Activités physiologiques de l'ochracine, synthétisée par Septoria nodorum, sur la croissance de plantules de riz et sur la synthèse ‘de novo’ des alpha-amylases par les couches à aleurone du caryopse de blé. Interaction avec l'acide gibbérellique

1979 ◽  
Vol 57 (6) ◽  
pp. 561-567 ◽  
Author(s):  
G. Touraud ◽  
J. F. Bousquet
Keyword(s):  
Synergistic Effect ◽  
Gibberellic Acid ◽  
De Novo ◽  
Pathogenic Fungus ◽  
Septoria Nodorum ◽  
De Novo Synthesis ◽  
Rice Seedlings ◽  
Culture Filtrates ◽  
Increased Sensitivity ◽  
Tissue Permeability

Ochracine was isolated from culture filtrates of Septoria nodorum Berk. (Berk.), a pathogenic fungus of wheat. At concentrations ranging from 25 μg/mL it inhibited the growth of wheat and rice seedlings and the 'de novo' synthesis of α-amylases by the aleurone layers of wheat. These effects were not reversed by increased concentrations of gibberellic acid.Between 2.5 and 10 μg/mL, ochracine exhibited a synergistic effect with exogenous gibberellic acid on the same physiological phenomena. For these last concentrations, the results suggest an increased sensitivity of rice seedlings and wheat aleurone layers to exogenous gibberellic acid as a result of changes in tissue permeability.

Screening of Basidiomycetes and Ascomycetes for Plant Growth Regulating Substances. Introduction of the Gibberellic Acid Induced de-novo Synthesis of Hydrolytic Enzymes in Embryoless Seeds of Triticum aestivum as Test System

1990 ◽  
Vol 45 (11-12) ◽  
pp. 1093-1098 ◽  
Author(s):  
Ralf Hautzel ◽  
Heidrun Anke
Keyword(s):  
Triticum Aestivum ◽  
Plant Growth ◽  
Gibberellic Acid ◽  
De Novo ◽  
Hydrolytic Enzymes ◽  
Test System ◽  
Active Principle ◽  
De Novo Synthesis ◽  
Plant Growth Regulating Substances

Abstract A new test system for the detection of plant growth regulating activities was successfully employed. In a screening for inhibitors of the gibberellic acid controlled synthesis of hydrolytic enzymes in embryoless wheat seeds (Triticum aestivum) 160 cultures of ascomycetes and basi­diomycetes were tested. In the extracts of two cultures inhibitory activities were detected. From fermentations of a Hypholoma-species (basidiomycetes) 3,5-dichloro-4-methoxybenzyl alcohol was isolated as the active principle. Galiellalactone and two other new phytotoxins were isolated from cultures of the ascomycete Galiella rufa. At concentrations of 50 μg/ml all four compounds inhibited the de-novo synthesis of α-amylases, proteases, and phosphatases. Further investigations on the mode of action revealed, that all four metabolites interfere with early steps of the biosynthetic path­ ways induced by gibberellic acids. In vivo, the germination of the seeds of several plants was inhibited by these compounds.

Barbiturate-induced α-amylase synthesis in barley endosperm

1970 ◽  
Vol 48 (11) ◽  
pp. 1981-1988 ◽  
Author(s):  
G. A. White
Keyword(s):  
Enzyme Activity ◽  
Gibberellic Acid ◽  
Barbituric Acid ◽  
De Novo ◽  
Carbonyl Oxygen ◽  
De Novo Synthesis ◽  
Barley Endosperm ◽  
Optimal Activity ◽  
Mammalian Liver ◽  
Kinetics Of

Phenobarbital has been found to promote the synthesis and secretion of α-amylase by embryoless barley seeds. Optimal activity was observed at a phenobarbital concentration of 1.0 mM, which promoted 39–82% (average, 57%) as much α-amylase formation as did saturating concentrations of gibberellic acid (GA3). Barley half-seeds incubated with 0.1 mM phenobarbital secreted as much protein as did those treated with 1.0 μM GA3. The kinetics of release of α-amylase from half-seeds incubated with either phenobarbital or GA3 appeared identical. Phenobarbital likely induces a de novo synthesis of α-amylase since the increase in enzyme activity was almost totally blocked by cycloheximide and 6-methylpurine. Besides phenobarbital, only cyclobarbital, amytal, hexobarbital, and thiopental showed activity among a large number of barbiturates and related drugs which were tested. In the phenobarbital molecule, the carbonyl oxygen at position 2 and the hydrogen on the nitrogen at position 3 of the barbituric acid ring are absolute requirements for activity since both 2-desoxyphenobarbital and methylphenobarbital elicited no response. Substitution of the phenyl moiety of phenobarbital with any group other than a cyclohexenyl (cyclobarbital) or an isoamyl (amytal) gave complete inactivity. Some possible mechanisms for the mode of action of phenobarbital in the barley endosperm system are discussed with particular reference to what is currently known regarding the inductive action of this barbiturate in mammalian liver.

