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Preparation of chromatin containing ribosomal deoxyribonucleic acid from the macronucleus of Tetrahymena pyriformis.

ABSTRACT: A method is described that enables a chromatin fraction containing ribosomal DNA (DNA containing sequences coding for rRNA) to be prepared from the macronuclei of growing or stationary cultures of Tetrahymena pyriformis. This material is obtained in yields of between 25 and 75% of the theoretical maximum. The DNA in this fraction was identified as ribosomal DNA on the basis of its density and molecular weight, and it appears not to be appreciably contaminated by other DNA. The method relies on the approximate assumption that ribosomal DNA is the smallest species of DNA in chromatin in the nucleus, and avoids the use of mechanical force, or enzyme action, to fractionate chromatin.

SUBMITTER: Jones RW

PROVIDER: S-EPMC1185757 | biostudies-other | 1978 Jul

REPOSITORIES: biostudies-other

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Histone composition of a chromatin fraction containing ribosomal deoxyribonucleic acid isolated from the macronucleus of Tetrahymena pyriformis.

Project description:The histone compositions of a chromatin fraction containing ribosomal DNA and of the remaining macronuclear chromatin of Tetrahymena pyriformis was analysed by gel electrophoresis. These chromatin fractions were used as models for transcriptionally active and inactive chromatin respectively. The extent of histone modification, as indicated by the distribution of histone between differently charged subspecies in acid-urea gels, is not grossly different in the two chromatin fractions. However, histone H1 is present, but may be differently modified in the two chromatin fractions. The histone/DNA ratio in ribosomal chromatin, measured after sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of samples of chromatin, was found to be the same whether chromatin was extracted from growing or stationary organisms, and to be approx. 40% of this ratio in the remaining macronuclear chromatin. The implications of these results for the possible structure of transcriptionally active chromatin are discussed.

| S-EPMC1185758 | biostudies-other

Mitochondrial deoxyribonucleic acid from Tetrahymena pyriformis and its kinetic complexity.

Project description:1. Mitochondrial DNA from Tetrahymena pyriformis strain T has a buoyant density (rho) of 1.685 compared with rho1.688 for whole cell DNA. Mitochondrial preparations from T. pyriformis strain W show an enrichment of a light satellite (rho1.686), although this is not obtained free from nuclear DNA (rho1.692). 2. T. pyriformis mitochondrial DNA renatures rapidly and the kinetics of this process indicate a complexity of approx. 3x10(7) daltons. 3. The base-pairing in the renaturation product is of a precise nature, since the ;melting' temperature (80.5 degrees C) is indistinguishable from that of the native DNA (80.5 degrees C). 4. Centrifugation of mitochondrial DNA in an alkaline caesium chloride density gradient gives two bands, implying the separation of the complementary strands.

| S-EPMC1185503 | biostudies-other

Accumulation of Tetrahymena pyriformis on Interfaces.

Project description:The behavior of ciliates has been studied for many years through environmental biology and the ethology of microorganisms, and recent hydrodynamic studies of microswimmers have greatly advanced our understanding of the behavioral dynamics at the single-cell level. However, the association between single-cell dynamics captured by microscopic observation and pattern dynamics obtained by macroscopic observation is not always obvious. Hence, to bridge the gap between the two, there is a need for experimental results on swarming dynamics at the mesoscopic scale. In this study, we investigated the spatial population dynamics of the ciliate, Tetrahymena pyriformis, based on quantitative data analysis. We combined the image processing of 3D micrographs and machine learning to obtain the positional data of individual cells of T. pyriformis and examined their statistical properties based on spatio-temporal data. According to the 3D spatial distribution of cells and their temporal evolution, cells accumulated both on the solid wall at the bottom surface and underneath the air-liquid interface at the top. Furthermore, we quantitatively clarified the difference in accumulation levels between the bulk and the interface by creating a simple behavioral model that incorporated quantitative accumulation coefficients in its solution. The accumulation coefficients can be compared under different conditions and between different species.

| S-EPMC8622496 | biostudies-literature

Preparation and partial characterization of cell-free protein-synthesizing extracts from Tetrahymena pyriformis.

Project description:1. We have examined methods necessary for preparing post-mitochondrial supernatants from Tetrahymena pyriformis strain HSM that are capable of efficient cell-free protein synthesis. 2. The requirements for optimum synthesis in these extracts are described. 3. Data relating to the kinetics of protein synthesis and the initiation capacity of these supernatants are presented.

| S-EPMC1162811 | biostudies-other

Amino acid sequence of cytochrome c from Tetrahymena pyriformis Phenoset A.

Project description:The cytochrome c of Tetrahymena pyriformis GL (Phenoset A) had an isoelectric point of 6.5 and by sequence the following composition: Asp(7) Asn(2) Thr(4) Ser(8) Glu(6) Gln(2) Pro(7) Gly(13) Ala(13) Val(7) Met(2) Ile(5) Leu(6) Tyr(2) Phe(5) Lys(11) His(3) Trp(1) Arg(3) Cys(2) (total 109 residues). The peptides derived from the protein afforded complete overlap, so a complete sequence could be determined without reference of homologous proteins. Alignment with other mitochondrial cytochromes c required two internal deletions totalling three residues and an N-terminal region two residues longer than, and a C-terminal region one residue shorter than, the previously known limits. The sequence was the most divergent of the known mitochondrial cytochromes c, suggesting a distant relationship of ciliates to other eukaryotes. Details of the sequence data have been deposited as Supplementary Publication no. SUP 50068 (37 pages) at The British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7 BQ, U.K., from whom copies can be obtained on the terms given in Biochem. J. (1976) 153,5.

| S-EPMC1164106 | biostudies-other

Dolichyl phosphate phosphatase from Tetrahymena pyriformis.

