Worm Breeder's Gazette 10(1): 139

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Worms Under Pressure

L. Avery

The reason worms don't fall off an upside-down plate is surface 
tension.  The force pressing the worm to the agar surface is roughly 
the surface tension of water times the perimeter of a sagittal 
section: 10+E5 -10+E6 times the weight of the worm for a young L1.  
Because of this, I thought worms might be able to survive high-speed 
centrifugation.  Since Gary Ruvkun bet me ten dollars they wouldn't, I 
did the experiment.
The worms were very young L1s prepared by hatching eggs in the 
absence of food.  I first spun some at 100,000G (32,500 rpm in an 80Ti 
rotor).  The spin was as short as I could make it: 5 min acceleration, 
a few seconds at speed, and 5 min deceleration.  The worms were 
unaffected.  About half of them thrashed in liquid, all looked normal 
in Nomarski, and all grew up to healthy, active adults and produced 
large broods in the normal time.
Next I spun some more worms at 460,000G (70,000 rpm, as fast as our 
centrifuge would go).  These worms were all clearly abnormal in 
Nomarski.  There were usually empty spaces between the buccal cavity 
and the head cuticle, and the tail often had similar holes.  In some 
the viscera pulled away from the cuticle in other places, too.  Many 
individual cells were killed.  Most of these worms arrested as L1s, 
though some continued to move.  But some of them grew up to become 
healthy adults and produce progeny.
Spinning at high speed stresses worms in three ways: there are 
forces flattening them against the bottom of the tube (like the 
surface tension forces on a plate), a very high static pressure that 
will affect chemical reactions (e.g.  dissolution of gases, as in the 
bends), and forces causing components of the worm to sediment with 
respect to each other.  Judging from the Nomarski result, it might be 
the last of these that bothers the worms most, though they are very 
resistant to all three.