IONIC ENVIRONMENT AND THE PERMEABILITY PROPERTIES OF THE PERITROPHIC MEMBRANE OF GLOSSINA-MORSITANS-MORSITANS
Authors: Miller, N., Lehane, MJ.,
Year of publication:1993
Journal: Journal of Insect Physiology, , Volume: 39(2), Pages: 139-144.
Publisher: Pergamon-elsevier Science Ltd
Electron microscopy shows that the peritrophic membrane of Glossina morsitans morsitans is trilaminate and suggests that the outer two layers contain negatively charged glycosaminoglycans. There are structural similarities between the vertebrate renal glomerular basement membrane and the tsetse peritrophic membrane. In vitro perfusion experiments show that the presence of calcium ions significantly increases the permeability of the peritrophic membrane to alkaline phosphatase. This effect appears to be saturated in 0.05 M solutions of calcium chloride. The presence of potassium ions at 0.05 M or reduction of the pH to 5.8 does not significantly alter permeability. The permeability of male peritrophic membranes is significantly higher than that of female membranes in some media which suggests a sexual dimorphism in peritrophic membrane composition. In the light of the electron microscopical results it is postulated that calcium ions exert their effect by neutralizing anionic charges in the membrane.