ISSN:
1432-0878
Keywords:
Actin fibrils
;
Contractility
;
Phalloidin staining
;
Morphometry
;
Physarum polycephalum
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Fragments excised from front regions of thinspread Physarum plasmodia were used to examine a possible correlation between the periodical dynamic activity of such specimens and the spatial organization of actin fibrils. Under isotonic conditions, symmetrical contractions and relaxations of the entire fragment alternate with a period of 1–4 min, whereas under isometric conditions local contractions and relaxations occur simultaneously in different regions of the same specimen. Rapid fixation and phalloidin-staining at distinct stages of the contraction-relaxation cycle demonstrates the permanent existence of cytoplasmic actin fibrils under both isometric and isotonic conditions. During the transition from relaxation to contraction the fibrils shorten in length from 25.5 μm to 21.0 μm and increase in density from 1.2 fibrils/1000 μm2 to 2.3 fibrils/1000 μm2. The present results demonstrate that actin fibrils in Physarum plasmodia are not completely decomposed and reformed every contraction-relaxation cycle.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00313965
Permalink
