Is nitrous acid a chemical mutagen?
Nitrous acid is a mutagenic agent that exhibits two types of chemical reactions with DNA: firstly it converts exocyclic amino groups of DNA heterocycles to carbonyl groups (1,2) and secondly it produces interstrand cross-links in duplex DNA (3,4).
What kind of mutations does nitrous acid cause?
Nitrous acid (NA) is often presumed to cause base substitutions in organisms with double-stranded DNA as a direct consequence of oxidative deamination of adenine and of cytosine residues. Here we summarize evidence indicating that other mechanisms are involved in the case of NA-induced G/C–>A/T transition mutations.
What are some examples of chemical mutagens?
Most chemical mutagens are alkylating agents and azides. Physical mutagens include electromagnetic radiation, such as gamma rays, X rays, and UV light, and particle radiation, such as fast and thermal neutrons, beta and alpha particles.
What are common chemical mutagens?
The most commonly used chemical mutagens are alkylating agents such as ethylmethane sulfonate and N-methyl-N-nitrosourea that induce point mutations in DNA.
How is nitrous acid causing mutations in DNA?
Nitrous acid, a potent chemical mutagen, exerts its effect by the deamination of the aminogroups of the adenine, cytosine and guanine residues of the nucleic acid (causing chemical alterations A—»HX, G—»X, C—>U) as well as cross-links of undefined structures, deletions (Schuster, 1960; Kotaka and Baldwin, 1964; …
Is nitrous acid carcinogenic?
The nitrous acid usually arises from protonation of a nitrite. This synthesis method is relevant to the generation of nitrosamines under some biological conditions. Nitrosamines are not directly carcinogenic.
What is the difference between chemical and physical mutagens?
The two main types of mutagens are physical and chemical. A physical mutagen is in the form of a physical substance. A chemical mutagen is a mutating agent in the form of a chemical substance. These substances work by mimicking nitrogenous bases in genetic material that cannot be duplicated during DNA replication.
What are some physical and chemical agents that cause mutations?
The chemical or physical agents that cause mutations are called mutagens. Examples of physical mutagens are ultraviolet (UV) and gamma radiation. Radiation exerts its mutagenic effect either directly or by creating free radicals that in turn have mutagenic effects.
What is mutagen discuss any two classes of chemical mutagen?
are the common mutagens. Three different types of common mutagens are observed in nature- physical and chemical mutagens agents and biological agents. Radiations are the primary mutagenic agent reported in 1920. UV rays, X-rays, alpha rays, neutrons, and other ionizing and non-ionizing radiations are mutagenic.
What is methylated cytosine?
Cytosine methylation is a common form of post-replicative DNA modification seen in both bacteria and eukaryotes. Modified cytosines have long been known to act as hotspots for mutations due to the high rate of spontaneous deamination of this base to thymine, resulting in a G/T mismatch.