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#cell aging

3 public questions tagged with this topic.

Animal Tissue Culture 3

The senescence phase in cell culture corresponds to:

Senescence phase in cell culture corresponds to death or decline phase of growth curve where proliferative capacity permanently lost and net cell number decreases. Replicative senescence triggered by telomere attrition beyond critical threshold leads to uncapped chromosome ends recognized as DNA double-strand breaks activating ATM and ATR kinases that stabilize p53 and induce cyclin-dependent kinase inhibitors p21CIP1 and p16INK4a causing irreversible G1 arrest. Morphology changes to enlarged flattened cells with increased granularity, vacuolation, positive senescence-associated beta-galactosi

Ref: Hayflick L Exp Cell Res 1961 senescence death phase; Campisi J Cell 2005 Senescence SASP and p16 p53 pathways.

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Animal Tissue Culture 2

The Hayflick limit refers to:

Hayflick limit defines finite number of times normal somatic cells can divide before entering senescence, discovered by Leonard Hayflick and Paul Moorhead in 1961 using human fetal lung fibroblasts WI-38. They observed progressive decline in doubling capability leading to arrest after approximately 40-60 population doublings, refuting earlier claims by Alexis Carrel that cultured cells were immortal. Molecular basis is incomplete replication of linear chromosome ends due to end-replication problem: DNA polymerase cannot fully replicate 3 prime overhang, causing loss of 50-200 base pairs of tel

Ref: Hayflick L Exp Cell Res 1961 finite division; Watson et al Molecular Biology of the Gene 7th Ed Telomere shortening and replicative senescence.

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