Failure Disaster Theory
The error catastrophe theory, also known as error catastrophe (of aging) , is a theory put forward in 1963 by the British chemist Leslie Orgel to explain the causes of aging. The theory is one of the harm theories that are supposed to explain biological aging.
description
The failure-catastrophe theory explains cellular aging by an accumulation of defective enzymes as a result of an inaccuracy in protein synthesis . Errors in protein biosynthesis lead to the formation of inaccurate DNA polymerases , which lead to an increasing number of errors in the amino acid sequence of the proteins in a cell.
The relevance of this theory is based on the importance of DNA for every biological species. In every cell cycle , the cell is divided. To do this, it is necessary after this division of the cell, in which the DNA is also divided, to double it again. When the DNA is doubled, the enzyme first copies the DNA in the so-called mRNA . These specific mRNA molecules contain instructions for the synthesis of individual proteins into a specific amino acid sequence.
The error-catastrophe theory states that small errors in this arrangement of the amino acids due to copying errors during protein synthesis (either during DNA replication or the formation of mRNA) lead to faulty DNA copies. As a result, there will be a chain of these errors at some point, which ultimately lead to cell death. This process is not important for young people as there is little error rate. However, with increasing age, the accumulation of errors increases exponentially. Therefore, this theory explains aging with the increasing probability of errors in protein synthesis and DNA replication, as a chain of several small errors leading to a catastrophe, cell death.
tries
The most famous experiment in connection with the failure-catastrophe theory was carried out with the species of Drosophila . In the first experiments in 1967, under the direction of Harrison / Holliday, a decrease in longevity was found in Drosophila. This test result would therefore support Leslie Orgel's failure catastrophe theory. For the series of experiments carried out, larvae of Drosophila melanogaster , a subgenus of Drosophila, were fed with five different amino acid analogues . The further development of the larvae until death was then observed.
The experiments were carried out exclusively with male specimens of Drosophila melanogaster. The larvae examined were kept in dark boxes and only experienced daylight during the feeding times. Such living conditions are necessary in order to shield possible environmental conditions from the objects being examined. In the actual experiment, a test group was then transferred to prepared boxes containing food with the said amino acid analogues. The larvae were in these boxes for a period of 72 hours. The subsequently surviving population was further observed in unprepared boxes. A control group of Drosophila melanogaster was also kept in unprepared boxes during the experiment.
Further attempts in 1969 with another subspecies of the fruit fly, the Drosophila subobscura, came to the opposite result: a decrease in longevity was not observed. In contrast to the first attempt with Drosophila melanogaster, the young Drosophila subobscura were fed only one amino acid analogue. Since no decrease in longevity was observed in the test carried out, the test results are seen as contradicting Leslie Orgel's failure catastrophe theory.
Unfortunately, there is no more detailed information about this experimental setup by Dingley / Maynard Smith with Drosophila subobscura.
criticism
The originally popular theory has since been discarded due to a lack of experimental evidence. Elements of the theory, however, are still being explored as possible factors in aging. The theory has been criticized because research has now established that DNA polymerases have the ability to recognize incorrect amino acid sequences and to correct or replace them. There are also various repair systems in place to prevent errors in the DNA replication process. There is also insufficient evidence of age-related changes in protein synthesis. What has been proven, however, is that the structure of its proteins changes with increasing age. So far, however, the role of damaged proteins and the associated processes as factors in aging has not yet been researched.
Individual evidence
- ↑ pnas.org
- ^ B. Godde, C. Voelcker-Rehage, B. Olk: Introduction to Gerontopsychology. Ernst Reinhardt Verlag, Munich / Basel 2016.
- ↑ W. Kraft (Ed.): Geriatrics in dogs and cats. Parey Verlag, Stuttgart 2003.
- ↑ pnas.org
- ↑ Ann-Kristin Kollas and others: Why living things age: Theories and models from biology and medicine. Logos Verlag, Berlin 2002.
- ↑ medicine.jrank.org
- ↑ AN Bozcuk: Testing the protein error hypothesis of aging in Drosophila . Pergamon Press, Great Britain 1976.
- ^ Longevity-science.org