Genome-wide association studies reveal novel loci associated with pyrethroid and organophosphate resistance in Anopheles gambiae

Resistance to insecticides in Anopheles mosquitoes threatens the effectiveness of malaria control, but the genetics of resistance are only partially understood. We performed a large scale multi-country genome-wide association study of resistance to two widely used insecticides: deltamethrin and pirimiphos-methyl, using sequencing data from An. gambiae and An. coluzzii from ten locations in West Africa. Resistance was highly multi-genic, multiallelic and variable between populations. While the strongest and most consistent association with deltamethrin resistance came from Cyp6aa1, this was based on several independent copy number variants (CNVs) in An. coluzzii, and on a non-CNV haplotype in An. gambiae. For pirimiphos-methyl, signals included Ace1, cytochrome P450s, glutathione S-transferases and the nAChR target site of neonicotinoid insecticides. The regions around Cyp9k1 and the Tep family of immune genes showed evidence of cross-resistance to both insecticides. These locally-varying, multi-allelic patterns highlight the challenges involved in genomic monitoring of resistance, and form the basis for improved surveillance methods

Essai de conservation des graines de niebe avec les huiles essentielles extraiteds de Cymbopogon schoenanthus L. Spreng. (Poaceae) et de Ocimum basilicum L. (Lamiaceae)

No Abstract. J. Rech. Sci. Univ. Lomé (Togo) Vol. 7(1) (Serie A) 2005: pp. 93-10

Influência do período de armazenamento do caupi [Vigna unguiculata (L.) Walp.], tratado com óleos essenciais e fixos, no controle de Callosobruchus maculatus (Fabricius, 1775) (Coleoptera, Chrysomelidae, Bruchinae) Influence of the storage period of cowpea [Vigna unguiculata (L.) Walp.] treated with essential and fixed oils, for the control of Callosobruchus maculatus (Fabricius, 1775) (Coleoptera, Chrysomelidae, Bruchinae)

Compostos secundários obtidos de plantas podem ser utilizados no controle de Callosobruchus maculatus, como uma tática alternativa potencial aos inseticidas sintéticos. Foram testados óleos essenciais (Cymbopogon martini Roxb., Piper aduncum L., Piper hispidinervum C.DC., Melaleuca sp., Lippia gracillis Shau) e fixos (Helianthus annus L., Sesamum indicum L., Gossypium hirsutum L., Glycine max L. e Caryocar brasiliense Camb.), na concentração de 50µl/20g, de acordo com estudos anteriores. Grãos de caupi, cv. Sempre Verde, foram impregnados com os óleos, em recipientes de vidro e submetidos à agitação manual por dois minutos. Cada parcela de 20g foi infestada com oito fêmeas de C. maculatus com 0 a 48h de idade, durante quatro dias. Os óleos foram avaliados logo após a impregnação e aos 30, 60, 90 e 120 dias de armazenamento. Na primeira avaliação, todos os óleos essenciais provocaram 100% de mortalidade e para os óleos fixos, a mortalidade variou entre 35% (G. hirsutum) e 67,5% (G. max). Com o prolongamento do período de armazenamento, houve um aumento do número de ovos viáveis e de insetos emergidos, exceto para P. aduncum. Em relação aos óleos fixos, S. indicum, G. max, G. hirsutum e C. brasiliense foram os mais eficientes até os 30 dias de armazenamento. Os resultados indicam que os óleos testados na concentração de 50µl/20g apresentam baixo efeito residual, com exceção de P. aduncum, que foi efetivo durante todo o período de armazenamento.<br>The secondary compounds extracted from plants are considered potential alternative to synthetic insecticides in the control of agricultural pests. Essential oils (Cymbopogon martini Roxb., Piper aduncum L., P. hispidinervum C.DC., Melaleuca sp. and Lippia gracillis Shau) and fixed oils (Helianthus annus L., Sesamum indicum L., Gossypium hirsutum L., Glycine max L. and Caryocar brasiliense Camb.) at the concentration of 50µl/20g were tested according to previous studies. Samples of cowpea cv. Sempre Verde were impregnated with these oils in glass recipients and submitted to manual agitation for two minutes. Each plot of 20g was infested with eight females of C. maculatus up to 48 hours old, during four days. The oil efficiency was evaluated right after the impregnation and after 30, 60, 90 and 120 days of storage. In the first evaluation, all essential oils caused 100% of mortality and the fixed oils caused low mortality, varying from 35% (G. hirsutum) to 67,5% (G. max). With longer storage period, there was an increase in the number of viable eggs and emerged insects, except for P. aduncum. Among the fixed oils, S. indicum, G. max, G. hirsutum and C. brasiliense were the most efficient up to 30 days of storage. The results showed the low residual effect of the tested oils for the control of C. maculatus, excep P. aduncum, which was efficient throughout the 120 days of storage