| Nematocysts (stinging capsules of Cnidaria) as Donnan-potential-dominated osmotic systems. | |
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MedLine Citation:
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PMID: 2792109 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Isolated nematocysts (capsules of stinging cells in Cnidaria) from the freshwater polyp Hydra vulgaris [Weber, J., Klug, M. & Tardent, P. (1987) Comp. Biochem. Physiol. 88B, 855-862] are under a constant internal osmotic pressure of 12.5 MPa. The capsular wall which withstands this considerable pressure has an average elasticity modulus of approximately 1 GPa, enabling the cyst to swell from its relaxed state to more than double its volume. If the large concentrations of Mg2+ and Ca2+ within isolated nematocysts are substituted by alkali ions, the capsular volume increases by 15% and the final osmotic pressure rises to 15.3 MPa whereas after substitution by Ca2+ a decrease to 90% of the volume and 6.5 MPa is observed. Evidence obtained from the osmotic behavior of nematocysts, as well as data from in vitro exchange of their cations, are consistent with a physicochemical model in which the internal osmotic pressure of nematocysts and thus their ability to discharge is governed by the cationic composition of the content and the salt concentrations in the environment. |
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Authors:
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J Weber |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: European journal of biochemistry / FEBS Volume: 184 ISSN: 0014-2956 ISO Abbreviation: Eur. J. Biochem. Publication Date: 1989 Sep |
Date Detail:
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Created Date: 1989-11-17 Completed Date: 1989-11-17 Revised Date: 2007-07-23 |
Medline Journal Info:
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Nlm Unique ID: 0107600 Medline TA: Eur J Biochem Country: GERMANY, WEST |
Other Details:
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Languages: eng Pagination: 465-76 Citation Subset: IM |
Affiliation:
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Zoological Institute, University of Zürich, Switzerland. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Calcium / pharmacology Cations Hydra / cytology, physiology* Kinetics Magnesium / pharmacology Mathematics Models, Theoretical Osmolar Concentration Osmotic Pressure |
| Chemical | |
Reg. No./Substance:
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0/Cations; 7439-95-4/Magnesium; 7440-70-2/Calcium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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