On the immortality of the germ line: Genetic and biochemical mechanisms. A review

Medvedev, Zhores A.

doi:10.1016/0047-6374(81)90052-x

Cited by 63 publications

(20 citation statements)

References 98 publications

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“…40,[55][56][57] Attempts to explain the obvious fact that newborn animals are undamaged by the aging process despite their originating from adult germ cells (which potentially may accumulate certain senescent changes) involved the concept of periodical rejuvenation of the germ cell lines being necessary to provide immortality in generations. 56,58 It was assumed that meiosis is a key event in the rejuvenation of germ cells. [55][56][57] However, this assumption seems to be completely disproved by recent advances in animal cloning.…”

Section: Rejuvenation Through Growth and Cell Divisionmentioning

confidence: 99%

Garbage catastrophe theory of aging: imperfect removal of oxidative damage?

Terman

2001

Redox Report

141

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Increasing evidence suggests an important role of oxidant-induced damage in the progress of senescent changes, providing support for the free radical theory of aging proposed by Harman in 1956. However, considering that biological organisms continuously renew their structures, it is not clear why oxidative damage should accumulate with age. No strong evidence has been provided in favor of the concept of aging as an accumulation of synthetic errors (e.g. Orgel's 'error-catastrophe' theory and the somatic mutation theory). Rather, we believe that the process of aging may derive from imperfect clearance of oxidatively damaged, relatively indigestible material, the accumulation of which further hinders cellular catabolic and anabolic functions. From this perspective, it might be predicted that: (i) suppression of oxidative damage would enhance longevity; (ii) accumulation of incompletely digested material (e.g. lipofuscin pigment) would interfere with cellular functions and increase probability of death; (iii) rejuvenation during reproduction is mainly provided by dilution of undigested material associated with intensive growth of the developing organism; and (iv) age-related damage starts to accumulate substantially when development is complete, and mainly affects postmitotic, cells and extracellular matrix, not proliferating cells. There is abundant support for all these predictions.

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Section: Rejuvenation Through Growth and Cell Divisionmentioning

confidence: 99%

Garbage catastrophe theory of aging: imperfect removal of oxidative damage?

Terman

2001

Redox Report

141

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“…Consequently, it has been argued that the germline, or at least the gametes, must be protected from damage but it is not clear how or whether this is indeed the case. Nevertheless, different principal means of protecting the germline has been hypothesized, including germ cells enjoying elevated, or more functional, homeostatic maintenance systems (Hernebring et al, 2006), an asymmetrical partitioning of damage during gametogenesis, and ⁄ or a selection process that rids the organisms of germ cells exhibiting high levels of damage (Medvedev, 1981). In conjunction with such ideas, it has been stressed that there are 'trade-offs' between reproductive success and somatic maintenance (Williams, 1957;Kirkwood, 1977;Barnes & Partridge, 2003).…”

Section: Introductionmentioning

confidence: 98%

Effects of aging and reproduction on protein quality control in soma and gametes of Drosophila melanogaster

et al. 2012

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SummaryIn organisms with a soma-germ demarcation, the germline must be 'preserved' such that harmful damage is not transmitted to the offspring. Keeping the progeny free of damage may be achieved by gametes enjoying elevated, and ⁄ or more functional, homeostatic maintenance systems. This possibility was approached here by testing whether the soma and maturating oocytes (eggs) dissected from female Drosophila melanogaster in reproductive ages display differential capacities for protein quality control and whether these capacities change during aging and mating. Eggs exhibited a high capacity to prevent protein aggregation, strong capacity for 26S proteasome-dependent degradation and reduced levels of oxidatively damaged (carbonylated) proteins compared to the soma. The capacity to prevent protein aggregation was not affected in either soma or eggs by age and ⁄ or mating, while the 26S proteasome capacity declined in the soma but was maintained in the eggs of aged females. However, the levels of carbonylated proteins increased with age in both soma and eggs, and this increase was more pronounced in females allowed to mate continuously. Furthermore, the levels of carbonylated proteins in the eggs of mated flies correlated negatively with the propensity of the eggs to develop into an adult fly. In young flies, mating caused a decrease in 26S proteasome capacity and an increase in protein carbonylation in the soma, but not in the eggs. These results are in line with trade-off theories of aging where aging is considered a consequence of investment in reproduction over somatic maintenance.

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“…The nature of the germ line and its relevance to hereditary stability (yet within evolutionary variation) suggests that special strategies may exist for the maintenance of its DNA, and much has been written about the possible rejuvenating and correcting properties of recombination, meiosis and gametogenesis (see Martin, 1977;Medvedev, 1981;Bernstein et al 1984). However, the DNA at meiosis undergoes additional manipulations and this may carry specific risks.…”

Section: Dna Maintenance In the Germ Linementioning

confidence: 99%

“…Medvedev (1981) emphasized the oppor tunities for selection at the haploid stage of gametogenesis. Such opportunities, however, do not seem to apply to the human situation.…”

Section: Dna Maintenance In the Germ Linementioning

confidence: 99%

DNA Maintenance and its Relation to Human Pathology

Giannelli

1986

Journal of Cell Science

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On the immortality of the germ line: Genetic and biochemical mechanisms. A review

Cited by 63 publications

References 98 publications

Garbage catastrophe theory of aging: imperfect removal of oxidative damage?

Garbage catastrophe theory of aging: imperfect removal of oxidative damage?

Effects of aging and reproduction on protein quality control in soma and gametes of Drosophila melanogaster

DNA Maintenance and its Relation to Human Pathology

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