Cargando…
THE CONTRACTILE PROCESS IN THE CILIATE, STENTOR COERULEUS : I. The Role of Microtubules and Filaments
The structural basis for the function of microtubules and filaments in cell body contractility in the ciliate Stentor coeruleus was investigated. Cells in the extended state were obtained for ultrastructural analysis by treatment before fixation with a solution containing 10 mM EGTA, 50–80 mM Tris,...
Autores principales: | , |
---|---|
Formato: | Texto |
Lenguaje: | English |
Publicado: |
The Rockefeller University Press
1973
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2108994/ https://www.ncbi.nlm.nih.gov/pubmed/4633444 |
_version_ | 1782139169006419968 |
---|---|
author | Huang, B. Pitelka, D. R. |
author_facet | Huang, B. Pitelka, D. R. |
author_sort | Huang, B. |
collection | PubMed |
description | The structural basis for the function of microtubules and filaments in cell body contractility in the ciliate Stentor coeruleus was investigated. Cells in the extended state were obtained for ultrastructural analysis by treatment before fixation with a solution containing 10 mM EGTA, 50–80 mM Tris, 3 mM MgSO(4), 7.5 mM NH(4)Cl, 10 mM phosphate buffer (pH 7.1). The response of Stentor to changes in the divalent cation concentrations in this solution suggests that Ca(+2) and Mg(+2) are physiologically important in the regulation of ciliate contractility. The generation of motive force for changes in cell length in Stentor resides in two distinct longitudinal cortical fiber systems, the km fibers and myonemes. Cyclic changes in cell length are associated with (a) the relative sliding of parallel, overlapping microtubule ribbons in the km fibers, and (b) a distinct alteration in the structure of the contractile filaments constituting the myonemes. The microtubule and filament systems are distinguished functionally as antagonistic contractile elements. The development of motive force for cell extension is accomplished by active microtubule-to-microtubule sliding generated by specific intertubule bridges. Evidence is presented which suggests that active shortening of contractile filaments, reflected in a reversible structural transformation of dense 4-nm filaments to tubular 10–12-nm filaments, provides the basis for rapid cell contraction. |
format | Text |
id | pubmed-2108994 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1973 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-21089942008-05-01 THE CONTRACTILE PROCESS IN THE CILIATE, STENTOR COERULEUS : I. The Role of Microtubules and Filaments Huang, B. Pitelka, D. R. J Cell Biol Article The structural basis for the function of microtubules and filaments in cell body contractility in the ciliate Stentor coeruleus was investigated. Cells in the extended state were obtained for ultrastructural analysis by treatment before fixation with a solution containing 10 mM EGTA, 50–80 mM Tris, 3 mM MgSO(4), 7.5 mM NH(4)Cl, 10 mM phosphate buffer (pH 7.1). The response of Stentor to changes in the divalent cation concentrations in this solution suggests that Ca(+2) and Mg(+2) are physiologically important in the regulation of ciliate contractility. The generation of motive force for changes in cell length in Stentor resides in two distinct longitudinal cortical fiber systems, the km fibers and myonemes. Cyclic changes in cell length are associated with (a) the relative sliding of parallel, overlapping microtubule ribbons in the km fibers, and (b) a distinct alteration in the structure of the contractile filaments constituting the myonemes. The microtubule and filament systems are distinguished functionally as antagonistic contractile elements. The development of motive force for cell extension is accomplished by active microtubule-to-microtubule sliding generated by specific intertubule bridges. Evidence is presented which suggests that active shortening of contractile filaments, reflected in a reversible structural transformation of dense 4-nm filaments to tubular 10–12-nm filaments, provides the basis for rapid cell contraction. The Rockefeller University Press 1973-06-01 /pmc/articles/PMC2108994/ /pubmed/4633444 Text en Copyright © 1973 by The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/). |
spellingShingle | Article Huang, B. Pitelka, D. R. THE CONTRACTILE PROCESS IN THE CILIATE, STENTOR COERULEUS : I. The Role of Microtubules and Filaments |
title | THE CONTRACTILE PROCESS IN THE CILIATE, STENTOR COERULEUS
: I. The Role of Microtubules and Filaments |
title_full | THE CONTRACTILE PROCESS IN THE CILIATE, STENTOR COERULEUS
: I. The Role of Microtubules and Filaments |
title_fullStr | THE CONTRACTILE PROCESS IN THE CILIATE, STENTOR COERULEUS
: I. The Role of Microtubules and Filaments |
title_full_unstemmed | THE CONTRACTILE PROCESS IN THE CILIATE, STENTOR COERULEUS
: I. The Role of Microtubules and Filaments |
title_short | THE CONTRACTILE PROCESS IN THE CILIATE, STENTOR COERULEUS
: I. The Role of Microtubules and Filaments |
title_sort | contractile process in the ciliate, stentor coeruleus
: i. the role of microtubules and filaments |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2108994/ https://www.ncbi.nlm.nih.gov/pubmed/4633444 |
work_keys_str_mv | AT huangb thecontractileprocessintheciliatestentorcoeruleusitheroleofmicrotubulesandfilaments AT pitelkadr thecontractileprocessintheciliatestentorcoeruleusitheroleofmicrotubulesandfilaments AT huangb contractileprocessintheciliatestentorcoeruleusitheroleofmicrotubulesandfilaments AT pitelkadr contractileprocessintheciliatestentorcoeruleusitheroleofmicrotubulesandfilaments |