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Biomedical subjects

R Lindigkeit

Publications and source records attributed to R Lindigkeit.

At least 37 records · Page 2Linked to original sources
PubMed1977

An improved method for the preparation of the DNA-dependent RNA polymerase B from calf thymus.

A simplified method is described for the large-scale preparation of a highly purified DNA-dependent RNA polymerase B from calf thymus. The method includes homogenization and lysis of the tissue, chromatography on DEAE-cellulose, phosphocellulose, hydroxylapatite-Sephadex G-10 and, once again, phosphocellulose. The procedure avoids the preparation of nuclei, the use of sonication, ammonium sulphate precipitations and dialysis steps and needs no ultracentrifugation.

Animals↗
PubMed1975

A computer simulation model for analysis of conformation of nuclear chromatin and of the transcription process.

Based on experimental data (see Lindigkeit et al., 1974) an algorithmic computer model was devised with the following parameters: (a) nbr. and position of hypothetic blocker sites at the DNA which inhibit transcription in such a manner that distinct RNA chain lengths arise; (2) time depending probability functions that a polymerase molecule (p.m.) is able to pass a blocker site; (3) time depending rate of viability of synthetizing p.m. and (4) distribution of the p.m. on the template at the time t0. For comparison between observed and computed results 3 parameters are used: (1) distribution of chain lengths of RNA molecules in vitro synthetized; (2) their total amount and (3) the number of active p.m. By means of comparisons between computed and experimental results it is possible to test hypotheses about internal structural and functional parameters of the system under investigation, e.g. estimation of the rel. influence of template vs. p.m. characters in the transcription process, hypotheses about the type of distribution of p.m. at time t0, their initiation and salt depending removal probability of the blocker structures.

Cell Nucleus↗
PubMed1975

Evidence of altered histone interactions, as investigated by removal of histones, in chromatin isolated from rat liver nuclei by a conventional method.

It is shown that the release of the slightly lysine-rich histones f2a2 and f2b by 0.4 M ammonium sulfate from conventionally isolated chromatin is diminished in comparison to the lysed nuclei. The change in extractability is further demonstrated by the application of ethidium bromide. At a molar input ratio of 0.09 (moles ethidium bromide/moles nucleotide) and 0.4 M ammonium sulfate the slightly lysine-rich histones are released from the chromatin to 70 - 80% if the lysed nuclei are used. At 0.1 M ammonium sulfate ethidium bromide effected also a release of 50 % of histone f1. Comparable effects could not be observed with chromatin prepared in a conventional way but instead a tendency towards loss of histone f3 in the presence of ethidium bromide was observed.

Ammonium Sulfate↗
PubMed1975

Effect of RNA synthesis on the binding of 3H-cortisol to nuclear ribonucleoprotein particles from rat liver carrying DNA-like RNA in vivo.

3H-cortisol was found to associate with rat liver nuclear 30S ribonucleoprotein particles carrying D-RNA in vivo. No interaction was detectable when RNA synthesis was inhibited by alpha-amanitine. The association appears to be specifically for RNP carrying RNA synthesized after the administration of cortisol to adrenalectomized rats. The DNA/protein/RNA ratio of rat liver nuclei was not effected by alpha-amanitine under our conditions. However, the drug caused a 5-10 fold decrease in nuclear uptake of cortisol. The results are discussed in relation to a supposed transfer of cortisol-receptor complexes from the chromatin template to the nascent RNA chains.

Adrenalectomy↗