Detection of aphid lethal paralysis virus in ultrathin sections of Rhopalosiphum padi aphids by immunogold labeling

Abstract

The technique of immunogold labeling was examined to detect the presence of aphid lethal paralysis virus (ALPV) in tissues of naturally infected aphids. Protein-gold complexes with gold particles were prepared with anti-ALPV-immunoglobulins (anti-ALPV-IgG) and goat antirabbit-immunoglobulin (GAR-IgG) fractions, respectively. The products were stored at 4°C for 2 months without a loss of activity. The complexes were used in dilution series of purified ALPV to show optimization of binding of labeled complexes in direct and indirect labeling experiments. The direct labeling of virion particles in purified virus preparations was more convincing than the indirect system. For ultrathin sections, the indirect method was more successful. The ultrastructure of aphids was well preserved in Spurr's resin for ultrathin sectioning. Methods utilized and adapted to label ultrathin sections with the indirect method were compared. The presence of virions and sites of high and low concentrations of virions in various tissues were also compared.