Protein Synthesis DNA Synthesis and Repair RNA Synthesis Energy-Linked ATPases Synthetases

1974 ◽  
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Rna Synthesis

A comparison of the synthesis of DNA, RNA and proteins in the embryos of after-ripened and thermo- or FR-dormant Agrostemma githago L. seeds

1995 ◽  
Vol 5 (2) ◽  
pp. 87-97 ◽  
Author(s):  
U. Gerth ◽  
D. Bernhardt
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Rna Synthesis ◽  
Gradual Decrease ◽  
Two Dimensional ◽  
Dark Incubation ◽  
Low Level ◽  
Developmental Arrest ◽  
Stimulation Of

AbstractImbibed embryos of after-ripened and secondarily thermo- and FR-dormant Agrostemma githago seeds were investigated as to their ability to synthesize DNA, RNA and proteins with the aim of finding characteristic differences connected with the induction and maintenance of developmental arrest. A gradual decrease in DNA synthesis was observed during the induction of thermodormancy. However, DNA synthesis was stimulated up to that of embryos of 30–h-imbibed after-ripened seeds within 24 h approximately after transferring the thermodormant seeds into temperatures which normally allow germination. DNA synthesis of embryos of FR-dormant seeds remained constant at a relatively low level during 7 d FR and another 7 d dark incubation. RNA synthesis decreased to different extents during induction of thermo- and FR-dormancy when it was arrested at a relatively low level in seeds transferred to temperatures which normally allow germination. Processes leading to an increase in RNA synthesis such as in embryos of after-ripened seeds appeared to be quantitatively and/or qualitatively repressed. Interestingly, protein synthesis was extremely depressed during induction of thermodormancy whereas it was slightly stimulated during induction of FR-dormancy. Nevertheless two-dimensional protein PAGE revealed several polypeptides which were new, increased, decreased or not synthesized predominantly in axes of thermo- and FR-dormant seeds in comparison to germinating after-ripened seeds. It is suggested that a connection exists between these polypeptides and the repression of germination. After transferring seconarily dormant seeds to temperatures which normally allow germination, a temporary stimulation of protein synthesis could be observed in both cases.

scholarly journals MACROMOLECULAR SYNTHESES RELATED TO THE REPRODUCTIVE CYST OF TETRAHYMENA PATULA

1973 ◽  
Vol 59 (3) ◽  
pp. 615-623 ◽  
Author(s):  
P. R. Gabe ◽  
L. E. de Bault
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Generation Time ◽  
Rna Synthesis ◽  
Culture Medium ◽  
Tritiated Thymidine ◽  
Growth Cycle ◽  
The Third ◽  
Rna And Protein Synthesis ◽  
The Mean

Macromolecular syntheses in encysted Tetrahymena patula were studied using Feulgen fluorescence cytophotometry, autoradiography, and inhibitors of RNA and protein synthesis. Cycloheximide significantly depressed protein synthesis and D-actinomycin effectively blocked RNA synthesis. Under these conditions, the cells within the cyst were unable to divide. Both cytophotometric measurements and autoradiographic data with tritiated thymidine show that DNA synthesis does not occur during the encystment divisions. Excysted cells placed in nutrient broth medium showed a prolonged generation time after the first cell growth cycle, and by the third generation the mean DNA content per cell was almost triple that of starved excysted cells. These findings indicate that (a) the encystment divisions require RNA and protein synthesis, which are apparently effected through turnover, (b) the encystment division cycles occur in the absence of DNA synthesis, and (c) excysted cells placed in culture medium may go through more than one DNA replication per cell cycle.

