scholarly journals Isolation of chick intestinal nuclei. Effect of vitamin D3 on nuclear metabolism

1969 ◽  
Vol 115 (2) ◽  
pp. 263-268 ◽  
Author(s):  
D. E. M. Lawson ◽  
P. W. Wilson ◽  
D. C. Barker ◽  
E. Kodicek
Keyword(s):  
Vitamin D ◽  
Orotic Acid ◽  
Polymerase Activity ◽  
Vitamin D Status ◽  
Isolated Nuclei ◽  
Whole Cells ◽  
Nuclear Rna ◽  
Rna Polymerase Activity ◽  
Lag Period ◽  
Stimulation Of

1. Chick intestinal nuclei were isolated, with practically no contamination from other organelles and whole cells, by centrifugation through 2·4m-sucrose. 2. The proportions of RNA, DNA and protein of the isolated nuclei were unaffected by the vitamin D status of the birds. The RNA/DNA ratio was 0·15. 3. The incorporation of [5−3H]orotic acid into the rapidly labelled intestinal nuclear RNA, after a 10min. pulse of the orotic acid, was increased in vitamin D-deficient chicks only 10min. after a 125μg. dose of cholecalciferol. 4. There was no stimulation of the DNA-dependent RNA polymerase activity of the isolated nuclei from birds treated with cholecalciferol. 5. The results are discussed in relation to the changes occurring during the lag period, after administration of cholecalciferol and before Ca2+ transport is detected, and the function of the vitamin.

scholarly journals Inhibition of hepatic deoxyribonucleic acid-dependent ribonucleic acid polymerases by the exotoxin of Bacillus thuringiensis in comparison with the effects of α-amanitin and cordycepin

1972 ◽  
Vol 129 (1) ◽  
pp. 153-166 ◽  
Author(s):  
Edward A. Smuckler ◽  
Asen A. Hadjiolov
Keyword(s):  
Bacillus Thuringiensis ◽  
Rna Polymerase ◽  
Competitive Inhibition ◽  
Polymerase Activity ◽  
Rna Polymerases ◽  
Similar Action ◽  
Isolated Nuclei ◽  
Nuclear Rna ◽  
Rna Polymerase Activity

The action of Bacillus thuringiensis exotoxin, a structural analogue of ATP, on mouse liver DNA-dependent RNA polymerases was studied and its effects were compared with those of α-amanitin and cordycepin. (1) Administration of exotoxin in vivo caused a marked decrease in RNA polymerase activity of isolated nuclei at various concentrations of Mg2+, Mn2+and (NH4)2SO4. A similar action was recorded after addition of exotoxin to isolated nuclei from control or exotoxin-treated mice. (2) Chromatographic separation of nuclear RNA polymerases from mice treated in vivo with exotoxin showed a drastic decrease of the peak of nucleoplasmic RNA polymerase, whereas the peak of nucleolar RNA polymerase remained unaltered. The same effect was observed after administration of α-amanitin in vivo, but cordycepin did not alter the relative amounts of the two main RNA polymerase peaks. (3) Administration of exotoxin in vivo did not alter the template activity of isolated DNA or chromatin tested with different fractions of RNA polymerase from control or exotoxin-treated mice. (4) Addition of exotoxin to isolated liver RNA polymerases inhibited both enzyme fractions. However, the α-amanitin-sensitive RNA polymerase was also 50–100-fold more sensitive to exotoxin inhibition than was the α-amanitin-insensitive RNA polymerase. Kinetic analysis indicated the exotoxin produces a competitive inhibition with ATP on the nucleolar enzyme, but a mixed type of inhibition with nucleoplasmic enzyme. The results obtained indicate that the B. thuringiensis exotoxin inhibits liver RNA synthesis by affecting nuclear RNA polymerases, showing a preferential inhibition of the nucleoplasmic α-amanitin-sensitive RNA polymerase.

