Composition of the peritrophic matrix of the tsetse fly, Glossina morsitans morsitans

Abstract

The three-layered peritrophic matrix of Glossina morsitans morsitans is shown, by histochemistry, to be formed of a mixture of glycosaminoglycans, glycoproteins and chitin. In all three layers the glycosaminoglycans contain GlcNAc-hexuronic and Gal-GlcNAc moieties, together with chitin. Glycosaminoglycans in layer 3 are sulphated and sulphated sites have a mean interspace distance of 53 nm - similar to the spacing of fixed charge sites in glomerular basement membrane suggesting a rôle for these sites in the filtration properties of the peritrophic matrix. O-linked oligo- saccharides are present in all three layers. Layer 1 contains the widest variety of glycoprotein oligosaccharide constructs GlcNac and alphalinked GalNAc possibly as GalNAcalpha1,3GalNAc, the latter apparently distal to Galbeta1-4GlcNAc. Lectin binding suggests that layer 2 contains GalNAcalpha1,3Galbeta1,3GlcNAc and that layer 3 contains GalNAc and Galbeta1,4GlcNAc. The evidence for N-linked oligosaccharides is more equivocal. Two dimensional electrophoresis showed that the peritrophic matrix contains a range of proteins, most of which require relatively harsh treatment for their solubilization.

Molecular structure of the peritrophic membrane (PM): Identification of potential PM target sites for insect control

“…A solid NMR analysis showed that proteins accounted for 60% of the PM in Manduca sexta larvae (Kramer et al, 1995). The number of proteins in PMs vary from species to species (Stamm et al, 1978;Adang and Spence, 1982;Dorners and Peters, 1988;Derksen and Granados, 1988;Lehane et al, 1996;Moskalyk et al, 1996). In Type 1 PMs, for example, the number of proteins can be from 2 to about 30 with molecular weights ranging from 14 to over 200 kD by SDS-PAGE analysis (Adang and Spence, 1982;Rupp and Spence, 1985;Derksen and Granados, 1988;Ramos et al, 1994).…”

“…In Type 1 PMs, for example, the number of proteins can be from 2 to about 30 with molecular weights ranging from 14 to over 200 kD by SDS-PAGE analysis (Adang and Spence, 1982;Rupp and Spence, 1985;Derksen and Granados, 1988;Ramos et al, 1994). By two-dimensional SDS-PAGE analysis, more proteins could be detected (Lehane et al, 1996;Moskalyk et al, 1996). In both Type 1 and Type 2 PMs, some proteins are glycosylated (Peters, 1992;Lehane, 1997) or even heavily glycosylated (Wang and Granados, 1997a).…”

Sodalis gen. nov. and Sodalis glossinidius sp. nov., a microaerophilic secondary endosymbiont of the tsetse fly Glossina morsitans morsitans

“…This suggests that strain MIT is devoted to the use of N-acetyl-D-glucosamine and raffinose as primary carbon sources. While polymerized N-acetyl-D-glucosamine (chitin) is known to form the exoskeleton and gut peritrophic membrane of tsetse flies (Lehane et al, 1996;Wigglesworth, 1972), little is known about the presence of raffinose in this insect. In the maize weevil, Sitophilzrs zeamais, an insect known to harbour closely related S-endosymbionts, raffinose is known to be an important dietary component (Baker, 1991).…”

The multilayered innate immune defense of the gut

“…[17] As revealed by electron microscopy, four different layers of chitin fibrils and glycoproteins (e.g. peritrophins) [54,55] are secreted at the beginning of the anterior midgut by the proventriculus [56] and self-assemble to form the PM. [56] Peritrophin genes are also expressed in more distal parts of the midgut, suggesting that this barrier is remodeled along the length of the gut.…”