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Publication
SenescĂȘncia em bactĂ©rias
| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| PPG_18960 | 1.79 MB | Adobe PDF |
Advisor(s)
Abstract(s)
A senescĂȘncia apresenta-se como um processo metabolicamente ativo, desencadeado por mĂșltiplos fatores, limitando o tempo de vida, uma vez que quando a cĂ©lula entra em processo de senescĂȘncia perde irreversivelmente a capacidade de proliferar. As bactĂ©rias eram consideradas microrganismos potencialmente imortais devido Ă sua reprodução assexuada por fissĂŁo binĂĄria. Contudo, estudo realizados quer com bactĂ©rias que sofrem divisĂŁo assimĂ©trica (Caulobacter crescentus), quer com bactĂ©rias onde a divisĂŁo Ă© aparentemente simĂ©trica (Escherichia coli), demonstram que os seus constituintes celulares nĂŁo sĂŁo aleatoriamente distribuĂdos pelas duas cĂ©lulas-filha, havendo uma segregação assimĂ©trica de danos celulares e fatores de envelhecimento. A anĂĄlise dos mecanismos moleculares subjacentes Ă degeneração celular bacteriana revela semelhanças interessantes com o processo de envelhecimento de organismos superiores.
Senescence presents itself as a metabolically active process, triggered by multiple factors, limiting the life time, since when the cell enters in senescence, it looses irreversibly the capacity to proliferate. Bacteria were considered potentially immortal organisms due to their asexual reproduction by binary fission. However, studies using either bacteria with asymmetric fission (Caulobacter crescentus), either bacteria where the division is apparently symmetric (Escherichia call), showed that their cellular constituents are not randomly distributed between the two daughter cells, and that there is an asymmetric segregation of cell damage and aging factors. The analysis of the molecular mechanisms underlying bacterial cell degeneration reveals interesting similarities with the aging process of higher organisms.
Senescence presents itself as a metabolically active process, triggered by multiple factors, limiting the life time, since when the cell enters in senescence, it looses irreversibly the capacity to proliferate. Bacteria were considered potentially immortal organisms due to their asexual reproduction by binary fission. However, studies using either bacteria with asymmetric fission (Caulobacter crescentus), either bacteria where the division is apparently symmetric (Escherichia call), showed that their cellular constituents are not randomly distributed between the two daughter cells, and that there is an asymmetric segregation of cell damage and aging factors. The analysis of the molecular mechanisms underlying bacterial cell degeneration reveals interesting similarities with the aging process of higher organisms.
Description
Keywords
SenescĂȘncia DivisĂŁo celular assimĂ©trica DivisĂŁo celular simĂ©trica Procariontes EspĂ©cies reativas de oxigĂ©nio SenescĂȘncia replicativa SenescĂȘncia condicional Senescence Asymmetric cell division Symmetric cell division Prokaryotes Replicative senescence Conditional senescence