scholarly journals Structural Aspects of Saltatory Particle Movement

1967 ◽  
Vol 50 (6) ◽  
pp. 223-239 ◽  
Author(s):  
Lionel I. Rebhun
Keyword(s):  
Smooth Muscle ◽  
Detailed Analysis ◽  
Cytoplasmic Streaming ◽  
Particle Movement ◽  
Fiber System ◽  
Mitotic Apparatus ◽  
Generating Set ◽  
Spatially Correlated ◽  
Saltatory Movement ◽  
Structural Aspects

A variety of cells possess particles which show movements statistically different from Brownian movements. They are characterized by discontinuous jumps of 2–30 µ at velocities of 0.5–5 µ/sec or more. A detailed analysis of these saltatory, jumplike movements makes it most likely that they are caused by transmission of force to the particles by a fiber system in the cell outside of the particle itself. Work with isolated droplets of cytoplasm from algae demonstrates a set of fibers involved in both cytoplasmic streaming and saltatory motion, suggesting that both phenomena are related to the same force-generating set of fibers. Analysis of a variety of systems in which streaming and/or saltatory movement occurs reveals two types of fiber systems spatially correlated with the movement, microtubules and 50 A microfilaments. The fibers in Nitella (alga) are of the microfilament type. In other systems (melanocyte processes, mitotic apparatus, nerve axons) microtubules occur. A suggestion is made, based on work on cilia, that a microtubule-microfilament complex may be present in those cases in which only microtubules appear to be present, with the microfilament closely associated with or buried in the microtubule wall. If so, then microfilaments, structurally similar to smooth muscle filaments, may be a force-generating element in a very wide variety of saltatory and streaming phenomena.

Self-organization of Rotaxane Thin Films into Spatially Correlated Nanostructures:  Morphological and Structural Aspects

2006 ◽  
Vol 128 (2) ◽  
pp. 526-532 ◽  
Author(s):  
Jean-François Moulin ◽  
Jean Crispin Kengne ◽  
Rajendra Kshirsagar ◽  
Massimilliano Cavallini ◽  
Fabio Biscarini ◽  
...  
Keyword(s):  
Thin Films ◽  
Self Organization ◽  
Spatially Correlated ◽  
Structural Aspects

scholarly journals Expression of the Giant Protein AHNAK (Desmoyokin) in Muscle and Lining Epithelial Cells

2003 ◽  
Vol 51 (3) ◽  
pp. 339-348 ◽  
Author(s):  
Benoit J. Gentil ◽  
Christian Delphin ◽  
Christelle Benaud ◽  
Jacques Baudier
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Plasma Membrane ◽  
Epithelial Cells ◽  
Smooth Muscle Cells ◽  
Detailed Analysis ◽  
Adult Mouse ◽  
Muscle Cells ◽  
Structural Support ◽  
Mouse Tissues

Here we report a detailed analysis of the expression and localization of the giant protein AHNAK in adult mouse tissues. We show that AHNAK is widely expressed in muscle cells, including cardiomyocytes, smooth muscle cells, skeletal muscle, myoepithelium, and myofibroblasts. AHNAK is also specifically expressed in epithelial cells of most lining epithelium, but is absent in epithelium with more specialized secretory or absorptive functions. In all adult tissues, the main localization of AHNAK is at the plasma membrane. A role for AHNAK in the specific organization and the structural support of the plasma membrane common to muscle and lining epithelium is discussed.

Non-muscle myosin isoforms and cell heterogeneity in developing rabbit vascular smooth muscle

1992 ◽  
Vol 101 (1) ◽  
pp. 233-246
Author(s):  
L. Giuriato ◽  
M. Scatena ◽  
A. Chiavegato ◽  
M. Tonello ◽  
G. Scannapieco ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Developmental Stages ◽  
Early Stage ◽  
Rabbit Aorta ◽  
Cell Types ◽  
Myosin Isoforms ◽  
Protein Markers ◽  
Fiber System ◽  
Developmentally Regulated

