Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “RIBONUCLEIC ACID”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,369 records · Page 76Linked to original sources
PubMed1979

Ribosomal ribonucleic acid isolated from Salmonella typhimurium: absence of the intact 23S species.

Ribonucleic acid (RNA) isolated by four distinct methods and from a variety of Salmonella typhimurium strains lacked intact 23S ribosomal RNA (rRNA). On sucrose gradients which minimize aggregation, the vast majority of S. typhimurium rRNA sedimented as a 16S peak with a 14S shoulder. RNA from this region of the gradient was resolved into three discrete bands by electrophoresis in formamide. Two very minor S. typhimurium RNA peaks were resolved at 21S and 10S on sucrose gradients, and each peak formed discrete bands in electrophoresis. It is concluded that if S. typhimurium does possess an intact 23S rRNA species, this species is extremely "labile." The absence of isolatable S. typhimurium 23S rRNA possibly reflected in vivo processing of the rRNA before isolation. Under certain conditions, S. typhimurium rRNA formed discrete aggregates which sedimented similarly to intact Escherichia coli 23S rRNA.

Centrifugation, Density Gradient↗
PubMed1979

Organization of transfer and ribosomal ribonucleic acid genes in Bacillus subtilis.

The structural relationship between the transfer ribonucleic acid (tRNA) and the ribosomal RNA (rRNA) genes of Bacillus subtilis has been studied by restriction endonuclease analysis of total chromosomal deoxyribonucleic acid (DNA) and characterization of DNA fragments cloned in Escherichia coli. The DNA sequences encoding rRNA and tRNA were assayed by hybridization to radioactive RNA. The results support the conclusion that the tRNA genes are interspersed between and closely linked to the rRNA genes of B. subtilis. They probably do not appear between the 16S and 23S rRNA genes as in E. coli.

Bacillus subtilis↗
PubMed1980

Pattern of ribonucleic acid synthesis during germination of Allomyces macrogynus mitospores.

The relationship between ribonucleic acid (RNA) synthesis and germination of Allomyces macrogynus mitospores was investigated. It was determined that the synthesis of all classes of RNA was initiated during the first 10 min of germination, around the time of encystment. It is during this stage that the membrane of the nuclear cap structure begins to break down, dispersing the cell complement of ribosomes throughout the cytoplasm. After encystment, there was an increase in the rate of synthesis of the four stable RNA species (4S, 5S, 19S, and 27S) which leveled off as the germ tube emerged. Data suggested that messenger RNA was synthesized at an increasing rate during the course of germination. Studies of RNA precursor pool behavior and RNA synthesis in the presence and absence of actinomycin D indicated that no species of RNA, including messenger RNA, was synthesized in the presence of actinomycin D. Further, precursor pool measurement indicated that the apparent increase in the rate of RNA synthesis during germination was largely due to increased specific activity of the RNA precursor pool.

Chytridiomycota↗
PubMed1980

Organization of transfer ribonucleic acid genes in the Escherichia coli chromosome.

The arrangement of transfer ribonucleic acid (RNA) genes in the chromosome of Escherichia coli K-12 (C600) was examined with the techniques of restriction endonuclease digestion and Southern blotting. The number and size of restriction fragments containing transfer or ribosomal RNA sequences or both were estimated by a variety of restriction endonucleases, including EcoRI, BglI, SmaI, SalI, BamHI, and PstI. EcoRI liberated a minimum of 27 fragments which hybridized to transfer RNA and 16 which hybridized to ribosomal RNA. Enzymes which did not cut within the ribosomal RNA operons (PstI and BamHI) liberated 16 and 13 fragments, respectively, which hybridized to transfer RNA. Five PstI and six BamHi fragments also hybridized to ribosomal RNA, suggesting that there may be at least 11 chromosomal locations distinct from ribosomal RNA operons which encode transfer RNA genes. In addition, our data indicated that several transfer RNA genes may be very close to the 5' proximal ends of certain ribosomal RNA operons and close to the 3' distal ends of all seven ribosomal RNA operons. Similar studies have been carried out with 22 purified species of transfer RNA, and we report here the number and size of EcoRI restriction fragments which hybridize to these transfer RNA species.

