Biology subjects

Rossignol, M.

Publications and source records attributed to Rossignol, M..

3 recordsLinked to original sources

bioRxiv2020

Mosquito densoviruses: the revival of a biological control agent against urban Aedes vectors of arboviruses

Urban Aedes mosquitoes are vectors of many viruses affecting human health such as Dengue, Chikungunya and Zika viruses. Insecticide resistance and environmental toxicity risks hamper the effectiveness of chemical control against these mosquito vectors. Alternative control methods, such as the use of mosquito-specific entomopathogenic viruses should be explored. Numerous studies have focused on evaluating the potential of different densoviruses species as biological control agent. However, knowledge on the extent of inter- and intra-specific variations in the susceptibility of Aedes mosquitoes to infection by different densoviruses remains insufficient. In this study, we compared infection and mortality rates induced by the Aedes albopictus densovirus 2 in different strains of Aedes albopictus and Aedes aegypti mosquitoes. The two Aedes species were different in terms of susceptibility to viral infection. Under laboratory conditions, Aedes albopictus densovirus 2 appeared more virulent for the different strains of Aedes aegypti tested than for those of Aedes albopictus. In addition, we also found significant intra-specific variation in infection and mortality rates. Thus, although even if Aedes albopictus densoviruses could be powerful biocontrol agents used in the management of urban Aedes populations, our results also call into question the use of single viral isolate as biocontrol agents.

microbiology↗

bioRxiv2019

Sub-lethal insecticide exposure affects host biting efficiency of Kdr-resistant Anopheles gambiae

AO_SCPLOWBSTRACTC_SCPLOWThe massive use of insecticide-treated nets (ITNs) has drastically changed the environment for malaria vector mosquitoes, challenging their host-seeking behaviour and biting success. Here, we investigated the effect of a brief exposure to an ITN on the biting behaviour of Anopheles mambiae mosquitoes and the interaction between such behaviour and the kdr mutation that confers resistance to pyrethroids. To this aim, we developed a video assay to study the biting behaviour of mosquitoes with similar genetic background, but different kdr locus genotypes (SS i.e. homozygous susceptible, RS i.e. heterozygous and RR i.e. homozygous resistant), after a brief exposure to either control untreated nets or one of two types of pyrethroid-treated nets (deltamethrin or permethrin). In presence of untreated nets, the kdr mutation did not influence mosquito blood feeding success but caused differences in feeding and prediuresis durations and blood meal size. Exposure to deltamethrin ITN decreased the blood feeding success rate of RR and RS mosquitoes, whereas in presence of permethrin ITN, the kdr mutation increased the blood-feeding success of mosquitoes. Exposure to the two types of pyrethroid-treated nets reduced feeding duration, prediuresis duration and blood meal size of all three genotypes. Our study demonstrates a complex interaction between insecticide exposure and the kdr mutation on the biting behavior of mosquitoes, which may substantially impact malaria vector fitness and disease transmission.

animal behavior and cognition↗

bioRxiv2017

Initiation of DNA replication requires actin dynamics and formin activity

Nuclear actin influences transcription in a manner dependent on its dynamics of polymerisation and nucleocytoplasmic translocation. Using human somatic cells and transcriptionally-silent Xenopus egg extracts, we show that actin dynamics is also required for DNA replication. We identify many actin regulators in replicating nuclei from Xenopus egg extracts, and show that in human cells, nuclear actin filaments form in early G1 and disassemble prior to S-phase. In either system, treatments that stabilise nuclear actin filaments abrogate nuclear transport and initiation of DNA replication. Mechanistically, actin directly binds RanGTP-importin complexes and disruption of its dynamics hinders cargo release. This prevents both nuclear pore complex (NPC) formation and active nuclear transport, which we show is required throughout DNA replication. Nuclear formin activity is required for two further steps: loading of cyclin-dependent kinase (CDK) and proliferating cell nuclear antigen (PCNA) onto chromatin and initiation of DNA replication. Thus, actin dynamics and formins are involved in several nuclear processes essential for cell proliferation.

cell biology↗