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 29 COMPARISON OF TERM PLACENTAS IN CLONED AND CONTROL PREGNANCIES IN CATTLE

2005 ◽  
Vol 17 (2) ◽  
pp. 164 ◽  
Author(s):  
C.A. Batchelder ◽  
M. Bertolini ◽  
K.A. Hoffert ◽  
J.B. Mason ◽  
A.L. Moyer ◽  
...  
Keyword(s):  
Surface Area ◽  
Fetal Loss ◽  
Fold Increase ◽  
Total Surface Area ◽  
Placental Development ◽  
Ovarian Cell Lines ◽  
Term Delivery ◽  
Type C ◽  
And Control

Somatic cell nuclear transfer is associated with high incidence of fetal loss, late-term pregnancy complications, perinatal mortality, and abnormal placental development. Several groups have described abnormalities of early and mid-gestation cloned placentas (Hill et al. 2000 Biol. Reprod. 63, 1787–1794; Lee et al. 2004 Biol. Reprod. 70, 1–11). The objective of our study was to characterize differences in the placentas of clones and control calves at term delivery. Clones were produced from ovarian cell lines from two donors (Holstein, n = 5; Hereford, n = 2). Breed-matched controls included AI (Holstein, n = 3) and embryo transfer (Holstein, n = 3; Hereford n = 3) calves. All calves were delivered alive with no visible birth defects between Days 273 and 280 of gestation, and placentas were recovered for measurement and morphological analysis. When possible, pregnancies were delivered via caesarian section, and the entire uterus was recovered for classification of anatomical shape of placentomes. Each placentome was measured, weighed, and classified by type as (A) engulfing mushroom-like; (B) sub-engulfing mushroom-like; (C) flattened, non-engulfing; and (D) convex (adapted from Penninga and Longo 1998 Placenta 19, 187–193, for sheep). Mean number of placentomes per placenta was significantly greater in controls than clones, while total mass of placentomes in the pregnant horn was significantly greater in clones than in controls (Table 1). Total surface area of placentomes in the pregnant horn tended to be larger and more variable in clones (range: 2710–7450 cm2) than in controls (range: 3120–5030 cm2; P < 0.10). A two-fold increase was observed in cloned placentas, as compared with control placentas, in mean surface area per placentome and mass per placentome. Anatomically, cloned placentas differed from controls in the percentage of placentomes classified Type A (controls > clones) and Type C (clones > controls). Other abnormalities noted in cloned placentas included moderate to severe edema, teratomas, enlarged vessels, and large areas devoid of placentation. All clones and 2/9 controls displayed enlarged umbilical vessels. Significant placental abnormalities were observed in all cloned pregnancies. Table 1. Placental characteristics of term cloned and control pregnancies

Ca-Histochemistry in slime mold plasmodia

1978 ◽  
Vol 36 (2) ◽  
pp. 130-131
Author(s):  
Ulrich Dierkes
Keyword(s):  
Physarum Polycephalum ◽  
Carbon Coating ◽  
Freeze Drying ◽  
Freeze Fracture ◽  
Freeze Substitution ◽  
Uranyl Acetate ◽  
Slime Mold ◽  
Staining Procedure ◽  
Protoplasmic Streaming ◽  
Intracellular Ca

Calcium is supposed to play an important role in the control of protoplasmic streaming in slime mold plasmodia. The motive force for protoplasmic streaming is generated by the interaction of actin and myosin. This contraction is supposed to be controlled by intracellular Ca-fluxes similar to the triggering system in skeleton muscle. The histochemical localisation of calcium however is problematic because of the possible diffusion artifacts especially in aquous media.To evaluate this problem calcium localisation was studied in small pieces of shock frozen (liquid propane at -189°C) plasmodial strands of Physarum polycephalum, which were further processed with 3 different methods: 1) freeze substitution in ethanol at -75°C, staining in 100% ethanol with 1% uranyl acetate, and embedding in styrene-methacrylate. For comparison the staining procedure was omitted in some preparations. 2)Freeze drying at about -95°C, followed by immersion with 100% ethanol containing 1% uranyl acetate, and embedding. 3) Freeze fracture, carbon coating and SEM investigation at temperatures below -100° C.

Ultrastructure of the soil fungus, Geomyces pannorus

1984 ◽  
Vol 42 ◽  
pp. 738-739
Author(s):  
J. A. Traquair ◽  
E. G. Kokko
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fine Structure ◽  
Low Temperatures ◽  
Soil Fungus ◽  
Organic Soils ◽  
Anatomical Studies ◽  
Transmission Electron ◽  
Electron Microscopical ◽  
Scanning Electron

With the advent of improved dehydration techniques, scanning electron microscopy has become routine in anatomical studies of fungi. Fine structure of hyphae and spore surfaces has been illustrated for many hyphomycetes, and yet, the ultrastructure of the ubiquitous soil fungus, Geomyces pannorus (Link) Sigler & Carmichael has been neglected. This presentation shows that scanning and transmission electron microscopical data must be correlated in resolving septal structure and conidial release in G. pannorus.Although it is reported to be cellulolytic but not keratinolytic, G. pannorus is found on human skin, animals, birds, mushrooms, dung, roots, and frozen meat in addition to various organic soils. In fact, it readily adapts to growth at low temperatures.

