A Differential Centrifugation Procedure for Obtaining Unstretched Metaphase Chromosomes from Higher Plants for Transmission Electron Microscopy

1977 ◽  
Vol 35 ◽  
pp. 402-403 ◽  
Author(s):  
Philip S. Woods ◽  
Jack Van't Hof ◽  
Myron C. Ledbetter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Higher Plants ◽  
Plant Root ◽  
Root Tip ◽  
Natural State ◽  
Differential Centrifugation ◽  
Metaphase Chromosomes ◽  
Transmission Electron ◽  
Water Spreading

Metaphase chromosomes prepared as whole mounts for transmission electron microscopy have been studied by many workers using a variety of methods(1,2,3, 4). While satisfactory for some purposes these methods usually result in distortions which complicate interpretation of chromosome fine structure. In addition, most procedures were adapted for animal chromosomes and were inappropriate for plants in which cell walls present a barrier to isolation. Recently, Wolfe and Martin(5) used a pressing procedure devised by McLeish(6) to obtain plant root tip chromosomes and used this in combination with the water spreading method of Gall(3). Their electron micrographs, though unique in showing plant chromosomes essentially for the first time, nevertheless showed chromosomal distortions typical of water spreading. Chromosomes in the nearly natural state can be obtained by modifying Wolfe and Martin's procedure to the extent of replacing surface spreading with differential centrifugation of the broken-cell suspension.

Phagocytosis of tumor cells by activated liver macrophages.

1987 ◽  
Vol 45 ◽  
pp. 720-721
Author(s):  
Arthur J. Wasserman ◽  
Carol R. Gardner ◽  
Debra L. Laskin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Differential Centrifugation ◽  
Transmission Electron ◽  
Collagenase Perfusion ◽  
Rat Livers ◽  
Tissue Origin ◽  
Tumor Cell Killing

Kupffer cells (KC) are fixed macrophages (Mø) that line the hepatic sinusoids. In response to antigenic or tumor cell challange KC become “activated” and display enhanced biochemical and functional reactivity including increased chemotaxis, phagocytosis, oxidative metabolism and tumor cell killing. We have observed that lipopolysaccharide (LPS)-activated liver Mø phagocytize certain tumor cell targets depending on their tissue origin. This was unusual as Mø typically do not kill tumor targets by phagocytosis. The present studies were designed to study the mechanism involved in liver mø mediated phagocytosis of tumor targets.Mø were isolated from rat livers 48 hr following treatment with LPS (5mg/kg IV) by combined pronase/collagenase perfusion, selective digestion and differential centrifugation. Mø were coincubated on glass coverslips or slides with tumor cells for 48 hr. For both scanning and transmission electron microscopy (SEM,TEM), cells were fixed for 60 min at 4°C in 236 glutaraldehyde buffered by 0.1M cacodylate containing 0.1M sucrose and 1.5mM CaCl2 (pH 7.4).

Centromere structure and chromosome number in mitosis of the colourless phytoflagellate Polytoma papillatum (Chlorophyceae, Volvocales, Chlamydomonadaceae)

Genome ◽  
1995 ◽  
Vol 38 (6) ◽  
pp. 1249-1254 ◽  
Author(s):  
Klaus Werner Wolf
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chromosome Number ◽  
Higher Plants ◽  
Attachment Site ◽  
Dense Layer ◽  
Mitotic Metaphase ◽  
Serial Sections ◽  
Transmission Electron ◽  
Alternative Approach

Centromere structure is described in mitosis of the unicellular biflagellate alga Polytoma papillatum using transmission electron microscopy. The kinetochores are five-layered elements at the poleward surface of the chromosomes. The five layers consist of three dense plates interspersed by two transparent zones. The polemost dense layer serves as the attachment site for kinetochore microtubules and the innermost dense layer is intimately associated with the chromatin. The five-layered organization of the kinetochore in the alga is unusual. In animals, three-layered kinetochores are the rule. This type has also been found in some algae, while higher plants do not possess striated kinetochores. An attempt was made to determine the chromosome number of P. papillatum. Individual chromosomes could not be recognized with confidence, since there were numerous lateral contacts between the chromosomes throughout mitosis. An alternative approach, however, was successful. Counting the kinetochores in serial sections through mitotic metaphase and anaphase plates revealed a number of 15 chromosomes.Key words: anaphase, kinetochore, metaphase, microtubule.

Ultrastructure of sperm development in the genus Ditylenchus (Nematoda: Anguinidae)

Nematology ◽  
2015 ◽  
Vol 17 (3) ◽  
pp. 313-324 ◽  
Author(s):  
Dieter Slos ◽  
Pooria Ensafi ◽  
Myriam Claeys ◽  
Vladimir V. Yushin ◽  
Wilfrida Decraemer ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Outer Membrane ◽  
Higher Plants ◽  
Transmission Electron ◽  
Sperm Development ◽  
Ditylenchus Dipsaci ◽  
Mature Spermatozoa ◽  
Formation Of Complexes

Spermatogenesis in Ditylenchus arachis and D. dipsaci was studied using transmission electron microscopy. Spermatogenesis includes the formation of complexes of fibrous bodies (FB) and membranous organelles (MO) in the spermatocytes, which dissociate in separated MO and FB in the spermatids. Immature spermatozoa are unpolarised cells with separate FB and MO. Mature spermatozoa are arranged in chains. Ditylenchus dipsaci is unique in having MO that have already fused with the outer membrane in immature spermatozoa and have mature spermatozoa in the male testis, proving that not only insemination plays a role in spermiogenesis. Contrary to what has been described before, spermatogenesis in Ditylenchus, and other early diverging Tylenchomorpha, follow the typical ‘rhabditid’ pattern, while the absence of MO within Tylenchomorpha appears to be an apomorphic trait for the molecular defined clade of tylenchids that exclusively parasitise higher plants. This confirms the value of traits related to spermatogenesis in nematode phylogeny.

scholarly journals Immunogold-labelling localization of chlorophyllase at different developmental stages of Pachira macrocarpa leaves

2021 ◽  
Author(s):  
Tzan-Chain Lee ◽  
Kuan-Hung Lin ◽  
Chang-Chang Chen ◽  
Tin-Han Shih ◽  
Meng-Yuan Huang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Wall ◽  
Plasma Membrane ◽  
Thylakoid Membrane ◽  
Developmental Stages ◽  
Higher Plants ◽  
Plant Cells ◽  
Immunogold Labelling ◽  
Transmission Electron

Abstract Background: Chlorophyllases (Chlases) are housekeeping proteins in plant cells. The dephytylating enzymes can catalyze chlorophyll (Chl) to form chlorophyllide, but the distribution of Chlases in plant cells is still an interesting debate. In this study, antibody of PmCLH2 was made and used by immunogold-labelling technique to detect the location of Chlase of Pachira macrocarpa (Pm) leaves at four developmental stages, including young, mature, yellowing, and senesced stages. Results: The transmission electron microscopy results show that Chlases were comprehensively found in portions of chloroplast, such as the inner membrane of the envelope, grana, and the thylakoid membrane of the chloroplast, cytosol, and vacuoles at young, mature, and yellowing stages of Pm leaves, but not in the cell wall, plasma membrane, mitochondria, and nucleus. Conclusions: PmChlases were mainly detected in vacuoles at the senescent stage, but a few were found in the chloroplasts. A pathway is proposed to explain the birth and death of Chl, Chlase, and chloroplasts in higher plants.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

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).

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