Biology subjects

Fabre, L.

Publications and source records attributed to Fabre, L..

5 recordsLinked to original sources

bioRxiv2026

Phage-Inducible Chromosomal Jumbo Islands (PICJIs) spreading antimicrobial resistance, host-adaptation factors and defense systems, a novel satellite family of nucleus-forming Chimalliviridae

Phage satellites are mobile genetic elements that depend on helper bacteriophages to promote their own dissemination. Here, we identified a novel family of large satellites, named Phage-Inducible Chromosomal Jumbo Islands (PICJIs), that are widespread in Escherichia coli and Salmonella enterica among diverse hosts, worldwide. These largest satellites to date (71.6 {+/-} 15.8 kbp) are specifically transduced by the persistent jumbo bacteriophage Goslarvirus of the nucleus-forming Chimalliviridae family. Furthermore, PICJIs carried numerous accessory genes associated with clinically relevant antimicrobial resistances, host-adaptation, and several anti-phage defense systems.

microbiology↗

bioRxiv2026

Tracking emotional interference over time: Differential effects of dorsolateral and ventromedial prefrontal stimulation

Although a substantial body of evidence has demonstrated that emotional interference affects cognitive performance, relatively little is known about its temporal evolution and the respective brain regions underlying its regulation. The present study investigated the temporal dynamics of emotional interference and the contribution of prefrontal regions involved in its regulation. Forty-eight participants completed a 2-back task and a Set-switching task under neutral and negative emotional conditions while receiving sham, dorsolateral prefrontal cortex (dlPFC), or ventromedial prefrontal cortex (vmPFC) stimulation. Stimulation was administered either online during task performance or after a 5 min pre-task period. Consistent with previous findings, negative emotions impaired executive performance, particularly during high-demand updating conditions. Critically, time-resolved analyses revealed that emotional interference evolved dynamically throughout task performance and was differentially modulated by prefrontal stimulation. The most consistent stimulation effects emerged after approximately 10 minutes of cumulative stimulation exposure and varied as a function of the stimulation site, executive-control demands, and stimulation timing. Notably, online stimulation produced more consistent modulation than pre-task stimulation. Together, these findings indicate that both emotional interference and its neuromodulation are dynamic processes. More broadly, they suggest that the contribution of prefrontal control systems to emotion-cognition interactions may be better understood through their temporal evolution rather than through static measures of performance alone.

neuroscience↗

bioRxiv2024

An evolutionary-conserved VPS34-PIKfyve-TRPML1-Myosin II axis regulates the speed of amoeboid cell migration

Amoeboid cell migration is key to efficient T cell immunity. Spatial polarization of organelles within cells, including endo-lysosomes, is a prerequisite of migration. However, how ultrastructural polarization is linked to the signaling requirements governing T cell migration, remains unknown. Here we show that signaling molecules generated by endo-lysosome-localized kinases regulate velocity of amoeboid migration. Specifically, imaging of T cells identified accumulation of endo-lysosomes decorated with the lipid kinases VPS34-PIKfyve at the uropod of polarized cells. Activity of VPS34 and PIKfyve regulated speed, but not directedness, of migrating T cells. Mechanistically, PI(3,5)P2 generated by the sequential action of VPS34 and PIKfyve mediated Ca2+ efflux from lysosomes via the mucolipin TRP cation channel 1 (TRPML1), thus controlling activity of myosin IIA and hence the generation of propulsive force through retrograde actin flow. The VPS34-PIKfyve kinases also regulated velocity of myeloid cells, as well as of the amoeba Dictyostelium discoideum - establishing the axis as an evolutionary conserved speed control system of amoeboid cell migration. Graphical AbstractO_LIThe VPS34-PIKfyve axis is active on endo-lysosomes at the uropod of migrating T cells. C_LIO_LIVPS34 and PIKfyve promote myosin IIA activation and retrograde action flow. C_LIO_LIAmoeboid cell migration speed is controlled by VPS34 and PIKfyve via TRPML1. C_LIO_LIRegulation of amoeboid migration speed is a conserved function of the VPS34-PIKfyve axis. C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=83 SRC="FIGDIR/small/575998v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1b70e64org.highwire.dtl.DTLVardef@111d052org.highwire.dtl.DTLVardef@83bc24org.highwire.dtl.DTLVardef@b51931_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2022

Rapid emergence of extensively drug-resistant Shigella sonnei in France

Shigella sonnei, the main cause of bacillary dysentery in high-income countries, has become increasingly resistant to antibiotics. We monitored the antimicrobial susceptibility of 7,121 S. sonnei isolates collected in France between 2005 and 2021. We identified a dramatic increase in the proportion of extensively drug-resistant (XDR) isolates (i.e., simultaneously resistant to ciprofloxacin, third-generation cephalosporins and azithromycin), to 22.3% of all S. sonnei isolates in 2021. Our genomic analysis identified 13 different clusters of XDR isolates descended from a ciprofloxacin-resistant sublineage originating from South Asia. The 164 XDR isolates detected were resistant to azithromycin, principally through a pKSR100-like plasmid, and to third-generation cephalosporins through various genes and plasmids. This rapid emergence of XDR S. sonnei in different transmission networks, particularly among men who have sex with men, is a matter of concern, and good laboratory-based surveillance of Shigella infections will be crucial for informed decision-making and appropriate public health action.

microbiology↗

bioRxiv2021

Population structure analysis and laboratory monitoring of Shigella with a standardised core-genome multilocus sequence typing scheme: a validation study

The laboratory surveillance of bacillary dysentery is based on a standardised Shigella typing scheme that classifies Shigella strains into four serogroups and more than 50 serotypes on the basis of biochemical tests and lipopolysaccharide O-antigen serotyping. Real-time genomic surveillance of Shigella infections has been implemented in several countries, but without the use of a standardised typing scheme. We studied over 4,000 reference strains and clinical isolates of Shigella, covering all serotypes, with both the current serotyping scheme and the standardised EnteroBase core-genome multilocus sequence typing scheme (cgMLST). The Shigella genomes were grouped into eight phylogenetically distinct clusters, within the E. coli species. The cgMLST hierarchical clustering (HC) analysis at different levels of resolution (HC2000 to HC400) recognised the natural groupings for Shigella. By contrast, the serotyping scheme was affected by horizontal gene transfer, leading to a conflation of genetically unrelated Shigella strains and a separation of genetically related strains. The use of this cgMLST scheme will enhance the laboratory surveillance of Shigella infections.

genomics↗