A freeze-fracture-etched study of the physarum polycephalum plasma membrane during early formation of the macroplasmodial stage

1993 ◽  
Vol 51 ◽  
pp. 346-347
Author(s):  
Randolph W. Taylor ◽  
Henrie Treadwell
Keyword(s):  
Plasma Membrane ◽  
Life Cycle ◽  
Growth Phase ◽  
Filter Paper ◽  
Physarum Polycephalum ◽  
Freeze Fracture ◽  
Petri Dish ◽  
Wire Screen ◽  
Wide Mouth ◽  
Sterile Filter

The plasma membrane of the Slime Mold, Physarum polycephalum, process unique morphological distinctions at different stages of the life cycle. Investigations of the plasma membrane of P. polycephalum, particularly, the arrangements of the intramembranous particles has provided useful information concerning possible changes occurring in higher organisms. In this report Freeze-fracture-etched techniques were used to investigate 3 hours post-fusion of the macroplasmodia stage of the P. polycephalum plasma membrane.Microplasmodia of Physarum polycephalum (M3C), axenically maintained, were collected in mid-expotential growth phase by centrifugation. Aliquots of microplasmodia were spread in 3 cm circles with a wide mouth pipette onto sterile filter paper which was supported on a wire screen contained in a petri dish. The cells were starved for 2 hrs at 24°C. After starvation, the cells were feed semidefined medium supplemented with hemin and incubated at 24°C. Three hours after incubation, samples were collected randomly from the petri plates, placed in plancettes and frozen with a propane-nitrogen jet freezer.

Characterization of a Motile Cellular Domain Arising During the Amoebo-Flagellate Transformation of Physarum Polycephalum

1980 ◽  
Vol 38 ◽  
pp. 552-553
Author(s):  
K.I. Pagh ◽  
M.R. Adelman
Keyword(s):  
Cell Shape ◽  
Physarum Polycephalum ◽  
Slime Mold ◽  
Live Cells ◽  
Cellular Domain

Unicellular amoebae of the slime mold Physarum polycephalum undergo marked changes in cell shape and motility during their conversion into flagellate swimming cells (l). To understand the processes underlying motile activities expressed during the amoebo-flagellate transformation, we have undertaken detailed investigations of the organization, formation and functions of subcellular structures or domains of the cell which are hypothesized to play a role in movement. One focus of our studies is on a structure, termed the “ridge” which appears as a flattened extension of the periphery along the length of transforming cells (Fig. 1). Observations of live cells using Nomarski optics reveal two types of movement in this region:propagation of undulations along the length of the ridge and formation and retraction of filopodial projections from its edge. The differing activities appear to be associated with two characteristic morphologies, illustrated in Fig. 1.

scholarly journals A Facile One-Pot Approach to the Synthesis of Gd-Eu Based Metal-Organic Frameworks and Applications to Sensing of Fe3+ and Cr2O72− Ions

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1679
Author(s):  
Roberta Puglisi ◽  
Anna L. Pellegrino ◽  
Roberto Fiorenza ◽  
Salvatore Scirè ◽  
Graziella Malandrino
Keyword(s):  
Surface Area ◽  
Metal Organic Frameworks ◽  
3D Structure ◽  
Inorganic Ions ◽  
Total Surface Area ◽  
One Pot ◽  
Green Approach ◽  
Metal Organic ◽  
Ft Ir ◽  
Xrd Patterns

Gadolinium metal-organic frameworks (Gd-MOFs) and Eu-doped Gd-MOFs have been synthesized through a one-pot green approach using commercially available reagents. The 1,4-benzenedicarboxylic acid (H2-BDC) and 2,6-naphthalenedicarboxylic acid (H2-NDC) were chosen as ditopic organic linkers to build the 3D structure of the network. The Gd-MOFs were characterized using powder X-ray diffraction (XRD), FT-IR spectroscopy, field emission scanning electron microscopy (FE-SEM) and N2 adsorption–desorption analysis. The Gd-MOF structures were attributed comparing the XRD patterns, supported by the FT-IR spectra, with data reported in the literature for Ln-MOFs of similar lanthanide ionic radius. FE-SEM characterization points to the effect of the duration of the synthesis to a more crystalline and organized structure, with grain dimensions increasing upon increasing reaction time. The total surface area of the MOFs has been determined from the application of the Brunauer–Emmett–Teller method. The study allowed us to correlate the processing conditions and ditopic linker dimension to the network surface area. Both Gd-MOF and Eu-doped Gd-MOF have been tested for sensing of the inorganic ions such as Fe3+ and Cr2O72−.

NSAM-derived total surface area versus SMPS-derived “mobility equivalent” surface area for different environmentally relevant aerosols

2013 ◽  
Vol 66 ◽  
pp. 1-11 ◽  
Author(s):  
Megat-Azman Mokhtar ◽  
Rohan Jayaratne ◽  
Lidia Morawska ◽  
Mandana Mazaheri ◽  
Nic Surawski ◽  
...  
Keyword(s):  
Surface Area ◽  
Total Surface Area
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