scholarly journals Evidence for a pronounced secretion of cyclic AMP by Tetrahymena.

1980 ◽  
Vol 85 (3) ◽  
pp. 910-915 ◽  
Author(s):  
S G Nandini-Kishore ◽  
G A Thompson
Keyword(s):  
Cyclic Amp ◽  
Growth Medium ◽  
Phosphate Buffer ◽  
External Medium ◽  
Active Material ◽  
Tetrahymena Pyriformis ◽  
Unicellular Eukaryote ◽  
Beef Heart ◽  
Nutrient Media ◽  
Complete Hydrolysis

The unicellular eukaryote Tetrahymena pyriformis secretes significant amounts of cyclic AMP into its external medium. Cells transferred from growth medium into any of the following three different non-nutrient media: (a) 5 mM phosphate buffer containing 47 mM NaCl and 1 mM MgSO4, (b) 10 mM Tris, or (c) 1.3 mM Tris containing 1 mM citrate and 1 mM Ca(OH)2, released to the outside almost 60--80% of the total cyclic AMP produced during 2--5 h of incubation. Tris-citrate-Ca+2 medium was chosen for further experiments because of its minimal nonspecific interference in the cyclic AMP radioimmunoassay. The identity of the secreted material recognized as cyclic AMP by radioimmunoassay was confirmed by demonstrating its almost complete hydrolysis with commerical beef heart phosphodiesterase. Furthermore, the radioimmunoassay-active material in the concentrated medium co-chromatographed on paper with [3H]cyclic AMP, as judged by assay of the eluted material. After resuspending cells in Tris-citrate-Ca2+ medium, the extracellular concentration of cyclic AMP rose steadily over a 5-h period, reaching a level equvalent to approximately 35--50 pmol cyclic AMP/10(6) cells vs. an internal cyclic AMP quantity at 5 h of 8--10 pmol/10(6) cells. After 5 h, the level of extracellular cyclic AMP reached a plateau. There was no degradation or uptake of external cyclic AMP by the cells during this period.

Preferential inhibition of rDNA transcription by 5-bromodeoxyuridine

1977 ◽  
Vol 25 (1) ◽  
pp. 95-102
Author(s):  
A.E. Lykkesfeldt ◽  
H.A. Andersen
Keyword(s):  
Growth Medium ◽  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Tetrahymena Pyriformis ◽  
Degree Of Substitution ◽  
Rdna Transcription ◽  
Total Rna

On a chemically defined growth medium the degree of substitution of thymidine with 5-bromodeoxyuridine (BUdR) in DNA of Tetrahymena pyriformis was controlled by the concentration of tetrahydrofiolic acid, BUdR and thymidine in the medium. A correlation between the degree of BUdR substitution in DNA and the reduction in rate of total RNA synthesis has been established. It was found that the reduction of total RNA synthesis results from inhibition of transcription of all RNA species which have been measured. However, independent of the degree of BUdR substitution in DNA, a preferential inhibition of the synthesis of 25s and 17s ribosomal RNA was found. It is concluded that the various genes may respond differently to BUdR substitution with respect to transcription.

scholarly journals Cyclic AMP metabolism in the cell cycle of tetrahymena pyriformis

FEBS Letters ◽  
1976 ◽  
Vol 65 (2) ◽  
pp. 152-154 ◽  
Author(s):  
J.R. Dickinson ◽  
M.G. Graves ◽  
B.E.P. Swoboda
Keyword(s):  
Cell Cycle ◽  
Cyclic Amp ◽  
Tetrahymena Pyriformis

Release of protoplasts from the galactose oxidase producing mold, Dactylium dendroides

1983 ◽  
Vol 29 (7) ◽  
pp. 763-766 ◽  
Author(s):  
Déa Amaral ◽  
Doroty Kubicki ◽  
Hector F. Terenzi
Keyword(s):  
Growth Medium ◽  
Phosphate Buffer ◽  
Normal Growth ◽  
Galactose Oxidase ◽  
Lytic Enzyme ◽  
Considerable Importance ◽  
Digestive Juice ◽  
Osmotic Stabilizer ◽  
Dactylium Dendroides

Osmotically sensitive protoplasts were released from the mycelium of Dactylium dendroides, using Megalobolinus paranaguensis digestive juice as a lytic enzyme. The conditions for obtaining stable protoplasts were determined. The maximum number of protoplasts was obtained from 15-h growing mycelium, using MgSO4 as osmotic stabilizer, in the presence of 0.015 M Sorensen phosphate buffer, pH 5.6. MgSO4 proved to be of considerable importance in the release of protoplasts in this fungus. Regeneration of the protoplasts was demonstrated in normal growth medium supplemented with 0.8 M mannitol and 2.5% agar.

