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J Exp Biol. 2004 Dec;207(Pt 26):4515-24.

Kinetics and rhythm of body contractions in the sponge Tethya wilhelma (Porifera: Demospongiae).

Author information

  • Department of Zoology, Biological Institute, Stuttgart University, D-70550 Stuttgart, Germany. michael.nickel@bio.uni-stuttgart.de

Abstract

Sponges of the species Tethya wilhelma display rhythmic body contractions, which were analyzed by digital timelapse imaging and semi-automated image analysis. For the first time, differential, quantitative data on sponge behaviour could be obtained. The sponges are able to reduce their body volume by up to 73.3% during regular contractions. Each contraction cycle follows a characteristic pattern of four phases, permitting analysis of the kinetics of contraction and expansion. Long-term observations (for >7 days) reveal that the sponge contractions display a day-night periodicity in which contraction cycles are significantly longer during the dark hours. The contractions seem to be mediated by the pinacoderm; they are triggered locally and spread over the sponge surface at 12.5 microm s(-1). If two individuals of a clone are fused, the individual contraction rhythm of both sponges persists for several days, until a single new individual sponge is formed with a synchronized rhythm. The reported results and techniques establish T. wilhelma as a model organism for research on the development of aneural signal transduction and integration during early Metazoan evolution.

PMID:
15579547
[PubMed - indexed for MEDLINE]
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