Filamentous Virus-like Particles Research Articles

Association of Double-stranded RNA and Filamentous Viruslike Particles with Dodonaea Yellows Disease

Dodonaea viscosa in the Hawaiian Islands is affected by a severe yellowing disease with symptoms resembling those of diseases caused by mycoplasmalike organisms in other woody hosts. Double stranded RNA with an estimated molecular weight of 3×10 6 was detected in plants displaying disease symptoms but not in asymptomatic plants. Viruslike particles 16 nm in diameter and 700 nm in modal length were also isolated from diseased plants but were not present in extracts of healthy plants

Structure of the nucleocapsid of a filamentous virus of the honey bee ( Apis mellifera)

Filamentous virus-like particles were isolated from bees showing the signs and symptoms of bee rickettsiosis. The structure of the nucleocapsid of these particles was studied at the electron microscopic level. The axes of the virus-like particle measured 450 × 170 nm and the dimensions of the single coiled nucleocapsid were 3150 × 40 nm. The nucleocapsids, in their normal arrangement, reveal the appearance of a figure 8. It is proposed, based on the dimensions of both the particle and the nucleocapsid as well as on the ellipsoidal shape of the particle, that the nucleocapsid, in order to fit into the envelope, has to form three 8's.

Virus-Like Particles and a Spider Mite Intimately Associated with a New Disease of Barley

The malting barley-producing regions in Montana and Canada are threatened with a new virus-like barley disease that appears to be etiologically novel. Ultrathin sections of diseased tissue contained enveloped, filamentous virus-like particles that measured 64 nanometers by 126 to 4000 nanometers. These lengths are unique for plant viruses. Unexpectedly, the spider mite,Petrobia latens, which has never been reported to be a vector of a pathogen, was found to transmit the causal agent from diseased plants to healthy barley, while noninfective mites failed to do so unless they were allowed prior access to diseased tissue.

Nonoccluded baculovirus- and filamentous virus-like particles in the spotted cucumber beetle, diabrotica undecimpunctata (coleoptera: chrysomelid)

Nonoccluded baculovirus-and filamentous virus-like particles were found in nuclei of hemocytes or midgut cells of field-collected spotted cucumber beetles. Each type of particle was associated with a different type of virogenic stroma containing various viral components similar to those referred to as capsid, nucleocapsid, viroplasm, and viral envelope in other known baculovirus infections. Nucleocapsids of the virus which occured only in hemocytes were rod-shaped particles approximately 230 nm long and 52 nm wide and were enveloped singly by a trilaminar unit membrane. Enveloped and partly enveloped particles appeared to be released from the nucleus to the cytoplasm by budding through the nuclear envelope acquiring additional membranes. The nucleocapsids of the virus which occurred only in nuclei of midgut cells were filamentous particles with an average diameter of 25 nm and variable length up to 2 μm. Some extremely long particles were bent almost 360° near the middle, resulting in a hairpin-like configuration. The particles were always enveloped singly. No particles budding through the nuclear envelope were observed.

Isolation and properties of filamentous viruslike particles associated with little cherry disease in Prunus avium

Filamentous viruslike particles (VLP) associated with little cherry disease were purified directly from leaves of naturally infected field-grown and graft-inoculated, greenhouse-grown sweet cherry trees. A procedure was developed which effectively released the VLP from the phloem elements and simultaneously protected them against the denaturing and interfering agents known to become increasingly more abundant in the leaves as the season progresses. Milk was selected as the extraction medium because of its excellent protection against tannins and polyphenol oxydase and mucoid action. Milk extracts were clarified by filtration after addition of 20% (NH4)2SO4. VLP were isolated by differential centrifugation and further purified by polyethylene glycol precipitation. Electron microscopy of negatively stained preparations revealed very flexuous particles with a characteristically open, electron-transparent outer helix with pitch 4.25 nm and a prominent opaque central core. Particles had a constant width of 10.6 nm, a dominant length around 1.5 μm, and possibly a second major length category around 1.8 μm. Purified particles were very stable. They had an isoelectric point of about 4.25, degraded at 80–85 °C, fragmented at room temperature in 2% sodium dodecyl sulfate, and when denatured in urea were vulnerable to proteinase K. Levels of VLP in situ were always very low. Purified preparations from good source material contained not more than 30 μg VLP/mL.

