Biology subjects

Henri, H.

Publications and source records attributed to Henri, H..

12 recordsLinked to original sources

bioRxiv2026

Nutritional Anthelmintics: Chicory Reconfigures the Equine Holobiont Across Microbial, Parasitic, and Host Scales

Anthelmintic resistance in cyathostomins is escalating worldwide, threatening equine health and highlighting the need for sustainable, ecology-based parasite control strategies. Chicory (Cichorium intybus, Puna II) has emerged as a promising antiparasitic forage, yet its broader effects on the equine holobiont, parasites, microbiota, and host physiology remain poorly understood. We conducted a 32-day longitudinal grazing trial in young horses to assess how chicory affects parasitological outcomes, gut microbial ecology, nemabiome composition, behaviour, and host physiological and immune responses. Twenty-six naturally infected Anglo-Arabian horses were monitored weekly, with 13 grazing a chicory-based sward and 13 grazing a permanent pasture. Clinical parameters, body weight, and serum biochemistry remained stable across treatments, indicating that chicory was well tolerated. Immune profiles showed limited variation, although IL-10 increased in chicory-fed horses, suggesting subtle immune modulation. Behavioural observations revealed no signs of discomfort and indicated slightly enhanced social interactions in the chicory group. Chicory grazing produced a marked reduction in cyathostomin egg excretion, accompanied by species-specific shifts in nemabiome composition. Several cyathostomin taxa, including Cylicocyclus ashworthi, C. leptostomus, and C. nassatus, declined in chicory-fed horses, whereas certain Cylicostephanus spp increased, indicating differential sensitivity rather than uniform suppression. Concomitantly, chicory induced profound ecological changes in the gut microbiota, including reduced alpha diversity, increased beta dispersion, and destabilised individual microbial trajectories. Several bacterial lineages, particularly Oscillospiraceae, Clostridiaceae, Lachnospiraceae, and Bacteroidales, were differentially enriched, reflecting a functional reorganisation of the intestinal ecosystem. Together, these findings demonstrate that chicory reduces parasite fitness, reshapes nemabiome composition, and alters gut microbial ecology while maintaining host physiological stability. Chicory thus emerges as a promising ecological tool for parasite control, capable of modulating the equine holobiont in ways that complement and potentially reduce reliance on conventional anthelmintic strategies. However, because its effects on gut microbial ecology remain uncertain, and may include shifts resembling dysbiosis, future studies are needed to monitor microbial dynamics more closely and clarify the long-term ecological consequences of chicory grazing. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=136 SRC="FIGDIR/small/737212v1_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@7b7367org.highwire.dtl.DTLVardef@d5914aorg.highwire.dtl.DTLVardef@135ad65org.highwire.dtl.DTLVardef@10b0322_HPS_FORMAT_FIGEXP M_FIG C_FIG

systems biology↗

bioRxiv2024

High fidelity genetic markers for sexing Cannabis sativa seedlings

The uses of Cannabis sativa, a dioecious species with an XY sex chromosome system, are varying from fiber and oil to cannabinoids, among others. In most cases, males are undesirable and the sexual dimorphism at immature plants is too subtle for reliable phenotypic sexing, making genetic approaches promising. In this technical note, we present a multiplex PCR-mix, that includes two markers of Y-specific coding regions and one autosomal control marker. This PCR-mix, tested across 12 hemp-type cultivars, encompassing approximately 200 individuals, achieved a 99.5% success rate in identifying the sex of C. sativa seedlings.

genomics↗

bioRxiv2024

Intricate interactions between antiviral immunity and transposable element control in Drosophila

Transposable elements (TEs) are parasite DNA sequences that are controlled by RNA interference pathways in many organisms. In insects, antiviral immunity is also achieved by the action of small RNAs. In the present study, we analyzed the impacts of an infection with Drosophila C Virus (DCV) and found that TEs are involved in a dual response: on the one hand TE control is released upon DCV infection, and on the other hand TE transcripts help the host reduce viral replication. This discovery highlights the intricate interactions in the arms race between host, genomic parasites, and viral pathogens. Significance statementTransposable elements (TEs) are widespread components of all genomes. They were long considered as mere DNA parasites but are now acknowledged as major sources of genetic diversity and phenotypic innovations. Using Drosophila C virus, here we show that TEs are at the center of defense and counter-attack between host and virus. On the one hand, TE control is released upon viral infection, and on the other hand, TE transcripts help the host reduce viral replication. To our knowledge, this is the first time such a complex host-pathogen interaction involving TEs is shown.

