Norman E. Andrews [ MT 2C-402 9089575786 NC6241000 ] (norm at chico.uucp) wrote:
: I thought the Hayflick Limit turned out to be spurious, that it was due
: to improper culture techniques (poor nutrition or contamination). Anyone
: know about this?
: Norm Andrews, AT&T, norm at chico.wh.att.comNo, the hayflick limit is NOT due to culture techniques. The best
experimental evidence for this statement is the well established
observation that when the same cell types, from different species are
grown under identical conditions with the identical solutions in the
same incubator, quite different Hayflick limits are observed. The
observation is quite good evidence that the Hayflick limit is due to the
cells and not to the medium. The second line of evidence is the
existence of human genetic disorders like Werner's syndrome, which is a
premature ageing disease, in which the identical cells to a normal
control, in the same mediium in the same incubator, do in fact grow as
much as 1000 times less than the control cells. This again makes it
clear that the hayflick limit is due the cells and not the medium.
Finally, one can grow normal cells and observe an Hayflick limit and
tumour cells and not observe any limit; in the same medium and
incubator. In general therefore, the hayflick limit is a biological
phenomenon, and not a culture artifact.
This evidence given above does not prove that the culture conditions are
totally irrelevant to the way normal cells grow in culture; the culture
conditions very clearly do modulate the growth rate and the Hayflick
limit, but only within narrow boundaries.
--
Sydney SHALL,
Laboratory of Cell and Molecular Biology,
Biology Building, University of Sussex, Brighton, East Sussex BN1 9QG, ENGLAND.
Telephone: +44.273.67.83.03 FAX: +44.273.67.84.33
