0000000000371422
AUTHOR
Atsuko Totsuka
Methode zur Bestimmung der Bleomycin-inaktivierenden Enzymaktivit�t in Geweben
Gewebe enthalten ein Enzym, das Bleomycin (BLM) inaktiviert. Die Enzymaktivitat ist in Extrakten aus verschiedenen Geweben unterschiedlich hoch. In der vorliegenden Arbeit wird eine Methode zur Bestimmung der BLM-inaktivierenden Enzymaktivitat aus Organen und Geweben von Mausen beschrieben. Diese BLM-inaktivierende Enzymaktivitat ist in Extrakten aus Leber am hochsten, Hoden, Milz, Lunge und Gehirn weisen geringere Aktivitaten auf; in Hautgewebe fehlt dieses Enzym fast vollig.
Bleomycin: Action on growth of oncogenic RNA viruses and on cell transformation
Bleomycin (BLM) inhibits cell proliferation of noninfected chick embryo fibroblasts by blocking their DNA synthesis selectively. Chick embryo fibroblasts have beentransformed by Schmidt-Ruppin D strain of Rous Sarcoma Virus. Transformation has been determined by a focus assay. Foci formation is strongly reduced by BLM. Virus replication is inhibited by BLM in growing and confluent monolayer cells. This result might be explained by the observation that this drug reduces proliferation of growing and of confluent monolayer cells very sensitively. During the first 24 hours after infection the BLM inhibitory effect is more pronounced than in the case of BLM-application during the period 24--48 h…
Poly(adenosine diphosphate-ribose) polymerase in quail oviduct. Changes during estrogen and progesterone induction
Abstract The activities of the following enzymes have been determined in nuclei of quail oviducts in response to exogenous stimulation of the birds with diethylstilbestrol, used as an estrogen analogue and progesterone: DNA dependent DNA polymerase, DNA dependent RNA polymerase I and II and poly(adenosine diphosphate-ribose) [=poly(ADP-Rib)] polymerase. During primary stimulation with the estrogen analogue the activities of the four DNA dependent polymerases increase to about the same degree. Upon withdrawal of the hormones the levels of the enzymes drop to values known from nuclei from unstimulated quail oviducts. The secondary stimulation with the estrogen analogue causes a significant in…
Influence of template inactivators on the binding of DNA polymerase to DNA.
The agents daunomycin, ethidium bromide, distamycin A and cytochrome c inhibit DNA dependent DNA polymerase I (E. coli) reaction competitively to DNA. The influence of these template inactivators on the binding of DNA polymerase to native as well as denatured DNA has been determined by affinity chromatography. Cytochrome c blocks the binding of the enzyme to double-stranded and to single-stranded DNA Sepharose. In contrast to these results daunomycin, ethidium bromide or distamycin A reduce the binding affinity only with denatured DNA Sepharose as matrix. These data are discussed with respect to the modification by template inactivators of the affinity of DNA to the different binding sites …
Bleomycin inhibition of DNA synthesis in isolated enzyme systems and in intact cell systems.
Abstract Blcomycin (BLM) inhibits DNA and RNA synthesis in different isolated enzyme systems. The inhibition effect can be reduced by adcling RNA to the reaction mixture. The activity of the RNA dependent DNA polymerase and of a cell-free protein synthesizing system is not affected by BLM. The antibiotic reduces cell proliferation (L5178y mouse lymphoma cells) in vitro at low concentrations by cytostatis and at higher concentrations by cytotoxicity. In BLM-treated L5178y cells DNA synthesis is strongly reduced, while RNA and protein synthesis are not affected. In vivo , using growing quail oviducts, cell proliferation and cytodifferentiation are markedly inhibited after BLM treatment. This …