AY Honors/Shells - Advanced/Answer Key

Byssus, plural "byssi", derives from Hebrew būṣ 'fine linen,' Aramaic bus, Greek βύσσος – 'a very fine yellowish flax and the linen woven from it', Latin byssus – 'fine cotton or cotton stuff', 'silk' and via New Latin to 'sea silk'.

File:Byssus threads.gif

Bussus threads on mussels

As may be seen above, the word byssus not only refers to the excretions of seashells, as sometimes assumed, but was originally used for various fine threads and cloths.

1. An exceptionally fine and valuable fibre or cloth of ancient times. Originally used for fine flax and linens, its use was later extended to fine cottons, silks, and sea silk.
2. The long fine silky filaments excreted by several mollusks (particularly Pinna nobilis) by which they attach themselves to the sea bed, from which sea silk is manufactured. They range to 6 cm in length.
3. The stipe (stem) of certain fungi which are particularly thin and thread-like.

In mussels

Mussels use byssus to attach onto rocks and other surfaces. When a mussel's foot comes across a crevice, it creates a vacuum chamber by forcing out the air and arching up, similar to a plumber's plunger unclogging a drain. In this vacuum chamber, the byssus, made of keratin and other proteins, is spewed, and bubbles into a sticky foam. By curling its foot into a tube and pumping the foam, the mussel produces sticky threads about the size of a human hair. It varnishes the threads with another protein to end up with an adhesive.

Byssus is a remarkable adhesive that water does not degrade or deform it as it does with synthetic adhesives. This has spurred genetic engineers to insert mussel DNA into yeast cells for translating the genes into the appropriate proteins.

References

• The Compact edition of the Oxford English dictionary: complete text reproduced micrographically and Supplement. Oxford at the Clarendon Press. 1987
• Webster's Third New International Dictionary (Unabridged) 1976. G. & C. Merriam Co.
• Ecsedy, Hilda 1975. "Böz – An Exotic Cloth in the Chinese Imperial Court." Hilda Ecsedy. Altorientalische Forschungen 3: pp. 145-153.
• Starr, Cecie and Taggart, Ralph. Biology: The Unity and Diversity of Life. Belmont, CA: Thomson Learning, Inc., 2004.