evolutionary biology↗

bioRxiv2023

A major 6 Mb superlocus is involved in pyrethroid resistance in the common bed bug Cimex lectularius

In the last few years, the bed bug Cimex lectularius has been an increasing problem world-wide, mainly due to the development of insecticide resistance to pyrethroids. The characterization of resistance alleles is a prerequisite to improve surveillance and resistance management. To identify genomic variants associated with pyrethroid resistance in Cimex lectularius, we compared the genetic composition of two recent and resistant populations with that of two ancientsusceptible strains using a genome-wide pool-seq design. We identified a large 6 Mb "superlocus" showing particularly high genetic differentiation and association with the resistance phenotype. This superlocus contained several clustered resistance genes, and was also characterized by a high density of structural variants (inversions, duplications). The possibility that this superlocus constitutes a resistance "supergene" that evolved after the clustering of alleles adapted to insecticide and after reduction in recombination is discussed.

evolutionary biology↗

bioRxiv2022

Genomic Changes During the Evolution of the Coxiella Genus Along the Parasitism-Mutualism Continuum.

The Coxiellaceae family is composed of five genera showing lifestyles ranging from free-living to symbiosis. Among them, Coxiella burnetii is a well-known pathogen causing Q fever in humans. This bacterium presents both intracellular (parasitic) and environmental (resistant) forms. Recently, several environmental Coxiella genomes have been reported, among which several have come from intracellular mutualistic symbionts of ticks, termed Coxiella-like endosymbionts. We sequenced two new Coxiella-LE genomes from Dermacentor marginatus (CLEDm) and Ornithodoros maritimus (CLEOmar) ticks, the latter belonging to the C. burnetii lineage. Using these newly sequenced Coxiella-LEs and 43 Coxiellaceae genomes, we conducted comparative genomic and phylogenomic analyses to increase our knowledge of C. burnetii pathogenicity and the emergence of Coxiella-LEs. Results highlight the probably parasitic nature of the common ancestor of the Coxiellaceae. Indeed, the virulence factor Dot/Icm T4 Secretion System is present in most, but not all, Coxiellaceae. Whereas it is part of a putative pathogenic island in C. burnetii, it has been entirely lost or inactivated in Coxiella-LEs, suggesting its importance in pathogenesis. Additionally, we found that a Sha/Mrp antiporter was laterally acquired in the C. burnetii lineage. This antiporter might be involved in alkali resistance and the development of the resistant form that is able to persist in the environment for long periods of time. The Sha operon is eroded or absent in Coxiella-LEs. Finally, we found that all Coxiella representatives produce B vitamins and co-factors indicating a pre-adaptation of Coxiella to mutualism with hematophagous arthropods. Accordingly, the ancestor of C. burnetii and Coxiella-LEs was likely a parasitic bacterium able to manipulate its host cell and to produce vitamins and co-factors for its own use.

microbiology↗

bioRxiv2022

Targeting RNA:Protein Interactions with an Integrative Approach Leads tothe Identification of Potent YB-1 Inhibitors

RNA-binding proteins are promising targets for developing new molecules of therapeutic interest. Nevertheless, targeting RNA:Protein interfaces is hampered by the lack of methods able to detect these interactions in cells while being amenable to High Content Screening. Here, we adapt the microtubule bench assay to score small molecules targeting interactions of endogenous mRNA with a specific protein in cells and demonstrate its robustness by targeting YB-1 (YBX-1 gene), a mRNA-binding protein involved in cancer progression and resistance to chemotherapy. The implementation of an integrative approach led to the identification of 22 hits validated by NMR and MD simulations of which 11 were found to significantly interfere with the binding of mRNA to YB-1 in cells at low micromolar concentrations. One of our leads is P1, an FDA-approved PARP-1 inhibitor. This work shows the potential of our integrative approach and paves the way for the development of RNA:Protein Interaction inhibitors.

