Haemozoin formation in the midgut of the blood‐sucking insect Rhodnius prolixus

FEBS Letters

Masuda, Hatisaburo¹  Oliveira, Pedro L.¹  de Souza, Wanderley²  Braga, Cláudia M.S.³  Oliveira, Marcus F.¹  Dansa-Petretski, Marı́lvia⁴  Silva, José R.⁴ 

[1] Departamento de Bioquı́mica Médica, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, Centro de Ciências da Saúde, Av. Brigadeiro Trompowsky, s/n, Rio de Janeiro, RJ 21941-590, Brazil;Instituto de Biofı́sica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-590, Brazil;Petrobrás/CENPES, Divisão de Quı́mica, Setor de Quı́mica Orgânica, Cidade Universitária, Rio de Janeiro, RJ 21949-900, Brazil;Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ 28015-620, Brazil

关键词: Hemozoin;    Heme;    Chloroquine;    Rhodnius prolixus;   

DOI  :  10.1016/S0014-5793(00)01786-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Malaria parasites digest haemoglobin and detoxify the free haem by its sequestration into an insoluble dark-brown pigment known as haemozoin (Hz). Until recently, this pigment could be found only in Plasmodium parasites. However, we have shown that Hz is also present in the midgut of the blood-sucking insect Rhodnius prolixus [Oliveira et al. (1999) Nature 400, 517–518]. Here we show that Hz synthesis in the midgut of this insect is promoted by a particulate fraction from intestine lumen. Haem aggregation activity is heat-labile and is inhibited in vitro by chloroquine (CLQ). Inhibition of Hz formation in vivo by feeding insects with CLQ leads to increased levels of haem in the haemolymph of the insect, which resulted in increased lipid peroxidation. Taken together, these results indicate that a factor capable of promoting Hz crystallisation is present in R. prolixus midgut and that this activity represents an important physiological defence of this insect against haem toxicity.

【 授权许可】

Unknown