The effects of ultraviolet light on the biological and physical chemical properties of deoxyribonucleic acids

Journal Article · Fri Dec 01 04:00:00 EST 1961 · Journal of Cellular and Comparative Physiology

DOI:https://doi.org/10.1002/jcp.1030580406· OSTI ID:4819742

Marmur, J.; Anderson, W. F.; Matthews, L.; Berns, K.; Gajewska, E.; Lane, D.; Doty, P.

When DNA is irradiated in solution with UV light at 254 m mu , loss of transforming activity and changes in the physical chemical properties of the DNA can be detected. The loss of biological activity, studied with DNA isolated from D. pneumoniae and B. subtilis, depends on the genetic marker under investigation as well as on its size and on the molecular weight of the DNA being irradiated. When exposed to higher dose levels, native DNA is both partially degraded and weakened in structure. Cross-linking of the complementary strands has been detected. The UV induced physical chemical alterations have been detected by the lowering of the denaturation temperature, a drop in sedimentation coefficient after denaturation, a decrease in viscosity, an increase in buoyant density in a CsCl gradient, a cross-linking of DNA strands and an increase in the pH at which the molecules denature. Most of the physical chemical changes are accentuated by a higher adenine plus thymine content of the DNA and by the substitution of 5bromouracil for thymine. Denatured and native DNA behave differently when exposed to the same dose at the same wavelength. As in the biological experiments, for the same dose levels, the smaller the molecular weight of the DNA, the less the physical chemical damage. Both the biological and the viscosity changes induced by UV show no oxygen effect. The photoreactivating enzyme from bakers' yeast reactivates UV-treated transforming DNA in the presence of visible light; the reactivation might be due in part to the disruption of the cross-links induced by UV.

• Research Organization: Harvard Univ., Cambridge, Mass.
• Sponsoring Organization: USDOE
• NSA Number: NSA-16-007441
• OSTI ID: 4819742
• Journal Information: Journal of Cellular and Comparative Physiology, Journal Name: Journal of Cellular and Comparative Physiology Journal Issue: S1 Vol. 58; ISSN 0095-9898
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

AMINO ACIDS
BACTERIA
BIOCHEMISTRY
BIOLOGY AND MEDICINE
DENSITY
DEPOSITS
ENZYMES
LIGHT
MOLECULAR WEIGHT
MOLECULES
NUCLEIC ACIDS
OXYGEN
QUANTITY RATIO
RADIATION DOSES
RADIATION EFFECTS
TEMPERATURE
ULTRAVIOLET RADIATION
VISCOSITY
WEIGHT
YEASTS