The adhesion of conidia of Drechmeria coniospora to the
nematode Panagrellus redivivus was reduced after treatment of
the conidia with Pronase E, or the detergents sodium dodecyl sulphate (SDS)
and dodecyltrimethylammonium bromide (DTAB)
suggesting involvement of proteinaceous compounds in the adhesion process.
In the TEM the thick extracellular pad covering the
adhesive bud of the conidia was completely removed after treatment with
Pronase E. After treatment with SDS or DTAB the
proteinaceous compounds appeared to be dissolved leaving mainly carbohydrates
in the pad as observed on OsO4 without and
OsO4 with Ruthenium red-stained material, respectively. The
detergent extracts after SDS and DTAB treatments contained nine and
seven peptides, respectively, with molecular masses in the range from 6
to 80 kDa on SDS-PAGE gels, and five biotinylated
peptides were found in each extract, after blotting to nitrocellulose membranes,
indicating that these were surface proteins. None of
the detergent extracts was able to reduce adhesion of the conidia after
treatment of the nematodes. The detergent extracts contained
protease- and phosphatase activity. The protease inhibitor, chymostatin,
inhibited infection of nematodes and growth of the conidia,
suggesting the involvement of chymotrypsin-like proteases in the infection
process. On gelatin-containing substrate gel
electrophoresis two proteases were clearly chymostatin sensitive.