scholarly journals SPATIAL PATTERNS OF THREADLIKE ELEMENTS IN THE AXOPLASM OF THE GIANT NERVE FIBER OF THE SQUID (LOLIGO PEALII L.) AS DISCLOSED BY DIFFERENTIAL INTERFERENCE MICROSCOPY AND BY ELECTRON MICROSCOPY

1969 ◽  
Vol 43 (3) ◽  
pp. 456-479 ◽  
Author(s):  
J. Metuzals ◽  
C. S. Izzard
Keyword(s):  
Electron Microscopy ◽  
Nerve Fiber ◽  
Three Dimensional ◽  
Interference Microscopy ◽  
Network Configuration ◽  
Normal Functioning ◽  
Interference Microscope ◽  
Dimensional Network ◽  
Differential Interference Microscope

The giant nerve fiber of the squid (Loligo pealii L.) has been investigated in situ, and in fresh and fixed preparations, by differential interference microscopy and electron microscopy. A continuous, three-dimensional network, composed of threadlike elements, was disclosed in the axoplasm. The threadlike elements in the axoplasm are twisted as a whole into a steep, right-handed helix. In a peripheral ectoplasmic region, the elements are more parallel to one another and more densely packed than in a central endoplasmic core. The threadlike elements can be resolved into a hierarchy of decreasing order of size. Successive levels of the hierarchy are formed by the association of smaller elements into larger ones. The following levels in the hierarchy of network elements have been distinguished: 1–3-µ-wide threads, 0.1–0.35-µ-wide strands, and 70–250-A-wide unit-filament strands. The differential interference microscope selects, from the network, threads oriented at a specific angle to the long axis of the axon. The specific angle depends upon the orientation of the long axis of the axon relative to the direction of shear. It is postulated that the network configuration is expressed in the solid-state properties of the axoplasm essential for the normal functioning of the nerve fiber.

Scanning Electron Microscopy and Electron Microprobe Analysis of Malignant Cell Cultures

1968 ◽  
Vol 26 ◽  
pp. 164-165
Author(s):  
R. I. Johnsson-Hegyeli ◽  
A. F. Hegyeli ◽  
D. K. Landstrom ◽  
W. C. Lane
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Cultures ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Three Dimensional ◽  
Malignant Cell ◽  
Interference Microscopy ◽  
Scanning Electron

Last year we reported on the use of reflected light interference microscopy (RLIM) for the direct color photography of the surfaces of living normal and malignant cell cultures without the use of replicas, fixatives, or stains. The surface topography of living cells was found to follow underlying cellular structures such as nuceloli, nuclear membranes, and cytoplasmic organelles, making possible the study of their three-dimensional relationships in time. The technique makes possible the direct examination of cells grown on opaque as well as transparent surfaces. The successful in situ electron microprobe analysis of the elemental composition and distribution within single tissue culture cells was also reported.This paper deals with the parallel and combined use of scanning electron microscopy (SEM) and the two previous techniques in a study of living and fixed cancer cells. All three studies can be carried out consecutively on the same experimental specimens without disturbing the cells or their structural relationships to each other and the surface on which they are grown. KB carcinoma cells were grown on glass coverslips in closed Leighto tubes as previously described. The cultures were photographed alive by means of RLIM, then fixed with a fixative modified from Sabatini, et al (1963).

scholarly journals A microscopic approach to investigate bacteria under in situ conditions in sea-ice samples

2001 ◽  
Vol 33 ◽  
pp. 304-310 ◽  
Author(s):  
Karen Junge ◽  
Christopher Krembs ◽  
Jody Deming ◽  
Aaron Stierle ◽  
Hajo Eicken
Keyword(s):  
Sea Ice ◽  
Pore Space ◽  
Three Dimensional ◽  
Epifluorescence Microscopy ◽  
Microbial Populations ◽  
Microbial Life ◽  
Dimensional Network ◽  
In Situ Conditions ◽  
Fluorescent Stain

