Simonetta Gribaldo

@sgribaldo.bsky.social

Evolutionary microbiologist. Head of lab at Institut Pasteur, Paris. Microbial diversity and evolution. Phylogenomics, Tree of Life, Envelopes, Methanogens.
https://research.pasteur.fr/en/team/evolutionary-biology-of-the-microbial-cell/

@cellforganized.bsky.socialReposted by @sgribaldo.bsky.social

Applications are now being accepted for the 2027 Bacterial Cell Biology & Development GRC, June 6–11! GRS will be on June 5-6, 2027 We’ll likely be oversubscribed, so please apply early!

@sgribaldo.bsky.social

We are particularly proud of this work given the upcoming 50th anniversary of the discovery of Archaea in 1977 (same year Punk broke 😉) They continue to hold big surprises impacting all aspects of microbiology and evolution. Hope it'll encourage more young scientists to join this exciting field! 9/9

A free "archaeal" re-interpretation of the famous slogan "Punk's not dead", made by AI and just meant to be funny ;-)
@sgribaldo.bsky.social

Building upon the legacy of Kandler and König, our findings reshape a 50-year-old view on archaeal PG structure. Given the importance of methanogens in ecology, biotechnology, and the animal&human microbiomes, these results open new avenues to study their biology and evolution 7/9
#ArchaeaSky

@sgribaldo.bsky.social

ArmA is conserved in all PG-bearing methanogens and beautifully localizes at the division site. Our deletion mutant confirms that this enzyme is required for cell division, hydrolysing archaeal PG to complete cytokinesis and cell separation 6/9

Epifluorescence microscopy showing ArmA localisation at the division site in Methanobrevibacter smithii at different stages of the cell cycle
@sgribaldo.bsky.social

Digestion of archaeal PG with ArmA and its analysis by NMR and LC-MS/MS reveals a new chemical structure ! It shows key novel features with respect to the current model, including a previously undescribed sugar that we name N-acetylarmosamine (ArmNAc) 5/9

The new structure of archaeal PG (left) as compared to the one by Kandler and Konig from the 70s (right)
@sgribaldo.bsky.social

Our group teamed up with @ivo-boneca.bsky.social and Inaki Guijarro at the NMR facility @pasteur.fr to look at archaeal PG structure with modern approaches. Using a combination of bioinformatics, zymograms, and MS, we identified the first archaeal PG-cleaving glycosyl hydrolase that we name ArmA 4/9

Domain architecture of ArmA
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