Reversible Inhibition of RNA Synthesis in Tetrahymena pyriformis GL by Dimethyl Sulphoxide: An Electron Microscope Autoradiographic Study

1976 ◽  
Vol 95 (3) ◽  
pp. 403 ◽  
Author(s):  
Jytte R. Nilsson
Keyword(s):  
Electron Microscope ◽  
Rna Synthesis ◽  
Tetrahymena Pyriformis ◽  
Autoradiographic Study ◽  
Dimethyl Sulphoxide ◽  
Reversible Inhibition

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 Electron microscope autoradiographic study of intestinal absorption of decanoic and octanoic acids in the rat.

1975 ◽  
Vol 65 (2) ◽  
pp. 383-397 ◽  
Author(s):  
H Carlier ◽  
J Bezard
Keyword(s):  
Fatty Acids ◽  
Electron Microscope ◽  
Intestinal Absorption ◽  
Common Duct ◽  
Autoradiographic Study ◽  
Electron Microscope Autoradiography ◽  
Blood Capillaries ◽  
Medium Chain ◽  
Medium Chain Fatty Acids ◽  
Chain Fatty Acids

Intestinal absorption of [3H]octanoic acid and [3H]decanoic acid was investigated in the rat by electron microscope autoradiography. The common duct (bile and pancreatic common duct) of the rats was diverted and a loop of the duodenum was cannulated 24 h later. The lipid mixture to be investigated was introduced into each experimental loop, and after 15 min or less the loop was removed. One part of each loop was used to determine the distribution of radioactivity in different lipid fractions, and an autoradiographic study was performed on the other part of the loop. Radioactivity distribution studies confirmed that medium chain fatty acids are absorbed in their nonesterified form and established that these fatty acids are absorbed much more rapidly than oleic acid. Autoradiographic studies indicated that the medium chain fatty acids are taken up in a molecular or aggregate molecular form, leave the epithelial cells by way of the lateral plasma membrane, and are next found in the blood capillaries. Our results suggest that the Golgi complex does not play an important role in the absorption of unesterified fatty acids.

Sign in / Sign up

Export Citation Format

Share Document