SALIVARY-GLAND SURFACE CARBOHYDRATE VARIATIONS IN 3 SPECIES OF THE ANOPHELES-GAMBIAE COMPLEX

Fluorescein isothiocyanate (FITC)-conjugated lectins (agglutinins) wer e employed as probes to distinguish between the various carbohydrates present on the surface of salivary glands of three species of mosquito of the Anopheles gambiae complex. Of twenty lectins tested, eight (Co ncanavalin A- Con A, Lathyrus odoratus- LOA, Lens culinaris, Pisum sat ivum-PSA, Vicia faba- VFA, Triticum vulgaris, Maclura pomifera- MPA an d Ulex europaeus) specifically reacted with the salivary gland membran e. Both mannosyl and N-acetylglucosamine moieties were detected in the three Anopheles gambiae sensu stricto strains, the two An. arabiensis strains and a single An. merus strain examined. Variations in the deg rees of fluorescent intensities of Con A and MPA in particular suggest ed interspecies differences in membrane mannosyl and galactosyl residu es on the salivary gland lobes of the three mosquito species in this s tudy. Furthermore, intraspecific variations in mannose as indicated by Con A, LOA, PSA and VFA staining were demonstrated between the An. ga mbiae s.s. strains. The use of either peroxidase-labelled or biotinyla ted lectins confirmed the binding specificities of the above lectins. The consistent differences observed in lectin binding suggest that var iations occur in salivary gland surface carbohydrate residues and that lectins can be used to distinguish between at least some members of t he An. gambiae complex.