Ultrastructural evidence for the existence of actinorhizal symbioses in the late Pleistocene

1980 ◽  
Vol 58 (15) ◽  
pp. 1612-1620 ◽  
Author(s):  
Dwight Baker ◽  
Norton G. Miller
Keyword(s):  
Electron Microscopy ◽  
Root Nodule ◽  
Root Nodules ◽  
Eastern North America ◽  
Independent Evidence ◽  
Qualitative And Quantitative ◽  
Ultrastructural Evidence ◽  
Shepherdia Canadensis ◽  
Nodule Endophytes ◽  
Scanning Electron

Macrofossil actinorhizal root nodules discovered in sediments about 11 500 radiocarbon years old in northern Vermont, U.S.A., were studied by scanning electron microscopy. Evidence of an endophytic microsymbiont was observed within the cortex of the fossil nodules. A comparative study as undertaken using root nodules from species of Alnus, Dryas, Elaeagnus, Myrica, Shepherdia, and Vicia native to eastern North America in an effort to determine the identity of the fossils. From qualitative and quantitative differences observed among the root nodule endophytes, it was concluded that the fossil nodules contained actinomycetes morphologically similar to those of extant Elaeagnaceae. The fossils are probably from plants of Elaeagnus commutata and (or) Shepherdia canadensis based on independent evidence of the representation of these species in the plant macrofossil assemblage.

Ultrastructure of the Alnus crispa var. mollis Fern. root nodule endophyte

1975 ◽  
Vol 21 (7) ◽  
pp. 1058-1080 ◽  
Author(s):  
Maurice Lalonde ◽  
Roger Knowles
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Root Nodule ◽  
Root Nodules ◽  
Host Cells ◽  
Alnus Crispa ◽  
Transmission Electron ◽  
Host Cell Wall ◽  
Capsular Material ◽  
Nodule Endophytes

Nitrogen-fixing, field-obtained root nodules of the silky green alder were studied by transmission electron microscopy. The nodule endophyte exhibited a prokaryotic cytology and was present in two forms: the hypha (0.3–1.0 μm), which was branched and septate, and the vesicle (3–5 μm), which was also septate and developed at the parental hypha tip. Bacteria-like cells, previously observed in light microscopy studies, were not seen in the present work. The actinomycete-like endophyte penetrated through the host cell wall and became enveloped by a capsular material (0.1 μm), the whole being enclosed by host membranes. In some host cells, the endophyte appeared to lyse and become a mass of shrunken debris. The fine structure of the Alnus crispa var. mollis root nodule endophyte was found to be similar to that of other non-leguminous root nodule endophytes.

Qualitative and Quantitative Analysis of Boron Content Precipitates by FEG-SEM and EDS Methods

2010 ◽  
Vol 659 ◽  
pp. 295-300 ◽  
Author(s):  
Éva Dénes ◽  
Attila Lajos Tóth ◽  
Fábián Enikő-Réka
Keyword(s):  
Electron Microscopy ◽  
Boron Content ◽  
Fish Scale ◽  
Type Number ◽  
Low Carbon ◽  
Qualitative And Quantitative Analysis ◽  
Free Diffusion ◽  
Qualitative And Quantitative ◽  
Scale Failure ◽  
Scanning Electron

The effect of the boron in steels is widely known as an element enhancing hardenability, but its role can also be related to the enamelability of steels. While the improvement of the hardenability is due to the solute boron, in the case of enameling grade steels the boron should be kept in form of precipitates 1. The hydrogen accumulated during processing and enameling diffuses to the metal/enamel interface and lead to the formation of the so called fish-scale failure. To prevent this it is needed an adequate type, number and dimension of precipitates which act as hydrogen traps hinder the free diffusion of the hydrogen in steel. The paper deals with the possibilities of investigation by scanning electron microscopy of the boron containing precipitates in the low carbon Al-killed steels apt for two side enamelling.

Spheroplasts of Rhizobium japonicum

1984 ◽  
Vol 30 (3) ◽  
pp. 415-419 ◽  
Author(s):  
James O. Berry ◽  
Alan G. Atherly
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Root Nodules ◽  
Rhizobium Japonicum ◽  
Soybean Root ◽  
Scanning Electron

Speroplasts of Rhizobium japonicum strains 61A76, USDA 31, and 110 were prepared by culturing cells in the presence of glycine, followed by treatment with lysozyme. The cells were examined by scanning electron microscopy before, during, and after becoming spheroplasts and found to be morphologically similar to the bacteroid forms found in soybean root nodules. Some similarities of spheroplast and bacteroid formation are discussed.

