The Anopheles gambiae complex consists of at least seven morphologically indistinguishable species of mosquitoes in the genus Anopheles. The complex was recognised in the 1960s and includes the most important vectors of malaria in sub-Saharan Africa, particularly of the most dangerous malaria parasite, Plasmodium falciparum. It is one of the most efficient malaria vectors known. The An. gambiae mosquito additionally transmits Wuchereria bancrofti which causes Lymphatic philariasis, more commonly known as elephantiasis.
A. gambiae sensu lato
Discovery and elementsEdit
- Anopheles arabiensis
- Anopheles bwambae
- Anopheles melas
- Anopheles merus
- Anopheles quadriannulatus
- Anopheles gambiae sensu stricto
- Anopheles coluzzii
- Anopheles amharicus
The individual species of the complex are morphologically difficult to distinguish from each other, although it is possible for larvae and adult females. The species exhibit different behavioural traits. For example, Anopheles quadriannulatus is both a saltwater and mineralwater species. A. melas and A. merus are saltwater species, while the remainder are freshwater species.Anopheles quadriannulatus generally takes its blood meal from animals (zoophilic), whereas Anopheles gambiae sensu stricto generally feeds on humans, i.e. is considered anthropophilic. Identification to the individual species level using the molecular methods of Scott et al. (1993) can have important implications in subsequent control measures.
Anopheles gambiae in the strict senseEdit
An. gambiae s.s. has been discovered to be currently in a state of diverging into two different species—the Mopti (M) and Savannah (S) strains—though as of 2007, the two strains are still considered to be a single species. The An. gambiae s.s. genome has been sequenced three times, once for the M strain, once for the S strain, and once for a hybrid strain. Currently, ~90 miRNA have been predicted in the literature (38 miRNA officially listed in miRBase) for An. gambiae s.s. based upon conserved sequences to miRNA found in Drosophila.
The mechanism of species recognition appears to be sounds emitted by the wings and identified by Johnston's organ.
Fecundity of A. gambiae depends on the detoxification of reactive oxygen species (ROS) by catalase. Reduction in catalase activity significantly reduces reproductive output of female mosquitoes, indicating that catalase plays a central role in protecting oocytes and early embryos from ROS damage.
An. gambiae invaded northeastern Brazil in 1930, which led to a malaria epidemic in 1938/1939. The Brazilian government assisted by the Rockefeller Foundation in a programme spearheaded by Fred Soper eradicated these mosquitoes from this area. This effort was modeled on the earlier success in eradication of Aedes aegypti as part of the yellow fever control program. The exact species involved in this epidemic has been identified as An. arabiensis.
Role in Malaria ResearchEdit
The spread of malaria by the female mosquito, Anopheles gambiae, is dependent, amongst other things, on its ability to fly. This in turn, is dependent on the adipokinetic hormone, Anoga-HrTH (pGlu-Leu-Thr-Phe-Thr-Pro-Ala-Trp-NH2). No crystal structure of this important neuropeptide is available and hence NMR restrained molecular dynamics was used to investigate its conformational space in aqueous solution and when bound to a membrane surface. The results showed that Anoga-HrTH has an almost cyclic conformation that is stabilized by a hydrogen bond between the C-terminus and Thr3. Upon docking of the agonist to its receptor, this H-bond is broken and the molecule adopts a more extended structure.Preliminary AKHR docking calculations give the free energy of binding to be −47.30 kJ/mol. There is a close correspondence between the structure of the docked ligand and literature structure–activity studies.Information about the 3D structure and binding mode of Anoga-HrTH to its receptor is vital for the design of suitable mimetics which can act as insecticides. 
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