Xavier Charpentier
labxc.bsky.social
Xavier Charpentier
@labxc.bsky.social
Group leader.
HGT in bacterial pathogens. Acinetobacter, Legionella. Natural transformation. AMR. MGEs.
Centre International de Recherche en Infectiologie
#microsky
Massive update of preprint with @polardlab.bsky.social!
Bacteria have evolved two systems to recombine extracellular DNA
www.biorxiv.org/content/10.1...
Kudos to lead authors Léo Hardy, Violette Morales and Clothilde Rousseau, and to outstanding Dalia's lab and @epcrocha.bsky.social
🧵⬇️
Two D-loop resolution systems enable natural genetic transformation in bacteria
Natural transformation is a widespread mechanism driving genetic exchanges in bacteria. It proceeds by the capture and internalization of exogenous DNA in linear single strands, ultimately integrated in the genome by homologous recombination. It is unknown how the RecA-directed D-loop intermediate of this dedicated recombination pathway is processed. We report that resolution of the transformation D-loop depends on two endonucleases of opposing phylogenetic distribution in bacteria. One is YraN, which has co-evolved and interacts with the ComM helicase, known to extend DNA recombination at the transformation D-loop. The other is CoiA, which is restricted to the Bacillota. CoiA is shown to be a resolvase of the transformation D-loop, extended by the RadA helicase in these species. We demonstrate that both YraN and CoiA act synergistically with their cognate helicases. These findings reveal that bacteria have evolved two helicase/nuclease pairs for the maturation and recombination extension of the transformation D-loop. ### Competing Interest Statement The authors have declared no competing interest. Agence Nationale de la Recherche, https://ror.org/00rbzpz17, ANR-20-CE12-0004, ANR-10-BLAN-1331, ANR-17-CE13-0031, ANR-22-CE44-0044, ANR-10-LABX-62-IBEID, PIA/ANR-16-CONV-0005 Fondation pour la Recherche Médicale, https://ror.org/04w6kn183, FDT202001010890 European Union's Horizon research and innovation programme. Marie Skłodowska-Curie Postdoctoral Fellowships, 101208987 National Institute of Health, USA, R35GM128674
www.biorxiv.org
January 16, 2026 at 4:24 PM
Reposted by Xavier Charpentier
My team at @cbitoulouse.bsky.social is recruiting a postdoc #bioinformatics with solid experience in metagenomic analyses.
Interest in evolution, ecology & MGEs is important.
The offer stands until the perfect candidate is found, and it could be you 🫵

🔁 🙏

#microSky #phagesky #UTIsky
@cnrs.fr
January 15, 2026 at 11:19 AM
Une opportunité unique de former des étudiants talentueux à la biologie des bactéries à l'ENS Lyon et mener des recherches sur les phages, l'immunité bactérienne, le transfert génétique horizontal (HGT) et/ou les éléments génétiques mobiles au sein du département de bactériologie du CIRI.
📢 Recruitment of an Associate Professor (Maître de conférences) in Bacteriology at CIRI and ENS de Lyon.
Research at @ciri-lyon.bsky.social @francoisrousset.bsky.social
@labxc.bsky.social
Anti-phage Immunity, Horizontal gene/ MGE transfer
📚 Teaching at ENS de Lyon within the Department of Biology.
January 13, 2026 at 2:01 PM
Reposted by Xavier Charpentier
Pleased to share our recent article in PNAS - a collaboration with @jessicaandreani.bsky.social & Pablo Radicella, with important roles played by many members of each team.

A tripartite protein complex promotes DNA transport during natural transformation in Firmicutes www.pnas.org/doi/10.1073/...
A tripartite protein complex promotes DNA transport during natural transformation in Firmicutes | PNAS
Natural genetic transformation is a conserved mechanism of bacterial horizontal gene transfer, which is directed entirely by the recipient cell and...
www.pnas.org
November 26, 2025 at 7:44 AM
Reposted by Xavier Charpentier
🚨#PhD studentship opportunity! Plasmids provide bacteria with antimicrobial resistance, but do they have more fundamental effects on behaviour? 🧫🦠💫🧟‍♂️

