Holly Rucker (@hollyrucker)

Latest work! 🧬

We uncover how evolution of translation initiation factor 2 (IF2) extensions links translation to bacterial stress response. We map 7 structural architectures & show how terminal extensions are enriched in intrinsic disorder & phase-separation features.

Link: doi.org/10.64898/202...

11.02.2026 18:18 👍 25 🔁 13 💬 2 📌 0

Ecological constraints and evolutionary trade-offs shape nitrogen fixation across habitats Abstract. From its earliest beginnings, life’s expansion into new habitats has been profoundly shaped by its reciprocal interactions with Earth’s changing

New paper! Why are some Nitrogen fixing microbes more complex?

@msobol.bsky.social et al. find that microbes with more N2-fixation genes have larger, more versatile genomes, showing how changing environments shaped this key metabolism!

> academic.oup.com/ismecommun/a... @isme-microbes.bsky.social

06.02.2026 16:44 👍 12 🔁 11 💬 0 📌 0

NASA NASA.gov brings you the latest news, images and videos from America's space agency, pioneering the future in space exploration, scientific discovery and aeronautics research.

Our latest paper on ancient microbes and nitrogen is featured on the NASA website today! 🚀🔬Way to go, @hollyrucker.bsky.social!

Resurrecting Ancient Enzymes in NASA’s Search for Life Beyond Earth
www.nasa.gov

Paper link: www.nature.com/articles/s41... #astrobiology @uwmadscience.bsky.social

02.02.2026 16:02 👍 9 🔁 4 💬 0 📌 0

I also want to give a big shoutout to our amazing collaborators on this paper, especially fellow grad student Kunmanee, who trained me on using the IRMS!

30.01.2026 23:09 👍 0 🔁 0 💬 0 📌 0

Resurrected nitrogenases recapitulate canonical N-isotope biosignatures over two billion years - Nature Communications The study shows that nitrogenase enzymes have maintained stable isotope signatures over billions of years, revealing how ancient microbes shaped Earth’s nitrogen cycle and offering a new experimental ...

Our new paper, out today! We resurrected ancient nitrogenases first used by life on Earth 3 billion years ago. We combined synthetic biology and geology & validated their chemical #biosignature in rocks that helps reveal ancient life on Earth!(and beyond!)

Link: www.nature.com/articles/s41...

30.01.2026 21:12 👍 66 🔁 23 💬 2 📌 3

Resurrecting Ancient Enzymes in NASA's Search for Life Beyond Earth - NASA Science NASA-supported scientists have resurrected an enzyme first used by organisms on Earth 3.2-billion years ago and, in the process, have validated a chemical

Happy to share that a fantastic article about my latest research was just published on NASA’s website! Very grateful to have such a spotlight on my PhD research and recent Nature Communications paper.

30.01.2026 18:28 👍 9 🔁 3 💬 2 📌 0

A very cool little announcement I saw on my Google Scholar page today!

19.01.2026 19:18 👍 5 🔁 1 💬 0 📌 0

Having a wonderful time at the Geobiology GRC (and GRS) this week! 🦠🪨🧬

15.01.2026 23:37 👍 4 🔁 1 💬 0 📌 0

Consider submitting a #AbSciCon2026 abstract to our session on transition metals!

#abscicon26 #geobiology

13.01.2026 22:39 👍 4 🔁 3 💬 0 📌 0

IsoCamp was one of the most rewarding experiences of my PhD thus far-I highly recommend it for anyone interested in stable isotopes!

09.01.2026 00:34 👍 1 🔁 1 💬 0 📌 0

🚀 Planning to attend #AbSciCon2026 and study the role of metals in life evolution and life elsewhere? Then consider submitting an abstract to our session #20- Transition Metals in Habitability and Biological Evolution. Details below and at this link: agu.confex.com/agu/abscicon...

31.12.2025 22:01 👍 10 🔁 4 💬 0 📌 1

We are now accepting abstracts for our session: Transition Metals in Habitability and Biological Evolution for AbSciCon 26! 🪨🧪🦠

Abstract submissions are open until Jan 14: agu.confex.com/agu/abscicon...

#AbSciCon

21.11.2025 19:27 👍 4 🔁 2 💬 0 📌 0

We are now accepting abstracts for our session: Transition Metals in Habitability and Biological Evolution for AbSciCon 26! 🪨🧪🦠

Abstract submissions are open until Jan 14: agu.confex.com/agu/abscicon...

#AbSciCon

21.11.2025 19:27 👍 4 🔁 2 💬 0 📌 0

Early Career Scientist Awards 2026 Application to the UW-Madison Evolution Seminar Series - Early Career Scientist Awards.

Wisconsin Evolution is accepting applications for our Seminar Series' Early Career Scientist Award. Come share your evolution research and visit UW-Madison's evolution community. Open to grad students and postdocs (<5 yrs post PhD) from outside UW-Madison.