A panel of monoclonal antibodies specific for cytoskeletal and cytocontractile protein markers has been used to study the expression of vimentin, desmin and alpha-smooth muscle (SM) actin, as well as non-muscle (NM) and SM myosin isoforms, in developing rabbit aorta. Immunofluorescence experiments show that in the vascular smooth muscle cells (SMC): (1) vimentin and alpha-actin of SM-type are homogeneously expressed among SMC, since the early stage (day 19, in uterus) of development; (2) desmin is heterogeneously distributed throughout all the developmental stages examined (from day 19, foetal, to day 90, post-natal); and (3) myosin isoform content in pre- and post-natal vascular SM is different when analyzed by anti-SM myosin (SM-E7) and anti-NM myosin (NM-F6, NM-A9 and NM-G2) antibodies. SM myosin in vascular SM is present as early as day 19 in uterus, being especially evident in the region facing the lumen of aortic wall, but not in the outermost layer in which NM myosin is present exclusively. Western blotting and immunofluorescence assays indicate that the foetal aortic SM is specifically labeled by all the three anti-NM myosin antibodies. However, immunoreactivity of aortic SM with NM-F6 and NM-A9 disappears completely around birth. Conversely, NM-G2 binding is maintained during post-natal development up to day 45; between day 45 and day 90 immunoreactivity of aortic SMC with this antibody diminished progressively, without disappearing, in a small number of cells. In aortic SMC cultures from foetal and adult rabbits, NM myosin immunoreactivities appear to be differently distributed, i.e. according to the stress fiber system (NM-F6 and NM-G2), in a diffuse manner (NM-A9) or mainly localized at the level of the cortical cytoplasm (NM-G2). The fact that a different pattern of NM myosin antigenicity can also be shown in other cell types, such as in the endothelium and the cardiac pericytes as well as in the renal parenchyma, is consistent with the existence of multiple NM myosin in vascular SM isoforms whose expression is developmentally regulated.

Chopin's Alston and Alston's Chopin

2020 ◽  
Vol 38 (1) ◽  
pp. 82-120
Author(s):  
Stephanie Jordan
Keyword(s):  
Detailed Analysis ◽  
Music Theory ◽  
Dynamic Interaction ◽  
Creative Processes ◽  
Analytical Process ◽  
Film Clips ◽  
History Of ◽  
Structural Aspects

This article presents Richard Alston's re-visioning of Chopin's music through two works: Such Longing (in two versions, 2005/2015), and Mazur (2015). Alston rescues the composer from dance associations with romance and sweet sentiment and celebrates his more robust, bolder and darker gamut of expression. The article includes detailed analysis of a range of solos and duets (for two men as well as for a woman and a man). Alston is widely regarded as an exceptionally musical choreographer, and the article identifies a particular choreomusical style emerging from his work. There is discussion of structural aspects, involving both music and dance, pursuing the dynamic interaction between them, and of creative processes and changes in the dances through the history of their performance. A landmark feature of Alston's choreomusical style is to allow rhythmic detail to shift more than most other choreographers would wish, encouraging subtle changes of relation to musical beat and bar-line as movement phrases ‘breathe’ within performance. I also foreground my own analytical process, which draws from music theory as well as dance principles. Film clips and music examples, some of which incorporate aligned notes on the choreography, illustrate my analyses.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

Structural Studies on Mitotic Spindle Fibres

1978 ◽  
Vol 36 (3) ◽  
pp. 615-626
Author(s):  
J.R. Mcintosh
Keyword(s):  
Chemical Composition ◽  
Mitotic Spindle ◽  
Structural Studies ◽  
Mitotic Apparatus ◽  
Chemical Studies ◽  
Medical Interest ◽  
Spindle Fibres

The mitotic apparatus is a structure of obvious biological and medical interest, but it has proved to be a difficult cellular machine to understand. The chemical composition of the spindle is only slightly elucidated, largely because of the difficulties in preparing useful isolates of the structure. Chemical studies of the mitotic spindle have been reviewed elsewhere (Mcintosh, 1977), and will not be discussed further here. One would think that structural studies on the mitotic apparatus (MA) in situ would be straightforward, but even with this approach there is some disagreement in the results obtained with various methods and by different investigators. In this paper I will review briefly the approaches which have been used in structural studies of the MA, pointing out the strengths and problems of each approach. I will summarize the principal findings of the different methods, and identify what seem to be fruitful avenues for further work.

The Cellular Origin in Atheromatous Lesion

1970 ◽  
Vol 28 ◽  
pp. 202-203
Author(s):  
T. M. Murad ◽  
H. A. I. Newman ◽  
K. F. Kern
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Rabbit Aorta ◽  
Mixed Population ◽  
The Other ◽  
Cellular Origin ◽  
Ultrastructural Studies ◽  
Atherosclerotic Lesions ◽  
Show Evidence ◽  
Early Lesion

The origin of lipid containing cells in atheromatous lesion has been disputed. Geer in his study on atheromatous lesions of rabbit aorta, suggested that the early lesion is composed mainly of lipid-laden macrophages and the later lesion has a mixed population of macrophages and smooth muscle cells. Parker on the other hand, was able to show evidence that the rabbit lesion is primarily composed of lipid-laden cells of smooth muscle origin. The above studies and many others were done on an intact lesion without any attempt of cellular isolation previous to their ultrastructural studies. Cell isolation procedures have been established for atherosclerotic lesions through collagenase and elastase digestion Therefore this procedure can be utilized to identify the cells involved in rabbit atheroma.

