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While other
mollusks like snails and mussels often secrete sticky ooze, cephalopods like
octopus and squid generally aren’t known for chemical adhesion. Hoever, members
of one squid family Idiosepiidae, are identified by their sticky secretion
organ. Idiosepius squid can be smaller than your pinky fingernail and glue
themselves to seaweed in order to hide from predators. They can then quickly
unstuck themselves for a speedy getaway. In a study published in the Journal of Marine Biological Association of
the United Kingdom, Mag. Norbert Cyran and his team from the University of
Vienna investigated Idiosepius’ adhesive organ at a microscopic level for the
first time and found that the diminutive squid makes two different types of
glue.
Many kinds of
chemical adhesion are found in nature. Barnacles are infamous for the strength
of their attachment to any surface, gripping on everything from boat hulls to
living whales. Spiders use natural adhesives to construct intricate webs. These
organisms usually use mixtures of proteins and carbohydrates to make their
glue. Humans have tapped into this, by boiling animal bones, tendons, and skin
to make the animal glue used in stringed instruments and deriving shellac from
a species of beetle in India.
Samples
of the squid skin were prepared and examined under electron microscopes. The
adhesive organ was also stained and sliced for 3-D analysis in a computer. The
outer skin layer consists of two cell layers made up of six different cell
types, which correspond to structures initially described in 1921. Three of the
different cell types are specifically restricted to the adhesive organ and are
likely linked to glue production. One type of cell was evenly spread throughout
the organ, and the other two clustered together. Both the evenly distributed
cells and the clustered cells use a similar secretion pathway, but based on
where the two types of cells are in the skin Cyran and colleagues determined
that these are two different types of secretions. Cyran proposed two different
models: in the first, the two different types function as a duo-gland system
where one secretion glues the squid to a surface and the other secretion
unsticks, and in the second model both cell groupings produce the same type of
glue. The researchers suggest more biochemical research is necessary to truly
unlock the sticking mechanism.
Further research
into Idiosepius’ glue methods could be promising. Bioadhesives could be used in
the medical field where needed, as the body might be less likely to reject a
biologically created adhesive than a synthetic one- a possible technology for
stitches. Biomimicry, or
taking ideas from structures and processes in nature for human use, can lead to
novel applications. Barnacles have been studied for their incredibly strong
glue. Idiosepius’ temporary glue could have equally useful applications. Once
the reaction is figured out, the glue-making method can be applied elsewhere.
For now, though, Idiosepius’ exact glue recipe remains a mystery.
Ultrastructural characterization of the adhesive organ of Idiosepius biserialis and Idiosepius pygmaeus (Mollusca:
Cephalopoda)
Norbert Cyran, Waltraud Klepal and Janek von Byern (2011)
Journal of the Marine Biological Association of the United Kingdom, http://journals.cambridge.org/action/displayJournal?jid=MBI&volumeId=91&bVolume=y - loc91, Volume 91, Issue 07 , November 2011 pp 1499-1510
http://journals.cambridge.org/abstract_S002531541100021X
Norbert Cyran, Waltraud Klepal and Janek von Byern (2011)
Journal of the Marine Biological Association of the United Kingdom, http://journals.cambridge.org/action/displayJournal?jid=MBI&volumeId=91&bVolume=y - loc91, Volume 91, Issue 07 , November 2011 pp 1499-1510
http://journals.cambridge.org/abstract_S002531541100021X
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