Ultrastructural Changes in Leaf Tissues of Populusdeltoides spp. angulata Ait. Infected with Poplar Mosaic Virus

1972 ◽  
Vol 2 (3) ◽  
pp. 308-312 ◽  
Author(s):  
S. Navratil ◽  
M. G. Boyer
Keyword(s):  
Endoplasmic Reticulum ◽  
Mosaic Virus ◽  
Ultrastructural Changes ◽  
Cell Organelles ◽  
Sieve Elements ◽  
Virus Particles ◽  
Chloroplast Membrane ◽  
Leaf Tissues ◽  
Infected Cells

Ultrastructural observations on the foliar cells of Populusdeltoides spp. angulata Ait. infected by poplar mosaic virus revealed a high content of virus particles in the cytoplasm of most but not all young cells from chlorotic areas. Mature cells from necrotic areas contained far fewer virions while in symptomless green portions no virions were observed. Virus particles were not found in mature sieve elements or in mature nonliving xylem cells.Changes in the cytoplasm and in chloroplasts were followed. Healthy, mature chloroplasts contained well developed thylakoid systems. In infected cells, a disintegrative process at necrotization resulted in the dissolution of the thylakoid system into individual electron dense sacs which were released when the chloroplast membrane dissolved. Cytoplasmic changes were characterized by increased vacuolation. Cisternae of the endoplasmic reticulum and vesiculate bodies were also more numerous. Necrotization was accompanied by dissolution of the cell organelles.

The appearance of eight strains of alfalfa mosaic virus in alfalfa leaves and their effect on the ultrastructure of infected cells

1974 ◽  
Vol 52 (5) ◽  
pp. 979-985 ◽  
Author(s):  
Roy D. Wilcoxson ◽  
F. I. Frosheiser ◽  
Lois B. Johnson
Keyword(s):  
Mosaic Virus ◽  
Alfalfa Mosaic Virus ◽  
Leaf Tissue ◽  
Cell Organelles ◽  
Virus Particles ◽  
Vascular Parenchyma ◽  
Infected Cells ◽  
Medicago Sativa L ◽  
Ultrastructural Damage ◽  
Apparently Healthy

Eight strains of alfalfa mosaic virus (AMV) were studied by electron microscopy in alfalfa (Medicago sativa L.) leaf tissue and after purification. The virus occurred in the cytoplasm and occasionally in the vacuoles of mesophyll and vascular parenchyma cells; it was not associated with cell organelles. One strain of AMV (U5) did not incite symptoms in the alfalfa leaves and caused no ultrastructural damage to the infected cells. Two strains (U10 and U21) caused no symptoms in alfalfa, but the tonoplast of infected cells was not closely attached to the cytoplasm and floated in the vacuole; cell organelles were not damaged. The other five strains of AMV (F1, NY1, R6, B1, and W1) regularly or occasionally produced symptoms in alfalfa leaves. In leaves that were symptomless, as well as in the apparently healthy parts of leaves with symptoms of AMV infection, there was no apparent ultrastructural damage to the infected cells. Within the part of a leaf where there were symptoms, the tonoplast was detached from the cytoplasma and was folded within the vacuole in various patterns, along with bits of cytoplasm and virus particles. Cell organelles were often found in various stages of disintegration. Three different aggregations of the virus were recognized. The eight AMV strains were grouped into three general classes on the basis of the range in virus particle sizes. Mycoplasm was not associated with any of the AMV strains.

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 Particle Assembly and Ultrastructural Features Associated with Replication of the Lytic Archaeal Virus Sulfolobus Turreted Icosahedral Virus

2009 ◽  
Vol 83 (12) ◽  
pp. 5964-5970 ◽  
Author(s):  
Susan K. Brumfield ◽  
Alice C. Ortmann ◽  
Vincent Ruigrok ◽  
Peter Suci ◽  
Trevor Douglas ◽  
...  
Keyword(s):  
Time Course ◽  
Plaque Assay ◽  
Ultrastructural Changes ◽  
Progeny Virus ◽  
Particle Assembly ◽  
Virus Particles ◽  
Transmission Electron ◽  
Archaeal Viruses ◽  
Infected Cells ◽  
Sulfolobus Turreted Icosahedral Virus

