Project description:Bombyx mori cocoon has a multi-layer structure that provides optimal protection for silkworm pupa. Research on the mechanical properties of the multi-layer structure revealed structure-property relationships of the cocoon. Here, we investigated the protein components of the B. mori cocoon in terms of its multi-layer structure. Liquid chromatography-tandem mass spectrometry identified 286 proteins from the multiple cocoon layers. In addition to fibroins and sericins, we identified abundant protease inhibitors, seroins and proteins of unknown function. By comparing protein abundance across layers, we found that the outermost layer contained more sericin1 and protease inhibitors and the innermost layer had more seroin1. As many as 36 protease inhibitors were identified in cocoons, indicating efficient inhibitory activities against a fungal protease. Thus, we propose that more abundant protease inhibitors in the outer cocoon layers may provide better protection for the cocoon. This study increases our understanding of the multi-layer mechanism of cocoons, and helps clarify the biological characteristics of cocoons.
Project description:RNA-Seq of Arabidopsis thaliana plants primed by insect eggs from Pieris brassicae and triggered by insect herbivory against untreated controls in two different developmental phases (vegetative vs. reproductive)
Project description:Spinneret, which locates at the end of the silk gland, is an important tissue for silk spinning. Although it has been discovered for hundreds of years, its particular roles in silk spinning and fiber formation are still unclear. Here we report the first proteome profile of silkworm spinnerets by LC-MS/MS. Totally, 1572 non-redundant proteins and 232 differential expressed proteins were identified in the spinneret from the spinning larvae and the third day of fifth instar larvae. Silk fiber formation related proteins, such as cuticle proteins, ion-transporting proteins, muscular proteins, and energy metabolic proteins, were abundant in the spinneret. By analyzing the signal pathways, we discovered that the processes associated with energy metabolism were active in spinneret. GO enrichment analysis revealed that the differential expressed proteins were involved in energy metabolism, chitin binding, and cuticle construction. The active energy metabolism might provide abundant energy for the muscle contraction, ion and water transporting. The chitin binding and cuticle construction process might provide sufficient shear forces for silk formation. This dataset suggests that the spinneret provided a suitable physiological and biochemical environment for silk formation, and will be helpful for elucidating the functions of spinneret.