Some unique fungi in soil have adapted structures such as sticky knobs, constricting loops, or hyphal (fungal thread) matrices to trap nematodes, which are small worm-like animals belonging to the phylum Nematoda. These fungi are known as nematophagous or nematode-eating fungi. The morphological structure of the traps differs depending on the species. Some species capture nematodes with adhesive cells using extracellular polymers that collect at the site of attachment between the fungus and the nematode. Another fascinating mechanism is constricting loops, where the fungi has specialized cells that rapidly fill with water and decrease the diameter of the loop in the process. They physically ensnare the nematode.  The nematode will struggle to free itself but usually cannot. These organisms were found on cornmeal agar plates containing wet soil as described by Loynachan (2) and photographed at 100, 500, and 1,000x magnifications. A downloadable, high-resolution version of this movie in RealMedia format is available at http://www.agron.iastate.edu/~loynachan/mov/.

References.

1.  Barron, G. L. 1977. The nematode-destroying fungi. Canadian Biological Publications, Guelph, Ontario, Canada.

2.  Loynachan, T. E. 2006. Quick, easy method to show living soil organisms to high school or beginning-level college students. J. Nat. Resour. Life Sci. Educ. 35:202–208.

3.  Tunlid, A., T. Johansson, and B. Nordbring-Hertz. 1991. Surface polymers of the nematode-trapping fungus Arthrobotrys oligospora. J. Gen. Microbiol. 137:1231–1240. [Online.]  http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=1919501&query_hl=2&itool=pubmed_DocSum.