Mathieu Sicard

Mathieu Sicard
Université de Montpellier | UM1 · Institut des Sciences de l’Évolution Montpellier (ISEM)

PhD

About

100
Publications
7,945
Reads
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1,466
Citations
Citations since 2017
47 Research Items
835 Citations
2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
Additional affiliations
September 2006 - August 2013
Université de Poitiers
Position
  • Maitre de conférences
September 2004 - August 2005
University of Münster
Position
  • PostDoc Position

Publications

Publications (100)
Preprint
Full-text available
This study developed a new bioinformatics pipeline to acquire all the different copies of multi-copy gene families based on Oxford Nanopore Technologies sequencing of PCR products. We used this pipeline to acquire the sequences of highly similar copies of the cidA and cidB genes present in the genomes of Wolbachia pipientis (wPip) bacteria infectin...
Article
Wolbachia are widespread endosymbiotic bacteria that manipulate the reproduction of arthropods through a diversity of cellular mechanisms. In cytoplasmic incompatibility (CI), a sterility syndrome originally discovered in the mosquito Culex pipiens, uninfected eggs fertilized by sperm from infected males are selectively killed during embryo develop...
Article
Full-text available
Microbial communities are known to influence mosquito lifestyles by modifying essential metabolic and behavioral processes that affect reproduction, development, immunity, digestion, egg survival, and the ability to transmit pathogens. Many studies have used 16S rRNA gene amplicons to characterize mosquito microbiota and investigate factors that in...
Article
Wolbachia endosymbionts commonly induce cytoplasmic incompatibility, making infected males’ sperm lethal to the embryos unless these are rescued by the same bacterium, inherited from their mother. Causal genes were recently identified but two families of mechanistic models are still opposed. In the toxin-antidote model, interaction between the toxi...
Preprint
Full-text available
Microbial communities are known to influence mosquito lifestyles by modifying essential metabolic and behavioral processes that affect reproduction, development, immunity, digestion, egg survival, and ability to transmit pathogens. Many studies have used 16S rRNA gene amplicons to characterize mosquito microbiota and investigate factors that influe...
Article
Full-text available
Mosquitoes not only transmit human and veterinary pathogens called arboviruses (arthropod-borne viruses) but also harbor mosquito-associated insect-specific viruses (mosquito viruses) that cannot infect vertebrates. In the past, studies investigating mosquito viruses mainly focused on highly pathogenic interactions that were easier to detect than t...
Article
Full-text available
In arthropods, Wolbachia endosymbionts induce conditional sterility, called cytoplasmic incompatibility (CI), resulting from embryonic lethality. CI penetrance (i.e., embryonic death rate) varies depending on host species and Wolbachia strains involved. All Culex pipiens mosquitoes are infected by the endosymbiotic alphaproteobacteria Wolbachia wPi...
Article
Full-text available
Wolbachia are the most widespread endosymbiotic bacteria in animals. In many arthropod host species, they manipulate reproduction via several mechanisms that favour their maternal transmission to offspring. Among them, cytoplasmic incompatibility (CI) promotes the spread of the symbiont by specifically decreasing the fertility of crosses involving...
Article
Full-text available
The inadequacy of the standard mosquito control strategies calls for ecologically safe novel approaches, like the use of biological agents such as the endosymbiotic α‐proteobacteria Wolbachia or insect‐specific viruses (ISVs). Understanding the ecological interactions between these “biocontrol endosymbionts” is thus a fundamental step to achieve. W...
Article
Full-text available
There are many documented examples of viral genes retained in the genomes of multicellular organisms that may in some cases bring new beneficial functions to the receivers. The ability of certain ichneumonid parasitic wasps to produce virus-derived particles, the so-called ichnoviruses (IVs), not only results from the capture and domestication of s...
Article
Full-text available
Viruses of the Parvoviridae family infect a wide range of animals including vertebrates and invertebrates. So far, our understanding of parvovirus diversity is biased towards medically or economically important viruses mainly infecting vertebrate hosts, while invertebrate infecting parvoviruses-namely densoviruses-have been largely neglected. Here,...
Article
Full-text available
Endosymbiotic Wolbachia bacteria are to date considered the most widespread symbionts in arthropods and are the cornerstone of major biological control strategies. Such a high prevalence, is based on the ability of Wolbachia to manipulate their hosts’ reproduction. One manipulation called “cytoplasmic incompatibility (CI)” is based on the death of...
