Cellular localisation of aminopeptidase in the midgut of Rhodnius prolixus St�l (Hemiptera:Reduviidae) during blood digestion

Autor: A. E. R. Downe, Peter F. Billingsley
Rok vydání: 1985
Předmět:
Zdroj: Cell and Tissue Research. 241:421-428
ISSN: 1432-0878
0302-766X
DOI: 10.1007/bf00217189
Popis: By use of the artificial substrate leucyl-β-naphthylamide, aminopeptidase was localised in the midgut cells of the haematophagous insect Rhodnius prolixus before and at various times up to 25 days after a meal of rabbit blood. The enzyme was primarily associated with the membranes of the microvilli, with extracellular membrane layers and with the lysosomes of the midgut cells. Aminopeptidase activity was also detected on the rough endoplasmic reticulum and at the periphery of intracellular storage vesicles. The absence of aminopeptidase on the microvilli of the crop supports the conclusion that the crop is not involved in the digestion of blood-meal proteins and that protein digestion is restricted to the intestine. The sites of localisation are in accordance with models for the spatial separation of digestive enzymes in the midgut of several non-haematophagous insects, and this suggests that aminopeptidase plays a major role in the terminal digestion of the blood meal. The changes in enzyme localisation during the digestive period correlate with previously described cycles of digestive-enzyme activity and changes in midgut ultrastructure. A model for blood protein digestion in R. prolixus is described.
Databáze: OpenAIRE
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