In order to minimize exposure to mutagens, the majority of developed countries have instituted regulatory protocols governing the introduction of new foods and food-associated chemicals before they are accepted into the marketplace. Foods also contain many compounds that can modulate the activity of mutagens. Mutagenic compounds can also be produced during food cooking and preparation. However, additional foodborne mutagens can be present as residues of compounds used during food production or leached from packaging materials. Many natural constituents of food are mutagenic and are produced by plants as defense agents. In addition to these sources, significant exposure to mutagenic compounds can occur through food and water, as well as through environmental and occupational sources. The spontaneous hydrolysis of DNA bases from the sugar–phosphate backbone, constant exposure of cellular DNA to oxygen-derived free radicals and low rates of miscopying during DNA replication all contribute towards the mutational burden. Genetic predispositions to certain breast and colon cancers, cystic fibrosis, and Huntington's disease are included among many examples of such inheritable diseases.Īlthough many dietary and environmental agents have been classified as mutagens, cells are constantly subjected to a barrage of spontaneous DNA damage. While the health of a particular individual can be affected by mutations in somatic cells, mutagenic events in germ cells ( germline mutations) lead to the transmission of genetic diseases to subsequent generations. In addition, the accumulation of mutations over time, leading to gradually less efficient cellular repair capabilities, has been linked to the aging process and associated degenerative diseases. For example, mutations in genes that promote or inhibit growth and cellular replication ( protooncogenes and tumor suppressor genes, respectively) or code for components of DNA repair pathways are important contributors to the multistage development of cancer. The influence of mutations in human health is underscored by several human disease states caused by mutations that disrupt regulatory regions or gene coding sequences, resulting in altered gene expression and protein function. Thus, a mutagenic event occurring in a nonfunctional area of DNA will have no effect ( silent mutation), whereas a similar change in an actively transcribed region may profoundly affect gene expression and phenotype or even lead to cell death ( lethal mutation). The biological consequences of a mutation depend upon many critical factors such as the target loci, size of the mutation, timing during the cell cycle, and compounding effects of preexisting mutations. In this way, mutagenesis becomes a cumulative process, stretching over the lifetime of an organism. Upon subsequent cellular replication, these mutations become fixed in the genome and are inherited by all daughter cells. Mutagenic lesions persist when they escape detection by protective cellular DNA repair mechanisms, when mistakes occur in the repair process, or when repair mechanisms are overwhelmed by extensive damage. Mutagens are chemical compounds or forms of radiation (such as ultraviolet (UV) light or X-rays) that cause irreversible and heritable changes (mutations) in the cellular genetic material, deoxyribonucleic acid (DNA). Schrader, in Encyclopedia of Food Sciences and Nutrition (Second Edition), 2003 Background The possibilities for dietary prevention and modification of mutagen formation are then followed by a discussion of current and future avenues for further research. Mutagens have also been identified in drinking water and in the feces after digestion. Various food-associated mutagens are presented, classified as natural constituents compounds arising during processing, preparation, or storage and those found as food additives and contaminants. Bacterial and mammalian assays for mutagen detection and characterization are described, followed by a discussion of developments in quantitative structure–activity relationship modeling. Mutagens are identified as genotoxic carcinogens, and various classes of mutation are defined, including extragenic, gene, chromosomal, and genomic mutations. Various forms of DNA damage leading to mutations are outlined, as is the activation of some mutagens through metabolic processes. Schrader, in Encyclopedia of Food and Health, 2016 AbstractĪ mutagen is defined as an agent that causes irreversible and heritable changes (mutations) in the cellular genetic material, deoxyribonucleic acid (DNA).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |