Dihydrorhodamine (DHR) 123 is a fluorophore commonly used for measuring reactive oxygen species (ROS), often after exposing cells to ultraviolet (UV) irradiation or oxidative burst inducers such as Phorbol 12-myristate 13-acetate (PMA). However, the negative effects of UV irradiation on oxidation of DHR123 itself to green fluorescence rhodamine (R) 123 under different experimental conditions (e...

Neurotrophins such as nerve growth factor (NGF) regulate neuronal survival during development and are neuroprotective in certain models of injury to both the peripheral and the central nervous system. Although many effects of neurotrophins involve long-term changes in gene expression, several recent reports have focused on rapid effects of neurotrophins that do not involve synthesis of new gene...

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 ...

Cerebral endothelial cells in the rat, pig, and, most recently, human have been shown to express several types of receptors specific for glutamate. High levels of glutamate disrupt the cerebral endothelial barrier via activation of N-methyl-d-aspartate (NMDA) receptors. We have previously suggested that this glutamate-induced barrier dysfunction was oxidant dependent. Here, we provide evidence ...

The p53 tumour suppressor protein has a crucial role in controlling cell cycle and apoptosis in human cells and its inactivation by selective point mutations is associated with human cancers. Here we show that overexpression of the human wild-type (wt) p53 in Saccharomyces cerevisiae completely inhibits yeast growth under minimal media conditions. In contrast, the R248W 'hot spot' p53 mutant (o...

Peroxynitrite, a potent cytotoxic oxidant formed by the reaction of nitric oxide (NO) with the superoxide anion, was recently proposed to play a major pathogenic role in the inflammatory process. Here we have investigated the effects of endogenous melatonin, a known scavenger of peroxynitrite, in rats subjected to carrageenan-induced pleurisy. Endogenous melatonin was depleted in rats maintaine...

Two-photon fluorescence imaging is used to detect UV-induced reactive oxygen species (ROS) in ex vivo human skin in this study. ROS (potentially H202, singlet oxygen or peroxynitrite [or all]) are detected after reaction with nonfluorescent dihydrorhodamine-123 (DHR) and the consequent formation of fluorescent rhodamine-123 (R123). The cellular regions at each epidermal stratum that generate RO...

The self-prepared pectin hydroxamic acid has been reported to have antioxidant activities [Yang, S. S., Cheng, K. D., Lin, Y. S., Liu, Y. W., & Hou, W. C. (2004). Pectin hydroxamic acids exhibit antioxidant activities in vitro. Journal of Agricultural and Food Chemistry, 52, 4270-4273]. In this study, the galacturonic acid (GalA), the monomer unit of the pectin polymer, was esterified with acid...