Analysis of Blockage in Heat-Exchanger of Crude Oil Stabilizer Station

2013 ◽  
Vol 864-867 ◽  
pp. 1213-1218
Author(s):  
Bo Zhang ◽  
Lei Zhang ◽  
Zhi Bo Tong ◽  
Xin Gang Wang ◽  
Chun Li Liu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Heat Exchanger ◽  
Chemical Analysis ◽  
Crude Oil ◽  
The Other ◽  
Qualitative And Quantitative ◽  
Xrd Diffraction ◽  
Inorganic Substances ◽  
Scanning Electron

The most shortage of heat-exchanger in crude oil stabilizer station was scaling. The forming of blockage has been confirmed, by the methods of chemical analysis, XRD diffraction and scanning electron microscopy (SEM) to analyse the qualitative and quantitative of it. The blockage is due to the impurity in oil. On one hand, the inorganic substances, mainly Si4+ and Al3+, adhere to the wall by chemical reaction. On the other hand, heavy oil, like asphaltenes, is eluted from flow and exacerbated the adsorption force. Thus, a group of organic and inorganic clogs has formed, which cause the scaling of heat-exchanger unit.

Correlative Fractography: Combining Scanning Electron Microscopy and Light Microscopes for Qualitative and Quantitative Analysis of Fracture Surfaces

2013 ◽  
Vol 19 (2) ◽  
pp. 496-500 ◽  
Author(s):  
Luis Rogerio de Oliveira Hein ◽  
José Alberto de Oliveira ◽  
Kamila Amato de Campos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Quantitative Analysis ◽  
New Method ◽  
Fracture Mechanisms ◽  
Stereo Pair ◽  
Qualitative And Quantitative Analysis ◽  
Qualitative And Quantitative ◽  
Fracture Surfaces ◽  
Scanning Electron

AbstractCorrelative fractography is a new expression proposed here to describe a new method for the association between scanning electron microscopy (SEM) and light microscopy (LM) for the qualitative and quantitative analysis of fracture surfaces. This article presents a new method involving the fusion of one elevation map obtained by extended depth from focus reconstruction from LM with exactly the same area by SEM and associated techniques, as X-ray mapping. The true topographic information is perfectly associated to local fracture mechanisms with this new technique, presented here as an alternative to stereo-pair reconstruction for the investigation of fractured components. The great advantage of this technique resides in the possibility of combining any imaging methods associated with LM and SEM for the same observed field from fracture surface.

Current Applications and Methods of Microvascular Corrosion Casting: A Review

1998 ◽  
Vol 4 (S2) ◽  
pp. 908-909
Author(s):  
A. Lametschwandtner ◽  
H. Aichhorn ◽  
B. Minnich
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Great Depth ◽  
Corrosion Casting ◽  
Corrosion Casts ◽  
Depth Of Focus ◽  
Subsequent Removal ◽  
Blood Capillaries ◽  
Qualitative And Quantitative ◽  
Scanning Electron

Casting of hollow spaces with solidifying materials and subsequent removal of surrounding tissues by corrosive alkali and acids and the inspection of the remaining casts by bare eyes or the dissecting microscope is an old anatomical technique.The introduction of polymerizing resins as casting materials which resulted in durable casts of even the smallest spaces (bile and blood capillaries) and the application of the scanning electron microscope with its high resolution and great depth of focus, enabled the qualitative and the quantitative analysis of the 3D-arrangement of tubular systems by means of their casts.Presently, scanning electron microscopy of microvascular corrosion casts is used to study growing, stable or regressing blood vessel systems under physiological (e.g. during development, wound healing, metamorphosis) and pathological (e.g. tumor angiogenesis) conditions in qualitative and quantitative terms.

Fine structure of the microsymbiont of the actinorhizal root nodules of mountain mahogany (Cercocarpus ledifolius, family Rosaceae)

1989 ◽  
Vol 67 (1) ◽  
pp. 116-120 ◽  
Author(s):  
Susan M. Wood ◽  
William Newcomb ◽  
David Nelson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Root Nodules ◽  
Single Electron ◽  
Transmission Electron ◽  
Cercocarpus Ledifolius ◽  
Scanning Electron

Root nodules of Cercocarpus ledifolius Nutt. (mountain mahogany) were studied by light microscopy, scanning electron microscopy, and transmission electron microscopy to confirm the bacterial nature of the microsymbiont and to determine the morphology of the symbiotic vesicles. The microsymbiont is an actinomycete having two morphologies: septate hyphae (ca. 0.5 μm diam.) and ovoid- or elliptical-shaped nonseptate symbiotic vesicles (2.8 × 3.9 μm). Many of the symbiotic vesicles contain a single, electron-dense ovoid- or spherical-shaped structure, measuring 0.26 μm, whose function is unknown. The actinomycete is surrounded by a capsule that has electron-dense droplets in regions near hyphae. No spores or sporangia were observed in these nodules.

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