Submitted to: Journal of Eukaryotic Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2001
Publication Date: 7/1/2001
Citation: BOUCIAS, D., BECNEL, J.J., WHITE, S.E., BBOTT, M. IN VIVO AND IN VITRO DEVELOPMENT OF THE PROTIST HELICOSPORIDIUM SP.. JOURNAL OF EUKARYOTIC MICROBIOLOGY. 2001. Interpretive Summary: Naturally occurring protozoan parasites of insects are under study to evaluate and develop these disease causing organisms as biological control agents. A new species of Helicosporidia has been found in black flies in Florida. Helicosporida are known from a number of arthropods, but fundamental knowledge on their life cycles, modes of transmission and taxonomic placement are incomplete. In this investigation scientists from the University of Florida and the ARS, Center for Medical, Agricultural and Veterinary Entomology, in Gainesville, Florida have conducted molecular analysis of this Helicosporidium sp. and determined that it may represent a unique group of organisms.
Technical Abstract: We describe the discovery and developmental features of a Helicosporidium sp. isolated from the black fly Simulium jonesi. Morphologically, the helicosporidia are characterized by a distinct cyst stage that encloses three ovoid cells and a single elongate filamentous cell. Bioassays have demonstrated that the cysts of this isolate infect various insect species, including the lepidopterans, Helicoverpa zea, Galleria mellonella, and Manduca sexta, and the dipterans, Musca domestica, Aedes taeniorhynchus, Anopheles albimanus, and An. quadrimaculatus. The cysts attach to the insect peritrophic matrix prior to dehiscence, which releases the filamentous cell and the three ovoid cells. The ovoid cells are short-lived in the insect gut with infection mediated by the penetration of the filamentous cell into the host. Furthermore, these filamentous cells are covered with projections that anchor them to the midgut lining. Unlike most tentomopathogenic protozoa, this Helicosporidium sp. can be propagated in simple nutritional media under defined in vitro conditions, providing a system to conduct detailed analysis of the developmental biology of this poorly known taxon. The morphology and development of the in vitro produced cells are similar to that reported for the achorophyllic algae belonging to the genus Prototheca.