Apply for a 4y funded MRC DiMeN position with me and Jamie Wheeler @livuni-ives.bsky.social www.findaphd.com/phds/project...
MRC DiMeN Doctoral Training Partnership: Resistant zombies: how drug-resistance plasmids manipulate the behaviour of the opportunistic pathogen Pseudomonas aeruginosa at University of Liverpool on Fin...
PhD Project - MRC DiMeN Doctoral Training Partnership: Resistant zombies: how drug-resistance plasmids manipulate the behaviour of the opportunistic pathogen Pseudomonas aeruginosa at University of Li...
www.findaphd.com
November 18, 2025 at 9:38 AM
Reposted by Xavier Charpentier
Our new paper is out in @narjournal.bsky.social We show that natural transformation enables bacteria to shuffle integron cassettes, boosting their phenotypic diversity.
academic.oup.com/nar/article/... 1/5
Bacterial natural transformation drives cassette shuffling and simplifies recombination in chromosomal integrons
Abstract. Integrons act as biobanks of gene cassettes conferring functions crucial for bacterial defense, including protection against phages and antibioti
academic.oup.com
November 17, 2025 at 3:44 PM
Reposted by Xavier Charpentier
#ResultatScientifique 🔎 Certains gènes antiviraux humains partagent des défenses communes avec les bactéries, révélant une convergence évolutive surprenante 🧬
✍️ Alexandre Legrand et @lucievirevolte.bsky.social
📕 Nature Ecology and Evolution
buff.ly/Su0EdiU
Défenses immunitaires : une invention répétée au cours de l’évolution
Dans une étude publiée dans Nature Ecology and Evolution, des scientifiques montrent que les gènes SAMD9 et SAMD9L, a
www.insb.cnrs.fr
November 12, 2025 at 9:00 AM
Reposted by Xavier Charpentier
The ecology and evolution of bacterial immune systems'.

#phage #phagesky

A bunch of interesting reviews

royalsocietypublishing.org/doi/10.1098/...
Preface: the ecology and evolution of bacterial immune systems | Philosophical Transactions of the Royal Society B: Biological Sciences
Can't sign in? Forgot your password?
royalsocietypublishing.org
September 8, 2025 at 6:29 AM
Reposted by Xavier Charpentier
Delighted to share our recently published work!
Ever wondered how Klebsiella (and others) deals with capsule production’s costs ?
The paper: journals.asm.org/doi/10.1128/...
Thread👇
Phenotypic heterogeneity of capsule production across opportunistic pathogens | mBio
The polysaccharidic capsule is present in ~50% of species across the bacterial phylogeny, including all ESKAPE microorganisms, the six most significant multidrug-resistant (MDR) nosocomial pathogens. It is also an important virulence factor and a major ...
journals.asm.org
September 5, 2025 at 1:49 PM
Reposted by Xavier Charpentier
Here's our new broad review on the extended mobility of plasmids, about all mechanisms driving and limiting their transfer. From conjugation to conduction, phage-plasmids to hitchers, molecular to evolutionary dynamics, ecology to biotech. The state of affairs. 1/9 academic.oup.com/nar/article/...
July 23, 2025 at 7:35 AM
Reposted by Xavier Charpentier
New publication from our Lesterlin lab in collab with lab of @knutdrescher.bsky.social
We determined the spatiotemporal dissemination of conjugative plasmids within biofilms and found that they spread only in specific structural regions.

www.pnas.org/doi/10.1073/...
Biofilm architecture determines the dissemination of conjugative plasmids | PNAS
Plasmid conjugation is a contact-dependent horizontal gene transfer mechanism that significantly contributes to the dissemination of antibiotic res...
www.pnas.org
April 28, 2025 at 11:22 AM
Reposted by Xavier Charpentier
I'm very happy to share the last paper from my previous postdoc with the amazing @epcrocha.bsky.social! Thanks to the reviewers for their feedback, which improved our work!
#Plasmids #AMR #HorizontalGeneTransfer #Evolution
March 31, 2025 at 9:02 AM
Reposted by Xavier Charpentier
Travel awards for trainees and early-stage investigators to attend the 2025 Acinetobacter conference are available. Deadline for applications is April 30. Please rt.

events.faseb.org/event/1b872d...
Biology of Acinetobacter XIV
events.faseb.org
March 19, 2025 at 8:57 PM
Reposted by Xavier Charpentier
#TalentsCNRS 🥉 | Découvrez la vidéo de Lucie Etienne, chercheuse au Centre international de recherche en infectiologie et lauréate de la médaille de bronze du @cnrs.fr en 2024 !

