We have recently developed a method for the analysis of toxins in single specimens of the mush­ room Amanita phalloides (Fr.) Seer.1. Separation of the different toxins was achieved by column chro­ matography, on Sephadex LH20 in water, of a methanolic extract of fresh or dried mushrooms, followed by further purification on thinlayers of silica gel, spectrophotometric evaluation, and, final­ ly...

Exposure of cultured human hepatoma cells (Hep G2) to medium containing 2% (v/v) dimethyl sulphoxide resulted in an approximate doubling in the activity of 6-aminolaevulinate dehydratase, an increase in the haem content and a decreased growth rate; induced enzyme activity was decrease by 50% after treatment with a-amanitin. The findings are strikingly similar to those seen in murine Friend-viru...

An enzymatic activity in crude extracts of macronuclei from the hypotrichous ciliate Oxytricha nova catalyzes the synthesis of RNA consisting of (C4A4)n using an oligodeoxynucleotide template of the telomeric sequence (dG4T4)n. Single-stranded (dG4T4)n is an effective template if it has a random sequence at its 5' end. The enzyme will not use a (dG4T4)n template of any length (up to 64 bases) i...

As part of our systematic study of Korean toxic mushrooms, we have investigated the constituents of Amanita subjunquillea. The column chromatographic separation of the MeOH extract of A. subjunquillea led to the isolation of four ergosterols, two cerebrosides and four cyclopeptides. Their structures were determined by spectroscopic methods to be (22E,24R)-5alpha,8alpha-epidioxyergosta-6,9,22-tr...

In an effort to develop mild conditions for the isolation of DNA-dependent RNA polymerase II, we have used DNase I covalently coupled to Sepharose 4B to digest chromatin from hypotonically lysed nuclei from rooster liver. The RNA polymerase II released was at least 2 times more active in in vitro transcription than was RNA polymerase II prepared by the conventional method of sonication of chrom...

This paper presents evidence that maternal mRNA is responsible for the early increase in HPRT activity in preimplantation mouse embryos. Increase of HPRT activity is demonstrable from as early as 6 h postfertilization when there is barely detectable synthesis of embryonic RNA. The increase is sensitive to cycloheximide and thus requires protein synthesis, whereas it is insensitive to alpha-aman...

RNA synthesis in 2-32 cell embryos, as assessed by alpha-amanitin-sensitive 3H-uridine incorporation, was first detectable in 4-cell stage rabbit and 8-cell stage sheep embryos. In the rabbit, uridine incorporation was detectable at the 2-cell stage but was unaltered by alpha-amanitin, indicating synthesis of non-polymerase II-dependent RNA species. Initiation of mRNA synthesis as determined by...

Endogenous RNA polymerase activity of isolated nuclei from Physarum polycephalum was determined at high (400 mM KCl) and low (5--100 mM KCl) ionic strength. The activity of RNA polymerase B (alpha-amanitin-sensitive UMP incorporation) and of RNA polymerase A (plus C) (alpha-amanitin-resistant UMP incorporation) was compared in accurately sized nuclear samples derived from macroplasmodia at dist...