scholarly journals THE EFFECT OF CHANGES IN THE RESPIRATORY METABOLISM UPON GENOME ACTIVITY

1972 ◽  
Vol 55 (2) ◽  
pp. 257-265 ◽  
Author(s):  
Hans J. Leenders ◽  
Pieter J. A. Beckers
Keyword(s):  
Enzyme Activity ◽  
Salivary Glands ◽  
Actinomycin D ◽  
Maximum Size ◽  
Respiratory Metabolism ◽  
Maximum Increase ◽  
Drosophila Hydei ◽  
Nicotinamide Adenine Dinucleotide Dehydrogenase ◽  
Genome Activity

The in vitro regression of experimentally induced chromosome puffs was investigated in explanted salivary gland chromosomes of Drosophila hydei. It was observed that the regression of the puffs 2-32A, 2-36A, 2-48C, and 4-81B is accelerated if substrates for the respiratory metabolism are supplied to the cells. A similar effect can be produced by addition of KCN or oligomycin to medium in which intact salivary glands are incubated. The acceleration of puff regression by these substances occurs not only if the puff-inducing stimulus is removed but as well under conditions in which the stimulus is maintained. Regression of the puffs 2-32A, 2-36A, and 4-81B is inhibited if cycloheximide is present in the incubation medium. Chloramphenicol has no effect on puff regression. Measurements on nicotinamide adenine dinucleotide-dehydrogenase activity in homogenates of salivary glands revealed an increase in enzyme activity of 41 %. Maximum increase is attained at 30 min after the induced puffs have reached their maximum size. The increase in enzyme activity does not occur if the glands are kept in a medium containing either actinomycin D or cycloheximide. Chloramphenicol does not inhibit the increase in enzyme activity. The possible relationship between puff activity and its control as a result of changes in the respiratory metabolism is discussed.

Properties of Na, K-ATPase from the salivary glands of the ixodid tick Amblyomma hebraeum

1980 ◽  
Vol 58 (6) ◽  
pp. 1052-1059 ◽  
Author(s):  
B. Rutti ◽  
B. Schlunegger ◽  
W. Kaufman ◽  
A. Aeschlimann
Keyword(s):  
Enzyme Activity ◽  
Salivary Glands ◽  
Fluid Secretion ◽  
Ixodid Tick ◽  
Rich Source ◽  
Amblyomma Hebraeum ◽  
Fundamental Properties ◽  
High Concentrations

Tick (Amblyomma hebraeum) salivary glands are a rich source of Na,K-ATPase (EC 3.6.1.3), the fundamental properties of which are similar to those of Na,K-ATPases from other sources. Inhibition of the enzyme by ouabain is quantitatively similar to the inhibition of fluid secretion by this drug. Harmaline at high concentrations also inhibited the Na,K-ATPase. The nucleotides GTP, ITP, and UTP were utilized as substrates, but all were less effective than ATP. Noradrenaline, dopamine, and phenoxybenzamine, all at concentrations known to influence fluid secretion in vitro, had no effect on enzyme activity.

THE DEVELOPMENT OF AN IN VITRO SYSTEM FOR ESTIMATING OXYTOCINASE IN THE RABBIT HYPOTHALAMUS AND THE EFFECTS OF SOME PROTEIN SYNTHESIS INHIBITORS AND OESTRADIOL-17β ON ENZYME ACTIVITY

1974 ◽  
Vol 75 (3) ◽  
pp. 443-451 ◽  
Author(s):  
Dona A. Frith ◽  
K. C. Hooper
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Steroid Hormones ◽  
Actinomycin D ◽  
Protein Synthesis Inhibitors ◽  
In Vitro System

ABSTRACT An in vitro system for investigating the effects of steroid hormones and protein synthesis inhibitors on hypothalamic peptidases inactivating oxytocin has been developed. In the presence of oestradiol-17β enzyme activity was increased in the in vitro system whilst this increase was blocked completely by cycloheximide and partially blocked by actinomycin-D. It is apparent therefore that oestradiol-17β acts directly on the hypothalamus stimulating oxytocinase activity.

