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At least 577 records · Page 32Linked to original sources
PubMed1971

Asymmetric template function of microbial deoxyribonucleic acids: transcription of messenger ribonucleic acid.

In Bacillus subtilis and Escherichia coli, pulse-labeled ribonucleic acid (RNA) synthesized during step-down growth hybridized preferentially with the heavy (H) strand of methylated albumin-Kieselguhr-fractionated deoxyribonucleic acid (DNA). At high RNA inputs, the ratio of RNA hybridized with the H strand to that hybridized with the light (L) strand was 8.7 for B. subtilis and 2.0 for E. coli. At high DNA inputs, the H/L hybridization ratio increased by a factor of two. This change in the hybridization ratio was attributable to the fraction of the pulse-labeled RNA which is in stable RNA components. The hybridization peak of pulse-labeled RNA was specifically located in the late-eluting region of the absorbance profile of the H strand. This region was considered to represent the most actively transcribing H strand templates.

Bacillus subtilis↗
PubMed1974

Effect of preirradiation ribonucleic acid synthesis inhibition on resistance to ultraviolet light with resistant and sensitive strains of Escherichia coli B-r.

The ultraviolet resistance of a streptolydigin-susceptible strain of Escherichia coli B/r hcr(-) increased during preirradiation treatment with streptolydigin (an inhibitor of deoxyribonucleic acid-dependent ribonucleic acid polymerase) for 20 min and then remained constant. During preirradiation treatment with chloramphenicol (an inhibitor of protein synthesis), resistance to ultraviolet light increased for 1 to 2 h, and reached a maximal level significantly above that attained in streptolydigin-containing medium. These results suggest that there are two mechanisms that function in Hcr(-) cells during chloramphenicol treatment which contribute to the concomitant ultraviolet resistance enhancement. One is ribonucleic acid dependent and is inhibited by streptolydigin. This ribonucleic acid-dependent mechanism appears to be absent in wild-type and RecA E. coli B/r strains.

Agar↗
PubMed1969

Amino acid regulation of messenger ribonucleic acid synthesis in T4-infected Escherichia coli.

The effect of amino acid starvation on the synthesis of T4 messenger ribonucleic acid (mRNA) was studied by measuring the uptake of labeled precursors into Escherichia coli cells which were infected prior to amino acid starvation. The results indicated that the rate of uptake of labeled uracil and adenine into T4 mRNA was reduced by approximately 50% when amino acids were withheld from stringent K-12 strains, but not when they were withheld from a stringent strain B or a relaxed strain K-12. Chloramphenicol reversed the inhibition of precursor uptake resulting from amino acid starvation in the RC(str) K-12 strain. Pulse-labeling experiments reinforced these observations. Pulse-decay experiments in conjunction with actinomycin D indicated that the observed pattern of precursor uptake was probably not due to differences in mRNA decay rate. It is concluded that if amino acids exert any direct effect on the synthesis of T4 mRNA such an effect is much smaller than that observed for bulk RNA synthesis in the uninfected cell. These experiments also indicated that actual translation of the genetic message is not necessary for its transcription.

Adenine↗
PubMed1981

Arylhydroxylamine-induced ribonucleic acid chain cleavage and chromatographic analysis of arylamine-ribonucleic acid adducts.

Reaction of N-hydroxy-2-aminofluorene (N-OH-AF) with rRNA at pH 5.0 decreased the molecular weight of the polynucleotide. Toluene-soluble aryl derivatives were released on hydrolysis of fluorenylamine- and biphenylamine-substituted RNA by treatment with venom phosphodiesterase and alkaline phosphatase. These data suggested that arylhydroxylamines, activated by incubation at pH 5.0 or by enzymatic O-acetylation, might react with the phosphate group of RNA to give unstable phosphate triesters. Spontaneous hydrolysis of these triesters would result in cleavage of the polynucleotide chain. Further enzymatic hydrolysis of the phosphate esters would yield nonpolar arylamine derivatives. Enzymatically degraded 4-aminobiphenyl(ABP)-RNA adducts were examined by high performance liquid chromatography (HPLC) for the presence of a putative phosphorylated adduct. Synthetic standards of the C-8-guanosine monophosphate-ABP adduct (ABP-GMP) and o-aminobiphenyl-O-phosphate were used as markers in the analysis of the digested RNA. A phosphate adduct of ABP was undetectable by these methods. The data also indicated that the ABP-GMP formed in the acyltransferase-mediated binding of N-hydroxy-4-acetylaminobiphenyl (N-OH-AABP) to RNA is readily degraded during the enzymatic digestion of the RNA adduct.

Amines↗
PubMed1971

Methylation of newly synthesized ribonucleic acid by isolated rat liver nuclei. Characterization of the ribonucleic acid synthesized by nuclei from starved animals.

