Wound debridement potential of glycosidases of the wound-healing maggot, Lucilia sericata

The wound-healing maggot, Lucilia sericata Meigen (Diptera: Calliphoridae), degrades extracellular matrix components by releasing enzymes. The purpose of this study was to investigate the glycosylation profiles of wound slough/eschar from chronic venous leg ulcers and the complementary presence of glycosidase activities in first-instar excretions/secretions (ES1) and to define their specificities. The predominant carbohydrate moieties present in wound slough/eschar were determined by probing one-dimensional Western blots with conjugated lectins of known specificities. The presence of specific glycosidase activities in ES1 was determined using chromogenic and fluorogenic substrates. The removal of carbohydrate moieties from slough/eschar proteins by glycosidases in ES1 was determined by two-dimensional electrophoresis and Emerald 300 glycoprotein staining. α-d-glucosyl, α-d-mannosyl and N-acetlyglucosamine residues were detected on slough/eschar-derived proteins. Furthermore, it was demonstrated that the treatment of slough/eschar with ES1 significantly reduced uptake of the carbohydrate-specific stain. Subsequently, α-d-glucosidase, α-d-mannosidase and N-acetylglucosaminidase activities were identified in ES1. Specific chromogenic and fluorogenic substrates and gel filtration chromatography showed that these activities result from distinct enzymes. These activities were mirrored in the removal of α-d-glucosyl, α-d-mannosyl and N-acetylglucosamine residues from proteins of slough/eschar from maggot-treated wounds. These data suggest that maggot glycosidases remove sugars from slough/eschar proteins. This may contribute to debridement, which is ultimately accomplished by a suite of biochemically distinct enzymes present in ES1.