What is the benefit of forming bundles? We don't fully understand this yet. Maybe it protects fibers from phage, degradation, or shearing? Or, it could promote biofilm formation, similar to what is seen in archaic chaperone-usher pathway pili. Or, it might enable electron transfer between cells.

This electroactive bacterium has a long doubling time (~1 d). It probably allocates a lot energy expenditure to make those nanowire bundles. Interestingly, hemes within a single fiber are well insulated, and the heme-heme distance between fibers seems too far to allow electrons to jump between them.

A Bundled Antiparallel Cytochrome Nanowire Structure Suggests Roles in Cell-Cell Electron Transfer and Biofilm Formation Long-range extracellular electron transfer enables respiring microbes to use minerals, other organisms, or electrodes as electron acceptors by transporting electrons microns away from the cell surface...

Check out the fancy anti-parallel cytochrome nanowire bundles structure we've solved. This structure originates from a bacterium, strain name WTL (well-to-live), isolated by the Bond group from the Soudan Underground Iron Mine, located 713 m below the surface. www.biorxiv.org/content/10.1...

Our Pyrodictium cannulae paper is out in its final form! Cannulae assemble into calcium-stabilized tubular filaments stable at 100 °C—a unique archaeal cell–cell connection. Led brilliantly by @mikesleutel.bsky.social & @vinceconticello.bsky.social.

www.nature.com/articles/s41467-025-64120-8

Lab’s first paper is out!! We show the first structures of #Asgard #chromatin by #cryo-EM 🧬❄️
Asgard histones form closed and open hypernucleosomes. Closed are conserved across #Archaea, while open resemble eukaryotic H3–H4 octasomes and are Asgard-specific. More here: www.cell.com/molecular-ce...

Finally, this pilus was reported to be conductive many years ago. However, our structure shows no molecular basis for this, and our bulk measurements confirm the pili are not conductive. It's not surprising—why would a photosynthetic bacterium need to adopt the anaerobic respiration lifestyle?

Intriguingly, we also showed this pilus can bind microcystin on its surface! 😜 This binding may be achieved by a unique glycosylation pattern, allowing the bacteria to enrich these toxins, which could potentially aid in their survival.

These pili are crucial for the bacteria to maintain its water column position. Since we lack genetic knockout tools, we temporarily sheared the pili off. Without them, the bacteria could no longer remain where they were. The cells remained viable, and the pili were regenerated after a few hours.

A family of tubular pili from harmful algal bloom forming cyanobacterium Microcystis aeruginosa - Nature Communications Ricca et al discover a new family of tubular pili in Microcystis aeruginosa, a harmful algal bloom-forming cyanobacterium. These pili are crucial for buoyancy by forming cell micro-colonies, which inc...

First time posting on Bluesky! 🥳 We discovered a new pilus family in cyanobacteria. The pilin has a novel protein fold that forms a super-tight double-layer tube. Similar gene clusters exist in a few cyanobacterial orders. A great collaboration with John and others! www.nature.com/articles/s41...

Cannulae paper published in final form. Thanks to the many collaborators and to the reviewers. @jerryknowsnothing.bsky.social @mikesleutel.bsky.social @vikramalva.bsky.social

rdcu.be/eKVlI

A family of tubular pili from harmful algal bloom forming cyanobacterium Microcystis aeruginosa Nature Communications - Ricca et al discover a new family of tubular pili in Microcystis aeruginosa, a harmful algal bloom-forming cyanobacterium. These pili are crucial for buoyancy by forming...

I missed the original share on this article since I was locked out of my Bluesky account due to algorithmic impotence. Hate when that happens. Really cool structure from @jerryknowsnothing.bsky.social and co-authors. rdcu.be/eHQ1N

Two distinct archaeal type IV pili structures formed by proteins with identical sequence - Nature Communications Type IV pili (T4P) are long surface appendages assembled from small pilin proteins that participate in diverse functions such as adhesion and biofilm formation in archaea. Here, the authors show that ...

Archaeal pili are wild! In #archaeon Saccharolobus islandicus the same adehesive type 4 pilin exists in 4 different conformations forming two structurally very different pili. Collaboration with the groups of @jerryknowsnothing.bsky.social and Ed Egelman. www.nature.com/articles/s41...

Have a look at our paper on a new group of pleomorphic viruses infecting marine hyperthermophilic #archaea of the class Archaeoglobi. The virus coexists in a stable relationship with its host. Congrats to Diana Baquero and Eduardo Bignon. @ISMEJ doi.org/10.1093/isme...