Arthur Charles-Orszag

Tomorrow!! Special Pohlschröder lab double feature, because we halove their work (going to pun hell now)

Archaeasalutations!! Archaea Power Hour is back tomorrow (Wednesday) at 10 AM EST / 4 PM CET!! Check your email for the Zoom link or sign up to join our mailing list here: docs.google.com/forms/d/e/1FAI…. Check out the two exciting talks we have planned for you:

Stunning! Congrats @buzzbaum.bsky.social et al!

Rest in power Zara, you’ll be missed

Serial innovations by Asgard archaea shaped the DNA replication machinery of the early eukaryotic ancestor - Nature Ecology & Evolution Phylogenetic and biochemical analyses show a diversity of components of the DNA replication machinery in different Asgard archaea that contributed to the eukaryotic DNA replication machinery.

Glad to share our paper out today @NatureEcoEvo: “Serial innovations by Asgard archaea shaped the DNA replication machinery of the early eukaryotic ancestor”. www.nature.com/articles/s41... #microsky #archaeasky

Don’t miss the first APH meeting of the season this coming Wednesday!

Welcome to our first postdoc in the ACO Lab, Andy Garcia! 🎉

Supporting each other as #newPI is very important, and @antonioserapio.bsky.social is great at it

🚨 🚨 🗓️ The deadline to submit your abstract for the #ASCB2025 meeting in Philadelphia is this Wednesday, September 3!!
Dyche Mullins and I are hosting the session “Cell Biology at the Extremes”. Thermophiles, psychrophiles, tardigrades, giant bacteria… now is your time to shine!! 🚨

New hot fluorescent tag dropped!

Thank you!

We’ve uncovered Asgard chromatin structures formed by a Hodarchaeal histone : closed hypernucleosome conserved in archaea and an open form resembling the H3-H4 eukaryotic octasome. Fantastic work by @harshranawat.bsky.social!
www.biorxiv.org/content/10.1...
#Chromatin #Asgard #Archaea #cryoEM

Thanks!

Archaeal S-layer proteins can adopt different symmetries that can locally accommodate areas of high curvature. The S-layer is also involved in the control of turgor and osmotic pressure, ion transport, cell-cell interactions and mating.

The S-layer is the most widespread and fundamental component of archaeal cell envelopes and may represent one of the earliest and most fundamental cell wall polymers found in microorganisms

The archaeal S-layer is not only pretty, it also carries crucial cellular functions, and the list keeps growing! @sshamphavi.bsky.social @marleenvw.bsky.social @archaellum.bsky.social and I wrote a little sheath sheet (+10 pts if you got the pun)
📖 Curr Opin Cell Biol
🔗 doi.org/10.1016/j.ce...

What a year for the cell biology of archaeal chromosome segregation! 🧬 @joeparham19.bsky.social and @buzzbaum.bsky.social now add pieces to the SegAB puzzle by connecting it with cell division

Archaeal SegAB forms a bipolar structure that promotes chromosome segregation in spherical cells Archaeal segAB operons are thought to promote chromosome segregation, but their mechanism remains unknown. We employ comparative genomics, structural biology, genetic knockouts, and quantitative cell ...

To explore how ring assembly and DNA segregation might be coupled, we turned our attention to the ParA homologue, SegA, and its partner SegB, using antibodies kindly gifted by @acharlesorszag.bsky.social (see www.biorxiv.org/content/10.1...)

In just 2 days on WEDNESDAY, May 14th at 10 AM EST / 4 PM CET, @fabaiwu.bsky.social will kick off our last spring APH session by telling us about his new research investigating the evolution of DNA replication machineries from Archaea to Eukaryotes!!! Visit our website (link in bio) for more info!

Think you're under pressure? Marion Illartin will close out our last APH session of the semester by telling us about her multidisciplinary approach to characterize how pressure regulates the SurR transcription factor in everyone's favorite barophile, Thermococcus barophilus!! Zoom in on May 14th!

Don’t miss it!! Last APH of the season 🫶🏼

Oop!

If I may weigh in here: I avoid overfixing the cells, especially if using glutaraldehyde that can induce significant artefacts. I usually do 30-60 min at RT and rinse abundantly in buffer. Fixed cells in buffer can then be kept for days in the fridge :)

Hahaha awww 🫶🏼 I’m very ignorant when it comes to anaerobic cultures. What are the challenging steps pre-fixation? The spinning?

6) in all subsequent rinsing and post-fixation steps, avoid drying the cells as much as possible. We never discard the full volume of liquid in the wells. Instead, we only discard 80-90% but make up for it by performing more rinsing steps

5) add an equal volume of a 2X fixative solution in adequate buffer, or ideally in culture media, as opposed to removing the media and then adding 1X fixative to the cells

4) spin the plate containing the cells/coverslips (24-well plate, 13 mm coverslips in our hands) at 1,000xg for 2 min to increase cell density on the coverslip

3) incubate high OD live cultures on coated coverslips for 30-60 min to allow plenty of cells to settle. It works better than trying to adhere chemically fixed cells.

2) try poly-D-lysine instead. Sometimes it just works!

You can enhance adhesion by doing any, or a combination, of the following:

1) plasma treat the glass coverslips before coating them with poly-L-lysine (30 min at RT). This greatly enhance coating strength. Make sure to rinse with plenty of water before adding live cells