Article
Wolbachia bacteria inhabit the cells of about half of all arthropod species, an unparalleled success stemming in large part from selfish invasive strategies. Cytoplasmic incompatibility (CI), whereby the symbiont makes itself essential to embryo viability, is the most common of these and constitutes a promising weapon against vector-borne diseases....
Article
To protect humans and domestic animals from mosquito borne diseases, alternative methods to chemical insecticides have to be found. Pilot studies using the vertically transmitted bacterial endosymbiont Wolbachia were already launched in different parts of the world. Wolbachia can be used either in Incompatible Insect Technique (IIT), to decrease mo...
Article
Culex pipiens densovirus (CpDV), a single stranded DNA virus, has been isolated from Culex pipiens mosquitoes but differs from other mosquito densoviruses in terms of genome structure and sequence identity. Its transmission from host to host, the nature of its interactions with both its host and host's endosymbiotic bacteria Wolbachia are not known...
Preprint
Full-text available
Culex pipiens densovirus (CpDV), a single stranded DNA virus, has been isolated from Culex pipiens mosquitoes but differs from other mosquito densoviruses in terms of genome structure and sequence identity. Its transmission from host to host, the nature of its interactions with both its host and host′s endosymbiotic bacteria Wolbachia are not known...
Article
Full-text available
Wolbachia are maternally inherited endosymbiotic bacteria, widespread among arthropods thanks to host reproductive manipulations that increase their prevalence into host populations. The most commonly observed manipulation is cytoplasmic incompatibility (CI). CI leads to embryonic death in crosses between i) infected males and uninfected females an...
Data
Presentation of the ten C. pipiens lines used in this study. (DOCX)
Data
The different crosses from which the CI cellular phenotype in C. pipiens was studied. Three different types of crosses were performed to study the cellular phenotype responsible for embryonic death in sterile crosses: i) sterile crosses between males and females infected with different Wolbachia strains, ii) sterile crosses between infected males a...
Data
mod and resc profiles of the lines used in crosses experiments. mod profiles were determined by crossing males from the four Mal lines with the females of the 4 ref-cytotypes lines Atyame et al. (2014). resc profiles were determine by crossing females of the five Fem lines with males of the 4 ref-cytotypes lines. Mal lines harbored wPip strains wit...
Data
cidA copy number in the wPip strains infecting the four Mal lines. cidA copy number was measured by quantitative PCR as the ratio between the number of copies of the Wolbachia cidA gene and the Wolbachia wsp gene. The colored dots represent the cidA copy number per wPip genome in a male and the red strips represent the average cidA copy number per...
Data
Wolbachia cidA and cidB expression of the four Mal lines estimated with Real Time Quantitative PCR. (CSV)
Data
Proportion of unhatched developed embryos from CI crosses involving either infected or uninfected (TC) females. Proportion of unhatched developed embryos are given as the mean proportion measured on fifty eggs for 10 rafts per cross (500 eggs observed per cross) ± standard deviation. No unhatched developed embryos were found in any of the seven dif...
Data
Accession numbers. Accession numbers for cidA cidB variants analyzed in S2 and S3 Figs. (DOCX)
Data
Unhatched developed embryos are haploid. Restriction profile of kdr PCR products by RsaI enzyme from single mosquito extracted DNA. M: molecular weight marker. 1 wPipIII-Slab line; 2/3: wPipIV-Ichkeul 13 line; 4/5: eggs-raft containing non-viable developed embryos from a CI cross between ♂ Slab x ♀ Ichkeul 13 (embryos display only maternal markers)...
Data
Repertoires of CidA protein variants in the four Mal line wPip strains. Protein sequences alignment of the CidA variants found in the four Wolbachia strains wPipI-Tunis, wPipI-Utique, wPipII-Lavar and wPipIII-Slab (Mal lines). The first sequence is used as a reference to determine the polymorphic region. For more clarity, only polymorphic positions...
Data
cidB expression level in the wPip strains infecting the four Mal lines. cidB expression was measured by quantitative PCR as the ratio between the Wolbachia cidB gene expression and the Wolbachia wsp gene expression. The colored dots represent the cidB expression level per wPip genome in a male and the red strips represent the average cidB expressio...
Data
cidA/cidB expression level in the wPip strains infecting the four Mal lines. cidA/cidB expression levels was measured by quantitative PCR as the ratio between the number of copies of the Wolbachia cidA gene and the Wolbachia cidB gene. The colored dots represent the cidA/cidB expression level per wPip genome in a male and the red strips represent t...
