Mechanical adaptability of sea cucumber Cuvierian tubules involves a mutable collagenous tissue

Sea-cucumber evolve to bear mutable collagenous tissue (MCT) which enables the change of its elastic modulus by a factor of 10 within a few seconds by controlling the release amount...

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Novel non-cellular adhesion and tissue grafting in the mutable collagenous tissue of the sea cucumber Parastichopus parvimensis

Journal of Experimental Biology ◽

10.1242/jeb.201.21.3003 ◽

1998 ◽

Vol 201 (21) ◽

pp. 3003-3013 ◽

Cited By ~ 1

Author(s):

G. K. Szulgit ◽

R. E. Shadwick

Keyword(s):

Wound Healing ◽

Sea Cucumber ◽

Wound Closure ◽

Cellular Adhesion ◽

Shear Stresses ◽

Short Term ◽

Cellular Processes ◽

Collagenous Tissue ◽

External Pressures

Previous work on wound healing in holothurians (sea cucumbers) has been concerned with the relatively long-term cellular processes of wound closure and regeneration of new tissue. In this report, we characterize a short-term adhesion that is a very early step in holothurian wound healing. Dissected pieces of dermis from the sea cucumber Parastichopus parvimensis adhered to each other after only 2 h of contact, whether the cells in the tissues were intact or had been lysed. Lapshear tests showed that the breaking stresses of adhered tissues reached approximately 0.5 kPa after 24 h of contact. Furthermore, dermal allografts were incorporated into the live recipient individuals without any external pressures, sutures or artificial gels to keep them in place. Dislodging the grafts after 24 h of contact required shear stresses of approximately 14 kPa. It appears that the adhesive property of the dermis plays a key role in the initiation of this grafting.

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Interfibrillar stiffening of echinoderm mutable collagenous tissue demonstrated at the nanoscale

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1609341113 ◽

2016 ◽

Vol 113 (42) ◽

pp. E6362-E6371 ◽

Cited By ~ 19

Author(s):

Jingyi Mo ◽

Sylvain F. Prévost ◽

Liisa M. Blowes ◽

Michaela Egertová ◽

Nicholas J. Terrill ◽

...

Keyword(s):

Tensile Testing ◽

Sea Cucumber ◽

Neural Control ◽

Fibrillar Structure ◽

X Ray Diffraction ◽

X Ray ◽

Collagenous Tissue ◽

Chemically Induced ◽

Collagenous Tissues

The mutable collagenous tissue (MCT) of echinoderms (e.g., sea cucumbers and starfish) is a remarkable example of a biological material that has the unique attribute, among collagenous tissues, of being able to rapidly change its stiffness and extensibility under neural control. However, the mechanisms of MCT have not been characterized at the nanoscale. Using synchrotron small-angle X-ray diffraction to probe time-dependent changes in fibrillar structure during in situ tensile testing of sea cucumber dermis, we investigate the ultrastructural mechanics of MCT by measuring fibril strain at different chemically induced mechanical states. By measuring a variable interfibrillar stiffness (EIF), the mechanism of mutability at the nanoscale can be demonstrated directly. A model of stiffness modulation via enhanced fibrillar recruitment is developed to explain the biophysical mechanisms of MCT. Understanding the mechanisms of MCT quantitatively may have applications in development of new types of mechanically tunable biomaterials.

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