl)benzoate; D017382:Reactive Oxygen Species; D013388:Succinimides; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D020245:p-Chloromercuribenzoic Acid; D011190:Potassium Cyanide; D010100:Oxygen