Apply by Dec 15th here: shorturl.at/4a4O6

19.11.2025 20:55 👍 38 🔁 54 💬 2 📌 1

Has anyone here used stoggles and liked them? I would love to not have to switch between my safety glasses and regular glasses constantly in lab but they are a bit pricey 🥽

07.11.2025 21:35 👍 0 🔁 0 💬 0 📌 0

🎉 Huge congrats to Holly Rucker for winning First Place in the Midwest Geobiology Conference Best Oral Presentation! 🏆 Amazing work, Holly! @uwmadscience.bsky.social @uwbact.bsky.social @hollyrucker.bsky.social #UWMad

31.10.2025 18:45 👍 4 🔁 1 💬 0 📌 0

Image with a blue to purple gradient in the background with graphics of a planet, sunset on water, DNA & an Erlenmeyer flask, with text "WiCOR seeks a Postdoctoral Fellow, Apply by Nov 15, Learn more at wicor.wisc.edu/postdoc"

WiCOR seeks a #postdoctoral fellow to participate in Center #research in any discipline related to our two main research questions:
1. How do habitable planets form? 🪐
2. How does life emerge on habitable planets? 🧬

Full information at: wicor.wisc.edu/postdoc/

Apply by Nov 15

🔭 🧪
#postdoc #hiring

27.10.2025 16:19 👍 8 🔁 3 💬 0 📌 2

currently reading: The Sea Around Us

I somehow have never read any of Rachel Carson’s books so I am making up for that now!

11.10.2025 17:38 👍 2 🔁 0 💬 0 📌 0

I had a great time being interviewed for this!

10.10.2025 21:56 👍 5 🔁 2 💬 0 📌 0

currently reading Strata by Laura Poppick-looking forward to her talk for the WI Book Festival!

03.10.2025 22:27 👍 2 🔁 0 💬 0 📌 0

Happy national dog day from Yuki ♥️

26.08.2025 15:55 👍 1 🔁 0 💬 0 📌 0

Finished some updates to the gas manifold I’ve been building and turned it on for the first time today- it works great 🥹🙌🏻

09.07.2025 21:59 👍 9 🔁 1 💬 0 📌 0

Microbial N2O reduction in sulfidic waters: Implications for Proterozoic oceans Throughout Earth’s history, shifts in ocean redox influenced the bioavailability of trace metals, shaping the activity of microorganisms. In Proterozoic oceans, the precipitation of copper (Cu) with sulfide was hypothesized to limit the bioavailability of Cu. This limitation may have suppressed microbial reduction of nitrous oxide (N2O), due to the Cu dependency of nitrous oxide reductase (Nos). It is thought that without this critical microbial sink, Proterozoic oceans were a significant net source of N2O. Here, we revisit this paradigm in light of recently derived ∼20-fold lower estimates for sulfide in Proterozoic seawater and an empirical evaluation of the potential for microbial N2O reduction under sulfidic conditions. Leveraging publicly available environmental metatranscriptomes, we infer active N2O reduction from the detection of nosZ transcripts in multiple marine and lacustrine systems in which sulfide and Cu concentrations are analogous to those of the Proterozoic. In controlled culture experiments, we demonstrate that the purple non-sulfur bacterium Rhodopseudomonas palustris can reduce N2O at sulfide concentrations up to 100 µM, well above levels predicted for Proterozoic oceans. Based on trace metal speciation modeling, we suggest that Cu remains bioavailable under Proterozoic-like conditions as a dissolved CuHS complex. Using phylogenetics, we infer that early N2O reducers were probably anoxygenic phototrophs and performed N2O reduction as dark metabolism. Collectively, these observations suggest microbial N2O reduction occurs under euxinic conditions, implying that Proterozoic marine N2O emissions were substantially lower than previously proposed. Our conclusions inform our understanding of the microbial ecology in sulfidic waters, the early climate, and the search for extraterrestrial life. ### Competing Interest Statement The authors have declared no competing interest. National Aeronautics and Space Administration, https://ror.org/027ka1x80, 80NSSC17K0296

New preprint on ancient oceans!

We challenge the idea of early Earth as major N2O source; reshaping views on climate & biosignatures. Led by S. Buessecker @annedekas.bsky.social lab!

➡️ Microbial N2O reduction in sulfidic waters: Implications for Proterozoic oceans
www.biorxiv.org/content/10.1...

07.07.2025 16:31 👍 15 🔁 7 💬 0 📌 0

I feel like Zotero’s upload feature only successfully copies over the citation info about 50% of the time 😓

30.06.2025 21:53 👍 0 🔁 0 💬 0 📌 0

Been analyzing vacuña bone, tooth (left) and collagen (right) for C/N/O isotopes this week at IsoCamp! @isocampunm.bsky.social

21.06.2025 18:41 👍 3 🔁 1 💬 0 📌 0

Added some amazing prints by @drlperezdiaz.bsky.social to the lab!

13.06.2025 15:53 👍 8 🔁 2 💬 1 📌 0

Had my third year committee meeting yesterday (went great!) so I made a cannoli bundt cake to celebrate 🍰 not the best photos but it tasted amazing

05.06.2025 16:30 👍 1 🔁 1 💬 0 📌 0

iron toxicity model

New preprint: eukaryotic origins! 🥁

We propose that iron -not oxygen- may have delayed the rise of complex life. Our model reframes the “oxygen delay” puzzle: the gap between atmospheric O2 and early eukaryotic fossils may reflect iron-mediated stress, not for O2:

www.biorxiv.org/content/10.1...

02.06.2025 18:19 👍 48 🔁 19 💬 2 📌 3

🚨 I’m hiring a postdoc for Fall 2025 with experience in microbial ‘omics data analysis and phylogenetics/genomics. Projects will be centered around ancient microbial ecology & evolution. Click here for more information: bpb-us-e1.wpmucdn.com/wp.txstate.e...

Please share, thank you 🙏🏻

28.05.2025 15:17 👍 41 🔁 46 💬 1 📌 2

Excited to share what I’ve been working on for the first part of my PhD!

27.05.2025 20:46 👍 4 🔁 2 💬 0 📌 0

Holly Rucker

Latest posts by Holly Rucker @hollyrucker