Project description:In this study we conducted proteomics analyses of historical and contemporary Bombyx mori cocoon shells to case-study the human-driven introduction and diversification of this species in Europe. We employed LC-MS/MS analyses protocols for 81 cocoon shell samples to identify that the cocoon shell of this species contains on average 98±13 (Mean±SD) proteins, Our proteomic datasets provide a valuable foundation for advancing further exploitations of silkworm cocoon shells in multiple scientific perspectives.
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:The silkworm cocoon coat is a crucial natural barrier during the pupal stage, protecting the insect from patho-gens and environmental stress and containing silk proteins with notable antioxidant and antimicrobial activities. In this study, water-soluble proteins were extracted from the outer cocoon layer of the Bombyx mori N4 strain using phosphate-buffered saline (PBS) and 8 M urea, and the two buffer systems were compared in terms of protein yield, bioactivity, and proteomic composition. Urea-based extraction markedly increased the total protein yield, whereas the PBS extract showed stronger radical-scavenging capacity and more pronounced inhibition of fungal growth. Proteomic analysis further revealed clear differences between the two methods in sericin-to-fibroin ratios, recovery of defense-related proteins, and extraction efficiency for membrane-associated proteins. These results provide a ba-sis for the functional exploitation of cocoon coat proteins and for selecting appropriate extraction strategies ac-cording to different research or application goals.
Project description:This study established, for the first time, a system for extracting water-soluble active proteins from the cocoon layers of multiple pigmented silkworm varieties and systematically evaluated their consistent antioxidant activities together with variety-specific antimicrobial functions. DIA-based proteomics identified 462 catalytic and binding proteins, revealing compositional differences among the three varieties and demonstrating that active protein diversity underlies the observed divergence in antimicrobial efficacy. Differential protein analysis highlighted zonadhesin-like proteins as key components, with TIL domains predicted by AlphaFold 3 to form a unique convex loop-mediated interaction interface. This work provides the first evidence of high-abundance insect-derived zonadhesin-like proteins in the cocoon matrix, and although their functional roles remain uncharacterized, the finding establishes a novel direction for future mechanistic research.
Project description:<p> The decline in insect populations is indisputable. Currently, the effects of persistent organic pollutants on insect populations have not been sufficiently investigated. Maternal transfer of pollutants is considered to be an inherently correct reason for sex differences in pollutant levels in oviparous organisms. Therefore, in this study, we exposed silkworms (Bombyx mori) to different levels of polychlorinated biphenyls (PCBs) to investigate their effects on silkworm development and the sex-specific regulation of PCBs during metamorphosis. PCB exposure causes disorders in amino acid, energy, nucleotide, and vitamin metabolism and induces neurotoxicity, oxidative stress, and inflammation, leading to lower larval weight, success of cocoon breaking, and egg production, and an elevated ratio of ecdysone to juvenile hormone. During the emergence process, PCBs biotransformation differed in a sex-specific manner in silkwormswith a higher degree of biotransformation in females than in males as shown by the compound-specific isotope analysis, which results in lower PCB concentrations in the former. In this case, it is biotransformation rather than maternal transfer that causes the lower PCB levels in females than in males.</p>