Dieme, Constentin, Yssouf, Amina, Vega-Rúa, Anubis, Berenger, Jean-Michel, Failloux, Anna-Bella, Raoult, Didier, Parola, Philippe, Almeras, Lionel, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-IFR48, INSB-INSB-Centre National de la Recherche Scientifique (CNRS), Arbovirus et Insectes Vecteurs - Arboviruses and Insect Vectors, Institut Pasteur [Paris], We thank Pr Ousmane Faye (Université Cheikh Anta Diop (UCAD), Dakar, Senegal) for kindly providing An. coluzzii specimens and Christophe Flaudrops (URMITE-IRD198, Marseille, France) for his advice on the analysis of MALDI-TOF MS profiles. We would like to thank Ricardo Lourenço-de-Oliveira for providing mosquitoes from Manaus in Brazil. This manuscript has been reviewed and corrected by American Journal Experts, Institut des sciences biologiques (INSB-CNRS)-Institut des sciences biologiques (INSB-CNRS)-Centre National de la Recherche Scientifique (CNRS), and Institut Pasteur [Paris] (IP)
Background The identification of mosquito vectors is generally based on morphological criteria, but for aquatic stages, morphological characteristics may be missing, leading to incomplete or incorrect identification. The high cost of molecular biology techniques requires the development of an alternative strategy. In the last decade, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) profiling has proved to be efficient for arthropod identification at the species level. Methods To investigate the usefulness of MALDI-TOF MS for the identification of mosquitoes at aquatic stages, optimizations of sample preparation, diet, body parts and storage conditions were tested. Protein extracts of whole specimens from second larval stage to pupae were selected for the creation of a reference spectra database. The database included a total of 95 laboratory-reared specimens of 6 mosquito species, including Anopheles gambiae (S form), Anopheles coluzzi (M form), Culex pipiens pipiens, Culex pipiens molestus, Aedes aegypti and 2 colonies of Aedes albopictus. Results The present study revealed that whole specimens at aquatic stages produced reproducible and singular spectra according to the mosquito species. Moreover, MS protein profiles appeared weakly affected by the diet provided. Despite the low diversity of some MS profiles, notably for cryptic species, clustering analyses correctly classified all specimens tested at the species level followed by the clustering of early vs. late aquatic developmental stages. Discriminant mass peaks were recorded for the 6 mosquito species analyzed at larval stage 3 and the pupal stage. Querying against the reference spectra database of 149 new specimens at different aquatic stages from the 6 mosquito species revealed that 147 specimens were correctly identified at the species level and that early and late developmental stages were also distinguished. Conclusions The present work highlights that MALDI-TOF MS profiling may be useful for the rapid and reliable identification of mosquito species at aquatic stages. With this proteomic tool, it becomes now conceivable to survey mosquito breeding sites prior to the mosquitoes’ emergence and to adapt anti-vectorial measures according to the mosquito fauna detected. Electronic supplementary material The online version of this article (doi:10.1186/s13071-014-0544-0) contains supplementary material, which is available to authorized users.