
Bacterial geneticist @HumboldtUni studying assembly and function of a fascinating nanomachine - the bacterial flagellum
Berlin, Germany
Joined December 2016
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How do bacteria build their flagella?
We’ve put together an animation of Salmonella flagellum assembly based on cryo-EM and X-ray structures.
From the membrane-embedded machinery to the growing filament, here’s how the parts come together, step-by-step.
Bacteria have immune systems to defend against their viruses.
This animation shows the proposed mechanism of the Zorya defense system from our work with @NMITaylorLab: a proton-driven membrane complex related to the bacterial flagellar stator.
doi.org/10.1038/s41586-024-0…
Can bacteria have too many flagella?
More flagella help Salmonella swim faster and spread farther, but building them slows growth.
In our new preprint, we quantify this trade-off and predict an optimum close to wild type.
📄 doi.org/10.64898/2026.08.20.…
We also made a longer animation illustrating the experiments and simulations behind the study, from flagellar gene expression and proteome allocation to bacterial growth and motility.
Watch the full 3-minute animation:
molmicro.hu-berlin.de/movies…
What makes flagella so expensive?
Surprisingly, our results suggest that most of the cost comes from building them, particularly synthesizing flagellin, rather than rotating the motors.
Increased investment in flagella also comes largely at the expense of ribosomes.
How does flagellar number affect bacterial swimming?
This simulation compares Salmonella with fewer (PproA) or more (PproB) flagella in liquid and an agarose-like environment.
Try it yourself:
molmicro.hu-berlin.de/motili…
Marc Erhardt retweeted
Salmonella-phage networks
Profiling >1,000 global Salmonella-phage interactions reveals layered resistance &high contribution of surface architecture to defense. Discover AppA, which blocks phage DNA packaging via mimicry of terminase assembly interface
cell.com/cell-host-microbe/f…
Marc Erhardt retweeted
The final version of our manuscript on TnSeq in bacteriophages (“HIDEN-SEQ”) is out today – if you have an interesting phage phenotype and want to know the underlying genetic basis, this one is for you! 1/3
PhD opening in my lab
@HumboldtUni
Join our DFG SPP 2389 project on bacterial biofilms & multicellularity.
Study how F-pili conjugation shapes biofilms using genetics, microfluidics & 3D imaging.
📅 Apply by 3 June 2026
🔗 hu.berlin/SPP2389-PhD
#PhD #Microbiology #Biofilms
🤖 Made with AI
Postdoc opening in my lab @HumboldtUni!
Join our Einstein Foundation-funded collaboration with the Hebrew University of Jerusalem on T3SS, spatial RNA localization, imaging & bacterial cell biology.
📅 Apply by 2 June 2026
🔗 hu.berlin/T3SSjob
#Postdoc #Microbiology
🤖 Made with AI
Marc Erhardt retweeted
Congratulations to first author @AritzRoa for his amazing work on how T4 delivers its genome and blocks other phages from injecting theirs 🥳 Check out his beautiful movie📽️ Thanks to all authors and collaborators MLNielsen and @AHarms485 tinyurl.com/2kvva646 #cryoEM #phage
Marc Erhardt retweeted
#MicrobiologyMonday: The bacterial flagellum is built through a hierarchical assembly process and powered by a dynamic motor capable of astonishing speeds. What's new in our understanding of these complex nanomachines? Find out in #MMBRJournal: asm.social/2HB
Marc Erhardt retweeted
A beautiful example of evolutionary innovation: Bacterial chemoreceptor was "reprogrammed" in pathogenic E. coli to control expression of flagellar genes instead of signalling through the chemotaxis pathway. embopress.org/doi/full/10.10…
Marc Erhardt retweeted
Out Now! The structure of the complete extracellular bacterial flagellum reveals the mechanism of flagellin incorporation bit.ly/4nqcNe9 #Microbiology #Bacteria #Flagellum
"The structure of the complete extracellular bacterial flagellum reveals the mechanism of flagellin incorporation"
Now published @NatureMicrobiol 🥳!
rdcu.be/eugWM
I'm excited to share the newest preprint of the lab... the structure of the complete extracellular flagellum, our most favourite bacterial nanomachine!
biorxiv.org/content/10.1101/…
A result of a very productive collaboration with @BergeronLab and @BeebyLab !
Marc Erhardt retweeted
Cold Spring Harbor Laboratory - absolutely humbled by the beauty of this place and the ubiquitous spirit of the Delbrück "phage group" era 🧬🌊🦪
Marc Erhardt retweeted
Exited to share our preprint on the structure of a Salmonella contractile injection system 🥳 Wonderful work by first author @Rooshanie Ejaz and @CloudyKielkopf, @freddie__martin, @HangryHobbit, @RebrovaEva, great collab with @Salmo_Lab
@UCPH_CPR #cryoem
shorturl.at/QHLpm
Marc Erhardt retweeted
And here it is, the completed BASEL collection finally published as early access in @PLOSBiology - see the thread for more details. 🤗🧬🎣
New #biorxiv preprint I'm quite excited about. We show that the #T3SS of the #flagellum secretes proteins at a rate of 10,000 amino acids per second, resulting in optimized flagellum growth and energy consumption.
biorxiv.org/content/10.1101/…
Now published @PNASNews 🥳
Bacterial motility depends on a critical flagellum length and energy-optimized assembly | PNAS
pnas.org/doi/10.1073/pnas.24…





