Stimulation of Protein Synthesis and of RNA Polymerase Activity in the Liver of 3-Methylcholanthrene-Treated Rats

1973 ◽  
Vol 59 (2) ◽  
pp. 119-127
Author(s):  
Claudia Greco ◽  
Umberto Ferrini
Keyword(s):  
Protein Synthesis ◽  
Single Dose ◽  
Rna Polymerase ◽  
Rat Liver ◽  
Transport Mechanism ◽  
Polymerase Activity ◽  
Isolated Nuclei ◽  
Rna Polymerase Activity ◽  
Stimulation Of

Following a single dose of 3-methylcholanthrene in rat liver the RNA polymerase activity of Mg++ and Mn++/(NH4)2SO4 - dependent forms is stimulated in isolated nuclei and particularly in the chromatin of extranucleolar fraction. The early enhancement of N-2-fluorenylacetamide microsomal hydroxylating activity does not parallel the shift of the monomer-polysome equilibrium to more aggregated forms. It is suggested that the rate of synthesis and the transport mechanism of RNA messengers into the cytoplasm can be selectively regulated by 3-methylcholanthrene and its metabolites.

scholarly journals Assessment of Vitamin D Status in Patients Suffering from Uncomplicated Malaria in a Health Center in the District of Abidjan (Côte d’Ivoire)

2021 ◽  
pp. 10-17
Author(s):  
Brice Kouakou Bla ◽  
Alexis Gnogbo Bahi ◽  
Juliana Mensah-Akaki ◽  
Souleymane Méité ◽  
Françis Adou Yapo ◽  
...  
Keyword(s):  
Vitamin D ◽  
Parasite Density ◽  
Uncomplicated Malaria ◽  
Parasite Species ◽  
Complete Blood Count ◽  
Vitamin D Status ◽  
25 Oh Vitamin D ◽  
Stimulation Of

Aims: The pathophysiology of Plasmodium falciparum infection is most often associated with anemia and immune deficiency. Given the important role of vitamin D in the synthesis of hemoglobin and in the stimulation of the immune system, it would be essential to assess the vitamin D status of patients with malaria in order to improve the quality of treatment management. Methodology: A thick drop and a blood smear were used to determine parasite density and parasite species respectively. The complete blood count was performed using an automated analyzer labelled Sysmex XN 1000i. Biochemical parameters such as calcium and phosphorus were determined using the Cobas C311 Hitachi. The Vidas was used to determine the concentrations of 25 (OH) -vitamin D. Results: The results showed a decrease in 25 (OH) -vitamin D concentrations in relation to the parasite density and anemia observed in patients with uncomplicated malaria. Conclusion: Vitamin D status in patients with uncomplicated malaria could represent an essential biomarker in the monitoring of antimalarial treatment.

Bone changes due to pregnancy and lactation: influence of vitamin D status

1986 ◽  
Vol 251 (4) ◽  
pp. E400-E406 ◽  
Author(s):  
P. J. Marie ◽  
L. Cancela ◽  
N. Le Boulch ◽  
L. Miravet
Keyword(s):  
Vitamin D ◽  
Bone Resorption ◽  
Bone Formation ◽  
Trabecular Bone ◽  
Formation Rate ◽  
Vitamin D Status ◽  
Bone Formation Rate ◽  
Bone Calcium ◽  
Pregnancy And Lactation ◽  
Stimulation Of

The effects of pregnancy and lactation on endosteal bone formation and resorption were evaluated in vitamin D-depleted (-D) and vitamin D-repleted (+D) rats. Pregnancy induced a marked stimulation of osteoclastic bone resorption and of static and dynamic parameters of bone formation and mineralization. Bone resorption increased independently of vitamin D status and did not correlate with plasma 1,25-dihydroxyvitamin D3 [1,25(OH)2D] levels, but it was associated with increased plasma immunoreactive parathyroid hormone (iPTH) concentrations. Stimulation of the endosteal bone formation rate was mainly impaired in D-depleted rats, resulting in trabecular bone loss, which, in -D mother rats, was associated with decreased bone ash and total bone calcium. Lactation further stimulated bone resorption and reduced the trabecular bone volume; ash weight and bone calcium content were also decreased independently of the vitamin D status and changes in plasma iPTH levels. In presence of vitamin D, the bone formation rate increased fourfold during lactation but was unchanged in -D lactating rats. During lactation, vitamin D-depleted rats lost twofold more calcified bone than +D rats because of impaired mineralization. Thus, the present study shows that both the endosteal bone resorption and formation are stimulated by pregnancy and lactation and that vitamin D is required for normal bone mineralization during the reproductive period.

Vitamin D Stimulation of [3H]Orotic Acid Incorporation into Ribonucleic Acid of Rat Intestinal Mucosa*

Biochemistry ◽  
1967 ◽  
Vol 6 (5) ◽  
pp. 1304-1310 ◽  
Author(s):  
Sidney J. Stohs ◽  
J. Elwood Zull ◽  
H. F. DeLuca
Keyword(s):  
Vitamin D ◽  
Intestinal Mucosa ◽  
Ribonucleic Acid ◽  
Orotic Acid ◽  
Acid Incorporation ◽  
Stimulation Of
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