Studies on microplasmodia of Physarum polycephalum

@article{Gawlitta2004StudiesOM,
  title={Studies on microplasmodia of Physarum polycephalum},
  author={Wolfgang Gawlitta and K. V. Wolf and H. -U. Hoffmann and Wilhelm Stockem},
  journal={Cell and Tissue Research},
  year={2004},
  volume={209},
  pages={71-86}
}
SummaryDepending on the conditions of the axenic shuttle culture, microplasmodia of the acellular slime mold Physarum polycephalum can be subdivided into three classes regarding fine structural organization and protoplasmic streaming activity: (a) spherical and rod-shaped types, (b) ameboid types, and (c) symmetrical types.In ameboid microplasmodia, the motive force for the irregular protoplasmic streaming activity is generated by alternative contraction and relaxation of a membrane-associated… 

Studies on microplasmodia ofPhysarum polycephalum

Results on living microplasmodia demonstrate that the cortical microfilament system is mainly involved in motive force generation for changes of cell surface morphology and protoplasmic streaming activity, whereas the fibrillar system rather serves a stabilizing and adhering function.

Studies on microplasmodia of Physarum polycephalum

Results of the present paper indicate that the cortical actin system is mainly involved in motive force generation for alterations in cell surface morphology and locomotion activity, whereas the fibrillar actinSystem rather appears to maintain the mechanical stability of microplasmodia.

Studies on microplasmodia ofPhysarum polycephalum: II. Fine structure and function of the mucous layer

It can be concluded that the slime layer exhibits an important function with regard to the controlled transport and uptake of substances: the indentations of the cell membrane invagination system running perpendicular from the microplasmodial surface to the cell interior represent preferred pathways for the selective diffusion of macromolecules.

Periodic traction in migrating large amoeba of Physarum polycephalum

The slime mould Physarum polycephalum is a giant multinucleated cell exhibiting well-known Ca2+-dependent actomyosin contractions of its vein network driving the so-called cytoplasmic shuttle

Studies on microplasmodia of Physarum polycephalum

The present results demonstrate that actin fibrils in Physarum plasmodia are not completely decomposed and reformed every contraction-relaxation cycle, and rapid fixation and phalloidin-staining at distinct stages of the contraction- RELAXation cycle demonstrates the permanent existence of cytoplasmic actinfibrils under both isometric and isotonic conditions.

Form follows function: ultrastructure of different morphotypes of Physarum polycephalum

It is concluded that morphological information is vital for the assessment and measurement of material properties in the analysis of viscoelastic and rheological measurements in the slime mold P. polycephalum.

Function of the microfilament system in living cell fragments of Physarum polycephalum as revealed by microinjection of fluorescent analogs

Microinjection of two different molecular probes reveals 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 cell fragments.

Functional analysis of actin fibrils in Physarum polycephalum

The morphological and physiological data of the present paper are discussed with respect to the biological significance of the fibrillar microfilament system in Physarum polycephalum.

An Active Poroelastic Model for Mechanochemical Patterns in Protoplasmic Droplets of Physarum polycephalum

A two-dimensional model for the contraction patterns observed in protoplasmic droplets of Physarum polycephalum is derived and analyzed, which reproduces a large variety of wave patterns, including traveling and standing waves, turbulent patterns, rotating spirals and antiphase oscillations.

Microplasmodium Dynamics of Physarum Polycephalum

A correlation analysis of single microplasmodia monitored in bright field finds fast oscillations with a period of 1-2 minutes superimposed on slow oscillations in slime mold Physarum polycephalum, which drive the so-called shuttle streaming of endoplasmic fluid within the veins.

References

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Studies on microplasmodia ofPhysarum polycephalum: II. Fine structure and function of the mucous layer

It can be concluded that the slime layer exhibits an important function with regard to the controlled transport and uptake of substances: the indentations of the cell membrane invagination system running perpendicular from the microplasmodial surface to the cell interior represent preferred pathways for the selective diffusion of macromolecules.

Plasmalemma invaginations as characteristic constituents of plasmodia of Physarum polycephalum.

The extracellular phase within the ectoplasmic regions of the strands can be interpreted either as a result of plasmalemma invaginations from the outer border of the strand, or as a consequence of pseudopodial-like processes originating from the central core and extending into the surrounding medium.

Morphogenesis and Disassembly of the Circular Plasmalemma Invagination System in Physarum polycephalum

The differentiation as well as the disassembly of this circular invagination system in retracting endings of strands was investigated with the aid of the semithin- and ultrathin-sectioning technique.

Studies on microplasmodia ofPhysarum polycephalum: Endocytotic activity, morphology of the vacuolar apparatus and defecation mechanism

The investigation of endocytotic processes in axenically cultured microplasmodia ofPhysarum polycephalum is considerably complicated by the development of an extensive cell membrane invagination system, and the whole system was labelled by staining the extracellular slime with ruthenium red or lanthanum hydroxide.

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The results indicate that the display and contraction of the phalloidin-induced filament layer can account for the changes observed in cellular movement and cytoplasmic organization.

Effects of the actin-binding protein DNAase I on cytoplasmic streaming and ultrastructure of Amoeba proteus

The results suggest that a controlled reversible equilibrium between soluble and polymerized forms of actin is a necessary requirement for amoeboid movement.

FIBRILLAR DIFFERENTIATION IN A MICROPLASMODIUM OF THE SLIME MOLD PHYSARUM POLYCEPHALUM

  • N. Usui
  • Biology
    Development, growth & differentiation
  • 1971
To investigate the relation between protoplasmic streaming and filamentous structures observed in the cytoplasm, microplasmodia were collected from shaken cultures, agar plates and shaken cultures of the organism which had previously been plate‐cultured.

Induction of a plasmodial stage of Physarum without plasmalemma invaginations

The light and electron microscopic investigation of the original drop reveal that the time-dependent differentiation processes, e.g. actomyosin fibrillogenesis, are not inhibited by caffeine, however, caffeine hinders the regeneration of the plasmalemma invaginations in theOriginal drop (up to a drop age of 30–40 min).
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