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Re: Peter Parsons in Biogerontology
on 10/3/02 10:21 AM, Jacobus, John (NIH/OD/ORS) at jacobusj@ors.od.nih.gov
wrote:
> Jim,
> I guess this goes back to the old joke about the need to pick your parents
> to get the best genes.
>
> I notice they do not identify radiation has a useful stressor to increase
> lifespan.
Funny. In English it says exactly that! But then you never read anything.
> -- John
> John Jacobus, MS
> Certified Health Physicist
> 3050 Traymore Lane
> Bowie, MD 20715-2024
>
> E-mail: jenday1@email.msn.com (H)
>
> -----Original Message-----
> From: Muckerheide [mailto:muckerheide@attbi.com]
> Sent: Tuesday, October 01, 2002 7:27 AM
> To: radsafe@list.vanderbilt.edu
> Subject: Peter Parsons in Biogerontology
>
>
> Friends,
>
> Our friend Peter Parsons has published the following paper.
>
> Regards, Jim Muckerheide
> Radiation, Science, and Health
> ===============================
>
> Biogerontology 2002;3(4):233-41
>
> Life span: does the limit to survival depend upon metabolic efficiency
> under stress?
>
> Parsons PA.
> La Trobe University, Bundoora, Vic. 3083, Australia; Author for
> correspondence: P.O. Box 906, Unley, SA 5061, Australia (e-mail:
> pparsons@senet.com.au; fax: +61-8-8373-5557)
>
> Survival to old age in natural populations is enhanced by high vitality
> and resilience which depends upon substantial homeostasis and energetic
> and metabolic efficiency underlain by genes for stress resistance. Under
> this assumption increased longevity follows from primary selection for
> stress resistance where stress targets energy carriers. Furthermore old
> and young fitness should be correlated irrespective of age under the
> stressful selection regime of natural populations. In contrast,
> antagonistic pleiotropy is most likely under the less rigorous selection
> regime of well-nourished humans and laboratory populations surviving to
> old age. Similarly, hormesis for longevity, for example from a mild
> temperature stress or restricted food intake is most likely under benign
> environmental conditions. Assuming that aging in natural populations
> depends upon ecological circumstances, large evolutionary increases in
> life span are unlikely under the stress theory of aging since organisms
> are frequently close to their limits of survival where metabolic
> efficiency is at a premium. Exceptions can occur in island populations
> and for mutants under laboratory conditions since the risks from
> environmental hazards are reduced, and life span becomes extended as a
> consequence. In modern human populations, selection for stress
> resistance is less intense than in earlier times which should be
> permissive of the accumulation of stress-sensitive mutants under the
> mutation-accumulation theory of aging. However, this process is
> ultimately likely to restrict the evolution of life-span extensions in
> the future especially if abiotic conditions deteriorate, when survival
> would depend more directly on metabolic efficiency under stress.
>
> http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list
> _uids=12232505&dopt=Abstract
>
>
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