A WIDE-SPECTRUM ANTIBIOTIC PRODUCED BY A SPECIES OF SORANGIUM

1966 ◽  
Vol 12 (2) ◽  
pp. 221-230 ◽  
Author(s):  
E. A. Peterson ◽  
D. C. Gillespie ◽  
F. D. Cook
Keyword(s):  
Low Temperature ◽  
Aqueous Solutions ◽  
Phosphate Buffer ◽  
Wide Spectrum ◽  
Active Material ◽  
Gram Negative Bacteria ◽  
Alkaline Ph ◽  
Gram Negative ◽  
Ether Extraction ◽  
High Degree

A soil-borne myxobacter identified as a species of Sorangium produced a potent antibiotic capable of inhibiting growth of a wide variety of microorganisms including Gram-positive and Gram-negative bacteria, fungi, actinomycetes, and yeasts. The active material was readily isolated from culture fluids of the organism by ether extraction or by adsorption on a resin. A high degree of purity was achieved chromatographically. Acetone, methanol, or aqueous solutions of the antibiotic were stable when stored at low temperature (4 °C). At 70 °C it was unstable in phosphate buffer but retained its activity in iris buffer at neutral and alkaline pH.

The Histidine Decarboxylase (HDC) Gene of Tetrahymena Pyriformis is Similar to the Mammalian One. A Study of HDC Expression

1999 ◽  
Vol 19 (2) ◽  
pp. 73-79 ◽  
Author(s):  
Hargita Hegyesi ◽  
Cs. Szalai ◽  
A. Falus ◽  
G. Csaba
Keyword(s):  
Histidine Decarboxylase ◽  
Tetrahymena Pyriformis ◽  
Unicellular Eukaryote ◽  
Rt Pcr ◽  
Base Pairs ◽  
Common Gene ◽  
Pcr Product ◽  
Evolutionary Level

RNA was isolated from Tetrahymena pyriformis GL and using human histidine decarboxylase (HDC) gene primers, the RT-PCR product was sequenced. A fraction containing 207 base pairs was compared to the published sequences of prokaryotic and mammalian (rat, mouse and human) HDC cDNA (exons). The HDC-cDNA fraction of Tetrahymena was similar to the mammalian cDNA-s and it was completely different from the prokaryotic HDC-gene. The results indicate the presence of a mammalian-like HDC-gene already in a unicellular eukaryote organism and demonstrates also that the divergence of the prokaryotic–eukaryotic common gene took place already at this low evolutionary level.

Demonstration of 2-Oxoglutarate:Glyoxylate Carboligase Activity in Tetrahymena pyriformis

1973 ◽  
Vol 51 (11) ◽  
pp. 1505-1508 ◽  
Author(s):  
Gloria Zaror-Behrens ◽  
C. Mavrides
Keyword(s):  
Tetrahymena Pyriformis ◽  
Mitochondrial Fraction ◽  
Heart Mitochondria ◽  
Thiamine Pyrophosphate ◽  
Beef Heart ◽  
Beef Heart Mitochondria ◽  
Oxoglutarate Dehydrogenase

A 2-oxoglutarate:glyoxylate carboligase, requiring thiamine pyrophosphate and magnesium, was demonstrated in Tetrahymena pyriformis and appears to be located in the mitochondrial fraction. The product of the reaction α-hydroxy-β-ketoadipate decarboxylates in the presence of acid to δ-hydroxylevulinate. The latter was identified in the acidified reaction mixtures. The carboligase activity varies coordinately with 2-oxoglutarate dehydrogenase. The two activities may reside in the same complex as in beef-heart mitochondria.

Regulation of Glyconeogenesis from Amino Acids by Acetate in Tetrahymena pyriformis

1973 ◽  
Vol 51 (4) ◽  
pp. 323-331 ◽  
Author(s):  
C. Mavrides
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Glutamate Dehydrogenase ◽  
Aspartic Acid ◽  
Growth Medium ◽  
Aspartate Aminotransferase ◽  
Alanine Aminotransferase ◽  
Sodium Acetate ◽  
Tetrahymena Pyriformis

The regulation of glyconeogenesis from amino acids by acetate was studied in Tetrahymena pyriformis. Alanine aminotransferase and glutamate dehydrogenase were repressed by 0.1% sodium acetate in the growth medium. Incorporations into the glycogen of washed cells from the respective isotopically labelled amino acids were similarly suppressed.Incorporations into glycogen from uniformly 14C-labelled L-serine, L-leucine, L-isoleucine, L-tyrosine, and DL-β-14C-tyrosine were also suppressed by prior growth in a medium supplemented with 0.1% or 0.3% acetate. Percentage incorporation into glycogen was highest from tyrosine, followed by leucine, isoleucine, and alanine, and lowest from glutamic acid and serine.Supplementation of the medium with 0.25% glucose resulted in repression of the above two enzymes and suppression of incorporation into glycogen from amino acids.Incorporation of aspartic acid into glycogen was negligible and was variously and minimally affected by growth in glucose- or acetate-supplemented media. Aspartate aminotransferase was affected in a like manner.Glycogen content was not significantly affected by growth in media supplemented with 0.1% or 0.3% acetate. On the whole, the data suggest that acetate spares amino acids for glyconeogenesis by a mechanism which entails repression of amino-acid-catabolizing enzymes.

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