Major African Malaria Vector Research Articles

Genes identified by an expression screen of the vector mosquito Anopheles gambiae display differential molecular immune response to malaria parasites and bacteria.

We performed a gene expression screen of the entire transcriptome of the major African malaria vector Anopheles gambiae for immune response genes in adult female mosquitoes, which is the developmental stage infected by malaria parasites. Mosquitoes were immune-stimulated for subtractive cloning by treatment with bacterial lipopolysaccharide, a potent and general elicitor of the innate immune response, and by injury. The screen yielded a highly enriched cDNA library in which more than half of the clones were immune responsive. In this paper, we describe 23 immune-regulated genes, including putative protease inhibitors, serine proteases, regulatory molecules, and a number of genes without known relatives. A molecule related to the protease inhibitor alpha-2-macroglobulin responded strongly to malaria parasite infection, but displayed little or no response to bacteria, whereas other genes exhibited the inverse pattern. These results indicate that the insect immune system discriminates between molecular signals specific to infection with bacteria and malaria parasites.

Ribosomal DNA Probes for Identification of Member Species of the Anopheles gambiae Complex

Many insects belong to species complexes wherein member species are morphologically indistinguishable. Yet, in numerous cases, both economic and medical exigencies require that the species of such individuals be reliably determined. The specific problem addressed here concerns the Anopheles gambiae mosquito complex which includes An. gambiae and An. arabiensis, currently the two major African malaria vectors. The present work uses a ribosomal DNA gene probe to differentiate member species of this complex. The method is shown to be extremely useful and sensitive because it can easily test just portions of a single dried adult. The rationale for using ribosomal DNA clones to provide such diagnostic probes to distinguish among other morphologically identical insect species is also discussed.