The Molecular Biology of Physarum polycephalum pp 217-224 | Cite as
Dynamics and Function of Microfilaments in Physarumpolycephalum as Revealed by Fluorescent Analog Cytochemistry (FAC) and Electron Microscopy
Abstract
Tetramethylrhodaminyl (TRITC)-phalloidin and isolated muscle or Physarum G-actin labeled with various fluorochromes were micro-injected into living stages of Physarum polycephalum (cell fragments and microplasmodia). Subsequent analysis of the intracellular redistribution of the molecular probes by fluorescence microscopy, video-enhancement, and digital image processing revealed that polymerization-depolymerization and contraction-relaxation cycles of the microfilament system are functionally related to changes in cell shape, protoplasmic streaming activity, and ultrastructural morphology of the specimens. In relaxed cell fragments, TRITC-phalloidin and rhodamine-isothiocyanate (RITC)-actin first diffuse randomly and then are locally incorporated into a thin cortical layer at the internal face of the plasma membrane. During Ca2+-induced contraction, the fluorescent layer starts to detach from the plasma membrane, thus causing separation of the central granuloplasm from the peripheral hyaloplasm. Thin sections of both relaxed and contracted specimens demonstrate that the fluorescent layer in living cell fragments coincides exactly with a sheath of more or less oriented microfilaments. In contrast, RITC-bovine serum albumin injected as a control is excluded from those regions that show intense fluorescence with RITC-actin and TRITC-phalloidin and the presence of an actin network by electron microscopy.
Keywords
Cell Fragment Physarum Polycephalum Internal Face Protoplasmic Streaming Fluorescent AnalogPreview
Unable to display preview. Download preview PDF.
References
- Faulstich, H., Trischmann, H., and Mayer, D., 1983, Preparation of tetramethylrhodaminyl-phalloidin and uptake of the toxin into short-term cultured hepatocytes by endocytosis, Exp. Cell Res ., 144: 73.PubMedCrossRefGoogle Scholar
- Hatano, S., 1970, Specific effect of Ca2+ on movement of plasmodial fragment obtained by caffeine treatment, Exp. Cell Res ., 61: 199.PubMedCrossRefGoogle Scholar
- Hoffmann, H. U., Stockem, W., and Gruber, B., 1984, Dynamics of the cytoskeleton in Amoeba proteus. II. Influence of different agents on the spatial organization of microinjected fluorescein-labeled actin, Protoplasma, 119: 79.CrossRefGoogle Scholar
- Kamiya, N., 1959, Protoplasmic streaming, in: “protoplasmatologia VIII/3/a”, L. V. Heilbrunn and F. Weber, eds., p. 1, Springer, Wien.Google Scholar
- Kreis, T. E., and Birchmeier, W., 1982, Microinjection of fluorescently labeled proteins into living cells with emphasis on cytoskeletal proteins, Int. Rev. Cytol ., 75: 209.PubMedCrossRefGoogle Scholar
- Kreis, T. E., and Birchmeier, W., 1982, Microinjection of fluorescently labeled proteins into living cells with emphasis on cytoskeletal proteins, Int. Rev. Cytol ., 75: 209.PubMedCrossRefGoogle Scholar
- Kreis, T. E., and Birchmeier, W., 1982, Microinjection of fluorescently labeled proteins into living cells with emphasis on cytoskeletal proteins, Int. Rev. Cytol ., 75: 209.PubMedCrossRefGoogle Scholar
- Kukulies, J., and Stockem, W., 1985b, Function of the microfilament system in living cell fragments of Physarum polycephalum as revealed by microinjection of fluorescent analogs, Cell Tissue Res ., 242: 323.CrossRefGoogle Scholar
- Kukulies,, J., Stockem, W., and Achenbach, F., 1984, Distribution and dynamics of fluorochromed actin in living stages of Physarum polycephalum, Eur. J. Cell. Biol ., 35: 235.PubMedGoogle Scholar
- Kukulies, J., Stockem, W., and Wohlfarth-Bottermann, K. E., 1983, Caffeine-induced surface blebbing and budding in the acellular slime mold Physarum polycephalum, Z. Naturforsch ., 38c: 589.Google Scholar
- Sato, H., Hatano, S., and Sato, Y., 1981, Contractility and protoplasmic streaming preserved in artificially induced plasmodial fragments, the “caffeine drops”, Protoplasma, 109: 187.CrossRefGoogle Scholar
- Taylor, D. L., and Wang, Y. L. 1980, Fluorescently labelled molecules as probes of the structure and function of living cells, Nature, 284: 405.PubMedCrossRefGoogle Scholar
- Wang, Y. L., and Taylor, D. L., 1980, Preparation and characterization of a new molecular cytochemical probe, J. Histochem. Cytochem ., 28: 1198.PubMedCrossRefGoogle Scholar
- Wohlfarth-Bottermann, K.-E., 1975, Weitreichende fibrilläre Protoplasmadifferenzierungen und ihre Bedeutung für die Protoplasmaströmung. X. Die Anordnung der Actymyosinfibrillen in experimentall unbeeinflußten Protoplasmaadern von Physarum in situ, Protistologica, 11: 19.Google Scholar