Biomaterial Database

Alterations in thermal stability of rat liver chromatin and DNA induced in vivo by dimethylnitrosamine and diethylnitrosamine. 1978

B W Stewart, and E Farber

A study was made of the effects of administration to rats of dimethylnitrosamine and diethylnitrosamine on the transition temperature (Tm) of sheared chromatin and DNA isolated from the liver. The analysis was made by thermal chromatography on hydroxylapatite with the use of DNA prelabeled with [3H]thymidine and following the elution pattern during the operation of a continuous temperature gradient. With a nonnecrogenic dose of dimethylnitrosamine (10 mg/kg), the alterations in chromatin were maximal at 24 hr and disappeared by 3 days. Greatest differences in elution profiles of chromatin after dimethylnitrosamine treatment were observed in the region above 80 degrees. Administration of the carcinogen caused a lowering of the "melting" curve in this region, the displacement from control position being proportional to the dose. The maximum dose (60 mg/kg) displaced the complete chromatin melting curve up to 5 degrees to the lower side. DNA isolated from this chromatin melted 3 degrees less than that from control rats. However, administration of lower doses of dimethylnitrosamine did not affect the melting profile of DNA. The administration of diethylnitrosamine caused a similar type of change. However, the modification was also seen at 50-60 degrees.

UI	MeSH Term	Description	Entries
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008297	Male		Males
D009602	Nitrosamines	A class of compounds that contain a -NH2 and a -NO radical. Many members of this group have carcinogenic and mutagenic properties.	Nitrosamine
D009691	Nucleic Acid Denaturation	Disruption of the secondary structure of nucleic acids by heat, extreme pH or chemical treatment. Double strand DNA is "melted" by dissociation of the non-covalent hydrogen bonds and hydrophobic interactions. Denatured DNA appears to be a single-stranded flexible structure. The effects of denaturation on RNA are similar though less pronounced and largely reversible.	DNA Denaturation,DNA Melting,RNA Denaturation,Acid Denaturation, Nucleic,Denaturation, DNA,Denaturation, Nucleic Acid,Denaturation, RNA,Nucleic Acid Denaturations
D002843	Chromatin	The material of CHROMOSOMES. It is a complex of DNA; HISTONES; and nonhistone proteins (CHROMOSOMAL PROTEINS, NON-HISTONE) found within the nucleus of a cell.	Chromatins
D002845	Chromatography	Techniques used to separate mixtures of substances based on differences in the relative affinities of the substances for mobile and stationary phases. A mobile phase (fluid or gas) passes through a column containing a stationary phase of porous solid or liquid coated on a solid support. Usage is both analytical for small amounts and preparative for bulk amounts.	Chromatographies
D004052	Diethylnitrosamine	A nitrosamine derivative with alkylating, carcinogenic, and mutagenic properties.	Nitrosodiethylamine,N-Nitrosodiethylamine,N Nitrosodiethylamine
D004128	Dimethylnitrosamine	A nitrosamine derivative with alkylating, carcinogenic, and mutagenic properties. It causes serious liver damage and is a hepatocarcinogen in rodents.	Nitrosodimethylamine,N-Nitrosodimethylamine,NDMA Nitrosodimethylamine,N Nitrosodimethylamine,Nitrosodimethylamine, NDMA
D004247	DNA	A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).	DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot