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 SPERMATOGENESIS IN ANIMALS AS REVEALED BY ELECTRON MICROSCOPY

1957 ◽  
Vol 3 (5) ◽  
pp. 663-668 ◽  
Author(s):  
G. Yasuzumi ◽  
Hiroshi Ishida
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Cross Sections ◽  
Fibrillar Structure ◽  
Submicroscopic Structure ◽  
Tissue Sections ◽  
Parallel Lines ◽  
Early Spermatid ◽  
Spermatid Nucleus ◽  
Honeycomb Pattern

The submicroscopic structure of the maturing spermatid nucleus of the grasshopper, Gelastorrhinus bicoler de Haan, has been studied in thin tissue sections by electron microscopy. In the early spermatid the nucleus appears dense with no clearly resolvable fine structure. In the advanced spermatid with a conical-shaped nucleus, the karyoplasm begins to show a fibrillar structure. At subsequent stages, the elongated spermatid nucleus displays in cross-sections a hexagonal honeycomb pattern and in longitudinal sections an array of parallel lines, 70 A in diameter and spaced 100 to 220 A apart. As differentiation of the spermatid proceeds further, the space between the lines becomes narrower and narrower until it can no longer be resolved.

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).

Video Graphics and High-Voltage Electron Microscopy For Analysis of Microtubule Distributions In Fixed Cells

1990 ◽  
Vol 48 (1) ◽  
pp. 524-525
Author(s):  
Richard Mcintosh ◽  
David Mastronarde ◽  
Kent McDonald ◽  
Rubai Ding
Keyword(s):  
Electron Microscopy ◽  
Cross Sections ◽  
Cell Shape ◽  
Video Camera ◽  
Computer Memory ◽  
High Voltage Electron Microscopy ◽  
Thin Sections ◽  
Voltage Electron ◽  
Morphogenetic Event ◽  
Set Of Points

Microtubules (MTs) are cytoplasmic polymers whose dynamics have an influence on cell shape and motility. MTs influence cell behavior both through their growth and disassembly and through the binding of enzymes to their surfaces. In either case, the positions of the MTs change over time as cells grow and develop. We are working on methods to determine where MTs are at different times during either the cell cycle or a morphogenetic event, using thin and thick sections for electron microscopy and computer graphics to model MT distributions.One approach is to track MTs through serial thin sections cut transverse to the MT axis. This work uses a video camera to digitize electron micrographs of cross sections through a MT system and create image files in computer memory. These are aligned and corrected for relative distortions by using the positions of 8 - 10 MTs on adjacent sections to define a general linear transformation that will align and warp adjacent images to an optimum fit. Two hundred MT images are then used to calculate an “average MT”, and this is cross-correlated with each micrograph in the serial set to locate points likely to correspond to MT centers. This set of points is refined through a discriminate analysis that explores each cross correlogram in the neighborhood of every point with a high correlation score.

scholarly journals PROVENANCE OF PINDOS FORELAND FLYSCH DEPOSITS USING SCANNING ELECTRON MICROSCOPY AND MICROANALYSIS

2004 ◽  
Vol 36 (1) ◽  
pp. 607 ◽  
Author(s):  
I. Vakalas ◽  
G. Ananiadis ◽  
A. Zelilidis ◽  
N. Kontopoulos ◽  
B. Tsikouras
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cross Sections ◽  
Thin Sections ◽  
Source Areas ◽  
Probable Source ◽  
Pelagonian Zone ◽  
Source Materials ◽  
Scanning Electron

A number of polished thin sections from two cross sections within the Pindos foreland deposits were petrographically examined while microanalyses on certain minerals were carried out. Chemistry of these minerals is compared to analogous phases occurring in several formations in the neighbourhood of the studied areas which can stand as source areas. Our results reveal that the most probable source materials include the Pindos, Koziakas (and probably and Vourinos) ophiolite complexes, as well as metamorphic sequences of the Pelagonian Zone

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.

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 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.

scholarly journals An Effective Method of Preparing Sections of Bacillus polymyxa Sporangia and Spores for Electron Microscopy

1960 ◽  
Vol 7 (2) ◽  
pp. 373-376 ◽  
Author(s):  
Pauline E. Holbert
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Micrographs ◽  
Epoxy Resins ◽  
Bacillus Polymyxa ◽  
Thin Sections ◽  
Similar Images ◽  
Embedding Medium ◽  
First Time ◽  
Diamond Knife

Bacillus polymyxa sporangia and spores were prepared for examination in the electron microscope by methods whose critical features were apparently: judicious use of vacuum, to encourage complete penetration of the embedding medium; the use of epoxy resins as embedding media; and cutting of the thin sections with a diamond knife. Electron micrographs of material prepared in this manner exhibit undeformed sporangial sections. Some of the structures revealed have been shown before, though perhaps less distinctly; other structures are revealed here for the first time. While this single study does not pretend to elucidate all the complexities of sporulation in bacteria, these and similar images should make this possible, and some mention of the preparatory techniques that lead to them seems advisable at this time.

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.

scholarly journals THE FINE STRUCTURE OF THE NUCLEOLUS DURING MITOSIS IN THE GRASSHOPPER NEUROBLAST CELL

1965 ◽  
Vol 24 (3) ◽  
pp. 349-368 ◽  
Author(s):  
Barbara J. Stevens
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Light Microscope ◽  
Light And Electron Microscopy ◽  
Peripheral Zone ◽  
Structural Components ◽  
Thin Sections ◽  
Nucleolar Material ◽  
Central Regions ◽  
Homogeneous Background

The behavior of the nucleolus during mitosis was studied by electron microscopy in neuroblast cells of the grasshopper embryo, Chortophaga viridifasciata. Living neuroblast cells were observed in the light microscope, and their mitotic stages were identified and recorded. The cells were fixed and embedded; alternate thick and thin sections were made for light and electron microscopy. The interphase nucleolus consists of two fine structural components arranged in separate zones. Concentrations of 150 A granules form a dense peripheral zone, while the central regions are composed of a homogeneous background substance. Observations show that nucleolar dissolution in prophase occurs in two steps with a preliminary loss of the background substance followed by a dispersal of the granules. Nucleolar material reappears at anaphase as small clumps or layers at the chromosome surfaces. These later form into definite bodies, which disappear as the nucleolus grows in telophase. Evidence suggests both a collecting and a synthesizing role for the nucleolus-associated chromatin. The final, mature nucleolar form is produced by a rearrangement of the fine structural components and an increase in their mass.

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