Collaboration on Biology of Aging Project

Jim Harper jmharper at
Fri Jul 25 12:55:59 EST 2003

Dear colleagues,

We are looking for collaborators for a simple project on the comparative
biology of aging in rodents.  Below is the rationale behind this study:

Evolutionary theory predicts that species evolving in low hazard niches
should live longer than those evolving in high-risk niches; and indeed
this has been demonstrated repeatedly by comparative biogerontologists.
For example, due to their ability to avoid predation by a variety of
means, squirrels (arboreal), beavers (aquatic), naked mole rats
(fossorial), and porcupines (spiny), have lived more than 10 years in
captivity, while most strains of laboratory mice and rats live to be
only 3-4 years old.  Bats, with their ability to fly, are remarkably
long-lived for mammals of their size, with some species living as long
as 30 years in the wild.  Unfortunately, the specific biochemical and
physiological mechanisms by which this increase in longevity is achieved
remains unknown, although there is a growing body of evidence linking
increased stress resistance with increased longevity in nematodes,
fruitflies, and mice.

In order to test the hypothesis that increased longevity is associated
with an increase in stress resistance across taxa, tissue samples
(abdominal skin, liver, skeletal muscle) will be collected from four
long-lived rodent species: (a) grey squirrels (Sciurus carolinensis),
(b) Southern flying squirrels (Glaucomys volans), (c) North American
porcupines (Erethizon dorsatum), and (d) North American beavers (Castor
canadensis), as well as two species of bats, the big brown bat
(Eptesicus fuscus) and the little brown bat (Myotis lucifugus), and used
to establish cultures of dermal fibroblasts.  Samples taken from
laboratory mice (Mus musculus domesticus) and rats (Rattus norvegicus
domesticus) will act as short-lived ‘controls’.  In brief, these
cultures are subjected to a variety of stressors (e.g., heat, UV
radiation) in order to assess their degree of cellular stress resistance
using a survival assay. The expectation is that the long-lived species
will be more resistant to stress than the short-lived species.
Moreover, with the advent of DNA microarray technology, monitoring
global patterns of gene expression is almost routine, and it will be of
considerable interest to learn whether all long-lived mammals exhibit
similar patterns of gene expression.  This project will also allow us to
address this question by using RNA isolated from the liver and skeletal
muscle samples.

In particular we hope that someone may be able to provide us with tissue
samples collected from known aged individuals of any or all of the
species listed above.  If you think you may be able to help us please
contact me at jmharper at  Thanks!


James M. Harper, Ph.D.
Research Fellow
Dept. of Pathology and Institute of Gerontology
University of Michigan

Phone: 734-936-2164
FAX: 734-936-9220

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