Membrane permeant acetaldehyde and menadione induced the synergistic reduction of toluylene blue (TB) acting as non-membrane permeant redox indicator in yeast cell suspension. NADH and acetaldehyde also induced the synergistic TB reduction in permeabilized yeast cells and phosphate buffer, but menadione had no ability to promote TB reduction. The pre-incubation of acetaldehyde inhibited the abo...

Human erythrocytes were treated with menadione to oxidatively denature hemoglobin and release ferriprotoporphyrin IX (ferriheme, FP) intracellularly. The high affinity of FP for chloroquine was used to detect its release. After incubation for 1 hr at 37’C and pH 7.4 with 0.5 mM menadione, erythrocytes bound 14C-chloroquine with an apparent dissociation constant of 1O M. Untreated erythrocytes d...

staphylococcus aureus produces a particular morphological variant called small colony variant (scv) which is responsible for persistent subclinical infections in predisposed individuals and is usually resistant to aminoglycosides and cell wall active antibiotics. infections by scv of s. aureus are an upcoming problem due to difficulty in laboratory diagnosis and resistance to antimicrobial chem...

The cytotoxicity of menadione on hepatocytes was studied by using the substrate generation/tip collection mode of scanning electrochemical microscopy by exposing the cells to menadione and detecting the menadione-S-glutathione conjugate (thiodione) that is formed during the cellular detoxication process and is exported from the cell by an ATP-dependent pump. This efflux was electrochemically de...

Oxidative stress induced in live HeLa cells by menadione (2-methyl-1,4-napthaquinone) was studied in real time by scanning electrochemical microscopy (SECM). The hydrophobic molecule menadione diffuses through a living cell membrane where it is toxic to the cell. However, in the cell it is conjugated with glutathione to form thiodione. Thiodione is then recognized and transported across the cel...

While menadione plus NADH or menadiol is unable to promote in vitro vitamin K-dependent carboxylation in a solubilized rat liver microsomal incubation system (as does vitamin K1 hydroquinone or vitamin K1 plus NADH), addition of various monoand dithiols with the menadione produces activity. Adducts of menadione and a number of thiols have been prepared in pure form and were found to be able to ...

-Ketoglutarate (KG) is a crucial metabolite in all living organisms, as it participates in a variety of biochemical processes. We have previously shown that this keto acid is an antioxidant and plays a key role in the detoxification of reactive oxygen species (ROS). In an effort to further confirm this intriguing phenomenon, Pseudomonas fluorescens was exposed to menadione-containing media, wit...

PURPOSE To investigate the effect of rho kinase inhibitors on oxidative stress in trabecular meshwork (TM) cells. METHODS TM cells were isolated from the eyes of cynomolgus monkeys. Y-27632 and menadione were used to inhibit rho kinase and induce production of reactive oxygen species (ROS), respectively. The cynomolgus monkey array and 12,613 probes were used in DNA microarray analysis, and t...

Menadione (2-methyl-1,4-naphthoquinone) is a remarkably potent inhibitor of microsomal lipid peroxidation, effective at submicromolar concentrations. Its possible mechanism of action and the relationship between naphthoquinone structure and antioxidant activity were the topics of this investigation. In the microsomal lipid-peroxidizing system dependent on NADPH and ferric pyrophosphate, menadio...

PURPOSE The crystalline lens is a unique cellular organ that performs metabolic processes while maintaining transparency for optical functionality. Mitochondria play a role in providing cells with aerobic respiration necessary for these metabolic processes. Using menadione, a mitochondria-specific inhibitor of the quinone family, and bovine lenses in vitro, this study was undertaken to determin...