Data
Wolbachia testes density of the four Mal lines estimated with Real Time Quantitative PCR. (CSV)
Data
Wolbachia cidA and cidB copy number of the four Mal lines estimated with Real Time Quantitative PCR. (CSV)
Data
Explanation of the nomenclature used in this paper. (DOCX)
Data
cidA/cidB copy number in the wPip strains infecting the four Mal lines. cidA/cidB copy number was measured by quantitative PCR as the ratio between the number of copies of the Wolbachia cidA gene and the Wolbachia cidB gene. The colored dots represent the cidA/cidB copy number per wPip genome in a male and the red strips represent the average cidA/...
Data
cidA expression level in the wPip strains infecting the four Mal lines. cidA expression was measured by quantitative PCR as the ratio between the Wolbachia cidA gene expression and the Wolbachia wsp gene expression. The colored dots represent the cidA expression level per wPip genome in a male and the red strips represent the average cidA expressio...
Data
Proportion of unhatched developed haploid embryos of performed CI crosses. (CSV)
Data
The repertoire of CidB protein variants in the four Mal line wPip strains. Protein sequences alignment of the CidB variants found in the four Wolbachia strains wPipI-Tunis, wPipI-Utique, wPipII-Lavar and wPipIII-Slab (Mal lines). The first sequence is used as a reference to determine the polymorphic region. For more clarity, only polymorphic positi...
Data
Correlation between cidB variants diversity in wPip genomes and CI cellular intensity. Lighter gray bar plot accounts for the 10 crosses involving males from Lavar and Utique lines hosting wPip, which harbor 2 different variants of cidB in their genomes, while darker gray bar plot accounts for the 10 crosses involving males from Tunis and Slab line...
Data
cidB copy number in the wPip strains infecting the four Mal lines. cidB copy number was measured by quantitative PCR as the ratio between the number of copies of the Wolbachia cidB gene and the Wolbachia wsp gene. The colored dots represent the cidB copy number per wPip genome in a male and the red strips represent the average cidB copy number per...
Article
Full-text available
In the originally published HTML and PDF versions of this Article, gel images in Figures 7c and 8c were not prepared as per the Nature journal policy. These figure panels have now been corrected in both the PDF and HTML versions of the Article. In Fig. 7c, the lane labelled ‘Ha’ was inappropriately duplicated to represent the lane labelled ‘Ich13’....
Article
Full-text available
Background Wolbachia are maternally transmitted bacteria that can manipulate their hosts’ reproduction causing cytoplasmic incompatibility (CI). CI is a sperm-egg incompatibility resulting in embryonic death. Due to this sterilising effect on mosquitoes, Wolbachia are considered for vector control strategies. Important vectors for arboviruses, fila...
Article
Full-text available
Culex pipiens mosquitoes are infected with Wolbachia (wPip) that cause an important diversity of cytoplasmic incompatibilities (CIs). Functional transgenic studies have implicated the cidA-cidB operon from wPip and its homolog in wMel in CI between infected Drosophila males and uninfected females. However, the genetic basis of the CI diversity indu...
Article
Full-text available
Vertical transmission mode is predicted to decrease the virulence of symbionts. However, Wolbachia, a widespread vertically transmitted endosymbiont, exhibits both negative and beneficial effects on arthropod fitness. This ‘Jekyll and Hyde’ behaviour, as well as its ability to live transiently outside host cells and to establish new infections via...
Article
Vertically transmitted symbionts can distort their host's reproduction in order to increase their own transmission. In Wolbachia and some other symbionts, a particular distortion of this sort is feminization, whereby genetic males, which cannot transmit symbionts, are converted during development into functional females, which do transmit symbionts...
Article
Full-text available
Several microsatellite markers have already been developed for different terrestrial isopod species such as Armadillidium vulgare, A. nasatum and Porcellionides pruinosus. In all these species, the endosymbiont Wolbachia has a feminizing effect that generates a female bias in sex ratio and reduces the number of reproductive males. Thus this can pot...
Article
Full-text available
Wolbachia is an intracellular α-proteobacterium which is transmitted vertically from mother to offspring but also frequently switches horizontally from one host to another. Our hypothesis is based on the role of immune cells and the organs that produce them, the hematopoietic organs (HOs), as primordial niches for the propagation of Wolbachia via h...
Article
Full-text available
Wolbachia is a vertically transmitted endosymbiont whose radiative success is mainly related to various host reproductive manipulations that led to consider this symbiont as a conflictual reproductive parasite. However, lately, some Wolbachia have been shown to act as beneficial symbionts by protecting hosts against a broad range of parasites. Stil...
