Nucleic acid studies on cell fractions

Logan, Robert (1956) Nucleic acid studies on cell fractions. PhD thesis, University of Glasgow.

Abstract

1. The incorporation of radioactive phosphorus (32P) into the phospholipids and ribonucleic acid (RNA) of the isolated nuclei, mitochondria, microsomes and cell sap and into the deoxyribonucleic acid (DNA) of the isolated nuclei of rabbit liver has been investigated at various time intervals after administration of the isotope. The nuclear RNA showed a greater uptake of than was found in the RNA of the cytoplasmic fractions. The uptake of into the RNA was approximately the same in the different cytoplasmic fractions. Maximum incorporation into the RNA of all fractions occurred about 24 hours after the administration of the Isotope. The incorporation of 32p into the DNA was very low and the maximum was reached about 18 hours after administration. 8. The incorporation of into the phospholipids and RNA of the liver cytoplasmic fractions of fowls, in different physiological states, was studied. No correlation was found between the physiological state of the birds and the incorporation of the isotope. 3. An ionophoretic separation of the nucleotides of the RNA fractions of rabbit and fowl livers was carried out. It was found that the specific activities of the nucleotides of any one RNA fraction were all of the same order. 4. The in vitro incorporation of inorganic 32P into the RNA of sucrose homogenates of rat liver was investigated. Such rat liver homogenates were found to be capable of incorporating into RNA in the presence of ATP, DPW, cytochrome c, Na2HPO4 and MgCl2. 5. It was found that isolated nuclei and whole cytoplasm of rat liver were each able to Incorporate 32P into their RNA fractions on incubation. Incorporation of inorganic 32p into the RNA of isolated mitochondria was also demonstrated, but no uptake of 32P into the RNA of isolated microsomes or cell sap was observed. 6. The transfer of 32P from radioactive cellular fractions into non-radioactive cellular fractions of rat liver, rat spleen, rabbit liver and rabbit intestinal mucosa was investigated. 7. Using rat liver, rat spleen and rabbit intestinal mucosa, it was found that there was a transfer of 32P from radioactive whole cytoplasm into the nucleic acids of non-radioactive nuclei. Ho evidence was obtained for the transfer of phosphorus from radioactive rat liver nuclei into the RHA of non-radioactive rat liver cytoplasm. However, in rat spleen and rabbit intestinal mucosa, it was observed that some transfer of 32P from the radioactive nuclei to non-radioactive cytoplasm occurred. 8. The transfer of 32p from radioactive cytoplasm to nonradioactive nuclei of rabbit intestinal mucosa was not inhibited by cyanide. 9. Investigation of the transfer of phosphorus from radioactive cyboplasmic components to non-radioactive nuclei of rabbit liver showed that cell sap was the best donor of phosphorus for Incorporation into nuclear nucleic acids. 10. Dialysis of radioactive cell sap, prior to incubation with non-radioactive nuclei of rabbit liver, partially inhibited the transfer of 32p into the nuclear nucleic acids. 11. Various phosphorus compounds, of the radioactive cell sap were investigated as possible donors of phosphorus for inclusion into the RNA and DNA of the nucleus. 12. Three protein fractions were obtained from radioactive cell sap, by ammonium sulphate fractionation. It was demonstrated that they differed in their abilities to promote the transfer of to the RNA and DNA of the nucleus.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: J N Davidson
• Keywords: Biochemistry
• Date of Award: 1956
• Depositing User: Enlighten Team
• Unique ID: glathesis:1956-73258
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 14 Jun 2019 08:56
• Last Modified: 14 Jun 2019 08:56
• URI: https://theses.gla.ac.uk/id/eprint/73258