ABSTRACT Little is known about the replication cycle of archaeal viruses. We have investigated the ultrastructural changes of Sulfolobus solfataricus P2 associated with infection by Sulfolobus turreted icosahedral virus (STIV). A time course of a near synchronous STIV infection was analyzed using both scanning and transmission electron microscopy. Assembly of STIV particles, including particles lacking DNA, was observed within cells, and fully assembled STIV particles were visible by 30 h postinfection (hpi). STIV was determined to be a lytic virus, causing cell disruption beginning at 30 hpi. Prior to cell lysis, virus infection resulted in the formation of pyramid-like projections from the cell surface. These projections, which have not been documented in any other host-virus system, appeared to be caused by the protrusion of the cell membrane beyond the bordering S-layer. These structures are thought to be sites at which progeny virus particles are released from infected cells. Based on these observations of lysis, a plaque assay was developed for STIV. From these studies we propose an overall assembly model for STIV.

scholarly journals Nucleocapsid Protein from Fig Mosaic Virus Forms Cytoplasmic Agglomerates That Are Hauled by Endoplasmic Reticulum Streaming

2014 ◽  
Vol 89 (1) ◽  
pp. 480-491 ◽  
Author(s):  
Kazuya Ishikawa ◽  
Chihiro Miura ◽  
Kensaku Maejima ◽  
Ken Komatsu ◽  
Masayoshi Hashimoto ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Mosaic Virus ◽  
Nucleocapsid Protein ◽  
Plant Cells ◽  
Network Configuration ◽  
Negative Strand ◽  
Intracellular Movement ◽  
Close Proximity ◽  
Infected Cells ◽  
Fig Mosaic Virus

ABSTRACTAlthough many studies have demonstrated intracellular movement of viral proteins or viral replication complexes, little is known about the mechanisms of their motility. In this study, we analyzed the localization and motility of the nucleocapsid protein (NP) ofFig mosaic virus(FMV), a negative-strand RNA virus belonging to the recently established genusEmaravirus. Electron microscopy of FMV-infected cells using immunogold labeling showed that NPs formed cytoplasmic agglomerates that were predominantly enveloped by the endoplasmic reticulum (ER) membrane, while nonenveloped NP agglomerates also localized along the ER. Likewise, transiently expressed NPs formed agglomerates, designated NP bodies (NBs), in close proximity to the ER, as was the case in FMV-infected cells. Subcellular fractionation and electron microscopic analyses of NP-expressing cells revealed that NBs localized in the cytoplasm. Furthermore, we found that NBs moved rapidly with the streaming of the ER in an actomyosin-dependent manner. Brefeldin A treatment at a high concentration to disturb the ER network configuration induced aberrant accumulation of NBs in the perinuclear region, indicating that the ER network configuration is related to NB localization. Dominant negative inhibition of the class XI myosins, XI-1, XI-2, and XI-K, affected both ER streaming and NB movement in a similar pattern. Taken together, these results showed that NBs localize in the cytoplasm but in close proximity to the ER membrane to form enveloped particles and that this causes passive movements of cytoplasmic NBs by ER streaming.IMPORTANCEIntracellular trafficking is a primary and essential step for the cell-to-cell movement of viruses. To date, many studies have demonstrated the rapid intracellular movement of viral factors but have failed to provide evidence for the mechanism or biological significance of this motility. Here, we observed that agglomerates of nucleocapsid protein (NP) moved rapidly throughout the cell, and we performed live imaging and ultrastructural analysis to identify the mechanism of motility. We provide evidence that cytoplasmic protein agglomerates were passively dragged by actomyosin-mediated streaming of the endoplasmic reticulum (ER) in plant cells. In virus-infected cells, NP agglomerates were surrounded by the ER membranes, indicating that NP agglomerates form the basis of enveloped virus particles in close proximity to the ER. Our work provides a sophisticated model of macromolecular trafficking in plant cells and improves our understanding of the formation of enveloped particles of negative-strand RNA viruses.

scholarly journals Detection of Poinsettia mosaic virus Infecting Poinsettias (Euphorbia pulcherrima) in Venezuela

Plant Disease ◽  
2001 ◽  
Vol 85 (11) ◽  
pp. 1208-1208 ◽  
Author(s):  
O. Carballo ◽  
M. L. Izaguirre ◽  
E. Marys
Keyword(s):  
Mosaic Virus ◽  
Leaf Tissue ◽  
Enzyme Linked Immunosorbent Assay ◽  
Euphorbia Pulcherrima ◽  
Leaf Extracts ◽  
Thin Sections ◽  
Virus Particles ◽  
Transmission Electron ◽  
Rugose Mosaic ◽  
Infected Cells

