The default growth pattern of primary roots of land plants is directed by gravity. However, roots possess the ability to sense and respond directionally to other chemical and physical stimuli, separately and in combination. Therefore, these root tropic responses must be antagonistic to gravitropism. The role of reactive oxygen species (ROS) in gravitropism of maize and Arabidopsis (Arabidopsis ...

Rabbit abdominal aortic smooth muscle cells (SMC) were stably transfected with the cDNA of porcine phospholipid hydroperoxide glutathione peroxidase (PHGPx) by means of a retroviral gene transfer technique, to create a model for studying cellular processes relevant to atherogenesis. The transfected cells (SMC/PHGPx) had approximately 4-fold higher PHGPx activity when cultured in the presence of...

Conflicting data have been reported about the impact of repeated HBO2 exposure on the production of superoxide radicals during the neutrophil respiratory burst (RB) and on phagocytosis. In this study we wanted to see if exposure to hyperoxia would affect human neutrophil RB and phagocytosis. Short- and long-term effects after single or repetitive HBO2 exposure of 2.5 atmospheres absolute over a...

HE (hydroethidine), a widely used fluorescent dye for detecting intracellular superoxide, undergoes specific oxidation and hydroxylation reactions. The reaction between HE and O2•- (superoxide radical) yields a diagnostic marker product, 2-hydroxyethidium. This is contrary to the popular notion that O2•- oxidizes HE to form ethidium. HE, however, undergoes a non-specific oxidation to form ethid...

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) produced by epithelial and inflammatory cells are key mediators of the chronic airway inflammation of asthma. Low L-arginine levels can result in the uncoupling of nitric oxide synthase (NOS) leading to production of both ROS and RNS. Asymmetric dimethylarginine (ADMA) is a competitive endogenous inhibitor of all NOS isoforms and...

Radiotracers are widely used to track molecular processes, both in vitro and in vivo, with high sensitivity and specificity. However, most radionuclide detection methods have spatial resolution inadequate for single-cell analysis. A few existing methods can extract single-cell information from radioactive decays, but the stochastic nature of the process precludes high-throughput measurement (an...

OBJECTIVE Redox imbalance contributes to bone fragility. We have evaluated the in vivo role of nuclear factor erythroid derived 2-related factor-2 (Nrf2), an important regulator of cellular responses to oxidative stress, in bone metabolism using a model of postmenopausal osteoporosis. METHODS Ovariectomy was performed in both wild-type and mice deficient in Nrf2 (Nrf2(-/-)). Bone microarchite...

OBJECTIVE To understand the mechanism by which oxidants are linked to insulin resistance, bovine aortic endothelial cells were exposed to oxidized low-density lipoproteins (oxLDL) or peroxynitrite. METHODS AND RESULTS OxLDL transiently increased phosphorylation of Erk and Akt within 5 minutes, but 60 minutes later, resulted in decreased insulin-induced Akt phosphorylation. OxLDL promoted a 2-...

It has been shown that hypercholesterolemia (HCh) exaggerates the microvascular dysfunction that is elicited by ischemia and reperfusion (I/R). The objective of this study was to determine whether oxidants contribute to the exaggerated inflammatory responses and enhanced albumin leakage observed in HCh rat mesenteric venules exposed to I/R (10 minutes of ischemia and 30 minutes of reperfusion)....

Reactive oxygen species (ROS) production by phagocytic leukocytes is a critical factor in immunity against microorganisms. Human neonates are susceptible to overwhelming infections, for which abnormal granulocyte function may play an important role. In this study, we aimed to identify a convenient and quantitative method to measure ROS production by human granulocytes after cellular activation....