Nucleic acid synthesis in microsporocytes of Lilium cv. cinnabar: events in the nucleus

1982 ◽  
Vol 57 (1) ◽  
pp. 229-246
Author(s):  
E.K. Porter ◽  
J.M. Bird ◽  
H.G. Dickinson
Keyword(s):  
Nucleic Acid ◽  
Chromosome Pairing ◽  
Rna Synthesis ◽  
Dna Amplification ◽  
Acid Synthesis ◽  
Autoradiographic Study ◽  
Crossing Over ◽  
Electron Microscopic ◽  
Dna And Rna ◽  
Dna And Rna Synthesis

In an electron microscopic autoradiographic study of DNA and RNA synthesis during meiosis isolated Lilium microsporocytes were supplied with [3H]thymidine and [3H]uridine. DNA synthesis occurred in the nucleus during the zygotene and pachytene intervals of meiotic prophase. Most of the activity was associated with the chromatin, but some synthesis early in zygotene was located at the nucleolus. RNA synthesis occurred throughout prophase until diplotene, when all activity ceased until after division. The newly synthesized RNA was found mostly in association with the chromosomal peripheries or in the space between chromosomes. There was also a peak of [3H]uridine incorporation at the nucleolus, which followed shortly after the synthesis of DNA at that site. The localization of DNA and RNA synthesis at the various stages of meiosis is discussed in relation to current concepts of chromosome pairing, crossing-over, ribosomal DNA amplification and cycles of RNA metabolism.

Inhibition of nucleic acid synthesis in L1210 cells by nucleoside analogs

1984 ◽  
Vol 49 (11) ◽  
pp. 2551-2556 ◽  
Author(s):  
Jiří Beránek ◽  
Edward M. Acton
Keyword(s):  
Nucleic Acid ◽  
Rna Synthesis ◽  
Nucleoside Analogs ◽  
Acid Synthesis ◽  
Pyrimidine Nucleoside ◽  
Dna And Rna ◽  
L1210 Cells ◽  
Structure Activity ◽  
Dna And Rna Synthesis ◽  
Chloro Derivatives

Series of pyrimidine nucleoside analogs were tested for inhibition of DNA and/or RNA synthesis at L1210 cells. The structure-activity relationship was studied at the analogs of cancerostatic agents 5-fluorouracil and arabinosylcytosine. Out of them the 5'-chloro derivatives give some promise. The inhibitory activity of cyclocytidine vs DNA and RNA synthesis approaches the activity of cancerostatic antibotics.

scholarly journals SYNTHETIC CAPACITIES OF CHROMOSOME FRAGMENTS CORRELATED WITH THEIR ABILITY TO MAINTAIN NUCLEOLAR MATERIAL

1962 ◽  
Vol 15 (1) ◽  
pp. 121-130 ◽  
Author(s):  
Nirmal K. Das
Keyword(s):  
Nucleic Acid ◽  
Rna Synthesis ◽  
Acid Synthesis ◽  
Root Tip ◽  
Dna And Rna ◽  
Nucleolar Material ◽  
Dna And Rna Synthesis ◽  
Chromosome Fragments ◽  
Cellular Control ◽  
Mitotic Chromosome Condensation

Onion (Allium cepa) and bean (Vicia faba) root tip cells containing many micronuclei, derived from x-ray-induced chromosome fragments, were exposed to H3-thymidine and H3-cytidine to determine the ability of such fragments to undergo DNA and RNA synthesis. Only a few micronuclei in onion and many in bean roots synthesize nucleic acid simultaneously with their main nuclei. A few micronuclei labeled with H3-thymidine undergo mitotic chromosome condensation along with the main nuclei, while the unlabeled ones never do so. The onset of nucleic acid synthesis as well as mitosis in micronuclei appears to be under generalized cellular control. Although all chromosomes and chromosome fragments at telophase give a positive reaction for a silver stainable nucleolar fraction, in the subsequent interphase only some micronuclei, derived from such chromosome fragments, are found to maintain nucleoli; others lose them with time. Those micronuclei which maintain nucleoli, perhaps due to the presence of specific chromosomal regions, are also active in DNA and RNA synthesis. These results are compatible with the concept that nucleoli and associated chromosome regions play an important role in the primary biosynthetic processes of the cell.

scholarly journals Mechanism of action of purpuromycin

1992 ◽  
Vol 284 (1) ◽  
pp. 47-52 ◽  
Author(s):  
P Landini ◽  
E Corti ◽  
B P Goldstein ◽  
M Denaro
Keyword(s):  
Protein Synthesis ◽  
Rna Synthesis ◽  
Intact Cell ◽  
Acid Synthesis ◽  
Free System ◽  
Dna And Rna ◽  
Dna And Rna Synthesis ◽  
Dependent Protein ◽  
Elongation Step