AbstractMicrobial populations and activity within sea ice have been well described based on bulk measurements from melted sea-ice samples. However, melting destroys the micro-environments within the ice matrix and does not allow for examination of microbial populations at a spatial scale relevant to the organism. Here, we describe the development of a new method allowing for microscopic observations of bacteria localized within the three-dimensional network of brine inclusions in sea ice under in situ conditions. Conventional bacterial staining procedures, using the DNA-specific fluorescent stain DAPI, epifluorescence microscopy and image analysis, were adapted to examine bacteria and their associations with various surfaces within microtomed sections of sea ice at temperatures from −2° to −15°C. The utility and sensitivity of the method were demonstrated by analyzing artificial sea-ice preparations of decimal dilutions of a known bacterial culture. When applied to natural, particle-rich sea ice, the method allowed distinction between bacteria and particles at high magnification. At lower magnifications, observations of bacteria could be combined with those of other organisms and with morphology and particle content of the pore space. The method described here may ultimately aid in discerning constraints on microbial life at extremely low temperatures.

In-Situ Formation and Coating of Cordierite Whiskers on Cordierite Based Honeycomb Support

2006 ◽  
Vol 317-318 ◽  
pp. 701-704
Author(s):  
Daniel Doni Jayaseelan ◽  
Shunkichi Ueno ◽  
Hideki Kita ◽  
Naoki Kondo ◽  
Tatsuki Ohji
Keyword(s):  
Three Dimensional ◽  
Sem Analysis ◽  
In Situ Method ◽  
Dimensional Network ◽  
In Situ Formation ◽  
Cordierite Honeycomb ◽  
Complete Formation ◽  
Aqueous Slurry

In this work, cordierite whiskers were successfully coated on cordierite honeycomb support by in-situ method. Whisker coating was performed on walls of the pore channels of cordierite support from aqueous slurry. Sintering was carried out at 1300 °C for 4 hours. XRD measurements revealed a complete formation of cordierite phase, no traces of other phases were identified. A well adherence of coating on the support was identified from the microstructure. SEM analysis also revealed the formation of three-dimensional network of cordierite whiskers with open pores between them on the cordierite support.

scholarly journals Three-dimensional electron microscopy of ribosomal chromatin in two higher plants: a cytochemical, immunocytochemical, and in situ hybridization approach.

1991 ◽  
Vol 39 (11) ◽  
pp. 1495-1506 ◽  
Author(s):  
P M Motte ◽  
R Loppes ◽  
M Menager ◽  
R Deltour
Keyword(s):  
Electron Microscopy ◽  
In Situ Hybridization ◽  
Spatial Organization ◽  
Higher Plants ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Thin Sections ◽  
Cytoplasmic Dna ◽  
Immunocytochemical Techniques

We report the 3-D arrangement of DNA within the nucleolar subcomponents from two evolutionary distant higher plants, Zea mays and Sinapis alba. These species are particularly convenient to study the spatial organization of plant intranucleolar DNA, since their nucleoli have been previously reconstructed in 3-D from serial ultra-thin sections. We used the osmium ammine-B complex (a specific DNA stain) on thick sections of Lowicryl-embedded root fragments. Immunocytochemical techniques using anti-DNA antibodies and rDNA/rDNA in situ hybridization were also applied on ultra-thin sections. We showed on tilted images that the OA-B stains DNA throughout the whole thickness of the section. In addition, very low quantities of cytoplasmic DNA were stained by this complex, which is now the best DNA stain used in electron microscopy. Within the nucleoli the DNA was localized in the fibrillar centers, where large clumps of dense chromatin were also visible. In the two plant species intranucleolar chromatin forms a complex network with strands partially linked to chromosomal nucleolar-organizing regions identified by in situ hybridization. This study describes for the first time the spatial arrangement of the intranucleolar chromatin in nucleoli of higher plants using high-resolution techniques.

scholarly journals In situ structure of virus capsids within cell nuclei by correlative light and cryo-electron tomography

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Swetha Vijayakrishnan ◽  
Marion McElwee ◽  
Colin Loney ◽  
Frazer Rixon ◽  
David Bhella
Keyword(s):  
Electron Microscopy ◽  
Structure Determination ◽  
Electron Tomography ◽  
3D Structure ◽  
Three Dimensional ◽  
Cell Nuclei ◽  
Nuclear Egress ◽  
Virus Capsids ◽  
Cryo Electron Tomography

