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The localization of cytoplasmic free calcium and a dihydropyridine (DHP) receptor, a putative calcium channel, was recorded during the opposite graviresponses of tip-growing Chara rhizoids and Chara protonemata by using the calcium indicator Calcium Crimson and a fluorescently labeled dihydropyridine (FL-DHP). In upward (negatively gravitropically) growing(More)
The fact that every antibody also has antigenic properties leads to the existence of a functional network of interacting antibodies and lymphocytes in the immune system. With a minimum set of assumptions about the nature of these interactions some of the principal features of the immune response such as normal primary and secondary response, low and high(More)
We suggest that temporal oscillations of concentrations of intermediates in biochemical reaction systems may enhance the efficiency of free energy conversion (reduce dissipation) in those reactions. Experiments on glycolysis are used to estimate the Gibbs free energy changes along the glycolysis mechanism, and to postulate a construct for the glycolysis(More)
Molecular probes are widely used tools in chemical biology that allow tracing of bioactive metabolites and selective labeling of proteins and other biomacromolecules. A common structural motif for such probes consists of a reporter that can be attached by copper(I)-catalyzed 1,2,3-triazole formation between terminal alkynes and azides to a reactive(More)
1. The first example of a P450-dependent N-hydroxylation of an aminoguanidine (amidinohydrazone) is reported for 2-amino-5-chlorobenzophenone amidinohydrazone 1 (G 256) as substrate. 2. The N-hydroxylated metabolite 2 (2-amino-5-chlorobenzophenone N-hydroxyamidinohydrazone NOH-G256) and a further metabolite of 1, the phenol 3, were identified by tlc and ms(More)
The phenomenon of the wandering point on a blank sheet of paper in serial reproductions is the starting point of an investigation of the perceptual field structure of homogeneous stimulus areas; 609 stimulus points distributed regularly in 21 rows and 29 columns on a DIN A4 sheet were presented successively to 10 subjects and had to be reproduced(More)
The Escherichia coli somatic pilus, 987P, has been purified after removal by homogenization from a 987P+ enterotoxigenic E. coli. Cell-free pili were precipitated by the addition of MgCl2, collected, and dissolved in MgCl2-free buffer. Five cycles of precipitation and dissolving resulted in a preparation of 987P that was judged to be homogeneous based on(More)
DNA repair-deficient (xeroderma pigmentosum group A (XPA)) and DNA repair-proficient (normal) human skin fibroblasts were genetically engineered by transformation with a controllable human cytochrome P450 (CYP)1A1 expression vector. Induction of CYP1A1 enabled these cells to metabolize (+/-)-benzo[a]pyrene-trans-7,8-dihydrodiol (BPD) into a potent(More)