Parasitology


Programmed cell death and the protozoan parasite

Apoptosis-like death as a feature of malaria infection in mosquitoes


H. HURD a1c1, K. M. GRANT a1 and S. C. ARAMBAGE a1
a1 Centre for Applied Entomology and Parasitology, Institute for Science and Technology in Medicine, University of Keele, Staffordshire, ST5 5BG, UK

Article author query
hurd h   [PubMed][Google Scholar] 
grant km   [PubMed][Google Scholar] 
arambage sc   [PubMed][Google Scholar] 

Abstract

Malaria parasites of the genus Plasmodium make a hazardous journey through their mosquito vectors. The majority die in the process, many as a result of the action of mosquito defence mechanisms. The mosquito too is not unscathed by the encounter with these parasites. Tissue damage occurs as a result of mid-gut invasion and reproductive fitness is lost when many developing ovarian follicles are resorbed. Here we discuss some of the mechanisms that are involved in killing the parasite and in the self-defence mechanisms employed by the mosquito to repair the mid-gut epithelium and to manipulate resources altering the trade-off position that balances reproduction and survival. In all cases, cells die by apoptotic-like mechanisms. In the midgut cells, apoptosis-induction pathways are being elucidated, the molecules involved in apoptosis are being recognised and Drosophila homologues sought. The death of ookinetes in the mosquito mid-gut lumen is associated with caspase-like activity and, although homologues of mammalian caspases are not present in the malaria genome, other cysteine proteases that are potential candidates have been discussed. In the ovary, apoptosis of patches of follicular epithelial cells is followed by resorption of the developing follicle and a subsequent loss of egg production in that follicle.


Key Words: Apoptosis; Plasmodium; malaria; mosquito cysteine proteases.

Correspondence:
c1 Centre for Applied Entomology and Parasitology, Institute for Science and Technology in Medicine, University of Keele, Staffordshire, ST5 5BG, UK. Tel: +44 1782 583034. Fax: +44 1782 583516. Email: h.hurd@keele.ac.uk


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