March 21, 2007
'Glow In The Dark Mosquitoes' Fight MalariaTopics: Medicine
A study published in this week's early online edition of the journal Proceedings of the National Academy of Sciences suggests that transgenic (genetically modified) malaria-resistant mosquitoes have a fitness advantage when feeding on Plasmodium-infected blood, and if released in the wild, could outbreed natural mosquitoes and reduce the spread of malaria. (The genetically engineered mosquitoes with eyes that glow in the dark and do not carry malaria):
Malaria is an infectious disease caused by a single-celled protozoan parasite called Plasmodium of which there are ten species that infect humans. The parasite needs two hosts to complete its life-cycle: female Anopholes mosquitoes, and the bloodstream of a vertebrate where it invades and damages red blood cells.More here ...
Female mosquitoes feed on blood to get the extra protein they need during their egg-laying phase, and thereby transmit Plasmodium from infected vertebrates to non-infected vertebrates.
Dr Marrelli and colleagues had already shown in previous experiments that transgenic anopheline mosquitoes would not pick up the Plasmodium (in this case, they used the species P. berghei) when fed on infected mice.
However, this was the first study where they were able to show that the transgenic mosquitoes had a twofold survival advantage over their nontransgenic siblings. They were more fertile and also enjoyed lower mortality. Again, they demonstrated this using mice as the vertebrate host.
In fact the transgenic mosquitoes eventually replaced non-transgenic ones when fed on infected mice, but when fed on non-infected mice the two mosquito populations remained the same.
In order to identify the transgenic mosquitoes, the researchers inserted an extra gene that made their eyes glow a different colour.
The transgenic mosquitoes were made by activating the SM1 peptide gene in the lumen of their midgut, where the Plasmodium parasite lives during its mosquito -host phase.
Posted by Abdul at March 21, 2007 10:10 AM
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