scholarly journals ASSEMBLY AND AGGREGATION OF TOBACCO MOSAIC VIRUS IN TOMATO LEAFLETS

1964 ◽  
Vol 21 (2) ◽  
pp. 253-264 ◽  
Author(s):  
Thomas A. Shalla
Keyword(s):  
Electron Microscopy ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Lycopersicum Esculentum ◽  
Rapid Synthesis ◽  
Mesophyll Cells ◽  
Virus Particles ◽  
Particle Aggregates ◽  
Cytological Changes ◽  
Individual Particles

Cells of tomato leaflets (Lycopersicum esculentum Mill.) were studied by phase and electron microscopy at various intervals after inoculation with a common strain of tobacco mosaic virus (TMV). Forty-eight hours after inoculation, prior to the development of assayable virus, individual TMV particles, and also particle aggregates, were observed in the ground cytoplasm of mesophyll cells. The most rapid synthesis of virus occurred between 80 and 300 hours after inoculation. Cytological changes during this time were characterized by an increased number of individual particles in the cytoplasm, growth of some aggregates, distortion and vacuolation of chloroplasts, and formation of filaments in the cytoplasm which were approximately four times the size of TMV. These filaments were interpreted as possible developmental forms of the TMV particle. Vacuoles in chloroplasts commonly contained virus particles. Evidence indicated that TMV was assembled in the ground cytoplasm and, in some cases, subsequently was enveloped by distorted chloroplasts.

scholarly journals RELATION OF TOBACCO MOSAIC VIRUS TO THE HOST CELLS

1967 ◽  
Vol 33 (3) ◽  
pp. 665-678 ◽  
Author(s):  
Katherine Esau ◽  
James Cronshaw
Keyword(s):  
Electron Microscope ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Host Cells ◽  
Vascular Bundles ◽  
Mesophyll Cells ◽  
Virus Particles ◽  
Nicotiana Tabacum L ◽  
Parenchyma Cells ◽  
Particle Aggregates

The relation of tobacco mosaic virus (TMV) to host cells was studied in leaves of Nicotiana tabacum L. systemically infected with the virus. The typical TMV inclusions, striate or crystalline material and ameboid or X-bodies, which are discernible with the light microscope, and/or particles of virus, which are identifiable with the electron microscope, were observed in epidermal cells, mesophyll cells, parenchyma cells of the vascular bundles, differentiating and mature tracheary elements, and immature and mature sieve elements. Virus particles were observed in the nuclei and the chloroplasts of parenchyma cells as well as in the ground cytoplasm, the vacuole, and between the plasma membrane and the cell wall. The nature of the conformations of the particle aggregates in the chloroplasts was compatible with the concept that some virus particles may be assembled in these organelles. The virus particles in the nuclei appeared to be complete particles. Under the electron microscope the X-body constitutes a membraneless assemblage of endoplasmic reticulum, ribosomes, virus particles, and of virus-related material in the form of wide filaments indistinctly resolvable as bundles of tubules. Some parenchyma cells contained aggregates of discrete tubules in parallel arrangement. These groups of tubules were relatively free from components of host protoplasts.

scholarly journals THE STRUCTURE OF CELLS DURING TOBACCO MOSAIC VIRUS REPRODUCTION

1965 ◽  
Vol 25 (3) ◽  
pp. 77-97 ◽  
Author(s):  
L. Kolehmainen ◽  
H. Zech ◽  
D. von Wettstein
Keyword(s):  
Endoplasmic Reticulum ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Electron Scattering ◽  
Osmium Tetroxide ◽  
Crystal Formation ◽  
Mesophyll Cells ◽  
Virus Particles ◽  
Flexible Rods ◽  
Late Stages

The submicroscopic organization of mesophyll cells from tobacco leaves systemically infected with tobacco mosaic virus (TMV) is described. After fixation with glutaraldehyde and osmium tetroxide the arrangement of the TMV particles within the crystalline inclusions is well preserved. Only the ribonucleic acid-containing core of the virus particles is visible in the micrographs. Besides the hexagonal virus crystals, several characteristic types of "inclusion bodies" are definable in the cytoplasm: The so-called fluid crystals seem to correspond to single layers of oriented TMV particles between a network of the endoplasmic reticulum and ribosomes. Unordered groups or well oriented masses of tubes with the diameter of the TMV capsid are found in certain areas of the cytoplasm. A complicated inclusion body is characterized by an extensively branched and folded part of the endoplasmic reticulum, containing in its folds long aggregates of flexible rods. Certain parts of the cytoplasm are filled with large, strongly electron-scattering globules, probably of lipid composition. These various cytoplasmic differentiations and the different forms of presumed virus material are discussed in relation to late stages of TMV reproduction and virus crystal formation.

scholarly journals Chayote Mosaic, a New Disease in Sechium edule Caused by a Tymovirus

Plant Disease ◽  
1997 ◽  
Vol 81 (4) ◽  
pp. 374-378 ◽  
Author(s):  
M. Hord ◽  
W. Villalobos ◽  
A. V. Macaya-Lizano ◽  
C. Rivera
Keyword(s):  
Electron Microscopy ◽  
Mosaic Virus ◽  
Capsid Protein ◽  
Particle Morphology ◽  
Electrophoretic Analysis ◽  
New Disease ◽  
Virus Particles ◽  
Sechium Edule ◽  
Leaf Deformation ◽  
Cytological Changes

A sap-transmissible virus was isolated from chayote (Sechium edule) in Costa Rica. Infected plants showed chlorotic spots and rings, and blotchy mosaics, which often coalesced to give a complete mosaic and leaf deformation. By electron microscopy, spherical virus-like particles of approximately 29 nm in diameter were visible, and cytological changes associated with the chloroplasts were observed. The virus particles sedimented in sucrose density gradients as two components, a top component of empty protein shells and a bottom component of electron-dense particles. Electrophoretic analysis showed a single-stranded RNA of approximately 5.7 kb and capsid protein (CP) subunits of ∼22 kDa. The virus was identified as a member of the tymovirus group on the basis of particle morphology, size, sedimentation in sucrose gradients, cytopathological effects, and capsid protein and genome properties, and it was tentatively named chayote mosaic virus (ChMV).