@cnrsbiologie.bsky.social @lucievirevolte.bsky.social @ensdelyon.bsky.social @inserm.fr

www.youtube.com/watch?v=jE8b...
Lucie Etienne : décryptage des épidémies virales et des défenses immunitaires l TalentsCNRS
YouTube video by CNRS
www.youtube.com
February 18, 2025 at 3:03 PM
Reposted by Xavier Charpentier
Hello
L’École Thématique de Microbiologie Moléculaire (ETMM) fait son grand retour !
Rendez-vous du 6 au 10 octobre 2025
@ben-ezraty.bsky.social
Toujours à proximité de Marseille
En attendant, suivez-nous ici pour ne rien manquer :
@etmm.bsky.social
www.linkedin.com/showcase/%C3...
École Thématique de Microbiologie Moléculaire (ETMM) | LinkedIn
École Thématique de Microbiologie Moléculaire (ETMM) | 9 followers on LinkedIn. L’ETMM diffuse les avancées en microbiologie 🔬, réunissant experts et explorant concepts et thématiques clés 🥼
www.linkedin.com
February 6, 2025 at 1:58 PM
Reposted by Xavier Charpentier
🚨 Job alert 🚨 — are you interested in understanding how mobile genetic elements and defence systems shape bacterial genome evolution? 🧬 🧪 🧫 🦠 2x 5-year research positions available in experimental evolution @mermanchester.bsky.social Join us! #microsky
www.jobs.manchester.ac.uk/Job/JobDetai...
Research Associate in Experimental Evolution:Manchester
www.jobs.manchester.ac.uk
February 6, 2025 at 9:15 AM
Reposted by Xavier Charpentier
Out today @ Science: TIR signaling activates caspase-like immunity in bacteria

We report a new immune signaling molecule: N7-cADPR. Produced by phage-induced TIRs and activates a defensive bacterial caspase

Congrats Francois Rousset, Ilya Osterman and coauthors!

www.science.org/doi/10.1126/...
January 30, 2025 at 9:57 PM
Reposted by Xavier Charpentier
The contribution of natural transformation for the acquisition of novel genes has been notoriously difficult to quantify because it relies on recombination (which is affected by other processes). Here's a first estimate : doi.org/10.1101/2025... (for the very busy: 1-6% of gene gains) #MicroSky
January 27, 2025 at 1:11 PM
Reposted by Xavier Charpentier
What influence does evolutionary history have on basal transcriptomes? On transcriptomic response to drug? On genetic paths for drug resistance? On fitness tradeoffs? Check out our latest preprint to find out!

By @aleciarokes.bsky.social @asantoslopez.bsky.social

www.biorxiv.org/content/10.1...
History shapes regulatory and evolutionary responses to tigecycline in strains of Acinetobacter baumannii from the pre- and post-antibiotic eras
Evolutionary history encompasses genetic and phenotypic bacterial differences, but the extent to which history influences drug response and antimicrobial resistance (AMR) adaptation is unclear. Histor...
www.biorxiv.org
January 24, 2025 at 4:14 PM
Reposted by Xavier Charpentier
A really good comic by @jpjhall.bsky.social on bacteria that found a very engaging way to tell the story. #GraphicScience #SciComm #comics www.andthemicrobes.org/plasmid
- BIZARRE BACTERIA & PECULIAR PLASMIDS — And The Microbes
www.andthemicrobes.org
November 24, 2024 at 11:00 PM
Reposted by Xavier Charpentier
Incredible graphic - the myriad of ways that bacteria defend themselves against antibiotics.

14 resistance mechanisms, summarised by Idan Yelin & Roy Kishony in Cell

www.sciencedirect.com/science/arti...
November 13, 2024 at 12:46 PM
Reposted by Xavier Charpentier
Out today. The culmination of DETECTIVE led by the exceptional Rob. Longitudinal genomics of CRAb and identification of a new clone in China

www.nature.com/articles/s41...
Longitudinal genomics reveals carbapenem-resistant Acinetobacter baumannii population changes with emergence of highly resistant ST164 clone - Nature Communications
Carbapenem-resistant Acinetobacter baumannii is an important nosocomial pathogen that can cause outbreaks. In 2019, these authors conducted a genomic surveillance study of A baumannii in an intensive ...
www.nature.com
November 3, 2024 at 10:07 AM
Reposted by Xavier Charpentier
3-year Postdoctoral position available.

Topic: interbacterial competition mediated by T7SS.

Techniques: molecular biology, biochemistry, microbiology, CryoEM/ET and super-resolution fluorescence microscopy.

Applications (CV+publications)to [email protected]
Deadline: Jan 1st 2025
October 21, 2024 at 7:09 PM