Cees van Dijk

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Stereoselective hydrolysis at pH 7.5 and 37 degrees of C(+/-)P(+/-)-soman by liver homogenate and plasma from rat, guinea pig and marmoset, and by human plasma is studied by using the four single stereoisomers. The fast hydrolysis of the C(+/-)P(+)-isomers is monitored titrimetrically, whereas the decay of the much slower reacting C(+/-)P(-)-isomers is(More)
The fallen concentration of one of the two isomers of soman (1,2,2-trimethylpropyl methylphosphonofluoridate), i.e., C(+)P(-)-soman, was investigated in plasma and in homogenates of brain, lung, liver, kidney, diaphragm, skeletal muscle and mucosa of small intestines from rat, guinea pig and marmoset, and in human plasma (pH 7.5, 37 degrees). The decrease(More)
The relative hydrophobicity and interaction of flavonoids with artificial membranes using vesicles was studied. At the same degree of hydroxylation, flavones were slightly more hydrophobic than flavanones. Flavonoids possess a hydrophobic character and are weak acids. For this reason, their uncoupling efficiency of the membrane potential was studied using(More)
During the storage season changes in the chemical composition of the pectin moiety of the cell walls of raw potatoes were studied. This compositional analysis was performed for the cultivars Nicola and Irene, which represent two extremes with regard to sensory-perceived texture. Both cultivars were divided into three size categories. From each size category(More)
A c-type hexaheme nitrite reductase (NiR) isolated from nitrate-grown cells of Desulfovibrio desulfuricans (Dd) ATCC 27774 catalyses the six-electron reduction of nitrite to ammonia. Previous electrochemical studies demonstrated that a simple electrocatalytic mechanism can be applied to this system (Moreno, C., Costa, C., Moura, I., LeGall, J., Liu, M. Y.,(More)
The production of antibodies against the organophosphorus hapten soman has been undertaken in vivo in rabbits and in vitro by employing monoclonal techniques. The polyclonal rabbit antibodies did not cross-react with soman but were inhibited by soman analogs in a competitive inhibition enzyme immunoassay ( CIEIA ). In contrast the monoclonal antisoman(More)
The continuum and single jump treatments of ion transport through black lipid membranes predict experimentally distinguishable results, even when the same mechanistic assumptions are made and the same potential-distance profile is used. On the basis of steady-state current-voltage curves for nonactin-mediated transport of potassium ions, we find that the(More)
After incubation (37 degrees) of rat blood or plasma with the nerve agent soman, (CH3)3C(CH3)C(H)O(CH3)P(O)F (7.7 microM), for 10 min, only a small amount of this organophosphate (7 or 1%, respectively) is left, as determined enzymatically (acetylcholinesterase) and gas chromatographically. Comparison of the results obtained with both analyses shows that(More)
The relationships between the redox potential of the brine, during fermentation of white cabbage into sauerkraut of two early and two late fermentation processes, and the changes in the amount of sugars, organic acids, the redox potential of the brine and of the ascorbic acid redox couple, and pH are described. The trend in the change of the redox potential(More)
Variable preheating conditions allowed the modification of the firmness of two green bean cultivars after processing. The aim of this study was to elucidate the biochemical basis of this phenomenon and to relate pectin differences to different inherent firmness of two cultivars. The preheating temperature, which resulted in the highest retention of firmness(More)