scholarly journals External scaffold of spherical immature poxvirus particles is made of protein trimers, forming a honeycomb lattice

2005 ◽  
Vol 170 (6) ◽  
pp. 971-981 ◽  
Author(s):  
Patricia Szajner ◽  
Andrea S. Weisberg ◽  
Jacob Lebowitz ◽  
John Heuser ◽  
Bernard Moss
Keyword(s):  
Electron Microscopy ◽  
Amino Acid ◽  
Vaccinia Virus ◽  
Gel Electrophoresis ◽  
Developmental Stages ◽  
Honeycomb Lattice ◽  
Icosahedral Symmetry ◽  
Structural Requirements ◽  
Virus Particles ◽  
Protein Coat

During morphogenesis, poxviruses undergo a remarkable transition from spherical immature forms to brick-shaped infectious particles lacking helical or icosahedral symmetry. In this study, we show that the transitory honeycomb lattice coating the lipoprotein membrane of immature vaccinia virus particles is formed from trimers of a 62-kD protein encoded by the viral D13L gene. Deep-etch electron microscopy demonstrated that anti-D13 antibodies bound to the external protein coat and that lattice fragments were in affinity-purified D13 preparations. Soluble D13 appeared mostly trimeric by gel electrophoresis and ultracentrifugation, which is consistent with structural requirements for a honeycomb. In the presence or absence of other virion proteins, a mutated D13 with one amino acid substitution formed stacks of membrane-unassociated flat sheets that closely resembled the curved honeycombs of immature virions except for the absence of pentagonal facets. A homologous domain that is present in D13 and capsid proteins of certain other lipid-containing viruses support the idea that the developmental stages of poxviruses reflect their evolution from an icosahedral ancestor.

Effect of detergents and chemicals on purified vaccinia virus: analysis by SDS polyacrylamide gel electrophoresis and electron microscopy

1977 ◽  
Vol 23 (3) ◽  
pp. 240-252 ◽  
Author(s):  
J. Boisvert ◽  
T. Yamamoto
Keyword(s):  
Electron Microscopy ◽  
Vaccinia Virus ◽  
Gel Electrophoresis ◽  
Alkali Treatment ◽  
Guanidine Hydrochloride ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Ammonium Bromide ◽  
Molecular Weights ◽  
Viral Particles

Vaccinia virus particles were dissociated into their constituent polypeptides and analysed by sodium dodecyl sulfate (SDS) gel electrophoresis. Thirty-three distinct polypeptide bands were identified and their molecular weights ranged between 11 000 and 150 000 daltons.Specific staining of gels containing polypeptides of dissociated virions revealed the presence of eight glycopeptides. No lipopeptides were detected.Analysis of chemical extracts (urea, guanidine hydrochloride, and alkali treatment) of the virus by SDS gel electrophoresis indicated that a total of 10 to 14 different polypeptides ranging in molecular weights from 11 000 to 70 000 daltons were solubilized.Analysis of detergent extracts and of the remains of extracted viral particles has shown that the detergent Nonidet P-40 (NP-40) solubilized a total of 11 polypeptides of which 6 were glycopeptides. The other detergents sodium deoxycholate (SDC) and cetyl trimethyl ammonium bromide (CTAB) were not as selective, both solubilizing more than 25 of the polypeptides composing the virus. Gel electrophoresis results also indicated that most of the small molecular weight (11 000–70 000 daltons) polypeptides were readily solubilized by NP-40, SDC, and CTAB, while those with molecular weights of 70 000 daltons and higher were not well solubilized.The effects of detergents were also analysed by electron microscopy. Evidence was obtained for subpopulations of viral particles having different susceptibility to detergent extraction.

Poxvirion Spectra

1969 ◽  
Vol 27 ◽  
pp. 224-225
Author(s):  
D. G. Sharp ◽  
Peter Mcguire
Keyword(s):  
Electron Microscopy ◽  
Vaccinia Virus ◽  
Electron Micrographs ◽  
Good Reason ◽  
Virus Particles ◽  
Physical Heterogeneity ◽  
Infected Cells ◽  
The Individual ◽  
Considerable Range ◽  
Highly Uniform

The individual virus particles that comprise the entire population released from a culture of infected cells were once thought to be highly uniform in physical characteristics. Present concepts of virus reproduction have provided no good reason to think otherwise nor have excellent recent electron micrographs of highly purified preparations of vaccinia virus shown obvious physical heterogeneity. Nevertheless a considerable range of heterogeneity does exist, both physical and biological, as shown by a combination of zonal centrifugation, electron microscopy and plaque titration.

scholarly journals First Report of Hibiscus Chlorotic Ringspot Carmovirus in Tuvalu

