Binding Characteristics of Lectins Involved in the Trapping of Nematodes by Fungi

Abstract

Seventeen saccharides were tested for their ability to bind to the trap lectins of three species of nematode-trapping fungi and prevent nematode capture. The lectin of Arthrobotrys conoides was found to be inhibited by α- d -glucose/ d -mannose and similar saccharides. The lectins of Monacrosporium eudermatum and Monacrosporium rutgeriensis were inhibited by α- l -fucose and 2-deoxy- d -glucose, respectively. Human group O(H) erythrocytes agglutinated to traps of M. eudermatum but not A. conoides or M. rutgeriensis. There was no agglutination of group A or B to traps formed by all three fungi. Exposure of the traps to trypsin eliminated the ability to capture nematodes. The presence of d -glucose/ d -mannose and l -fucose residues on the nematode cuticle was suggested through the use of commercially prepared lectin-peroxidase conjugates.

Role of N -Acetylgalactosamine-Specific Protein in Trapping of Nematodes by Arthrobotrys oligospora

“…The results reported here complement those of others (5,7), who observed that nematode capture is inhibited by various sugars and suggested that entrapment is mediated by interaction of a lectin on the surface of the fungus trap and a specific sugar on the nematode cuticle. The presence of GalNAc residues on the nematode cuticle has already been demonstrated (5, 9).…”

“…However, all evidence for the existence of fungal protein that binds sugar is indirect. It consists solely of demonstrations that exposure of hyphal traps to specific sugars interferes with nematode capture (5,7). It was desirable, therefore, to attempt direct isolation from the fungus of a protein able to bind specific cuticular sugar molecules and influence the process of nematode capture.…”

Genome Studies on Nematophagous and Entomogenous Fungi in China

“…The traps of A. oligospora that are challenged by GalNAc ( N -acetylgalactosamine) lost the ability to capture nematodes [ 35 ]. Other monosaccharaides such as glucose and mannose can also inhibit the capacity of the trapping-fungi to recognize nematodes [ 36 ]. However, the knocked out lectin-coding gene in A. oligospora did not affect the trapping ability or vegetative growth [ 37 ].…”

Carbohydrate/lectin interactions between the nematophagous fungus,Arthrobotrys oligospora, and the infective juveniles ofTrichostrongylus colubriformis(Nematoda)

“…2-Deoxy-D-glucose does not occur in nature and its presence has not been demonstrated on nematode cuticles (Jansson, 1987). This carbohydrate has been shown to inhibit cell wall synthesis in the yeast Saccharomyces cerevisiae (Biely et al 1971) as well as inhibiting nematode capture by A. oligospora, Monacrosporium rutgeriensis (Rosenzweig & Ackroyd, 1983) and Dactylaria Candida (Nordbring-Hertz, Friman & Mattiasson, 1982). The inhibitory effect may therefore be due to interference with the production of a penetration hypha rather than the inhibition of a recognition system.…”