Insulin stimulates macromolecular synthesis in cultured glial cells from rat brain

1985 ◽  
Vol 249 (5) ◽  
pp. C484-C489 ◽  
Author(s):  
D. W. Clarke ◽  
F. T. Boyd ◽  
M. S. Kappy ◽  
M. K. Raizada
Keyword(s):  
Protein Synthesis ◽  
Growth Factor ◽  
Dna Synthesis ◽  
Rat Brain ◽  
Glial Cells ◽  
Rna Synthesis ◽  
Macromolecular Synthesis ◽  
Total Response ◽  
Dose Dependent ◽  
Stimulation Of

The effect of insulin on macromolecular synthesis in glial cells cultured from brains of 1-day-old rats was studied to investigate the role of insulin in brain growth. Insulin caused a dose-dependent stimulation of protein synthesis (measured by [3H]valine incorporation into protein) that became significant by 7 nM insulin. Maximal stimulation of protein synthesis of 145% of control occurred with 18 nM insulin. Long-term protein synthesis was also stimulated to 136% of control by insulin in a dose-dependent manner after 6 days of insulin incubation. Insulin also stimulated net RNA and DNA synthesis (measured by [3H]uridine and [3H]thymidine incorporation into RNA or DNA, respectively) with significant stimulation by 2 nM insulin. Net RNA synthesis stimulation was maximal at 120% of control by 18 nM insulin. Plateau stimulation of DNA synthesis of 175% of control was reached by 200 nM insulin. The effects of insulin on glial protein and RNA synthesis appear to be mediated completely by the insulin receptor. Insulin, in physiological concentrations, stimulated glial DNA synthesis via its interaction with the insulin receptor (46% of total response). At supraphysiological concentrations insulin may have stimulated DNA synthesis via its cross-reactivity with the insulinlike growth factor I receptor (54% of total response). Thus insulin, at concentrations known to exist in the brain, stimulates the processes necessary for growth in the glial cell and is an important growth factor in the developing rat brain.

scholarly journals STUDIES ON THE MECHANISM OF ACTION OF PEDERINE

1968 ◽  
Vol 36 (3) ◽  
pp. 485-496 ◽  
Author(s):  
Agnese Brega ◽  
Arturo Falaschi ◽  
Luigi De Carli ◽  
Mario Pavan
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Cytotoxic Effect ◽  
Rna Synthesis ◽  
Cultured Cells ◽  
Specific Inhibitor ◽  
Cytological Examination ◽  
Effect Analysis ◽  
Inhibitor Of Protein Synthesis

Pederine, a drug extracted from the coleopter Paederus fuscipes, inhibits the growth of in vitro cultured cell lines at concentrations of the order of 1.5 nanogram/ml. Cytological examination shows a generalized cytotoxic effect. Analysis of macromolecular syntheses by the use of radioactive precursors shows that pederine causes an almost immediate block of protein and DNA synthesis, without affecting RNA synthesis. The effects on the synthesis of the two types of macromolecules remain nearly simultaneous even at the lowest active concentrations of pederine. Studies with cell-free systems show that the drug inhibits protein synthesis, whereas it is ineffective on the DNA-polymerizing activity. It seems, therefore, that the drug acts primarily on the amino acid-polymerizing system, and that the effect on DNA is secondary. This idea is strengthened by the observation that puromycin, a specific inhibitor of protein synthesis, also affects promptly DNA synthesis of in vitro cultured cells. Other authors have shown the same phenomenon with a number of inhibitors of protein synthesis; the properties of pederine support, therefore, the view that continuous protein synthesis is necessary for the maintenance of DNA replication in higher organisms.

EFFECT OF X-IRRADIATION ON DNA SYNTHESIS IN EHRLICH ASCITES CARCINOMA CELLS

1965 ◽  
Vol 43 (7) ◽  
pp. 859-864 ◽  
Author(s):  
Shan-Ching Sung
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Rna Synthesis ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Total Rna ◽  
Ehrlich Ascites ◽  
Ehrlich Ascites Cells ◽  
X Irradiation

The rate of DNA synthesis in Ehrlich ascites cells measured immediately after X-irradiation of 500 r for 6 minutes in vitro showed about 15% reduction. However, if X-irradiation was followed by preincubation of the cells, the subsequent synthesis of DNA in the X-irradiated cells was markedly inhibited. Under the same condition, the uptake of thymidine-2-C14, uridine-2-C14, adenine-8-C14, and glycine-1-C14, and protein synthesis in the X-irradiated cells were found to be almost the same as those in the non-irradiated control. RNA synthesis measured as total RNA was only slightly inhibited.

