DNA Content Of Cell Nuclei Research Articles

Cytophotometric determination of DNA content in cell nuclei of the adrenal medulla, adrenal cortex and thyroid gland under various experimental conditions

Zur Frage funktioneller DNS-Veranderungen wurde der DNS-Gehalt von Zellkernen unter dem Einflus folgender verschiedener experimenteller Bedingungen an Rattenorganen zytophotometrisch bestimmt: 1. im Nebennierenmark nach intermittierender Kalteeinwirkung (300 Std), 2. im Bereich der Zona glomerulosa, Zona fasciculata, Zona reticularis der Nebennierenrinde nach ACTH bzw. Cortisonbehandlung, 3. in der Schilddruse nach Thyroxin, TSH bzw. Kaltebehandlung. Unter samtlichen Versuchsbedingungen blieb die DNS-Menge pro Zellkern in den verschiedenen Organen konstant. Eine Erhohung der Mittelwerte des DNS-Gehaltes in Nebennieren (ACTH) und Schilddrusen (TSH bzw. Kalte) ist durch S-Phasenzellkerne bedingt.

The Nucleic Acids and Cellular Differentiation in the Root Apex ofPisum sativum

The characteristic morphological development of cells from the inner stele, outer stele, and cortex of the pea root is accompanied by corresponding increases in RNA content. The increases are closely related to cell size but, in the outer stele at least, the increase is partly due to a rise in the RNA concentration. With the onset of vacuole development, the pattern of RNA increases is obscured. The DNA content of cell nuclei increase as cells enlarge, but these increases cannot be correlated with increases in cell volume.

The effect of some pituitary hormones on volume and DNA content of cell nuclei of the adrenal cortex in hypophysectomized-castrated rats

1. 1. The volume and the DNA content of the cell nuclei were determined by caryometry and Feulgen cytophotometry in the different layers of the adrenal cortex of the normal rat, the untreated hypophysectomized, castrated rat and the hypophysectomized, castrated rat treated by ACTH, STH and LH. 2. 2. Nuclear DNA content shows a decreasing gradient from the zona fasciculata externa to the zona reticularis. Nuclear volume shows the same pattern except in the zona glomerulosa, where nuclear volume is nearly half the volume of this in the zona fasciculata externa. 3. 3. After hypophysectomy nuclear DNA is decreased in the zona fasciculata externa, but unchanged in the other layers. Nuclear volume is decreased in every layer. 4. 4. Treatment by ACTH normalizes nuclear DNA in the zona fasciculata externa and increases this content in the two inner layers. Nuclear volume shows similar changes. 5. 5. Treatment by STH has no influence on nuclear DNA changes induced by hypophysectomy. Nuclear volume, however, is normalized in the zona glomerulosa and increased in the other layers. 6. 6. ICSH has no influence on the nuclear DNA content, but increases nuclear volume in every layer of the hypophysis-less rat. 7. 7. These results accord with the zonation theory. They support the hypothesis of Deane and Greep, who attribute a glucocorticoid function, depending on ACTH secretion, to the cells of the zona fasciculata externa, while the cell function of the zona glomerulosa is not dependent on ACTH secretion. The cells of the zona fasciculata interna and reticularis seem to be resting cells, which can be activated by high doses of ACTH. 8. 8. The volume of the nucleus is not only dependent on cell function, but also on other factors unrelated to specific cell function such as on the STH secretion of the hypophysis.

Microspectrophotometry of cell nucleus stained by Feulgen reaction: I. Microspectrophotometric apparatus without Schwarzschild-Villiger effect

The microspectrophotometric equipments hitherto employed for cytochemical analysis are not free from the Schwarzschild-Villiger effect (S-V effect), and the measured results contain errors which are sometimes so serious as to mislead to biological conclusions deduced from the measurements. The magnitude of the error due to the S-V effect and its influence on the determination of the DNA content in cell nuclei were theoretically estimated, and the theory was ascertained by several experiments. An improved optical system for microspectrophotometry was designed and constructed with succesful result to eliminate the S-V effect completely, and its details were described.