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Xu X.,Jiangsu University of Science and Technology | Shen Z.,Jiangsu University of Science and Technology | Shen Z.,Chinese Academy of Agricultural Sciences | Shen Z.,Key Laboratory of Genetic Improvement of Silkworm | And 6 more authors.
Parasitology Research | Year: 2012

This study examined the morphological and molecular characteristics of the microsporidium Endoreticulatus sp. Zhenjiang, isolated from the silkworm (Bombyx mori). The fresh spores were oval, 2.9±0.2 μm in length and 1.2±0.2 μm in width. The complete rRNA cistron has a length of 4,432 bp (GenBank accession no. FJ772431), including the large subunit rRNA (2,460 bp), the internal transcribed spacer (187 bp), the small subunit rRNA (1,254 bp), the intergenic spacer (276 bp), and the 5S region (115 bp). The organization of the rRNA gene is 5'- LSU-ITS-SSU-IGS-5S-3', which is reverse compared to the organization of most microsporidian rRNA regions. Phylogenetic analysis based on small subunit rRNA sequences showed that this isolate belongs to the genus Endoreticulatus, and is closely related to Glugoides intestinalis. Furthermore, both had a similar reverse arrangement of the rRNA gene. Our study provides another example of a microsporidian species with a novel organization of rRNA genes, demonstrating that the reverse arrangement is exhibited not only by the microsporidian genus Nosema but may also occur in a clade that contains the genera Endoreticulatus and Glugoides. © Springer-Verlag 2011.

Chen D.,Jiangsu University of Science and Technology | Shen Z.,Jiangsu University of Science and Technology | Shen Z.,Chinese Academy of Agricultural Sciences | Shen Z.,Key Laboratory of Genetic Improvement of Silkworm | And 9 more authors.
Parasitology Research | Year: 2012

Cabbage butterfly (Pieris rapae), included in the Lepidoptera genus, Pieris family, is the main pest that damages Cruciferae. In this paper, we reported a microsporidian isolate of Nosema species which was isolated from P. rapae in Zhenjiang City, Jiangsu Province, China. The mature spore of this microsporidium is long oval in shape and 3.8∈±∈0.3 × 2.0∈±∈0.2 μm in size. Research results showed that the novel microsporidium cannot infect the BmN cell in vitro and silkworm larvae. The organization of rRNA gene was 5′-SSU rRNA-ITS-LSU rRNA-3′. Phylogenetic trees based on SSU rRNA and LSU rRNA gene sequences were constructed by MEGA 4.0 software. The topology showed that this microsporidium was on the same second branch of Nosema clade, and had close relationships to other Nosema species. Consequently, this microsporidium was confirmed to be a member of Nosema genus, and named as Nosema sp. MPr. © 2012 Springer-Verlag.

Yue Y.-J.,Jiangsu University of Science and Technology | Yue Y.-J.,Chinese Academy of Agricultural Sciences | Yue Y.-J.,Key Laboratory of Genetic Improvement of Silkworm | Tang X.-D.,Jiangsu University of Science and Technology | And 21 more authors.
Journal of Invertebrate Pathology | Year: 2015

Host-pathogen interactions are complex processes, which have been studied extensively in recent years. In insects, the midgut is a vital organ of digestion and nutrient absorption, and also serves as the first physiological and immune barrier against invading pathogenic microorganisms. Our focus is on Nosema bombycis, which is a pathogen of silkworm pebrine and causes great economic losses to the silk industry. A complete understanding of the host response to infection by N. bombycis and the interaction between them is necessary to prevent this disease. Silkworm midgut infected with N. bombycis is a good model to investigate the early host responses to microsporidia infection and the interaction between the silkworm and the microsporidium. Using Digital Gene Expression analysis, we investigated the midgut transcriptome profile of P50 silkworm larvae orally inoculated with N. bombycis. At 6, 12, 18, 24, 48, 72, and 96. h post-infection (hpi), 247, 95, 168, 450, 89, 80, and 773 DEGs were identified, respectively. KEGG pathway analysis showed the influence of N. bombycis infection on many biological processes including folate biosynthesis, spliceosome, nicotinate and nicotinamide metabolism, protein export, protein processing in endoplasmic reticulum, lysosome, biosynthesis of amino acids, ribosome, and RNA degradation. In addition, a number of differentially expressed genes involved in the immune response were identified. Overall, the results of this study provide an understanding of the strategy used by silkworm as a defense against the invasion by N. bombycis. Similar interactions between hosts and pathogens infection may exist in other species. © 2014 Elsevier Inc.

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