Byssal thread

The Romans made direct use of byssal threads from noble pen shells. This ancient practice of using natural chemicals directly without modification remains the most widespread form of biotechnology. A recent innovation in this area is the expanding market for enzymes that function under extreme conditions. To appreciate the industrial value of these compounds, we must first briefly discuss enzymes and then consider some exotic organisms. 

A number of insects and other invertebrates create thin fibers, for a variety of reasons. Spiders make webs for support and to capture and encase their prey. Some bivalve mollusks create byssal threads that anchor the animal s shell to rocks or other substrate. 

Byssal thread has been used for many centuries as a very exclusive yam. The threads of the noble pen shell were the most used as they were a beautiful, iridescent, golden-bronxe colour and could reach 60 centimetres long. Hundreds of shells went into the production of, for example, one pair of gloves, as byssal thread is very fine and light. 

There is a fine example of a pair of gloves made of byssal threads in the Natural History Museum in London, where they are on display in the Invertebrate Galleries. 

Figure 6 The mussel Mytilus edulis with holdfast byssal threads. Original photograph from Messersmith research group.

Recent studies have revealed a potential role for Fe coordination in bulk cross-linking and observed self-healing behavior of the byssal thread. Iron is now believed to form coordination complexes with catechols that are capable of yielding interesting bulk mechanical behavior such as time-dependent recovery after high strain. In a follow-up study, Holten-Andersen et demonstrated self-healing... 

Figure 2.2 (a) Attachment of mussel to surface (like other mussels or rocks) by using byssal threads (Cha et al., 2008). (h) Scheme representing stmctures and proteins involved in mussel adhesion (Cha et al., 2008). (c) Mechanism of l-DOPA—mediated adhesion in mussels. The reduced DOPA hinds directly to surface resulting in adhesion (left). Cohesion is obtained by metal ion templating and oxidation chemistry (right) (Wilker, 2011). 

Fig. 4 Molecular model of reversible deformation behavior in mussel byssal threads (Copyright 2013 The American Chemical Society) [95]...

Vaccaro E, Waite JH (2001) Yield and post-yield behavior of mussel byssal thread a self-healing biomolecular material. Biomacromolecules 2 906-911... 

Byssal threads and adhesive plaques of blue mussel made of Mefp (Mytilus edulis foot protein)... 

Holten-Andersen, N., Zhao, H and Waite, J.H. (2009) Stiff coatings on compliant biofibers The cuticle of Mytdus calforrUanus byssal threads. Biochemistry, 48, 2752-2759. 

Production and storage of byssal thread cells at pH 5 through monocatechol complexes. 

Formation of bis- and triscatechol complexes in the byssal threads after exposure to seawater (pH 8). Reprinted from Waite et al. [121], Copyright 2011 National Academy of Sciences of the United States... 

With this work, Waite and coworkers were able to form a hydrogel mimicking the effect that byssal threads of mussels use to adhere on surfaces. The system is based on modified PEG, allowing possible applications in the fields of engineering and biomedicine. 

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