Hagfish Slime Threads - The Functional Fold: Amyloid Structures in Nature - page 18

Figure 2.2 SEM of a mature gland thread cell (GTC). GTCs lose their

plasma membrane as they are ejected through the slime gland
duct and into the surrounding sea water. The vast majority of
the cytoplasmic volume in these cells is occupied by a single
protein polymer that consists of a dense bundle of 10 nm
intermediate filaments.

Upon turbulent mixing with sea water, however, the slime
quickly disperses and undergoes a remarkable transformation from
a small volume of viscous exudate into a much larger volume of
nearly transparent slime. Without turbulent mixing, slime exudate
transferred into sea water (or even ejected from a live hagfish) will
not form “proper” slime and will remain as a small coherent blob.

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The exact mechanisms that are at play during the transformation of
slime exudate into fully expanded slime are not yet fully understood;
however, some clues are available.
One thing that occurs during this transformation is the complete
unravelling and elongation of thread cell skeins into fibres that are
more than 10 cm long.

5,8

This is an impressively long structure for
something built within a single cell (although admittedly not as
impressive as chromosomal DNA, which is 500 times narrower in
width, almost 20 times longer, and packed into a structure that is
only 1/20,000 the volume of a GTC). Another thing that occurs is the
hydration and swelling of mucin vesicles as they are exposed to sea