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.

ELECTRON MICROSCOPY OF TWO SMALL SPHERICAL PLANT VIRUSES IN THIN SECTIONS

1966 ◽  
Vol 44 (6) ◽  
pp. 821-826 ◽  
Author(s):  
J. R. Edwardson ◽  
D. E. Purcifull ◽  
R. G. Christie
Keyword(s):  
Electron Microscopy ◽  
Mosaic Virus ◽  
Leaf Tissue ◽  
Plant Viruses ◽  
Tobacco Necrosis Virus ◽  
Necrosis Virus ◽  
Thin Sections ◽  
Virus Particles ◽  
Southern Bean Mosaic Virus

Particles within lesions of leaf tissue infected with either tobacco necrosis virus (TNV) or southern bean mosaic virus (SBMV) were compared with particles in embedded pellets of purified preparations of these viruses by an examination of thin sections. The mode of the diameters of particles in tissues and pellets was 20.5 mµ.It is assumed that the particles in infected tissues are virus particles on the basis of their similarities in size, shape, and arrangement with the particles in purified preparations.

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.

Some ultrastructural aspects of the pollen transmission of barley stripe mosaic virus in barley

1986 ◽  
Vol 64 (4) ◽  
pp. 853-858 ◽  
Author(s):  
Ronald H. Brlansky ◽  
Thomas W. Carroll ◽  
Susan K. Zaske
Keyword(s):  
Pollen Tube ◽  
Mosaic Virus ◽  
Developmental Stages ◽  
Ovary Wall ◽  
Barley Stripe Mosaic Virus ◽  
Thin Sections ◽  
Virus Particles ◽  
Pollen Transmission ◽  
Transmission Electron ◽  
Particle Form

To study the pollen transmission of barley stripe mosaic virus (BSMV) in barley with the transmission electron microscope, ultrathin sections of ovaries of pollinated pistils were examined. Healthy pistils were cross-pollinated with virus-infected pollen and collected at various intervals of time after pollination. When thin sections of the ovaries were viewed, virus particles were detected in specific sporophytic and gametophytic cells during critical developmental stages of pollination, fertilization, and embryogenesis. Before fertilization, BSMV particles were seen in the pollen tube between the integument and ovary wall, and in pollen tube discharge within the degenerating synergid. During and after fertilization, virus particles were found not only in the pollen tube and its discharge but also in the zygote, endosperm, persistent synergid, and nucellus. During embryogenesis, BSMV particles were very evident in the embryo, integument, and ovary wall. Some particles were scattered throughout the cell cytoplasm, while others were in mono- or multi-layer aggregates within the cytoplasm. Many particles were associated with spindle or cytoplasmic microtubules or with abnormal plastids. The prevalence of virus particles in the cells associated with sexual reproduction suggests that the nucleoprotein particle form of the virus plays some role in the pollen transmission of BSMV in barley.

Studies of a Defective Measles Virus

1968 ◽  
Vol 26 ◽  
pp. 208-209
Author(s):  
R. M. McCombs ◽  
M. Benyesh-Melnick ◽  
J. P. Brunschwig
Keyword(s):  
Inclusion Bodies ◽  
Measles Virus ◽  
Giant Cells ◽  
Helical Structures ◽  
Thin Sections ◽  
Virus Particles ◽  
Extracellular Virus ◽  
Culture Cells ◽  
Infected Cells ◽  
Eosinophilic Inclusions

Measles virus is an agent that is capable of replicating in a number of different culture cells and generally causes the formation of multinucleated giant cells. As a result of infection, virus is released from the cells into the culture fluids and reinfection can be initiated by this cell-free virus. The extracellular virus has been examined by negative staining with phosphotungstic acid and has been shown to be a rather pleomorphic particle with a diameter of about 140 mμ. However, no such virus particles have been detected in thin sections of the infected cells. Rather, the only virus-induced structures present in the giant cells are eosinophilic inclusions (intracytoplasmic or intranuclear). These inclusion bodies have been shown to contain helical structures, resembling the nucleocapsid observed in negatively stained preparations.

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 Unusual Long-Distance Movement Strategies of Potato mop-top virus RNAs in Nicotiana benthamiana

2009 ◽  
Vol 22 (4) ◽  
pp. 381-390 ◽  
Author(s):  
Lesley Torrance ◽  
Nina I. Lukhovitskaya ◽  
Mikhail V. Schepetilnikov ◽  
Graham H. Cowan ◽  
Angelika Ziegler ◽  
...  
Keyword(s):  
Capsid Proteins ◽  
Enzyme Linked Immunosorbent Assay ◽  
Leaf Extracts ◽  
Long Distance ◽  
Particle Assembly ◽  
Virus Particles ◽  
Systemic Movement ◽  
Translational Readthrough ◽  
Potato Mop Top Virus ◽  
Long Distance Movement

The Potato mop-top virus (PMTV) genome encodes replicase, movement, and capsid proteins on three different RNA species that are encapsidated within tubular rod-shaped particles. Previously, we showed that the protein produced on translational readthrough (RT) of the coat protein (CP) gene, CP-RT, is associated with one extremity of the virus particles, and that the two RNAs encoding replicase and movement proteins can move long distance in the absence of the third RNA (RNA-CP) that encodes the capsid proteins, CP and CP-RT. Here, we examined the roles of the CP and CP-RT proteins on RNA movement using infectious clones carrying mutations in the CP and CP-RT coding domains. The results showed that, in infections established with mutant RNA-CP expressing CP together with truncated CP-RT, systemic movement of the mutant RNA-CP was inhibited but not the movement of the other two RNAs. Furthermore, RNA-CP long-distance movement was inhibited in a mutant clone expressing only CP in the absence of the CP-RT polypeptide. CP-RT was not necessary for particle assembly because virions were observed in leaf extracts infected with the CP-RT deletion mutants. RNA-CP moved long distance when protein expression was suppressed completely or when CP expression was suppressed so that only CP-RT or truncated CP-RT was expressed. CP-RT but not CP interacted with the movement protein TGB1 in the yeast two-hybrid system. CP-RT and TGB1 were detected by enzyme-linked immunosorbent assay in virus particles and the long-distance movement of RNA-CP was correlated with expression of CP-RT that interacted with TGB1; mutant RNA-CP expressing truncated CP-RT proteins that did not interact with TGB1 formed virions but did not move to upper noninoculated leaves. The results indicate that PMTV RNA-CP can move long distance in two distinct forms: either as a viral ribonucleoprotein complex or as particles that are most likely associated with CP-RT and TGB1.

