Fine structure and cytoplasmic streaming in Physarum polycephalum

1966 ◽  
Vol 85 (3) ◽  
pp. 313-322 ◽  
Author(s):  
J. C. W. Crawley
Keyword(s):  
Fine Structure ◽  
Physarum Polycephalum ◽  
Cytoplasmic Streaming

Caffeine-Induced Surface Blebbing and Budding in the Acellular Slime Mold Physarum polycephalum

1983 ◽  
Vol 38 (7-8) ◽  
pp. 589-599 ◽  
Author(s):  
J. Kukulies ◽  
W. Stockem ◽  
K. E. Wohlfarth-Bottermann
Keyword(s):  
Plasma Membrane ◽  
Fine Structure ◽  
Surface Area ◽  
Physarum Polycephalum ◽  
Fold Increase ◽  
Total Surface Area ◽  
Slime Mold ◽  
Tris Buffer ◽  
Membrane Protrusions ◽  
Electron Microscopical

The mechanism of plasma membrane proliferation was studied in the acellular slime mold Physarum polycephalum with the aid of light and electron microscopical techniques. Treatment of protoplasmic drops with a Tris-buffered 15 mᴍ caffeine solution causes surface blebbing and budding over periods of 5-90 min. The process of surface blebbing is coupled to a 5-10-fold increase of the surface area in conjunction with characteristic changes in cytoplasmic morphol­ogy. Successive constriction of blebs exhibiting different sizes and degree of hyalo-granuloptasmic separation leads to the formation of numerous spherical caffeine droplets. During the process of surface budding and droplet formation the total surface area of the original (genuine) protoplasmic drop is not reduced, but continues to grow.Freeze-etch studies show that caffeine concomitantly causes characteristic changes in the fine structure of the plasma membrane. During the initial phase of surface blebbing the original density of intramembranous particles (IMP) is reduced from 3676/μm2 to 1669/μm2 and the PF:EF ratio (IMP/μm2 protoplasmic face: exoplasmic face) shifts from 2.4:1 to 2.8:1. When surface budding is completed the IMP-density in the plasma membrane of single caffeine droplets increases again to 2289/μm2 and the PF:EF ratio changes to 1.5:1. Simultaneously, the isolated caffeine droplets produce numerous small hyaline membrane protrusions, which are pinched off and contain no IMP. Control experiments demonstrate that Tris-buffer without caffeine also shows a weak capacity to induce surface blebbing, to change the IMP-density and the PF:EF ratio (2443/μm2; 1.5:1); but Tris-buffer fails to cause surface budding. On the other hand, different concentrations of sucrose (25-200 mᴍ) can supress to a certain degree both caffeine- and Tris-buffer-induced surface blebbing, but not caffeine-dependent surface budding.The caffeine-effect is reversible insofar as protoplasmic drops with blebbing and budding activity recover to normal morphology, fine structure and locomotion when transferred to physiological conditions.The mechanisms of successive changes in plasma membrane morphology as well as the mode of a participation of the actomyosin system in cell surface dynamics are discussed.

scholarly journals THE CHANGING PATTERN OF BIREFRINGENCE IN PLASMODIA OF THE SLIME MOLD, PHYSARUM POLYCEPHALUM

1965 ◽  
Vol 25 (2) ◽  
pp. 361-374 ◽  
Author(s):  
Hiromichi Nakajima ◽  
Robert D. Allen
Keyword(s):  
Physarum Polycephalum ◽  
Cytoplasmic Streaming ◽  
Channel Wall ◽  
Polarized Light ◽  
Orthogonal Arrays ◽  
Slime Mold ◽  
Wall Material ◽  
Shuttle Streaming ◽  
Oriented Parallel ◽  
Birefringent Fibrils

Plasmodia of the acellular slime mold, Physarum polycephalum, reveal a complex and changing pattern of birefringence when examined with a sensitive polarizing microscope. Positively birefringent fibrils are found throughout the ectoplasmic region of the plasmodium. In the larger strands they may be oriented parallel to the strand axis, or arranged circularly or spirally along the periphery of endoplasmic channels. Some fibrils exist for only a few minutes, others for a longer period. Some, particularly the circular fibrils, undergo changes in birefringence as they undergo cyclic deformations. In the ramifying strand region and the advancing margin there is a tendency for fibrils of various sizes to become organized into mutually orthogonal arrays. In some plasmodia the channel wall material immediately adjacent to the endoplasm has been found to be birefringent. The sign of endoplasmic birefringence is negative, and its magnitude is apparently constant over the streaming cycle. The pattern of plasmodial birefringence and its changes during the shuttle streaming cycle of Physarum are considered in the light of several models designed to explain either cytoplasmic streaming alone or the entire gamut of plasmodial motions. The results of this and other recent physical studies suggest that both streaming and the various other motions of the plasmodium may very likely be explained in terms of coordinated contractions taking place in the fibrils which are rendered visible in polarized light.

