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At least 1,261 records · Page 70Linked to original sources
PubMed1995

Partial complementary deoxyribonucleic acid cloning of equine relaxin messenger ribonucleic acid, and its localization within the equine placenta.

To determine the site of relaxin gene expression in equine placentae, a set of degenerate oligonucleotide primers was made according to the published amino acid sequence of the A- and B-chain of equine relaxin (eRXN). Total cellular RNA (tcRNA) from equine placentae at about 120 and 300 days of pregnancy was subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) with use of these primers. A single amplification product of approximately 430 bp was detected in each case by agarose gel electrophoresis. The PCR product was ligated into Bluescript plasmid and sequenced to confirm the identity of the clone as an eRXN cDNA fragment. Nucleic acid sequence analysis revealed a 428-bp eRXN cDNA fragment encoding for parts of the A- and B-chain and the connecting peptide (109 residues). Northern analysis of tcRNA from placentae of 120 and 300 days of pregnancy was carried out with use of antisense digoxigenin-labeled cRNA generated from the cDNA clone, and a single transcript of approximately 1 kb was detected. In situ hybridization on placental tissue at 120 and uteroplacental tissue at 300 days of pregnancy indicated that only the fetal trophoblastic cells expressed eRXN mRNA transcripts. The identity of these cells was confirmed by their positive staining with an antibody specific for equine trophoblast (cell surface) protein. Relaxin peptide was also detected immunohistochemically in samples of the same placental tissues. This is the first report of the nucleic acid sequence of eRXN. The study identified fetal trophoblast cells as the site of eRXN mRNA expression and protein secretion in the equine placenta.

Amino Acid Sequence↗
PubMed1975

Incorporation of mevalonic Acid into ribosylzeatin in tobacco callus ribonucleic Acid preparations.

The incorporation of (14)C-2-mevalonic acid into transfer RNA and ribosomal RNA (high molecular weight RNA) in rapidly growing, cytokinin-dependent tobacco (Nicotiana tabacum var. Wisconsin No. 38) callus cultures has been investigated. Approximately 40% of the label incorporated into transfer RNA was present in a ribonucleoside with chromatographic properties identical to those of cis-ribosylzeatin. The remainder of the label in the transfer RNA appears to be nonspecific incorporation resulting from degradation and metabolism of (14)C-2-mevalonic acid by the tobacco callus tissue. Although the total radioactivity incorporated into ribosomal RNA was roughly the same as in transfer RNA, the specific radioactivity of the transfer RNA was about four times higher than that of the ribosomal RNA, and the ribosomal RNA labeling could be distinguished from the cytokinin labeling observed in transfer RNA. The distributions of the (14)C-2-mevalonic acid label and cytokinin activity in tobacco callus transfer RNA fractionated by benzoylated diethylaminoethylcellulose chromatography indicate that at least two cytokinin-containing transfer RNA species are present in this tissue.

Journal Article↗
PubMed1981

Nogalamycin inhibits ribonucleic acid synthesis in growing and developing cells of the slime mold Dictyostelium discoideum.

Nogalamycin, an anthracycline antibiotic that intercalates into deoxyribonucleic acid, is a potent inhibitor of ribonucleic acid (RNA) synthesis in the slime mold Dictyostelium discoideum. The antibiotic inhibits RNA synthesis in growing cells and in inactivated spores, and in this way inhibits spore germination. Protein synthesis is much less inhibited. Nogalamycin inhibits ribosomal RNA, transfer RNA, and messenger RNA equally. Polysomes break down in the presence of the drug with a half-life of 220 min, and messenger RNA decays with a half-life of 290 min. The data show that nogalamycin can be employed to inhibit messenger RNA synthesis and is useful in determining messenger RNA decay rates in the slime mold.

Daunorubicin↗
PubMed1971

Changes in hepatic glycogen, protein, and ribonucleic acid synthesis, and some effects of cortisol, during Q fever.

Liver glycogen is depleted in guinea pigs infected with Coxiella burneti. Syntheses of the glycogen precursors uridine triphosphate and uridine diphosphate glucose are unaffected during Q fever, but glycogen synthetase activity is inhibited. Exogenous cortisol relieves this inhibition in infected animals. Orotate and amino acids are more rapidly incorporated into ribonucleic acid and protein during infection. It is proposed that the biochemical defect in the synthesis of glycogen lies in the inactivation of glycogen synthetase.

Adenosine Triphosphate↗
PubMed1976

Recognition properties of the beta subunit of Escherichia coli ribonucleic acid polymerase.

Changes in the phage protein patterns obtained by gel electrophoresis of extracts from phage S13 and phiX174 infection of rifampin-resistant hosts suggest that the beta subunit of ribonucleic acid polymerase of Escherichia coli has a function in the recognition of promoter or terminator sites or both. The altered protein patterns also provide information on the location of some ribonucleic acid polymerase recognition signals in S13 deoxyribonucleic acid. There is a promoter site before gene A, which lies either in gene H or between H and A. There is evidence for a promotor between genes C and D or in gene C. There is either a terminator or a promoter somewhere between the end of gene D and the beginning of gene F.

