|Van Der Wilk, Francis|
Submitted to: Archives of Virology
Publication Type: Book / Chapter
Publication Acceptance Date: 1/22/1999
Publication Date: N/A
Interpretive Summary: Viruses are common pathogens of all living organisms. However, little is known about the viruses that infect insects. In this chapter, a description of a newly characterized group of insect viruses is presented. Most of the viruses in this group, the cricket paralysis-like genus, are highly specialized and each infects a unique set of closely related insects. None have been reported to infect vertebrate animals. Likely because of their specialized adaptation to insect hosts, viruses with these characteristics have not been previously reported. The viruses are most similar to the group of animal viruses that includes the common cold virus. Because most cricket paralysis-like viruses are restricted to insect hosts, they are candidates for use as biological control agents for insect pests. The description published here will be useful to scientists who are studying insect pests and pathogens or who want to identify potential biological control agents that could be used as part of an integrated pest management program.
Technical Abstract: All members of the cricket paralysis-like genus have been isolated from invertebrate species. With the exception of cricket paralysis virus (CrPV), all members appear to have relatively restricted host ranges and have been isolated from hosts in only a single order. Transmission can be by horizontal (per os) or vertical routes. No vectors are known to be involved in transmission. Virions are roughly spherical with a particle diameter of approximately 30nm and no envelope. The virions exhibit icosahedral symmetry (T=3). Virions have a buoyant density in CsCl of between 1.34 and 1.37g/cm-2 and sedimentation coefficients of between 153 and 167 S. For those species where physicochemical stability has been assessed (CrPV) the virions are stable at pH 3.0. Particles contain a single molecule of linear, positive sense, ss RNA of approximately 9.5kb in size. The 3' end of the viral RNA is polyadenylated and in most species there is a protein, VPg, covalently linked to the 5' end of the genome. Mature virions contain three major structural proteins with Mr of 28-37 x10+3. In some species a fourth smaller structural protein (Mr = 4.5-9 x10+3) protein has been reported. In most species a minor structural component - larger than the major capsid proteins - has also been reported and is presumed to be the pre-cursor of one of the major structural proteins.