Benzyladenine accelerates chloroplast differentiation and stimulates photosynthetic enzyme activity in cucumber cotyledons

1974 ◽  
Vol 52 (12) ◽  
pp. 2581-2586 ◽  
Author(s):  
B. M. R. Harvey ◽  
B. C. Lu ◽  
R. A. Fletcher
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Enzyme Activities ◽  
Membrane System ◽  
Structural Differentiation ◽  
Specific Activities ◽  
Cucumber Cotyledons ◽  
Ribulose Diphosphate Carboxylase ◽  
Stimulation Of

The chloroplasts of etiolated cucumber cotyledons had crystalline prolamellar bodies, whereas those treated with benzyladenine (BA) have a well-developed plastid membrane system. After 4 h of exposure to light, grana were formed in the chloroplasts of BA-treated cotyledons but not in the controls. The specific activities of ribulose 1,5-diphosphate carboxylase, and NADP-dependent glyceraldehyde 3-phosphate dehydrogenase increased 75 and 50% respectively during BA treatment in the dark, while there was little change in the controls. On exposure to light, enzyme activities increased in both control and BA-treated cotyledons. Inhibitors of protein synthesis eliminated the BA stimulation of ribulose diphosphate carboxylase but had little effect on the BA stimulation of NADP-dependent glyceraldehyde 3-phosphate dehydrogenase activity. This study indicates that BA stimulates structural differentiation of the chloroplast and enhances activities of photosynthetic enzymes, even in the dark.

Spurious Elevation of Apparent Lactate Dehydrogenase Activity Caused by Triamterene

1973 ◽  
Vol 19 (10) ◽  
pp. 1202-1204 ◽  
Author(s):  
T Chainuvati ◽  
U Harinasuta ◽  
H J Zimmerman
Keyword(s):  
Enzyme Activity ◽  
Lactate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Enzyme Activities ◽  
Physiological Saline ◽  
Serum Lactate ◽  
Normal Serum ◽  
Serum Lactate Dehydrogenase ◽  
Fluorometric Method ◽  
Lactate Dehydrogenase Activity

Abstract Triamterene induced spurious elevations in serum lactate dehydrogenase activity, as assayed by an automated fluorometric method; the enzyme activities were normal when measured spectrophotometrically. Solutions of the drug in normal serum or physiological saline, without addition of substrate or coenzyme, yielded high values for apparent "enzyme" activity by the fluorometric assay.

scholarly journals Dehydrogenase Activity in a Litter Manipulation Experiment in Temperate Forest Soil

2013 ◽  
Vol 9 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Zsuzsa Veres ◽  
Zsolt Kotroczó ◽  
Kornél Magyaros ◽  
János Attila Tóth ◽  
Béla Tóthmérész
Keyword(s):  
Enzyme Activity ◽  
Microbial Activity ◽  
Dehydrogenase Activity ◽  
Enzyme Activities ◽  
Soil Microbial Activity ◽  
Litter Production ◽  
Labile Carbon ◽  
Soil Microbial ◽  
Litter Manipulation ◽  
Soil Dehydrogenase Activity

Abstract Soil enzyme activities are “sensors” of soil organic matter (SOM) decomposition since they integrate information about microbial status and physico-chemical condition of soils. We measured dehydrogenase enzyme activity in a deciduous temperate oak forest in Hungary under litter manipulation treatments. The Síkfőkút Detritus Input and Removal Treatments (DIRT) Project includes treatments with doubling of leaf litter and woody debris inputs as well as removal of leaf litter and trenching to prevent root inputs. We hypothesized that increased detrital inputs increase labile carbon substrates to soils and would increase enzyme activities particularly that of dehydrogenase, which has been used as an indicator of soil microbial activity. We also hypothesized that enzyme activities would decrease with detritus removal plots and decrease labile carbon inputs to soil. After ten years of treatments, litter removal had a stronger effect on soil dehydrogenase activity than did litter additions. These results showed that in this forest ecosystem the changed litter production affected soil microbial activity: reduced litter production decreased the soil dehydrogenase activity; increased litter production had no significant effect on the enzyme activity.

