The Fine Structure of Calcoblasts in the Regenerating Sea Urchin Spine

1972 ◽  
Vol 30 ◽  
pp. 162-163
Author(s):  
Barry M. Heatfield ◽  
Dorothy F. Travis
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Calcium Carbonate ◽  
Sea Urchin ◽  
Basal Lamina ◽  
Strongylocentrotus Purpuratus ◽  
Extracellular Fluid ◽  
Cell Types ◽  
Thin Sections ◽  
Sea Urchin Spine

The endoskeleton of echinoderms is composed of fenestrated calcium carbonate (calcite) permeated by interconnecting channels filled with a variety of cell-types and extracellular fluid containing collagen fibrils. To identify and characterize skeletogenic cells and explore the mechanism of skeleton growth in echinoderms, tissues of regenerating spines of the sea urchin Strongylocentrotus purpuratus were examined by electron microscopy.The tip of the young regenerate is composed of two layers of tissue: an outer epidermis and an inner calcified dermis separated by a thin basal lamina (Fig. 1). In the apical dermis the skeleton consists of longitudinally oriented microspines interconnected by horizontal calcite bridges. During preparation of thin sections, skeletal mineral was lost, leaving a hole, indicated by (ms) in Figs. 1, 2, and 4.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

scholarly journals STUDIES ON THE MODE OF ACTION OF EXCESS OF VITAMIN A

1963 ◽  
Vol 17 (1) ◽  
pp. 111-121 ◽  
Author(s):  
Audrey M. Glauert ◽  
Mary R. Daniel ◽  
J. A. Lucy ◽  
J. T. Dingle
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Vitamin A ◽  
Phase Contrast ◽  
Phase Contrast Microscopy ◽  
Intact Cells ◽  
Thin Sections ◽  
Initial Effect ◽  
Contrast Microscopy ◽  
Site Of Action

Rabbit erythrocytes have been haemolysed by treatment with vitamin A alcohol and the sequence of changes in the fine structure of the cells during lysis has been investigated by phase contrast microscopy of intact cells and electron microscopy of thin sections. The initial effect of the vitamin, which occurs within 1 minute, is the production of cells of bizarre appearance which have a greatly increased surface area relative to untreated cells. Large indentations appear in the surfaces of the cells, and vacuoles are formed from the indentations by a process that resembles micropinocytosis. The cells then become spherical and loss of haemoglobin begins as breaks appear in the membranes of some cells; finally, ghosts are produced that are no longer spherical but still contain numerous vacuoles. These observations support the thesis that one site of action of vitamin A is at lipoprotein membranes.

scholarly journals THE SARCOPLASMIC RETICULUM IN MUSCLE CELLS OF AMBLYSTOMA LARVAE

1956 ◽  
Vol 2 (4) ◽  
pp. 163-170 ◽  
Author(s):  
Keith R. Porter
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Sarcoplasmic Reticulum ◽  
Constant Width ◽  
Muscle Cells ◽  
Cell Types ◽  
Thin Sections ◽  
System A ◽  
Structural Relationships ◽  
Complex Membrane

Electron microscopy of thin sections of muscle fibers in myotomes of Amblystoma larvae has revealed the presence of a complex, membrane-limited system of canaliculi and vesicles which form a lace-like reticulum around and among the myofibrils. This seems to correspond to the sarcoplasmic reticulum of the earlier light microscopists and the endoplasmic reticulum of other cell types. The elements constituting the reticulum are disposed in a pattern which bears a constant relation to the bands of the adjacent myofibrils and is therefore repeated in each sarcomere. At the H band the system is transversely continuous but not so at other levels. Longitudinally continuity is interrupted at the Z bands where large vesicles belonging to adjacent sarcomere segments of the system face off on opposite sides of the band. The opposing faces of these vesicles are flat and separated by a space of more or less constant width, in which are located small, finger-shaped vesicles. In view of these and other close structural relationships with the myofibrils it seems appropriate to assign to the system a role in the conduction of the excitatory impulse.

scholarly journals Actin in triton-treated cortical preparations of unfertilized and fertilized sea urchin eggs.

