In a preliminary experiment, the inclusion of vitamin K1 (K1) at a dietary level of 0.1 mg/kg was as effective as 1 or 2 mg/kg in reducing plasma prothrombin time (PT). To obtain an estimate of the dietary K1 requirement and to compare the biopotency of different vitamin K sources for poults, three additional experiments were conducted. In Experiment 1, an incomplete factorial arrangement of tr...

We constructed and characterized a Xanthomonas campestris pv. phaseoli oxyR mutant. The mutant was hypersensitive to H2O2 and menadione killing and had reduced aerobic plating efficiency. The oxidants' induction of the catalase and ahpC genes was also abolished in the mutant. Analysis of the adaptive responses showed that hydrogen peroxide-induced protection against hydrogen peroxide was lost, ...

The non-cytotoxic concentration (20 microM) of menadione (2-methyl-1,4-naphthoquinone), after 1 h of incubation, leads to loss of the activity of rhodanese by 33%, 3-mercaptopyruvate sulfurtransferase by 20%, as well as the level of sulfane sulfur by about 23% and glutathione by 12%, in the culture of U373 cells, in comparison with the control culture. Reactive oxygen species generated by menad...

Firstand second-order derivative spectrophotometric methods for the quantitative determination by converting menadione sodium bisulphite (MSB) to menadione (M ) with sodium carbonate were developed and validated in pharmaceutical preparation. The quantitative determination of MSB was carried out by using wavelengths 350 nm (for first-order; 1D) and 355 nm (for second-order; 2D) with the lineari...

Three echinoderms, a crustacean, a mollusc and a coelenterate were injected with either [2-14C]mevalonate and unlabelled menadione (2-methyl-1,4-naphthaquinone) or 2-[14C]methyl-1,4-naphthaquinone. In each case the label was incorporated into menaquinone-4.[2-14C]Mevalonate was incorporated into menaquinone-4 in the crab (Carcinus maenas) only in the presence of menadione, the organism presumab...

The non-cytotoxic concentration (20 μM) of menadione (2-methyl-1,4-naphthoquinone), after 1 h of incubation, leads to loss of the activity of rhodanese by 33%, 3-mercaptopyruvate sulfurtransferase by 20%, as well as the level of sulfane sulfur by about 23% and glutathione by 12%, in the culture of U373 cells, in comparison with the control culture. Reactive oxygen species generated by menadione...