Project Description

Diseases transmitted by insect vectors, such as malaria, dengue fever, yellow fever and leishmaniasis, affect millions of people and caused about 600.000 deaths around the world in 2012, especially in tropical regions(1). In Brazil, population is affected significantly by those diseases. Considering this problem, our project consisted in developing an alternative repellent of that currently sold in the market, more or equally effective in preventing mosquitoes bites that transmits diseases. The main compound in current repellents is DEET (N, N-diethyl-m-toluamide), a toxic molecule which at certain concentrations could be lethal, and therefore must have strict control on its use (9). The main characteristic of our repellent is a longer duration when compared to other products and the replacement of DEET by D-limonene, a less toxic compound. Our proposal was building a bacteria carrying out the production of D-limonene via limonene synthase. To enable long term storage at room temperatures, the bacterial cells that make up the repellent would be plasmolyzed, with suspended metabolism, in a dormant state. The maintenance of this state would be obtained by a solution of polyethylene glycol (PEG) that will raise the osmotic pressure. Once in contact with the skin, PEG solution would be diluted by sweat and inducing osmotic shock in bacteria cells. Then the universal stress protein promoter (UspA) would be activated, inducing expression of limonene synthase. In addition to PEG, other compounds such as glycerol and metal ions in low concentrations would constitute our insect repellent cream, in order to keep bacteria at the required metabolic condition and posterior enzyme activities. This way, the distribution of our repellent may become feasible, allowing its use.