Bacterial Proteins↗
PubMed1972

Inhibition of early vaccinia virus ribonucleic acid synthesis in interferon-treated chicken embryo fibroblasts.

Pretreatment of chicken embryo cells with homologous but not heterologous interferon inhibits the synthesis of vaccinia virus early messenger ribonucleic acid (mRNA). This inhibition is seen in the presence of cycloheximide, i.e., in the absence of protein synthesis, suggesting that the virion-bound transcriptase may be the target of the antiviral activity associated with interferon treatment. The inhibition of viral mRNA synthesis is dependent on the amount of chicken interferon used. The nonviral interferon inducer, polyriboinosine.polyribocytidine, similarly inhibits viral early mRNA synthesis in a dose-specific manner. The helical polynucleotide polydeoxyinosine.polyribocytidine, which is not an effective interferon inducer in chicken embryo cells, has no effect on viral ribonucleic acid synthesis.

Animals↗
PubMed1971

Electron microscopy of the altered spore morphology of a ribonucleic acid polymerase mutant of Bacillus subtilis.

Electron microscopy was used to analyze sporulating cells and spores of Bacillus subtilis mutants (Rif(r)) which are resistant to rifampin, an inhibitor of ribonucleic acid polymerase. The spores of Rif-18 are pleomorphic and frequently exhibit terminal knobs. These knobs first occur during late stage IV and early stage V of sporulation and are extensions of the inner and outer spore coats. Since the rifampin resistance and altered spore morphology of Rif-18 are 100% cotransformable, these data suggest that the altered spore morphology is the result of an alteration in ribonucleic acid polymerase genes. The morphology and physical dimensions are also reported for spores from Rif-11, Rif-15, and Rif-21. Significant differences in size from the wild type were observed for these mutants.

Bacillus subtilis↗
PubMed1976

Transcription from complementary deoxyribonucleic acid strands in various sporogenic and asporogenic mutants of Bacillus subtilis. Hybridization-competition studies on ribonucleic acid synthesized in vivo by a thermosensitive sporulation mutant (ts-4).

The present paper describes an investigation, at the transcription level, in a thermosensitive sporulation mutant of Bacillus subtilis (ts-4) grown at the permissive (30 degrees C) or restrictive (42 degrees C) temperature where sporulation capacity is respectively expressed or arrested. These studies were carried out by analysing the ribonucleic acid from vegetative and stationary phase cells (t3 cells) grown under both conditions, by hybridization-competition experiments.

Bacillus subtilis↗
PubMed2002

CD4 response is correlated with peak plasma concentrations of indinavir in adults with undetectable human immunodeficiency virus ribonucleic acid.

We retrospectively evaluated correlates of increases in CD4 cell count in antiretroviral agent-naive subjects with fewer than 50 copies per milliliter of plasma human immunodeficiency virus ribonucleic acid who were participating in a study of indinavir, lamivudine, and zidovudine therapy. Pharmacologic data from intensive pharmacokinetic studies and baseline patient characteristics were evaluated as predictors of the increase in CD4 count from baseline to weeks 24, 56, and 80. Relations were investigated with regression analysis. Of all covariates, maximum plasma concentration (C(max)) of indinavir was significantly and uniquely associated with increases in CD4 count from baseline to all end points (P =.002 at week 80; n = 20). At week 80, subjects with a C(max) greater than the overall group median value of 7 microg/ml had an increase in CD4 count of 358 cells/microl versus 197 cells/microl for those with a C(max) less than 7 microg/ml (P =.006). These data suggest distinct pharmacodynamic relations exist for immune reconstitution and suppression of plasma human immunodeficiency virus ribonucleic acid. We hypothesize this new finding may be associated with expression of P-glycoprotein.

Adult↗
PubMed1966

Effect of trypsin and ribonuclease on the immunogenic activity of ribosomes and ribonucleic acid isolated from Mycobacterium tuberculosis.

