longevity in C. elegans 2

Vladimir V. Bakaev vlad at bakaev.nsk.ru
Mon Aug 25 22:38:12 EST 1997


     Dear Dr. Brian Rowley:
     You wrote:
>Stabile homeothermic organisms like humans and house mice show signs of
>metabolic damage if their body temperature is lowered by much, unlike
>poikilothermic or labile homeothermic (e.g., hibernating) organisms who are
>adapted to periods of low temperature (Walford RL, and Spindler SR: The
>response to caloric restriction in mammals shows features also common to
>hibernation: a cross-adaptation hypothesis. J. Gerontol. 52A:B179-183,
>1997). Comment: lowering human body temperature beyond a certain range
>doesn't sound like a promising anti-aging strategy, though the modest
>reduction seen with caloric restriction might confer some longevity benefit.
********************************************************************
>Why were the nematodes kept at 21.3 degrees Celsius in one=20
>group, but only 9.0, 6.3 and 2.0 degrees Celsius in the=20
>others? The temperature difference between groups seems=20
>rather high. Less dramatic lowering of temperature=20
>(e.g., to 16.3 degrees Celsius) might still increase life=20
>span of nematodes, even while freezing in liquid nitrogen=20
>decreases it :-> Secondly, optimal conditions for life span=20
>might not be optimal for species (e.g., species reproduction).

In my previos experiment,  which see partly below, I found, that lowe-
ring of temperature to +4oC increased longevity in _adult_  nematodes.
I  discussed stidy I lowered temperature during _larval_ period of de-
velopment, which not increased longevity. I cannot explain such pheno-
men.

>From The Worm Breeder's Gazette, 1995, v. 14, No. 1, p. 102.
(this appeared as "longevity in C. elegans", too)
     THE EFFECT OF INTERMITTENT TEMPERATURE ON LONGEVITY
               AND FECUNDITY OF C. ELEGANS
********************************************************************
It is well known that low temperatures can prolong  longevity
of  different  animals.  In this study the experimental worms
were mantained in liquid medium with E.  coli in +21oC during
the  day (8 - 12 hrs) and in +4oC during the night,  in dark-
ness.  One control group was mantained  in  +21oC  and  other
control group was mantained in +4oC constantly.  The obtained
results   are   presented    in    the    following    table.
─────────────────────────────────────────────────────────────
            Control group    Experimental   Control group
               (+21oC)          group          (+4oC)
              Mean+/-S.D.     Mean+/-S.D.   Mean+/-S.D.
────────────────────────────────────────────────────────────
Mean longe-  19,86+/-1,63    22,96+/-1,57   38,3+/-2,72
vity (days)     (n = 22)        (n = 24)      (n = 22)
─────────────────────────────────────────────────────────────
Maximal lon-
gevity (days)      34               35            50
────────────────────────────────────────────────────────────
Minimal lon-
gevity (days)       6               10             5
─────────────────────────────────────────────────────────────
Mean         76,91+/-4,54    54,33+/-3,32   4,54+/-2,07
fecundity       (n = 22)         (n = 24)      (n = 22)
─────────────────────────────────────────────────────────────
Maximal           118               95            46
fecundity
─────────────────────────────────────────────────────────────
Minimal
fecundity          33               25             0
─────────────────────────────────────────────────────────────
It can be concluded that such intermittent temperature is not
able to prolong the life-span of C. elegans significantly, in
comparison with constant cold,  as well as fecundity.
********************************************************************
     Sincerely yours, Bakaev V.V.
P.S. I  tried  to  send this message to your e-address,  but
without success.





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