Cytophotometric studies on the cell nucleus

Frazer, Samuel C (1957) Cytophotometric studies on the cell nucleus. PhD thesis, University of Glasgow.

Abstract

The work reported is an investigation of the amounts of deoxyribonucleic acid (DNA) contained in individual cell nuclei from a number of animal tissues, the amounts being estimated by microspectrophotometric methods. PART I outlines the history of microscopy, and in particular the application of the quarts microscope, in the ultraviolet region of the spectrum, to biological specimens. Historical aspects of histochemistry and cytochomistry, and of quantitative microspoctrophotometric procedures, are also described, together with a brief review of the development of current knowledge of the nucleic acids. PART II consists of a critical survey of methods which have boon used for the estimation of deoxyribonucleic acid in single nuclei, and describes a photometric procedure for this purpose, based on density measurements on photomicrographic negatives. The procedure has been developed for use in either the visible or the ultraviolet regions of the Spectrum, and its application to the estimation of DNA by three distinct techniques is described. These methods are ultraviolet absorption measurements on unstained isolated nuclei visible light absorption measurements on Foulgen-stained nuclei; and visible light absorption measurements on nuclei following staining with methyl green. PART III presents the results of a series of comparative measurements of the DNA contents of single nuclei from a number of normal and abnormal tissues in the adult rat, and a small series of measurements on embryonic chick tissues. A statistical assessment of the significance of the differences between nuclei has been made. PART IV is a discussion of the results obtained, and of their significance in relation to the possible role of DNA as a chemical basis for the concept of the gene. It is concluded that in the rat the amount of DNA contained in diploid somatic nuclei is nearly constant, irrespective of the tissue of origin, although small differences between nuclei occur. In those rat tissues which have a proportion of tetraploid or octoploid nuclei, there are found nuclei having twice or four times the usual amount of DNA. Spermatozoa have approximately half that amount. The results are in keeping with the postulated role of DNA in the transmission of hereditary characters.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: J N Davidson
• Keywords: Cellular biology
• Date of Award: 1957
• Depositing User: Enlighten Team
• Unique ID: glathesis:1957-73683
• 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/73683