Base Sequence↗
PubMed1967

Metabolic properties of early and late vaccinia virus messenger ribonucleic acid.

In vaccinia-infected cells, 60% of the viral messenger ribonucleic acid (mRNA) was associated with polyribosomes, and the remainder sedimented in a broad peak in the 30 to 74S region. The quantity of mRNA in polyribosomes was sharply reduced late in the infectious cycle [9 hr postinfection (PI)] to less than 30% of the 2-hr value. However, protein synthesis proceeded at a nearly constant rate from 2 to 13 hr PI. This ability of small quantities of late mRNA to support as much protein synthesis as do the much larger quantities of early mRNA was not due to an increase in stability, since late mRNA decays with a half-life of 13 min, whereas early mRNA has a half-life of 120 min. A similar decrease in viral mRNA synthesis without an accompanying decrease in viral protein synthesis was observed when deoxyribonucleic acid synthesis is inhibited. In contrast to the rapid decay of the late mRNA which was present in polyribosomes, the mRNA which sedimented in the 30 to 74S region remained unchanged even after a 2-hr period of exposure to actinomycin. The rate at which infected cells lose the capacity to synthesize specific viral proteins after exposure to actinomycin D was consistent with the half-life values of early and late mRNA that were observed.

Centrifugation, Density Gradient↗
PubMed1967

Denaturation and renaturation of viral ribonucleic acd. II. Characterization of the products resulting from annealing R17 ribonucleic acid with denatured replicative form or with denatured replicative intermediate.

The ribonucleic acid (RNA) product resulting from annealing R17 RNA with denatured replicative form or replicative intermediate could be divided into two distinct types of RNA by precipitation in 1.5 m NaCl. The RNA found in the salt supernatant fluid was resistant to digestion by ribonuclease, had a sedimentation coefficient of 15S, and displayed a sharp thermal transition. The RNA in the salt supernatant fluid appeared to be identical to replicative form. The RNA found in the salt precipitate was resistant to digestion by ribonuclease, but possessed both single- and double-stranded characteristics. The RNA sedimented as a broad band in a sucrose gradient, with a sedimentation coefficient of 15S, and displayed a melting transition characteristic of a mixture of single- and double-stranded RNA. Mild ribonuclease digestion of the salt-precipitable RNA produced a ribonuclease-resistant material with sedimentation properties identical to the RNA found in the salt supernatant fluid.

Centrifugation, Density Gradient↗
PubMed1968

Ribonucleic acid synthesis in cells infected with influenza virus.

Virus-specific ribonucleic acid (RNA), synthesized in influenza virus-infected cells from 3.5 to 7.5 hr after infection, was studied. After velocity centrifugation in sucrose, three peaks of virus-specific RNA could be identified: 34S, 18S, and 11S. These RNA species are predominantly single-stranded and consist of 90% viral (plus) and 10% complementary (minus) RNA strands. Most (75%) of the complementary RNA is single-stranded, i.e., not part of RNA duplexes or replicative intermediates. The 34S RNA species is an aggregate of 18S and 14S RNA species. Both 18S and 11S RNA species are relatively heterogenous compared to 18S ribosomal RNA, and these species probably contain different RNA molecules having closely related sedimentation coefficients.

Animals↗
PubMed1969

Characterization of influenza virus ribonucleic acid duplex produced by annealing in vitro.

A ribonuclease-resistant ribonucleic acid (RNA) with a sedimentation coefficient of 12S was obtained by self-annealing influenza virus-specific RNA isolated from infected cells. It had the properties of double-stranded RNA. (i) Sedimentation behavior in sucrose gradient was independent of salt concentration. (ii) Thermal transition profile was sharp; the melting temperature is 83 C in 0.1 SSC (0.15 m NaCl plus 0.015 m sodium citrate) and 98 C in SSC. (iii) Buoyant density in cesium sulfate was 1.58 g/cm(3) compared to 1.64 g/cm(3) for single-stranded RNA. (iv) It gave rise to single-stranded RNA after denaturation. (v) The 12S RNA duplex contained both plus and minus strands of influenza virus. Labeled plus strands could be displaced by extraneous cold plus strands and extraneous (32)P-labeled plus strands could be incorporated into duplex after denaturation and reannealing.