EFFECT OF HUMAN CHORIONIC GONADOTROPHIN ON TESTICULAR 5α-ANDROSTANE-3β-HYDROXYSTEROID DEHYDROGENASE, 3β-HYDROXYDEHYDROEPIANDROSTERONE DEHYDROGENASE AND ALCOHOL DEHYDROGENASE OF IMMATURE RATS

1973 ◽  
Vol 57 (3) ◽  
pp. 437-449 ◽  
Author(s):  
JOACHIM FROWEIN
Keyword(s):  
Alcohol Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Enzyme Activities ◽  
Hydroxysteroid Dehydrogenase ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Alcohol Dehydrogenase Activity ◽  
Immature Rats ◽  
Specific Activities ◽  
Androgenic Steroids

SUMMARY Testicular enzymes related to steroid conversion were studied in infantile rats during sexual maturation, and the effect of human chorionic gonadotrophin (HCG) on the specific activities of the enzymes was analysed. Activity of 5α-androstane-3β-hydroxysteroid dehydrogenase, which increases between days 20 and 30, was markedly enhanced after administration of HCG. Alcohol dehydrogenase activity, which is related to 3β-hydroxysteroid dehydrogenase activity, also increased after HCG treatment. The other enzyme activities investigated, i.e. 3β-hydroxyde-hydroepiandrosterone dehydrogenase and testosterone-17β-dehydrogenase, did not respond to HCG administration. These results suggest that different enzymes are responsible for the conversion of 3β-hydroxylated androgenic steroids and that the testicular alcohol dehydrogenase is not identical to the 3β-hydroxysteroid dehydrogenase described here. On the assumption that HCG enhances enzyme activities indirectly by stimulating the synthesis of androgens which in turn produce the observed effect, different androgenic steroids (epiandrosterone, 5α-androstane-3,17-dione, 5α-dihydrotestosterone, 5α-androstane-3β,17β-diol) were tested for their ability to increase enzyme activities. None of these metabolites had an effect similar to that of HCG. The antiandrogen cyproterone (1,2α-methyl-6-chloro Δ4,6-pregnadien-17β-ol-3,20-dione) acetate, which was administered simultaneously with HCG, did not prevent the effect of HCG. From these results and other published reports it is concluded that in the testis of the infantile rat the metabolism of 5α-hydrogenated androgenic metabolites is stimulated by HCG.

THE INFLUENCE OF HAEMOGLOBIN-S AND G6PD DEFICIENCY ON THE ACTIVITY OF THE 17β-HYDROXYSTEROID DEHYDROGENASE OF INTACT HUMAN ERYTHROCYTES

1974 ◽  
Vol 75 (4) ◽  
pp. 793-800
Author(s):  
A. O. Sogbesan ◽  
O. A. Dada ◽  
B. Kwaku Adadevoh
Keyword(s):  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Sex Steroids ◽  
G6pd Deficiency ◽  
Incubation Medium ◽  
Hydroxysteroid Dehydrogenase ◽  
G6pd Activity ◽  
Reverse Transformation ◽  
Oxidative Transformation ◽  
Haemoglobin S

ABSTRACT The 17β-hydroxysteroid dehydrogenase activity in intact erythrocytes of Nigerian patients, in particular with regard to haemoglobin genotypes and G6PD* activity was studied. The G6PD activity of the erythrocyte did not affect the oxidative transformation of testosterone to androstenedione and of oestradiol to oestrone. The reduction (reverse transformation) was inhibited in G6PD-deficient erythrocytes but this inhibition was offset by the addition of 0.025 m glucose to the incubation medium. The per cent oxidation transformation of testosterone was higher in Hb-AA than in Hb-SS erythrocytes. It is suggested that the differences may be a result of either lower enzyme activity in the Hb-SS erythrocytes or of differences in the uptake and possibly binding of sex steroids by intact Hb-SS and Hb-AA erythrocytes.

EFFECT OF ACTINOMYCIN D ON TSH-INDUCED STIMULATION OF THYROIDAL PROTEIN SYNTHESIS IN THE RAT

1974 ◽  
Vol 77 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Gustav Wägar
Keyword(s):  
Protein Synthesis ◽  
Actinomycin D ◽  
The Other ◽  
Leucine Incorporation ◽  
Short Term ◽  
Other Hand ◽  
Thyroid Glands ◽  
Translational Level ◽  
Stimulation Of

ABSTRACT Whether the short-term regulation of thyroidal protein synthesis by TSH occurs at the transcriptional or the translational level was tested by measuring the effect of actinomycin D (act D) on the TSH-induced stimulation of L-14C-leucine incorporation into the thyroidal proteins of rats. TSH was injected 6 h before the rats were killed. The thyroid glands were then removed and incubated in vitro in the presence of L-14C-leucine for 2 h. The pronounced stimulation of leucine incorporation in the TSH-treated animals was depressed as compared with controls but still significant even when the animals had been pre-treated with 100 μg act D 24 and 7 h before sacrifice. On the other hand, act D strongly decreased incorporation of 3H-uridine into RNA. Short-term regulation of thyroidal protein synthesis by TSH appears to be partly but not wholly dependent on neosynthesis of RNA. Hence regulation may partly occur at the translation level of protein synthesis.

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