scholarly journals The size of encapsidated single-stranded DNA determines the multiplicity of African cassava mosaic virus particles

2001 ◽  
Vol 82 (3) ◽  
pp. 673-676 ◽  
Author(s):  
Thomas Frischmuth ◽  
Margit Ringel ◽  
Cornelia Kocher
Keyword(s):  
Electron Microscopy ◽  
Mosaic Virus ◽  
Nicotiana Benthamiana ◽  
Southern Blotting ◽  
African Cassava Mosaic Virus ◽  
Dna Virus ◽  
Virus Particles ◽  
20 Nm ◽  
And Control ◽  
Cassava Mosaic Virus

Transgenic Nicotiana benthamiana plants harbouring a defective interfering (DI) DNA of African cassava mosaic virus (ACMV) and control plants were inoculated with ACMV. Virus particles were purified from infected plants, separated in sucrose gradients and fractions were analysed by Southern blotting. Transgenic plant-derived virus particles taken from the top fractions of sucrose gradients contained DI DNA, middle fractions contained a mixture of genomic and DI DNA and bottom fractions contained a mixture of multimeric, genomic and DI DNA. Virus particles from selected top, middle and bottom fractions were analysed by electron microscopy. In fractions containing only DI DNA, isometric particles of 18–20 nm were detected. In fractions containing DI DNA as well as genomic size DNA, isometric and geminate particles were found. Fractions containing multimeric size DNA were found to comprise particles consisting of three subunits adjacent to geminate particles. From these data, it is concluded that the size of encapsidated DNA determines the multiplicity of ACMV particles.

scholarly journals Disassembly of African cassava mosaic virus

2008 ◽  
Vol 89 (8) ◽  
pp. 2029-2036 ◽  
Author(s):  
Katharina Kittelmann ◽  
Holger Jeske
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Nicotiana Benthamiana ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Complete Loss ◽  
African Cassava Mosaic Virus ◽  
Dna Release ◽  
Ph Range ◽  
Cassava Mosaic Virus

The plant-infecting geminiviruses encapsidate their single-stranded DNA genome in characteristic twinned particles that are unique among viruses. These particles are formed by joining two incomplete T=1 icosahedra. African cassava mosaic virions were purified by density-gradient centrifugation from infected Nicotiana benthamiana plants and analysed for their stability with respect to pH changes and heat treatment by using electron microscopy. Negative staining and rotary shadowing revealed stable virions as well as isolated capsomeres between pH 4.0 and 8.5. At pH 9.0 and above, particles disintegrated, whereas they mainly aggregated at a pH below 6.0. Heating the preparations to 55 °C and above resulted in the complete loss of any discernible structure. A low proportion (approx. 10 %) of particles ejected their DNA within the pH range of 6.0–8.5. Most virions released their DNA at the top (15.9 %) or the shoulder (71.4 %) of the twin particles and only 12.7 % at the waist. Compared with the expected numbers of pentameric capsomeres at the top (9 %), the shoulder (45.5 %) or the waist (45.5 %), the results revealed a preferential DNA release from the top and shoulder of the geminate particle.

Sign in / Sign up

Export Citation Format

Share Document