Animals↗
PubMed1971

Influence of polycations on the interaction between poliovirus multistranded ribonucleic acid and HeLa cells.

In contrast to single-stranded viral ribonucleic acid (RNA), poliovirus multistranded RNA (RI-RNA) is poorly adsorbed to suspended HeLa cells in the absence of polycations. In the presence of 20 mug of diethylaminoethyl (DEAE) dextran per ml and other polycations, 90% or more of the RI-RNA is adsorbed to HeLa cells within 2 min at 37 C. However, only 30% of the RI-RNA label penetrates into the cells independent of the concentration of DEAE dextran applied. DEAE dextran is adsorbed almost quantitatively to HeLa cells within 3 min at 37 C. Most of the DEAE dextran remains bound to the cell membrane and available for binding of RI-RNA for 15 min at 37 C.

Adsorption↗
PubMed1981

Rates of synthesis and degradation of ribosomal ribonucleic acid during differentiation of Dictyostelium discoideum.

Synthesis of ribosomes and ribosomal ribonucleic acid (RNA) continued during differentiation of Dictyostelium discoideum concurrently with extensive turnover of ribosomes synthesized during both growth and developmental stages. We show here that the rate of synthesis of 26S and 17S ribosomal RNA during differentiation was less than 15% of that in growing cells, and by the time of sorocarp formation only about 25% of the cellular ribosomes had been synthesized during differentiation. Ribosomes synthesized during growth and differentiation were utilized in messenger RNA translation to the same extent; about 50% of each class were on polyribosomes. Ribosome degradation is apparently an all-or-nothing process, since virtually all 80S monosomes present in developing cells could be incorporated into polysomes when growth conditions were restored. By several criteria, ribosomes synthesized during growth and differentiation were functionally indistinguishable. Our data, together with previously published information on changes in the messenger RNA population during differentiation, indicate that synthesis of new ribosomes is not necessary for translation of developmentally regulated messenger RNA. We also establish that the overall rate of messenger RNA synthesis during differentiation is less than 15% of that in growing cells.

Dictyostelium↗
PubMed1979

Experimental and clinical studies on toxicity of xenogeneic tumor-specific immune ribonucleic acid.

To learn the toxicity of xenogeneic tumor-specific immune ribonucleic acid (I-RNA), experimental and clinical studies were carried out. Experimentally, doses of 30 mg/kg, 15 mg/kg, 7.5 mg/kg or 3.75 mg/kg of xenogeneic I-RNA extracted from lymphoid tissues of rabbits sensitized with 105,000 Xg sediments of human gastric carcinoma tissue were injected intraperitoneally into Wistar rats once a day for 30 days. During the period of the study, changes of physiological and biochemical values were examined. In addition, pathological study was made for each organ after the I-RNA administration. There was no death during the study. In the groups of high dose administration, there were poor increase in the body weight, elevation of GOT, GPT and LDH, findings of vacuolar degeneration of hepatic cells, and increase of mesangial matrix and polynuclear glomerulus. Throughout the experiment, the groups given 7.5 mg/kg and 3.75 mg/kg of I-RNA showed no significant difference from control groups. Clinically, 31 cases treated with passive immunotherapy with allogeneic lymphocytes, preincubated with xenogeneic I-RNA, were examined retrospectively for the difference in hematological and biochemical data before and after the therapy. One case showed a transient mild febrile reaction after the therapy. There was no significant difference in hematological and biochemical data. Pathological findings in 3 autopsies after the treatment were reported.

Adult↗
PubMed1979

Identification by affinity chromatography of the eukaryotic ribosomal proteins that bind to 5.8 S ribosomal ribonucleic acid.

The proteins that bind to rat liver 5.8 S ribosomal ribonucleic acid were identified by affinity chromatography. The nucleic acid was oxidized with periodate and coupled by its 3'-terminus to Sepharose 4B through and adipic acid dihydrazide spacer. The ribosomal proteins that associate with the immobilized 5.8 S rRNA were identified by polyacrylamide gel electrophoresiss: they were L19, L8, and L6 from the 60 S subunit; and S13 and S9 from the small subparticle. Small amounts of L14, L17', L18, L27/L27', and L35', and of S11, S15, S23/S24, and S26 also were bound to the affinity column, but whether they associate directly and specifically with 5.8 S rRNA is not known. Escherichia coli ribosomal proteins did not bind to the rat liver 5.8 S rRNA affinity column.

