Histone inhibits the photosystem 1 activities of isolated chloroplasts. This inhibition can be prevented by prior exposure of the chloroplasts to moderate concentrations of inorganic salts. However, even very high concentrations of inorganic salts will not reverse the inhibition, nor is the inhibition reversed by washing the chloroplasts. Exogenous plastocyanin causes a partial reversal of hist...

DURING the past 3 years several methods have been proposed, and widely used, for the estimation of ascorbic acid in urine. They all depend on the reducing properties of ascorbic acid and are all non-specific. By careful limitation of conditions it is possible, with these methods, to exclude interference by a number of substances known to be present in urine and to reduce the reagents employed. ...

Most of the chemical methods which have been proposed for the estimation of ascorbic acid have been based upon the principle that, under suitable experimental conditions, ascorbic acid more or less specifically and quantitatively reduces certain colored reagents (1). The simplicity of manipulation plus the relatively close correlation between the vitamin C content of plant and animal tissues (b...

The optical sensor for "tea catechins" was built by immobilizing 2,2'-(1,4-phenylenedivinylene)bis-8-hydroxyquinoline (PBHQ) on TiO₂ nanoparticles (NPs). The sensor worked by "indophenol blue" dye formation on PBHQ-immobilized TiO₂ NPs as a result of p-aminophenol (PAP) autoxidation with dissolved O₂ at pH 10. Among quercetin, rutin, naringenin, naringin, gallic acid, caffeic acid, ferulic acid...

Bicarbonate ion, not dissolved CO(2) gas, is shown to increase 4- to 5-fold the rate of dichlorophenol indophenol reduction by isolated maize (Zea mays) chloroplasts. Glutaraldehyde fixed chloroplasts continue to exhibit bicarbonate-dependent 2,6-dichlorophenol indophenol reduction. Bicarbonate is shown to act close to the oxygen-evolving site, i.e. prior to the electron donation site of diphen...

In order to determine ammonium ion in water samples, we propose a method based on the Berthelot reaction of ammonia with 1-naphthol and dichloroisocyanurate to form an indophenol blue derivative and collection of the blue compound as an ion pair using Zephiramine on a pure polytetrafluoroethylene (PTFE)-type membrane filter. The ion pair on the filter was eluted with 5.0 mL of acetonitrile, and...

1. Carbon dioxide-bicarbonate mixtures markedly inhibited oxidation and phosphorylation rates of mitochondria prepared from cauliflower. Inhibition occurred with succinate, malate, citrate, isocitrate and NADH as substrates. 2. Indophenol-reductase systems with malate, succinate, isocitrate and NADH as substrates were inhibited by 5% and 15% carbon dioxide. Cytochrome c oxidase was not inhibite...