Purpuromycin, an antibiotic active against both fungi and bacteria, shows different modes of action against these two kinds of micro-organisms; in Candida albicans it inhibits RNA synthesis, whereas in Bacillus subtilis protein synthesis is primarily affected, with DNA and RNA synthesis blocked at higher concentrations of the drug. In bacterial cell-free protein-synthesis systems, purpuromycin did not inhibit synthesis from endogenous mRNA (elongation of peptides initiated within the intact cell) but inhibited MS2-phase RNA-dependent protein synthesis (which requires initiation) by 50% at 0.1 mg/l. Poly(U)-directed polyphenylalanine synthesis was 50% inhibited by 20 mg of purpuromycin/l when added to a complete system; however, when purpuromycin was preincubated with ribosomes dissociated into 30 S and 50 S subunits, the concentration for 50% inhibition fell to 0.1 mg/l. By contrast, in a C. albicans cell-free system poly(U)-directed polyphenylalanine synthesis was partially inhibited only at 200 mg/l. Purpuromycin also inhibited polynucleotide synthesis in vitro in reactions using Escherichia coli or wheat-germ RNA polymerases or E. coli DNA polymerase I. We suggest that in bacteria the primary target of purpuromycin is on ribosomes and that its action precedes the elongation step of protein synthesis. The effect on nucleic acid synthesis in both fungi and bacteria may be due to interaction of purpuromycin with DNA.

scholarly journals Lomofungin as an inhibitor of nucleic acid synthesis in Saccharomyces cerevisiae

1974 ◽  
Vol 142 (3) ◽  
pp. 457-463 ◽  
Author(s):  
Michael Cannon ◽  
Antonio Jimenez
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Synthesis ◽  
Rna Synthesis ◽  
Acid Synthesis ◽  
Growth Conditions ◽  
Dna And Rna ◽  
Dna And Rna Synthesis ◽  
Inhibition Of Dna Synthesis ◽  
Rna And Dna Synthesis ◽  
Rna And Dna

1. The antibiotic lomofungin was found to be a potent inhibitor of both DNA and RNA synthesis in Saccharomyces cerevisiae. Under selected growth conditions inhibition of DNA synthesis by the drug preceded inhibition of RNA synthesis. 2. Although in general lomofungin inhibited synthesis of ribosomal RNA and polydisperse RNA more effectively than that of low-molecular-weight RNA, under certain conditions the drug inhibited almost completely synthesis of both 4S and 5S RNA. 3. Inhibition of both RNA and DNA synthesis may be explained if RNA synthesis is required for DNA synthesis in yeast. Alternatively, lomofungin, in addition to interacting with DNA-dependent RNA polymerase, might interfere with a component(s) of the DNA-synthetic apparatus. The drug may thus prove to be of considerable value in studies of DNA synthesis in eukaryotes.

Infectious Mononucleosis An Autoradiographic Study of DNA-and RNA-Synthesis

2009 ◽  
Vol 2 (1) ◽  
pp. 18-30 ◽  
Author(s):  
Jakob R. Schmid ◽  
Robert J. Oechslin ◽  
Sven Moeschlin
Keyword(s):  
Infectious Mononucleosis ◽  
Rna Synthesis ◽  
Autoradiographic Study ◽  
Dna And Rna ◽  
Dna And Rna Synthesis

The role of p53 in regulating genomic stability when DNA and RNA synthesis are inhibited

1995 ◽  
Vol 20 (10) ◽  
pp. 431-434 ◽  
Author(s):  
Olga B. Chernova ◽  
Michail V. Chernov ◽  
Munna L. Agarwal ◽  
William R. Taylor ◽  
George R. Stark
Keyword(s):  
Rna Synthesis ◽  
Genomic Stability ◽  
Dna And Rna ◽  
Dna And Rna Synthesis

Effect of Cytokinins on the Expansion and Metabolism of Excised Cucumber Cotyledons

1980 ◽  
Vol 7 (3) ◽  
pp. 227
Author(s):  
C Tsui ◽  
Tao Guo-qing ◽  
Chen Hui-ying ◽  
Son Yan-ru ◽  
Lian Han-ping ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Soluble Sugars ◽  
Dry Weight ◽  
Acid Synthesis ◽  
Cell Number ◽  
Cucumis Sativus L ◽  
Biochemical Processes ◽  
Dna And Rna ◽  
Lag Period ◽  
Hydrolysis Of

Expansion of excised cucumber (Cucumis sativus L.) cotyledons was stimulated by treatment with cytokinin, and commenced after a lag period of about 4 h. Expansion induced by benzyladenine (BA) was due mainly to increase of fresh weight, but cell number increased slightly. Hydrolysis of protein and lipid was stimulated by BA, and soluble sugars increased simultaneously. However, there was no significant change in the dry weight of cotyledons during the period of expansion. It is assumed that the transformation of lipid to sugar in the cotyledon is stimulated by BA. The respiration of cotyledons was evidently stimulated by BA and was entirely inhibited by respiratory inhibitors, e.g. NaN,, malonate and dinitrophenol. Inhibitors of protein and nucleic acid synthesis, such as chloramphenicol and actinomycin D, inhibited only the BA-induced expansion. They had no effect on the expansion of controls. These results suggest that different biochemical processes are involved in the expansion of cotyledons induced by BA and in controls. The former is related not only to respiration but also to the synthesis of protein and nucleic acid. BA increased DNA and RNA content per cotyledon. The increase of total RNA is due mainly to the increase of 25 S and 18 S rRNA.

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