The effect of whole-body X-irradiation of guinea pigs on liver ribosomes

Hidvégi, Egon J.; Holland, John J.; Bölöni, Erzsébet; Lonai, Peter; Antoni, Ferenc András; Varteresz, V.

doi:10.1042/bj1090495

Cited by 36 publications

(6 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…RER showed early reversal of these tnorphologic changes, and free ribosomes, the predominant form of cytoplasmic RNA in the basal cells, rctnained essentially unaltered. Although free ribosomes have been reported decreased iti some studies (Quastler & Hampton 1962, Hampton 1966) and increased in others (Hidvegi et al 1968, 1970, Unger & Hidvegi 1971, their apparent changes in concentration in our tnaterial merely seemed to reflect the changes in cytoplasmic volume. It is possible that similar fluctuations in cell volume contributed to the variable findings in other tissues.…”

Section: Cotnparison With Other Tissuesmentioning

confidence: 51%

An ultrastructural study of the effects of x‐irradiation on the oral epithelium of the rat: Qualitative aspects

Liu

Meyer

Waterhouse

1976

J Oral Pathology Medicine

View full text Add to dashboard Cite

Adult male rats of Simonsen strain were given a dose of 5000 r at 50 peak KV of x-irradiation directed at the lower lip, which was everted through a hole in a lead rubber cylinder shielding the head and body of the animal. Light and electron microscopic observations were made on specimens of lip oral mueosa from animals killed at 2, 6, 26 and 50 h and at 12 days after irradiation. The experimental model met the aim of permitting the study of the sequential effects of a high dose of irradiation without causing ulceration of the mueosa.Widespread degenerative changes were noted in the basal cells as early as 2 h after x-irradiation, increasing in degree up to 50 h. They included inflation of the outer nuclear envelope and rough endoplasmie retieulum (RER) with loss of ribosomes, swelling of mitoehondria and disarrangement of cristae evident at 2 h, followed at 6 h by swelling of nucleus and cytoplasm and 26 h by frank membrane breaks. Irreversible degrees of damage were noted in a small though growing minority of cells. Immediate mobilization of the Golgi-lysosomal system was evident as an increase in size of the zone, maximal at 2 h, and subsequent autophagic activity. Signs of recovery, beginning at 26 h, were noted in nuclear envelope, RER, intercellular space, and in mitotie activity by 50 h. Virtually complete recovery was seen at 12 days.It is held that the successful eonfinement of irradiation to a small tissue volume, the effective activity of the lysosomal system and the short epithelial turnover time were important factors in limiting the damage and in permitting recovery.

show abstract

Section: Cotnparison With Other Tissuesmentioning

confidence: 51%

An ultrastructural study of the effects of x‐irradiation on the oral epithelium of the rat: Qualitative aspects

Liu

Meyer

Waterhouse

1976

J Oral Pathology Medicine

View full text Add to dashboard Cite

show abstract

“…In our experiments we did not find this enzyme in the cytosol fraction obtained by a glycerol method [18], minimizing leakage of nuclear components. Therefore, in agreement with Rose et al [14] we conclude that most likely this poly(A) polymerase, although isolated from the cytosol, is of nuclear origin.…”

Section: Discussionmentioning

confidence: 78%

“…In order to specify the cytoplasmic localization of the poly(A) polymerases studied in this paper we carried out experiments in which the cytosol and ribosomal enzymes were prepared from a cytoplasmic fraction obtained by the glycerol method for cell disruption and removal of nuclei [18]. In such cytosol preparations the major poly(A) polymerase (PC-I) was not present in the eluate obtained from the phosphocellulose column.…”

Section: Poly(a) Polymerases In the Cytoplasmic Fraction Obtained By mentioning

confidence: 99%

“…In some experiments the cytosol and ribosomal fractions were isolated by the use of the glycerol method [18]. The cells were subsequently washed with isotonic saline; hypotonic buffer (10 mM Tris-HCI pH 7.6, 10 mM NaCl, 1.5 mM MgCI2, 2 mM 2-mercaptoethanol) and finally with 100 mM NaCI, 0.15 mM MgC12.…”

Section: Isolation Of Crude Cytosol and Ribosome-associated Enzymesmentioning

confidence: 99%

See 1 more Smart Citation

Two Distinct Poly(A) Polymerases Isolated from the Cytoplasm of Ehrlich Ascites Tumour Cells