Poinsettia mosaic virus (PnMV), a putative member of the tymoviruses, was detected in several cultivars of vegetatively propagated poinsettias grown in commercial nurseries in Estado Miranda, Venezuela. Symptoms associated with the affected plants consisted of severe mottling and distortion of leaves and bracteoles. The suspect virus was mechanically transmitted to Nicotiana benthamiana. Leaf extracts and thin sections of affected leaf tissue were analyzed by transmission electron microscopy. Spherical virus particles (30 nm diameter) were observed in samples from symptomatic poinsettia plants. Ultrastructural analyses of virus-infected cells revealed aggregates of virus particles in the cytoplasm and central vacuole. The virus was purified twice from infected N. benthamiana, resulting in yields as high as 12 mg/100 g. Dissociated coat protein contained a single 24-kDa protein species. The virus was not serologically related to Carnation mottle, Bean rugose mosaic, Cowpea mosaic, Cucumber mosaic, Pea enation mosaic, Prunus necrotic ringspot, Apple mosaic, Tobacco streak, Maize rayado fino, Tomato ringspot, Bean southern mosaic, Sowbane mosaic, Andean potato latent, Belladona mottle, Scrophularia or Turnip yellow mosaic viruses, but did react positively in enzyme-linked immunosorbent assay and western blot analysis with antiserum (ATCC PVAS-476) to PnMV. Based on these results, the virus is considered to be PnMV. To our knowledge, this is the first report of PnMV infecting poinsettias in Venezuela.

The application of ultracryotomy in the study of the fine structure of intracellular virus particles: mouse mammary tumor virus (MMTV)

1978 ◽  
Vol 36 (2) ◽  
pp. 366-367
Author(s):  
T. Hanaichi ◽  
M. Hoshino ◽  
S. Nakamura ◽  
Y. Nishi ◽  
M. Imai ◽  
...  
Keyword(s):  
Negative Staining ◽  
Cell Organelles ◽  
Mammary Tumor Virus ◽  
Thin Sections ◽  
Virus Particles ◽  
The Past ◽  
Mouse Mammary Tumor ◽  
Tumor Virus ◽  
Infected Cells ◽  
Intracellular Virus

For the electron microscopy of intracellular virus particles, two techniques have mainly been used; thin sections of plastic- embedded, virus-infected cells and negative staining of the virus particles isolated by disrupting the infected cells. For the observation of minute structures of the particles at high magnification, the latter is often far superior to the former. However, the latter requires the destruction of relations of virus particles to the surrounding cell organelles and may result in the observation of the particles in a distorted state due to the loss of certain materials related to the virus during the isolation process. Ultracryotomy, developed for the past decade, takes advantage of the process of negative staining for the detection of complex intracellular structures at a high resolution. This led us to apply technique to the study of the virus-infected cells. This paper will report the detailed ultrastructures of MMTV at different stages of evolution in the infected cells as revealed by the ultracryotomy technique.

scholarly journals Identification of distinct steps during tubule formation by the movement protein of Cowpea mosaic virus

2003 ◽  
Vol 84 (12) ◽  
pp. 3485-3494 ◽  
Author(s):  
Jeroen Pouwels ◽  
Noortje Kornet ◽  
Nikkie van Bers ◽  
Teun Guighelaar ◽  
Jan van Lent ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Mosaic Virus ◽  
Movement Protein ◽  
Cell Movement ◽  
Cowpea Mosaic Virus ◽  
Tubule Formation ◽  
Virus Particles ◽  
Cell Localization ◽  
Support Cell ◽  
Infected Cells

The movement protein (MP) of Cowpea mosaic virus (CPMV) forms tubules through plasmodesmata in infected plants thus enabling virus particles to move from cell to cell. Localization studies of mutant MPs fused to GFP in protoplasts and plants identified several functional domains within the MP that are involved in distinct steps during tubule formation. Coinoculation experiments and the observation that one of the C-terminal deletion mutants accumulated uniformly in the plasma membrane suggest that dimeric or multimeric MP is first targeted to the plasma membrane. At the plasma membrane the MP quickly accumulates in peripheral punctuate spots, from which tubule formation is initiated. One of the mutant MPs formed tubules containing virus particles on protoplasts, but could not support cell-to-cell movement in plants. The observations that this mutant MP accumulated to a higher level in the cell than wt MP and did not accumulate in the cell wall opposite infected cells suggest that breakdown or disassembly of tubules in neighbouring, uninfected cells is required for cell-to-cell movement.

