Arsenic trioxide (ATO) affects many biological functions such as cell proliferation, apoptosis, differentiation and angiogenesis in various cells. We investigated the in vitro effects of ATO as a reactive oxygen species (ROS) generator or a glutathione (GSH) depletor on apoptosis in HeLa cells. ATO decreased the viability of HeLa cells in a dose-dependent manner with an IC50 of approximately 5-...

Nitric oxide (NO) and its derivatives (reactive nitrogen species) have multiple effects on mitochondria that impact on cell physiology and cell death. Mitochondria may produce and consume NO and NO stimulates mitochondrial biogenesis, apparently via cGMP upregulation of transcriptional factors. NO inhibits mitochondrial respiration via: (A) an acute and reversible inhibition of cytochrome oxida...

Tetrahydrobiopterin (BH4) is an essential cofactor for the normal enzymatic function of endothelial NO synthase (eNOS) to produce NO, because it is involved in the catalytic process of L-arginine oxidation. Insufficient BH4 availability impairs this process, and the free radical superoxide anion (O2 ) is released rather than NO, a condition termed “eNOS uncoupling.”1 BH4, eNOS, and NO levels ph...

Initial attempts to grow N2-fixing Derxia gummosa autotrophically on H2, C 0 2 , O2 and N2 in a closed system yielded variable results. Poor growth was found to be due to rapid O2 depletion and the requirement for an agar surface. In a closed system, C2H2 reduction assays could not be carried out due to complete consumption of H2. Hence a flow-through culturing technique was developed to supply...

Cyanobacteria, algae, and plants oxidize water to the O2 we breathe, and consume CO2 during the synthesis of biomass. Although these vital processes are functionally and structurally well separated in photosynthetic organisms, there is a long-debated role for CO2/ in water oxidation. Using membrane-inlet mass spectrometry we demonstrate that acts as a mobile proton acceptor that helps to transp...

Antimycin A (AMA) inhibits the growth of various cells via stimulating oxidative stress-mediated death. However, little is known about the anti-growth effect of AMA on normal primary lung cells. Here, we investigated the effects of AMA on cell growth inhibition and death in human pulmonary fibroblast (HPF) cells in relation to reactive oxygen species (ROS) and glutathione (GSH) levels. AMA inhi...

Nitrous oxide (N2O) is an environmental pollutant that has a significant greenhouse effect and contributes to the depletion of ozone layer. To address issues caused by N2O, direct catalytic decomposition N2O N2 O2 been demonstrated as one most efficient methods for its removal. Various metals, particularly noble including Rh, Ru, Pd, Pt, Au, Ir, have widely used investigated catalysts facilitat...

Arsenic trioxide (ATO; As2O3) induces apoptotic cell death in various cancer cells including lung cancer via the induction of reactive oxygen species (ROS). However, little is known about the toxicological effects of ATO on normal primary lung cells. Here, we investigated the effects of N-acetyl cysteine (NAC) and vitamin C (well-known antioxidant...

The physical law of diffusion imposes O2 concentration gradients from the plasma membrane to the center of the cell. The present study was undertaken to determine how such intracellular radial gradients of O2 affect the fate of isolated single cardiomyocytes. In single rat cardiomyocytes, mitochondrial respiration was moderately elevated by an oxidative phosphorylation uncoupler to augment the ...

The dynamics of O2 depletion in exceptional dinoflagellate blooms, often referred to as red tides or harmful algal blooms (HABs), was investigated in St. Helena Bay in the southern Benguela upwelling system in 2013. The transition to bloom decay and anoxia was examined through determination of O2-based productivity and respiration rates. Changes in O2 concentrations in relation to bloom metabol...