THE EFFECT OF OESTRADIOL-17β ON ENZYMES CONCERNED WITH METABOLISM OF CARBOHYDRATE IN HUMAN ENDOMETRIUM IN VITRO

1969 ◽  
Vol 44 (1) ◽  
pp. 63-NP ◽  
Author(s):  
E. W. WILSON
Keyword(s):  
Enzyme Activity ◽  
Actinomycin D ◽  
Human Endometrium ◽  
Enzyme Protein ◽  
Quantitative Histochemistry ◽  
Qualitative And Quantitative ◽  
Hormonal Effect ◽  
Lactate Dehydrogenases ◽  
Regenerative Phase

SUMMARY Human endometrium in the regenerative phase was maintained for 5 hr. in vitro with oestradiol-17β alone or together with actinomycin D. Qualitative and quantitative histochemistry of the tissue showed that the activities of glucose-6-phosphate, 6-phosphogluconate, and lactate dehydrogenases were increased by oestradiol, and that actinomycin suppressed the hormonal effect. The activities of succinate and iso-citrate dehydrogenases were unaffected by oestradiol. An attempt is made to correlate the metabolic roles of the enzymes affected by oestradiol. The suppression, by actinomycin, of the oestradiol effect suggests that the increased enzyme activity is due to the formation of new enzyme protein.

DNA-dependent RNA polymerase from Pseudomonas aeruginosa

1987 ◽  
Vol 65 (9) ◽  
pp. 776-782 ◽  
Author(s):  
Brenda Allan ◽  
Andrew M. Kropinski
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Enzyme Activity ◽  
Rna Polymerase ◽  
Actinomycin D ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Subunit Structure ◽  
Partial Activity ◽  
Inhibited Enzyme

DNA-dependent RNA polymerase was purified from Pseudomonas aeruginosa. The subunit structure was typical of other eubacterial RNA polymerases in having β′ (157 000), β (148 000), σ (87 000), and α2 (45 000) subunits as determined by sodium dodecyl sulfate–polyacrylamide gel electrophoresis. The enzyme was dependent on Mg2+, displaying optimal activity at 10 mM MgCl2. Ca2+ and Zn2+ could not replace MgCl2 in the assay system, while Mn2+ produced partial activity. KCl at concentrations greater than 10 mM inhibited enzyme activity. Optimal enzyme activity was observed at pH 8.5–9.0. The RNA polymerase was stable in 50% (w/v) glycerol at 4 °C for more than 3 months. Enzyme activity was inhibited in vitro by heparin, streptolydigin, streptovaracin, actinomycin D, and rifampicin.

scholarly journals The effects of salicylate on the activity of rat liver tryptophan pyrrolase in vitro and in vivo

1971 ◽  
Vol 123 (2) ◽  
pp. 171-174 ◽  
Author(s):  
A. A.-B. Badawy ◽  
M. J. H. Smith
Keyword(s):  
Enzyme Activity ◽  
Rat Liver ◽  
Binding Sites ◽  
Actinomycin D ◽  
Sodium Salicylate ◽  
Progressive Increase ◽  
Tryptophan Pyrrolase ◽  
Enzyme Ratio

1. Salicylate, in concentrations of 0.05mm and above, inhibits the basal activity of tryptophan pyrrolase in homogenates of rat liver and the activity induced by cortisol but not that induced by tryptophan. The inhibition is abolished by adding haematin to the reaction mixtures. 2. The intraperitoneal injection of 400mg of sodium salicylate/kg in the rat causes a decrease in the tryptophan pyrrolase activity in the liver at 30min, the activity is restored to normal at 2h, increases to sixfold after 5h and returns to the basal value at 12h. The activation of the enzyme by salicylate is prevented by the administration of cycloheximide but not by pretreatment with actinomycin D. The effects of the combined injection of salicylate and cortisol are additive, whereas those of salicylate plus tryptophan are not. The injection of salicylate causes a progressive increase in the holo-/apo-enzyme ratio and an increased content of tryptophan in the liver over a period of 3h. 3. It is suggested that salicylate inhibits tryptophan pyrrolase activity in vitro and in vivo by interacting with iron protoporphyrins and causes a later enhancement of the enzyme activity in vivo by a mechanism involving the release of tryptophan from its binding sites on circulating albumin and on other proteins.

scholarly journals Increase in Lipoxygenase Activity in Hairy Roots of Ambrosia maritima after Elicitation with Methyl Jasmonate

2013 ◽  
Vol 23 (1) ◽  
Author(s):  
Sameh AbouZid ◽  
Yutaka Orihara
Keyword(s):  
Enzyme Activity ◽  
Methyl Jasmonate ◽  
Hairy Roots ◽  
Propyl Gallate ◽  
Time Course ◽  
Lipoxygenase Activity ◽  
Lipoxygenase Inhibitor ◽  
Maximum Increase

