scholarly journals Epoxy Resins in Electron Microscopy

1960 ◽  
Vol 7 (1) ◽  
pp. 27-30 ◽  
Author(s):  
Henry Finck
Keyword(s):  
Electron Microscopy ◽  
United States ◽  
Electron Beam ◽  
Epoxy Resins ◽  
The United States ◽  
High Viscosity

A method of embedding biological specimens in araldite 502 (Ciba) has been developed for materials available in the United States. Araldite-embedded tissues are suitable for electron microscopy, but the cutting qualities of the resin necessitates more than routine attention during microtomy. The rather high viscosity of araldite 502 also seems to be an unnecessary handicap. The less viscous epoxy epon 812 (Shell) produces specimens with improved cutting qualities, and has several features—low shrinkage and absence of specimen damage during cure, minimal compression of sections, relative absence of electron beam-induced section damage, etc.—which recommends it as a routine embedding material. The hardness of the cured resin can be easily adjusted by several methods to suit the materials embedded in it. Several problems and advantages of working with sections of epoxy resins are also discussed.

Epoxy Resin Embedment

1968 ◽  
Vol 26 ◽  
pp. 100-101
Author(s):  
J. G. Adams ◽  
M. M. Campbell ◽  
H. Thomas ◽  
J. J. Ghldonl
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Epoxy Resin ◽  
Light Microscope ◽  
Epoxy Resins ◽  
Image Contrast ◽  
Tissue Preservation ◽  
Resin System ◽  
Excellent Quality

Since the introduction of epoxy resins as embedding material for electron microscopy, the list of new formulations and variations of widely accepted mixtures has grown rapidly. Described here is a resin system utilizing Maraglas 655, Dow D.E.R. 732, DDSA, and BDMA, which is a variation of the mixtures of Lockwood and Erlandson. In the development of the mixture, the Maraglas and the Dow resins were tested in 3 different volumetric proportions, 6:4, 7:3, and 8:2. Cutting qualities and characteristics of stability in the electron beam and image contrast were evaluated for these epoxy mixtures with anhydride (DDSA) to epoxy ratios of 0.4, 0.55, and 0.7. Each mixture was polymerized overnight at 60°C with 2% and 3% BDMA.Although the differences among the test resins were slight in terms of cutting ease, general tissue preservation, and stability in the beam, the 7:3 Maraglas to D.E.R. 732 ratio at an anhydride to epoxy ratio of 0.55 polymerized with 3% BDMA proved to be most consistent. The resulting plastic is relatively hard and somewhat brittle which necessitates trimming and facing the block slowly and cautiously to avoid chipping. Sections up to about 2 microns in thickness can be cut and stained with any of several light microscope stains and excellent quality light photomicrographs can be taken of such sections (Fig. 1).

scholarly journals Future Measurements of the Nucleon Elastic Electromagnetic Form Factors at Jefferson Lab

2018 ◽  
Vol 172 ◽  
pp. 02004 ◽  
Author(s):  
Gerard Gilfoyle
Keyword(s):  
United States ◽  
Electron Beam ◽  
Form Factors ◽  
The United States ◽  
Precision Measurements ◽  
Electromagnetic Form Factors ◽  
Jefferson Lab ◽  
Atomic Nuclei ◽  
Perturbative Regime ◽  
Nucleon Form Factors

The elastic, electromagnetic form factors are fundamental observables that describe the internal structure of protons, neutrons, and atomic nuclei. Jefferson Lab in the United States has completed the 12 GeV Upgrade that will open new opportunities to study the form factors. A campaign to measure all four nucleon form factors (electric and magnetic ones for both proton and neutron) has been approved consisting of seven experiments in Halls A, B, and C. The increased energy of the electron beam will extend the range of precision measurements to higher Q2 for all four form factors together. This combination of measurements will allow for the decomposition of the results into their quark components and guide the development of a QCD-based understanding of nuclei in the non-perturbative regime. I will present more details on the 12 GeV Upgrade, the methods used to measure the form factors, and what we may learn.

scholarly journals Alternanthera mosaic virus Found in Scutellaria, Crossandra, and Portulaca spp. in Florida

Plant Disease ◽  
2006 ◽  
Vol 90 (6) ◽  
pp. 833-833 ◽  
Author(s):  
C. A. Baker ◽  
L. Breman ◽  
L. Jones
Keyword(s):  
Electron Microscopy ◽  
United States ◽  
Mosaic Virus ◽  
Plant Species ◽  
The United States ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rt Pcr ◽  
Indicator Plants ◽  
Partial Identity ◽  
Pcr Products

