BACKGROUND & AIMS Treatment with tumor necrosis factor (TNF) induces murine hepatocyte apoptosis in vitro and in vivo when sensitizing concentrations of toxins are present. The aim of this study was to investigate whether endogenously formed TNF contributes to liver failure caused by hepatotoxins. METHODS The extent of liver damage, induced by alpha-amanitin or actinomycin D (ActD), was exami...

Recently, it has been demonstrated that nitrogen mustard-induced N-alkylpurines are excised rapidly from actively transcribing genes, while they persist longer in noncoding regions and in the genome overall. It was suggested that transcriptional activity is implicated as a regulatory element in the efficient removal of lesions. By treating cells or not with the transcription inhibitor alpha-ama...

A systematic approach to the in vitro measurement of HNA-dependent RNA polymerase activities in nuclei from immature rat uterus has been undertaken in order to evaluate the early effects of estradiol. The experimental conditions include excess of nucleoside .i’-triphosphate and short time assays (6 min) at low temperature (25”) in order to obtain the maximal velocity of the reaction and to mini...

The genetic basis of variation in resistance to natural toxins is of interest for both ecological and evolutionary genetics. The wide variety of larval resources used by Drosophila, both within and between species, makes flies an excellent system for studying causes and consequences of selection resulting from exposure to natural toxins associated with different resources. In this study we carr...

Zygotic transcription was analyzed in embryos of the glossiphoniid leech Helobdella triserialis by autoradiographic detection of tritiated uridine incorporated in the presence or absence of low concentrations of alpha-amanitin. RNA synthesis was first detected after the second cleavage and alpha-amanitin-sensitive RNA synthesis was first detected during the divisions yielding the embryonic stem...

Mouse myeloma cells have previously been shown (L. B. Schwartz, V. E. F. Sklar, J. A. Jaehning, R. Weinmann & R. G. Roeder, submitted for publication) to contain two chromatographically distinct forms of RNA polymerase III (designated III(A) and III(B)). The enzymes are unaffected by low alpha-amanitin concentrations which completely inhibit RNA polymerase II, but they exhibit characteristic in...

DNA-dependent RNA polymerases I, II, and III were isolated and partially purified from KB (human) cells 18 hr after infection with adenovirus 2. As reported previously for the enzymes from other animal cells, RNA polymerase II was completely sensitive to low concentrations of alpha-amanitin (50% inhibition at 0.02 mug/ml), RNA polymerase III was completely sensitive to high concentrations of al...

A systematic approach to the in vitro measurement of HNA-dependent RNA polymerase activities in nuclei from immature rat uterus has been undertaken in order to evaluate the early effects of estradiol. The experimental conditions include excess of nucleoside .i’-triphosphate and short time assays (6 min) at low temperature (25”) in order to obtain the maximal velocity of the reaction and to mini...

Toxins could be effective anticancer drugs, if their selective delivery into cancer cells could be achieved. We have shown that the energy of membrane-associated folding of water-soluble membrane peptides of the pHLIP (pH low insertion peptide) family could be used to move cell-impermeable cargo across the lipid bilayer into the cytoplasm of cancer cells. Here we present the results of a study ...

DNA-dependent RNA polymerases of immature and castrated rat uteri were studied after estradiol administration. The enzymes were solubilized from either whole uterus homogenate or nuclei and their activities were measured on an exogenous DNA template. oc-Amanitin was used to distinguish Lu-amanitin-resistant from cu-amanitin-senitive forms of the enzyme. The number of oc-amanitin-sensitive RNA p...