Nosema portugal, n. sp., isolated from gypsy moths (Lymantria dispar L.) collected in Portugal

A microsporidium Nosema portugal n. sp. was isolated from gypsy moths, Lyma ntria dispar L, collected near Lisbon, Portugal, in 1985. The Life cycle in cludes two sequential developmental cycles, a primary and a secondary cycle . The primary cycle occurs in midgut epithelial cells, where primary spores are produced within 48 h. The primary spores immediately extrude their pol ar filaments, presumably to infect other cells. In the target tissues (sali vary glands and fat body) the secondary development cycle is followed by th e formation of environmental spores. Primary spores were also sometimes pre sent in target tissues. Fresh unfixed and unstained primary spores have a l arge posterior vacuole and measured 4.8 x 2.7 mu m. Ultrastructurally, they have 5-8 polar filament coils, a large posterior vacuole, abundant endopla smic reticulum, and were binucleate. Mature unfixed and unstained environme ntal spores were highly refractive and the posterior vacuole and nuclei cou ld not be seen through the spore coat. Fresh environmental spores measured 4.5 x 1.9 mu m. Ultrastructurally, environmental spores were binucleate, wi th a typical polaroplast, 10-11 isofilar polar filament coils, and a series of 4-6 thin polar filament-like tubules situated at the posterior end of t he row of typical polar filament coils. The ssu rRNA sequences strongly sug gest that this species is more closely related to the Vairimorpha subgroup within the Nosema/Vairimorpha clade than to the Nosema subgroup. (C) 1999 A cademic Press.