Perimicrovillar membranes promote hemozoin formation into Rhodnius prolixus midgut

Rhodnius prolixus is a hematophagous insect that ingests large quantities of blood in each blood-feeding session. This ingested blood provides important nutrients to sustain the insect's oogenesis and metabolic pathways. During the digestive process, however, huge amounts of heme are generated as a consequence of the hemoglobin breakdown. Heme is an extremely dangerous molecule, since it can generate reactive oxygen species in the presence of oxygen that impair the normal metabolism of the insect. Part of the hemoglobin-derived heme can associate with the perimicrovillar membranes (PMM) in the gut lumen of R. prolixus; in this study we demonstrate the participation of the PMM in a heme detoxification process. These membranes were able to successfully induce heme aggregation into hemozoin (Hz). Heme aggregation was not dependent on the erythrocyte membranes, since the contribution of these membranes to the process was negligible, demonstrating that the ability to induce heme aggregation is a feature of the PMM, possibly representing a pre-adaptation of the hemipterans to feeding on blood.