Biology subjects

Duchateau, L.

Publications and source records attributed to Duchateau, L..

3 recordsLinked to original sources

bioRxiv2018

Genome-wide gene expression profiling reveals that cuticle alterations and P450 detoxification are associated with pyrethroid resistance in Anopheles arabiensis populations from Ethiopia

BACKGROUNDVector control is the main intervention in malaria control and elimination strategies. However, the development of insecticide resistance is one of the major challenges for controlling malaria vectors. Anopheles arabiensis populations in Ethiopia showed resistance against both DDT and the pyrethroid deltamethrin. Although a L1014F target-site resistance mutation was present in the voltage gated sodium channel of investigated populations, the levels of resistance and biochemical studies indicated the presence of additional resistance mechanisms. In this study, we used genome-wide transcriptome profiling by RNAseq to assess differentially expressed genes between three deltamethrin and DDT resistant An. arabiensis field populations (Tolay, Asendabo, Chewaka) and two susceptible strains (Sekoru and Mozambique).\n\nRESULTSBoth RNAseq analysis and RT-qPCR showed that a glutathione-S-transferase, gstd3, and a cytochrome P450 monooxygenase, cyp6p4, were significantly overexpressed in the group of resistant populations compared to the susceptible strains, suggesting that the enzymes they encode play a key role in metabolic resistance against deltamethrin or DDT. Furthermore, a gene ontology enrichment analysis showed that expression changes of cuticle related genes were strongly associated with insecticide resistance, although this did not translate in increased thickness of the procuticle.\n\nCONCLUSIONOur transcriptome sequencing of deltamethrin/DDT resistant An. arabiensis populations from Ethiopia suggests non-target site resistance mechanisms and pave the way for further investigation of the role of cuticle composition in resistance.

molecular biology↗

bioRxiv2018

The effect of silencing immunity related genes on longevity in the naturally occurring Anopheles arabiensis mosquito population of Southwest Ethiopia

BackgroundIn the fight against malaria, vector control remains the most important tool, butit is now severely constrained by the spread of insecticide or behavioral resistance by mosquito populations. Therefore, new vector control tools are warranted. Such novel tools include anti-mosquito vaccines or mosquito genetic modifications targeting the mosquito midgut homeostasis and reducing the mosquito lifespan beyond a stage they can transmit malaria.\n\nMethodsWe assessed the effect of RNA interference silencing of the midgut homeostasis regulators FN3D1, FN3D2, FN3D3, GPRGR9 and PGRPLC3 in populations of Anopheles arabiensis reared at nearly natural setting. We monitored the survival of gene-silenced mosquitoes and assessed the load of their midgut microbiota using flow cytometry. The effect of gene silencing was modeled by the Cox proportional hazards frailty model, and bacterial counts were first log transformed and then compared by a mixed model.\n\nResultSignificantly higher mortality rates were observed for the FN3D1 (Hazard ratio =1.64, P=0.004), FN3D3 (HR=1.79, P<0.001) and GPRGr9 silenced mosquitoes (HR=2.00, P<0.001) as compared to a control group injected with dsRNA against a non-related bacterial gene LacZ. The bacterial load ratios for all target gene silenced mosquitoes compared to control mosquitoes were above 1, with the highest value for FN3D1 equal to 2.66 (95%CI: [0.94;7.57]) but no statistically significant difference could be demonstrated. Interestingly, there was a strong correlation (r=0.61) between the mortality hazard ratio and the bacterial count ratio of the gene-silenced mosquitoes. Increased mortality rates were reversed when the gene-silenced mosquitoes were treated with antibiotic mixtures suggesting that gut microbiota play a key role in the observed reduction of mosquito survival.\n\nConclusionWe demonstrate that interfering with the expression of theFN3D1, FN3D3 or GPRGr9 genes can cause a significant reduction of the longevity of An. arabiensis mosquitoes due to the disruption of the mosquito gut homeostasis.

immunology↗

bioRxiv2017

An optimized strategy for cloning-based locus-specific bisulfite sequencing PCR

In this methods paper, we describe a successful strategy to investigate locus-specific methylation by cloning-based bisulfite sequencing. We cover sample handling, DNA isolation, DNA quality control before bisulfite conversion, bisulfite conversion, DNA quality control after bisulfite conversion, in silico identification of CpG islands, methylation-independent bisulfite sequencing PCR (BSP) assay design, methylation-independent BSP, cloning strategy, sequencing and data analysis. Methods that are described nicely elsewhere will not be covered in detail. Instead, the focus will be on tips/tricks and new methods/strategies used in this protocol, including quality control assessment of the DNA before and after bisulfite conversion and a pooled cloning strategy to reduce time, costs and effort during this step. In addition we comment on dealing with bias and improving overall protocol efficiency.

genomics↗