Effects of chelators (EGTA, EDTA) and calcium ions on nematode capture by the nematode-trapping fungusArthrobotrys ellipsospora

The nematode-trapping fungusArthrobotrys ellipsospora developed an adhesive knob and trapped nematodes when cultured on a low-nutrient medium. It also trapped polystyrene beads in the same way. The adhesive knob produced mucus that was stained with alcian blue, while mycelium of the fungus was stained with periodic acid/Schiff (PAS). The amount of mucus increased with in days after culturing in the low-nutrient media. The fungus completely lost its ability to trap nematodes when treated with EDTA and EGTA, but it recovered the ability after incubation in the presence of a low concentration of Ca (10⁻⁶–10⁻⁷ M) for 1 h. Calmodulin inhibitor W-7 also inhibited the trapping ability of the fungus, and there was a significant (p<0.05) difference between the effects of W-7 and W-5. Ca-binding protein was also detected in the fungus.