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Defense role of the cocoon in the silk worm Bombyx mori L.
Author(s) -
Pandiarajan Jeyaraj,
Cathrin Britto P.,
Pratheep Thangaraj,
Krishnan Muthukalingan
Publication year - 2011
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.5213
Subject(s) - silk , bombyx mori , sericulture , chemistry , antimicrobial , bacillus thuringiensis , gel electrophoresis , microbiology and biotechnology , polyacrylamide gel electrophoresis , antimicrobial peptides , bombyx , bacteria , biology , biochemistry , enzyme , computer science , operating system , genetics , gene
Silk from the domesticated silk worm Bombyx mori procures foreign body response naturally, so it has been utilized as a biomaterial for decades. In India the prime focus of the sericulture industry is to improve silk production with high quality silk. Naturally, the silk worm builds its cocoon not only with silk proteins, but also with antimicrobial proteins to avoid infection since the cocoon is non‐motile and non‐feeding. The aim of the present study is to elucidate the antimicrobial proteins that persist in the cocoon of the silk worm Bombyx mori . At the pupal stage, the silk worm cocoon shell extract was prepared from the day of pupation (P0) to the day of natural rupture of the cocoon for the eclosion of moth (NR). Using the cocoon shell extract a microbial susceptibility test was performed by the disc diffusion method against the microbes Escherchia coli , Bacillus cereus , Staphylococcus aureus , Pseudomonas aeruginosa , and Klebsiella pneumoniae . The development of a zone of inhibition against the microbes confirmed the presence of antimicrobial/immunogenic activity of the cocoon shell extract. For further analysis, the cocoon shell extract was subjected to 7–15% sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS‐PAGE). The protein profile of the cocoon extract revealed the coomassie blue stained bands resolved from the 150 – 15 kDa molecular range. Interestingly, a polypeptide localized at around 29 kDa showed remarkable expressional changes during the development of pupa. To characterize the 29 kDa protein, it was eluted from the gel, digested with trypsin and analyzed by matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS). The trypsin‐digested peptide peaks were analyzed through MASCOT and peptides were matched with the NCBI nr database. The peptides were very well matched with the 18 wheeler protein, which is reported to be responsible for innate immunity, belonging to the Toll family in insects and responsible for cellular mediated immunity. Copyright © 2011 John Wiley & Sons, Ltd.