scholarly journals Quantitative analysis of rat liver nucleolar and nucleoplasmic ribosomal ribonucleic acids

1978 ◽  
Vol 171 (2) ◽  
pp. 367-374 ◽  
Author(s):  
M D Dabeva ◽  
K P Dudov ◽  
A A Hadjiolov ◽  
A S Stoykova
Keyword(s):  
Gel Electrophoresis ◽  
Molar Ratio ◽  
Absolute Amount ◽  
Agar Gel ◽  
Ribonucleic Acids ◽  
Nuclear Rna ◽  
Rrna Species ◽  
Detergent Treatment ◽  
Agar Gel Electrophoresis ◽  
Nucleolar Rna

rRNA from detergent-purified nuclei was fractionated quantitatively, by two independent methods, into nucleolar and nucleoplasmic RNA fractions. The two RNA fractions were analysed by urea/agar-gel electrophoresis and the amount of pre-rRNA (precursor of rRNA) and rRNA components was determined. The rRNA constitutes 35% of total nuclear RNA, of which two-thirds are in nucleolar RNA and one-third in nucleoplasmic RNA. The identified pre-rRNA components (45 S, 41 S, 39 S, 36 S, 32 S and 21 S) are confined to the nucleolus and constitute about 70% of its rRNA. The remaining 30% are represented by 28 S and 18 S rRNA, in a molar ratio of 1.4. The bulk of rRNA in nucleoplasmic RNA is represented by 28 S and 18 S rRNA in a molar ratio close to 1.0. Part of the mature rRNA species in nucleoplasmic RNA originate from ribosomes attached to the outer nuclear membrane, which resist detergent treatment. The absolute amount of nuclear pre-rRNA and rRNA components was evaluated. The amount of 32 S and 21 S pre-rRNA (2.9 × 10(4) and 2.5 × 10(4) molecules per nucleus respectively) is 2-3-fold higherthan that of 45 S, 41 S and 36 S pre-rRNA.

scholarly journals Differential stability of 28s and 18s rat liver ribosomal ribonucleic acids

1969 ◽  
Vol 115 (1) ◽  
pp. 91-94 ◽  
Author(s):  
P. V. Venkov ◽  
A. A. Hadjiolov
Keyword(s):  
Rat Liver ◽  
Gel Electrophoresis ◽  
18S Rrna ◽  
Heterogeneous Material ◽  
28S Rrna ◽  
Agar Gel ◽  
Ribonucleic Acids ◽  
Different Temperatures ◽  
Rrna Species ◽  
Agar Gel Electrophoresis

Rat liver ribosomal RNA (rRNA) free from nuclease contaminants was isolated by a modification of the phenol technique. The 28s and 18s rRNA species were separated by preparative agar-gel electrophoresis. The two rRNA species were heated at different temperatures under various conditions and the amount of undegraded rRNA was determined by analytical agar-gel electrophoresis. The 18s rRNA remained unaltered after heating for up to 10min. at 90° in water, acetate buffer, pH5·0, or phosphate buffer, pH7·0. Under similar or milder conditions 28s rRNA was partially degraded, giving rise to a well-delimited 6s peak and a heterogeneous material located in the zone between 28s and 6s. The dependence of degradation of 28s rRNA on the temperature and the ionic strength of the medium was studied. The greatest extent of degradation of 28s rRNA was observed on heating at 90° in water. It is suggested that the instability of rat liver 28s rRNA is due to two factors: the presence of hidden breaks in the polymer chain and a higher susceptibility of some phosphodiester bonds to thermal hydrolysis.

POLYETHYLENE GLYCOL ON AGAR-GEL ELECTROPHORESIS

The Lancet ◽  
1974 ◽  
Vol 304 (7892) ◽  
pp. 1321-1322
Author(s):  
W.H. Taylor ◽  
D.J. Etherington
Keyword(s):  
Polyethylene Glycol ◽  
Gel Electrophoresis ◽  
Agar Gel ◽  
Agar Gel Electrophoresis

Effect of Irradiation on the Biosynthesis of Liver Ribonucleic acids in Intact and Adrenalectomized Rats

1971 ◽  
Vol 26 (12) ◽  
pp. 1282-1287 ◽  
Author(s):  
P. G. Popov ◽  
L. I. Valeva-Dimitrova ◽  
A. A. Hadjiolov
Keyword(s):  
Rna Synthesis ◽  
Whole Body ◽  
Agar Gel ◽  
Ribonucleic Acids ◽  
Cytoplasmic Rna ◽  
Combined Action ◽  
Agar Gel Electrophoresis ◽  
Uridine Nucleotides ◽  
Adrenalectomized Rats ◽  
Hydrocortisone Treatment

Intact and adrenalectomized rats were irradiated with 900 R or treated with 10 mg per 100 g body weight of hydrocortisone. The incorporation of orotic acid-6-14C for 2 hours into liver free uridine nucleotides, nuclear and cytoplasmic RNA and RNA fractions obtained by agar gel electrophoresis, were studied.The obtained results show that in intact animals both irradiation and hydrocortisone induce a higher labelling of cytoplasmic and nuclear liver RNA. The higher labelling of RNA is not correlated with a higher labelling of the free uridine nucleotides. The labelling of all electrophoretic RNA fractions is increased to approximately the same extent under the action of either hydrocortisone or irradiation.Irradiation or hydrocortisone treatment of adrenalectomized rats causes also a higher labelling of liver nuclear and cytoplasmic RNA. The higher labelling of RNA is not correlated with that of free uridine nucleotides and affects all electrophoretic RNA fractions.. The combined action of irradiation and hydrocortisone shows an additive effect on the labelling of nuclear and cytoplasmic liver RNA.The obtained results indicate that whole body irradiation causes an increased synthesis of both ribosomal and non-ribosomal RNA’s of rat liver. Since the same effect is observed in intact and adrenalectomized animals it may be concluded that the stimulation of liver RNA synthesis by irradiation is not mediated by the adrenals.

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