Fluorescein conjugated lectins identify different carbohydrate residues on Glossina peritrophic membranes

Fluorescein-lectin conjugates were used as markers to determine the presence of surface carbohydrates on the peritrophic membranes of 6 Glossina species. Inter- and intra-specific variation in exposed carbohydrate residues was observed. Peritrophic membranes from non-teneral flies appeared to have less exposed surface carbohydrates than those of tenerals. Teneral G. m. morsitans susceptible to trypanosome infection had exposed carbohydrate residues recognised by APA lectin, but these residues were absent in a line of this species refractory to trypanosome infection. It is suggested that at least some of the surface carbohydrates of the peritrophic membrane bind endogenous gut lectin and parasite-surface carbohydrates may influence trypanosome development in Glossina spp.