Electron microscopy of tobacco mosaic virus particles from aphid stylets

Virology ◽  
1963 ◽  
Vol 19 (3) ◽  
pp. 411-412 ◽  
Author(s):  
Chiaki Matsui ◽  
Tsuyoshi Sasaki ◽  
Toshio Kikumoto
Keyword(s):  
Electron Microscopy ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Virus Particles

scholarly journals Coat protein and RNAs of Cole latent virus are not present within chloroplasts of Chenopodium quinoa-infected cells

2003 ◽  
Vol 28 (1) ◽  
pp. 84-88 ◽  
Author(s):  
Priscila Belintani ◽  
José O. Gaspar
Keyword(s):  
Electron Microscopy ◽  
Coat Protein ◽  
Chenopodium Quinoa ◽  
Latent Virus ◽  
Percoll Gradient ◽  
Northern Blots ◽  
Virus Particles ◽  
Ultrastructural Studies ◽  
Particle Aggregates ◽  
Infected Cells

Cole latent virus (CoLV), genus Carlavirus, was studied by electron microscopy and biochemical approaches with respect both to the ultrastructure of the Chenopodium quinoa infected cells and to its association with chloroplasts. The CoLV was observed to be present as scattered particles interspersed with membranous vesicles and ribosomes or as dense masses of virus particles. These virus particles reacted by immunolabelling with a polyclonal antibody to CoLV. Morphologically, chloroplasts, mitochondria and nuclei appeared to be unaltered by virus infection and virus particles were not detected in these organelles. However, virus particle aggregates were frequently associated with the outer membrane of chloroplasts and occasionally with peroxisomes. Chloroplasts were purified by Percoll gradient, and the coat protein and virus-associated RNAs were extracted and analyzed by Western and Northern blots respectively. Coat protein and CoLV-associated RNAs were not detected within this organelle. The results presented in this work indicate that the association CoLV/chloroplasts, observed in the ultrastructural studies, might be a casual event in the host cell, and that the virus does not replicate inside the organelle.

scholarly journals Oligomerization and Activity of the Helicase Domain of the Tobacco Mosaic Virus 126- and 183-Kilodalton Replicase Proteins

2003 ◽  
Vol 77 (6) ◽  
pp. 3549-3556 ◽  
Author(s):  
Sameer P. Goregaoker ◽  
James N. Culver
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Virus Replication ◽  
Protein Interaction ◽  
Gel Filtration ◽  
Helicase Domain ◽  
Protein Protein Interaction ◽  
Replicase Proteins

ABSTRACT A protein-protein interaction within the helicase domain of the Tobacco mosaic virus (TMV) 126- and 183-kDa replicase proteins was previously implicated in virus replication (S. Goregaoker, D. Lewandowski, and J. Culver, Virology 282:320-328, 2001). To further characterize the interaction, polypeptides covering the interacting portions of the TMV helicase domain were expressed and purified. Biochemical characterizations demonstrated that the helicase domain polypeptides hydrolyzed ATP and bound both single-stranded and duplexed RNA in an ATP-controlled fashion. A TMV helicase polypeptide also was capable of unwinding duplexed RNA, confirming the predicted helicase function of the domain. Biochemically active helicase polypeptides were shown by gel filtration to form high-molecular-weight complexes. Electron microscopy studies revealed the presence of ring-like oligomers that displayed six-sided symmetry. Taken together, these data demonstrate that the TMV helicase domain interacts with itself to produce hexamer-like oligomers. Within the context of the full-length 126- and 183-kDa proteins, these findings suggest that the TMV replicase may form a similar oligomer.

The award of medals by the President, Sir Andrew Huxley, O.M., at the Anniversary Meeting, 30 November 1985

1986 ◽  
Vol 405 (1829) ◽  
pp. 181-184
Keyword(s):  
Electron Microscopy ◽  
Image Reconstruction ◽  
Coat Protein ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Deep Insight ◽  
Living Matter ◽  
Fourier Image ◽  
Reconstruction Methods ◽  
Insight Into

The Copley Medal is awarded to Dr A. Klug, F. R. S., in recognition of his outstanding contributions to our understanding of complex biological structures and the methods used for determining them. Together with D. Kaspar, Klug developed a theory that predicted the arrangement of sub-units in the protein shells of spherical viruses. This theory brought order and understanding into a confused field ; nearly all the observed structures of small spherical viruses, many of them elucidated by Klug and his collaborators, are consistent with it. After more than 20 years’ work on tobacco mosaic virus Klug and his colleagues solved the structure of its coat protein in atomic detail. They also elucidated the mechanisms by which the helical virus particle assembles itself from its RNA and its 2130 protein sub-units. Recently his group succeeded in crystallizing chromatin, and solved its structure at a resolution sufficient to see the double-helical DNA coiled around the spool of histone. Many of Klug’s successes were made possible by his introduction of Fourier image reconstruction methods into electron microscopy. Klug’s work is characterized by deep insight into the physics of diffraction and image formation and the intricate geometry of living matter.

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