Ultrastructural changes in tomato infected with tomato leaf curl virus, a whitefly-transmitted geminivirus

1992 ◽  
Vol 70 (9) ◽  
pp. 1747-1753 ◽  
Author(s):  
Channarayappa Channarayappa ◽  
V. Muniyappa ◽  
D. Schwegler-Berry ◽  
G. Shivashankar
Keyword(s):  
Severe Form ◽  
Tomato Leaf ◽  
Ultrastructural Changes ◽  
Sieve Elements ◽  
Virus Particles ◽  
Tomato Leaf Curl Virus ◽  
20 Nm ◽  
Tomato Leaf Curl ◽  
Leaf Curl Virus ◽  
Leaf Curl

The ultrastructural modifications in nucleus of tomato infected with tomato leaf curl virus (TLCV) included hypertrophy of the nucleolus, segregation of nucleolar components into discrete granular and fibrillar regions, appearance of electron-dense particles associated ribbon-like structures, and presence of virus particles as either loosely compacted or hexagonally close-packed symmetrical arrays. The virus particles were isometric, about 18–20 nm in diameter. In the lumen of sieve elements, virus particles occasionally formed aggregates that were cylindrically arranged and occurred in pairs. Among the organelles other than the nucleus, virus particles were found in the plastids of sieve elements. In the chloroplasts of TLCV-infected cells, considerable disturbances in the internal organization were observed. In the most severe form of degeneration, the thylakoid system was fragmented and disorganized. In some chloroplasts starch grains were abnormally large. Excessive accumulation of osmiophilic bodies in degenerating chloroplasts was prominent. Key words: leaf curl virus, geminate particles, nucleolar hypertrophy, virus particles, osmiophilic body.

scholarly journals Assembly and Maturation of the Flavivirus Kunjin Virus Appear To Occur in the Rough Endoplasmic Reticulum and along the Secretory Pathway, Respectively

2001 ◽  
Vol 75 (22) ◽  
pp. 10787-10799 ◽  
Author(s):  
Jason M. Mackenzie ◽  
Edwin G. Westaway
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Rough Endoplasmic Reticulum ◽  
Envelope Protein ◽  
Secretory Pathway ◽  
Brefeldin A ◽  
Immunogold Labeling ◽  
Virus Particles ◽  
Infected Cells ◽  
Assembly Site

ABSTRACT The intracellular assembly site for flaviviruses in currently not known but is presumed to be located within the lumen of the rough endoplasmic reticulum (RER). Building on previous studies involving immunofluorescence (IF) and cryoimmunoelectron microscopy of Kunjin virus (KUN)-infected cells, we sought to identify the steps involved in the assembly and maturation of KUN. Thus, using antibodies directed against envelope protein E in IF analysis, we found the accumulation of E within regions coincident with the RER and endosomal compartments. Immunogold labeling of cryosections of infected cells indicated that E and minor envelope protein prM were localized to reticulum membranes continuous with KUN-induced convoluted membranes (CM) or paracrystalline arrays (PC) and that sometimes the RER contained immunogold-labeled virus particles. Both proteins were also observed to be labeled in membranes at the periphery of the induced CM or PC structures, but the latter were very seldom labeled internally. Utilizing drugs that inhibit protein and/or membrane traffic throughout the cell, we found that the secretion of KUN particles late in infection was significantly affected in the presence of brefeldin A and that the infectivity of secreted particles was severely affected in the presence of monensin and N-nonyl-deoxynojirimycin. Nocodazole did not appear to affect maturation, suggesting that microtubules play no role in assembly or maturation processes. Subsequently, we showed that the exit of intact virions from the RER involves the transport of individual virions within individual vesicles en route to the Golgi apparatus. The results suggest that the assembly of virions occurs within the lumen of the RER and that subsequent maturation occurs via the secretory pathway.

Sign in / Sign up

Export Citation Format

Share Document