Heterosis Increases Fertility, Fecundity and Survival of Laboratory-Produced F1 Hybrid Males of the Malaria Mosquito Anopheles coluzzii

The success of vector control strategies aiming to decrease disease transmission via the release of sterile or genetically-modified male mosquitoes critically depends on mating between laboratory-reared males and wild females. Unfortunately, mosquito colonization, laboratory rearing, and genetic manipulations can all negatively affect male competitiveness. Heterosis is commonly used to produce domestic animals with enhanced vigor and homogenous genetic background and could therefore potentially improve the mating performance of mass-reared male mosquitoes. Here, we produced enhanced hybrid males of the malaria mosquito Anopheles coluzzii by crossing two strains colonized 35+ and 8 years ago. We compared the amount of sperm and mating plug proteins they transferred to females, as well as their insemination rate, reproductive success and longevity under various experimental conditions. Across experiments widespread adaptations to laboratory mating were detected in the older strain. In large-group mating experiments, no overall hybrid advantage in insemination rates and the amount of sperm and accessory gland proteins transferred to females was detected. Despite higher sperm activity, hybrid males did not appear more fecund. However, individual-male mating and laboratory-swarm experiments revealed that hybrid males, while inseminating fewer females than older inbred males, were significantly more fertile, producing larger mating plugs and drastically increasing female fecundity. Heterotic males also showed increased longevity. These results validate the use of heterosis for creating hybrid males with improved fitness from long-established inbred laboratory strains. Therefore, this simple approach could facilitate disease control strategies based on male mosquito releases with important ultimate benefits to human health

Target-site resistance mutations (kdr and RDL), but not metabolic resistance, negatively impact male mating competiveness in the malaria vector Anopheles gambiae

The implementation of successful insecticide resistance management strategies for malaria control is currently hampered by poor understanding of the fitness cost of resistance on mosquito populations, including their mating competiveness. To fill this knowledge gap, coupled and uncoupled Anopheles gambiae s.l. males (all M form (Anopheles coluzzii)) were collected from mating swarms in Burkina Faso. This multiple insecticide resistant population exhibited high 1014F kdrR allele frequencies (460%) and RDLR (480%) in contrast to the Ace-1R allele (o6%). Kdr heterozygote males were more likely to mate than homozygote resistant (OR=2.36; Po0.001), suggesting a negative impact of kdr on An. coluzzii mating ability. Interestingly, heterozygote males were also more competitive than homozygote susceptible (OR=3.26; P=0.006), suggesting a heterozygote advantage effect. Similarly, heterozygote RDLR/RDLS were also more likely to mate than homozygote-resistant males (OR=2.58; P=0.007). Furthermore, an additive mating disadvantage was detected in male homozygotes for both kdr/RDL-resistant alleles. In contrast, no fitness difference was observed for the Ace-1 mutation. Comparative microarray-based genome-wide transcription analysis revealed that metabolic resistance did not significantly alter the mating competitiveness of male An. coluzzii mosquitoes. Indeed, no significant difference of expression levels was observed for the main metabolic resistance genes, suggesting that metabolic resistance has a limited impact on male mating competiveness. In addition, specific gene classes/GO terms associated with mating process were detected including sensory perception and peroxidase activity. The detrimental impact of insecticide resistance on mating competiveness observed here suggests that resistance management strategies such as insecticide rotation could help reverse the resistance, if implemented early

Negative Cross Resistance Mediated by Co-treated bed nets: A Potential Means of Restoring Pyrethroid-susceptibility to Malaria Vectors.

Insecticide-treated nets and indoor residual spray programs for malaria control are entirely dependent on pyrethroid insecticides. The ubiquitous exposure of Anopheles mosquitoes to this chemistry has selected for resistance in a number of populations. This threatens the sustainability of our most effective interventions but no operationally practicable way of resolving the problem currently exists. One innovative solution involves the co-application of a powerful chemosterilant (pyriproxyfen or PPF) to bed nets that are usually treated only with pyrethroids. Resistant mosquitoes that are unaffected by the pyrethroid component of a PPF/pyrethroid co-treatment remain vulnerable to PPF. There is a differential impact of PPF on pyrethroid-resistant and susceptible mosquitoes that is modulated by the mosquito's behavioural response at co-treated surfaces. This imposes a specific fitness cost on pyrethroid-resistant phenotypes and can reverse selection. The concept is demonstrated using a mathematical model

Enquete Sur L’etat de Sante et des Conditions de Travail des Riziculteurs des Bas-fonds de la Region de Gagnoa en Côte D’Ivoire