Project description:A soluble dolichyl phosphate phosphatase from Tetrahymena pyriformis was purified about 68-fold. The enzyme appeared to be specific for dolichyl phosphate and existed in two interrelated forms, one of mol.wt. about 500000 and the other of mol.wt. about 63000. The enzyme was strongly inhibited by 5 mM-Mn2+ and was strongly stimulated by Mg2+. Tetrahymena in the exponential growth phase contained more of this enzymic activity than cells in stationary or lag phase. The dolichyl phosphate phosphatase may be loosely bound to mitochondrial membranes. Two roles proposed for this enzyme are (1) that of releasing dolichol from its phosphorylated biosynthetic form for its use in the cell as unesterified dolichol or dolichyl ester and/or (2) that of regulation of synthesis of glycoproteins or some other glycosylated compound.

| S-EPMC1163075 | biostudies-other

Screening Snake Venoms for Toxicity to Tetrahymena Pyriformis Revealed Anti-Protozoan Activity of Cobra Cytotoxins.

Project description:Snake venoms possess lethal activities against different organisms, ranging from bacteria to higher vertebrates. Several venoms were shown to be active against protozoa, however, data about the anti-protozoan activity of cobra and viper venoms are very scarce. We tested the effects of venoms from several snake species on the ciliate Tetrahymena pyriformis. The venoms tested induced T. pyriformis immobilization, followed by death, the most pronounced effect being observed for cobra Naja sumatrana venom. The active polypeptides were isolated from this venom by a combination of gel-filtration, ion exchange and reversed-phase HPLC and analyzed by mass spectrometry. It was found that these were cytotoxins of the three-finger toxin family. The cytotoxins from several cobra species were tested and manifested toxicity for infusorians. Light microscopy revealed that, because of the cytotoxin action, the infusorians' morphology was changed greatly, from teardrop-like to an almost spherical shape, this alteration being accompanied by a leakage of cell contents. Fluorescence microscopy showed that the fluorescently labelled cytotoxin 2 from cobra N. oxiana was localized mainly at the membrane of killed infusorians, indicating that cytotoxins may kill T. pyriformis by causing membrane rupture. This work is the first evidence of the antiprotozoal activity of cobra venom cytotoxins, as demonstrated by the example of the ciliate T. pyriformis.

| S-EPMC7290292 | biostudies-literature

Prediction of the aquatic toxicity of aromatic compounds to tetrahymena pyriformis through support vector regression.

Project description:Toxicity evaluation is an extremely important process during drug development. It is usually initiated by experiments on animals, which is time-consuming and costly. To speed up such a process, a quantitative structure-activity relationship (QSAR) study was performed to develop a computational model for correlating the structures of 581 aromatic compounds with their aquatic toxicity to tetrahymena pyriformis. A set of 68 molecular descriptors derived solely from the structures of the aromatic compounds were calculated based on Gaussian 03, HyperChem 7.5, and TSAR V3.3. A comprehensive feature selection method, minimum Redundancy Maximum Relevance (mRMR)-genetic algorithm (GA)-support vector regression (SVR) method, was applied to select the best descriptor subset in QSAR analysis. The SVR method was employed to model the toxicity potency from a training set of 500 compounds. Five-fold cross-validation method was used to optimize the parameters of SVR model. The new SVR model was tested on an independent dataset of 81 compounds. Both high internal consistent and external predictive rates were obtained, indicating the SVR model is very promising to become an effective tool for fast detecting the toxicity.

| S-EPMC5564774 | biostudies-literature

The effect of excess mevalonic acid on ubiquinone and tetrahymanol biosynthesis in Tetrahymena pyriformis.

Project description:When T. pyriformis is grown in the presence of 10(-2)M-mevalonic acid, the uptake exceeds the cell's requirement for this biosynthetic intermediate. The majority of the excess mevalonic acid is diverted into ubiquinone-8 biosynthesis whereas the biosynthesis of tetrahymanol, the major product of the mevalonic acid pathway, is unchanged. In the presence of excess external mevalonic acid, the biosynthesis of mevalonic acid by the cell is inhibited. It is proposed that ubiquinone biosynthesis is normally regulated by mevalonic acid availability, whereas tetrahymanol biosynthesis is regulated primarily at a later point in the pathway.

| S-EPMC1145090 | biostudies-other

Isolation of deoxyribonucleic acid and ribosomal ribonucleic acid from bacteria.

Project description:1. Nucleic acids were released from Escherichia coli by lysing with tri-iso-propylnaphthalene sulphonate and 4-aminosalicylate and then extracting with a phenol-cresol mixture. 2. Nucleic acids were similarly released from Bacillus subtilis after initial treatment with lysozyme. 3. DNA was sedimented after careful precipitation with m-cresol or 2-butoxyethanol (0.1-0.12vol.) in the presence of 20% sodium benzoate. 4. Contaminating ribosomal RNA was removed by precipitation in the presence of 4m-sodium chloride or by extracting DNA with an acetate-butyrate mixture, in which RNA is insoluble. 5. The DNA from B. subtilis has a transforming ability of 0.3-0.6% for the tryptophan marker. 6. Ribosomal RNA was then precipitated with rapidly labelled RNA by the addition of an equal volume of 2-butoxyethanol. 7. There was good separation of the nucleic acids from protein and polysaccharides.

| S-EPMC1270570 | biostudies-other

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