Ultrastructure of the Infection of Poinsettia by Oidium SP. using High Pressure Freezing and Freeze Substitution

2000 ◽  
Vol 6 (S2) ◽  
pp. 690-691
Author(s):  
G. J. Celio ◽  
E. A. Richardson ◽  
C. W. Mims
Keyword(s):  
High Pressure ◽  
Freeze Substitution ◽  
Uranyl Acetate ◽  
Euphorbia Pulcherrima ◽  
High Pressure Freezing ◽  
Thin Sections ◽  
Transmission Electron ◽  
Dextran Solution ◽  
Leaf Disks ◽  
Diamond Knife

Cryofixation is becoming more widely used to study host-pathogen relationships in fungal diseases of plants. This presentation describes results we have obtained using high pressure freezing and freeze substitution to study powdery mildew disease of poinsettia ﹛Euphorbia pulcherrima) caused by Oidium sp.Approximately 0.5 mm leaf disks bearing sporulating colonies of Oidium sp. were excised and placed in a 15% dextran solution contained in brass planchets. Samples were frozen using a Balzer's HPM 010 High Pressure Freezing Machine and substituted according to the procedures of Hoch.6 Thin sections of embedded leaves were cut using a diamond knife, collected on gold slot grids, and placed on formvar-coated racks. Sections were poststained with uranyl acetate and lead citrate and examined using a Zeiss EM 902A transmission electron microscope.Outstanding preservation of haustoria, the specialized nutrient-absorbing structures produced in host epidermal cells by Oidium, was obtained. Both young, unlobed (Fig. 1) as well as mature, highly lobed (Fig. 2) haustoria were observed.

An enzyme-linked immunosorbent assay for the detection of apple mosaic virus in yellow birch

1980 ◽  
Vol 10 (3) ◽  
pp. 278-283 ◽  
Author(s):  
T. Hardcastle ◽  
A. R. Gotlieb
Keyword(s):  
Mosaic Virus ◽  
Immunosorbent Assay ◽  
Leaf Tissue ◽  
Enzyme Linked Immunosorbent Assay ◽  
Elisa Method ◽  
Yellow Birch ◽  
Field Samples

An enzyme-linked immunosorbent assay (ELISA) method was developed to detect apple mosaic virus (ApMV) in Betulaalleghaniensis Britton. Tests for virus using bark and bud tissues of dormant trees were successful. ApMV was also detectable in old leaf tissue in August and September, as well as in newly emerging leaf tissue forced in a greenhouse in March. Whole crude antiserum used to coat ELISA plates in tests with bud tissues was a reliable substitute for purified immunoglobulin without loss of sensitivity or specificity. An attempt was made to use ELISA for quantifying virus concentrations in field samples of ApMV-infected birch leaves.

Investigations on the nature of a graft-transmissible agent in poinsettia

1993 ◽  
Vol 71 (8) ◽  
pp. 1097-1101 ◽  
Author(s):  
John M. Dole ◽  
Harold F. Wilkins ◽  
Sharon L. Desborough
Keyword(s):  
Mosaic Virus ◽  
Gel Electrophoresis ◽  
Leaf Morphology ◽  
Rna Viruses ◽  
Polyacrylamide Gel Electrophoresis ◽  
Euphorbia Pulcherrima ◽  
Branching Pattern ◽  
Banding Patterns ◽  
Double Stranded Rna ◽  
Transmission Electron

The free-branching poinsettia (Euphorbia pulcherrima) cultivar Annette Hegg Brilliant Diamond contains a free-branching agent that is graft-transmissible to the restricted-branching cultivar Eckespoint C-1 Red. Transmission electron microscopy failed to reveal evidence of bacteria, fungi, or mycoplasma-like organisms in either 'Brilliant Diamond' or 'C-1 Red' plants. Treatment of both cultivars with tetracycline-hydrochloride produced no differences in branching pattern or leaf morphology in either cultivar, indicating that the agent may not be a mycoplasma-like organism. Scions of a poinsettia mosaic virus indicator species (Euphorbia cyathophora) grafted onto 'Brilliant Diamond' and 'C-1 Red' stocks exhibited the mottling symptoms characteristic of poinsettia mosaic virus, while self-grafted E. cyathophora scions showed no mottling, indicating that poinsettia mosaic virus was not the agent. The agent was not transmitted by pin prick, carborundum, or dodder (Cuscuta sp.), and ribaviran did not eliminate expression of the branching agent from 'Brilliant Diamond' plants. No differences in double-stranded RNA banding patterns were found between extracts of free- and restricted-branching poinsettias by polyacrylamide gel electrophoresis. The double-stranded RNA was attributed to poinsettia mosaic virus and other unknown RNA viruses. Attempts to detect a specific DNA associated with free-branching were inconclusive. Key words: branching agent, Euphorbia pulcherrima, graft transformation, dsRNA, poinsettia mosaic virus.

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