Genotoxic Substances

Genotoxic substances (mutagenic) are substances that, after inhalation, ingestion or skin penetration, can cause or increase the frequency of genetic damage. Mutagenic substances cause a change in the genetic code of cells. A mutation is a permanent change in the amount or structure of genetic material in an organism, which results in a change in the characteristics of the organism. Changes can involve a single gene, a block of genes, or an entire chromosome.

Occurrence of genotoxic substances

These are substances that are contained all around us - in the air, soil, water, food and in our home environment. In addition, the mutagenic effect was proven for a number of drugs - antibiotics, cytostatics and disinfectants. They can occur naturally, but are more often the products of human activity.

Schemes of selected structural chromosomal aberrations

Can be detected in food:

• naturally genotoxic substances: flavonoids (quarcetin, rutin) and tannins (their contribution to damage is minimal);
• mycotoxins: (aflatoxin B1 – produced by the fungus Aspergillus flavus , pauline, ochratoxin): products of fungi arising from improper storage of food (cereals, nuts, beans);
• substances of artificial origin:
  • nitrates, nitrites and nitrosamines – in meat, cold meats and cheeses; pyrolyzates of amino acids are created by inappropriate heat treatment of meat;
  • polycyclic aromatic hydrocarbons, polyhalogen hydrocarbons (PCB/TCDD/F), pesticides – DDT, HCH (these substances accumulate in fat tissue);
• metals with a genotoxic effect – arsenic, hexavalent chromium, nickel, cadmium, lead.

The following can be detected in water:

• products for disinfection of drinking water by chlorination (chloroform, dichlorophenols, dichlorobenzene);
• styrene and formaldehyde.

We find a number of substances in the air that are tied to local activity:

• metals and their compounds (arsenic, chromium, nickel, lead, cadmium);
• organic compounds (benzene, formaldehyde).

In the domestic environment, substances are released from building elements, furniture and textiles:

• formaldehyde, styrene, acrylates, phthalates, vinyl chloride.

Types of mutations and their health significance

• Gene (point) mutations – arise by changing the sequence of nucleotides in the DNA molecule. They affect individual genes, are transmitted to subsequent generations of cells and offspring, and represent a serious burden on the gene pool of the population. Gene mutations are not detectable under an optical microscope.
  • congenital metabolic disorders (phenylketonuria, galactosemia)
  • chondrodystrophy, hemophilia
• Chromosome (chromosome aberrations) – are changes in the structure of chromosomes. The condition is a chromosome break followed by a faulty connection or the loss of a part of the chromosome. They are usually not passed on to the next generation. They pose a serious risk to the affected individual. They are detectable in an optical microscope.
  • oncogene activation at the break point
  • degenerative disease (atherosclerosis)
  • accelerated aging of cells and tissues
• Genomic (aberration of the number of chromosomes) – this is a change in whole multiples of the haploid number of chromosomes (triploidy, tetraploidy, polyploidy). They are detectable in an optical microscope.
  • Down syndrome, Turner syndrome, Klinefelter syndrome

Primary prevention of late effects of chemical substances

1. genotoxic activity testing – new genotoxic substances are prevented from entering the environment
2. environmental monitoring - detection of genotoxic substances in the environment (chemical methods, Ames test)
3. exposure monitoring – detection of genotoxic substances and their metabolites in the human body
4. monitoring of the biological effect - monitoring the reaction of the organism to the action of genotoxically active substances (genetic toxicology, immunological, biochemical methods)
5. monitoring the occurrence of genetically determined defects

Links

Related articles

• Toxicogenetics

References

• BENCKO, Vladimír, et al. Hygiene : Textbooks for seminars and practical exercises. 2. revised and supplemented edition edition. Prague : Karolinum, 2002. 205 pp. pp. 18-31. ISBN 80-7184-551-5 .

• Czech republic. Ministry of Industry and Trade. Current chemical legislation. 2008. Available from <https://www.mpo.cz/dokument27543.html>.