A zymogel enhances the self-cleaning abilities of the skin of the pilot whale (Globicephala melas)

Enzyme activity in the stratum corneum of the pilot whale Globicephala mela s was investigated employing colorimetric enzyme screening assays combined with NATIVE PAGE, size exclusion chromatography (SEC) and histochemical sta ining procedures. Applying different substrates, several enzymes were detec ted. The histochemical demonstration of some selected hydrolytic enzymes en riched in the stratum corneum showed high extracellular accumulation. As de monstrated by size exclusion chromatography, high molar mass aggregates wer e built up from a glycoprotein-rich 20-30-kD fraction. Using NATIVE PAGE ex periments under non-reducing conditions, a selection of five degrading enzy mes was recovered within the above-reported aggregates. Activity of extrace llular aggregate-attached enzymes in the superficial layer of the stratum c orneum exhibited no remarkable decrease potentially resulting from self-deg radation. We thus conclude that due to their enclosure within the microenvi ronment of aggregates, a zymogel is formed and autolysis of the stratum cor neum is reduced. With respect to the skin surface, the zymogel with hydroly tic activities covering major parts of it enhances the self-cleaning abilit ies of the skin of the pilot whale based on physical pre-requisites by hydr olyzing adhesive glycoconjugates of settling biofouling organisms considere d as primary steps in fouling. (C) 2001 Elsevier Science Inc. All rights re served.