Epidermal secretions of terrestrial flatworms and slugs: Lehmannia valentiana mucus contains matrilin-like proteins.
We describe the epidermal mucus of two types of terrestrial invertebrates: free-living flatworms (Tricladida: Terricola), and the slug Lehmannia valentiana (Gastropoda: Pulmonata). Both exhibited similar dry shear strengths (1.4-1.7 MPa). In denaturing gel electrophoresis, the protein fraction of flatworm mucus migrated mainly as a broad band (200-300 kDa). Slug mucus had a higher protein content than flatworm mucus but it contained more carbohydrate than protein, mainly as large heparan sulfate-like glycosaminoglycans. Proteins and glycosaminoglycans were both essential for the mechanical integrity of the slug hydrogel. The protein fraction of slug mucus contained approximately 12 larger proteins (30-300 kDa) and approximately 6 smaller ones (10-28 kDa). Complete cDNA clones were obtained for the slug mucus 40 kDa protein (Sm40; Genbank accession EF634345) and 85 kDa protein (Sm85; Genbank accession EF634346). Both proteins contain EGF-like repeats and von Willebrand A-domains, and therefore resemble vertebrate matrilins. Many of the larger slug mucus proteins appear to contain A-domains, and these may play a role in the unusual rheological properties of gastropod mucus.
Li
Dongmei
D
CSIRO Molecular and Health Technologies, Sydney Laboratory, North Ryde, NSW, Australia.
Graham
Lloyd D
LD
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary; D004591:Electrophoresis, Polyacrylamide Gel; D004817:Epidermis / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009093:Mucus / Q000378:metabolism*; D010986:Platyhelminths / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D018076:DNA, Complementary; D011506:Proteins