In the fall of 1998, the Division of Plant Industry (DPI) received vegetative propagations of Scutellaria longifolia (skullcap) with symptoms of foliar mosaic, chlorotic/necrotic ringspots, and wavy line patterns from a nursery in Manatee County. Flexuous particles approximately 500 nm long were found with electron microscopy. The plants tested positive for Papaya mosaic virus (PaMV) in an enzyme-linked immunosorbent assay (ELISA) test with antiserum to PaMV (Agdia, Elkhart, IN). However, in immunodiffusion tests (antiserum from D. Purcifull, University of Florida), this virus gave a reaction of partial identity indicating it was related but not identical to PaMV (1). The original infected plants were kept in a greenhouse. In January 2005, a specimen of Crossandra infundibuliformis (firecracker plant) with mosaic symptoms was submitted to the DPI from a nursery in Alachua County. Inclusions found with light microscopy and particles found with electron microscopy indicated that this plant was infected with a potexvirus. This was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) with primers designed to detect members of the virus family Potexviridae (3). These plants reacted positive to PaMV antiserum in ELISA and gave a reaction of partial identity to PaMV in immunodiffusion. A specimen of Portulaca grandiflora (moss rose) with distorted leaves found at a local retail store was also tested and gave the same results. Leaves from each of the three plant species were rubbed onto a set of indicator plants using Carborundum and potassium phosphate buffer. Total RNA was extracted from symptomatic indicator plants of Nicotiana benthamiana. RT-PCR (3) was performed, and PCR products were sequenced directly. Sequences of approximately 700 bp were obtained for all three plant species and showed 98% identity with each other. BLAST search results showed that these sequences were 93% identical to an Alternanthera mosaic virus (AltMV) sequence at the nucleotide level but only 76% identical to PaMV. The amino acid sequences were 98 and 82% identical to AltMV and PaMV, respectively. The PCR products of the virus from Scutellaria sp. were cloned, resequenced, and the sequence was entered into the GenBank (Accession No. DQ393785). The bioassay results matched those found for AltMV in Australia (2) and the northeastern United States (4), except that the Florida viruses infected Datura stramonium and Digitalis purpurea (foxglove). The virus associated with the symptoms of these three plants appears to be AltMV and not PaMV. AltMV has been found in ornamental plants in Australia, Italy, and the United States (Pennsylvania, Maryland, and now Florida). Since this virus is known to infect several plants asymptomatically and can be easily confused with PaMV serologically, it is likely that the distribution of this virus is much wider than is known at this time. References: (1) L. L. Breman. Plant Pathology Circular No. 396. Fla. Dept. Agric. Consum. Serv. DPI, 1999. (2) A. D. W. Geering and J. E. Thomas. Arch Virol 144:577, 1999. (3) A. Gibbs et al. J Virol Methods 74:67, 1998. (4) J. Hammond et al. Arch Virol. 151:477, 2006.

Induction of Prophage in Lactic Streptococci Isolated from Commercial Dairy Starter Cultures1

1975 ◽  
Vol 38 (10) ◽  
pp. 594-597 ◽  
Author(s):  
CHANHO PARK ◽  
L. L. McKAY
Keyword(s):  
Electron Microscopy ◽  
United States ◽  
Mitomycin C ◽  
Ultraviolet Irradiation ◽  
The United States ◽  
Starter Cultures ◽  
Indicator Organisms ◽  
Streptococcus Cremoris ◽  
Dairy Starter Cultures ◽  
Dairy Starter

Twelve commercial dairy starter cultures were examined for presence of lysogens by treating isolated strains with ultraviolet irradiation or mitomycin C. Induction of lysis in isolates from nine of the 12 commercial cultures suggested the presence of lysogenic strains. No indicator organisms were detected, but presence of phage was confirmed by electron microscopy in two of the Streptococcus cremoris isolates from the commercial cultures. The results confirm that some commercial dairy cultures produced in the United States contain phage-harboring strains.

Ultrastructure Of Conidium And Disjunctor Development In The Plant Pathogenic Fungus Monilinia Vaccinii-Corymbosi

1999 ◽  
Vol 5 (S2) ◽  
pp. 1278-1279
Author(s):  
C. W. Mims ◽  
E. A. Richardson
Keyword(s):  
Electron Microscopy ◽  
United States ◽  
Scanning Electron Microscopy ◽  
Pathogenic Fungus ◽  
The United States ◽  
Exact Nature ◽  
Taxonomic Character ◽  
Plant Pathogenic Fungus ◽  
Disease Initiation ◽  
Scanning Electron

Monilinia vaccinii-corymbosi is the cause of mummy berry disease of commercial blueberries (Vaccinium spp.) grown in the United States and Canada (1). Ovaries of blueberry flowers are infected by the conidia (asexual spores) of this pathogen. However, despite their importance in disease initiation, little is known of the ultrastructural features of these conidia. The only ultrastructural data on these spores has come from the work of Batra (2) who used scanning electron microscopy to describe the morphology of the so-called “disjunctors” which connect adjacent conidia of M. vaccinii-corymbosi. The presence or absence of disjunctors is an important taxonomic character in the genus Monilinia (1) but little is known of their development and exact nature. The objective of this study was, therefore, to elucidate details of conidium and disjunctor development in M. vaccinii-corymbosi.

