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Unique structural features facilitate lizard tail autotomy.

Sanggaard KW, Danielsen CC, Wogensen L, Vinding MS, Rydtoft LM, Mortensen MB, Karring H, Nielsen NC, Wang T, Thøgersen IB, Enghild JJ - PLoS ONE (2012)

Bottom Line: In the present study, we showed that tail shedding by the Tokay gecko (Gekko gecko) and the associated extracellular matrix (ECM) rupture were independent of proteolysis.Instead, lizard caudal autotomy relied on biological adhesion facilitated by surface microstructures.Results based on bio-imaging techniques demonstrated that the tail of Gekko gecko was pre-severed at distinct sites and that its structural integrity depended on the adhesion between these segments.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN), Interdiciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark.

ABSTRACT
Autotomy refers to the voluntary shedding of a body part; a renowned example is tail loss among lizards as a response to attempted predation. Although many aspects of lizard tail autotomy have been studied, the detailed morphology and mechanism remains unclear. In the present study, we showed that tail shedding by the Tokay gecko (Gekko gecko) and the associated extracellular matrix (ECM) rupture were independent of proteolysis. Instead, lizard caudal autotomy relied on biological adhesion facilitated by surface microstructures. Results based on bio-imaging techniques demonstrated that the tail of Gekko gecko was pre-severed at distinct sites and that its structural integrity depended on the adhesion between these segments.

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Related in: MedlinePlus

The muscle fibres terminate in “mushroom-shaped” structures.Scanning electron microscopy analyses of the wedge-shaped extensions (cranial margins of individual tail muscles) projecting from the proximal end of the released tail stump demonstrated the presence of “mushroom-shaped” structures at the termini of the muscle fibres after autotomy. These structures are present on all sides of the extensions except on the outer part.
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pone-0051803-g004: The muscle fibres terminate in “mushroom-shaped” structures.Scanning electron microscopy analyses of the wedge-shaped extensions (cranial margins of individual tail muscles) projecting from the proximal end of the released tail stump demonstrated the presence of “mushroom-shaped” structures at the termini of the muscle fibres after autotomy. These structures are present on all sides of the extensions except on the outer part.

Mentions: The passive shedding capacity, precut segmented nature of the tail, and lack of proteases suggested that the structural integrity was mediated by surface interactions. The surface topography of the largest interacting surface consisted of wedge-shaped muscle extensions, thus warranting a more detailed examination of their surface properties. The surface topography was analyzed by scanning electron microscopy of the proximal surface of the shed tail stump. It demonstrated the presence of “mushroom-shaped” structures with diameters of 30–80 µm at the cranial margins of the muscle termini (Fig. 4). The exterior parts of the muscles running parallel to the dermis did not contain these structures, thereby reinforcing a role in the mechanism of autotomy (Fig. 2 and Fig. 4). To characterize the surface of the wedge-shaped muscle extensions in the fracture plane further, we analyzed a shed tail stump using magnetic resonance imaging (MRI) (Fig. 5 and Movies S1–S3). Using this approach, we were able to detect both the muscle fiber terminations in the fracture plane and the muscle fiber interactions in an “intact” fracture plane. The data illustrated the interdigitation arrangement of muscles in the tail rather than a simple “end-to-end” arrangement. This design is likely to facilitate adhesion by generating a larger surface area of interaction between two successive segments. In addition, the data did not supply evidence for structures going through the fracture plane. It further supports that biological adhesion is the main mediator of contact between tail segments (Fig. 5).


Unique structural features facilitate lizard tail autotomy.

Sanggaard KW, Danielsen CC, Wogensen L, Vinding MS, Rydtoft LM, Mortensen MB, Karring H, Nielsen NC, Wang T, Thøgersen IB, Enghild JJ - PLoS ONE (2012)

The muscle fibres terminate in “mushroom-shaped” structures.Scanning electron microscopy analyses of the wedge-shaped extensions (cranial margins of individual tail muscles) projecting from the proximal end of the released tail stump demonstrated the presence of “mushroom-shaped” structures at the termini of the muscle fibres after autotomy. These structures are present on all sides of the extensions except on the outer part.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3526639&req=5

pone-0051803-g004: The muscle fibres terminate in “mushroom-shaped” structures.Scanning electron microscopy analyses of the wedge-shaped extensions (cranial margins of individual tail muscles) projecting from the proximal end of the released tail stump demonstrated the presence of “mushroom-shaped” structures at the termini of the muscle fibres after autotomy. These structures are present on all sides of the extensions except on the outer part.
Mentions: The passive shedding capacity, precut segmented nature of the tail, and lack of proteases suggested that the structural integrity was mediated by surface interactions. The surface topography of the largest interacting surface consisted of wedge-shaped muscle extensions, thus warranting a more detailed examination of their surface properties. The surface topography was analyzed by scanning electron microscopy of the proximal surface of the shed tail stump. It demonstrated the presence of “mushroom-shaped” structures with diameters of 30–80 µm at the cranial margins of the muscle termini (Fig. 4). The exterior parts of the muscles running parallel to the dermis did not contain these structures, thereby reinforcing a role in the mechanism of autotomy (Fig. 2 and Fig. 4). To characterize the surface of the wedge-shaped muscle extensions in the fracture plane further, we analyzed a shed tail stump using magnetic resonance imaging (MRI) (Fig. 5 and Movies S1–S3). Using this approach, we were able to detect both the muscle fiber terminations in the fracture plane and the muscle fiber interactions in an “intact” fracture plane. The data illustrated the interdigitation arrangement of muscles in the tail rather than a simple “end-to-end” arrangement. This design is likely to facilitate adhesion by generating a larger surface area of interaction between two successive segments. In addition, the data did not supply evidence for structures going through the fracture plane. It further supports that biological adhesion is the main mediator of contact between tail segments (Fig. 5).

Bottom Line: In the present study, we showed that tail shedding by the Tokay gecko (Gekko gecko) and the associated extracellular matrix (ECM) rupture were independent of proteolysis.Instead, lizard caudal autotomy relied on biological adhesion facilitated by surface microstructures.Results based on bio-imaging techniques demonstrated that the tail of Gekko gecko was pre-severed at distinct sites and that its structural integrity depended on the adhesion between these segments.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN), Interdiciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark.

ABSTRACT
Autotomy refers to the voluntary shedding of a body part; a renowned example is tail loss among lizards as a response to attempted predation. Although many aspects of lizard tail autotomy have been studied, the detailed morphology and mechanism remains unclear. In the present study, we showed that tail shedding by the Tokay gecko (Gekko gecko) and the associated extracellular matrix (ECM) rupture were independent of proteolysis. Instead, lizard caudal autotomy relied on biological adhesion facilitated by surface microstructures. Results based on bio-imaging techniques demonstrated that the tail of Gekko gecko was pre-severed at distinct sites and that its structural integrity depended on the adhesion between these segments.

Show MeSH
Related in: MedlinePlus