scholarly journals THE NATURE AND PROCESSING OF RIBOSOMAL RIBONUCLEIC ACID IN A DINOFLAGELLATE

1970 ◽  
Vol 46 (1) ◽  
pp. 106-113 ◽  
Author(s):  
Peter M. M. Rae
Keyword(s):  
Ribosomal Rna ◽  
Ribonucleic Acid ◽  
Higher Plants ◽  
Primitive Form ◽  
Radioactive Precursor ◽  
Eukaryotic Nucleus ◽  
Ribosomal Ribonucleic Acid ◽  
Nucleotide Ratio ◽  
Kinetics Of

Certain features of the dinoflagellate nucleus suggest that it represents a primitive form of eukaryotic nucleus. For this reason, it was of interest to characterize dinoflagellate ribosomal RNA (rRNA) and its mode of synthesis to determine if it also deviated from typical eukaryotic patterns. Gyrodinium cohnii was chosen for this examination. Gyrodinium ribosomal RNA species are 16 and 25s as judged by their sedimentation velocities in isokinetic sucrose gradients. These values are typical of higher plants. In addition, the RNA cosedimented precisely with rRNA from the ciliate Tetrahymena. Nucleotide ratio analyses revealed a GMP + CMP content of 46% for both species of rRNA. The kinetics of incorporation of a radioactive precursor into ribosomal RNA have also been studied, and it seems likely that the maturation of rRNA starts with the synthesis of a 38s molecule. This serves as precursor to the 16s species, and, after a 27s intermediate, the 25s ribosomal component. The process is similar to that in other eukaryotes. The structure of the nucleolus has also been examined, and is seen to be typically eukaryotic.

scholarly journals Identical 3′-terminal octanucleotide sequence in 18S ribosomal ribonucleic acid from different eukaryotes. A proposed role for this sequence in the recognition of terminator codons

1974 ◽  
Vol 141 (3) ◽  
pp. 609-615 ◽  
Author(s):  
John Shine ◽  
Lynn Dalgarno
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Synthesis ◽  
Drosophila Melanogaster ◽  
Ribosomal Rna ◽  
Ribonucleic Acid ◽  
18S Rrna ◽  
Base Sequence ◽  
Terminal Sequence ◽  
Ribosomal Ribonucleic Acid ◽  
Rrna Species

The 3′-terminal sequence of 18S ribosomal RNA from Drosophila melanogaster and Saccharomyces cerevisiae was determined by stepwise degradation from the 3′-terminus and labelling with [3H]isoniazid. The sequence G-A-U-C-A-U-U-AOH was found at the 3′-terminus of both 18S rRNA species. Less extensive data for 18S RNA from a number of other eukaryotes are consistent with the same 3′-terminal sequence, and an identical sequence has previously been reported for the 3′-end of rabbit reticulocyte 18S rRNA (Hunt, 1970). These results suggest that the base sequence in this region is strongly conserved and may be identical in all eukaryotes. As the 3′-terminal hexanucleotide is complementary to eukaryotic terminator codons we discuss the possibility that the 3′-end of 18S rRNA may have a direct base-pairing role in the termination of protein synthesis.

scholarly journals The binding of spermine to the ribosomes and ribosomal ribonucleic acid from Bacillus stearothermophilus

1969 ◽  
Vol 113 (1) ◽  
pp. 117-121 ◽  
Author(s):  
L. Stevens
Keyword(s):  
Ionic Strength ◽  
Ribosomal Rna ◽  
Ribonucleic Acid ◽  
Binding Sites ◽  
Bacillus Stearothermophilus ◽  
Gel Filtration ◽  
Ribosomal Ribonucleic Acid ◽  
Number Of Binding Sites ◽  
Filtration Technique

