Structure of rotaviruses as studied by the freeze-drying technique

Roseto, A.; Escaig, J.; Delain, Etienne; Cohen, Jean; Scherrer, R.

doi:10.1016/0042-6822(79)90571-3

Cited by 48 publications

(39 citation statements)

References 11 publications

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“…A characteristic feature of the virion is the 'double-shell' and virus particles when examined by electron microscopy appear either 'complete', 70 to 75 nm in diameter, or somewhat smaller with the outer shell missing. The virus particle has icosahedral symmetry but according to the few reports on its structure there is little agreement on the number and arrangement of subunits in the capsid (Martin et al, 1975;Palmer et al, 1977;Stannard & Schoub, l 977;Esparza & Gil, 1978 ;Kogasaka et al, 1979;Roseto et al, 1979).…”

Section: Introductionmentioning

confidence: 99%

Electron Microscopy of Tubular Assemblies Associated with Naturally Occurring Bovine Rotavirus

Chasey¹,

Labram²

1983

Journal of General Virology

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Section: Introductionmentioning

confidence: 99%

Electron Microscopy of Tubular Assemblies Associated with Naturally Occurring Bovine Rotavirus

Chasey¹,

Labram²

1983

Journal of General Virology

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“…The structure of the rotavirus particle has been the subject of several investigations, resulting in a number of conflicting interpretations (Martin et al, 1975;Stannard & Schoub, 1977;Esparza & G il, 1978;Kogasaka et al, 1979;Roseto et al, 1979). Martin et al (1975) initially reported that the surface of human rotavirus particles was composed of 32 large capsomeres with a structure similar to that presently accepted for the orbiviruses.…”

Section: Introductionmentioning

confidence: 99%

Biochemical Evidence for the Oligomeric (Possibly Trimeric) Structure of the Major Inner Capsid Polypeptide (45K) of Rotaviruses

Gorziglia

Larrea

Liprandi

et al. 1985

Journal of General Virology

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SUMMARYThe major structural polypeptide of rotaviruses is p45K (VP6), which forms the morphological subunit of the inner capsid. Such subunits show a trimeric structure when examined with the electron microscope. Treatment of single-capsid rotavirus particles with 1.5 M-CaCI~ removes p45K, resulting in the generation of smooth cores. Sucrose density gradient centrifugation analysis of the removed p45K revealed that it has a sedimentation coefficient close to 7.3S, compatible with an oligomeric (possibly trimeric) structure. Polyacrylamide gel electrophoresis under reducing or non-reducing conditions indicated that p45K has intramolecular but not intermolecular disulphide bonds, suggesting that interactions between p45K monomers may be due to some other type of association, such as hydrophobic or charge interactions. Velocity sedimentation of infected cell extracts revealed that native p45K also behaves as an oligomeric protein. Such results were confirmed using p45K partially purified by DEAE-cellulose chromatography. The evidence obtained indicated that all p45K present in the virion is in the oligomerie form, not associated by disulphide bonding, and that most native p45K present in the infected cells is also in the oligomeric form, probably as a consequence of early protein-protein interaction in rotavirus morphogenesis.

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“…The freeze-drying technique we employed to examine BECV offers some advantages over negative staining, especially as particles seem to be better preserved with regard to shape and size, and since single-sided images can be obtained instead of superimposed ones (Roseto et al, 1979). In this context, the most interesting observations made in this study are related to the shape and size of the virus particles themselves, and to the structure of the bulbous projections.…”

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confidence: 77%

Section: Discussionmentioning

confidence: 99%

“…The refractive index of the fractions was read with a Zeiss refractometer. Rotavirus particles, used in some experiments as controls, were obtained and purified as previously described (Roseto et al, 1979).Purified virus particles were placed on to collodion-coated grids for a few minutes and then washed in 0-1 M-ammonium acetate buffer pH 6-2, excess buffer was blotted and the grids were immediately dipped in nitrogen slush (-210 °C). They were then clamped in a copper specimen holder immersed in liquid nitrogen and transferred to the vacuum chamber of a Reichert cryofract apparatus (Escaig & Nicolas, 1976).…”

mentioning

confidence: 99%

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Bovine Enteric Coronavirus Structure as Studied by a Freeze-drying Technique

Roseto

Bobulesco

Laporte

et al. 1982

Journal of General Virology

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SUMMARYA strain of bovine coronavirus (F 15) was studied by electron microscopy using a freeze-drying technique. Purified coronavirus preparations show three different categories of image: (i) 'blackberry-like' virions, (ii) virions with a smooth depression at their surface, and (iii) apparently broken particles showing very clearly the areas of spike insertion in the virus membrane. Virus projections resemble 'mushrooms' with the 'stalk' inserted at the virus membrane. A model of the virion structure is proposed.Coronaviruses are a group of enveloped RNA-containing viruses that have a unique, typical morphology. They cause a variety of diseases in animals, including avian infectious bronchitis, feline infectious peritonitis, mouse hepatitis, transmissible gastroenteritis in pigs, and diarrhoea in young calves. In humans, they are responsible for some respiratory diseases and acute enterocolitis (for review, see Tyrrell et al., 1975).Coronavirus virions have usually been described, after negative staining, as large pleomorphic particles showing characteristic bulbous projections which form a corona around the virus core (Robb & Bond, 1979). Several measurements have revealed a range in total diameter of the virions from 70 nm to 200 nm. The surface projections have been observed to vary in shape and size, although the length is normally between 12 nm and 25 nm, and usually form a single fringe radiating from the virus core in all coronaviruses with the exception of bovine enteric coronavirus (BECV) and diarrhoea virus of infant mice (Sugiyana & Amano, 1981), where two layers of projections have been described (Caul & Egglestone, 1977;Robb & Bond, 1979). The distal ends of the spikes are clearly visible on the micrographs but the tails are only occasionally seen.Although negative staining has permitted some critical analysis of these viruses, uncertainty remains with respect to some details of their ultrastructure, especially regarding the real morphology of the projections and the relationship between the projections and the virus surface. Nermut & Franck (1971) have proved that with the freeze-drying method the size and architecture of enveloped viruses can be established with precision. In the present study we used this technique to define some of the uncertain morphological aspects of BECV virions, and on the basis of a more accurate and reproducible image of the virus particles, we propose a model based on our observations. BECV, strain F15, was grown in HRT 18 cells as previously described (Laporte et al., 1980; Laporte & Bobulesco, 1981). Virus was purified on a 20 to 45 ~o (w/w) sucrose gradient (Beckman SW27 rotor for 90 min at 45 000 rev/min, 4 °C). The virus band was collected and pelleted after dilution in water (Beckman SW25 rotor for 90 min at 45 000 rev/min, 4 °C). The pellet was resuspended in distilled water and layered on to a 20 to 60~ (w/w) sucrose gradient (Beckman SW27 rotor for 17 h at 25 000 rev/min). Gradient fractions were collected and absorbance at 254 nm measured (ISCO U.A.5 density ...

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Structure of rotaviruses as studied by the freeze-drying technique

Cited by 48 publications

References 11 publications

Electron Microscopy of Tubular Assemblies Associated with Naturally Occurring Bovine Rotavirus

Electron Microscopy of Tubular Assemblies Associated with Naturally Occurring Bovine Rotavirus

Biochemical Evidence for the Oligomeric (Possibly Trimeric) Structure of the Major Inner Capsid Polypeptide (45K) of Rotaviruses

Bovine Enteric Coronavirus Structure as Studied by a Freeze-drying Technique

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