Animals↗
PubMed1995

Thyroids from siblings with Pendred's syndrome contain thyroglobulin messenger ribonucleic acid variants.

We studied thyroid tissue from two siblings with Pendred's syndrome (familial goiter and congenital deafness), both with the Mondini-type inner ear malformation, goiter, and hypothyroidism. Iodine trapping and peroxidase levels were grossly normal. Thyroglobulin (Tg), the only iodoprotein found, had a normal monomer size (330 kilodaltons), but low content of hormone and iodine. Tg's expected N-terminal peptides of 26 and 18 kilodaltons, usually formed in association with iodination and thyroid hormone synthesis, were absent, but appeared after iodination in vitro. Reverse transcription of ribonucleic acid from Pendred thyroid tissue and amplification by polymerase chain reaction of specific regions encoding the most important hormonogenic sites of Tg revealed a normal complementary DNA sequence corresponding to the first 100 amino acid residues in Tg's N-terminus. However, 3 of 35 clones of the 3'-region corresponding to the Tg C-terminus exhibited a deletion of nucleotides 7860-7994; this deletion was not present in any of the 150 clones from 7 other thyroids we examined. Four Pendred clones had a 2-nucleotide deletion at positions 7870-7871, a change that would result in a premature stop codon and was found in thyroids from several other subjects as well. We conclude that the messenger ribonucleic acid encoding the 3'-region of Tg can be abnormal in Pendred's syndrome. Some, but not all, of these changes also occur in other human thyroids. Further work is necessary to show if and how these alterations relate to defective hormone synthesis and goiter.

Adult↗
PubMed1998

Oxytocin receptor and its messenger ribonucleic acid in human leiomyoma and myometrium.

OBJECTIVE: The study determined the expression of oxytocin receptor and its gene in human uterine leiomyoma compared with the adjacent myometrium. STUDY DESIGN: Paired samples of leiomyoma and the adjacent myometrium from 20 women through the menstrual cycle, menopause, and various hormone treatments were studied. Oxytocin receptor was immunohistochemically localized with use of the specific antibody (2F8) to human oxytocin receptor. Oxytocin receptor protein was determined by Western blotting, whereas reverse transcription-polymerase chain reaction was used for oxytocin receptor messenger ribonucleic acid expression. RESULTS: Immunohistochemistry showed positive staining in all tissues examined, relatively more intense in the myometrium than in the adjacent leiomyoma, and in tissues from the preovulatory than the postovulatory phase. Western blotting showed a single 70-kd band corresponding to the oxytocin receptor. The relative abundance of oxytocin receptor in both leiomyoma and myometrium was significantly higher during the preovulatory (n = 5) than the postovulatory (n = 5) phase (P = .034 and .05). In women receiving gonadotropin-releasing hormone agonist (n = 1) or oral contraceptives (n = 1), after the menopause (n = 2), and with irregular vaginal bleeding (n = 1), oxytocin receptor levels in leiomyoma and myometrium were unchanged but were reduced in anovulatory cycles (amenorrhea, n = 2). Reverse transcription-polymerase chain reaction showed messenger ribonucleic acid for oxytocin receptor as a 391-bp band in all leiomyomas and myometrium examined. CONCLUSIONS: Leiomyoma and myometrium express the gene and protein for oxytocin receptor, which is probably partially regulated by ovarian sex steroids during the menstrual cycle.

Adult↗
PubMed1999

Reduced growth hormone receptor messenger ribonucleic acid in an aged man with chronic malnutrition and growth hormone resistance.

A severely malnourished 87-yr-old man presented with hypoglycemia. Serum GH levels were elevated, and serum levels of insulin-like growth factor I (IGF-I), IGF-binding protein-3, and GH-binding protein were extremely reduced. The patient's GH was biologically active. Administration of GH for 4 consecutive days resulted in a slight increment in serum IGF-I levels, but no elevation of serum IGF-binding protein-3. The expression of GH receptor messenger ribonucleic acid in the liver was greatly reduced. An autopsy revealed a Rathke's cleft cyst confined to the sella turcica. Immunohistochemical studies for GH showed that there was nothing to suggest a tumor overproducing GH. In addition, TSH levels were elevated in the presence of normal thyroid hormone levels, and there was a cluster of cells showing strong immunohistochemical staining for the TSH beta-subunit in the pituitary. In this patient, the decreased expression of GH receptor messenger ribonucleic acid in the liver may have been responsible for the GH resistance, which was probably caused by malnutrition.

