The absorption characteristics of Cd(2+) by 10- to 12-day-old soybean plants (Glycine max cv Williams) were investigated with respect to influence of Cd concentration on adsorption to root surfaces, root absorption, transport kinetics and interaction with the nutrient cations Cu(2+), Fe(2+), Mn(2+), and Zn(2+). The fraction of nonexchangeable Cd bound to roots remained relatively constant at 20...

Bernhard Huchzermeyer Botanisches Institut, Tierärztliche Hochschule, Bünteweg 17d, D-3000 Hannover 71, Bundesrepublik Deutschland Z. Naturforsch. 43c, 133-139 (1988); received June 19, 1987 Chloroplasts, CF0CF,, Light Triggered ATPase Activity, Regulation. Mechanism of Inactivation It has been found that the decay of light triggered ATPase activity is paralleled by nonexchangeable type of bind...

Proton NMR experiments on an intact plasmid supercoiled DNA molecule are reported. Spectra of the hydrogen-bonded exchangeable imino protons and nonexchangeable aromatic protons of pIns36 (7,200 base pairs; Mr 5 x 10(6)) were examined at 240 and 360 MHz. In contrast to linear DNA of comparable size in which the signals from these protons are broadened almost beyond detection, the supercoiled DN...

To discover semantically coherent topics from topic models, knowledge-based topic models have been proposed to incorporate prior knowledge into topic models. Moreover, some researchers propose lifelong topic models (LTM) to mine prior knowledge from topics generated from multi-domain corpus without human intervene. LTM incorporates the learned knowledge from multi-domain corpus into topic model...

Myoglobin and lysozyme picosecond internal dynamics in solution is compared to that in hydrated powders by quasielastic incoherent neutron scattering. This technique is sensitive to the motions of the nonexchangeable hydrogen atoms in a sample. Because these are homogeneously distributed throughout the protein structure, the average dynamics of the protein is described. We first propose an orig...

The turnover of the four major erythrocyte phospholipids has been studied with (32)P, both in vivo and in vitro, in man and the dog. Phosphatidyl serine and phosphatidyl ethanolamine appeared to be stable erythrocyte lipids in both species. Turnover of the phosphate moiety of lecithin and sphingomyelin in the circulating erythrocytes of these two species seems entirely due to an exchange of the...

The removal of noncoding sequences (introns) from eukaryotic precursor mRNA is catalyzed by the spliceosome, a dynamic assembly involving specific and sequential RNA-RNA and RNA-protein interactions. An essential RNA-RNA pairing between the U2 small nuclear (sn)RNA and a complementary consensus sequence of the intron, called the branch site, results in positioning of the 2'OH of an unpaired int...

The polyamines putrescine, spermidine, and spermine are multivalent cations that bind to anionic cell constituents such as nucleic acids. Their distribution between free and bound states within the cell is not known. Such knowledge would be important in relation to the negative control of polyamine synthesis. We report a tracer experiment in which [14C]ornithine was added to logarithmically gro...

Probenecid has been shown to delay the plasma clearance of methotrexate in the rat and to reduce both hepatic and renal excretion of methotrexate in this animal model. In order to probe the mechanism by which probenecid alters hepatic excretion of the antifolate, studies assessed the effects of probenecid on transport, accumulation, distribution, and release of methotrex ate in the rat hepatocy...