Plant Disease ◽  
1998 ◽  
Vol 82 (5) ◽  
pp. 591-591
Author(s):  
P. Jones ◽  
J. Devonshire ◽  
A. Dabek ◽  
C. Howells
Keyword(s):  
Electron Microscopy ◽  
Gel Electrophoresis ◽  
Solomon Islands ◽  
Protein Band ◽  
Virus Particles ◽  
Local Spread ◽  
Vitamins A And C ◽  
Single Protein ◽  
The U.S ◽  
Poly Acrylamide

In September 1997, plants of Hibiscus manihot (locally called nambele) were observed on Vaitupu Island, Tuvalu, exhibiting an angular leaf mosaic and chlorosis that was not always clearly discernible. Electron microscopy of negatively stained sap from affected leaves revealed the presence of numerous isometric virus particles 28 nm in diameter. Poly-acrylamide gel electrophoresis of purified virus gave a single protein band of Mr 38,000 similar to that of the carmoviruses. Immunosorbent electron microscopy tests with antisera kindly provided by N. Spence showed the virus to be hibiscus chlorotic ringspot carmovirus (HCRSV) (1). This virus is also reported from El Salvador, the U.S., Australia, Thailand, Malaysia, Fiji, the Solomon Islands, and Vanuatu. It is not known how the virus reached Tuvalu but we suspect it was via infected cuttings, which were imported for the production of food supplements to combat acute deficiencies of vitamins A and C in the population. The virus is most likely to have been disseminated throughout the islands and atolls of Tuvalu through infected cuttings. Local spread within fields could occur through contaminated hands and cutting implements because of the ease with which the virus is mechanically transmitted. Reference: (1) H. E.Waterworth et al. Phytopathology 66:570, 1976.

scholarly journals Dissecting the Seed Maturation and Germination Processes in the Non-Orthodox Quercus ilex Species Based on Protein Signatures as Revealed by 2-DE Coupled to MALDI-TOF/TOF Proteomics Strategy

2020 ◽  
Vol 21 (14) ◽  
pp. 4870 ◽  
Author(s):  
Besma Sghaier-Hammami ◽  
Sofiene B.M. Hammami ◽  
Narjes Baazaoui ◽  
Consuelo Gómez-Díaz ◽  
Jesús V. Jorrín-Novo
Keyword(s):  
Amino Acid ◽  
Gel Electrophoresis ◽  
Quercus Ilex ◽  
Developmental Stages ◽  
Tricarboxylic Acid Cycle ◽  
Seed Maturation ◽  
Embryo Axis ◽  
Two Dimensional Gel Electrophoresis ◽  
Cell Defense ◽  
Maldi Tof

Unlike orthodox species, seed recalcitrance is poorly understood, especially at the molecular level. In this regard, seed maturation and germination were studied in the non-orthodox Quercus ilex by using a proteomics strategy based on two-dimensional gel electrophoresis coupled to matrix-assisted laser desorption ionization/time of flight (2-DE-MALDI-TOF).Cotyledons and embryo/radicle were sampled at different developmental stages, including early (M1–M3), middle (M4–M7), and late (M8–M9) seed maturation, and early (G1–G3) and late (G4–G5) germination. Samples corresponding to non-germinating, inviable, seeds were also included. Protein extracts were subjected to 2-dimensional gel electrophoresis (2-DE) and changes in the protein profiles were analyzed. Identified variable proteins were grouped according to their function, being the energy, carbohydrate, lipid, and amino acid metabolisms, together with protein fate, redox homeostasis, and response to stress are the most represented groups. Beyond the visual aspect, morphometry, weight, and water content, each stage had a specific protein signature. Clear tendencies for the different protein groups throughout the maturation and germination stages were observed for, respectively, cotyledon and the embryo axis. Proteins related to metabolism, translation, legumins, proteases, proteasome, and those stress related were less abundant in non-germinating seeds, it related to the loss of viability. Cotyledons were enriched with reserve proteins and protein-degrading enzymes, while the embryo axis was enriched with proteins of cell defense and rescue, including heat-shock proteins (HSPs) and antioxidants. The peaks of enzyme proteins occurred at the middle stages (M6–M7) in cotyledons and at late ones (M8–M9) in the embryo axis. Unlike orthodox seeds, proteins associated with glycolysis, tricarboxylic acid cycle, carbohydrate, amino acid and lipid metabolism are present at high levels in the mature seed and were maintained throughout the germination stages. The lack of desiccation tolerance in Q. ilex seeds may be associated with the repression of some genes, late embryogenesis abundant proteins being one of the candidates.