Antiviral activity of virus-like particles fromLentinus edodes (Shiitake)

Interferon (IF) induction and antiviral activity by purified spherical (S) or filamentous (F) virus-like particles and S-derived RNA was studied. A single administration of S particles prior to virus challenge reduced significantly the mortality of mice infected with western equine encephalitis (WEE) virus.

Filamentous viruslike particles in honey bees in Britain

Filamentous viruslike particles in honey bees in Britain

Filamentous and polyhedral virus-like particles in Boletus edulis

In the north-east and east of the Netherlands a disease ofBoletus edulis was noticed. Symptoms are described. The name ‘little-cap disease’ is proposed. In all cell-free preparations made from diseased, but also from healthy carpophores polyhedral virus-like particles about 33 nm and 42 nm in diameter were observed, the 33 nm particles prevailing. Occasionally a few polyheral particles of about 28 nm were isolated from healthy and diseased carpophores. Some healthy and diseased mushroom samples yielded filamentous virus-like particles about 500 nm long and 13 nm wide, with an axial canal. To our knowledge no other filamentous virus-like particles have been isolated from fungi so far. The role of the virus-like particles inB. edulis and the cause of ‘little-cap disease’ are still unknown. In het noordoosten en het oosten van Nederland werd een ziekte waargenomen in eekhoorntjesbrood,Boletus edulis, waarvan de symptomen worden beschreven. Naar het meest karakteristieke symptoom wordt de naam ‘kleine-hoedjesziekte’ voorgesteld. Aangezien een analoog ziektebeeld voorkomt bij viruszieke champignons en ook beschreven is voor enkele wilde paddestoelen, die waarschijnlijk virusziek zijn, werden zieke boleten onderzocht op de aanwezigheid van virus. In celvrije preparaten van zieke, maar ook van gezonde boleten werden steeds veelvlakkige virusachtige deeltjes gevonden met doorsneden van 33 en 42 nm; de 33 nm-deeltjes waren het talrijkste. Af en toe werden uit gezond en ziek materiaal weinige veelvlakkige deeltjes van 28 nm geisoleerd. Enkele monsters van gezonde zowel als van zieke boleten, leverden preparaten op met draadvormige deeltjes van ongeveer 500 nm lang en 13 nm dik, voorzien van een centrale holte. De betekenis van de virusachtige deeltjes inB. edulis en de oorzaak van de ‘kleine-hoedjesziekte’ zijn nog duister. Uit schimmels werden nog niet eerder draadvormige virusachtige deeltjes geisoleerd. De draadvormige deeltjes uitB. edulis vertonen uiterlijk overeenkomst met virussen uit de aardappelvirus X-groep (Potexvirus groep).

Virus like Particles in a Human Lung Tumor

Ultrastructural studies of pulmonary needle biopsies from patients with alveolar cell carcinoma (ACC) revealed the presence of a virus-like material in the nucleus and cytoplasm of tumor cells. Stinson et. al. reported the presence of filamentous virus-like particles in four of six cases in an ultrastructural study of ACC. In vitro studies by Coalson et. al. confirmed the presence of a biological agent and demonstrated that cell-free supernate from tumor cell cultures could induce cytopathic effect when applied to indicator cell lines. It was also shown in this report that tumor cell lines derived from this tumor produced the filterable biological agent until the 18-20 passage in culture. An extension of this investigation on the cell lines derived from ACC demonstrated that a unique antigen was associated with ACC tumor cells and that this antigenicity could be induced in indicator cell lines following treatment with cell free extracts.