Abstract Cryo electron microscopy (cryo-EM), a key method for structure determination involves imaging purified material embedded in vitreous ice. Images are then computationally processed to obtain three-dimensional structures approaching atomic resolution. There is increasing interest in extending structural studies by cryo-EM into the cell, where biological structures and processes may be imaged in context. The limited penetrating power of electrons prevents imaging of thick specimens (> 500 nm) however. Cryo-sectioning methods employed to overcome this are technically challenging, subject to artefacts or involve specialised and costly equipment. Here we describe the first structure of herpesvirus capsids determined by sub-tomogram averaging from nuclei of eukaryotic cells, achieved by cryo-electron tomography (cryo-ET) of re-vitrified cell sections prepared using the Tokuyasu method. Our reconstructions confirm that the capsid associated tegument complex is present on capsids prior to nuclear egress. We demonstrate that this method is suited to both 3D structure determination and correlative light/electron microscopy, thus expanding the scope of cryogenic cellular imaging.

scholarly journals In Situ Transmission Electron Microscopy Imaging of Electromigration in Platinum Nanowires

2013 ◽  
Vol 19 (S5) ◽  
pp. 43-48 ◽  
Author(s):  
Maria Rudneva ◽  
Bo Gao ◽  
Ferry Prins ◽  
Qiang Xu ◽  
Herre S.J. van der Zant ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Feedback Control ◽  
Three Dimensional ◽  
Dark Field ◽  
Control Mode ◽  
Microscopy Imaging ◽  
Platinum Nanowires ◽  
Transmission Electron

AbstractIn situ transmission electron microscopy was performed on the electromigration in platinum (Pt) nanowires (14 nm thick, 200 nm wide, and 300 nm long) with and without feedback control. Using the feedback control mode, symmetric electrodes are obtained and the gap usually forms at the center of the Pt nanowire. Without feedback control, asymmetric electrodes are formed, and the gap can occur at any position along the wire. The three-dimensional gap geometries of the electrodes in the Pt nanowire were determined using high-angle annular dark-field scanning transmission electron microscopy; the thickness of the nanowire is reduced from 14 nm to only a few atoms at the edge with a gap of about 5–10 nm.

scholarly journals Subaxolemmal filamentous network in the giant nerve fiber of the squid (Loligo pealei L.) and its possible role in excitability.

1978 ◽  
Vol 78 (2) ◽  
pp. 597-621 ◽  
Author(s):  
J Metuzals ◽  
I Tasaki
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nerve Fiber ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Three Dimensional ◽  
Polarized Light ◽  
Thin Sections ◽  
Loligo Pealei ◽  
Scanning Electron

A new technique utilizing the squid giant nerve fiber has been developed which permits direct examination of the inner face of the axolemma by scanning electron microscopy. The axoplasm was removed sequentially in a 15-mm long segment of the fiber by intracellular perfusion with a solution of KF, KCl, Ca++-containing seawater, or with pronase. The action potential of the fibers was monitored during these treatments. After brief prefixation in 1% paraformaldehyde and 1% glutaraldehyde, the perfused segment was opened by a lne could be related to information on the detailed morphology of the cytoplasmic face of the axolemma and the ectoplasm. The results obtained by scanning electron microscopy were further substantiated by transmission electron microscopy of thin sections. In addition, living axons were studied with polarized light during axoplasm removal, and the identification of actin by heavy meromyosin labeling and sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis was accomplished. These observations demonstrate that a three-dimensional network of interwoven filaments, consisting partly of an actinlike protein, is firmly attached to the axolemma. The axoplasmic face of fibers in which the filaments have been removed partially after perfusion with pronase displays smooth membranous blebs and large profiles which sppose the axolemma. In fibers where the excitability has been suppressed by pronase perfusion, approximately one-third of the inner face of the axolemma in the perfusion zone is free of filaments. It is hypothesized that the attachment of axoplasm filaments to the axolemma may have a role in the maintenance of the normal morphology of the axolemma, and, thus, in some aspect of excitability.

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