Biology subjects

Nardini, L.

Publications and source records attributed to Nardini, L..

3 recordsLinked to original sources

bioRxiv2026

Anopheles resistance to deltamethrin can be caused by the increased abundance of an enteric Aeromonas taxon

The enteric bacteriome of Anopheles mosquito vector has been linked with its vectorial competence, however, its influence on insecticide resistance is poorly understood. We found that the depletion of the bacterial microbiome in susceptible Anopheles strains, resulting from antibiotic treatment, led to greater than 50% insecticide deltamethrin tolerance compared to untreated mosquitoes. Simultaneous inhibition of cytochrome P450 activity reverted the antibiotic-induced tolerance phenotype, indicating that the antibiotic-induced deltamethrin tolerance is P450-dependent. We found that the antibiotic treatment, while suppressing most enteric bacterial taxa, allowed proliferation of a particular antibiotic-tolerant Aeromonas taxon, most closely related to Aeromonas hydrophila. Increasing the abundance of this taxon in mosquitoes not treated with antibiotics phenocopied the tolerance phenotype, converting deltamethrin-susceptible Anopheles to deltamethrin-tolerant mosquitoes. Collectively, these results highlight a mechanistic interplay in Anopheles mosquitoes between antibiotic-induced enteric dysbiosis and cytochrome P450-mediated detoxification that promotes insecticide tolerance. This effect could influence mosquito vectorial capacity, especially in Africa, where auto-medication with antibiotics is highly prevalent.

microbiology↗

bioRxiv2020

Multistage and transmission-blocking targeted antimalarials discovered from the open-source MMV Pandemic Response Box

New chemical matter is needed to target the divergent biology associated with the different life cycle stages of Plasmodium. Here, we report the parallel screening of the Medicines for Malaria Venture Pandemic Response Box to identify multistage-active and stage-specific compounds against various life cycle stages of Plasmodium parasites (asexual parasites, stage IV/V gametocytes, gametes, oocysts and liver stages) and for endectocidal activity. Hits displayed unique chemotypes and included two multistage-active compounds, 16 asexual-targeted, six with prophylactic potential and ten gametocyte-targeted compounds. Notably, four structurally diverse gametocyte-targeted compounds with potent transmission-blocking activity were identified: the JmjC inhibitor ML324, two azole antifungals including eberconazole, and the antitubercular clinical candidate SQ109. Besides ML324, none of these have previously attributed antiplasmodial activity, emphasizing the success of de novo parallel screening against different Plasmodium stages to deliver leads with novel modes-of-action. Importantly, the discovery of such transmission-blocking targeted compounds covers a previously unexplored base for delivery of compounds required for malaria elimination strategies.

microbiology↗

bioRxiv2019

Influence of genetic polymorphism on transcriptional enhancer activity in the malaria vector Anopheles coluzzii

Enhancers are cis-regulatory elements that control most of the developmental and spatial gene expression in eukaryotes. Genetic variation of enhancer sequences is known to influence phenotypes, but the effect of enhancer variation upon enhancer functional activity and downstream phenotypes has barely been examined in any species. In the African malaria vector, Anopheles coluzzii, we identified a pilot set of candidate enhancers in the proximity of genes relevant for immunity, insecticide resistance, and development. The candidate enhancers were functionally validated using luciferase reporter assays, and their activity was found to be essentially independent of their physical orientation, a typical property of enhancers. All of the enhancer intervals segregated genetically polymorphic alleles, which displayed significantly different levels of functional activity, and inactive null alleles were also observed. Deletion mutagenesis and functional testing revealed a modular structure of positive and negative regulatory elements within the tested enhancers. The enhancer alleles carry genetic polymorphisms that also segregate in wild A. coluzzii populations in West Africa, indicating that enhancer variants with likely phenotypic consequences are frequent in nature. These results demonstrate the feasibility of screening for naturally polymorphic A. coluzzii enhancers that underlie important aspects of malaria transmission and vector biology.

genetics↗