title: Ricin-B-lectin enhances microsporidia Nosema bombycis infection in BmN cells from silkworm Bombyx mori.
abstract: Nosema bombycis is an obligate intracellular parasitic fungus that utilizes a distinctive mechanism to infect Bombyx mori Spore germination can be used for host cell invasion; however, the detailed mechanism remains to be elucidated. The ricin-B-lectin (RBL) gene is significantly differentially regulated after N. bombycis spore germination, and NbRBL might play roles in spore germination and infection. In this study, the biological function of NbRBL was examined. Protein sequence analysis showed that NbRBL is a secreted protein that attaches to carbohydrates. The relative expression level of the NbRBL gene was low during the first 30 h post-infection (hpi) in BmN cells, and high expression was detected from 42 hpi. Gene cloning, prokaryotic expression, and antibody preparation for NbRBL were performed. NbRBL was detected in total and secreted proteins using western blot analysis. Subcellular localization analysis showed that NbRBL is an intracellular protein. Spore adherence and infection assays showed that NbRBL could enhance spore adhesion to BmN cells; the proliferative activities of BmN cells incubated with anti-NbRBL were higher than those in negative control groups after N. bombycis infection; and the treatment groups showed less damage from spore invasion. We therefore, propose that NbRBL is released during spore germination, enhances spore adhesion to BmN cells, and contributes to spore invasion.
authors.affiliation: Laboratory of Invertebrate Pathology, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Han
authors.initials: H
authors.lastname: Liu
authors.affiliation: Cancer Institute of Integrative Medicine, Tongde Hospital of Zhejiang Province, Hangzhou 310058, China.
authors.forename: Mingqian
authors.initials: M
authors.lastname: Li
authors.affiliation: Laboratory of Invertebrate Pathology, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Shunfeng
authors.initials: S
authors.lastname: Cai
authors.affiliation: Laboratory of Invertebrate Pathology, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Xinyi
authors.initials: X
authors.lastname: He
authors.affiliation: Laboratory of Invertebrate Pathology, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Yongqi
authors.initials: Y
authors.lastname: Shao
authors.affiliation: Laboratory of Invertebrate Pathology, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China xmlu@zju.edu.cn.
authors.forename: Xingmeng
authors.initials: X
authors.lastname: Lu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D012831:Bombyx / Q000469:parasitology*; D002460:Cell Line; D005786:Gene Expression Regulation; D016818:Nosema / Q000472:pathogenicity*; D012276:Ricin / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*
chemical_list: D012276:Ricin
keywords: Nosema bombycis; adhesion; invasion; microsporidia; ricin-B lectin