scholarly journals SYNTHETIC ACTIVITIES DURING SPERMATOGENESIS IN THE LOCUST

1965 ◽  
Vol 25 (2) ◽  
pp. 387-395 ◽  
Author(s):  
Nirmal K. Das ◽  
Elsie P. Siegel ◽  
Max Alfert
Keyword(s):  
Protein Synthesis ◽  
Nucleic Acid ◽  
Dna Synthesis ◽  
X Chromosome ◽  
Rna Synthesis ◽  
Schistocerca Gregaria ◽  
Tritiated Thymidine ◽  
Chromatin Condensation ◽  
Chromosome Condensation ◽  
Meiotic Cycle

Isolated testes of the locust Schistocerca gregaria were immersed in solutions of tritiated thymidine, cytidine, uridine, or arginine for short periods to study nucleic acid and protein synthesis during spermatogenesis. DNA synthesis in this tissue is completed prior to initiation of meiosis. Protein synthesis continues throughout the whole meiotic cycle as well as during spermatid development. Meiotic cells, except those in metaphase through early telophase, and early spermatids are also actively synthesizing RNA. The heteropycnotic X-chromosome does not produce RNA at any stage of spermatogenesis. The rates of protein and particularly RNA synthesis decrease as chromosome condensation progresses. Depression of RNA synthesis, however, is not always accompanied by cytologically detectable condensation of chromatin, since very little or no RNA is synthesized in spermatids in which chromatin condensation has barely begun.

FEMALE ENDOCRINE CONTROL MECHANISMS DURING THE NEONATAL PERIOD

1972 ◽  
Vol 70 (2) ◽  
pp. 396-408 ◽  
Author(s):  
K.-D. Schulz ◽  
H. Haarmann ◽  
A. Harland
Keyword(s):  
Protein Synthesis ◽  
Reproductive System ◽  
Rna Synthesis ◽  
Neonatal Period ◽  
High Dose ◽  
Female Reproductive System ◽  
Endocrine Control ◽  
Hypothalamic Region ◽  
Rna And Protein Synthesis ◽  
Physiological Dose

ABSTRACT The present investigation deals with the oestrogen-sensitivity of the female reproductive system during the neonatal period. Newborn female guinea pigs were used as test animals. At different times after a single subcutaneous injection of a physiological dose of 0.1 μg or an unphysiologically high dose of 10 μg 17β-oestradiol/100 g body weight, the RNA- and protein-synthesis was examined in the hypothalamic region, pituitary, cerebral cortex, liver, adrenal gland, ovary and uterus. With a physiological dose an increase in organ weight, protein content, RNA-and protein-synthesis was found only in the uterus. These alterations turned out to be dose-dependent. In addition to the findings in the uterus an inhibition of the aminoacid incorporation rate occurred in the liver following the injection of the high oestradiol dose. As early as 1 hour after the administration of 0.1 μg 17β-oestradiol an almost 100% increase in uterine protein synthesis was detectable. This result demonstrates a high oestrogen-sensitivity of this organ during the neonatal period. All the other organs of the female reproductive system such as the hypothalamus, pituitary and ovary did not show any oestrogen response. Therefore the functional immaturity of the uterus during post partem life is not the result of a deficient hormone sensitivity but is correlated with the absence of a sufficient hormonal stimulus at this time. The investigation on the effects of actinomycin resulted in different reactions in the uterus and liver. In contrast to the liver a paradoxical actinomycin effect was found in the uterus after treatment with actinomycin alone. This effect is characterized by a small inhibition of RNA-synthesis and a 50% increase in protein synthesis. The treatment of the newborn test animals with actinomycin and 17β-oestradiol together abolished the oestrogen-induced stimulation of the uterine RNA-and protein-synthesis. Consequently, the effect of oestrogens during the neonatal period is also connected with the formation of new proteins via an increased DNA-directed RNA-synthesis.

Sign in / Sign up

Export Citation Format

Share Document