5-Bromodeoxyuridine-induced formation of virus-like particles in Naegleria gruberi EGs

Exposure of axenic cultures of the amoeboflagellate Naegleria gruberi EGs to the thymidine analogue 5-bromo-2'-deoxyuridine (BrdU) resulted in the induction of virus-like particles (VLP) and various structures associated with their development and presumed transmission. Previously, VLP induction could be accomplished only by growing amoebae in the presence of living bacteria as a food source. Addition of excess thymidine along with BrdU did not block induction of particles. This account demonstrates that the EGs-VLP system responded to BrdU as do a number of mammalian cell lines harbouring latent viruses, and provides the basis for future work on the infectivity of the VLPs for other amoebae as well as tissue culture cells.