Cytochemical characterization of microvillar and perimicrovillar membranes in the posterior midgut epithelium of Rhodnius prolixus.
Perimicrovillar membranes (PMM) are structures present on the surface of midgut epithelial cells of the hematophagous insect, Rhodnius prolixus. They cover the microvilli and are especially evident 10 days after blood meal, providing the compartmentalization of the enzymatic processes in the intestinal microenvironment. Using an enzyme cytochemical approach, Mg2+-ATPase and ouabain-sensitive Na+K+-ATPase activities were observed in the plasma (or microvillar) membrane (MM) of midgut cells and in the PMM. In contrast, alkaline phosphatase was only detected in MM. Using cationized ferritin and colloidal iron hydroxide particles, anionic sites were found only on the luminal surface of the PMM. Using fluorescein isothiocyanate (FITC)-labeled lectins, residues of alpha-d-galactose, mannose, N-acetyl-neuraminic acid, N-acetyl-d-galactosamine and N-acetyl-galactosamine-alpha-1,3-galactose were detected on the apical surface of posterior midgut epithelial cells. On the other hand, using FITC-labeled neoglycoproteins (NGP) it was possible to detect the presence of carbohydrate binding molecules (CBM) recognizing N-acetyl-d-galactosamine, alpha-d-mannose, alpha-l-fucose and alpha-d-glucose in the posterior midgut epithelium. The use of digitonin showed the presence of sterols in the MM and PMM. These results have led the authors to suggest that for some components the PMM resembles the MM lining the midgut cells of R. prolixus, composing a system which covers the microvilli and stretches to the luminal space.
Albuquerque-Cunha
José M
JM
Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Avenida Alberto Lamego, 2000, Horto, Campos dos Goytacazes, Rio de Janeiro, CEP 28.015-620, Brazil.
Gonzalez
Marcelo S
MS
Garcia
Elói S
ES
Mello
Cícero B
CB
Azambuja
Patrícia
P
Almeida
João C A
JC
de Souza
Wanderley
W
Nogueira
Nadir F S
NF
D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D016650:Fluorescein-5-isothiocyanate; D006651:Histocytochemistry; D007413:Intestinal Mucosa / Q000166:cytology*; D008871:Microvilli / Q000648:ultrastructure*; D012239:Rhodnius / Q000166:cytology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013261:Sterols / Q000378:metabolism
D013261:Sterols; D017301:Ca(2+) Mg(2+)-ATPase; D000254:Sodium-Potassium-Exchanging ATPase; D016650:Fluorescein-5-isothiocyanate