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Julie Le Bris

@julielebris.bsky.social

1.2K followers 650 following 28 posts

PhD student interested in microbial evolution and ecology🧬 @Institut Pasteur #Klebsiella #MicroSky

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Julie Le Bris @julielebris.bsky.social · Sep 5

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

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Reposted by Julie Le Bris

FEMS Journals @femsjournals.bsky.social · 11h

A new subgroup of #CRISPR-associated transposons, V-K_V2, has been discovered in Nostocales #cyanobacteria by @cyanolab.bsky.social & colleagues 🧬. Its unique features suggest genetic mobility and V2 tracrRNAs are now included in the updated CRISPRtracrRNA tool.
buff.ly/gioIfEB

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Reposted by Julie Le Bris

FEMS Journals @femsjournals.bsky.social · 4d

Some #Pseudomonas aeruginosa strains naturally lack the major virulence system T3SS. 🦠 @inaattree.bsky.social & @cbuch.bsky.social labs reveal that avirulent isolates still produce valuable metabolites (e.g. rhamnolipids, elastase, pyoverdine)—making them promising for #biotech use.
buff.ly/JST7ZR1

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Reposted by Julie Le Bris

FEMS Journals @femsjournals.bsky.social · 11d

Phages are promising against antibiotic-resistant bacteria—but resistance can emerge. 🦠 New work from @baerboletta.bsky.social lab shows E. coli can resist phages in the lab, but in the gut that resistance comes at a cost: context is crucial for #PhageTherapy success.
buff.ly/NLOjnE2

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Reposted by Julie Le Bris

Jeunes microbiologistes de la SFM @jm-sfm.bsky.social · 14d

Cyril Anjou, 2e candidat au prix de thèse nous a présenté ses travaux sur les rôles physiologiques des systèmes thioredoxine de Clostridioides difficile, impliqués dans les étapes du cycle de vie de la bactérie, ainsi que sur l’intérêt thérapeutique potentiel de la modulation de leur expression.🦠

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Reposted by Julie Le Bris

Enninga Lab @enningalab.bsky.social · 20d

🦠 Mycobacteria aren't just tough, they're interior designers! 🦠 Check out our latest #preprint 🚨, led by our PhD student @camimille.bsky.social , where we show that #Mycobacterium tuberculosis builds secret cytoplasmic membranes to adapt its metabolism and sneak past immunity 🤫

Thread coming soon!

bioRxiv Microbiology @biorxiv-microbiol.bsky.social · 20d

Nitrate-responsive Mycobacterial Intracytoplasmic Membranes dampen Inflammation during Mycobacterium tuberculosis Infection https://www.biorxiv.org/content/10.1101/2025.09.17.676823v1

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Reposted by Julie Le Bris

FEMS Journals @femsjournals.bsky.social · 20d

New tool alert! 🚀 MCAAT uses de Bruijn graphs to detect #CRISPR arrays in #metagenomes, capturing data lost in assemblies. A step forward in uncovering the hidden diversity of CRISPR-Cas systems. By Talibli & Voß
buff.ly/QMX9yIe

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Reposted by Julie Le Bris

FEMS Journals @femsjournals.bsky.social · 23d

Archaea thrive in harsh niches that challenge DNA integrity. 🧬 In H. volcanii, Sailer et al. revealed Cas1 & Hel308a as new Microhomology-Mediated End Joining (MMEJ) players, expanding the toolkit for archaeal genomes repair.
buff.ly/lnyY7JF

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Reposted by Julie Le Bris

Benoit Pons @benoitjpons.bsky.social · Sep 4

How do bacteria choose what type of defences to use against phages? We explored that question in the last paper I worked on as a postdoc at the Uni of Exeter @uniofexeteresi.bsky.social with Stineke van Houte, Stefano Pagliara and Edze Westra (not on Bluesky)
doi.org/10.1098/rstb...

