Infection proliferation characteristics of N. bombycis. (A) TEM micrographs illustrating the N. bombycis life cycle in BmE-SWU1 cells. N, nucleus; C, cytoplasm; Sp, spore plasm; Sc, schizont; Sb, sporoblast; S, spore. (B) Immunofluorescence assays showing N. bombycis proliferation characteristics. BF, bright fluorescence; DAPI shows B. mori and N. bombycis nuclei; green fluorescence shows the NbTubulin proteins. (C) RT-PCR analysis of N. bombycis genomic DNA copies in BmE-SWU1 cells, based on Nb SSURNA copy numbers. All data represent means of three replicates ± SD. **, P < 0.01.