title: Protease inhibitors in Bombyx mori silk might participate in protecting the pupating larva from microbial infection.
abstract: Pupae inside cocoons rarely suffer from disease. It is apparent that some factors in the cocoon exert antimicrobial effects whereby the pupae inside can be protected from microbial infection. In the present study, we investigated the expression of cocoon protease inhibitors using immunoblotting and activity staining. Enzymatic hydrolysis of cocoon proteins in vitro was performed to characterize their roles in protecting the cocoon from microbial proteases. We found that some protease inhibitors, particularly trypsin inhibitor-like (TIL)-type protease inhibitors, can be secreted into the cocoon layer during the spinning process, thereby providing effective protection to the cocoon and pupa by inhibiting the extracellular proteases that can be secreted by pathogens.
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China.|Vitamin D Research Institute, Shaanxi University of Technology, Hanzhong, Shaanxi Province, China.
authors.forename: You-Shan
authors.initials: YS
authors.lastname: Li
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China.
authors.forename: Hua-Wei
authors.initials: HW
authors.lastname: Liu
authors.affiliation: School of Management, Shaanxi University of Technology, Hanzhong, Shaanxi Province, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China.
authors.forename: Qing-You
authors.initials: QY
authors.lastname: Xia
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhao
mesh_terms: D000818:Animals; D012831:Bombyx / Q000254:growth & development / Q000378:metabolism* / Q000382:microbiology; D019476:Insect Proteins / Q000378:metabolism*; D007814:Larva / Q000378:metabolism; D011679:Pupa / Q000378:metabolism / Q000382:microbiology; D012333:RNA, Messenger / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000235:genetics / Q000378:metabolism*; D047011:Silk / Q000032:analysis*
chemical_list: D019476:Insect Proteins; D012333:RNA, Messenger; D015842:Serine Proteinase Inhibitors; D047011:Silk
keywords: Bombyx mori; cocoon; enzymatic hydrolysis; microbial proteases; protease inhibitors; pupating larva