Abstract
Using glycerinated spasmoneme of giant Zoothamnium sp., the physical properties of spasmoneme before and after Ca2+-induced contraction (pCa 4.5) were investigated. The volume change of spasmoneme contraction was measured under zero tension. The length and diameter decreased by about 50% of their initial value as a result of contraction, which means that contraction is nearly isotropic. Thus the volume of spasmoneme decreased drastically by 86% of its original value. The swollen ratio of extended and contracted spasmoneme were 0.07 and 0.37, respectively. Tension-extension relationships of extended and contracted spasmonemes were measured. By applying the theory of rubber elasticity, the number of segments of a chain in originally extended spasmoneme was only 3.3, i.e., the chain was almost a straight one. On the other hand, the number of segments of a chain in contracted spasmoneme was more than 100, i.e., the chain was essentially a random one. Furthermore, the total number of chains in single spasmoneme was the same in extended and contracted spasmoneme. This means that the interchain cross-links of chains were not influenced by addition or removal of Ca2+. Moreover, the molecular weight of a chain is estimated to be at most about 50 kd. By considering all these results, it is concluded that the contractile mechanism of spasmoneme originates in the intramolecular folding and unfolding induced by Ca2+ binding and detaching.
Full Text
The Full Text of this article is available as a PDF (120.5 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Allen R. D. Structures linking the myonemes, endoplasmic reticulum, and surface membranes in the contractile ciliate Vorticella. J Cell Biol. 1973 Feb;56(2):559–579. doi: 10.1083/jcb.56.2.559. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Amos W. B. Contraction and calcium binding in the vorticellid ciliates. Soc Gen Physiol Ser. 1975;30:411–436. [PubMed] [Google Scholar]
- Amos W. B. Structure and coiling of the stalk in the peritrich ciliates Vorticella and Carchesium. J Cell Sci. 1972 Jan;10(1):95–122. doi: 10.1242/jcs.10.1.95. [DOI] [PubMed] [Google Scholar]
- Asai H., Ochiai T., Fukui K., Watanabe M., Kano F. Improved preparation and cooperative calcium contraction of glycerinated Vorticella. J Biochem. 1978 Mar;83(3):795–798. doi: 10.1093/oxfordjournals.jbchem.a131974. [DOI] [PubMed] [Google Scholar]
- BOTTS J., MORALES M. F. The elastic mechanism and hydrogen bonding in actomyosin threads. J Cell Physiol. 1951 Feb;37(1):27–55. doi: 10.1002/jcp.1030370104. [DOI] [PubMed] [Google Scholar]
- HOFFMANN-BERLING H. Der Mechanismus eines neuen, von der Muskelkontraktion verschiedenen Kontraktionszyklus. Biochim Biophys Acta. 1958 Feb;27(2):247–255. doi: 10.1016/0006-3002(58)90331-7. [DOI] [PubMed] [Google Scholar]
- Hawkes R. Carchesium stalk fibrillar matrix as a highly filled polymer network. J Cell Physiol. 1977 Jan;90(1):31–40. doi: 10.1002/jcp.1040900106. [DOI] [PubMed] [Google Scholar]
- Jones A. R., Jahn T. L., Fonseca J. R. Contraction of protoplasm. IV. Cinematographic analysis of the contraction of some peritrichs. J Cell Physiol. 1970 Feb;75(1):9–19. doi: 10.1002/jcp.1040750103. [DOI] [PubMed] [Google Scholar]
- Melkonian M. Ultrastructural aspects of basal body associated fibrous structures in green algae: a critical review. Biosystems. 1980;12(1-2):85–104. doi: 10.1016/0303-2647(80)90040-4. [DOI] [PubMed] [Google Scholar]
- Moriyama Y., Hiyama S., Asai H. High-speed video cinematographic demonstration of stalk and zooid contraction of Vorticella convallaria. Biophys J. 1998 Jan;74(1):487–491. doi: 10.1016/S0006-3495(98)77806-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moriyama Y., Yasuda K., Ishiwata S., Asai H. Ca(2+)-induced tension development in the stalks of glycerinated Vorticella convallaria. Cell Motil Cytoskeleton. 1996;34(4):271–278. doi: 10.1002/(SICI)1097-0169(1996)34:4<271::AID-CM2>3.0.CO;2-B. [DOI] [PubMed] [Google Scholar]
- Weis-Fogh T., Amos W. B. Evidence for a new mechanism of cell motility. Nature. 1972 Apr 7;236(5345):301–304. doi: 10.1038/236301a0. [DOI] [PubMed] [Google Scholar]
- Yamada K., Asai H. Extraction and some properties of the proteins, Spastin B, from the spasmoneme of Carchesium polypinum. J Biochem. 1982 Apr;91(4):1187–1195. doi: 10.1093/oxfordjournals.jbchem.a133802. [DOI] [PubMed] [Google Scholar]