such as "Introduction", "Conclusion"..etc
Scientists have identified a novel antifreeze molecule in a
freeze-tolerant Alaska beetle able to survive temperatures below minus
100 degrees Fahrenheit. Unlike all previously described biological
antifreezes that contain protein, this new molecule, called xylomannan,
has little or no protein. It is composed of a sugar and a fatty acid and
may exist in new places within the cells of organisms.
"The most exciting part of this discovery is that this molecule is a
whole new kind of antifreeze that may work in a different location of
the cell and in a different way," said zoophysiologist Brian Barnes,
director of the University of Alaska Fairbanks Institute of Arctic
Biology and one of five scientists who participated in the Alaska Upis
ceramboides beetle project.
Just as ice crystals form over ice cream left too long in a freezer,
ice crystals in an insect or other organism can draw so much water out
of the organism's cells that those cells die. Antifreeze molecules
function to keep small ice crystals small or to prevent ice crystals
from forming at all. They may help freeze-tolerant organisms survive by
preventing freezing from penetrating into cells, a lethal condition.
Other insects use these molecules to resist freezing by supercooling
when they lower their body temperature below the freezing point without
UAF graduate student and project collaborator Todd Sformo found that
the Alaska Upis beetle, which has no common name, first freezes at about
minus 18.5 degrees Fahrenheit in the lab and survives temperatures down
to about 104 degrees below zero Fahrenheit.
"It seems paradoxical that we find an antifreeze molecule in an
organism that wants to freeze and that's adapted to freezing," said
Barnes, whose research group is involved in locating insects,
determining their strategies of overwintering and identifying the
mechanisms that help them get through the winter
A possible advantage of this novel molecule comes from it having the
same fatty acid that cells membranes do. This similarity, says Barnes,
may allow the molecule to become part of a cell wall and protect the
cell from internal ice crystal formation. Antifreeze molecules made of
proteins may not fit into cell membranes.
"There are many difficult studies ahead," said Barnes. "To find out
how common this biologic antifreeze is and how it actually prevents
freezing and where exactly it's located."
This project was led by Kent Walters at the University of Notre Dame
with collaborators Anthony Serianni and John H. Duman of UND and Barnes
and Sformo of UAF and was published in the Dec. 1 issue of the journal
Proceedings of the National Academy of Sciences.
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