wpe41F.jpg (27819 bytes) 

Nematode captured by adhesive net has been colonized by the assimilative feeding hyphae of the fungus.  Complete digestion will take place in 12 hours or less.

There is a lectin present in the wall of the net that binds chemically with a carbohydrate (n-acetyl-d-galactosamine) present in the epidermis of the nematode.  This is a chemical bond and cannot be broken - a kind of biological crazy glue - only better.  This molecular  system is referred to as Lectin/Carbohydrate bonding.  Once bonding takes place, the fungus penetrates into the host body, secretes a toxin to inactivate  the nematode, then produces an extensive growth of fungal filaments (hyphae) to explore the body cavity and digest its contents.  It takes about 12 hours to assimilate the nematode.  The materials gleaned from the victim are translocated out of the body to the external hyphal system for further growth of hyphae and production of more trapping devices (adhesive nets).

wpe687.jpg (13662 bytes)

It was shown experimentally (Nordbring-Hertz and Mattiasson, 1979. Nature, 281: 477 )  that a lectin in the trapping device of Arthrobotrys formed a chemical bond with a specific sugar in the wall of the nematode. This bond is impossible to break. Although some nematodes, close to moulting, can rupture their epidermis and escape.

To demonstrate this bonding phenomenon, nets were induced in a number of cultures of Arthrobotrys. The nets were then washed individually with solutions of known sugars. The sugar that saturated the available sites on the adhesive nets of Arthrobotrys was found to be n-acetyl-D-galactosamine and nematodes were not trapped in the cultures to which this sugar was added. It was confirmed that this sugar was a component of the nematode's cuticle.