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Julie Pfeiffer

@jkpfeiff.bsky.social

740 followers 150 following 22 posts

Our lab at UT Southwestern studies viral pathogenesis. And sometimes wine.

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Julie Pfeiffer @jkpfeiff.bsky.social · Aug 18

What we offer:
Activities that build community and collaboration. (5/5)

Photos of lab member teams participating in the Microbiology Olympics.

Photo showing our seminar room transformed into the set for Faculty Feud.

Lab teams face off at Faculty Feud.

Julie Pfeiffer @jkpfeiff.bsky.social · Aug 18

What we offer:
Consideration for our Endowed Scholars Program (large start-up package). (4/5) www.utsouthwestern.edu/education/pr...

Endowed Scholars Program in Medical Science

The Endowed Scholars Program in Medical Science provides generous financial support to newly appointed tenure-track Assistant Professors at UT Southwestern.

www.utsouthwestern.edu

Julie Pfeiffer @jkpfeiff.bsky.social · Aug 18

What we offer:
Faculty mentoring (grant writing workshops, chalk talks, strategy sessions, etc.). (3/5)

An agenda of discussion topics at a recent grant workshop, including when a project is ready, organization, scope, avoiding rookie mistakes, reviewer empathy, and what really happens during the review process.

A slide showing strategies for when to submit a grant, with pitfalls for submission too early or too late in the timeline of a given project.

Julie Pfeiffer @jkpfeiff.bsky.social · Aug 18

What we offer:
A highly collaborative and supportive environment that enables innovative science. (2/5) www.utsouthwestern.edu/departments/...

A photo of department members and a list of faculty and trainee awards including NIH Pioneer, NIH New Innovator, HHMI Faculty Scholars, Pew Scholar, Searle Scholar, BWF-PATH awardees, HHMI Hanna Gray Fellows, HHMI Gilliam Fellow, NSF Fellows.

Julie Pfeiffer @jkpfeiff.bsky.social · Aug 18

Faculty search announcement 2025: Tenure-Track Assistant Professor in Microbiology at UT Southwestern. We seek candidates working in microbial pathogenesis (some preference may be given to bacterial pathogens). Come join our community! (1/5) www.utsouthwestern.edu/departments/...

Department members sit at a very long table in the hallway eating a pre-Thanksgiving potluck feast.

Reposted by Julie Pfeiffer

Kevin Forsberg @kvnforsberg.bsky.social · Jul 29

Very proud to have our lab’s first work published in @cp-cellhostmicrobe.bsky.social!

In this work, we use functional metagenomics to find phage defenses from human and soil microbiomes!

Congrats to first author @luis840alberto.bsky.social !

www.cell.com/cell-host-mi...

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Julie Pfeiffer @jkpfeiff.bsky.social · Jul 1

Exciting news: Carla Saleh is now Chair of Virology at Pasteur! Congrats to Carla and all who will benefit from her exceptional leadership!

SalehLab @salehlabparis.bsky.social · Jul 1

Thrilled (and humbled!) to share that since today I am the Chair of the Virology Department at @pasteur.fr. Grateful to my colleagues for their trust. Now let’s push the frontiers of virus research together. The sky is the limit! 🦠🔬 #Virology #Science #TeamPasteur

Julie Pfeiffer @jkpfeiff.bsky.social · Jun 25

Finally, huge congrats to Valerie on this story, which spanned virology, genetics, cell biology, biochemistry, and mouse infections (thanks to @robertmaples.bsky.social‬ for help with mouse work!). She defended her thesis last week and will start a postdoc with @msdiamondlab.bsky.social‬ soon! 10/10

After defending her Ph.D. thesis Valerie hits the "EASY" button, which says, "that was easy". She celebrates.

Julie Pfeiffer @jkpfeiff.bsky.social · Jun 25

Thanks to the reviewers and editor Ken Cadwell for their very helpful/constructive comments that improved our paper. Their reviews and our responses are available here under the Peer Review tab: journals.plos.org/plosbiology/... 9/10

Julie Pfeiffer @jkpfeiff.bsky.social · Jun 25

This story illustrates why we love forward genetic approaches in virology—they reveal unanticipated facets of replication. In a system where any mutation that increases early progeny could be selected, the fact that an egress-enhancing mutation emerged highlights the inefficiency of MNV egress. 8/10

Julie Pfeiffer @jkpfeiff.bsky.social · Jun 25

We don’t know. But it could be: 1) Early cell death reduces total viral yield in the long run. Indeed, we found that WT “catches up” over a full 16 hour single cycle of infection, 2) Early progeny release induces early host immune responses, 3) K40R viruses could have transmission defects. 7/10