Characterization of Monocyte-Associated Factor V

1993 ◽  
Vol 70 (02) ◽  
pp. 273-280 ◽  
Author(s):  
Janos Kappelmayer ◽  
Satya P Kunapuli ◽  
Edward G Wyshock ◽  
Robert W Colman
Keyword(s):  
Monoclonal Antibody ◽  
Light Chain ◽  
Peripheral Blood ◽  
De Novo ◽  
Factor V ◽  
Blood Monocytes ◽  
De Novo Synthesis ◽  
Hep G2 ◽  
Hep G2 Cells ◽  
Peripheral Blood Monocytes

SummaryWe demonstrate that in addition to possessing binding sites for intact factor V (FV), unstimulated peripheral blood monocytes also express activated factor V (FVa) on their surfaces. FVa was identified on the monocyte surface by monoclonal antibody B38 recognizing FVa light chain and by human oligoclonal antibodies H1 (to FVa light chain) and H2 (to FVa heavy chain) using immunofluorescence microscopy and flow cytometry. On Western blots, partially cleaved FV could be identified as a 220 kDa band in lysates of monocytes. In addition to surface expression of FVa, monocytes also contain intracellular FV as detected only after permeabilization by Triton X-100 by monoclonal antibody B10 directed specifically to the Cl domain not present in FVa. We sought to determine whether the presence of FV in peripheral blood monocytes is a result of de novo synthesis.Using in situ hybridization, no FV mRNA could be detected in monocytes, while in parallel control studies, factor V mRNA was detectable in Hep G2 cells and CD18 mRNA in monocytes. In addition, using reverse transcriptase and the polymerase chain reaction, no FV mRNA was detected in mononuclear cells or in U937 cells, but mRNA for factor V was present in Hep G2 cells using the same techniques. These data suggest that FV is present in human monocytes, presumably acquired by binding of plasma FV, and that the presence of this critical coagulation factor is not due to de novo synthesis.

Platelets Stimulate Thromboplastin Synthesis in Human Endothelial Cells

1983 ◽  
Vol 49 (02) ◽  
pp. 069-072 ◽  
Author(s):  
U L H Johnsen ◽  
T Lyberg ◽  
K S Galdal ◽  
H Prydz
Keyword(s):  
Endothelial Cells ◽  
De Novo ◽  
Umbilical Vein ◽  
Time Dependent ◽  
De Novo Synthesis ◽  
Human Endothelial Cells ◽  
Tumor Promotor ◽  
Coagulation Assay ◽  
Platelet Aggregates ◽  
Umbilical Vein Endothelial Cells

SummaryHuman umbilical vein endothelial cells in culture synthesize thromboplastin upon stimulation with phytohaemagglutinin (PHA) or the tumor promotor 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The thromboplastin activity is further strongly enhanced in a time dependent reaction by the presence of gel-filtered platelets or platelet aggregates. This effect was demonstrable at platelet concentrations lower than those normally found in plasma, it may thus be of pathophysiological relevance. The thromboplastin activity increased with increasing number of platelets added. Cycloheximide inhibited the increase, suggesting that de novo synthesis of the protein component of thromboplastin, apoprotein III, is necessary.When care was taken to remove monocytes no thromboplastin activity and no apoprotein HI antigen could be demonstrated in suspensions of gel-filtered platelets, platelets aggregated with thrombin or homogenized platelets when studied with a coagulation assay and an antibody neutralization technique.

DE NOVO SYNTHESIS OF STEROIDS BY THE TESTES OF THE HUMAN FOETUS AT MIDGESTATION

1971 ◽  
Vol 68 (1_Supplb) ◽  
pp. S135 ◽  
Author(s):  
R. S. Mathur ◽  
N. Wiqvist ◽  
E. Diczfalusy
Keyword(s):  
De Novo ◽  
De Novo Synthesis ◽  
Human Foetus
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