Marine mussels secrete strong underwater adhesives called byssus threads to attach themselves to surfaces. The byssus threads are made of proteins like polyphenolic proteins and are produced when the mussel's foot encounters a surface. Scientists are studying blue mussel adhesive proteins to understand mussel adhesion and develop strong, water-resistant natural adhesives for applications like medicine. However, fully replicating the mussel's adhesive process has proven challenging.

1. BYSSAL ADHESIVES
M.MEENAKSHI,
DEPT OF MICROBIOLOGY,
SRI RAMAKRISHNA CAS FOR WOMEN,
COIMBATORE

2. BYSSAL ADHESIVES
A byssus /ˈbɪsəs/ is a bundle of filaments
secreted by many species of bivalve
mollusk that function to attach the mollusk
to a solid surface. Species from several
families of clams have a byssus, including
the pen shells, the true mussels and the
false mussels: the Pinnidae, the Mytilidae
and the Dreissenidae.

3. PRODUCTION OF ADHESIVES
 Byssus filaments are created by certain kinds of marine and freshwater bivalve mollusks, which use the
byssus to attach themselves to rocks, substrates, or seabeds. In edible mussels, the inedible byssus is
commonly known as the "beard", and is removed before cooking.
 Byssus often refers to the long, fine, silky threads secreted by the large Mediterranean pen shell, Pinna
nobilis. The byssus threads from this Pinna species can be up to 6 cm in length and have historically been
made into cloth.
 Many species of mussels secrete byssus threads to anchor themselves to surfaces, with families including
the Arcidae, Mytilidae, Anomiidae, Pinnidae, Pectinidae, Dreissenidae, and Unionidae.
 When a mussel's foot encounters a crevice, it creates a vacuum chamber by forcing out the air and arching
up, similar to a plumber's plunger unclogging a drain. The byssus, which is made of keratin, quinone-tanned
proteins (polyphenolic proteins), and other proteins, is spewed into this chamber in liquid form, 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. The mussel then varnishes the threads with another protein,
resulting in an adhesive.
 Byssus is a remarkable adhesive, one that is neither degraded nor deformed by water as synthetic
adhesives] This property has spurred genetic engineers to insert mussel DNA into yeast cells for translating
the genes into the appropriate proteins

4. ULTRASTRUCTURE OF BYSSAL ADHESIVE

5. MARINE MUSSEL

6. M. edulis attachment to (a) seaweed, (b) other mussels, and (c) a stainless steel surface.
Hydroxylation of tyrosine residues in M. edulis polyphenolic proteins-

7. UNDERSTANDING MARINE MUSSEL ADHESION
 Identifying the proteins that have a role in underwater adhesion by marine mussels,
research efforts have focused on identifying the genes responsible for the adhesive
proteins, environmental factors that may influence protein production, and
strategies for producing natural adhesives similar to the native mussel adhesive
proteins.
 The production-scale availability of recombinant mussel adhesive proteins will
enable researchers to formulate adhesives that are water-impervious and
ecologically safe and can bind materials ranging from glass, plastics, metals, and
wood to materials, such as bone or teeth, biological organisms, and other chemicals
or molecules.
 Unfortunately, as of yet scientists have been unable to duplicate the processes that
marine mussels use to create adhesive structures.
 adhesive proteins identified in the blue mussel, Mytilus edulis, and introduces our
research interests and discusses the future for continued research related to mussel
adhesion.

8. BIOLOGICAL TARGET
• KeratinA hard, durable insoluble, structural protein that is the primary component of horns, hoofs,
feathers, skin, hair, and nails; a scleroprotein
• Elastin An insoluble protein found in connective tissue and known for its elasticity and similarity to
collagen; a scleroprotein
• Collagen A tough, insoluble, inelastic protein with high tensile strength that serves as the support
structure in skin, tendons, and bone; a scleroprotein
• Silks High tensile strength protein fibers that contain various proteins (fibroin, spidroin); most commonly
from spiders and silkworms
• Fibrin (and other coagulation system proteins) A sticky, insoluble, clot-forming protein formed by
constituents in the blood; a scleroprotein
• Chitin A specialized carbohydrate containing nitrogen (nitrogenous polysaccharide); found in the cell walls
of certain fungi and in the exoskeletons of arthropods
• Cellulose An insoluble complex carbohydrate (polysaccharide composed of linked glucose units);
main constituent of the cell walls of plants
• Mucin A nitrogenous, conjugated protein (protein linked to a sugar) found in mucous secretions; acts as a lubricant
and protects body surfaces

9. MARINE MUSSELS
 Marine mussels, such as the blue mussel, M. edulis, attach to a variety of surfaces
in an aqueous environment by using a natural adhesive that is incredibly strong and
durable.
 There are no synthetic glues that can be similarly applied in an aqueous
environment and are impervious to water and turbulent forces.
 Previous research has shown that one of the proteins in the adhesive, Mytilus
edulis foot protein 1 (Mefp-1), bonds to glass, plastic, wood, concrete, and Teflon®.
Nine other adhesive-related proteins from M. edulis have been identified to date. A
tenth is implicated but has not been isolated. The precise mechanism for assembly
of the ten proteins-Mefp-1, -2, -3, -4, -5; collagens such as precollagen-D, -P
(variant P22 and P33), and -NG; proximal matrix thread protein (PMTP-1 and -1a);
and a polyphenol oxidase—is not understood.
 There also may be additional proteins involved in the formation of the adhesive.
Figure 1 illustrates adhesion of M. edulis to seaweed, other mussels, and a stainless
steel surface.

10. APPLICATIONS