biophysics↗

bioRxiv2021

Analyses of symbiotic bacterial communities in the plant pest Bemisia tabaci reveal high prevalence of Hemipteriphilus asiaticus on the African continent

AO_SCPLOWBSTRACTC_SCPLOWMicrobial symbionts are widespread in insects and some of them have been associated to adaptive changes. Primary symbionts (P-symbionts) have a nutritional role that allows their hosts to feed on unbalanced diets (plant sap, wood, blood). Most of them have undergone genome reduction, but their genomes still retain genes involved in pathways that are necessary to synthesize the nutrients that their hosts need. However, in some P-symbionts, essential pathways are incomplete and secondary symbionts (S-symbionts) are required to complete parts of their degenerated functions. The P-symbiont of the phloem sap-feeder Bemisia tabaci, Candidatus Portiera aleyrodidarium, lacks genes involved in the synthesis of vitamins, cofactors, and also of some essential amino-acids. Seven S-symbionts have been detected in the B. tabaci species complex. Phenotypic and genomic analyses have revealed various effects, from reproductive manipulation to fitness benefits, notably some of them have complementary metabolic capabilities to Candidatus Portiera aleyrodidarium, suggesting that their presence may be obligatory. In order to get the full picture of the symbiotic community of this pest, we investigated, through metabarcoding approaches, the symbiont content of individuals from Burkina Faso, a West African country where B. tabaci induces severe crop damage. While no new putative B. tabaci S-symbiont was identified, Candidatus Hemipteriphilus asiaticus, a symbiont only described in B. tabaci populations from Asia, was detected for the first time on this continent. Phylogenetic analyses however reveal that it is a different strain than the reference found in Asia. Specific diagnostic PCRs showed a high prevalence of these S-symbionts and especially of Candidatus Hemipteriphilus asiaticus in different genetic groups. These results suggest that Candidatus Hemipteriphilus asiaticus may affect the biology of B. tabaci and provide fitness advantage in some B. tabaci populations.

evolutionary biology↗

bioRxiv2020

The disproportionate effect of drift on a hypervariable master regulator of density

Symbiosis is a continuum of long-term interactions ranging from mutualism to parasitism, according to the balance between costs and benefits for the protagonists. The density of endosymbionts is, in both cases, a key factor that determines both the transmission of symbionts and the host extended phenotype, and is thus tightly regulated within hosts. However, the evolutionary and molecular mechanisms underlying bacterial density regulation are currently poorly understood. In this context, the symbiosis between the fruit fly and its intracellular bacteria Wolbachia (wMelPop strain) is particularly interesting to study. Although vertically transmitted, the symbiont is pathogenic, and a positive correlation between virulence and wMelPop density is observed. In addition, the number of repeats of a bacterial genomic region -Octomom-is positively correlated with Wolbachia density, underlying a potential genetic mechanism that controls bacterial density. Interestingly, the number of repeats varies between host individuals, but most likely also within them. Such genetic heterogeneity within the host could promote conflicts between bacteria themselves and with the host, notably by increasing within-host competition between symbiont genotypes through a process analogous to the tragedy of the commons. To characterize the determinisms at play in the regulation of bacterial density, we first introgressed wMelPop in different genetic backgrounds of D. melanogaster, and found different density levels and Octomom copy numbers in each host lineage. To determine whether such variations reflect a host genetic determinism on density regulation through Octomom copy number selection, we replicated the introgressions and performed reciprocal crosses on the two Drosophila populations with the most extreme density levels. In both experiments, we detected an absence of directionality in the patterns of infection, associated with a strong instability of these patterns across generations. Given that bacterial density was highly correlated with Octomom copy numbers in all experiments, these results rather suggest a strong influence of drift and a random increase in the frequency of certain bacterial variants. We then discuss how drift, both on the symbiont population during transmission and on the host population, could limit the efficiency of selection in such a symbiotic system, and the consequences of drift on the regulation of density and composition of bacterial populations.

