Escherichia coli expressing a green fluorescent protein (GFP) in Anopheles stephensi: A preliminary model for paratransgenesis

Issues, like emerging insecticide resistance in
Anopheles mosquitoes, have led to a breakdown in many
vector control programs. In this study, a recombinant
Escherichia coli with plasmid expressing a green fluorescent
protein (E.coli-GFP) was used as a paratransgenesis model to
determine: the possibility of E. coli-GFP trans-stadial transmission.
The effect of the water microflora, of bacteriaimpregnated
sugar solutions, and of blood-feeding on E.
coli-GFP colonization and localization within An. stephensi
tissues, were studied. The results demonstrated the persistence
of E. coli-GFP during molting and metamorphosis events and
its trans-stadial transmission. Also the efficacy of bacteriaimpregnated
sugar solutions for transferring the bacteria to the
adult mosquito’s midgut was shown. A blood meal dramatically
increased the number of bacteria within 24–48 h post
feeding. In addition to fluorescence microscope evaluation,
GFP gene PCR amplification showed the presence of the
bacteria in the midgut of larvae, pupae, and adults up to
13 days after eclosion. Massive colonization of bacteria was
observed in the larvae and in the adult mosquito’s malpighian
tubules which may play a role in retaining bacteria in adult
mosquitos. The results of this study showed that E. coli could
be used as a laboratory model in paratransgenesis studies for
the evaluation of various effector molecules as anti-parasite
agents for malaria and filariasis