X-Message-Number: 26293
Date: Mon, 6 Jun 2005 22:28:44 -0700 (PDT)
From: Doug Skrecky <>
Subject: more about immortal fungi

     The grisea mutant is beleived to live longer than wild type podospora
 anserina because of decreased mitochondrial generation of free radicals.
 Restricting copper availability also reduces mitochondrial free radical
 production, so it comes as litle surprise that this intervention boosts
 wild type lifespan. Copper chelation has an even more radical effect on
 grisea, with 80% survival being increased from 40 to 120 days. Maximum
 lifespan under this condition is unknown.
     Why is the ex1 mutant immortal? Ex1 has higher cystolic copper levels
 so it would seem unlikely that free radicals were reduced in this
 compartment. On the other hand, the generation of free radicals within
 ex1 mitochondria are believed to be even lower than for grisea. Is this
 why the ex1 mutant is immortal? Nobody knows for sure.
     Even if mitochondrial free radicals are the critical factor in fungi,
 there exists no proof that this is important in mammalian aging.
 Mitochondrial mutant rodents have been produced that suffer from
 increased free radical generation, but these animals age normally. Is
 there a threshold above which free radicals can no longer modulate aging?
 Again nobody knows for sure.

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