Julie Pfeiffer @jkpfeiff.bsky.social · Jun 25

Does NS3-K40R suffer a fitness cost in mice—a complex environment with more selective pressure? Nope. At least not in our relatively short-term infection experiments. So why doesn’t WT virus have arginine at position 40? (Fun fact: human Norwalk virus DOES have arginine at this position.) 6/10

Julie Pfeiffer @jkpfeiff.bsky.social · Jun 25

Instead, NS3-K40R viruses have faster egress from cells due to earlier mitochondrial disruption and cell death. In spite of this conservative amino acid change, NS3 protein containing K40R disrupted liposomes that mimic mitochondrial membranes at concentrations 10-100 fold lower than WT NS3. 5/10

Julie Pfeiffer @jkpfeiff.bsky.social · Jun 25

She identified a mutation in the N terminal domain of NS3—K40R—that was sufficient to increase replication speed. Curiously, the mutation did not alter RNA replication or NTPase activity, two other important functions of NS3. 4/10

Julie Pfeiffer @jkpfeiff.bsky.social · Jun 25

But we didn’t know that when Valerie started her project in 2021. To identify inefficiencies in replication, she used a forward genetic approach to enrich for MNV variants that replicate faster, by collecting the very earliest progeny. (We had IBC approval in advance!) 3/10

Julie Pfeiffer @jkpfeiff.bsky.social · Jun 25

In 2023 our colleagues ‪@tiffanyreeselab.bsky.social‬ & @hanckslab.bsky.social‬ showed MNV egress requires viral NS3, which disrupts mitochondria to induce cell lysis. Without this function of NS3, cells become bags of viruses that can’t escape. 2/10 www.nature.com/articles/s41...

Julie Pfeiffer @jkpfeiff.bsky.social · Jun 25

Valerie Rodriguez Irizarry’s tour de force paper on murine norovirus adaptation/egress is now out in peer-reviewed form ‪@plosbiology.org‬. It highlights the power of forward genetics in virology research. 🧵 1/10 journals.plos.org/plosbiology/...

Drawing of a cell showing mitochondria in the cytoplasm, with murine norovirus virions exiting the cell through damage to the plasma membrane. Image credit: Valerie Rodriguez Irizarry

Photo of Valerie Rodriguez Irizarry

Julie Pfeiffer @jkpfeiff.bsky.social · Apr 28

Terry Dermody and I wrote an op-ed about chronic diseases ("Make America Healthy Again"), the role of viral infections, and how virologists can help. www.post-gazette.com/opinion/gues...

Terrence S. Dermody and Julie K. Pfeiffer: To tackle chronic disease, turn to the virologists

Despite the United States being a global leader in many areas, Americans are not healthy. Life expectancy is lower than in other industrialized nations,...

www.post-gazette.com

Reposted by Julie Pfeiffer

DermodyLab @dermodylab.bsky.social · Apr 24

🚨 New paper out!
"A single mutation in an enteric virus alters tropism and sensitivity to microbiota"
One tiny change, big consequences.
A great collab with the Julie Pfeiffer lab! @jkpfeiff.bsky.social
Read here: bit.ly/42sD2rX
#Virology #Microbiome #Science

Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans...

Reposted by Julie Pfeiffer

Kevin Forsberg @kvnforsberg.bsky.social · Mar 3

My lab’s first preprint!

We used functional metagenomics to identify phage defenses in human and soil microbiomes. We scaled these selections while maintaining accuracy, enabling us to examine 9 habitats for defense elements against 7 phages.

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

1/10

Functional Metagenomic Selections for Phage Defense

Julie Pfeiffer @jkpfeiff.bsky.social · Feb 26

New preprint from Valerie Rodriguez-Irizarry in our group-- her tour de force thesis work used forward genetics to discover new insights into non-enveloped viral egress.
www.biorxiv.org/content/10.1...

An extremely talented female scientist smiles.

Reposted by Julie Pfeiffer

Scott Saunders @saunderslab.bsky.social · Nov 22

Wow - bluesky! 📈 🦠

Please help me amplify a special faculty search. We're looking for someone in "Microbial Systems Biology" to join me and @kreynoldslab.bsky.social at UTSW Sys Bio / Bioinformatics.

There is an empty lab space right next to us waiting for you!

apply.interfolio.com/154339

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chalk + chalkboard with diagrams

lab group silly picture

Julie Pfeiffer @jkpfeiff.bsky.social · Nov 22

Microbiology Department potluck lunch ✨

Julie Pfeiffer @jkpfeiff.bsky.social · Oct 31

Happy halloween.

Reposted by Julie Pfeiffer

Bill Jackson @wtjackson.bsky.social · Oct 19

This Saturday on the Yale campus Nobel laureate Charlie Rice will lecture in honor of Dr. Brett Lindenbach. A link for seeing the event remotely is below. A chance to celebrate all the wonderful professional and personal connections many of us have with Brett. yale.hosted.panopto.com/Panopto/Page...