Additional nematode - heat stress

["Thomas J Savin " <tjsav@LYCOS.COM>]

Additional data, note the resistance to HEAT - From Science Vol 295 no.5554 pgs502-505.  January 18, 2002





In summary, we have found that the aging process of C. elegans is modulated, during adulthood, by the activity of germ-line stem cells. How might these cells affect aging? One possibility is that germ-line proliferation shortens life-span by increasing energy expenditure, channeling resources that could otherwise be used for maintaining cellular integrity toward growth and reproduction. However, there does not appear to be a simple trade-off between reproduction (or energy expenditure) and aging in this system; for example, animals that lack the entire reproductive system are not long-lived. Another possibility is that the role of germ-line stem cells is simply to produce more germ-line tissue, which then influences life-span regardless of its state of differentiation. However, the gonads of daz-1 mutants have a much smaller mass than those of glp-1 mutants shifted to high temperature as adults, because oocyte precursors die instead of becoming large, mature oocytes (15). Yet !

d

az-1 animals are not long-lived. Therefore the germ-line stem cells may be uniquely capable of influencing life-span. We propose that stem-cell proliferation influences life-span by affecting either the production of, or the response to, a steroid hormone ligand for DAF-12, which, in turn, promotes longevity. In addition, a signal dependent on stem-cell proliferation must regulate the nuclear localization of DAF-16 in somatic nongonadal tissues (25). 

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Tom Savin





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