Grateful as well to my beloved @pasteur.fr , the scientific home where I spent the last four amazing years doing #Science and #Microbiology!

La blanca orilla. Y mas allá, la inmensa campiña verde, tendida ante un fugaz amanecer.

¿Qué, Gandalf? ¿Qué se ve?

But the main question was still unanswered: how would a SOD-deficient pathogen face superoxide toxicity without the enzyme that always does the job?

Well, the answer, if you want it, is in our paper. Go check it out! 😉

👇👇
journals.asm.org/doi/10.1128/...

But we like to play: what happens if you return them the gene they lost? What happens if you give them back the SOD gene? Will they become more superoxide resistant? Surprisingly, they didn't!
See our Fig 2!

Evolution always goes first, so we figured that the ancestor of these bacteria had a SOD and that they lost it on their way to becoming pathogens... Interesting, right? Check our Fig. 1 here!
journals.asm.org/doi/10.1128/...

So we embarked on a risky adventure: we took one of these SOD-deficient pathogenic aerobes and decided not to leave the enterprise until we had an answer on how these organisms faced oxygen toxicity against all odds
Guess what? This organism was a spirochete: L. interrogans #SpirochetesAreDifferent

However, the advent of next-generation sequencing revealed hundreds of microorganisms across all branches of the tree of life that did NOT have any superoxide detoxification system, thus questioning everything again!
See Fig 1 in Sendra et al. Nat Eco Evol (2023)
www.nature.com/articles/s41...

In 1986, Carlioz & Touati finally proved that SOD-lacking E. coli could not grow in the presence of oxygen unless AAs were added to the media. This closed the debate, and similar observations were reported in yeast and Drosophila.
👇
pmc.ncbi.nlm.nih.gov/articles/PMC...

The seminal paper in 1979 by Fridovich & coll. predicted that aerobes must have superoxide detoxification systems, but this was highly controversial for over a decade (see James A Fee papers) until, in 1986, a milestone paper was published.
www.pnas.org/doi/abs/10.1...

Oxygen is toxic for living beings (believe it or not), but recent studies showed that 10% of them do not care much about it. We were convinced there was a missing key piece in this puzzle and, after hard work and countless thinking hours 🤔, we think we have found an answer 👇🧵