Dans le souci d’atteindre l’autosuffisance alimentaire, les gouvernements ivoiriens successifs ont réalisé de nombreuses retenues d’eau à usage agricole dont les rizières irriguées. Ces retenues d’eau constituent des gîtes de reproduction des vecteurs de maladies. Malheureusement, la préservation de la santé des paysans est parfois négligée dans les projets de développement agricole et les paysans souffrent en silence. Aussi, est-il judicieux d’identifier les maux les plus fréquents en milieu paysan afin de les prévenir ou y apporter des remèdes. A cet effet, une enquête transversale a été menée sur la santé et les conditions de travail des riziculteurs d’une coopérative rizicole (CODERIZ) de Gagnoa regroupant 932 riziculteurs qui exploitent 818 ha. Elle a comporté la visite aux paysans dans leurs rizières, une enquête sur leur connaissance des causes du paludisme, les maladies dont ils souffrent, leurs conditions de travail et une éducation sanitaire auprès de 200 riziculteurs. Cette étude a montré que les riziculteurs manquent de logistiques agricoles (motoculteurs, batteuses, pulvérisateurs etc), d’intrants agricoles (engrais, pesticides), de tenues de protection (bottes, tenues d’épandage des pesticides, etc). Ils sont contraints de travailler torse nu, et par ignorance, ils utilisent leurs mains pour homogénéiser les solutions pesticides et réutilisent les boîtes usagées de produits phytosanitaires. En outre, ces paysans, ont évoqué dans leur milieu 24 maladies dont la plus fréquente est le paludisme. La majorité (95 %) des riziculteurs ignore la cause de cette maladie. Il a été entrepris à leur intention, une éducation sanitaire sur l’utilisation sans risque des pesticides et sur le paludisme. Il est impérieux d’associer aux projets de développements hydro-agricoles des mesures de protection de la santé des paysans.Mots-clefs : Riziculture, santé, conditions de travail, maladies, paludisme, Côte d’Ivoire

O TAMASHEQ NA CONVERGÊNCIA COM O FRANCÊS NO TERRITÓRIO AFRICANO: CASO DO POVO TUAREGUE NO DESERTO DO SAARA, NORTE DO MALI

Esta investigação centra-se no Tamasheq na convergência com o Francês no território africano (Mali). A escolha do tema justifica-se porque a área de substrato Tamasheq / Francês fundamentado na Pedagogia Convergente permanece pouco explorada. O objetivo geral é o de registrar e analisar dados sobre o funcionamento do bilinguismo na aprendizagem de alunos cuja língua nacional é o Tamasheq no contexto escolar de aulas ministradas em Francês. A investigação constituiu–se de: busca de literatura referente à Pedagogia Convergente. A reflexão, à luz da fundamentação teórica reiterou a contribuição da Pedagogia Convergente para a qualidade da aprendizagem escolar de estudantes tamasheq e a relevância do ambiente de estudo marcado pelo ensino bilíngue Tamasheque e Francês.

Molecular dynamic simulation reveals structure differences in APOL1 variants and implication on pathogenesis of chronic kidney disease

Background: According to observational studies, two polymorphisms in the apolipoprotein L1 (APOL1) gene have been linked to an increased risk of chronic kidney disease (CKD) in Africans. One polymorphism involves the substitution of two amino-acid residues (S342G and I384M; known as G1), while the other involves the deletion of two amino-acid residues in a row (N388 and Y389; termed G2). Despite the strong link between APOL1 polymorphisms and kidney disease, the molecular mechanisms via which these APOL1 mutations influence the onset and progression of CKD remain unknown. Methods: To predict the active site and allosteric site on the APOL1 protein, we used the Computed Atlas of Surface Topography of Proteins (CASTp) and the Protein Allosteric Sites Server (PASSer). Using an extended molecular dynamics simulation, we investigated the characteristic structural perturbations in the 3D structures of APOL1 variants. Results: According to CASTp’s active site characterization, the topmost predicted site had a surface area of 964.892 Å2 and a pocket volume of 900.792 Å3. For the top three allosteric pockets, the allostery probability was 52.44%, 46.30%, and 38.50%, respectively. The systems reached equilibrium in about 125 ns. From 0–100 ns, there was also significant structural instability. When compared to G1 and G2, the wildtype protein (G0) had overall high stability throughout the simulation. The root-mean-square fluctuation (RMSF) of wildtype and variant protein backbone Cα fluctuations revealed that the Cα of the variants had a large structural fluctuation when compared to the wildtype. Conclusion: Using a combination of different computational techniques, we identified binding sites within the APOL1 protein that could be an attractive site for potential inhibitors of APOL1. Furthermore, the G1 and G2 mutations reduced the structural stability of APOL1

Quantitative trait loci for head-bug resistance in sorghum

QTLs were mapped in F2 progeny derived from a cross between the head-bug resistant sorghum cultivar Malisor 84-7 and susceptible S 34. The phenotypic evaluation was conducted in Mali. The mapped population consisted of 217 F2 plants, with 345 homologous and heterologous RFLP probes and 49 microsatellite markers tested. Eighty-one RFLP markers revealed polymorphism between the two parents, and 14 microsatellite markers gave usable amplification products. A genetic map including 92 loci distributed over 13 linkage groups, and covering a total distance of 1160 cM was built. Three significant and seven putative QTLs were detected and placed on the ma

Quantitative trait loci for head-bug resistance in sorghum

QTLs were mapped in F2 progeny derived from a cross between the head-bug resistant sorghum cultivar Malisor 84-7 and susceptible S 34. The phenotypic evaluation was conducted in Mali. The mapped population consisted of 217 F2 plants, with 345 homologous and heterologous RFLP probes and 49 microsatellite markers tested. Eighty-one RFLP markers revealed polymorphism between the two parents, and 14 microsatellite markers gave usable amplification products. A genetic map including 92 loci distributed over 13 linkage groups, and covering a total distance of 1160 cM was built. Three significant and seven putative QTLs were detected and placed on the ma