Virus-like particles in the poison gland of the parasitic wasp Opius concolor

Abstract

Virus-like particles (VLP's) have been found in the poison glands of adult females of the parasitic wasp Opius concolor Szepl. (Hymenoptera, Braconidae). These VLP's are found in the secretory cells either free in the cytoplasm or within cytoplasmic vesicles, sometimes associated to a secretory apparatus. Negative staining of these VLP's has revealed the occurrence of two different particles. The first type exhibits icosahedral symmetry (diameter around 70 nm) and hollow surface spikes, this morphology being typical of the genus Cypovirus (Reoviridae). The other type is pleomorphic and presents an envelope with club-shaped projections (diameter ranging from 30 to 60 nm), as classical textbook examples of Coronaviruses, but smaller. Function and full characterisation of these particles are not yet known.