The ribosomes of Plasmodium berghei: isolation and ribosomal ribonucleic acid analysis

Parasitology ◽  
1978 ◽  
Vol 77 (3) ◽  
pp. 345-366 ◽  
Author(s):  
F. W. Miller ◽  
Judith Ilan
Keyword(s):  
Plasmodium Berghei ◽  
Ribonucleic Acid ◽  
Ribosomal Subunit ◽  
High Yield ◽  
Small Component ◽  
40S Ribosomal Subunit ◽  
Ribosomal Ribonucleic Acid ◽  
Rrna Species ◽  
Specific Degradation ◽  
Triton X

SummaryRibosomes and high molecular weight ribosomal ribonucleic acid (rRNA) from the blood stages of Plasmodium berghei parasites were studied in preparations free from host ribosome contamination. Purified malarial ribosomes were isolated in high yield from a population of ultrastructurally intact, viable parasites by hypertonic lysis with Triton X-100 and differential centrifugation. These ribosomes were shown to be derived from active polysomes and could be dissociated into subunits by puromycin–0·5 m KCl treatment. Malarial rRNA extracted from purified 40S and 60S ribosomal subunits was characterized by electrophoretic, sedimentation and base ratio analyses. Like certain other protozoa, the P. berghei 40S ribosomal subunit possessed an exceptionally large RNA species (mol. wt 0·9 × 106), while RNA isolated from the parasite's 60S subunit (mol. wt 1·5 × 106) was specifically ‘nicked’ to produce one large component (mol.wt 1·2 × 106) and one small component (mol.wt 0·3 × 106) in equimolar quantities. These rRNA's migrate identically on polyacrylamide gels after heating to 63°C for 5 mm or under denaturing conditions in the presence of formamide, indicating an absence of aggregation and non-specific degradation of the rRNA species. Base composition studies showed P. berghei rRNA to be low in guanosine and cytosine content, as is the case for protozoa generally.

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 Higher-plant mitochondrial ribosomes contain a 5S ribosomal ribonucleic acid component

1976 ◽  
Vol 157 (1) ◽  
pp. 275-277 ◽  
Author(s):  
C J Leaver ◽  
M A Harmey
Keyword(s):  
Ribonucleic Acid ◽  
Plant Mitochondria ◽  
5S Rrna ◽  
Higher Plant ◽  
Acid Component ◽  
Mitochondrial Ribosomes ◽  
Ribosomal Ribonucleic Acid ◽  
Rrna Species ◽  
Hydrogen Bonded

Ribosomes from higher-plant mitochondria contain 5S rRNA, in contrast with the mitochondrial ribosomes of animals and fungi, in which such a component has not been detected. In common with the ribosomes of prokaryotes and chloroplasts, higher-plant mitochondrial ribosomes do not appear to contain an RNA equivalent to the 5.8 S rRNA that is found in eukaryoytes hydrogen-bonded to the largest of the cytoplasmic rRNA species.

scholarly journals The molecular integrity of chloroplast ribosomal ribonucleic acid

1971 ◽  
Vol 123 (2) ◽  
pp. 235-243 ◽  
Author(s):  
C. J. Leaver ◽  
J. Ingle
Keyword(s):  
Plant Species ◽  
Ribonucleic Acid ◽  
Ribosomal Ribonucleic Acid ◽  
Rrna Species ◽  
Chloroplast Rna ◽  
The Stability

Instability of chloroplast rRNA has been observed with essentially all chloroplast RNA preparations. This paper describes experiments that show that, under normal conditions of preparation and fractionation, only the heavy chloroplast component (mol.wt. 1.1×106) is unstable, the light chloroplast rRNA (mol.wt. 0.56×106) and the cytoplasmic rRNA species (mol.wt. 1.3×106 and 0.70×106) being stable. The stability of the 1.1×106-mol. wt. molecule varies with different plant species, as also does the size and the number of fragments produced. Cleavages in three particular regions of the molecule are very frequent within the range of tissues studied. The 1.1×106-mol.wt. rRNA is, however, stabilized by the presence of Mg2+ during the preparation and fractionation of the RNA.

scholarly journals Terminal-sequence studies of high-molecular-weight ribonucleic acid. The 3′-termini of rabbit reticulocyte ribosomal ribonucleic acid

1970 ◽  
Vol 120 (2) ◽  
pp. 353-363 ◽  
Author(s):  
John A. Hunt
Keyword(s):  
Ribonucleic Acid ◽  
Periodate Oxidation ◽  
Ribosomal Subunit ◽  
Large Ribosomal Subunit ◽  
Terminal Sequence ◽  
Ribosomal Subunits ◽  
Rna Molecules ◽  
Ribosomal Ribonucleic Acid ◽  
Rabbit Reticulocytes

Sequences of the polynucleotide chains of RNA found in the large and small ribosomal subunits of rabbit reticulocytes have been determined from the 3′-end by use of periodate oxidation and condensation with [3H]isoniazid and by stepwise degradation. By these methods the hexanucleotide sequences have been found as -pGpUpUpUpGpU for the 28S RNA and -pGpUpCpGpCpU for the 6S RNA of the large ribosomal subunit and the octanucleotide sequence -pGpApUpCpApUpUpA for the 18S rRNA of the small ribosomal subunit. These sequences are present in at least 70% of all the RNA molecules and are discussed in relation to the specific cleavage of rRNA from its precursors and the role of multiple cistrons for rRNA in the DNA of higher organisms. The feasibility of using the method for longer sequence determinations is discussed.

Three-dimensional reconstruction of the 40S ribosomal subunit from rabbit reticulocytes

1987 ◽  
Vol 45 ◽  
pp. 936-937
Author(s):  
Neng-Yu Zhang ◽  
Terence Wagenknecht ◽  
Michael Radermacher ◽  
Tom Obrig ◽  
Joachim Frank
Keyword(s):  
Three Dimensional ◽  
Ribosomal Subunit ◽  
Uranyl Acetate ◽  
Reconstruction Method ◽  
Single Exposure ◽  
Electron Dose ◽  
Ribosomal Subunits ◽  
40S Ribosomal Subunit ◽  
Dimensional Reconstruction ◽  
Rabbit Reticulocytes

We have reconstructed the 40S ribosomal subunit at a resolution of 4 nm using the single-exposure pseudo-conical reconstruction method of Radermacher et al.Small (40S) ribosomal subunits were Isolated from rabbit reticulocytes, applied to grids and negatively stained (0.5% uranyl acetate) in a manner that “sandwiches” the specimen between two layers of carbon. Regions of the grid exhibiting uniform and thick staining were identified and photographed twice (magnification 49,000X). The first micrograph was always taken with the specimen tilted by 50° and the second was of the Identical area untilted (Fig. 1). For each of the micrographs the specimen was subjected to an electron dose of 2000-3000 el/nm2.Three hundred thirty particles appearing in the L view (defined in [4]) were selected from both tilted- and untilted-specimen micrographs. The untilted particles were aligned and their rotational alignment produced the azimuthal angles of the tilted particles in the conical tilt series.

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