1. The total intracellular concentrations of Na+, K+, Mg2+, spermine, spermidine and RNA were measured in Bacillus stearothermophilus. 2. The binding of spermine to ribosomes and to ribosomal RNA from B. stearothermophilus was studied under various conditions by using a gel-filtration technique. 3. The affinity of spermine for ribosomes and for ribosomal RNA decreased with increasing ionic strength of the medium in which they were suspended. 4. The extent of spermine binding did not change appreciably in the temperature range 4–60°. 5. Optimum binding occurred at about pH7·0. 6. The number of binding sites for spermine on either ribosomes or ribosomal RNA was 0·10–0·13/RNA phosphate group. 7. A high proportion of the intracellular spermine is likely to be bound to the ribosomes in vivo; spermine competes with Mg2+ on equal terms for sites on the ribosomes.

scholarly journals Dual pathways for ribonucleic acid turnover in WI-38 but not in I-cell human diploid fibroblasts.

1981 ◽  
Vol 1 (1) ◽  
pp. 75-81 ◽  
Author(s):  
M Sameshima ◽  
S A Liebhaber ◽  
D Schlessinger
Keyword(s):  
Ribosomal Rna ◽  
Ribonucleic Acid ◽  
Protein Turnover ◽  
Rna Turnover ◽  
Turnover Rates ◽  
Diploid Fibroblasts ◽  
Human Diploid Fibroblasts ◽  
Cytoplasmic Rna ◽  
Ribosomal Ribonucleic Acid ◽  
I Cells

The turnover rates of 3H-labeled 18S ribosomal ribonucleic acid (RNA), 28S ribosomal RNA, transfer RNA, and total cytoplasmic RNA were very similar in growing WI-38 diploid fibroblasts. The rate of turnover was at least twofold greater when cell growth stopped due to cell confluence, 3H irradiation, or treatment with 20 mM NaN3 or 2 mM NaF. In contrast, the rate of total 3H-protein turnover was the same in growing and nongrowing cells. Both RNA and protein turnovers were accelerated at least twofold in WI-38 cells deprived of serum, and this increase in turnover was inhibited by NH4Cl. These results are consistent with two pathways for RNA turnover, one of them being nonlysosomal and the other being lysosome mediated (NH4Cl sensitive), as has been suggested for protein turnover. Also consistent with the notion of two pathways for RNA turnover were findings with I-cells, which are deficient for many lysosomal enzymes, and in which all RNA turnover was nonlysosomal (NH4Cl resistant).

scholarly journals Deoxyribonucleic acid–ribonucleic acid hybridization. Annealing and quantitative recovery of intact ribosomal ribonucleic acid molecules from hybrids

1969 ◽  
Vol 115 (2) ◽  
pp. 287-294 ◽  
Author(s):  
Michael Fry ◽  
Michael Artman
Keyword(s):  
Ribosomal Rna ◽  
Ribonucleic Acid ◽  
Messenger Rna ◽  
Deoxyribonucleic Acid ◽  
Cellulose Nitrate ◽  
Absolute Size ◽  
Rna Molecules ◽  
Membrane Filters ◽  
Ribosomal Ribonucleic Acid

A simple and efficient method for hybridization and subsequent recovery of non-fragmented ribosomal RNA from the hybrid is described. The procedure involves annealing of immobilized denatured DNA bound on cellulose nitrate membrane filters to complementary RNA in 50% (v/v) formamide–0·33m-potassium chloride–10mm-tris–hydrochloric acid buffer, pH7·4, at 33° for 3hr. Under these conditions no detectable changes in the sedimentation coefficients of the input RNA were detected. The RNA can subsequently be recovered quantitatively from the hybrid in intact form by incubating the filters in formamide or in 85% (v/v) dimethyl sulphoxide. The applicability of the method for the evaluation of the absolute size of ribosomal RNA cistrons in Escherichia coli DNA and for the determination of the size of messenger RNA molecules is discussed.

scholarly journals The Genes for Cytoplasmic Ribosomal Ribonucleic Acid in Higher Plants

1973 ◽  
Vol 51 (4) ◽  
pp. 677-684 ◽  
Author(s):  
N. Steele Scott ◽  
J. Ingle
Keyword(s):  
Ribonucleic Acid ◽  
Higher Plants ◽  
Ribosomal Ribonucleic Acid

