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ELECTRON MICROSCOPE OBSERVATIONS ON MYOSIN FROM PHYSARUM POLYCEPHALUM
Myosin has been separated from Physarum polycephalum actomyosin in confirmation of the results of Hatano and Tazawa. In an intermediate step, myosin-enriched actomyosin has also been obtained. The mean yield of free myosin was 4.4 mg from 100 g of mold. It was obtained as water-clear solutions at µ...
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Formato: | Texto |
Lenguaje: | English |
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The Rockefeller University Press
1972
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2108659/ https://www.ncbi.nlm.nih.gov/pubmed/5061886 |
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author | Nachmias, Vivianne T. |
author_facet | Nachmias, Vivianne T. |
author_sort | Nachmias, Vivianne T. |
collection | PubMed |
description | Myosin has been separated from Physarum polycephalum actomyosin in confirmation of the results of Hatano and Tazawa. In an intermediate step, myosin-enriched actomyosin has also been obtained. The mean yield of free myosin was 4.4 mg from 100 g of mold. It was obtained as water-clear solutions at µ = 0.055 with calcium ATPase activity of up to 0.5 µM P(i)/min per mg. Negatively stained preparations were examined by electron microscopy. Physarum myosin in 0.5 M KCl interacted with actin from rabbit skeletal muscle to form polarized arrowhead complexes similar to but less regular than those of natural actomyosin from muscle or myosin-enriched Physarum actomyosin. The Physarum myosin-enriched actomyosin at low ionic strength displayed evidence of head-to-tail and tail-to-tail aggregation attributable to the myosin component. Yet Physarum myosin alone did not produce detectable filaments at µ = 0.055 at pH 7, 6.5, or 5.8, nor when dialyzed against 0.01 M ammonium acetate, nor when the dielectric constant of the medium was reduced. However, aggregation approaching the extent of ‘thick filaments’ up to 0.3 µ long was found in some preparations of myosin-enriched actomyosin put into solutions containing adenosine triphosphate. Myosin alone in such solutions did not form filaments. The results are compatible with the idea that head-to-tail aggregations are favored by actin-myosin interactions in Physarum, possibly due to alignment of the extended or tail portions of this myosin molecule. |
format | Text |
id | pubmed-2108659 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1972 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-21086592008-05-01 ELECTRON MICROSCOPE OBSERVATIONS ON MYOSIN FROM PHYSARUM POLYCEPHALUM Nachmias, Vivianne T. J Cell Biol Article Myosin has been separated from Physarum polycephalum actomyosin in confirmation of the results of Hatano and Tazawa. In an intermediate step, myosin-enriched actomyosin has also been obtained. The mean yield of free myosin was 4.4 mg from 100 g of mold. It was obtained as water-clear solutions at µ = 0.055 with calcium ATPase activity of up to 0.5 µM P(i)/min per mg. Negatively stained preparations were examined by electron microscopy. Physarum myosin in 0.5 M KCl interacted with actin from rabbit skeletal muscle to form polarized arrowhead complexes similar to but less regular than those of natural actomyosin from muscle or myosin-enriched Physarum actomyosin. The Physarum myosin-enriched actomyosin at low ionic strength displayed evidence of head-to-tail and tail-to-tail aggregation attributable to the myosin component. Yet Physarum myosin alone did not produce detectable filaments at µ = 0.055 at pH 7, 6.5, or 5.8, nor when dialyzed against 0.01 M ammonium acetate, nor when the dielectric constant of the medium was reduced. However, aggregation approaching the extent of ‘thick filaments’ up to 0.3 µ long was found in some preparations of myosin-enriched actomyosin put into solutions containing adenosine triphosphate. Myosin alone in such solutions did not form filaments. The results are compatible with the idea that head-to-tail aggregations are favored by actin-myosin interactions in Physarum, possibly due to alignment of the extended or tail portions of this myosin molecule. The Rockefeller University Press 1972-03-01 /pmc/articles/PMC2108659/ /pubmed/5061886 Text en Copyright © 1972 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 Nachmias, Vivianne T. ELECTRON MICROSCOPE OBSERVATIONS ON MYOSIN FROM PHYSARUM POLYCEPHALUM |
title | ELECTRON MICROSCOPE OBSERVATIONS ON MYOSIN FROM PHYSARUM POLYCEPHALUM
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title_full | ELECTRON MICROSCOPE OBSERVATIONS ON MYOSIN FROM PHYSARUM POLYCEPHALUM
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title_fullStr | ELECTRON MICROSCOPE OBSERVATIONS ON MYOSIN FROM PHYSARUM POLYCEPHALUM
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title_full_unstemmed | ELECTRON MICROSCOPE OBSERVATIONS ON MYOSIN FROM PHYSARUM POLYCEPHALUM
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title_short | ELECTRON MICROSCOPE OBSERVATIONS ON MYOSIN FROM PHYSARUM POLYCEPHALUM
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title_sort | electron microscope observations on myosin from physarum polycephalum |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2108659/ https://www.ncbi.nlm.nih.gov/pubmed/5061886 |
work_keys_str_mv | AT nachmiasviviannet electronmicroscopeobservationsonmyosinfromphysarumpolycephalum |