Hairy roots of Ambrosia maritima L. were cultured in MS in the dark. Time course production was studied for pentayneene and thiarubine A after addition of 40 ?M methyl jasmonate to the 13?day?old hairy roots. The levels of pentayneene and thiarubrine A showed maximum increase after 72 hrs adding methyl jasmonate. Lipoxygenase activity was increased in the hairy roots elicited with 40 ?M methyl jasmonate. The increase in activity was 28?fold higher than control cultures 24 hrs after elicitor addition. The increase in enzyme activity was concomitant with the increase in pentayeneene, the precursor for polyacetylene biosynthesis. N?propyl gallate, a potent in vivo and in vitro lipoxygenase inhibitor, reduced polyacetylene production by the hairy roots at concentration of 100 ?M. It is suggested that lipoxygenase may be at least partially involved in polyacetylene biosynthesis in A. maritima hairy roots.Plant Tissue Cult. & Biotech. 23(1): 31?38, 2013 (June)DOI: http://dx.doi.org/10.3329/ptcb.v23i1.15557

ANALYSIS OF THE BIPHASIC ACTION OF GROWTH HORMONE IN VITRO ON THE RAT DIAPHRAGM

1968 ◽  
Vol 57 (3_Suppl) ◽  
pp. S19-S35 ◽  
Author(s):  
Å. Hjalmarson
Keyword(s):  
Growth Hormone ◽  
Actinomycin D ◽  
Accumulation Rate ◽  
Inhibitory Effect ◽  
Bovine Growth Hormone ◽  
Rat Diaphragm ◽  
Dual Nature ◽  
Hypophysectomized Rats ◽  
D 20

ABSTRACT In vitro addition of bovine growth hormone (GH) to intact hemidiaphragms from hypophysectomized rats has previously been found to produce both an early stimulatory effect lasting for 2—3 hours and a subsequent late inhibitory effect during which the muscle is insensitive to further addition of GH (Hjalmarson 1968). These effects on the accumulation rate of α-aminoisobutyric acid (AIB) and D-xylose have been further studied. In presence of actinomycin D (20 μg/ml) or puromycin (100 μg/ml) the duration of the stimulatory effect of GH (25 μg/ml) was prolonged to last for at least 4—5 hours and the late inhibitory effect was prevented. Similar results were obtained when glucose-free incubation medium was used. Preincubation of the diaphragm at different glucose concentrations (0—5 mg/ml) for 3 hours did not change the GH sensitivity. Addition of insulin at start of incubation could not prevent GH from inducing its late inhibitory effect, while dexamethasone seemed to potentiate this effect of GH. Furthermore, adrenaline was found to decrease the uptake of AIB-14C and D-xylose-14C in the diaphragm, but not to change the sensitivity of the muscle to GH. Preincubation of the diaphragm for 3 hours with puromycin in a concentration of 200 μg/ml markedly decreased the subsequent basal uptake of both AIB-14C and D-xylose-14C, in the presence of puromycin, and abolished the stimulatory effect of GH on the accumulation of AIB-14C. However, the effect of GH on the accumulation of D-xylose-14C was unchanged. The present observations are discussed and evaluated in relation to various mechanisms of GH action proposed to explain the dual nature of the hormone.

CONTRIBUTION TO THE EXISTENCE OF REGULATORY MECHANISMS AT THE ADRENAL LEVEL

1972 ◽  
Vol 70 (4) ◽  
pp. 741-757
Author(s):  
Otto Linèt
Keyword(s):  
Orotic Acid ◽  
Adrenal Glands ◽  
Actinomycin D ◽  
Delay Period ◽  
Regulatory Mechanisms ◽  
Leucine Incorporation ◽  
Total Period ◽  
Free Media

ABSTRACT Rat adrenal glands atrophied by the administration of cortisol acetate in vivo were used as a model for the study of early metabolic processes occurring in vitro. Atrophied adrenals incubated in the presence of 14C-leucine incorporated subnormal quantities of this amino acid per mg of protein for the first 120 min. When the incubation lasted for a total period of 180 or 240 min a supranormal rise in the 14C-leucine incorporation was observed. Similar changes occurred with some delay with regard to corticosterone production as expressed per 100 mg of tissue. No differences in 14C-leucine incorporation were observed between the control and atrophied adrenals in vivo. Homogenates from atrophied glands incorporated 14C-leucine to a greater extent than the control homogenates. The in vitro incorporation of 14C-orotic acid into the RNA was also higher in atrophied adrenals. The in vitro use of actinomycin D, cycloheximide and amphenone indicated that corticosterone production depended on the incorporation of 14C-leucine. The addition of cortisol to the incubation media markedly decreased the enhancement of 14C-lysine incorporation into the protein of atrophied adrenals. These, as well as additional results suggest rebound phenomena: once atrophic adrenals are transferred to cortisol-free media, reparative processes begin after a delay period. Such phenomena seem to be mediated by regulatory mechanisms at the adrenal level.

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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