scholarly journals Alterations in Nuclear Ribonucleic Acid Metabolism Induced by Kinetin

1957 ◽  
Vol 3 (1) ◽  
pp. 129-132 ◽  
Author(s):  
Ruth Guttman
Keyword(s):  
Cell Division ◽  
Ribonucleic Acid ◽  
Deoxyribonucleic Acid ◽  
Acid Metabolism ◽  
Root Cells ◽  
Onion Root ◽  
Azure B ◽  
Division Factor

Removal of deoxyribonucleic acid from meristematic onion root cells grown in solutions of kinetin, followed by metachromatic staining in azure B bromide, indicated the presence of appreciable amounts of ribonucleic acid in nuclei exposed to the cell division factor.

Nuclei in haustoria of Phytophthora infestans

1969 ◽  
Vol 47 (10) ◽  
pp. 1585-1587 ◽  
Author(s):  
Bela Sivak ◽  
Michael Shaw
Keyword(s):  
Phytophthora Infestans ◽  
Ribonucleic Acid ◽  
Deoxyribonucleic Acid ◽  
Azure B

Haustoria of Phytophthora infestans (Mont.) DeBary were stained for ribonucleic acid (RNA) using azure B dye at pH 4.0 after the enzymatic removal of deoxyribonucleic acid (DNA). Nuclei were shown to be present in haustoria from 12 to 35 h after inoculation.

EFFECT OF OESTRADIOL-17β ON CLEAVAGE, NUCLEIC ACID METABOLISM AND PROTEIN SYNTHESIS IN SEA URCHIN, STRONGYLOCENTROTUS PURPURATUS, EMBRYOS

1962 ◽  
Vol 25 (2) ◽  
pp. 183-NP ◽  
Author(s):  
W. B. JOLLEY ◽  
W. E. MARTIN ◽  
J. W. BAMBERGER ◽  
L. W. STEARNS
Keyword(s):  
Protein Synthesis ◽  
Nucleic Acid ◽  
Sea Urchin ◽  
Ribonucleic Acid ◽  
Deoxyribonucleic Acid ◽  
Acid Metabolism ◽  
Strongylocentrotus Purpuratus ◽  
Nucleic Acid Metabolism ◽  
Dna And Rna ◽  
Moderate Effect

SUMMARY Oestradiol-17β at a concentration of 3 × 10−3 m inhibits cleavage in sea urchin (Strongylocentrotus purpuratus) embryos. This inhibition is accompanied by a reduction in deoxyribonucleic acid (DNA) synthesis and little change in ribonucleic acid (RNA). The effects of oestradiol-17β upon the incorporation of glycine-1-14C and glycine-2-14C into the purines of DNA and RNA and the incorporation of glycine-2-14C into serine were studied. The incorporation of glycine-1-14C and glycine-2-14C into RNA was reduced, but the incorporation of glycine-2-14C into DNA was increased considerably over that of the controls. The incorporation of glycine-2-14C into serine was also accelerated by oestradiol. A possible explanation of the action of oestradiol-17β is offered. The moderate effect upon RNA is not surprising because there is little or no synthesis of this compound from the time of fertilization to blastulation under normal conditions.

Continuous light or darkness and circadian periodic mitosis and metabolism in C and D8 mice

1961 ◽  
Vol 201 (2) ◽  
pp. 227-230 ◽  
Author(s):  
Franz Halberg ◽  
Cyrus P. Barnum
Keyword(s):  
Cell Division ◽  
Circadian Rhythms ◽  
Deoxyribonucleic Acid ◽  
Acid Metabolism ◽  
Specific Activity ◽  
Continuous Light ◽  
Liver Parenchyma ◽  
Constant Light ◽  
Constant Darkness ◽  
Spot Check

In immature C mice exposed first to alternating 12 hr of light and 12 hr of darkness (LD), and maintained thereafter in constant darkness for several days, the circadian rhythms in hepatic and pinnal mitosis are demonstrable by spot checks made at the approximate times of LD-synchronized peak and trough. Spot checks at same times in mice of same stock and age, kept for several days in constant light, reveal the cell division rhythm of liver parenchyma, but not that of pinnal epidermis. In immature D8 mice kept for several days in constant darkness, rhythms in hepatic mitosis, phospholipid, ribonucleic and deoxyribonucleic acid metabolism persist, while cell division rhythm in ear pinna of same animals is not detectable with the particular spot check used. In mice of same stock and age, on the 4th day in constant light, a significant rhythm persists in the relative specific activity of the hepatic phospholipid; timing of this metabolic cellular rhythm is drastically desynchronized from the reference standard of a 24-hr clock. Data reveal persistence of some mitotic and metabolic circadian rhythms under conditions studied, with phase drifts or phase shifts of these rhythms occurring both in relation to the 24-hr clock and among the rhythms themselves. These changes in external and internal timing of a circadian system are more extensive in constant light than in constant darkness.

scholarly journals Artemisinin-Based Combination Therapy Depressed Mitosis and Induced Chromosome Aberration in Onion Root Cells

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
J. I. Raji ◽  
C. K. Onwuamah ◽  
P. G. C. Odeigah
Keyword(s):  
Cell Division ◽  
Combination Therapy ◽  
Chromosome Aberrations ◽  
Uncomplicated Malaria ◽  
Artemisinin Combination Therapy ◽  
Genetic Damage ◽  
Root Cells ◽  
Onion Root ◽  
Chromosome Fragments ◽  
Chromosome Bridges

Artemisinin-based combination therapy is used to treat uncomplicated malaria disease in most endemic countries. Although most antimalarial drugs are effective in killing the parasite, there is a concern of induced toxicity to the cell. Here, the cytogenotoxicity of dihydroartemisinin-piperaquine phosphate (DHAP), a coformulation for artemisinin-based combination therapy, was evaluated usingAllium cepamodel. The toxicity on the mitotic index varies with the duration of exposure and dose tested. Chromosome aberrations observed include chromosome fragments, chromosome bridges, binucleated cells, and micronucleated cells. This study showed that DHAP can depress mitosis and induce chromosome abnormalities. Their accumulation in cells may be inhibitory to cell division and growth. This calls for caution in the administration of artemisinin combination therapy for the treatment of malaria ailment. Wide spacing of dosage is therefore suggested in order to avoid the risk of genetic damage.

The effect of gibberellic acid on Hansenula wingei

1969 ◽  
Vol 15 (10) ◽  
pp. 1225-1230 ◽  
Author(s):  
Emile H. Makarem ◽  
Norman Alldridge
Keyword(s):  
Protein Synthesis ◽  
Cell Division ◽  
Gibberellic Acid ◽  
Ribonucleic Acid ◽  
Deoxyribonucleic Acid ◽  
Rna And Protein Synthesis ◽  
Hansenula Wingei

The present study shows the influence of gibberellic acid on the budding and cell division of three strains of Hansenula wingei. Gibberellic acid at 10 μg/ml increased cell division of all the strains of H. wingei tested. The rate of budding and cell division diminished as the concentration of gibberellic acid increased over or decreased below 10 μg/ml. Also tested was the ability of gibberellic acid at a concentration of 10 μg/ml to stimulate the synthesis of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein contents of both haploid and diploid strains of H. wingei. The rate of DNA, RNA, and protein synthesis decreased as the concentration of gibberellic acid was increased over or decreased below 10 μg/ml.

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