With Eugene Koonin, we propose a concept of “the selfish ribosome”, under which evolution of life is viewed as a ribosomal takeover, where the ribosome evolved to consume most of the cell’s resources, while other cellular componentry ensures the propagation of the ribosome. arxiv.org/abs/2602.23268

Elegant study from @erinhuiting.bsky.social @jbdsf.bsky.social on CBASS phage inhibition without loss of cell viability. Especially interesting to see this phenotype with a CapV membrane-targeting effector and evidence for 3'3'-cGAMP transport!

www.biorxiv.org/content/10.6...

1/5
Happy by a recent biorxiv pre-print about DARNA (PD-T7-3) anti-phage defense system. This system is activated by binding to ssDNA, presented by phage SSB, to cleave tRNA in the anti-codon loop.
www.biorxiv.org/content/10.6...

New preprint on Detectrons from @jihoon-han.bsky.social! These are programmable biosensors for RNA that produce DNA barcodes in the presence of their target RNA. Check out Jihoon's quoted thread and the preprint for more:
www.biorxiv.org/content/10.6...

We found a new mode by which bacteria deplete NAD+ to protect from phages. And then we found how phages overcome this defense

Discovered by talented biochemist Dr Ilya Osterman, read the preprint: tinyurl.com/Narp-ap

A thread 🧵

Preprint out: We characterise PUA-Cal-HAD, a widespread bacterial antiphage defence family. An infection cue switches a preassembled complex into an immune filament that drains dNTPs via a coupled two-enzyme cascade, and phage DNA mimics can block filament assembly (anti-polymerisation).

Most plasmids described in E. coli are small compared to the megaplasmids we identified here! Check out the preprint if you want to learn about these mysterious large elements and their potential functions 🧬. I’m very grateful to have had the opportunity to work on this in @banfieldlab.bsky.social

RNA-triggered Cas12a3 cleaves tRNA tails to execute bacterial immunity - Nature Cas12a3 nucleases constitute a distinct clade of type V CRISPR–Cas bacterial immune systems that preferentially cleave the 3′ tails of tRNAs after recognition of target RNA to induce growth arres...

Our paper is out! Hiding in plain sight among Cas12a nucleases, Cas12a3 cleaves not its RNA target but the 3′ ends of tRNA. Huge thanks to all who made this possible, especially the Beisel lab, Biao & Dirk for the structure, & @sebastianglatt.bsky.social for all things tRNA. doi.org/10.1038/s415...

The EMBO Gold Medal 2025 was awarded to Tanmay Bharat and David Bikard: https://www.embo.org/press-releases/embo-gold-medal-2025-awarded-to-tanmay-bharat-and-david-bikard/ 🧪

At #CellBio2025, the EMBO Gold Medal was handed over to David Bikard in recognition of his pioneering work on #GeneEditing.

Structural basis of Retron-Eco8-mediated anti-phage defense https://www.biorxiv.org/content/10.64898/2025.12.04.692459v1

The Ppl protein senses 3′-hydroxyl DNA overhangs and NTP depletion to halt phage infection Xu et al. reveal that the Ppl defense system protects bacteria from phages by acting as a “double-check” security system. It requires two simultaneous phage-induced stresses to activate, a sophisticated mechanism that ensures effective immunity while preventing premature abortive infection.

Online Now: The Ppl protein senses 3′-hydroxyl DNA overhangs and NTP depletion to halt phage infection Online now:

Structural mechanism of the Retron-Eco7 anti-phage defense system - Nature Communications The Retron-Eco7 is a genetic element involved in anti-phage defense that encodes two effector proteins (PtuA and PtuB) and cleaves the host tRNA. Here, the authors solved the Retron-Eco7 complex struc...

www.nature.com/articles/s41...

Structural mechanism of the Retron-Eco7 anti-phage defense system

⭐ NAR Breakthrough! ⭐
🦠 New study shows phage X1 hijacks Yersinia's enterocolitica flagellum to inject its DNA directly into the cytosol. Yersinia, though, strikes back!
🦠 A fascinating look at the #dualrole of #flagella in #viralentry and #bacterialimmunity.
🧬 Read more: doi.org/10.1093/nar/...

Bacteriophage genome-wide transposon mutagenesis https://www.biorxiv.org/content/10.1101/2025.11.23.690004v1

🚨Preprint alert - this is a big one! We transfer the revolutionary power of TnSeq to bacteriophages.

Our HIDEN-SEQ links the "dark matter" genes of your favorite phage to any selectable phenotype, guiding the path from fun observations to molecular mechanisms.

A thread 1/8

Systematic mapping of bacteriophage gene essentiality with HIDEN‑SEQ The constant arms race of bacteriophages and their bacterial hosts has inspired major breakthroughs in biotechnology and shaped phages as fierce predators with great clinical potential to fight multid...