Recent Applications of High Resolution Electron Microscopy to Crystalline Arrays of Virus Particles

1978 ◽  
Vol 36 (3) ◽  
pp. 470-482 ◽  
Author(s):  
R.W. Horne
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Analytical Techniques ◽  
Staining Technique ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Full Potential ◽  
Virus Particles ◽  
Resolution Electron ◽  
Wide Range

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.

Uranyl Acetate and Rotary Shadowing to Increase the Contrast of Small Aggregated Virus Particles

1969 ◽  
Vol 27 ◽  
pp. 424-425
Author(s):  
Lee F. Ellis ◽  
Richard M. Van Frank ◽  
Walter J. Kleinschmidt
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Uranyl Acetate ◽  
Interferon Inducer ◽  
Virus Particles ◽  
Staining Methods ◽  
Rotary Shadowing

The extract from Penicillum stoliniferum, known as statolon, has been purified by density gradient centrifugation. These centrifuge fractions contained virus particles that are an interferon inducer in mice or in tissue culture. Highly purified preparations of these particles are difficult to enumerate by electron microscopy because of aggregation. Therefore a study of staining methods was undertaken.

Aberrant Type C Virus Production in a Cell Line Derived from Balb/3T3

1972 ◽  
Vol 30 ◽  
pp. 286-287
Author(s):  
N. Savage ◽  
A. Hackett
Keyword(s):  
Electron Microscopy ◽  
Cell Line ◽  
Leukemia Virus ◽  
Morphological Characteristics ◽  
Virus Production ◽  
Oncogenic Viruses ◽  
Endogenous Virus ◽  
Virus Particles ◽  
Moloney Leukemia Virus ◽  
A Cell

A cell line, UC1-B, which was derived from Balb/3T3 cells, maintains the same morphological characteristics of the non-transformed parental culture, and shows no evidence of spontaneous virus production. Survey by electron microscopy shows that the cell line consists of spindle-shaped cells with no unusual features and no endogenous virus particles.UC1-B cells respond to Moloney leukemia virus (MLV) infection by a change in morphology and growth pattern which is typical of cells transformed by sarcoma virus. Electron microscopy shows that the cells are now variable in shape (rounded, rhomboid, and spindle), and each cell type has some microvilli. Virtually all (90%) of the cells show virus particles developing at the cell surface and within the cytoplasm. Maturing viruses, typical of the oncogenic viruses, are found along with atypical tubular forms in the same cell.

Head Size and DNA Content in Bacteriophage T4

1972 ◽  
Vol 30 ◽  
pp. 200-201
Author(s):  
Fred Eiserling ◽  
A. H. Doermann ◽  
Linde Boehner
Keyword(s):  
Electron Microscopy ◽  
Dna Content ◽  
Bacteriophage T4 ◽  
Head Size ◽  
Virus Particles ◽  
Altered Protein ◽  
A Cell ◽  
Bacterial Viruses ◽  
A Site ◽  
Protein Shell

The control of form or shape inheritance can be approached by studying the morphogenesis of bacterial viruses. Shape variants of bacteriophage T4 with altered protein shell (capsid) size and nucleic acid (DNA) content have been found by electron microscopy, and a mutant (E920g in gene 66) controlling head size has been described. This mutant produces short-headed particles which contain 2/3 the normal DNA content and which are non-viable when only one particle infects a cell (Fig. 1).We report here the isolation of a new mutant (191c) which also appears to be in gene 66 but at a site distinct from E920g. The most striking phenotype of the mutant is the production of about 10% of the phage yield as “giant” virus particles, from 3 to 8 times longer than normal phage (Fig. 2).

Electron Microscope Study of RNA's of Paramyxoviruses

1972 ◽  
Vol 30 ◽  
pp. 196-197
Author(s):  
Ruchama Baum ◽  
J.T. Seto
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Microscope Study ◽  
Sendai Virus ◽  
Sodium Dodecyl ◽  
Rna Molecules ◽  
Virus Particles ◽  
Molecular Weights ◽  
Length Measurements

The ribonucleic acid (RNA) of paramyxoviruses has been characterized by biochemical and physiochemical methods. However, paramyxovirus RNA molecules have not been studied by electron microscopy. The molecular weights of these single-stranded viral RNA molecules are not known as yet. Since electron microscopy has been found to be useful for the characterization of single-stranded RNA, this investigation was initiated to examine the morphology and length measurements of paramyxovirus RNA's.Sendai virus Z strain and Newcastle disease virus (NDV), Milano strain, were used. For these studies it was necessary to develop a method of extracting RNA molecules from purified virus particles. Highly purified Sendai virus was treated with pronase (300 μg/ml) at 37°C for 30 minutes and the RNA extracted by the sodium dodecyl sulfate (SDS)-phenol procedure.

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