evolutionary biology↗

bioRxiv2020

Development of genetic markers for sexing Cannabis sativa seedlings

Cannabis sativa is a dioecious plant with a XY system. Only females produce cannabinoids in large amount. Efficient male removal is an important issue for the cannabis industry. We have recently identified the sex chromosomes of C. sativa, which opens opportunities for developing universal genetic markers for early sexing of C. sativa plants. Here we selected six Y-linked markers and designed PCR primers, which were tested on five hemp cultivars both dioecious and monoecious. We obtained promising results, which need to be extended using a larger number of individuals and a more diverse set of cultivars, including THC producing ones.

plant biology↗

bioRxiv2020

Drosophila suzukii oxidative stress response involves Jheh gene cluster but not transposable elements

The study of the mechanisms involved in adaptation remains a timely issue, particularly in the context of global changes. To better understand these mechanisms of rapid adaptation, invasive species are a good model because they are subjected to new and/or different environmental factors. Using different lines of different geographical origin of the invasive pest Drosophila suzukii, we characterized the phenotypic response to oxidative stress. Subsequently, we tested the involvement of the Jheh gene cluster in this response and the possible role of transposable elements. We show that the resistance to oxidative stress of the lines appears to be related to their invasive status and we confirm the role of the Jheh gene cluster in this response. We have not identified any transposable elements in this gene region that could influence the expression of the gene. Summary statementThe responses to oxidative stress of the invasive species, Drosophila suzukii, show variability between genotypes related to their invasion status. The genes of the juvenile hormone epoxide hydrolase cluster are involved in this response.

evolutionary biology↗

bioRxiv2020

Experimental evolution of virulence and associated traits in a Drosophila melanogaster - Wolbachia symbiosis

AO_SCPLOWBSTRACTC_SCPLOWEvolutionary theory predicts that vertically transmitted symbionts are selected for low virulence, as their fitness is directly correlated to that of their host. In contrast with this prediction, the Wolbachia strain wMelPop drastically reduces its Drosophila melanogaster host lifespan at high rearing temperatures. It is generally assumed that this feature is maintained because the D. melanogaster-wMelPop symbiosis is usually not exposed to environmental conditions in which the symbiont is virulent. To test this hypothesis, we submitted wMelPop-infected D. melanogaster lines to 17 generations of experimental evolution at a high temperature, while enforcing late reproduction by artificial selection. The fly survival was measured at different time points, as well as two traits that have been proposed to be causally responsible for wMelPop virulence: its relative density and the mean number of copies of octomom, an 8-genes region of the Wolbachia genome. We hypothesised that these conditions (high temperature and late reproduction) would select for a reduced wMelPop virulence, a reduced wMelPop density, and a reduced octomom copy number. Our results indicate that density, octomom copy number and virulence are correlated to each other. However, contrary to our expectations, we could not detect any reduction in virulence during the course of evolution. We discuss the significance of our results with respect to the evolutionary causes of wMelPop virulence.

evolutionary biology↗

bioRxiv2019

A high-throughput segregation analysis identifies the sex chromosomes of Cannabis sativa

Cannabis sativa-derived tetrahydrocannabinol (THC) production is increasing very fast worldwide. C. sativa is a dioecious plant with XY chromosomes, and only females (XX) are useful for THC production. The C. sativa sex chromosomes sequence would improve early sexing and better management of this crop; however, the C. sativa genome projects failed to identify the sex chromosomes so far. Moreover, dioecy in the Cannabaceae family is ancestral, C. sativa sex chromosomes are potentially old and thus very interesting to study as little is known about the last steps of sex chromosome evolution in plants. Here we RNA-sequenced a C. sativa family (2 parents and 10 male and female offspring) and performed a segregation analysis for all C. sativa genes using the probabilistic method SEX-DETector. We identified >500 sex-linked genes. Mapping of these sex-linked genes to a C. sativa genome assembly identified a single chromosome pair with a large non-recombining region. Further analysis of the >500 sex-linked genes revealed that C. sativa has a strongly degenerated Y chromosome and represents the oldest plant sex chromosome system documented so far. Our study revealed that old plant sex chromosomes can have large non-recombining regions and be very differentiated and still be of similar size (homomorphic).

genomics↗