[Killietalk] Killifish can survive without oxygen for 60 days

[David Howser <dlhowser at yahoo_com>]

Killifish can survive without oxygen for 60 days
27 June 2007 
NewScientist.com news service 
 
Tools
  How long can you hold your breath? For even highly
trained humans, it's a few minutes, tops. Compare that
with the killifish, which can survive without oxygen
for more than 60 days, by far the longest of any
vertebrate.

Annual killifish, Austrofundulus limnaeus, live in
temporary ponds in arid regions of Venezuela. Their
embryos ride out seasonal droughts buried in mud,
where microbial action often uses up all the oxygen.

Jason Podrabsky, a comparative physiologist at
Portland State University in Oregon, and his
colleagues tested killifish embryos by sealing them in
oxygen-free vials. After 62 days, half the embryos
recovered when given oxygen (The Journal of
Experimental Biology, vol 210, p 2253). The next best
vertebrates - turtles and a species of goldfish - can
survive for only a few days.

Podrabsky found that longer-lived killifish embryos
accumulated lactate - the end product of anaerobic
metabolism - very slowly, suggesting that their
anaerobic ability comes from being able to cut their
metabolic rate to extremely low levels.

Podrabsky is now studying which genes are responsible
for the metabolic slowing. Learning how the fish do
this may help explain how human tissues respond to
anoxia during, say, a heart attack, Podrabsky says.

>From issue 2609 of New Scientist magazine, 27 June
2007, page 15

http://www.newscientist.com/article/mg19426095.400-killifish-can-survive-without-oxygen-for-60-days.html



       
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