First the link to the preprint: www.biorxiv.org/content/10.1...

I’m excited to share my recent postdoc work. Here, we interrogate how different phage infection outcomes (productive vs. restrictive) affect the expression of phage defense systems. We find that a restricted infection not only inhibits the phage but also induces increased immune protein abundance.

Surviving phage attack dynamically regulates bacterial immunity to defeat counterdefenses https://www.biorxiv.org/content/10.1101/2025.11.13.688357v1

Cap1 forms a cyclic tetra-adenylate-induced membrane pore during the type III-A CRISPR-Cas immune response https://www.biorxiv.org/content/10.1101/2025.11.13.688252v1

Scalable and systematic hierarchical virus taxonomy with vConTACT3 Viruses are key players in diverse ecosystems, but studying their impacts is technically and taxonomically challenging. Taxonomic complexities derive from undersampling, diverse DNA and RNA genomes wi...

🚨vConTACT3 preprint live!🚨(Peer Review soon...!)

vConTACT3 delivers a unified, scalable, and transparent framework for genome-based virus taxonomy — helping translate big viral data into systematic classification.

🔗 Read the preprint: doi.org/10.1101/2025...

Improvements details below 👇

Bacteria can sense when a virus starts shredding their genome — by detecting methylated mononucleotides.
Here’s the story of how we discovered the Metis defense system 👇
www.biorxiv.org/content/10.1...

A membrane-bound nuclease directly cleaves phage DNA during genome injection https://www.biorxiv.org/content/10.1101/2025.11.03.685801v1

Phage SSB detection by retron Eco8 msDNA unleashes nuclease-mediated immunity The cryo-EM structure of the retron Eco8 system reveals an autoinhibited 4:4:4 complex of RT, msDNA, and OLD nuclease. Phage SSB binding to msdDNA unleashes non-specific nuclease activity to restrict ...

I’m thrilled to share our Retron Eco8 paper published in Molecular Cell today. Thanks all Fu lab members and our collaborators.
👉Phage SSB detection by retron Eco8 msDNA unleashes nuclease-mediated immunity. www.cell.com/molecular-ce...

Been working on a really strange retron bacterial immune system, here's the preprint: www.biorxiv.org/content/10.1...
Type VI retrons are unlike any other. Phage infection triggers reverse transcription of a DNA fragment that activates translation of a toxin to kill the infected cell.

Taxonomically different symbiotic communities of sympatric Arctic sponge species show functional similarity with specialization at species level | mSystems Sponges are regarded among the earliest multicellular organisms and the most ancient examples of animal-bacterial symbiosis. The study of host-microbe interactions in sponges has advanced rapidly due ...

It’s finally out!
Our paper on the bacterial symbionts of three White Sea sponges is here.
A story that began in 2016 has reached its last chapter… or has it? We hope that by the time you finish our hefty tome — maybe around 2034 — we’ll release the sequel.
journals.asm.org/doi/10.1128/...

Two intensive sampling periods of oyster-associated vibrio and their phage, 4 years apart, and many surprises. Despite being washed by the Atlantic, wide tides, and vibrio (almost?) disappearing most of the year, we can find the exact same virulent phages 4 years later (down to 0 SNP)! preprint👇

Happy that the final version of our Lamassu work @yli18smc.bsky.social is now out:

www.nature.com/articles/s41...

Thanks again to our awesome collaborators @mblokesch.bsky.social and David and co and Mark Szczelkun and @steven-shaw.bsky.social and the DCI Lausanne @fbm-unil.bsky.social

Expanding the Landscape of BREX Diversity: Uncovering Multi-Layered Functional Frameworks and Identification of Novel BREX-Related Defense Systems Despite extensive scrutiny of BREX systems, several overarching questions persist regarding the functional modalities of individual components and the collective mechanistic framework underlying their...

Wow, a significant expansion of what we know about BREX.

www.biorxiv.org/content/10.1...

Ecological constraints foster both extreme viral-host lineage stability and mobile element diversity in a marine community Phages are typically viewed as very rapidly evolving biological entities. Little is known, however, about whether and how phages can establish long-term genetic stability. We addressed this eco-evolut...

Phages evolve fast, or do they?
In oysters, some stay identical for years.
With >1,200 phages & 600 Vibrio genomes, we reveal long-term stability and new mobile elements.
Proud of this collaborative work across our teams (Roscoff-UdeM and @epcrocha.bsky.social www.biorxiv.org/cgi/content/...

How do SMC complexes load onto DNA to get ready for loop extrusion?

@roisnehamelinf.bsky.social & co discovered that Wadjet, an SMC complex involved in bacterial DNA immunity, performs some impressive molecular gymnastics 🤸‍♂️🤸‍♂️🤸‍♂️.

Check out the new paper: www.cell.com/molecular-ce...