Phage provoke growth delays and SOS response induction despite CRISPR-Cas protection | Philosophical Transactions of the Royal Society B: Biological Sciences

Bacteria evolve resistance against their phage foes with a wide range of resistance strategies whose costs and benefits depend on the level of protection they confer and on the costs for maintainance....

doi.org

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Julie Le Bris @julielebris.bsky.social · 28d

Thanks Basile! 😊

Julie Le Bris @julielebris.bsky.social · 28d

Huge thanks to everyone involved : Hugo Varet @pasteur.fr, @epcrocha.bsky.social social and my amazing PhD director @olayarendueles.bsky.social

Julie Le Bris @julielebris.bsky.social · 28d

Here, we show a clear example of plug-and-play dynamics in the bacterial chromosome.
It explain the success and versatility of the Klebsiella capsule, giving insights into how complex traits can be repeatedly mobilized without extensive cellular rewiring.

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Julie Le Bris @julielebris.bsky.social · 28d

🏥 We show that the capsule’s modular architecture enables seamless horizontal transfer with preserved functionality. Specifically, K1 serotype acquisition drives hypermucoviscosity even without rmpA.

Julie Le Bris @julielebris.bsky.social · 28d

We observed minimal transcriptomic changes, minimal fitness costs and convergent adaptation to a specific environment rather than serotype-specific solutions, hinting for capsule locus modularity. 🧬

Julie Le Bris @julielebris.bsky.social · 28d

🦠 We found that capsule production is highly hierarchical, determined by the capsule type and the genetic background independently.

Julie Le Bris @julielebris.bsky.social · 28d

We swapped capsular loci in five different genetic backgrounds of the nosocomial pathogen Klebsiella pneumoniae. #phagesky #AMR

Julie Le Bris @julielebris.bsky.social · 28d

🧬 Beyond virulence, capsule changes shape host evolution and is tied to core metabolism. This suggests epistasis, yet their diversity and turnover argue for modularity. @klebclub.bsky.social #microsky

Julie Le Bris @julielebris.bsky.social · 28d

How complex functions, with important physiological and evolutionary impacts get repeatedly and efficiently transferred across genomes?
That’s what we explored using one of the fastest-evolving loci in Bacteria: the capsule locus.
The paper: www.biorxiv.org/content/10.1...
Thread👇

Serotype swapping in Klebsiella spp. by plug-and-play

Understanding how complex, multi-gene systems evolve and function across genetic backgrounds is a central question in molecular evolution. While such systems often impose costs through epistatic inter...

www.biorxiv.org

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Reposted by Julie Le Bris

Olaya Rendueles @olayarendueles.bsky.social · 29d

Check out @julielebris.bsky.social’s thread on our latest manuscript describing phenotypic heterogeneity in capsule production in Klebsiella & Acinetobacter @klebclub.bsky.social

This work started when I was still in @pasteur.fr & got finished in @cbitoulouse.bsky.social
#microsky #phagesky

Julie Le Bris @julielebris.bsky.social · Sep 5

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

journals.asm.org

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Julie Le Bris @julielebris.bsky.social · Sep 5

A big shout out to my PhD director @olayarendueles.bsky.social

And congratulations to everyone involved in this fascinating project! Sara, Lilibeth, Amandine and @epcrocha.bsky.social

Julie Le Bris @julielebris.bsky.social · Sep 5

Capsule heterogeneity appears as a bet-hedging strategy that could play a major role in shaping the alternation of the bacterial life cycle between the environment and pathogenesis by giving a small subpopulation reversible, useful traits.

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Julie Le Bris @julielebris.bsky.social · Sep 5

🏥 Such heterogeneity is also found in Acinetobacter spp.

Julie Le Bris @julielebris.bsky.social · Sep 5

Capsule production heterogeneity enables a subpopulation to escape from phages, relevant for phage therapy strategies but also impacting gene flow. 🧬

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Julie Le Bris @julielebris.bsky.social · Sep 5

🦠 Such heterogeneity varies across environment and contributes to increase the strain fitness.

Julie Le Bris @julielebris.bsky.social · Sep 5

We developed a method to quantify this capsule production heterogeneity in more than 150 Klebsiella spp. strain and found it widespread (mostly in classical strains!). 🕵

Julie Le Bris @julielebris.bsky.social · Sep 5

🔬Microscopy with India ink staining showed clonal cells make varying amounts of capsule—unlike P. fluorescence’ ON/OFF switch, it’s a continuous phenotype.

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