We report the complete nucleotide sequence of the Tetrahymena pyriformis mitochondrial genome and a comparison of its gene content and organization with that of Paramecium aurelia mtDNA. T. pyriformis mtDNA is a linear molecule of 47,172 bp (78.7 % A+T) excluding telomeric sequences (identical tandem repeats of 31 bp at each end of the genome). In addition to genes encoding the previously descr...

An iron-containing superoxide dismutase has been purified from the protozoan Tetrahymena pyriformis. It has a molecular weight of 85,000 and is composed of four subunits of equal size. The tetramer contains 2.5 g atoms of ferric iron. Visible absorption and electron spin resonance spectra closely resemble those of other iron-containing superoxide dismutases. The amino acid sequence of the iron ...

The histone composition of the ribosomal gene containing chromatin (rChromatin) of the ciliated protozoan Tetrahymena pyriformis has been investigated using purified nucleolar fractions in which ribosomal DNA constitutes 65-82% of the total DNA. In isolated nucleoli, rChromatin largely retains the periodic activated structure characteristic of rChromatin in the nucleus. For all five major histo...

We have found that binding of poly(U,G) to single-stranded DNA decreases its mobility in 0.3% agarose gels. Differential binding to the complementary strands of denatured duplex DNA provides a simple method for strand separation. The method is shown to work with bacteriophage lambda DNA, adenovirus DNA and mtDNA for Tetrahymena pyriformis. In all cases the strand that binds more poly(U,G) in Cs...

VAN DER ZANT, W. C. AND NELSON, F. E. 1953 Proteolysis by Streptococcus lactis grown in milk with and without controlled pH. J. DairySci., 36, 1104-1111. VAN DER ZANT, W. C. 1957 Proteolytic enzymes from Pseudomonas putrifaciens. I. Characteristics of an extracellular proteolytic enzyme system. Food Research, 22, 151-163. VAN HEYNINGEN, W. E. 1940 The proteinases of Clostridium histolyticurnm. ...

Tetrahymena pyriformis was grown on chemically defined medium in the presence of 5-bromodeoxyuridine (BUdR). Under these growth conditions more than 60% of the thymidine sites in DNA were substituted with BUdR. It was found that RNA synthesis was strongly inhibited by the presence of BUdR in DNA. To assure that incorporation of BUdR into DNA was a prerequisite of the effect observed, BUdR was a...

An apparatus and a method for rapidly determining chemical toxicity have been evaluated as an alternative to the rabbit eye initancy test (Draize). The toxicity monitor includes an automated scoring of how motile biological cells (Tetrahymena pyriformis) slow down or otherwise change their swimming patterns in a hostile chemical environment. The method, called the Motility Assay (MA), is tested...

WO major kinds of mechanisms controlling the expression of hereditary Tmating type specificities have been described among the ciliates. In Euplotes patella (KIMBALL 1942; POWERS 1943; SONNEBORN 1947), Euplotes uannus ( HECKMANN 1961 j and Paramecium bursaria ( JENNINGS 1942; SIEGEL and LARISON 1960; SIEGEL 1963) , mating types are inherited as if uniquely controlled by simple Mendelian differe...