Biology subjects

Auclair, J.

Publications and source records attributed to Auclair, J..

2 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↗

bioRxiv2019

Shigella flexneri adherence factor expression in in vivo-like conditions

The Shigella species are Gram-negative, facultative intracellular pathogens that invade the colonic epithelium and cause significant diarrheal disease. Despite extensive research on the pathogen, comprehensive understanding of how Shigella initiates contact with epithelial cells remains unknown. Shigella maintains many of the same Escherichia coli adherence gene operons; however, at least one critical gene component in each operon is currently annotated as a pseudogene in reference genomes. These annotations, coupled with a lack of structures upon microscopic analysis following growth in laboratory media, have led the field to hypothesize that Shigella is unable to produce fimbriae or other \"traditional\" adherence factors. Nevertheless, our previous analyses have demonstrated that a combination of bile salts and glucose induce both biofilm formation and adherence to colonic epithelial cells. Through a two-part investigation, we first utilized various transcriptomic analyses to demonstrate that S. flexneri strain 2457T adherence gene operons are transcribed. Subsequently, we performed mutation, electron microscopy, biofilm, infection, and proteomic analyses to characterize three of the structural genes. In combination, these studies demonstrate that despite the gene annotations, S. flexneri 2457T uses adherence factors to initiate biofilm formation as well as epithelial cell contact. Furthermore, host factors, namely glucose and bile salts in the small intestine, offer key environmental stimuli required for proper adherence factor expression in S. flexneri. This research may have a significant impact on vaccine development for Shigella and further highlights the importance of utilizing in vivo-like conditions to study bacterial pathogenesis.\n\nImportanceBacterial pathogens have evolved to regulate virulence gene expression at critical points in the colonization and infection processes to successfully cause disease. The Shigella species infect the epithelial cells lining the colon to result in millions of cases of diarrhea and a significant global health burden. As antibiotic resistance rates increase, understanding the mechanisms of infection are vital to ensure successful vaccine development. Despite significant gains in our understanding of Shigella infection, it remains unknown how the bacteria initiate contact with the colonic epithelium. Most pathogens harbor multiple adherence factors to facilitate this process, but Shigella was thought to have lost the ability to produce these factors. Interestingly, we have identified conditions that mimic some features of gastrointestinal transit and enable Shigella to express adherence factors. This work highlights aspects of genetic regulation for Shigella adherence factors and may have a significant impact on future vaccine development.

microbiology↗