1979 ◽  
Vol 82 (1) ◽  
pp. 212-226 ◽  
Author(s):  
A Spudich ◽  
J A Spudich
Keyword(s):  
Electron Microscopy ◽  
Sea Urchin ◽  
Actin Filaments ◽  
Cell Types ◽  
Optical Diffraction ◽  
Muscle Actin ◽  
Sea Urchin Eggs ◽  
Inner Surface ◽  
Low Ionic Strength ◽  
Helical Parameters

Triton-treated cortical fragments of unfertilized and fertilized sea urchin eggs prepared in the presence of greater than or equal to 5 mM EGTA contain 15-30% of the total egg actin. However, actin filaments are not readily apparent by electron microscopy on the cortical fragments of unfertilized eggs but are numerous on those of fertilized eggs. The majority of the actin associated with cortical fragments of unfertilized eggs is solubilized by dialysis against a low ionic strength buffer at pH 7.5. This soluble actin preparation (less than 50% pure actin) does not form proper filaments in 0.1 M KCl and 3 mM MgCl2, whereas actin purified from this preparation does, as judged by electron microscopy. Optical diffraction analysis reveals that these purified actin filaments have helical parameters very similar to those of muscle actin. Furthermore, the properties of the purified actin with regard to activation of myosin ATPase are similar to those of actin from other cell types. The possibility that actin is maintained in a nonfilamentous form on the inner surface of the unfertilized egg plasma membrane and is induced to assemble upon fertilization is discussed.

The fine structure of Sphaerotilus nutans

1973 ◽  
Vol 19 (3) ◽  
pp. 309-313 ◽  
Author(s):  
Judith F. M. Hoeniger ◽  
H.-D. Tauschel ◽  
J. L. Stokes
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Lateral Position ◽  
Thin Sections ◽  
Liquid Cultures ◽  
Sphaerotilus Natans ◽  
Stationary Liquid ◽  
Basal Disk ◽  
Polar Organelle

Sphaerotilus natans developed sheathed filaments in stationary liquid cultures and motile swarm cells in shaken ones. Electron microscopy of negatively stained preparations and thin sections showed that the sheath consists of fibrils. When the filaments were grown in broth with glucose added, the sheath was much thicker and the cells were packed with granules of poly-β-hydroxybutyrate.Swarm cells possess a subpolar tuft of 10 to 30 flagella and a polar organelle which is usually inserted in a lateral position and believed to be ribbon-shaped. The polar organelle consists of an inner layer joined by spokes to an accentuated plasma membrane. The flagellar hook terminates in a basal disk, consisting of two rings, which is connected by a central rod to a second basal disk.

scholarly journals OBSERVATIONS ON THE FINE STRUCTURE OF THE MACRONUCLEUS OF TOKOPHRYA INFUSIONUM

1955 ◽  
Vol 1 (5) ◽  
pp. 421-428 ◽  
Author(s):  
Maria A. Rudzinska ◽  
Keith R. Porter
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Cross Sections ◽  
Regular Structure ◽  
Metaphase Chromosomes ◽  
Thin Sections ◽  
Significant Aspect ◽  
Parallel Lines ◽  
Chromatin Material ◽  
First Time

The macronucleus in Tokophrya infusionum is composed of numerous Feulgen-positive chromatin bodies (about 0.5 µ in diameter) which appear in thin sections as a dense spongework, homogeneous throughout. The same appearance characterizes metaphase chromosomes of higher forms. Some chromatin bodies of the macronucleus were found to possess a highly organized structure in certain old organisms. This structure appears in cross-sections as a honeycomb and in longitudinal sections as parallel lines about 120 A in diameter evenly spaced (about 230 A). As far as is known this is the first time a regular structure has been found in bodies of chromosomal character at the dimensional level presently explored by electron microscopy. The demonstration that OsO4 can preserve order in chromatin material is another significant aspect of these findings.

scholarly journals Further Observations on the Fine Structure of Chrysochromulina Ericina Parke & Manton

1961 ◽  
Vol 41 (1) ◽  
pp. 145-155 ◽  
Author(s):  
I. Manton ◽  
G. F. Leedale
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Cell Surface ◽  
Light Microscopy ◽  
Flat Plate ◽  
Outer Layer ◽  
Living Cells ◽  
Layered Plates ◽  
Thin Sections ◽  
Micro Anatomy