1. Nuclei from rat liver incubated with S-adenosyl[methyl-(14)C]methionine incorporated radioactivity into RNA and into lipid and protein. 2. All of the labelled RNA was extracted from the nuclei with trichloroacetic acid at 90 degrees C. 3. The [(14)C]methyl-group incorporation into the hot-trichloroacetic acid extract was 30% inhibited by the addition of actinomycin D (100mug/mg of DNA) or by the omission of CTP, GTP and UTP. 4. Assuming that the main substrate for this triphosphate-dependent methylation was newly synthesized precursor rRNA containing one methyl group/30 uridylate residues, it was calculated that approx. 60% of the [(14)C]UMP incorporated under similar conditions represented precursor rRNA synthesis. 5. In agreement with this, low concentrations of actinomycin D (approx. 1mug/mg of DNA) sufficient to abolish the triphosphate-dependent incorporation of [(14)C]methyl group inhibited 68% of the [(14)C]UMP incorporation. 6. The incorporation of [(14)C]UMP by nuclei from starved animals decreased progressively with increasing periods of starvation, whereas the triphosphate-dependent [(14)C]methyl-group incorporation was not further decreased after 1 day of starvation. 7. This suggests that precursor rRNA synthesis decreased within 1 day whereas other species of RNA were affected only after longer periods of starvation.

Animals↗
PubMed1972

The control of ribonucleic acid synthesis in bacteria. The synthesis and stability of ribonucleic acids in relaxed and stringent amino acid auxotrophs of Escherichia coli.

The biosynthesis and stability of various RNA fractions was studied in RC(str) and RC(rel) multiple amino acid auxotrophs of Escherichia coli. In conditions of amino acid deprivation, RC(str) mutants were labelled with exogenous nucleotide bases at less than 1% of the rate found in cultures growing normally in supplemented media. Studies by DNA-RNA hybridization and by other methods showed that, during a period of amino acid withdrawal, not more than 60-70% of the labelled RNA formed in RC(str) mutants had the characteristics of mRNA. Evidence was obtained for some degradation of newly formed 16S and 23S rRNA species to heterogeneous material of lower molecular weight. This led to overestimations of the mRNA content of rapidly labelled RNA from such methods as simple examination of sucrose-density-gradient profiles. In RC(rel) strains the absolute and relative rates of synthesis of the various RNA fractions were not greatly affected. However, the stability of about half of the mRNA fraction was increased in RC(rel) strains during amino acid starvation, giving kinetics of mRNA labelling and turnover that were identical with those found in either RC(str) or RC(rel) strains inhibited by high concentrations of chloramphenicol. Coincidence hybridization techniques showed that the mRNA content of amino acid-starved RC(str) auxotrophs was unchanged from that found in normally growing cells. In contrast, RC(rel) strains deprived of amino acids increased their mRNA content about threefold. In such cultures the mRNA content of accumulating newly formed RNA was a constant 16% by wt.

Amino Acids↗
PubMed1975

Maturation pathway for Novikoff ascites hepatoma 5.8 S ribosomal ribonucleic acid. Evidence for its presence in 32 S nuclear ribonucleic acid.

Evidence that 32 S nRNA contains 5.8 S rRNA was provided by studies on specific oligonucleotide sequences of these RNA species. Purified 32P-labeled 5.8 and 28 S rRNA and 32 S RNA were digested with T-1 ribonuclease, and the products were fractionated according to chain length by chromatography on DEAE-Sephadex A-25 at neutral pH. The oligonucleotides in Peak 8 were treated with alkaline phosphatase and the products were separated by two-dimensional electrophoresis on cellulose acetate at pH 3.5 and DEAE-paper in 7% formic acid. Seven unique oligonucleotide markers for 5.8 S rRNA including the methylated octanucleotide A-A-U-U-Gm-G-A-Gp were present in 32 S RNA but were not found in 28 S rRNA, indicating that 5.8 S rRNA is directly derived from the 32 S nucleolar precursor. These studies confirm a maturation pathway for rRNA species in which 32 S nucleolar RNA is a precursor of 5.8 S rRNA as well as 28 S rRNA.

Alkaline Phosphatase↗
PubMed1988

A comparison of biotin and isotope-labeled ribonucleic acid probes for in situ detection of HPV-16 ribonucleic acid in genital precancers.

Genital precancers were analyzed by in situ hybridization for the presence of HPV RNA using single-stranded RNA probes. To compare the sensitivity of biotin- and 35S-labeled probes, serial sections from three biopsies containing variable amounts of HPV 16 RNA were analyzed with probes containing each label. The probe template was a cloned fragment of the HPV 16 genome spanning portions of the E2, E5 and L2 orf's. When a focus contained a strong hybridization signal with 35S-labeled probes (i.e., target/background ratio greater than 40) serial sections of the same area usually demonstrated a strongly positive signal with biotin-labeled probes. When the signal with 35S in a given focus was weak (target/background ratio less than 20), serial sections contained either a very weak or no detectable signal with the biotinylated probe. From this study it appears than 35S-labeled RNA probes exceed the sensitivity of biotin-labeled probes by nearly an order of magnitude with short exposures (4 days), and with longer exposures (1 to 2 weeks), approach the sensitivity of that reported for tritiated probes and exposures of 1 month or longer.

Biotin↗