The Use of Epoxy Resins in Field Projects for Stone Stabilization

1992 ◽  
Vol 267 ◽  
Author(s):  
Charles M. Selwitz
Keyword(s):  
United States ◽  
Organic Solvents ◽  
Epoxy Resins ◽  
The United States ◽  
Direct Application ◽  
Color Formation ◽  
Moderate Size

ABSTRACTThe direct application of epoxy resins to deteriorating stone often encounters problems of penetration and color formation. Conservation scientists have worked around these problems by using organic solvents as carriers and have successfully consolidated stone with epoxy resins in a large number of projects. Work in Poland, Czechoslovakia, Italy and the United States is described. In Europe the methodology has evolved to treat objects of moderate size and isolated parts of buildings while in the United States procedures have been developed for stabilizing large portions of major buildings.

scholarly journals Dicentra, Epimedium, and Heuchera: New Perennial Ornamental Hosts of Tobacco rattle virus in the United States

Plant Disease ◽  
2000 ◽  
Vol 84 (12) ◽  
pp. 1344-1344 ◽  
Author(s):  
B. E. L. Lockhart
Keyword(s):  
Electron Microscopy ◽  
United States ◽  
Tobacco Rattle Virus ◽  
Leaf Tissue ◽  
Particle Morphology ◽  
The United States ◽  
Enzyme Linked Immunosorbent Assay ◽  
Infected Leaf ◽  
Natural Occurrence ◽  
First Report

Yellow ringspotting and concentric line patterns in plants of Dicentra (bleeding heart), Epimedium (barrenwort), and Heuchera (coral bells) from commercial nurseries and home gardens in Minnesota, Michigan, and Massachusetts were associated with infection by Tobacco rattle virus (TRV), which was identified by particle morphology, enzyme-linked immunosorbent assay and immunosorbent electron microscopy. No other viruslike particles were observed by electron microscopy in partially purified preparations of TRV-infected leaf tissue, and TRV was not detected in asymptomatic plants. This is the first report of TRV occurrence in Dicentra in the United States and the first report of TRV occurrence in Epimedium and Heuchera. In previous reports (1,2) we have called attention to the increasing incidence of TRV in vegetatively propagated perennial ornamental plant species in the United States and to the potential for virus spread to crops such as potato, in which TRV has not been reported in the midwestern United States. It is possible that increased international trade in vegetatively propagated ornamental plants may be resulting in the introduction of TRV and other exotic viruses into the United States and elsewhere. It is also possible that the natural occurrence of TRV in North America may be actually more widespread than has been reported. References: (1) B. E. Lockhart et al. Plant Dis. 79:1249, 1995. (2) B. E. Lockhart and J. A. Westendorp. Plant Dis. 82:712, 1998.

Purification and Ultrastructural Analysis of Terminal Sequences from the Cross-Linked, Linear Plasmids of Borrelia Burgdorferi

1990 ◽  
Vol 48 (3) ◽  
pp. 128-129
Author(s):  
Lori L. Lubke ◽  
Claude F. Garon
Keyword(s):  
Electron Microscopy ◽  
United States ◽  
Borrelia Burgdorferi ◽  
Methyl Mercury ◽  
The United States ◽  
Linear Plasmids ◽  
Circular Dna ◽  
Restriction Fragments ◽  
Ion Exchange Column ◽  
Alkaline Denaturation

Lyme borreliosis is now the most common arthropod-borne disease in the United States. Borrelia burgdorferi, the causative agent, has been isolated from humans, mammals, birds and arthropods and is cultivable in the laboratory. Careful structural analysis of the DNA content of several isolates has revealed, in addition to a 900 kb linear genome, a unique collection of crosslinked linear and covalently closed, circular DNA molecules ranging from 2-50 kb in length. While all of the linear species were shown to rapidly reanneal to linear duplexes after alkaline denaturation, single-stranded circular molecules measuring twice the length of the linears could be produced by treatment with methyl mercury, glyoxal and urea prior to mounting for electron microscopy. This rapid reannealing mediated by the terminal sequences of the molecule was used in a unique ion exchange column chromatography system to purify terminal, restriction fragments from any which originate internally. Purified terminal fragments could then be compared and characterized further by conventional methods.

Punctastriata altera sp. nov. (Bacillariophyta, Fragilariophyceae), a diatom from the United States of America

Phytotaxa ◽  
2021 ◽  
Vol 516 (3) ◽  
Author(s):  
EDUARDO A. MORALES
Keyword(s):  
Electron Microscopy ◽  
United States ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
United States Of America ◽  
The United States ◽  
Scanning Electron

The genus Punctastriata D.M.Williams & Round (1988: 278) contains 10 species that are difficult to identify under light microscopy (LM) (Wetzel & Ector 2021, Morales et al. 2021). The difficulty lies in the differentiation of the overall valve outline and striation pattern of these species from members of Staurosirella D.M.Williams & Round (1988: 274). Under scanning electron microscopy (SEM), the striae of species of Punctastriata are typically multiseriate, the consequence of a profuse formation of viminules. In Staurosirella, the striae are composed of long and slender vimines delimiting apically oriented lineolae (Morales et al. 2021), while the production of viminules is incomplete and rare (Morales 2005).

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