Intrinsic antimicrobial properties of silk spun by genetically modified silkworm strains.
Alessio Saviane, Ottavia Romoli, Andrea Bozzato, Giuliano Freddi, Chiara Cappelletti, Elena Rosini, Silvia Cappellozza, Gianluca Tettamanti, Federica Sandrelli
Author Information
Alessio Saviane: CREA Department of Agriculture and Environment (CREA-AA), Sericulture Laboratory of Padua, Via Eulero 6a, 35143, Padua, Italy.
Ottavia Romoli: Department of Biology, University of Padova, Via Ugo Bassi 58/B, 35131, Padua, Italy.
Andrea Bozzato: Department of Biology, University of Padova, Via Ugo Bassi 58/B, 35131, Padua, Italy.
Giuliano Freddi: Innovhub-SSI, Silk Area, Via G. Colombo, 83, 20133, Milan, Italy.
Chiara Cappelletti: Innovhub-SSI, Silk Area, Via G. Colombo, 83, 20133, Milan, Italy.
Elena Rosini: Department of Biotechnology and Life Sciences, University of Insubria, Via J.H. Dunant, 3, 21100, Varese, Italy.
Silvia Cappellozza: CREA Department of Agriculture and Environment (CREA-AA), Sericulture Laboratory of Padua, Via Eulero 6a, 35143, Padua, Italy.
Gianluca Tettamanti: Department of Biotechnology and Life Sciences, University of Insubria, Via J.H. Dunant, 3, 21100, Varese, Italy. gianluca.tettamanti@uninsubria.it. ORCID
Federica Sandrelli: Department of Biology, University of Padova, Via Ugo Bassi 58/B, 35131, Padua, Italy. federica.sandrelli@unipd.it. ORCID
The domesticated silkworm, Bombyx mori, is a fundamental insect for silk industry. Silk is obtained from cocoons, protective envelopes produced during pupation and composed of single raw silk filaments secreted by the insect silk glands. Currently, silk is used as a textile fibre and to produce new materials for technical and biomedical applications. To enhance the use of both fabrics and silk-based materials, great efforts to obtain silk with antimicrobial properties have been made. In particular, a convincing approach is represented by the enrichment of the textile fibre with antimicrobial peptides, the main effectors of the innate immunity. To this aim, silkworm-based transgenic techniques appear to be cost-effective strategies to obtain cocoons in which antimicrobial peptides are integrated among the silk proteins. Recently, cocoons transgenic for a recombinant silk protein conjugated to the silkworm Cecropin B antimicrobial peptide were obtained and showed enhanced antibacterial properties (Li et al. in Mol Biol Rep 42:19-25, https://doi.org/10.1007/s11033-014-3735-z , 2015a). In this work we used the piggyBac-mediated germline transformation to generate several transgenic B. mori lines able to overexpress Cecropin B or Moricin antimicrobial peptides at the level of the silk gland. The derived cocoons were characterised by increased antimicrobial properties and the resulting silk fibre was able to inhibit the bacterial growth of the Gram-negative Escherichia coli. Our results suggest that the generation of silkworm overexpressing unconjugated antimicrobial peptides in the silk gland might represent an additional strategy to obtain antimicrobial peptide-enriched silk, for the production of new silk-based materials.