Aged↗
PubMed1981

Advanced nuclear magnetic resonance lanthanide probe analyses of short-range conformational interrelations controlling ribonucleic acid structures.

An advanced method was developed for lanthanide-probe analyses of the conformations of flexible biomolecules such as nucleotides. The new method is to determine structure parameters (such as internal-rotation angles) and population parameters for local conformational equilibria of flexible sites, together with standard deviations of these parameters. As the prominent advantage of this method, the interrelations among local conformations of flexible sites may be quantitatively elucidated from the experimental data of lanthanide-induced shifts and relaxations and vicinal coupling constants. As a structural unit of ribonucleic acids, the molecular conformations and conformational equilibria of uridine 3'-monophosphate in aqueous solution were analyzed. The stable local conformers about the C3'-O3' bond are the G+ (phi' = 281 +/- 11 degrees) and G- (phi' = 211 +/- 8 degrees) forms. The internal rotation about the C3'-O3' bond and the ribose-ring puckering are interrelated; 97 +/- 5% of the C3'-endo ribose ring is associated with the G- form while 70 +/- 22% o the C2'-endo ribose ring is associated with the G+ form. An interdependency also exists between the internal rotation about the C4'-C5' bond and the ribose-ring puckering. These short-range conformational interrelations are probably important in controlling the dynamic aspects of ribonucleic acid structures.

Chemical Phenomena↗
PubMed1995

Type 2 11 beta-hydroxysteroid dehydrogenase messenger ribonucleic acid and activity in human placenta and fetal membranes: its relationship to birth weight and putative role in fetal adrenal steroidogenesis.

Two isoforms of 11 beta-hydroxysteroid dehydrogenase (11 beta HSD) have been described which catalyze the interconversion of cortisol (F) to cortisone (E). 11 beta HSD activity has previously been reported in placenta and fetal membranes, where its role may be to protect the developing fetus from glucocorticoid excess. Furthermore, in the rat, an association between placental 11 beta HSD activity and the subsequent development of hypertension in the offspring has been reported. We have characterized the isoforms of 11 beta HSD in human fetal membranes and dissected placental tissue at term and investigated the relationship between placental 11 beta HSD activity and fetal and placental weights. 11 beta HSD activity studies in the presence of 0.1 mumol/L F and NAD (indicative of type 2 isoform activity) revealed high levels of activity in trophoblast dissected free of vessels (561 +/- 87 pmol E/h.mg protein; n = 4) > undissected placenta > cotyledenous vessels dissected away from trophoblast > placental and reflected amnion. In contrast, in the presence of 2.5 mumol/L F and NADP (indicative of type 1 isoform activity), only decidua and chorion demonstrated significant levels of 11 beta HSD activity. Type 1 11 beta HSD activity in chorion was probably due to decidual contamination, in that it was absent in decidua-free fused chorion obtained from a twin pregnancy. In keeping with these data, type 1 11 beta HSD messenger ribonucleic acid (1.5 kilobases) was detected in decidua, but in no other tissue, and high levels of type 2 11 beta HSD messenger ribonucleic acid (1.9 kilobases) were found in undissected placenta and trophoblast. In 27 term placentas, 11 beta HSD activity varied from 194-448 pmol E/h.mg protein. There was a weak, but significant, positive correlation between term placental 11 beta HSD activity and fetal weight (r = 0.408; P = 0.034), but no correlation with placental weight. Thus, in man, the reported association of a small fetus and a large placenta predisposing to adult hypertension cannot be explained on the basis of defective 11 beta HSD activity. However, the placenta offers an immense reservoir for F clearance (1.73-7.95 mumol/min.placenta) and may be a principal factor driving fetal ACTH secretion and, hence, fetal adrenal steroidogenesis.

11-beta-Hydroxysteroid Dehydrogenases↗