TY  - JOUR
AU  - Nickel, M.
AU  - Scheer, C.
AU  - Hammel, J. U.
AU  - Herzen, J.
AU  - Beckmann, F.
AU  - DESY
TI  - The contractile sponge epithelium sensu lato - body contraction of the demosponge Tethya wilhelma is mediated by the pinacoderm
JO  - The journal of experimental biology
VL  - 214
SN  - 0022-0949
CY  - Cambridge
PB  - Company of Biologists, HighWire Press
M1  - PHPPUBDB-17502
SP  - 1692-1698
PY  - 2011
AB  - Sponges constitute one of the two metazoan phyla that are able to contract their bodies despite a complete lack of muscle cells. Two competing hypotheses on the mechanisms behind this have been postulated to date: (1) mesohyl-mediated contraction originating from fusiform smooth muscle-like actinocytes ('myocytes') and (2) epidermal contraction originating in pinacocytes. No direct support exists for either hypothesis. The question of agonist-antagonist interaction in sponge contraction seems to have been completely neglected so far. In the present study we addressed this by studying sponge contraction kinetics. We also tested both hypotheses by carrying out volumetric studies of 3D synchrotron radiation-based x-ray microtomography data obtained from contracted and expanded specimens of Tethya wilhelma. Our results support the pinacoderm contraction hypothesis. Should mesohyl contraction be present, it is likely to be part of the antagonist system. We conclude that epithelial contraction plays a major role in sponges. Contractile epithelia sensu lato may be regarded as part of the ground pattern of the Metazoa.
KW  - Animals
KW  - Biomechanics
KW  - Body Weights and Measures
KW  - Epidermis: physiology
KW  - Epidermis: ultrastructure
KW  - Epithelium: physiology
KW  - Epithelium: ultrastructure
KW  - Microscopy, Electron, Scanning
KW  - Movement: physiology
KW  - Porifera: physiology
KW  - Synchrotrons
KW  - X-Ray Microtomography
LB  - PUB:(DE-HGF)16
C6  - pmid:21525315
UR  - <Go to ISI:>//WOS:000289935400013
DO  - DOI:10.1242/jeb.049148
UR  - https://bib-pubdb1.desy.de/record/92851
ER  -