Some Biological Characteristics of Tetrahymena corlissi Isolated from Guppy in Thailand.

Transcriptional properties of nucleoli isolated from Tetrahymena.

Nucleoli can be isolated from Tetrahymena in a yield of 30-60%. The isolated nucleoli contain rDNA (at least 90% pure) and have a protein to DNA ratio of 30:1. The endogenous RNA-polymerase activity of the r-chromatin has the following properties: (i) The in vitro transcript has a maximal size identical to the in vivo 35S rRNA precursor, demonstrating correct termination on the gene, (ii) 79% o...

DNA from isolated pellicles of Tetrahymena.

Large pellicle fragments were isolated from Tetrahymena pyriformis, strain T, by 2 procedures : homogenization after treatment with 40 % ethanol at — 20 °C, or direct homogenization in a sucrose-EDTA buffer. All preparations contained entrapped mitochondria. DNA prepared from these pellicles was analysed on a CsCl gradient, and contained 3 components of buoyant densities 1-685, 1-688, and 1698 ...

Laboratory characteristics of poxviruses isolated from captive elephants in Germany

Termination of transcription in nucleoli isolated from Tetrahymena.

Correct termination of transcription of the rRNA gene in nucleoli isolated from Tetrahymena is dependent on a protein factor with a molecular weight between 50,000 and 100,000. At low ionic strength the endogenous RNA polymerase synthesizes a transcript identical in size to the precursor rRNA extracted from cells. In the presence of ammonium sulfate, however, the RNA polymerase reads through th...

Some chemical and biological characteristics of showdomycin.

The chemical properties of showdomycin, a maleimide type antibiotic, were very similar to, but its biological properties rather different from, those of N-ethylmaleimide. Another maleimide derivative, citraconimide, showed very low reactivity both in chemical and biological reactions compared with the above two compounds. The results of quantitative analyses of cellular sulfhydryl content of Es...