Ultrastructural Analysis Of The Aseptate Gregarine Pterospora, A Parasite of The Bamboo Worm Axiothella Mucosa.

1999 ◽  
Vol 5 (S2) ◽  
pp. 1274-1275
Author(s):  
Stephen C. Landers
Keyword(s):  
Fine Structure ◽  
Cell Body ◽  
Cytoplasmic Streaming ◽  
The Body ◽  
Ultrastructural Analysis ◽  
State University ◽  
University Campus ◽  
Sodium Cacodylate ◽  
Main Cell

The gregarine Pterospora is a parasite found in the body cavities of bamboo worms (Polychaeta: Maldanidae). The gamont stage of Pterospora has a bizarre structure with a main cell body and multiple posterior cytoplasmic extensions (Fig. 1). The cells are found in pairs within the coelom of the host and move by cytoplasmic streaming as they fill and empty their posterior extensions. Reports of this parasite in the literature are few (see references 1 & 2 for a review) and no ultrastructural details have been published regarding the genus. This study examines the fine structure of the gamont stage with particular emphasis on the structure of the pellicle.The maldanid worm Axiothella mucosa was collected by shovel in St. Andrew Bay, Florida and returned to the Troy State University campus. Pterospora spp. gamonts were pipetted from minced setigers of the worms and fixed in 3% glutaraldehyde buffered with 0.05M sodium cacodylate, pH 7.5, for 1-6 hours.

scholarly journals A "MICROTUBULE" IN PLANT CELL FINE STRUCTURE

1963 ◽  
Vol 19 (1) ◽  
pp. 239-250 ◽  
Author(s):  
M. C. Ledbetter ◽  
K. R. Porter
Keyword(s):  
Fine Structure ◽  
Cell Walls ◽  
Cytoplasmic Streaming ◽  
Plant Cells ◽  
Cellulose Microfibrils ◽  
Adjacent Cell ◽  
Mitotic Spindles ◽  
Similar Material ◽  
Microscope Examination ◽  
Cortical Regions

This paper reports an electron microscope examination of the cortices of some plant cells engaged in wall formation. Previous studies of similar material fixed in OSO4 alone have disclosed discontinuities in the plasma membrane and other evidence of inadequate fixation. After glutaraldehyde, used as a fixative in this present study, the general preservation of cortical fine structure is greatly improved. This is shown, for example, by the first evidence of slender tubules, 230 to 270 A in diameter and of indeterminate length, in plant cells of this type. They have been found in the cortical regions of cells of two angiosperms and one gymnosperm, representing all the material so far studied following this method of fixation. The tubules are identical in morphology to those also observed here in the mitotic spindles of plant cells, except that the latter have a somewhat smaller diameter. It is noted that the cortical tubules are in a favored position to govern cytoplasmic streaming and to exert an influence over the disposition of cell wall materials. In this regard it may be of some significance that the tubules just beneath the surface of the protoplast mirror the orientation of the cellulose microfibrils of the adjacent cell walls.

Cytoplasmic Microtubules in the Leaf Glands of Phaseolus Vulgaris

1967 ◽  
Vol 2 (4) ◽  
pp. 557-562
Author(s):  
T. P. O'BRIEN
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Phaseolus Vulgaris ◽  
Virus Infection ◽  
Light Microscope ◽  
Cytoplasmic Streaming ◽  
Cortical Microtubules ◽  
Cellular Asymmetry ◽  
Perinuclear Cytoplasm ◽  
Cytoplasmic Microtubules

Preliminary observations on the fine structure of the club-shaped glands on Phaseolus vulgaris leaves are reported. The perinuclear cytoplasm of the apical cells of these glands contains an abundance of microtubules. These occur either as aggregates of 2-8 or more tubules, or they may be organized around a central core of material to form a fibre-like structure. The cells also contain cortical microtubules and are rich in rough endoplasmic reticulum and dictyosomes. The nuclei of these cells also contain a proteinaceous fibre, visible in the light microscope. The possible significance of these structures is discussed in relation to cytoplasmic streaming, maintenance of cellular asymmetry, and reaction to virus infection.

Calcium wave for cytoplasmic streaming of Physarum polycephalum

2009 ◽  
Author(s):  
Shinji Yoshiyama ◽  
Mitsuo Ishigami ◽  
Akio Nakamura ◽  
Kazuhiro Kohama
Keyword(s):  
Physarum Polycephalum ◽  
Cytoplasmic Streaming ◽  
Calcium Wave
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