Deltamethrin Resistance Mechanisms in Aedes aegypti Populations from Three French Overseas Territories Worldwide

BACKGROUND:Aedes aegypti is a cosmopolite mosquito, vector of arboviruses. The worldwide studies of its insecticide resistance have demonstrated a strong loss of susceptibility to pyrethroids, the major class of insecticide used for vector control. French overseas territories such as French Guiana (South America), Guadeloupe islands (Lesser Antilles) as well as New Caledonia (Pacific Ocean), have encountered such resistance. METHODOLOGY/PRINCIPAL FINDINGS:We initiated a research program on the pyrethroid resistance in French Guiana, Guadeloupe and New Caledonia. Aedes aegypti populations were tested for their deltamethrin resistance level then screened by an improved microarray developed to specifically study metabolic resistance mechanisms. Cytochrome P450 genes were implicated in conferring resistance. CYP6BB2, CYP6M11, CYP6N12, CYP9J9, CYP9J10 and CCE3 genes were upregulated in the resistant populations and were common to other populations at a regional scale. The implication of these genes in resistance phenomenon is therefore strongly suggested. Other genes from detoxification pathways were also differentially regulated. Screening for target site mutations on the voltage-gated sodium channel gene demonstrated the presence of I1016 and C1534. CONCLUSION /SIGNIFICANCE:This study highlighted the presence of a common set of differentially up-regulated detoxifying genes, mainly cytochrome P450 genes in all three populations. GUA and GUY populations shared a higher number of those genes compared to CAL. Two kdr mutations well known to be associated to pyrethroid resistance were also detected in those two populations but not in CAL. Different selective pressures and genetic backgrounds can explain such differences. These results are also compared with those obtained from other parts of the world and are discussed in the context of integrative research on vector competence

Optimization of the wheat puroindoline-a production in Pichia pastoris

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Influence of nutrient, pH and dissolved oxygen on the production of Metarhizium flavoviride Mf189 blastospores in submerged batch culture

Corresponding author. fax: +33-3-8069-3229.E-mail address: [email protected] (A. Durand).International audienceThe influence of different parameters on the sporulation of Metarhizium flavoviride was studied during submerged cultures in shake flasks and in 5 l bioreactors. The screening in shake flasks of several carbon and nitrogen sources allowed the definition of an optimal medium, based on sucrose and brewer’s yeast with a C/N ratio of 1.6. With this medium, a production of 5.4 _ 108 blastospores per ml (Bspores ml_1) was obtained after 169 h of cultivation. The influence of pH and pO2 was independently studied in 5 l working volume bioreactors using the optimal medium. The best production was obtained with pH and pO2 regulated respectively to 7 and 100%. Finally, when the culture was grown under optimized conditions, the blastospores concentration increased 16-fold, with 1.1 109 Bspores ml-1 obtained after 144 h cultivation. This represents a gain of productivity of about 4.8 time

Single step purification of a wheat 9kDa lipid transfer protein secreted by Pichia pastoris

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Growth Arrest and Terminal Differentiation of Leukemic Myelomonocytic Cells Induced through Ligation of Surface CD23 Antigen.

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