C. ericina Parke & Manton has been re-investigated to add salient features of micro-anatomy from the electron microscopy of thin sections and also to add photographs of living cells taken with anoptral contrast light microscopy.The most important new observations concern the scales which are shown to be essentially two-layered plates in which the layers in the very large spined scales have become separated except at their edges, with the outer layer greatly hypertrophied to produce a hollow spine with a flared base closed at the bottom by a flat plate. The patterns of external marking on the two layers are very similar in both plate-scales and spines in this species and the orientation of both with respect to the cell surface has been demonstrated by a section of the scales in situ.

Simplified procedures for releasing and concentrating microorganisms from soil for transmission electron microscopy viewing as thin-sectioned and frozen-etched preparations

1975 ◽  
Vol 21 (3) ◽  
pp. 252-262 ◽  
Author(s):  
D. L. Balkwill ◽  
D. P. Labeda ◽  
L. E. Casida Jr.
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Types ◽  
Soil Slurry ◽  
Thin Sections ◽  
Choice Of Procedure ◽  
Transmission Electron ◽  
Cell Release ◽  
Simplified Procedures ◽  
Simplified Procedure

A simplified procedure is presented for releasing and concentrating indigenous microbial cells from soil for viewing by transmission electron microscopy as thin sections or replicas of frozen-etched preparations. This procedure is compared with two others reported earlier, and their relative merits are discussed as concerns the choice of procedure for the cellular information desired from the soil. Freeze-etching showed that the cell types and size distributions for cells which have been released and concentrated from soil are in general agreement with those for cells in a crude soil slurry in which no attempt to release and concentrate cells was made. Microcolonies were present both in the crude slurry and in the discard soil debris centrifugation pellets from the cell release and concentration procedures. In contrast to the historic assumptions, these microcolonies, as well as some individual cells embedded in soil debris could not be broken up and (or) dislodged so that they would be washed from the soil. The relative numbers of these cells remaining with the soil debris, however, could not be quantitated in the present study.

scholarly journals The Fine Structure of the Wheat Scutellum During Germination

1972 ◽  
Vol 25 (3) ◽  
pp. 469 ◽  
Author(s):  
JG Swift ◽  
TP O'brien
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Epithelial Cells ◽  
Light And Electron Microscopy ◽  
Cell Types ◽  
Wall Material ◽  
Cytological Evidence ◽  
Starch Grains ◽  
Parenchyma Cells ◽  
Cytological Changes

The cytological changes that take place in the scutellar epithelium and parenchyma during the first 5 days of germination are described by light and electron microscopy. Within 6 hr small starch grains appear in the plastids of both cell types and the size and number of starch grains increase gradually as germination proceeds. Later in germination starch disappears again from the plastids in the epithelial cells, but large starch grains still remain in the parenchyma cells. The reserves of the protein bodies are hydrolysed and the residual vacuoles undergo extensive coales-cence. Modifications in the appearance of the wall material of the epithelial cells as these cells elongate are illustrated and possible functional bases for these changes are suggested. The cells of the scutellar epithelium show no cytological evidence for their known functions of diastase secretion and nutrient absorption.

High Voltage Electron Microscopy of Muscle

1969 ◽  
Vol 27 ◽  
pp. 96-97
Author(s):  
Robert V. Rice ◽  
J. S. Lally
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
High Voltage ◽  
Striated Muscle ◽  
High Voltage Electron Microscopy ◽  
Thin Sections ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Cell Biol ◽  
Adjacent Structures

Several structures have been proposed to account for the appearance of Z and M-lines seen in thin sections of striated muscle. The high penetrating power of 800,000 to 1,000,000 volt electrons coupled with stereology offers a unique opportunity to resolve the complicated fine structure of Z and M-lines. In addition use has been made of the recently developed extraction and reconstitution of Z and M-lines (Stromer, Hartshorne, Mueller, and Rice, J. Cell Biol., 40, 167, 1969). Removal of portions of these structures helps to eliminate confusion due to adjacent structures.

Sign in / Sign up

Export Citation Format

Share Document