Electron Probe Analysis of Muscle

1982 ◽  
Vol 40 ◽  
pp. 398-401
Author(s):  
A. V. Somlyo ◽  
H. Shuman ◽  
A. P. Somlyo
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Resting State ◽  
Binding Sites ◽  
Electron Probe ◽  
Frog Skeletal Muscle ◽  
Electron Probe Analysis ◽  
Probe Analysis

Electron probe analysis of frozen dried cryosections of frog skeletal muscle, rabbit vascular smooth muscle and of isolated, hyperpermeab1 e rabbit cardiac myocytes has been used to determine the composition of the cytoplasm and organelles in the resting state as well as during contraction. The concentration of elements within the organelles reflects the permeabilities of the organelle membranes to the cytoplasmic ions as well as binding sites. The measurements of [Ca] in the sarcoplasmic reticulum (SR) and mitochondria at rest and during contraction, have direct bearing on their role as release and/or storage sites for Ca in situ.

Neuronal and Extraneuronal Uptake of 3H-Norepinephrine in the Heart of the Active Bat: An Electron Microscopic Radioautographic Study

1973 ◽  
Vol 31 ◽  
pp. 522-523
Author(s):  
Martin Hagopian ◽  
Michael D. Gershon ◽  
Eladio A. Nunez
Keyword(s):  
Smooth Muscle ◽  
Monoamine Oxidase ◽  
Vascular Smooth Muscle ◽  
Cardiac Muscle ◽  
Maximum Rate ◽  
External Medium ◽  
Extraneuronal Uptake ◽  
Electron Microscopic ◽  
Cardiac Tissues ◽  
High Affinity

The ability of cardiac tissues to take up norepinephrine from an external medium is well known. Two mechanisms, called Uptake and Uptake respectively by Iversen have been differentiated. Uptake is a high affinity system associated with adrenergic neuronal elements. Uptake is a low affinity system, with a higher maximum rate than that of Uptake. Uptake has been associated with extraneuronal tissues such as cardiac muscle, fibroblasts or vascular smooth muscle. At low perfusion concentrations of norepinephrine most of the amine taken up by Uptake is metabolized. In order to study the localization of sites of norepinephrine storage following its uptake in the active bat heart, tritiated norepinephrine (2.5 mCi; 0.064 mg) was given intravenously to 2 bats. Monoamine oxidase had been inhibited with pheniprazine (10 mg/kg) one hour previously to decrease metabolism of norepinephrine.

Structural aspects of osmoregulation in porphyra

1978 ◽  
Vol 36 (2) ◽  
pp. 412-413
Author(s):  
C. Wiencke ◽  
A. Lauchli
Keyword(s):  
Culture Medium ◽  
Point Of View ◽  
Chemical Fixation ◽  
Cellular Organization ◽  
Osmotic Adaptation ◽  
Osmotic Balance ◽  
Activity Of Enzymes ◽  
Osmotic Agents ◽  
Vacuolar System ◽  
Structural Aspects

Osmoregulatory mechanisms in algae were investigated mainly from a physiological point of view (KAUSS 1977, HELLEBUST 1976). In Porphyra two osmotic agents, i. e. floridoside/isofloridoside (KAUSS 1968) and certain ions, such as K+ and Na+(EPPLEY et al. 1960) are considered for osmotic balance. Accumulations of ions (particularly Na+) in the cytoplasm during osmotic adaptation is improbable, because the activity of enzymes is generally inhibited by high ionic concentrations (FLOWERS et al. 1977).The cellular organization of Porphyra was studied with special emphasis on the development of the vacuolar system under different hyperosmotic conditions. Porphyra was cultivated at various strengths of the culture medium ASP 12 (PROVASOLI 1961) ranging from normal to 6 times concentrated (6x) culture medium. Por electron microscopy freeze fracturing was used (specimens fixed in 2% glutaraldehyde and incubated in 30% glycerol, preparation in a BALZERS BA 360 M apparatus), because chemical fixation gave poor results.

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