Dual pathways for ribonucleic acid turnover in WI-38 but not in I-cell human diploid fibroblasts

1981 ◽  
Vol 1 (1) ◽  
pp. 75-81
Author(s):  
M Sameshima ◽  
S A Liebhaber ◽  
D Schlessinger
Keyword(s):  
Ribosomal Rna ◽  
Ribonucleic Acid ◽  
Protein Turnover ◽  
Rna Turnover ◽  
Turnover Rates ◽  
Diploid Fibroblasts ◽  
Human Diploid Fibroblasts ◽  
Cytoplasmic Rna ◽  
Ribosomal Ribonucleic Acid ◽  
I Cells

The turnover rates of 3H-labeled 18S ribosomal ribonucleic acid (RNA), 28S ribosomal RNA, transfer RNA, and total cytoplasmic RNA were very similar in growing WI-38 diploid fibroblasts. The rate of turnover was at least twofold greater when cell growth stopped due to cell confluence, 3H irradiation, or treatment with 20 mM NaN3 or 2 mM NaF. In contrast, the rate of total 3H-protein turnover was the same in growing and nongrowing cells. Both RNA and protein turnovers were accelerated at least twofold in WI-38 cells deprived of serum, and this increase in turnover was inhibited by NH4Cl. These results are consistent with two pathways for RNA turnover, one of them being nonlysosomal and the other being lysosome mediated (NH4Cl sensitive), as has been suggested for protein turnover. Also consistent with the notion of two pathways for RNA turnover were findings with I-cells, which are deficient for many lysosomal enzymes, and in which all RNA turnover was nonlysosomal (NH4Cl resistant).

scholarly journals 16s and 23s components in the ribosomal ribonucleic acid of Rhodopseudomonas spheroides

1968 ◽  
Vol 109 (2) ◽  
pp. 191-195 ◽  
Author(s):  
J. F. Szilágyi
Keyword(s):  
Ribosomal Rna ◽  
Ultrasonic Treatment ◽  
Ribonucleic Acid ◽  
Gradient Centrifugation ◽  
Cell Lysate ◽  
Ribosomal Ribonucleic Acid ◽  
Rhodopseudomonas Spheroides ◽  
Ribonuclease Inhibitors ◽  
Method Of Extraction

1. Ribosomal RNA was extracted from lysates of Rhodopseudomonas spheroides without prior isolation of ribosomes. 2. The composition of this RNA was investigated by using gradient centrifugation, showing that the proportion present as 23s component depended on the method of extraction. 3. The highest proportion of 23s component was found when cells were disrupted by ultrasonic treatment in the presence of ribonuclease inhibitors. 4. The results indicated that a ribonuclease is active in the cell lysate; this could account for the previous report (Lessie, 1965) that ribosomes of Rhodopseudomonas spheroides do not contain a 23s component.

scholarly journals The preparation of ribosomal ribonucleic acid from whole bacteria

1968 ◽  
Vol 106 (4) ◽  
pp. 897-903 ◽  
Author(s):  
H. K. Robinson ◽  
H. E. Wade
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Pseudomonas Fluorescens ◽  
Ribosomal Rna ◽  
Staphylococcus Epidermidis ◽  
Ribonucleic Acid ◽  
Potassium Acetate ◽  
Sedimentation Pattern ◽  
Simple Method ◽  
Ribosomal Ribonucleic Acid

1. A simple method for the preparation of ribonuclease-free ribosomal RNA is described in which ribonuclease-deficient bacteria are treated with acetone and the RNA is extracted with phenol and purified by precipitating it with potassium acetate. The treatment with acetone appears to render the cell wall permeable to RNA but not to DNA during the extraction with phenol. The method thus avoids the need to disrupt the bacteria and greatly simplifies the subsequent purification. 2. The method has been used successfully with ribonuclease-deficient strains of Escherichia coli, Pseudomonas fluorescens and Staphylococcus epidermidis. The recovered purified RNA accounts for about 70% of the total ribosomal RNA and shows the normal sedimentation pattern of the 16s and 23s components in the analytical centrifuge.

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