Biology Reference
In-Depth Information
mild mosaic symptoms. BMV is transmitted by nematodes and can be found
in the USA and in Europe (from DPV; http://www.dpvweb.net and the ICTV;
http://www.ncbi.nlm.nih.gov/ICTVdb).
BMV particles have icosahedral symmetry with a diameter of about 28
nm; the structure has been solved by X-ray crystallography (Lucas
.,
2002). The capsid is composed of 180 identical copies of a single coat protein
arranged in
et al
= 3 symmetry. The genome is positive-sense, single-stranded,
and tripartite, meaning that the genetic information is encoded on three
different RNA molecules (Ahlquist
T
., 1981, 1984).
BMV particles are typically propagated in barley plants (
et al
Hordeum
vulgare
). Yields in gram scales can be obtained from 1 kg of infected leaf
material. A heterologous expression system in yeast (
Saccharomyces
cerevisiae
) has also been developed that allows high yield production of
virus-like particles (VLP) (reviewed in Schneemann & Young, 2003). A VLP
is a particle that is produced in a non-natural host. VLPs do not contain
genomic information; the particles either are empty or pack random cellular
RNA. VLPs are of interest in nanotechnology because they do not contain
genetic information, and they are non-infectious and considered safe from
an agricultural and human health perspective. The different expression
systems and their advantages will be described further in Chapter 3.
Besides the ability to produce empty BMV VLPs in a heterologous
expression system, coat protein monomers can also be assembled
in vitro
into
intact VLPs (Pfeiffer
., 1976; Pfeiffer & Hirth, 1974). These characteristics
have led to the development of BMV as a platform for the encapsulation of
synthetic materials such as gold nanoparticles and quantum dots (QDs)
(Chen
et al
., 2007)
(described earlier in this chapter and discussed in detail in Chapter 5).
et al
., 2006; Dixit
et al
., 2006; Dragnea
et al
., 2003; Sun
et al
..
Cowpea Chloroic Motle Virus
: A Plant Virus
CCMV, like BMV, belongs to the family
, which is reflected by
a range of similarities in structure and genome organization. CCMV infects
mostly legumes and causes disease in black-eyed peas as well as in soybeans.
The virus is found exclusively in the United States of America where it is
transmitted by beetles (from DPV; http://www.dpvweb.net).
CCMV forms particles with a diameter of about 30 nm. The CCMV capsid
is composed of 180 identical copies of a single coat protein arranged in a
T
Bromoviridae
= 3 symmetry. The structure of the particles has been determined by X-ray
crystallography (Speir
., 1995). The genome is a tripartite, positive-sense,
single-stranded RNA genome.
et al
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