Chemical, biological and structural aspects involved in the attractiveness of hosts to sand flies

Abstract

The olfactory response in insects is initiated by the reception of chemical compounds by the antennas that will be transported to the neurons by means of odor proteins, also known as Odorant Binding Proteins (OBPs), triggering behaviors of approach or repellency of the insect. The studies in chemical ecology investigate the aspects involved in this process such as: identity of the chemical compounds, the molecular interaction and the triggered behaviors. For sand flies, vectors of the etiological agents of several diseases, the area of chemical ecology is under developed when compared to studies with insects of agricultural pests or with other groups of hematophagous insects, such as culicidae. The present project will be divided into two parts and has as a proposal to increase knowledge in the chemical ecology of phlebotomines sand flies in three main aspects: evaluation of the behavioral response of sandflies to hosts infected or not with Leishmania spp; identification of the volatile compounds produced by these two groups of hosts; expression, purification and biophysical characterization of OBPs. For the part of the behavioral tests and identification of volatile compounds, hamsters infected with Leishmania braziliensis and one of its vector species, Nyssomyia neivai will be used. The molecular part will be focused on the vector species of visceral leishmaniasis Lutzomyia longipalpis. We will continue a previous study which identified sequences of OBPs from Lu. longipapis but did not express them. It is expected to express and characterize these proteins in order to eventually find possible protein-ligands that may trigger behavioral responses of attraction or repellency of these insects. (AU)