Article
Full-text available
The Wolbachia are intracellular endosymbionts widely distributed among invertebrates. These primarily vertically transmitted α-proteobacteria have been intensively studied during the last decades due to their intriguing interactions with hosts, ranging from reproductive manipulations to mutualism. To optimize their vertical transmission from mother...
Article
Full-text available
In the terrestrial isopod species Porcellio dilatatus, unidirectional Cytoplasmic Incompatibility (CI) between two morphs (P. d. dilatatus and P. d. petiti) caused by a Wolbachia strain (wPet) infecting the morph P. d. petiti has been previously described by experiments initiated four decades ago. Here, we studied another Wolbachia that has been re...
Article
Full-text available
Terrestrial isopods can be killed by some entomopathogenic bacteria among Xenorhabdus and Photorhabdus species even with no or very limited multiplication. This suggests that toxemia and not septicemia is the major cause of entomopathogenic bacteria pathogenicity against these crustaceans. In this paper, we revealed that the injection of stationary...
Article
Full-text available
The alphaproteobacteria Wolbachia pipientis are among the most common and widespread symbionts in the animal world. Their vertical transmission mode is predicted to favour genotypes with low virulence. On the contrary, horizontal transfers of Wolbachia from one host to another have been shown to possibly increase the symbiont virulence. This situat...
Article
Full-text available
The endosymbiont Wolbachia pipientis infects various hosts in which it navigates vertically from mothers to offspring. However, horizontal transfers of Wolbachia can occur between hosts. The virulence of the horizontally acquired Wolbachia can change in the new host as it has been illustrated by the case of the feminizing strain wVulC from the wood...
Article
Full-text available
The alpha-proteobacteria Wolbachia are the most widespread endosymbionts in arthropods and nematodes. Mainly maternally inherited, these so-called sex parasites have selected several strategies that increase their vertical dispersion in host populations. However, the lack of congruence between the Wolbachia and their host phylogenies suggests frequ...
Data
Behavioral film showing the symptoms encountered in P. d. dilatatus after the injection of the wVulC strain. Animals exhibited surfacing behavior, lack of mobility and several symptoms as seizures, leg tremors and paralysis. (MP4)
Article
Full-text available
Wolbachia are widespread endosymbionts found in a large variety of arthropods. While these bacteria are generally transmitted vertically and exhibit weak virulence in their native hosts, a growing number of studies suggests that horizontal transfers of Wolbachia to new host species also occur frequently in nature. In transfer situations, virulence...
Article
Full-text available
While parasites are likely to encounter several potential intermediate hosts in natural communities, a parasite's actual range of compatible hosts is limited by numerous biological factors ranging from behaviour to immunology. In crustaceans, two major components of immunity are haemocytes and the prophenoloxidase system involved in the melanisatio...
Article
Full-text available
Ecological factors modulate animal immunocompetence and potentially shape the evolution of their immune systems. Not only environmental parameters impact on immunocompetence: Aging is one major cause of variability of immunocompetence between individuals, and sex-specific levels of immunocompetence have also been frequently described. Moreover, a g...
Article
Full-text available
Coevolution in mutualistic symbiosis can yield, because the interacting partners share common interests, to coadaptation: hosts perform better when associated with symbionts of their own locality than with others coming from more distant places. However, as the two partners of a symbiosis might also experience conflicts over part of their life cycl...
Article
Full-text available
A new entomopathogenic nematode, Steinernema boemarei n. sp., is described from southern France. Morphological, molecular (28S and ITS rDNA sequence data) and cross-hybridisation studies were used for diagnostics and identification purposes. Both molecular and morphological data indicate that the new species belongs to the 'glaseri-group' of Steine...
Article
Competition among different parasite genotypes within a host is predicted to affect virulence. The direction of this effect, however, depends critically on the mechanisms that parasites use to compete or to cooperate with each other. One mechanism that bacteria use to compete with each other is via the production of bacteria-killing toxins, called...
Article
Isolation and identification of native nematode-bacterial associations in the field are necessary for successful control of endemic pests in a particular location. No study has yet been undertaken to recover and identify EPN in metropolitan France. In the present paper, we provide results of a survey of EPN and their symbiotic bacteria conducted in...
Article
In this study, we evaluated the effect of entomopathogenic nematodes (EPNs) Steinernema carpocapsae, Steinernema feltiae and Heterorhabditis bacteriophora, symbiotically associated with bacteria of the genera Xenorhabdus or Photorhabdus, on the survival of eight terrestrial isopod species. The EPN species S. carpocapsae and H. bacteriophora reduced...