Root and Root Endophytes from the Eyes of an Electron Microscopist

Electron microscopy in diagnostic virology

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100110702 ◽

1984 ◽

Vol 42 ◽

pp. 70-73

Author(s):

S. E. Miller

Keyword(s):

Electron Microscopy ◽

Tissue Culture ◽

Molecular Identification ◽

Point Of View ◽

Negative Stain ◽

Viral Diagnosis ◽

Electron Microscopist ◽

Diagnostic Virology

The techniques for detecting viruses are many and varied including FAT, ELISA, SPIRA, RPHA, SRH, TIA, ID, IEOP, GC (1); CF, CIE (2); Tzanck (3); EM, IEM (4); and molecular identification (5). This paper will deal with viral diagnosis by electron microscopy and will be organized from the point of view of the electron microscopist who is asked to look for an unknown agent--a consideration of the specimen and possible agents rather than from a virologist's view of comparing all the different viruses. The first step is to ascertain the specimen source and select the method of preparation, e. g. negative stain or embedment, and whether the sample should be precleared by centrifugation, concentrated, or inoculated into tissue culture. Also, knowing the type of specimen and patient symptoms will lend suggestions of possible agents and eliminate some viruses, e. g. Rotavirus will not be seen in brain, nor Rabies in stool, but preconceived notions should not prejudice the observer into missing an unlikely pathogen.

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Absolute inner-shell cross section determination for EELS analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010473x ◽

1988 ◽

Vol 46 ◽

pp. 534-535

Author(s):

P.A. Crozier

Keyword(s):

Cross Section ◽

Cross Sections ◽

Absolute Cross Section ◽

Specimen Thickness ◽

Mass Thickness ◽

Scattering Cross ◽

Before And After ◽

Estimated Error ◽

Scattering Cross Sections ◽

Electron Microscopist

Absolute inelastic scattering cross sections or mean free paths are often used in EELS analysis for determining elemental concentrations and specimen thickness. In most instances, theoretical values must be used because there have been few attempts to determine experimental scattering cross sections from solids under the conditions of interest to electron microscopist. In addition to providing data for spectral quantitation, absolute cross section measurements yields useful information on many of the approximations which are frequently involved in EELS analysis procedures. In this paper, experimental cross sections are presented for some inner-shell edges of Al, Cu, Ag and Au.Uniform thin films of the previously mentioned materials were prepared by vacuum evaporation onto microscope cover slips. The cover slips were weighed before and after evaporation to determine the mass thickness of the films. The estimated error in this method of determining mass thickness was ±7 x 107g/cm2. The films were floated off in water and mounted on Cu grids.

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Valence electron spectroscopy of inhomogeneous media

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130389 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1150-1151

Author(s):

A. Howie ◽

D.W. McComb

Keyword(s):

Specific Gravity ◽

Loss Function ◽

Electron Spectroscopy ◽

Valence Electron ◽

Peak Height ◽

Loss Functions ◽

Loss Peak ◽

High Energies ◽

Valence Electron Density ◽

Electron Microscopist

The bulk loss function Im(-l/ε (ω)), a well established tool for the interpretation of valence loss spectra, is being progressively adapted to the wide variety of inhomogeneous samples of interest to the electron microscopist. Proportionality between n, the local valence electron density, and ε-1 (Sellmeyer's equation) has sometimes been assumed but may not be valid even in homogeneous samples. Figs. 1 and 2 show the experimentally measured bulk loss functions for three pure silicates of different specific gravity ρ - quartz (ρ = 2.66), coesite (ρ = 2.93) and a zeolite (ρ = 1.79). Clearly, despite the substantial differences in density, the shift of the prominent loss peak is very small and far less than that predicted by scaling e for quartz with Sellmeyer's equation or even the somewhat smaller shift given by the Clausius-Mossotti (CM) relation which assumes proportionality between n (or ρ in this case) and (ε - 1)/(ε + 2). Both theories overestimate the rise in the peak height for coesite and underestimate the increase at high energies.

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A program for simulation of changes in diffraction patterns with crystal rotations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100181476 ◽

1990 ◽

Vol 48 (1) ◽

pp. 544-545

Author(s):

F.C. Mijlhoff ◽

H.W. Zandbergenl

Keyword(s):

Electron Microscope ◽

Reciprocal Lattice ◽

Extensive Training ◽

Diffraction Mode ◽

Diffraction Patterns ◽

Electron Microscopist

Orientation of crystals for HREM is done in diffraction mode. To do this efficiently thorough knowledge of the electron microscope and the reciprocal lattice of the investigated material is essential. With respect to the electron microscope extensive training is required to obtain the ability to tilt a crystal in the desired orientation. Familiarity with the reciprocal lattice of the investigated materials has to be obtained by tilt experiments on a relatively large number of crystals in the electron microscope. Even for experienced electron microscopists this can be very time consuming.In order to be able to practice tilt experiments without using the electron microscope, a program to simulate the electron microscope in diffraction mode was developed. The inexperienced electron microscopist may use the program to practice tilting of crystals. The experienced microscopist can use the program to familiarize with the reciprocal lattice of materials, which have not been studied by him before.

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Effect of Ionizing Radiation on the Bacterial and Fungal Endophytes of the Halophytic Plant Kalidium schrenkianum

Microorganisms ◽

10.3390/microorganisms9051050 ◽

2021 ◽

Vol 9 (5) ◽

pp. 1050

Author(s):

Jing Zhu ◽

Xiang Sun ◽

Zhi-Dong Zhang ◽

Qi-Yong Tang ◽

Mei-Ying Gu ◽

...

Keyword(s):

Genetic Diversity ◽

Ionizing Radiation ◽

Endophytic Bacteria ◽

Fungal Endophytes ◽

Root Endophytes ◽

Fungal Community Structure ◽

Geochemical Factors ◽

Bacteria And Fungi ◽

High Level ◽

And Control

Endophytic bacteria and fungi colonize plants that grow in various types of terrestrial and aquatic ecosystems. Our study investigates the communities of endophytic bacteria and fungi of halophyte Kalidium schrenkianum growing in stressed habitats with ionizing radiation. The geochemical factors and radiation (at low, medium, high level and control) both affected the structure of endophytic communities. The bacterial class Actinobacteria and the fungal class Dothideomycetes predominated the endophytic communities of K. schrenkianum. Aerial tissues of K. schrenkianum had higher fungal diversity, while roots had higher bacterial diversity. Radiation had no significant effect on the abundance of bacterial classes. Soil pH, total nitrogen, and organic matter showed significant effects on the diversity of root endophytes. Radiation affected bacterial and fungal community structure in roots but not in aerial tissues, and had a strong effect on fungal co-occurrence networks. Overall, the genetic diversity of both endophytic bacteria and fungi was higher in radioactive environments, however negative correlations were found between endophytic bacteria and fungi in the plant. The genetic diversity of both endophytic bacteria and fungi was higher in radioactive environments. Our findings suggest that radiation affects root endophytes, and that the endophytes associated with aerial tissues and roots of K. schrenkianum follow different mechanisms for community assembly and different paradigms in stress response.

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