longevity in C. elegans 2

Vladimir V. Bakaev vlad at bakaev.nsk.ru
Sun Aug 24 04:00:02 EST 1997


>From The Worm Breeder's Gazette, 1995, v. 14, No. 1, p. 103.

THE EFFECT OF LOW TEMPERATURES DURING EARLY DEVELOPMENT
ON LONGEVITY AND FECUNDITY IN THE NEMATODE C. elegans
 Vladimir V. Bakaev, box 45, Novosibirsk, 630107, USSR

The purpose of the present experiment is to investigate,
how low temperatures in the early stages of development
can influence fecundity, length of prereproductive peri-
od, length of reproductive period, length of postrepro-
ductive period and mean life span in the nematode C. ele-
gans (Bristol, N2, wild type). To microtitre wells were
added 0,75 ml of liquid medium with E. coli (OP 50) and
3 adult nematodes. Animals were kept during 12 hours in
the room temperature, then adult nematodes were discarded
and wells were stored in different temperatures during 2
days, then they were transferred in room temperature. New-
ly appeared worms were  transferred in next wells, every
well contains a single nematode. In every following day
these worms were transferred in next wells. All the ex-
periments were done in the darkness. Results are given in
mean+/-S.E.
─────────────────────────────────────────────────────────────
Tempe- Number            Length of                 Mean
rature   of      ──────────────────────────────    life
 оC    progeny    prerepro- reproduc- postrep-     span
                  ductive   tive      roductive    days     n
                  period    period    period
                  days      days      days
─────────────────────────────────────────────────────────────
21,3  79,8+/-5,4  2,2+/-0,1 8,3+/-0,4 12,8+/-1,1 24,4+/-1,1 26
 9,0  77,0+/-5,5  3,3+/-0,1 7,7+/-0,6 11,1+/-1,3 22,8+/-1,5 25
 6,3  67,8+/-3,4  3,8+/-0,1 7,0+/-0,4 11,7+/-1,5 23,2+/-1,5 23
 2,0  68,5+/-5,0  4,3+/-0,2 7,1+/-0,4  8,6+/-1,2 21,1+/-1,1 20
─────────────────────────────────────────────────────────────
Then, lowering of ambient temperatures during early deve-
lopment of nematode C. elegans resulted in decreasing of
progeny. There is a decrease in the mean life span as tem-
perature during larval development decreased, as well as
the length of reproductive and the length of postreproduc-
tive periods. Then, the length of prereproductive period
is increased by diminishing of the temperature of early
development. These results demonstrate, that the higher is
the temperature, the earlier nematodes started reproduc-
tion. These results do not support the widely accepted point
of view, that lowering of temperature increases life span
of different animals. There exist optimal life conditions
for species, in which life span of this species is maximal.
But the problem arises: what must we do in order to obtain
the marked increase of longevity and, probably, immortali-
ty? Undoubtedly, it appeared reasonable to seek a new un-
usual experimental approaches.
Acknowledgment: The author wishes to express his thanks to
CGC for providing C. elegans and E. coli.





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