Chemical mutagens are chemical agents that are able to increase the rate of gene mutations and chromosomes. They can often be carcinogenic and teratogenic, that is, they can cause cancer or abnormalities. All of our organ systems are exposed to chemicals. Every day, our body is exposed to various additives, preservatives, nitrates and nitrites, artificial sweeteners found in our food. United metals, various chemicals that we use in agriculture, cosmetics, pharmaceuticals, medicines, even clothing, contain chemicals that are mutagenic.
Rarely can chemicals act directly on genetic material. Most chemicals act indirectly - it is through metabolism that cells become active mutagens. Chemical mutagens can be incorporated into DNA strands instead of nucleotides, between nucleotides, or they can chemically alter them. Thus causing various mutations. Mutagens can also activate carcinogens - substances that can cause cancer. In addition to mutagenic and carcinogenic effects, chemicals can cause developmental disorders - teratogenic effect.
Some drugs during development can cause limb disorders in humans and others primates. Acrolein has teratogenic and mutagenic effects. Cytostatics have mutagenic effects, but are used in cancer therapy, in people who may benefit enough to justfy the harm done.
Chemical mutagens include:
strong oxidants or reducing agents (for example nitrates, nitrites, reactive oxygen species)
alkylating agents (eg iodoacetamide)
pesticides
insecticides (DDT insecticide)
herbicides
fungicides
bactericides
petroleum products
chemical additives to food and beverages (preservatives, additives, sweeteners, etc.)
Chemical mutagens act on the DNA molecule in different ways. They can change the chemical nature of the nitrogenous bases in DNA, so that during the replication there is a missmatch e.g. guanine can be altered so that it does not pair with cytosine but with thymine. In the next round of replication, what was a GC pair before will now be replaced by an AT base pair. Chemical mutagens can also lead to duplications and deletions, changing the reading framework of the genetic code for a certain people protein.
Chemical mutagens act in three ways:
React with DNA and transform bases
They work only during replication, e.g. base analogs such as 5- (bromo-uracil), which is included in DNA molecules instead of the usual bases
The third type of chemical mutagens are acridine dyes. They can be inserted into a DNA molecule and cause insertions or deletions.
In genetic research, purines and analogs are most often used as chemical mutagens, followed by pyrimidine bases, nitric acid, hydroxylamine (NH2OH), alkylating agents and acridines. Of all the chemical mutagens, nitric acid (NHO2) is the most important. It is a very strong mutagen as it acts directly on DNA, that is, it transforms bases from the amino form to the keto form.
Pesticides
Pesticides are chemicals used to control the causes of fungal diseases (fungicides e.g. captan), bacteria (bactericides), harmful insects (insecticides eg DDT insecticide, lindane and sevin), rodents (rodents) and weeds (berbicides). Many pesticides are also harmful to the human body.
Food supplements
Food additives such as caffeine, cyclamate, sodium nitrite and sodium bisulfite are mutagenic. It is considered that caffeine and related purines (for example theobromine) are mutagenic in such a way that they prevent DNA polymerase enzymes, enableing the regeneration (union) of broken chromosomes. Caffeine is obtained from the seeds of coffee, cola, cocoa, paulinia and tea leaves.
Drugs and antibiotics
Many drugs can contain toxic, mutagenic, carcinogenic and teratogenic substances. Sulfanilamides, thiazine products, nitrofurans, sedatives (librium, meprobamate) and drugs (marijuana, LSD) act mutagenically. The antibiotics chloramphenicol and cyclohexamide inhibit protein synthesis and cause chromosomal mutations. The antibiotic streptomycin is mutagenic and patulin is carcinogenic.
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