Stimulation of Phenylalanine Incorporation in Hepatic Polyribosome Preparations by Polyuridylic Acid

Nature ◽  
1966 ◽  
Vol 209 (5029) ◽  
pp. 1204-1206 ◽  
Author(s):  
H. BLOEMENDAL ◽  
W. S. BONT ◽  
I. MEISNER
Keyword(s):  
Polyuridylic Acid ◽  
Stimulation Of

scholarly journals Stimulation of Antibacterial Vaccination in Mice by Polyadenylic Acid: Polyuridylic Acid Complex

1972 ◽  
Vol 6 (5) ◽  
pp. 699-702 ◽  
Author(s):  
Gérard Renoux ◽  
Micheline Renoux ◽  
Robert Branche
Keyword(s):  
Acid Complex ◽  
Polyadenylic Acid ◽  
Polyuridylic Acid ◽  
Stimulation Of

scholarly journals Stimulation of peptide elongation by thyroxine

1976 ◽  
Vol 156 (3) ◽  
pp. 713-717 ◽  
Author(s):  
W J Carter ◽  
F H Faas ◽  
J O Wynn
Keyword(s):  
Peptide Bond ◽  
Conclusive Evidence ◽  
Chain Elongation ◽  
Synthesis System ◽  
Polyuridylic Acid ◽  
A Cell ◽  
Peptide Elongation ◽  
Trna Binding ◽  
Protein Synthesis System ◽  
Stimulation Of

This study suggests that thyroxine stimulates peptide elongation in a cell-free rat liver polyribosome system. The thyroxine effect persists in the presence of sufficient aurintricarboxylic acid to prevent polyuridylic acid-stimulated peptide initiation. In addition, thyroxine stimulates elongation of pre-existing polyphenylalanine chains providing conclusive evidence that the effect does not depend on peptide initiation. Thyroxine does not stimulate release of nascent peptides from ribosomes into the supernatant phase of the reaction mixture. Therefore in this protein-synthesis system the thyroxine effect is expected to occur at one or more of the reactions of peptide chain elongation, which include aminoacyl-tRNA binding, peptide bond synthesis and translocation.

scholarly journals Further observations on the polynucleotide-induced stimulation of protein synthesis by cell-free preparations from rabbit reticulocytes

1965 ◽  
Vol 97 (2) ◽  
pp. 595-606 ◽  
Author(s):  
KG Nair ◽  
HRV Arnstein
Keyword(s):  
Protein Synthesis ◽  
Messenger Rna ◽  
Free System ◽  
Cell Free System ◽  
Polyadenylic Acid ◽  
Polyuridylic Acid ◽  
Optimum Response ◽  
Ph Range ◽  
Rabbit Reticulocytes ◽  
Stimulation Of

1. The effect of high-molecular-weight RNA from reticulocyte polyribosomes (messenger RNA) on protein synthesis by subcellular fractions derived from reticulocytes, reported by Arnstein, Cox & Hunt (1964), has now been studied in detail. Optimum response of the cell-free system requires 30-50mm-K(+) and approx. 5mm-Mg(2+) in the pH range 7.4-7.6. 2. RNA stimulates the incorporation into protein of both free amino acids and of aminoacyl residues from s-RNA. Stimulation by either RNA or polyuridylic acid is dependent on a labile factor or enzyme, which is present in the; pH5 fraction' and may be concerned with the formation of new polysomes. Quantitatively the response of the cell-free system to RNA is similar to that of polyuridylic acid, and there appears to be competition between messenger RNA and polyuridylic acid or polyadenylic acid.

Effects of 5-5'-Diphenyl-2-thiohydantoin (DPTH) and Thyroxine on the Ultrastructure and Chemical Composition of Rat Liver

1971 ◽  
Vol 29 ◽  
pp. 570-571
Author(s):  
E. A. Elfont ◽  
R. B. Tobin ◽  
D. G. Colton ◽  
M. A. Mehlman
Keyword(s):  
Chemical Composition ◽  
Rat Liver ◽  
Future Study ◽  
Mode Of Action ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Effective Inhibitor ◽  
Biochemical Effects ◽  
Glycerophosphate Dehydrogenase ◽  
Stimulation Of

Summary5,-5'-diphenyl-2-thiohydantoin (DPTH) is an effective inhibitor of thyroxine (T4) stimulation of α-glycerophosphate dehydrogenase in rat liver mitochondria. Because this finding indicated a possible tool for future study of the mode of action of thyroxine, the ultrastructural and biochemical effects of DPTH and/or thyroxine on rat liver mere investigated.Rats were fed either standard or DPTH (0.06%) diet for 30 days before T4 (250 ug/kg/day) was injected. Injection of T4 occurred daily for 10 days prior to sacrifice. After removal of the liver and kidneys, part of the tissue was frozen at -50°C for later biocheailcal analyses, while the rest was prefixed in buffered 3.5X glutaraldehyde (390 mOs) and post-fixed in buffered 1Z OsO4 (376 mOs). Tissues were embedded in Araldlte 502 and the sections examined in a Zeiss EM 9S.Hepatocytes from hyperthyroid rats (Fig. 2) demonstrated enlarged and more numerous mitochondria than those of controls (Fig. 1). Glycogen was almost totally absent from the cytoplasm of the T4-treated rats.

Gap junctions in the prothoracic glands of the tobacco hornworm, Manduca sexta

1992 ◽  
Vol 50 (1) ◽  
pp. 706-707
Author(s):  
Ji-da Dai ◽  
M. Joseph Costello ◽  
Lawrence I. Gilbert
Keyword(s):  
Gap Junctions ◽  
Small Molecules ◽  
Manduca Sexta ◽  
Freeze Fracture ◽  
Cell Communication ◽  
Cellular Level ◽  
Thin Sections ◽  
Prothoracic Glands ◽  
Polyhydroxylated Steroids ◽  
Stimulation Of

Insect molting and metamorphosis are elicited by a class of polyhydroxylated steroids, ecdysteroids, that originate in the prothoracic glands (PGs). Prothoracicotropic hormone stimulation of steroidogenesis by the PGs at the cellular level involves both calcium and cAMP. Cell-to-cell communication mediated by gap junctions may play a key role in regulating signal transduction by controlling the transmission of small molecules and ions between adjacent cells. This is the first report of gap junctions in the PGs, the evidence obtained by means of SEM, thin sections and freeze-fracture replicas.

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