biostudies-literatureUnknown17(9)Matsumoto YCutibacterium acnes is a pathogenic bacterium that cause inflammatory diseases of the skin and intervertebral discs. The immune activation induced by C. acnes requires multiple cellular responses in the host. Silkworm, an invertebrate, generates melanin by phenoloxidase upon recognizing bacterial or fungal components. Therefore, the melanization reaction can be used as an indicator of innate immune activation. A silkworm infection model was developed for evaluating the virulence of C. acnes, but a system for evaluating the induction of innate immunity by C. acnes using melanization as an indicator has not yet been established. Here we demonstrated that C. acnes rapidly causes melanization of the silkworm hemolymph. On the other hand, Staphylococcus aureus, a gram-positive bacterium identicPloS onee0271420https://www.ebi.ac.uk/biostudies/studies/S-EPMC9512201biostudies-literatureAcute melanization of silkworm hemolymph by peptidoglycans of the human commensal bacterium Cutibacterium acnes.PMC9512201Sato EMatsumoto YSugita TfalseAcute melanization of silkworm hemolymph by peptidoglycans of the human commensal bacterium Cutibacterium acnes.Cutibacterium acnes is a pathogenic bacterium that cause inflammatory diseases of the skin and intervertebral discs. The immune activation induced by C. acnes requires multiple cellular responses in the host. Silkworm, an invertebrate, generates melanin by phenoloxidase upon recognizing bacterial or fungal components. Therefore, the melanization reaction can be used as an indicator of innate immune activation. A silkworm infection model was developed for evaluating the virulence of C. acnes, but a system for evaluating the induction of innate immunity by C. acnes using melanization as an indicator has not yet been established. Here we demonstrated that C. acnes rapidly causes melanization of the silkworm hemolymph. On the other hand, Staphylococcus aureus, a gram-positive bacterium identic2022-01-01T00:00:00Z20222025-04-19T21:50:59.682Z2025-04-19T21:50:59.682ZS-EPMC95122013615548510.1371/journal.pone.0271420