Avramova¹,

Milchev²,

Hadjiolov³

1980

European Journal of Biochemistry

View full text Add to dashboard Cite

The poly(A) polymerases from the cytosol and ribosomal fractions of Ehrlich ascites tumour cells are isolated and partially purified by DEAE-cellulose and phosphocellulose column chromatography. Two distinct enzymes are identified : (a) a cytosol Mn2+-dependent poly(A) polymerase (ATP : RNA adenylyltransferase) and (b) a ribosome-associated enzyme defined tentatively as ATP(UTP) : RNA nucleotidyltransferase.The cytosol poly(A) polymerase is strictly Mn2+-dependent (optimum at 1 mM Mn2+) and uses only ATP as substrate, Poly(A) is a better primer than ribosomal RNA. The purified enzyme is free of poly(A) hydrolase activity, but degradation of [3H]poly(A) takes place in the presence of inorganic pyrophosphate. Most likely this enzyme is of nuclear origin.The ribosomal enzyme is associated with the ribosomes but it is found also in free state in the cytosol. The purified enzyme uses both ATP and UTP as substrates. The substrate specificity varies depending on ionic conditions: the optimal enzyme activity with ATP as substrate is at 1 mM Mn2+, while that with UTP as substrate is at 10-20 mM Mg2+. The enzyme uses both ribosomal RNA and poly(A) [but not poly(U)] as primers. The purified enzyme is free of poly(A) hydrolase activity.The problem of the post-transcriptionally added poly(A) sequences to the 3' end of pre-mRNA and mRNA is still controversial. This fact has stimulated the investigation of the enzymes catalyzing the addition of poly(A) tails to ribonucleotide primers, currently designated as poly(A) polymerases. Such enzymes have been detected in a variety of mammalian cells (reviews in [1,2]). The problem became more complicated when poly(A) polymerase activities were found not only in the nucleus but also in mitochondria1 [3 -51, ribosomal [6 -81 and cytosol[9 -131 fractions, although the possibility for a leakage of nuclear enzymes has to be considered in evaluating these findings [14]. Further, the terminal enzymatic addition of AMP residues to the 3' ends of poly(A)-containing RNA was found recently in the nuclei and in the cytoplasm. This reaction is apparently distinct from the de n o w poly(A) synthesis [15 -171. Thus, cellular metabolism of poly(A) sequences in pre-mRNA and mRNA seems to be more complex than inferred from current models. This paper is dedicated to Dr Fritz Lipmann on his 80th birthday.Ahbreviations. Poly(A)-containing RNA, RNA containing poly(A) sequences and retained by oligo(dT)-cellulose; poly(A)-lacking RNA, RNA not retained by oligo(dT)-cellulose.Enzymes. ATP : RNA adenylyltransferase or poly(A) polymerase (EC 2.7.7.19); ATP(UTP):RNA nucleotidyltransferase or poly(A) and poly(U) polymerase (EC 2.7.7-).In this work we report the isolation and partial purification of two distinct poly(A) polymerases from the cytoplasm of Ehrlich ascites tumour cells. The first one had an absolute requirement for Mn2+ and used only ATP as substrate. It was isolated from the cytosol but evidence was obtained that it is of nuclear origin. The second poly(A) polymerase was found associated with ribosom...

show abstract

“…Earlier investigations demonstrated enhanced RNA and protein synthesis in live shortly after whole-body X-irradiation of experimental animals (Hidvegi et al 1968(Hidvegi et al , 1978 . The enrichment of polysomes formed the structural basis of this enhancement (Hidvegi et al .…”

Section: Introductionmentioning

confidence: 97%

Inverse Correlation between Growth and Degrading Enzyme Activity of Seedlings after Gamma and Neutron Irradiation of Pea Seeds

Bagi

Bornemisza-Pauspertl

Hidvégi

1988

International Journal of Radiation Biology

View full text Add to dashboard Cite

The effect of gamma-, 14 MeV neutron- and fission neutron irradiation was investigated on the growth rate and degrading enzyme activities of pea seedlings. Both dormant pea seeds and 4-day-old growing seedlings were used for the experiments. Depending on the gamma dose between 15 and 300 Gy the height of pea seedlings was found shorter, and parallel with this the endogenous RNase and peroxidase activities were higher than in the unirradiated controls. Seedlings proved to be more sensitive by about one order of magnitude than seeds. Irradiation of seeds between 5 and 10 Gy slightly enhanced the growth rate of seedlings (10 per cent) and parallel with this, the RNase activity measured was lower than that in the controls. On irradiation of seedlings with 14 MeV neutrons the growth inhibition and RNase activity enhancement was only 1.3 times more effective than in the case of irradiation of seeds. The following RBE values were obtained after irradiation of seeds, related to the biological effect of gamma rays: in growth inhibition, 6 for 14 MeV neutrons and 12 for fission neutrons, and the enhancement of two enzyme activities was 15-30 for 14 MeV neutrons and 45-58 for fission neutrons. In the case of seedling irradiation with 14 MeV neutrons the RBE was 1.0 for growth inhibition and between 3 and 6 for enhancement of enzyme activity. The isoenzyme pattern of RNase also changed: two isoenzymes became predominant after the gamma irradiation of seeds, characterized by molecular weights of 21,000 and 30,000, respectively. As a result of enhanced RNase activity, the degradation of longer polysomes to monomeric ribosomes occurred. Thus after ionizing irradiation of pea seeds and seedlings an inverse correlation was found between the growth rate of pea seedlings and the activities of degrading enzymes.

show abstract

The effect of whole-body X-irradiation of guinea pigs on liver ribosomes

Cited by 36 publications

References 28 publications

An ultrastructural study of the effects of x‐irradiation on the oral epithelium of the rat: Qualitative aspects

An ultrastructural study of the effects of x‐irradiation on the oral epithelium of the rat: Qualitative aspects

Two Distinct Poly(A) Polymerases Isolated from the Cytoplasm of Ehrlich Ascites Tumour Cells

Inverse Correlation between Growth and Degrading Enzyme Activity of Seedlings after Gamma and Neutron Irradiation of Pea Seeds

Contact Info

Product

Resources

About