Youmans, Anne S. (Northwestern University Medical School, Chicago, Ill.), and Guy P. Youmans. Effect of trypsin and ribonuclease on the immunogenic activity of ribosomes and ribonucleic acid isolated from Myobacterium tuberculosis. J. Bacteriol. 91:2146-2154. 1966.-The ribosomal fraction of the attenuated strain, H37Ra, of Mycobacterium tuberculosis was treated with trypsin alone, ethylenediaminetetraacetic acid (EDTA) alone, EDTA and pancreatic ribonuclease, or with trypsin and ribonuclease. After each of these treatments, the ribosomal fractions were injected intraperitoneally into male CF-1 mice to test their capacity to produce an immune response to infection with virulent tubercle bacilli, strain H37Rv. Removal of protein with trypsin left the immunogenicity unchanged; EDTA alone reduced immunogenicity in the smaller vaccinating doses; EDTA plus ribonuclease reduced the immunogenicity by approximately 50% in the highest (1.0 mg) vaccinating dose; ribonuclease alone, after treatment with trypsin, reduced immunogenicity also approximately 50%. A crude mycobacterial ribonucleic acid (RNA) was prepared by extraction of the ribosomal fraction with alcohol. This RNA preparation was as effective in producing an immune response as the ribosomal fraction from which it was prepared, unless the RNA was partially or completely degraded during the preparation. The effect of ribonuclease on the immunogenicity of the RNA was similar to that obtained with the ribosomal fractions, except that ribonuclease completely destroyed the immunogenicity of a partially degraded RNA. RNA appears to be an essential part of an immunizing substance in attenuated tubercle bacilli, which produces a high degree of immunity in mice; 50 mug (dry weight) will protect approximately 80% of the mice, and as little as 0.5 mug will protect approximately 30% of the mice. Mycobacterial RNA not incorporated in Freund's incomplete adjuvant was nonimmunogenic. Yeast RNA incorporated in Freund's incomplete adjuvant was not immunogenic.

Animals↗
PubMed1977

Bacterial lipopolysaccharide induction of a mouse spleen factor stimulating ribonucleic acid polymerase II.

When bacterial lipopolysaccharide, a B-cell mitogen, was injected intraperitoneally into mice, the rate of deoxyribonucleic acid synthesis and the number of antibody-secreting cells in the spleen increased simultaneously, reaching a maximum in 3 days. The rate of ribonucleic acid synthesis also increased during this period, and this was found to be due to activation of alpha-amanitin-sensitive transcription in lymphoid cells of the spleen. The factors stimulating ribonucleic acid polymerase II in the spleens of normal mice and those treated with lipopolysaccharide were compared, and an additional factor besides that present in normal spleens was found in the spleen of lipopolysaccharide-treated mice.

Animals↗
PubMed1977

Threonyl-transfer ribonucleic acid synthetase from Escherichia coli: subunit structure and genetic analysis of the structural gene by means of a mutated enzyme and of a specialized transducing lambda bacteriophage.

Threonyl-transfer ribonucleic acid synthetase (ThrRS) has been purified from a strain of Escherichia coli that shows a ninefold overproduction of this enzyme. Determination of the molecular weight of the purified, native enzyme by gel chromatography and by polyacrylamide gel electrophoresis at different gel concentrations yielded apparent molecular weight values of 150,000 and 161,000, respectively. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate yields a single protein band of 76,000-dalton size. From these results an alpha(2) subunit structure can be inferred. A mutant with a structurally altered ThrRS, which had been obtained by selection for resistance against the antibiotic borrelidin, was used to map the position of the ThrRS structural gene (thrS) by P1 transductions. It was found that thrS is located in the immediate neighborhood of pheS and pheT, which are the structural genes for the alpha and beta subunits of phenylalanyl-transfer ribonucleic acid (tRNA) synthetase, the gene order being aroD-pheT-pheS-thrS. A lambda phage that was previously shown to specifically transduce pheS, pheT, and also the structural gene for the translation initiation factor IF3 can complement the defect of the altered ThrRS of the borrelidin-resistant strain. This phage also stimulates the synthesis of the 76,000, molecular-weight polypeptide of ThrRS in ultraviolet light-irradiated. E. coli cells. These results indicate that the genes for ThrRS, alpha and beta subunits of phenylalanyl-tRNA synthetase, and initiation factor IF3 are immediately adjacent on the E. coli chromosome.

Amino Acyl-tRNA Synthetases↗
PubMed1994

Vesicle-associated double-stranded ribonucleic acid genetic elements in Agaricus bisporus.

Double-stranded ribonucleic acids (dsRNAs) were isolated from fruit bodies of commercial strains of the cultivated mushroom (Agaricus bisporus) by polyethylene glycol-NaCl precipitation, differential centrifugation, rate-zonal centrifugation in sucrose, and equilibrium centrifugation in cesium sulphate. In all seven of the mushroom isolates examined, three dsRNAs were identified: two major dsRNA segments of > 13.1-kb (L-RNA) and 2.4-kb (S-RNA) and a minor segment of 5.2-kb (M-RNA). L-, M-, and S-RNAs co-purified with spherical fungal vesicles measuring approximately 75 nm in diameter. The three dsRNAs were intimately associated with the vesicles as suggested by their lower buoyant density in cesium sulphate (1.27 g/cc) compared to that of phenol-extracted dsRNAs (1.42 g/cc) and by their resistance to hydrolysis by ribonuclease at low ionic strength. Using a variety of conditions during purification, no virus-like particles were found to be associated with the dsRNAs. In Northern analysis, L-, M-, and S-RNAs failed to cross-hybridize with the genomic dsRNAs of La France isometric virus. We report here the first description of non-encapsidated, vesicle-associated, dsRNA genetic elements in the common cultivated mushroom.

Basidiomycota↗