The effect of growth of Tetrahymena pyriformis in ethidium bromide (EthBr) on the structure and synthesis of mitochondrial DNA (mtDNA) has been investigated. During the first 5 h of growth in EthBr, mtDNA synthesis is inhibited 95% or more. After 10-15 h, this block is partially released and large numbers of replicating molecules accumulate, indicating that inhibition by EthBr primarily affects...

Actin from Tetrahymena pyriformis has been purified by monitoring the presence of the actin gene product with an antiserum against a synthetic N-terminal peptide deduced from the nucleotide sequence of the Tetrahymena actin gene that we cloned previously. This highly purified Tetrahymena actin shares many essential properties with ubiquitous actin, including ion-dependent polymerization to micr...

an alternative in vitro approach to drug screening has been the use of human cell cultures for antiviral agents and microbial cell cultures for the assessment of the carcinogenic potential of selected compounds. a number of protozoan species have been also used as drug screens for anti-protozoal agents. the ciliated protozoan tetrahymena pyriformis species has been widely utilised as a drug scr...

Cultures of Tetrahymena pyriformis, T. hegewishi and T. malaccensis have been studied with regard to control of cell volume and cellular dry weight. Cell volume was measured on cells suspended in 0.9% sodium chloride + 0.1% sodium azide using a Multisizer cell counter (Coulter). Tetrahymena were grown at different temperatures and under various up- or downshift conditions. In all cases the chan...

The chemotactic properties of tuftsin (H-TKPR-OH), tuftsin derivatives (H-KPR-OH, H-TKPKG-NH(2), Ac-TKPKG-NH(2)) and TKPKG-based oligotuftsins (T20, T30, T40) were investigated in Tetrahymena pyriformis GL. In contrast to its effects on Mammalia, tuftsin elicited chemorepellent or neutral responses; truncation of the N-terminal part (KPR) led to similar results, though with more neutral effects...